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* [gcc(refs/users/marxin/heads/sphinx-v6)] Remove tm.texi.in.
@ 2022-03-15 14:17 Martin Liska
0 siblings, 0 replies; 2+ messages in thread
From: Martin Liska @ 2022-03-15 14:17 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:70c550a72d4838565b6626f50d9e1f73353cb59f
commit 70c550a72d4838565b6626f50d9e1f73353cb59f
Author: Martin Liska <mliska@suse.cz>
Date: Tue Mar 15 14:33:13 2022 +0100
Remove tm.texi.in.
Diff:
---
gcc/doc/tm.texi.in | 8185 ----------------------------------------------------
1 file changed, 8185 deletions(-)
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
deleted file mode 100644
index f869ddd5e5b..00000000000
--- a/gcc/doc/tm.texi.in
+++ /dev/null
@@ -1,8185 +0,0 @@
-@c Copyright (C) 1988-2022 Free Software Foundation, Inc.
-@c This is part of the GCC manual.
-@c For copying conditions, see the file gcc.texi.
-
-@node Target Macros
-@chapter Target Description Macros and Functions
-@cindex machine description macros
-@cindex target description macros
-@cindex macros, target description
-@cindex @file{tm.h} macros
-
-In addition to the file @file{@var{machine}.md}, a machine description
-includes a C header file conventionally given the name
-@file{@var{machine}.h} and a C source file named @file{@var{machine}.c}.
-The header file defines numerous macros that convey the information
-about the target machine that does not fit into the scheme of the
-@file{.md} file. The file @file{tm.h} should be a link to
-@file{@var{machine}.h}. The header file @file{config.h} includes
-@file{tm.h} and most compiler source files include @file{config.h}. The
-source file defines a variable @code{targetm}, which is a structure
-containing pointers to functions and data relating to the target
-machine. @file{@var{machine}.c} should also contain their definitions,
-if they are not defined elsewhere in GCC, and other functions called
-through the macros defined in the @file{.h} file.
-
-@menu
-* Target Structure:: The @code{targetm} variable.
-* Driver:: Controlling how the driver runs the compilation passes.
-* Run-time Target:: Defining @samp{-m} options like @option{-m68000} and @option{-m68020}.
-* Per-Function Data:: Defining data structures for per-function information.
-* Storage Layout:: Defining sizes and alignments of data.
-* Type Layout:: Defining sizes and properties of basic user data types.
-* Registers:: Naming and describing the hardware registers.
-* Register Classes:: Defining the classes of hardware registers.
-* Stack and Calling:: Defining which way the stack grows and by how much.
-* Varargs:: Defining the varargs macros.
-* Trampolines:: Code set up at run time to enter a nested function.
-* Library Calls:: Controlling how library routines are implicitly called.
-* Addressing Modes:: Defining addressing modes valid for memory operands.
-* Anchored Addresses:: Defining how @option{-fsection-anchors} should work.
-* Condition Code:: Defining how insns update the condition code.
-* Costs:: Defining relative costs of different operations.
-* Scheduling:: Adjusting the behavior of the instruction scheduler.
-* Sections:: Dividing storage into text, data, and other sections.
-* PIC:: Macros for position independent code.
-* Assembler Format:: Defining how to write insns and pseudo-ops to output.
-* Debugging Info:: Defining the format of debugging output.
-* Floating Point:: Handling floating point for cross-compilers.
-* Mode Switching:: Insertion of mode-switching instructions.
-* Target Attributes:: Defining target-specific uses of @code{__attribute__}.
-* Emulated TLS:: Emulated TLS support.
-* MIPS Coprocessors:: MIPS coprocessor support and how to customize it.
-* PCH Target:: Validity checking for precompiled headers.
-* C++ ABI:: Controlling C++ ABI changes.
-* D Language and ABI:: Controlling D ABI changes.
-* Named Address Spaces:: Adding support for named address spaces
-* Misc:: Everything else.
-@end menu
-
-@node Target Structure
-@section The Global @code{targetm} Variable
-@cindex target hooks
-@cindex target functions
-
-@deftypevar {struct gcc_target} targetm
-The target @file{.c} file must define the global @code{targetm} variable
-which contains pointers to functions and data relating to the target
-machine. The variable is declared in @file{target.h};
-@file{target-def.h} defines the macro @code{TARGET_INITIALIZER} which is
-used to initialize the variable, and macros for the default initializers
-for elements of the structure. The @file{.c} file should override those
-macros for which the default definition is inappropriate. For example:
-@smallexample
-#include "target.h"
-#include "target-def.h"
-
-/* @r{Initialize the GCC target structure.} */
-
-#undef TARGET_COMP_TYPE_ATTRIBUTES
-#define TARGET_COMP_TYPE_ATTRIBUTES @var{machine}_comp_type_attributes
-
-struct gcc_target targetm = TARGET_INITIALIZER;
-@end smallexample
-@end deftypevar
-
-Where a macro should be defined in the @file{.c} file in this manner to
-form part of the @code{targetm} structure, it is documented below as a
-``Target Hook'' with a prototype. Many macros will change in future
-from being defined in the @file{.h} file to being part of the
-@code{targetm} structure.
-
-Similarly, there is a @code{targetcm} variable for hooks that are
-specific to front ends for C-family languages, documented as ``C
-Target Hook''. This is declared in @file{c-family/c-target.h}, the
-initializer @code{TARGETCM_INITIALIZER} in
-@file{c-family/c-target-def.h}. If targets initialize @code{targetcm}
-themselves, they should set @code{target_has_targetcm=yes} in
-@file{config.gcc}; otherwise a default definition is used.
-
-Similarly, there is a @code{targetm_common} variable for hooks that
-are shared between the compiler driver and the compilers proper,
-documented as ``Common Target Hook''. This is declared in
-@file{common/common-target.h}, the initializer
-@code{TARGETM_COMMON_INITIALIZER} in
-@file{common/common-target-def.h}. If targets initialize
-@code{targetm_common} themselves, they should set
-@code{target_has_targetm_common=yes} in @file{config.gcc}; otherwise a
-default definition is used.
-
-Similarly, there is a @code{targetdm} variable for hooks that are
-specific to the D language front end, documented as ``D Target Hook''.
-This is declared in @file{d/d-target.h}, the initializer
-@code{TARGETDM_INITIALIZER} in @file{d/d-target-def.h}. If targets
-initialize @code{targetdm} themselves, they should set
-@code{target_has_targetdm=yes} in @file{config.gcc}; otherwise a default
-definition is used.
-
-@node Driver
-@section Controlling the Compilation Driver, @file{gcc}
-@cindex driver
-@cindex controlling the compilation driver
-
-@c prevent bad page break with this line
-You can control the compilation driver.
-
-@defmac DRIVER_SELF_SPECS
-A list of specs for the driver itself. It should be a suitable
-initializer for an array of strings, with no surrounding braces.
-
-The driver applies these specs to its own command line between loading
-default @file{specs} files (but not command-line specified ones) and
-choosing the multilib directory or running any subcommands. It
-applies them in the order given, so each spec can depend on the
-options added by earlier ones. It is also possible to remove options
-using @samp{%<@var{option}} in the usual way.
-
-This macro can be useful when a port has several interdependent target
-options. It provides a way of standardizing the command line so
-that the other specs are easier to write.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac OPTION_DEFAULT_SPECS
-A list of specs used to support configure-time default options (i.e.@:
-@option{--with} options) in the driver. It should be a suitable initializer
-for an array of structures, each containing two strings, without the
-outermost pair of surrounding braces.
-
-The first item in the pair is the name of the default. This must match
-the code in @file{config.gcc} for the target. The second item is a spec
-to apply if a default with this name was specified. The string
-@samp{%(VALUE)} in the spec will be replaced by the value of the default
-everywhere it occurs.
-
-The driver will apply these specs to its own command line between loading
-default @file{specs} files and processing @code{DRIVER_SELF_SPECS}, using
-the same mechanism as @code{DRIVER_SELF_SPECS}.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CPP_SPEC
-A C string constant that tells the GCC driver program options to
-pass to CPP@. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the CPP@.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CPLUSPLUS_CPP_SPEC
-This macro is just like @code{CPP_SPEC}, but is used for C++, rather
-than C@. If you do not define this macro, then the value of
-@code{CPP_SPEC} (if any) will be used instead.
-@end defmac
-
-@defmac CC1_SPEC
-A C string constant that tells the GCC driver program options to
-pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language
-front ends.
-It can also specify how to translate options you give to GCC into options
-for GCC to pass to front ends.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CC1PLUS_SPEC
-A C string constant that tells the GCC driver program options to
-pass to @code{cc1plus}. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the @code{cc1plus}.
-
-Do not define this macro if it does not need to do anything.
-Note that everything defined in CC1_SPEC is already passed to
-@code{cc1plus} so there is no need to duplicate the contents of
-CC1_SPEC in CC1PLUS_SPEC@.
-@end defmac
-
-@defmac ASM_SPEC
-A C string constant that tells the GCC driver program options to
-pass to the assembler. It can also specify how to translate options
-you give to GCC into options for GCC to pass to the assembler.
-See the file @file{sun3.h} for an example of this.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac ASM_FINAL_SPEC
-A C string constant that tells the GCC driver program how to
-run any programs which cleanup after the normal assembler.
-Normally, this is not needed. See the file @file{mips.h} for
-an example of this.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac AS_NEEDS_DASH_FOR_PIPED_INPUT
-Define this macro, with no value, if the driver should give the assembler
-an argument consisting of a single dash, @option{-}, to instruct it to
-read from its standard input (which will be a pipe connected to the
-output of the compiler proper). This argument is given after any
-@option{-o} option specifying the name of the output file.
-
-If you do not define this macro, the assembler is assumed to read its
-standard input if given no non-option arguments. If your assembler
-cannot read standard input at all, use a @samp{%@{pipe:%e@}} construct;
-see @file{mips.h} for instance.
-@end defmac
-
-@defmac LINK_SPEC
-A C string constant that tells the GCC driver program options to
-pass to the linker. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the linker.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac LIB_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The difference
-between the two is that @code{LIB_SPEC} is used at the end of the
-command given to the linker.
-
-If this macro is not defined, a default is provided that
-loads the standard C library from the usual place. See @file{gcc.cc}.
-@end defmac
-
-@defmac LIBGCC_SPEC
-Another C string constant that tells the GCC driver program
-how and when to place a reference to @file{libgcc.a} into the
-linker command line. This constant is placed both before and after
-the value of @code{LIB_SPEC}.
-
-If this macro is not defined, the GCC driver provides a default that
-passes the string @option{-lgcc} to the linker.
-@end defmac
-
-@defmac REAL_LIBGCC_SPEC
-By default, if @code{ENABLE_SHARED_LIBGCC} is defined, the
-@code{LIBGCC_SPEC} is not directly used by the driver program but is
-instead modified to refer to different versions of @file{libgcc.a}
-depending on the values of the command line flags @option{-static},
-@option{-shared}, @option{-static-libgcc}, and @option{-shared-libgcc}. On
-targets where these modifications are inappropriate, define
-@code{REAL_LIBGCC_SPEC} instead. @code{REAL_LIBGCC_SPEC} tells the
-driver how to place a reference to @file{libgcc} on the link command
-line, but, unlike @code{LIBGCC_SPEC}, it is used unmodified.
-@end defmac
-
-@defmac USE_LD_AS_NEEDED
-A macro that controls the modifications to @code{LIBGCC_SPEC}
-mentioned in @code{REAL_LIBGCC_SPEC}. If nonzero, a spec will be
-generated that uses @option{--as-needed} or equivalent options and the
-shared @file{libgcc} in place of the
-static exception handler library, when linking without any of
-@code{-static}, @code{-static-libgcc}, or @code{-shared-libgcc}.
-@end defmac
-
-@defmac LINK_EH_SPEC
-If defined, this C string constant is added to @code{LINK_SPEC}.
-When @code{USE_LD_AS_NEEDED} is zero or undefined, it also affects
-the modifications to @code{LIBGCC_SPEC} mentioned in
-@code{REAL_LIBGCC_SPEC}.
-@end defmac
-
-@defmac STARTFILE_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The
-difference between the two is that @code{STARTFILE_SPEC} is used at
-the very beginning of the command given to the linker.
-
-If this macro is not defined, a default is provided that loads the
-standard C startup file from the usual place. See @file{gcc.cc}.
-@end defmac
-
-@defmac ENDFILE_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The
-difference between the two is that @code{ENDFILE_SPEC} is used at
-the very end of the command given to the linker.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac THREAD_MODEL_SPEC
-GCC @code{-v} will print the thread model GCC was configured to use.
-However, this doesn't work on platforms that are multilibbed on thread
-models, such as AIX 4.3. On such platforms, define
-@code{THREAD_MODEL_SPEC} such that it evaluates to a string without
-blanks that names one of the recognized thread models. @code{%*}, the
-default value of this macro, will expand to the value of
-@code{thread_file} set in @file{config.gcc}.
-@end defmac
-
-@defmac SYSROOT_SUFFIX_SPEC
-Define this macro to add a suffix to the target sysroot when GCC is
-configured with a sysroot. This will cause GCC to search for usr/lib,
-et al, within sysroot+suffix.
-@end defmac
-
-@defmac SYSROOT_HEADERS_SUFFIX_SPEC
-Define this macro to add a headers_suffix to the target sysroot when
-GCC is configured with a sysroot. This will cause GCC to pass the
-updated sysroot+headers_suffix to CPP, causing it to search for
-usr/include, et al, within sysroot+headers_suffix.
-@end defmac
-
-@defmac EXTRA_SPECS
-Define this macro to provide additional specifications to put in the
-@file{specs} file that can be used in various specifications like
-@code{CC1_SPEC}.
-
-The definition should be an initializer for an array of structures,
-containing a string constant, that defines the specification name, and a
-string constant that provides the specification.
-
-Do not define this macro if it does not need to do anything.
-
-@code{EXTRA_SPECS} is useful when an architecture contains several
-related targets, which have various @code{@dots{}_SPECS} which are similar
-to each other, and the maintainer would like one central place to keep
-these definitions.
-
-For example, the PowerPC System V.4 targets use @code{EXTRA_SPECS} to
-define either @code{_CALL_SYSV} when the System V calling sequence is
-used or @code{_CALL_AIX} when the older AIX-based calling sequence is
-used.
-
-The @file{config/rs6000/rs6000.h} target file defines:
-
-@smallexample
-#define EXTRA_SPECS \
- @{ "cpp_sysv_default", CPP_SYSV_DEFAULT @},
-
-#define CPP_SYS_DEFAULT ""
-@end smallexample
-
-The @file{config/rs6000/sysv.h} target file defines:
-@smallexample
-#undef CPP_SPEC
-#define CPP_SPEC \
-"%@{posix: -D_POSIX_SOURCE @} \
-%@{mcall-sysv: -D_CALL_SYSV @} \
-%@{!mcall-sysv: %(cpp_sysv_default) @} \
-%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}"
-
-#undef CPP_SYSV_DEFAULT
-#define CPP_SYSV_DEFAULT "-D_CALL_SYSV"
-@end smallexample
-
-while the @file{config/rs6000/eabiaix.h} target file defines
-@code{CPP_SYSV_DEFAULT} as:
-
-@smallexample
-#undef CPP_SYSV_DEFAULT
-#define CPP_SYSV_DEFAULT "-D_CALL_AIX"
-@end smallexample
-@end defmac
-
-@defmac LINK_LIBGCC_SPECIAL_1
-Define this macro if the driver program should find the library
-@file{libgcc.a}. If you do not define this macro, the driver program will pass
-the argument @option{-lgcc} to tell the linker to do the search.
-@end defmac
-
-@defmac LINK_GCC_C_SEQUENCE_SPEC
-The sequence in which libgcc and libc are specified to the linker.
-By default this is @code{%G %L %G}.
-@end defmac
-
-@defmac POST_LINK_SPEC
-Define this macro to add additional steps to be executed after linker.
-The default value of this macro is empty string.
-@end defmac
-
-@defmac LINK_COMMAND_SPEC
-A C string constant giving the complete command line need to execute the
-linker. When you do this, you will need to update your port each time a
-change is made to the link command line within @file{gcc.cc}. Therefore,
-define this macro only if you need to completely redefine the command
-line for invoking the linker and there is no other way to accomplish
-the effect you need. Overriding this macro may be avoidable by overriding
-@code{LINK_GCC_C_SEQUENCE_SPEC} instead.
-@end defmac
-
-@hook TARGET_ALWAYS_STRIP_DOTDOT
-
-@defmac MULTILIB_DEFAULTS
-Define this macro as a C expression for the initializer of an array of
-string to tell the driver program which options are defaults for this
-target and thus do not need to be handled specially when using
-@code{MULTILIB_OPTIONS}.
-
-Do not define this macro if @code{MULTILIB_OPTIONS} is not defined in
-the target makefile fragment or if none of the options listed in
-@code{MULTILIB_OPTIONS} are set by default.
-@xref{Target Fragment}.
-@end defmac
-
-@defmac RELATIVE_PREFIX_NOT_LINKDIR
-Define this macro to tell @command{gcc} that it should only translate
-a @option{-B} prefix into a @option{-L} linker option if the prefix
-indicates an absolute file name.
-@end defmac
-
-@defmac MD_EXEC_PREFIX
-If defined, this macro is an additional prefix to try after
-@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched
-when the compiler is built as a cross
-compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it
-to the list of directories used to find the assembler in @file{configure.ac}.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{libdir} as the default prefix to
-try when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX_1
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{/lib} as a prefix to try after the default prefix
-when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX_1} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX_2
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{/lib} as yet another prefix to try after the
-default prefix when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX_2} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac MD_STARTFILE_PREFIX
-If defined, this macro supplies an additional prefix to try after the
-standard prefixes. @code{MD_EXEC_PREFIX} is not searched when the
-compiler is built as a cross compiler.
-@end defmac
-
-@defmac MD_STARTFILE_PREFIX_1
-If defined, this macro supplies yet another prefix to try after the
-standard prefixes. It is not searched when the compiler is built as a
-cross compiler.
-@end defmac
-
-@defmac INIT_ENVIRONMENT
-Define this macro as a C string constant if you wish to set environment
-variables for programs called by the driver, such as the assembler and
-loader. The driver passes the value of this macro to @code{putenv} to
-initialize the necessary environment variables.
-@end defmac
-
-@defmac LOCAL_INCLUDE_DIR
-Define this macro as a C string constant if you wish to override the
-standard choice of @file{/usr/local/include} as the default prefix to
-try when searching for local header files. @code{LOCAL_INCLUDE_DIR}
-comes before @code{NATIVE_SYSTEM_HEADER_DIR} (set in
-@file{config.gcc}, normally @file{/usr/include}) in the search order.
-
-Cross compilers do not search either @file{/usr/local/include} or its
-replacement.
-@end defmac
-
-@defmac NATIVE_SYSTEM_HEADER_COMPONENT
-The ``component'' corresponding to @code{NATIVE_SYSTEM_HEADER_DIR}.
-See @code{INCLUDE_DEFAULTS}, below, for the description of components.
-If you do not define this macro, no component is used.
-@end defmac
-
-@defmac INCLUDE_DEFAULTS
-Define this macro if you wish to override the entire default search path
-for include files. For a native compiler, the default search path
-usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR},
-@code{GPLUSPLUS_INCLUDE_DIR}, and
-@code{NATIVE_SYSTEM_HEADER_DIR}. In addition, @code{GPLUSPLUS_INCLUDE_DIR}
-and @code{GCC_INCLUDE_DIR} are defined automatically by @file{Makefile},
-and specify private search areas for GCC@. The directory
-@code{GPLUSPLUS_INCLUDE_DIR} is used only for C++ programs.
-
-The definition should be an initializer for an array of structures.
-Each array element should have four elements: the directory name (a
-string constant), the component name (also a string constant), a flag
-for C++-only directories,
-and a flag showing that the includes in the directory don't need to be
-wrapped in @code{extern @samp{C}} when compiling C++. Mark the end of
-the array with a null element.
-
-The component name denotes what GNU package the include file is part of,
-if any, in all uppercase letters. For example, it might be @samp{GCC}
-or @samp{BINUTILS}. If the package is part of a vendor-supplied
-operating system, code the component name as @samp{0}.
-
-For example, here is the definition used for VAX/VMS:
-
-@smallexample
-#define INCLUDE_DEFAULTS \
-@{ \
- @{ "GNU_GXX_INCLUDE:", "G++", 1, 1@}, \
- @{ "GNU_CC_INCLUDE:", "GCC", 0, 0@}, \
- @{ "SYS$SYSROOT:[SYSLIB.]", 0, 0, 0@}, \
- @{ ".", 0, 0, 0@}, \
- @{ 0, 0, 0, 0@} \
-@}
-@end smallexample
-@end defmac
-
-Here is the order of prefixes tried for exec files:
-
-@enumerate
-@item
-Any prefixes specified by the user with @option{-B}.
-
-@item
-The environment variable @code{GCC_EXEC_PREFIX} or, if @code{GCC_EXEC_PREFIX}
-is not set and the compiler has not been installed in the configure-time
-@var{prefix}, the location in which the compiler has actually been installed.
-
-@item
-The directories specified by the environment variable @code{COMPILER_PATH}.
-
-@item
-The macro @code{STANDARD_EXEC_PREFIX}, if the compiler has been installed
-in the configured-time @var{prefix}.
-
-@item
-The location @file{/usr/libexec/gcc/}, but only if this is a native compiler.
-
-@item
-The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
-
-@item
-The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
-compiler.
-@end enumerate
-
-Here is the order of prefixes tried for startfiles:
-
-@enumerate
-@item
-Any prefixes specified by the user with @option{-B}.
-
-@item
-The environment variable @code{GCC_EXEC_PREFIX} or its automatically determined
-value based on the installed toolchain location.
-
-@item
-The directories specified by the environment variable @code{LIBRARY_PATH}
-(or port-specific name; native only, cross compilers do not use this).
-
-@item
-The macro @code{STANDARD_EXEC_PREFIX}, but only if the toolchain is installed
-in the configured @var{prefix} or this is a native compiler.
-
-@item
-The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
-
-@item
-The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
-compiler.
-
-@item
-The macro @code{MD_STARTFILE_PREFIX}, if defined, but only if this is a
-native compiler, or we have a target system root.
-
-@item
-The macro @code{MD_STARTFILE_PREFIX_1}, if defined, but only if this is a
-native compiler, or we have a target system root.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX}, with any sysroot modifications.
-If this path is relative it will be prefixed by @code{GCC_EXEC_PREFIX} and
-the machine suffix or @code{STANDARD_EXEC_PREFIX} and the machine suffix.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX_1}, but only if this is a native
-compiler, or we have a target system root. The default for this macro is
-@file{/lib/}.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX_2}, but only if this is a native
-compiler, or we have a target system root. The default for this macro is
-@file{/usr/lib/}.
-@end enumerate
-
-@node Run-time Target
-@section Run-time Target Specification
-@cindex run-time target specification
-@cindex predefined macros
-@cindex target specifications
-
-@c prevent bad page break with this line
-Here are run-time target specifications.
-
-@defmac TARGET_CPU_CPP_BUILTINS ()
-This function-like macro expands to a block of code that defines
-built-in preprocessor macros and assertions for the target CPU, using
-the functions @code{builtin_define}, @code{builtin_define_std} and
-@code{builtin_assert}. When the front end
-calls this macro it provides a trailing semicolon, and since it has
-finished command line option processing your code can use those
-results freely.
-
-@code{builtin_assert} takes a string in the form you pass to the
-command-line option @option{-A}, such as @code{cpu=mips}, and creates
-the assertion. @code{builtin_define} takes a string in the form
-accepted by option @option{-D} and unconditionally defines the macro.
-
-@code{builtin_define_std} takes a string representing the name of an
-object-like macro. If it doesn't lie in the user's namespace,
-@code{builtin_define_std} defines it unconditionally. Otherwise, it
-defines a version with two leading underscores, and another version
-with two leading and trailing underscores, and defines the original
-only if an ISO standard was not requested on the command line. For
-example, passing @code{unix} defines @code{__unix}, @code{__unix__}
-and possibly @code{unix}; passing @code{_mips} defines @code{__mips},
-@code{__mips__} and possibly @code{_mips}, and passing @code{_ABI64}
-defines only @code{_ABI64}.
-
-You can also test for the C dialect being compiled. The variable
-@code{c_language} is set to one of @code{clk_c}, @code{clk_cplusplus}
-or @code{clk_objective_c}. Note that if we are preprocessing
-assembler, this variable will be @code{clk_c} but the function-like
-macro @code{preprocessing_asm_p()} will return true, so you might want
-to check for that first. If you need to check for strict ANSI, the
-variable @code{flag_iso} can be used. The function-like macro
-@code{preprocessing_trad_p()} can be used to check for traditional
-preprocessing.
-@end defmac
-
-@defmac TARGET_OS_CPP_BUILTINS ()
-Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
-and is used for the target operating system instead.
-@end defmac
-
-@defmac TARGET_OBJFMT_CPP_BUILTINS ()
-Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
-and is used for the target object format. @file{elfos.h} uses this
-macro to define @code{__ELF__}, so you probably do not need to define
-it yourself.
-@end defmac
-
-@deftypevar {extern int} target_flags
-This variable is declared in @file{options.h}, which is included before
-any target-specific headers.
-@end deftypevar
-
-@hook TARGET_DEFAULT_TARGET_FLAGS
-This variable specifies the initial value of @code{target_flags}.
-Its default setting is 0.
-@end deftypevr
-
-@cindex optional hardware or system features
-@cindex features, optional, in system conventions
-
-@hook TARGET_HANDLE_OPTION
-This hook is called whenever the user specifies one of the
-target-specific options described by the @file{.opt} definition files
-(@pxref{Options}). It has the opportunity to do some option-specific
-processing and should return true if the option is valid. The default
-definition does nothing but return true.
-
-@var{decoded} specifies the option and its arguments. @var{opts} and
-@var{opts_set} are the @code{gcc_options} structures to be used for
-storing option state, and @var{loc} is the location at which the
-option was passed (@code{UNKNOWN_LOCATION} except for options passed
-via attributes).
-@end deftypefn
-
-@hook TARGET_HANDLE_C_OPTION
-This target hook is called whenever the user specifies one of the
-target-specific C language family options described by the @file{.opt}
-definition files(@pxref{Options}). It has the opportunity to do some
-option-specific processing and should return true if the option is
-valid. The arguments are like for @code{TARGET_HANDLE_OPTION}. The
-default definition does nothing but return false.
-
-In general, you should use @code{TARGET_HANDLE_OPTION} to handle
-options. However, if processing an option requires routines that are
-only available in the C (and related language) front ends, then you
-should use @code{TARGET_HANDLE_C_OPTION} instead.
-@end deftypefn
-
-@hook TARGET_OBJC_CONSTRUCT_STRING_OBJECT
-
-@hook TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE
-
-@hook TARGET_OBJC_DECLARE_CLASS_DEFINITION
-
-@hook TARGET_STRING_OBJECT_REF_TYPE_P
-
-@hook TARGET_CHECK_STRING_OBJECT_FORMAT_ARG
-
-@hook TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE
-
-@defmac C_COMMON_OVERRIDE_OPTIONS
-This is similar to the @code{TARGET_OPTION_OVERRIDE} hook
-but is only used in the C
-language frontends (C, Objective-C, C++, Objective-C++) and so can be
-used to alter option flag variables which only exist in those
-frontends.
-@end defmac
-
-@hook TARGET_OPTION_OPTIMIZATION_TABLE
-Some machines may desire to change what optimizations are performed for
-various optimization levels. This variable, if defined, describes
-options to enable at particular sets of optimization levels. These
-options are processed once
-just after the optimization level is determined and before the remainder
-of the command options have been parsed, so may be overridden by other
-options passed explicitly.
-
-This processing is run once at program startup and when the optimization
-options are changed via @code{#pragma GCC optimize} or by using the
-@code{optimize} attribute.
-@end deftypevr
-
-@hook TARGET_OPTION_INIT_STRUCT
-
-@defmac SWITCHABLE_TARGET
-Some targets need to switch between substantially different subtargets
-during compilation. For example, the MIPS target has one subtarget for
-the traditional MIPS architecture and another for MIPS16. Source code
-can switch between these two subarchitectures using the @code{mips16}
-and @code{nomips16} attributes.
-
-Such subtargets can differ in things like the set of available
-registers, the set of available instructions, the costs of various
-operations, and so on. GCC caches a lot of this type of information
-in global variables, and recomputing them for each subtarget takes a
-significant amount of time. The compiler therefore provides a facility
-for maintaining several versions of the global variables and quickly
-switching between them; see @file{target-globals.h} for details.
-
-Define this macro to 1 if your target needs this facility. The default
-is 0.
-@end defmac
-
-@hook TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P
-
-@node Per-Function Data
-@section Defining data structures for per-function information.
-@cindex per-function data
-@cindex data structures
-
-If the target needs to store information on a per-function basis, GCC
-provides a macro and a couple of variables to allow this. Note, just
-using statics to store the information is a bad idea, since GCC supports
-nested functions, so you can be halfway through encoding one function
-when another one comes along.
-
-GCC defines a data structure called @code{struct function} which
-contains all of the data specific to an individual function. This
-structure contains a field called @code{machine} whose type is
-@code{struct machine_function *}, which can be used by targets to point
-to their own specific data.
-
-If a target needs per-function specific data it should define the type
-@code{struct machine_function} and also the macro @code{INIT_EXPANDERS}.
-This macro should be used to initialize the function pointer
-@code{init_machine_status}. This pointer is explained below.
-
-One typical use of per-function, target specific data is to create an
-RTX to hold the register containing the function's return address. This
-RTX can then be used to implement the @code{__builtin_return_address}
-function, for level 0.
-
-Note---earlier implementations of GCC used a single data area to hold
-all of the per-function information. Thus when processing of a nested
-function began the old per-function data had to be pushed onto a
-stack, and when the processing was finished, it had to be popped off the
-stack. GCC used to provide function pointers called
-@code{save_machine_status} and @code{restore_machine_status} to handle
-the saving and restoring of the target specific information. Since the
-single data area approach is no longer used, these pointers are no
-longer supported.
-
-@defmac INIT_EXPANDERS
-Macro called to initialize any target specific information. This macro
-is called once per function, before generation of any RTL has begun.
-The intention of this macro is to allow the initialization of the
-function pointer @code{init_machine_status}.
-@end defmac
-
-@deftypevar {void (*)(struct function *)} init_machine_status
-If this function pointer is non-@code{NULL} it will be called once per
-function, before function compilation starts, in order to allow the
-target to perform any target specific initialization of the
-@code{struct function} structure. It is intended that this would be
-used to initialize the @code{machine} of that structure.
-
-@code{struct machine_function} structures are expected to be freed by GC@.
-Generally, any memory that they reference must be allocated by using
-GC allocation, including the structure itself.
-@end deftypevar
-
-@node Storage Layout
-@section Storage Layout
-@cindex storage layout
-
-Note that the definitions of the macros in this table which are sizes or
-alignments measured in bits do not need to be constant. They can be C
-expressions that refer to static variables, such as the @code{target_flags}.
-@xref{Run-time Target}.
-
-@defmac BITS_BIG_ENDIAN
-Define this macro to have the value 1 if the most significant bit in a
-byte has the lowest number; otherwise define it to have the value zero.
-This means that bit-field instructions count from the most significant
-bit. If the machine has no bit-field instructions, then this must still
-be defined, but it doesn't matter which value it is defined to. This
-macro need not be a constant.
-
-This macro does not affect the way structure fields are packed into
-bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}.
-@end defmac
-
-@defmac BYTES_BIG_ENDIAN
-Define this macro to have the value 1 if the most significant byte in a
-word has the lowest number. This macro need not be a constant.
-@end defmac
-
-@defmac WORDS_BIG_ENDIAN
-Define this macro to have the value 1 if, in a multiword object, the
-most significant word has the lowest number. This applies to both
-memory locations and registers; see @code{REG_WORDS_BIG_ENDIAN} if the
-order of words in memory is not the same as the order in registers. This
-macro need not be a constant.
-@end defmac
-
-@defmac REG_WORDS_BIG_ENDIAN
-On some machines, the order of words in a multiword object differs between
-registers in memory. In such a situation, define this macro to describe
-the order of words in a register. The macro @code{WORDS_BIG_ENDIAN} controls
-the order of words in memory.
-@end defmac
-
-@defmac FLOAT_WORDS_BIG_ENDIAN
-Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or
-@code{TFmode} floating point numbers are stored in memory with the word
-containing the sign bit at the lowest address; otherwise define it to
-have the value 0. This macro need not be a constant.
-
-You need not define this macro if the ordering is the same as for
-multi-word integers.
-@end defmac
-
-@defmac BITS_PER_WORD
-Number of bits in a word. If you do not define this macro, the default
-is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
-@end defmac
-
-@defmac MAX_BITS_PER_WORD
-Maximum number of bits in a word. If this is undefined, the default is
-@code{BITS_PER_WORD}. Otherwise, it is the constant value that is the
-largest value that @code{BITS_PER_WORD} can have at run-time.
-@end defmac
-
-@defmac UNITS_PER_WORD
-Number of storage units in a word; normally the size of a general-purpose
-register, a power of two from 1 or 8.
-@end defmac
-
-@defmac MIN_UNITS_PER_WORD
-Minimum number of units in a word. If this is undefined, the default is
-@code{UNITS_PER_WORD}. Otherwise, it is the constant value that is the
-smallest value that @code{UNITS_PER_WORD} can have at run-time.
-@end defmac
-
-@defmac POINTER_SIZE
-Width of a pointer, in bits. You must specify a value no wider than the
-width of @code{Pmode}. If it is not equal to the width of @code{Pmode},
-you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify
-a value the default is @code{BITS_PER_WORD}.
-@end defmac
-
-@defmac POINTERS_EXTEND_UNSIGNED
-A C expression that determines how pointers should be extended from
-@code{ptr_mode} to either @code{Pmode} or @code{word_mode}. It is
-greater than zero if pointers should be zero-extended, zero if they
-should be sign-extended, and negative if some other sort of conversion
-is needed. In the last case, the extension is done by the target's
-@code{ptr_extend} instruction.
-
-You need not define this macro if the @code{ptr_mode}, @code{Pmode}
-and @code{word_mode} are all the same width.
-@end defmac
-
-@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
-A macro to update @var{m} and @var{unsignedp} when an object whose type
-is @var{type} and which has the specified mode and signedness is to be
-stored in a register. This macro is only called when @var{type} is a
-scalar type.
-
-On most RISC machines, which only have operations that operate on a full
-register, define this macro to set @var{m} to @code{word_mode} if
-@var{m} is an integer mode narrower than @code{BITS_PER_WORD}. In most
-cases, only integer modes should be widened because wider-precision
-floating-point operations are usually more expensive than their narrower
-counterparts.
-
-For most machines, the macro definition does not change @var{unsignedp}.
-However, some machines, have instructions that preferentially handle
-either signed or unsigned quantities of certain modes. For example, on
-the DEC Alpha, 32-bit loads from memory and 32-bit add instructions
-sign-extend the result to 64 bits. On such machines, set
-@var{unsignedp} according to which kind of extension is more efficient.
-
-Do not define this macro if it would never modify @var{m}.
-@end defmac
-
-@hook TARGET_C_EXCESS_PRECISION
-Return a value, with the same meaning as the C99 macro
-@code{FLT_EVAL_METHOD} that describes which excess precision should be
-applied.
-
-@hook TARGET_PROMOTE_FUNCTION_MODE
-
-@defmac PARM_BOUNDARY
-Normal alignment required for function parameters on the stack, in
-bits. All stack parameters receive at least this much alignment
-regardless of data type. On most machines, this is the same as the
-size of an integer.
-@end defmac
-
-@defmac STACK_BOUNDARY
-Define this macro to the minimum alignment enforced by hardware for the
-stack pointer on this machine. The definition is a C expression for the
-desired alignment (measured in bits). This value is used as a default
-if @code{PREFERRED_STACK_BOUNDARY} is not defined. On most machines,
-this should be the same as @code{PARM_BOUNDARY}.
-@end defmac
-
-@defmac PREFERRED_STACK_BOUNDARY
-Define this macro if you wish to preserve a certain alignment for the
-stack pointer, greater than what the hardware enforces. The definition
-is a C expression for the desired alignment (measured in bits). This
-macro must evaluate to a value equal to or larger than
-@code{STACK_BOUNDARY}.
-@end defmac
-
-@defmac INCOMING_STACK_BOUNDARY
-Define this macro if the incoming stack boundary may be different
-from @code{PREFERRED_STACK_BOUNDARY}. This macro must evaluate
-to a value equal to or larger than @code{STACK_BOUNDARY}.
-@end defmac
-
-@defmac FUNCTION_BOUNDARY
-Alignment required for a function entry point, in bits.
-@end defmac
-
-@defmac BIGGEST_ALIGNMENT
-Biggest alignment that any data type can require on this machine, in
-bits. Note that this is not the biggest alignment that is supported,
-just the biggest alignment that, when violated, may cause a fault.
-@end defmac
-
-@hook TARGET_ABSOLUTE_BIGGEST_ALIGNMENT
-
-@defmac MALLOC_ABI_ALIGNMENT
-Alignment, in bits, a C conformant malloc implementation has to
-provide. If not defined, the default value is @code{BITS_PER_WORD}.
-@end defmac
-
-@defmac ATTRIBUTE_ALIGNED_VALUE
-Alignment used by the @code{__attribute__ ((aligned))} construct. If
-not defined, the default value is @code{BIGGEST_ALIGNMENT}.
-@end defmac
-
-@defmac MINIMUM_ATOMIC_ALIGNMENT
-If defined, the smallest alignment, in bits, that can be given to an
-object that can be referenced in one operation, without disturbing any
-nearby object. Normally, this is @code{BITS_PER_UNIT}, but may be larger
-on machines that don't have byte or half-word store operations.
-@end defmac
-
-@defmac BIGGEST_FIELD_ALIGNMENT
-Biggest alignment that any structure or union field can require on this
-machine, in bits. If defined, this overrides @code{BIGGEST_ALIGNMENT} for
-structure and union fields only, unless the field alignment has been set
-by the @code{__attribute__ ((aligned (@var{n})))} construct.
-@end defmac
-
-@defmac ADJUST_FIELD_ALIGN (@var{field}, @var{type}, @var{computed})
-An expression for the alignment of a structure field @var{field} of
-type @var{type} if the alignment computed in the usual way (including
-applying of @code{BIGGEST_ALIGNMENT} and @code{BIGGEST_FIELD_ALIGNMENT} to the
-alignment) is @var{computed}. It overrides alignment only if the
-field alignment has not been set by the
-@code{__attribute__ ((aligned (@var{n})))} construct. Note that @var{field}
-may be @code{NULL_TREE} in case we just query for the minimum alignment
-of a field of type @var{type} in structure context.
-@end defmac
-
-@defmac MAX_STACK_ALIGNMENT
-Biggest stack alignment guaranteed by the backend. Use this macro
-to specify the maximum alignment of a variable on stack.
-
-If not defined, the default value is @code{STACK_BOUNDARY}.
-
-@c FIXME: The default should be @code{PREFERRED_STACK_BOUNDARY}.
-@c But the fix for PR 32893 indicates that we can only guarantee
-@c maximum stack alignment on stack up to @code{STACK_BOUNDARY}, not
-@c @code{PREFERRED_STACK_BOUNDARY}, if stack alignment isn't supported.
-@end defmac
-
-@defmac MAX_OFILE_ALIGNMENT
-Biggest alignment supported by the object file format of this machine.
-Use this macro to limit the alignment which can be specified using the
-@code{__attribute__ ((aligned (@var{n})))} construct for functions and
-objects with static storage duration. The alignment of automatic
-objects may exceed the object file format maximum up to the maximum
-supported by GCC. If not defined, the default value is
-@code{BIGGEST_ALIGNMENT}.
-
-On systems that use ELF, the default (in @file{config/elfos.h}) is
-the largest supported 32-bit ELF section alignment representable on
-a 32-bit host e.g.@: @samp{(((uint64_t) 1 << 28) * 8)}.
-On 32-bit ELF the largest supported section alignment in bits is
-@samp{(0x80000000 * 8)}, but this is not representable on 32-bit hosts.
-@end defmac
-
-@hook TARGET_LOWER_LOCAL_DECL_ALIGNMENT
-
-@hook TARGET_STATIC_RTX_ALIGNMENT
-
-@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align})
-If defined, a C expression to compute the alignment for a variable in
-the static store. @var{type} is the data type, and @var{basic-align} is
-the alignment that the object would ordinarily have. The value of this
-macro is used instead of that alignment to align the object.
-
-If this macro is not defined, then @var{basic-align} is used.
-
-@findex strcpy
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines. Another is to cause character
-arrays to be word-aligned so that @code{strcpy} calls that copy
-constants to character arrays can be done inline.
-@end defmac
-
-@defmac DATA_ABI_ALIGNMENT (@var{type}, @var{basic-align})
-Similar to @code{DATA_ALIGNMENT}, but for the cases where the ABI mandates
-some alignment increase, instead of optimization only purposes. E.g.@
-AMD x86-64 psABI says that variables with array type larger than 15 bytes
-must be aligned to 16 byte boundaries.
-
-If this macro is not defined, then @var{basic-align} is used.
-@end defmac
-
-@hook TARGET_CONSTANT_ALIGNMENT
-
-@defmac LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
-If defined, a C expression to compute the alignment for a variable in
-the local store. @var{type} is the data type, and @var{basic-align} is
-the alignment that the object would ordinarily have. The value of this
-macro is used instead of that alignment to align the object.
-
-If this macro is not defined, then @var{basic-align} is used.
-
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@hook TARGET_VECTOR_ALIGNMENT
-
-@defmac STACK_SLOT_ALIGNMENT (@var{type}, @var{mode}, @var{basic-align})
-If defined, a C expression to compute the alignment for stack slot.
-@var{type} is the data type, @var{mode} is the widest mode available,
-and @var{basic-align} is the alignment that the slot would ordinarily
-have. The value of this macro is used instead of that alignment to
-align the slot.
-
-If this macro is not defined, then @var{basic-align} is used when
-@var{type} is @code{NULL}. Otherwise, @code{LOCAL_ALIGNMENT} will
-be used.
-
-This macro is to set alignment of stack slot to the maximum alignment
-of all possible modes which the slot may have.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@defmac LOCAL_DECL_ALIGNMENT (@var{decl})
-If defined, a C expression to compute the alignment for a local
-variable @var{decl}.
-
-If this macro is not defined, then
-@code{LOCAL_ALIGNMENT (TREE_TYPE (@var{decl}), DECL_ALIGN (@var{decl}))}
-is used.
-
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@defmac MINIMUM_ALIGNMENT (@var{exp}, @var{mode}, @var{align})
-If defined, a C expression to compute the minimum required alignment
-for dynamic stack realignment purposes for @var{exp} (a type or decl),
-@var{mode}, assuming normal alignment @var{align}.
-
-If this macro is not defined, then @var{align} will be used.
-@end defmac
-
-@defmac EMPTY_FIELD_BOUNDARY
-Alignment in bits to be given to a structure bit-field that follows an
-empty field such as @code{int : 0;}.
-
-If @code{PCC_BITFIELD_TYPE_MATTERS} is true, it overrides this macro.
-@end defmac
-
-@defmac STRUCTURE_SIZE_BOUNDARY
-Number of bits which any structure or union's size must be a multiple of.
-Each structure or union's size is rounded up to a multiple of this.
-
-If you do not define this macro, the default is the same as
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac STRICT_ALIGNMENT
-Define this macro to be the value 1 if instructions will fail to work
-if given data not on the nominal alignment. If instructions will merely
-go slower in that case, define this macro as 0.
-@end defmac
-
-@defmac PCC_BITFIELD_TYPE_MATTERS
-Define this if you wish to imitate the way many other C compilers handle
-alignment of bit-fields and the structures that contain them.
-
-The behavior is that the type written for a named bit-field (@code{int},
-@code{short}, or other integer type) imposes an alignment for the entire
-structure, as if the structure really did contain an ordinary field of
-that type. In addition, the bit-field is placed within the structure so
-that it would fit within such a field, not crossing a boundary for it.
-
-Thus, on most machines, a named bit-field whose type is written as
-@code{int} would not cross a four-byte boundary, and would force
-four-byte alignment for the whole structure. (The alignment used may
-not be four bytes; it is controlled by the other alignment parameters.)
-
-An unnamed bit-field will not affect the alignment of the containing
-structure.
-
-If the macro is defined, its definition should be a C expression;
-a nonzero value for the expression enables this behavior.
-
-Note that if this macro is not defined, or its value is zero, some
-bit-fields may cross more than one alignment boundary. The compiler can
-support such references if there are @samp{insv}, @samp{extv}, and
-@samp{extzv} insns that can directly reference memory.
-
-The other known way of making bit-fields work is to define
-@code{STRUCTURE_SIZE_BOUNDARY} as large as @code{BIGGEST_ALIGNMENT}.
-Then every structure can be accessed with fullwords.
-
-Unless the machine has bit-field instructions or you define
-@code{STRUCTURE_SIZE_BOUNDARY} that way, you must define
-@code{PCC_BITFIELD_TYPE_MATTERS} to have a nonzero value.
-
-If your aim is to make GCC use the same conventions for laying out
-bit-fields as are used by another compiler, here is how to investigate
-what the other compiler does. Compile and run this program:
-
-@smallexample
-struct foo1
-@{
- char x;
- char :0;
- char y;
-@};
-
-struct foo2
-@{
- char x;
- int :0;
- char y;
-@};
-
-main ()
-@{
- printf ("Size of foo1 is %d\n",
- sizeof (struct foo1));
- printf ("Size of foo2 is %d\n",
- sizeof (struct foo2));
- exit (0);
-@}
-@end smallexample
-
-If this prints 2 and 5, then the compiler's behavior is what you would
-get from @code{PCC_BITFIELD_TYPE_MATTERS}.
-@end defmac
-
-@defmac BITFIELD_NBYTES_LIMITED
-Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited
-to aligning a bit-field within the structure.
-@end defmac
-
-@hook TARGET_ALIGN_ANON_BITFIELD
-
-@hook TARGET_NARROW_VOLATILE_BITFIELD
-
-@hook TARGET_MEMBER_TYPE_FORCES_BLK
-
-@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
-Define this macro as an expression for the alignment of a type (given
-by @var{type} as a tree node) if the alignment computed in the usual
-way is @var{computed} and the alignment explicitly specified was
-@var{specified}.
-
-The default is to use @var{specified} if it is larger; otherwise, use
-the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT}
-@end defmac
-
-@defmac MAX_FIXED_MODE_SIZE
-An integer expression for the size in bits of the largest integer
-machine mode that should actually be used. All integer machine modes of
-this size or smaller can be used for structures and unions with the
-appropriate sizes. If this macro is undefined, @code{GET_MODE_BITSIZE
-(DImode)} is assumed.
-@end defmac
-
-@defmac STACK_SAVEAREA_MODE (@var{save_level})
-If defined, an expression of type @code{machine_mode} that
-specifies the mode of the save area operand of a
-@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
-@var{save_level} is one of @code{SAVE_BLOCK}, @code{SAVE_FUNCTION}, or
-@code{SAVE_NONLOCAL} and selects which of the three named patterns is
-having its mode specified.
-
-You need not define this macro if it always returns @code{Pmode}. You
-would most commonly define this macro if the
-@code{save_stack_@var{level}} patterns need to support both a 32- and a
-64-bit mode.
-@end defmac
-
-@defmac STACK_SIZE_MODE
-If defined, an expression of type @code{machine_mode} that
-specifies the mode of the size increment operand of an
-@code{allocate_stack} named pattern (@pxref{Standard Names}).
-
-You need not define this macro if it always returns @code{word_mode}.
-You would most commonly define this macro if the @code{allocate_stack}
-pattern needs to support both a 32- and a 64-bit mode.
-@end defmac
-
-@hook TARGET_LIBGCC_CMP_RETURN_MODE
-
-@hook TARGET_LIBGCC_SHIFT_COUNT_MODE
-
-@hook TARGET_UNWIND_WORD_MODE
-
-@hook TARGET_MS_BITFIELD_LAYOUT_P
-
-@hook TARGET_DECIMAL_FLOAT_SUPPORTED_P
-
-@hook TARGET_FIXED_POINT_SUPPORTED_P
-
-@hook TARGET_EXPAND_TO_RTL_HOOK
-
-@hook TARGET_INSTANTIATE_DECLS
-
-@hook TARGET_MANGLE_TYPE
-
-@node Type Layout
-@section Layout of Source Language Data Types
-
-These macros define the sizes and other characteristics of the standard
-basic data types used in programs being compiled. Unlike the macros in
-the previous section, these apply to specific features of C and related
-languages, rather than to fundamental aspects of storage layout.
-
-@defmac INT_TYPE_SIZE
-A C expression for the size in bits of the type @code{int} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac SHORT_TYPE_SIZE
-A C expression for the size in bits of the type @code{short} on the
-target machine. If you don't define this, the default is half a word.
-(If this would be less than one storage unit, it is rounded up to one
-unit.)
-@end defmac
-
-@defmac LONG_TYPE_SIZE
-A C expression for the size in bits of the type @code{long} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac ADA_LONG_TYPE_SIZE
-On some machines, the size used for the Ada equivalent of the type
-@code{long} by a native Ada compiler differs from that used by C@. In
-that situation, define this macro to be a C expression to be used for
-the size of that type. If you don't define this, the default is the
-value of @code{LONG_TYPE_SIZE}.
-@end defmac
-
-@defmac LONG_LONG_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long} on the
-target machine. If you don't define this, the default is two
-words. If you want to support GNU Ada on your machine, the value of this
-macro must be at least 64.
-@end defmac
-
-@defmac CHAR_TYPE_SIZE
-A C expression for the size in bits of the type @code{char} on the
-target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac BOOL_TYPE_SIZE
-A C expression for the size in bits of the C++ type @code{bool} and
-C99 type @code{_Bool} on the target machine. If you don't define
-this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}.
-@end defmac
-
-@defmac FLOAT_TYPE_SIZE
-A C expression for the size in bits of the type @code{float} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac DOUBLE_TYPE_SIZE
-A C expression for the size in bits of the type @code{double} on the
-target machine. If you don't define this, the default is two
-words.
-@end defmac
-
-@defmac LONG_DOUBLE_TYPE_SIZE
-A C expression for the size in bits of the type @code{long double} on
-the target machine. If you don't define this, the default is two
-words.
-@end defmac
-
-@defmac SHORT_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{short _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{_Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 2}.
-@end defmac
-
-@defmac LONG_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{long _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 4}.
-@end defmac
-
-@defmac LONG_LONG_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 8}.
-@end defmac
-
-@defmac SHORT_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{short _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 2}.
-@end defmac
-
-@defmac ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{_Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 4}.
-@end defmac
-
-@defmac LONG_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{long _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 8}.
-@end defmac
-
-@defmac LONG_LONG_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 16}.
-@end defmac
-
-@defmac LIBGCC2_GNU_PREFIX
-This macro corresponds to the @code{TARGET_LIBFUNC_GNU_PREFIX} target
-hook and should be defined if that hook is overriden to be true. It
-causes function names in libgcc to be changed to use a @code{__gnu_}
-prefix for their name rather than the default @code{__}. A port which
-uses this macro should also arrange to use @file{t-gnu-prefix} in
-the libgcc @file{config.host}.
-@end defmac
-
-@defmac WIDEST_HARDWARE_FP_SIZE
-A C expression for the size in bits of the widest floating-point format
-supported by the hardware. If you define this macro, you must specify a
-value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}.
-If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE}
-is the default.
-@end defmac
-
-@defmac DEFAULT_SIGNED_CHAR
-An expression whose value is 1 or 0, according to whether the type
-@code{char} should be signed or unsigned by default. The user can
-always override this default with the options @option{-fsigned-char}
-and @option{-funsigned-char}.
-@end defmac
-
-@hook TARGET_DEFAULT_SHORT_ENUMS
-
-@defmac SIZE_TYPE
-A C expression for a string describing the name of the data type to use
-for size values. The typedef name @code{size_t} is defined using the
-contents of the string.
-
-The string can contain more than one keyword. If so, separate them with
-spaces, and write first any length keyword, then @code{unsigned} if
-appropriate, and finally @code{int}. The string must exactly match one
-of the data type names defined in the function
-@code{c_common_nodes_and_builtins} in the file @file{c-family/c-common.cc}.
-You may not omit @code{int} or change the order---that would cause the
-compiler to crash on startup.
-
-If you don't define this macro, the default is @code{"long unsigned
-int"}.
-@end defmac
-
-@defmac SIZETYPE
-GCC defines internal types (@code{sizetype}, @code{ssizetype},
-@code{bitsizetype} and @code{sbitsizetype}) for expressions
-dealing with size. This macro is a C expression for a string describing
-the name of the data type from which the precision of @code{sizetype}
-is extracted.
-
-The string has the same restrictions as @code{SIZE_TYPE} string.
-
-If you don't define this macro, the default is @code{SIZE_TYPE}.
-@end defmac
-
-@defmac PTRDIFF_TYPE
-A C expression for a string describing the name of the data type to use
-for the result of subtracting two pointers. The typedef name
-@code{ptrdiff_t} is defined using the contents of the string. See
-@code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is @code{"long int"}.
-@end defmac
-
-@defmac WCHAR_TYPE
-A C expression for a string describing the name of the data type to use
-for wide characters. The typedef name @code{wchar_t} is defined using
-the contents of the string. See @code{SIZE_TYPE} above for more
-information.
-
-If you don't define this macro, the default is @code{"int"}.
-@end defmac
-
-@defmac WCHAR_TYPE_SIZE
-A C expression for the size in bits of the data type for wide
-characters. This is used in @code{cpp}, which cannot make use of
-@code{WCHAR_TYPE}.
-@end defmac
-
-@defmac WINT_TYPE
-A C expression for a string describing the name of the data type to
-use for wide characters passed to @code{printf} and returned from
-@code{getwc}. The typedef name @code{wint_t} is defined using the
-contents of the string. See @code{SIZE_TYPE} above for more
-information.
-
-If you don't define this macro, the default is @code{"unsigned int"}.
-@end defmac
-
-@defmac INTMAX_TYPE
-A C expression for a string describing the name of the data type that
-can represent any value of any standard or extended signed integer type.
-The typedef name @code{intmax_t} is defined using the contents of the
-string. See @code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is the first of
-@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as
-much precision as @code{long long int}.
-@end defmac
-
-@defmac UINTMAX_TYPE
-A C expression for a string describing the name of the data type that
-can represent any value of any standard or extended unsigned integer
-type. The typedef name @code{uintmax_t} is defined using the contents
-of the string. See @code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is the first of
-@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long
-unsigned int"} that has as much precision as @code{long long unsigned
-int}.
-@end defmac
-
-@defmac SIG_ATOMIC_TYPE
-@defmacx INT8_TYPE
-@defmacx INT16_TYPE
-@defmacx INT32_TYPE
-@defmacx INT64_TYPE
-@defmacx UINT8_TYPE
-@defmacx UINT16_TYPE
-@defmacx UINT32_TYPE
-@defmacx UINT64_TYPE
-@defmacx INT_LEAST8_TYPE
-@defmacx INT_LEAST16_TYPE
-@defmacx INT_LEAST32_TYPE
-@defmacx INT_LEAST64_TYPE
-@defmacx UINT_LEAST8_TYPE
-@defmacx UINT_LEAST16_TYPE
-@defmacx UINT_LEAST32_TYPE
-@defmacx UINT_LEAST64_TYPE
-@defmacx INT_FAST8_TYPE
-@defmacx INT_FAST16_TYPE
-@defmacx INT_FAST32_TYPE
-@defmacx INT_FAST64_TYPE
-@defmacx UINT_FAST8_TYPE
-@defmacx UINT_FAST16_TYPE
-@defmacx UINT_FAST32_TYPE
-@defmacx UINT_FAST64_TYPE
-@defmacx INTPTR_TYPE
-@defmacx UINTPTR_TYPE
-C expressions for the standard types @code{sig_atomic_t},
-@code{int8_t}, @code{int16_t}, @code{int32_t}, @code{int64_t},
-@code{uint8_t}, @code{uint16_t}, @code{uint32_t}, @code{uint64_t},
-@code{int_least8_t}, @code{int_least16_t}, @code{int_least32_t},
-@code{int_least64_t}, @code{uint_least8_t}, @code{uint_least16_t},
-@code{uint_least32_t}, @code{uint_least64_t}, @code{int_fast8_t},
-@code{int_fast16_t}, @code{int_fast32_t}, @code{int_fast64_t},
-@code{uint_fast8_t}, @code{uint_fast16_t}, @code{uint_fast32_t},
-@code{uint_fast64_t}, @code{intptr_t}, and @code{uintptr_t}. See
-@code{SIZE_TYPE} above for more information.
-
-If any of these macros evaluates to a null pointer, the corresponding
-type is not supported; if GCC is configured to provide
-@code{<stdint.h>} in such a case, the header provided may not conform
-to C99, depending on the type in question. The defaults for all of
-these macros are null pointers.
-@end defmac
-
-@defmac TARGET_PTRMEMFUNC_VBIT_LOCATION
-The C++ compiler represents a pointer-to-member-function with a struct
-that looks like:
-
-@smallexample
- struct @{
- union @{
- void (*fn)();
- ptrdiff_t vtable_index;
- @};
- ptrdiff_t delta;
- @};
-@end smallexample
-
-@noindent
-The C++ compiler must use one bit to indicate whether the function that
-will be called through a pointer-to-member-function is virtual.
-Normally, we assume that the low-order bit of a function pointer must
-always be zero. Then, by ensuring that the vtable_index is odd, we can
-distinguish which variant of the union is in use. But, on some
-platforms function pointers can be odd, and so this doesn't work. In
-that case, we use the low-order bit of the @code{delta} field, and shift
-the remainder of the @code{delta} field to the left.
-
-GCC will automatically make the right selection about where to store
-this bit using the @code{FUNCTION_BOUNDARY} setting for your platform.
-However, some platforms such as ARM/Thumb have @code{FUNCTION_BOUNDARY}
-set such that functions always start at even addresses, but the lowest
-bit of pointers to functions indicate whether the function at that
-address is in ARM or Thumb mode. If this is the case of your
-architecture, you should define this macro to
-@code{ptrmemfunc_vbit_in_delta}.
-
-In general, you should not have to define this macro. On architectures
-in which function addresses are always even, according to
-@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to
-@code{ptrmemfunc_vbit_in_pfn}.
-@end defmac
-
-@defmac TARGET_VTABLE_USES_DESCRIPTORS
-Normally, the C++ compiler uses function pointers in vtables. This
-macro allows the target to change to use ``function descriptors''
-instead. Function descriptors are found on targets for whom a
-function pointer is actually a small data structure. Normally the
-data structure consists of the actual code address plus a data
-pointer to which the function's data is relative.
-
-If vtables are used, the value of this macro should be the number
-of words that the function descriptor occupies.
-@end defmac
-
-@defmac TARGET_VTABLE_ENTRY_ALIGN
-By default, the vtable entries are void pointers, the so the alignment
-is the same as pointer alignment. The value of this macro specifies
-the alignment of the vtable entry in bits. It should be defined only
-when special alignment is necessary. */
-@end defmac
-
-@defmac TARGET_VTABLE_DATA_ENTRY_DISTANCE
-There are a few non-descriptor entries in the vtable at offsets below
-zero. If these entries must be padded (say, to preserve the alignment
-specified by @code{TARGET_VTABLE_ENTRY_ALIGN}), set this to the number
-of words in each data entry.
-@end defmac
-
-@node Registers
-@section Register Usage
-@cindex register usage
-
-This section explains how to describe what registers the target machine
-has, and how (in general) they can be used.
-
-The description of which registers a specific instruction can use is
-done with register classes; see @ref{Register Classes}. For information
-on using registers to access a stack frame, see @ref{Frame Registers}.
-For passing values in registers, see @ref{Register Arguments}.
-For returning values in registers, see @ref{Scalar Return}.
-
-@menu
-* Register Basics:: Number and kinds of registers.
-* Allocation Order:: Order in which registers are allocated.
-* Values in Registers:: What kinds of values each reg can hold.
-* Leaf Functions:: Renumbering registers for leaf functions.
-* Stack Registers:: Handling a register stack such as 80387.
-@end menu
-
-@node Register Basics
-@subsection Basic Characteristics of Registers
-
-@c prevent bad page break with this line
-Registers have various characteristics.
-
-@defmac FIRST_PSEUDO_REGISTER
-Number of hardware registers known to the compiler. They receive
-numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first
-pseudo register's number really is assigned the number
-@code{FIRST_PSEUDO_REGISTER}.
-@end defmac
-
-@defmac FIXED_REGISTERS
-@cindex fixed register
-An initializer that says which registers are used for fixed purposes
-all throughout the compiled code and are therefore not available for
-general allocation. These would include the stack pointer, the frame
-pointer (except on machines where that can be used as a general
-register when no frame pointer is needed), the program counter on
-machines where that is considered one of the addressable registers,
-and any other numbered register with a standard use.
-
-This information is expressed as a sequence of numbers, separated by
-commas and surrounded by braces. The @var{n}th number is 1 if
-register @var{n} is fixed, 0 otherwise.
-
-The table initialized from this macro, and the table initialized by
-the following one, may be overridden at run time either automatically,
-by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by
-the user with the command options @option{-ffixed-@var{reg}},
-@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}.
-@end defmac
-
-@defmac CALL_USED_REGISTERS
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-Like @code{FIXED_REGISTERS} but has 1 for each register that is
-clobbered (in general) by function calls as well as for fixed
-registers. This macro therefore identifies the registers that are not
-available for general allocation of values that must live across
-function calls.
-
-If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler
-automatically saves it on function entry and restores it on function
-exit, if the register is used within the function.
-
-Exactly one of @code{CALL_USED_REGISTERS} and @code{CALL_REALLY_USED_REGISTERS}
-must be defined. Modern ports should define @code{CALL_REALLY_USED_REGISTERS}.
-@end defmac
-
-@defmac CALL_REALLY_USED_REGISTERS
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-Like @code{CALL_USED_REGISTERS} except this macro doesn't require
-that the entire set of @code{FIXED_REGISTERS} be included.
-(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
-
-Exactly one of @code{CALL_USED_REGISTERS} and @code{CALL_REALLY_USED_REGISTERS}
-must be defined. Modern ports should define @code{CALL_REALLY_USED_REGISTERS}.
-@end defmac
-
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-@hook TARGET_FNTYPE_ABI
-
-@hook TARGET_INSN_CALLEE_ABI
-
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-@hook TARGET_HARD_REGNO_CALL_PART_CLOBBERED
-
-@hook TARGET_GET_MULTILIB_ABI_NAME
-
-@findex fixed_regs
-@findex call_used_regs
-@findex global_regs
-@findex reg_names
-@findex reg_class_contents
-@hook TARGET_CONDITIONAL_REGISTER_USAGE
-
-@defmac INCOMING_REGNO (@var{out})
-Define this macro if the target machine has register windows. This C
-expression returns the register number as seen by the called function
-corresponding to the register number @var{out} as seen by the calling
-function. Return @var{out} if register number @var{out} is not an
-outbound register.
-@end defmac
-
-@defmac OUTGOING_REGNO (@var{in})
-Define this macro if the target machine has register windows. This C
-expression returns the register number as seen by the calling function
-corresponding to the register number @var{in} as seen by the called
-function. Return @var{in} if register number @var{in} is not an inbound
-register.
-@end defmac
-
-@defmac LOCAL_REGNO (@var{regno})
-Define this macro if the target machine has register windows. This C
-expression returns true if the register is call-saved but is in the
-register window. Unlike most call-saved registers, such registers
-need not be explicitly restored on function exit or during non-local
-gotos.
-@end defmac
-
-@defmac PC_REGNUM
-If the program counter has a register number, define this as that
-register number. Otherwise, do not define it.
-@end defmac
-
-@node Allocation Order
-@subsection Order of Allocation of Registers
-@cindex order of register allocation
-@cindex register allocation order
-
-@c prevent bad page break with this line
-Registers are allocated in order.
-
-@defmac REG_ALLOC_ORDER
-If defined, an initializer for a vector of integers, containing the
-numbers of hard registers in the order in which GCC should prefer
-to use them (from most preferred to least).
-
-If this macro is not defined, registers are used lowest numbered first
-(all else being equal).
-
-One use of this macro is on machines where the highest numbered
-registers must always be saved and the save-multiple-registers
-instruction supports only sequences of consecutive registers. On such
-machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists
-the highest numbered allocable register first.
-@end defmac
-
-@defmac ADJUST_REG_ALLOC_ORDER
-A C statement (sans semicolon) to choose the order in which to allocate
-hard registers for pseudo-registers local to a basic block.
-
-Store the desired register order in the array @code{reg_alloc_order}.
-Element 0 should be the register to allocate first; element 1, the next
-register; and so on.
-
-The macro body should not assume anything about the contents of
-@code{reg_alloc_order} before execution of the macro.
-
-On most machines, it is not necessary to define this macro.
-@end defmac
-
-@defmac HONOR_REG_ALLOC_ORDER
-Normally, IRA tries to estimate the costs for saving a register in the
-prologue and restoring it in the epilogue. This discourages it from
-using call-saved registers. If a machine wants to ensure that IRA
-allocates registers in the order given by REG_ALLOC_ORDER even if some
-call-saved registers appear earlier than call-used ones, then define this
-macro as a C expression to nonzero. Default is 0.
-@end defmac
-
-@defmac IRA_HARD_REGNO_ADD_COST_MULTIPLIER (@var{regno})
-In some case register allocation order is not enough for the
-Integrated Register Allocator (@acronym{IRA}) to generate a good code.
-If this macro is defined, it should return a floating point value
-based on @var{regno}. The cost of using @var{regno} for a pseudo will
-be increased by approximately the pseudo's usage frequency times the
-value returned by this macro. Not defining this macro is equivalent
-to having it always return @code{0.0}.
-
-On most machines, it is not necessary to define this macro.
-@end defmac
-
-@node Values in Registers
-@subsection How Values Fit in Registers
-
-This section discusses the macros that describe which kinds of values
-(specifically, which machine modes) each register can hold, and how many
-consecutive registers are needed for a given mode.
-
-@hook TARGET_HARD_REGNO_NREGS
-
-@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode})
-A C expression that is nonzero if a value of mode @var{mode}, stored
-in memory, ends with padding that causes it to take up more space than
-in registers starting at register number @var{regno} (as determined by
-multiplying GCC's notion of the size of the register when containing
-this mode by the number of registers returned by
-@code{TARGET_HARD_REGNO_NREGS}). By default this is zero.
-
-For example, if a floating-point value is stored in three 32-bit
-registers but takes up 128 bits in memory, then this would be
-nonzero.
-
-This macros only needs to be defined if there are cases where
-@code{subreg_get_info}
-would otherwise wrongly determine that a @code{subreg} can be
-represented by an offset to the register number, when in fact such a
-@code{subreg} would contain some of the padding not stored in
-registers and so not be representable.
-@end defmac
-
-@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode})
-For values of @var{regno} and @var{mode} for which
-@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression
-returning the greater number of registers required to hold the value
-including any padding. In the example above, the value would be four.
-@end defmac
-
-@defmac REGMODE_NATURAL_SIZE (@var{mode})
-Define this macro if the natural size of registers that hold values
-of mode @var{mode} is not the word size. It is a C expression that
-should give the natural size in bytes for the specified mode. It is
-used by the register allocator to try to optimize its results. This
-happens for example on SPARC 64-bit where the natural size of
-floating-point registers is still 32-bit.
-@end defmac
-
-@hook TARGET_HARD_REGNO_MODE_OK
-
-@defmac HARD_REGNO_RENAME_OK (@var{from}, @var{to})
-A C expression that is nonzero if it is OK to rename a hard register
-@var{from} to another hard register @var{to}.
-
-One common use of this macro is to prevent renaming of a register to
-another register that is not saved by a prologue in an interrupt
-handler.
-
-The default is always nonzero.
-@end defmac
-
-@hook TARGET_MODES_TIEABLE_P
-
-@hook TARGET_HARD_REGNO_SCRATCH_OK
-
-@defmac AVOID_CCMODE_COPIES
-Define this macro if the compiler should avoid copies to/from @code{CCmode}
-registers. You should only define this macro if support for copying to/from
-@code{CCmode} is incomplete.
-@end defmac
-
-@node Leaf Functions
-@subsection Handling Leaf Functions
-
-@cindex leaf functions
-@cindex functions, leaf
-On some machines, a leaf function (i.e., one which makes no calls) can run
-more efficiently if it does not make its own register window. Often this
-means it is required to receive its arguments in the registers where they
-are passed by the caller, instead of the registers where they would
-normally arrive.
-
-The special treatment for leaf functions generally applies only when
-other conditions are met; for example, often they may use only those
-registers for its own variables and temporaries. We use the term ``leaf
-function'' to mean a function that is suitable for this special
-handling, so that functions with no calls are not necessarily ``leaf
-functions''.
-
-GCC assigns register numbers before it knows whether the function is
-suitable for leaf function treatment. So it needs to renumber the
-registers in order to output a leaf function. The following macros
-accomplish this.
-
-@defmac LEAF_REGISTERS
-Name of a char vector, indexed by hard register number, which
-contains 1 for a register that is allowable in a candidate for leaf
-function treatment.
-
-If leaf function treatment involves renumbering the registers, then the
-registers marked here should be the ones before renumbering---those that
-GCC would ordinarily allocate. The registers which will actually be
-used in the assembler code, after renumbering, should not be marked with 1
-in this vector.
-
-Define this macro only if the target machine offers a way to optimize
-the treatment of leaf functions.
-@end defmac
-
-@defmac LEAF_REG_REMAP (@var{regno})
-A C expression whose value is the register number to which @var{regno}
-should be renumbered, when a function is treated as a leaf function.
-
-If @var{regno} is a register number which should not appear in a leaf
-function before renumbering, then the expression should yield @minus{}1, which
-will cause the compiler to abort.
-
-Define this macro only if the target machine offers a way to optimize the
-treatment of leaf functions, and registers need to be renumbered to do
-this.
-@end defmac
-
-@findex current_function_is_leaf
-@findex current_function_uses_only_leaf_regs
-@code{TARGET_ASM_FUNCTION_PROLOGUE} and
-@code{TARGET_ASM_FUNCTION_EPILOGUE} must usually treat leaf functions
-specially. They can test the C variable @code{current_function_is_leaf}
-which is nonzero for leaf functions. @code{current_function_is_leaf} is
-set prior to local register allocation and is valid for the remaining
-compiler passes. They can also test the C variable
-@code{current_function_uses_only_leaf_regs} which is nonzero for leaf
-functions which only use leaf registers.
-@code{current_function_uses_only_leaf_regs} is valid after all passes
-that modify the instructions have been run and is only useful if
-@code{LEAF_REGISTERS} is defined.
-@c changed this to fix overfull. ALSO: why the "it" at the beginning
-@c of the next paragraph?! --mew 2feb93
-
-@node Stack Registers
-@subsection Registers That Form a Stack
-
-There are special features to handle computers where some of the
-``registers'' form a stack. Stack registers are normally written by
-pushing onto the stack, and are numbered relative to the top of the
-stack.
-
-Currently, GCC can only handle one group of stack-like registers, and
-they must be consecutively numbered. Furthermore, the existing
-support for stack-like registers is specific to the 80387 floating
-point coprocessor. If you have a new architecture that uses
-stack-like registers, you will need to do substantial work on
-@file{reg-stack.cc} and write your machine description to cooperate
-with it, as well as defining these macros.
-
-@defmac STACK_REGS
-Define this if the machine has any stack-like registers.
-@end defmac
-
-@defmac STACK_REG_COVER_CLASS
-This is a cover class containing the stack registers. Define this if
-the machine has any stack-like registers.
-@end defmac
-
-@defmac FIRST_STACK_REG
-The number of the first stack-like register. This one is the top
-of the stack.
-@end defmac
-
-@defmac LAST_STACK_REG
-The number of the last stack-like register. This one is the bottom of
-the stack.
-@end defmac
-
-@node Register Classes
-@section Register Classes
-@cindex register class definitions
-@cindex class definitions, register
-
-On many machines, the numbered registers are not all equivalent.
-For example, certain registers may not be allowed for indexed addressing;
-certain registers may not be allowed in some instructions. These machine
-restrictions are described to the compiler using @dfn{register classes}.
-
-You define a number of register classes, giving each one a name and saying
-which of the registers belong to it. Then you can specify register classes
-that are allowed as operands to particular instruction patterns.
-
-@findex ALL_REGS
-@findex NO_REGS
-In general, each register will belong to several classes. In fact, one
-class must be named @code{ALL_REGS} and contain all the registers. Another
-class must be named @code{NO_REGS} and contain no registers. Often the
-union of two classes will be another class; however, this is not required.
-
-@findex GENERAL_REGS
-One of the classes must be named @code{GENERAL_REGS}. There is nothing
-terribly special about the name, but the operand constraint letters
-@samp{r} and @samp{g} specify this class. If @code{GENERAL_REGS} is
-the same as @code{ALL_REGS}, just define it as a macro which expands
-to @code{ALL_REGS}.
-
-Order the classes so that if class @var{x} is contained in class @var{y}
-then @var{x} has a lower class number than @var{y}.
-
-The way classes other than @code{GENERAL_REGS} are specified in operand
-constraints is through machine-dependent operand constraint letters.
-You can define such letters to correspond to various classes, then use
-them in operand constraints.
-
-You must define the narrowest register classes for allocatable
-registers, so that each class either has no subclasses, or that for
-some mode, the move cost between registers within the class is
-cheaper than moving a register in the class to or from memory
-(@pxref{Costs}).
-
-You should define a class for the union of two classes whenever some
-instruction allows both classes. For example, if an instruction allows
-either a floating point (coprocessor) register or a general register for a
-certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS}
-which includes both of them. Otherwise you will get suboptimal code,
-or even internal compiler errors when reload cannot find a register in the
-class computed via @code{reg_class_subunion}.
-
-You must also specify certain redundant information about the register
-classes: for each class, which classes contain it and which ones are
-contained in it; for each pair of classes, the largest class contained
-in their union.
-
-When a value occupying several consecutive registers is expected in a
-certain class, all the registers used must belong to that class.
-Therefore, register classes cannot be used to enforce a requirement for
-a register pair to start with an even-numbered register. The way to
-specify this requirement is with @code{TARGET_HARD_REGNO_MODE_OK}.
-
-Register classes used for input-operands of bitwise-and or shift
-instructions have a special requirement: each such class must have, for
-each fixed-point machine mode, a subclass whose registers can transfer that
-mode to or from memory. For example, on some machines, the operations for
-single-byte values (@code{QImode}) are limited to certain registers. When
-this is so, each register class that is used in a bitwise-and or shift
-instruction must have a subclass consisting of registers from which
-single-byte values can be loaded or stored. This is so that
-@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return.
-
-@deftp {Data type} {enum reg_class}
-An enumerated type that must be defined with all the register class names
-as enumerated values. @code{NO_REGS} must be first. @code{ALL_REGS}
-must be the last register class, followed by one more enumerated value,
-@code{LIM_REG_CLASSES}, which is not a register class but rather
-tells how many classes there are.
-
-Each register class has a number, which is the value of casting
-the class name to type @code{int}. The number serves as an index
-in many of the tables described below.
-@end deftp
-
-@defmac N_REG_CLASSES
-The number of distinct register classes, defined as follows:
-
-@smallexample
-#define N_REG_CLASSES (int) LIM_REG_CLASSES
-@end smallexample
-@end defmac
-
-@defmac REG_CLASS_NAMES
-An initializer containing the names of the register classes as C string
-constants. These names are used in writing some of the debugging dumps.
-@end defmac
-
-@defmac REG_CLASS_CONTENTS
-An initializer containing the contents of the register classes, as integers
-which are bit masks. The @var{n}th integer specifies the contents of class
-@var{n}. The way the integer @var{mask} is interpreted is that
-register @var{r} is in the class if @code{@var{mask} & (1 << @var{r})} is 1.
-
-When the machine has more than 32 registers, an integer does not suffice.
-Then the integers are replaced by sub-initializers, braced groupings containing
-several integers. Each sub-initializer must be suitable as an initializer
-for the type @code{HARD_REG_SET} which is defined in @file{hard-reg-set.h}.
-In this situation, the first integer in each sub-initializer corresponds to
-registers 0 through 31, the second integer to registers 32 through 63, and
-so on.
-@end defmac
-
-@defmac REGNO_REG_CLASS (@var{regno})
-A C expression whose value is a register class containing hard register
-@var{regno}. In general there is more than one such class; choose a class
-which is @dfn{minimal}, meaning that no smaller class also contains the
-register.
-@end defmac
-
-@defmac BASE_REG_CLASS
-A macro whose definition is the name of the class to which a valid
-base register must belong. A base register is one used in an address
-which is the register value plus a displacement.
