* PATCH: PR c++/16276: Group jump table with function
@ 2004-07-09 19:40 H. J. Lu
2004-07-09 21:32 ` Richard Henderson
0 siblings, 1 reply; 3+ messages in thread
From: H. J. Lu @ 2004-07-09 19:40 UTC (permalink / raw)
To: gcc-patches
[-- Attachment #1: Type: text/plain, Size: 962 bytes --]
This patch tries to implement comdat group to properly fix the
second testcase in PR 16276. There are still a few issues:
1. The latest binutils is needed. The current binutils in CVS doesn't
support mixing comdat and linkonce:
http://sources.redhat.com/bugzilla/show_bug.cgi?id=246
I do have a patch to fix it. It will be tricky to check if binutils is
OK.
2. It uses string functions to convert the linkonce section name into
comdat group. The interface isn't very elegant. But its advantages are
a. Minimum change for gcc. Gcc supports more than ELF while
comdat group is ELF specific.
b. Section name is very significant in gcc. It is used for
code generation among others. Also we may have to keep
the same section naming scheme to support
__attribute__ ((section (".foo")))
Introducing a parallel section naming scheme for comdat group
may be problematic.
c. It is easy to put a section into a group by giving it the
right name.
H.J.
[-- Attachment #2: gcc-3.4-comdat-7.patch --]
[-- Type: text/plain, Size: 19023 bytes --]
2004-07-08 H.J. Lu <hongjiu.lu@intel.com>
PR c++/16276
* gcc/config/arm/arm.c (arm_elf_asm_named_section): Removed.
(arm_elf_section): New.
* config/arm/elf.h (TARGET_ASM_NAMED_SECTION): Removed.
(TARGET_ASM_ELF_SECTION): defined.
* config/sparc/sysv4.h (TARGET_ASM_NAMED_SECTION): Define only
if HAVE_GAS_COMDAT_GROUP is not defined.
* configure.ac: Check if assembler supports COMDAT group.
* configure: Regenerated.
* config.in: Likewise.
* doc/tm.texi (TARGET_ASM_NAMED_SECTION): Remove @var{align}.
(TARGET_ASM_ELF_SECTION): Documented.
* final.c (PUT_JUMP_TABLES_IN_TEXT_SECTION): New.
(shorten_branches): Replace JUMP_TABLES_IN_TEXT_SECTION with
PUT_JUMP_TABLES_IN_TEXT_SECTION.
(final_scan_insn): Likewise.
Call readonly_data_section_in_function_group instead of
readonly_data_section if HAVE_GAS_COMDAT_GROUP is defined.
* output.h (readonly_data_section_in_function_group): New
prototype.
(default_no_elf_section): Likewise.
(default_elf_section): Likewise.
* target-def.h (TARGET_ASM_ELF_SECTION): New.
(TARGET_ASM_OUT): Add TARGET_ASM_ELF_SECTION.
* target.h (asm_out): Add elf_section.
* varasm.c (readonly_data_section_in_function_group): New.
(default_no_elf_section): Likewise.
(default_elf_section): Likewise.
(elf_comdat_group): New.
(default_elf_asm_named_section): Use COMDAT group if
HAVE_GAS_COMDAT_GROUP is defined. Call
targetm.asm_out.elf_section to output section directive.
--- gcc/config.in.comdat 2004-07-09 08:17:39.883292734 -0700
+++ gcc/config.in 2004-07-09 08:17:39.964282240 -0700
@@ -252,6 +252,9 @@
/* Define if your assembler supports .balign and .p2align. */
#undef HAVE_GAS_BALIGN_AND_P2ALIGN
+/* Define 0/1 if your assembler supports COMDAT group. */
+#undef HAVE_GAS_COMDAT_GROUP
+
/* Define if your assembler uses the new HImode fild and fist notation. */
#undef HAVE_GAS_FILDS_FISTS
--- gcc/config/arm/arm.c.comdat 2004-04-30 10:36:39.000000000 -0700
+++ gcc/config/arm/arm.c 2004-07-09 09:40:32.000000000 -0700
@@ -138,7 +138,9 @@ static rtx arm_expand_unop_builtin (enum
static rtx arm_expand_builtin (tree, rtx, rtx, enum machine_mode, int);
#ifdef OBJECT_FORMAT_ELF
-static void arm_elf_asm_named_section (const char *, unsigned int);
+static void arm_elf_section (const char *, const char *,
+ const char *, int,
+ const char *, const char *);
#endif
#ifndef ARM_PE
static void arm_encode_section_info (tree, rtx, int);
@@ -13145,57 +13147,30 @@ aof_file_end (void)
#endif /* AOF_ASSEMBLER */
#ifdef OBJECT_FORMAT_ELF
-/* Switch to an arbitrary section NAME with attributes as specified
- by FLAGS. ALIGN specifies any known alignment requirements for
- the section; 0 if the default should be used.
