This patch uses .init_array/.fini_array sections instead of .ctors/.dtors sections if mixing .init_array/.fini_array and .ctors/.dtors sections with init_priority works. It removes .ctors/.ctors sections from executables and DSOes, which will remove one function call at startup time from each executable and DSO. It should reduce image size and improve system startup time. If a platform with a working .init_array/.fini_array support needs a different .init_array/.fini_array implementation, it can set use_initfini_array to no. Since .init_array/.fini_array is a target feature. --enable-initfini-array is default to no unless the native run-time test is passed. To pass the native run-time test, a linker with SORT_BY_INIT_PRIORITY support is required. The binutils patch is available at http://sourceware.org/ml/binutils/2010-12/msg00466.html This patch passed 32bit/64bit regression test on Linux/x86-64. Thanks. H.J. --- 2010-12-14 H.J. Lu PR target/46770 * acinclude.m4 (gcc_AC_INITFINI_ARRAY): Removed. * config.gcc (use_initfini_array): New variable. Use initfini-array.o if supported. * crtstuff.c: Don't generate .ctors nor .dtors sections if NO_CTORS_DTORS_SECTIONS is defined. * configure.ac: Remove gcc_AC_INITFINI_ARRAY. Add --enable-initfini-array and check if .init_array can be used with .ctors. * configure: Regenerated. * config/initfini-array.c: New. * config/initfini-array.h: Likewise. * config/t-initfini-array: Likewise. * config/arm/arm.c (arm_asm_init_sections): Call elf_initfini_array_init_sections if NO_CTORS_DTORS_SECTIONS is defined. * config/avr/avr.c (avr_asm_init_sections): Likewise. * config/ia64/ia64.c (ia64_asm_init_sections): Likewise. * config/mep/mep.c (mep_asm_init_sections): Likewise. * config/microblaze/microblaze.c (microblaze_elf_asm_init_sections): Likewise. * config/rs6000/rs6000.c (rs6000_elf_asm_init_sections): Likewise. * config/stormy16/stormy16.c (xstormy16_asm_init_sections): Likewise. * config/v850/v850.c (v850_asm_init_sections): Likewise. diff --git a/gcc/acinclude.m4 b/gcc/acinclude.m4 index 3eec559..0f5f686 100644 --- a/gcc/acinclude.m4 +++ b/gcc/acinclude.m4 @@ -369,26 +369,6 @@ else fi fi]) -AC_DEFUN([gcc_AC_INITFINI_ARRAY], -[AC_ARG_ENABLE(initfini-array, - [ --enable-initfini-array use .init_array/.fini_array sections], - [], [ -AC_CACHE_CHECK(for .preinit_array/.init_array/.fini_array support, - gcc_cv_initfini_array, [dnl - AC_RUN_IFELSE([AC_LANG_SOURCE([ -static int x = -1; -int main (void) { return x; } -int foo (void) { x = 0; } -int (*fp) (void) __attribute__ ((section (".init_array"))) = foo;])], - [gcc_cv_initfini_array=yes], [gcc_cv_initfini_array=no], - [gcc_cv_initfini_array=no])]) - enable_initfini_array=$gcc_cv_initfini_array -]) -if test $enable_initfini_array = yes; then - AC_DEFINE(HAVE_INITFINI_ARRAY, 1, - [Define .init_array/.fini_array sections are available and working.]) -fi]) - dnl # _gcc_COMPUTE_GAS_VERSION dnl # Used by gcc_GAS_VERSION_GTE_IFELSE dnl # diff --git a/gcc/config.gcc b/gcc/config.gcc index 7c318de..7c27a9b 100644 --- a/gcc/config.gcc +++ b/gcc/config.gcc @@ -177,6 +177,9 @@ # configure_default_options # Set to an initializer for configure_default_options # in configargs.h, based on --with-cpu et cetera. +# +# use_initfini_array If set to yes, .init_array/.fini_array sections +# will be used if they work. # The following variables are used in each case-construct to build up the # outgoing variables: @@ -223,6 +226,7 @@ default_gnu_indirect_function=no target_gtfiles= need_64bit_hwint= need_64bit_isa= +use_initfini_array=yes # Don't carry these over build->host->target. Please. xm_file= @@ -3037,6 +3041,16 @@ if test x$with_schedule = x; then esac fi +# Support --enable-initfini-array. Use initfini-array.h only if +# use_initfini_array is also set to yes. Some platforms don't need it +# even if enable_initfini_array is yes. +if test x$enable_initfini_array$use_initfini_array = xyesyes; then + tm_file="${tm_file} initfini-array.h" + tmake_file="${tmake_file} t-initfini-array" + extra_objs="$extra_objs initfini-array.o" + target_gtfiles="$target_gtfiles \$(srcdir)/config/initfini-array.c" +fi + # Validate and mark as valid any --with options supported # by this target. In order to use a particular --with option # you must list it in supported_defaults; validating the value diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c index 5cf9bd0..bf8bd07 100644 --- a/gcc/config/arm/arm.c +++ b/gcc/config/arm/arm.c @@ -22881,6 +22881,9 @@ arm_asm_init_sections (void) { exception_section = get_unnamed_section (0, output_section_asm_op, "\t.handlerdata"); +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } #endif /* ARM_UNWIND_INFO */ diff --git a/gcc/config/avr/avr.c b/gcc/config/avr/avr.c index 9184d6c..bfecaf1 100644 --- a/gcc/config/avr/avr.c +++ b/gcc/config/avr/avr.c @@ -5264,6 +5264,10 @@ avr_asm_init_sections (void) NULL); readonly_data_section = data_section; +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif + data_section->unnamed.callback = avr_output_data_section_asm_op; bss_section->unnamed.callback = avr_output_bss_section_asm_op; } diff --git a/gcc/config/ia64/ia64.c b/gcc/config/ia64/ia64.c index 0512ece..873346a 100644 --- a/gcc/config/ia64/ia64.c +++ b/gcc/config/ia64/ia64.c @@ -10093,6 +10093,9 @@ ia64_asm_init_sections (void) { exception_section = get_unnamed_section (0, output_section_asm_op, "\t.handlerdata"); +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } /* Implement TARGET_DEBUG_UNWIND_INFO. */ diff --git a/gcc/config/initfini-array.c b/gcc/config/initfini-array.c new file mode 100644 index 0000000..d5fd40f --- /dev/null +++ b/gcc/config/initfini-array.c @@ -0,0 +1,79 @@ +/* Definitions for ELF systems with .init_array/.fini_array section + Copyright (C) 2010 + Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify it under +the terms of the GNU General Public License as published by the Free +Software Foundation; either version 3, or (at your option) any later +version. + +GCC is distributed in the hope that it will be useful, but WITHOUT ANY +WARRANTY; without even the implied warranty of MERCHANTABILITY or +FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License +for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +. */ + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "target.h" +#include "output.h" +#include "tree.h" +#include "ggc.h" + +static GTY(()) section *init_array_section; +static GTY(()) section *fini_array_section; + +void +elf_initfini_array_init_sections (void) +{ + init_array_section = get_unnamed_section (0, output_section_asm_op, + "\t.section\t.init_array"); + fini_array_section = get_unnamed_section (0, output_section_asm_op, + "\t.section\t.fini_array"); +} + +static section * +get_elf_initfini_array_priority_section (int priority, + bool constructor_p) +{ + section *sec; + if (priority != DEFAULT_INIT_PRIORITY) + { + char buf[18]; + sprintf (buf, "%s.%.5u", + constructor_p ? ".init_array" : ".fini_array", + priority); + sec = get_section (buf, SECTION_WRITE, NULL_TREE); + } + else + sec = constructor_p ? init_array_section : fini_array_section; + return sec; +} + +/* Use .init_array section for constructors. */ + +void +elf_init_array_asm_out_constructor (rtx symbol, int priority) +{ + section *sec = get_elf_initfini_array_priority_section (priority, + true); + assemble_addr_to_section (symbol, sec); +} + +/* Use .fini_array section for destructors. */ + +void +elf_fini_array_asm_out_destructor (rtx symbol, int priority) +{ + section *sec = get_elf_initfini_array_priority_section (priority, + false); + assemble_addr_to_section (symbol, sec); +} + +#include "gt-initfini-array.h" diff --git a/gcc/config/initfini-array.h b/gcc/config/initfini-array.h new file mode 100644 index 0000000..b0b422a --- /dev/null +++ b/gcc/config/initfini-array.h @@ -0,0 +1,46 @@ +/* Definitions for ELF systems