-@end defmac
-
-@defmac MODE_BASE_REG_CLASS (@var{mode})
-This is a variation of the @code{BASE_REG_CLASS} macro which allows
-the selection of a base register in a mode dependent manner. If
-@var{mode} is VOIDmode then it should return the same value as
-@code{BASE_REG_CLASS}.
-@end defmac
-
-@defmac MODE_BASE_REG_REG_CLASS (@var{mode})
-A C expression whose value is the register class to which a valid
-base register must belong in order to be used in a base plus index
-register address. You should define this macro if base plus index
-addresses have different requirements than other base register uses.
-@end defmac
-
-@defmac MODE_CODE_BASE_REG_CLASS (@var{mode}, @var{address_space}, @var{outer_code}, @var{index_code})
-A C expression whose value is the register class to which a valid
-base register for a memory reference in mode @var{mode} to address
-space @var{address_space} must belong. @var{outer_code} and @var{index_code}
-define the context in which the base register occurs. @var{outer_code} is
-the code of the immediately enclosing expression (@code{MEM} for the top level
-of an address, @code{ADDRESS} for something that occurs in an
-@code{address_operand}). @var{index_code} is the code of the corresponding
-index expression if @var{outer_code} is @code{PLUS}; @code{SCRATCH} otherwise.
-@end defmac
-
-@defmac INDEX_REG_CLASS
-A macro whose definition is the name of the class to which a valid
-index register must belong. An index register is one used in an
-address where its value is either multiplied by a scale factor or
-added to another register (as well as added to a displacement).
-@end defmac
-
-@defmac REGNO_OK_FOR_BASE_P (@var{num})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as a base register in operand addresses.
-@end defmac
-
-@defmac REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
-A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that
-that expression may examine the mode of the memory reference in
-@var{mode}. You should define this macro if the mode of the memory
-reference affects whether a register may be used as a base register. If
-you define this macro, the compiler will use it instead of
-@code{REGNO_OK_FOR_BASE_P}. The mode may be @code{VOIDmode} for
-addresses that appear outside a @code{MEM}, i.e., as an
-@code{address_operand}.
-@end defmac
-
-@defmac REGNO_MODE_OK_FOR_REG_BASE_P (@var{num}, @var{mode})
-A C expression which is nonzero if register number @var{num} is suitable for
-use as a base register in base plus index operand addresses, accessing
-memory in mode @var{mode}. It may be either a suitable hard register or a
-pseudo register that has been allocated such a hard register. You should
-define this macro if base plus index addresses have different requirements
-than other base register uses.
-
-Use of this macro is deprecated; please use the more general
-@code{REGNO_MODE_CODE_OK_FOR_BASE_P}.
-@end defmac
-
-@defmac REGNO_MODE_CODE_OK_FOR_BASE_P (@var{num}, @var{mode}, @var{address_space}, @var{outer_code}, @var{index_code})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as a base register in operand addresses, accessing
-memory in mode @var{mode} in address space @var{address_space}.
-This is similar to @code{REGNO_MODE_OK_FOR_BASE_P}, except
-that that expression may examine the context in which the register
-appears in the memory reference. @var{outer_code} is the code of the
-immediately enclosing expression (@code{MEM} if at the top level of the
-address, @code{ADDRESS} for something that occurs in an
-@code{address_operand}). @var{index_code} is the code of the
-corresponding index expression if @var{outer_code} is @code{PLUS};
-@code{SCRATCH} otherwise. The mode may be @code{VOIDmode} for addresses
-that appear outside a @code{MEM}, i.e., as an @code{address_operand}.
-@end defmac
-
-@defmac REGNO_OK_FOR_INDEX_P (@var{num})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as an index register in operand addresses. It may be
-either a suitable hard register or a pseudo register that has been
-allocated such a hard register.
-
-The difference between an index register and a base register is that
-the index register may be scaled. If an address involves the sum of
-two registers, neither one of them scaled, then either one may be
-labeled the ``base'' and the other the ``index''; but whichever
-labeling is used must fit the machine's constraints of which registers
-may serve in each capacity. The compiler will try both labelings,
-looking for one that is valid, and will reload one or both registers
-only if neither labeling works.
-@end defmac
-
-@hook TARGET_PREFERRED_RENAME_CLASS
-
-@hook TARGET_PREFERRED_RELOAD_CLASS
-
-@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
-A C expression that places additional restrictions on the register class
-to use when it is necessary to copy value @var{x} into a register in class
-@var{class}. The value is a register class; perhaps @var{class}, or perhaps
-another, smaller class. On many machines, the following definition is
-safe:
-
-@smallexample
-#define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS
-@end smallexample
-
-Sometimes returning a more restrictive class makes better code. For
-example, on the 68000, when @var{x} is an integer constant that is in range
-for a @samp{moveq} instruction, the value of this macro is always
-@code{DATA_REGS} as long as @var{class} includes the data registers.
-Requiring a data register guarantees that a @samp{moveq} will be used.
-
-One case where @code{PREFERRED_RELOAD_CLASS} must not return
-@var{class} is if @var{x} is a legitimate constant which cannot be
-loaded into some register class. By returning @code{NO_REGS} you can
-force @var{x} into a memory location. For example, rs6000 can load
-immediate values into general-purpose registers, but does not have an
-instruction for loading an immediate value into a floating-point
-register, so @code{PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when
-@var{x} is a floating-point constant. If the constant cannot be loaded
-into any kind of register, code generation will be better if
-@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead
-of using @code{TARGET_PREFERRED_RELOAD_CLASS}.
-
-If an insn has pseudos in it after register allocation, reload will go
-through the alternatives and call repeatedly @code{PREFERRED_RELOAD_CLASS}
-to find the best one. Returning @code{NO_REGS}, in this case, makes
-reload add a @code{!} in front of the constraint: the x86 back-end uses
-this feature to discourage usage of 387 registers when math is done in
-the SSE registers (and vice versa).
-@end defmac
-
-@hook TARGET_PREFERRED_OUTPUT_RELOAD_CLASS
-
-@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
-A C expression that places additional restrictions on the register class
-to use when it is necessary to be able to hold a value of mode
-@var{mode} in a reload register for which class @var{class} would
-ordinarily be used.
-
-Unlike @code{PREFERRED_RELOAD_CLASS}, this macro should be used when
-there are certain modes that simply cannot go in certain reload classes.
-
-The value is a register class; perhaps @var{class}, or perhaps another,
-smaller class.
-
-Don't define this macro unless the target machine has limitations which
-require the macro to do something nontrivial.
-@end defmac
-
-@hook TARGET_SECONDARY_RELOAD
-
-@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_SECONDARY_RELOAD} instead.
-
-These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD}
-target hook. Older ports still define these macros to indicate to the
-reload phase that it may
-need to allocate at least one register for a reload in addition to the
-register to contain the data. Specifically, if copying @var{x} to a
-register @var{class} in @var{mode} requires an intermediate register,
-you were supposed to define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
-largest register class all of whose registers can be used as
-intermediate registers or scratch registers.
-
-If copying a register @var{class} in @var{mode} to @var{x} requires an
-intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS}
-was supposed to be defined to return the largest register
-class required. If the
-requirements for input and output reloads were the same, the macro
-@code{SECONDARY_RELOAD_CLASS} should have been used instead of defining both
-macros identically.
-
-The values returned by these macros are often @code{GENERAL_REGS}.
-Return @code{NO_REGS} if no spare register is needed; i.e., if @var{x}
-can be directly copied to or from a register of @var{class} in
-@var{mode} without requiring a scratch register. Do not define this
-macro if it would always return @code{NO_REGS}.
-
-If a scratch register is required (either with or without an
-intermediate register), you were supposed to define patterns for
-@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required
-(@pxref{Standard Names}. These patterns, which were normally
-implemented with a @code{define_expand}, should be similar to the
-@samp{mov@var{m}} patterns, except that operand 2 is the scratch
-register.
-
-These patterns need constraints for the reload register and scratch
-register that
-contain a single register class. If the original reload register (whose
-class is @var{class}) can meet the constraint given in the pattern, the
-value returned by these macros is used for the class of the scratch
-register. Otherwise, two additional reload registers are required.
-Their classes are obtained from the constraints in the insn pattern.
-
-@var{x} might be a pseudo-register or a @code{subreg} of a
-pseudo-register, which could either be in a hard register or in memory.
-Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is
-in memory and the hard register number if it is in a register.
-
-These macros should not be used in the case where a particular class of
-registers can only be copied to memory and not to another class of
-registers. In that case, secondary reload registers are not needed and
-would not be helpful. Instead, a stack location must be used to perform
-the copy and the @code{mov@var{m}} pattern should use memory as an
-intermediate storage. This case often occurs between floating-point and
-general registers.
-@end defmac
-
-@hook TARGET_SECONDARY_MEMORY_NEEDED
-
-@defmac SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
-Normally when @code{TARGET_SECONDARY_MEMORY_NEEDED} is defined, the compiler
-allocates a stack slot for a memory location needed for register copies.
-If this macro is defined, the compiler instead uses the memory location
-defined by this macro.
-
-Do not define this macro if you do not define
-@code{TARGET_SECONDARY_MEMORY_NEEDED}.
-@end defmac
-
-@hook TARGET_SECONDARY_MEMORY_NEEDED_MODE
-
-@hook TARGET_SELECT_EARLY_REMAT_MODES
-
-@hook TARGET_CLASS_LIKELY_SPILLED_P
-
-@hook TARGET_CLASS_MAX_NREGS
-
-@defmac CLASS_MAX_NREGS (@var{class}, @var{mode})
-A C expression for the maximum number of consecutive registers
-of class @var{class} needed to hold a value of mode @var{mode}.
-
-This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}. In fact,
-the value of the macro @code{CLASS_MAX_NREGS (@var{class}, @var{mode})}
-should be the maximum value of @code{TARGET_HARD_REGNO_NREGS (@var{regno},
-@var{mode})} for all @var{regno} values in the class @var{class}.
-
-This macro helps control the handling of multiple-word values
-in the reload pass.
-@end defmac
-
-@hook TARGET_CAN_CHANGE_MODE_CLASS
-
-@hook TARGET_IRA_CHANGE_PSEUDO_ALLOCNO_CLASS
-
-@hook TARGET_LRA_P
-
-@hook TARGET_REGISTER_PRIORITY
-
-@hook TARGET_REGISTER_USAGE_LEVELING_P
-
-@hook TARGET_DIFFERENT_ADDR_DISPLACEMENT_P
-
-@hook TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P
-
-@hook TARGET_LEGITIMIZE_ADDRESS_DISPLACEMENT
-
-@hook TARGET_SPILL_CLASS
-
-@hook TARGET_ADDITIONAL_ALLOCNO_CLASS_P
-
-@hook TARGET_CSTORE_MODE
-
-@hook TARGET_COMPUTE_PRESSURE_CLASSES
-
-@node Stack and Calling
-@section Stack Layout and Calling Conventions
-@cindex calling conventions
-
-@c prevent bad page break with this line
-This describes the stack layout and calling conventions.
-
-@menu
-* Frame Layout::
-* Exception Handling::
-* Stack Checking::
-* Frame Registers::
-* Elimination::
-* Stack Arguments::
-* Register Arguments::
-* Scalar Return::
-* Aggregate Return::
-* Caller Saves::
-* Function Entry::
-* Profiling::
-* Tail Calls::
-* Shrink-wrapping separate components::
-* Stack Smashing Protection::
-* Miscellaneous Register Hooks::
-@end menu
-
-@node Frame Layout
-@subsection Basic Stack Layout
-@cindex stack frame layout
-@cindex frame layout
-
-@c prevent bad page break with this line
-Here is the basic stack layout.
-
-@defmac STACK_GROWS_DOWNWARD
-Define this macro to be true if pushing a word onto the stack moves the stack
-pointer to a smaller address, and false otherwise.
-@end defmac
-
-@defmac STACK_PUSH_CODE
-This macro defines the operation used when something is pushed
-on the stack. In RTL, a push operation will be
-@code{(set (mem (STACK_PUSH_CODE (reg sp))) @dots{})}
-
-The choices are @code{PRE_DEC}, @code{POST_DEC}, @code{PRE_INC},
-and @code{POST_INC}. Which of these is correct depends on
-the stack direction and on whether the stack pointer points
-to the last item on the stack or whether it points to the
-space for the next item on the stack.
-
-The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
-true, which is almost always right, and @code{PRE_INC} otherwise,
-which is often wrong.
-@end defmac
-
-@defmac FRAME_GROWS_DOWNWARD
-Define this macro to nonzero value if the addresses of local variable slots
-are at negative offsets from the frame pointer.
-@end defmac
-
-@defmac ARGS_GROW_DOWNWARD
-Define this macro if successive arguments to a function occupy decreasing
-addresses on the stack.
-@end defmac
-
-@hook TARGET_STARTING_FRAME_OFFSET
-
-@defmac STACK_ALIGNMENT_NEEDED
-Define to zero to disable final alignment of the stack during reload.
-The nonzero default for this macro is suitable for most ports.
-
-On ports where @code{TARGET_STARTING_FRAME_OFFSET} is nonzero or where there
-is a register save block following the local block that doesn't require
-alignment to @code{STACK_BOUNDARY}, it may be beneficial to disable
-stack alignment and do it in the backend.
-@end defmac
-
-@defmac STACK_POINTER_OFFSET
-Offset from the stack pointer register to the first location at which
-outgoing arguments are placed. If not specified, the default value of
-zero is used. This is the proper value for most machines.
-
-If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
-the first location at which outgoing arguments are placed.
-@end defmac
-
-@defmac FIRST_PARM_OFFSET (@var{fundecl})
-Offset from the argument pointer register to the first argument's
-address. On some machines it may depend on the data type of the
-function.
-
-If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
-the first argument's address.
-@end defmac
-
-@defmac STACK_DYNAMIC_OFFSET (@var{fundecl})
-Offset from the stack pointer register to an item dynamically allocated
-on the stack, e.g., by @code{alloca}.
-
-The default value for this macro is @code{STACK_POINTER_OFFSET} plus the
-length of the outgoing arguments. The default is correct for most
-machines. See @file{function.cc} for details.
-@end defmac
-
-@defmac INITIAL_FRAME_ADDRESS_RTX
-A C expression whose value is RTL representing the address of the initial
-stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
-@code{DYNAMIC_CHAIN_ADDRESS}. If you don't define this macro, a reasonable
-default value will be used. Define this macro in order to make frame pointer
-elimination work in the presence of @code{__builtin_frame_address (count)} and
-@code{__builtin_return_address (count)} for @code{count} not equal to zero.
-@end defmac
-
-@defmac DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
-A C expression whose value is RTL representing the address in a stack
-frame where the pointer to the caller's frame is stored. Assume that
-@var{frameaddr} is an RTL expression for the address of the stack frame
-itself.
-
-If you don't define this macro, the default is to return the value
-of @var{frameaddr}---that is, the stack frame address is also the
-address of the stack word that points to the previous frame.
-@end defmac
-
-@defmac SETUP_FRAME_ADDRESSES
-A C expression that produces the machine-specific code to
-setup the stack so that arbitrary frames can be accessed. For example,
-on the SPARC, we must flush all of the register windows to the stack
-before we can access arbitrary stack frames. You will seldom need to
-define this macro. The default is to do nothing.
-@end defmac
-
-@hook TARGET_BUILTIN_SETJMP_FRAME_VALUE
-
-@defmac FRAME_ADDR_RTX (@var{frameaddr})
-A C expression whose value is RTL representing the value of the frame
-address for the current frame. @var{frameaddr} is the frame pointer
-of the current frame. This is used for __builtin_frame_address.
-You need only define this macro if the frame address is not the same
-as the frame pointer. Most machines do not need to define it.
-@end defmac
-
-@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
-A C expression whose value is RTL representing the value of the return
-address for the frame @var{count} steps up from the current frame, after
-the prologue. @var{frameaddr} is the frame pointer of the @var{count}
-frame, or the frame pointer of the @var{count} @minus{} 1 frame if
-@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is nonzero.
-
-The value of the expression must always be the correct address when
-@var{count} is zero, but may be @code{NULL_RTX} if there is no way to
-determine the return address of other frames.
-@end defmac
-
-@defmac RETURN_ADDR_IN_PREVIOUS_FRAME
-Define this macro to nonzero value if the return address of a particular
-stack frame is accessed from the frame pointer of the previous stack
-frame. The zero default for this macro is suitable for most ports.
-@end defmac
-
-@defmac INCOMING_RETURN_ADDR_RTX
-A C expression whose value is RTL representing the location of the
-incoming return address at the beginning of any function, before the
-prologue. This RTL is either a @code{REG}, indicating that the return
-value is saved in @samp{REG}, or a @code{MEM} representing a location in
-the stack.
-
-You only need to define this macro if you want to support call frame
-debugging information like that provided by DWARF 2.
-
-If this RTL is a @code{REG}, you should also define
-@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}.
-@end defmac
-
-@defmac DWARF_ALT_FRAME_RETURN_COLUMN
-A C expression whose value is an integer giving a DWARF 2 column
-number that may be used as an alternative return column. The column
-must not correspond to any gcc hard register (that is, it must not
-be in the range of @code{DWARF_FRAME_REGNUM}).
-
-This macro can be useful if @code{DWARF_FRAME_RETURN_COLUMN} is set to a
-general register, but an alternative column needs to be used for signal
-frames. Some targets have also used different frame return columns
-over time.
-@end defmac
-
-@defmac DWARF_ZERO_REG
-A C expression whose value is an integer giving a DWARF 2 register
-number that is considered to always have the value zero. This should
-only be defined if the target has an architected zero register, and
-someone decided it was a good idea to use that register number to
-terminate the stack backtrace. New ports should avoid this.
-@end defmac
-
-@hook TARGET_DWARF_HANDLE_FRAME_UNSPEC
-
-@hook TARGET_DWARF_POLY_INDETERMINATE_VALUE
-
-@defmac INCOMING_FRAME_SP_OFFSET
-A C expression whose value is an integer giving the offset, in bytes,
-from the value of the stack pointer register to the top of the stack
-frame at the beginning of any function, before the prologue. The top of
-the frame is defined to be the value of the stack pointer in the
-previous frame, just before the call instruction.
-
-You only need to define this macro if you want to support call frame
-debugging information like that provided by DWARF 2.
-@end defmac
-
-@defmac DEFAULT_INCOMING_FRAME_SP_OFFSET
-Like @code{INCOMING_FRAME_SP_OFFSET}, but must be the same for all
-functions of the same ABI, and when using GAS @code{.cfi_*} directives
-must also agree with the default CFI GAS emits. Define this macro
-only if @code{INCOMING_FRAME_SP_OFFSET} can have different values
-between different functions of the same ABI or when
-@code{INCOMING_FRAME_SP_OFFSET} does not agree with GAS default CFI.
-@end defmac
-
-@defmac ARG_POINTER_CFA_OFFSET (@var{fundecl})
-A C expression whose value is an integer giving the offset, in bytes,
-from the argument pointer to the canonical frame address (cfa). The
-final value should coincide with that calculated by
-@code{INCOMING_FRAME_SP_OFFSET}. Which is unfortunately not usable
-during virtual register instantiation.
-
-The default value for this macro is
-@code{FIRST_PARM_OFFSET (fundecl) + crtl->args.pretend_args_size},
-which is correct for most machines; in general, the arguments are found
-immediately before the stack frame. Note that this is not the case on
-some targets that save registers into the caller's frame, such as SPARC
-and rs6000, and so such targets need to define this macro.
-
-You only need to define this macro if the default is incorrect, and you
-want to support call frame debugging information like that provided by
-DWARF 2.
-@end defmac
-
-@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl})
-If defined, a C expression whose value is an integer giving the offset
-in bytes from the frame pointer to the canonical frame address (cfa).
-The final value should coincide with that calculated by
-@code{INCOMING_FRAME_SP_OFFSET}.
-
-Normally the CFA is calculated as an offset from the argument pointer,
-via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
-variable due to the ABI, this may not be possible. If this macro is
-defined, it implies that the virtual register instantiation should be
-based on the frame pointer instead of the argument pointer. Only one
-of @code{FRAME_POINTER_CFA_OFFSET} and @code{ARG_POINTER_CFA_OFFSET}
-should be defined.
-@end defmac
-
-@defmac CFA_FRAME_BASE_OFFSET (@var{fundecl})
-If defined, a C expression whose value is an integer giving the offset
-in bytes from the canonical frame address (cfa) to the frame base used
-in DWARF 2 debug information. The default is zero. A different value
-may reduce the size of debug information on some ports.
-@end defmac
-
-@node Exception Handling
-@subsection Exception Handling Support
-@cindex exception handling
-
-@defmac EH_RETURN_DATA_REGNO (@var{N})
-A C expression whose value is the @var{N}th register number used for
-data by exception handlers, or @code{INVALID_REGNUM} if fewer than
-@var{N} registers are usable.
-
-The exception handling library routines communicate with the exception
-handlers via a set of agreed upon registers. Ideally these registers
-should be call-clobbered; it is possible to use call-saved registers,
-but may negatively impact code size. The target must support at least
-2 data registers, but should define 4 if there are enough free registers.
-
-You must define this macro if you want to support call frame exception
-handling like that provided by DWARF 2.
-@end defmac
-
-@defmac EH_RETURN_STACKADJ_RTX
-A C expression whose value is RTL representing a location in which
-to store a stack adjustment to be applied before function return.
-This is used to unwind the stack to an exception handler's call frame.
-It will be assigned zero on code paths that return normally.
-
-Typically this is a call-clobbered hard register that is otherwise
-untouched by the epilogue, but could also be a stack slot.
-
-Do not define this macro if the stack pointer is saved and restored
-by the regular prolog and epilog code in the call frame itself; in
-this case, the exception handling library routines will update the
-stack location to be restored in place. Otherwise, you must define
-this macro if you want to support call frame exception handling like
-that provided by DWARF 2.
-@end defmac
-
-@defmac EH_RETURN_HANDLER_RTX
-A C expression whose value is RTL representing a location in which
-to store the address of an exception handler to which we should
-return. It will not be assigned on code paths that return normally.
-
-Typically this is the location in the call frame at which the normal
-return address is stored. For targets that return by popping an
-address off the stack, this might be a memory address just below
-the @emph{target} call frame rather than inside the current call
-frame. If defined, @code{EH_RETURN_STACKADJ_RTX} will have already
-been assigned, so it may be used to calculate the location of the
-target call frame.
-
-Some targets have more complex requirements than storing to an
-address calculable during initial code generation. In that case
-the @code{eh_return} instruction pattern should be used instead.
-
-If you want to support call frame exception handling, you must
-define either this macro or the @code{eh_return} instruction pattern.
-@end defmac
-
-@defmac RETURN_ADDR_OFFSET
-If defined, an integer-valued C expression for which rtl will be generated
-to add it to the exception handler address before it is searched in the
-exception handling tables, and to subtract it again from the address before
-using it to return to the exception handler.
-@end defmac
-
-@defmac ASM_PREFERRED_EH_DATA_FORMAT (@var{code}, @var{global})
-This macro chooses the encoding of pointers embedded in the exception
-handling sections. If at all possible, this should be defined such
-that the exception handling section will not require dynamic relocations,
-and so may be read-only.
-
-@var{code} is 0 for data, 1 for code labels, 2 for function pointers.
-@var{global} is true if the symbol may be affected by dynamic relocations.
-The macro should return a combination of the @code{DW_EH_PE_*} defines
-as found in @file{dwarf2.h}.
-
-If this macro is not defined, pointers will not be encoded but
-represented directly.
-@end defmac
-
-@defmac ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
-This macro allows the target to emit whatever special magic is required
-to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}.
-Generic code takes care of pc-relative and indirect encodings; this must
-be defined if the target uses text-relative or data-relative encodings.
-
-This is a C statement that branches to @var{done} if the format was
-handled. @var{encoding} is the format chosen, @var{size} is the number
-of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF}
-to be emitted.
-@end defmac
-
-@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs})
-This macro allows the target to add CPU and operating system specific
-code to the call-frame unwinder for use when there is no unwind data
-available. The most common reason to implement this macro is to unwind
-through signal frames.
-
-This macro is called from @code{uw_frame_state_for} in
-@file{unwind-dw2.c}, @file{unwind-dw2-xtensa.c} and
-@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
-@var{fs} is an @code{_Unwind_FrameState}. Examine @code{context->ra}
-for the address of the code being executed and @code{context->cfa} for
-the stack pointer value. If the frame can be decoded, the register
-save addresses should be updated in @var{fs} and the macro should
-evaluate to @code{_URC_NO_REASON}. If the frame cannot be decoded,
-the macro should evaluate to @code{_URC_END_OF_STACK}.
-
-For proper signal handling in Java this macro is accompanied by
-@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers.
-@end defmac
-
-@defmac MD_HANDLE_UNWABI (@var{context}, @var{fs})
-This macro allows the target to add operating system specific code to the
-call-frame unwinder to handle the IA-64 @code{.unwabi} unwinding directive,
-usually used for signal or interrupt frames.
-
-This macro is called from @code{uw_update_context} in libgcc's
-@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
-@var{fs} is an @code{_Unwind_FrameState}. Examine @code{fs->unwabi}
-for the abi and context in the @code{.unwabi} directive. If the
-@code{.unwabi} directive can be handled, the register save addresses should
-be updated in @var{fs}.
-@end defmac
-
-@defmac TARGET_USES_WEAK_UNWIND_INFO
-A C expression that evaluates to true if the target requires unwind
-info to be given comdat linkage. Define it to be @code{1} if comdat
-linkage is necessary. The default is @code{0}.
-@end defmac
-
-@node Stack Checking
-@subsection Specifying How Stack Checking is Done
-
-GCC will check that stack references are within the boundaries of the
-stack, if the option @option{-fstack-check} is specified, in one of
-three ways:
-
-@enumerate
-@item
-If the value of the @code{STACK_CHECK_BUILTIN} macro is nonzero, GCC
-will assume that you have arranged for full stack checking to be done
-at appropriate places in the configuration files. GCC will not do
-other special processing.
-
-@item
-If @code{STACK_CHECK_BUILTIN} is zero and the value of the
-@code{STACK_CHECK_STATIC_BUILTIN} macro is nonzero, GCC will assume
-that you have arranged for static stack checking (checking of the
-static stack frame of functions) to be done at appropriate places
-in the configuration files. GCC will only emit code to do dynamic
-stack checking (checking on dynamic stack allocations) using the third
-approach below.
-
-@item
-If neither of the above are true, GCC will generate code to periodically
-``probe'' the stack pointer using the values of the macros defined below.
-@end enumerate
-
-If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is defined,
-GCC will change its allocation strategy for large objects if the option
-@option{-fstack-check} is specified: they will always be allocated
-dynamically if their size exceeds @code{STACK_CHECK_MAX_VAR_SIZE} bytes.
-
-@defmac STACK_CHECK_BUILTIN
-A nonzero value if stack checking is done by the configuration files in a
-machine-dependent manner. You should define this macro if stack checking
-is required by the ABI of your machine or if you would like to do stack
-checking in some more efficient way than the generic approach. The default
-value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_STATIC_BUILTIN
-A nonzero value if static stack checking is done by the configuration files
-in a machine-dependent manner. You should define this macro if you would
-like to do static stack checking in some more efficient way than the generic
-approach. The default value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_PROBE_INTERVAL_EXP
-An integer specifying the interval at which GCC must generate stack probe
-instructions, defined as 2 raised to this integer. You will normally
-define this macro so that the interval be no larger than the size of
-the ``guard pages'' at the end of a stack area. The default value
-of 12 (4096-byte interval) is suitable for most systems.
-@end defmac
-
-@defmac STACK_CHECK_MOVING_SP
-An integer which is nonzero if GCC should move the stack pointer page by page
-when doing probes. This can be necessary on systems where the stack pointer
-contains the bottom address of the memory area accessible to the executing
-thread at any point in time. In this situation an alternate signal stack
-is required in order to be able to recover from a stack overflow. The
-default value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_PROTECT
-The number of bytes of stack needed to recover from a stack overflow, for
-languages where such a recovery is supported. The default value of 4KB/8KB
-with the @code{setjmp}/@code{longjmp}-based exception handling mechanism and
-8KB/12KB with other exception handling mechanisms should be adequate for most
-architectures and operating systems.
-@end defmac
-
-The following macros are relevant only if neither STACK_CHECK_BUILTIN
-nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether
-in the opposite case.
-
-@defmac STACK_CHECK_MAX_FRAME_SIZE
-The maximum size of a stack frame, in bytes. GCC will generate probe
-instructions in non-leaf functions to ensure at least this many bytes of
-stack are available. If a stack frame is larger than this size, stack
-checking will not be reliable and GCC will issue a warning. The
-default is chosen so that GCC only generates one instruction on most
-systems. You should normally not change the default value of this macro.
-@end defmac
-
-@defmac STACK_CHECK_FIXED_FRAME_SIZE
-GCC uses this value to generate the above warning message. It
-represents the amount of fixed frame used by a function, not including
-space for any callee-saved registers, temporaries and user variables.
-You need only specify an upper bound for this amount and will normally
-use the default of four words.
-@end defmac
-
-@defmac STACK_CHECK_MAX_VAR_SIZE
-The maximum size, in bytes, of an object that GCC will place in the
-fixed area of the stack frame when the user specifies
-@option{-fstack-check}.
-GCC computed the default from the values of the above macros and you will
-normally not need to override that default.
-@end defmac
-
-@hook TARGET_STACK_CLASH_PROTECTION_ALLOCA_PROBE_RANGE
-
-@need 2000
-@node Frame Registers
-@subsection Registers That Address the Stack Frame
-
-@c prevent bad page break with this line
-This discusses registers that address the stack frame.
-
-@defmac STACK_POINTER_REGNUM
-The register number of the stack pointer register, which must also be a
-fixed register according to @code{FIXED_REGISTERS}. On most machines,
-the hardware determines which register this is.
-@end defmac
-
-@defmac FRAME_POINTER_REGNUM
-The register number of the frame pointer register, which is used to
-access automatic variables in the stack frame. On some machines, the
-hardware determines which register this is. On other machines, you can
-choose any register you wish for this purpose.
-@end defmac
-
-@defmac HARD_FRAME_POINTER_REGNUM
-On some machines the offset between the frame pointer and starting
-offset of the automatic variables is not known until after register
-allocation has been done (for example, because the saved registers are
-between these two locations). On those machines, define
-@code{FRAME_POINTER_REGNUM} the number of a special, fixed register to
-be used internally until the offset is known, and define
-@code{HARD_FRAME_POINTER_REGNUM} to be the actual hard register number
-used for the frame pointer.
-
-You should define this macro only in the very rare circumstances when it
-is not possible to calculate the offset between the frame pointer and
-the automatic variables until after register allocation has been
-completed. When this macro is defined, you must also indicate in your
-definition of @code{ELIMINABLE_REGS} how to eliminate
-@code{FRAME_POINTER_REGNUM} into either @code{HARD_FRAME_POINTER_REGNUM}
-or @code{STACK_POINTER_REGNUM}.
-
-Do not define this macro if it would be the same as
-@code{FRAME_POINTER_REGNUM}.
-@end defmac
-
-@defmac ARG_POINTER_REGNUM
-The register number of the arg pointer register, which is used to access
-the function's argument list. On some machines, this is the same as the
-frame pointer register. On some machines, the hardware determines which
-register this is. On other machines, you can choose any register you
-wish for this purpose. If this is not the same register as the frame
-pointer register, then you must mark it as a fixed register according to
-@code{FIXED_REGISTERS}, or arrange to be able to eliminate it
-(@pxref{Elimination}).
-@end defmac
-
-@defmac HARD_FRAME_POINTER_IS_FRAME_POINTER
-Define this to a preprocessor constant that is nonzero if
-@code{hard_frame_pointer_rtx} and @code{frame_pointer_rtx} should be
-the same. The default definition is @samp{(HARD_FRAME_POINTER_REGNUM
-== FRAME_POINTER_REGNUM)}; you only need to define this macro if that
-definition is not suitable for use in preprocessor conditionals.
-@end defmac
-
-@defmac HARD_FRAME_POINTER_IS_ARG_POINTER
-Define this to a preprocessor constant that is nonzero if
-@code{hard_frame_pointer_rtx} and @code{arg_pointer_rtx} should be the
-same. The default definition is @samp{(HARD_FRAME_POINTER_REGNUM ==
-ARG_POINTER_REGNUM)}; you only need to define this macro if that
-definition is not suitable for use in preprocessor conditionals.
-@end defmac
-
-@defmac RETURN_ADDRESS_POINTER_REGNUM
-The register number of the return address pointer register, which is used to
-access the current function's return address from the stack. On some
-machines, the return address is not at a fixed offset from the frame
-pointer or stack pointer or argument pointer. This register can be defined
-to point to the return address on the stack, and then be converted by
-@code{ELIMINABLE_REGS} into either the frame pointer or stack pointer.
-
-Do not define this macro unless there is no other way to get the return
-address from the stack.
-@end defmac
-
-@defmac STATIC_CHAIN_REGNUM
-@defmacx STATIC_CHAIN_INCOMING_REGNUM
-Register numbers used for passing a function's static chain pointer. If
-register windows are used, the register number as seen by the called
-function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register
-number as seen by the calling function is @code{STATIC_CHAIN_REGNUM}. If
-these registers are the same, @code{STATIC_CHAIN_INCOMING_REGNUM} need
-not be defined.
-
-The static chain register need not be a fixed register.
-
-If the static chain is passed in memory, these macros should not be
-defined; instead, the @code{TARGET_STATIC_CHAIN} hook should be used.
-@end defmac
-
-@hook TARGET_STATIC_CHAIN
-
-@defmac DWARF_FRAME_REGISTERS
-This macro specifies the maximum number of hard registers that can be
-saved in a call frame. This is used to size data structures used in
-DWARF2 exception handling.
-
-Prior to GCC 3.0, this macro was needed in order to establish a stable
-exception handling ABI in the face of adding new hard registers for ISA
-extensions. In GCC 3.0 and later, the EH ABI is insulated from changes
-in the number of hard registers. Nevertheless, this macro can still be
-used to reduce the runtime memory requirements of the exception handling
-routines, which can be substantial if the ISA contains a lot of
-registers that are not call-saved.
-
-If this macro is not defined, it defaults to
-@code{FIRST_PSEUDO_REGISTER}.
-@end defmac
-
-@defmac PRE_GCC3_DWARF_FRAME_REGISTERS
-
-This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided
-for backward compatibility in pre GCC 3.0 compiled code.
-
-If this macro is not defined, it defaults to
-@code{DWARF_FRAME_REGISTERS}.
-@end defmac
-
-@defmac DWARF_REG_TO_UNWIND_COLUMN (@var{regno})
-
-Define this macro if the target's representation for dwarf registers
-is different than the internal representation for unwind column.
-Given a dwarf register, this macro should return the internal unwind
-column number to use instead.
-@end defmac
-
-@defmac DWARF_FRAME_REGNUM (@var{regno})
-
-Define this macro if the target's representation for dwarf registers
-used in .eh_frame or .debug_frame is different from that used in other
-debug info sections. Given a GCC hard register number, this macro
-should return the .eh_frame register number. The default is
-@code{DBX_REGISTER_NUMBER (@var{regno})}.
-
-@end defmac
-
-@defmac DWARF2_FRAME_REG_OUT (@var{regno}, @var{for_eh})
-
-Define this macro to map register numbers held in the call frame info
-that GCC has collected using @code{DWARF_FRAME_REGNUM} to those that
-should be output in .debug_frame (@code{@var{for_eh}} is zero) and
-.eh_frame (@code{@var{for_eh}} is nonzero). The default is to
-return @code{@var{regno}}.
-
-@end defmac
-
-@defmac REG_VALUE_IN_UNWIND_CONTEXT
-
-Define this macro if the target stores register values as
-@code{_Unwind_Word} type in unwind context. It should be defined if
-target register size is larger than the size of @code{void *}. The
-default is to store register values as @code{void *} type.
-
-@end defmac
-
-@defmac ASSUME_EXTENDED_UNWIND_CONTEXT
-
-Define this macro to be 1 if the target always uses extended unwind
-context with version, args_size and by_value fields. If it is undefined,
-it will be defined to 1 when @code{REG_VALUE_IN_UNWIND_CONTEXT} is
-defined and 0 otherwise.
-
-@end defmac
-
-@defmac DWARF_LAZY_REGISTER_VALUE (@var{regno}, @var{value})
-Define this macro if the target has pseudo DWARF registers whose
-values need to be computed lazily on demand by the unwinder (such as when
-referenced in a CFA expression). The macro returns true if @var{regno}
-is such a register and stores its value in @samp{*@var{value}} if so.
-@end defmac
-
-@node Elimination
-@subsection Eliminating Frame Pointer and Arg Pointer
-
-@c prevent bad page break with this line
-This is about eliminating the frame pointer and arg pointer.
-
-@hook TARGET_FRAME_POINTER_REQUIRED
-
-@defmac ELIMINABLE_REGS
-This macro specifies a table of register pairs used to eliminate
-unneeded registers that point into the stack frame.
-
-The definition of this macro is a list of structure initializations, each
-of which specifies an original and replacement register.
-
-On some machines, the position of the argument pointer is not known until
-the compilation is completed. In such a case, a separate hard register
-must be used for the argument pointer. This register can be eliminated by
-replacing it with either the frame pointer or the argument pointer,
-depending on whether or not the frame pointer has been eliminated.
-
-In this case, you might specify:
-@smallexample
-#define ELIMINABLE_REGS \
-@{@{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM@}, \
- @{ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM@}, \
- @{FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM@}@}
-@end smallexample
-
-Note that the elimination of the argument pointer with the stack pointer is
-specified first since that is the preferred elimination.
-@end defmac
-
-@hook TARGET_CAN_ELIMINATE
-
-@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
-This macro returns the initial difference between the specified pair
-of registers. The value would be computed from information
-such as the result of @code{get_frame_size ()} and the tables of
-registers @code{df_regs_ever_live_p} and @code{call_used_regs}.
-@end defmac
-
-@hook TARGET_COMPUTE_FRAME_LAYOUT
-
-@node Stack Arguments
-@subsection Passing Function Arguments on the Stack
-@cindex arguments on stack
-@cindex stack arguments
-
-The macros in this section control how arguments are passed
-on the stack. See the following section for other macros that
-control passing certain arguments in registers.
-
-@hook TARGET_PROMOTE_PROTOTYPES
-
-@hook TARGET_PUSH_ARGUMENT
-
-@defmac PUSH_ARGS_REVERSED
-A C expression. If nonzero, function arguments will be evaluated from
-last to first, rather than from first to last. If this macro is not
-defined, it defaults to @code{PUSH_ARGS} on targets where the stack
-and args grow in opposite directions, and 0 otherwise.
-@end defmac
-
-@defmac PUSH_ROUNDING (@var{npushed})
-A C expression that is the number of bytes actually pushed onto the
-stack when an instruction attempts to push @var{npushed} bytes.
-
-On some machines, the definition
-
-@smallexample
-#define PUSH_ROUNDING(BYTES) (BYTES)
-@end smallexample
-
-@noindent
-will suffice. But on other machines, instructions that appear
-to push one byte actually push two bytes in an attempt to maintain
-alignment. Then the definition should be
-
-@smallexample
-#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1)
-@end smallexample
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@findex outgoing_args_size
-@findex crtl->outgoing_args_size
-@defmac ACCUMULATE_OUTGOING_ARGS
-A C expression. If nonzero, the maximum amount of space required for outgoing arguments
-will be computed and placed into
-@code{crtl->outgoing_args_size}. No space will be pushed
-onto the stack for each call; instead, the function prologue should
-increase the stack frame size by this amount.
-
-Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS}
-is not proper.
-@end defmac
-
-@defmac REG_PARM_STACK_SPACE (@var{fndecl})
-Define this macro if functions should assume that stack space has been
-allocated for arguments even when their values are passed in
-registers.
-
-The value of this macro is the size, in bytes, of the area reserved for
-arguments passed in registers for the function represented by @var{fndecl},
-which can be zero if GCC is calling a library function.
-The argument @var{fndecl} can be the FUNCTION_DECL, or the type itself
-of the function.
-
-This space can be allocated by the caller, or be a part of the
-machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says
-which.
-@end defmac
-@c above is overfull. not sure what to do. --mew 5feb93 did
-@c something, not sure if it looks good. --mew 10feb93
-
-@defmac INCOMING_REG_PARM_STACK_SPACE (@var{fndecl})
-Like @code{REG_PARM_STACK_SPACE}, but for incoming register arguments.
-Define this macro if space guaranteed when compiling a function body
-is different to space required when making a call, a situation that
-can arise with K&R style function definitions.
-@end defmac
-
-@defmac OUTGOING_REG_PARM_STACK_SPACE (@var{fntype})
-Define this to a nonzero value if it is the responsibility of the
-caller to allocate the area reserved for arguments passed in registers
-when calling a function of @var{fntype}. @var{fntype} may be NULL
-if the function called is a library function.
-
-If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
-whether the space for these arguments counts in the value of
-@code{crtl->outgoing_args_size}.
-@end defmac
-
-@defmac STACK_PARMS_IN_REG_PARM_AREA
-Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the
-stack parameters don't skip the area specified by it.
-@c i changed this, makes more sens and it should have taken care of the
-@c overfull.. not as specific, tho. --mew 5feb93
-
-Normally, when a parameter is not passed in registers, it is placed on the
-stack beyond the @code{REG_PARM_STACK_SPACE} area. Defining this macro
-suppresses this behavior and causes the parameter to be passed on the
-stack in its natural location.
-@end defmac
-
-@hook TARGET_RETURN_POPS_ARGS
-
-@defmac CALL_POPS_ARGS (@var{cum})
-A C expression that should indicate the number of bytes a call sequence
-pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS}
-when compiling a function call.
-
-@var{cum} is the variable in which all arguments to the called function
-have been accumulated.
-
-On certain architectures, such as the SH5, a call trampoline is used
-that pops certain registers off the stack, depending on the arguments
-that have been passed to the function. Since this is a property of the
-call site, not of the called function, @code{RETURN_POPS_ARGS} is not
-appropriate.
-@end defmac
-
-@node Register Arguments
-@subsection Passing Arguments in Registers
-@cindex arguments in registers
-@cindex registers arguments
-
-This section describes the macros which let you control how various
-types of arguments are passed in registers or how they are arranged in
-the stack.
-
-@hook TARGET_FUNCTION_ARG
-
-@hook TARGET_MUST_PASS_IN_STACK
-
-@hook TARGET_FUNCTION_INCOMING_ARG
-
-@hook TARGET_USE_PSEUDO_PIC_REG
-
-@hook TARGET_INIT_PIC_REG
-
-@hook TARGET_ARG_PARTIAL_BYTES
-
-@hook TARGET_PASS_BY_REFERENCE
-
-@hook TARGET_CALLEE_COPIES
-
-@defmac CUMULATIVE_ARGS
-A C type for declaring a variable that is used as the first argument
-of @code{TARGET_FUNCTION_ARG} and other related values. For some
-target machines, the type @code{int} suffices and can hold the number
-of bytes of argument so far.
-
-There is no need to record in @code{CUMULATIVE_ARGS} anything about the
-arguments that have been passed on the stack. The compiler has other
-variables to keep track of that. For target machines on which all
-arguments are passed on the stack, there is no need to store anything in
-@code{CUMULATIVE_ARGS}; however, the data structure must exist and
-should not be empty, so use @code{int}.
-@end defmac
-
-@defmac OVERRIDE_ABI_FORMAT (@var{fndecl})
-If defined, this macro is called before generating any code for a
-function, but after the @var{cfun} descriptor for the function has been
-created. The back end may use this macro to update @var{cfun} to
-reflect an ABI other than that which would normally be used by default.
-If the compiler is generating code for a compiler-generated function,
-@var{fndecl} may be @code{NULL}.
-@end defmac
-
-@defmac INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{fndecl}, @var{n_named_args})
-A C statement (sans semicolon) for initializing the variable
-@var{cum} for the state at the beginning of the argument list. The
-variable has type @code{CUMULATIVE_ARGS}. The value of @var{fntype}
-is the tree node for the data type of the function which will receive
-the args, or 0 if the args are to a compiler support library function.
-For direct calls that are not libcalls, @var{fndecl} contain the
-declaration node of the function. @var{fndecl} is also set when
-@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function
-being compiled. @var{n_named_args} is set to the number of named
-arguments, including a structure return address if it is passed as a
-parameter, when making a call. When processing incoming arguments,
-@var{n_named_args} is set to @minus{}1.
-
-When processing a call to a compiler support library function,
-@var{libname} identifies which one. It is a @code{symbol_ref} rtx which
-contains the name of the function, as a string. @var{libname} is 0 when
-an ordinary C function call is being processed. Thus, each time this
-macro is called, either @var{libname} or @var{fntype} is nonzero, but
-never both of them at once.
-@end defmac
-
-@defmac INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
-Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls,
-it gets a @code{MODE} argument instead of @var{fntype}, that would be
-@code{NULL}. @var{indirect} would always be zero, too. If this macro
-is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname,
-0)} is used instead.
-@end defmac
-
-@defmac INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
-Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of
-finding the arguments for the function being compiled. If this macro is
-undefined, @code{INIT_CUMULATIVE_ARGS} is used instead.
-
-The value passed for @var{libname} is always 0, since library routines
-with special calling conventions are never compiled with GCC@. The
-argument @var{libname} exists for symmetry with
-@code{INIT_CUMULATIVE_ARGS}.
-@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe.
-@c --mew 5feb93 i switched the order of the sentences. --mew 10feb93
-@end defmac
-
-@hook TARGET_FUNCTION_ARG_ADVANCE
-
-@hook TARGET_FUNCTION_ARG_OFFSET
-
-@hook TARGET_FUNCTION_ARG_PADDING
-
-@defmac PAD_VARARGS_DOWN
-If defined, a C expression which determines whether the default
-implementation of va_arg will attempt to pad down before reading the
-next argument, if that argument is smaller than its aligned space as
-controlled by @code{PARM_BOUNDARY}. If this macro is not defined, all such
-arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
-@end defmac
-
-@defmac BLOCK_REG_PADDING (@var{mode}, @var{type}, @var{first})
-Specify padding for the last element of a block move between registers and
-memory. @var{first} is nonzero if this is the only element. Defining this
-macro allows better control of register function parameters on big-endian
-machines, without using @code{PARALLEL} rtl. In particular,
-@code{MUST_PASS_IN_STACK} need not test padding and mode of types in
-registers, as there is no longer a "wrong" part of a register; For example,
-a three byte aggregate may be passed in the high part of a register if so
-required.
-@end defmac
-
-@hook TARGET_FUNCTION_ARG_BOUNDARY
-
-@hook TARGET_FUNCTION_ARG_ROUND_BOUNDARY
-
-@defmac FUNCTION_ARG_REGNO_P (@var{regno})
-A C expression that is nonzero if @var{regno} is the number of a hard
-register in which function arguments are sometimes passed. This does
-@emph{not} include implicit arguments such as the static chain and
-the structure-value address. On many machines, no registers can be
-used for this purpose since all function arguments are pushed on the
-stack.
-@end defmac
-
-@hook TARGET_SPLIT_COMPLEX_ARG
-
-@hook TARGET_BUILD_BUILTIN_VA_LIST
-
-@hook TARGET_ENUM_VA_LIST_P
-
-@hook TARGET_FN_ABI_VA_LIST
-
-@hook TARGET_CANONICAL_VA_LIST_TYPE
-
-@hook TARGET_GIMPLIFY_VA_ARG_EXPR
-
-@hook TARGET_VALID_POINTER_MODE
-
-@hook TARGET_REF_MAY_ALIAS_ERRNO
-
-@hook TARGET_TRANSLATE_MODE_ATTRIBUTE
-
-@hook TARGET_SCALAR_MODE_SUPPORTED_P
-
-@hook TARGET_VECTOR_MODE_SUPPORTED_P
-
-@hook TARGET_COMPATIBLE_VECTOR_TYPES_P
-
-@hook TARGET_ARRAY_MODE
-
-@hook TARGET_ARRAY_MODE_SUPPORTED_P
-
-@hook TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P
-
-@hook TARGET_FLOATN_MODE
-
-@hook TARGET_FLOATN_BUILTIN_P
-
-@hook TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
-
-@node Scalar Return
-@subsection How Scalar Function Values Are Returned
-@cindex return values in registers
-@cindex values, returned by functions
-@cindex scalars, returned as values
-
-This section discusses the macros that control returning scalars as
-values---values that can fit in registers.
-
-@hook TARGET_FUNCTION_VALUE
-
-@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
-This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
-a new target instead.
-@end defmac
-
-@defmac LIBCALL_VALUE (@var{mode})
-A C expression to create an RTX representing the place where a library
-function returns a value of mode @var{mode}.
-
-Note that ``library function'' in this context means a compiler
-support routine, used to perform arithmetic, whose name is known
-specially by the compiler and was not mentioned in the C code being
-compiled.
-@end defmac
-
-@hook TARGET_LIBCALL_VALUE
-
-@defmac FUNCTION_VALUE_REGNO_P (@var{regno})
-A C expression that is nonzero if @var{regno} is the number of a hard
-register in which the values of called function may come back.
-
-A register whose use for returning values is limited to serving as the
-second of a pair (for a value of type @code{double}, say) need not be
-recognized by this macro. So for most machines, this definition
-suffices:
-
-@smallexample
-#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0)
-@end smallexample
-
-If the machine has register windows, so that the caller and the called
-function use different registers for the return value, this macro
-should recognize only the caller's register numbers.
-
-This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE_REGNO_P}
-for a new target instead.
-@end defmac
-
-@hook TARGET_FUNCTION_VALUE_REGNO_P
-
-@defmac APPLY_RESULT_SIZE
-Define this macro if @samp{untyped_call} and @samp{untyped_return}
-need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for
-saving and restoring an arbitrary return value.
-@end defmac
-
-@hook TARGET_OMIT_STRUCT_RETURN_REG
-
-@hook TARGET_RETURN_IN_MSB
-
-@node Aggregate Return
-@subsection How Large Values Are Returned
-@cindex aggregates as return values
-@cindex large return values
-@cindex returning aggregate values
-@cindex structure value address
-
-When a function value's mode is @code{BLKmode} (and in some other
-cases), the value is not returned according to
-@code{TARGET_FUNCTION_VALUE} (@pxref{Scalar Return}). Instead, the
-caller passes the address of a block of memory in which the value
-should be stored. This address is called the @dfn{structure value
-address}.
-
-This section describes how to control returning structure values in
-memory.
-
-@hook TARGET_RETURN_IN_MEMORY
-
-@defmac DEFAULT_PCC_STRUCT_RETURN
-Define this macro to be 1 if all structure and union return values must be
-in memory. Since this results in slower code, this should be defined
-only if needed for compatibility with other compilers or with an ABI@.
-If you define this macro to be 0, then the conventions used for structure
-and union return values are decided by the @code{TARGET_RETURN_IN_MEMORY}
-target hook.
-
-If not defined, this defaults to the value 1.
-@end defmac
-
-@hook TARGET_STRUCT_VALUE_RTX
-
-@defmac PCC_STATIC_STRUCT_RETURN
-Define this macro if the usual system convention on the target machine
-for returning structures and unions is for the called function to return
-the address of a static variable containing the value.
-
-Do not define this if the usual system convention is for the caller to
-pass an address to the subroutine.
-
-This macro has effect in @option{-fpcc-struct-return} mode, but it does
-nothing when you use @option{-freg-struct-return} mode.
-@end defmac
-
-@hook TARGET_GET_RAW_RESULT_MODE
-
-@hook TARGET_GET_RAW_ARG_MODE
-
-@hook TARGET_EMPTY_RECORD_P
-
-@hook TARGET_WARN_PARAMETER_PASSING_ABI
-
-@node Caller Saves
-@subsection Caller-Saves Register Allocation
-
-If you enable it, GCC can save registers around function calls. This
-makes it possible to use call-clobbered registers to hold variables that
-must live across calls.
-
-@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
-A C expression specifying which mode is required for saving @var{nregs}
-of a pseudo-register in call-clobbered hard register @var{regno}. If
-@var{regno} is unsuitable for caller save, @code{VOIDmode} should be
-returned. For most machines this macro need not be defined since GCC
-will select the smallest suitable mode.
-@end defmac
-
-@node Function Entry
-@subsection Function Entry and Exit
-@cindex function entry and exit
-@cindex prologue
-@cindex epilogue
-
-This section describes the macros that output function entry
-(@dfn{prologue}) and exit (@dfn{epilogue}) code.
-
-@hook TARGET_ASM_PRINT_PATCHABLE_FUNCTION_ENTRY
-
-@hook TARGET_ASM_FUNCTION_PROLOGUE
-
-@hook TARGET_ASM_FUNCTION_END_PROLOGUE
-
-@hook TARGET_ASM_FUNCTION_BEGIN_EPILOGUE
-
-@hook TARGET_ASM_FUNCTION_EPILOGUE
-
-@itemize @bullet
-@item
-@findex pretend_args_size
-@findex crtl->args.pretend_args_size
-A region of @code{crtl->args.pretend_args_size} bytes of
-uninitialized space just underneath the first argument arriving on the
-stack. (This may not be at the very start of the allocated stack region
-if the calling sequence has pushed anything else since pushing the stack
-arguments. But usually, on such machines, nothing else has been pushed
-yet, because the function prologue itself does all the pushing.) This
-region is used on machines where an argument may be passed partly in
-registers and partly in memory, and, in some cases to support the
-features in @code{<stdarg.h>}.
-
-@item
-An area of memory used to save certain registers used by the function.
-The size of this area, which may also include space for such things as
-the return address and pointers to previous stack frames, is
-machine-specific and usually depends on which registers have been used
-in the function. Machines with register windows often do not require
-a save area.
-
-@item
-A region of at least @var{size} bytes, possibly rounded up to an allocation
-boundary, to contain the local variables of the function. On some machines,
-this region and the save area may occur in the opposite order, with the
-save area closer to the top of the stack.
-
-@item
-@cindex @code{ACCUMULATE_OUTGOING_ARGS} and stack frames
-Optionally, when @code{ACCUMULATE_OUTGOING_ARGS} is defined, a region of
-@code{crtl->outgoing_args_size} bytes to be used for outgoing
-argument lists of the function. @xref{Stack Arguments}.
-@end itemize
-
-@defmac EXIT_IGNORE_STACK
-Define this macro as a C expression that is nonzero if the return
-instruction or the function epilogue ignores the value of the stack
-pointer; in other words, if it is safe to delete an instruction to
-adjust the stack pointer before a return from the function. The
-default is 0.
-
-Note that this macro's value is relevant only for functions for which
-frame pointers are maintained. It is never safe to delete a final
-stack adjustment in a function that has no frame pointer, and the
-compiler knows this regardless of @code{EXIT_IGNORE_STACK}.
-@end defmac
-
-@defmac EPILOGUE_USES (@var{regno})
-Define this macro as a C expression that is nonzero for registers that are
-used by the epilogue or the @samp{return} pattern. The stack and frame
-pointer registers are already assumed to be used as needed.
-@end defmac
-
-@defmac EH_USES (@var{regno})
-Define this macro as a C expression that is nonzero for registers that are
-used by the exception handling mechanism, and so should be considered live
-on entry to an exception edge.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_MI_THUNK
-
-@hook TARGET_ASM_CAN_OUTPUT_MI_THUNK
-
-@node Profiling
-@subsection Generating Code for Profiling
-@cindex profiling, code generation
-
-These macros will help you generate code for profiling.
-
-@defmac FUNCTION_PROFILER (@var{file}, @var{labelno})
-A C statement or compound statement to output to @var{file} some
-assembler code to call the profiling subroutine @code{mcount}.
-
-@findex mcount
-The details of how @code{mcount} expects to be called are determined by
-your operating system environment, not by GCC@. To figure them out,
-compile a small program for profiling using the system's installed C
-compiler and look at the assembler code that results.
-
-Older implementations of @code{mcount} expect the address of a counter
-variable to be loaded into some register. The name of this variable is
-@samp{LP} followed by the number @var{labelno}, so you would generate
-the name using @samp{LP%d} in a @code{fprintf}.
-@end defmac
-
-@defmac PROFILE_HOOK
-A C statement or compound statement to output to @var{file} some assembly
-code to call the profiling subroutine @code{mcount} even the target does
-not support profiling.
-@end defmac
-
-@defmac NO_PROFILE_COUNTERS
-Define this macro to be an expression with a nonzero value if the
-@code{mcount} subroutine on your system does not need a counter variable
-allocated for each function. This is true for almost all modern
-implementations. If you define this macro, you must not use the
-@var{labelno} argument to @code{FUNCTION_PROFILER}.
-@end defmac
-
-@defmac PROFILE_BEFORE_PROLOGUE
-Define this macro if the code for function profiling should come before
-the function prologue. Normally, the profiling code comes after.
-@end defmac
-
-@hook TARGET_KEEP_LEAF_WHEN_PROFILED
-
-@node Tail Calls
-@subsection Permitting tail calls
-@cindex tail calls
-
-@hook TARGET_FUNCTION_OK_FOR_SIBCALL
-
-@hook TARGET_EXTRA_LIVE_ON_ENTRY
-
-@hook TARGET_SET_UP_BY_PROLOGUE
-
-@hook TARGET_WARN_FUNC_RETURN
-
-@node Shrink-wrapping separate components
-@subsection Shrink-wrapping separate components
-@cindex shrink-wrapping separate components
-
-The prologue may perform a variety of target dependent tasks such as
-saving callee-saved registers, saving the return address, aligning the
-stack, creating a stack frame, initializing the PIC register, setting
-up the static chain, etc.
-
-On some targets some of these tasks may be independent of others and
-thus may be shrink-wrapped separately. These independent tasks are
-referred to as components and are handled generically by the target
-independent parts of GCC.
-
-Using the following hooks those prologue or epilogue components can be
-shrink-wrapped separately, so that the initialization (and possibly
-teardown) those components do is not done as frequently on execution
-paths where this would unnecessary.
-
-What exactly those components are is up to the target code; the generic
-code treats them abstractly, as a bit in an @code{sbitmap}. These
-@code{sbitmap}s are allocated by the @code{shrink_wrap.get_separate_components}
-and @code{shrink_wrap.components_for_bb} hooks, and deallocated by the
-generic code.
-
-@hook TARGET_SHRINK_WRAP_GET_SEPARATE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_COMPONENTS_FOR_BB
-
-@hook TARGET_SHRINK_WRAP_DISQUALIFY_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_EMIT_PROLOGUE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_EMIT_EPILOGUE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_SET_HANDLED_COMPONENTS
-
-@node Stack Smashing Protection
-@subsection Stack smashing protection
-@cindex stack smashing protection
-
-@hook TARGET_STACK_PROTECT_GUARD
-
-@hook TARGET_STACK_PROTECT_FAIL
-
-@hook TARGET_STACK_PROTECT_RUNTIME_ENABLED_P
-
-@hook TARGET_SUPPORTS_SPLIT_STACK
-
-@hook TARGET_GET_VALID_OPTION_VALUES
-
-@node Miscellaneous Register Hooks
-@subsection Miscellaneous register hooks
-@cindex miscellaneous register hooks
-
-@hook TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS
-
-@node Varargs
-@section Implementing the Varargs Macros
-@cindex varargs implementation
-
-GCC comes with an implementation of @code{<varargs.h>} and
-@code{<stdarg.h>} that work without change on machines that pass arguments
-on the stack. Other machines require their own implementations of
-varargs, and the two machine independent header files must have
-conditionals to include it.
-
-ISO @code{<stdarg.h>} differs from traditional @code{<varargs.h>} mainly in
-the calling convention for @code{va_start}. The traditional
-implementation takes just one argument, which is the variable in which
-to store the argument pointer. The ISO implementation of
-@code{va_start} takes an additional second argument. The user is
-supposed to write the last named argument of the function here.
-
-However, @code{va_start} should not use this argument. The way to find
-the end of the named arguments is with the built-in functions described
-below.
-
-@defmac __builtin_saveregs ()
-Use this built-in function to save the argument registers in memory so
-that the varargs mechanism can access them. Both ISO and traditional
-versions of @code{va_start} must use @code{__builtin_saveregs}, unless
-you use @code{TARGET_SETUP_INCOMING_VARARGS} (see below) instead.
-
-On some machines, @code{__builtin_saveregs} is open-coded under the
-control of the target hook @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. On
-other machines, it calls a routine written in assembler language,
-found in @file{libgcc2.c}.
-
-Code generated for the call to @code{__builtin_saveregs} appears at the
-beginning of the function, as opposed to where the call to
-@code{__builtin_saveregs} is written, regardless of what the code is.
-This is because the registers must be saved before the function starts
-to use them for its own purposes.
-@c i rewrote the first sentence above to fix an overfull hbox. --mew
-@c 10feb93
-@end defmac
-
-@defmac __builtin_next_arg (@var{lastarg})
-This builtin returns the address of the first anonymous stack
-argument, as type @code{void *}. If @code{ARGS_GROW_DOWNWARD}, it
-returns the address of the location above the first anonymous stack
-argument. Use it in @code{va_start} to initialize the pointer for
-fetching arguments from the stack. Also use it in @code{va_start} to
-verify that the second parameter @var{lastarg} is the last named argument
-of the current function.
-@end defmac
-
-@defmac __builtin_classify_type (@var{object})
-Since each machine has its own conventions for which data types are
-passed in which kind of register, your implementation of @code{va_arg}
-has to embody these conventions. The easiest way to categorize the
-specified data type is to use @code{__builtin_classify_type} together
-with @code{sizeof} and @code{__alignof__}.
-
-@code{__builtin_classify_type} ignores the value of @var{object},
-considering only its data type. It returns an integer describing what
-kind of type that is---integer, floating, pointer, structure, and so on.
-
-The file @file{typeclass.h} defines an enumeration that you can use to
-interpret the values of @code{__builtin_classify_type}.
-@end defmac
-
-These machine description macros help implement varargs:
-
-@hook TARGET_EXPAND_BUILTIN_SAVEREGS
-
-@hook TARGET_SETUP_INCOMING_VARARGS
-
-@hook TARGET_STRICT_ARGUMENT_NAMING
-
-@hook TARGET_CALL_ARGS
-
-@hook TARGET_END_CALL_ARGS
-
-@hook TARGET_PRETEND_OUTGOING_VARARGS_NAMED
-
-@node Trampolines
-@section Support for Nested Functions
-@cindex support for nested functions
-@cindex trampolines for nested functions
-@cindex descriptors for nested functions
-@cindex nested functions, support for
-
-Taking the address of a nested function requires special compiler
-handling to ensure that the static chain register is loaded when
-the function is invoked via an indirect call.
-
-GCC has traditionally supported nested functions by creating an
-executable @dfn{trampoline} at run time when the address of a nested
-function is taken. This is a small piece of code which normally
-resides on the stack, in the stack frame of the containing function.
-The trampoline loads the static chain register and then jumps to the
-real address of the nested function.
-
-The use of trampolines requires an executable stack, which is a
-security risk. To avoid this problem, GCC also supports another
-strategy: using descriptors for nested functions. Under this model,
-taking the address of a nested function results in a pointer to a
-non-executable function descriptor object. Initializing the static chain
-from the descriptor is handled at indirect call sites.
-
-On some targets, including HPPA and IA-64, function descriptors may be
-mandated by the ABI or be otherwise handled in a target-specific way
-by the back end in its code generation strategy for indirect calls.
-GCC also provides its own generic descriptor implementation to support the
-@option{-fno-trampolines} option. In this case runtime detection of
-function descriptors at indirect call sites relies on descriptor
-pointers being tagged with a bit that is never set in bare function
-addresses. Since GCC's generic function descriptors are
-not ABI-compliant, this option is typically used only on a
-per-language basis (notably by Ada) or when it can otherwise be
-applied to the whole program.
-
-For languages other than Ada, the @code{-ftrampolines} and
-@code{-fno-trampolines} options currently have no effect, and
-trampolines are always generated on platforms that need them
-for nested functions.
-
-Define the following hook if your backend either implements ABI-specified
-descriptor support, or can use GCC's generic descriptor implementation
-for nested functions.
-
-@hook TARGET_CUSTOM_FUNCTION_DESCRIPTORS
-
-The following macros tell GCC how to generate code to allocate and
-initialize an executable trampoline. You can also use this interface
-if your back end needs to create ABI-specified non-executable descriptors; in
-this case the "trampoline" created is the descriptor containing data only.
-
-The instructions in an executable trampoline must do two things: load
-a constant address into the static chain register, and jump to the real
-address of the nested function. On CISC machines such as the m68k,
-this requires two instructions, a move immediate and a jump. Then the
-two addresses exist in the trampoline as word-long immediate operands.
-On RISC machines, it is often necessary to load each address into a
-register in two parts. Then pieces of each address form separate
-immediate operands.
-
-The code generated to initialize the trampoline must store the variable
-parts---the static chain value and the function address---into the
-immediate operands of the instructions. On a CISC machine, this is
-simply a matter of copying each address to a memory reference at the
-proper offset from the start of the trampoline. On a RISC machine, it
-may be necessary to take out pieces of the address and store them
-separately.
-
-@hook TARGET_ASM_TRAMPOLINE_TEMPLATE
-
-@defmac TRAMPOLINE_SECTION
-Return the section into which the trampoline template is to be placed
-(@pxref{Sections}). The default value is @code{readonly_data_section}.
-@end defmac
-
-@defmac TRAMPOLINE_SIZE
-A C expression for the size in bytes of the trampoline, as an integer.
-@end defmac
-
-@defmac TRAMPOLINE_ALIGNMENT
-Alignment required for trampolines, in bits.
-
-If you don't define this macro, the value of @code{FUNCTION_ALIGNMENT}
-is used for aligning trampolines.
-@end defmac
-
-@hook TARGET_TRAMPOLINE_INIT
-
-@hook TARGET_EMIT_CALL_BUILTIN___CLEAR_CACHE
-
-@hook TARGET_TRAMPOLINE_ADJUST_ADDRESS
-
-Implementing trampolines is difficult on many machines because they have
-separate instruction and data caches. Writing into a stack location
-fails to clear the memory in the instruction cache, so when the program
-jumps to that location, it executes the old contents.
-
-Here are two possible solutions. One is to clear the relevant parts of
-the instruction cache whenever a trampoline is set up. The other is to
-make all trampolines identical, by having them jump to a standard
-subroutine. The former technique makes trampoline execution faster; the
-latter makes initialization faster.
-
-To clear the instruction cache when a trampoline is initialized, define
-the following macro.
-
-@defmac CLEAR_INSN_CACHE (@var{beg}, @var{end})
-If defined, expands to a C expression clearing the @emph{instruction
-cache} in the specified interval. The definition of this macro would
-typically be a series of @code{asm} statements. Both @var{beg} and
-@var{end} are pointer expressions.
-@end defmac
-
-To use a standard subroutine, define the following macro. In addition,
-you must make sure that the instructions in a trampoline fill an entire
-cache line with identical instructions, or else ensure that the
-beginning of the trampoline code is always aligned at the same point in
-its cache line. Look in @file{m68k.h} as a guide.
-
-@defmac TRANSFER_FROM_TRAMPOLINE
-Define this macro if trampolines need a special subroutine to do their
-work. The macro should expand to a series of @code{asm} statements
-which will be compiled with GCC@. They go in a library function named
-@code{__transfer_from_trampoline}.
-
-If you need to avoid executing the ordinary prologue code of a compiled
-C function when you jump to the subroutine, you can do so by placing a
-special label of your own in the assembler code. Use one @code{asm}
-statement to generate an assembler label, and another to make the label
-global. Then trampolines can use that label to jump directly to your
-special assembler code.
-@end defmac
-
-@node Library Calls
-@section Implicit Calls to Library Routines
-@cindex library subroutine names
-@cindex @file{libgcc.a}
-
-@c prevent bad page break with this line
-Here is an explanation of implicit calls to library routines.
-
-@defmac DECLARE_LIBRARY_RENAMES
-This macro, if defined, should expand to a piece of C code that will get
-expanded when compiling functions for libgcc.a. It can be used to
-provide alternate names for GCC's internal library functions if there
-are ABI-mandated names that the compiler should provide.
-@end defmac
-
-@findex set_optab_libfunc
-@findex init_one_libfunc
-@hook TARGET_INIT_LIBFUNCS
-
-@hook TARGET_LIBFUNC_GNU_PREFIX
-
-@defmac FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
-This macro should return @code{true} if the library routine that
-implements the floating point comparison operator @var{comparison} in
-mode @var{mode} will return a boolean, and @var{false} if it will
-return a tristate.
-
-GCC's own floating point libraries return tristates from the
-comparison operators, so the default returns false always. Most ports
-don't need to define this macro.
-@end defmac
-
-@defmac TARGET_LIB_INT_CMP_BIASED
-This macro should evaluate to @code{true} if the integer comparison
-functions (like @code{__cmpdi2}) return 0 to indicate that the first
-operand is smaller than the second, 1 to indicate that they are equal,
-and 2 to indicate that the first operand is greater than the second.
-If this macro evaluates to @code{false} the comparison functions return
-@minus{}1, 0, and 1 instead of 0, 1, and 2. If the target uses the routines
-in @file{libgcc.a}, you do not need to define this macro.
-@end defmac
-
-@defmac TARGET_HAS_NO_HW_DIVIDE
-This macro should be defined if the target has no hardware divide
-instructions. If this macro is defined, GCC will use an algorithm which
-make use of simple logical and arithmetic operations for 64-bit
-division. If the macro is not defined, GCC will use an algorithm which
-make use of a 64-bit by 32-bit divide primitive.
-@end defmac
-
-@cindex @code{EDOM}, implicit usage
-@findex matherr
-@defmac TARGET_EDOM
-The value of @code{EDOM} on the target machine, as a C integer constant
-expression. If you don't define this macro, GCC does not attempt to
-deposit the value of @code{EDOM} into @code{errno} directly. Look in
-@file{/usr/include/errno.h} to find the value of @code{EDOM} on your
-system.
-
-If you do not define @code{TARGET_EDOM}, then compiled code reports
-domain errors by calling the library function and letting it report the
-error. If mathematical functions on your system use @code{matherr} when
-there is an error, then you should leave @code{TARGET_EDOM} undefined so
-that @code{matherr} is used normally.
-@end defmac
-
-@cindex @code{errno}, implicit usage
-@defmac GEN_ERRNO_RTX
-Define this macro as a C expression to create an rtl expression that
-refers to the global ``variable'' @code{errno}. (On certain systems,
-@code{errno} may not actually be a variable.) If you don't define this
-macro, a reasonable default is used.
-@end defmac
-
-@hook TARGET_LIBC_HAS_FUNCTION
-
-@hook TARGET_LIBC_HAS_FAST_FUNCTION
-
-@defmac NEXT_OBJC_RUNTIME
-Set this macro to 1 to use the "NeXT" Objective-C message sending conventions
-by default. This calling convention involves passing the object, the selector
-and the method arguments all at once to the method-lookup library function.
-This is the usual setting when targeting Darwin/Mac OS X systems, which have
-the NeXT runtime installed.
-
-If the macro is set to 0, the "GNU" Objective-C message sending convention
-will be used by default. This convention passes just the object and the
-selector to the method-lookup function, which returns a pointer to the method.
-
-In either case, it remains possible to select code-generation for the alternate
-scheme, by means of compiler command line switches.
-@end defmac
-
-@node Addressing Modes
-@section Addressing Modes
-@cindex addressing modes
-
-@c prevent bad page break with this line
-This is about addressing modes.
-
-@defmac HAVE_PRE_INCREMENT
-@defmacx HAVE_PRE_DECREMENT
-@defmacx HAVE_POST_INCREMENT
-@defmacx HAVE_POST_DECREMENT
-A C expression that is nonzero if the machine supports pre-increment,
-pre-decrement, post-increment, or post-decrement addressing respectively.
-@end defmac
-
-@defmac HAVE_PRE_MODIFY_DISP
-@defmacx HAVE_POST_MODIFY_DISP
-A C expression that is nonzero if the machine supports pre- or
-post-address side-effect generation involving constants other than
-the size of the memory operand.
-@end defmac
-
-@defmac HAVE_PRE_MODIFY_REG
-@defmacx HAVE_POST_MODIFY_REG
-A C expression that is nonzero if the machine supports pre- or
-post-address side-effect generation involving a register displacement.
-@end defmac
-
-@defmac CONSTANT_ADDRESS_P (@var{x})
-A C expression that is 1 if the RTX @var{x} is a constant which
-is a valid address. On most machines the default definition of
-@code{(CONSTANT_P (@var{x}) && GET_CODE (@var{x}) != CONST_DOUBLE)}
-is acceptable, but a few machines are more restrictive as to which
-constant addresses are supported.
-@end defmac
-
-@defmac CONSTANT_P (@var{x})
-@code{CONSTANT_P}, which is defined by target-independent code,
-accepts integer-values expressions whose values are not explicitly
-known, such as @code{symbol_ref}, @code{label_ref}, and @code{high}
-expressions and @code{const} arithmetic expressions, in addition to
-@code{const_int} and @code{const_double} expressions.
-@end defmac
-
-@defmac MAX_REGS_PER_ADDRESS
-A number, the maximum number of registers that can appear in a valid
-memory address. Note that it is up to you to specify a value equal to
-the maximum number that @code{TARGET_LEGITIMATE_ADDRESS_P} would ever
-accept.
-@end defmac
-
-@hook TARGET_LEGITIMATE_ADDRESS_P
-
-@defmac TARGET_MEM_CONSTRAINT
-A single character to be used instead of the default @code{'m'}
-character for general memory addresses. This defines the constraint
-letter which matches the memory addresses accepted by
-@code{TARGET_LEGITIMATE_ADDRESS_P}. Define this macro if you want to
-support new address formats in your back end without changing the
-semantics of the @code{'m'} constraint. This is necessary in order to
-preserve functionality of inline assembly constructs using the
-@code{'m'} constraint.
-@end defmac
-
-@defmac FIND_BASE_TERM (@var{x})
-A C expression to determine the base term of address @var{x},
-or to provide a simplified version of @var{x} from which @file{alias.cc}
-can easily find the base term. This macro is used in only two places:
-@code{find_base_value} and @code{find_base_term} in @file{alias.cc}.
-
-It is always safe for this macro to not be defined. It exists so
-that alias analysis can understand machine-dependent addresses.
-
-The typical use of this macro is to handle addresses containing
-a label_ref or symbol_ref within an UNSPEC@.
-@end defmac
-
-@hook TARGET_LEGITIMIZE_ADDRESS
-
-@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
-A C compound statement that attempts to replace @var{x}, which is an address
-that needs reloading, with a valid memory address for an operand of mode
-@var{mode}. @var{win} will be a C statement label elsewhere in the code.
-It is not necessary to define this macro, but it might be useful for
-performance reasons.
-
-For example, on the i386, it is sometimes possible to use a single
-reload register instead of two by reloading a sum of two pseudo
-registers into a register. On the other hand, for number of RISC
-processors offsets are limited so that often an intermediate address
-needs to be generated in order to address a stack slot. By defining
-@code{LEGITIMIZE_RELOAD_ADDRESS} appropriately, the intermediate addresses
-generated for adjacent some stack slots can be made identical, and thus
-be shared.
-
-@emph{Note}: This macro should be used with caution. It is necessary
-to know something of how reload works in order to effectively use this,
-and it is quite easy to produce macros that build in too much knowledge
-of reload internals.
-
-@emph{Note}: This macro must be able to reload an address created by a
-previous invocation of this macro. If it fails to handle such addresses
-then the compiler may generate incorrect code or abort.
-
-@findex push_reload
-The macro definition should use @code{push_reload} to indicate parts that
-need reloading; @var{opnum}, @var{type} and @var{ind_levels} are usually
-suitable to be passed unaltered to @code{push_reload}.
-
-The code generated by this macro must not alter the substructure of
-@var{x}. If it transforms @var{x} into a more legitimate form, it
-should assign @var{x} (which will always be a C variable) a new value.
-This also applies to parts that you change indirectly by calling
-@code{push_reload}.
-
-@findex strict_memory_address_p
-The macro definition may use @code{strict_memory_address_p} to test if
-the address has become legitimate.
-
-@findex copy_rtx
-If you want to change only a part of @var{x}, one standard way of doing
-this is to use @code{copy_rtx}. Note, however, that it unshares only a
-single level of rtl. Thus, if the part to be changed is not at the
-top level, you'll need to replace first the top level.
-It is not necessary for this macro to come up with a legitimate
-address; but often a machine-dependent strategy can generate better code.