+/* Output ELF section directive specified by NAME, FLAGS, TYPE,
+ ENTSIZE, GROUPNAME and LINKAGE in
- Differs from the default elf version only in the prefix character
- used before the section type. */
+ .section NAME,"FLAGS",%TYPE,ENTSIZE,GROUPNAME,LINKAGE
+ */
static void
-arm_elf_asm_named_section (const char *name, unsigned int flags)
-{
- char flagchars[10], *f = flagchars;
-
- if (! named_section_first_declaration (name))
- {
- fprintf (asm_out_file, "\t.section\t%s\n", name);
- return;
- }
-
- if (!(flags & SECTION_DEBUG))
- *f++ = 'a';
- if (flags & SECTION_WRITE)
- *f++ = 'w';
- if (flags & SECTION_CODE)
- *f++ = 'x';
- if (flags & SECTION_SMALL)
- *f++ = 's';
- if (flags & SECTION_MERGE)
- *f++ = 'M';
- if (flags & SECTION_STRINGS)
- *f++ = 'S';
- if (flags & SECTION_TLS)
- *f++ = 'T';
- *f = '\0';
-
- fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
-
- if (!(flags & SECTION_NOTYPE))
- {
- const char *type;
-
- if (flags & SECTION_BSS)
- type = "nobits";
- else
- type = "progbits";
-
- fprintf (asm_out_file, ",%%%s", type);
-
- if (flags & SECTION_ENTSIZE)
- fprintf (asm_out_file, ",%d", flags & SECTION_ENTSIZE);
+arm_elf_section (const char *name, const char *flags,
+ const char *type, int entsize,
+ const char *groupname, const char *linkage)
+{
+ fprintf (asm_out_file, "\t.section\t%s", name);
+ if (flags)
+ fprintf (asm_out_file, ",\"%s\"", flags);
+ if (type)
+ fprintf (asm_out_file, ",%%%s", type);
+ if (entsize)
+ fprintf (asm_out_file, ",%d", entsize);
+ if (groupname)
+ {
+ fprintf (asm_out_file, ",%s", groupname);
+ if (linkage)
+ fprintf (asm_out_file, ",%s", linkage);
}
-
putc ('\n', asm_out_file);
}
#endif
--- gcc/config/arm/elf.h.comdat 2004-02-26 13:55:16.000000000 -0800
+++ gcc/config/arm/elf.h 2004-07-09 09:26:20.000000000 -0700
@@ -117,8 +117,8 @@
#define TARGET_ASM_FILE_START_APP_OFF true
#define TARGET_ASM_FILE_START_FILE_DIRECTIVE true
\f
-#undef TARGET_ASM_NAMED_SECTION
-#define TARGET_ASM_NAMED_SECTION arm_elf_asm_named_section
+#undef TARGET_ASM_ELF_SECTION
+#define TARGET_ASM_ELF_SECTION arm_elf_section
\f
/* For PIC code we need to explicitly specify (PLT) and (GOT) relocs. */
--- gcc/config/sparc/sysv4.h.comdat 2003-06-17 17:03:32.000000000 -0700
+++ gcc/config/sparc/sysv4.h 2004-07-09 08:17:40.000000000 -0700
@@ -150,9 +150,13 @@ do { ASM_OUTPUT_ALIGN ((FILE), Pmode ==
#undef DTORS_SECTION_ASM_OP
#define DTORS_SECTION_ASM_OP "\t.section\t\".dtors\",#alloc,#write"
+/* COMDAT group cannot be expressed in SPARC's section attributes
+ encoding style. */
+#ifndef HAVE_GAS_COMDAT_GROUP
/* Switch into a generic section. */
#undef TARGET_ASM_NAMED_SECTION
#define TARGET_ASM_NAMED_SECTION sparc_elf_asm_named_section
+#endif
#undef ASM_OUTPUT_ALIGNED_BSS
#define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
--- gcc/configure.ac.comdat 2004-07-09 08:17:39.942285090 -0700
+++ gcc/configure.ac 2004-07-09 08:17:40.012276021 -0700
@@ -2070,6 +2070,13 @@ AC_DEFINE_UNQUOTED(HAVE_GAS_SHF_MERGE,
[`if test $gcc_cv_as_shf_merge = yes; then echo 1; else echo 0; fi`],
[Define 0/1 if your assembler supports marking sections with SHF_MERGE flag.])
+gcc_GAS_CHECK_FEATURE(COMDAT group support, gcc_cv_as_comdat_group,
+ [elf,2,15,91], [--fatal-warnings],
+ [.section .text,"axG",@progbits,.foo,comdat])
+AC_DEFINE_UNQUOTED(HAVE_GAS_COMDAT_GROUP,
+ [`if test $gcc_cv_as_comdat_group = yes; then echo 1; else echo 0; fi`],
+[Define 0/1 if your assembler supports COMDAT group.])
+
# Thread-local storage - the check is heavily parametrized.
conftest_s=
tls_first_major=
--- gcc/doc/tm.texi.comdat 2004-07-06 16:18:10.000000000 -0700
+++ gcc/doc/tm.texi 2004-07-09 09:03:26.740352255 -0700
@@ -6206,14 +6206,16 @@ A C statement to output something to the
macro is not defined, nothing is output for a @samp{#ident} directive.
@end defmac
-@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags}, unsigned int @var{align})
+@deftypefn {Target Hook} void TARGET_ASM_NAMED_SECTION (const char *@var{name}, unsigned int @var{flags})
Output assembly directives to switch to section @var{name}. The section
should have attributes as specified by @var{flags}, which is a bit mask
-of the @code{SECTION_*} flags defined in @file{output.h}. If @var{align}
-is nonzero, it contains an alignment in bytes to be used for the section,
-otherwise some target default should be used. Only targets that must
-specify an alignment within the section directive need pay attention to
-@var{align} -- we will still use @code{ASM_OUTPUT_ALIGN}.
