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.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 9758e72b605db67364209e4c2571c3dcd9815cce..9bf6931b4867589834fb86a65805dd6ecec39c2f 100644 (file)
--- 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 c4ba13dab4dbe47f9df505ec405bddb001261572..bbc0969da189076b04330fe03cfd9e2779f49635 100644 (file)
--- 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 7f0e79f53e2c43fab762299d42de005636a197d0..eb6790cf80ba7a2e901931e3386056577b163b80 100644 (file)
--- 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 1cfa5772151d5bea818e85829ac4f1532906ca99..d63f48a43dd2c07fad0b80d36cb7907ba5a5a8ab 100644 (file)
--- 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 af56c263991753bfad640120d274cfe4f72ad98c..bedd84c5f3237c705d0ac4a1e3767bc86dc072f0 100644 (file)
--- 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 (file)
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 (file)
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