-@end defmac
-
-@hook TARGET_MODE_DEPENDENT_ADDRESS_P
-
-@hook TARGET_LEGITIMATE_CONSTANT_P
-
-@hook TARGET_PRECOMPUTE_TLS_P
-
-@hook TARGET_DELEGITIMIZE_ADDRESS
-
-@hook TARGET_CONST_NOT_OK_FOR_DEBUG_P
-
-@hook TARGET_CANNOT_FORCE_CONST_MEM
-
-@hook TARGET_USE_BLOCKS_FOR_CONSTANT_P
-
-@hook TARGET_USE_BLOCKS_FOR_DECL_P
-
-@hook TARGET_BUILTIN_RECIPROCAL
-
-@hook TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD
-
-@hook TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST
-
-@hook TARGET_VECTORIZE_PREFERRED_VECTOR_ALIGNMENT
-
-@hook TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE
-
-@hook TARGET_VECTORIZE_VEC_PERM_CONST
-
-@hook TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION
-
-@hook TARGET_VECTORIZE_BUILTIN_MD_VECTORIZED_FUNCTION
-
-@hook TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT
-
-@hook TARGET_VECTORIZE_PREFERRED_SIMD_MODE
-
-@hook TARGET_VECTORIZE_SPLIT_REDUCTION
-
-@hook TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_MODES
-
-@hook TARGET_VECTORIZE_RELATED_MODE
-
-@hook TARGET_VECTORIZE_GET_MASK_MODE
-
-@hook TARGET_VECTORIZE_EMPTY_MASK_IS_EXPENSIVE
-
-@hook TARGET_VECTORIZE_CREATE_COSTS
-
-@hook TARGET_VECTORIZE_BUILTIN_GATHER
-
-@hook TARGET_VECTORIZE_BUILTIN_SCATTER
-
-@hook TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN
-
-@hook TARGET_SIMD_CLONE_ADJUST
-
-@hook TARGET_SIMD_CLONE_USABLE
-
-@hook TARGET_SIMT_VF
-
-@hook TARGET_OMP_DEVICE_KIND_ARCH_ISA
-
-@hook TARGET_GOACC_VALIDATE_DIMS
-
-@hook TARGET_GOACC_DIM_LIMIT
-
-@hook TARGET_GOACC_FORK_JOIN
-
-@hook TARGET_GOACC_REDUCTION
-
-@hook TARGET_PREFERRED_ELSE_VALUE
-
-@hook TARGET_GOACC_ADJUST_PRIVATE_DECL
-
-@hook TARGET_GOACC_EXPAND_VAR_DECL
-
-@hook TARGET_GOACC_CREATE_WORKER_BROADCAST_RECORD
-
-@hook TARGET_GOACC_SHARED_MEM_LAYOUT
-
-@node Anchored Addresses
-@section Anchored Addresses
-@cindex anchored addresses
-@cindex @option{-fsection-anchors}
-
-GCC usually addresses every static object as a separate entity.
-For example, if we have:
-
-@smallexample
-static int a, b, c;
-int foo (void) @{ return a + b + c; @}
-@end smallexample
-
-the code for @code{foo} will usually calculate three separate symbolic
-addresses: those of @code{a}, @code{b} and @code{c}. On some targets,
-it would be better to calculate just one symbolic address and access
-the three variables relative to it. The equivalent pseudocode would
-be something like:
-
-@smallexample
-int foo (void)
-@{
- register int *xr = &x;
- return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
-@}
-@end smallexample
-
-(which isn't valid C). We refer to shared addresses like @code{x} as
-``section anchors''. Their use is controlled by @option{-fsection-anchors}.
-
-The hooks below describe the target properties that GCC needs to know
-in order to make effective use of section anchors. It won't use
-section anchors at all unless either @code{TARGET_MIN_ANCHOR_OFFSET}
-or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value.
-
-@hook TARGET_MIN_ANCHOR_OFFSET
-
-@hook TARGET_MAX_ANCHOR_OFFSET
-
-@hook TARGET_ASM_OUTPUT_ANCHOR
-
-@hook TARGET_USE_ANCHORS_FOR_SYMBOL_P
-
-@node Condition Code
-@section Condition Code Status
-@cindex condition code status
-
-Condition codes in GCC are represented as registers,
-which provides better schedulability for
-architectures that do have a condition code register, but on which
-most instructions do not affect it. The latter category includes
-most RISC machines.
-
-Implicit clobbering would pose a strong restriction on the placement of
-the definition and use of the condition code. In the past the definition
-and use were always adjacent. However, recent changes to support trapping
-arithmetic may result in the definition and user being in different blocks.
-Thus, there may be a @code{NOTE_INSN_BASIC_BLOCK} between them. Additionally,
-the definition may be the source of exception handling edges.
-
-These restrictions can prevent important
-optimizations on some machines. For example, on the IBM RS/6000, there
-is a delay for taken branches unless the condition code register is set
-three instructions earlier than the conditional branch. The instruction
-scheduler cannot perform this optimization if it is not permitted to
-separate the definition and use of the condition code register.
-
-If there is a specific
-condition code register in the machine, use a hard register. If the
-condition code or comparison result can be placed in any general register,
-or if there are multiple condition registers, use a pseudo register.
-Registers used to store the condition code value will usually have a mode
-that is in class @code{MODE_CC}.
-
-Alternatively, you can use @code{BImode} if the comparison operator is
-specified already in the compare instruction. In this case, you are not
-interested in most macros in this section.
-
-@menu
-* MODE_CC Condition Codes:: Modern representation of condition codes.
-@end menu
-
-@node MODE_CC Condition Codes
-@subsection Representation of condition codes using registers
-@findex CCmode
-@findex MODE_CC
-
-@defmac SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
-On many machines, the condition code may be produced by other instructions
-than compares, for example the branch can use directly the condition
-code set by a subtract instruction. However, on some machines
-when the condition code is set this way some bits (such as the overflow
-bit) are not set in the same way as a test instruction, so that a different
-branch instruction must be used for some conditional branches. When
-this happens, use the machine mode of the condition code register to
-record different formats of the condition code register. Modes can
-also be used to record which compare instruction (e.g.@: a signed or an
-unsigned comparison) produced the condition codes.
-
-If other modes than @code{CCmode} are required, add them to
-@file{@var{machine}-modes.def} and define @code{SELECT_CC_MODE} to choose
-a mode given an operand of a compare. This is needed because the modes
-have to be chosen not only during RTL generation but also, for example,
-by instruction combination. The result of @code{SELECT_CC_MODE} should
-be consistent with the mode used in the patterns; for example to support
-the case of the add on the SPARC discussed above, we have the pattern
-
-@smallexample
-(define_insn ""
- [(set (reg:CCNZ 0)
- (compare:CCNZ
- (plus:SI (match_operand:SI 0 "register_operand" "%r")
- (match_operand:SI 1 "arith_operand" "rI"))
- (const_int 0)))]
- ""
- "@dots{}")
-@end smallexample
-
-@noindent
-together with a @code{SELECT_CC_MODE} that returns @code{CCNZmode}
-for comparisons whose argument is a @code{plus}:
-
-@smallexample
-#define SELECT_CC_MODE(OP,X,Y) \
- (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \
- ? ((OP == LT || OP == LE || OP == GT || OP == GE) \
- ? CCFPEmode : CCFPmode) \
- : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \
- || GET_CODE (X) == NEG || GET_CODE (x) == ASHIFT) \
- ? CCNZmode : CCmode))
-@end smallexample
-
-Another reason to use modes is to retain information on which operands
-were used by the comparison; see @code{REVERSIBLE_CC_MODE} later in
-this section.
-
-You should define this macro if and only if you define extra CC modes
-in @file{@var{machine}-modes.def}.
-@end defmac
-
-@hook TARGET_CANONICALIZE_COMPARISON
-
-@defmac REVERSIBLE_CC_MODE (@var{mode})
-A C expression whose value is one if it is always safe to reverse a
-comparison whose mode is @var{mode}. If @code{SELECT_CC_MODE}
-can ever return @var{mode} for a floating-point inequality comparison,
-then @code{REVERSIBLE_CC_MODE (@var{mode})} must be zero.
-
-You need not define this macro if it would always returns zero or if the
-floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}.
-For example, here is the definition used on the SPARC, where floating-point
-inequality comparisons are given either @code{CCFPEmode} or @code{CCFPmode}:
-
-@smallexample
-#define REVERSIBLE_CC_MODE(MODE) \
- ((MODE) != CCFPEmode && (MODE) != CCFPmode)
-@end smallexample
-@end defmac
-
-@defmac REVERSE_CONDITION (@var{code}, @var{mode})
-A C expression whose value is reversed condition code of the @var{code} for
-comparison done in CC_MODE @var{mode}. The macro is used only in case
-@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case
-machine has some non-standard way how to reverse certain conditionals. For
-instance in case all floating point conditions are non-trapping, compiler may
-freely convert unordered compares to ordered ones. Then definition may look
-like:
-
-@smallexample
-#define REVERSE_CONDITION(CODE, MODE) \
- ((MODE) != CCFPmode ? reverse_condition (CODE) \
- : reverse_condition_maybe_unordered (CODE))
-@end smallexample
-@end defmac
-
-@hook TARGET_FIXED_CONDITION_CODE_REGS
-
-@hook TARGET_CC_MODES_COMPATIBLE
-
-@hook TARGET_FLAGS_REGNUM
-
-@node Costs
-@section Describing Relative Costs of Operations
-@cindex costs of instructions
-@cindex relative costs
-@cindex speed of instructions
-
-These macros let you describe the relative speed of various operations
-on the target machine.
-
-@defmac REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
-A C expression for the cost of moving data of mode @var{mode} from a
-register in class @var{from} to one in class @var{to}. The classes are
-expressed using the enumeration values such as @code{GENERAL_REGS}. A
-value of 2 is the default; other values are interpreted relative to
-that.
-
-It is not required that the cost always equal 2 when @var{from} is the
-same as @var{to}; on some machines it is expensive to move between
-registers if they are not general registers.
-
-If reload sees an insn consisting of a single @code{set} between two
-hard registers, and if @code{REGISTER_MOVE_COST} applied to their
-classes returns a value of 2, reload does not check to ensure that the
-constraints of the insn are met. Setting a cost of other than 2 will
-allow reload to verify that the constraints are met. You should do this
-if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
-
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_REGISTER_MOVE_COST} instead.
-@end defmac
-
-@hook TARGET_REGISTER_MOVE_COST
-
-@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
-A C expression for the cost of moving data of mode @var{mode} between a
-register of class @var{class} and memory; @var{in} is zero if the value
-is to be written to memory, nonzero if it is to be read in. This cost
-is relative to those in @code{REGISTER_MOVE_COST}. If moving between
-registers and memory is more expensive than between two registers, you
-should define this macro to express the relative cost.
-
-If you do not define this macro, GCC uses a default cost of 4 plus
-the cost of copying via a secondary reload register, if one is
-needed. If your machine requires a secondary reload register to copy
-between memory and a register of @var{class} but the reload mechanism is
-more complex than copying via an intermediate, define this macro to
-reflect the actual cost of the move.
-
-GCC defines the function @code{memory_move_secondary_cost} if
-secondary reloads are needed. It computes the costs due to copying via
-a secondary register. If your machine copies from memory using a
-secondary register in the conventional way but the default base value of
-4 is not correct for your machine, define this macro to add some other
-value to the result of that function. The arguments to that function
-are the same as to this macro.
-
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_MEMORY_MOVE_COST} instead.
-@end defmac
-
-@hook TARGET_MEMORY_MOVE_COST
-
-@defmac BRANCH_COST (@var{speed_p}, @var{predictable_p})
-A C expression for the cost of a branch instruction. A value of 1 is
-the default; other values are interpreted relative to that. Parameter
-@var{speed_p} is true when the branch in question should be optimized
-for speed. When it is false, @code{BRANCH_COST} should return a value
-optimal for code size rather than performance. @var{predictable_p} is
-true for well-predicted branches. On many architectures the
-@code{BRANCH_COST} can be reduced then.
-@end defmac
-
-Here are additional macros which do not specify precise relative costs,
-but only that certain actions are more expensive than GCC would
-ordinarily expect.
-
-@defmac SLOW_BYTE_ACCESS
-Define this macro as a C expression which is nonzero if accessing less
-than a word of memory (i.e.@: a @code{char} or a @code{short}) is no
-faster than accessing a word of memory, i.e., if such access
-require more than one instruction or if there is no difference in cost
-between byte and (aligned) word loads.
-
-When this macro is not defined, the compiler will access a field by
-finding the smallest containing object; when it is defined, a fullword
-load will be used if alignment permits. Unless bytes accesses are
-faster than word accesses, using word accesses is preferable since it
-may eliminate subsequent memory access if subsequent accesses occur to
-other fields in the same word of the structure, but to different bytes.
-@end defmac
-
-@hook TARGET_SLOW_UNALIGNED_ACCESS
-
-@defmac MOVE_RATIO (@var{speed})
-The threshold of number of scalar memory-to-memory move insns, @emph{below}
-which a sequence of insns should be generated instead of a
-string move insn or a library call. Increasing the value will always
-make code faster, but eventually incurs high cost in increased code size.
-
-Note that on machines where the corresponding move insn is a
-@code{define_expand} that emits a sequence of insns, this macro counts
-the number of such sequences.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, a reasonable default is used.
-@end defmac
-
-@hook TARGET_USE_BY_PIECES_INFRASTRUCTURE_P
-
-@hook TARGET_OVERLAP_OP_BY_PIECES_P
-
-@hook TARGET_COMPARE_BY_PIECES_BRANCH_RATIO
-
-@defmac MOVE_MAX_PIECES
-A C expression used by @code{move_by_pieces} to determine the largest unit
-a load or store used to copy memory is. Defaults to @code{MOVE_MAX}.
-@end defmac
-
-@defmac STORE_MAX_PIECES
-A C expression used by @code{store_by_pieces} to determine the largest unit
-a store used to memory is. Defaults to @code{MOVE_MAX_PIECES}, or two times
-the size of @code{HOST_WIDE_INT}, whichever is smaller.
-@end defmac
-
-@defmac COMPARE_MAX_PIECES
-A C expression used by @code{compare_by_pieces} to determine the largest unit
-a load or store used to compare memory is. Defaults to
-@code{MOVE_MAX_PIECES}.
-@end defmac
-
-@defmac CLEAR_RATIO (@var{speed})
-The threshold of number of scalar move insns, @emph{below} which a sequence
-of insns should be generated to clear memory instead of a string clear insn
-or a library call. Increasing the value will always make code faster, but
-eventually incurs high cost in increased code size.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, a reasonable default is used.
-@end defmac
-
-@defmac SET_RATIO (@var{speed})
-The threshold of number of scalar move insns, @emph{below} which a sequence
-of insns should be generated to set memory to a constant value, instead of
-a block set insn or a library call.
-Increasing the value will always make code faster, but
-eventually incurs high cost in increased code size.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, it defaults to the value of @code{MOVE_RATIO}.
-@end defmac
-
-@defmac USE_LOAD_POST_INCREMENT (@var{mode})
-A C expression used to determine whether a load postincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_INCREMENT}.
-@end defmac
-
-@defmac USE_LOAD_POST_DECREMENT (@var{mode})
-A C expression used to determine whether a load postdecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_DECREMENT}.
-@end defmac
-
-@defmac USE_LOAD_PRE_INCREMENT (@var{mode})
-A C expression used to determine whether a load preincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_INCREMENT}.
-@end defmac
-
-@defmac USE_LOAD_PRE_DECREMENT (@var{mode})
-A C expression used to determine whether a load predecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_DECREMENT}.
-@end defmac
-
-@defmac USE_STORE_POST_INCREMENT (@var{mode})
-A C expression used to determine whether a store postincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_INCREMENT}.
-@end defmac
-
-@defmac USE_STORE_POST_DECREMENT (@var{mode})
-A C expression used to determine whether a store postdecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_DECREMENT}.
-@end defmac
-
-@defmac USE_STORE_PRE_INCREMENT (@var{mode})
-This macro is used to determine whether a store preincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_INCREMENT}.
-@end defmac
-
-@defmac USE_STORE_PRE_DECREMENT (@var{mode})
-This macro is used to determine whether a store predecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_DECREMENT}.
-@end defmac
-
-@defmac NO_FUNCTION_CSE
-Define this macro to be true if it is as good or better to call a constant
-function address than to call an address kept in a register.
-@end defmac
-
-@defmac LOGICAL_OP_NON_SHORT_CIRCUIT
-Define this macro if a non-short-circuit operation produced by
-@samp{fold_range_test ()} is optimal. This macro defaults to true if
-@code{BRANCH_COST} is greater than or equal to the value 2.
-@end defmac
-
-@hook TARGET_OPTAB_SUPPORTED_P
-
-@hook TARGET_RTX_COSTS
-
-@hook TARGET_ADDRESS_COST
-
-@hook TARGET_INSN_COST
-
-@hook TARGET_MAX_NOCE_IFCVT_SEQ_COST
-
-@hook TARGET_NOCE_CONVERSION_PROFITABLE_P
-
-@hook TARGET_NEW_ADDRESS_PROFITABLE_P
-
-@hook TARGET_NO_SPECULATION_IN_DELAY_SLOTS_P
-
-@hook TARGET_ESTIMATED_POLY_VALUE
-
-@node Scheduling
-@section Adjusting the Instruction Scheduler
-
-The instruction scheduler may need a fair amount of machine-specific
-adjustment in order to produce good code. GCC provides several target
-hooks for this purpose. It is usually enough to define just a few of
-them: try the first ones in this list first.
-
-@hook TARGET_SCHED_ISSUE_RATE
-
-@hook TARGET_SCHED_VARIABLE_ISSUE
-
-@hook TARGET_SCHED_ADJUST_COST
-
-@hook TARGET_SCHED_ADJUST_PRIORITY
-
-@hook TARGET_SCHED_REORDER
-
-@hook TARGET_SCHED_REORDER2
-
-@hook TARGET_SCHED_MACRO_FUSION_P
-
-@hook TARGET_SCHED_MACRO_FUSION_PAIR_P
-
-@hook TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
-
-@hook TARGET_SCHED_INIT
-
-@hook TARGET_SCHED_FINISH
-
-@hook TARGET_SCHED_INIT_GLOBAL
-
-@hook TARGET_SCHED_FINISH_GLOBAL
-
-@hook TARGET_SCHED_DFA_PRE_CYCLE_INSN
-
-@hook TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN
-
-@hook TARGET_SCHED_DFA_POST_CYCLE_INSN
-
-@hook TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN
-
-@hook TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE
-
-@hook TARGET_SCHED_DFA_POST_ADVANCE_CYCLE
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI
-
-@hook TARGET_SCHED_DFA_NEW_CYCLE
-
-@hook TARGET_SCHED_IS_COSTLY_DEPENDENCE
-
-@hook TARGET_SCHED_H_I_D_EXTENDED
-
-@hook TARGET_SCHED_ALLOC_SCHED_CONTEXT
-
-@hook TARGET_SCHED_INIT_SCHED_CONTEXT
-
-@hook TARGET_SCHED_SET_SCHED_CONTEXT
-
-@hook TARGET_SCHED_CLEAR_SCHED_CONTEXT
-
-@hook TARGET_SCHED_FREE_SCHED_CONTEXT
-
-@hook TARGET_SCHED_SPECULATE_INSN
-
-@hook TARGET_SCHED_NEEDS_BLOCK_P
-
-@hook TARGET_SCHED_GEN_SPEC_CHECK
-
-@hook TARGET_SCHED_SET_SCHED_FLAGS
-
-@hook TARGET_SCHED_CAN_SPECULATE_INSN
-
-@hook TARGET_SCHED_SMS_RES_MII
-
-@hook TARGET_SCHED_DISPATCH
-
-@hook TARGET_SCHED_DISPATCH_DO
-
-@hook TARGET_SCHED_EXPOSED_PIPELINE
-
-@hook TARGET_SCHED_REASSOCIATION_WIDTH
-
-@hook TARGET_SCHED_FUSION_PRIORITY
-
-@hook TARGET_EXPAND_DIVMOD_LIBFUNC
-
-@node Sections
-@section Dividing the Output into Sections (Texts, Data, @dots{})
-@c the above section title is WAY too long. maybe cut the part between
-@c the (...)? --mew 10feb93
-
-An object file is divided into sections containing different types of
-data. In the most common case, there are three sections: the @dfn{text
-section}, which holds instructions and read-only data; the @dfn{data
-section}, which holds initialized writable data; and the @dfn{bss
-section}, which holds uninitialized data. Some systems have other kinds
-of sections.
-
-@file{varasm.cc} provides several well-known sections, such as
-@code{text_section}, @code{data_section} and @code{bss_section}.
-The normal way of controlling a @code{@var{foo}_section} variable
-is to define the associated @code{@var{FOO}_SECTION_ASM_OP} macro,
-as described below. The macros are only read once, when @file{varasm.cc}
-initializes itself, so their values must be run-time constants.
-They may however depend on command-line flags.
-
-@emph{Note:} Some run-time files, such @file{crtstuff.c}, also make
-use of the @code{@var{FOO}_SECTION_ASM_OP} macros, and expect them
-to be string literals.
-
-Some assemblers require a different string to be written every time a
-section is selected. If your assembler falls into this category, you
-should define the @code{TARGET_ASM_INIT_SECTIONS} hook and use
-@code{get_unnamed_section} to set up the sections.
-
-You must always create a @code{text_section}, either by defining
-@code{TEXT_SECTION_ASM_OP} or by initializing @code{text_section}
-in @code{TARGET_ASM_INIT_SECTIONS}. The same is true of
-@code{data_section} and @code{DATA_SECTION_ASM_OP}. If you do not
-create a distinct @code{readonly_data_section}, the default is to
-reuse @code{text_section}.
-
-All the other @file{varasm.cc} sections are optional, and are null
-if the target does not provide them.
-
-@defmac TEXT_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation that should precede instructions and read-only data.
-Normally @code{"\t.text"} is right.
-@end defmac
-
-@defmac HOT_TEXT_SECTION_NAME
-If defined, a C string constant for the name of the section containing most
-frequently executed functions of the program. If not defined, GCC will provide
-a default definition if the target supports named sections.
-@end defmac
-
-@defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME
-If defined, a C string constant for the name of the section containing unlikely
-executed functions in the program.
-@end defmac
-
-@defmac DATA_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation to identify the following data as writable initialized
-data. Normally @code{"\t.data"} is right.
-@end defmac
-
-@defmac SDATA_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-initialized, writable small data.
-@end defmac
-
-@defmac READONLY_DATA_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation to identify the following data as read-only initialized
-data.
-@end defmac
-
-@defmac BSS_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-uninitialized global data. If not defined, and
-@code{ASM_OUTPUT_ALIGNED_BSS} not defined,
-uninitialized global data will be output in the data section if
-@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be
-used.
-@end defmac
-
-@defmac SBSS_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-uninitialized, writable small data.
-@end defmac
-
-@defmac TLS_COMMON_ASM_OP
-If defined, a C expression whose value is a string containing the
-assembler operation to identify the following data as thread-local
-common data. The default is @code{".tls_common"}.
-@end defmac
-
-@defmac TLS_SECTION_ASM_FLAG
-If defined, a C expression whose value is a character constant
-containing the flag used to mark a section as a TLS section. The
-default is @code{'T'}.
-@end defmac
-
-@defmac INIT_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-initialization code. If not defined, GCC will assume such a section does
-not exist. This section has no corresponding @code{init_section}
-variable; it is used entirely in runtime code.
-@end defmac
-
-@defmac FINI_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-finalization code. If not defined, GCC will assume such a section does
-not exist. This section has no corresponding @code{fini_section}
-variable; it is used entirely in runtime code.
-@end defmac
-
-@defmac INIT_ARRAY_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-part of the @code{.init_array} (or equivalent) section. If not
-defined, GCC will assume such a section does not exist. Do not define
-both this macro and @code{INIT_SECTION_ASM_OP}.
-@end defmac
-
-@defmac FINI_ARRAY_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-part of the @code{.fini_array} (or equivalent) section. If not
-defined, GCC will assume such a section does not exist. Do not define
-both this macro and @code{FINI_SECTION_ASM_OP}.
-@end defmac
-
-@defmac MACH_DEP_SECTION_ASM_FLAG
-If defined, a C expression whose value is a character constant
-containing the flag used to mark a machine-dependent section. This
-corresponds to the @code{SECTION_MACH_DEP} section flag.
-@end defmac
-
-@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
-If defined, an ASM statement that switches to a different section
-via @var{section_op}, calls @var{function}, and switches back to
-the text section. This is used in @file{crtstuff.c} if
-@code{INIT_SECTION_ASM_OP} or @code{FINI_SECTION_ASM_OP} to calls
-to initialization and finalization functions from the init and fini
-sections. By default, this macro uses a simple function call. Some
-ports need hand-crafted assembly code to avoid dependencies on
-registers initialized in the function prologue or to ensure that
-constant pools don't end up too far way in the text section.
-@end defmac
-
-@defmac TARGET_LIBGCC_SDATA_SECTION
-If defined, a string which names the section into which small
-variables defined in crtstuff and libgcc should go. This is useful
-when the target has options for optimizing access to small data, and
-you want the crtstuff and libgcc routines to be conservative in what
-they expect of your application yet liberal in what your application
-expects. For example, for targets with a @code{.sdata} section (like
-MIPS), you could compile crtstuff with @code{-G 0} so that it doesn't
-require small data support from your application, but use this macro
-to put small data into @code{.sdata} so that your application can
-access these variables whether it uses small data or not.
-@end defmac
-
-@defmac FORCE_CODE_SECTION_ALIGN
-If defined, an ASM statement that aligns a code section to some
-arbitrary boundary. This is used to force all fragments of the
-@code{.init} and @code{.fini} sections to have to same alignment
-and thus prevent the linker from having to add any padding.
-@end defmac
-
-@defmac JUMP_TABLES_IN_TEXT_SECTION
-Define this macro to be an expression with a nonzero value if jump
-tables (for @code{tablejump} insns) should be output in the text
-section, along with the assembler instructions. Otherwise, the
-readonly data section is used.
-
-This macro is irrelevant if there is no separate readonly data section.
-@end defmac
-
-@hook TARGET_ASM_INIT_SECTIONS
-
-@hook TARGET_ASM_RELOC_RW_MASK
-
-@hook TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC
-
-@hook TARGET_ASM_SELECT_SECTION
-
-@defmac USE_SELECT_SECTION_FOR_FUNCTIONS
-Define this macro if you wish TARGET_ASM_SELECT_SECTION to be called
-for @code{FUNCTION_DECL}s as well as for variables and constants.
-
-In the case of a @code{FUNCTION_DECL}, @var{reloc} will be zero if the
-function has been determined to be likely to be called, and nonzero if
-it is unlikely to be called.
-@end defmac
-
-@hook TARGET_ASM_UNIQUE_SECTION
-
-@hook TARGET_ASM_FUNCTION_RODATA_SECTION
-
-@hook TARGET_ASM_MERGEABLE_RODATA_PREFIX
-
-@hook TARGET_ASM_TM_CLONE_TABLE_SECTION
-
-@hook TARGET_ASM_SELECT_RTX_SECTION
-
-@hook TARGET_MANGLE_DECL_ASSEMBLER_NAME
-
-@hook TARGET_ENCODE_SECTION_INFO
-
-@hook TARGET_STRIP_NAME_ENCODING
-
-@hook TARGET_IN_SMALL_DATA_P
-
-@hook TARGET_HAVE_SRODATA_SECTION
-
-@hook TARGET_PROFILE_BEFORE_PROLOGUE
-
-@hook TARGET_BINDS_LOCAL_P
-
-@hook TARGET_HAVE_TLS
-
-
-@node PIC
-@section Position Independent Code
-@cindex position independent code
-@cindex PIC
-
-This section describes macros that help implement generation of position
-independent code. Simply defining these macros is not enough to
-generate valid PIC; you must also add support to the hook
-@code{TARGET_LEGITIMATE_ADDRESS_P} and to the macro
-@code{PRINT_OPERAND_ADDRESS}, as well as @code{LEGITIMIZE_ADDRESS}. You
-must modify the definition of @samp{movsi} to do something appropriate
-when the source operand contains a symbolic address. You may also
-need to alter the handling of switch statements so that they use
-relative addresses.
-@c i rearranged the order of the macros above to try to force one of
-@c them to the next line, to eliminate an overfull hbox. --mew 10feb93
-
-@defmac PIC_OFFSET_TABLE_REGNUM
-The register number of the register used to address a table of static
-data addresses in memory. In some cases this register is defined by a
-processor's ``application binary interface'' (ABI)@. When this macro
-is defined, RTL is generated for this register once, as with the stack
-pointer and frame pointer registers. If this macro is not defined, it
-is up to the machine-dependent files to allocate such a register (if
-necessary). Note that this register must be fixed when in use (e.g.@:
-when @code{flag_pic} is true).
-@end defmac
-
-@defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-A C expression that is nonzero if the register defined by
-@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls. If not defined,
-the default is zero. Do not define
-this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
-@end defmac
-
-@defmac LEGITIMATE_PIC_OPERAND_P (@var{x})
-A C expression that is nonzero if @var{x} is a legitimate immediate
-operand on the target machine when generating position independent code.
-You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not
-check this. You can also assume @var{flag_pic} is true, so you need not
-check it either. You need not define this macro if all constants
-(including @code{SYMBOL_REF}) can be immediate operands when generating
-position independent code.
-@end defmac
-
-@node Assembler Format
-@section Defining the Output Assembler Language
-
-This section describes macros whose principal purpose is to describe how
-to write instructions in assembler language---rather than what the
-instructions do.
-
-@menu
-* File Framework:: Structural information for the assembler file.
-* Data Output:: Output of constants (numbers, strings, addresses).
-* Uninitialized Data:: Output of uninitialized variables.
-* Label Output:: Output and generation of labels.
-* Initialization:: General principles of initialization
- and termination routines.
-* Macros for Initialization::
- Specific macros that control the handling of
- initialization and termination routines.
-* Instruction Output:: Output of actual instructions.
-* Dispatch Tables:: Output of jump tables.
-* Exception Region Output:: Output of exception region code.
-* Alignment Output:: Pseudo ops for alignment and skipping data.
-@end menu
-
-@node File Framework
-@subsection The Overall Framework of an Assembler File
-@cindex assembler format
-@cindex output of assembler code
-
-@c prevent bad page break with this line
-This describes the overall framework of an assembly file.
-
-@findex default_file_start
-@hook TARGET_ASM_FILE_START
-
-@hook TARGET_ASM_FILE_START_APP_OFF
-
-@hook TARGET_ASM_FILE_START_FILE_DIRECTIVE
-
-@hook TARGET_ASM_FILE_END
-
-@deftypefun void file_end_indicate_exec_stack ()
-Some systems use a common convention, the @samp{.note.GNU-stack}
-special section, to indicate whether or not an object file relies on
-the stack being executable. If your system uses this convention, you
-should define @code{TARGET_ASM_FILE_END} to this function. If you
-need to do other things in that hook, have your hook function call
-this function.
-@end deftypefun
-
-@hook TARGET_ASM_LTO_START
-
-@hook TARGET_ASM_LTO_END
-
-@hook TARGET_ASM_CODE_END
-
-@defmac ASM_COMMENT_START
-A C string constant describing how to begin a comment in the target
-assembler language. The compiler assumes that the comment will end at
-the end of the line.
-@end defmac
-
-@defmac ASM_APP_ON
-A C string constant for text to be output before each @code{asm}
-statement or group of consecutive ones. Normally this is
-@code{"#APP"}, which is a comment that has no effect on most
-assemblers but tells the GNU assembler that it must check the lines
-that follow for all valid assembler constructs.
-@end defmac
-
-@defmac ASM_APP_OFF
-A C string constant for text to be output after each @code{asm}
-statement or group of consecutive ones. Normally this is
-@code{"#NO_APP"}, which tells the GNU assembler to resume making the
-time-saving assumptions that are valid for ordinary compiler output.
-@end defmac
-
-@defmac ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output COFF information or DWARF debugging information
-which indicates that filename @var{name} is the current source file to
-the stdio stream @var{stream}.
-
-This macro need not be defined if the standard form of output
-for the file format in use is appropriate.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_SOURCE_FILENAME
-
-@hook TARGET_ASM_OUTPUT_IDENT
-
-@defmac OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
-A C statement to output the string @var{string} to the stdio stream
-@var{stream}. If you do not call the function @code{output_quoted_string}
-in your config files, GCC will only call it to output filenames to
-the assembler source. So you can use it to canonicalize the format
-of the filename using this macro.
-@end defmac
-
-@hook TARGET_ASM_NAMED_SECTION
-
-@hook TARGET_ASM_ELF_FLAGS_NUMERIC
-
-@hook TARGET_ASM_FUNCTION_SECTION
-
-@hook TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS
-
-@hook TARGET_HAVE_NAMED_SECTIONS
-This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}.
-It must not be modified by command-line option processing.
-@end deftypevr
-
-@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}
-@hook TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
-
-@hook TARGET_SECTION_TYPE_FLAGS
-
-@hook TARGET_ASM_RECORD_GCC_SWITCHES
-
-@hook TARGET_ASM_RECORD_GCC_SWITCHES_SECTION
-
-@need 2000
-@node Data Output
-@subsection Output of Data
-
-
-@hook TARGET_ASM_BYTE_OP
-
-@hook TARGET_ASM_INTEGER
-
-@hook TARGET_ASM_DECL_END
-
-@hook TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA
-
-@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
-A C statement to output to the stdio stream @var{stream} an assembler
-instruction to assemble a string constant containing the @var{len}
-bytes at @var{ptr}. @var{ptr} will be a C expression of type
-@code{char *} and @var{len} a C expression of type @code{int}.
-
-If the assembler has a @code{.ascii} pseudo-op as found in the
-Berkeley Unix assembler, do not define the macro
-@code{ASM_OUTPUT_ASCII}.
-@end defmac
-
-@defmac ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
-A C statement to output word @var{n} of a function descriptor for
-@var{decl}. This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS}
-is defined, and is otherwise unused.
-@end defmac
-
-@defmac CONSTANT_POOL_BEFORE_FUNCTION
-You may define this macro as a C expression. You should define the
-expression to have a nonzero value if GCC should output the constant
-pool for a function before the code for the function, or a zero value if
-GCC should output the constant pool after the function. If you do
-not define this macro, the usual case, GCC will output the constant
-pool before the function.
-@end defmac
-
-@defmac ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
-A C statement to output assembler commands to define the start of the
-constant pool for a function. @var{funname} is a string giving
-the name of the function. Should the return type of the function
-be required, it can be obtained via @var{fundecl}. @var{size}
-is the size, in bytes, of the constant pool that will be written
-immediately after this call.
-
-If no constant-pool prefix is required, the usual case, this macro need
-not be defined.
-@end defmac
-
-@defmac ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
-A C statement (with or without semicolon) to output a constant in the
-constant pool, if it needs special treatment. (This macro need not do
-anything for RTL expressions that can be output normally.)
-
-The argument @var{file} is the standard I/O stream to output the
-assembler code on. @var{x} is the RTL expression for the constant to
-output, and @var{mode} is the machine mode (in case @var{x} is a
-@samp{const_int}). @var{align} is the required alignment for the value
-@var{x}; you should output an assembler directive to force this much
-alignment.
-
-The argument @var{labelno} is a number to use in an internal label for
-the address of this pool entry. The definition of this macro is
-responsible for outputting the label definition at the proper place.
-Here is how to do this:
-
-@smallexample
-@code{(*targetm.asm_out.internal_label)} (@var{file}, "LC", @var{labelno});
-@end smallexample
-
-When you output a pool entry specially, you should end with a
-@code{goto} to the label @var{jumpto}. This will prevent the same pool
-entry from being output a second time in the usual manner.
-
-You need not define this macro if it would do nothing.
-@end defmac
-
-@defmac ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
-A C statement to output assembler commands to at the end of the constant
-pool for a function. @var{funname} is a string giving the name of the
-function. Should the return type of the function be required, you can
-obtain it via @var{fundecl}. @var{size} is the size, in bytes, of the
-constant pool that GCC wrote immediately before this call.
-
-If no constant-pool epilogue is required, the usual case, you need not
-define this macro.
-@end defmac
-
-@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C}, @var{STR})
-Define this macro as a C expression which is nonzero if @var{C} is
-used as a logical line separator by the assembler. @var{STR} points
-to the position in the string where @var{C} was found; this can be used if
-a line separator uses multiple characters.
-
-If you do not define this macro, the default is that only
-the character @samp{;} is treated as a logical line separator.
-@end defmac
-
-@hook TARGET_ASM_OPEN_PAREN
-
-These macros are provided by @file{real.h} for writing the definitions
-of @code{ASM_OUTPUT_DOUBLE} and the like:
-
-@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@var{x}, @var{l})
-These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the
-target's floating point representation, and store its bit pattern in
-the variable @var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE} and
-@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a
-simple @code{long int}. For the others, it should be an array of
-@code{long int}. The number of elements in this array is determined
-by the size of the desired target floating point data type: 32 bits of
-it go in each @code{long int} array element. Each array element holds
-32 bits of the result, even if @code{long int} is wider than 32 bits
-on the host machine.
-
-The array element values are designed so that you can print them out
-using @code{fprintf} in the order they should appear in the target
-machine's memory.
-@end defmac
-
-@node Uninitialized Data
-@subsection Output of Uninitialized Variables
-
-Each of the macros in this section is used to do the whole job of
-outputting a single uninitialized variable.
-
-@defmac ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a common-label named
-@var{name} whose size is @var{size} bytes. The variable @var{rounded}
-is the size rounded up to whatever alignment the caller wants. It is
-possible that @var{size} may be zero, for instance if a struct with no
-other member than a zero-length array is defined. In this case, the
-backend must output a symbol definition that allocates at least one
-byte, both so that the address of the resulting object does not compare
-equal to any other, and because some object formats cannot even express
-the concept of a zero-sized common symbol, as that is how they represent
-an ordinary undefined external.
-
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline.
-
-This macro controls how the assembler definitions of uninitialized
-common global variables are output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a
-separate, explicit argument. If you define this macro, it is used in
-place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in
-handling the required alignment of the variable. The alignment is specified
-as the number of bits.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the
-variable to be output, if there is one, or @code{NULL_TREE} if there
-is no corresponding variable. If you define this macro, GCC will use it
-in place of both @code{ASM_OUTPUT_COMMON} and
-@code{ASM_OUTPUT_ALIGNED_COMMON}. Define this macro when you need to see
-the variable's decl in order to chose what to output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of uninitialized global @var{decl} named
-@var{name} whose size is @var{size} bytes. The variable @var{alignment}
-is the alignment specified as the number of bits.
-
-Try to use function @code{asm_output_aligned_bss} defined in file
-@file{varasm.cc} when defining this macro. If unable, use the expression
-@code{assemble_name (@var{stream}, @var{name})} to output the name itself;
-before and after that, output the additional assembler syntax for defining
-the name, and a newline.
-
-There are two ways of handling global BSS@. One is to define this macro.
-The other is to have @code{TARGET_ASM_SELECT_SECTION} return a
-switchable BSS section (@pxref{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}).
-You do not need to do both.
-
-Some languages do not have @code{common} data, and require a
-non-common form of global BSS in order to handle uninitialized globals
-efficiently. C++ is one example of this. However, if the target does
-not support global BSS, the front end may choose to make globals
-common in order to save space in the object file.
-@end defmac
-
-@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a local-common-label named
-@var{name} whose size is @var{size} bytes. The variable @var{rounded}
-is the size rounded up to whatever alignment the caller wants.
-
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline.
-
-This macro controls how the assembler definitions of uninitialized
-static variables are output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a
-separate, explicit argument. If you define this macro, it is used in
-place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in
-handling the required alignment of the variable. The alignment is specified
-as the number of bits.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_ALIGNED_LOCAL} except that @var{decl} of the
-variable to be output, if there is one, or @code{NULL_TREE} if there
-is no corresponding variable. If you define this macro, GCC will use it
-in place of both @code{ASM_OUTPUT_LOCAL} and
-@code{ASM_OUTPUT_ALIGNED_LOCAL}. Define this macro when you need to see
-the variable's decl in order to chose what to output.
-@end defmac
-
-@node Label Output
-@subsection Output and Generation of Labels
-
-@c prevent bad page break with this line
-This is about outputting labels.
-
-@findex assemble_name
-@defmac ASM_OUTPUT_LABEL (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a label named @var{name}.
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline. A default
-definition of this macro is provided which is correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_FUNCTION_LABEL (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a label named @var{name} of
-a function.
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline. A default
-definition of this macro is provided which is correct for most systems.
-
-If this macro is not defined, then the function name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-@end defmac
-
-@findex assemble_name_raw
-@defmac ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{name})
-Identical to @code{ASM_OUTPUT_LABEL}, except that @var{name} is known
-to refer to a compiler-generated label. The default definition uses
-@code{assemble_name_raw}, which is like @code{assemble_name} except
-that it is more efficient.
-@end defmac
-
-@defmac SIZE_ASM_OP
-A C string containing the appropriate assembler directive to specify the
-size of a symbol, without any arguments. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"\t.size\t"}; on other
-systems, the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definitions
-of @code{ASM_OUTPUT_SIZE_DIRECTIVE} and @code{ASM_OUTPUT_MEASURED_SIZE}
-for your system. If you need your own custom definitions of those
-macros, or if you do not need explicit symbol sizes at all, do not
-define this macro.
-@end defmac
-
-@defmac ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler that the size of the
-symbol @var{name} is @var{size}. @var{size} is a @code{HOST_WIDE_INT}.
-If you define @code{SIZE_ASM_OP}, a default definition of this macro is
-provided.
-@end defmac
-
-@defmac ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler to calculate the size of
-the symbol @var{name} by subtracting its address from the current
-address.
-
-If you define @code{SIZE_ASM_OP}, a default definition of this macro is
-provided. The default assumes that the assembler recognizes a special
-@samp{.} symbol as referring to the current address, and can calculate
-the difference between this and another symbol. If your assembler does
-not recognize @samp{.} or cannot do calculations with it, you will need
-to redefine @code{ASM_OUTPUT_MEASURED_SIZE} to use some other technique.
-@end defmac
-
-@defmac NO_DOLLAR_IN_LABEL
-Define this macro if the assembler does not accept the character
-@samp{$} in label names. By default constructors and destructors in
-G++ have @samp{$} in the identifiers. If this macro is defined,
-@samp{.} is used instead.
-@end defmac
-
-@defmac NO_DOT_IN_LABEL
-Define this macro if the assembler does not accept the character
-@samp{.} in label names. By default constructors and destructors in G++
-have names that use @samp{.}. If this macro is defined, these names
-are rewritten to avoid @samp{.}.
-@end defmac
-
-@defmac TYPE_ASM_OP
-A C string containing the appropriate assembler directive to specify the
-type of a symbol, without any arguments. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"\t.type\t"}; on other
-systems, the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definition of
-@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
-custom definition of this macro, or if you do not need explicit symbol
-types at all, do not define this macro.
-@end defmac
-
-@defmac TYPE_OPERAND_FMT
-A C string which specifies (using @code{printf} syntax) the format of
-the second operand to @code{TYPE_ASM_OP}. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"@@%s"}; on other systems,
-the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definition of
-@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
-custom definition of this macro, or if you do not need explicit symbol
-types at all, do not define this macro.
-@end defmac
-
-@defmac ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler that the type of the
-symbol @var{name} is @var{type}. @var{type} is a C string; currently,
-that string is always either @samp{"function"} or @samp{"object"}, but
-you should not count on this.
-
-If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
-definition of this macro is provided.
-@end defmac
-
-@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of a
-function which is being defined. This macro is responsible for
-outputting the label definition (perhaps using
-@code{ASM_OUTPUT_FUNCTION_LABEL}). The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the function name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_FUNCTION_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the size of a function
-which is being defined. The argument @var{name} is the name of the
-function. The argument @var{decl} is the @code{FUNCTION_DECL} tree node
-representing the function.
-
-If this macro is not defined, then the function size is not defined.
-
-You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_COLD_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of a
-cold function partition which is being defined. This macro is responsible
-for outputting the label definition (perhaps using
-@code{ASM_OUTPUT_FUNCTION_LABEL}). The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the cold partition name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_COLD_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the size of a cold function
-partition which is being defined. The argument @var{name} is the name of the
-cold partition of the function. The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the partition size is not defined.
-
-You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of an
-initialized variable which is being defined. This macro must output the
-label definition (perhaps using @code{ASM_OUTPUT_LABEL}). The argument
-@var{decl} is the @code{VAR_DECL} tree node representing the variable.
-
-If this macro is not defined, then the variable name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} and/or
-@code{ASM_OUTPUT_SIZE_DIRECTIVE} in the definition of this macro.
-@end defmac
-
-@hook TARGET_ASM_DECLARE_CONSTANT_NAME
-
-@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for claiming a register @var{regno}
-for a global variable @var{decl} with name @var{name}.
-
-If you don't define this macro, that is equivalent to defining it to do
-nothing.
-@end defmac
-
-@defmac ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
-A C statement (sans semicolon) to finish up declaring a variable name
-once the compiler has processed its initializer fully and thus has had a
-chance to determine the size of an array when controlled by an
-initializer. This is used on systems where it's necessary to declare
-something about the size of the object.
-
-If you don't define this macro, that is equivalent to defining it to do
-nothing.
-
-You may wish to use @code{ASM_OUTPUT_SIZE_DIRECTIVE} and/or
-@code{ASM_OUTPUT_MEASURED_SIZE} in the definition of this macro.
-@end defmac
-
-@hook TARGET_ASM_GLOBALIZE_LABEL
-
-@hook TARGET_ASM_GLOBALIZE_DECL_NAME
-
-@hook TARGET_ASM_ASSEMBLE_UNDEFINED_DECL
-
-@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} some commands that will make the label @var{name} weak;
-that is, available for reference from other files but only used if
-no other definition is available. Use the expression
-@code{assemble_name (@var{stream}, @var{name})} to output the name
-itself; before and after that, output the additional assembler syntax
-for making that name weak, and a newline.
-
-If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not
-support weak symbols and you should not define the @code{SUPPORTS_WEAK}
-macro.
-@end defmac
-
-@defmac ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
-Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and
-@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function
-or variable decl. If @var{value} is not @code{NULL}, this C statement
-should output to the stdio stream @var{stream} assembler code which
-defines (equates) the weak symbol @var{name} to have the value
-@var{value}. If @var{value} is @code{NULL}, it should output commands
-to make @var{name} weak.
-@end defmac
-
-@defmac ASM_OUTPUT_WEAKREF (@var{stream}, @var{decl}, @var{name}, @var{value})
-Outputs a directive that enables @var{name} to be used to refer to
-symbol @var{value} with weak-symbol semantics. @code{decl} is the
-declaration of @code{name}.
-@end defmac
-
-@defmac SUPPORTS_WEAK
-A preprocessor constant expression which evaluates to true if the target
-supports weak symbols.
-
-If you don't define this macro, @file{defaults.h} provides a default
-definition. If either @code{ASM_WEAKEN_LABEL} or @code{ASM_WEAKEN_DECL}
-is defined, the default definition is @samp{1}; otherwise, it is @samp{0}.
-@end defmac
-
-@defmac TARGET_SUPPORTS_WEAK
-A C expression which evaluates to true if the target supports weak symbols.
-
-If you don't define this macro, @file{defaults.h} provides a default
-definition. The default definition is @samp{(SUPPORTS_WEAK)}. Define
-this macro if you want to control weak symbol support with a compiler
-flag such as @option{-melf}.
-@end defmac
-
-@defmac MAKE_DECL_ONE_ONLY (@var{decl})
-A C statement (sans semicolon) to mark @var{decl} to be emitted as a
-public symbol such that extra copies in multiple translation units will
-be discarded by the linker. Define this macro if your object file
-format provides support for this concept, such as the @samp{COMDAT}
-section flags in the Microsoft Windows PE/COFF format, and this support
-requires changes to @var{decl}, such as putting it in a separate section.
-@end defmac
-
-@defmac SUPPORTS_ONE_ONLY
-A C expression which evaluates to true if the target supports one-only
-semantics.
-
-If you don't define this macro, @file{varasm.cc} provides a default
-definition. If @code{MAKE_DECL_ONE_ONLY} is defined, the default
-definition is @samp{1}; otherwise, it is @samp{0}. Define this macro if
-you want to control one-only symbol support with a compiler flag, or if
-setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to
-be emitted as one-only.
-@end defmac
-
-@hook TARGET_ASM_ASSEMBLE_VISIBILITY
-
-@defmac TARGET_WEAK_NOT_IN_ARCHIVE_TOC
-A C expression that evaluates to true if the target's linker expects
-that weak symbols do not appear in a static archive's table of contents.
-The default is @code{0}.
-
-Leaving weak symbols out of an archive's table of contents means that,
-if a symbol will only have a definition in one translation unit and
-will have undefined references from other translation units, that
-symbol should not be weak. Defining this macro to be nonzero will
-thus have the effect that certain symbols that would normally be weak
-(explicit template instantiations, and vtables for polymorphic classes
-with noninline key methods) will instead be nonweak.
-
-The C++ ABI requires this macro to be zero. Define this macro for
-targets where full C++ ABI compliance is impossible and where linker
-restrictions require weak symbols to be left out of a static archive's
-table of contents.
-@end defmac
-
-@defmac ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name of an external
-symbol named @var{name} which is referenced in this compilation but
-not defined. The value of @var{decl} is the tree node for the
-declaration.
-
-This macro need not be defined if it does not need to output anything.
-The GNU assembler and most Unix assemblers don't require anything.
-@end defmac
-
-@hook TARGET_ASM_EXTERNAL_LIBCALL
-
-@hook TARGET_ASM_MARK_DECL_PRESERVED
-
-@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a reference in assembler syntax to a label named
-@var{name}. This should add @samp{_} to the front of the name, if that
-is customary on your operating system, as it is in most Berkeley Unix
-systems. This macro is used in @code{assemble_name}.
-@end defmac
-
-@hook TARGET_MANGLE_ASSEMBLER_NAME
-
-@defmac ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
-A C statement (sans semicolon) to output a reference to
-@code{SYMBOL_REF} @var{sym}. If not defined, @code{assemble_name}
-will be used to output the name of the symbol. This macro may be used
-to modify the way a symbol is referenced depending on information
-encoded by @code{TARGET_ENCODE_SECTION_INFO}.
-@end defmac
-
-@defmac ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
-A C statement (sans semicolon) to output a reference to @var{buf}, the
-result of @code{ASM_GENERATE_INTERNAL_LABEL}. If not defined,
-@code{assemble_name} will be used to output the name of the symbol.
-This macro is not used by @code{output_asm_label}, or the @code{%l}
-specifier that calls it; the intention is that this macro should be set
-when it is necessary to output a label differently when its address is
-being taken.
-@end defmac
-
-@hook TARGET_ASM_INTERNAL_LABEL
-
-@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
-A C statement to output to the stdio stream @var{stream} a debug info
-label whose name is made from the string @var{prefix} and the number
-@var{num}. This is useful for VLIW targets, where debug info labels
-may need to be treated differently than branch target labels. On some
-systems, branch target labels must be at the beginning of instruction
-bundles, but debug info labels can occur in the middle of instruction
-bundles.
-
-If this macro is not defined, then @code{(*targetm.asm_out.internal_label)} will be
-used.
-@end defmac
-
-@defmac ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
-A C statement to store into the string @var{string} a label whose name
-is made from the string @var{prefix} and the number @var{num}.
-
-This string, when output subsequently by @code{assemble_name}, should
-produce the output that @code{(*targetm.asm_out.internal_label)} would produce
-with the same @var{prefix} and @var{num}.
-
-If the string begins with @samp{*}, then @code{assemble_name} will
-output the rest of the string unchanged. It is often convenient for
-@code{ASM_GENERATE_INTERNAL_LABEL} to use @samp{*} in this way. If the
-string doesn't start with @samp{*}, then @code{ASM_OUTPUT_LABELREF} gets
-to output the string, and may change it. (Of course,
-@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so
-you should know what it does on your machine.)
-@end defmac
-
-@defmac ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
-A C expression to assign to @var{outvar} (which is a variable of type
-@code{char *}) a newly allocated string made from the string
-@var{name} and the number @var{number}, with some suitable punctuation
-added. Use @code{alloca} to get space for the string.
-
-The string will be used as an argument to @code{ASM_OUTPUT_LABELREF} to
-produce an assembler label for an internal static variable whose name is
-@var{name}. Therefore, the string must be such as to result in valid
-assembler code. The argument @var{number} is different each time this
-macro is executed; it prevents conflicts between similarly-named
-internal static variables in different scopes.
-
-Ideally this string should not be a valid C identifier, to prevent any
-conflict with the user's own symbols. Most assemblers allow periods
-or percent signs in assembler symbols; putting at least one of these
-between the name and the number will suffice.
-
-If this macro is not defined, a default definition will be provided
-which is correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the symbol @var{name} to have the value @var{value}.
-
-@findex SET_ASM_OP
-If @code{SET_ASM_OP} is defined, a default definition is provided which is
-correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the symbol whose tree node is @var{decl_of_name}
-to have the value of the tree node @var{decl_of_value}. This macro will
-be used in preference to @samp{ASM_OUTPUT_DEF} if it is defined and if
-the tree nodes are available.
-
-@findex SET_ASM_OP
-If @code{SET_ASM_OP} is defined, a default definition is provided which is
-correct for most systems.
-@end defmac
-
-@defmac TARGET_DEFERRED_OUTPUT_DEFS (@var{decl_of_name}, @var{decl_of_value})
-A C statement that evaluates to true if the assembler code which defines
-(equates) the symbol whose tree node is @var{decl_of_name} to have the value
-of the tree node @var{decl_of_value} should be emitted near the end of the
-current compilation unit. The default is to not defer output of defines.
-This macro affects defines output by @samp{ASM_OUTPUT_DEF} and
-@samp{ASM_OUTPUT_DEF_FROM_DECLS}.
-@end defmac
-
-@defmac ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the weak symbol @var{name} to have the value
-@var{value}. If @var{value} is @code{NULL}, it defines @var{name} as
-an undefined weak symbol.
-
-Define this macro if the target only supports weak aliases; define
-@code{ASM_OUTPUT_DEF} instead if possible.
-@end defmac
-
-@defmac OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
-Define this macro to override the default assembler names used for
-Objective-C methods.
-
-The default name is a unique method number followed by the name of the
-class (e.g.@: @samp{_1_Foo}). For methods in categories, the name of
-the category is also included in the assembler name (e.g.@:
-@samp{_1_Foo_Bar}).
-
-These names are safe on most systems, but make debugging difficult since
-the method's selector is not present in the name. Therefore, particular
-systems define other ways of computing names.
-
-@var{buf} is an expression of type @code{char *} which gives you a
-buffer in which to store the name; its length is as long as
-@var{class_name}, @var{cat_name} and @var{sel_name} put together, plus
-50 characters extra.
-
-The argument @var{is_inst} specifies whether the method is an instance
-method or a class method; @var{class_name} is the name of the class;
-@var{cat_name} is the name of the category (or @code{NULL} if the method is not
-in a category); and @var{sel_name} is the name of the selector.
-
-On systems where the assembler can handle quoted names, you can use this
-macro to provide more human-readable names.
-@end defmac
-
-@node Initialization
-@subsection How Initialization Functions Are Handled
-@cindex initialization routines
-@cindex termination routines
-@cindex constructors, output of
-@cindex destructors, output of
-
-The compiled code for certain languages includes @dfn{constructors}
-(also called @dfn{initialization routines})---functions to initialize
-data in the program when the program is started. These functions need
-to be called before the program is ``started''---that is to say, before
-@code{main} is called.
-
-Compiling some languages generates @dfn{destructors} (also called
-@dfn{termination routines}) that should be called when the program
-terminates.
-
-To make the initialization and termination functions work, the compiler
-must output something in the assembler code to cause those functions to
-be called at the appropriate time. When you port the compiler to a new
-system, you need to specify how to do this.
-
-There are two major ways that GCC currently supports the execution of
-initialization and termination functions. Each way has two variants.
-Much of the structure is common to all four variations.
-
-@findex __CTOR_LIST__
-@findex __DTOR_LIST__
-The linker must build two lists of these functions---a list of
-initialization functions, called @code{__CTOR_LIST__}, and a list of
-termination functions, called @code{__DTOR_LIST__}.
-
-Each list always begins with an ignored function pointer (which may hold
-0, @minus{}1, or a count of the function pointers after it, depending on
-the environment). This is followed by a series of zero or more function
-pointers to constructors (or destructors), followed by a function
-pointer containing zero.
-
-Depending on the operating system and its executable file format, either
-@file{crtstuff.c} or @file{libgcc2.c} traverses these lists at startup
-time and exit time. Constructors are called in reverse order of the
-list; destructors in forward order.
-
-The best way to handle static constructors works only for object file
-formats which provide arbitrarily-named sections. A section is set
-aside for a list of constructors, and another for a list of destructors.
-Traditionally these are called @samp{.ctors} and @samp{.dtors}. Each
-object file that defines an initialization function also puts a word in
-the constructor section to point to that function. The linker
-accumulates all these words into one contiguous @samp{.ctors} section.
-Termination functions are handled similarly.
-
-This method will be chosen as the default by @file{target-def.h} if
-@code{TARGET_ASM_NAMED_SECTION} is defined. A target that does not
-support arbitrary sections, but does support special designated
-constructor and destructor sections may define @code{CTORS_SECTION_ASM_OP}
-and @code{DTORS_SECTION_ASM_OP} to achieve the same effect.
-
-When arbitrary sections are available, there are two variants, depending
-upon how the code in @file{crtstuff.c} is called. On systems that
-support a @dfn{.init} section which is executed at program startup,
-parts of @file{crtstuff.c} are compiled into that section. The
-program is linked by the @command{gcc} driver like this:
-
-@smallexample
-ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o
-@end smallexample
-
-The prologue of a function (@code{__init}) appears in the @code{.init}
-section of @file{crti.o}; the epilogue appears in @file{crtn.o}. Likewise
-for the function @code{__fini} in the @dfn{.fini} section. Normally these
-files are provided by the operating system or by the GNU C library, but
-are provided by GCC for a few targets.
-
-The objects @file{crtbegin.o} and @file{crtend.o} are (for most targets)
-compiled from @file{crtstuff.c}. They contain, among other things, code
-fragments within the @code{.init} and @code{.fini} sections that branch
-to routines in the @code{.text} section. The linker will pull all parts
-of a section together, which results in a complete @code{__init} function
-that invokes the routines we need at startup.
-
-To use this variant, you must define the @code{INIT_SECTION_ASM_OP}
-macro properly.
-
-If no init section is available, when GCC compiles any function called
-@code{main} (or more accurately, any function designated as a program
-entry point by the language front end calling @code{expand_main_function}),
-it inserts a procedure call to @code{__main} as the first executable code
-after the function prologue. The @code{__main} function is defined
-in @file{libgcc2.c} and runs the global constructors.
-
-In file formats that don't support arbitrary sections, there are again
-two variants. In the simplest variant, the GNU linker (GNU @code{ld})
-and an `a.out' format must be used. In this case,
-@code{TARGET_ASM_CONSTRUCTOR} is defined to produce a @code{.stabs}
-entry of type @samp{N_SETT}, referencing the name @code{__CTOR_LIST__},
-and with the address of the void function containing the initialization
-code as its value. The GNU linker recognizes this as a request to add
-the value to a @dfn{set}; the values are accumulated, and are eventually
-placed in the executable as a vector in the format described above, with
-a leading (ignored) count and a trailing zero element.
-@code{TARGET_ASM_DESTRUCTOR} is handled similarly. Since no init
-section is available, the absence of @code{INIT_SECTION_ASM_OP} causes
-the compilation of @code{main} to call @code{__main} as above, starting
-the initialization process.
-
-The last variant uses neither arbitrary sections nor the GNU linker.
-This is preferable when you want to do dynamic linking and when using
-file formats which the GNU linker does not support, such as `ECOFF'@. In
-this case, @code{TARGET_HAVE_CTORS_DTORS} is false, initialization and
-termination functions are recognized simply by their names. This requires
-an extra program in the linkage step, called @command{collect2}. This program
-pretends to be the linker, for use with GCC; it does its job by running
-the ordinary linker, but also arranges to include the vectors of
-initialization and termination functions. These functions are called
-via @code{__main} as described above. In order to use this method,
-@code{use_collect2} must be defined in the target in @file{config.gcc}.
-
-@ifinfo
-The following section describes the specific macros that control and
-customize the handling of initialization and termination functions.
-@end ifinfo
-
-@node Macros for Initialization
-@subsection Macros Controlling Initialization Routines
-
-Here are the macros that control how the compiler handles initialization
-and termination functions:
-
-@defmac INIT_SECTION_ASM_OP
-If defined, a C string constant, including spacing, for the assembler
-operation to identify the following data as initialization code. If not
-defined, GCC will assume such a section does not exist. When you are
-using special sections for initialization and termination functions, this
-macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to
-run the initialization functions.
-@end defmac
-
-@defmac HAS_INIT_SECTION
-If defined, @code{main} will not call @code{__main} as described above.
-This macro should be defined for systems that control start-up code
-on a symbol-by-symbol basis, such as OSF/1, and should not
-be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}.
-@end defmac
-
-@defmac LD_INIT_SWITCH
-If defined, a C string constant for a switch that tells the linker that
-the following symbol is an initialization routine.
-@end defmac
-
-@defmac LD_FINI_SWITCH
-If defined, a C string constant for a switch that tells the linker that
-the following symbol is a finalization routine.
-@end defmac
-
-@defmac COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
-If defined, a C statement that will write a function that can be
-automatically called when a shared library is loaded. The function
-should call @var{func}, which takes no arguments. If not defined, and
-the object format requires an explicit initialization function, then a
-function called @code{_GLOBAL__DI} will be generated.
-
-This function and the following one are used by collect2 when linking a
-shared library that needs constructors or destructors, or has DWARF2
-exception tables embedded in the code.
-@end defmac
-
-@defmac COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
-If defined, a C statement that will write a function that can be
-automatically called when a shared library is unloaded. The function
-should call @var{func}, which takes no arguments. If not defined, and
-the object format requires an explicit finalization function, then a
-function called @code{_GLOBAL__DD} will be generated.
-@end defmac
-
-@defmac INVOKE__main
-If defined, @code{main} will call @code{__main} despite the presence of
-@code{INIT_SECTION_ASM_OP}. This macro should be defined for systems
-where the init section is not actually run automatically, but is still
-useful for collecting the lists of constructors and destructors.
-@end defmac
-
-@defmac SUPPORTS_INIT_PRIORITY
-If nonzero, the C++ @code{init_priority} attribute is supported and the
-compiler should emit instructions to control the order of initialization
-of objects. If zero, the compiler will issue an error message upon
-encountering an @code{init_priority} attribute.
-@end defmac
-
-@hook TARGET_HAVE_CTORS_DTORS
-
-@hook TARGET_DTORS_FROM_CXA_ATEXIT
-
-@hook TARGET_ASM_CONSTRUCTOR
-
-@hook TARGET_ASM_DESTRUCTOR
-
-If @code{TARGET_HAVE_CTORS_DTORS} is true, the initialization routine
-generated for the generated object file will have static linkage.
-
-If your system uses @command{collect2} as the means of processing
-constructors, then that program normally uses @command{nm} to scan
-an object file for constructor functions to be called.
-
-On certain kinds of systems, you can define this macro to make
-@command{collect2} work faster (and, in some cases, make it work at all):
-
-@defmac OBJECT_FORMAT_COFF
-Define this macro if the system uses COFF (Common Object File Format)
-object files, so that @command{collect2} can assume this format and scan
-object files directly for dynamic constructor/destructor functions.
-
-This macro is effective only in a native compiler; @command{collect2} as
-part of a cross compiler always uses @command{nm} for the target machine.
-@end defmac
-
-@defmac REAL_NM_FILE_NAME
-Define this macro as a C string constant containing the file name to use
-to execute @command{nm}. The default is to search the path normally for
-@command{nm}.
-@end defmac
-
-@defmac NM_FLAGS
-@command{collect2} calls @command{nm} to scan object files for static
-constructors and destructors and LTO info. By default, @option{-n} is
-passed. Define @code{NM_FLAGS} to a C string constant if other options
-are needed to get the same output format as GNU @command{nm -n}
-produces.
-@end defmac
-
-If your system supports shared libraries and has a program to list the
-dynamic dependencies of a given library or executable, you can define
-these macros to enable support for running initialization and
-termination functions in shared libraries:
-
-@defmac LDD_SUFFIX
-Define this macro to a C string constant containing the name of the program
-which lists dynamic dependencies, like @command{ldd} under SunOS 4.
-@end defmac
-
-@defmac PARSE_LDD_OUTPUT (@var{ptr})
-Define this macro to be C code that extracts filenames from the output
-of the program denoted by @code{LDD_SUFFIX}. @var{ptr} is a variable
-of type @code{char *} that points to the beginning of a line of output
-from @code{LDD_SUFFIX}. If the line lists a dynamic dependency, the
-code must advance @var{ptr} to the beginning of the filename on that
-line. Otherwise, it must set @var{ptr} to @code{NULL}.
-@end defmac
-
-@defmac SHLIB_SUFFIX
-Define this macro to a C string constant containing the default shared
-library extension of the target (e.g., @samp{".so"}). @command{collect2}
-strips version information after this suffix when generating global
-constructor and destructor names. This define is only needed on targets
-that use @command{collect2} to process constructors and destructors.
-@end defmac
-
-@node Instruction Output
-@subsection Output of Assembler Instructions
-
-@c prevent bad page break with this line
-This describes assembler instruction output.
-
-@defmac REGISTER_NAMES
-A C initializer containing the assembler's names for the machine
-registers, each one as a C string constant. This is what translates
-register numbers in the compiler into assembler language.
-@end defmac
-
-@defmac ADDITIONAL_REGISTER_NAMES
-If defined, a C initializer for an array of structures containing a name
-and a register number. This macro defines additional names for hard
-registers, thus allowing the @code{asm} option in declarations to refer
-to registers using alternate names.
-@end defmac
-
-@defmac OVERLAPPING_REGISTER_NAMES
-If defined, a C initializer for an array of structures containing a
-name, a register number and a count of the number of consecutive
-machine registers the name overlaps. This macro defines additional
-names for hard registers, thus allowing the @code{asm} option in
-declarations to refer to registers using alternate names. Unlike
-@code{ADDITIONAL_REGISTER_NAMES}, this macro should be used when the
-register name implies multiple underlying registers.
-
-This macro should be used when it is important that a clobber in an
-@code{asm} statement clobbers all the underlying values implied by the
-register name. For example, on ARM, clobbering the double-precision
-VFP register ``d0'' implies clobbering both single-precision registers
-``s0'' and ``s1''.
-@end defmac
-
-@defmac ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
-Define this macro if you are using an unusual assembler that
-requires different names for the machine instructions.
-
-The definition is a C statement or statements which output an
-assembler instruction opcode to the stdio stream @var{stream}. The
-macro-operand @var{ptr} is a variable of type @code{char *} which
-points to the opcode name in its ``internal'' form---the form that is
-written in the machine description. The definition should output the
-opcode name to @var{stream}, performing any translation you desire, and
-increment the variable @var{ptr} to point at the end of the opcode
-so that it will not be output twice.
-
-In fact, your macro definition may process less than the entire opcode
-name, or more than the opcode name; but if you want to process text
-that includes @samp{%}-sequences to substitute operands, you must take
-care of the substitution yourself. Just be sure to increment
-@var{ptr} over whatever text should not be output normally.
-
-@findex recog_data.operand
-If you need to look at the operand values, they can be found as the
-elements of @code{recog_data.operand}.
-
-If the macro definition does nothing, the instruction is output
-in the usual way.
-@end defmac
-
-@defmac FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
-If defined, a C statement to be executed just prior to the output of
-assembler code for @var{insn}, to modify the extracted operands so
-they will be output differently.
-
-Here the argument @var{opvec} is the vector containing the operands
-extracted from @var{insn}, and @var{noperands} is the number of
-elements of the vector which contain meaningful data for this insn.
-The contents of this vector are what will be used to convert the insn
-template into assembler code, so you can change the assembler output
-by changing the contents of the vector.
-
-This macro is useful when various assembler syntaxes share a single
-file of instruction patterns; by defining this macro differently, you
-can cause a large class of instructions to be output differently (such
-as with rearranged operands). Naturally, variations in assembler
-syntax affecting individual insn patterns ought to be handled by
-writing conditional output routines in those patterns.
-
-If this macro is not defined, it is equivalent to a null statement.
-@end defmac
-
-@hook TARGET_ASM_FINAL_POSTSCAN_INSN
-
-@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
-A C compound statement to output to stdio stream @var{stream} the
-assembler syntax for an instruction operand @var{x}. @var{x} is an
-RTL expression.
-
-@var{code} is a value that can be used to specify one of several ways
-of printing the operand. It is used when identical operands must be
-printed differently depending on the context. @var{code} comes from
-the @samp{%} specification that was used to request printing of the
-operand. If the specification was just @samp{%@var{digit}} then
-@var{code} is 0; if the specification was @samp{%@var{ltr}
-@var{digit}} then @var{code} is the ASCII code for @var{ltr}.
-
-@findex reg_names
-If @var{x} is a register, this macro should print the register's name.
-The names can be found in an array @code{reg_names} whose type is
-@code{char *[]}. @code{reg_names} is initialized from
-@code{REGISTER_NAMES}.
-
-When the machine description has a specification @samp{%@var{punct}}
-(a @samp{%} followed by a punctuation character), this macro is called
-with a null pointer for @var{x} and the punctuation character for
-@var{code}.
-@end defmac
-
-@defmac PRINT_OPERAND_PUNCT_VALID_P (@var{code})
-A C expression which evaluates to true if @var{code} is a valid
-punctuation character for use in the @code{PRINT_OPERAND} macro. If
-@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no
-punctuation characters (except for the standard one, @samp{%}) are used
-in this way.
-@end defmac
-
-@defmac PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
-A C compound statement to output to stdio stream @var{stream} the
-assembler syntax for an instruction operand that is a memory reference
-whose address is @var{x}. @var{x} is an RTL expression.
-
-@cindex @code{TARGET_ENCODE_SECTION_INFO} usage
-On some machines, the syntax for a symbolic address depends on the
-section that the address refers to. On these machines, define the hook
-@code{TARGET_ENCODE_SECTION_INFO} to store the information into the
-@code{symbol_ref}, and then check for it here. @xref{Assembler
-Format}.
-@end defmac
-
-@findex dbr_sequence_length
-@defmac DBR_OUTPUT_SEQEND (@var{file})
-A C statement, to be executed after all slot-filler instructions have
-been output. If necessary, call @code{dbr_sequence_length} to
-determine the number of slots filled in a sequence (zero if not
-currently outputting a sequence), to decide how many no-ops to output,
-or whatever.
-
-Don't define this macro if it has nothing to do, but it is helpful in
-reading assembly output if the extent of the delay sequence is made
-explicit (e.g.@: with white space).
-@end defmac
-
-@findex final_sequence
-Note that output routines for instructions with delay slots must be
-prepared to deal with not being output as part of a sequence
-(i.e.@: when the scheduling pass is not run, or when no slot fillers could be
-found.) The variable @code{final_sequence} is null when not
-processing a sequence, otherwise it contains the @code{sequence} rtx
-being output.
-
-@findex asm_fprintf
-@defmac REGISTER_PREFIX
-@defmacx LOCAL_LABEL_PREFIX
-@defmacx USER_LABEL_PREFIX
-@defmacx IMMEDIATE_PREFIX
-If defined, C string expressions to be used for the @samp{%R}, @samp{%L},
-@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see
-@file{final.cc}). These are useful when a single @file{md} file must
-support multiple assembler formats. In that case, the various @file{tm.h}
-files can define these macros differently.
-@end defmac
-
-@defmac ASM_FPRINTF_EXTENSIONS (@var{file}, @var{argptr}, @var{format})
-If defined this macro should expand to a series of @code{case}
-statements which will be parsed inside the @code{switch} statement of
-the @code{asm_fprintf} function. This allows targets to define extra
-printf formats which may useful when generating their assembler
-statements. Note that uppercase letters are reserved for future
-generic extensions to asm_fprintf, and so are not available to target
-specific code. The output file is given by the parameter @var{file}.
-The varargs input pointer is @var{argptr} and the rest of the format
-string, starting the character after the one that is being switched
-upon, is pointed to by @var{format}.
-@end defmac
-
-@defmac ASSEMBLER_DIALECT
-If your target supports multiple dialects of assembler language (such as
-different opcodes), define this macro as a C expression that gives the
-numeric index of the assembler language dialect to use, with zero as the
-first variant.
-
-If this macro is defined, you may use constructs of the form
-@smallexample
-@samp{@{option0|option1|option2@dots{}@}}
-@end smallexample
-@noindent
-in the output templates of patterns (@pxref{Output Template}) or in the
-first argument of @code{asm_fprintf}. This construct outputs
-@samp{option0}, @samp{option1}, @samp{option2}, etc., if the value of
-@code{ASSEMBLER_DIALECT} is zero, one, two, etc. Any special characters
-within these strings retain their usual meaning. If there are fewer
-alternatives within the braces than the value of
-@code{ASSEMBLER_DIALECT}, the construct outputs nothing. If it's needed
-to print curly braces or @samp{|} character in assembler output directly,
-@samp{%@{}, @samp{%@}} and @samp{%|} can be used.
-
-If you do not define this macro, the characters @samp{@{}, @samp{|} and
-@samp{@}} do not have any special meaning when used in templates or
-operands to @code{asm_fprintf}.
-
-Define the macros @code{REGISTER_PREFIX}, @code{LOCAL_LABEL_PREFIX},
-@code{USER_LABEL_PREFIX} and @code{IMMEDIATE_PREFIX} if you can express
-the variations in assembler language syntax with that mechanism. Define
-@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax
-if the syntax variant are larger and involve such things as different
-opcodes or operand order.
-@end defmac
-
-@defmac ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
-A C expression to output to @var{stream} some assembler code
-which will push hard register number @var{regno} onto the stack.
-The code need not be optimal, since this macro is used only when
-profiling.
-@end defmac
-
-@defmac ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
-A C expression to output to @var{stream} some assembler code
-which will pop hard register number @var{regno} off of the stack.
-The code need not be optimal, since this macro is used only when
-profiling.
-@end defmac
-
-@node Dispatch Tables
-@subsection Output of Dispatch Tables
-
-@c prevent bad page break with this line
-This concerns dispatch tables.
-
-@cindex dispatch table
-@defmac ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
-A C statement to output to the stdio stream @var{stream} an assembler
-pseudo-instruction to generate a difference between two labels.
-@var{value} and @var{rel} are the numbers of two internal labels. The
-definitions of these labels are output using
-@code{(*targetm.asm_out.internal_label)}, and they must be printed in the same
-way here. For example,
-
-@smallexample
-fprintf (@var{stream}, "\t.word L%d-L%d\n",
- @var{value}, @var{rel})
-@end smallexample
-
-You must provide this macro on machines where the addresses in a
-dispatch table are relative to the table's own address. If defined, GCC
-will also use this macro on all machines when producing PIC@.
-@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the
-mode and flags can be read.
-@end defmac
-
-@defmac ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
-This macro should be provided on machines where the addresses
-in a dispatch table are absolute.
-
-The definition should be a C statement to output to the stdio stream
-@var{stream} an assembler pseudo-instruction to generate a reference to
-a label. @var{value} is the number of an internal label whose
-definition is output using @code{(*targetm.asm_out.internal_label)}.
-For example,
-
-@smallexample
-fprintf (@var{stream}, "\t.word L%d\n", @var{value})
-@end smallexample
-@end defmac
-
-@defmac ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
-Define this if the label before a jump-table needs to be output
-specially. The first three arguments are the same as for
-@code{(*targetm.asm_out.internal_label)}; the fourth argument is the
-jump-table which follows (a @code{jump_table_data} containing an
-@code{addr_vec} or @code{addr_diff_vec}).
-
-This feature is used on system V to output a @code{swbeg} statement
-for the table.
-
-If this macro is not defined, these labels are output with
-@code{(*targetm.asm_out.internal_label)}.
-@end defmac
-
-@defmac ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
-Define this if something special must be output at the end of a
-jump-table. The definition should be a C statement to be executed
-after the assembler code for the table is written. It should write
-the appropriate code to stdio stream @var{stream}. The argument
-@var{table} is the jump-table insn, and @var{num} is the label-number
-of the preceding label.
-
-If this macro is not defined, nothing special is output at the end of
-the jump-table.
-@end defmac
-
-@hook TARGET_ASM_POST_CFI_STARTPROC
-
-@hook TARGET_ASM_EMIT_UNWIND_LABEL
-
-@hook TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL
-
-@hook TARGET_ASM_EMIT_EXCEPT_PERSONALITY
-
-@hook TARGET_ASM_UNWIND_EMIT
-
-@hook TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT
-
-@hook TARGET_ASM_UNWIND_EMIT_BEFORE_INSN
-
-@hook TARGET_ASM_SHOULD_RESTORE_CFA_STATE
-
-@node Exception Region Output
-@subsection Assembler Commands for Exception Regions
-
-@c prevent bad page break with this line
-
-This describes commands marking the start and the end of an exception
-region.
-
-@defmac EH_FRAME_SECTION_NAME
-If defined, a C string constant for the name of the section containing
-exception handling frame unwind information. If not defined, GCC will
-provide a default definition if the target supports named sections.
-@file{crtstuff.c} uses this macro to switch to the appropriate section.
-
-You should define this symbol if your target supports DWARF 2 frame
-unwind information and the default definition does not work.