+of the @code{SECTION_*} flags defined in @file{output.h}.
+@end deftypefn
+
+@deftypefn {Target Hook} void TARGET_ASM_ELF_SECTION (const char *@var{name}, const char *@var{flags}, const char *@var{type}, int @var{entsize}, const char *@var{groupname}, const char *@var{linkage})
+Output assembly ELF section directives for specified by @var{name},
+@var{flags}, @var{type}, @var{entsize}, @var{groupname} and
+@var{linkage}.
@end deftypefn
@deftypefn {Target Hook} bool TARGET_HAVE_NAMED_SECTIONS
--- gcc/final.c.comdat 2004-02-23 13:24:09.000000000 -0800
+++ gcc/final.c 2004-07-09 08:17:40.040272393 -0700
@@ -105,6 +105,13 @@ Software Foundation, 59 Temple Place - S
#define JUMP_TABLES_IN_TEXT_SECTION 0
#endif
+#ifdef HAVE_GAS_COMDAT_GROUP
+#define PUT_JUMP_TABLES_IN_TEXT_SECTION JUMP_TABLES_IN_TEXT_SECTION
+#else
+#define PUT_JUMP_TABLES_IN_TEXT_SECTION \
+ (JUMP_TABLES_IN_TEXT_SECTION || DECL_ONE_ONLY (current_function_decl))
+#endif
+
#if defined(READONLY_DATA_SECTION) || defined(READONLY_DATA_SECTION_ASM_OP)
#define HAVE_READONLY_DATA_SECTION 1
#else
@@ -835,7 +842,8 @@ shorten_branches (rtx first ATTRIBUTE_UN
next = NEXT_INSN (insn);
/* ADDR_VECs only take room if read-only data goes into the text
section. */
- if (JUMP_TABLES_IN_TEXT_SECTION || !HAVE_READONLY_DATA_SECTION)
+ if (PUT_JUMP_TABLES_IN_TEXT_SECTION
+ || !HAVE_READONLY_DATA_SECTION)
if (next && GET_CODE (next) == JUMP_INSN)
{
rtx nextbody = PATTERN (next);
@@ -998,7 +1006,8 @@ shorten_branches (rtx first ATTRIBUTE_UN
{
/* This only takes room if read-only data goes into the text
section. */
- if (JUMP_TABLES_IN_TEXT_SECTION || !HAVE_READONLY_DATA_SECTION)
+ if (PUT_JUMP_TABLES_IN_TEXT_SECTION
+ || !HAVE_READONLY_DATA_SECTION)
insn_lengths[uid] = (XVECLEN (body,
GET_CODE (body) == ADDR_DIFF_VEC)
* GET_MODE_SIZE (GET_MODE (body)));
@@ -1199,7 +1208,8 @@ shorten_branches (rtx first ATTRIBUTE_UN
PUT_MODE (body, CASE_VECTOR_SHORTEN_MODE (min_addr - rel_addr,
max_addr - rel_addr,
body));
- if (JUMP_TABLES_IN_TEXT_SECTION || !HAVE_READONLY_DATA_SECTION)
+ if (PUT_JUMP_TABLES_IN_TEXT_SECTION
+ || !HAVE_READONLY_DATA_SECTION)
{
insn_lengths[uid]
= (XVECLEN (body, 1) * GET_MODE_SIZE (GET_MODE (body)));
@@ -1877,11 +1887,16 @@ final_scan_insn (rtx insn, FILE *file, i
target, so don't output the label at all. Leave that
to the back end macros. */
#else
- if (! JUMP_TABLES_IN_TEXT_SECTION)
+ if (! PUT_JUMP_TABLES_IN_TEXT_SECTION)
{
int log_align;
+#ifdef HAVE_GAS_COMDAT_GROUP
+ readonly_data_section_in_function_group
+ (current_function_decl);
+#else
readonly_data_section ();
+#endif
#ifdef ADDR_VEC_ALIGN
log_align = ADDR_VEC_ALIGN (NEXT_INSN (insn));
--- gcc/output.h.comdat 2004-03-26 09:25:41.000000000 -0800
+++ gcc/output.h 2004-03-26 09:25:41.000000000 -0800
@@ -475,6 +475,7 @@ extern void no_asm_to_stream (FILE *);
#define SECTION_NOTYPE 0x80000 /* don't output @progbits */
#define SECTION_MACH_DEP 0x100000 /* subsequent bits reserved for target */
+extern void readonly_data_section_in_function_group (tree);
extern unsigned int get_named_section_flags (const char *);
extern bool set_named_section_flags (const char *, unsigned int);
extern void named_section_flags (const char *, unsigned int);
@@ -487,6 +488,13 @@ extern void default_elf_asm_named_sectio
extern void default_coff_asm_named_section (const char *, unsigned int);
extern void default_pe_asm_named_section (const char *, unsigned int);
+extern void default_no_elf_section (const char *, const char *,
+ const char *, int,
+ const char *, const char *);
+extern void default_elf_section (const char *, const char *,
+ const char *, int,
+ const char *, const char *);
+
