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| author | H.J. Lu <hjl.tools@gmail.com> | 2015-05-08 05:04:12 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2015-05-08 05:05:49 -0700 |
| commit | 573cc2e57db66165b390044338d3a4ad51f36bf8 (patch) | |
| tree | d504be11ff656471087dfa0e9eae6808c2b90b3d /gas/config | |
| parent | 422349a385c2ccfc1e66f5c65560e5bd5fc97953 (diff) | |
| download | gdb-573cc2e57db66165b390044338d3a4ad51f36bf8.zip gdb-573cc2e57db66165b390044338d3a4ad51f36bf8.tar.gz gdb-573cc2e57db66165b390044338d3a4ad51f36bf8.tar.bz2 | |
Add -mno-shared to x86 assembler
On ELF target, the assembler normally generates code which can go into a
shared library where non-weak symbols can be preempted. The -mno-shared
option tells the assembler to generate code not for a shared library,
where non-weak symbols won't be preempted. The resulting code is slightly
smaller. This option mainly affects the handling of branch instructions.
gas/
* config/tc-i386.c (no_shared): New.
(OPTION_MNO_SHARED): Likewise.
(elf_symbol_resolved_in_segment_p): Check no_shared.
(md_longopts): Add mno-shared.
(md_parse_option): Handle OPTION_MNO_SHARED.
(md_show_usage): Add -mno-shared.
* doc/c-i386.texi: Document -mno-shared.
gas/testsuite/
* gas/i386/i386.exp: Run relax-4 and x86-64-relax-3.
* gas/i386/relax-4.d: New file.
* gas/i386/x86-64-relax-3.d: Likewise.
Diffstat (limited to 'gas/config')
| -rw-r--r-- | gas/config/tc-i386.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/gas/config/tc-i386.c b/gas/config/tc-i386.c index c4ba13d..bbc0969 100644 --- a/gas/config/tc-i386.c +++ b/gas/config/tc-i386.c @@ -524,6 +524,11 @@ static enum x86_elf_abi x86_elf_abi = I386_ABI; static int use_big_obj = 0; #endif +#if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) +/* 1 if not generating code for a shared library. */ +static int no_shared = 0; +#endif + /* 1 for intel syntax, 0 if att syntax. */ static int intel_syntax = 0; @@ -8785,6 +8790,10 @@ elf_symbol_resolved_in_segment_p (symbolS *fr_symbol) /* Symbol may be weak or local. */ return !S_IS_WEAK (fr_symbol); + /* Non-weak symbols won't be preempted. */ + if (no_shared) + return 1; + /* Global symbols with default visibility in a shared library may be preempted by another definition. */ return ELF_ST_VISIBILITY (S_GET_OTHER (fr_symbol)) != STV_DEFAULT; @@ -9484,6 +9493,7 @@ const char *md_shortopts = "qn"; #define OPTION_MBIG_OBJ (OPTION_MD_BASE + 18) #define OPTION_OMIT_LOCK_PREFIX (OPTION_MD_BASE + 19) #define OPTION_MEVEXRCIG (OPTION_MD_BASE + 20) +#define OPTION_MNO_SHARED (OPTION_MD_BASE + 21) struct option md_longopts[] = { @@ -9494,6 +9504,7 @@ struct option md_longopts[] = #endif #if defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) {"x32", no_argument, NULL, OPTION_X32}, + {"mno-shared", no_argument, NULL, OPTION_MNO_SHARED}, #endif {"divide", no_argument, NULL, OPTION_DIVIDE}, {"march", required_argument, NULL, OPTION_MARCH}, @@ -9554,6 +9565,10 @@ md_parse_option (int c, char *arg) /* -s: On i386 Solaris, this tells the native assembler to use .stab instead of .stab.excl. We always use .stab anyhow. */ break; + + case OPTION_MNO_SHARED: + no_shared = 1; + break; #endif #if (defined (OBJ_ELF) || defined (OBJ_MAYBE_ELF) \ || defined (TE_PE) || defined (TE_PEP) || defined (OBJ_MACH_O)) @@ -9980,6 +9995,8 @@ md_show_usage (FILE *stream) -mold-gcc support old (<= 2.8.1) versions of gcc\n")); fprintf (stream, _("\ -madd-bnd-prefix add BND prefix for all valid branches\n")); + fprintf (stream, _("\ + -mno-shared enable branch optimization for non shared code\n")); # if defined (TE_PE) || defined (TE_PEP) fprintf (stream, _("\ -mbig-obj generate big object files\n")); |