-@end defmac
-
-@defmac EH_FRAME_THROUGH_COLLECT2
-If defined, DWARF 2 frame unwind information will identified by
-specially named labels. The collect2 process will locate these
-labels and generate code to register the frames.
-
-This might be necessary, for instance, if the system linker will not
-place the eh_frames in-between the sentinals from @file{crtstuff.c},
-or if the system linker does garbage collection and sections cannot
-be marked as not to be collected.
-@end defmac
-
-@defmac EH_TABLES_CAN_BE_READ_ONLY
-Define this macro to 1 if your target is such that no frame unwind
-information encoding used with non-PIC code will ever require a
-runtime relocation, but the linker may not support merging read-only
-and read-write sections into a single read-write section.
-@end defmac
-
-@defmac MASK_RETURN_ADDR
-An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so
-that it does not contain any extraneous set bits in it.
-@end defmac
-
-@defmac DWARF2_UNWIND_INFO
-Define this macro to 0 if your target supports DWARF 2 frame unwind
-information, but it does not yet work with exception handling.
-Otherwise, if your target supports this information (if it defines
-@code{INCOMING_RETURN_ADDR_RTX} and @code{OBJECT_FORMAT_ELF}),
-GCC will provide a default definition of 1.
-@end defmac
-
-@hook TARGET_EXCEPT_UNWIND_INFO
-This hook defines the mechanism that will be used for exception handling
-by the target. If the target has ABI specified unwind tables, the hook
-should return @code{UI_TARGET}. If the target is to use the
-@code{setjmp}/@code{longjmp}-based exception handling scheme, the hook
-should return @code{UI_SJLJ}. If the target supports DWARF 2 frame unwind
-information, the hook should return @code{UI_DWARF2}.
-
-A target may, if exceptions are disabled, choose to return @code{UI_NONE}.
-This may end up simplifying other parts of target-specific code. The
-default implementation of this hook never returns @code{UI_NONE}.
-
-Note that the value returned by this hook should be constant. It should
-not depend on anything except the command-line switches described by
-@var{opts}. In particular, the
-setting @code{UI_SJLJ} must be fixed at compiler start-up as C pre-processor
-macros and builtin functions related to exception handling are set up
-depending on this setting.
-
-The default implementation of the hook first honors the
-@option{--enable-sjlj-exceptions} configure option, then
-@code{DWARF2_UNWIND_INFO}, and finally defaults to @code{UI_SJLJ}. If
-@code{DWARF2_UNWIND_INFO} depends on command-line options, the target
-must define this hook so that @var{opts} is used correctly.
-@end deftypefn
-
-@hook TARGET_UNWIND_TABLES_DEFAULT
-This variable should be set to @code{true} if the target ABI requires unwinding
-tables even when exceptions are not used. It must not be modified by
-command-line option processing.
-@end deftypevr
-
-@defmac DONT_USE_BUILTIN_SETJMP
-Define this macro to 1 if the @code{setjmp}/@code{longjmp}-based scheme
-should use the @code{setjmp}/@code{longjmp} functions from the C library
-instead of the @code{__builtin_setjmp}/@code{__builtin_longjmp} machinery.
-@end defmac
-
-@defmac JMP_BUF_SIZE
-This macro has no effect unless @code{DONT_USE_BUILTIN_SETJMP} is also
-defined. Define this macro if the default size of @code{jmp_buf} buffer
-for the @code{setjmp}/@code{longjmp}-based exception handling mechanism
-is not large enough, or if it is much too large.
-The default size is @code{FIRST_PSEUDO_REGISTER * sizeof(void *)}.
-@end defmac
-
-@defmac DWARF_CIE_DATA_ALIGNMENT
-This macro need only be defined if the target might save registers in the
-function prologue at an offset to the stack pointer that is not aligned to
-@code{UNITS_PER_WORD}. The definition should be the negative minimum
-alignment if @code{STACK_GROWS_DOWNWARD} is true, and the positive
-minimum alignment otherwise. @xref{DWARF}. Only applicable if
-the target supports DWARF 2 frame unwind information.
-@end defmac
-
-@hook TARGET_TERMINATE_DW2_EH_FRAME_INFO
-
-@hook TARGET_DWARF_REGISTER_SPAN
-
-@hook TARGET_DWARF_FRAME_REG_MODE
-
-@hook TARGET_INIT_DWARF_REG_SIZES_EXTRA
-
-@hook TARGET_ASM_TTYPE
-
-@hook TARGET_ARM_EABI_UNWINDER
-
-@node Alignment Output
-@subsection Assembler Commands for Alignment
-
-@c prevent bad page break with this line
-This describes commands for alignment.
-
-@defmac JUMP_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label}, which is
-a common destination of jumps and has no fallthru incoming edge.
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @var{align_jumps} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation.
-@end defmac
-
-@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label})
-The alignment (log base 2) to put in front of @var{label}, which follows
-a @code{BARRIER}.
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-@end defmac
-
-@defmac LOOP_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label} that heads
-a frequently executed basic block (usually the header of a loop).
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @code{align_loops} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation.
-@end defmac
-
-@defmac LABEL_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label}.
-If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment,
-the maximum of the specified values is used.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @code{align_labels} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation.
-@end defmac
-
-@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
-A C statement to output to the stdio stream @var{stream} an assembler
-instruction to advance the location counter by @var{nbytes} bytes.
-Those bytes should be zero when loaded. @var{nbytes} will be a C
-expression of type @code{unsigned HOST_WIDE_INT}.
-@end defmac
-
-@defmac ASM_NO_SKIP_IN_TEXT
-Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the
-text section because it fails to put zeros in the bytes that are skipped.
-This is true on many Unix systems, where the pseudo--op to skip bytes
-produces no-op instructions rather than zeros when used in the text
-section.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
-A C statement to output to the stdio stream @var{stream} an assembler
-command to advance the location counter to a multiple of 2 to the
-@var{power} bytes. @var{power} will be a C expression of type @code{int}.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGN_WITH_NOP (@var{stream}, @var{power})
-Like @code{ASM_OUTPUT_ALIGN}, except that the ``nop'' instruction is used
-for padding, if necessary.
-@end defmac
-
-@defmac ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
-A C statement to output to the stdio stream @var{stream} an assembler
-command to advance the location counter to a multiple of 2 to the
-@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to
-satisfy the alignment request. @var{power} and @var{max_skip} will be
-a C expression of type @code{int}.
-@end defmac
-
-@need 3000
-@node Debugging Info
-@section Controlling Debugging Information Format
-
-@c prevent bad page break with this line
-This describes how to specify debugging information.
-
-@menu
-* All Debuggers:: Macros that affect all debugging formats uniformly.
-* DBX Options:: Macros enabling specific options in DBX format.
-* DBX Hooks:: Hook macros for varying DBX format.
-* File Names and DBX:: Macros controlling output of file names in DBX format.
-* DWARF:: Macros for DWARF format.
-* VMS Debug:: Macros for VMS debug format.
-* CTF Debug:: Macros for CTF debug format.
-* BTF Debug:: Macros for BTF debug format.
-@end menu
-
-@node All Debuggers
-@subsection Macros Affecting All Debugging Formats
-
-@c prevent bad page break with this line
-These macros affect all debugging formats.
-
-@defmac DBX_REGISTER_NUMBER (@var{regno})
-A C expression that returns the DBX register number for the compiler
-register number @var{regno}. In the default macro provided, the value
-of this expression will be @var{regno} itself. But sometimes there are
-some registers that the compiler knows about and DBX does not, or vice
-versa. In such cases, some register may need to have one number in the
-compiler and another for DBX@.
-
-If two registers have consecutive numbers inside GCC, and they can be
-used as a pair to hold a multiword value, then they @emph{must} have
-consecutive numbers after renumbering with @code{DBX_REGISTER_NUMBER}.
-Otherwise, debuggers will be unable to access such a pair, because they
-expect register pairs to be consecutive in their own numbering scheme.
-
-If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that
-does not preserve register pairs, then what you must do instead is
-redefine the actual register numbering scheme.
-@end defmac
-
-@defmac DEBUGGER_AUTO_OFFSET (@var{x})
-A C expression that returns the integer offset value for an automatic
-variable having address @var{x} (an RTL expression). The default
-computation assumes that @var{x} is based on the frame-pointer and
-gives the offset from the frame-pointer. This is required for targets
-that produce debugging output for DBX and allow the frame-pointer to be
-eliminated when the @option{-g} option is used.
-@end defmac
-
-@defmac DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
-A C expression that returns the integer offset value for an argument
-having address @var{x} (an RTL expression). The nominal offset is
-@var{offset}.
-@end defmac
-
-@defmac PREFERRED_DEBUGGING_TYPE
-A C expression that returns the type of debugging output GCC should
-produce when the user specifies just @option{-g}. Define
-this if you have arranged for GCC to support more than one format of
-debugging output. Currently, the allowable values are @code{DBX_DEBUG},
-@code{DWARF2_DEBUG}, @code{XCOFF_DEBUG}, @code{VMS_DEBUG},
-and @code{VMS_AND_DWARF2_DEBUG}.
-
-When the user specifies @option{-ggdb}, GCC normally also uses the
-value of this macro to select the debugging output format, but with two
-exceptions. If @code{DWARF2_DEBUGGING_INFO} is defined, GCC uses the
-value @code{DWARF2_DEBUG}. Otherwise, if @code{DBX_DEBUGGING_INFO} is
-defined, GCC uses @code{DBX_DEBUG}.
-
-The value of this macro only affects the default debugging output; the
-user can always get a specific type of output by using @option{-gstabs},
-@option{-gdwarf-2}, @option{-gxcoff}, or @option{-gvms}.
-@end defmac
-
-@node DBX Options
-@subsection Specific Options for DBX Output
-
-@c prevent bad page break with this line
-These are specific options for DBX output.
-
-@defmac DBX_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output for DBX
-in response to the @option{-g} option.
-@end defmac
-
-@defmac XCOFF_DEBUGGING_INFO
-Define this macro if GCC should produce XCOFF format debugging output
-in response to the @option{-g} option. This is a variant of DBX format.
-@end defmac
-
-@defmac DEFAULT_GDB_EXTENSIONS
-Define this macro to control whether GCC should by default generate
-GDB's extended version of DBX debugging information (assuming DBX-format
-debugging information is enabled at all). If you don't define the
-macro, the default is 1: always generate the extended information
-if there is any occasion to.
-@end defmac
-
-@defmac DEBUG_SYMS_TEXT
-Define this macro if all @code{.stabs} commands should be output while
-in the text section.
-@end defmac
-
-@defmac ASM_STABS_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol.
-If you don't define this macro, @code{"\t.stabs\t"} is used. This macro
-applies only to DBX debugging information format.
-@end defmac
-
-@defmac ASM_STABD_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabd\t"} to define a debugging symbol whose
-value is the current location. If you don't define this macro,
-@code{"\t.stabd\t"} is used. This macro applies only to DBX debugging
-information format.
-@end defmac
-
-@defmac ASM_STABN_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabn\t"} to define a debugging symbol with no
-name. If you don't define this macro, @code{"\t.stabn\t"} is used. This
-macro applies only to DBX debugging information format.
-@end defmac
-
-@defmac DBX_NO_XREFS
-Define this macro if DBX on your system does not support the construct
-@samp{xs@var{tagname}}. On some systems, this construct is used to
-describe a forward reference to a structure named @var{tagname}.
-On other systems, this construct is not supported at all.
-@end defmac
-
-@defmac DBX_CONTIN_LENGTH
-A symbol name in DBX-format debugging information is normally
-continued (split into two separate @code{.stabs} directives) when it
-exceeds a certain length (by default, 80 characters). On some
-operating systems, DBX requires this splitting; on others, splitting
-must not be done. You can inhibit splitting by defining this macro
-with the value zero. You can override the default splitting-length by
-defining this macro as an expression for the length you desire.
-@end defmac
-
-@defmac DBX_CONTIN_CHAR
-Normally continuation is indicated by adding a @samp{\} character to
-the end of a @code{.stabs} string when a continuation follows. To use
-a different character instead, define this macro as a character
-constant for the character you want to use. Do not define this macro
-if backslash is correct for your system.
-@end defmac
-
-@defmac DBX_STATIC_STAB_DATA_SECTION
-Define this macro if it is necessary to go to the data section before
-outputting the @samp{.stabs} pseudo-op for a non-global static
-variable.
-@end defmac
-
-@defmac DBX_TYPE_DECL_STABS_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a typedef. The default is @code{N_LSYM}.
-@end defmac
-
-@defmac DBX_STATIC_CONST_VAR_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a static variable located in the text section. DBX format does not
-provide any ``right'' way to do this. The default is @code{N_FUN}.
-@end defmac
-
-@defmac DBX_REGPARM_STABS_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a parameter passed in registers. DBX format does not provide any
-``right'' way to do this. The default is @code{N_RSYM}.
-@end defmac
-
-@defmac DBX_REGPARM_STABS_LETTER
-The letter to use in DBX symbol data to identify a symbol as a parameter
-passed in registers. DBX format does not customarily provide any way to
-do this. The default is @code{'P'}.
-@end defmac
-
-@defmac DBX_FUNCTION_FIRST
-Define this macro if the DBX information for a function and its
-arguments should precede the assembler code for the function. Normally,
-in DBX format, the debugging information entirely follows the assembler
-code.
-@end defmac
-
-@defmac DBX_BLOCKS_FUNCTION_RELATIVE
-Define this macro, with value 1, if the value of a symbol describing
-the scope of a block (@code{N_LBRAC} or @code{N_RBRAC}) should be
-relative to the start of the enclosing function. Normally, GCC uses
-an absolute address.
-@end defmac
-
-@defmac DBX_LINES_FUNCTION_RELATIVE
-Define this macro, with value 1, if the value of a symbol indicating
-the current line number (@code{N_SLINE}) should be relative to the
-start of the enclosing function. Normally, GCC uses an absolute address.
-@end defmac
-
-@defmac DBX_USE_BINCL
-Define this macro if GCC should generate @code{N_BINCL} and
-@code{N_EINCL} stabs for included header files, as on Sun systems. This
-macro also directs GCC to output a type number as a pair of a file
-number and a type number within the file. Normally, GCC does not
-generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single
-number for a type number.
-@end defmac
-
-@node DBX Hooks
-@subsection Open-Ended Hooks for DBX Format
-
-@c prevent bad page break with this line
-These are hooks for DBX format.
-
-@defmac DBX_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}, @var{counter})
-A C statement to output DBX debugging information before code for line
-number @var{line} of the current source file to the stdio stream
-@var{stream}. @var{counter} is the number of time the macro was
-invoked, including the current invocation; it is intended to generate
-unique labels in the assembly output.
-
-This macro should not be defined if the default output is correct, or
-if it can be made correct by defining @code{DBX_LINES_FUNCTION_RELATIVE}.
-@end defmac
-
-@defmac NO_DBX_FUNCTION_END
-Some stabs encapsulation formats (in particular ECOFF), cannot handle the
-@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct.
-On those machines, define this macro to turn this feature off without
-disturbing the rest of the gdb extensions.
-@end defmac
-
-@defmac NO_DBX_BNSYM_ENSYM
-Some assemblers cannot handle the @code{.stabd BNSYM/ENSYM,0,0} gdb dbx
-extension construct. On those machines, define this macro to turn this
-feature off without disturbing the rest of the gdb extensions.
-@end defmac
-
-@node File Names and DBX
-@subsection File Names in DBX Format
-
-@c prevent bad page break with this line
-This describes file names in DBX format.
-
-@defmac DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output DBX debugging information to the stdio stream
-@var{stream}, which indicates that file @var{name} is the main source
-file---the file specified as the input file for compilation.
-This macro is called only once, at the beginning of compilation.
-
-This macro need not be defined if the standard form of output
-for DBX debugging information is appropriate.
-
-It may be necessary to refer to a label equal to the beginning of the
-text section. You can use @samp{assemble_name (stream, ltext_label_name)}
-to do so. If you do this, you must also set the variable
-@var{used_ltext_label_name} to @code{true}.
-@end defmac
-
-@defmac NO_DBX_MAIN_SOURCE_DIRECTORY
-Define this macro, with value 1, if GCC should not emit an indication
-of the current directory for compilation and current source language at
-the beginning of the file.
-@end defmac
-
-@defmac NO_DBX_GCC_MARKER
-Define this macro, with value 1, if GCC should not emit an indication
-that this object file was compiled by GCC@. The default is to emit
-an @code{N_OPT} stab at the beginning of every source file, with
-@samp{gcc2_compiled.} for the string and value 0.
-@end defmac
-
-@defmac DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
-A C statement to output DBX debugging information at the end of
-compilation of the main source file @var{name}. Output should be
-written to the stdio stream @var{stream}.
-
-If you don't define this macro, nothing special is output at the end
-of compilation, which is correct for most machines.
-@end defmac
-
-@defmac DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END
-Define this macro @emph{instead of} defining
-@code{DBX_OUTPUT_MAIN_SOURCE_FILE_END}, if what needs to be output at
-the end of compilation is an @code{N_SO} stab with an empty string,
-whose value is the highest absolute text address in the file.
-@end defmac
-
-@need 2000
-@node DWARF
-@subsection Macros for DWARF Output
-
-@c prevent bad page break with this line
-Here are macros for DWARF output.
-
-@defmac DWARF2_DEBUGGING_INFO
-Define this macro if GCC should produce dwarf version 2 format
-debugging output in response to the @option{-g} option.
-
-@hook TARGET_DWARF_CALLING_CONVENTION
-
-To support optional call frame debugging information, you must also
-define @code{INCOMING_RETURN_ADDR_RTX} and either set
-@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the
-prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save}
-as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't.
-@end defmac
-
-@defmac DWARF2_FRAME_INFO
-Define this macro to a nonzero value if GCC should always output
-Dwarf 2 frame information. If @code{TARGET_EXCEPT_UNWIND_INFO}
-(@pxref{Exception Region Output}) returns @code{UI_DWARF2}, and
-exceptions are enabled, GCC will output this information not matter
-how you define @code{DWARF2_FRAME_INFO}.
-@end defmac
-
-@hook TARGET_DEBUG_UNWIND_INFO
-
-@defmac DWARF2_ASM_LINE_DEBUG_INFO
-Define this macro to be a nonzero value if the assembler can generate Dwarf 2
-line debug info sections. This will result in much more compact line number
-tables, and hence is desirable if it works.
-@end defmac
-
-@defmac DWARF2_ASM_VIEW_DEBUG_INFO
-Define this macro to be a nonzero value if the assembler supports view
-assignment and verification in @code{.loc}. If it does not, but the
-user enables location views, the compiler may have to fallback to
-internal line number tables.
-@end defmac
-
-@hook TARGET_RESET_LOCATION_VIEW
-
-@hook TARGET_WANT_DEBUG_PUB_SECTIONS
-
-@hook TARGET_DELAY_SCHED2
-
-@hook TARGET_DELAY_VARTRACK
-
-@hook TARGET_NO_REGISTER_ALLOCATION
-
-@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
-A C statement to issue assembly directives that create a difference
-@var{lab1} minus @var{lab2}, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_VMS_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
-A C statement to issue assembly directives that create a difference
-between the two given labels in system defined units, e.g.@: instruction
-slots on IA64 VMS, using an integer of the given size.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label}, @var{offset}, @var{section})
-A C statement to issue assembly directives that create a
-section-relative reference to the given @var{label} plus @var{offset}, using
-an integer of the given @var{size}. The label is known to be defined in the
-given @var{section}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
-A C statement to issue assembly directives that create a self-relative
-reference to the given @var{label}, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_DATAREL (@var{stream}, @var{size}, @var{label})
-A C statement to issue assembly directives that create a reference to the
-given @var{label} relative to the dbase, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_TABLE_REF (@var{label})
-A C statement to issue assembly directives that create a reference to
-the DWARF table identifier @var{label} from the current section. This
-is used on some systems to avoid garbage collecting a DWARF table which
-is referenced by a function.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_DWARF_DTPREL
-
-@need 2000
-@node VMS Debug
-@subsection Macros for VMS Debug Format
-
-@c prevent bad page break with this line
-Here are macros for VMS debug format.
-
-@defmac VMS_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output for VMS
-in response to the @option{-g} option. The default behavior for VMS
-is to generate minimal debug info for a traceback in the absence of
-@option{-g} unless explicitly overridden with @option{-g0}. This
-behavior is controlled by @code{TARGET_OPTION_OPTIMIZATION} and
-@code{TARGET_OPTION_OVERRIDE}.
-@end defmac
-
-@need 2000
-@node CTF Debug
-@subsection Macros for CTF Debug Format
-
-@c prevent bad page break with this line
-Here are macros for CTF debug format.
-
-@defmac CTF_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output in CTF debug
-format in response to the @option{-gctf} option.
-@end defmac
-
-@need 2000
-@node BTF Debug
-@subsection Macros for BTF Debug Format
-
-@c prevent bad page break with this line
-Here are macros for BTF debug format.
-
-@defmac BTF_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output in BTF debug
-format in response to the @option{-gbtf} option.
-@end defmac
-
-@node Floating Point
-@section Cross Compilation and Floating Point
-@cindex cross compilation and floating point
-@cindex floating point and cross compilation
-
-While all modern machines use twos-complement representation for integers,
-there are a variety of representations for floating point numbers. This
-means that in a cross-compiler the representation of floating point numbers
-in the compiled program may be different from that used in the machine
-doing the compilation.
-
-Because different representation systems may offer different amounts of
-range and precision, all floating point constants must be represented in
-the target machine's format. Therefore, the cross compiler cannot
-safely use the host machine's floating point arithmetic; it must emulate
-the target's arithmetic. To ensure consistency, GCC always uses
-emulation to work with floating point values, even when the host and
-target floating point formats are identical.
-
-The following macros are provided by @file{real.h} for the compiler to
-use. All parts of the compiler which generate or optimize
-floating-point calculations must use these macros. They may evaluate
-their operands more than once, so operands must not have side effects.
-
-@defmac REAL_VALUE_TYPE
-The C data type to be used to hold a floating point value in the target
-machine's format. Typically this is a @code{struct} containing an
-array of @code{HOST_WIDE_INT}, but all code should treat it as an opaque
-quantity.
-@end defmac
-
-@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x})
-Truncates @var{x} to a signed integer, rounding toward zero.
-@end deftypefn
-
-@deftypefn Macro {unsigned HOST_WIDE_INT} REAL_VALUE_UNSIGNED_FIX (REAL_VALUE_TYPE @var{x})
-Truncates @var{x} to an unsigned integer, rounding toward zero. If
-@var{x} is negative, returns zero.
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, machine_mode @var{mode})
-Converts @var{string} into a floating point number in the target machine's
-representation for mode @var{mode}. This routine can handle both
-decimal and hexadecimal floating point constants, using the syntax
-defined by the C language for both.
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE @var{x})
-Returns 1 if @var{x} is negative (including negative zero), 0 otherwise.
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_ISINF (REAL_VALUE_TYPE @var{x})
-Determines whether @var{x} represents infinity (positive or negative).
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_ISNAN (REAL_VALUE_TYPE @var{x})
-Determines whether @var{x} represents a ``NaN'' (not-a-number).
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE @var{x})
-Returns the negative of the floating point value @var{x}.
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE @var{x})
-Returns the absolute value of @var{x}.
-@end deftypefn
-
-@node Mode Switching
-@section Mode Switching Instructions
-@cindex mode switching
-The following macros control mode switching optimizations:
-
-@defmac OPTIMIZE_MODE_SWITCHING (@var{entity})
-Define this macro if the port needs extra instructions inserted for mode
-switching in an optimizing compilation.
-
-For an example, the SH4 can perform both single and double precision
-floating point operations, but to perform a single precision operation,
-the FPSCR PR bit has to be cleared, while for a double precision
-operation, this bit has to be set. Changing the PR bit requires a general
-purpose register as a scratch register, hence these FPSCR sets have to
-be inserted before reload, i.e.@: you cannot put this into instruction emitting
-or @code{TARGET_MACHINE_DEPENDENT_REORG}.
-
-You can have multiple entities that are mode-switched, and select at run time
-which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should
-return nonzero for any @var{entity} that needs mode-switching.
-If you define this macro, you also have to define
-@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{TARGET_MODE_NEEDED},
-@code{TARGET_MODE_PRIORITY} and @code{TARGET_MODE_EMIT}.
-@code{TARGET_MODE_AFTER}, @code{TARGET_MODE_ENTRY}, and @code{TARGET_MODE_EXIT}
-are optional.
-@end defmac
-
-@defmac NUM_MODES_FOR_MODE_SWITCHING
-If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as
-initializer for an array of integers. Each initializer element
-N refers to an entity that needs mode switching, and specifies the number
-of different modes that might need to be set for this entity.
-The position of the initializer in the initializer---starting counting at
-zero---determines the integer that is used to refer to the mode-switched
-entity in question.
-In macros that take mode arguments / yield a mode result, modes are
-represented as numbers 0 @dots{} N @minus{} 1. N is used to specify that no mode
-switch is needed / supplied.
-@end defmac
-
-@hook TARGET_MODE_EMIT
-
-@hook TARGET_MODE_NEEDED
-
-@hook TARGET_MODE_AFTER
-
-@hook TARGET_MODE_ENTRY
-
-@hook TARGET_MODE_EXIT
-
-@hook TARGET_MODE_PRIORITY
-
-@node Target Attributes
-@section Defining target-specific uses of @code{__attribute__}
-@cindex target attributes
-@cindex machine attributes
-@cindex attributes, target-specific
-
-Target-specific attributes may be defined for functions, data and types.
-These are described using the following target hooks; they also need to
-be documented in @file{extend.texi}.
-
-@hook TARGET_ATTRIBUTE_TABLE
-
-@hook TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P
-
-@hook TARGET_COMP_TYPE_ATTRIBUTES
-
-@hook TARGET_SET_DEFAULT_TYPE_ATTRIBUTES
-
-@hook TARGET_MERGE_TYPE_ATTRIBUTES
-
-@hook TARGET_MERGE_DECL_ATTRIBUTES
-
-@hook TARGET_VALID_DLLIMPORT_ATTRIBUTE_P
-
-@defmac TARGET_DECLSPEC
-Define this macro to a nonzero value if you want to treat
-@code{__declspec(X)} as equivalent to @code{__attribute((X))}. By
-default, this behavior is enabled only for targets that define
-@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}. The current implementation
-of @code{__declspec} is via a built-in macro, but you should not rely
-on this implementation detail.
-@end defmac
-
-@hook TARGET_INSERT_ATTRIBUTES
-
-@hook TARGET_HANDLE_GENERIC_ATTRIBUTE
-
-@hook TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P
-
-@hook TARGET_OPTION_VALID_ATTRIBUTE_P
-
-@hook TARGET_OPTION_SAVE
-
-@hook TARGET_OPTION_RESTORE
-
-@hook TARGET_OPTION_POST_STREAM_IN
-
-@hook TARGET_OPTION_PRINT
-
-@hook TARGET_OPTION_PRAGMA_PARSE
-
-@hook TARGET_OPTION_OVERRIDE
-
-@hook TARGET_OPTION_FUNCTION_VERSIONS
-
-@hook TARGET_CAN_INLINE_P
-
-@hook TARGET_UPDATE_IPA_FN_TARGET_INFO
-
-@hook TARGET_NEED_IPA_FN_TARGET_INFO
-
-@hook TARGET_RELAYOUT_FUNCTION
-
-@node Emulated TLS
-@section Emulating TLS
-@cindex Emulated TLS
-
-For targets whose psABI does not provide Thread Local Storage via
-specific relocations and instruction sequences, an emulation layer is
-used. A set of target hooks allows this emulation layer to be
-configured for the requirements of a particular target. For instance
-the psABI may in fact specify TLS support in terms of an emulation
-layer.
-
-The emulation layer works by creating a control object for every TLS
-object. To access the TLS object, a lookup function is provided
-which, when given the address of the control object, will return the
-address of the current thread's instance of the TLS object.
-
-@hook TARGET_EMUTLS_GET_ADDRESS
-
-@hook TARGET_EMUTLS_REGISTER_COMMON
-
-@hook TARGET_EMUTLS_VAR_SECTION
-
-@hook TARGET_EMUTLS_TMPL_SECTION
-
-@hook TARGET_EMUTLS_VAR_PREFIX
-
-@hook TARGET_EMUTLS_TMPL_PREFIX
-
-@hook TARGET_EMUTLS_VAR_FIELDS
-
-@hook TARGET_EMUTLS_VAR_INIT
-
-@hook TARGET_EMUTLS_VAR_ALIGN_FIXED
-
-@hook TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS
-
-@node MIPS Coprocessors
-@section Defining coprocessor specifics for MIPS targets.
-@cindex MIPS coprocessor-definition macros
-
-The MIPS specification allows MIPS implementations to have as many as 4
-coprocessors, each with as many as 32 private registers. GCC supports
-accessing these registers and transferring values between the registers
-and memory using asm-ized variables. For example:
-
-@smallexample
- register unsigned int cp0count asm ("c0r1");
- unsigned int d;
-
- d = cp0count + 3;
-@end smallexample
-
-(``c0r1'' is the default name of register 1 in coprocessor 0; alternate
-names may be added as described below, or the default names may be
-overridden entirely in @code{SUBTARGET_CONDITIONAL_REGISTER_USAGE}.)
-
-Coprocessor registers are assumed to be epilogue-used; sets to them will
-be preserved even if it does not appear that the register is used again
-later in the function.
-
-Another note: according to the MIPS spec, coprocessor 1 (if present) is
-the FPU@. One accesses COP1 registers through standard mips
-floating-point support; they are not included in this mechanism.
-
-@node PCH Target
-@section Parameters for Precompiled Header Validity Checking
-@cindex parameters, precompiled headers
-
-@hook TARGET_GET_PCH_VALIDITY
-
-@hook TARGET_PCH_VALID_P
-
-@hook TARGET_CHECK_PCH_TARGET_FLAGS
-
-@hook TARGET_PREPARE_PCH_SAVE
-
-@node C++ ABI
-@section C++ ABI parameters
-@cindex parameters, c++ abi
-
-@hook TARGET_CXX_GUARD_TYPE
-
-@hook TARGET_CXX_GUARD_MASK_BIT
-
-@hook TARGET_CXX_GET_COOKIE_SIZE
-
-@hook TARGET_CXX_COOKIE_HAS_SIZE
-
-@hook TARGET_CXX_IMPORT_EXPORT_CLASS
-
-@hook TARGET_CXX_CDTOR_RETURNS_THIS
-
-@hook TARGET_CXX_KEY_METHOD_MAY_BE_INLINE
-
-@hook TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY
-
-@hook TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT
-
-@hook TARGET_CXX_LIBRARY_RTTI_COMDAT
-
-@hook TARGET_CXX_USE_AEABI_ATEXIT
-
-@hook TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT
-
-@hook TARGET_CXX_ADJUST_CLASS_AT_DEFINITION
-
-@hook TARGET_CXX_DECL_MANGLING_CONTEXT
-
-@node D Language and ABI
-@section D ABI parameters
-@cindex parameters, d abi
-
-@hook TARGET_D_CPU_VERSIONS
-
-@hook TARGET_D_OS_VERSIONS
-
-@hook TARGET_D_REGISTER_CPU_TARGET_INFO
-
-@hook TARGET_D_REGISTER_OS_TARGET_INFO
-
-@hook TARGET_D_MINFO_SECTION
-
-@hook TARGET_D_MINFO_START_NAME
-
-@hook TARGET_D_MINFO_END_NAME
-
-@hook TARGET_D_HAS_STDCALL_CONVENTION
-
-@hook TARGET_D_TEMPLATES_ALWAYS_COMDAT
-
-@node Named Address Spaces
-@section Adding support for named address spaces
-@cindex named address spaces
-
-The draft technical report of the ISO/IEC JTC1 S22 WG14 N1275
-standards committee, @cite{Programming Languages - C - Extensions to
-support embedded processors}, specifies a syntax for embedded
-processors to specify alternate address spaces. You can configure a
-GCC port to support section 5.1 of the draft report to add support for
-address spaces other than the default address space. These address
-spaces are new keywords that are similar to the @code{volatile} and
-@code{const} type attributes.
-
-Pointers to named address spaces can have a different size than
-pointers to the generic address space.
-
-For example, the SPU port uses the @code{__ea} address space to refer
-to memory in the host processor, rather than memory local to the SPU
-processor. Access to memory in the @code{__ea} address space involves
-issuing DMA operations to move data between the host processor and the
-local processor memory address space. Pointers in the @code{__ea}
-address space are either 32 bits or 64 bits based on the
-@option{-mea32} or @option{-mea64} switches (native SPU pointers are
-always 32 bits).
-
-Internally, address spaces are represented as a small integer in the
-range 0 to 15 with address space 0 being reserved for the generic
-address space.
-
-To register a named address space qualifier keyword with the C front end,
-the target may call the @code{c_register_addr_space} routine. For example,
-the SPU port uses the following to declare @code{__ea} as the keyword for
-named address space #1:
-@smallexample
-#define ADDR_SPACE_EA 1
-c_register_addr_space ("__ea", ADDR_SPACE_EA);
-@end smallexample
-
-@hook TARGET_ADDR_SPACE_POINTER_MODE
-
-@hook TARGET_ADDR_SPACE_ADDRESS_MODE
-
-@hook TARGET_ADDR_SPACE_VALID_POINTER_MODE
-
-@hook TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P
-
-@hook TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS
-
-@hook TARGET_ADDR_SPACE_SUBSET_P
-
-@hook TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID
-
-@hook TARGET_ADDR_SPACE_CONVERT
-
-@hook TARGET_ADDR_SPACE_DEBUG
-
-@hook TARGET_ADDR_SPACE_DIAGNOSE_USAGE
-
-@node Misc
-@section Miscellaneous Parameters
-@cindex parameters, miscellaneous
-
-@c prevent bad page break with this line
-Here are several miscellaneous parameters.
-
-@defmac HAS_LONG_COND_BRANCH
-Define this boolean macro to indicate whether or not your architecture
-has conditional branches that can span all of memory. It is used in
-conjunction with an optimization that partitions hot and cold basic
-blocks into separate sections of the executable. If this macro is
-set to false, gcc will convert any conditional branches that attempt
-to cross between sections into unconditional branches or indirect jumps.
-@end defmac
-
-@defmac HAS_LONG_UNCOND_BRANCH
-Define this boolean macro to indicate whether or not your architecture
-has unconditional branches that can span all of memory. It is used in
-conjunction with an optimization that partitions hot and cold basic
-blocks into separate sections of the executable. If this macro is
-set to false, gcc will convert any unconditional branches that attempt
-to cross between sections into indirect jumps.
-@end defmac
-
-@defmac CASE_VECTOR_MODE
-An alias for a machine mode name. This is the machine mode that
-elements of a jump-table should have.
-@end defmac
-
-@defmac CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
-Optional: return the preferred mode for an @code{addr_diff_vec}
-when the minimum and maximum offset are known. If you define this,
-it enables extra code in branch shortening to deal with @code{addr_diff_vec}.
-To make this work, you also have to define @code{INSN_ALIGN} and
-make the alignment for @code{addr_diff_vec} explicit.
-The @var{body} argument is provided so that the offset_unsigned and scale
-flags can be updated.
-@end defmac
-
-@defmac CASE_VECTOR_PC_RELATIVE
-Define this macro to be a C expression to indicate when jump-tables
-should contain relative addresses. You need not define this macro if
-jump-tables never contain relative addresses, or jump-tables should
-contain relative addresses only when @option{-fPIC} or @option{-fPIC}
-is in effect.
-@end defmac
-
-@hook TARGET_CASE_VALUES_THRESHOLD
-
-@defmac WORD_REGISTER_OPERATIONS
-Define this macro to 1 if operations between registers with integral mode
-smaller than a word are always performed on the entire register. To be
-more explicit, if you start with a pair of @code{word_mode} registers with
-known values and you do a subword, for example @code{QImode}, addition on
-the low part of the registers, then the compiler may consider that the
-result has a known value in @code{word_mode} too if the macro is defined
-to 1. Most RISC machines have this property and most CISC machines do not.
-@end defmac
-
-@hook TARGET_MIN_ARITHMETIC_PRECISION
-
-@defmac LOAD_EXTEND_OP (@var{mem_mode})
-Define this macro to be a C expression indicating when insns that read
-memory in @var{mem_mode}, an integral mode narrower than a word, set the
-bits outside of @var{mem_mode} to be either the sign-extension or the
-zero-extension of the data read. Return @code{SIGN_EXTEND} for values
-of @var{mem_mode} for which the
-insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and
-@code{UNKNOWN} for other modes.
-
-This macro is not called with @var{mem_mode} non-integral or with a width
-greater than or equal to @code{BITS_PER_WORD}, so you may return any
-value in this case. Do not define this macro if it would always return
-@code{UNKNOWN}. On machines where this macro is defined, you will normally
-define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}.
-
-You may return a non-@code{UNKNOWN} value even if for some hard registers
-the sign extension is not performed, if for the @code{REGNO_REG_CLASS}
-of these hard registers @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false
-when the @var{from} mode is @var{mem_mode} and the @var{to} mode is any
-integral mode larger than this but not larger than @code{word_mode}.
-
-You must return @code{UNKNOWN} if for some hard registers that allow this
-mode, @code{TARGET_CAN_CHANGE_MODE_CLASS} says that they cannot change to
-@code{word_mode}, but that they can change to another integral mode that
-is larger then @var{mem_mode} but still smaller than @code{word_mode}.
-@end defmac
-
-@defmac SHORT_IMMEDIATES_SIGN_EXTEND
-Define this macro to 1 if loading short immediate values into registers sign
-extends.
-@end defmac
-
-@hook TARGET_MIN_DIVISIONS_FOR_RECIP_MUL
-
-@defmac MOVE_MAX
-The maximum number of bytes that a single instruction can move quickly
-between memory and registers or between two memory locations.
-@end defmac
-
-@defmac MAX_MOVE_MAX
-The maximum number of bytes that a single instruction can move quickly
-between memory and registers or between two memory locations. If this
-is undefined, the default is @code{MOVE_MAX}. Otherwise, it is the
-constant value that is the largest value that @code{MOVE_MAX} can have
-at run-time.
-@end defmac
-
-@defmac SHIFT_COUNT_TRUNCATED
-A C expression that is nonzero if on this machine the number of bits
-actually used for the count of a shift operation is equal to the number
-of bits needed to represent the size of the object being shifted. When
-this macro is nonzero, the compiler will assume that it is safe to omit
-a sign-extend, zero-extend, and certain bitwise `and' instructions that
-truncates the count of a shift operation. On machines that have
-instructions that act on bit-fields at variable positions, which may
-include `bit test' instructions, a nonzero @code{SHIFT_COUNT_TRUNCATED}
-also enables deletion of truncations of the values that serve as
-arguments to bit-field instructions.
-
-If both types of instructions truncate the count (for shifts) and
-position (for bit-field operations), or if no variable-position bit-field
-instructions exist, you should define this macro.
-
-However, on some machines, such as the 80386 and the 680x0, truncation
-only applies to shift operations and not the (real or pretended)
-bit-field operations. Define @code{SHIFT_COUNT_TRUNCATED} to be zero on
-such machines. Instead, add patterns to the @file{md} file that include
-the implied truncation of the shift instructions.
-
-You need not define this macro if it would always have the value of zero.
-@end defmac
-
-@anchor{TARGET_SHIFT_TRUNCATION_MASK}
-@hook TARGET_SHIFT_TRUNCATION_MASK
-
-@hook TARGET_TRULY_NOOP_TRUNCATION
-
-@hook TARGET_MODE_REP_EXTENDED
-
-@hook TARGET_SETJMP_PRESERVES_NONVOLATILE_REGS_P
-
-@defmac STORE_FLAG_VALUE
-A C expression describing the value returned by a comparison operator
-with an integral mode and stored by a store-flag instruction
-(@samp{cstore@var{mode}4}) when the condition is true. This description must
-apply to @emph{all} the @samp{cstore@var{mode}4} patterns and all the
-comparison operators whose results have a @code{MODE_INT} mode.
-
-A value of 1 or @minus{}1 means that the instruction implementing the
-comparison operator returns exactly 1 or @minus{}1 when the comparison is true
-and 0 when the comparison is false. Otherwise, the value indicates
-which bits of the result are guaranteed to be 1 when the comparison is
-true. This value is interpreted in the mode of the comparison
-operation, which is given by the mode of the first operand in the
-@samp{cstore@var{mode}4} pattern. Either the low bit or the sign bit of
-@code{STORE_FLAG_VALUE} be on. Presently, only those bits are used by
-the compiler.
-
-If @code{STORE_FLAG_VALUE} is neither 1 or @minus{}1, the compiler will
-generate code that depends only on the specified bits. It can also
-replace comparison operators with equivalent operations if they cause
-the required bits to be set, even if the remaining bits are undefined.
-For example, on a machine whose comparison operators return an
-@code{SImode} value and where @code{STORE_FLAG_VALUE} is defined as
-@samp{0x80000000}, saying that just the sign bit is relevant, the
-expression
-
-@smallexample
-(ne:SI (and:SI @var{x} (const_int @var{power-of-2})) (const_int 0))
-@end smallexample
-
-@noindent
-can be converted to
-
-@smallexample
-(ashift:SI @var{x} (const_int @var{n}))
-@end smallexample
-
-@noindent
-where @var{n} is the appropriate shift count to move the bit being
-tested into the sign bit.
-
-There is no way to describe a machine that always sets the low-order bit
-for a true value, but does not guarantee the value of any other bits,
-but we do not know of any machine that has such an instruction. If you
-are trying to port GCC to such a machine, include an instruction to
-perform a logical-and of the result with 1 in the pattern for the
-comparison operators and let us know at @email{gcc@@gcc.gnu.org}.
-
-Often, a machine will have multiple instructions that obtain a value
-from a comparison (or the condition codes). Here are rules to guide the
-choice of value for @code{STORE_FLAG_VALUE}, and hence the instructions
-to be used:
-
-@itemize @bullet
-@item
-Use the shortest sequence that yields a valid definition for
-@code{STORE_FLAG_VALUE}. It is more efficient for the compiler to
-``normalize'' the value (convert it to, e.g., 1 or 0) than for the
-comparison operators to do so because there may be opportunities to
-combine the normalization with other operations.
-
-@item
-For equal-length sequences, use a value of 1 or @minus{}1, with @minus{}1 being
-slightly preferred on machines with expensive jumps and 1 preferred on
-other machines.
-
-@item
-As a second choice, choose a value of @samp{0x80000001} if instructions
-exist that set both the sign and low-order bits but do not define the
-others.
-
-@item
-Otherwise, use a value of @samp{0x80000000}.
-@end itemize
-
-Many machines can produce both the value chosen for
-@code{STORE_FLAG_VALUE} and its negation in the same number of
-instructions. On those machines, you should also define a pattern for
-those cases, e.g., one matching
-
-@smallexample
-(set @var{A} (neg:@var{m} (ne:@var{m} @var{B} @var{C})))
-@end smallexample
-
-Some machines can also perform @code{and} or @code{plus} operations on
-condition code values with less instructions than the corresponding
-@samp{cstore@var{mode}4} insn followed by @code{and} or @code{plus}. On those
-machines, define the appropriate patterns. Use the names @code{incscc}
-and @code{decscc}, respectively, for the patterns which perform
-@code{plus} or @code{minus} operations on condition code values. See
-@file{rs6000.md} for some examples. The GNU Superoptimizer can be used to
-find such instruction sequences on other machines.
-
-If this macro is not defined, the default value, 1, is used. You need
-not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
-instructions, or if the value generated by these instructions is 1.
-@end defmac
-
-@defmac FLOAT_STORE_FLAG_VALUE (@var{mode})
-A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is
-returned when comparison operators with floating-point results are true.
-Define this macro on machines that have comparison operations that return
-floating-point values. If there are no such operations, do not define
-this macro.
-@end defmac
-
-@defmac VECTOR_STORE_FLAG_VALUE (@var{mode})
-A C expression that gives an rtx representing the nonzero true element
-for vector comparisons. The returned rtx should be valid for the inner
-mode of @var{mode} which is guaranteed to be a vector mode. Define
-this macro on machines that have vector comparison operations that
-return a vector result. If there are no such operations, do not define
-this macro. Typically, this macro is defined as @code{const1_rtx} or
-@code{constm1_rtx}. This macro may return @code{NULL_RTX} to prevent
-the compiler optimizing such vector comparison operations for the
-given mode.
-@end defmac
-
-@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
-@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
-A C expression that indicates whether the architecture defines a value
-for @code{clz} or @code{ctz} with a zero operand.
-A result of @code{0} indicates the value is undefined.
-If the value is defined for only the RTL expression, the macro should
-evaluate to @code{1}; if the value applies also to the corresponding optab
-entry (which is normally the case if it expands directly into
-the corresponding RTL), then the macro should evaluate to @code{2}.
-In the cases where the value is defined, @var{value} should be set to
-this value.
-
-If this macro is not defined, the value of @code{clz} or
-@code{ctz} at zero is assumed to be undefined.
-
-This macro must be defined if the target's expansion for @code{ffs}
-relies on a particular value to get correct results. Otherwise it
-is not necessary, though it may be used to optimize some corner cases, and
-to provide a default expansion for the @code{ffs} optab.
-
-Note that regardless of this macro the ``definedness'' of @code{clz}
-and @code{ctz} at zero do @emph{not} extend to the builtin functions
-visible to the user. Thus one may be free to adjust the value at will
-to match the target expansion of these operations without fear of
-breaking the API@.
-@end defmac
-
-@defmac Pmode
-An alias for the machine mode for pointers. On most machines, define
-this to be the integer mode corresponding to the width of a hardware
-pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines.
-On some machines you must define this to be one of the partial integer
-modes, such as @code{PSImode}.
-
-The width of @code{Pmode} must be at least as large as the value of
-@code{POINTER_SIZE}. If it is not equal, you must define the macro
-@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended
-to @code{Pmode}.
-@end defmac
-
-@defmac FUNCTION_MODE
-An alias for the machine mode used for memory references to functions
-being called, in @code{call} RTL expressions. On most CISC machines,
-where an instruction can begin at any byte address, this should be
-@code{QImode}. On most RISC machines, where all instructions have fixed
-size and alignment, this should be a mode with the same size and alignment
-as the machine instruction words - typically @code{SImode} or @code{HImode}.
-@end defmac
-
-@defmac STDC_0_IN_SYSTEM_HEADERS
-In normal operation, the preprocessor expands @code{__STDC__} to the
-constant 1, to signify that GCC conforms to ISO Standard C@. On some
-hosts, like Solaris, the system compiler uses a different convention,
-where @code{__STDC__} is normally 0, but is 1 if the user specifies
-strict conformance to the C Standard.
-
-Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host
-convention when processing system header files, but when processing user
-files @code{__STDC__} will always expand to 1.
-@end defmac
-
-@hook TARGET_C_PREINCLUDE
-
-@hook TARGET_CXX_IMPLICIT_EXTERN_C
-
-@defmac SYSTEM_IMPLICIT_EXTERN_C
-Define this macro if the system header files do not support C++@.
-This macro handles system header files by pretending that system
-header files are enclosed in @samp{extern "C" @{@dots{}@}}.
-@end defmac
-
-@findex #pragma
-@findex pragma
-@defmac REGISTER_TARGET_PRAGMAS ()
-Define this macro if you want to implement any target-specific pragmas.
-If defined, it is a C expression which makes a series of calls to
-@code{c_register_pragma} or @code{c_register_pragma_with_expansion}
-for each pragma. The macro may also do any
-setup required for the pragmas.
-
-The primary reason to define this macro is to provide compatibility with
-other compilers for the same target. In general, we discourage
-definition of target-specific pragmas for GCC@.
-
-If the pragma can be implemented by attributes then you should consider
-defining the target hook @samp{TARGET_INSERT_ATTRIBUTES} as well.
-
-Preprocessor macros that appear on pragma lines are not expanded. All
-@samp{#pragma} directives that do not match any registered pragma are
-silently ignored, unless the user specifies @option{-Wunknown-pragmas}.
-@end defmac
-
-@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-@deftypefunx void c_register_pragma_with_expansion (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-
-Each call to @code{c_register_pragma} or
-@code{c_register_pragma_with_expansion} establishes one pragma. The
-@var{callback} routine will be called when the preprocessor encounters a
-pragma of the form
-
-@smallexample
-#pragma [@var{space}] @var{name} @dots{}
-@end smallexample
-
-@var{space} is the case-sensitive namespace of the pragma, or
-@code{NULL} to put the pragma in the global namespace. The callback
-routine receives @var{pfile} as its first argument, which can be passed
-on to cpplib's functions if necessary. You can lex tokens after the
-@var{name} by calling @code{pragma_lex}. Tokens that are not read by the
-callback will be silently ignored. The end of the line is indicated by
-a token of type @code{CPP_EOF}. Macro expansion occurs on the
-arguments of pragmas registered with
-@code{c_register_pragma_with_expansion} but not on the arguments of
-pragmas registered with @code{c_register_pragma}.
-
-Note that the use of @code{pragma_lex} is specific to the C and C++
-compilers. It will not work in the Java or Fortran compilers, or any
-other language compilers for that matter. Thus if @code{pragma_lex} is going
-to be called from target-specific code, it must only be done so when
-building the C and C++ compilers. This can be done by defining the
-variables @code{c_target_objs} and @code{cxx_target_objs} in the
-target entry in the @file{config.gcc} file. These variables should name
-the target-specific, language-specific object file which contains the
-code that uses @code{pragma_lex}. Note it will also be necessary to add a
-rule to the makefile fragment pointed to by @code{tmake_file} that shows
-how to build this object file.
-@end deftypefun
-
-@defmac HANDLE_PRAGMA_PACK_WITH_EXPANSION
-Define this macro if macros should be expanded in the
-arguments of @samp{#pragma pack}.
-@end defmac
-
-@defmac TARGET_DEFAULT_PACK_STRUCT
-If your target requires a structure packing default other than 0 (meaning
-the machine default), define this macro to the necessary value (in bytes).
-This must be a value that would also be valid to use with
-@samp{#pragma pack()} (that is, a small power of two).
-@end defmac
-
-@defmac DOLLARS_IN_IDENTIFIERS
-Define this macro to control use of the character @samp{$} in
-identifier names for the C family of languages. 0 means @samp{$} is
-not allowed by default; 1 means it is allowed. 1 is the default;
-there is no need to define this macro in that case.
-@end defmac
-
-@defmac INSN_SETS_ARE_DELAYED (@var{insn})
-Define this macro as a C expression that is nonzero if it is safe for the
-delay slot scheduler to place instructions in the delay slot of @var{insn},
-even if they appear to use a resource set or clobbered in @var{insn}.
-@var{insn} is always a @code{jump_insn} or an @code{insn}; GCC knows that
-every @code{call_insn} has this behavior. On machines where some @code{insn}
-or @code{jump_insn} is really a function call and hence has this behavior,
-you should define this macro.
-
-You need not define this macro if it would always return zero.
-@end defmac
-
-@defmac INSN_REFERENCES_ARE_DELAYED (@var{insn})
-Define this macro as a C expression that is nonzero if it is safe for the
-delay slot scheduler to place instructions in the delay slot of @var{insn},
-even if they appear to set or clobber a resource referenced in @var{insn}.
-@var{insn} is always a @code{jump_insn} or an @code{insn}. On machines where
-some @code{insn} or @code{jump_insn} is really a function call and its operands
-are registers whose use is actually in the subroutine it calls, you should
-define this macro. Doing so allows the delay slot scheduler to move
-instructions which copy arguments into the argument registers into the delay
-slot of @var{insn}.
-
-You need not define this macro if it would always return zero.
-@end defmac
-
-@defmac MULTIPLE_SYMBOL_SPACES
-Define this macro as a C expression that is nonzero if, in some cases,
-global symbols from one translation unit may not be bound to undefined
-symbols in another translation unit without user intervention. For
-instance, under Microsoft Windows symbols must be explicitly imported
-from shared libraries (DLLs).
-
-You need not define this macro if it would always evaluate to zero.
-@end defmac
-
-@hook TARGET_MD_ASM_ADJUST
-
-@defmac MATH_LIBRARY
-Define this macro as a C string constant for the linker argument to link
-in the system math library, minus the initial @samp{"-l"}, or
-@samp{""} if the target does not have a
-separate math library.
-
-You need only define this macro if the default of @samp{"m"} is wrong.
-@end defmac
-
-@defmac LIBRARY_PATH_ENV
-Define this macro as a C string constant for the environment variable that
-specifies where the linker should look for libraries.
-
-You need only define this macro if the default of @samp{"LIBRARY_PATH"}
-is wrong.
-@end defmac
-
-@defmac TARGET_POSIX_IO
-Define this macro if the target supports the following POSIX@ file
-functions, access, mkdir and file locking with fcntl / F_SETLKW@.
-Defining @code{TARGET_POSIX_IO} will enable the test coverage code
-to use file locking when exiting a program, which avoids race conditions
-if the program has forked. It will also create directories at run-time
-for cross-profiling.
-@end defmac
-
-@defmac MAX_CONDITIONAL_EXECUTE
-
-A C expression for the maximum number of instructions to execute via
-conditional execution instructions instead of a branch. A value of
-@code{BRANCH_COST}+1 is the default.
-@end defmac
-
-@defmac IFCVT_MODIFY_TESTS (@var{ce_info}, @var{true_expr}, @var{false_expr})
-Used if the target needs to perform machine-dependent modifications on the
-conditionals used for turning basic blocks into conditionally executed code.
-@var{ce_info} points to a data structure, @code{struct ce_if_block}, which
-contains information about the currently processed blocks. @var{true_expr}
-and @var{false_expr} are the tests that are used for converting the
-then-block and the else-block, respectively. Set either @var{true_expr} or
-@var{false_expr} to a null pointer if the tests cannot be converted.
-@end defmac
-
-@defmac IFCVT_MODIFY_MULTIPLE_TESTS (@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr})
-Like @code{IFCVT_MODIFY_TESTS}, but used when converting more complicated
-if-statements into conditions combined by @code{and} and @code{or} operations.
-@var{bb} contains the basic block that contains the test that is currently
-being processed and about to be turned into a condition.
-@end defmac
-
-@defmac IFCVT_MODIFY_INSN (@var{ce_info}, @var{pattern}, @var{insn})
-A C expression to modify the @var{PATTERN} of an @var{INSN} that is to
-be converted to conditional execution format. @var{ce_info} points to
-a data structure, @code{struct ce_if_block}, which contains information
-about the currently processed blocks.
-@end defmac
-
-@defmac IFCVT_MODIFY_FINAL (@var{ce_info})
-A C expression to perform any final machine dependent modifications in
-converting code to conditional execution. The involved basic blocks
-can be found in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@defmac IFCVT_MODIFY_CANCEL (@var{ce_info})
-A C expression to cancel any machine dependent modifications in
-converting code to conditional execution. The involved basic blocks
-can be found in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@defmac IFCVT_MACHDEP_INIT (@var{ce_info})
-A C expression to initialize any machine specific data for if-conversion
-of the if-block in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@hook TARGET_MACHINE_DEPENDENT_REORG
-
-@hook TARGET_INIT_BUILTINS
-
-@hook TARGET_BUILTIN_DECL
-
-@hook TARGET_EXPAND_BUILTIN
-
-@hook TARGET_RESOLVE_OVERLOADED_BUILTIN
-
-@hook TARGET_CHECK_BUILTIN_CALL
-
-@hook TARGET_FOLD_BUILTIN
-
-@hook TARGET_GIMPLE_FOLD_BUILTIN
-
-@hook TARGET_COMPARE_VERSION_PRIORITY
-
-@hook TARGET_GET_FUNCTION_VERSIONS_DISPATCHER
-
-@hook TARGET_GENERATE_VERSION_DISPATCHER_BODY
-
-@hook TARGET_PREDICT_DOLOOP_P
-
-@hook TARGET_HAVE_COUNT_REG_DECR_P
-
-@hook TARGET_DOLOOP_COST_FOR_GENERIC
-
-@hook TARGET_DOLOOP_COST_FOR_ADDRESS
-
-@hook TARGET_CAN_USE_DOLOOP_P
-
-@hook TARGET_INVALID_WITHIN_DOLOOP
-
-@hook TARGET_PREFERRED_DOLOOP_MODE
-
-@hook TARGET_LEGITIMATE_COMBINED_INSN
-
-@hook TARGET_CAN_FOLLOW_JUMP
-
-@hook TARGET_COMMUTATIVE_P
-
-@hook TARGET_ALLOCATE_INITIAL_VALUE
-
-@hook TARGET_UNSPEC_MAY_TRAP_P
-
-@hook TARGET_SET_CURRENT_FUNCTION
-
-@defmac TARGET_OBJECT_SUFFIX
-Define this macro to be a C string representing the suffix for object
-files on your target machine. If you do not define this macro, GCC will
-use @samp{.o} as the suffix for object files.
-@end defmac
-
-@defmac TARGET_EXECUTABLE_SUFFIX
-Define this macro to be a C string representing the suffix to be
-automatically added to executable files on your target machine. If you
-do not define this macro, GCC will use the null string as the suffix for
-executable files.
-@end defmac
-
-@defmac COLLECT_EXPORT_LIST
-If defined, @code{collect2} will scan the individual object files
-specified on its command line and create an export list for the linker.
-Define this macro for systems like AIX, where the linker discards
-object files that are not referenced from @code{main} and uses export
-lists.
-@end defmac
-
-@hook TARGET_CANNOT_MODIFY_JUMPS_P
-
-@hook TARGET_HAVE_CONDITIONAL_EXECUTION
-
-@hook TARGET_GEN_CCMP_FIRST
-
-@hook TARGET_GEN_CCMP_NEXT
-
-@hook TARGET_GEN_MEMSET_SCRATCH_RTX
-
-@hook TARGET_LOOP_UNROLL_ADJUST
-
-@defmac POWI_MAX_MULTS
-If defined, this macro is interpreted as a signed integer C expression
-that specifies the maximum number of floating point multiplications
-that should be emitted when expanding exponentiation by an integer
-constant inline. When this value is defined, exponentiation requiring
-more than this number of multiplications is implemented by calling the
-system library's @code{pow}, @code{powf} or @code{powl} routines.
-The default value places no upper bound on the multiplication count.
-@end defmac
-
-@deftypefn Macro void TARGET_EXTRA_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
-This target hook should register any extra include files for the
-target. The parameter @var{stdinc} indicates if normal include files
-are present. The parameter @var{sysroot} is the system root directory.
-The parameter @var{iprefix} is the prefix for the gcc directory.
-@end deftypefn
-
-@deftypefn Macro void TARGET_EXTRA_PRE_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
-This target hook should register any extra include files for the
-target before any standard headers. The parameter @var{stdinc}
-indicates if normal include files are present. The parameter
-@var{sysroot} is the system root directory. The parameter
-@var{iprefix} is the prefix for the gcc directory.
-@end deftypefn
-
-@deftypefn Macro void TARGET_OPTF (char *@var{path})
-This target hook should register special include paths for the target.
-The parameter @var{path} is the include to register. On Darwin
-systems, this is used for Framework includes, which have semantics
-that are different from @option{-I}.
-@end deftypefn
-
-@defmac bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree @var{fndecl})
-This target macro returns @code{true} if it is safe to use a local alias
-for a virtual function @var{fndecl} when constructing thunks,
-@code{false} otherwise. By default, the macro returns @code{true} for all
-functions, if a target supports aliases (i.e.@: defines
-@code{ASM_OUTPUT_DEF}), @code{false} otherwise,
-@end defmac
-
-@defmac TARGET_FORMAT_TYPES
-If defined, this macro is the name of a global variable containing
-target-specific format checking information for the @option{-Wformat}
-option. The default is to have no target-specific format checks.
-@end defmac
-
-@defmac TARGET_N_FORMAT_TYPES
-If defined, this macro is the number of entries in
-@code{TARGET_FORMAT_TYPES}.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES
-If defined, this macro is the name of a global variable containing
-target-specific format overrides for the @option{-Wformat} option. The
-default is to have no target-specific format overrides. If defined,
-@code{TARGET_FORMAT_TYPES} must be defined, too.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT
-If defined, this macro specifies the number of entries in
-@code{TARGET_OVERRIDES_FORMAT_ATTRIBUTES}.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_INIT
-If defined, this macro specifies the optional initialization
-routine for target specific customizations of the system printf
-and scanf formatter settings.
-@end defmac
-
-@hook TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN
-
-@hook TARGET_INVALID_CONVERSION
-
-@hook TARGET_INVALID_UNARY_OP
-
-@hook TARGET_INVALID_BINARY_OP
-
-@hook TARGET_PROMOTED_TYPE
-
-@hook TARGET_CONVERT_TO_TYPE
-
-@hook TARGET_VERIFY_TYPE_CONTEXT
-
-@defmac OBJC_JBLEN
-This macro determines the size of the objective C jump buffer for the
-NeXT runtime. By default, OBJC_JBLEN is defined to an innocuous value.
-@end defmac
-
-@defmac LIBGCC2_UNWIND_ATTRIBUTE
-Define this macro if any target-specific attributes need to be attached
-to the functions in @file{libgcc} that provide low-level support for
-call stack unwinding. It is used in declarations in @file{unwind-generic.h}
-and the associated definitions of those functions.
-@end defmac
-
-@hook TARGET_UPDATE_STACK_BOUNDARY
-
-@hook TARGET_GET_DRAP_RTX
-
-@hook TARGET_ZERO_CALL_USED_REGS
-
-@hook TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS
-
-@hook TARGET_CONST_ANCHOR
-
-@hook TARGET_ASAN_SHADOW_OFFSET
-
-@hook TARGET_MEMMODEL_CHECK
-
-@hook TARGET_ATOMIC_TEST_AND_SET_TRUEVAL
-
-@hook TARGET_HAS_IFUNC_P
-
-@hook TARGET_IFUNC_REF_LOCAL_OK
-
-@hook TARGET_ATOMIC_ALIGN_FOR_MODE
-
-@hook TARGET_ATOMIC_ASSIGN_EXPAND_FENV
-
-@hook TARGET_RECORD_OFFLOAD_SYMBOL
-
-@hook TARGET_OFFLOAD_OPTIONS
-
-@defmac TARGET_SUPPORTS_WIDE_INT
-
-On older ports, large integers are stored in @code{CONST_DOUBLE} rtl
-objects. Newer ports define @code{TARGET_SUPPORTS_WIDE_INT} to be nonzero
-to indicate that large integers are stored in
-@code{CONST_WIDE_INT} rtl objects. The @code{CONST_WIDE_INT} allows
-very large integer constants to be represented. @code{CONST_DOUBLE}
-is limited to twice the size of the host's @code{HOST_WIDE_INT}
-representation.
-
-Converting a port mostly requires looking for the places where
-@code{CONST_DOUBLE}s are used with @code{VOIDmode} and replacing that
-code with code that accesses @code{CONST_WIDE_INT}s. @samp{"grep -i
-const_double"} at the port level gets you to 95% of the changes that
-need to be made. There are a few places that require a deeper look.
-
-@itemize @bullet
-@item
-There is no equivalent to @code{hval} and @code{lval} for
-@code{CONST_WIDE_INT}s. This would be difficult to express in the md
-language since there are a variable number of elements.
-
-Most ports only check that @code{hval} is either 0 or -1 to see if the
-value is small. As mentioned above, this will no longer be necessary
-since small constants are always @code{CONST_INT}. Of course there
-are still a few exceptions, the alpha's constraint used by the zap
-instruction certainly requires careful examination by C code.
-However, all the current code does is pass the hval and lval to C
-code, so evolving the c code to look at the @code{CONST_WIDE_INT} is
-not really a large change.
-
-@item
-Because there is no standard template that ports use to materialize
-constants, there is likely to be some futzing that is unique to each
-port in this code.
-
-@item
-The rtx costs may have to be adjusted to properly account for larger
-constants that are represented as @code{CONST_WIDE_INT}.
-@end itemize
-
-All and all it does not take long to convert ports that the
-maintainer is familiar with.
-
-@end defmac
-
-@hook TARGET_HAVE_SPECULATION_SAFE_VALUE
-
-@hook TARGET_SPECULATION_SAFE_VALUE
-
-@hook TARGET_RUN_TARGET_SELFTESTS
-
-@hook TARGET_MEMTAG_CAN_TAG_ADDRESSES
-
-@hook TARGET_MEMTAG_TAG_SIZE
-
-@hook TARGET_MEMTAG_GRANULE_SIZE
-
-@hook TARGET_MEMTAG_INSERT_RANDOM_TAG
-
-@hook TARGET_MEMTAG_ADD_TAG
-
-@hook TARGET_MEMTAG_SET_TAG
-
-@hook TARGET_MEMTAG_EXTRACT_TAG
-
-@hook TARGET_MEMTAG_UNTAGGED_POINTER
-
-@hook TARGET_GCOV_TYPE_SIZE
-
-@hook TARGET_HAVE_SHADOW_CALL_STACK
^ permalink raw reply [flat|nested] 2+ messages in thread
* [gcc(refs/users/marxin/heads/sphinx-v6)] Remove tm.texi.in.
@ 2022-03-15 13:44 Martin Liska
0 siblings, 0 replies; 2+ messages in thread
From: Martin Liska @ 2022-03-15 13:44 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:b725eac2c0fd593c57124101a6169af24a550d19
commit b725eac2c0fd593c57124101a6169af24a550d19
Author: Martin Liska <mliska@suse.cz>
Date: Tue Mar 15 14:33:13 2022 +0100
Remove tm.texi.in.
Diff:
---
gcc/doc/tm.texi.in | 8185 ----------------------------------------------------
1 file changed, 8185 deletions(-)
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
deleted file mode 100644
index f869ddd5e5b..00000000000
--- a/gcc/doc/tm.texi.in
+++ /dev/null
@@ -1,8185 +0,0 @@
-@c Copyright (C) 1988-2022 Free Software Foundation, Inc.
-@c This is part of the GCC manual.
-@c For copying conditions, see the file gcc.texi.
-
-@node Target Macros
-@chapter Target Description Macros and Functions
-@cindex machine description macros
-@cindex target description macros
-@cindex macros, target description
-@cindex @file{tm.h} macros
-
-In addition to the file @file{@var{machine}.md}, a machine description
-includes a C header file conventionally given the name
-@file{@var{machine}.h} and a C source file named @file{@var{machine}.c}.
-The header file defines numerous macros that convey the information
-about the target machine that does not fit into the scheme of the
-@file{.md} file. The file @file{tm.h} should be a link to
-@file{@var{machine}.h}. The header file @file{config.h} includes
-@file{tm.h} and most compiler source files include @file{config.h}. The
-source file defines a variable @code{targetm}, which is a structure
-containing pointers to functions and data relating to the target
-machine. @file{@var{machine}.c} should also contain their definitions,
-if they are not defined elsewhere in GCC, and other functions called
-through the macros defined in the @file{.h} file.
-
-@menu
-* Target Structure:: The @code{targetm} variable.
-* Driver:: Controlling how the driver runs the compilation passes.
-* Run-time Target:: Defining @samp{-m} options like @option{-m68000} and @option{-m68020}.
-* Per-Function Data:: Defining data structures for per-function information.
-* Storage Layout:: Defining sizes and alignments of data.
-* Type Layout:: Defining sizes and properties of basic user data types.
-* Registers:: Naming and describing the hardware registers.
-* Register Classes:: Defining the classes of hardware registers.
-* Stack and Calling:: Defining which way the stack grows and by how much.
-* Varargs:: Defining the varargs macros.
-* Trampolines:: Code set up at run time to enter a nested function.
-* Library Calls:: Controlling how library routines are implicitly called.
-* Addressing Modes:: Defining addressing modes valid for memory operands.
-* Anchored Addresses:: Defining how @option{-fsection-anchors} should work.
-* Condition Code:: Defining how insns update the condition code.
-* Costs:: Defining relative costs of different operations.
-* Scheduling:: Adjusting the behavior of the instruction scheduler.
-* Sections:: Dividing storage into text, data, and other sections.
-* PIC:: Macros for position independent code.
-* Assembler Format:: Defining how to write insns and pseudo-ops to output.
-* Debugging Info:: Defining the format of debugging output.
-* Floating Point:: Handling floating point for cross-compilers.
-* Mode Switching:: Insertion of mode-switching instructions.
-* Target Attributes:: Defining target-specific uses of @code{__attribute__}.
-* Emulated TLS:: Emulated TLS support.
-* MIPS Coprocessors:: MIPS coprocessor support and how to customize it.
-* PCH Target:: Validity checking for precompiled headers.
-* C++ ABI:: Controlling C++ ABI changes.
-* D Language and ABI:: Controlling D ABI changes.
-* Named Address Spaces:: Adding support for named address spaces
-* Misc:: Everything else.
-@end menu
-
-@node Target Structure
-@section The Global @code{targetm} Variable
-@cindex target hooks
-@cindex target functions
-
-@deftypevar {struct gcc_target} targetm
-The target @file{.c} file must define the global @code{targetm} variable
-which contains pointers to functions and data relating to the target
-machine. The variable is declared in @file{target.h};
-@file{target-def.h} defines the macro @code{TARGET_INITIALIZER} which is
-used to initialize the variable, and macros for the default initializers
-for elements of the structure. The @file{.c} file should override those
-macros for which the default definition is inappropriate. For example:
-@smallexample
-#include "target.h"
-#include "target-def.h"
-
-/* @r{Initialize the GCC target structure.} */
-
-#undef TARGET_COMP_TYPE_ATTRIBUTES
-#define TARGET_COMP_TYPE_ATTRIBUTES @var{machine}_comp_type_attributes
-
-struct gcc_target targetm = TARGET_INITIALIZER;
-@end smallexample
-@end deftypevar
-
-Where a macro should be defined in the @file{.c} file in this manner to
-form part of the @code{targetm} structure, it is documented below as a
-``Target Hook'' with a prototype. Many macros will change in future
-from being defined in the @file{.h} file to being part of the
-@code{targetm} structure.
-
-Similarly, there is a @code{targetcm} variable for hooks that are
-specific to front ends for C-family languages, documented as ``C
-Target Hook''. This is declared in @file{c-family/c-target.h}, the
-initializer @code{TARGETCM_INITIALIZER} in
-@file{c-family/c-target-def.h}. If targets initialize @code{targetcm}
-themselves, they should set @code{target_has_targetcm=yes} in
-@file{config.gcc}; otherwise a default definition is used.
-
-Similarly, there is a @code{targetm_common} variable for hooks that
-are shared between the compiler driver and the compilers proper,
-documented as ``Common Target Hook''. This is declared in
-@file{common/common-target.h}, the initializer
-@code{TARGETM_COMMON_INITIALIZER} in
-@file{common/common-target-def.h}. If targets initialize
-@code{targetm_common} themselves, they should set
-@code{target_has_targetm_common=yes} in @file{config.gcc}; otherwise a
-default definition is used.
-
-Similarly, there is a @code{targetdm} variable for hooks that are
-specific to the D language front end, documented as ``D Target Hook''.
-This is declared in @file{d/d-target.h}, the initializer
-@code{TARGETDM_INITIALIZER} in @file{d/d-target-def.h}. If targets
-initialize @code{targetdm} themselves, they should set
-@code{target_has_targetdm=yes} in @file{config.gcc}; otherwise a default
-definition is used.
-
-@node Driver
-@section Controlling the Compilation Driver, @file{gcc}
-@cindex driver
-@cindex controlling the compilation driver
-
-@c prevent bad page break with this line
-You can control the compilation driver.
-
-@defmac DRIVER_SELF_SPECS
-A list of specs for the driver itself. It should be a suitable
-initializer for an array of strings, with no surrounding braces.
-
-The driver applies these specs to its own command line between loading
-default @file{specs} files (but not command-line specified ones) and
-choosing the multilib directory or running any subcommands. It
-applies them in the order given, so each spec can depend on the
-options added by earlier ones. It is also possible to remove options
-using @samp{%<@var{option}} in the usual way.
-
-This macro can be useful when a port has several interdependent target
-options. It provides a way of standardizing the command line so
-that the other specs are easier to write.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac OPTION_DEFAULT_SPECS
-A list of specs used to support configure-time default options (i.e.@:
-@option{--with} options) in the driver. It should be a suitable initializer
-for an array of structures, each containing two strings, without the
-outermost pair of surrounding braces.
-
-The first item in the pair is the name of the default. This must match
-the code in @file{config.gcc} for the target. The second item is a spec
-to apply if a default with this name was specified. The string
-@samp{%(VALUE)} in the spec will be replaced by the value of the default
-everywhere it occurs.
-
-The driver will apply these specs to its own command line between loading
-default @file{specs} files and processing @code{DRIVER_SELF_SPECS}, using
-the same mechanism as @code{DRIVER_SELF_SPECS}.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CPP_SPEC
-A C string constant that tells the GCC driver program options to
-pass to CPP@. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the CPP@.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CPLUSPLUS_CPP_SPEC
-This macro is just like @code{CPP_SPEC}, but is used for C++, rather
-than C@. If you do not define this macro, then the value of
-@code{CPP_SPEC} (if any) will be used instead.
-@end defmac
-
-@defmac CC1_SPEC
-A C string constant that tells the GCC driver program options to
-pass to @code{cc1}, @code{cc1plus}, @code{f771}, and the other language
-front ends.
-It can also specify how to translate options you give to GCC into options
-for GCC to pass to front ends.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac CC1PLUS_SPEC
-A C string constant that tells the GCC driver program options to
-pass to @code{cc1plus}. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the @code{cc1plus}.
-
-Do not define this macro if it does not need to do anything.
-Note that everything defined in CC1_SPEC is already passed to
-@code{cc1plus} so there is no need to duplicate the contents of
-CC1_SPEC in CC1PLUS_SPEC@.
-@end defmac
-
-@defmac ASM_SPEC
-A C string constant that tells the GCC driver program options to
-pass to the assembler. It can also specify how to translate options
-you give to GCC into options for GCC to pass to the assembler.
-See the file @file{sun3.h} for an example of this.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac ASM_FINAL_SPEC
-A C string constant that tells the GCC driver program how to
-run any programs which cleanup after the normal assembler.
-Normally, this is not needed. See the file @file{mips.h} for
-an example of this.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac AS_NEEDS_DASH_FOR_PIPED_INPUT
-Define this macro, with no value, if the driver should give the assembler
-an argument consisting of a single dash, @option{-}, to instruct it to
-read from its standard input (which will be a pipe connected to the
-output of the compiler proper). This argument is given after any
-@option{-o} option specifying the name of the output file.
-
-If you do not define this macro, the assembler is assumed to read its
-standard input if given no non-option arguments. If your assembler
-cannot read standard input at all, use a @samp{%@{pipe:%e@}} construct;
-see @file{mips.h} for instance.
-@end defmac
-
-@defmac LINK_SPEC
-A C string constant that tells the GCC driver program options to
-pass to the linker. It can also specify how to translate options you
-give to GCC into options for GCC to pass to the linker.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac LIB_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The difference
-between the two is that @code{LIB_SPEC} is used at the end of the
-command given to the linker.
-
-If this macro is not defined, a default is provided that
-loads the standard C library from the usual place. See @file{gcc.cc}.
-@end defmac
-
-@defmac LIBGCC_SPEC
-Another C string constant that tells the GCC driver program
-how and when to place a reference to @file{libgcc.a} into the
-linker command line. This constant is placed both before and after
-the value of @code{LIB_SPEC}.
-
-If this macro is not defined, the GCC driver provides a default that
-passes the string @option{-lgcc} to the linker.
-@end defmac
-
-@defmac REAL_LIBGCC_SPEC
-By default, if @code{ENABLE_SHARED_LIBGCC} is defined, the
-@code{LIBGCC_SPEC} is not directly used by the driver program but is
-instead modified to refer to different versions of @file{libgcc.a}
-depending on the values of the command line flags @option{-static},
-@option{-shared}, @option{-static-libgcc}, and @option{-shared-libgcc}. On
-targets where these modifications are inappropriate, define
-@code{REAL_LIBGCC_SPEC} instead. @code{REAL_LIBGCC_SPEC} tells the
-driver how to place a reference to @file{libgcc} on the link command
-line, but, unlike @code{LIBGCC_SPEC}, it is used unmodified.
-@end defmac
-
-@defmac USE_LD_AS_NEEDED
-A macro that controls the modifications to @code{LIBGCC_SPEC}
-mentioned in @code{REAL_LIBGCC_SPEC}. If nonzero, a spec will be
-generated that uses @option{--as-needed} or equivalent options and the
-shared @file{libgcc} in place of the
-static exception handler library, when linking without any of
-@code{-static}, @code{-static-libgcc}, or @code{-shared-libgcc}.
-@end defmac
-
-@defmac LINK_EH_SPEC
-If defined, this C string constant is added to @code{LINK_SPEC}.
-When @code{USE_LD_AS_NEEDED} is zero or undefined, it also affects
-the modifications to @code{LIBGCC_SPEC} mentioned in
-@code{REAL_LIBGCC_SPEC}.
-@end defmac
-
-@defmac STARTFILE_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The
-difference between the two is that @code{STARTFILE_SPEC} is used at
-the very beginning of the command given to the linker.