extern void default_stabs_asm_out_destructor (rtx, int);
extern void default_named_section_asm_out_destructor (rtx, int);
extern void default_dtor_section_asm_out_destructor (rtx, int);
--- gcc/target-def.h.comdat 2004-03-16 08:52:57.000000000 -0800
+++ gcc/target-def.h 2004-07-09 08:51:33.337795670 -0700
@@ -124,6 +124,14 @@ Foundation, 59 Temple Place - Suite 330,
#define TARGET_HAVE_NAMED_SECTIONS false
#endif
+#ifndef TARGET_ASM_ELF_SECTION
+# ifdef OBJECT_FORMAT_ELF
+# define TARGET_ASM_ELF_SECTION default_elf_section
+# else
+# define TARGET_ASM_ELF_SECTION default_no_elf_section
+# endif
+#endif
+
#ifndef TARGET_HAVE_TLS
#define TARGET_HAVE_TLS false
#endif
@@ -196,6 +204,7 @@ Foundation, 59 Temple Place - Suite 330,
TARGET_ASM_FUNCTION_BEGIN_EPILOGUE, \
TARGET_ASM_FUNCTION_EPILOGUE, \
TARGET_ASM_NAMED_SECTION, \
+ TARGET_ASM_ELF_SECTION, \
TARGET_ASM_EXCEPTION_SECTION, \
TARGET_ASM_EH_FRAME_SECTION, \
TARGET_ASM_SELECT_SECTION, \
--- gcc/target.h.comdat 2004-03-16 08:52:57.000000000 -0800
+++ gcc/target.h 2004-07-09 09:03:44.668029169 -0700
@@ -97,6 +97,11 @@ struct gcc_target
specified by FLAGS. */
void (* named_section) (const char *, unsigned int);
+ /* Output ELF section directive specified by NAME, FLAGS, TYPE,
+ ENTSIZE, GROUPNAME and LINKAGE. */
+ void (* elf_section) (const char *, const char *, const char *,
+ int, const char *, const char *);
+
/* Switch to the section that holds the exception table. */
void (* exception_section) (void);
--- gcc/varasm.c.comdat 2004-04-16 16:59:51.000000000 -0700
+++ gcc/varasm.c 2004-04-16 16:59:51.000000000 -0700
@@ -180,6 +180,8 @@ static bool asm_emit_uninitialised (tree
unsigned HOST_WIDE_INT,
unsigned HOST_WIDE_INT);
static void mark_weak (tree);
+static const char * elf_comdat_group (const char *, const char **,
+ const char **);
\f
enum in_section { no_section, in_text, in_data, in_named
#ifdef BSS_SECTION_ASM_OP
@@ -259,6 +261,49 @@ data_section (void)
}
}
+#ifdef HAVE_GAS_COMDAT_GROUP
+
+/* Tell assembler to switch to read-only data section in the same
+ comdat group as DECL. */
+
+void
+readonly_data_section_in_function_group (tree decl)
+{
+ if (decl == NULL_TREE || !DECL_P (decl))
+ abort ();
+
+ if (DECL_SECTION_NAME (decl) == NULL_TREE
+ || ! DECL_ONE_ONLY (current_function_decl))
+ readonly_data_section ();
+ else
+#ifdef READONLY_DATA_SECTION_IN_FUNCTION_GROUP
+ READONLY_DATA_SECTION_IN_FUNCTION_GROUP (decl);
+#else
+ {
+ char *rodata;
+ const char *section_name, *group_name;
+ const char *name = TREE_STRING_POINTER (DECL_SECTION_NAME (decl));
+
+ if (!elf_comdat_group (name, §ion_name, &group_name)
+ || strcmp (section_name, ".text"))
+ abort ();
+
+ rodata = xmalloc (strlen (name) + 1);
+ rodata [sizeof (".gnu.linkonce.t") - 2] = 'r';
+ if (in_section != in_named
+ || strcmp (rodata, in_named_name) != 0)
+ {
+ in_named_name = ggc_strdup (rodata);
+ in_section = in_named;
+ (*targetm.asm_out.elf_section) (".rodata", "aG", "progbits",
+ 0, group_name, "comdat");
+ }
+ free (rodata);
+ }
+#endif
+}
+#endif
+
/* Tell assembler to switch to read-only data section. This is normally
the text section. */
@@ -4638,6 +4683,20 @@ default_section_type_flags_1 (tree decl,
return flags;
}
+/* Output ELF section directive specified by NAME, FLAGS, TYPE,
+ ENTSIZE, GROUPNAME and LINKAGE. */
+
+void
+default_no_elf_section (const char *name ATTRIBUTE_UNUSED,
+ const char *flags ATTRIBUTE_UNUSED,
+ const char *type ATTRIBUTE_UNUSED,
+ int entsize ATTRIBUTE_UNUSED,
+ const char *groupname ATTRIBUTE_UNUSED,
+ const char *linkage ATTRIBUTE_UNUSED)
+{
+ abort ();
+}
+
/* Output assembly to switch to section NAME with attribute FLAGS.
