Properly implement STT_COMMON

The BFD configure option, --enable-elf-stt-common, can't be to used to
verify STT_COMMON implementation with the normal binutils build.  Instead,
this patch removes it from BFD.  It adds --elf-stt-common=[no|yes] to ELF
assembler/objcopy and adds -z common/-z nocommon to ld.

A configure option, --enable-elf-stt-common, is added to gas to specify
whether ELF assembler should generate common symbols with the STT_COMMON
type by default.

Since BSF_KEEP_G is never used, it is renamed to BSF_ELF_COMMON for ELF
common symbols.

bfd/

	PR ld/19645
	* bfd.c (bfd): Change flags to 20 bits.
	(BFD_CONVERT_ELF_COMMON): New.
	(BFD_USE_ELF_STT_COMMON): Likewise.
	(BFD_FLAGS_SAVED): Add BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.
	(BFD_FLAGS_FOR_BFD_USE_MASK): Likewise.
	* configure.ac: Remove --enable-elf-stt-common.
	* elf.c (swap_out_syms): Choose STT_COMMON or STT_OBJECT for
	common symbol depending on BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.
	* elfcode.h (elf_slurp_symbol_table): Set BSF_ELF_COMMON for
	STT_COMMON.
	* elflink.c (bfd_elf_link_mark_dynamic_symbol): Also check
	STT_COMMON.
	(elf_link_convert_common_type): New function.
	(elf_link_output_extsym): Choose STT_COMMON or STT_OBJECT for
	common symbol depending on BFD_CONVERT_ELF_COMMON and
	BFD_USE_ELF_STT_COMMON.  Set sym.st_info after sym.st_shndx.
	* elfxx-target.h (TARGET_BIG_SYM): Add BFD_CONVERT_ELF_COMMON
	and BFD_USE_ELF_STT_COMMON to object_flags.
	(TARGET_LITTLE_SYM): Likewise.
	* syms.c (BSF_KEEP_G): Renamed to ...
	(BSF_ELF_COMMON): This.
	* bfd-in2.h: Regenerated.
	* config.in: Likewise.
	* configure: Likewise.

binutils/

	PR ld/19645
	* NEWS: Mention --elf-stt-common= for objcopy.
	* doc/binutils.texi: Document --elf-stt-common= for objcopy.
	* objcopy.c (do_elf_stt_common): New.
	(command_line_switch): Add OPTION_ELF_STT_COMMON.
	(copy_options): Add --elf-stt-common=.
	(copy_usage): Add --elf-stt-common=.
	(copy_object): Also check do_elf_stt_common for ELF targets.
	(copy_file): Handle do_elf_stt_common.
	(copy_main): Handle OPTION_ELF_STT_COMMON.
	* readelf.c (apply_relocations): Support STT_COMMON.
	* testsuite/binutils-all/common-1.s: New file.
	* testsuite/binutils-all/common-1a.d: Likewise.
	* testsuite/binutils-all/common-1b.d: Likewise.
	* testsuite/binutils-all/common-1c.d: Likewise.
	* testsuite/binutils-all/common-1d.d: Likewise.
	* testsuite/binutils-all/common-1e.d: Likewise.
	* testsuite/binutils-all/common-1f.d: Likewise.
	* testsuite/binutils-all/common-2.s: Likewise.
	* testsuite/binutils-all/common-2a.d: Likewise.
	* testsuite/binutils-all/common-2b.d: Likewise.
	* testsuite/binutils-all/common-2c.d: Likewise.
	* testsuite/binutils-all/common-2d.d: Likewise.
	* testsuite/binutils-all/common-2e.d: Likewise.
	* testsuite/binutils-all/common-2f.d: Likewise.
	* testsuite/binutils-all/objcopy.exp
	(objcopy_test_elf_common_symbols): New proc.
	Run objcopy_test_elf_common_symbols for ELF targets