-
-If this macro is not defined, a default is provided that loads the
-standard C startup file from the usual place. See @file{gcc.cc}.
-@end defmac
-
-@defmac ENDFILE_SPEC
-Another C string constant used much like @code{LINK_SPEC}. The
-difference between the two is that @code{ENDFILE_SPEC} is used at
-the very end of the command given to the linker.
-
-Do not define this macro if it does not need to do anything.
-@end defmac
-
-@defmac THREAD_MODEL_SPEC
-GCC @code{-v} will print the thread model GCC was configured to use.
-However, this doesn't work on platforms that are multilibbed on thread
-models, such as AIX 4.3. On such platforms, define
-@code{THREAD_MODEL_SPEC} such that it evaluates to a string without
-blanks that names one of the recognized thread models. @code{%*}, the
-default value of this macro, will expand to the value of
-@code{thread_file} set in @file{config.gcc}.
-@end defmac
-
-@defmac SYSROOT_SUFFIX_SPEC
-Define this macro to add a suffix to the target sysroot when GCC is
-configured with a sysroot. This will cause GCC to search for usr/lib,
-et al, within sysroot+suffix.
-@end defmac
-
-@defmac SYSROOT_HEADERS_SUFFIX_SPEC
-Define this macro to add a headers_suffix to the target sysroot when
-GCC is configured with a sysroot. This will cause GCC to pass the
-updated sysroot+headers_suffix to CPP, causing it to search for
-usr/include, et al, within sysroot+headers_suffix.
-@end defmac
-
-@defmac EXTRA_SPECS
-Define this macro to provide additional specifications to put in the
-@file{specs} file that can be used in various specifications like
-@code{CC1_SPEC}.
-
-The definition should be an initializer for an array of structures,
-containing a string constant, that defines the specification name, and a
-string constant that provides the specification.
-
-Do not define this macro if it does not need to do anything.
-
-@code{EXTRA_SPECS} is useful when an architecture contains several
-related targets, which have various @code{@dots{}_SPECS} which are similar
-to each other, and the maintainer would like one central place to keep
-these definitions.
-
-For example, the PowerPC System V.4 targets use @code{EXTRA_SPECS} to
-define either @code{_CALL_SYSV} when the System V calling sequence is
-used or @code{_CALL_AIX} when the older AIX-based calling sequence is
-used.
-
-The @file{config/rs6000/rs6000.h} target file defines:
-
-@smallexample
-#define EXTRA_SPECS \
- @{ "cpp_sysv_default", CPP_SYSV_DEFAULT @},
-
-#define CPP_SYS_DEFAULT ""
-@end smallexample
-
-The @file{config/rs6000/sysv.h} target file defines:
-@smallexample
-#undef CPP_SPEC
-#define CPP_SPEC \
-"%@{posix: -D_POSIX_SOURCE @} \
-%@{mcall-sysv: -D_CALL_SYSV @} \
-%@{!mcall-sysv: %(cpp_sysv_default) @} \
-%@{msoft-float: -D_SOFT_FLOAT@} %@{mcpu=403: -D_SOFT_FLOAT@}"
-
-#undef CPP_SYSV_DEFAULT
-#define CPP_SYSV_DEFAULT "-D_CALL_SYSV"
-@end smallexample
-
-while the @file{config/rs6000/eabiaix.h} target file defines
-@code{CPP_SYSV_DEFAULT} as:
-
-@smallexample
-#undef CPP_SYSV_DEFAULT
-#define CPP_SYSV_DEFAULT "-D_CALL_AIX"
-@end smallexample
-@end defmac
-
-@defmac LINK_LIBGCC_SPECIAL_1
-Define this macro if the driver program should find the library
-@file{libgcc.a}. If you do not define this macro, the driver program will pass
-the argument @option{-lgcc} to tell the linker to do the search.
-@end defmac
-
-@defmac LINK_GCC_C_SEQUENCE_SPEC
-The sequence in which libgcc and libc are specified to the linker.
-By default this is @code{%G %L %G}.
-@end defmac
-
-@defmac POST_LINK_SPEC
-Define this macro to add additional steps to be executed after linker.
-The default value of this macro is empty string.
-@end defmac
-
-@defmac LINK_COMMAND_SPEC
-A C string constant giving the complete command line need to execute the
-linker. When you do this, you will need to update your port each time a
-change is made to the link command line within @file{gcc.cc}. Therefore,
-define this macro only if you need to completely redefine the command
-line for invoking the linker and there is no other way to accomplish
-the effect you need. Overriding this macro may be avoidable by overriding
-@code{LINK_GCC_C_SEQUENCE_SPEC} instead.
-@end defmac
-
-@hook TARGET_ALWAYS_STRIP_DOTDOT
-
-@defmac MULTILIB_DEFAULTS
-Define this macro as a C expression for the initializer of an array of
-string to tell the driver program which options are defaults for this
-target and thus do not need to be handled specially when using
-@code{MULTILIB_OPTIONS}.
-
-Do not define this macro if @code{MULTILIB_OPTIONS} is not defined in
-the target makefile fragment or if none of the options listed in
-@code{MULTILIB_OPTIONS} are set by default.
-@xref{Target Fragment}.
-@end defmac
-
-@defmac RELATIVE_PREFIX_NOT_LINKDIR
-Define this macro to tell @command{gcc} that it should only translate
-a @option{-B} prefix into a @option{-L} linker option if the prefix
-indicates an absolute file name.
-@end defmac
-
-@defmac MD_EXEC_PREFIX
-If defined, this macro is an additional prefix to try after
-@code{STANDARD_EXEC_PREFIX}. @code{MD_EXEC_PREFIX} is not searched
-when the compiler is built as a cross
-compiler. If you define @code{MD_EXEC_PREFIX}, then be sure to add it
-to the list of directories used to find the assembler in @file{configure.ac}.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{libdir} as the default prefix to
-try when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX_1
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{/lib} as a prefix to try after the default prefix
-when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX_1} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac STANDARD_STARTFILE_PREFIX_2
-Define this macro as a C string constant if you wish to override the
-standard choice of @code{/lib} as yet another prefix to try after the
-default prefix when searching for startup files such as @file{crt0.o}.
-@code{STANDARD_STARTFILE_PREFIX_2} is not searched when the compiler
-is built as a cross compiler.
-@end defmac
-
-@defmac MD_STARTFILE_PREFIX
-If defined, this macro supplies an additional prefix to try after the
-standard prefixes. @code{MD_EXEC_PREFIX} is not searched when the
-compiler is built as a cross compiler.
-@end defmac
-
-@defmac MD_STARTFILE_PREFIX_1
-If defined, this macro supplies yet another prefix to try after the
-standard prefixes. It is not searched when the compiler is built as a
-cross compiler.
-@end defmac
-
-@defmac INIT_ENVIRONMENT
-Define this macro as a C string constant if you wish to set environment
-variables for programs called by the driver, such as the assembler and
-loader. The driver passes the value of this macro to @code{putenv} to
-initialize the necessary environment variables.
-@end defmac
-
-@defmac LOCAL_INCLUDE_DIR
-Define this macro as a C string constant if you wish to override the
-standard choice of @file{/usr/local/include} as the default prefix to
-try when searching for local header files. @code{LOCAL_INCLUDE_DIR}
-comes before @code{NATIVE_SYSTEM_HEADER_DIR} (set in
-@file{config.gcc}, normally @file{/usr/include}) in the search order.
-
-Cross compilers do not search either @file{/usr/local/include} or its
-replacement.
-@end defmac
-
-@defmac NATIVE_SYSTEM_HEADER_COMPONENT
-The ``component'' corresponding to @code{NATIVE_SYSTEM_HEADER_DIR}.
-See @code{INCLUDE_DEFAULTS}, below, for the description of components.
-If you do not define this macro, no component is used.
-@end defmac
-
-@defmac INCLUDE_DEFAULTS
-Define this macro if you wish to override the entire default search path
-for include files. For a native compiler, the default search path
-usually consists of @code{GCC_INCLUDE_DIR}, @code{LOCAL_INCLUDE_DIR},
-@code{GPLUSPLUS_INCLUDE_DIR}, and
-@code{NATIVE_SYSTEM_HEADER_DIR}. In addition, @code{GPLUSPLUS_INCLUDE_DIR}
-and @code{GCC_INCLUDE_DIR} are defined automatically by @file{Makefile},
-and specify private search areas for GCC@. The directory
-@code{GPLUSPLUS_INCLUDE_DIR} is used only for C++ programs.
-
-The definition should be an initializer for an array of structures.
-Each array element should have four elements: the directory name (a
-string constant), the component name (also a string constant), a flag
-for C++-only directories,
-and a flag showing that the includes in the directory don't need to be
-wrapped in @code{extern @samp{C}} when compiling C++. Mark the end of
-the array with a null element.
-
-The component name denotes what GNU package the include file is part of,
-if any, in all uppercase letters. For example, it might be @samp{GCC}
-or @samp{BINUTILS}. If the package is part of a vendor-supplied
-operating system, code the component name as @samp{0}.
-
-For example, here is the definition used for VAX/VMS:
-
-@smallexample
-#define INCLUDE_DEFAULTS \
-@{ \
- @{ "GNU_GXX_INCLUDE:", "G++", 1, 1@}, \
- @{ "GNU_CC_INCLUDE:", "GCC", 0, 0@}, \
- @{ "SYS$SYSROOT:[SYSLIB.]", 0, 0, 0@}, \
- @{ ".", 0, 0, 0@}, \
- @{ 0, 0, 0, 0@} \
-@}
-@end smallexample
-@end defmac
-
-Here is the order of prefixes tried for exec files:
-
-@enumerate
-@item
-Any prefixes specified by the user with @option{-B}.
-
-@item
-The environment variable @code{GCC_EXEC_PREFIX} or, if @code{GCC_EXEC_PREFIX}
-is not set and the compiler has not been installed in the configure-time
-@var{prefix}, the location in which the compiler has actually been installed.
-
-@item
-The directories specified by the environment variable @code{COMPILER_PATH}.
-
-@item
-The macro @code{STANDARD_EXEC_PREFIX}, if the compiler has been installed
-in the configured-time @var{prefix}.
-
-@item
-The location @file{/usr/libexec/gcc/}, but only if this is a native compiler.
-
-@item
-The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
-
-@item
-The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
-compiler.
-@end enumerate
-
-Here is the order of prefixes tried for startfiles:
-
-@enumerate
-@item
-Any prefixes specified by the user with @option{-B}.
-
-@item
-The environment variable @code{GCC_EXEC_PREFIX} or its automatically determined
-value based on the installed toolchain location.
-
-@item
-The directories specified by the environment variable @code{LIBRARY_PATH}
-(or port-specific name; native only, cross compilers do not use this).
-
-@item
-The macro @code{STANDARD_EXEC_PREFIX}, but only if the toolchain is installed
-in the configured @var{prefix} or this is a native compiler.
-
-@item
-The location @file{/usr/lib/gcc/}, but only if this is a native compiler.
-
-@item
-The macro @code{MD_EXEC_PREFIX}, if defined, but only if this is a native
-compiler.
-
-@item
-The macro @code{MD_STARTFILE_PREFIX}, if defined, but only if this is a
-native compiler, or we have a target system root.
-
-@item
-The macro @code{MD_STARTFILE_PREFIX_1}, if defined, but only if this is a
-native compiler, or we have a target system root.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX}, with any sysroot modifications.
-If this path is relative it will be prefixed by @code{GCC_EXEC_PREFIX} and
-the machine suffix or @code{STANDARD_EXEC_PREFIX} and the machine suffix.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX_1}, but only if this is a native
-compiler, or we have a target system root. The default for this macro is
-@file{/lib/}.
-
-@item
-The macro @code{STANDARD_STARTFILE_PREFIX_2}, but only if this is a native
-compiler, or we have a target system root. The default for this macro is
-@file{/usr/lib/}.
-@end enumerate
-
-@node Run-time Target
-@section Run-time Target Specification
-@cindex run-time target specification
-@cindex predefined macros
-@cindex target specifications
-
-@c prevent bad page break with this line
-Here are run-time target specifications.
-
-@defmac TARGET_CPU_CPP_BUILTINS ()
-This function-like macro expands to a block of code that defines
-built-in preprocessor macros and assertions for the target CPU, using
-the functions @code{builtin_define}, @code{builtin_define_std} and
-@code{builtin_assert}. When the front end
-calls this macro it provides a trailing semicolon, and since it has
-finished command line option processing your code can use those
-results freely.
-
-@code{builtin_assert} takes a string in the form you pass to the
-command-line option @option{-A}, such as @code{cpu=mips}, and creates
-the assertion. @code{builtin_define} takes a string in the form
-accepted by option @option{-D} and unconditionally defines the macro.
-
-@code{builtin_define_std} takes a string representing the name of an
-object-like macro. If it doesn't lie in the user's namespace,
-@code{builtin_define_std} defines it unconditionally. Otherwise, it
-defines a version with two leading underscores, and another version
-with two leading and trailing underscores, and defines the original
-only if an ISO standard was not requested on the command line. For
-example, passing @code{unix} defines @code{__unix}, @code{__unix__}
-and possibly @code{unix}; passing @code{_mips} defines @code{__mips},
-@code{__mips__} and possibly @code{_mips}, and passing @code{_ABI64}
-defines only @code{_ABI64}.
-
-You can also test for the C dialect being compiled. The variable
-@code{c_language} is set to one of @code{clk_c}, @code{clk_cplusplus}
-or @code{clk_objective_c}. Note that if we are preprocessing
-assembler, this variable will be @code{clk_c} but the function-like
-macro @code{preprocessing_asm_p()} will return true, so you might want
-to check for that first. If you need to check for strict ANSI, the
-variable @code{flag_iso} can be used. The function-like macro
-@code{preprocessing_trad_p()} can be used to check for traditional
-preprocessing.
-@end defmac
-
-@defmac TARGET_OS_CPP_BUILTINS ()
-Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
-and is used for the target operating system instead.
-@end defmac
-
-@defmac TARGET_OBJFMT_CPP_BUILTINS ()
-Similarly to @code{TARGET_CPU_CPP_BUILTINS} but this macro is optional
-and is used for the target object format. @file{elfos.h} uses this
-macro to define @code{__ELF__}, so you probably do not need to define
-it yourself.
-@end defmac
-
-@deftypevar {extern int} target_flags
-This variable is declared in @file{options.h}, which is included before
-any target-specific headers.
-@end deftypevar
-
-@hook TARGET_DEFAULT_TARGET_FLAGS
-This variable specifies the initial value of @code{target_flags}.
-Its default setting is 0.
-@end deftypevr
-
-@cindex optional hardware or system features
-@cindex features, optional, in system conventions
-
-@hook TARGET_HANDLE_OPTION
-This hook is called whenever the user specifies one of the
-target-specific options described by the @file{.opt} definition files
-(@pxref{Options}). It has the opportunity to do some option-specific
-processing and should return true if the option is valid. The default
-definition does nothing but return true.
-
-@var{decoded} specifies the option and its arguments. @var{opts} and
-@var{opts_set} are the @code{gcc_options} structures to be used for
-storing option state, and @var{loc} is the location at which the
-option was passed (@code{UNKNOWN_LOCATION} except for options passed
-via attributes).
-@end deftypefn
-
-@hook TARGET_HANDLE_C_OPTION
-This target hook is called whenever the user specifies one of the
-target-specific C language family options described by the @file{.opt}
-definition files(@pxref{Options}). It has the opportunity to do some
-option-specific processing and should return true if the option is
-valid. The arguments are like for @code{TARGET_HANDLE_OPTION}. The
-default definition does nothing but return false.
-
-In general, you should use @code{TARGET_HANDLE_OPTION} to handle
-options. However, if processing an option requires routines that are
-only available in the C (and related language) front ends, then you
-should use @code{TARGET_HANDLE_C_OPTION} instead.
-@end deftypefn
-
-@hook TARGET_OBJC_CONSTRUCT_STRING_OBJECT
-
-@hook TARGET_OBJC_DECLARE_UNRESOLVED_CLASS_REFERENCE
-
-@hook TARGET_OBJC_DECLARE_CLASS_DEFINITION
-
-@hook TARGET_STRING_OBJECT_REF_TYPE_P
-
-@hook TARGET_CHECK_STRING_OBJECT_FORMAT_ARG
-
-@hook TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE
-
-@defmac C_COMMON_OVERRIDE_OPTIONS
-This is similar to the @code{TARGET_OPTION_OVERRIDE} hook
-but is only used in the C
-language frontends (C, Objective-C, C++, Objective-C++) and so can be
-used to alter option flag variables which only exist in those
-frontends.
-@end defmac
-
-@hook TARGET_OPTION_OPTIMIZATION_TABLE
-Some machines may desire to change what optimizations are performed for
-various optimization levels. This variable, if defined, describes
-options to enable at particular sets of optimization levels. These
-options are processed once
-just after the optimization level is determined and before the remainder
-of the command options have been parsed, so may be overridden by other
-options passed explicitly.
-
-This processing is run once at program startup and when the optimization
-options are changed via @code{#pragma GCC optimize} or by using the
-@code{optimize} attribute.
-@end deftypevr
-
-@hook TARGET_OPTION_INIT_STRUCT
-
-@defmac SWITCHABLE_TARGET
-Some targets need to switch between substantially different subtargets
-during compilation. For example, the MIPS target has one subtarget for
-the traditional MIPS architecture and another for MIPS16. Source code
-can switch between these two subarchitectures using the @code{mips16}
-and @code{nomips16} attributes.
-
-Such subtargets can differ in things like the set of available
-registers, the set of available instructions, the costs of various
-operations, and so on. GCC caches a lot of this type of information
-in global variables, and recomputing them for each subtarget takes a
-significant amount of time. The compiler therefore provides a facility
-for maintaining several versions of the global variables and quickly
-switching between them; see @file{target-globals.h} for details.
-
-Define this macro to 1 if your target needs this facility. The default
-is 0.
-@end defmac
-
-@hook TARGET_FLOAT_EXCEPTIONS_ROUNDING_SUPPORTED_P
-
-@node Per-Function Data
-@section Defining data structures for per-function information.
-@cindex per-function data
-@cindex data structures
-
-If the target needs to store information on a per-function basis, GCC
-provides a macro and a couple of variables to allow this. Note, just
-using statics to store the information is a bad idea, since GCC supports
-nested functions, so you can be halfway through encoding one function
-when another one comes along.
-
-GCC defines a data structure called @code{struct function} which
-contains all of the data specific to an individual function. This
-structure contains a field called @code{machine} whose type is
-@code{struct machine_function *}, which can be used by targets to point
-to their own specific data.
-
-If a target needs per-function specific data it should define the type
-@code{struct machine_function} and also the macro @code{INIT_EXPANDERS}.
-This macro should be used to initialize the function pointer
-@code{init_machine_status}. This pointer is explained below.
-
-One typical use of per-function, target specific data is to create an
-RTX to hold the register containing the function's return address. This
-RTX can then be used to implement the @code{__builtin_return_address}
-function, for level 0.
-
-Note---earlier implementations of GCC used a single data area to hold
-all of the per-function information. Thus when processing of a nested
-function began the old per-function data had to be pushed onto a
-stack, and when the processing was finished, it had to be popped off the
-stack. GCC used to provide function pointers called
-@code{save_machine_status} and @code{restore_machine_status} to handle
-the saving and restoring of the target specific information. Since the
-single data area approach is no longer used, these pointers are no
-longer supported.
-
-@defmac INIT_EXPANDERS
-Macro called to initialize any target specific information. This macro
-is called once per function, before generation of any RTL has begun.
-The intention of this macro is to allow the initialization of the
-function pointer @code{init_machine_status}.
-@end defmac
-
-@deftypevar {void (*)(struct function *)} init_machine_status
-If this function pointer is non-@code{NULL} it will be called once per
-function, before function compilation starts, in order to allow the
-target to perform any target specific initialization of the
-@code{struct function} structure. It is intended that this would be
-used to initialize the @code{machine} of that structure.
-
-@code{struct machine_function} structures are expected to be freed by GC@.
-Generally, any memory that they reference must be allocated by using
-GC allocation, including the structure itself.
-@end deftypevar
-
-@node Storage Layout
-@section Storage Layout
-@cindex storage layout
-
-Note that the definitions of the macros in this table which are sizes or
-alignments measured in bits do not need to be constant. They can be C
-expressions that refer to static variables, such as the @code{target_flags}.
-@xref{Run-time Target}.
-
-@defmac BITS_BIG_ENDIAN
-Define this macro to have the value 1 if the most significant bit in a
-byte has the lowest number; otherwise define it to have the value zero.
-This means that bit-field instructions count from the most significant
-bit. If the machine has no bit-field instructions, then this must still
-be defined, but it doesn't matter which value it is defined to. This
-macro need not be a constant.
-
-This macro does not affect the way structure fields are packed into
-bytes or words; that is controlled by @code{BYTES_BIG_ENDIAN}.
-@end defmac
-
-@defmac BYTES_BIG_ENDIAN
-Define this macro to have the value 1 if the most significant byte in a
-word has the lowest number. This macro need not be a constant.
-@end defmac
-
-@defmac WORDS_BIG_ENDIAN
-Define this macro to have the value 1 if, in a multiword object, the
-most significant word has the lowest number. This applies to both
-memory locations and registers; see @code{REG_WORDS_BIG_ENDIAN} if the
-order of words in memory is not the same as the order in registers. This
-macro need not be a constant.
-@end defmac
-
-@defmac REG_WORDS_BIG_ENDIAN
-On some machines, the order of words in a multiword object differs between
-registers in memory. In such a situation, define this macro to describe
-the order of words in a register. The macro @code{WORDS_BIG_ENDIAN} controls
-the order of words in memory.
-@end defmac
-
-@defmac FLOAT_WORDS_BIG_ENDIAN
-Define this macro to have the value 1 if @code{DFmode}, @code{XFmode} or
-@code{TFmode} floating point numbers are stored in memory with the word
-containing the sign bit at the lowest address; otherwise define it to
-have the value 0. This macro need not be a constant.
-
-You need not define this macro if the ordering is the same as for
-multi-word integers.
-@end defmac
-
-@defmac BITS_PER_WORD
-Number of bits in a word. If you do not define this macro, the default
-is @code{BITS_PER_UNIT * UNITS_PER_WORD}.
-@end defmac
-
-@defmac MAX_BITS_PER_WORD
-Maximum number of bits in a word. If this is undefined, the default is
-@code{BITS_PER_WORD}. Otherwise, it is the constant value that is the
-largest value that @code{BITS_PER_WORD} can have at run-time.
-@end defmac
-
-@defmac UNITS_PER_WORD
-Number of storage units in a word; normally the size of a general-purpose
-register, a power of two from 1 or 8.
-@end defmac
-
-@defmac MIN_UNITS_PER_WORD
-Minimum number of units in a word. If this is undefined, the default is
-@code{UNITS_PER_WORD}. Otherwise, it is the constant value that is the
-smallest value that @code{UNITS_PER_WORD} can have at run-time.
-@end defmac
-
-@defmac POINTER_SIZE
-Width of a pointer, in bits. You must specify a value no wider than the
-width of @code{Pmode}. If it is not equal to the width of @code{Pmode},
-you must define @code{POINTERS_EXTEND_UNSIGNED}. If you do not specify
-a value the default is @code{BITS_PER_WORD}.
-@end defmac
-
-@defmac POINTERS_EXTEND_UNSIGNED
-A C expression that determines how pointers should be extended from
-@code{ptr_mode} to either @code{Pmode} or @code{word_mode}. It is
-greater than zero if pointers should be zero-extended, zero if they
-should be sign-extended, and negative if some other sort of conversion
-is needed. In the last case, the extension is done by the target's
-@code{ptr_extend} instruction.
-
-You need not define this macro if the @code{ptr_mode}, @code{Pmode}
-and @code{word_mode} are all the same width.
-@end defmac
-
-@defmac PROMOTE_MODE (@var{m}, @var{unsignedp}, @var{type})
-A macro to update @var{m} and @var{unsignedp} when an object whose type
-is @var{type} and which has the specified mode and signedness is to be
-stored in a register. This macro is only called when @var{type} is a
-scalar type.
-
-On most RISC machines, which only have operations that operate on a full
-register, define this macro to set @var{m} to @code{word_mode} if
-@var{m} is an integer mode narrower than @code{BITS_PER_WORD}. In most
-cases, only integer modes should be widened because wider-precision
-floating-point operations are usually more expensive than their narrower
-counterparts.
-
-For most machines, the macro definition does not change @var{unsignedp}.
-However, some machines, have instructions that preferentially handle
-either signed or unsigned quantities of certain modes. For example, on
-the DEC Alpha, 32-bit loads from memory and 32-bit add instructions
-sign-extend the result to 64 bits. On such machines, set
-@var{unsignedp} according to which kind of extension is more efficient.
-
-Do not define this macro if it would never modify @var{m}.
-@end defmac
-
-@hook TARGET_C_EXCESS_PRECISION
-Return a value, with the same meaning as the C99 macro
-@code{FLT_EVAL_METHOD} that describes which excess precision should be
-applied.
-
-@hook TARGET_PROMOTE_FUNCTION_MODE
-
-@defmac PARM_BOUNDARY
-Normal alignment required for function parameters on the stack, in
-bits. All stack parameters receive at least this much alignment
-regardless of data type. On most machines, this is the same as the
-size of an integer.
-@end defmac
-
-@defmac STACK_BOUNDARY
-Define this macro to the minimum alignment enforced by hardware for the
-stack pointer on this machine. The definition is a C expression for the
-desired alignment (measured in bits). This value is used as a default
-if @code{PREFERRED_STACK_BOUNDARY} is not defined. On most machines,
-this should be the same as @code{PARM_BOUNDARY}.
-@end defmac
-
-@defmac PREFERRED_STACK_BOUNDARY
-Define this macro if you wish to preserve a certain alignment for the
-stack pointer, greater than what the hardware enforces. The definition
-is a C expression for the desired alignment (measured in bits). This
-macro must evaluate to a value equal to or larger than
-@code{STACK_BOUNDARY}.
-@end defmac
-
-@defmac INCOMING_STACK_BOUNDARY
-Define this macro if the incoming stack boundary may be different
-from @code{PREFERRED_STACK_BOUNDARY}. This macro must evaluate
-to a value equal to or larger than @code{STACK_BOUNDARY}.
-@end defmac
-
-@defmac FUNCTION_BOUNDARY
-Alignment required for a function entry point, in bits.
-@end defmac
-
-@defmac BIGGEST_ALIGNMENT
-Biggest alignment that any data type can require on this machine, in
-bits. Note that this is not the biggest alignment that is supported,
-just the biggest alignment that, when violated, may cause a fault.
-@end defmac
-
-@hook TARGET_ABSOLUTE_BIGGEST_ALIGNMENT
-
-@defmac MALLOC_ABI_ALIGNMENT
-Alignment, in bits, a C conformant malloc implementation has to
-provide. If not defined, the default value is @code{BITS_PER_WORD}.
-@end defmac
-
-@defmac ATTRIBUTE_ALIGNED_VALUE
-Alignment used by the @code{__attribute__ ((aligned))} construct. If
-not defined, the default value is @code{BIGGEST_ALIGNMENT}.
-@end defmac
-
-@defmac MINIMUM_ATOMIC_ALIGNMENT
-If defined, the smallest alignment, in bits, that can be given to an
-object that can be referenced in one operation, without disturbing any
-nearby object. Normally, this is @code{BITS_PER_UNIT}, but may be larger
-on machines that don't have byte or half-word store operations.
-@end defmac
-
-@defmac BIGGEST_FIELD_ALIGNMENT
-Biggest alignment that any structure or union field can require on this
-machine, in bits. If defined, this overrides @code{BIGGEST_ALIGNMENT} for
-structure and union fields only, unless the field alignment has been set
-by the @code{__attribute__ ((aligned (@var{n})))} construct.
-@end defmac
-
-@defmac ADJUST_FIELD_ALIGN (@var{field}, @var{type}, @var{computed})
-An expression for the alignment of a structure field @var{field} of
-type @var{type} if the alignment computed in the usual way (including
-applying of @code{BIGGEST_ALIGNMENT} and @code{BIGGEST_FIELD_ALIGNMENT} to the
-alignment) is @var{computed}. It overrides alignment only if the
-field alignment has not been set by the
-@code{__attribute__ ((aligned (@var{n})))} construct. Note that @var{field}
-may be @code{NULL_TREE} in case we just query for the minimum alignment
-of a field of type @var{type} in structure context.
-@end defmac
-
-@defmac MAX_STACK_ALIGNMENT
-Biggest stack alignment guaranteed by the backend. Use this macro
-to specify the maximum alignment of a variable on stack.
-
-If not defined, the default value is @code{STACK_BOUNDARY}.
-
-@c FIXME: The default should be @code{PREFERRED_STACK_BOUNDARY}.
-@c But the fix for PR 32893 indicates that we can only guarantee
-@c maximum stack alignment on stack up to @code{STACK_BOUNDARY}, not
-@c @code{PREFERRED_STACK_BOUNDARY}, if stack alignment isn't supported.
-@end defmac
-
-@defmac MAX_OFILE_ALIGNMENT
-Biggest alignment supported by the object file format of this machine.
-Use this macro to limit the alignment which can be specified using the
-@code{__attribute__ ((aligned (@var{n})))} construct for functions and
-objects with static storage duration. The alignment of automatic
-objects may exceed the object file format maximum up to the maximum
-supported by GCC. If not defined, the default value is
-@code{BIGGEST_ALIGNMENT}.
-
-On systems that use ELF, the default (in @file{config/elfos.h}) is
-the largest supported 32-bit ELF section alignment representable on
-a 32-bit host e.g.@: @samp{(((uint64_t) 1 << 28) * 8)}.
-On 32-bit ELF the largest supported section alignment in bits is
-@samp{(0x80000000 * 8)}, but this is not representable on 32-bit hosts.
-@end defmac
-
-@hook TARGET_LOWER_LOCAL_DECL_ALIGNMENT
-
-@hook TARGET_STATIC_RTX_ALIGNMENT
-
-@defmac DATA_ALIGNMENT (@var{type}, @var{basic-align})
-If defined, a C expression to compute the alignment for a variable in
-the static store. @var{type} is the data type, and @var{basic-align} is
-the alignment that the object would ordinarily have. The value of this
-macro is used instead of that alignment to align the object.
-
-If this macro is not defined, then @var{basic-align} is used.
-
-@findex strcpy
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines. Another is to cause character
-arrays to be word-aligned so that @code{strcpy} calls that copy
-constants to character arrays can be done inline.
-@end defmac
-
-@defmac DATA_ABI_ALIGNMENT (@var{type}, @var{basic-align})
-Similar to @code{DATA_ALIGNMENT}, but for the cases where the ABI mandates
-some alignment increase, instead of optimization only purposes. E.g.@
-AMD x86-64 psABI says that variables with array type larger than 15 bytes
-must be aligned to 16 byte boundaries.
-
-If this macro is not defined, then @var{basic-align} is used.
-@end defmac
-
-@hook TARGET_CONSTANT_ALIGNMENT
-
-@defmac LOCAL_ALIGNMENT (@var{type}, @var{basic-align})
-If defined, a C expression to compute the alignment for a variable in
-the local store. @var{type} is the data type, and @var{basic-align} is
-the alignment that the object would ordinarily have. The value of this
-macro is used instead of that alignment to align the object.
-
-If this macro is not defined, then @var{basic-align} is used.
-
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@hook TARGET_VECTOR_ALIGNMENT
-
-@defmac STACK_SLOT_ALIGNMENT (@var{type}, @var{mode}, @var{basic-align})
-If defined, a C expression to compute the alignment for stack slot.
-@var{type} is the data type, @var{mode} is the widest mode available,
-and @var{basic-align} is the alignment that the slot would ordinarily
-have. The value of this macro is used instead of that alignment to
-align the slot.
-
-If this macro is not defined, then @var{basic-align} is used when
-@var{type} is @code{NULL}. Otherwise, @code{LOCAL_ALIGNMENT} will
-be used.
-
-This macro is to set alignment of stack slot to the maximum alignment
-of all possible modes which the slot may have.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@defmac LOCAL_DECL_ALIGNMENT (@var{decl})
-If defined, a C expression to compute the alignment for a local
-variable @var{decl}.
-
-If this macro is not defined, then
-@code{LOCAL_ALIGNMENT (TREE_TYPE (@var{decl}), DECL_ALIGN (@var{decl}))}
-is used.
-
-One use of this macro is to increase alignment of medium-size data to
-make it all fit in fewer cache lines.
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@defmac MINIMUM_ALIGNMENT (@var{exp}, @var{mode}, @var{align})
-If defined, a C expression to compute the minimum required alignment
-for dynamic stack realignment purposes for @var{exp} (a type or decl),
-@var{mode}, assuming normal alignment @var{align}.
-
-If this macro is not defined, then @var{align} will be used.
-@end defmac
-
-@defmac EMPTY_FIELD_BOUNDARY
-Alignment in bits to be given to a structure bit-field that follows an
-empty field such as @code{int : 0;}.
-
-If @code{PCC_BITFIELD_TYPE_MATTERS} is true, it overrides this macro.
-@end defmac
-
-@defmac STRUCTURE_SIZE_BOUNDARY
-Number of bits which any structure or union's size must be a multiple of.
-Each structure or union's size is rounded up to a multiple of this.
-
-If you do not define this macro, the default is the same as
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac STRICT_ALIGNMENT
-Define this macro to be the value 1 if instructions will fail to work
-if given data not on the nominal alignment. If instructions will merely
-go slower in that case, define this macro as 0.
-@end defmac
-
-@defmac PCC_BITFIELD_TYPE_MATTERS
-Define this if you wish to imitate the way many other C compilers handle
-alignment of bit-fields and the structures that contain them.
-
-The behavior is that the type written for a named bit-field (@code{int},
-@code{short}, or other integer type) imposes an alignment for the entire
-structure, as if the structure really did contain an ordinary field of
-that type. In addition, the bit-field is placed within the structure so
-that it would fit within such a field, not crossing a boundary for it.
-
-Thus, on most machines, a named bit-field whose type is written as
-@code{int} would not cross a four-byte boundary, and would force
-four-byte alignment for the whole structure. (The alignment used may
-not be four bytes; it is controlled by the other alignment parameters.)
-
-An unnamed bit-field will not affect the alignment of the containing
-structure.
-
-If the macro is defined, its definition should be a C expression;
-a nonzero value for the expression enables this behavior.
-
-Note that if this macro is not defined, or its value is zero, some
-bit-fields may cross more than one alignment boundary. The compiler can
-support such references if there are @samp{insv}, @samp{extv}, and
-@samp{extzv} insns that can directly reference memory.
-
-The other known way of making bit-fields work is to define
-@code{STRUCTURE_SIZE_BOUNDARY} as large as @code{BIGGEST_ALIGNMENT}.
-Then every structure can be accessed with fullwords.
-
-Unless the machine has bit-field instructions or you define
-@code{STRUCTURE_SIZE_BOUNDARY} that way, you must define
-@code{PCC_BITFIELD_TYPE_MATTERS} to have a nonzero value.
-
-If your aim is to make GCC use the same conventions for laying out
-bit-fields as are used by another compiler, here is how to investigate
-what the other compiler does. Compile and run this program:
-
-@smallexample
-struct foo1
-@{
- char x;
- char :0;
- char y;
-@};
-
-struct foo2
-@{
- char x;
- int :0;
- char y;
-@};
-
-main ()
-@{
- printf ("Size of foo1 is %d\n",
- sizeof (struct foo1));
- printf ("Size of foo2 is %d\n",
- sizeof (struct foo2));
- exit (0);
-@}
-@end smallexample
-
-If this prints 2 and 5, then the compiler's behavior is what you would
-get from @code{PCC_BITFIELD_TYPE_MATTERS}.
-@end defmac
-
-@defmac BITFIELD_NBYTES_LIMITED
-Like @code{PCC_BITFIELD_TYPE_MATTERS} except that its effect is limited
-to aligning a bit-field within the structure.
-@end defmac
-
-@hook TARGET_ALIGN_ANON_BITFIELD
-
-@hook TARGET_NARROW_VOLATILE_BITFIELD
-
-@hook TARGET_MEMBER_TYPE_FORCES_BLK
-
-@defmac ROUND_TYPE_ALIGN (@var{type}, @var{computed}, @var{specified})
-Define this macro as an expression for the alignment of a type (given
-by @var{type} as a tree node) if the alignment computed in the usual
-way is @var{computed} and the alignment explicitly specified was
-@var{specified}.
-
-The default is to use @var{specified} if it is larger; otherwise, use
-the smaller of @var{computed} and @code{BIGGEST_ALIGNMENT}
-@end defmac
-
-@defmac MAX_FIXED_MODE_SIZE
-An integer expression for the size in bits of the largest integer
-machine mode that should actually be used. All integer machine modes of
-this size or smaller can be used for structures and unions with the
-appropriate sizes. If this macro is undefined, @code{GET_MODE_BITSIZE
-(DImode)} is assumed.
-@end defmac
-
-@defmac STACK_SAVEAREA_MODE (@var{save_level})
-If defined, an expression of type @code{machine_mode} that
-specifies the mode of the save area operand of a
-@code{save_stack_@var{level}} named pattern (@pxref{Standard Names}).
-@var{save_level} is one of @code{SAVE_BLOCK}, @code{SAVE_FUNCTION}, or
-@code{SAVE_NONLOCAL} and selects which of the three named patterns is
-having its mode specified.
-
-You need not define this macro if it always returns @code{Pmode}. You
-would most commonly define this macro if the
-@code{save_stack_@var{level}} patterns need to support both a 32- and a
-64-bit mode.
-@end defmac
-
-@defmac STACK_SIZE_MODE
-If defined, an expression of type @code{machine_mode} that
-specifies the mode of the size increment operand of an
-@code{allocate_stack} named pattern (@pxref{Standard Names}).
-
-You need not define this macro if it always returns @code{word_mode}.
-You would most commonly define this macro if the @code{allocate_stack}
-pattern needs to support both a 32- and a 64-bit mode.
-@end defmac
-
-@hook TARGET_LIBGCC_CMP_RETURN_MODE
-
-@hook TARGET_LIBGCC_SHIFT_COUNT_MODE
-
-@hook TARGET_UNWIND_WORD_MODE
-
-@hook TARGET_MS_BITFIELD_LAYOUT_P
-
-@hook TARGET_DECIMAL_FLOAT_SUPPORTED_P
-
-@hook TARGET_FIXED_POINT_SUPPORTED_P
-
-@hook TARGET_EXPAND_TO_RTL_HOOK
-
-@hook TARGET_INSTANTIATE_DECLS
-
-@hook TARGET_MANGLE_TYPE
-
-@node Type Layout
-@section Layout of Source Language Data Types
-
-These macros define the sizes and other characteristics of the standard
-basic data types used in programs being compiled. Unlike the macros in
-the previous section, these apply to specific features of C and related
-languages, rather than to fundamental aspects of storage layout.
-
-@defmac INT_TYPE_SIZE
-A C expression for the size in bits of the type @code{int} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac SHORT_TYPE_SIZE
-A C expression for the size in bits of the type @code{short} on the
-target machine. If you don't define this, the default is half a word.
-(If this would be less than one storage unit, it is rounded up to one
-unit.)
-@end defmac
-
-@defmac LONG_TYPE_SIZE
-A C expression for the size in bits of the type @code{long} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac ADA_LONG_TYPE_SIZE
-On some machines, the size used for the Ada equivalent of the type
-@code{long} by a native Ada compiler differs from that used by C@. In
-that situation, define this macro to be a C expression to be used for
-the size of that type. If you don't define this, the default is the
-value of @code{LONG_TYPE_SIZE}.
-@end defmac
-
-@defmac LONG_LONG_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long} on the
-target machine. If you don't define this, the default is two
-words. If you want to support GNU Ada on your machine, the value of this
-macro must be at least 64.
-@end defmac
-
-@defmac CHAR_TYPE_SIZE
-A C expression for the size in bits of the type @code{char} on the
-target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac BOOL_TYPE_SIZE
-A C expression for the size in bits of the C++ type @code{bool} and
-C99 type @code{_Bool} on the target machine. If you don't define
-this, and you probably shouldn't, the default is @code{CHAR_TYPE_SIZE}.
-@end defmac
-
-@defmac FLOAT_TYPE_SIZE
-A C expression for the size in bits of the type @code{float} on the
-target machine. If you don't define this, the default is one word.
-@end defmac
-
-@defmac DOUBLE_TYPE_SIZE
-A C expression for the size in bits of the type @code{double} on the
-target machine. If you don't define this, the default is two
-words.
-@end defmac
-
-@defmac LONG_DOUBLE_TYPE_SIZE
-A C expression for the size in bits of the type @code{long double} on
-the target machine. If you don't define this, the default is two
-words.
-@end defmac
-
-@defmac SHORT_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{short _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT}.
-@end defmac
-
-@defmac FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{_Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 2}.
-@end defmac
-
-@defmac LONG_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{long _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 4}.
-@end defmac
-
-@defmac LONG_LONG_FRACT_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long _Fract} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 8}.
-@end defmac
-
-@defmac SHORT_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{short _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 2}.
-@end defmac
-
-@defmac ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{_Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 4}.
-@end defmac
-
-@defmac LONG_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{long _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 8}.
-@end defmac
-
-@defmac LONG_LONG_ACCUM_TYPE_SIZE
-A C expression for the size in bits of the type @code{long long _Accum} on
-the target machine. If you don't define this, the default is
-@code{BITS_PER_UNIT * 16}.
-@end defmac
-
-@defmac LIBGCC2_GNU_PREFIX
-This macro corresponds to the @code{TARGET_LIBFUNC_GNU_PREFIX} target
-hook and should be defined if that hook is overriden to be true. It
-causes function names in libgcc to be changed to use a @code{__gnu_}
-prefix for their name rather than the default @code{__}. A port which
-uses this macro should also arrange to use @file{t-gnu-prefix} in
-the libgcc @file{config.host}.
-@end defmac
-
-@defmac WIDEST_HARDWARE_FP_SIZE
-A C expression for the size in bits of the widest floating-point format
-supported by the hardware. If you define this macro, you must specify a
-value less than or equal to the value of @code{LONG_DOUBLE_TYPE_SIZE}.
-If you do not define this macro, the value of @code{LONG_DOUBLE_TYPE_SIZE}
-is the default.
-@end defmac
-
-@defmac DEFAULT_SIGNED_CHAR
-An expression whose value is 1 or 0, according to whether the type
-@code{char} should be signed or unsigned by default. The user can
-always override this default with the options @option{-fsigned-char}
-and @option{-funsigned-char}.
-@end defmac
-
-@hook TARGET_DEFAULT_SHORT_ENUMS
-
-@defmac SIZE_TYPE
-A C expression for a string describing the name of the data type to use
-for size values. The typedef name @code{size_t} is defined using the
-contents of the string.
-
-The string can contain more than one keyword. If so, separate them with
-spaces, and write first any length keyword, then @code{unsigned} if
-appropriate, and finally @code{int}. The string must exactly match one
-of the data type names defined in the function
-@code{c_common_nodes_and_builtins} in the file @file{c-family/c-common.cc}.
-You may not omit @code{int} or change the order---that would cause the
-compiler to crash on startup.
-
-If you don't define this macro, the default is @code{"long unsigned
-int"}.
-@end defmac
-
-@defmac SIZETYPE
-GCC defines internal types (@code{sizetype}, @code{ssizetype},
-@code{bitsizetype} and @code{sbitsizetype}) for expressions
-dealing with size. This macro is a C expression for a string describing
-the name of the data type from which the precision of @code{sizetype}
-is extracted.
-
-The string has the same restrictions as @code{SIZE_TYPE} string.
-
-If you don't define this macro, the default is @code{SIZE_TYPE}.
-@end defmac
-
-@defmac PTRDIFF_TYPE
-A C expression for a string describing the name of the data type to use
-for the result of subtracting two pointers. The typedef name
-@code{ptrdiff_t} is defined using the contents of the string. See
-@code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is @code{"long int"}.
-@end defmac
-
-@defmac WCHAR_TYPE
-A C expression for a string describing the name of the data type to use
-for wide characters. The typedef name @code{wchar_t} is defined using
-the contents of the string. See @code{SIZE_TYPE} above for more
-information.
-
-If you don't define this macro, the default is @code{"int"}.
-@end defmac
-
-@defmac WCHAR_TYPE_SIZE
-A C expression for the size in bits of the data type for wide
-characters. This is used in @code{cpp}, which cannot make use of
-@code{WCHAR_TYPE}.
-@end defmac
-
-@defmac WINT_TYPE
-A C expression for a string describing the name of the data type to
-use for wide characters passed to @code{printf} and returned from
-@code{getwc}. The typedef name @code{wint_t} is defined using the
-contents of the string. See @code{SIZE_TYPE} above for more
-information.
-
-If you don't define this macro, the default is @code{"unsigned int"}.
-@end defmac
-
-@defmac INTMAX_TYPE
-A C expression for a string describing the name of the data type that
-can represent any value of any standard or extended signed integer type.
-The typedef name @code{intmax_t} is defined using the contents of the
-string. See @code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is the first of
-@code{"int"}, @code{"long int"}, or @code{"long long int"} that has as
-much precision as @code{long long int}.
-@end defmac
-
-@defmac UINTMAX_TYPE
-A C expression for a string describing the name of the data type that
-can represent any value of any standard or extended unsigned integer
-type. The typedef name @code{uintmax_t} is defined using the contents
-of the string. See @code{SIZE_TYPE} above for more information.
-
-If you don't define this macro, the default is the first of
-@code{"unsigned int"}, @code{"long unsigned int"}, or @code{"long long
-unsigned int"} that has as much precision as @code{long long unsigned
-int}.
-@end defmac
-
-@defmac SIG_ATOMIC_TYPE
-@defmacx INT8_TYPE
-@defmacx INT16_TYPE
-@defmacx INT32_TYPE
-@defmacx INT64_TYPE
-@defmacx UINT8_TYPE
-@defmacx UINT16_TYPE
-@defmacx UINT32_TYPE
-@defmacx UINT64_TYPE
-@defmacx INT_LEAST8_TYPE
-@defmacx INT_LEAST16_TYPE
-@defmacx INT_LEAST32_TYPE
-@defmacx INT_LEAST64_TYPE
-@defmacx UINT_LEAST8_TYPE
-@defmacx UINT_LEAST16_TYPE
-@defmacx UINT_LEAST32_TYPE
-@defmacx UINT_LEAST64_TYPE
-@defmacx INT_FAST8_TYPE
-@defmacx INT_FAST16_TYPE
-@defmacx INT_FAST32_TYPE
-@defmacx INT_FAST64_TYPE
-@defmacx UINT_FAST8_TYPE
-@defmacx UINT_FAST16_TYPE
-@defmacx UINT_FAST32_TYPE
-@defmacx UINT_FAST64_TYPE
-@defmacx INTPTR_TYPE
-@defmacx UINTPTR_TYPE
-C expressions for the standard types @code{sig_atomic_t},
-@code{int8_t}, @code{int16_t}, @code{int32_t}, @code{int64_t},
-@code{uint8_t}, @code{uint16_t}, @code{uint32_t}, @code{uint64_t},
-@code{int_least8_t}, @code{int_least16_t}, @code{int_least32_t},
-@code{int_least64_t}, @code{uint_least8_t}, @code{uint_least16_t},
-@code{uint_least32_t}, @code{uint_least64_t}, @code{int_fast8_t},
-@code{int_fast16_t}, @code{int_fast32_t}, @code{int_fast64_t},
-@code{uint_fast8_t}, @code{uint_fast16_t}, @code{uint_fast32_t},
-@code{uint_fast64_t}, @code{intptr_t}, and @code{uintptr_t}. See
-@code{SIZE_TYPE} above for more information.
-
-If any of these macros evaluates to a null pointer, the corresponding
-type is not supported; if GCC is configured to provide
-@code{<stdint.h>} in such a case, the header provided may not conform
-to C99, depending on the type in question. The defaults for all of
-these macros are null pointers.
-@end defmac
-
-@defmac TARGET_PTRMEMFUNC_VBIT_LOCATION
-The C++ compiler represents a pointer-to-member-function with a struct
-that looks like:
-
-@smallexample
- struct @{
- union @{
- void (*fn)();
- ptrdiff_t vtable_index;
- @};
- ptrdiff_t delta;
- @};
-@end smallexample
-
-@noindent
-The C++ compiler must use one bit to indicate whether the function that
-will be called through a pointer-to-member-function is virtual.
-Normally, we assume that the low-order bit of a function pointer must
-always be zero. Then, by ensuring that the vtable_index is odd, we can
-distinguish which variant of the union is in use. But, on some
-platforms function pointers can be odd, and so this doesn't work. In
-that case, we use the low-order bit of the @code{delta} field, and shift
-the remainder of the @code{delta} field to the left.
-
-GCC will automatically make the right selection about where to store
-this bit using the @code{FUNCTION_BOUNDARY} setting for your platform.
-However, some platforms such as ARM/Thumb have @code{FUNCTION_BOUNDARY}
-set such that functions always start at even addresses, but the lowest
-bit of pointers to functions indicate whether the function at that
-address is in ARM or Thumb mode. If this is the case of your
-architecture, you should define this macro to
-@code{ptrmemfunc_vbit_in_delta}.
-
-In general, you should not have to define this macro. On architectures
-in which function addresses are always even, according to
-@code{FUNCTION_BOUNDARY}, GCC will automatically define this macro to
-@code{ptrmemfunc_vbit_in_pfn}.
-@end defmac
-
-@defmac TARGET_VTABLE_USES_DESCRIPTORS
-Normally, the C++ compiler uses function pointers in vtables. This
-macro allows the target to change to use ``function descriptors''
-instead. Function descriptors are found on targets for whom a
-function pointer is actually a small data structure. Normally the
-data structure consists of the actual code address plus a data
-pointer to which the function's data is relative.
-
-If vtables are used, the value of this macro should be the number
-of words that the function descriptor occupies.
-@end defmac
-
-@defmac TARGET_VTABLE_ENTRY_ALIGN
-By default, the vtable entries are void pointers, the so the alignment
-is the same as pointer alignment. The value of this macro specifies
-the alignment of the vtable entry in bits. It should be defined only
-when special alignment is necessary. */
-@end defmac
-
-@defmac TARGET_VTABLE_DATA_ENTRY_DISTANCE
-There are a few non-descriptor entries in the vtable at offsets below
-zero. If these entries must be padded (say, to preserve the alignment
-specified by @code{TARGET_VTABLE_ENTRY_ALIGN}), set this to the number
-of words in each data entry.
-@end defmac
-
-@node Registers
-@section Register Usage
-@cindex register usage
-
-This section explains how to describe what registers the target machine
-has, and how (in general) they can be used.
-
-The description of which registers a specific instruction can use is
-done with register classes; see @ref{Register Classes}. For information
-on using registers to access a stack frame, see @ref{Frame Registers}.
-For passing values in registers, see @ref{Register Arguments}.
-For returning values in registers, see @ref{Scalar Return}.
-
-@menu
-* Register Basics:: Number and kinds of registers.
-* Allocation Order:: Order in which registers are allocated.
-* Values in Registers:: What kinds of values each reg can hold.
-* Leaf Functions:: Renumbering registers for leaf functions.
-* Stack Registers:: Handling a register stack such as 80387.
-@end menu
-
-@node Register Basics
-@subsection Basic Characteristics of Registers
-
-@c prevent bad page break with this line
-Registers have various characteristics.
-
-@defmac FIRST_PSEUDO_REGISTER
-Number of hardware registers known to the compiler. They receive
-numbers 0 through @code{FIRST_PSEUDO_REGISTER-1}; thus, the first
-pseudo register's number really is assigned the number
-@code{FIRST_PSEUDO_REGISTER}.
-@end defmac
-
-@defmac FIXED_REGISTERS
-@cindex fixed register
-An initializer that says which registers are used for fixed purposes
-all throughout the compiled code and are therefore not available for
-general allocation. These would include the stack pointer, the frame
-pointer (except on machines where that can be used as a general
-register when no frame pointer is needed), the program counter on
-machines where that is considered one of the addressable registers,
-and any other numbered register with a standard use.
-
-This information is expressed as a sequence of numbers, separated by
-commas and surrounded by braces. The @var{n}th number is 1 if
-register @var{n} is fixed, 0 otherwise.
-
-The table initialized from this macro, and the table initialized by
-the following one, may be overridden at run time either automatically,
-by the actions of the macro @code{CONDITIONAL_REGISTER_USAGE}, or by
-the user with the command options @option{-ffixed-@var{reg}},
-@option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}.
-@end defmac
-
-@defmac CALL_USED_REGISTERS
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-Like @code{FIXED_REGISTERS} but has 1 for each register that is
-clobbered (in general) by function calls as well as for fixed
-registers. This macro therefore identifies the registers that are not
-available for general allocation of values that must live across
-function calls.
-
-If a register has 0 in @code{CALL_USED_REGISTERS}, the compiler
-automatically saves it on function entry and restores it on function
-exit, if the register is used within the function.
-
-Exactly one of @code{CALL_USED_REGISTERS} and @code{CALL_REALLY_USED_REGISTERS}
-must be defined. Modern ports should define @code{CALL_REALLY_USED_REGISTERS}.
-@end defmac
-
-@defmac CALL_REALLY_USED_REGISTERS
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-Like @code{CALL_USED_REGISTERS} except this macro doesn't require
-that the entire set of @code{FIXED_REGISTERS} be included.
-(@code{CALL_USED_REGISTERS} must be a superset of @code{FIXED_REGISTERS}).
-
-Exactly one of @code{CALL_USED_REGISTERS} and @code{CALL_REALLY_USED_REGISTERS}
-must be defined. Modern ports should define @code{CALL_REALLY_USED_REGISTERS}.
-@end defmac
-
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-@hook TARGET_FNTYPE_ABI
-
-@hook TARGET_INSN_CALLEE_ABI
-
-@cindex call-used register
-@cindex call-clobbered register
-@cindex call-saved register
-@hook TARGET_HARD_REGNO_CALL_PART_CLOBBERED
-
-@hook TARGET_GET_MULTILIB_ABI_NAME
-
-@findex fixed_regs
-@findex call_used_regs
-@findex global_regs
-@findex reg_names
-@findex reg_class_contents
-@hook TARGET_CONDITIONAL_REGISTER_USAGE
-
-@defmac INCOMING_REGNO (@var{out})
-Define this macro if the target machine has register windows. This C
-expression returns the register number as seen by the called function
-corresponding to the register number @var{out} as seen by the calling
-function. Return @var{out} if register number @var{out} is not an
-outbound register.
-@end defmac
-
-@defmac OUTGOING_REGNO (@var{in})
-Define this macro if the target machine has register windows. This C
-expression returns the register number as seen by the calling function
-corresponding to the register number @var{in} as seen by the called
-function. Return @var{in} if register number @var{in} is not an inbound
-register.
-@end defmac
-
-@defmac LOCAL_REGNO (@var{regno})
-Define this macro if the target machine has register windows. This C
-expression returns true if the register is call-saved but is in the
-register window. Unlike most call-saved registers, such registers
-need not be explicitly restored on function exit or during non-local
-gotos.
-@end defmac
-
-@defmac PC_REGNUM
-If the program counter has a register number, define this as that
-register number. Otherwise, do not define it.
-@end defmac
-
-@node Allocation Order
-@subsection Order of Allocation of Registers
-@cindex order of register allocation
-@cindex register allocation order
-
-@c prevent bad page break with this line
-Registers are allocated in order.
-
-@defmac REG_ALLOC_ORDER
-If defined, an initializer for a vector of integers, containing the
-numbers of hard registers in the order in which GCC should prefer
-to use them (from most preferred to least).
-
-If this macro is not defined, registers are used lowest numbered first
-(all else being equal).
-
-One use of this macro is on machines where the highest numbered
-registers must always be saved and the save-multiple-registers
-instruction supports only sequences of consecutive registers. On such
-machines, define @code{REG_ALLOC_ORDER} to be an initializer that lists
-the highest numbered allocable register first.
-@end defmac
-
-@defmac ADJUST_REG_ALLOC_ORDER
-A C statement (sans semicolon) to choose the order in which to allocate
-hard registers for pseudo-registers local to a basic block.
-
-Store the desired register order in the array @code{reg_alloc_order}.
-Element 0 should be the register to allocate first; element 1, the next
-register; and so on.
-
-The macro body should not assume anything about the contents of
-@code{reg_alloc_order} before execution of the macro.
-
-On most machines, it is not necessary to define this macro.
-@end defmac
-
-@defmac HONOR_REG_ALLOC_ORDER
-Normally, IRA tries to estimate the costs for saving a register in the
-prologue and restoring it in the epilogue. This discourages it from
-using call-saved registers. If a machine wants to ensure that IRA
-allocates registers in the order given by REG_ALLOC_ORDER even if some
-call-saved registers appear earlier than call-used ones, then define this
-macro as a C expression to nonzero. Default is 0.
-@end defmac
-
-@defmac IRA_HARD_REGNO_ADD_COST_MULTIPLIER (@var{regno})
-In some case register allocation order is not enough for the
-Integrated Register Allocator (@acronym{IRA}) to generate a good code.
-If this macro is defined, it should return a floating point value
-based on @var{regno}. The cost of using @var{regno} for a pseudo will
-be increased by approximately the pseudo's usage frequency times the
-value returned by this macro. Not defining this macro is equivalent
-to having it always return @code{0.0}.
-
-On most machines, it is not necessary to define this macro.
-@end defmac
-
-@node Values in Registers
-@subsection How Values Fit in Registers
-
-This section discusses the macros that describe which kinds of values
-(specifically, which machine modes) each register can hold, and how many
-consecutive registers are needed for a given mode.
-
-@hook TARGET_HARD_REGNO_NREGS
-
-@defmac HARD_REGNO_NREGS_HAS_PADDING (@var{regno}, @var{mode})
-A C expression that is nonzero if a value of mode @var{mode}, stored
-in memory, ends with padding that causes it to take up more space than
-in registers starting at register number @var{regno} (as determined by
-multiplying GCC's notion of the size of the register when containing
-this mode by the number of registers returned by
-@code{TARGET_HARD_REGNO_NREGS}). By default this is zero.
-
-For example, if a floating-point value is stored in three 32-bit
-registers but takes up 128 bits in memory, then this would be
-nonzero.
-
-This macros only needs to be defined if there are cases where
-@code{subreg_get_info}
-would otherwise wrongly determine that a @code{subreg} can be
-represented by an offset to the register number, when in fact such a
-@code{subreg} would contain some of the padding not stored in
-registers and so not be representable.
-@end defmac
-
-@defmac HARD_REGNO_NREGS_WITH_PADDING (@var{regno}, @var{mode})
-For values of @var{regno} and @var{mode} for which
-@code{HARD_REGNO_NREGS_HAS_PADDING} returns nonzero, a C expression
-returning the greater number of registers required to hold the value
-including any padding. In the example above, the value would be four.
-@end defmac
-
-@defmac REGMODE_NATURAL_SIZE (@var{mode})
-Define this macro if the natural size of registers that hold values
-of mode @var{mode} is not the word size. It is a C expression that
-should give the natural size in bytes for the specified mode. It is
-used by the register allocator to try to optimize its results. This
-happens for example on SPARC 64-bit where the natural size of
-floating-point registers is still 32-bit.
-@end defmac
-
-@hook TARGET_HARD_REGNO_MODE_OK
-
-@defmac HARD_REGNO_RENAME_OK (@var{from}, @var{to})
-A C expression that is nonzero if it is OK to rename a hard register
-@var{from} to another hard register @var{to}.
-
-One common use of this macro is to prevent renaming of a register to
-another register that is not saved by a prologue in an interrupt
-handler.
-
-The default is always nonzero.
-@end defmac
-
-@hook TARGET_MODES_TIEABLE_P
-
-@hook TARGET_HARD_REGNO_SCRATCH_OK
-
-@defmac AVOID_CCMODE_COPIES
-Define this macro if the compiler should avoid copies to/from @code{CCmode}
-registers. You should only define this macro if support for copying to/from
-@code{CCmode} is incomplete.
-@end defmac
-
-@node Leaf Functions
-@subsection Handling Leaf Functions
-
-@cindex leaf functions
-@cindex functions, leaf
-On some machines, a leaf function (i.e., one which makes no calls) can run
-more efficiently if it does not make its own register window. Often this
-means it is required to receive its arguments in the registers where they
-are passed by the caller, instead of the registers where they would
-normally arrive.
-
-The special treatment for leaf functions generally applies only when
-other conditions are met; for example, often they may use only those
-registers for its own variables and temporaries. We use the term ``leaf
-function'' to mean a function that is suitable for this special
-handling, so that functions with no calls are not necessarily ``leaf
-functions''.
-
-GCC assigns register numbers before it knows whether the function is
-suitable for leaf function treatment. So it needs to renumber the
-registers in order to output a leaf function. The following macros
-accomplish this.
-
-@defmac LEAF_REGISTERS
-Name of a char vector, indexed by hard register number, which
-contains 1 for a register that is allowable in a candidate for leaf
-function treatment.
-
-If leaf function treatment involves renumbering the registers, then the
-registers marked here should be the ones before renumbering---those that
-GCC would ordinarily allocate. The registers which will actually be
-used in the assembler code, after renumbering, should not be marked with 1
-in this vector.
-
-Define this macro only if the target machine offers a way to optimize
-the treatment of leaf functions.
-@end defmac
-
-@defmac LEAF_REG_REMAP (@var{regno})
-A C expression whose value is the register number to which @var{regno}
-should be renumbered, when a function is treated as a leaf function.
-
-If @var{regno} is a register number which should not appear in a leaf
-function before renumbering, then the expression should yield @minus{}1, which
-will cause the compiler to abort.
-
-Define this macro only if the target machine offers a way to optimize the
-treatment of leaf functions, and registers need to be renumbered to do
-this.
-@end defmac
-
-@findex current_function_is_leaf
-@findex current_function_uses_only_leaf_regs
-@code{TARGET_ASM_FUNCTION_PROLOGUE} and
-@code{TARGET_ASM_FUNCTION_EPILOGUE} must usually treat leaf functions
-specially. They can test the C variable @code{current_function_is_leaf}
-which is nonzero for leaf functions. @code{current_function_is_leaf} is
-set prior to local register allocation and is valid for the remaining
-compiler passes. They can also test the C variable
-@code{current_function_uses_only_leaf_regs} which is nonzero for leaf
-functions which only use leaf registers.
-@code{current_function_uses_only_leaf_regs} is valid after all passes
-that modify the instructions have been run and is only useful if
-@code{LEAF_REGISTERS} is defined.
-@c changed this to fix overfull. ALSO: why the "it" at the beginning
-@c of the next paragraph?! --mew 2feb93
-
-@node Stack Registers
-@subsection Registers That Form a Stack
-
-There are special features to handle computers where some of the
-``registers'' form a stack. Stack registers are normally written by
-pushing onto the stack, and are numbered relative to the top of the
-stack.
-
-Currently, GCC can only handle one group of stack-like registers, and
-they must be consecutively numbered. Furthermore, the existing
-support for stack-like registers is specific to the 80387 floating
-point coprocessor. If you have a new architecture that uses
-stack-like registers, you will need to do substantial work on
-@file{reg-stack.cc} and write your machine description to cooperate
-with it, as well as defining these macros.
-
-@defmac STACK_REGS
-Define this if the machine has any stack-like registers.
-@end defmac
-
-@defmac STACK_REG_COVER_CLASS
-This is a cover class containing the stack registers. Define this if
-the machine has any stack-like registers.
-@end defmac
-
-@defmac FIRST_STACK_REG
-The number of the first stack-like register. This one is the top
-of the stack.
-@end defmac
-
-@defmac LAST_STACK_REG
-The number of the last stack-like register. This one is the bottom of
-the stack.
-@end defmac
-
-@node Register Classes
-@section Register Classes
-@cindex register class definitions
-@cindex class definitions, register
-
-On many machines, the numbered registers are not all equivalent.
-For example, certain registers may not be allowed for indexed addressing;
-certain registers may not be allowed in some instructions. These machine
-restrictions are described to the compiler using @dfn{register classes}.
-
-You define a number of register classes, giving each one a name and saying
-which of the registers belong to it. Then you can specify register classes
-that are allowed as operands to particular instruction patterns.
-
-@findex ALL_REGS
-@findex NO_REGS
-In general, each register will belong to several classes. In fact, one
-class must be named @code{ALL_REGS} and contain all the registers. Another
-class must be named @code{NO_REGS} and contain no registers. Often the
-union of two classes will be another class; however, this is not required.
-
-@findex GENERAL_REGS
-One of the classes must be named @code{GENERAL_REGS}. There is nothing
-terribly special about the name, but the operand constraint letters
-@samp{r} and @samp{g} specify this class. If @code{GENERAL_REGS} is
-the same as @code{ALL_REGS}, just define it as a macro which expands
-to @code{ALL_REGS}.
-
-Order the classes so that if class @var{x} is contained in class @var{y}
-then @var{x} has a lower class number than @var{y}.
-
-The way classes other than @code{GENERAL_REGS} are specified in operand
-constraints is through machine-dependent operand constraint letters.
-You can define such letters to correspond to various classes, then use
-them in operand constraints.
-
-You must define the narrowest register classes for allocatable
-registers, so that each class either has no subclasses, or that for
-some mode, the move cost between registers within the class is
-cheaper than moving a register in the class to or from memory
-(@pxref{Costs}).
-
-You should define a class for the union of two classes whenever some
-instruction allows both classes. For example, if an instruction allows
-either a floating point (coprocessor) register or a general register for a
-certain operand, you should define a class @code{FLOAT_OR_GENERAL_REGS}
-which includes both of them. Otherwise you will get suboptimal code,
-or even internal compiler errors when reload cannot find a register in the
-class computed via @code{reg_class_subunion}.
-
-You must also specify certain redundant information about the register
-classes: for each class, which classes contain it and which ones are
-contained in it; for each pair of classes, the largest class contained
-in their union.
-
-When a value occupying several consecutive registers is expected in a
-certain class, all the registers used must belong to that class.
-Therefore, register classes cannot be used to enforce a requirement for
-a register pair to start with an even-numbered register. The way to
-specify this requirement is with @code{TARGET_HARD_REGNO_MODE_OK}.
-
-Register classes used for input-operands of bitwise-and or shift
-instructions have a special requirement: each such class must have, for
-each fixed-point machine mode, a subclass whose registers can transfer that
-mode to or from memory. For example, on some machines, the operations for
-single-byte values (@code{QImode}) are limited to certain registers. When
-this is so, each register class that is used in a bitwise-and or shift
-instruction must have a subclass consisting of registers from which
-single-byte values can be loaded or stored. This is so that
-@code{PREFERRED_RELOAD_CLASS} can always have a possible value to return.
-
-@deftp {Data type} {enum reg_class}
-An enumerated type that must be defined with all the register class names
-as enumerated values. @code{NO_REGS} must be first. @code{ALL_REGS}
-must be the last register class, followed by one more enumerated value,
-@code{LIM_REG_CLASSES}, which is not a register class but rather
-tells how many classes there are.
-
-Each register class has a number, which is the value of casting
-the class name to type @code{int}. The number serves as an index
-in many of the tables described below.
-@end deftp
-
-@defmac N_REG_CLASSES
-The number of distinct register classes, defined as follows:
-
-@smallexample
-#define N_REG_CLASSES (int) LIM_REG_CLASSES
-@end smallexample
-@end defmac
-
-@defmac REG_CLASS_NAMES
-An initializer containing the names of the register classes as C string
-constants. These names are used in writing some of the debugging dumps.
-@end defmac
-
-@defmac REG_CLASS_CONTENTS
-An initializer containing the contents of the register classes, as integers
-which are bit masks. The @var{n}th integer specifies the contents of class
-@var{n}. The way the integer @var{mask} is interpreted is that
-register @var{r} is in the class if @code{@var{mask} & (1 << @var{r})} is 1.
-
-When the machine has more than 32 registers, an integer does not suffice.
-Then the integers are replaced by sub-initializers, braced groupings containing
-several integers. Each sub-initializer must be suitable as an initializer
-for the type @code{HARD_REG_SET} which is defined in @file{hard-reg-set.h}.
-In this situation, the first integer in each sub-initializer corresponds to
-registers 0 through 31, the second integer to registers 32 through 63, and
-so on.
-@end defmac
-
-@defmac REGNO_REG_CLASS (@var{regno})
-A C expression whose value is a register class containing hard register
-@var{regno}. In general there is more than one such class; choose a class
-which is @dfn{minimal}, meaning that no smaller class also contains the
-register.
-@end defmac
-
-@defmac BASE_REG_CLASS
-A macro whose definition is the name of the class to which a valid
-base register must belong. A base register is one used in an address
-which is the register value plus a displacement.
-@end defmac
-
-@defmac MODE_BASE_REG_CLASS (@var{mode})
-This is a variation of the @code{BASE_REG_CLASS} macro which allows
-the selection of a base register in a mode dependent manner. If
-@var{mode} is VOIDmode then it should return the same value as
-@code{BASE_REG_CLASS}.
-@end defmac
-
-@defmac MODE_BASE_REG_REG_CLASS (@var{mode})
-A C expression whose value is the register class to which a valid
-base register must belong in order to be used in a base plus index
-register address. You should define this macro if base plus index
-addresses have different requirements than other base register uses.
-@end defmac
-
-@defmac MODE_CODE_BASE_REG_CLASS (@var{mode}, @var{address_space}, @var{outer_code}, @var{index_code})
-A C expression whose value is the register class to which a valid
-base register for a memory reference in mode @var{mode} to address
-space @var{address_space} must belong. @var{outer_code} and @var{index_code}
-define the context in which the base register occurs. @var{outer_code} is
-the code of the immediately enclosing expression (@code{MEM} for the top level
-of an address, @code{ADDRESS} for something that occurs in an
-@code{address_operand}). @var{index_code} is the code of the corresponding
-index expression if @var{outer_code} is @code{PLUS}; @code{SCRATCH} otherwise.
-@end defmac
-
-@defmac INDEX_REG_CLASS
-A macro whose definition is the name of the class to which a valid
-index register must belong. An index register is one used in an
-address where its value is either multiplied by a scale factor or
-added to another register (as well as added to a displacement).
-@end defmac
-
-@defmac REGNO_OK_FOR_BASE_P (@var{num})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as a base register in operand addresses.
-@end defmac
-
-@defmac REGNO_MODE_OK_FOR_BASE_P (@var{num}, @var{mode})
-A C expression that is just like @code{REGNO_OK_FOR_BASE_P}, except that
-that expression may examine the mode of the memory reference in
-@var{mode}. You should define this macro if the mode of the memory
-reference affects whether a register may be used as a base register. If
-you define this macro, the compiler will use it instead of
-@code{REGNO_OK_FOR_BASE_P}. The mode may be @code{VOIDmode} for
-addresses that appear outside a @code{MEM}, i.e., as an
-@code{address_operand}.
-@end defmac
-
-@defmac REGNO_MODE_OK_FOR_REG_BASE_P (@var{num}, @var{mode})
-A C expression which is nonzero if register number @var{num} is suitable for
-use as a base register in base plus index operand addresses, accessing
-memory in mode @var{mode}. It may be either a suitable hard register or a
-pseudo register that has been allocated such a hard register. You should
-define this macro if base plus index addresses have different requirements
-than other base register uses.
-
-Use of this macro is deprecated; please use the more general
-@code{REGNO_MODE_CODE_OK_FOR_BASE_P}.
-@end defmac
-
-@defmac REGNO_MODE_CODE_OK_FOR_BASE_P (@var{num}, @var{mode}, @var{address_space}, @var{outer_code}, @var{index_code})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as a base register in operand addresses, accessing
-memory in mode @var{mode} in address space @var{address_space}.
-This is similar to @code{REGNO_MODE_OK_FOR_BASE_P}, except
-that that expression may examine the context in which the register
-appears in the memory reference. @var{outer_code} is the code of the
-immediately enclosing expression (@code{MEM} if at the top level of the
-address, @code{ADDRESS} for something that occurs in an
-@code{address_operand}). @var{index_code} is the code of the
-corresponding index expression if @var{outer_code} is @code{PLUS};
-@code{SCRATCH} otherwise. The mode may be @code{VOIDmode} for addresses
-that appear outside a @code{MEM}, i.e., as an @code{address_operand}.
-@end defmac
-
-@defmac REGNO_OK_FOR_INDEX_P (@var{num})
-A C expression which is nonzero if register number @var{num} is
-suitable for use as an index register in operand addresses. It may be
-either a suitable hard register or a pseudo register that has been
-allocated such a hard register.
-
-The difference between an index register and a base register is that
-the index register may be scaled. If an address involves the sum of
-two registers, neither one of them scaled, then either one may be
-labeled the ``base'' and the other the ``index''; but whichever
-labeling is used must fit the machine's constraints of which registers
-may serve in each capacity. The compiler will try both labelings,
-looking for one that is valid, and will reload one or both registers
-only if neither labeling works.
-@end defmac
-
-@hook TARGET_PREFERRED_RENAME_CLASS
-
-@hook TARGET_PREFERRED_RELOAD_CLASS
-
-@defmac PREFERRED_RELOAD_CLASS (@var{x}, @var{class})
-A C expression that places additional restrictions on the register class
-to use when it is necessary to copy value @var{x} into a register in class
-@var{class}. The value is a register class; perhaps @var{class}, or perhaps
-another, smaller class. On many machines, the following definition is
-safe:
-
-@smallexample
-#define PREFERRED_RELOAD_CLASS(X,CLASS) CLASS
-@end smallexample
-
-Sometimes returning a more restrictive class makes better code. For
-example, on the 68000, when @var{x} is an integer constant that is in range
-for a @samp{moveq} instruction, the value of this macro is always
-@code{DATA_REGS} as long as @var{class} includes the data registers.
-Requiring a data register guarantees that a @samp{moveq} will be used.
-
-One case where @code{PREFERRED_RELOAD_CLASS} must not return
-@var{class} is if @var{x} is a legitimate constant which cannot be
-loaded into some register class. By returning @code{NO_REGS} you can
-force @var{x} into a memory location. For example, rs6000 can load
-immediate values into general-purpose registers, but does not have an
-instruction for loading an immediate value into a floating-point
-register, so @code{PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when
-@var{x} is a floating-point constant. If the constant cannot be loaded
-into any kind of register, code generation will be better if
-@code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead
-of using @code{TARGET_PREFERRED_RELOAD_CLASS}.
-
-If an insn has pseudos in it after register allocation, reload will go
-through the alternatives and call repeatedly @code{PREFERRED_RELOAD_CLASS}
-to find the best one. Returning @code{NO_REGS}, in this case, makes
-reload add a @code{!} in front of the constraint: the x86 back-end uses
-this feature to discourage usage of 387 registers when math is done in
-the SSE registers (and vice versa).
-@end defmac
-
-@hook TARGET_PREFERRED_OUTPUT_RELOAD_CLASS
-
-@defmac LIMIT_RELOAD_CLASS (@var{mode}, @var{class})
-A C expression that places additional restrictions on the register class
-to use when it is necessary to be able to hold a value of mode
-@var{mode} in a reload register for which class @var{class} would
-ordinarily be used.
-
-Unlike @code{PREFERRED_RELOAD_CLASS}, this macro should be used when
-there are certain modes that simply cannot go in certain reload classes.
-
-The value is a register class; perhaps @var{class}, or perhaps another,
-smaller class.
-
-Don't define this macro unless the target machine has limitations which
-require the macro to do something nontrivial.
-@end defmac
-
-@hook TARGET_SECONDARY_RELOAD
-
-@defmac SECONDARY_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@defmacx SECONDARY_INPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-@defmacx SECONDARY_OUTPUT_RELOAD_CLASS (@var{class}, @var{mode}, @var{x})
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_SECONDARY_RELOAD} instead.
-
-These are obsolete macros, replaced by the @code{TARGET_SECONDARY_RELOAD}
-target hook. Older ports still define these macros to indicate to the
-reload phase that it may
-need to allocate at least one register for a reload in addition to the
-register to contain the data. Specifically, if copying @var{x} to a
-register @var{class} in @var{mode} requires an intermediate register,
-you were supposed to define @code{SECONDARY_INPUT_RELOAD_CLASS} to return the
-largest register class all of whose registers can be used as
-intermediate registers or scratch registers.
-
-If copying a register @var{class} in @var{mode} to @var{x} requires an
-intermediate or scratch register, @code{SECONDARY_OUTPUT_RELOAD_CLASS}
-was supposed to be defined to return the largest register
-class required. If the
-requirements for input and output reloads were the same, the macro
-@code{SECONDARY_RELOAD_CLASS} should have been used instead of defining both
-macros identically.
-
-The values returned by these macros are often @code{GENERAL_REGS}.
-Return @code{NO_REGS} if no spare register is needed; i.e., if @var{x}
-can be directly copied to or from a register of @var{class} in
-@var{mode} without requiring a scratch register. Do not define this
-macro if it would always return @code{NO_REGS}.