Four variants for common object file formats. */
@@ -4650,16 +4709,127 @@ default_no_named_section (const char *na
abort ();
}
+/* Output ELF section directive specified by NAME, FLAGS, TYPE,
+ ENTSIZE, GROUPNAME and LINKAGE in
+
+ .section NAME,"FLAGS",@TYPE,ENTSIZE,GROUPNAME,LINKAGE
+
+ */
+
+void
+default_elf_section (const char *name, const char *flags,
+ const char *type, int entsize,
+ const char *groupname, const char *linkage)
+{
+ fprintf (asm_out_file, "\t.section\t%s", name);
+ if (flags)
+ fprintf (asm_out_file, ",\"%s\"", flags);
+ if (type)
+ fprintf (asm_out_file, ",@%s", type);
+ if (entsize)
+ fprintf (asm_out_file, ",%d", entsize);
+ if (groupname)
+ {
+ fprintf (asm_out_file, ",%s", groupname);
+ if (linkage)
+ fprintf (asm_out_file, ",%s", linkage);
+ }
+ putc ('\n', asm_out_file);
+}
+
+/* Extract section name and group name from the linkonce section
+ name. */
+
+static const char *
+elf_comdat_group (const char *name, const char **section,
+ const char **group)
+{
+ const char *p;
+ const char *sec = NULL;
+ static const char *one [] =
+ {
+ ".bss", /* 'b' */
+ NULL, /* 'c' */
+ ".data", /* 'd' */
+ NULL, /* 'e' */
+ NULL, /* 'f' */
+ NULL, /* 'q' */
+ NULL, /* 'h' */
+ NULL, /* 'i' */
+ NULL, /* 'j' */
+ NULL, /* 'k' */
+ NULL, /* 'l' */
+ NULL, /* 'm' */
+ NULL, /* 'n' */
+ NULL, /* 'o' */
+ NULL, /* 'p' */
+ NULL, /* 'q' */
+ ".rodata", /* 'r' */
+ ".sdata", /* 's' */
+ ".text" /* 't' */
+ };
+
+ if (strncmp (name, ".gnu.linkonce.", 14) != 0)
+ return sec;
+
+ p = name + 14;
+ if (p [1] == '.')
+ {
+ if (p [0] > 'a' && p [0] < 'u')
+ sec = one [p [0] - 'b'];
+
+ if (sec)
+ *group = p + 1;
+ }
+ else if (p [2] == '.')
+ {
+ if (p [0] == 's')
+ {
+ if (p [1] == '2')
+ sec = ".sdata2";
+ else if (p [1] == 'b')
+ sec = ".sbss";
+ }
+ else if (p [0] == 't')
+ {
+ if (p [1] == 'b')
+ sec = ".tbss";
+ else if (p [1] == 'd')
+ sec = ".tdata";
+ }
+ else if (p [0] == 'w' && p [1] == 'i')
+ sec = ".debug_info";
+
+ if (sec)
+ *group = p + 2;
+ }
+ else if (strncmp (p, "sb2.", 4) == 0)
+ {
+ sec = ".sbss2";
+ *group = p + 3;
+ }
+
+ if (sec)
+ *section = sec;
+
+ return sec;
+}
+
void
default_elf_asm_named_section (const char *name, unsigned int flags)
{
char flagchars[10], *f = flagchars;
+ const char *section_name = NULL, *group_name = NULL;
+ const char *type = NULL;
+ int entsize = 0;
+#ifndef HAVE_GAS_COMDAT_GROUP
if (! named_section_first_declaration (name))
{
fprintf (asm_out_file, "\t.section\t%s\n", name);
return;
}
+#endif
if (!(flags & SECTION_DEBUG))
*f++ = 'a';
@@ -4675,26 +4845,27 @@ default_elf_asm_named_section (const cha
*f++ = 'S';
if (flags & SECTION_TLS)
*f++ = 'T';
+#ifdef HAVE_GAS_COMDAT_GROUP
+ if (elf_comdat_group (name, §ion_name, &group_name))
+ *f++ = 'G';
+#endif
*f = '\0';
- fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
+ if (section_name)
+ name = section_name;
if (!(flags & SECTION_NOTYPE))
{
- const char *type;
-
if (flags & SECTION_BSS)
type = "nobits";
else
type = "progbits";
-
- fprintf (asm_out_file, ",@%s", type);
-
- if (flags & SECTION_ENTSIZE)
- fprintf (asm_out_file, ",%d", flags & SECTION_ENTSIZE);
+
+ entsize = flags & SECTION_ENTSIZE;
}
-
- putc ('\n', asm_out_file);
+
+ (*targetm.asm_out.elf_section) (name, flagchars, type, entsize,
+ group_name, "comdat");
}
void
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: PATCH: PR c++/16276: Group jump table with function
2004-07-09 19:40 PATCH: PR c++/16276: Group jump table with function H. J. Lu
@ 2004-07-09 21:32 ` Richard Henderson
2004-07-10 7:28 ` H. J. Lu
0 siblings, 1 reply; 3+ messages in thread
From: Richard Henderson @ 2004-07-09 21:32 UTC (permalink / raw)
To: H. J. Lu; +Cc: gcc-patches
On Fri, Jul 09, 2004 at 11:31:28AM -0700, H. J. Lu wrote:
> - if (!(flags & SECTION_DEBUG))
> - *f++ = 'a';
> - if (flags & SECTION_WRITE)
> - *f++ = 'w';
> - if (flags & SECTION_CODE)
> - *f++ = 'x';
> - if (flags & SECTION_SMALL)
> - *f++ = 's';
> - if (flags & SECTION_MERGE)
> - *f++ = 'M';
> - if (flags & SECTION_STRINGS)
> - *f++ = 'S';
> - if (flags & SECTION_TLS)
> - *f++ = 'T';
> - *f = '\0';
I think you most certainly do not want to be pulling out the flags
as a string into the caller. They do not line up 100% between the
targets.