with .init_array/.fini_array section + support. + Copyright (C) 2010 + Free Software Foundation, Inc. + + This file is part of GCC. + + GCC is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published + by the Free Software Foundation; either version 3, or (at your + option) any later version. + + GCC is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY + or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public + License for more details. + + You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING3. If not see + . */ + +/* No need for .ctors/.dtors section since linker can place them in + .init_array/.fini_array section. */ +#define NO_CTORS_DTORS_SECTIONS + +#undef INIT_SECTION_ASM_OP +#undef FINI_SECTION_ASM_OP + +/* FIXME: INIT_ARRAY_SECTION_ASM_OP and FINI_ARRAY_SECTION_ASM_OP + aren't used in any assembly codes. But we have to define + them to something. */ +#define INIT_ARRAY_SECTION_ASM_OP Something +#define FINI_ARRAY_SECTION_ASM_OP Something + +#ifndef TARGET_ASM_INIT_SECTIONS +#define TARGET_ASM_INIT_SECTIONS elf_initfini_array_init_sections +#endif +extern void elf_initfini_array_init_sections (void); + +/* Use .init_array/.fini_array section for constructors and destructors. */ +#undef TARGET_ASM_CONSTRUCTOR +#define TARGET_ASM_CONSTRUCTOR elf_init_array_asm_out_constructor +#undef TARGET_ASM_DESTRUCTOR +#define TARGET_ASM_DESTRUCTOR elf_fini_array_asm_out_destructor +extern void elf_init_array_asm_out_constructor (rtx, int); +extern void elf_fini_array_asm_out_destructor (rtx, int); diff --git a/gcc/config/mep/mep.c b/gcc/config/mep/mep.c index 60cf4eb..2c79cf9 100644 --- a/gcc/config/mep/mep.c +++ b/gcc/config/mep/mep.c @@ -7392,6 +7392,9 @@ mep_asm_init_sections (void) = get_unnamed_section (SECTION_CODE, output_section_asm_op, "\t.section .ftext,\"ax\"\n\t.core"); +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } /* Initialize the GCC target structure. */ diff --git a/gcc/config/microblaze/microblaze.c b/gcc/config/microblaze/microblaze.c index 1cec425..12c2e46 100644 --- a/gcc/config/microblaze/microblaze.c +++ b/gcc/config/microblaze/microblaze.c @@ -2751,6 +2751,9 @@ microblaze_elf_asm_init_sections (void) sdata2_section = get_unnamed_section (SECTION_WRITE, output_section_asm_op, SDATA2_SECTION_ASM_OP); +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } /* Generate assembler code for constant parts of a trampoline. */ diff --git a/gcc/config/rs6000/rs6000.c b/gcc/config/rs6000/rs6000.c index 6113a75..656c0b2 100644 --- a/gcc/config/rs6000/rs6000.c +++ b/gcc/config/rs6000/rs6000.c @@ -25415,6 +25415,10 @@ rs6000_elf_asm_init_sections (void) sdata2_section = get_unnamed_section (SECTION_WRITE, output_section_asm_op, SDATA2_SECTION_ASM_OP); + +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } /* Implement TARGET_SELECT_RTX_SECTION. */ diff --git a/gcc/config/stormy16/stormy16.c b/gcc/config/stormy16/stormy16.c index 052285c..30e5a00 100644 --- a/gcc/config/stormy16/stormy16.c +++ b/gcc/config/stormy16/stormy16.c @@ -1569,6 +1569,9 @@ xstormy16_asm_init_sections (void) = get_unnamed_section (SECTION_WRITE | SECTION_BSS, output_section_asm_op, "\t.section \".bss_below100\",\"aw\",@nobits"); +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } /* Mark symbols with the "below100" attribute so that we can use the diff --git a/gcc/config/t-initfini-array b/gcc/config/t-initfini-array new file mode 100644 index 0000000..3dcb25d --- /dev/null +++ b/gcc/config/t-initfini-array @@ -0,0 +1,23 @@ +# Copyright (C) 2010 +# 2009 Free Software Foundation, Inc. +# +# This file is part of GCC. +# +# GCC is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3, or (at your option) +# any later version. +# +# GCC is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with GCC; see the file COPYING3. If not see +# . + +initfini-array.o: $(srcdir)/config/initfini-array.c gt-initfini-array.h \ + $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TARGET_H) output.h \ + $(TREE_H) $(GGC_H) + $(COMPILER) -c $(ALL_COMPILERFLAGS) $(ALL_CPPFLAGS) $(INCLUDES) $< diff --git a/gcc/config/v850/v850.c b/gcc/config/v850/v850.c index 86509e0..4efaeaa 100644 --- a/gcc/config/v850/v850.c +++ b/gcc/config/v850/v850.c @@ -2982,6 +2982,10 @@ v850_asm_init_sections (void) = get_unnamed_section (SECTION_WRITE | SECTION_BSS, output_section_asm_op, "\t.section .zbss,\"aw\""); + +#ifdef NO_CTORS_DTORS_SECTIONS + elf_initfini_array_init_sections (); +#endif } static section * diff --git a/gcc/configure b/gcc/configure index 9056adb..d08d15a 100755 --- a/gcc/configure +++ b/gcc/configure @@ -10442,6 +10442,7 @@ fi # Restore CFLAGS from before the gcc_AC_NEED_DECLARATIONS tests. CFLAGS="$saved_CFLAGS" +# Check if .init_array can be used with .ctors. # Check whether --enable-initfini-array was given. if test "${enable_initfini_array+set}" = set; then : enableval=$enable_initfini_array; @@ -10452,16 +10453,104 @@ $as_echo_n "checking for .preinit_array/.init_array/.fini_array support... " >&6 if test "${gcc_cv_initfini_array+set}" = set; then : $as_echo_n "(cached) " >&6 else + if test "x${build}" = "x${target}" ; then if test "$cross_compiling" = yes; then : gcc_cv_initfini_array=no else cat confdefs.h - <<_ACEOF >conftest.$ac_ext /* end confdefs.h. */ -static int x = -1; -int main (void) { return x; } -int foo (void) { x = 0; } -int (*fp) (void) __attribute__ ((section (".init_array"))) = foo; +extern void abort (); +static int count; + +static void +init1005 () +{ + if (count != 0) + abort (); + count = 1005; +} +void (*const init_array1005) () + __attribute__ ((section (".init_array.01005"), aligned (sizeof (void *)))) + = { init1005 }; +static void +fini1005 () +{ + if (count != 1005) + abort (); +} +void (*const fini_array1005) () + __attribute__ ((section (".fini_array.01005"), aligned (sizeof (void *)))) + = { fini1005 }; + +static void +ctor1007 () +{ + if (count != 1005) + abort (); + count = 1007; +} +void (*const ctors1007) () + __attribute__ ((section (".ctors.64528"), aligned (sizeof (void *)))) + = { ctor1007 }; +static void +dtor1007 () +{ + if (count != 1007) + abort (); + count = 1005; +} +void (*const dtors1007) () + __attribute__ ((section (".dtors.64528"), aligned (sizeof (void *)))) + = { dtor1007 }; + +static void +init65530 () +{ + if (count != 1007) + abort (); + count = 65530; +} +void (*const init_array65530) () + __attribute__ ((section (".init_array.65530"), aligned (sizeof (void *)))) + = { init65530 }; +static void +fini65530 () +{ + if (count != 65530) + abort (); + count = 1007; +} +void (*const fini_array65530) () + __attribute__ ((section (".fini_array.65530"), aligned (sizeof (void *)))) + = { fini65530 }; + +static void +ctor65535 () +{ + if (count != 65530) + abort (); + count = 65535; +} +void (*const ctors65535) () + __attribute__ ((section (".ctors"), aligned (sizeof (void *)))) + = { ctor65535 }; +static void +dtor65535 () +{ + if (count != 65535) + abort (); + count = 65530; +} +void (*const dtors65535) () + __attribute__ ((section (".dtors"), aligned (sizeof (void *)))) + = { dtor65535 }; + +int +main () +{ + return 0; +} _ACEOF if ac_fn_c_try_run "$LINENO"; then : gcc_cv_initfini_array=yes @@ -10472,6 +10561,9 @@ rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \ conftest.$ac_objext conftest.beam conftest.