-
-If a scratch register is required (either with or without an
-intermediate register), you were supposed to define patterns for
-@samp{reload_in@var{m}} or @samp{reload_out@var{m}}, as required
-(@pxref{Standard Names}. These patterns, which were normally
-implemented with a @code{define_expand}, should be similar to the
-@samp{mov@var{m}} patterns, except that operand 2 is the scratch
-register.
-
-These patterns need constraints for the reload register and scratch
-register that
-contain a single register class. If the original reload register (whose
-class is @var{class}) can meet the constraint given in the pattern, the
-value returned by these macros is used for the class of the scratch
-register. Otherwise, two additional reload registers are required.
-Their classes are obtained from the constraints in the insn pattern.
-
-@var{x} might be a pseudo-register or a @code{subreg} of a
-pseudo-register, which could either be in a hard register or in memory.
-Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is
-in memory and the hard register number if it is in a register.
-
-These macros should not be used in the case where a particular class of
-registers can only be copied to memory and not to another class of
-registers. In that case, secondary reload registers are not needed and
-would not be helpful. Instead, a stack location must be used to perform
-the copy and the @code{mov@var{m}} pattern should use memory as an
-intermediate storage. This case often occurs between floating-point and
-general registers.
-@end defmac
-
-@hook TARGET_SECONDARY_MEMORY_NEEDED
-
-@defmac SECONDARY_MEMORY_NEEDED_RTX (@var{mode})
-Normally when @code{TARGET_SECONDARY_MEMORY_NEEDED} is defined, the compiler
-allocates a stack slot for a memory location needed for register copies.
-If this macro is defined, the compiler instead uses the memory location
-defined by this macro.
-
-Do not define this macro if you do not define
-@code{TARGET_SECONDARY_MEMORY_NEEDED}.
-@end defmac
-
-@hook TARGET_SECONDARY_MEMORY_NEEDED_MODE
-
-@hook TARGET_SELECT_EARLY_REMAT_MODES
-
-@hook TARGET_CLASS_LIKELY_SPILLED_P
-
-@hook TARGET_CLASS_MAX_NREGS
-
-@defmac CLASS_MAX_NREGS (@var{class}, @var{mode})
-A C expression for the maximum number of consecutive registers
-of class @var{class} needed to hold a value of mode @var{mode}.
-
-This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}. In fact,
-the value of the macro @code{CLASS_MAX_NREGS (@var{class}, @var{mode})}
-should be the maximum value of @code{TARGET_HARD_REGNO_NREGS (@var{regno},
-@var{mode})} for all @var{regno} values in the class @var{class}.
-
-This macro helps control the handling of multiple-word values
-in the reload pass.
-@end defmac
-
-@hook TARGET_CAN_CHANGE_MODE_CLASS
-
-@hook TARGET_IRA_CHANGE_PSEUDO_ALLOCNO_CLASS
-
-@hook TARGET_LRA_P
-
-@hook TARGET_REGISTER_PRIORITY
-
-@hook TARGET_REGISTER_USAGE_LEVELING_P
-
-@hook TARGET_DIFFERENT_ADDR_DISPLACEMENT_P
-
-@hook TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P
-
-@hook TARGET_LEGITIMIZE_ADDRESS_DISPLACEMENT
-
-@hook TARGET_SPILL_CLASS
-
-@hook TARGET_ADDITIONAL_ALLOCNO_CLASS_P
-
-@hook TARGET_CSTORE_MODE
-
-@hook TARGET_COMPUTE_PRESSURE_CLASSES
-
-@node Stack and Calling
-@section Stack Layout and Calling Conventions
-@cindex calling conventions
-
-@c prevent bad page break with this line
-This describes the stack layout and calling conventions.
-
-@menu
-* Frame Layout::
-* Exception Handling::
-* Stack Checking::
-* Frame Registers::
-* Elimination::
-* Stack Arguments::
-* Register Arguments::
-* Scalar Return::
-* Aggregate Return::
-* Caller Saves::
-* Function Entry::
-* Profiling::
-* Tail Calls::
-* Shrink-wrapping separate components::
-* Stack Smashing Protection::
-* Miscellaneous Register Hooks::
-@end menu
-
-@node Frame Layout
-@subsection Basic Stack Layout
-@cindex stack frame layout
-@cindex frame layout
-
-@c prevent bad page break with this line
-Here is the basic stack layout.
-
-@defmac STACK_GROWS_DOWNWARD
-Define this macro to be true if pushing a word onto the stack moves the stack
-pointer to a smaller address, and false otherwise.
-@end defmac
-
-@defmac STACK_PUSH_CODE
-This macro defines the operation used when something is pushed
-on the stack. In RTL, a push operation will be
-@code{(set (mem (STACK_PUSH_CODE (reg sp))) @dots{})}
-
-The choices are @code{PRE_DEC}, @code{POST_DEC}, @code{PRE_INC},
-and @code{POST_INC}. Which of these is correct depends on
-the stack direction and on whether the stack pointer points
-to the last item on the stack or whether it points to the
-space for the next item on the stack.
-
-The default is @code{PRE_DEC} when @code{STACK_GROWS_DOWNWARD} is
-true, which is almost always right, and @code{PRE_INC} otherwise,
-which is often wrong.
-@end defmac
-
-@defmac FRAME_GROWS_DOWNWARD
-Define this macro to nonzero value if the addresses of local variable slots
-are at negative offsets from the frame pointer.
-@end defmac
-
-@defmac ARGS_GROW_DOWNWARD
-Define this macro if successive arguments to a function occupy decreasing
-addresses on the stack.
-@end defmac
-
-@hook TARGET_STARTING_FRAME_OFFSET
-
-@defmac STACK_ALIGNMENT_NEEDED
-Define to zero to disable final alignment of the stack during reload.
-The nonzero default for this macro is suitable for most ports.
-
-On ports where @code{TARGET_STARTING_FRAME_OFFSET} is nonzero or where there
-is a register save block following the local block that doesn't require
-alignment to @code{STACK_BOUNDARY}, it may be beneficial to disable
-stack alignment and do it in the backend.
-@end defmac
-
-@defmac STACK_POINTER_OFFSET
-Offset from the stack pointer register to the first location at which
-outgoing arguments are placed. If not specified, the default value of
-zero is used. This is the proper value for most machines.
-
-If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
-the first location at which outgoing arguments are placed.
-@end defmac
-
-@defmac FIRST_PARM_OFFSET (@var{fundecl})
-Offset from the argument pointer register to the first argument's
-address. On some machines it may depend on the data type of the
-function.
-
-If @code{ARGS_GROW_DOWNWARD}, this is the offset to the location above
-the first argument's address.
-@end defmac
-
-@defmac STACK_DYNAMIC_OFFSET (@var{fundecl})
-Offset from the stack pointer register to an item dynamically allocated
-on the stack, e.g., by @code{alloca}.
-
-The default value for this macro is @code{STACK_POINTER_OFFSET} plus the
-length of the outgoing arguments. The default is correct for most
-machines. See @file{function.cc} for details.
-@end defmac
-
-@defmac INITIAL_FRAME_ADDRESS_RTX
-A C expression whose value is RTL representing the address of the initial
-stack frame. This address is passed to @code{RETURN_ADDR_RTX} and
-@code{DYNAMIC_CHAIN_ADDRESS}. If you don't define this macro, a reasonable
-default value will be used. Define this macro in order to make frame pointer
-elimination work in the presence of @code{__builtin_frame_address (count)} and
-@code{__builtin_return_address (count)} for @code{count} not equal to zero.
-@end defmac
-
-@defmac DYNAMIC_CHAIN_ADDRESS (@var{frameaddr})
-A C expression whose value is RTL representing the address in a stack
-frame where the pointer to the caller's frame is stored. Assume that
-@var{frameaddr} is an RTL expression for the address of the stack frame
-itself.
-
-If you don't define this macro, the default is to return the value
-of @var{frameaddr}---that is, the stack frame address is also the
-address of the stack word that points to the previous frame.
-@end defmac
-
-@defmac SETUP_FRAME_ADDRESSES
-A C expression that produces the machine-specific code to
-setup the stack so that arbitrary frames can be accessed. For example,
-on the SPARC, we must flush all of the register windows to the stack
-before we can access arbitrary stack frames. You will seldom need to
-define this macro. The default is to do nothing.
-@end defmac
-
-@hook TARGET_BUILTIN_SETJMP_FRAME_VALUE
-
-@defmac FRAME_ADDR_RTX (@var{frameaddr})
-A C expression whose value is RTL representing the value of the frame
-address for the current frame. @var{frameaddr} is the frame pointer
-of the current frame. This is used for __builtin_frame_address.
-You need only define this macro if the frame address is not the same
-as the frame pointer. Most machines do not need to define it.
-@end defmac
-
-@defmac RETURN_ADDR_RTX (@var{count}, @var{frameaddr})
-A C expression whose value is RTL representing the value of the return
-address for the frame @var{count} steps up from the current frame, after
-the prologue. @var{frameaddr} is the frame pointer of the @var{count}
-frame, or the frame pointer of the @var{count} @minus{} 1 frame if
-@code{RETURN_ADDR_IN_PREVIOUS_FRAME} is nonzero.
-
-The value of the expression must always be the correct address when
-@var{count} is zero, but may be @code{NULL_RTX} if there is no way to
-determine the return address of other frames.
-@end defmac
-
-@defmac RETURN_ADDR_IN_PREVIOUS_FRAME
-Define this macro to nonzero value if the return address of a particular
-stack frame is accessed from the frame pointer of the previous stack
-frame. The zero default for this macro is suitable for most ports.
-@end defmac
-
-@defmac INCOMING_RETURN_ADDR_RTX
-A C expression whose value is RTL representing the location of the
-incoming return address at the beginning of any function, before the
-prologue. This RTL is either a @code{REG}, indicating that the return
-value is saved in @samp{REG}, or a @code{MEM} representing a location in
-the stack.
-
-You only need to define this macro if you want to support call frame
-debugging information like that provided by DWARF 2.
-
-If this RTL is a @code{REG}, you should also define
-@code{DWARF_FRAME_RETURN_COLUMN} to @code{DWARF_FRAME_REGNUM (REGNO)}.
-@end defmac
-
-@defmac DWARF_ALT_FRAME_RETURN_COLUMN
-A C expression whose value is an integer giving a DWARF 2 column
-number that may be used as an alternative return column. The column
-must not correspond to any gcc hard register (that is, it must not
-be in the range of @code{DWARF_FRAME_REGNUM}).
-
-This macro can be useful if @code{DWARF_FRAME_RETURN_COLUMN} is set to a
-general register, but an alternative column needs to be used for signal
-frames. Some targets have also used different frame return columns
-over time.
-@end defmac
-
-@defmac DWARF_ZERO_REG
-A C expression whose value is an integer giving a DWARF 2 register
-number that is considered to always have the value zero. This should
-only be defined if the target has an architected zero register, and
-someone decided it was a good idea to use that register number to
-terminate the stack backtrace. New ports should avoid this.
-@end defmac
-
-@hook TARGET_DWARF_HANDLE_FRAME_UNSPEC
-
-@hook TARGET_DWARF_POLY_INDETERMINATE_VALUE
-
-@defmac INCOMING_FRAME_SP_OFFSET
-A C expression whose value is an integer giving the offset, in bytes,
-from the value of the stack pointer register to the top of the stack
-frame at the beginning of any function, before the prologue. The top of
-the frame is defined to be the value of the stack pointer in the
-previous frame, just before the call instruction.
-
-You only need to define this macro if you want to support call frame
-debugging information like that provided by DWARF 2.
-@end defmac
-
-@defmac DEFAULT_INCOMING_FRAME_SP_OFFSET
-Like @code{INCOMING_FRAME_SP_OFFSET}, but must be the same for all
-functions of the same ABI, and when using GAS @code{.cfi_*} directives
-must also agree with the default CFI GAS emits. Define this macro
-only if @code{INCOMING_FRAME_SP_OFFSET} can have different values
-between different functions of the same ABI or when
-@code{INCOMING_FRAME_SP_OFFSET} does not agree with GAS default CFI.
-@end defmac
-
-@defmac ARG_POINTER_CFA_OFFSET (@var{fundecl})
-A C expression whose value is an integer giving the offset, in bytes,
-from the argument pointer to the canonical frame address (cfa). The
-final value should coincide with that calculated by
-@code{INCOMING_FRAME_SP_OFFSET}. Which is unfortunately not usable
-during virtual register instantiation.
-
-The default value for this macro is
-@code{FIRST_PARM_OFFSET (fundecl) + crtl->args.pretend_args_size},
-which is correct for most machines; in general, the arguments are found
-immediately before the stack frame. Note that this is not the case on
-some targets that save registers into the caller's frame, such as SPARC
-and rs6000, and so such targets need to define this macro.
-
-You only need to define this macro if the default is incorrect, and you
-want to support call frame debugging information like that provided by
-DWARF 2.
-@end defmac
-
-@defmac FRAME_POINTER_CFA_OFFSET (@var{fundecl})
-If defined, a C expression whose value is an integer giving the offset
-in bytes from the frame pointer to the canonical frame address (cfa).
-The final value should coincide with that calculated by
-@code{INCOMING_FRAME_SP_OFFSET}.
-
-Normally the CFA is calculated as an offset from the argument pointer,
-via @code{ARG_POINTER_CFA_OFFSET}, but if the argument pointer is
-variable due to the ABI, this may not be possible. If this macro is
-defined, it implies that the virtual register instantiation should be
-based on the frame pointer instead of the argument pointer. Only one
-of @code{FRAME_POINTER_CFA_OFFSET} and @code{ARG_POINTER_CFA_OFFSET}
-should be defined.
-@end defmac
-
-@defmac CFA_FRAME_BASE_OFFSET (@var{fundecl})
-If defined, a C expression whose value is an integer giving the offset
-in bytes from the canonical frame address (cfa) to the frame base used
-in DWARF 2 debug information. The default is zero. A different value
-may reduce the size of debug information on some ports.
-@end defmac
-
-@node Exception Handling
-@subsection Exception Handling Support
-@cindex exception handling
-
-@defmac EH_RETURN_DATA_REGNO (@var{N})
-A C expression whose value is the @var{N}th register number used for
-data by exception handlers, or @code{INVALID_REGNUM} if fewer than
-@var{N} registers are usable.
-
-The exception handling library routines communicate with the exception
-handlers via a set of agreed upon registers. Ideally these registers
-should be call-clobbered; it is possible to use call-saved registers,
-but may negatively impact code size. The target must support at least
-2 data registers, but should define 4 if there are enough free registers.
-
-You must define this macro if you want to support call frame exception
-handling like that provided by DWARF 2.
-@end defmac
-
-@defmac EH_RETURN_STACKADJ_RTX
-A C expression whose value is RTL representing a location in which
-to store a stack adjustment to be applied before function return.
-This is used to unwind the stack to an exception handler's call frame.
-It will be assigned zero on code paths that return normally.
-
-Typically this is a call-clobbered hard register that is otherwise
-untouched by the epilogue, but could also be a stack slot.
-
-Do not define this macro if the stack pointer is saved and restored
-by the regular prolog and epilog code in the call frame itself; in
-this case, the exception handling library routines will update the
-stack location to be restored in place. Otherwise, you must define
-this macro if you want to support call frame exception handling like
-that provided by DWARF 2.
-@end defmac
-
-@defmac EH_RETURN_HANDLER_RTX
-A C expression whose value is RTL representing a location in which
-to store the address of an exception handler to which we should
-return. It will not be assigned on code paths that return normally.
-
-Typically this is the location in the call frame at which the normal
-return address is stored. For targets that return by popping an
-address off the stack, this might be a memory address just below
-the @emph{target} call frame rather than inside the current call
-frame. If defined, @code{EH_RETURN_STACKADJ_RTX} will have already
-been assigned, so it may be used to calculate the location of the
-target call frame.
-
-Some targets have more complex requirements than storing to an
-address calculable during initial code generation. In that case
-the @code{eh_return} instruction pattern should be used instead.
-
-If you want to support call frame exception handling, you must
-define either this macro or the @code{eh_return} instruction pattern.
-@end defmac
-
-@defmac RETURN_ADDR_OFFSET
-If defined, an integer-valued C expression for which rtl will be generated
-to add it to the exception handler address before it is searched in the
-exception handling tables, and to subtract it again from the address before
-using it to return to the exception handler.
-@end defmac
-
-@defmac ASM_PREFERRED_EH_DATA_FORMAT (@var{code}, @var{global})
-This macro chooses the encoding of pointers embedded in the exception
-handling sections. If at all possible, this should be defined such
-that the exception handling section will not require dynamic relocations,
-and so may be read-only.
-
-@var{code} is 0 for data, 1 for code labels, 2 for function pointers.
-@var{global} is true if the symbol may be affected by dynamic relocations.
-The macro should return a combination of the @code{DW_EH_PE_*} defines
-as found in @file{dwarf2.h}.
-
-If this macro is not defined, pointers will not be encoded but
-represented directly.
-@end defmac
-
-@defmac ASM_MAYBE_OUTPUT_ENCODED_ADDR_RTX (@var{file}, @var{encoding}, @var{size}, @var{addr}, @var{done})
-This macro allows the target to emit whatever special magic is required
-to represent the encoding chosen by @code{ASM_PREFERRED_EH_DATA_FORMAT}.
-Generic code takes care of pc-relative and indirect encodings; this must
-be defined if the target uses text-relative or data-relative encodings.
-
-This is a C statement that branches to @var{done} if the format was
-handled. @var{encoding} is the format chosen, @var{size} is the number
-of bytes that the format occupies, @var{addr} is the @code{SYMBOL_REF}
-to be emitted.
-@end defmac
-
-@defmac MD_FALLBACK_FRAME_STATE_FOR (@var{context}, @var{fs})
-This macro allows the target to add CPU and operating system specific
-code to the call-frame unwinder for use when there is no unwind data
-available. The most common reason to implement this macro is to unwind
-through signal frames.
-
-This macro is called from @code{uw_frame_state_for} in
-@file{unwind-dw2.c}, @file{unwind-dw2-xtensa.c} and
-@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
-@var{fs} is an @code{_Unwind_FrameState}. Examine @code{context->ra}
-for the address of the code being executed and @code{context->cfa} for
-the stack pointer value. If the frame can be decoded, the register
-save addresses should be updated in @var{fs} and the macro should
-evaluate to @code{_URC_NO_REASON}. If the frame cannot be decoded,
-the macro should evaluate to @code{_URC_END_OF_STACK}.
-
-For proper signal handling in Java this macro is accompanied by
-@code{MAKE_THROW_FRAME}, defined in @file{libjava/include/*-signal.h} headers.
-@end defmac
-
-@defmac MD_HANDLE_UNWABI (@var{context}, @var{fs})
-This macro allows the target to add operating system specific code to the
-call-frame unwinder to handle the IA-64 @code{.unwabi} unwinding directive,
-usually used for signal or interrupt frames.
-
-This macro is called from @code{uw_update_context} in libgcc's
-@file{unwind-ia64.c}. @var{context} is an @code{_Unwind_Context};
-@var{fs} is an @code{_Unwind_FrameState}. Examine @code{fs->unwabi}
-for the abi and context in the @code{.unwabi} directive. If the
-@code{.unwabi} directive can be handled, the register save addresses should
-be updated in @var{fs}.
-@end defmac
-
-@defmac TARGET_USES_WEAK_UNWIND_INFO
-A C expression that evaluates to true if the target requires unwind
-info to be given comdat linkage. Define it to be @code{1} if comdat
-linkage is necessary. The default is @code{0}.
-@end defmac
-
-@node Stack Checking
-@subsection Specifying How Stack Checking is Done
-
-GCC will check that stack references are within the boundaries of the
-stack, if the option @option{-fstack-check} is specified, in one of
-three ways:
-
-@enumerate
-@item
-If the value of the @code{STACK_CHECK_BUILTIN} macro is nonzero, GCC
-will assume that you have arranged for full stack checking to be done
-at appropriate places in the configuration files. GCC will not do
-other special processing.
-
-@item
-If @code{STACK_CHECK_BUILTIN} is zero and the value of the
-@code{STACK_CHECK_STATIC_BUILTIN} macro is nonzero, GCC will assume
-that you have arranged for static stack checking (checking of the
-static stack frame of functions) to be done at appropriate places
-in the configuration files. GCC will only emit code to do dynamic
-stack checking (checking on dynamic stack allocations) using the third
-approach below.
-
-@item
-If neither of the above are true, GCC will generate code to periodically
-``probe'' the stack pointer using the values of the macros defined below.
-@end enumerate
-
-If neither STACK_CHECK_BUILTIN nor STACK_CHECK_STATIC_BUILTIN is defined,
-GCC will change its allocation strategy for large objects if the option
-@option{-fstack-check} is specified: they will always be allocated
-dynamically if their size exceeds @code{STACK_CHECK_MAX_VAR_SIZE} bytes.
-
-@defmac STACK_CHECK_BUILTIN
-A nonzero value if stack checking is done by the configuration files in a
-machine-dependent manner. You should define this macro if stack checking
-is required by the ABI of your machine or if you would like to do stack
-checking in some more efficient way than the generic approach. The default
-value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_STATIC_BUILTIN
-A nonzero value if static stack checking is done by the configuration files
-in a machine-dependent manner. You should define this macro if you would
-like to do static stack checking in some more efficient way than the generic
-approach. The default value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_PROBE_INTERVAL_EXP
-An integer specifying the interval at which GCC must generate stack probe
-instructions, defined as 2 raised to this integer. You will normally
-define this macro so that the interval be no larger than the size of
-the ``guard pages'' at the end of a stack area. The default value
-of 12 (4096-byte interval) is suitable for most systems.
-@end defmac
-
-@defmac STACK_CHECK_MOVING_SP
-An integer which is nonzero if GCC should move the stack pointer page by page
-when doing probes. This can be necessary on systems where the stack pointer
-contains the bottom address of the memory area accessible to the executing
-thread at any point in time. In this situation an alternate signal stack
-is required in order to be able to recover from a stack overflow. The
-default value of this macro is zero.
-@end defmac
-
-@defmac STACK_CHECK_PROTECT
-The number of bytes of stack needed to recover from a stack overflow, for
-languages where such a recovery is supported. The default value of 4KB/8KB
-with the @code{setjmp}/@code{longjmp}-based exception handling mechanism and
-8KB/12KB with other exception handling mechanisms should be adequate for most
-architectures and operating systems.
-@end defmac
-
-The following macros are relevant only if neither STACK_CHECK_BUILTIN
-nor STACK_CHECK_STATIC_BUILTIN is defined; you can omit them altogether
-in the opposite case.
-
-@defmac STACK_CHECK_MAX_FRAME_SIZE
-The maximum size of a stack frame, in bytes. GCC will generate probe
-instructions in non-leaf functions to ensure at least this many bytes of
-stack are available. If a stack frame is larger than this size, stack
-checking will not be reliable and GCC will issue a warning. The
-default is chosen so that GCC only generates one instruction on most
-systems. You should normally not change the default value of this macro.
-@end defmac
-
-@defmac STACK_CHECK_FIXED_FRAME_SIZE
-GCC uses this value to generate the above warning message. It
-represents the amount of fixed frame used by a function, not including
-space for any callee-saved registers, temporaries and user variables.
-You need only specify an upper bound for this amount and will normally
-use the default of four words.
-@end defmac
-
-@defmac STACK_CHECK_MAX_VAR_SIZE
-The maximum size, in bytes, of an object that GCC will place in the
-fixed area of the stack frame when the user specifies
-@option{-fstack-check}.
-GCC computed the default from the values of the above macros and you will
-normally not need to override that default.
-@end defmac
-
-@hook TARGET_STACK_CLASH_PROTECTION_ALLOCA_PROBE_RANGE
-
-@need 2000
-@node Frame Registers
-@subsection Registers That Address the Stack Frame
-
-@c prevent bad page break with this line
-This discusses registers that address the stack frame.
-
-@defmac STACK_POINTER_REGNUM
-The register number of the stack pointer register, which must also be a
-fixed register according to @code{FIXED_REGISTERS}. On most machines,
-the hardware determines which register this is.
-@end defmac
-
-@defmac FRAME_POINTER_REGNUM
-The register number of the frame pointer register, which is used to
-access automatic variables in the stack frame. On some machines, the
-hardware determines which register this is. On other machines, you can
-choose any register you wish for this purpose.
-@end defmac
-
-@defmac HARD_FRAME_POINTER_REGNUM
-On some machines the offset between the frame pointer and starting
-offset of the automatic variables is not known until after register
-allocation has been done (for example, because the saved registers are
-between these two locations). On those machines, define
-@code{FRAME_POINTER_REGNUM} the number of a special, fixed register to
-be used internally until the offset is known, and define
-@code{HARD_FRAME_POINTER_REGNUM} to be the actual hard register number
-used for the frame pointer.
-
-You should define this macro only in the very rare circumstances when it
-is not possible to calculate the offset between the frame pointer and
-the automatic variables until after register allocation has been
-completed. When this macro is defined, you must also indicate in your
-definition of @code{ELIMINABLE_REGS} how to eliminate
-@code{FRAME_POINTER_REGNUM} into either @code{HARD_FRAME_POINTER_REGNUM}
-or @code{STACK_POINTER_REGNUM}.
-
-Do not define this macro if it would be the same as
-@code{FRAME_POINTER_REGNUM}.
-@end defmac
-
-@defmac ARG_POINTER_REGNUM
-The register number of the arg pointer register, which is used to access
-the function's argument list. On some machines, this is the same as the
-frame pointer register. On some machines, the hardware determines which
-register this is. On other machines, you can choose any register you
-wish for this purpose. If this is not the same register as the frame
-pointer register, then you must mark it as a fixed register according to
-@code{FIXED_REGISTERS}, or arrange to be able to eliminate it
-(@pxref{Elimination}).
-@end defmac
-
-@defmac HARD_FRAME_POINTER_IS_FRAME_POINTER
-Define this to a preprocessor constant that is nonzero if
-@code{hard_frame_pointer_rtx} and @code{frame_pointer_rtx} should be
-the same. The default definition is @samp{(HARD_FRAME_POINTER_REGNUM
-== FRAME_POINTER_REGNUM)}; you only need to define this macro if that
-definition is not suitable for use in preprocessor conditionals.
-@end defmac
-
-@defmac HARD_FRAME_POINTER_IS_ARG_POINTER
-Define this to a preprocessor constant that is nonzero if
-@code{hard_frame_pointer_rtx} and @code{arg_pointer_rtx} should be the
-same. The default definition is @samp{(HARD_FRAME_POINTER_REGNUM ==
-ARG_POINTER_REGNUM)}; you only need to define this macro if that
-definition is not suitable for use in preprocessor conditionals.
-@end defmac
-
-@defmac RETURN_ADDRESS_POINTER_REGNUM
-The register number of the return address pointer register, which is used to
-access the current function's return address from the stack. On some
-machines, the return address is not at a fixed offset from the frame
-pointer or stack pointer or argument pointer. This register can be defined
-to point to the return address on the stack, and then be converted by
-@code{ELIMINABLE_REGS} into either the frame pointer or stack pointer.
-
-Do not define this macro unless there is no other way to get the return
-address from the stack.
-@end defmac
-
-@defmac STATIC_CHAIN_REGNUM
-@defmacx STATIC_CHAIN_INCOMING_REGNUM
-Register numbers used for passing a function's static chain pointer. If
-register windows are used, the register number as seen by the called
-function is @code{STATIC_CHAIN_INCOMING_REGNUM}, while the register
-number as seen by the calling function is @code{STATIC_CHAIN_REGNUM}. If
-these registers are the same, @code{STATIC_CHAIN_INCOMING_REGNUM} need
-not be defined.
-
-The static chain register need not be a fixed register.
-
-If the static chain is passed in memory, these macros should not be
-defined; instead, the @code{TARGET_STATIC_CHAIN} hook should be used.
-@end defmac
-
-@hook TARGET_STATIC_CHAIN
-
-@defmac DWARF_FRAME_REGISTERS
-This macro specifies the maximum number of hard registers that can be
-saved in a call frame. This is used to size data structures used in
-DWARF2 exception handling.
-
-Prior to GCC 3.0, this macro was needed in order to establish a stable
-exception handling ABI in the face of adding new hard registers for ISA
-extensions. In GCC 3.0 and later, the EH ABI is insulated from changes
-in the number of hard registers. Nevertheless, this macro can still be
-used to reduce the runtime memory requirements of the exception handling
-routines, which can be substantial if the ISA contains a lot of
-registers that are not call-saved.
-
-If this macro is not defined, it defaults to
-@code{FIRST_PSEUDO_REGISTER}.
-@end defmac
-
-@defmac PRE_GCC3_DWARF_FRAME_REGISTERS
-
-This macro is similar to @code{DWARF_FRAME_REGISTERS}, but is provided
-for backward compatibility in pre GCC 3.0 compiled code.
-
-If this macro is not defined, it defaults to
-@code{DWARF_FRAME_REGISTERS}.
-@end defmac
-
-@defmac DWARF_REG_TO_UNWIND_COLUMN (@var{regno})
-
-Define this macro if the target's representation for dwarf registers
-is different than the internal representation for unwind column.
-Given a dwarf register, this macro should return the internal unwind
-column number to use instead.
-@end defmac
-
-@defmac DWARF_FRAME_REGNUM (@var{regno})
-
-Define this macro if the target's representation for dwarf registers
-used in .eh_frame or .debug_frame is different from that used in other
-debug info sections. Given a GCC hard register number, this macro
-should return the .eh_frame register number. The default is
-@code{DBX_REGISTER_NUMBER (@var{regno})}.
-
-@end defmac
-
-@defmac DWARF2_FRAME_REG_OUT (@var{regno}, @var{for_eh})
-
-Define this macro to map register numbers held in the call frame info
-that GCC has collected using @code{DWARF_FRAME_REGNUM} to those that
-should be output in .debug_frame (@code{@var{for_eh}} is zero) and
-.eh_frame (@code{@var{for_eh}} is nonzero). The default is to
-return @code{@var{regno}}.
-
-@end defmac
-
-@defmac REG_VALUE_IN_UNWIND_CONTEXT
-
-Define this macro if the target stores register values as
-@code{_Unwind_Word} type in unwind context. It should be defined if
-target register size is larger than the size of @code{void *}. The
-default is to store register values as @code{void *} type.
-
-@end defmac
-
-@defmac ASSUME_EXTENDED_UNWIND_CONTEXT
-
-Define this macro to be 1 if the target always uses extended unwind
-context with version, args_size and by_value fields. If it is undefined,
-it will be defined to 1 when @code{REG_VALUE_IN_UNWIND_CONTEXT} is
-defined and 0 otherwise.
-
-@end defmac
-
-@defmac DWARF_LAZY_REGISTER_VALUE (@var{regno}, @var{value})
-Define this macro if the target has pseudo DWARF registers whose
-values need to be computed lazily on demand by the unwinder (such as when
-referenced in a CFA expression). The macro returns true if @var{regno}
-is such a register and stores its value in @samp{*@var{value}} if so.
-@end defmac
-
-@node Elimination
-@subsection Eliminating Frame Pointer and Arg Pointer
-
-@c prevent bad page break with this line
-This is about eliminating the frame pointer and arg pointer.
-
-@hook TARGET_FRAME_POINTER_REQUIRED
-
-@defmac ELIMINABLE_REGS
-This macro specifies a table of register pairs used to eliminate
-unneeded registers that point into the stack frame.
-
-The definition of this macro is a list of structure initializations, each
-of which specifies an original and replacement register.
-
-On some machines, the position of the argument pointer is not known until
-the compilation is completed. In such a case, a separate hard register
-must be used for the argument pointer. This register can be eliminated by
-replacing it with either the frame pointer or the argument pointer,
-depending on whether or not the frame pointer has been eliminated.
-
-In this case, you might specify:
-@smallexample
-#define ELIMINABLE_REGS \
-@{@{ARG_POINTER_REGNUM, STACK_POINTER_REGNUM@}, \
- @{ARG_POINTER_REGNUM, FRAME_POINTER_REGNUM@}, \
- @{FRAME_POINTER_REGNUM, STACK_POINTER_REGNUM@}@}
-@end smallexample
-
-Note that the elimination of the argument pointer with the stack pointer is
-specified first since that is the preferred elimination.
-@end defmac
-
-@hook TARGET_CAN_ELIMINATE
-
-@defmac INITIAL_ELIMINATION_OFFSET (@var{from-reg}, @var{to-reg}, @var{offset-var})
-This macro returns the initial difference between the specified pair
-of registers. The value would be computed from information
-such as the result of @code{get_frame_size ()} and the tables of
-registers @code{df_regs_ever_live_p} and @code{call_used_regs}.
-@end defmac
-
-@hook TARGET_COMPUTE_FRAME_LAYOUT
-
-@node Stack Arguments
-@subsection Passing Function Arguments on the Stack
-@cindex arguments on stack
-@cindex stack arguments
-
-The macros in this section control how arguments are passed
-on the stack. See the following section for other macros that
-control passing certain arguments in registers.
-
-@hook TARGET_PROMOTE_PROTOTYPES
-
-@hook TARGET_PUSH_ARGUMENT
-
-@defmac PUSH_ARGS_REVERSED
-A C expression. If nonzero, function arguments will be evaluated from
-last to first, rather than from first to last. If this macro is not
-defined, it defaults to @code{PUSH_ARGS} on targets where the stack
-and args grow in opposite directions, and 0 otherwise.
-@end defmac
-
-@defmac PUSH_ROUNDING (@var{npushed})
-A C expression that is the number of bytes actually pushed onto the
-stack when an instruction attempts to push @var{npushed} bytes.
-
-On some machines, the definition
-
-@smallexample
-#define PUSH_ROUNDING(BYTES) (BYTES)
-@end smallexample
-
-@noindent
-will suffice. But on other machines, instructions that appear
-to push one byte actually push two bytes in an attempt to maintain
-alignment. Then the definition should be
-
-@smallexample
-#define PUSH_ROUNDING(BYTES) (((BYTES) + 1) & ~1)
-@end smallexample
-
-If the value of this macro has a type, it should be an unsigned type.
-@end defmac
-
-@findex outgoing_args_size
-@findex crtl->outgoing_args_size
-@defmac ACCUMULATE_OUTGOING_ARGS
-A C expression. If nonzero, the maximum amount of space required for outgoing arguments
-will be computed and placed into
-@code{crtl->outgoing_args_size}. No space will be pushed
-onto the stack for each call; instead, the function prologue should
-increase the stack frame size by this amount.
-
-Setting both @code{PUSH_ARGS} and @code{ACCUMULATE_OUTGOING_ARGS}
-is not proper.
-@end defmac
-
-@defmac REG_PARM_STACK_SPACE (@var{fndecl})
-Define this macro if functions should assume that stack space has been
-allocated for arguments even when their values are passed in
-registers.
-
-The value of this macro is the size, in bytes, of the area reserved for
-arguments passed in registers for the function represented by @var{fndecl},
-which can be zero if GCC is calling a library function.
-The argument @var{fndecl} can be the FUNCTION_DECL, or the type itself
-of the function.
-
-This space can be allocated by the caller, or be a part of the
-machine-dependent stack frame: @code{OUTGOING_REG_PARM_STACK_SPACE} says
-which.
-@end defmac
-@c above is overfull. not sure what to do. --mew 5feb93 did
-@c something, not sure if it looks good. --mew 10feb93
-
-@defmac INCOMING_REG_PARM_STACK_SPACE (@var{fndecl})
-Like @code{REG_PARM_STACK_SPACE}, but for incoming register arguments.
-Define this macro if space guaranteed when compiling a function body
-is different to space required when making a call, a situation that
-can arise with K&R style function definitions.
-@end defmac
-
-@defmac OUTGOING_REG_PARM_STACK_SPACE (@var{fntype})
-Define this to a nonzero value if it is the responsibility of the
-caller to allocate the area reserved for arguments passed in registers
-when calling a function of @var{fntype}. @var{fntype} may be NULL
-if the function called is a library function.
-
-If @code{ACCUMULATE_OUTGOING_ARGS} is defined, this macro controls
-whether the space for these arguments counts in the value of
-@code{crtl->outgoing_args_size}.
-@end defmac
-
-@defmac STACK_PARMS_IN_REG_PARM_AREA
-Define this macro if @code{REG_PARM_STACK_SPACE} is defined, but the
-stack parameters don't skip the area specified by it.
-@c i changed this, makes more sens and it should have taken care of the
-@c overfull.. not as specific, tho. --mew 5feb93
-
-Normally, when a parameter is not passed in registers, it is placed on the
-stack beyond the @code{REG_PARM_STACK_SPACE} area. Defining this macro
-suppresses this behavior and causes the parameter to be passed on the
-stack in its natural location.
-@end defmac
-
-@hook TARGET_RETURN_POPS_ARGS
-
-@defmac CALL_POPS_ARGS (@var{cum})
-A C expression that should indicate the number of bytes a call sequence
-pops off the stack. It is added to the value of @code{RETURN_POPS_ARGS}
-when compiling a function call.
-
-@var{cum} is the variable in which all arguments to the called function
-have been accumulated.
-
-On certain architectures, such as the SH5, a call trampoline is used
-that pops certain registers off the stack, depending on the arguments
-that have been passed to the function. Since this is a property of the
-call site, not of the called function, @code{RETURN_POPS_ARGS} is not
-appropriate.
-@end defmac
-
-@node Register Arguments
-@subsection Passing Arguments in Registers
-@cindex arguments in registers
-@cindex registers arguments
-
-This section describes the macros which let you control how various
-types of arguments are passed in registers or how they are arranged in
-the stack.
-
-@hook TARGET_FUNCTION_ARG
-
-@hook TARGET_MUST_PASS_IN_STACK
-
-@hook TARGET_FUNCTION_INCOMING_ARG
-
-@hook TARGET_USE_PSEUDO_PIC_REG
-
-@hook TARGET_INIT_PIC_REG
-
-@hook TARGET_ARG_PARTIAL_BYTES
-
-@hook TARGET_PASS_BY_REFERENCE
-
-@hook TARGET_CALLEE_COPIES
-
-@defmac CUMULATIVE_ARGS
-A C type for declaring a variable that is used as the first argument
-of @code{TARGET_FUNCTION_ARG} and other related values. For some
-target machines, the type @code{int} suffices and can hold the number
-of bytes of argument so far.
-
-There is no need to record in @code{CUMULATIVE_ARGS} anything about the
-arguments that have been passed on the stack. The compiler has other
-variables to keep track of that. For target machines on which all
-arguments are passed on the stack, there is no need to store anything in
-@code{CUMULATIVE_ARGS}; however, the data structure must exist and
-should not be empty, so use @code{int}.
-@end defmac
-
-@defmac OVERRIDE_ABI_FORMAT (@var{fndecl})
-If defined, this macro is called before generating any code for a
-function, but after the @var{cfun} descriptor for the function has been
-created. The back end may use this macro to update @var{cfun} to
-reflect an ABI other than that which would normally be used by default.
-If the compiler is generating code for a compiler-generated function,
-@var{fndecl} may be @code{NULL}.
-@end defmac
-
-@defmac INIT_CUMULATIVE_ARGS (@var{cum}, @var{fntype}, @var{libname}, @var{fndecl}, @var{n_named_args})
-A C statement (sans semicolon) for initializing the variable
-@var{cum} for the state at the beginning of the argument list. The
-variable has type @code{CUMULATIVE_ARGS}. The value of @var{fntype}
-is the tree node for the data type of the function which will receive
-the args, or 0 if the args are to a compiler support library function.
-For direct calls that are not libcalls, @var{fndecl} contain the
-declaration node of the function. @var{fndecl} is also set when
-@code{INIT_CUMULATIVE_ARGS} is used to find arguments for the function
-being compiled. @var{n_named_args} is set to the number of named
-arguments, including a structure return address if it is passed as a
-parameter, when making a call. When processing incoming arguments,
-@var{n_named_args} is set to @minus{}1.
-
-When processing a call to a compiler support library function,
-@var{libname} identifies which one. It is a @code{symbol_ref} rtx which
-contains the name of the function, as a string. @var{libname} is 0 when
-an ordinary C function call is being processed. Thus, each time this
-macro is called, either @var{libname} or @var{fntype} is nonzero, but
-never both of them at once.
-@end defmac
-
-@defmac INIT_CUMULATIVE_LIBCALL_ARGS (@var{cum}, @var{mode}, @var{libname})
-Like @code{INIT_CUMULATIVE_ARGS} but only used for outgoing libcalls,
-it gets a @code{MODE} argument instead of @var{fntype}, that would be
-@code{NULL}. @var{indirect} would always be zero, too. If this macro
-is not defined, @code{INIT_CUMULATIVE_ARGS (cum, NULL_RTX, libname,
-0)} is used instead.
-@end defmac
-
-@defmac INIT_CUMULATIVE_INCOMING_ARGS (@var{cum}, @var{fntype}, @var{libname})
-Like @code{INIT_CUMULATIVE_ARGS} but overrides it for the purposes of
-finding the arguments for the function being compiled. If this macro is
-undefined, @code{INIT_CUMULATIVE_ARGS} is used instead.
-
-The value passed for @var{libname} is always 0, since library routines
-with special calling conventions are never compiled with GCC@. The
-argument @var{libname} exists for symmetry with
-@code{INIT_CUMULATIVE_ARGS}.
-@c could use "this macro" in place of @code{INIT_CUMULATIVE_ARGS}, maybe.
-@c --mew 5feb93 i switched the order of the sentences. --mew 10feb93
-@end defmac
-
-@hook TARGET_FUNCTION_ARG_ADVANCE
-
-@hook TARGET_FUNCTION_ARG_OFFSET
-
-@hook TARGET_FUNCTION_ARG_PADDING
-
-@defmac PAD_VARARGS_DOWN
-If defined, a C expression which determines whether the default
-implementation of va_arg will attempt to pad down before reading the
-next argument, if that argument is smaller than its aligned space as
-controlled by @code{PARM_BOUNDARY}. If this macro is not defined, all such
-arguments are padded down if @code{BYTES_BIG_ENDIAN} is true.
-@end defmac
-
-@defmac BLOCK_REG_PADDING (@var{mode}, @var{type}, @var{first})
-Specify padding for the last element of a block move between registers and
-memory. @var{first} is nonzero if this is the only element. Defining this
-macro allows better control of register function parameters on big-endian
-machines, without using @code{PARALLEL} rtl. In particular,
-@code{MUST_PASS_IN_STACK} need not test padding and mode of types in
-registers, as there is no longer a "wrong" part of a register; For example,
-a three byte aggregate may be passed in the high part of a register if so
-required.
-@end defmac
-
-@hook TARGET_FUNCTION_ARG_BOUNDARY
-
-@hook TARGET_FUNCTION_ARG_ROUND_BOUNDARY
-
-@defmac FUNCTION_ARG_REGNO_P (@var{regno})
-A C expression that is nonzero if @var{regno} is the number of a hard
-register in which function arguments are sometimes passed. This does
-@emph{not} include implicit arguments such as the static chain and
-the structure-value address. On many machines, no registers can be
-used for this purpose since all function arguments are pushed on the
-stack.
-@end defmac
-
-@hook TARGET_SPLIT_COMPLEX_ARG
-
-@hook TARGET_BUILD_BUILTIN_VA_LIST
-
-@hook TARGET_ENUM_VA_LIST_P
-
-@hook TARGET_FN_ABI_VA_LIST
-
-@hook TARGET_CANONICAL_VA_LIST_TYPE
-
-@hook TARGET_GIMPLIFY_VA_ARG_EXPR
-
-@hook TARGET_VALID_POINTER_MODE
-
-@hook TARGET_REF_MAY_ALIAS_ERRNO
-
-@hook TARGET_TRANSLATE_MODE_ATTRIBUTE
-
-@hook TARGET_SCALAR_MODE_SUPPORTED_P
-
-@hook TARGET_VECTOR_MODE_SUPPORTED_P
-
-@hook TARGET_COMPATIBLE_VECTOR_TYPES_P
-
-@hook TARGET_ARRAY_MODE
-
-@hook TARGET_ARRAY_MODE_SUPPORTED_P
-
-@hook TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P
-
-@hook TARGET_FLOATN_MODE
-
-@hook TARGET_FLOATN_BUILTIN_P
-
-@hook TARGET_SMALL_REGISTER_CLASSES_FOR_MODE_P
-
-@node Scalar Return
-@subsection How Scalar Function Values Are Returned
-@cindex return values in registers
-@cindex values, returned by functions
-@cindex scalars, returned as values
-
-This section discusses the macros that control returning scalars as
-values---values that can fit in registers.
-
-@hook TARGET_FUNCTION_VALUE
-
-@defmac FUNCTION_VALUE (@var{valtype}, @var{func})
-This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE} for
-a new target instead.
-@end defmac
-
-@defmac LIBCALL_VALUE (@var{mode})
-A C expression to create an RTX representing the place where a library
-function returns a value of mode @var{mode}.
-
-Note that ``library function'' in this context means a compiler
-support routine, used to perform arithmetic, whose name is known
-specially by the compiler and was not mentioned in the C code being
-compiled.
-@end defmac
-
-@hook TARGET_LIBCALL_VALUE
-
-@defmac FUNCTION_VALUE_REGNO_P (@var{regno})
-A C expression that is nonzero if @var{regno} is the number of a hard
-register in which the values of called function may come back.
-
-A register whose use for returning values is limited to serving as the
-second of a pair (for a value of type @code{double}, say) need not be
-recognized by this macro. So for most machines, this definition
-suffices:
-
-@smallexample
-#define FUNCTION_VALUE_REGNO_P(N) ((N) == 0)
-@end smallexample
-
-If the machine has register windows, so that the caller and the called
-function use different registers for the return value, this macro
-should recognize only the caller's register numbers.
-
-This macro has been deprecated. Use @code{TARGET_FUNCTION_VALUE_REGNO_P}
-for a new target instead.
-@end defmac
-
-@hook TARGET_FUNCTION_VALUE_REGNO_P
-
-@defmac APPLY_RESULT_SIZE
-Define this macro if @samp{untyped_call} and @samp{untyped_return}
-need more space than is implied by @code{FUNCTION_VALUE_REGNO_P} for
-saving and restoring an arbitrary return value.
-@end defmac
-
-@hook TARGET_OMIT_STRUCT_RETURN_REG
-
-@hook TARGET_RETURN_IN_MSB
-
-@node Aggregate Return
-@subsection How Large Values Are Returned
-@cindex aggregates as return values
-@cindex large return values
-@cindex returning aggregate values
-@cindex structure value address
-
-When a function value's mode is @code{BLKmode} (and in some other
-cases), the value is not returned according to
-@code{TARGET_FUNCTION_VALUE} (@pxref{Scalar Return}). Instead, the
-caller passes the address of a block of memory in which the value
-should be stored. This address is called the @dfn{structure value
-address}.
-
-This section describes how to control returning structure values in
-memory.
-
-@hook TARGET_RETURN_IN_MEMORY
-
-@defmac DEFAULT_PCC_STRUCT_RETURN
-Define this macro to be 1 if all structure and union return values must be
-in memory. Since this results in slower code, this should be defined
-only if needed for compatibility with other compilers or with an ABI@.
-If you define this macro to be 0, then the conventions used for structure
-and union return values are decided by the @code{TARGET_RETURN_IN_MEMORY}
-target hook.
-
-If not defined, this defaults to the value 1.
-@end defmac
-
-@hook TARGET_STRUCT_VALUE_RTX
-
-@defmac PCC_STATIC_STRUCT_RETURN
-Define this macro if the usual system convention on the target machine
-for returning structures and unions is for the called function to return
-the address of a static variable containing the value.
-
-Do not define this if the usual system convention is for the caller to
-pass an address to the subroutine.
-
-This macro has effect in @option{-fpcc-struct-return} mode, but it does
-nothing when you use @option{-freg-struct-return} mode.
-@end defmac
-
-@hook TARGET_GET_RAW_RESULT_MODE
-
-@hook TARGET_GET_RAW_ARG_MODE
-
-@hook TARGET_EMPTY_RECORD_P
-
-@hook TARGET_WARN_PARAMETER_PASSING_ABI
-
-@node Caller Saves
-@subsection Caller-Saves Register Allocation
-
-If you enable it, GCC can save registers around function calls. This
-makes it possible to use call-clobbered registers to hold variables that
-must live across calls.
-
-@defmac HARD_REGNO_CALLER_SAVE_MODE (@var{regno}, @var{nregs})
-A C expression specifying which mode is required for saving @var{nregs}
-of a pseudo-register in call-clobbered hard register @var{regno}. If
-@var{regno} is unsuitable for caller save, @code{VOIDmode} should be
-returned. For most machines this macro need not be defined since GCC
-will select the smallest suitable mode.
-@end defmac
-
-@node Function Entry
-@subsection Function Entry and Exit
-@cindex function entry and exit
-@cindex prologue
-@cindex epilogue
-
-This section describes the macros that output function entry
-(@dfn{prologue}) and exit (@dfn{epilogue}) code.
-
-@hook TARGET_ASM_PRINT_PATCHABLE_FUNCTION_ENTRY
-
-@hook TARGET_ASM_FUNCTION_PROLOGUE
-
-@hook TARGET_ASM_FUNCTION_END_PROLOGUE
-
-@hook TARGET_ASM_FUNCTION_BEGIN_EPILOGUE
-
-@hook TARGET_ASM_FUNCTION_EPILOGUE
-
-@itemize @bullet
-@item
-@findex pretend_args_size
-@findex crtl->args.pretend_args_size
-A region of @code{crtl->args.pretend_args_size} bytes of
-uninitialized space just underneath the first argument arriving on the
-stack. (This may not be at the very start of the allocated stack region
-if the calling sequence has pushed anything else since pushing the stack
-arguments. But usually, on such machines, nothing else has been pushed
-yet, because the function prologue itself does all the pushing.) This
-region is used on machines where an argument may be passed partly in
-registers and partly in memory, and, in some cases to support the
-features in @code{<stdarg.h>}.
-
-@item
-An area of memory used to save certain registers used by the function.
-The size of this area, which may also include space for such things as
-the return address and pointers to previous stack frames, is
-machine-specific and usually depends on which registers have been used
-in the function. Machines with register windows often do not require
-a save area.
-
-@item
-A region of at least @var{size} bytes, possibly rounded up to an allocation
-boundary, to contain the local variables of the function. On some machines,
-this region and the save area may occur in the opposite order, with the
-save area closer to the top of the stack.
-
-@item
-@cindex @code{ACCUMULATE_OUTGOING_ARGS} and stack frames
-Optionally, when @code{ACCUMULATE_OUTGOING_ARGS} is defined, a region of
-@code{crtl->outgoing_args_size} bytes to be used for outgoing
-argument lists of the function. @xref{Stack Arguments}.
-@end itemize
-
-@defmac EXIT_IGNORE_STACK
-Define this macro as a C expression that is nonzero if the return
-instruction or the function epilogue ignores the value of the stack
-pointer; in other words, if it is safe to delete an instruction to
-adjust the stack pointer before a return from the function. The
-default is 0.
-
-Note that this macro's value is relevant only for functions for which
-frame pointers are maintained. It is never safe to delete a final
-stack adjustment in a function that has no frame pointer, and the
-compiler knows this regardless of @code{EXIT_IGNORE_STACK}.
-@end defmac
-
-@defmac EPILOGUE_USES (@var{regno})
-Define this macro as a C expression that is nonzero for registers that are
-used by the epilogue or the @samp{return} pattern. The stack and frame
-pointer registers are already assumed to be used as needed.
-@end defmac
-
-@defmac EH_USES (@var{regno})
-Define this macro as a C expression that is nonzero for registers that are
-used by the exception handling mechanism, and so should be considered live
-on entry to an exception edge.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_MI_THUNK
-
-@hook TARGET_ASM_CAN_OUTPUT_MI_THUNK
-
-@node Profiling
-@subsection Generating Code for Profiling
-@cindex profiling, code generation
-
-These macros will help you generate code for profiling.
-
-@defmac FUNCTION_PROFILER (@var{file}, @var{labelno})
-A C statement or compound statement to output to @var{file} some
-assembler code to call the profiling subroutine @code{mcount}.
-
-@findex mcount
-The details of how @code{mcount} expects to be called are determined by
-your operating system environment, not by GCC@. To figure them out,
-compile a small program for profiling using the system's installed C
-compiler and look at the assembler code that results.
-
-Older implementations of @code{mcount} expect the address of a counter
-variable to be loaded into some register. The name of this variable is
-@samp{LP} followed by the number @var{labelno}, so you would generate
-the name using @samp{LP%d} in a @code{fprintf}.
-@end defmac
-
-@defmac PROFILE_HOOK
-A C statement or compound statement to output to @var{file} some assembly
-code to call the profiling subroutine @code{mcount} even the target does
-not support profiling.
-@end defmac
-
-@defmac NO_PROFILE_COUNTERS
-Define this macro to be an expression with a nonzero value if the
-@code{mcount} subroutine on your system does not need a counter variable
-allocated for each function. This is true for almost all modern
-implementations. If you define this macro, you must not use the
-@var{labelno} argument to @code{FUNCTION_PROFILER}.
-@end defmac
-
-@defmac PROFILE_BEFORE_PROLOGUE
-Define this macro if the code for function profiling should come before
-the function prologue. Normally, the profiling code comes after.
-@end defmac
-
-@hook TARGET_KEEP_LEAF_WHEN_PROFILED
-
-@node Tail Calls
-@subsection Permitting tail calls
-@cindex tail calls
-
-@hook TARGET_FUNCTION_OK_FOR_SIBCALL
-
-@hook TARGET_EXTRA_LIVE_ON_ENTRY
-
-@hook TARGET_SET_UP_BY_PROLOGUE
-
-@hook TARGET_WARN_FUNC_RETURN
-
-@node Shrink-wrapping separate components
-@subsection Shrink-wrapping separate components
-@cindex shrink-wrapping separate components
-
-The prologue may perform a variety of target dependent tasks such as
-saving callee-saved registers, saving the return address, aligning the
-stack, creating a stack frame, initializing the PIC register, setting
-up the static chain, etc.
-
-On some targets some of these tasks may be independent of others and
-thus may be shrink-wrapped separately. These independent tasks are
-referred to as components and are handled generically by the target
-independent parts of GCC.
-
-Using the following hooks those prologue or epilogue components can be
-shrink-wrapped separately, so that the initialization (and possibly
-teardown) those components do is not done as frequently on execution
-paths where this would unnecessary.
-
-What exactly those components are is up to the target code; the generic
-code treats them abstractly, as a bit in an @code{sbitmap}. These
-@code{sbitmap}s are allocated by the @code{shrink_wrap.get_separate_components}
-and @code{shrink_wrap.components_for_bb} hooks, and deallocated by the
-generic code.
-
-@hook TARGET_SHRINK_WRAP_GET_SEPARATE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_COMPONENTS_FOR_BB
-
-@hook TARGET_SHRINK_WRAP_DISQUALIFY_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_EMIT_PROLOGUE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_EMIT_EPILOGUE_COMPONENTS
-
-@hook TARGET_SHRINK_WRAP_SET_HANDLED_COMPONENTS
-
-@node Stack Smashing Protection
-@subsection Stack smashing protection
-@cindex stack smashing protection
-
-@hook TARGET_STACK_PROTECT_GUARD
-
-@hook TARGET_STACK_PROTECT_FAIL
-
-@hook TARGET_STACK_PROTECT_RUNTIME_ENABLED_P
-
-@hook TARGET_SUPPORTS_SPLIT_STACK
-
-@hook TARGET_GET_VALID_OPTION_VALUES
-
-@node Miscellaneous Register Hooks
-@subsection Miscellaneous register hooks
-@cindex miscellaneous register hooks
-
-@hook TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS
-
-@node Varargs
-@section Implementing the Varargs Macros
-@cindex varargs implementation
-
-GCC comes with an implementation of @code{<varargs.h>} and
-@code{<stdarg.h>} that work without change on machines that pass arguments
-on the stack. Other machines require their own implementations of
-varargs, and the two machine independent header files must have
-conditionals to include it.
-
-ISO @code{<stdarg.h>} differs from traditional @code{<varargs.h>} mainly in
-the calling convention for @code{va_start}. The traditional
-implementation takes just one argument, which is the variable in which
-to store the argument pointer. The ISO implementation of
-@code{va_start} takes an additional second argument. The user is
-supposed to write the last named argument of the function here.
-
-However, @code{va_start} should not use this argument. The way to find
-the end of the named arguments is with the built-in functions described
-below.
-
-@defmac __builtin_saveregs ()
-Use this built-in function to save the argument registers in memory so
-that the varargs mechanism can access them. Both ISO and traditional
-versions of @code{va_start} must use @code{__builtin_saveregs}, unless
-you use @code{TARGET_SETUP_INCOMING_VARARGS} (see below) instead.
-
-On some machines, @code{__builtin_saveregs} is open-coded under the
-control of the target hook @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. On
-other machines, it calls a routine written in assembler language,
-found in @file{libgcc2.c}.
-
-Code generated for the call to @code{__builtin_saveregs} appears at the
-beginning of the function, as opposed to where the call to
-@code{__builtin_saveregs} is written, regardless of what the code is.
-This is because the registers must be saved before the function starts
-to use them for its own purposes.
-@c i rewrote the first sentence above to fix an overfull hbox. --mew
-@c 10feb93
-@end defmac
-
-@defmac __builtin_next_arg (@var{lastarg})
-This builtin returns the address of the first anonymous stack
-argument, as type @code{void *}. If @code{ARGS_GROW_DOWNWARD}, it
-returns the address of the location above the first anonymous stack
-argument. Use it in @code{va_start} to initialize the pointer for
-fetching arguments from the stack. Also use it in @code{va_start} to
-verify that the second parameter @var{lastarg} is the last named argument
-of the current function.
-@end defmac
-
-@defmac __builtin_classify_type (@var{object})
-Since each machine has its own conventions for which data types are
-passed in which kind of register, your implementation of @code{va_arg}
-has to embody these conventions. The easiest way to categorize the
-specified data type is to use @code{__builtin_classify_type} together
-with @code{sizeof} and @code{__alignof__}.
-
-@code{__builtin_classify_type} ignores the value of @var{object},
-considering only its data type. It returns an integer describing what
-kind of type that is---integer, floating, pointer, structure, and so on.
-
-The file @file{typeclass.h} defines an enumeration that you can use to
-interpret the values of @code{__builtin_classify_type}.
-@end defmac
-
-These machine description macros help implement varargs:
-
-@hook TARGET_EXPAND_BUILTIN_SAVEREGS
-
-@hook TARGET_SETUP_INCOMING_VARARGS
-
-@hook TARGET_STRICT_ARGUMENT_NAMING
-
-@hook TARGET_CALL_ARGS
-
-@hook TARGET_END_CALL_ARGS
-
-@hook TARGET_PRETEND_OUTGOING_VARARGS_NAMED
-
-@node Trampolines
-@section Support for Nested Functions
-@cindex support for nested functions
-@cindex trampolines for nested functions
-@cindex descriptors for nested functions
-@cindex nested functions, support for
-
-Taking the address of a nested function requires special compiler
-handling to ensure that the static chain register is loaded when
-the function is invoked via an indirect call.
-
-GCC has traditionally supported nested functions by creating an
-executable @dfn{trampoline} at run time when the address of a nested
-function is taken. This is a small piece of code which normally
-resides on the stack, in the stack frame of the containing function.
-The trampoline loads the static chain register and then jumps to the
-real address of the nested function.
-
-The use of trampolines requires an executable stack, which is a
-security risk. To avoid this problem, GCC also supports another
-strategy: using descriptors for nested functions. Under this model,
-taking the address of a nested function results in a pointer to a
-non-executable function descriptor object. Initializing the static chain
-from the descriptor is handled at indirect call sites.
-
-On some targets, including HPPA and IA-64, function descriptors may be
-mandated by the ABI or be otherwise handled in a target-specific way
-by the back end in its code generation strategy for indirect calls.
-GCC also provides its own generic descriptor implementation to support the
-@option{-fno-trampolines} option. In this case runtime detection of
-function descriptors at indirect call sites relies on descriptor
-pointers being tagged with a bit that is never set in bare function
-addresses. Since GCC's generic function descriptors are
-not ABI-compliant, this option is typically used only on a
-per-language basis (notably by Ada) or when it can otherwise be
-applied to the whole program.
-
-For languages other than Ada, the @code{-ftrampolines} and
-@code{-fno-trampolines} options currently have no effect, and
-trampolines are always generated on platforms that need them
-for nested functions.
-
-Define the following hook if your backend either implements ABI-specified
-descriptor support, or can use GCC's generic descriptor implementation
-for nested functions.
-
-@hook TARGET_CUSTOM_FUNCTION_DESCRIPTORS
-
-The following macros tell GCC how to generate code to allocate and
-initialize an executable trampoline. You can also use this interface
-if your back end needs to create ABI-specified non-executable descriptors; in
-this case the "trampoline" created is the descriptor containing data only.
-
-The instructions in an executable trampoline must do two things: load
-a constant address into the static chain register, and jump to the real
-address of the nested function. On CISC machines such as the m68k,
-this requires two instructions, a move immediate and a jump. Then the
-two addresses exist in the trampoline as word-long immediate operands.
-On RISC machines, it is often necessary to load each address into a
-register in two parts. Then pieces of each address form separate
-immediate operands.
-
-The code generated to initialize the trampoline must store the variable
-parts---the static chain value and the function address---into the
-immediate operands of the instructions. On a CISC machine, this is
-simply a matter of copying each address to a memory reference at the
-proper offset from the start of the trampoline. On a RISC machine, it
-may be necessary to take out pieces of the address and store them
-separately.
-
-@hook TARGET_ASM_TRAMPOLINE_TEMPLATE
-
-@defmac TRAMPOLINE_SECTION
-Return the section into which the trampoline template is to be placed
-(@pxref{Sections}). The default value is @code{readonly_data_section}.
-@end defmac
-
-@defmac TRAMPOLINE_SIZE
-A C expression for the size in bytes of the trampoline, as an integer.
-@end defmac
-
-@defmac TRAMPOLINE_ALIGNMENT
-Alignment required for trampolines, in bits.
-
-If you don't define this macro, the value of @code{FUNCTION_ALIGNMENT}
-is used for aligning trampolines.
-@end defmac
-
-@hook TARGET_TRAMPOLINE_INIT
-
-@hook TARGET_EMIT_CALL_BUILTIN___CLEAR_CACHE
-
-@hook TARGET_TRAMPOLINE_ADJUST_ADDRESS
-
-Implementing trampolines is difficult on many machines because they have
-separate instruction and data caches. Writing into a stack location
-fails to clear the memory in the instruction cache, so when the program
-jumps to that location, it executes the old contents.
-
-Here are two possible solutions. One is to clear the relevant parts of
-the instruction cache whenever a trampoline is set up. The other is to
-make all trampolines identical, by having them jump to a standard
-subroutine. The former technique makes trampoline execution faster; the
-latter makes initialization faster.
-
-To clear the instruction cache when a trampoline is initialized, define
-the following macro.
-
-@defmac CLEAR_INSN_CACHE (@var{beg}, @var{end})
-If defined, expands to a C expression clearing the @emph{instruction
-cache} in the specified interval. The definition of this macro would
-typically be a series of @code{asm} statements. Both @var{beg} and
-@var{end} are pointer expressions.
-@end defmac
-
-To use a standard subroutine, define the following macro. In addition,
-you must make sure that the instructions in a trampoline fill an entire
-cache line with identical instructions, or else ensure that the
-beginning of the trampoline code is always aligned at the same point in
-its cache line. Look in @file{m68k.h} as a guide.
-
-@defmac TRANSFER_FROM_TRAMPOLINE
-Define this macro if trampolines need a special subroutine to do their
-work. The macro should expand to a series of @code{asm} statements
-which will be compiled with GCC@. They go in a library function named
-@code{__transfer_from_trampoline}.
-
-If you need to avoid executing the ordinary prologue code of a compiled
-C function when you jump to the subroutine, you can do so by placing a
-special label of your own in the assembler code. Use one @code{asm}
-statement to generate an assembler label, and another to make the label
-global. Then trampolines can use that label to jump directly to your
-special assembler code.
-@end defmac
-
-@node Library Calls
-@section Implicit Calls to Library Routines
-@cindex library subroutine names
-@cindex @file{libgcc.a}
-
-@c prevent bad page break with this line
-Here is an explanation of implicit calls to library routines.
-
-@defmac DECLARE_LIBRARY_RENAMES
-This macro, if defined, should expand to a piece of C code that will get
-expanded when compiling functions for libgcc.a. It can be used to
-provide alternate names for GCC's internal library functions if there
-are ABI-mandated names that the compiler should provide.
-@end defmac
-
-@findex set_optab_libfunc
-@findex init_one_libfunc
-@hook TARGET_INIT_LIBFUNCS
-
-@hook TARGET_LIBFUNC_GNU_PREFIX
-
-@defmac FLOAT_LIB_COMPARE_RETURNS_BOOL (@var{mode}, @var{comparison})
-This macro should return @code{true} if the library routine that
-implements the floating point comparison operator @var{comparison} in
-mode @var{mode} will return a boolean, and @var{false} if it will
-return a tristate.
-
-GCC's own floating point libraries return tristates from the
-comparison operators, so the default returns false always. Most ports
-don't need to define this macro.
-@end defmac
-
-@defmac TARGET_LIB_INT_CMP_BIASED
-This macro should evaluate to @code{true} if the integer comparison
-functions (like @code{__cmpdi2}) return 0 to indicate that the first
-operand is smaller than the second, 1 to indicate that they are equal,
-and 2 to indicate that the first operand is greater than the second.
-If this macro evaluates to @code{false} the comparison functions return
-@minus{}1, 0, and 1 instead of 0, 1, and 2. If the target uses the routines
-in @file{libgcc.a}, you do not need to define this macro.
-@end defmac
-
-@defmac TARGET_HAS_NO_HW_DIVIDE
-This macro should be defined if the target has no hardware divide
-instructions. If this macro is defined, GCC will use an algorithm which
-make use of simple logical and arithmetic operations for 64-bit
-division. If the macro is not defined, GCC will use an algorithm which
-make use of a 64-bit by 32-bit divide primitive.
-@end defmac
-
-@cindex @code{EDOM}, implicit usage
-@findex matherr
-@defmac TARGET_EDOM
-The value of @code{EDOM} on the target machine, as a C integer constant
-expression. If you don't define this macro, GCC does not attempt to
-deposit the value of @code{EDOM} into @code{errno} directly. Look in
-@file{/usr/include/errno.h} to find the value of @code{EDOM} on your
-system.
-
-If you do not define @code{TARGET_EDOM}, then compiled code reports
-domain errors by calling the library function and letting it report the
-error. If mathematical functions on your system use @code{matherr} when
-there is an error, then you should leave @code{TARGET_EDOM} undefined so
-that @code{matherr} is used normally.
-@end defmac
-
-@cindex @code{errno}, implicit usage
-@defmac GEN_ERRNO_RTX
-Define this macro as a C expression to create an rtl expression that
-refers to the global ``variable'' @code{errno}. (On certain systems,
-@code{errno} may not actually be a variable.) If you don't define this
-macro, a reasonable default is used.
-@end defmac
-
-@hook TARGET_LIBC_HAS_FUNCTION
-
-@hook TARGET_LIBC_HAS_FAST_FUNCTION
-
-@defmac NEXT_OBJC_RUNTIME
-Set this macro to 1 to use the "NeXT" Objective-C message sending conventions
-by default. This calling convention involves passing the object, the selector
-and the method arguments all at once to the method-lookup library function.
-This is the usual setting when targeting Darwin/Mac OS X systems, which have
-the NeXT runtime installed.
-
-If the macro is set to 0, the "GNU" Objective-C message sending convention
-will be used by default. This convention passes just the object and the
-selector to the method-lookup function, which returns a pointer to the method.
-
-In either case, it remains possible to select code-generation for the alternate
-scheme, by means of compiler command line switches.
-@end defmac
-
-@node Addressing Modes
-@section Addressing Modes
-@cindex addressing modes
-
-@c prevent bad page break with this line
-This is about addressing modes.
-
-@defmac HAVE_PRE_INCREMENT
-@defmacx HAVE_PRE_DECREMENT
-@defmacx HAVE_POST_INCREMENT
-@defmacx HAVE_POST_DECREMENT
-A C expression that is nonzero if the machine supports pre-increment,
-pre-decrement, post-increment, or post-decrement addressing respectively.
-@end defmac
-
-@defmac HAVE_PRE_MODIFY_DISP
-@defmacx HAVE_POST_MODIFY_DISP
-A C expression that is nonzero if the machine supports pre- or
-post-address side-effect generation involving constants other than
-the size of the memory operand.
-@end defmac
-
-@defmac HAVE_PRE_MODIFY_REG
-@defmacx HAVE_POST_MODIFY_REG
-A C expression that is nonzero if the machine supports pre- or
-post-address side-effect generation involving a register displacement.
-@end defmac
-
-@defmac CONSTANT_ADDRESS_P (@var{x})
-A C expression that is 1 if the RTX @var{x} is a constant which
-is a valid address. On most machines the default definition of
-@code{(CONSTANT_P (@var{x}) && GET_CODE (@var{x}) != CONST_DOUBLE)}
-is acceptable, but a few machines are more restrictive as to which
-constant addresses are supported.
-@end defmac
-
-@defmac CONSTANT_P (@var{x})
-@code{CONSTANT_P}, which is defined by target-independent code,
-accepts integer-values expressions whose values are not explicitly
-known, such as @code{symbol_ref}, @code{label_ref}, and @code{high}
-expressions and @code{const} arithmetic expressions, in addition to
-@code{const_int} and @code{const_double} expressions.
-@end defmac
-
-@defmac MAX_REGS_PER_ADDRESS
-A number, the maximum number of registers that can appear in a valid
-memory address. Note that it is up to you to specify a value equal to
-the maximum number that @code{TARGET_LEGITIMATE_ADDRESS_P} would ever
-accept.
-@end defmac
-
-@hook TARGET_LEGITIMATE_ADDRESS_P
-
-@defmac TARGET_MEM_CONSTRAINT
-A single character to be used instead of the default @code{'m'}
-character for general memory addresses. This defines the constraint
-letter which matches the memory addresses accepted by
-@code{TARGET_LEGITIMATE_ADDRESS_P}. Define this macro if you want to
-support new address formats in your back end without changing the
-semantics of the @code{'m'} constraint. This is necessary in order to
-preserve functionality of inline assembly constructs using the
-@code{'m'} constraint.
-@end defmac
-
-@defmac FIND_BASE_TERM (@var{x})
-A C expression to determine the base term of address @var{x},
-or to provide a simplified version of @var{x} from which @file{alias.cc}
-can easily find the base term. This macro is used in only two places:
-@code{find_base_value} and @code{find_base_term} in @file{alias.cc}.
-
-It is always safe for this macro to not be defined. It exists so
-that alias analysis can understand machine-dependent addresses.
-
-The typical use of this macro is to handle addresses containing
-a label_ref or symbol_ref within an UNSPEC@.
-@end defmac
-
-@hook TARGET_LEGITIMIZE_ADDRESS
-
-@defmac LEGITIMIZE_RELOAD_ADDRESS (@var{x}, @var{mode}, @var{opnum}, @var{type}, @var{ind_levels}, @var{win})
-A C compound statement that attempts to replace @var{x}, which is an address
-that needs reloading, with a valid memory address for an operand of mode
-@var{mode}. @var{win} will be a C statement label elsewhere in the code.
-It is not necessary to define this macro, but it might be useful for
-performance reasons.
-
-For example, on the i386, it is sometimes possible to use a single
-reload register instead of two by reloading a sum of two pseudo
-registers into a register. On the other hand, for number of RISC
-processors offsets are limited so that often an intermediate address
-needs to be generated in order to address a stack slot. By defining
-@code{LEGITIMIZE_RELOAD_ADDRESS} appropriately, the intermediate addresses
-generated for adjacent some stack slots can be made identical, and thus
-be shared.
-
-@emph{Note}: This macro should be used with caution. It is necessary
-to know something of how reload works in order to effectively use this,
-and it is quite easy to produce macros that build in too much knowledge
-of reload internals.
-
-@emph{Note}: This macro must be able to reload an address created by a
-previous invocation of this macro. If it fails to handle such addresses
-then the compiler may generate incorrect code or abort.
-
-@findex push_reload
-The macro definition should use @code{push_reload} to indicate parts that
-need reloading; @var{opnum}, @var{type} and @var{ind_levels} are usually
-suitable to be passed unaltered to @code{push_reload}.
-
-The code generated by this macro must not alter the substructure of
-@var{x}. If it transforms @var{x} into a more legitimate form, it
-should assign @var{x} (which will always be a C variable) a new value.
-This also applies to parts that you change indirectly by calling
-@code{push_reload}.
-
-@findex strict_memory_address_p
-The macro definition may use @code{strict_memory_address_p} to test if
-the address has become legitimate.
-
-@findex copy_rtx
-If you want to change only a part of @var{x}, one standard way of doing
-this is to use @code{copy_rtx}. Note, however, that it unshares only a
-single level of rtl. Thus, if the part to be changed is not at the
-top level, you'll need to replace first the top level.
-It is not necessary for this macro to come up with a legitimate
-address; but often a machine-dependent strategy can generate better code.
-@end defmac
-
-@hook TARGET_MODE_DEPENDENT_ADDRESS_P
-
-@hook TARGET_LEGITIMATE_CONSTANT_P
-
-@hook TARGET_PRECOMPUTE_TLS_P
-
-@hook TARGET_DELEGITIMIZE_ADDRESS
-
-@hook TARGET_CONST_NOT_OK_FOR_DEBUG_P
-
-@hook TARGET_CANNOT_FORCE_CONST_MEM
-
-@hook TARGET_USE_BLOCKS_FOR_CONSTANT_P
-
-@hook TARGET_USE_BLOCKS_FOR_DECL_P
-
-@hook TARGET_BUILTIN_RECIPROCAL
-
-@hook TARGET_VECTORIZE_BUILTIN_MASK_FOR_LOAD
-
-@hook TARGET_VECTORIZE_BUILTIN_VECTORIZATION_COST
-
-@hook TARGET_VECTORIZE_PREFERRED_VECTOR_ALIGNMENT
-
-@hook TARGET_VECTORIZE_VECTOR_ALIGNMENT_REACHABLE
-
-@hook TARGET_VECTORIZE_VEC_PERM_CONST
-
-@hook TARGET_VECTORIZE_BUILTIN_VECTORIZED_FUNCTION
-
-@hook TARGET_VECTORIZE_BUILTIN_MD_VECTORIZED_FUNCTION
-
-@hook TARGET_VECTORIZE_SUPPORT_VECTOR_MISALIGNMENT
-
-@hook TARGET_VECTORIZE_PREFERRED_SIMD_MODE
-
-@hook TARGET_VECTORIZE_SPLIT_REDUCTION
-
-@hook TARGET_VECTORIZE_AUTOVECTORIZE_VECTOR_MODES
-
-@hook TARGET_VECTORIZE_RELATED_MODE
-
-@hook TARGET_VECTORIZE_GET_MASK_MODE
-
-@hook TARGET_VECTORIZE_EMPTY_MASK_IS_EXPENSIVE
-
-@hook TARGET_VECTORIZE_CREATE_COSTS
-
-@hook TARGET_VECTORIZE_BUILTIN_GATHER
-
-@hook TARGET_VECTORIZE_BUILTIN_SCATTER
-
-@hook TARGET_SIMD_CLONE_COMPUTE_VECSIZE_AND_SIMDLEN
-
-@hook TARGET_SIMD_CLONE_ADJUST
-
-@hook TARGET_SIMD_CLONE_USABLE
-
-@hook TARGET_SIMT_VF
-
-@hook TARGET_OMP_DEVICE_KIND_ARCH_ISA
-
-@hook TARGET_GOACC_VALIDATE_DIMS
-
-@hook TARGET_GOACC_DIM_LIMIT
-
-@hook TARGET_GOACC_FORK_JOIN
-
-@hook TARGET_GOACC_REDUCTION
-
-@hook TARGET_PREFERRED_ELSE_VALUE
-
-@hook TARGET_GOACC_ADJUST_PRIVATE_DECL
-
-@hook TARGET_GOACC_EXPAND_VAR_DECL
-
-@hook TARGET_GOACC_CREATE_WORKER_BROADCAST_RECORD
-
-@hook TARGET_GOACC_SHARED_MEM_LAYOUT
-
-@node Anchored Addresses
-@section Anchored Addresses
-@cindex anchored addresses
-@cindex @option{-fsection-anchors}
-
-GCC usually addresses every static object as a separate entity.
-For example, if we have:
-
-@smallexample
-static int a, b, c;
-int foo (void) @{ return a + b + c; @}
-@end smallexample
-
-the code for @code{foo} will usually calculate three separate symbolic
-addresses: those of @code{a}, @code{b} and @code{c}. On some targets,
-it would be better to calculate just one symbolic address and access
-the three variables relative to it. The equivalent pseudocode would
-be something like:
-
-@smallexample
-int foo (void)
-@{
- register int *xr = &x;
- return xr[&a - &x] + xr[&b - &x] + xr[&c - &x];
-@}
-@end smallexample
-
-(which isn't valid C). We refer to shared addresses like @code{x} as
-``section anchors''. Their use is controlled by @option{-fsection-anchors}.