> +#ifdef HAVE_GAS_COMDAT_GROUP
> +#define PUT_JUMP_TABLES_IN_TEXT_SECTION JUMP_TABLES_IN_TEXT_SECTION
> +#else
> +#define PUT_JUMP_TABLES_IN_TEXT_SECTION \
> + (JUMP_TABLES_IN_TEXT_SECTION || DECL_ONE_ONLY (current_function_decl))
> +#endif
I think the !COMDAT case is wrong.
Suppose SUPPORTS_ONE_ONLY is false, but SUPPORTS_WEAK is true. In that
case we don't actually have to worry about what section jump tables go in.
Suppose it's a strict harvard architecture machine. In which case you
can't go putting *any* data in the text section.
I think the only workable solution is to put all the private read-only
data for a function in an rodata linkonce section for the function.
> +#ifdef READONLY_DATA_SECTION_IN_FUNCTION_GROUP
> + READONLY_DATA_SECTION_IN_FUNCTION_GROUP (decl);
> +#else
Now I think you're inventing macros that no one will ever use.
r~
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: PATCH: PR c++/16276: Group jump table with function
2004-07-09 21:32 ` Richard Henderson
@ 2004-07-10 7:28 ` H. J. Lu
0 siblings, 0 replies; 3+ messages in thread
From: H. J. Lu @ 2004-07-10 7:28 UTC (permalink / raw)
To: Richard Henderson, gcc-patches
[-- Attachment #1: Type: text/plain, Size: 1737 bytes --]
On Fri, Jul 09, 2004 at 01:54:29PM -0700, Richard Henderson wrote:
> On Fri, Jul 09, 2004 at 11:31:28AM -0700, H. J. Lu wrote:
> > - if (!(flags & SECTION_DEBUG))
> > - *f++ = 'a';
> > - if (flags & SECTION_WRITE)
> > - *f++ = 'w';
> > - if (flags & SECTION_CODE)
> > - *f++ = 'x';
> > - if (flags & SECTION_SMALL)
> > - *f++ = 's';
> > - if (flags & SECTION_MERGE)
> > - *f++ = 'M';
> > - if (flags & SECTION_STRINGS)
> > - *f++ = 'S';
> > - if (flags & SECTION_TLS)
> > - *f++ = 'T';
> > - *f = '\0';
>
> I think you most certainly do not want to be pulling out the flags
> as a string into the caller. They do not line up 100% between the
> targets.
I changed readonly_data_section_in_function_group to call
named_section_flags instead.
>
> > +#ifdef HAVE_GAS_COMDAT_GROUP
> > +#define PUT_JUMP_TABLES_IN_TEXT_SECTION JUMP_TABLES_IN_TEXT_SECTION
> > +#else
> > +#define PUT_JUMP_TABLES_IN_TEXT_SECTION \
> > + (JUMP_TABLES_IN_TEXT_SECTION || DECL_ONE_ONLY (current_function_decl))
> > +#endif
>
> I think the !COMDAT case is wrong.
>
> Suppose SUPPORTS_ONE_ONLY is false, but SUPPORTS_WEAK is true. In that
> case we don't actually have to worry about what section jump tables go in.
>
> Suppose it's a strict harvard architecture machine. In which case you
> can't go putting *any* data in the text section.
>
> I think the only workable solution is to put all the private read-only
> data for a function in an rodata linkonce section for the function.
OK.
>
> > +#ifdef READONLY_DATA_SECTION_IN_FUNCTION_GROUP
> > + READONLY_DATA_SECTION_IN_FUNCTION_GROUP (decl);
> > +#else
>
> Now I think you're inventing macros that no one will ever use.
Removed. Here is the new patch.
H.J.
[-- Attachment #2: gcc-3.4-comdat-9.patch --]
[-- Type: text/plain, Size: 8881 bytes --]
2004-07-09 H.J. Lu <hongjiu.lu@intel.com>
PR c++/16276
* configure.ac: Check if assembler supports COMDAT group.
* configure: Regenerated.
* config.in: Likewise.
* final.c (final_scan_insn): When generating jump table, call
readonly_data_section_in_function_group instead of
readonly_data_section if HAVE_GAS_COMDAT_GROUP is defined.
* output.h (elf_comdat_group): New.
(readonly_data_section_in_function_group): Likewise.
* varasm.c (readonly_data_section_in_function_group): New.
(elf_comdat_group): Likewise.
(default_elf_asm_named_section): Use COMDAT group if
HAVE_GAS_COMDAT_GROUP is defined.
* config/arm/arm.c (arm_elf_asm_named_section): Likewise.
* config/sparc/sysv4.h (TARGET_ASM_NAMED_SECTION): Define only
if HAVE_GAS_COMDAT_GROUP is not defined.