gas/

	PR ld/19645
	* NEWS: Mention --enable-elf-stt-common and --elf-stt-common=
	for ELF assemblers.
	* as.c (flag_use_elf_stt_common): New.
	(show_usage): Add --elf-stt-common=.
	(option_values): Add OPTION_ELF_STT_COMMON.
	(std_longopts): Add --elf-stt-common=.
	(parse_args): Handle --elf-stt-common=.
	* as.h (flag_use_elf_stt_common): New.
	* config.in: Regenerated.
	* configure: Likewise.
	* configure.ac: Add --enable-elf-stt-common and define
	DEFAULT_GENERATE_ELF_STT_COMMON.
	* gas/write.c (write_object_file): Set BFD_CONVERT_ELF_COMMON
	and BFD_USE_ELF_STT_COMMON if flag_use_elf_stt_common is set.
	* doc/as.texinfo: Document --elf-stt-common=.
	* testsuite/gas/elf/common3.s: New file.
	* testsuite/gas/elf/common3a.d: Likewise.
	* testsuite/gas/elf/common3b.d: Likewise.
	* testsuite/gas/elf/common4.s: Likewise.
	* testsuite/gas/elf/common4a.d: Likewise.
	* testsuite/gas/elf/common4b.d: Likewise.
	* testsuite/gas/i386/dw2-compress-3b.d: Likewise.
	* testsuite/gas/i386/dw2-compressed-3b.d: Likewise.
	* testsuite/gas/elf/elf.exp: Run common3a, common3b, common4a
	and common4b.
	* testsuite/gas/i386/dw2-compress-3.d: Renamed to ...
	* testsuite/gas/i386/dw2-compress-3a.d: This.  Pass
	--elf-stt-common=no to as.
	* testsuite/gas/i386/dw2-compressed-3.d: Renamed to ...
	* testsuite/gas/i386/dw2-compressed-3a.d: This.  Pass
	--elf-stt-common=no to as.
	* testsuite/gas/i386/i386.exp: Run dw2-compress-3a,
	dw2-compress-3b, dw2-compressed-3a and dw2-compressed-3b instead
	of dw2-compress-3 and dw2-compressed-3.

include/

	PR ld/19645
	* bfdlink.h (bfd_link_elf_stt_common): New enum.
	(bfd_link_info): Add elf_stt_common.

ld/

	PR ld/19645
	* NEWS: Mention -z common/-z nocommon for ELF targets.
	* emultempl/elf32.em (gld${EMULATION_NAME}_handle_option): Handle
	-z common and -z nocommon.
	* ld.texinfo: Document -z common/-z nocommon.
	* lexsup.c (elf_shlib_list_options): Add -z common/-z nocommon.
	* testsuite/ld-elf/tls_common.exp: Test --elf-stt-common=no and
	--elf-stt-common=yes with assembler.
	* testsuite/ld-elfcomm/common-1.s: New file.
	* testsuite/ld-elfcomm/common-1a.d: Likewise.
	* testsuite/ld-elfcomm/common-1b.d: Likewise.
	* testsuite/ld-elfcomm/common-1c.d: Likewise.
	* testsuite/ld-elfcomm/common-1d.d: Likewise.
	* testsuite/ld-elfcomm/common-1e.d: Likewise.
	* testsuite/ld-elfcomm/common-1f.d: Likewise.
	* testsuite/ld-elfcomm/common-2.s: Likewise.
	* testsuite/ld-elfcomm/common-2a.d: Likewise.
	* testsuite/ld-elfcomm/common-2b.d: Likewise.
	* testsuite/ld-elfcomm/common-2c.d: Likewise.
	* testsuite/ld-elfcomm/common-2d.d: Likewise.
	* testsuite/ld-elfcomm/common-2e.d: Likewise.
	* testsuite/ld-elfcomm/common-2f.d: Likewise.
	* testsuite/ld-elfcomm/common-3a.rd: Likewise.
	* testsuite/ld-elfcomm/common-3b.rd: Likewise.
	* testsuite/ld-i386/pr19645.d: Likewise.
	* testsuite/ld-i386/pr19645.s: Likewise.
	* testsuite/ld-x86-64/largecomm-1.s: Likewise.
	* testsuite/ld-x86-64/largecomm-1a.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1b.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1c.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1d.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1e.d: Likewise.
	* testsuite/ld-x86-64/largecomm-1f.d: Likewise.
	* testsuite/ld-x86-64/pr19645.d: Likewise.
	* testsuite/ld-x86-64/pr19645.s: Likewise.
	* testsuite/ld-elfcomm/elfcomm.exp: Test --elf-stt-common=yes
	with assembler.
	(assembler_generates_commons): Removed.
	Run -z common/-z nocommon tests.  Run *.d tests.
	* testsuite/ld-i386/i386.exp: Run pr19645.
	* testsuite/ld-x86-64/x86-64.exp: Likewise.
	* testsuite/ld-x86-64/dwarfreloc.exp: Test --elf-stt-common with
	assembler.  Test STT_COMMON with readelf.