-
-The hooks below describe the target properties that GCC needs to know
-in order to make effective use of section anchors. It won't use
-section anchors at all unless either @code{TARGET_MIN_ANCHOR_OFFSET}
-or @code{TARGET_MAX_ANCHOR_OFFSET} is set to a nonzero value.
-
-@hook TARGET_MIN_ANCHOR_OFFSET
-
-@hook TARGET_MAX_ANCHOR_OFFSET
-
-@hook TARGET_ASM_OUTPUT_ANCHOR
-
-@hook TARGET_USE_ANCHORS_FOR_SYMBOL_P
-
-@node Condition Code
-@section Condition Code Status
-@cindex condition code status
-
-Condition codes in GCC are represented as registers,
-which provides better schedulability for
-architectures that do have a condition code register, but on which
-most instructions do not affect it. The latter category includes
-most RISC machines.
-
-Implicit clobbering would pose a strong restriction on the placement of
-the definition and use of the condition code. In the past the definition
-and use were always adjacent. However, recent changes to support trapping
-arithmetic may result in the definition and user being in different blocks.
-Thus, there may be a @code{NOTE_INSN_BASIC_BLOCK} between them. Additionally,
-the definition may be the source of exception handling edges.
-
-These restrictions can prevent important
-optimizations on some machines. For example, on the IBM RS/6000, there
-is a delay for taken branches unless the condition code register is set
-three instructions earlier than the conditional branch. The instruction
-scheduler cannot perform this optimization if it is not permitted to
-separate the definition and use of the condition code register.
-
-If there is a specific
-condition code register in the machine, use a hard register. If the
-condition code or comparison result can be placed in any general register,
-or if there are multiple condition registers, use a pseudo register.
-Registers used to store the condition code value will usually have a mode
-that is in class @code{MODE_CC}.
-
-Alternatively, you can use @code{BImode} if the comparison operator is
-specified already in the compare instruction. In this case, you are not
-interested in most macros in this section.
-
-@menu
-* MODE_CC Condition Codes:: Modern representation of condition codes.
-@end menu
-
-@node MODE_CC Condition Codes
-@subsection Representation of condition codes using registers
-@findex CCmode
-@findex MODE_CC
-
-@defmac SELECT_CC_MODE (@var{op}, @var{x}, @var{y})
-On many machines, the condition code may be produced by other instructions
-than compares, for example the branch can use directly the condition
-code set by a subtract instruction. However, on some machines
-when the condition code is set this way some bits (such as the overflow
-bit) are not set in the same way as a test instruction, so that a different
-branch instruction must be used for some conditional branches. When
-this happens, use the machine mode of the condition code register to
-record different formats of the condition code register. Modes can
-also be used to record which compare instruction (e.g.@: a signed or an
-unsigned comparison) produced the condition codes.
-
-If other modes than @code{CCmode} are required, add them to
-@file{@var{machine}-modes.def} and define @code{SELECT_CC_MODE} to choose
-a mode given an operand of a compare. This is needed because the modes
-have to be chosen not only during RTL generation but also, for example,
-by instruction combination. The result of @code{SELECT_CC_MODE} should
-be consistent with the mode used in the patterns; for example to support
-the case of the add on the SPARC discussed above, we have the pattern
-
-@smallexample
-(define_insn ""
- [(set (reg:CCNZ 0)
- (compare:CCNZ
- (plus:SI (match_operand:SI 0 "register_operand" "%r")
- (match_operand:SI 1 "arith_operand" "rI"))
- (const_int 0)))]
- ""
- "@dots{}")
-@end smallexample
-
-@noindent
-together with a @code{SELECT_CC_MODE} that returns @code{CCNZmode}
-for comparisons whose argument is a @code{plus}:
-
-@smallexample
-#define SELECT_CC_MODE(OP,X,Y) \
- (GET_MODE_CLASS (GET_MODE (X)) == MODE_FLOAT \
- ? ((OP == LT || OP == LE || OP == GT || OP == GE) \
- ? CCFPEmode : CCFPmode) \
- : ((GET_CODE (X) == PLUS || GET_CODE (X) == MINUS \
- || GET_CODE (X) == NEG || GET_CODE (x) == ASHIFT) \
- ? CCNZmode : CCmode))
-@end smallexample
-
-Another reason to use modes is to retain information on which operands
-were used by the comparison; see @code{REVERSIBLE_CC_MODE} later in
-this section.
-
-You should define this macro if and only if you define extra CC modes
-in @file{@var{machine}-modes.def}.
-@end defmac
-
-@hook TARGET_CANONICALIZE_COMPARISON
-
-@defmac REVERSIBLE_CC_MODE (@var{mode})
-A C expression whose value is one if it is always safe to reverse a
-comparison whose mode is @var{mode}. If @code{SELECT_CC_MODE}
-can ever return @var{mode} for a floating-point inequality comparison,
-then @code{REVERSIBLE_CC_MODE (@var{mode})} must be zero.
-
-You need not define this macro if it would always returns zero or if the
-floating-point format is anything other than @code{IEEE_FLOAT_FORMAT}.
-For example, here is the definition used on the SPARC, where floating-point
-inequality comparisons are given either @code{CCFPEmode} or @code{CCFPmode}:
-
-@smallexample
-#define REVERSIBLE_CC_MODE(MODE) \
- ((MODE) != CCFPEmode && (MODE) != CCFPmode)
-@end smallexample
-@end defmac
-
-@defmac REVERSE_CONDITION (@var{code}, @var{mode})
-A C expression whose value is reversed condition code of the @var{code} for
-comparison done in CC_MODE @var{mode}. The macro is used only in case
-@code{REVERSIBLE_CC_MODE (@var{mode})} is nonzero. Define this macro in case
-machine has some non-standard way how to reverse certain conditionals. For
-instance in case all floating point conditions are non-trapping, compiler may
-freely convert unordered compares to ordered ones. Then definition may look
-like:
-
-@smallexample
-#define REVERSE_CONDITION(CODE, MODE) \
- ((MODE) != CCFPmode ? reverse_condition (CODE) \
- : reverse_condition_maybe_unordered (CODE))
-@end smallexample
-@end defmac
-
-@hook TARGET_FIXED_CONDITION_CODE_REGS
-
-@hook TARGET_CC_MODES_COMPATIBLE
-
-@hook TARGET_FLAGS_REGNUM
-
-@node Costs
-@section Describing Relative Costs of Operations
-@cindex costs of instructions
-@cindex relative costs
-@cindex speed of instructions
-
-These macros let you describe the relative speed of various operations
-on the target machine.
-
-@defmac REGISTER_MOVE_COST (@var{mode}, @var{from}, @var{to})
-A C expression for the cost of moving data of mode @var{mode} from a
-register in class @var{from} to one in class @var{to}. The classes are
-expressed using the enumeration values such as @code{GENERAL_REGS}. A
-value of 2 is the default; other values are interpreted relative to
-that.
-
-It is not required that the cost always equal 2 when @var{from} is the
-same as @var{to}; on some machines it is expensive to move between
-registers if they are not general registers.
-
-If reload sees an insn consisting of a single @code{set} between two
-hard registers, and if @code{REGISTER_MOVE_COST} applied to their
-classes returns a value of 2, reload does not check to ensure that the
-constraints of the insn are met. Setting a cost of other than 2 will
-allow reload to verify that the constraints are met. You should do this
-if the @samp{mov@var{m}} pattern's constraints do not allow such copying.
-
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_REGISTER_MOVE_COST} instead.
-@end defmac
-
-@hook TARGET_REGISTER_MOVE_COST
-
-@defmac MEMORY_MOVE_COST (@var{mode}, @var{class}, @var{in})
-A C expression for the cost of moving data of mode @var{mode} between a
-register of class @var{class} and memory; @var{in} is zero if the value
-is to be written to memory, nonzero if it is to be read in. This cost
-is relative to those in @code{REGISTER_MOVE_COST}. If moving between
-registers and memory is more expensive than between two registers, you
-should define this macro to express the relative cost.
-
-If you do not define this macro, GCC uses a default cost of 4 plus
-the cost of copying via a secondary reload register, if one is
-needed. If your machine requires a secondary reload register to copy
-between memory and a register of @var{class} but the reload mechanism is
-more complex than copying via an intermediate, define this macro to
-reflect the actual cost of the move.
-
-GCC defines the function @code{memory_move_secondary_cost} if
-secondary reloads are needed. It computes the costs due to copying via
-a secondary register. If your machine copies from memory using a
-secondary register in the conventional way but the default base value of
-4 is not correct for your machine, define this macro to add some other
-value to the result of that function. The arguments to that function
-are the same as to this macro.
-
-These macros are obsolete, new ports should use the target hook
-@code{TARGET_MEMORY_MOVE_COST} instead.
-@end defmac
-
-@hook TARGET_MEMORY_MOVE_COST
-
-@defmac BRANCH_COST (@var{speed_p}, @var{predictable_p})
-A C expression for the cost of a branch instruction. A value of 1 is
-the default; other values are interpreted relative to that. Parameter
-@var{speed_p} is true when the branch in question should be optimized
-for speed. When it is false, @code{BRANCH_COST} should return a value
-optimal for code size rather than performance. @var{predictable_p} is
-true for well-predicted branches. On many architectures the
-@code{BRANCH_COST} can be reduced then.
-@end defmac
-
-Here are additional macros which do not specify precise relative costs,
-but only that certain actions are more expensive than GCC would
-ordinarily expect.
-
-@defmac SLOW_BYTE_ACCESS
-Define this macro as a C expression which is nonzero if accessing less
-than a word of memory (i.e.@: a @code{char} or a @code{short}) is no
-faster than accessing a word of memory, i.e., if such access
-require more than one instruction or if there is no difference in cost
-between byte and (aligned) word loads.
-
-When this macro is not defined, the compiler will access a field by
-finding the smallest containing object; when it is defined, a fullword
-load will be used if alignment permits. Unless bytes accesses are
-faster than word accesses, using word accesses is preferable since it
-may eliminate subsequent memory access if subsequent accesses occur to
-other fields in the same word of the structure, but to different bytes.
-@end defmac
-
-@hook TARGET_SLOW_UNALIGNED_ACCESS
-
-@defmac MOVE_RATIO (@var{speed})
-The threshold of number of scalar memory-to-memory move insns, @emph{below}
-which a sequence of insns should be generated instead of a
-string move insn or a library call. Increasing the value will always
-make code faster, but eventually incurs high cost in increased code size.
-
-Note that on machines where the corresponding move insn is a
-@code{define_expand} that emits a sequence of insns, this macro counts
-the number of such sequences.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, a reasonable default is used.
-@end defmac
-
-@hook TARGET_USE_BY_PIECES_INFRASTRUCTURE_P
-
-@hook TARGET_OVERLAP_OP_BY_PIECES_P
-
-@hook TARGET_COMPARE_BY_PIECES_BRANCH_RATIO
-
-@defmac MOVE_MAX_PIECES
-A C expression used by @code{move_by_pieces} to determine the largest unit
-a load or store used to copy memory is. Defaults to @code{MOVE_MAX}.
-@end defmac
-
-@defmac STORE_MAX_PIECES
-A C expression used by @code{store_by_pieces} to determine the largest unit
-a store used to memory is. Defaults to @code{MOVE_MAX_PIECES}, or two times
-the size of @code{HOST_WIDE_INT}, whichever is smaller.
-@end defmac
-
-@defmac COMPARE_MAX_PIECES
-A C expression used by @code{compare_by_pieces} to determine the largest unit
-a load or store used to compare memory is. Defaults to
-@code{MOVE_MAX_PIECES}.
-@end defmac
-
-@defmac CLEAR_RATIO (@var{speed})
-The threshold of number of scalar move insns, @emph{below} which a sequence
-of insns should be generated to clear memory instead of a string clear insn
-or a library call. Increasing the value will always make code faster, but
-eventually incurs high cost in increased code size.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, a reasonable default is used.
-@end defmac
-
-@defmac SET_RATIO (@var{speed})
-The threshold of number of scalar move insns, @emph{below} which a sequence
-of insns should be generated to set memory to a constant value, instead of
-a block set insn or a library call.
-Increasing the value will always make code faster, but
-eventually incurs high cost in increased code size.
-
-The parameter @var{speed} is true if the code is currently being
-optimized for speed rather than size.
-
-If you don't define this, it defaults to the value of @code{MOVE_RATIO}.
-@end defmac
-
-@defmac USE_LOAD_POST_INCREMENT (@var{mode})
-A C expression used to determine whether a load postincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_INCREMENT}.
-@end defmac
-
-@defmac USE_LOAD_POST_DECREMENT (@var{mode})
-A C expression used to determine whether a load postdecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_DECREMENT}.
-@end defmac
-
-@defmac USE_LOAD_PRE_INCREMENT (@var{mode})
-A C expression used to determine whether a load preincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_INCREMENT}.
-@end defmac
-
-@defmac USE_LOAD_PRE_DECREMENT (@var{mode})
-A C expression used to determine whether a load predecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_DECREMENT}.
-@end defmac
-
-@defmac USE_STORE_POST_INCREMENT (@var{mode})
-A C expression used to determine whether a store postincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_INCREMENT}.
-@end defmac
-
-@defmac USE_STORE_POST_DECREMENT (@var{mode})
-A C expression used to determine whether a store postdecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_POST_DECREMENT}.
-@end defmac
-
-@defmac USE_STORE_PRE_INCREMENT (@var{mode})
-This macro is used to determine whether a store preincrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_INCREMENT}.
-@end defmac
-
-@defmac USE_STORE_PRE_DECREMENT (@var{mode})
-This macro is used to determine whether a store predecrement is a good
-thing to use for a given mode. Defaults to the value of
-@code{HAVE_PRE_DECREMENT}.
-@end defmac
-
-@defmac NO_FUNCTION_CSE
-Define this macro to be true if it is as good or better to call a constant
-function address than to call an address kept in a register.
-@end defmac
-
-@defmac LOGICAL_OP_NON_SHORT_CIRCUIT
-Define this macro if a non-short-circuit operation produced by
-@samp{fold_range_test ()} is optimal. This macro defaults to true if
-@code{BRANCH_COST} is greater than or equal to the value 2.
-@end defmac
-
-@hook TARGET_OPTAB_SUPPORTED_P
-
-@hook TARGET_RTX_COSTS
-
-@hook TARGET_ADDRESS_COST
-
-@hook TARGET_INSN_COST
-
-@hook TARGET_MAX_NOCE_IFCVT_SEQ_COST
-
-@hook TARGET_NOCE_CONVERSION_PROFITABLE_P
-
-@hook TARGET_NEW_ADDRESS_PROFITABLE_P
-
-@hook TARGET_NO_SPECULATION_IN_DELAY_SLOTS_P
-
-@hook TARGET_ESTIMATED_POLY_VALUE
-
-@node Scheduling
-@section Adjusting the Instruction Scheduler
-
-The instruction scheduler may need a fair amount of machine-specific
-adjustment in order to produce good code. GCC provides several target
-hooks for this purpose. It is usually enough to define just a few of
-them: try the first ones in this list first.
-
-@hook TARGET_SCHED_ISSUE_RATE
-
-@hook TARGET_SCHED_VARIABLE_ISSUE
-
-@hook TARGET_SCHED_ADJUST_COST
-
-@hook TARGET_SCHED_ADJUST_PRIORITY
-
-@hook TARGET_SCHED_REORDER
-
-@hook TARGET_SCHED_REORDER2
-
-@hook TARGET_SCHED_MACRO_FUSION_P
-
-@hook TARGET_SCHED_MACRO_FUSION_PAIR_P
-
-@hook TARGET_SCHED_DEPENDENCIES_EVALUATION_HOOK
-
-@hook TARGET_SCHED_INIT
-
-@hook TARGET_SCHED_FINISH
-
-@hook TARGET_SCHED_INIT_GLOBAL
-
-@hook TARGET_SCHED_FINISH_GLOBAL
-
-@hook TARGET_SCHED_DFA_PRE_CYCLE_INSN
-
-@hook TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN
-
-@hook TARGET_SCHED_DFA_POST_CYCLE_INSN
-
-@hook TARGET_SCHED_INIT_DFA_POST_CYCLE_INSN
-
-@hook TARGET_SCHED_DFA_PRE_ADVANCE_CYCLE
-
-@hook TARGET_SCHED_DFA_POST_ADVANCE_CYCLE
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BEGIN
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_ISSUE
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_BACKTRACK
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_END
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_INIT
-
-@hook TARGET_SCHED_FIRST_CYCLE_MULTIPASS_FINI
-
-@hook TARGET_SCHED_DFA_NEW_CYCLE
-
-@hook TARGET_SCHED_IS_COSTLY_DEPENDENCE
-
-@hook TARGET_SCHED_H_I_D_EXTENDED
-
-@hook TARGET_SCHED_ALLOC_SCHED_CONTEXT
-
-@hook TARGET_SCHED_INIT_SCHED_CONTEXT
-
-@hook TARGET_SCHED_SET_SCHED_CONTEXT
-
-@hook TARGET_SCHED_CLEAR_SCHED_CONTEXT
-
-@hook TARGET_SCHED_FREE_SCHED_CONTEXT
-
-@hook TARGET_SCHED_SPECULATE_INSN
-
-@hook TARGET_SCHED_NEEDS_BLOCK_P
-
-@hook TARGET_SCHED_GEN_SPEC_CHECK
-
-@hook TARGET_SCHED_SET_SCHED_FLAGS
-
-@hook TARGET_SCHED_CAN_SPECULATE_INSN
-
-@hook TARGET_SCHED_SMS_RES_MII
-
-@hook TARGET_SCHED_DISPATCH
-
-@hook TARGET_SCHED_DISPATCH_DO
-
-@hook TARGET_SCHED_EXPOSED_PIPELINE
-
-@hook TARGET_SCHED_REASSOCIATION_WIDTH
-
-@hook TARGET_SCHED_FUSION_PRIORITY
-
-@hook TARGET_EXPAND_DIVMOD_LIBFUNC
-
-@node Sections
-@section Dividing the Output into Sections (Texts, Data, @dots{})
-@c the above section title is WAY too long. maybe cut the part between
-@c the (...)? --mew 10feb93
-
-An object file is divided into sections containing different types of
-data. In the most common case, there are three sections: the @dfn{text
-section}, which holds instructions and read-only data; the @dfn{data
-section}, which holds initialized writable data; and the @dfn{bss
-section}, which holds uninitialized data. Some systems have other kinds
-of sections.
-
-@file{varasm.cc} provides several well-known sections, such as
-@code{text_section}, @code{data_section} and @code{bss_section}.
-The normal way of controlling a @code{@var{foo}_section} variable
-is to define the associated @code{@var{FOO}_SECTION_ASM_OP} macro,
-as described below. The macros are only read once, when @file{varasm.cc}
-initializes itself, so their values must be run-time constants.
-They may however depend on command-line flags.
-
-@emph{Note:} Some run-time files, such @file{crtstuff.c}, also make
-use of the @code{@var{FOO}_SECTION_ASM_OP} macros, and expect them
-to be string literals.
-
-Some assemblers require a different string to be written every time a
-section is selected. If your assembler falls into this category, you
-should define the @code{TARGET_ASM_INIT_SECTIONS} hook and use
-@code{get_unnamed_section} to set up the sections.
-
-You must always create a @code{text_section}, either by defining
-@code{TEXT_SECTION_ASM_OP} or by initializing @code{text_section}
-in @code{TARGET_ASM_INIT_SECTIONS}. The same is true of
-@code{data_section} and @code{DATA_SECTION_ASM_OP}. If you do not
-create a distinct @code{readonly_data_section}, the default is to
-reuse @code{text_section}.
-
-All the other @file{varasm.cc} sections are optional, and are null
-if the target does not provide them.
-
-@defmac TEXT_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation that should precede instructions and read-only data.
-Normally @code{"\t.text"} is right.
-@end defmac
-
-@defmac HOT_TEXT_SECTION_NAME
-If defined, a C string constant for the name of the section containing most
-frequently executed functions of the program. If not defined, GCC will provide
-a default definition if the target supports named sections.
-@end defmac
-
-@defmac UNLIKELY_EXECUTED_TEXT_SECTION_NAME
-If defined, a C string constant for the name of the section containing unlikely
-executed functions in the program.
-@end defmac
-
-@defmac DATA_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation to identify the following data as writable initialized
-data. Normally @code{"\t.data"} is right.
-@end defmac
-
-@defmac SDATA_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-initialized, writable small data.
-@end defmac
-
-@defmac READONLY_DATA_SECTION_ASM_OP
-A C expression whose value is a string, including spacing, containing the
-assembler operation to identify the following data as read-only initialized
-data.
-@end defmac
-
-@defmac BSS_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-uninitialized global data. If not defined, and
-@code{ASM_OUTPUT_ALIGNED_BSS} not defined,
-uninitialized global data will be output in the data section if
-@option{-fno-common} is passed, otherwise @code{ASM_OUTPUT_COMMON} will be
-used.
-@end defmac
-
-@defmac SBSS_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-uninitialized, writable small data.
-@end defmac
-
-@defmac TLS_COMMON_ASM_OP
-If defined, a C expression whose value is a string containing the
-assembler operation to identify the following data as thread-local
-common data. The default is @code{".tls_common"}.
-@end defmac
-
-@defmac TLS_SECTION_ASM_FLAG
-If defined, a C expression whose value is a character constant
-containing the flag used to mark a section as a TLS section. The
-default is @code{'T'}.
-@end defmac
-
-@defmac INIT_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-initialization code. If not defined, GCC will assume such a section does
-not exist. This section has no corresponding @code{init_section}
-variable; it is used entirely in runtime code.
-@end defmac
-
-@defmac FINI_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-finalization code. If not defined, GCC will assume such a section does
-not exist. This section has no corresponding @code{fini_section}
-variable; it is used entirely in runtime code.
-@end defmac
-
-@defmac INIT_ARRAY_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-part of the @code{.init_array} (or equivalent) section. If not
-defined, GCC will assume such a section does not exist. Do not define
-both this macro and @code{INIT_SECTION_ASM_OP}.
-@end defmac
-
-@defmac FINI_ARRAY_SECTION_ASM_OP
-If defined, a C expression whose value is a string, including spacing,
-containing the assembler operation to identify the following data as
-part of the @code{.fini_array} (or equivalent) section. If not
-defined, GCC will assume such a section does not exist. Do not define
-both this macro and @code{FINI_SECTION_ASM_OP}.
-@end defmac
-
-@defmac MACH_DEP_SECTION_ASM_FLAG
-If defined, a C expression whose value is a character constant
-containing the flag used to mark a machine-dependent section. This
-corresponds to the @code{SECTION_MACH_DEP} section flag.
-@end defmac
-
-@defmac CRT_CALL_STATIC_FUNCTION (@var{section_op}, @var{function})
-If defined, an ASM statement that switches to a different section
-via @var{section_op}, calls @var{function}, and switches back to
-the text section. This is used in @file{crtstuff.c} if
-@code{INIT_SECTION_ASM_OP} or @code{FINI_SECTION_ASM_OP} to calls
-to initialization and finalization functions from the init and fini
-sections. By default, this macro uses a simple function call. Some
-ports need hand-crafted assembly code to avoid dependencies on
-registers initialized in the function prologue or to ensure that
-constant pools don't end up too far way in the text section.
-@end defmac
-
-@defmac TARGET_LIBGCC_SDATA_SECTION
-If defined, a string which names the section into which small
-variables defined in crtstuff and libgcc should go. This is useful
-when the target has options for optimizing access to small data, and
-you want the crtstuff and libgcc routines to be conservative in what
-they expect of your application yet liberal in what your application
-expects. For example, for targets with a @code{.sdata} section (like
-MIPS), you could compile crtstuff with @code{-G 0} so that it doesn't
-require small data support from your application, but use this macro
-to put small data into @code{.sdata} so that your application can
-access these variables whether it uses small data or not.
-@end defmac
-
-@defmac FORCE_CODE_SECTION_ALIGN
-If defined, an ASM statement that aligns a code section to some
-arbitrary boundary. This is used to force all fragments of the
-@code{.init} and @code{.fini} sections to have to same alignment
-and thus prevent the linker from having to add any padding.
-@end defmac
-
-@defmac JUMP_TABLES_IN_TEXT_SECTION
-Define this macro to be an expression with a nonzero value if jump
-tables (for @code{tablejump} insns) should be output in the text
-section, along with the assembler instructions. Otherwise, the
-readonly data section is used.
-
-This macro is irrelevant if there is no separate readonly data section.
-@end defmac
-
-@hook TARGET_ASM_INIT_SECTIONS
-
-@hook TARGET_ASM_RELOC_RW_MASK
-
-@hook TARGET_ASM_GENERATE_PIC_ADDR_DIFF_VEC
-
-@hook TARGET_ASM_SELECT_SECTION
-
-@defmac USE_SELECT_SECTION_FOR_FUNCTIONS
-Define this macro if you wish TARGET_ASM_SELECT_SECTION to be called
-for @code{FUNCTION_DECL}s as well as for variables and constants.
-
-In the case of a @code{FUNCTION_DECL}, @var{reloc} will be zero if the
-function has been determined to be likely to be called, and nonzero if
-it is unlikely to be called.
-@end defmac
-
-@hook TARGET_ASM_UNIQUE_SECTION
-
-@hook TARGET_ASM_FUNCTION_RODATA_SECTION
-
-@hook TARGET_ASM_MERGEABLE_RODATA_PREFIX
-
-@hook TARGET_ASM_TM_CLONE_TABLE_SECTION
-
-@hook TARGET_ASM_SELECT_RTX_SECTION
-
-@hook TARGET_MANGLE_DECL_ASSEMBLER_NAME
-
-@hook TARGET_ENCODE_SECTION_INFO
-
-@hook TARGET_STRIP_NAME_ENCODING
-
-@hook TARGET_IN_SMALL_DATA_P
-
-@hook TARGET_HAVE_SRODATA_SECTION
-
-@hook TARGET_PROFILE_BEFORE_PROLOGUE
-
-@hook TARGET_BINDS_LOCAL_P
-
-@hook TARGET_HAVE_TLS
-
-
-@node PIC
-@section Position Independent Code
-@cindex position independent code
-@cindex PIC
-
-This section describes macros that help implement generation of position
-independent code. Simply defining these macros is not enough to
-generate valid PIC; you must also add support to the hook
-@code{TARGET_LEGITIMATE_ADDRESS_P} and to the macro
-@code{PRINT_OPERAND_ADDRESS}, as well as @code{LEGITIMIZE_ADDRESS}. You
-must modify the definition of @samp{movsi} to do something appropriate
-when the source operand contains a symbolic address. You may also
-need to alter the handling of switch statements so that they use
-relative addresses.
-@c i rearranged the order of the macros above to try to force one of
-@c them to the next line, to eliminate an overfull hbox. --mew 10feb93
-
-@defmac PIC_OFFSET_TABLE_REGNUM
-The register number of the register used to address a table of static
-data addresses in memory. In some cases this register is defined by a
-processor's ``application binary interface'' (ABI)@. When this macro
-is defined, RTL is generated for this register once, as with the stack
-pointer and frame pointer registers. If this macro is not defined, it
-is up to the machine-dependent files to allocate such a register (if
-necessary). Note that this register must be fixed when in use (e.g.@:
-when @code{flag_pic} is true).
-@end defmac
-
-@defmac PIC_OFFSET_TABLE_REG_CALL_CLOBBERED
-A C expression that is nonzero if the register defined by
-@code{PIC_OFFSET_TABLE_REGNUM} is clobbered by calls. If not defined,
-the default is zero. Do not define
-this macro if @code{PIC_OFFSET_TABLE_REGNUM} is not defined.
-@end defmac
-
-@defmac LEGITIMATE_PIC_OPERAND_P (@var{x})
-A C expression that is nonzero if @var{x} is a legitimate immediate
-operand on the target machine when generating position independent code.
-You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not
-check this. You can also assume @var{flag_pic} is true, so you need not
-check it either. You need not define this macro if all constants
-(including @code{SYMBOL_REF}) can be immediate operands when generating
-position independent code.
-@end defmac
-
-@node Assembler Format
-@section Defining the Output Assembler Language
-
-This section describes macros whose principal purpose is to describe how
-to write instructions in assembler language---rather than what the
-instructions do.
-
-@menu
-* File Framework:: Structural information for the assembler file.
-* Data Output:: Output of constants (numbers, strings, addresses).
-* Uninitialized Data:: Output of uninitialized variables.
-* Label Output:: Output and generation of labels.
-* Initialization:: General principles of initialization
- and termination routines.
-* Macros for Initialization::
- Specific macros that control the handling of
- initialization and termination routines.
-* Instruction Output:: Output of actual instructions.
-* Dispatch Tables:: Output of jump tables.
-* Exception Region Output:: Output of exception region code.
-* Alignment Output:: Pseudo ops for alignment and skipping data.
-@end menu
-
-@node File Framework
-@subsection The Overall Framework of an Assembler File
-@cindex assembler format
-@cindex output of assembler code
-
-@c prevent bad page break with this line
-This describes the overall framework of an assembly file.
-
-@findex default_file_start
-@hook TARGET_ASM_FILE_START
-
-@hook TARGET_ASM_FILE_START_APP_OFF
-
-@hook TARGET_ASM_FILE_START_FILE_DIRECTIVE
-
-@hook TARGET_ASM_FILE_END
-
-@deftypefun void file_end_indicate_exec_stack ()
-Some systems use a common convention, the @samp{.note.GNU-stack}
-special section, to indicate whether or not an object file relies on
-the stack being executable. If your system uses this convention, you
-should define @code{TARGET_ASM_FILE_END} to this function. If you
-need to do other things in that hook, have your hook function call
-this function.
-@end deftypefun
-
-@hook TARGET_ASM_LTO_START
-
-@hook TARGET_ASM_LTO_END
-
-@hook TARGET_ASM_CODE_END
-
-@defmac ASM_COMMENT_START
-A C string constant describing how to begin a comment in the target
-assembler language. The compiler assumes that the comment will end at
-the end of the line.
-@end defmac
-
-@defmac ASM_APP_ON
-A C string constant for text to be output before each @code{asm}
-statement or group of consecutive ones. Normally this is
-@code{"#APP"}, which is a comment that has no effect on most
-assemblers but tells the GNU assembler that it must check the lines
-that follow for all valid assembler constructs.
-@end defmac
-
-@defmac ASM_APP_OFF
-A C string constant for text to be output after each @code{asm}
-statement or group of consecutive ones. Normally this is
-@code{"#NO_APP"}, which tells the GNU assembler to resume making the
-time-saving assumptions that are valid for ordinary compiler output.
-@end defmac
-
-@defmac ASM_OUTPUT_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output COFF information or DWARF debugging information
-which indicates that filename @var{name} is the current source file to
-the stdio stream @var{stream}.
-
-This macro need not be defined if the standard form of output
-for the file format in use is appropriate.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_SOURCE_FILENAME
-
-@hook TARGET_ASM_OUTPUT_IDENT
-
-@defmac OUTPUT_QUOTED_STRING (@var{stream}, @var{string})
-A C statement to output the string @var{string} to the stdio stream
-@var{stream}. If you do not call the function @code{output_quoted_string}
-in your config files, GCC will only call it to output filenames to
-the assembler source. So you can use it to canonicalize the format
-of the filename using this macro.
-@end defmac
-
-@hook TARGET_ASM_NAMED_SECTION
-
-@hook TARGET_ASM_ELF_FLAGS_NUMERIC
-
-@hook TARGET_ASM_FUNCTION_SECTION
-
-@hook TARGET_ASM_FUNCTION_SWITCHED_TEXT_SECTIONS
-
-@hook TARGET_HAVE_NAMED_SECTIONS
-This flag is true if the target supports @code{TARGET_ASM_NAMED_SECTION}.
-It must not be modified by command-line option processing.
-@end deftypevr
-
-@anchor{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}
-@hook TARGET_HAVE_SWITCHABLE_BSS_SECTIONS
-
-@hook TARGET_SECTION_TYPE_FLAGS
-
-@hook TARGET_ASM_RECORD_GCC_SWITCHES
-
-@hook TARGET_ASM_RECORD_GCC_SWITCHES_SECTION
-
-@need 2000
-@node Data Output
-@subsection Output of Data
-
-
-@hook TARGET_ASM_BYTE_OP
-
-@hook TARGET_ASM_INTEGER
-
-@hook TARGET_ASM_DECL_END
-
-@hook TARGET_ASM_OUTPUT_ADDR_CONST_EXTRA
-
-@defmac ASM_OUTPUT_ASCII (@var{stream}, @var{ptr}, @var{len})
-A C statement to output to the stdio stream @var{stream} an assembler
-instruction to assemble a string constant containing the @var{len}
-bytes at @var{ptr}. @var{ptr} will be a C expression of type
-@code{char *} and @var{len} a C expression of type @code{int}.
-
-If the assembler has a @code{.ascii} pseudo-op as found in the
-Berkeley Unix assembler, do not define the macro
-@code{ASM_OUTPUT_ASCII}.
-@end defmac
-
-@defmac ASM_OUTPUT_FDESC (@var{stream}, @var{decl}, @var{n})
-A C statement to output word @var{n} of a function descriptor for
-@var{decl}. This must be defined if @code{TARGET_VTABLE_USES_DESCRIPTORS}
-is defined, and is otherwise unused.
-@end defmac
-
-@defmac CONSTANT_POOL_BEFORE_FUNCTION
-You may define this macro as a C expression. You should define the
-expression to have a nonzero value if GCC should output the constant
-pool for a function before the code for the function, or a zero value if
-GCC should output the constant pool after the function. If you do
-not define this macro, the usual case, GCC will output the constant
-pool before the function.
-@end defmac
-
-@defmac ASM_OUTPUT_POOL_PROLOGUE (@var{file}, @var{funname}, @var{fundecl}, @var{size})
-A C statement to output assembler commands to define the start of the
-constant pool for a function. @var{funname} is a string giving
-the name of the function. Should the return type of the function
-be required, it can be obtained via @var{fundecl}. @var{size}
-is the size, in bytes, of the constant pool that will be written
-immediately after this call.
-
-If no constant-pool prefix is required, the usual case, this macro need
-not be defined.
-@end defmac
-
-@defmac ASM_OUTPUT_SPECIAL_POOL_ENTRY (@var{file}, @var{x}, @var{mode}, @var{align}, @var{labelno}, @var{jumpto})
-A C statement (with or without semicolon) to output a constant in the
-constant pool, if it needs special treatment. (This macro need not do
-anything for RTL expressions that can be output normally.)
-
-The argument @var{file} is the standard I/O stream to output the
-assembler code on. @var{x} is the RTL expression for the constant to
-output, and @var{mode} is the machine mode (in case @var{x} is a
-@samp{const_int}). @var{align} is the required alignment for the value
-@var{x}; you should output an assembler directive to force this much
-alignment.
-
-The argument @var{labelno} is a number to use in an internal label for
-the address of this pool entry. The definition of this macro is
-responsible for outputting the label definition at the proper place.
-Here is how to do this:
-
-@smallexample
-@code{(*targetm.asm_out.internal_label)} (@var{file}, "LC", @var{labelno});
-@end smallexample
-
-When you output a pool entry specially, you should end with a
-@code{goto} to the label @var{jumpto}. This will prevent the same pool
-entry from being output a second time in the usual manner.
-
-You need not define this macro if it would do nothing.
-@end defmac
-
-@defmac ASM_OUTPUT_POOL_EPILOGUE (@var{file} @var{funname} @var{fundecl} @var{size})
-A C statement to output assembler commands to at the end of the constant
-pool for a function. @var{funname} is a string giving the name of the
-function. Should the return type of the function be required, you can
-obtain it via @var{fundecl}. @var{size} is the size, in bytes, of the
-constant pool that GCC wrote immediately before this call.
-
-If no constant-pool epilogue is required, the usual case, you need not
-define this macro.
-@end defmac
-
-@defmac IS_ASM_LOGICAL_LINE_SEPARATOR (@var{C}, @var{STR})
-Define this macro as a C expression which is nonzero if @var{C} is
-used as a logical line separator by the assembler. @var{STR} points
-to the position in the string where @var{C} was found; this can be used if
-a line separator uses multiple characters.
-
-If you do not define this macro, the default is that only
-the character @samp{;} is treated as a logical line separator.
-@end defmac
-
-@hook TARGET_ASM_OPEN_PAREN
-
-These macros are provided by @file{real.h} for writing the definitions
-of @code{ASM_OUTPUT_DOUBLE} and the like:
-
-@defmac REAL_VALUE_TO_TARGET_SINGLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DOUBLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_LONG_DOUBLE (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL32 (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL64 (@var{x}, @var{l})
-@defmacx REAL_VALUE_TO_TARGET_DECIMAL128 (@var{x}, @var{l})
-These translate @var{x}, of type @code{REAL_VALUE_TYPE}, to the
-target's floating point representation, and store its bit pattern in
-the variable @var{l}. For @code{REAL_VALUE_TO_TARGET_SINGLE} and
-@code{REAL_VALUE_TO_TARGET_DECIMAL32}, this variable should be a
-simple @code{long int}. For the others, it should be an array of
-@code{long int}. The number of elements in this array is determined
-by the size of the desired target floating point data type: 32 bits of
-it go in each @code{long int} array element. Each array element holds
-32 bits of the result, even if @code{long int} is wider than 32 bits
-on the host machine.
-
-The array element values are designed so that you can print them out
-using @code{fprintf} in the order they should appear in the target
-machine's memory.
-@end defmac
-
-@node Uninitialized Data
-@subsection Output of Uninitialized Variables
-
-Each of the macros in this section is used to do the whole job of
-outputting a single uninitialized variable.
-
-@defmac ASM_OUTPUT_COMMON (@var{stream}, @var{name}, @var{size}, @var{rounded})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a common-label named
-@var{name} whose size is @var{size} bytes. The variable @var{rounded}
-is the size rounded up to whatever alignment the caller wants. It is
-possible that @var{size} may be zero, for instance if a struct with no
-other member than a zero-length array is defined. In this case, the
-backend must output a symbol definition that allocates at least one
-byte, both so that the address of the resulting object does not compare
-equal to any other, and because some object formats cannot even express
-the concept of a zero-sized common symbol, as that is how they represent
-an ordinary undefined external.
-
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline.
-
-This macro controls how the assembler definitions of uninitialized
-common global variables are output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_COMMON (@var{stream}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_COMMON} except takes the required alignment as a
-separate, explicit argument. If you define this macro, it is used in
-place of @code{ASM_OUTPUT_COMMON}, and gives you more flexibility in
-handling the required alignment of the variable. The alignment is specified
-as the number of bits.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_DECL_COMMON (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_ALIGNED_COMMON} except that @var{decl} of the
-variable to be output, if there is one, or @code{NULL_TREE} if there
-is no corresponding variable. If you define this macro, GCC will use it
-in place of both @code{ASM_OUTPUT_COMMON} and
-@code{ASM_OUTPUT_ALIGNED_COMMON}. Define this macro when you need to see
-the variable's decl in order to chose what to output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_BSS (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of uninitialized global @var{decl} named
-@var{name} whose size is @var{size} bytes. The variable @var{alignment}
-is the alignment specified as the number of bits.
-
-Try to use function @code{asm_output_aligned_bss} defined in file
-@file{varasm.cc} when defining this macro. If unable, use the expression
-@code{assemble_name (@var{stream}, @var{name})} to output the name itself;
-before and after that, output the additional assembler syntax for defining
-the name, and a newline.
-
-There are two ways of handling global BSS@. One is to define this macro.
-The other is to have @code{TARGET_ASM_SELECT_SECTION} return a
-switchable BSS section (@pxref{TARGET_HAVE_SWITCHABLE_BSS_SECTIONS}).
-You do not need to do both.
-
-Some languages do not have @code{common} data, and require a
-non-common form of global BSS in order to handle uninitialized globals
-efficiently. C++ is one example of this. However, if the target does
-not support global BSS, the front end may choose to make globals
-common in order to save space in the object file.
-@end defmac
-
-@defmac ASM_OUTPUT_LOCAL (@var{stream}, @var{name}, @var{size}, @var{rounded})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a local-common-label named
-@var{name} whose size is @var{size} bytes. The variable @var{rounded}
-is the size rounded up to whatever alignment the caller wants.
-
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline.
-
-This macro controls how the assembler definitions of uninitialized
-static variables are output.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_LOCAL (@var{stream}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_LOCAL} except takes the required alignment as a
-separate, explicit argument. If you define this macro, it is used in
-place of @code{ASM_OUTPUT_LOCAL}, and gives you more flexibility in
-handling the required alignment of the variable. The alignment is specified
-as the number of bits.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGNED_DECL_LOCAL (@var{stream}, @var{decl}, @var{name}, @var{size}, @var{alignment})
-Like @code{ASM_OUTPUT_ALIGNED_LOCAL} except that @var{decl} of the
-variable to be output, if there is one, or @code{NULL_TREE} if there
-is no corresponding variable. If you define this macro, GCC will use it
-in place of both @code{ASM_OUTPUT_LOCAL} and
-@code{ASM_OUTPUT_ALIGNED_LOCAL}. Define this macro when you need to see
-the variable's decl in order to chose what to output.
-@end defmac
-
-@node Label Output
-@subsection Output and Generation of Labels
-
-@c prevent bad page break with this line
-This is about outputting labels.
-
-@findex assemble_name
-@defmac ASM_OUTPUT_LABEL (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a label named @var{name}.
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline. A default
-definition of this macro is provided which is correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_FUNCTION_LABEL (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} the assembler definition of a label named @var{name} of
-a function.
-Use the expression @code{assemble_name (@var{stream}, @var{name})} to
-output the name itself; before and after that, output the additional
-assembler syntax for defining the name, and a newline. A default
-definition of this macro is provided which is correct for most systems.
-
-If this macro is not defined, then the function name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-@end defmac
-
-@findex assemble_name_raw
-@defmac ASM_OUTPUT_INTERNAL_LABEL (@var{stream}, @var{name})
-Identical to @code{ASM_OUTPUT_LABEL}, except that @var{name} is known
-to refer to a compiler-generated label. The default definition uses
-@code{assemble_name_raw}, which is like @code{assemble_name} except
-that it is more efficient.
-@end defmac
-
-@defmac SIZE_ASM_OP
-A C string containing the appropriate assembler directive to specify the
-size of a symbol, without any arguments. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"\t.size\t"}; on other
-systems, the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definitions
-of @code{ASM_OUTPUT_SIZE_DIRECTIVE} and @code{ASM_OUTPUT_MEASURED_SIZE}
-for your system. If you need your own custom definitions of those
-macros, or if you do not need explicit symbol sizes at all, do not
-define this macro.
-@end defmac
-
-@defmac ASM_OUTPUT_SIZE_DIRECTIVE (@var{stream}, @var{name}, @var{size})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler that the size of the
-symbol @var{name} is @var{size}. @var{size} is a @code{HOST_WIDE_INT}.
-If you define @code{SIZE_ASM_OP}, a default definition of this macro is
-provided.
-@end defmac
-
-@defmac ASM_OUTPUT_MEASURED_SIZE (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler to calculate the size of
-the symbol @var{name} by subtracting its address from the current
-address.
-
-If you define @code{SIZE_ASM_OP}, a default definition of this macro is
-provided. The default assumes that the assembler recognizes a special
-@samp{.} symbol as referring to the current address, and can calculate
-the difference between this and another symbol. If your assembler does
-not recognize @samp{.} or cannot do calculations with it, you will need
-to redefine @code{ASM_OUTPUT_MEASURED_SIZE} to use some other technique.
-@end defmac
-
-@defmac NO_DOLLAR_IN_LABEL
-Define this macro if the assembler does not accept the character
-@samp{$} in label names. By default constructors and destructors in
-G++ have @samp{$} in the identifiers. If this macro is defined,
-@samp{.} is used instead.
-@end defmac
-
-@defmac NO_DOT_IN_LABEL
-Define this macro if the assembler does not accept the character
-@samp{.} in label names. By default constructors and destructors in G++
-have names that use @samp{.}. If this macro is defined, these names
-are rewritten to avoid @samp{.}.
-@end defmac
-
-@defmac TYPE_ASM_OP
-A C string containing the appropriate assembler directive to specify the
-type of a symbol, without any arguments. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"\t.type\t"}; on other
-systems, the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definition of
-@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
-custom definition of this macro, or if you do not need explicit symbol
-types at all, do not define this macro.
-@end defmac
-
-@defmac TYPE_OPERAND_FMT
-A C string which specifies (using @code{printf} syntax) the format of
-the second operand to @code{TYPE_ASM_OP}. On systems that use ELF, the
-default (in @file{config/elfos.h}) is @samp{"@@%s"}; on other systems,
-the default is not to define this macro.
-
-Define this macro only if it is correct to use the default definition of
-@code{ASM_OUTPUT_TYPE_DIRECTIVE} for your system. If you need your own
-custom definition of this macro, or if you do not need explicit symbol
-types at all, do not define this macro.
-@end defmac
-
-@defmac ASM_OUTPUT_TYPE_DIRECTIVE (@var{stream}, @var{type})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a directive telling the assembler that the type of the
-symbol @var{name} is @var{type}. @var{type} is a C string; currently,
-that string is always either @samp{"function"} or @samp{"object"}, but
-you should not count on this.
-
-If you define @code{TYPE_ASM_OP} and @code{TYPE_OPERAND_FMT}, a default
-definition of this macro is provided.
-@end defmac
-
-@defmac ASM_DECLARE_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of a
-function which is being defined. This macro is responsible for
-outputting the label definition (perhaps using
-@code{ASM_OUTPUT_FUNCTION_LABEL}). The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the function name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_FUNCTION_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the size of a function
-which is being defined. The argument @var{name} is the name of the
-function. The argument @var{decl} is the @code{FUNCTION_DECL} tree node
-representing the function.
-
-If this macro is not defined, then the function size is not defined.
-
-You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_COLD_FUNCTION_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of a
-cold function partition which is being defined. This macro is responsible
-for outputting the label definition (perhaps using
-@code{ASM_OUTPUT_FUNCTION_LABEL}). The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the cold partition name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_COLD_FUNCTION_SIZE (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the size of a cold function
-partition which is being defined. The argument @var{name} is the name of the
-cold partition of the function. The argument @var{decl} is the
-@code{FUNCTION_DECL} tree node representing the function.
-
-If this macro is not defined, then the partition size is not defined.
-
-You may wish to use @code{ASM_OUTPUT_MEASURED_SIZE} in the definition
-of this macro.
-@end defmac
-
-@defmac ASM_DECLARE_OBJECT_NAME (@var{stream}, @var{name}, @var{decl})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name @var{name} of an
-initialized variable which is being defined. This macro must output the
-label definition (perhaps using @code{ASM_OUTPUT_LABEL}). The argument
-@var{decl} is the @code{VAR_DECL} tree node representing the variable.
-
-If this macro is not defined, then the variable name is defined in the
-usual manner as a label (by means of @code{ASM_OUTPUT_LABEL}).
-
-You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} and/or
-@code{ASM_OUTPUT_SIZE_DIRECTIVE} in the definition of this macro.
-@end defmac
-
-@hook TARGET_ASM_DECLARE_CONSTANT_NAME
-
-@defmac ASM_DECLARE_REGISTER_GLOBAL (@var{stream}, @var{decl}, @var{regno}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for claiming a register @var{regno}
-for a global variable @var{decl} with name @var{name}.
-
-If you don't define this macro, that is equivalent to defining it to do
-nothing.
-@end defmac
-
-@defmac ASM_FINISH_DECLARE_OBJECT (@var{stream}, @var{decl}, @var{toplevel}, @var{atend})
-A C statement (sans semicolon) to finish up declaring a variable name
-once the compiler has processed its initializer fully and thus has had a
-chance to determine the size of an array when controlled by an
-initializer. This is used on systems where it's necessary to declare
-something about the size of the object.
-
-If you don't define this macro, that is equivalent to defining it to do
-nothing.
-
-You may wish to use @code{ASM_OUTPUT_SIZE_DIRECTIVE} and/or
-@code{ASM_OUTPUT_MEASURED_SIZE} in the definition of this macro.
-@end defmac
-
-@hook TARGET_ASM_GLOBALIZE_LABEL
-
-@hook TARGET_ASM_GLOBALIZE_DECL_NAME
-
-@hook TARGET_ASM_ASSEMBLE_UNDEFINED_DECL
-
-@defmac ASM_WEAKEN_LABEL (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} some commands that will make the label @var{name} weak;
-that is, available for reference from other files but only used if
-no other definition is available. Use the expression
-@code{assemble_name (@var{stream}, @var{name})} to output the name
-itself; before and after that, output the additional assembler syntax
-for making that name weak, and a newline.
-
-If you don't define this macro or @code{ASM_WEAKEN_DECL}, GCC will not
-support weak symbols and you should not define the @code{SUPPORTS_WEAK}
-macro.
-@end defmac
-
-@defmac ASM_WEAKEN_DECL (@var{stream}, @var{decl}, @var{name}, @var{value})
-Combines (and replaces) the function of @code{ASM_WEAKEN_LABEL} and
-@code{ASM_OUTPUT_WEAK_ALIAS}, allowing access to the associated function
-or variable decl. If @var{value} is not @code{NULL}, this C statement
-should output to the stdio stream @var{stream} assembler code which
-defines (equates) the weak symbol @var{name} to have the value
-@var{value}. If @var{value} is @code{NULL}, it should output commands
-to make @var{name} weak.
-@end defmac
-
-@defmac ASM_OUTPUT_WEAKREF (@var{stream}, @var{decl}, @var{name}, @var{value})
-Outputs a directive that enables @var{name} to be used to refer to
-symbol @var{value} with weak-symbol semantics. @code{decl} is the
-declaration of @code{name}.
-@end defmac
-
-@defmac SUPPORTS_WEAK
-A preprocessor constant expression which evaluates to true if the target
-supports weak symbols.
-
-If you don't define this macro, @file{defaults.h} provides a default
-definition. If either @code{ASM_WEAKEN_LABEL} or @code{ASM_WEAKEN_DECL}
-is defined, the default definition is @samp{1}; otherwise, it is @samp{0}.
-@end defmac
-
-@defmac TARGET_SUPPORTS_WEAK
-A C expression which evaluates to true if the target supports weak symbols.
-
-If you don't define this macro, @file{defaults.h} provides a default
-definition. The default definition is @samp{(SUPPORTS_WEAK)}. Define
-this macro if you want to control weak symbol support with a compiler
-flag such as @option{-melf}.
-@end defmac
-
-@defmac MAKE_DECL_ONE_ONLY (@var{decl})
-A C statement (sans semicolon) to mark @var{decl} to be emitted as a
-public symbol such that extra copies in multiple translation units will
-be discarded by the linker. Define this macro if your object file
-format provides support for this concept, such as the @samp{COMDAT}
-section flags in the Microsoft Windows PE/COFF format, and this support
-requires changes to @var{decl}, such as putting it in a separate section.
-@end defmac
-
-@defmac SUPPORTS_ONE_ONLY
-A C expression which evaluates to true if the target supports one-only
-semantics.
-
-If you don't define this macro, @file{varasm.cc} provides a default
-definition. If @code{MAKE_DECL_ONE_ONLY} is defined, the default
-definition is @samp{1}; otherwise, it is @samp{0}. Define this macro if
-you want to control one-only symbol support with a compiler flag, or if
-setting the @code{DECL_ONE_ONLY} flag is enough to mark a declaration to
-be emitted as one-only.
-@end defmac
-
-@hook TARGET_ASM_ASSEMBLE_VISIBILITY
-
-@defmac TARGET_WEAK_NOT_IN_ARCHIVE_TOC
-A C expression that evaluates to true if the target's linker expects
-that weak symbols do not appear in a static archive's table of contents.
-The default is @code{0}.
-
-Leaving weak symbols out of an archive's table of contents means that,
-if a symbol will only have a definition in one translation unit and
-will have undefined references from other translation units, that
-symbol should not be weak. Defining this macro to be nonzero will
-thus have the effect that certain symbols that would normally be weak
-(explicit template instantiations, and vtables for polymorphic classes
-with noninline key methods) will instead be nonweak.
-
-The C++ ABI requires this macro to be zero. Define this macro for
-targets where full C++ ABI compliance is impossible and where linker
-restrictions require weak symbols to be left out of a static archive's
-table of contents.
-@end defmac
-
-@defmac ASM_OUTPUT_EXTERNAL (@var{stream}, @var{decl}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} any text necessary for declaring the name of an external
-symbol named @var{name} which is referenced in this compilation but
-not defined. The value of @var{decl} is the tree node for the
-declaration.
-
-This macro need not be defined if it does not need to output anything.
-The GNU assembler and most Unix assemblers don't require anything.
-@end defmac
-
-@hook TARGET_ASM_EXTERNAL_LIBCALL
-
-@hook TARGET_ASM_MARK_DECL_PRESERVED
-
-@defmac ASM_OUTPUT_LABELREF (@var{stream}, @var{name})
-A C statement (sans semicolon) to output to the stdio stream
-@var{stream} a reference in assembler syntax to a label named
-@var{name}. This should add @samp{_} to the front of the name, if that
-is customary on your operating system, as it is in most Berkeley Unix
-systems. This macro is used in @code{assemble_name}.
-@end defmac
-
-@hook TARGET_MANGLE_ASSEMBLER_NAME
-
-@defmac ASM_OUTPUT_SYMBOL_REF (@var{stream}, @var{sym})
-A C statement (sans semicolon) to output a reference to
-@code{SYMBOL_REF} @var{sym}. If not defined, @code{assemble_name}
-will be used to output the name of the symbol. This macro may be used
-to modify the way a symbol is referenced depending on information
-encoded by @code{TARGET_ENCODE_SECTION_INFO}.
-@end defmac
-
-@defmac ASM_OUTPUT_LABEL_REF (@var{stream}, @var{buf})
-A C statement (sans semicolon) to output a reference to @var{buf}, the
-result of @code{ASM_GENERATE_INTERNAL_LABEL}. If not defined,
-@code{assemble_name} will be used to output the name of the symbol.
-This macro is not used by @code{output_asm_label}, or the @code{%l}
-specifier that calls it; the intention is that this macro should be set
-when it is necessary to output a label differently when its address is
-being taken.
-@end defmac
-
-@hook TARGET_ASM_INTERNAL_LABEL
-
-@defmac ASM_OUTPUT_DEBUG_LABEL (@var{stream}, @var{prefix}, @var{num})
-A C statement to output to the stdio stream @var{stream} a debug info
-label whose name is made from the string @var{prefix} and the number
-@var{num}. This is useful for VLIW targets, where debug info labels
-may need to be treated differently than branch target labels. On some
-systems, branch target labels must be at the beginning of instruction
-bundles, but debug info labels can occur in the middle of instruction
-bundles.
-
-If this macro is not defined, then @code{(*targetm.asm_out.internal_label)} will be
-used.
-@end defmac
-
-@defmac ASM_GENERATE_INTERNAL_LABEL (@var{string}, @var{prefix}, @var{num})
-A C statement to store into the string @var{string} a label whose name
-is made from the string @var{prefix} and the number @var{num}.
-
-This string, when output subsequently by @code{assemble_name}, should
-produce the output that @code{(*targetm.asm_out.internal_label)} would produce
-with the same @var{prefix} and @var{num}.
-
-If the string begins with @samp{*}, then @code{assemble_name} will
-output the rest of the string unchanged. It is often convenient for
-@code{ASM_GENERATE_INTERNAL_LABEL} to use @samp{*} in this way. If the
-string doesn't start with @samp{*}, then @code{ASM_OUTPUT_LABELREF} gets
-to output the string, and may change it. (Of course,
-@code{ASM_OUTPUT_LABELREF} is also part of your machine description, so
-you should know what it does on your machine.)
-@end defmac
-
-@defmac ASM_FORMAT_PRIVATE_NAME (@var{outvar}, @var{name}, @var{number})
-A C expression to assign to @var{outvar} (which is a variable of type
-@code{char *}) a newly allocated string made from the string
-@var{name} and the number @var{number}, with some suitable punctuation
-added. Use @code{alloca} to get space for the string.
-
-The string will be used as an argument to @code{ASM_OUTPUT_LABELREF} to
-produce an assembler label for an internal static variable whose name is
-@var{name}. Therefore, the string must be such as to result in valid
-assembler code. The argument @var{number} is different each time this
-macro is executed; it prevents conflicts between similarly-named
-internal static variables in different scopes.
-
-Ideally this string should not be a valid C identifier, to prevent any
-conflict with the user's own symbols. Most assemblers allow periods
-or percent signs in assembler symbols; putting at least one of these
-between the name and the number will suffice.
-
-If this macro is not defined, a default definition will be provided
-which is correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_DEF (@var{stream}, @var{name}, @var{value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the symbol @var{name} to have the value @var{value}.
-
-@findex SET_ASM_OP
-If @code{SET_ASM_OP} is defined, a default definition is provided which is
-correct for most systems.
-@end defmac
-
-@defmac ASM_OUTPUT_DEF_FROM_DECLS (@var{stream}, @var{decl_of_name}, @var{decl_of_value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the symbol whose tree node is @var{decl_of_name}
-to have the value of the tree node @var{decl_of_value}. This macro will
-be used in preference to @samp{ASM_OUTPUT_DEF} if it is defined and if
-the tree nodes are available.
-
-@findex SET_ASM_OP
-If @code{SET_ASM_OP} is defined, a default definition is provided which is
-correct for most systems.
-@end defmac
-
-@defmac TARGET_DEFERRED_OUTPUT_DEFS (@var{decl_of_name}, @var{decl_of_value})
-A C statement that evaluates to true if the assembler code which defines
-(equates) the symbol whose tree node is @var{decl_of_name} to have the value
-of the tree node @var{decl_of_value} should be emitted near the end of the
-current compilation unit. The default is to not defer output of defines.
-This macro affects defines output by @samp{ASM_OUTPUT_DEF} and
-@samp{ASM_OUTPUT_DEF_FROM_DECLS}.
-@end defmac
-
-@defmac ASM_OUTPUT_WEAK_ALIAS (@var{stream}, @var{name}, @var{value})
-A C statement to output to the stdio stream @var{stream} assembler code
-which defines (equates) the weak symbol @var{name} to have the value
-@var{value}. If @var{value} is @code{NULL}, it defines @var{name} as
-an undefined weak symbol.
-
-Define this macro if the target only supports weak aliases; define
-@code{ASM_OUTPUT_DEF} instead if possible.
-@end defmac
-
-@defmac OBJC_GEN_METHOD_LABEL (@var{buf}, @var{is_inst}, @var{class_name}, @var{cat_name}, @var{sel_name})
-Define this macro to override the default assembler names used for
-Objective-C methods.
-
-The default name is a unique method number followed by the name of the
-class (e.g.@: @samp{_1_Foo}). For methods in categories, the name of
-the category is also included in the assembler name (e.g.@:
-@samp{_1_Foo_Bar}).
-
-These names are safe on most systems, but make debugging difficult since
-the method's selector is not present in the name. Therefore, particular
-systems define other ways of computing names.
-
-@var{buf} is an expression of type @code{char *} which gives you a
-buffer in which to store the name; its length is as long as
-@var{class_name}, @var{cat_name} and @var{sel_name} put together, plus
-50 characters extra.
-
-The argument @var{is_inst} specifies whether the method is an instance
-method or a class method; @var{class_name} is the name of the class;
-@var{cat_name} is the name of the category (or @code{NULL} if the method is not
-in a category); and @var{sel_name} is the name of the selector.
-
-On systems where the assembler can handle quoted names, you can use this
-macro to provide more human-readable names.
-@end defmac
-
-@node Initialization
-@subsection How Initialization Functions Are Handled
-@cindex initialization routines
-@cindex termination routines
-@cindex constructors, output of
-@cindex destructors, output of
-
-The compiled code for certain languages includes @dfn{constructors}
-(also called @dfn{initialization routines})---functions to initialize
-data in the program when the program is started. These functions need
-to be called before the program is ``started''---that is to say, before
-@code{main} is called.
-
-Compiling some languages generates @dfn{destructors} (also called
-@dfn{termination routines}) that should be called when the program
-terminates.
-
-To make the initialization and termination functions work, the compiler
-must output something in the assembler code to cause those functions to
-be called at the appropriate time. When you port the compiler to a new
-system, you need to specify how to do this.
-
-There are two major ways that GCC currently supports the execution of
-initialization and termination functions. Each way has two variants.
-Much of the structure is common to all four variations.
-
-@findex __CTOR_LIST__
-@findex __DTOR_LIST__
-The linker must build two lists of these functions---a list of
-initialization functions, called @code{__CTOR_LIST__}, and a list of
-termination functions, called @code{__DTOR_LIST__}.
-
-Each list always begins with an ignored function pointer (which may hold
-0, @minus{}1, or a count of the function pointers after it, depending on
-the environment). This is followed by a series of zero or more function
-pointers to constructors (or destructors), followed by a function
-pointer containing zero.
-
-Depending on the operating system and its executable file format, either
-@file{crtstuff.c} or @file{libgcc2.c} traverses these lists at startup
-time and exit time. Constructors are called in reverse order of the
-list; destructors in forward order.
-
-The best way to handle static constructors works only for object file
-formats which provide arbitrarily-named sections. A section is set
-aside for a list of constructors, and another for a list of destructors.
-Traditionally these are called @samp{.ctors} and @samp{.dtors}. Each
-object file that defines an initialization function also puts a word in
-the constructor section to point to that function. The linker
-accumulates all these words into one contiguous @samp{.ctors} section.
-Termination functions are handled similarly.
-
-This method will be chosen as the default by @file{target-def.h} if
-@code{TARGET_ASM_NAMED_SECTION} is defined. A target that does not
-support arbitrary sections, but does support special designated
-constructor and destructor sections may define @code{CTORS_SECTION_ASM_OP}
-and @code{DTORS_SECTION_ASM_OP} to achieve the same effect.
-
-When arbitrary sections are available, there are two variants, depending
-upon how the code in @file{crtstuff.c} is called. On systems that
-support a @dfn{.init} section which is executed at program startup,
-parts of @file{crtstuff.c} are compiled into that section. The
-program is linked by the @command{gcc} driver like this:
-
-@smallexample
-ld -o @var{output_file} crti.o crtbegin.o @dots{} -lgcc crtend.o crtn.o
-@end smallexample
-
-The prologue of a function (@code{__init}) appears in the @code{.init}
-section of @file{crti.o}; the epilogue appears in @file{crtn.o}. Likewise
-for the function @code{__fini} in the @dfn{.fini} section. Normally these
-files are provided by the operating system or by the GNU C library, but
-are provided by GCC for a few targets.
-
-The objects @file{crtbegin.o} and @file{crtend.o} are (for most targets)
-compiled from @file{crtstuff.c}. They contain, among other things, code
-fragments within the @code{.init} and @code{.fini} sections that branch
-to routines in the @code{.text} section. The linker will pull all parts
-of a section together, which results in a complete @code{__init} function
-that invokes the routines we need at startup.
-
-To use this variant, you must define the @code{INIT_SECTION_ASM_OP}
-macro properly.
-
-If no init section is available, when GCC compiles any function called
-@code{main} (or more accurately, any function designated as a program
-entry point by the language front end calling @code{expand_main_function}),
-it inserts a procedure call to @code{__main} as the first executable code
-after the function prologue. The @code{__main} function is defined
-in @file{libgcc2.c} and runs the global constructors.
-
-In file formats that don't support arbitrary sections, there are again
-two variants. In the simplest variant, the GNU linker (GNU @code{ld})
-and an `a.out' format must be used. In this case,
-@code{TARGET_ASM_CONSTRUCTOR} is defined to produce a @code{.stabs}
-entry of type @samp{N_SETT}, referencing the name @code{__CTOR_LIST__},
-and with the address of the void function containing the initialization
-code as its value. The GNU linker recognizes this as a request to add
-the value to a @dfn{set}; the values are accumulated, and are eventually
-placed in the executable as a vector in the format described above, with
-a leading (ignored) count and a trailing zero element.
-@code{TARGET_ASM_DESTRUCTOR} is handled similarly. Since no init
-section is available, the absence of @code{INIT_SECTION_ASM_OP} causes
-the compilation of @code{main} to call @code{__main} as above, starting
-the initialization process.
-
-The last variant uses neither arbitrary sections nor the GNU linker.
-This is preferable when you want to do dynamic linking and when using
-file formats which the GNU linker does not support, such as `ECOFF'@. In
-this case, @code{TARGET_HAVE_CTORS_DTORS} is false, initialization and
-termination functions are recognized simply by their names. This requires
-an extra program in the linkage step, called @command{collect2}. This program
-pretends to be the linker, for use with GCC; it does its job by running
-the ordinary linker, but also arranges to include the vectors of
-initialization and termination functions. These functions are called
-via @code{__main} as described above. In order to use this method,
-@code{use_collect2} must be defined in the target in @file{config.gcc}.
-
-@ifinfo
-The following section describes the specific macros that control and
-customize the handling of initialization and termination functions.
-@end ifinfo
-
-@node Macros for Initialization
-@subsection Macros Controlling Initialization Routines
-
-Here are the macros that control how the compiler handles initialization
-and termination functions:
-
-@defmac INIT_SECTION_ASM_OP
-If defined, a C string constant, including spacing, for the assembler
-operation to identify the following data as initialization code. If not
-defined, GCC will assume such a section does not exist. When you are
-using special sections for initialization and termination functions, this
-macro also controls how @file{crtstuff.c} and @file{libgcc2.c} arrange to
-run the initialization functions.
-@end defmac
-
-@defmac HAS_INIT_SECTION
-If defined, @code{main} will not call @code{__main} as described above.
-This macro should be defined for systems that control start-up code
-on a symbol-by-symbol basis, such as OSF/1, and should not
-be defined explicitly for systems that support @code{INIT_SECTION_ASM_OP}.
-@end defmac
-
-@defmac LD_INIT_SWITCH
-If defined, a C string constant for a switch that tells the linker that
-the following symbol is an initialization routine.
-@end defmac
-
-@defmac LD_FINI_SWITCH
-If defined, a C string constant for a switch that tells the linker that
-the following symbol is a finalization routine.
-@end defmac
-
-@defmac COLLECT_SHARED_INIT_FUNC (@var{stream}, @var{func})
-If defined, a C statement that will write a function that can be
-automatically called when a shared library is loaded. The function
-should call @var{func}, which takes no arguments. If not defined, and
-the object format requires an explicit initialization function, then a
-function called @code{_GLOBAL__DI} will be generated.
-
-This function and the following one are used by collect2 when linking a
-shared library that needs constructors or destructors, or has DWARF2
-exception tables embedded in the code.
-@end defmac
-
-@defmac COLLECT_SHARED_FINI_FUNC (@var{stream}, @var{func})
-If defined, a C statement that will write a function that can be
-automatically called when a shared library is unloaded. The function
-should call @var{func}, which takes no arguments. If not defined, and
-the object format requires an explicit finalization function, then a
-function called @code{_GLOBAL__DD} will be generated.
-@end defmac
-
-@defmac INVOKE__main
-If defined, @code{main} will call @code{__main} despite the presence of
-@code{INIT_SECTION_ASM_OP}. This macro should be defined for systems
-where the init section is not actually run automatically, but is still
-useful for collecting the lists of constructors and destructors.
-@end defmac
-
-@defmac SUPPORTS_INIT_PRIORITY
-If nonzero, the C++ @code{init_priority} attribute is supported and the
-compiler should emit instructions to control the order of initialization
-of objects. If zero, the compiler will issue an error message upon
-encountering an @code{init_priority} attribute.
-@end defmac
-
-@hook TARGET_HAVE_CTORS_DTORS
-
-@hook TARGET_DTORS_FROM_CXA_ATEXIT
-
-@hook TARGET_ASM_CONSTRUCTOR
-
-@hook TARGET_ASM_DESTRUCTOR
-
-If @code{TARGET_HAVE_CTORS_DTORS} is true, the initialization routine
-generated for the generated object file will have static linkage.
-
-If your system uses @command{collect2} as the means of processing
-constructors, then that program normally uses @command{nm} to scan
-an object file for constructor functions to be called.
-
-On certain kinds of systems, you can define this macro to make
-@command{collect2} work faster (and, in some cases, make it work at all):
-
-@defmac OBJECT_FORMAT_COFF
-Define this macro if the system uses COFF (Common Object File Format)
-object files, so that @command{collect2} can assume this format and scan
-object files directly for dynamic constructor/destructor functions.
-
-This macro is effective only in a native compiler; @command{collect2} as
-part of a cross compiler always uses @command{nm} for the target machine.
-@end defmac
-
-@defmac REAL_NM_FILE_NAME
-Define this macro as a C string constant containing the file name to use
-to execute @command{nm}. The default is to search the path normally for
-@command{nm}.
-@end defmac
-
-@defmac NM_FLAGS
-@command{collect2} calls @command{nm} to scan object files for static
-constructors and destructors and LTO info. By default, @option{-n} is
-passed. Define @code{NM_FLAGS} to a C string constant if other options
-are needed to get the same output format as GNU @command{nm -n}
-produces.
-@end defmac
-
-If your system supports shared libraries and has a program to list the
-dynamic dependencies of a given library or executable, you can define
-these macros to enable support for running initialization and
-termination functions in shared libraries:
-
-@defmac LDD_SUFFIX
-Define this macro to a C string constant containing the name of the program
-which lists dynamic dependencies, like @command{ldd} under SunOS 4.
-@end defmac
-
-@defmac PARSE_LDD_OUTPUT (@var{ptr})
-Define this macro to be C code that extracts filenames from the output
-of the program denoted by @code{LDD_SUFFIX}. @var{ptr} is a variable
-of type @code{char *} that points to the beginning of a line of output
-from @code{LDD_SUFFIX}. If the line lists a dynamic dependency, the
-code must advance @var{ptr} to the beginning of the filename on that
-line. Otherwise, it must set @var{ptr} to @code{NULL}.
-@end defmac
-
-@defmac SHLIB_SUFFIX
-Define this macro to a C string constant containing the default shared
-library extension of the target (e.g., @samp{".so"}). @command{collect2}
-strips version information after this suffix when generating global
-constructor and destructor names. This define is only needed on targets
-that use @command{collect2} to process constructors and destructors.
-@end defmac
-
-@node Instruction Output
-@subsection Output of Assembler Instructions
-
-@c prevent bad page break with this line
-This describes assembler instruction output.
-
-@defmac REGISTER_NAMES
-A C initializer containing the assembler's names for the machine
-registers, each one as a C string constant. This is what translates
-register numbers in the compiler into assembler language.
-@end defmac
-
-@defmac ADDITIONAL_REGISTER_NAMES
-If defined, a C initializer for an array of structures containing a name
-and a register number. This macro defines additional names for hard
-registers, thus allowing the @code{asm} option in declarations to refer
-to registers using alternate names.
-@end defmac
-
-@defmac OVERLAPPING_REGISTER_NAMES
-If defined, a C initializer for an array of structures containing a
-name, a register number and a count of the number of consecutive
-machine registers the name overlaps. This macro defines additional
-names for hard registers, thus allowing the @code{asm} option in
-declarations to refer to registers using alternate names. Unlike
-@code{ADDITIONAL_REGISTER_NAMES}, this macro should be used when the
-register name implies multiple underlying registers.
-
-This macro should be used when it is important that a clobber in an
-@code{asm} statement clobbers all the underlying values implied by the
-register name. For example, on ARM, clobbering the double-precision
-VFP register ``d0'' implies clobbering both single-precision registers
-``s0'' and ``s1''.
-@end defmac
-
-@defmac ASM_OUTPUT_OPCODE (@var{stream}, @var{ptr})
-Define this macro if you are using an unusual assembler that
-requires different names for the machine instructions.
-
-The definition is a C statement or statements which output an
-assembler instruction opcode to the stdio stream @var{stream}. The
-macro-operand @var{ptr} is a variable of type @code{char *} which
-points to the opcode name in its ``internal'' form---the form that is
-written in the machine description. The definition should output the
-opcode name to @var{stream}, performing any translation you desire, and
-increment the variable @var{ptr} to point at the end of the opcode
-so that it will not be output twice.
-
-In fact, your macro definition may process less than the entire opcode
-name, or more than the opcode name; but if you want to process text
-that includes @samp{%}-sequences to substitute operands, you must take
-care of the substitution yourself. Just be sure to increment
-@var{ptr} over whatever text should not be output normally.
-
-@findex recog_data.operand
-If you need to look at the operand values, they can be found as the
-elements of @code{recog_data.operand}.
-
-If the macro definition does nothing, the instruction is output
-in the usual way.
-@end defmac
-
-@defmac FINAL_PRESCAN_INSN (@var{insn}, @var{opvec}, @var{noperands})
-If defined, a C statement to be executed just prior to the output of
-assembler code for @var{insn}, to modify the extracted operands so
-they will be output differently.
-
-Here the argument @var{opvec} is the vector containing the operands
-extracted from @var{insn}, and @var{noperands} is the number of
-elements of the vector which contain meaningful data for this insn.
-The contents of this vector are what will be used to convert the insn
-template into assembler code, so you can change the assembler output
-by changing the contents of the vector.
-
-This macro is useful when various assembler syntaxes share a single
-file of instruction patterns; by defining this macro differently, you
-can cause a large class of instructions to be output differently (such
-as with rearranged operands). Naturally, variations in assembler
-syntax affecting individual insn patterns ought to be handled by
-writing conditional output routines in those patterns.
-
-If this macro is not defined, it is equivalent to a null statement.
-@end defmac
-
-@hook TARGET_ASM_FINAL_POSTSCAN_INSN
-
-@defmac PRINT_OPERAND (@var{stream}, @var{x}, @var{code})
-A C compound statement to output to stdio stream @var{stream} the
-assembler syntax for an instruction operand @var{x}. @var{x} is an
-RTL expression.
-
-@var{code} is a value that can be used to specify one of several ways
-of printing the operand. It is used when identical operands must be
-printed differently depending on the context. @var{code} comes from
-the @samp{%} specification that was used to request printing of the
-operand. If the specification was just @samp{%@var{digit}} then
-@var{code} is 0; if the specification was @samp{%@var{ltr}
-@var{digit}} then @var{code} is the ASCII code for @var{ltr}.
-
-@findex reg_names
-If @var{x} is a register, this macro should print the register's name.
-The names can be found in an array @code{reg_names} whose type is
-@code{char *[]}. @code{reg_names} is initialized from
-@code{REGISTER_NAMES}.
-
-When the machine description has a specification @samp{%@var{punct}}
-(a @samp{%} followed by a punctuation character), this macro is called
-with a null pointer for @var{x} and the punctuation character for
-@var{code}.
-@end defmac
-
-@defmac PRINT_OPERAND_PUNCT_VALID_P (@var{code})
-A C expression which evaluates to true if @var{code} is a valid
-punctuation character for use in the @code{PRINT_OPERAND} macro. If
-@code{PRINT_OPERAND_PUNCT_VALID_P} is not defined, it means that no
-punctuation characters (except for the standard one, @samp{%}) are used
-in this way.
-@end defmac
-
-@defmac PRINT_OPERAND_ADDRESS (@var{stream}, @var{x})
-A C compound statement to output to stdio stream @var{stream} the
-assembler syntax for an instruction operand that is a memory reference
-whose address is @var{x}. @var{x} is an RTL expression.
-
-@cindex @code{TARGET_ENCODE_SECTION_INFO} usage
-On some machines, the syntax for a symbolic address depends on the
-section that the address refers to. On these machines, define the hook
-@code{TARGET_ENCODE_SECTION_INFO} to store the information into the
-@code{symbol_ref}, and then check for it here. @xref{Assembler
-Format}.
-@end defmac
-
-@findex dbr_sequence_length
-@defmac DBR_OUTPUT_SEQEND (@var{file})
-A C statement, to be executed after all slot-filler instructions have
-been output. If necessary, call @code{dbr_sequence_length} to
-determine the number of slots filled in a sequence (zero if not
-currently outputting a sequence), to decide how many no-ops to output,
-or whatever.
-
-Don't define this macro if it has nothing to do, but it is helpful in
-reading assembly output if the extent of the delay sequence is made
-explicit (e.g.@: with white space).
-@end defmac
-
-@findex final_sequence
-Note that output routines for instructions with delay slots must be
-prepared to deal with not being output as part of a sequence
-(i.e.@: when the scheduling pass is not run, or when no slot fillers could be
-found.) The variable @code{final_sequence} is null when not
-processing a sequence, otherwise it contains the @code{sequence} rtx
-being output.
-
-@findex asm_fprintf
-@defmac REGISTER_PREFIX
-@defmacx LOCAL_LABEL_PREFIX
-@defmacx USER_LABEL_PREFIX
-@defmacx IMMEDIATE_PREFIX
-If defined, C string expressions to be used for the @samp{%R}, @samp{%L},
-@samp{%U}, and @samp{%I} options of @code{asm_fprintf} (see
-@file{final.cc}). These are useful when a single @file{md} file must
-support multiple assembler formats. In that case, the various @file{tm.h}
-files can define these macros differently.