--- gcc/config.in.comdat 2004-07-09 17:37:29.000000000 -0700
+++ gcc/config.in 2004-07-09 17:37:29.000000000 -0700
@@ -252,6 +252,9 @@
/* Define if your assembler supports .balign and .p2align. */
#undef HAVE_GAS_BALIGN_AND_P2ALIGN
+/* Define 0/1 if your assembler supports COMDAT group. */
+#undef HAVE_GAS_COMDAT_GROUP
+
/* Define if your assembler uses the new HImode fild and fist notation. */
#undef HAVE_GAS_FILDS_FISTS
--- gcc/config/arm/arm.c.comdat 2004-04-30 10:36:39.000000000 -0700
+++ gcc/config/arm/arm.c 2004-07-09 17:37:29.000000000 -0700
@@ -13156,12 +13156,15 @@ static void
arm_elf_asm_named_section (const char *name, unsigned int flags)
{
char flagchars[10], *f = flagchars;
+ const char *section_name = NULL, *group_name = NULL;
+#ifndef HAVE_GAS_COMDAT_GROUP
if (! named_section_first_declaration (name))
{
fprintf (asm_out_file, "\t.section\t%s\n", name);
return;
}
+#endif
if (!(flags & SECTION_DEBUG))
*f++ = 'a';
@@ -13177,9 +13180,17 @@ arm_elf_asm_named_section (const char *n
*f++ = 'S';
if (flags & SECTION_TLS)
*f++ = 'T';
+#ifdef HAVE_GAS_COMDAT_GROUP
+ if (elf_comdat_group (name, §ion_name, &group_name))
+ *f++ = 'G';
+#endif
*f = '\0';
- fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
+ if (section_name)
+ fprintf (asm_out_file, "\t.section\t%s,\"%s\"", section_name,
+ flagchars);
+ else
+ fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
if (!(flags & SECTION_NOTYPE))
{
@@ -13196,6 +13207,9 @@ arm_elf_asm_named_section (const char *n
fprintf (asm_out_file, ",%d", flags & SECTION_ENTSIZE);
}
+ if (group_name)
+ fprintf (asm_out_file, ",%s,comdat", group_name);
+
putc ('\n', asm_out_file);
}
#endif
--- gcc/config/sparc/sysv4.h.comdat 2003-06-17 17:03:32.000000000 -0700
+++ gcc/config/sparc/sysv4.h 2004-07-09 17:37:29.000000000 -0700
@@ -150,9 +150,13 @@ do { ASM_OUTPUT_ALIGN ((FILE), Pmode ==
#undef DTORS_SECTION_ASM_OP
#define DTORS_SECTION_ASM_OP "\t.section\t\".dtors\",#alloc,#write"
+/* COMDAT group cannot be expressed in SPARC's section attributes
+ encoding style. */
+#ifndef HAVE_GAS_COMDAT_GROUP
/* Switch into a generic section. */
#undef TARGET_ASM_NAMED_SECTION
#define TARGET_ASM_NAMED_SECTION sparc_elf_asm_named_section
+#endif
#undef ASM_OUTPUT_ALIGNED_BSS
#define ASM_OUTPUT_ALIGNED_BSS(FILE, DECL, NAME, SIZE, ALIGN) \
--- gcc/configure.ac.comdat 2004-07-09 17:37:29.000000000 -0700
+++ gcc/configure.ac 2004-07-09 17:37:29.000000000 -0700
@@ -2070,6 +2070,13 @@ AC_DEFINE_UNQUOTED(HAVE_GAS_SHF_MERGE,
[`if test $gcc_cv_as_shf_merge = yes; then echo 1; else echo 0; fi`],
[Define 0/1 if your assembler supports marking sections with SHF_MERGE flag.])
+gcc_GAS_CHECK_FEATURE(COMDAT group support, gcc_cv_as_comdat_group,
+ [elf,2,15,91], [--fatal-warnings],
+ [.section .text,"axG",@progbits,.foo,comdat])
+AC_DEFINE_UNQUOTED(HAVE_GAS_COMDAT_GROUP,
+ [`if test $gcc_cv_as_comdat_group = yes; then echo 1; else echo 0; fi`],
+[Define 0/1 if your assembler supports COMDAT group.])
