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authorH.J. Lu <hjl.tools@gmail.com>2015-05-08 05:04:12 -0700
committerH.J. Lu <hjl.tools@gmail.com>2015-05-08 05:05:49 -0700
commit573cc2e57db66165b390044338d3a4ad51f36bf8 (patch)
treed504be11ff656471087dfa0e9eae6808c2b90b3d
parent422349a385c2ccfc1e66f5c65560e5bd5fc97953 (diff)
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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.
-rw-r--r--gas/ChangeLog10
-rw-r--r--gas/config/tc-i386.c17
-rw-r--r--gas/doc/c-i386.texi10
-rw-r--r--gas/testsuite/ChangeLog6
-rw-r--r--gas/testsuite/gas/i386/i386.exp2
-rw-r--r--gas/testsuite/gas/i386/relax-4.d32
-rw-r--r--gas/testsuite/gas/i386/x86-64-relax-3.d33
7 files changed, 110 insertions, 0 deletions
diff --git a/gas/ChangeLog b/gas/ChangeLog
index 9758e72..9bf6931 100644
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,13 @@
+2015-05-08 H.J. Lu <hongjiu.lu@intel.com>
+
+ * 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.
+
2015-05-07 H.J. Lu <hongjiu.lu@intel.com>
* config/tc-i386.c (elf_symbol_resolved_in_segment_p): New.
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"));
diff --git a/gas/doc/c-i386.texi b/gas/doc/c-i386.texi
index 7f0e79f..eb6790c 100644
--- a/gas/doc/c-i386.texi
+++ b/gas/doc/c-i386.texi
@@ -297,6 +297,16 @@ The @code{.att_syntax} and @code{.intel_syntax} directives will take precedent.
This option forces the assembler to add BND prefix to all branches, even
if such prefix was not explicitly specified in the source code.
+@cindex @samp{-mno-shared} option, i386
+@cindex @samp{-mno-shared} option, x86-64
+@item -mno-shared
+On ELF target, the assembler normally generates code which can go into a
+shared library where non-weak symbols can be preempted. The
+@samp{-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.
+
@cindex @samp{-mbig-obj} option, x86-64
@item -mbig-obj
On x86-64 PE/COFF target this option forces the use of big object file
diff --git a/gas/testsuite/ChangeLog b/gas/testsuite/ChangeLog
index 1cfa577..d63f48a 100644
--- a/gas/testsuite/ChangeLog
+++ b/gas/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2015-05-08 H.J. Lu <hongjiu.lu@intel.com>
+
+ * 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.
+
2015-05-07 H.J. Lu <hongjiu.lu@intel.com>
* gas/i386/i386.exp: Run relax-3 and x86-64-relax-2.
diff --git a/gas/testsuite/gas/i386/i386.exp b/gas/testsuite/gas/i386/i386.exp
index af56c26..bedd84c 100644
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@@ -396,6 +396,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_32_check]]
run_dump_test "note"
run_dump_test "relax-3"
+ run_dump_test "relax-4"
}
# This is a PE specific test.
@@ -752,6 +753,7 @@ if [expr ([istarget "i*86-*-*"] || [istarget "x86_64-*-*"]) && [gas_64_check]] t
run_list_test "x86-64-size-inval-1" "-al"
run_dump_test "x86-64-relax-2"
+ run_dump_test "x86-64-relax-3"
}
set ASFLAGS "$old_ASFLAGS"
diff --git a/gas/testsuite/gas/i386/relax-4.d b/gas/testsuite/gas/i386/relax-4.d
new file mode 100644
index 0000000..b188841
--- /dev/null
+++ b/gas/testsuite/gas/i386/relax-4.d
@@ -0,0 +1,32 @@
+#source: relax-3.s
+#as: -mno-shared
+#objdump: -dwr
+
+.*: +file format .*
+
+Disassembly of section .text:
+
+0+ <foo>:
+[ ]*[a-f0-9]+: eb 1c jmp 1e <local>
+[ ]*[a-f0-9]+: eb 16 jmp 1a <hidden_def>
+[ ]*[a-f0-9]+: eb 16 jmp 1c <global_def>
+[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 7 <foo\+0x7> 7: (R_386_PC)?(DISP)?32 weak_def
+[ ]*[a-f0-9]+: e9 fc ff ff ff jmp c <foo\+0xc> c: (R_386_PC)?(DISP)?32 weak_hidden_undef
+[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 11 <foo\+0x11> 11: (R_386_PC)?(DISP)?32 weak_hidden_def
+[ ]*[a-f0-9]+: e9 fc ff ff ff jmp 16 <foo\+0x16> 16: (R_386_PC)?(DISP)?32 hidden_undef
+
+0+1a <hidden_def>:
+[ ]*[a-f0-9]+: c3 ret
+
+0+1b <weak_hidden_def>:
+[ ]*[a-f0-9]+: c3 ret
+
+0+1c <global_def>:
+[ ]*[a-f0-9]+: c3 ret
+
+0+1d <weak_def>:
+[ ]*[a-f0-9]+: c3 ret
+
+0+1e <local>:
+[ ]*[a-f0-9]+: c3 ret
+#pass
diff --git a/gas/testsuite/gas/i386/x86-64-relax-3.d b/gas/testsuite/gas/i386/x86-64-relax-3.d
new file mode 100644
index 0000000..d0c7ee4
--- /dev/null
+++ b/gas/testsuite/gas/i386/x86-64-relax-3.d
@@ -0,0 +1,33 @@
+#source: relax-3.s
+#as: -mno-shared
+#objdump: -dwr
+
+.*: +file format .*
+
+
+Disassembly of section .text:
+
+0+ <foo>:
+[ ]*[a-f0-9]+: eb 1c jmp 1e <local>
+[ ]*[a-f0-9]+: eb 16 jmp 1a <hidden_def>
+[ ]*[a-f0-9]+: eb 16 jmp 1c <global_def>
+[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq b <foo\+0xb> 7: R_X86_64_PC32 weak_def-0x4
+[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 10 <foo\+0x10> c: R_X86_64_PC32 weak_hidden_undef-0x4
+[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 15 <foo\+0x15> 11: R_X86_64_PC32 weak_hidden_def-0x4
+[ ]*[a-f0-9]+: e9 00 00 00 00 jmpq 1a <hidden_def> 16: R_X86_64_PC32 hidden_undef-0x4
+
+0+1a <hidden_def>:
+[ ]*[a-f0-9]+: c3 retq
+
+0+1b <weak_hidden_def>:
+[ ]*[a-f0-9]+: c3 retq
+
+0+1c <global_def>:
+[ ]*[a-f0-9]+: c3 retq
+
+0+1d <weak_def>:
+[ ]*[a-f0-9]+: c3 retq
+
+0+1e <local>:
+[ ]*[a-f0-9]+: c3 retq
+#pass