-@end defmac
-
-@defmac ASM_FPRINTF_EXTENSIONS (@var{file}, @var{argptr}, @var{format})
-If defined this macro should expand to a series of @code{case}
-statements which will be parsed inside the @code{switch} statement of
-the @code{asm_fprintf} function. This allows targets to define extra
-printf formats which may useful when generating their assembler
-statements. Note that uppercase letters are reserved for future
-generic extensions to asm_fprintf, and so are not available to target
-specific code. The output file is given by the parameter @var{file}.
-The varargs input pointer is @var{argptr} and the rest of the format
-string, starting the character after the one that is being switched
-upon, is pointed to by @var{format}.
-@end defmac
-
-@defmac ASSEMBLER_DIALECT
-If your target supports multiple dialects of assembler language (such as
-different opcodes), define this macro as a C expression that gives the
-numeric index of the assembler language dialect to use, with zero as the
-first variant.
-
-If this macro is defined, you may use constructs of the form
-@smallexample
-@samp{@{option0|option1|option2@dots{}@}}
-@end smallexample
-@noindent
-in the output templates of patterns (@pxref{Output Template}) or in the
-first argument of @code{asm_fprintf}. This construct outputs
-@samp{option0}, @samp{option1}, @samp{option2}, etc., if the value of
-@code{ASSEMBLER_DIALECT} is zero, one, two, etc. Any special characters
-within these strings retain their usual meaning. If there are fewer
-alternatives within the braces than the value of
-@code{ASSEMBLER_DIALECT}, the construct outputs nothing. If it's needed
-to print curly braces or @samp{|} character in assembler output directly,
-@samp{%@{}, @samp{%@}} and @samp{%|} can be used.
-
-If you do not define this macro, the characters @samp{@{}, @samp{|} and
-@samp{@}} do not have any special meaning when used in templates or
-operands to @code{asm_fprintf}.
-
-Define the macros @code{REGISTER_PREFIX}, @code{LOCAL_LABEL_PREFIX},
-@code{USER_LABEL_PREFIX} and @code{IMMEDIATE_PREFIX} if you can express
-the variations in assembler language syntax with that mechanism. Define
-@code{ASSEMBLER_DIALECT} and use the @samp{@{option0|option1@}} syntax
-if the syntax variant are larger and involve such things as different
-opcodes or operand order.
-@end defmac
-
-@defmac ASM_OUTPUT_REG_PUSH (@var{stream}, @var{regno})
-A C expression to output to @var{stream} some assembler code
-which will push hard register number @var{regno} onto the stack.
-The code need not be optimal, since this macro is used only when
-profiling.
-@end defmac
-
-@defmac ASM_OUTPUT_REG_POP (@var{stream}, @var{regno})
-A C expression to output to @var{stream} some assembler code
-which will pop hard register number @var{regno} off of the stack.
-The code need not be optimal, since this macro is used only when
-profiling.
-@end defmac
-
-@node Dispatch Tables
-@subsection Output of Dispatch Tables
-
-@c prevent bad page break with this line
-This concerns dispatch tables.
-
-@cindex dispatch table
-@defmac ASM_OUTPUT_ADDR_DIFF_ELT (@var{stream}, @var{body}, @var{value}, @var{rel})
-A C statement to output to the stdio stream @var{stream} an assembler
-pseudo-instruction to generate a difference between two labels.
-@var{value} and @var{rel} are the numbers of two internal labels. The
-definitions of these labels are output using
-@code{(*targetm.asm_out.internal_label)}, and they must be printed in the same
-way here. For example,
-
-@smallexample
-fprintf (@var{stream}, "\t.word L%d-L%d\n",
- @var{value}, @var{rel})
-@end smallexample
-
-You must provide this macro on machines where the addresses in a
-dispatch table are relative to the table's own address. If defined, GCC
-will also use this macro on all machines when producing PIC@.
-@var{body} is the body of the @code{ADDR_DIFF_VEC}; it is provided so that the
-mode and flags can be read.
-@end defmac
-
-@defmac ASM_OUTPUT_ADDR_VEC_ELT (@var{stream}, @var{value})
-This macro should be provided on machines where the addresses
-in a dispatch table are absolute.
-
-The definition should be a C statement to output to the stdio stream
-@var{stream} an assembler pseudo-instruction to generate a reference to
-a label. @var{value} is the number of an internal label whose
-definition is output using @code{(*targetm.asm_out.internal_label)}.
-For example,
-
-@smallexample
-fprintf (@var{stream}, "\t.word L%d\n", @var{value})
-@end smallexample
-@end defmac
-
-@defmac ASM_OUTPUT_CASE_LABEL (@var{stream}, @var{prefix}, @var{num}, @var{table})
-Define this if the label before a jump-table needs to be output
-specially. The first three arguments are the same as for
-@code{(*targetm.asm_out.internal_label)}; the fourth argument is the
-jump-table which follows (a @code{jump_table_data} containing an
-@code{addr_vec} or @code{addr_diff_vec}).
-
-This feature is used on system V to output a @code{swbeg} statement
-for the table.
-
-If this macro is not defined, these labels are output with
-@code{(*targetm.asm_out.internal_label)}.
-@end defmac
-
-@defmac ASM_OUTPUT_CASE_END (@var{stream}, @var{num}, @var{table})
-Define this if something special must be output at the end of a
-jump-table. The definition should be a C statement to be executed
-after the assembler code for the table is written. It should write
-the appropriate code to stdio stream @var{stream}. The argument
-@var{table} is the jump-table insn, and @var{num} is the label-number
-of the preceding label.
-
-If this macro is not defined, nothing special is output at the end of
-the jump-table.
-@end defmac
-
-@hook TARGET_ASM_POST_CFI_STARTPROC
-
-@hook TARGET_ASM_EMIT_UNWIND_LABEL
-
-@hook TARGET_ASM_EMIT_EXCEPT_TABLE_LABEL
-
-@hook TARGET_ASM_EMIT_EXCEPT_PERSONALITY
-
-@hook TARGET_ASM_UNWIND_EMIT
-
-@hook TARGET_ASM_MAKE_EH_SYMBOL_INDIRECT
-
-@hook TARGET_ASM_UNWIND_EMIT_BEFORE_INSN
-
-@hook TARGET_ASM_SHOULD_RESTORE_CFA_STATE
-
-@node Exception Region Output
-@subsection Assembler Commands for Exception Regions
-
-@c prevent bad page break with this line
-
-This describes commands marking the start and the end of an exception
-region.
-
-@defmac EH_FRAME_SECTION_NAME
-If defined, a C string constant for the name of the section containing
-exception handling frame unwind information. If not defined, GCC will
-provide a default definition if the target supports named sections.
-@file{crtstuff.c} uses this macro to switch to the appropriate section.
-
-You should define this symbol if your target supports DWARF 2 frame
-unwind information and the default definition does not work.
-@end defmac
-
-@defmac EH_FRAME_THROUGH_COLLECT2
-If defined, DWARF 2 frame unwind information will identified by
-specially named labels. The collect2 process will locate these
-labels and generate code to register the frames.
-
-This might be necessary, for instance, if the system linker will not
-place the eh_frames in-between the sentinals from @file{crtstuff.c},
-or if the system linker does garbage collection and sections cannot
-be marked as not to be collected.
-@end defmac
-
-@defmac EH_TABLES_CAN_BE_READ_ONLY
-Define this macro to 1 if your target is such that no frame unwind
-information encoding used with non-PIC code will ever require a
-runtime relocation, but the linker may not support merging read-only
-and read-write sections into a single read-write section.
-@end defmac
-
-@defmac MASK_RETURN_ADDR
-An rtx used to mask the return address found via @code{RETURN_ADDR_RTX}, so
-that it does not contain any extraneous set bits in it.
-@end defmac
-
-@defmac DWARF2_UNWIND_INFO
-Define this macro to 0 if your target supports DWARF 2 frame unwind
-information, but it does not yet work with exception handling.
-Otherwise, if your target supports this information (if it defines
-@code{INCOMING_RETURN_ADDR_RTX} and @code{OBJECT_FORMAT_ELF}),
-GCC will provide a default definition of 1.
-@end defmac
-
-@hook TARGET_EXCEPT_UNWIND_INFO
-This hook defines the mechanism that will be used for exception handling
-by the target. If the target has ABI specified unwind tables, the hook
-should return @code{UI_TARGET}. If the target is to use the
-@code{setjmp}/@code{longjmp}-based exception handling scheme, the hook
-should return @code{UI_SJLJ}. If the target supports DWARF 2 frame unwind
-information, the hook should return @code{UI_DWARF2}.
-
-A target may, if exceptions are disabled, choose to return @code{UI_NONE}.
-This may end up simplifying other parts of target-specific code. The
-default implementation of this hook never returns @code{UI_NONE}.
-
-Note that the value returned by this hook should be constant. It should
-not depend on anything except the command-line switches described by
-@var{opts}. In particular, the
-setting @code{UI_SJLJ} must be fixed at compiler start-up as C pre-processor
-macros and builtin functions related to exception handling are set up
-depending on this setting.
-
-The default implementation of the hook first honors the
-@option{--enable-sjlj-exceptions} configure option, then
-@code{DWARF2_UNWIND_INFO}, and finally defaults to @code{UI_SJLJ}. If
-@code{DWARF2_UNWIND_INFO} depends on command-line options, the target
-must define this hook so that @var{opts} is used correctly.
-@end deftypefn
-
-@hook TARGET_UNWIND_TABLES_DEFAULT
-This variable should be set to @code{true} if the target ABI requires unwinding
-tables even when exceptions are not used. It must not be modified by
-command-line option processing.
-@end deftypevr
-
-@defmac DONT_USE_BUILTIN_SETJMP
-Define this macro to 1 if the @code{setjmp}/@code{longjmp}-based scheme
-should use the @code{setjmp}/@code{longjmp} functions from the C library
-instead of the @code{__builtin_setjmp}/@code{__builtin_longjmp} machinery.
-@end defmac
-
-@defmac JMP_BUF_SIZE
-This macro has no effect unless @code{DONT_USE_BUILTIN_SETJMP} is also
-defined. Define this macro if the default size of @code{jmp_buf} buffer
-for the @code{setjmp}/@code{longjmp}-based exception handling mechanism
-is not large enough, or if it is much too large.
-The default size is @code{FIRST_PSEUDO_REGISTER * sizeof(void *)}.
-@end defmac
-
-@defmac DWARF_CIE_DATA_ALIGNMENT
-This macro need only be defined if the target might save registers in the
-function prologue at an offset to the stack pointer that is not aligned to
-@code{UNITS_PER_WORD}. The definition should be the negative minimum
-alignment if @code{STACK_GROWS_DOWNWARD} is true, and the positive
-minimum alignment otherwise. @xref{DWARF}. Only applicable if
-the target supports DWARF 2 frame unwind information.
-@end defmac
-
-@hook TARGET_TERMINATE_DW2_EH_FRAME_INFO
-
-@hook TARGET_DWARF_REGISTER_SPAN
-
-@hook TARGET_DWARF_FRAME_REG_MODE
-
-@hook TARGET_INIT_DWARF_REG_SIZES_EXTRA
-
-@hook TARGET_ASM_TTYPE
-
-@hook TARGET_ARM_EABI_UNWINDER
-
-@node Alignment Output
-@subsection Assembler Commands for Alignment
-
-@c prevent bad page break with this line
-This describes commands for alignment.
-
-@defmac JUMP_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label}, which is
-a common destination of jumps and has no fallthru incoming edge.
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @var{align_jumps} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @var{align_jumps} in a @code{JUMP_ALIGN} implementation.
-@end defmac
-
-@defmac LABEL_ALIGN_AFTER_BARRIER (@var{label})
-The alignment (log base 2) to put in front of @var{label}, which follows
-a @code{BARRIER}.
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-@end defmac
-
-@defmac LOOP_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label} that heads
-a frequently executed basic block (usually the header of a loop).
-
-This macro need not be defined if you don't want any special alignment
-to be done at such a time. Most machine descriptions do not currently
-define the macro.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @code{align_loops} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @code{align_loops} in a @code{LOOP_ALIGN} implementation.
-@end defmac
-
-@defmac LABEL_ALIGN (@var{label})
-The alignment (log base 2) to put in front of @var{label}.
-If @code{LABEL_ALIGN_AFTER_BARRIER} / @code{LOOP_ALIGN} specify a different alignment,
-the maximum of the specified values is used.
-
-Unless it's necessary to inspect the @var{label} parameter, it is better
-to set the variable @code{align_labels} in the target's
-@code{TARGET_OPTION_OVERRIDE}. Otherwise, you should try to honor the user's
-selection in @code{align_labels} in a @code{LABEL_ALIGN} implementation.
-@end defmac
-
-@defmac ASM_OUTPUT_SKIP (@var{stream}, @var{nbytes})
-A C statement to output to the stdio stream @var{stream} an assembler
-instruction to advance the location counter by @var{nbytes} bytes.
-Those bytes should be zero when loaded. @var{nbytes} will be a C
-expression of type @code{unsigned HOST_WIDE_INT}.
-@end defmac
-
-@defmac ASM_NO_SKIP_IN_TEXT
-Define this macro if @code{ASM_OUTPUT_SKIP} should not be used in the
-text section because it fails to put zeros in the bytes that are skipped.
-This is true on many Unix systems, where the pseudo--op to skip bytes
-produces no-op instructions rather than zeros when used in the text
-section.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGN (@var{stream}, @var{power})
-A C statement to output to the stdio stream @var{stream} an assembler
-command to advance the location counter to a multiple of 2 to the
-@var{power} bytes. @var{power} will be a C expression of type @code{int}.
-@end defmac
-
-@defmac ASM_OUTPUT_ALIGN_WITH_NOP (@var{stream}, @var{power})
-Like @code{ASM_OUTPUT_ALIGN}, except that the ``nop'' instruction is used
-for padding, if necessary.
-@end defmac
-
-@defmac ASM_OUTPUT_MAX_SKIP_ALIGN (@var{stream}, @var{power}, @var{max_skip})
-A C statement to output to the stdio stream @var{stream} an assembler
-command to advance the location counter to a multiple of 2 to the
-@var{power} bytes, but only if @var{max_skip} or fewer bytes are needed to
-satisfy the alignment request. @var{power} and @var{max_skip} will be
-a C expression of type @code{int}.
-@end defmac
-
-@need 3000
-@node Debugging Info
-@section Controlling Debugging Information Format
-
-@c prevent bad page break with this line
-This describes how to specify debugging information.
-
-@menu
-* All Debuggers:: Macros that affect all debugging formats uniformly.
-* DBX Options:: Macros enabling specific options in DBX format.
-* DBX Hooks:: Hook macros for varying DBX format.
-* File Names and DBX:: Macros controlling output of file names in DBX format.
-* DWARF:: Macros for DWARF format.
-* VMS Debug:: Macros for VMS debug format.
-* CTF Debug:: Macros for CTF debug format.
-* BTF Debug:: Macros for BTF debug format.
-@end menu
-
-@node All Debuggers
-@subsection Macros Affecting All Debugging Formats
-
-@c prevent bad page break with this line
-These macros affect all debugging formats.
-
-@defmac DBX_REGISTER_NUMBER (@var{regno})
-A C expression that returns the DBX register number for the compiler
-register number @var{regno}. In the default macro provided, the value
-of this expression will be @var{regno} itself. But sometimes there are
-some registers that the compiler knows about and DBX does not, or vice
-versa. In such cases, some register may need to have one number in the
-compiler and another for DBX@.
-
-If two registers have consecutive numbers inside GCC, and they can be
-used as a pair to hold a multiword value, then they @emph{must} have
-consecutive numbers after renumbering with @code{DBX_REGISTER_NUMBER}.
-Otherwise, debuggers will be unable to access such a pair, because they
-expect register pairs to be consecutive in their own numbering scheme.
-
-If you find yourself defining @code{DBX_REGISTER_NUMBER} in way that
-does not preserve register pairs, then what you must do instead is
-redefine the actual register numbering scheme.
-@end defmac
-
-@defmac DEBUGGER_AUTO_OFFSET (@var{x})
-A C expression that returns the integer offset value for an automatic
-variable having address @var{x} (an RTL expression). The default
-computation assumes that @var{x} is based on the frame-pointer and
-gives the offset from the frame-pointer. This is required for targets
-that produce debugging output for DBX and allow the frame-pointer to be
-eliminated when the @option{-g} option is used.
-@end defmac
-
-@defmac DEBUGGER_ARG_OFFSET (@var{offset}, @var{x})
-A C expression that returns the integer offset value for an argument
-having address @var{x} (an RTL expression). The nominal offset is
-@var{offset}.
-@end defmac
-
-@defmac PREFERRED_DEBUGGING_TYPE
-A C expression that returns the type of debugging output GCC should
-produce when the user specifies just @option{-g}. Define
-this if you have arranged for GCC to support more than one format of
-debugging output. Currently, the allowable values are @code{DBX_DEBUG},
-@code{DWARF2_DEBUG}, @code{XCOFF_DEBUG}, @code{VMS_DEBUG},
-and @code{VMS_AND_DWARF2_DEBUG}.
-
-When the user specifies @option{-ggdb}, GCC normally also uses the
-value of this macro to select the debugging output format, but with two
-exceptions. If @code{DWARF2_DEBUGGING_INFO} is defined, GCC uses the
-value @code{DWARF2_DEBUG}. Otherwise, if @code{DBX_DEBUGGING_INFO} is
-defined, GCC uses @code{DBX_DEBUG}.
-
-The value of this macro only affects the default debugging output; the
-user can always get a specific type of output by using @option{-gstabs},
-@option{-gdwarf-2}, @option{-gxcoff}, or @option{-gvms}.
-@end defmac
-
-@node DBX Options
-@subsection Specific Options for DBX Output
-
-@c prevent bad page break with this line
-These are specific options for DBX output.
-
-@defmac DBX_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output for DBX
-in response to the @option{-g} option.
-@end defmac
-
-@defmac XCOFF_DEBUGGING_INFO
-Define this macro if GCC should produce XCOFF format debugging output
-in response to the @option{-g} option. This is a variant of DBX format.
-@end defmac
-
-@defmac DEFAULT_GDB_EXTENSIONS
-Define this macro to control whether GCC should by default generate
-GDB's extended version of DBX debugging information (assuming DBX-format
-debugging information is enabled at all). If you don't define the
-macro, the default is 1: always generate the extended information
-if there is any occasion to.
-@end defmac
-
-@defmac DEBUG_SYMS_TEXT
-Define this macro if all @code{.stabs} commands should be output while
-in the text section.
-@end defmac
-
-@defmac ASM_STABS_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabs\t"} to define an ordinary debugging symbol.
-If you don't define this macro, @code{"\t.stabs\t"} is used. This macro
-applies only to DBX debugging information format.
-@end defmac
-
-@defmac ASM_STABD_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabd\t"} to define a debugging symbol whose
-value is the current location. If you don't define this macro,
-@code{"\t.stabd\t"} is used. This macro applies only to DBX debugging
-information format.
-@end defmac
-
-@defmac ASM_STABN_OP
-A C string constant, including spacing, naming the assembler pseudo op to
-use instead of @code{"\t.stabn\t"} to define a debugging symbol with no
-name. If you don't define this macro, @code{"\t.stabn\t"} is used. This
-macro applies only to DBX debugging information format.
-@end defmac
-
-@defmac DBX_NO_XREFS
-Define this macro if DBX on your system does not support the construct
-@samp{xs@var{tagname}}. On some systems, this construct is used to
-describe a forward reference to a structure named @var{tagname}.
-On other systems, this construct is not supported at all.
-@end defmac
-
-@defmac DBX_CONTIN_LENGTH
-A symbol name in DBX-format debugging information is normally
-continued (split into two separate @code{.stabs} directives) when it
-exceeds a certain length (by default, 80 characters). On some
-operating systems, DBX requires this splitting; on others, splitting
-must not be done. You can inhibit splitting by defining this macro
-with the value zero. You can override the default splitting-length by
-defining this macro as an expression for the length you desire.
-@end defmac
-
-@defmac DBX_CONTIN_CHAR
-Normally continuation is indicated by adding a @samp{\} character to
-the end of a @code{.stabs} string when a continuation follows. To use
-a different character instead, define this macro as a character
-constant for the character you want to use. Do not define this macro
-if backslash is correct for your system.
-@end defmac
-
-@defmac DBX_STATIC_STAB_DATA_SECTION
-Define this macro if it is necessary to go to the data section before
-outputting the @samp{.stabs} pseudo-op for a non-global static
-variable.
-@end defmac
-
-@defmac DBX_TYPE_DECL_STABS_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a typedef. The default is @code{N_LSYM}.
-@end defmac
-
-@defmac DBX_STATIC_CONST_VAR_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a static variable located in the text section. DBX format does not
-provide any ``right'' way to do this. The default is @code{N_FUN}.
-@end defmac
-
-@defmac DBX_REGPARM_STABS_CODE
-The value to use in the ``code'' field of the @code{.stabs} directive
-for a parameter passed in registers. DBX format does not provide any
-``right'' way to do this. The default is @code{N_RSYM}.
-@end defmac
-
-@defmac DBX_REGPARM_STABS_LETTER
-The letter to use in DBX symbol data to identify a symbol as a parameter
-passed in registers. DBX format does not customarily provide any way to
-do this. The default is @code{'P'}.
-@end defmac
-
-@defmac DBX_FUNCTION_FIRST
-Define this macro if the DBX information for a function and its
-arguments should precede the assembler code for the function. Normally,
-in DBX format, the debugging information entirely follows the assembler
-code.
-@end defmac
-
-@defmac DBX_BLOCKS_FUNCTION_RELATIVE
-Define this macro, with value 1, if the value of a symbol describing
-the scope of a block (@code{N_LBRAC} or @code{N_RBRAC}) should be
-relative to the start of the enclosing function. Normally, GCC uses
-an absolute address.
-@end defmac
-
-@defmac DBX_LINES_FUNCTION_RELATIVE
-Define this macro, with value 1, if the value of a symbol indicating
-the current line number (@code{N_SLINE}) should be relative to the
-start of the enclosing function. Normally, GCC uses an absolute address.
-@end defmac
-
-@defmac DBX_USE_BINCL
-Define this macro if GCC should generate @code{N_BINCL} and
-@code{N_EINCL} stabs for included header files, as on Sun systems. This
-macro also directs GCC to output a type number as a pair of a file
-number and a type number within the file. Normally, GCC does not
-generate @code{N_BINCL} or @code{N_EINCL} stabs, and it outputs a single
-number for a type number.
-@end defmac
-
-@node DBX Hooks
-@subsection Open-Ended Hooks for DBX Format
-
-@c prevent bad page break with this line
-These are hooks for DBX format.
-
-@defmac DBX_OUTPUT_SOURCE_LINE (@var{stream}, @var{line}, @var{counter})
-A C statement to output DBX debugging information before code for line
-number @var{line} of the current source file to the stdio stream
-@var{stream}. @var{counter} is the number of time the macro was
-invoked, including the current invocation; it is intended to generate
-unique labels in the assembly output.
-
-This macro should not be defined if the default output is correct, or
-if it can be made correct by defining @code{DBX_LINES_FUNCTION_RELATIVE}.
-@end defmac
-
-@defmac NO_DBX_FUNCTION_END
-Some stabs encapsulation formats (in particular ECOFF), cannot handle the
-@code{.stabs "",N_FUN,,0,0,Lscope-function-1} gdb dbx extension construct.
-On those machines, define this macro to turn this feature off without
-disturbing the rest of the gdb extensions.
-@end defmac
-
-@defmac NO_DBX_BNSYM_ENSYM
-Some assemblers cannot handle the @code{.stabd BNSYM/ENSYM,0,0} gdb dbx
-extension construct. On those machines, define this macro to turn this
-feature off without disturbing the rest of the gdb extensions.
-@end defmac
-
-@node File Names and DBX
-@subsection File Names in DBX Format
-
-@c prevent bad page break with this line
-This describes file names in DBX format.
-
-@defmac DBX_OUTPUT_MAIN_SOURCE_FILENAME (@var{stream}, @var{name})
-A C statement to output DBX debugging information to the stdio stream
-@var{stream}, which indicates that file @var{name} is the main source
-file---the file specified as the input file for compilation.
-This macro is called only once, at the beginning of compilation.
-
-This macro need not be defined if the standard form of output
-for DBX debugging information is appropriate.
-
-It may be necessary to refer to a label equal to the beginning of the
-text section. You can use @samp{assemble_name (stream, ltext_label_name)}
-to do so. If you do this, you must also set the variable
-@var{used_ltext_label_name} to @code{true}.
-@end defmac
-
-@defmac NO_DBX_MAIN_SOURCE_DIRECTORY
-Define this macro, with value 1, if GCC should not emit an indication
-of the current directory for compilation and current source language at
-the beginning of the file.
-@end defmac
-
-@defmac NO_DBX_GCC_MARKER
-Define this macro, with value 1, if GCC should not emit an indication
-that this object file was compiled by GCC@. The default is to emit
-an @code{N_OPT} stab at the beginning of every source file, with
-@samp{gcc2_compiled.} for the string and value 0.
-@end defmac
-
-@defmac DBX_OUTPUT_MAIN_SOURCE_FILE_END (@var{stream}, @var{name})
-A C statement to output DBX debugging information at the end of
-compilation of the main source file @var{name}. Output should be
-written to the stdio stream @var{stream}.
-
-If you don't define this macro, nothing special is output at the end
-of compilation, which is correct for most machines.
-@end defmac
-
-@defmac DBX_OUTPUT_NULL_N_SO_AT_MAIN_SOURCE_FILE_END
-Define this macro @emph{instead of} defining
-@code{DBX_OUTPUT_MAIN_SOURCE_FILE_END}, if what needs to be output at
-the end of compilation is an @code{N_SO} stab with an empty string,
-whose value is the highest absolute text address in the file.
-@end defmac
-
-@need 2000
-@node DWARF
-@subsection Macros for DWARF Output
-
-@c prevent bad page break with this line
-Here are macros for DWARF output.
-
-@defmac DWARF2_DEBUGGING_INFO
-Define this macro if GCC should produce dwarf version 2 format
-debugging output in response to the @option{-g} option.
-
-@hook TARGET_DWARF_CALLING_CONVENTION
-
-To support optional call frame debugging information, you must also
-define @code{INCOMING_RETURN_ADDR_RTX} and either set
-@code{RTX_FRAME_RELATED_P} on the prologue insns if you use RTL for the
-prologue, or call @code{dwarf2out_def_cfa} and @code{dwarf2out_reg_save}
-as appropriate from @code{TARGET_ASM_FUNCTION_PROLOGUE} if you don't.
-@end defmac
-
-@defmac DWARF2_FRAME_INFO
-Define this macro to a nonzero value if GCC should always output
-Dwarf 2 frame information. If @code{TARGET_EXCEPT_UNWIND_INFO}
-(@pxref{Exception Region Output}) returns @code{UI_DWARF2}, and
-exceptions are enabled, GCC will output this information not matter
-how you define @code{DWARF2_FRAME_INFO}.
-@end defmac
-
-@hook TARGET_DEBUG_UNWIND_INFO
-
-@defmac DWARF2_ASM_LINE_DEBUG_INFO
-Define this macro to be a nonzero value if the assembler can generate Dwarf 2
-line debug info sections. This will result in much more compact line number
-tables, and hence is desirable if it works.
-@end defmac
-
-@defmac DWARF2_ASM_VIEW_DEBUG_INFO
-Define this macro to be a nonzero value if the assembler supports view
-assignment and verification in @code{.loc}. If it does not, but the
-user enables location views, the compiler may have to fallback to
-internal line number tables.
-@end defmac
-
-@hook TARGET_RESET_LOCATION_VIEW
-
-@hook TARGET_WANT_DEBUG_PUB_SECTIONS
-
-@hook TARGET_DELAY_SCHED2
-
-@hook TARGET_DELAY_VARTRACK
-
-@hook TARGET_NO_REGISTER_ALLOCATION
-
-@defmac ASM_OUTPUT_DWARF_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
-A C statement to issue assembly directives that create a difference
-@var{lab1} minus @var{lab2}, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_VMS_DELTA (@var{stream}, @var{size}, @var{label1}, @var{label2})
-A C statement to issue assembly directives that create a difference
-between the two given labels in system defined units, e.g.@: instruction
-slots on IA64 VMS, using an integer of the given size.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_OFFSET (@var{stream}, @var{size}, @var{label}, @var{offset}, @var{section})
-A C statement to issue assembly directives that create a
-section-relative reference to the given @var{label} plus @var{offset}, using
-an integer of the given @var{size}. The label is known to be defined in the
-given @var{section}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_PCREL (@var{stream}, @var{size}, @var{label})
-A C statement to issue assembly directives that create a self-relative
-reference to the given @var{label}, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_DATAREL (@var{stream}, @var{size}, @var{label})
-A C statement to issue assembly directives that create a reference to the
-given @var{label} relative to the dbase, using an integer of the given @var{size}.
-@end defmac
-
-@defmac ASM_OUTPUT_DWARF_TABLE_REF (@var{label})
-A C statement to issue assembly directives that create a reference to
-the DWARF table identifier @var{label} from the current section. This
-is used on some systems to avoid garbage collecting a DWARF table which
-is referenced by a function.
-@end defmac
-
-@hook TARGET_ASM_OUTPUT_DWARF_DTPREL
-
-@need 2000
-@node VMS Debug
-@subsection Macros for VMS Debug Format
-
-@c prevent bad page break with this line
-Here are macros for VMS debug format.
-
-@defmac VMS_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output for VMS
-in response to the @option{-g} option. The default behavior for VMS
-is to generate minimal debug info for a traceback in the absence of
-@option{-g} unless explicitly overridden with @option{-g0}. This
-behavior is controlled by @code{TARGET_OPTION_OPTIMIZATION} and
-@code{TARGET_OPTION_OVERRIDE}.
-@end defmac
-
-@need 2000
-@node CTF Debug
-@subsection Macros for CTF Debug Format
-
-@c prevent bad page break with this line
-Here are macros for CTF debug format.
-
-@defmac CTF_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output in CTF debug
-format in response to the @option{-gctf} option.
-@end defmac
-
-@need 2000
-@node BTF Debug
-@subsection Macros for BTF Debug Format
-
-@c prevent bad page break with this line
-Here are macros for BTF debug format.
-
-@defmac BTF_DEBUGGING_INFO
-Define this macro if GCC should produce debugging output in BTF debug
-format in response to the @option{-gbtf} option.
-@end defmac
-
-@node Floating Point
-@section Cross Compilation and Floating Point
-@cindex cross compilation and floating point
-@cindex floating point and cross compilation
-
-While all modern machines use twos-complement representation for integers,
-there are a variety of representations for floating point numbers. This
-means that in a cross-compiler the representation of floating point numbers
-in the compiled program may be different from that used in the machine
-doing the compilation.
-
-Because different representation systems may offer different amounts of
-range and precision, all floating point constants must be represented in
-the target machine's format. Therefore, the cross compiler cannot
-safely use the host machine's floating point arithmetic; it must emulate
-the target's arithmetic. To ensure consistency, GCC always uses
-emulation to work with floating point values, even when the host and
-target floating point formats are identical.
-
-The following macros are provided by @file{real.h} for the compiler to
-use. All parts of the compiler which generate or optimize
-floating-point calculations must use these macros. They may evaluate
-their operands more than once, so operands must not have side effects.
-
-@defmac REAL_VALUE_TYPE
-The C data type to be used to hold a floating point value in the target
-machine's format. Typically this is a @code{struct} containing an
-array of @code{HOST_WIDE_INT}, but all code should treat it as an opaque
-quantity.
-@end defmac
-
-@deftypefn Macro HOST_WIDE_INT REAL_VALUE_FIX (REAL_VALUE_TYPE @var{x})
-Truncates @var{x} to a signed integer, rounding toward zero.
-@end deftypefn
-
-@deftypefn Macro {unsigned HOST_WIDE_INT} REAL_VALUE_UNSIGNED_FIX (REAL_VALUE_TYPE @var{x})
-Truncates @var{x} to an unsigned integer, rounding toward zero. If
-@var{x} is negative, returns zero.
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ATOF (const char *@var{string}, machine_mode @var{mode})
-Converts @var{string} into a floating point number in the target machine's
-representation for mode @var{mode}. This routine can handle both
-decimal and hexadecimal floating point constants, using the syntax
-defined by the C language for both.
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_NEGATIVE (REAL_VALUE_TYPE @var{x})
-Returns 1 if @var{x} is negative (including negative zero), 0 otherwise.
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_ISINF (REAL_VALUE_TYPE @var{x})
-Determines whether @var{x} represents infinity (positive or negative).
-@end deftypefn
-
-@deftypefn Macro int REAL_VALUE_ISNAN (REAL_VALUE_TYPE @var{x})
-Determines whether @var{x} represents a ``NaN'' (not-a-number).
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_NEGATE (REAL_VALUE_TYPE @var{x})
-Returns the negative of the floating point value @var{x}.
-@end deftypefn
-
-@deftypefn Macro REAL_VALUE_TYPE REAL_VALUE_ABS (REAL_VALUE_TYPE @var{x})
-Returns the absolute value of @var{x}.
-@end deftypefn
-
-@node Mode Switching
-@section Mode Switching Instructions
-@cindex mode switching
-The following macros control mode switching optimizations:
-
-@defmac OPTIMIZE_MODE_SWITCHING (@var{entity})
-Define this macro if the port needs extra instructions inserted for mode
-switching in an optimizing compilation.
-
-For an example, the SH4 can perform both single and double precision
-floating point operations, but to perform a single precision operation,
-the FPSCR PR bit has to be cleared, while for a double precision
-operation, this bit has to be set. Changing the PR bit requires a general
-purpose register as a scratch register, hence these FPSCR sets have to
-be inserted before reload, i.e.@: you cannot put this into instruction emitting
-or @code{TARGET_MACHINE_DEPENDENT_REORG}.
-
-You can have multiple entities that are mode-switched, and select at run time
-which entities actually need it. @code{OPTIMIZE_MODE_SWITCHING} should
-return nonzero for any @var{entity} that needs mode-switching.
-If you define this macro, you also have to define
-@code{NUM_MODES_FOR_MODE_SWITCHING}, @code{TARGET_MODE_NEEDED},
-@code{TARGET_MODE_PRIORITY} and @code{TARGET_MODE_EMIT}.
-@code{TARGET_MODE_AFTER}, @code{TARGET_MODE_ENTRY}, and @code{TARGET_MODE_EXIT}
-are optional.
-@end defmac
-
-@defmac NUM_MODES_FOR_MODE_SWITCHING
-If you define @code{OPTIMIZE_MODE_SWITCHING}, you have to define this as
-initializer for an array of integers. Each initializer element
-N refers to an entity that needs mode switching, and specifies the number
-of different modes that might need to be set for this entity.
-The position of the initializer in the initializer---starting counting at
-zero---determines the integer that is used to refer to the mode-switched
-entity in question.
-In macros that take mode arguments / yield a mode result, modes are
-represented as numbers 0 @dots{} N @minus{} 1. N is used to specify that no mode
-switch is needed / supplied.
-@end defmac
-
-@hook TARGET_MODE_EMIT
-
-@hook TARGET_MODE_NEEDED
-
-@hook TARGET_MODE_AFTER
-
-@hook TARGET_MODE_ENTRY
-
-@hook TARGET_MODE_EXIT
-
-@hook TARGET_MODE_PRIORITY
-
-@node Target Attributes
-@section Defining target-specific uses of @code{__attribute__}
-@cindex target attributes
-@cindex machine attributes
-@cindex attributes, target-specific
-
-Target-specific attributes may be defined for functions, data and types.
-These are described using the following target hooks; they also need to
-be documented in @file{extend.texi}.
-
-@hook TARGET_ATTRIBUTE_TABLE
-
-@hook TARGET_ATTRIBUTE_TAKES_IDENTIFIER_P
-
-@hook TARGET_COMP_TYPE_ATTRIBUTES
-
-@hook TARGET_SET_DEFAULT_TYPE_ATTRIBUTES
-
-@hook TARGET_MERGE_TYPE_ATTRIBUTES
-
-@hook TARGET_MERGE_DECL_ATTRIBUTES
-
-@hook TARGET_VALID_DLLIMPORT_ATTRIBUTE_P
-
-@defmac TARGET_DECLSPEC
-Define this macro to a nonzero value if you want to treat
-@code{__declspec(X)} as equivalent to @code{__attribute((X))}. By
-default, this behavior is enabled only for targets that define
-@code{TARGET_DLLIMPORT_DECL_ATTRIBUTES}. The current implementation
-of @code{__declspec} is via a built-in macro, but you should not rely
-on this implementation detail.
-@end defmac
-
-@hook TARGET_INSERT_ATTRIBUTES
-
-@hook TARGET_HANDLE_GENERIC_ATTRIBUTE
-
-@hook TARGET_FUNCTION_ATTRIBUTE_INLINABLE_P
-
-@hook TARGET_OPTION_VALID_ATTRIBUTE_P
-
-@hook TARGET_OPTION_SAVE
-
-@hook TARGET_OPTION_RESTORE
-
-@hook TARGET_OPTION_POST_STREAM_IN
-
-@hook TARGET_OPTION_PRINT
-
-@hook TARGET_OPTION_PRAGMA_PARSE
-
-@hook TARGET_OPTION_OVERRIDE
-
-@hook TARGET_OPTION_FUNCTION_VERSIONS
-
-@hook TARGET_CAN_INLINE_P
-
-@hook TARGET_UPDATE_IPA_FN_TARGET_INFO
-
-@hook TARGET_NEED_IPA_FN_TARGET_INFO
-
-@hook TARGET_RELAYOUT_FUNCTION
-
-@node Emulated TLS
-@section Emulating TLS
-@cindex Emulated TLS
-
-For targets whose psABI does not provide Thread Local Storage via
-specific relocations and instruction sequences, an emulation layer is
-used. A set of target hooks allows this emulation layer to be
-configured for the requirements of a particular target. For instance
-the psABI may in fact specify TLS support in terms of an emulation
-layer.
-
-The emulation layer works by creating a control object for every TLS
-object. To access the TLS object, a lookup function is provided
-which, when given the address of the control object, will return the
-address of the current thread's instance of the TLS object.
-
-@hook TARGET_EMUTLS_GET_ADDRESS
-
-@hook TARGET_EMUTLS_REGISTER_COMMON
-
-@hook TARGET_EMUTLS_VAR_SECTION
-
-@hook TARGET_EMUTLS_TMPL_SECTION
-
-@hook TARGET_EMUTLS_VAR_PREFIX
-
-@hook TARGET_EMUTLS_TMPL_PREFIX
-
-@hook TARGET_EMUTLS_VAR_FIELDS
-
-@hook TARGET_EMUTLS_VAR_INIT
-
-@hook TARGET_EMUTLS_VAR_ALIGN_FIXED
-
-@hook TARGET_EMUTLS_DEBUG_FORM_TLS_ADDRESS
-
-@node MIPS Coprocessors
-@section Defining coprocessor specifics for MIPS targets.
-@cindex MIPS coprocessor-definition macros
-
-The MIPS specification allows MIPS implementations to have as many as 4
-coprocessors, each with as many as 32 private registers. GCC supports
-accessing these registers and transferring values between the registers
-and memory using asm-ized variables. For example:
-
-@smallexample
- register unsigned int cp0count asm ("c0r1");
- unsigned int d;
-
- d = cp0count + 3;
-@end smallexample
-
-(``c0r1'' is the default name of register 1 in coprocessor 0; alternate
-names may be added as described below, or the default names may be
-overridden entirely in @code{SUBTARGET_CONDITIONAL_REGISTER_USAGE}.)
-
-Coprocessor registers are assumed to be epilogue-used; sets to them will
-be preserved even if it does not appear that the register is used again
-later in the function.
-
-Another note: according to the MIPS spec, coprocessor 1 (if present) is
-the FPU@. One accesses COP1 registers through standard mips
-floating-point support; they are not included in this mechanism.
-
-@node PCH Target
-@section Parameters for Precompiled Header Validity Checking
-@cindex parameters, precompiled headers
-
-@hook TARGET_GET_PCH_VALIDITY
-
-@hook TARGET_PCH_VALID_P
-
-@hook TARGET_CHECK_PCH_TARGET_FLAGS
-
-@hook TARGET_PREPARE_PCH_SAVE
-
-@node C++ ABI
-@section C++ ABI parameters
-@cindex parameters, c++ abi
-
-@hook TARGET_CXX_GUARD_TYPE
-
-@hook TARGET_CXX_GUARD_MASK_BIT
-
-@hook TARGET_CXX_GET_COOKIE_SIZE
-
-@hook TARGET_CXX_COOKIE_HAS_SIZE
-
-@hook TARGET_CXX_IMPORT_EXPORT_CLASS
-
-@hook TARGET_CXX_CDTOR_RETURNS_THIS
-
-@hook TARGET_CXX_KEY_METHOD_MAY_BE_INLINE
-
-@hook TARGET_CXX_DETERMINE_CLASS_DATA_VISIBILITY
-
-@hook TARGET_CXX_CLASS_DATA_ALWAYS_COMDAT
-
-@hook TARGET_CXX_LIBRARY_RTTI_COMDAT
-
-@hook TARGET_CXX_USE_AEABI_ATEXIT
-
-@hook TARGET_CXX_USE_ATEXIT_FOR_CXA_ATEXIT
-
-@hook TARGET_CXX_ADJUST_CLASS_AT_DEFINITION
-
-@hook TARGET_CXX_DECL_MANGLING_CONTEXT
-
-@node D Language and ABI
-@section D ABI parameters
-@cindex parameters, d abi
-
-@hook TARGET_D_CPU_VERSIONS
-
-@hook TARGET_D_OS_VERSIONS
-
-@hook TARGET_D_REGISTER_CPU_TARGET_INFO
-
-@hook TARGET_D_REGISTER_OS_TARGET_INFO
-
-@hook TARGET_D_MINFO_SECTION
-
-@hook TARGET_D_MINFO_START_NAME
-
-@hook TARGET_D_MINFO_END_NAME
-
-@hook TARGET_D_HAS_STDCALL_CONVENTION
-
-@hook TARGET_D_TEMPLATES_ALWAYS_COMDAT
-
-@node Named Address Spaces
-@section Adding support for named address spaces
-@cindex named address spaces
-
-The draft technical report of the ISO/IEC JTC1 S22 WG14 N1275
-standards committee, @cite{Programming Languages - C - Extensions to
-support embedded processors}, specifies a syntax for embedded
-processors to specify alternate address spaces. You can configure a
-GCC port to support section 5.1 of the draft report to add support for
-address spaces other than the default address space. These address
-spaces are new keywords that are similar to the @code{volatile} and
-@code{const} type attributes.
-
-Pointers to named address spaces can have a different size than
-pointers to the generic address space.
-
-For example, the SPU port uses the @code{__ea} address space to refer
-to memory in the host processor, rather than memory local to the SPU
-processor. Access to memory in the @code{__ea} address space involves
-issuing DMA operations to move data between the host processor and the
-local processor memory address space. Pointers in the @code{__ea}
-address space are either 32 bits or 64 bits based on the
-@option{-mea32} or @option{-mea64} switches (native SPU pointers are
-always 32 bits).
-
-Internally, address spaces are represented as a small integer in the
-range 0 to 15 with address space 0 being reserved for the generic
-address space.
-
-To register a named address space qualifier keyword with the C front end,
-the target may call the @code{c_register_addr_space} routine. For example,
-the SPU port uses the following to declare @code{__ea} as the keyword for
-named address space #1:
-@smallexample
-#define ADDR_SPACE_EA 1
-c_register_addr_space ("__ea", ADDR_SPACE_EA);
-@end smallexample
-
-@hook TARGET_ADDR_SPACE_POINTER_MODE
-
-@hook TARGET_ADDR_SPACE_ADDRESS_MODE
-
-@hook TARGET_ADDR_SPACE_VALID_POINTER_MODE
-
-@hook TARGET_ADDR_SPACE_LEGITIMATE_ADDRESS_P
-
-@hook TARGET_ADDR_SPACE_LEGITIMIZE_ADDRESS
-
-@hook TARGET_ADDR_SPACE_SUBSET_P
-
-@hook TARGET_ADDR_SPACE_ZERO_ADDRESS_VALID
-
-@hook TARGET_ADDR_SPACE_CONVERT
-
-@hook TARGET_ADDR_SPACE_DEBUG
-
-@hook TARGET_ADDR_SPACE_DIAGNOSE_USAGE
-
-@node Misc
-@section Miscellaneous Parameters
-@cindex parameters, miscellaneous
-
-@c prevent bad page break with this line
-Here are several miscellaneous parameters.
-
-@defmac HAS_LONG_COND_BRANCH
-Define this boolean macro to indicate whether or not your architecture
-has conditional branches that can span all of memory. It is used in
-conjunction with an optimization that partitions hot and cold basic
-blocks into separate sections of the executable. If this macro is
-set to false, gcc will convert any conditional branches that attempt
-to cross between sections into unconditional branches or indirect jumps.
-@end defmac
-
-@defmac HAS_LONG_UNCOND_BRANCH
-Define this boolean macro to indicate whether or not your architecture
-has unconditional branches that can span all of memory. It is used in
-conjunction with an optimization that partitions hot and cold basic
-blocks into separate sections of the executable. If this macro is
-set to false, gcc will convert any unconditional branches that attempt
-to cross between sections into indirect jumps.
-@end defmac
-
-@defmac CASE_VECTOR_MODE
-An alias for a machine mode name. This is the machine mode that
-elements of a jump-table should have.
-@end defmac
-
-@defmac CASE_VECTOR_SHORTEN_MODE (@var{min_offset}, @var{max_offset}, @var{body})
-Optional: return the preferred mode for an @code{addr_diff_vec}
-when the minimum and maximum offset are known. If you define this,
-it enables extra code in branch shortening to deal with @code{addr_diff_vec}.
-To make this work, you also have to define @code{INSN_ALIGN} and
-make the alignment for @code{addr_diff_vec} explicit.
-The @var{body} argument is provided so that the offset_unsigned and scale
-flags can be updated.
-@end defmac
-
-@defmac CASE_VECTOR_PC_RELATIVE
-Define this macro to be a C expression to indicate when jump-tables
-should contain relative addresses. You need not define this macro if
-jump-tables never contain relative addresses, or jump-tables should
-contain relative addresses only when @option{-fPIC} or @option{-fPIC}
-is in effect.
-@end defmac
-
-@hook TARGET_CASE_VALUES_THRESHOLD
-
-@defmac WORD_REGISTER_OPERATIONS
-Define this macro to 1 if operations between registers with integral mode
-smaller than a word are always performed on the entire register. To be
-more explicit, if you start with a pair of @code{word_mode} registers with
-known values and you do a subword, for example @code{QImode}, addition on
-the low part of the registers, then the compiler may consider that the
-result has a known value in @code{word_mode} too if the macro is defined
-to 1. Most RISC machines have this property and most CISC machines do not.
-@end defmac
-
-@hook TARGET_MIN_ARITHMETIC_PRECISION
-
-@defmac LOAD_EXTEND_OP (@var{mem_mode})
-Define this macro to be a C expression indicating when insns that read
-memory in @var{mem_mode}, an integral mode narrower than a word, set the
-bits outside of @var{mem_mode} to be either the sign-extension or the
-zero-extension of the data read. Return @code{SIGN_EXTEND} for values
-of @var{mem_mode} for which the
-insn sign-extends, @code{ZERO_EXTEND} for which it zero-extends, and
-@code{UNKNOWN} for other modes.
-
-This macro is not called with @var{mem_mode} non-integral or with a width
-greater than or equal to @code{BITS_PER_WORD}, so you may return any
-value in this case. Do not define this macro if it would always return
-@code{UNKNOWN}. On machines where this macro is defined, you will normally
-define it as the constant @code{SIGN_EXTEND} or @code{ZERO_EXTEND}.
-
-You may return a non-@code{UNKNOWN} value even if for some hard registers
-the sign extension is not performed, if for the @code{REGNO_REG_CLASS}
-of these hard registers @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false
-when the @var{from} mode is @var{mem_mode} and the @var{to} mode is any
-integral mode larger than this but not larger than @code{word_mode}.
-
-You must return @code{UNKNOWN} if for some hard registers that allow this
-mode, @code{TARGET_CAN_CHANGE_MODE_CLASS} says that they cannot change to
-@code{word_mode}, but that they can change to another integral mode that
-is larger then @var{mem_mode} but still smaller than @code{word_mode}.
-@end defmac
-
-@defmac SHORT_IMMEDIATES_SIGN_EXTEND
-Define this macro to 1 if loading short immediate values into registers sign
-extends.
-@end defmac
-
-@hook TARGET_MIN_DIVISIONS_FOR_RECIP_MUL
-
-@defmac MOVE_MAX
-The maximum number of bytes that a single instruction can move quickly
-between memory and registers or between two memory locations.
-@end defmac
-
-@defmac MAX_MOVE_MAX
-The maximum number of bytes that a single instruction can move quickly
-between memory and registers or between two memory locations. If this
-is undefined, the default is @code{MOVE_MAX}. Otherwise, it is the
-constant value that is the largest value that @code{MOVE_MAX} can have
-at run-time.
-@end defmac
-
-@defmac SHIFT_COUNT_TRUNCATED
-A C expression that is nonzero if on this machine the number of bits
-actually used for the count of a shift operation is equal to the number
-of bits needed to represent the size of the object being shifted. When
-this macro is nonzero, the compiler will assume that it is safe to omit
-a sign-extend, zero-extend, and certain bitwise `and' instructions that
-truncates the count of a shift operation. On machines that have
-instructions that act on bit-fields at variable positions, which may
-include `bit test' instructions, a nonzero @code{SHIFT_COUNT_TRUNCATED}
-also enables deletion of truncations of the values that serve as
-arguments to bit-field instructions.
-
-If both types of instructions truncate the count (for shifts) and
-position (for bit-field operations), or if no variable-position bit-field
-instructions exist, you should define this macro.
-
-However, on some machines, such as the 80386 and the 680x0, truncation
-only applies to shift operations and not the (real or pretended)
-bit-field operations. Define @code{SHIFT_COUNT_TRUNCATED} to be zero on
-such machines. Instead, add patterns to the @file{md} file that include
-the implied truncation of the shift instructions.
-
-You need not define this macro if it would always have the value of zero.
-@end defmac
-
-@anchor{TARGET_SHIFT_TRUNCATION_MASK}
-@hook TARGET_SHIFT_TRUNCATION_MASK
-
-@hook TARGET_TRULY_NOOP_TRUNCATION
-
-@hook TARGET_MODE_REP_EXTENDED
-
-@hook TARGET_SETJMP_PRESERVES_NONVOLATILE_REGS_P
-
-@defmac STORE_FLAG_VALUE
-A C expression describing the value returned by a comparison operator
-with an integral mode and stored by a store-flag instruction
-(@samp{cstore@var{mode}4}) when the condition is true. This description must
-apply to @emph{all} the @samp{cstore@var{mode}4} patterns and all the
-comparison operators whose results have a @code{MODE_INT} mode.
-
-A value of 1 or @minus{}1 means that the instruction implementing the
-comparison operator returns exactly 1 or @minus{}1 when the comparison is true
-and 0 when the comparison is false. Otherwise, the value indicates
-which bits of the result are guaranteed to be 1 when the comparison is
-true. This value is interpreted in the mode of the comparison
-operation, which is given by the mode of the first operand in the
-@samp{cstore@var{mode}4} pattern. Either the low bit or the sign bit of
-@code{STORE_FLAG_VALUE} be on. Presently, only those bits are used by
-the compiler.
-
-If @code{STORE_FLAG_VALUE} is neither 1 or @minus{}1, the compiler will
-generate code that depends only on the specified bits. It can also
-replace comparison operators with equivalent operations if they cause
-the required bits to be set, even if the remaining bits are undefined.
-For example, on a machine whose comparison operators return an
-@code{SImode} value and where @code{STORE_FLAG_VALUE} is defined as
-@samp{0x80000000}, saying that just the sign bit is relevant, the
-expression
-
-@smallexample
-(ne:SI (and:SI @var{x} (const_int @var{power-of-2})) (const_int 0))
-@end smallexample
-
-@noindent
-can be converted to
-
-@smallexample
-(ashift:SI @var{x} (const_int @var{n}))
-@end smallexample
-
-@noindent
-where @var{n} is the appropriate shift count to move the bit being
-tested into the sign bit.
-
-There is no way to describe a machine that always sets the low-order bit
-for a true value, but does not guarantee the value of any other bits,
-but we do not know of any machine that has such an instruction. If you
-are trying to port GCC to such a machine, include an instruction to
-perform a logical-and of the result with 1 in the pattern for the
-comparison operators and let us know at @email{gcc@@gcc.gnu.org}.
-
-Often, a machine will have multiple instructions that obtain a value
-from a comparison (or the condition codes). Here are rules to guide the
-choice of value for @code{STORE_FLAG_VALUE}, and hence the instructions
-to be used:
-
-@itemize @bullet
-@item
-Use the shortest sequence that yields a valid definition for
-@code{STORE_FLAG_VALUE}. It is more efficient for the compiler to
-``normalize'' the value (convert it to, e.g., 1 or 0) than for the
-comparison operators to do so because there may be opportunities to
-combine the normalization with other operations.
-
-@item
-For equal-length sequences, use a value of 1 or @minus{}1, with @minus{}1 being
-slightly preferred on machines with expensive jumps and 1 preferred on
-other machines.
-
-@item
-As a second choice, choose a value of @samp{0x80000001} if instructions
-exist that set both the sign and low-order bits but do not define the
-others.
-
-@item
-Otherwise, use a value of @samp{0x80000000}.
-@end itemize
-
-Many machines can produce both the value chosen for
-@code{STORE_FLAG_VALUE} and its negation in the same number of
-instructions. On those machines, you should also define a pattern for
-those cases, e.g., one matching
-
-@smallexample
-(set @var{A} (neg:@var{m} (ne:@var{m} @var{B} @var{C})))
-@end smallexample
-
-Some machines can also perform @code{and} or @code{plus} operations on
-condition code values with less instructions than the corresponding
-@samp{cstore@var{mode}4} insn followed by @code{and} or @code{plus}. On those
-machines, define the appropriate patterns. Use the names @code{incscc}
-and @code{decscc}, respectively, for the patterns which perform
-@code{plus} or @code{minus} operations on condition code values. See
-@file{rs6000.md} for some examples. The GNU Superoptimizer can be used to
-find such instruction sequences on other machines.
-
-If this macro is not defined, the default value, 1, is used. You need
-not define @code{STORE_FLAG_VALUE} if the machine has no store-flag
-instructions, or if the value generated by these instructions is 1.
-@end defmac
-
-@defmac FLOAT_STORE_FLAG_VALUE (@var{mode})
-A C expression that gives a nonzero @code{REAL_VALUE_TYPE} value that is
-returned when comparison operators with floating-point results are true.
-Define this macro on machines that have comparison operations that return
-floating-point values. If there are no such operations, do not define
-this macro.
-@end defmac
-
-@defmac VECTOR_STORE_FLAG_VALUE (@var{mode})
-A C expression that gives an rtx representing the nonzero true element
-for vector comparisons. The returned rtx should be valid for the inner
-mode of @var{mode} which is guaranteed to be a vector mode. Define
-this macro on machines that have vector comparison operations that
-return a vector result. If there are no such operations, do not define
-this macro. Typically, this macro is defined as @code{const1_rtx} or
-@code{constm1_rtx}. This macro may return @code{NULL_RTX} to prevent
-the compiler optimizing such vector comparison operations for the
-given mode.
-@end defmac
-
-@defmac CLZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
-@defmacx CTZ_DEFINED_VALUE_AT_ZERO (@var{mode}, @var{value})
-A C expression that indicates whether the architecture defines a value
-for @code{clz} or @code{ctz} with a zero operand.
-A result of @code{0} indicates the value is undefined.
-If the value is defined for only the RTL expression, the macro should
-evaluate to @code{1}; if the value applies also to the corresponding optab
-entry (which is normally the case if it expands directly into
-the corresponding RTL), then the macro should evaluate to @code{2}.
-In the cases where the value is defined, @var{value} should be set to
-this value.
-
-If this macro is not defined, the value of @code{clz} or
-@code{ctz} at zero is assumed to be undefined.
-
-This macro must be defined if the target's expansion for @code{ffs}
-relies on a particular value to get correct results. Otherwise it
-is not necessary, though it may be used to optimize some corner cases, and
-to provide a default expansion for the @code{ffs} optab.
-
-Note that regardless of this macro the ``definedness'' of @code{clz}
-and @code{ctz} at zero do @emph{not} extend to the builtin functions
-visible to the user. Thus one may be free to adjust the value at will
-to match the target expansion of these operations without fear of
-breaking the API@.
-@end defmac
-
-@defmac Pmode
-An alias for the machine mode for pointers. On most machines, define
-this to be the integer mode corresponding to the width of a hardware
-pointer; @code{SImode} on 32-bit machine or @code{DImode} on 64-bit machines.
-On some machines you must define this to be one of the partial integer
-modes, such as @code{PSImode}.
-
-The width of @code{Pmode} must be at least as large as the value of
-@code{POINTER_SIZE}. If it is not equal, you must define the macro
-@code{POINTERS_EXTEND_UNSIGNED} to specify how pointers are extended
-to @code{Pmode}.
-@end defmac
-
-@defmac FUNCTION_MODE
-An alias for the machine mode used for memory references to functions
-being called, in @code{call} RTL expressions. On most CISC machines,
-where an instruction can begin at any byte address, this should be
-@code{QImode}. On most RISC machines, where all instructions have fixed
-size and alignment, this should be a mode with the same size and alignment
-as the machine instruction words - typically @code{SImode} or @code{HImode}.
-@end defmac
-
-@defmac STDC_0_IN_SYSTEM_HEADERS
-In normal operation, the preprocessor expands @code{__STDC__} to the
-constant 1, to signify that GCC conforms to ISO Standard C@. On some
-hosts, like Solaris, the system compiler uses a different convention,
-where @code{__STDC__} is normally 0, but is 1 if the user specifies
-strict conformance to the C Standard.
-
-Defining @code{STDC_0_IN_SYSTEM_HEADERS} makes GNU CPP follows the host
-convention when processing system header files, but when processing user
-files @code{__STDC__} will always expand to 1.
-@end defmac
-
-@hook TARGET_C_PREINCLUDE
-
-@hook TARGET_CXX_IMPLICIT_EXTERN_C
-
-@defmac SYSTEM_IMPLICIT_EXTERN_C
-Define this macro if the system header files do not support C++@.
-This macro handles system header files by pretending that system
-header files are enclosed in @samp{extern "C" @{@dots{}@}}.
-@end defmac
-
-@findex #pragma
-@findex pragma
-@defmac REGISTER_TARGET_PRAGMAS ()
-Define this macro if you want to implement any target-specific pragmas.
-If defined, it is a C expression which makes a series of calls to
-@code{c_register_pragma} or @code{c_register_pragma_with_expansion}
-for each pragma. The macro may also do any
-setup required for the pragmas.
-
-The primary reason to define this macro is to provide compatibility with
-other compilers for the same target. In general, we discourage
-definition of target-specific pragmas for GCC@.
-
-If the pragma can be implemented by attributes then you should consider
-defining the target hook @samp{TARGET_INSERT_ATTRIBUTES} as well.
-
-Preprocessor macros that appear on pragma lines are not expanded. All
-@samp{#pragma} directives that do not match any registered pragma are
-silently ignored, unless the user specifies @option{-Wunknown-pragmas}.
-@end defmac
-
-@deftypefun void c_register_pragma (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-@deftypefunx void c_register_pragma_with_expansion (const char *@var{space}, const char *@var{name}, void (*@var{callback}) (struct cpp_reader *))
-
-Each call to @code{c_register_pragma} or
-@code{c_register_pragma_with_expansion} establishes one pragma. The
-@var{callback} routine will be called when the preprocessor encounters a
-pragma of the form
-
-@smallexample
-#pragma [@var{space}] @var{name} @dots{}
-@end smallexample
-
-@var{space} is the case-sensitive namespace of the pragma, or
-@code{NULL} to put the pragma in the global namespace. The callback
-routine receives @var{pfile} as its first argument, which can be passed
-on to cpplib's functions if necessary. You can lex tokens after the
-@var{name} by calling @code{pragma_lex}. Tokens that are not read by the
-callback will be silently ignored. The end of the line is indicated by
-a token of type @code{CPP_EOF}. Macro expansion occurs on the
-arguments of pragmas registered with
-@code{c_register_pragma_with_expansion} but not on the arguments of
-pragmas registered with @code{c_register_pragma}.
-
-Note that the use of @code{pragma_lex} is specific to the C and C++
-compilers. It will not work in the Java or Fortran compilers, or any
-other language compilers for that matter. Thus if @code{pragma_lex} is going
-to be called from target-specific code, it must only be done so when
-building the C and C++ compilers. This can be done by defining the
-variables @code{c_target_objs} and @code{cxx_target_objs} in the
-target entry in the @file{config.gcc} file. These variables should name
-the target-specific, language-specific object file which contains the
-code that uses @code{pragma_lex}. Note it will also be necessary to add a
-rule to the makefile fragment pointed to by @code{tmake_file} that shows
-how to build this object file.
-@end deftypefun
-
-@defmac HANDLE_PRAGMA_PACK_WITH_EXPANSION
-Define this macro if macros should be expanded in the
-arguments of @samp{#pragma pack}.
-@end defmac
-
-@defmac TARGET_DEFAULT_PACK_STRUCT
-If your target requires a structure packing default other than 0 (meaning
-the machine default), define this macro to the necessary value (in bytes).
-This must be a value that would also be valid to use with
-@samp{#pragma pack()} (that is, a small power of two).
-@end defmac
-
-@defmac DOLLARS_IN_IDENTIFIERS
-Define this macro to control use of the character @samp{$} in
-identifier names for the C family of languages. 0 means @samp{$} is
-not allowed by default; 1 means it is allowed. 1 is the default;
-there is no need to define this macro in that case.
-@end defmac
-
-@defmac INSN_SETS_ARE_DELAYED (@var{insn})
-Define this macro as a C expression that is nonzero if it is safe for the
-delay slot scheduler to place instructions in the delay slot of @var{insn},
-even if they appear to use a resource set or clobbered in @var{insn}.
-@var{insn} is always a @code{jump_insn} or an @code{insn}; GCC knows that
-every @code{call_insn} has this behavior. On machines where some @code{insn}
-or @code{jump_insn} is really a function call and hence has this behavior,
-you should define this macro.
-
-You need not define this macro if it would always return zero.
-@end defmac
-
-@defmac INSN_REFERENCES_ARE_DELAYED (@var{insn})
-Define this macro as a C expression that is nonzero if it is safe for the
-delay slot scheduler to place instructions in the delay slot of @var{insn},
-even if they appear to set or clobber a resource referenced in @var{insn}.
-@var{insn} is always a @code{jump_insn} or an @code{insn}. On machines where
-some @code{insn} or @code{jump_insn} is really a function call and its operands
-are registers whose use is actually in the subroutine it calls, you should
-define this macro. Doing so allows the delay slot scheduler to move
-instructions which copy arguments into the argument registers into the delay
-slot of @var{insn}.
-
-You need not define this macro if it would always return zero.
-@end defmac
-
-@defmac MULTIPLE_SYMBOL_SPACES
-Define this macro as a C expression that is nonzero if, in some cases,
-global symbols from one translation unit may not be bound to undefined
-symbols in another translation unit without user intervention. For
-instance, under Microsoft Windows symbols must be explicitly imported
-from shared libraries (DLLs).
-
-You need not define this macro if it would always evaluate to zero.
-@end defmac
-
-@hook TARGET_MD_ASM_ADJUST
-
-@defmac MATH_LIBRARY
-Define this macro as a C string constant for the linker argument to link
-in the system math library, minus the initial @samp{"-l"}, or
-@samp{""} if the target does not have a
-separate math library.
-
-You need only define this macro if the default of @samp{"m"} is wrong.
-@end defmac
-
-@defmac LIBRARY_PATH_ENV
-Define this macro as a C string constant for the environment variable that
-specifies where the linker should look for libraries.
-
-You need only define this macro if the default of @samp{"LIBRARY_PATH"}
-is wrong.
-@end defmac
-
-@defmac TARGET_POSIX_IO
-Define this macro if the target supports the following POSIX@ file
-functions, access, mkdir and file locking with fcntl / F_SETLKW@.
-Defining @code{TARGET_POSIX_IO} will enable the test coverage code
-to use file locking when exiting a program, which avoids race conditions
-if the program has forked. It will also create directories at run-time
-for cross-profiling.
-@end defmac
-
-@defmac MAX_CONDITIONAL_EXECUTE
-
-A C expression for the maximum number of instructions to execute via
-conditional execution instructions instead of a branch. A value of
-@code{BRANCH_COST}+1 is the default.
-@end defmac
-
-@defmac IFCVT_MODIFY_TESTS (@var{ce_info}, @var{true_expr}, @var{false_expr})
-Used if the target needs to perform machine-dependent modifications on the
-conditionals used for turning basic blocks into conditionally executed code.
-@var{ce_info} points to a data structure, @code{struct ce_if_block}, which
-contains information about the currently processed blocks. @var{true_expr}
-and @var{false_expr} are the tests that are used for converting the
-then-block and the else-block, respectively. Set either @var{true_expr} or
-@var{false_expr} to a null pointer if the tests cannot be converted.
-@end defmac
-
-@defmac IFCVT_MODIFY_MULTIPLE_TESTS (@var{ce_info}, @var{bb}, @var{true_expr}, @var{false_expr})
-Like @code{IFCVT_MODIFY_TESTS}, but used when converting more complicated
-if-statements into conditions combined by @code{and} and @code{or} operations.
-@var{bb} contains the basic block that contains the test that is currently
-being processed and about to be turned into a condition.
-@end defmac
-
-@defmac IFCVT_MODIFY_INSN (@var{ce_info}, @var{pattern}, @var{insn})
-A C expression to modify the @var{PATTERN} of an @var{INSN} that is to
-be converted to conditional execution format. @var{ce_info} points to
-a data structure, @code{struct ce_if_block}, which contains information
-about the currently processed blocks.
-@end defmac
-
-@defmac IFCVT_MODIFY_FINAL (@var{ce_info})
-A C expression to perform any final machine dependent modifications in
-converting code to conditional execution. The involved basic blocks
-can be found in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@defmac IFCVT_MODIFY_CANCEL (@var{ce_info})
-A C expression to cancel any machine dependent modifications in
-converting code to conditional execution. The involved basic blocks
-can be found in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@defmac IFCVT_MACHDEP_INIT (@var{ce_info})
-A C expression to initialize any machine specific data for if-conversion
-of the if-block in the @code{struct ce_if_block} structure that is pointed
-to by @var{ce_info}.
-@end defmac
-
-@hook TARGET_MACHINE_DEPENDENT_REORG
-
-@hook TARGET_INIT_BUILTINS
-
-@hook TARGET_BUILTIN_DECL
-
-@hook TARGET_EXPAND_BUILTIN
-
-@hook TARGET_RESOLVE_OVERLOADED_BUILTIN
-
-@hook TARGET_CHECK_BUILTIN_CALL
-
-@hook TARGET_FOLD_BUILTIN
-
-@hook TARGET_GIMPLE_FOLD_BUILTIN
-
-@hook TARGET_COMPARE_VERSION_PRIORITY
-
-@hook TARGET_GET_FUNCTION_VERSIONS_DISPATCHER
-
-@hook TARGET_GENERATE_VERSION_DISPATCHER_BODY
-
-@hook TARGET_PREDICT_DOLOOP_P
-
-@hook TARGET_HAVE_COUNT_REG_DECR_P
-
-@hook TARGET_DOLOOP_COST_FOR_GENERIC
-
-@hook TARGET_DOLOOP_COST_FOR_ADDRESS
-
-@hook TARGET_CAN_USE_DOLOOP_P
-
-@hook TARGET_INVALID_WITHIN_DOLOOP
-
-@hook TARGET_PREFERRED_DOLOOP_MODE
-
-@hook TARGET_LEGITIMATE_COMBINED_INSN
-
-@hook TARGET_CAN_FOLLOW_JUMP
-
-@hook TARGET_COMMUTATIVE_P
-
-@hook TARGET_ALLOCATE_INITIAL_VALUE
-
-@hook TARGET_UNSPEC_MAY_TRAP_P
-
-@hook TARGET_SET_CURRENT_FUNCTION
-
-@defmac TARGET_OBJECT_SUFFIX
-Define this macro to be a C string representing the suffix for object
-files on your target machine. If you do not define this macro, GCC will
-use @samp{.o} as the suffix for object files.
-@end defmac
-
-@defmac TARGET_EXECUTABLE_SUFFIX
-Define this macro to be a C string representing the suffix to be
-automatically added to executable files on your target machine. If you
-do not define this macro, GCC will use the null string as the suffix for
-executable files.
-@end defmac
-
-@defmac COLLECT_EXPORT_LIST
-If defined, @code{collect2} will scan the individual object files
-specified on its command line and create an export list for the linker.
-Define this macro for systems like AIX, where the linker discards
-object files that are not referenced from @code{main} and uses export
-lists.
-@end defmac
-
-@hook TARGET_CANNOT_MODIFY_JUMPS_P
-
-@hook TARGET_HAVE_CONDITIONAL_EXECUTION
-
-@hook TARGET_GEN_CCMP_FIRST
-
-@hook TARGET_GEN_CCMP_NEXT
-
-@hook TARGET_GEN_MEMSET_SCRATCH_RTX
-
-@hook TARGET_LOOP_UNROLL_ADJUST
-
-@defmac POWI_MAX_MULTS
-If defined, this macro is interpreted as a signed integer C expression
-that specifies the maximum number of floating point multiplications
-that should be emitted when expanding exponentiation by an integer
-constant inline. When this value is defined, exponentiation requiring
-more than this number of multiplications is implemented by calling the
-system library's @code{pow}, @code{powf} or @code{powl} routines.
-The default value places no upper bound on the multiplication count.
-@end defmac
-
-@deftypefn Macro void TARGET_EXTRA_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
-This target hook should register any extra include files for the
-target. The parameter @var{stdinc} indicates if normal include files
-are present. The parameter @var{sysroot} is the system root directory.
-The parameter @var{iprefix} is the prefix for the gcc directory.
-@end deftypefn
-
-@deftypefn Macro void TARGET_EXTRA_PRE_INCLUDES (const char *@var{sysroot}, const char *@var{iprefix}, int @var{stdinc})
-This target hook should register any extra include files for the
-target before any standard headers. The parameter @var{stdinc}
-indicates if normal include files are present. The parameter
-@var{sysroot} is the system root directory. The parameter
-@var{iprefix} is the prefix for the gcc directory.
-@end deftypefn
-
-@deftypefn Macro void TARGET_OPTF (char *@var{path})
-This target hook should register special include paths for the target.
-The parameter @var{path} is the include to register. On Darwin
-systems, this is used for Framework includes, which have semantics
-that are different from @option{-I}.
-@end deftypefn
-
-@defmac bool TARGET_USE_LOCAL_THUNK_ALIAS_P (tree @var{fndecl})
-This target macro returns @code{true} if it is safe to use a local alias
-for a virtual function @var{fndecl} when constructing thunks,
-@code{false} otherwise. By default, the macro returns @code{true} for all
-functions, if a target supports aliases (i.e.@: defines
-@code{ASM_OUTPUT_DEF}), @code{false} otherwise,
-@end defmac
-
-@defmac TARGET_FORMAT_TYPES
-If defined, this macro is the name of a global variable containing
-target-specific format checking information for the @option{-Wformat}
-option. The default is to have no target-specific format checks.
-@end defmac
-
-@defmac TARGET_N_FORMAT_TYPES
-If defined, this macro is the number of entries in
-@code{TARGET_FORMAT_TYPES}.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES
-If defined, this macro is the name of a global variable containing
-target-specific format overrides for the @option{-Wformat} option. The
-default is to have no target-specific format overrides. If defined,
-@code{TARGET_FORMAT_TYPES} must be defined, too.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT
-If defined, this macro specifies the number of entries in
-@code{TARGET_OVERRIDES_FORMAT_ATTRIBUTES}.
-@end defmac
-
-@defmac TARGET_OVERRIDES_FORMAT_INIT
-If defined, this macro specifies the optional initialization
-routine for target specific customizations of the system printf
-and scanf formatter settings.
-@end defmac
-
-@hook TARGET_INVALID_ARG_FOR_UNPROTOTYPED_FN
-
-@hook TARGET_INVALID_CONVERSION
-
-@hook TARGET_INVALID_UNARY_OP
-
-@hook TARGET_INVALID_BINARY_OP
-
-@hook TARGET_PROMOTED_TYPE
-
-@hook TARGET_CONVERT_TO_TYPE
-
-@hook TARGET_VERIFY_TYPE_CONTEXT
-
-@defmac OBJC_JBLEN
-This macro determines the size of the objective C jump buffer for the
-NeXT runtime. By default, OBJC_JBLEN is defined to an innocuous value.
-@end defmac
-
-@defmac LIBGCC2_UNWIND_ATTRIBUTE
-Define this macro if any target-specific attributes need to be attached
-to the functions in @file{libgcc} that provide low-level support for
-call stack unwinding. It is used in declarations in @file{unwind-generic.h}
-and the associated definitions of those functions.
-@end defmac
-
-@hook TARGET_UPDATE_STACK_BOUNDARY
-
-@hook TARGET_GET_DRAP_RTX
-
-@hook TARGET_ZERO_CALL_USED_REGS
-
-@hook TARGET_ALLOCATE_STACK_SLOTS_FOR_ARGS
-
-@hook TARGET_CONST_ANCHOR
-
-@hook TARGET_ASAN_SHADOW_OFFSET
-
-@hook TARGET_MEMMODEL_CHECK
-
-@hook TARGET_ATOMIC_TEST_AND_SET_TRUEVAL
-
-@hook TARGET_HAS_IFUNC_P
-
-@hook TARGET_IFUNC_REF_LOCAL_OK
-
-@hook TARGET_ATOMIC_ALIGN_FOR_MODE
-
-@hook TARGET_ATOMIC_ASSIGN_EXPAND_FENV
-
-@hook TARGET_RECORD_OFFLOAD_SYMBOL
-
-@hook TARGET_OFFLOAD_OPTIONS
-
-@defmac TARGET_SUPPORTS_WIDE_INT
-
-On older ports, large integers are stored in @code{CONST_DOUBLE} rtl
-objects. Newer ports define @code{TARGET_SUPPORTS_WIDE_INT} to be nonzero
-to indicate that large integers are stored in
-@code{CONST_WIDE_INT} rtl objects. The @code{CONST_WIDE_INT} allows
-very large integer constants to be represented. @code{CONST_DOUBLE}
-is limited to twice the size of the host's @code{HOST_WIDE_INT}
-representation.
-
-Converting a port mostly requires looking for the places where
-@code{CONST_DOUBLE}s are used with @code{VOIDmode} and replacing that
-code with code that accesses @code{CONST_WIDE_INT}s. @samp{"grep -i
-const_double"} at the port level gets you to 95% of the changes that
-need to be made. There are a few places that require a deeper look.
-
-@itemize @bullet
-@item
-There is no equivalent to @code{hval} and @code{lval} for
-@code{CONST_WIDE_INT}s. This would be difficult to express in the md
-language since there are a variable number of elements.
-
-Most ports only check that @code{hval} is either 0 or -1 to see if the
-value is small. As mentioned above, this will no longer be necessary
-since small constants are always @code{CONST_INT}. Of course there
-are still a few exceptions, the alpha's constraint used by the zap
-instruction certainly requires careful examination by C code.
-However, all the current code does is pass the hval and lval to C
-code, so evolving the c code to look at the @code{CONST_WIDE_INT} is
-not really a large change.
-
-@item
-Because there is no standard template that ports use to materialize
-constants, there is likely to be some futzing that is unique to each
-port in this code.
-
-@item
-The rtx costs may have to be adjusted to properly account for larger
-constants that are represented as @code{CONST_WIDE_INT}.
-@end itemize
-
-All and all it does not take long to convert ports that the
-maintainer is familiar with.
-
-@end defmac
-
-@hook TARGET_HAVE_SPECULATION_SAFE_VALUE
-
-@hook TARGET_SPECULATION_SAFE_VALUE
-
-@hook TARGET_RUN_TARGET_SELFTESTS
-
-@hook TARGET_MEMTAG_CAN_TAG_ADDRESSES
-
-@hook TARGET_MEMTAG_TAG_SIZE
-
-@hook TARGET_MEMTAG_GRANULE_SIZE
-
-@hook TARGET_MEMTAG_INSERT_RANDOM_TAG
-
-@hook TARGET_MEMTAG_ADD_TAG
-
-@hook TARGET_MEMTAG_SET_TAG
-
-@hook TARGET_MEMTAG_EXTRACT_TAG
-
-@hook TARGET_MEMTAG_UNTAGGED_POINTER
-
-@hook TARGET_GCOV_TYPE_SIZE
-
-@hook TARGET_HAVE_SHADOW_CALL_STACK
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