+
# Thread-local storage - the check is heavily parametrized.
conftest_s=
tls_first_major=
--- gcc/final.c.comdat 2004-02-23 13:24:09.000000000 -0800
+++ gcc/final.c 2004-07-09 17:38:25.000000000 -0700
@@ -1881,7 +1881,12 @@ final_scan_insn (rtx insn, FILE *file, i
{
int log_align;
+#ifdef HAVE_GAS_COMDAT_GROUP
+ readonly_data_section_in_function_group
+ (current_function_decl);
+#else
readonly_data_section ();
+#endif
#ifdef ADDR_VEC_ALIGN
log_align = ADDR_VEC_ALIGN (NEXT_INSN (insn));
--- gcc/output.h.comdat 2004-03-26 09:25:41.000000000 -0800
+++ gcc/output.h 2004-07-09 17:37:29.771404795 -0700
@@ -475,6 +475,9 @@ extern void no_asm_to_stream (FILE *);
#define SECTION_NOTYPE 0x80000 /* don't output @progbits */
#define SECTION_MACH_DEP 0x100000 /* subsequent bits reserved for target */
+extern const char *elf_comdat_group (const char *, const char **,
+ const char **);
+extern void readonly_data_section_in_function_group (tree);
extern unsigned int get_named_section_flags (const char *);
extern bool set_named_section_flags (const char *, unsigned int);
extern void named_section_flags (const char *, unsigned int);
--- gcc/varasm.c.comdat 2004-04-16 16:59:51.000000000 -0700
+++ gcc/varasm.c 2004-07-09 18:12:27.804157508 -0700
@@ -259,6 +259,35 @@ data_section (void)
}
}
+#ifdef HAVE_GAS_COMDAT_GROUP
+
+/* Tell assembler to switch to read-only data section in the same
+ comdat group as DECL. */
+
+void
+readonly_data_section_in_function_group (tree decl)
+{
+ if (decl == NULL_TREE || !DECL_P (decl))
+ abort ();
+
+ if (DECL_SECTION_NAME (decl) == NULL_TREE || ! DECL_ONE_ONLY (decl))
+ readonly_data_section ();
+ else
+ {
+ char *rodata;
+ const char *name = TREE_STRING_POINTER (DECL_SECTION_NAME (decl));
+
+ if (strncmp (name, ".gnu.linkonce.t.", 16) != 0)
+ abort ();
+
+ rodata = xstrdup (name);
+ rodata [14] = 'r';
+ named_section_flags (rodata, 0);
+ free (rodata);
+ }
+}
+#endif
+
/* Tell assembler to switch to read-only data section. This is normally
the text section. */
@@ -4650,16 +4679,97 @@ default_no_named_section (const char *na
abort ();
}
+/* Extract section name and group name from the linkonce section
+ name. */
+
+const char *
+elf_comdat_group (const char *name, const char **section,
+ const char **group)
+{
+ const char *p;
+ const char *sec = NULL;
+ static const char *one [] =
+ {
+ ".bss", /* 'b' */
+ NULL, /* 'c' */
+ ".data", /* 'd' */
+ NULL, /* 'e' */
+ NULL, /* 'f' */
+ NULL, /* 'q' */
+ NULL, /* 'h' */
+ NULL, /* 'i' */
+ NULL, /* 'j' */
+ NULL, /* 'k' */
+ NULL, /* 'l' */
+ NULL, /* 'm' */
+ NULL, /* 'n' */
+ NULL, /* 'o' */
+ NULL, /* 'p' */
+ NULL, /* 'q' */
+ ".rodata", /* 'r' */
+ ".sdata", /* 's' */
+ ".text" /* 't' */
+ };
+
+ if (strncmp (name, ".gnu.linkonce.", 14) != 0)
+ return sec;
+
+ p = name + 14;
+ if (p [1] == '.')
+ {
+ if (p [0] > 'a' && p [0] < 'u')
+ sec = one [p [0] - 'b'];
+
+ if (sec)
+ *group = p + 1;
+ }
+ else if (p [2] == '.')
+ {
+ if (p [0] == 's')
+ {
+ if (p [1] == '2')
+ sec = ".sdata2";
+ else if (p [1] == 'b')
+ sec = ".sbss";
+ }
+ else if (p [0] == 't')
+ {
+ if (p [1] == 'b')
+ sec = ".tbss";
+ else if (p [1] == 'd')
+ sec = ".tdata";
+ }
+ else if (p [0] == 'w' && p [1] == 'i')
+ sec = ".debug_info";
+
+ if (sec)
+ *group = p + 2;
+ }
+ else if (strncmp (p, "sb2.", 4) == 0)
+ {
+ sec = ".sbss2";
+ *group = p + 3;
+ }
+
+ if (sec)
+ *section = sec;
+
+ return sec;
+}
+
void
default_elf_asm_named_section (const char *name, unsigned int flags)
{
char flagchars[10], *f = flagchars;
+ const char *section_name = NULL, *group_name = NULL;
+#ifndef HAVE_GAS_COMDAT_GROUP
if (! named_section_first_declaration (name))
{
fprintf (asm_out_file, "\t.section\t%s\n", name);
return;
}
+#endif
if (!(flags & SECTION_DEBUG))
*f++ = 'a';
@@ -4675,9 +4785,17 @@ default_elf_asm_named_section (const cha
*f++ = 'S';
if (flags & SECTION_TLS)
*f++ = 'T';
+#ifdef HAVE_GAS_COMDAT_GROUP
+ if (elf_comdat_group (name, §ion_name, &group_name))
+ *f++ = 'G';
+#endif
*f = '\0';
- fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
+ if (section_name)
+ fprintf (asm_out_file, "\t.section\t%s,\"%s\"", section_name,
+ flagchars);
+ else
+ fprintf (asm_out_file, "\t.section\t%s,\"%s\"", name, flagchars);
if (!(flags & SECTION_NOTYPE))
{
@@ -4694,6 +4812,9 @@ default_elf_asm_named_section (const cha
fprintf (asm_out_file, ",%d", flags & SECTION_ENTSIZE);
}
+ if (group_name)
+ fprintf (asm_out_file, ",%s,comdat", group_name);
+
putc ('\n', asm_out_file);
}
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2004-07-10 3:55 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2004-07-09 19:40 PATCH: PR c++/16276: Group jump table with function H. J. Lu
2004-07-09 21:32 ` Richard Henderson
2004-07-10 7:28 ` H. J. Lu
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