$ac_ext fi + else + gcc_cv_initfini_array=no + fi fi { $as_echo "$as_me:${as_lineno-$LINENO}: result: $gcc_cv_initfini_array" >&5 $as_echo "$gcc_cv_initfini_array" >&6; } diff --git a/gcc/configure.ac b/gcc/configure.ac index eacf200..ffa4a81 100644 --- a/gcc/configure.ac +++ b/gcc/configure.ac @@ -1125,7 +1125,116 @@ fi # Restore CFLAGS from before the gcc_AC_NEED_DECLARATIONS tests. CFLAGS="$saved_CFLAGS" -gcc_AC_INITFINI_ARRAY +# Check if .init_array can be used with .ctors. +AC_ARG_ENABLE(initfini-array, + [ --enable-initfini-array use .init_array/.fini_array sections], + [], [ +AC_CACHE_CHECK(for .preinit_array/.init_array/.fini_array support, + gcc_cv_initfini_array, [dnl + if test "x${build}" = "x${target}" ; then + AC_RUN_IFELSE([AC_LANG_SOURCE([ +extern void abort (); +static int count; + +static void +init1005 () +{ + if (count != 0) + abort (); + count = 1005; +} +void (*const init_array1005[]) () + __attribute__ ((section (".init_array.01005"), aligned (sizeof (void *)))) + = { init1005 }; +static void +fini1005 () +{ + if (count != 1005) + abort (); +} +void (*const fini_array1005[]) () + __attribute__ ((section (".fini_array.01005"), aligned (sizeof (void *)))) + = { fini1005 }; + +static void +ctor1007 () +{ + if (count != 1005) + abort (); + count = 1007; +} +void (*const ctors1007[]) () + __attribute__ ((section (".ctors.64528"), aligned (sizeof (void *)))) + = { ctor1007 }; +static void +dtor1007 () +{ + if (count != 1007) + abort (); + count = 1005; +} +void (*const dtors1007[]) () + __attribute__ ((section (".dtors.64528"), aligned (sizeof (void *)))) + = { dtor1007 }; + +static void +init65530 () +{ + if (count != 1007) + abort (); + count = 65530; +} +void (*const init_array65530[]) () + __attribute__ ((section (".init_array.65530"), aligned (sizeof (void *)))) + = { init65530 }; +static void +fini65530 () +{ + if (count != 65530) + abort (); + count = 1007; +} +void (*const fini_array65530[]) () + __attribute__ ((section (".fini_array.65530"), aligned (sizeof (void *)))) + = { fini65530 }; + +static void +ctor65535 () +{ + if (count != 65530) + abort (); + count = 65535; +} +void (*const ctors65535[]) () + __attribute__ ((section (".ctors"), aligned (sizeof (void *)))) + = { ctor65535 }; +static void +dtor65535 () +{ + if (count != 65535) + abort (); + count = 65530; +} +void (*const dtors65535[]) () + __attribute__ ((section (".dtors"), aligned (sizeof (void *)))) + = { dtor65535 }; + +int +main () +{ + return 0; +}])], + [gcc_cv_initfini_array=yes], [gcc_cv_initfini_array=no], + [gcc_cv_initfini_array=no]) + else + gcc_cv_initfini_array=no + fi]) + enable_initfini_array=$gcc_cv_initfini_array +]) +if test $enable_initfini_array = yes; then + AC_DEFINE(HAVE_INITFINI_ARRAY, 1, + [Define .init_array/.fini_array sections are available and working.]) +fi # mkdir takes a single argument on some systems. gcc_AC_FUNC_MKDIR_TAKES_ONE_ARG diff --git a/gcc/crtstuff.c b/gcc/crtstuff.c index b65f490..7d31934e 100644 --- a/gcc/crtstuff.c +++ b/gcc/crtstuff.c @@ -189,6 +189,9 @@ typedef void (*func_ptr) (void); refer to only the __CTOR_END__ symbol in crtend.o and the __DTOR_LIST__ symbol in crtbegin.o, where they are defined. */ +/* No need for .ctors/.dtors section if linker can place them in + .init_array/.fini_array section. */ +#ifndef NO_CTORS_DTORS_SECTIONS /* The -1 is a flag to __do_global_[cd]tors indicating that this table does not start with a count of elements. */ #ifdef CTOR_LIST_BEGIN @@ -219,6 +222,7 @@ STATIC func_ptr __DTOR_LIST__[1] __attribute__((section(".dtors"), aligned(sizeof(func_ptr)))) = { (func_ptr) (-1) }; #endif /* __DTOR_LIST__ alternatives */ +#endif /* NO_CTORS_DTORS_SECTIONS */ #ifdef USE_EH_FRAME_REGISTRY /* Stick a label at the beginning of the frame unwind info so we can register @@ -489,6 +493,9 @@ __do_global_ctors_1(void) #elif defined(CRT_END) /* ! CRT_BEGIN */ +/* No need for .ctors/.dtors section if linker can place them in + .init_array/.fini_array section. */ +#ifndef NO_CTORS_DTORS_SECTIONS /* Put a word containing zero at the end of each of our two lists of function addresses. Note that the words defined here go into the .ctors and .dtors sections of the crtend.o file, and since that file is always linked in @@ -534,6 +541,7 @@ STATIC func_ptr __DTOR_END__[1] __attribute__((used, section(".dtors"), aligned(sizeof(func_ptr)))) = { (func_ptr) 0 }; #endif +#endif /* NO_CTORS_DTORS_SECTIONS */ #ifdef EH_FRAME_SECTION_NAME /* Terminate the frame unwind info section with a 4byte 0 as a sentinel;