1 files changed, 45 insertions, 6 deletions

diff --git a/binutils/objcopy.c b/binutils/objcopy.c
index 8185f28..198ba3a 100644
--- a/binutils/objcopy.c
+++ b/binutils/objcopy.c
@@ -220,6 +220,9 @@ static enum
   decompress = 1 << 4
 } do_debug_sections = nothing;
 
+/* Whether to generate ELF common symbols with the STT_COMMON type.  */
+static enum bfd_link_discard do_elf_stt_common = unchanged;
+
 /* Whether to change the leading character in symbol names.  */
 static bfd_boolean change_leading_char = FALSE;
 
@@ -294,6 +297,7 @@ enum command_line_switch
   OPTION_DEBUGGING,
   OPTION_DECOMPRESS_DEBUG_SECTIONS,
   OPTION_DUMP_SECTION,
+  OPTION_ELF_STT_COMMON,
   OPTION_EXTRACT_DWO,
   OPTION_EXTRACT_SYMBOL,
   OPTION_FILE_ALIGNMENT,
@@ -403,6 +407,7 @@ static struct option copy_options[] =
   {"discard-all", no_argument, 0, 'x'},
   {"discard-locals", no_argument, 0, 'X'},
   {"dump-section", required_argument, 0, OPTION_DUMP_SECTION},
+  {"elf-stt-common", required_argument, 0, OPTION_ELF_STT_COMMON},
   {"enable-deterministic-archives", no_argument, 0, 'D'},
   {"extract-dwo", no_argument, 0, OPTION_EXTRACT_DWO},
   {"extract-symbol", no_argument, 0, OPTION_EXTRACT_SYMBOL},
@@ -622,6 +627,8 @@ copy_usage (FILE *stream, int exit_status)
      --compress-debug-sections[={none|zlib|zlib-gnu|zlib-gabi}]\n\
                                    Compress DWARF debug sections using zlib\n\
      --decompress-debug-sections   Decompress DWARF debug sections using zlib\n\
+     --elf-stt-common=[yes|no]     Generate ELF common symbols with STT_COMMON\n\
+                                     type\n\
   -v --verbose                     List all object files modified\n\
   @<file>                          Read options from <file>\n\
   -V --version                     Display this program's version number\n\
@@ -1820,13 +1827,22 @@ copy_object (bfd *ibfd, bfd *obfd, const bfd_arch_info_type *input_arch)
       return FALSE;
     }
 
-  if ((do_debug_sections & compress) != 0
-      && do_debug_sections != compress
-      && ibfd->xvec->flavour != bfd_target_elf_flavour)
+  if (ibfd->xvec->flavour != bfd_target_elf_flavour)
     {
-      non_fatal (_("--compress-debug-sections=[zlib|zlib-gnu|zlib-gabi] is unsupported on `%s'"),
-		 bfd_get_archive_filename (ibfd));
-      return FALSE;
+      if ((do_debug_sections & compress) != 0
+	  && do_debug_sections != compress)
+	{
+	  non_fatal (_("--compress-debug-sections=[zlib|zlib-gnu|zlib-gabi] is unsupported on `%s'"),
+		     bfd_get_archive_filename (ibfd));
+	  return FALSE;
+	}
+
+      if (do_elf_stt_common)
+	{
+	  non_fatal (_("--elf-stt-common=[yes|no] is unsupported on `%s'"),
+		     bfd_get_archive_filename (ibfd));
+	  return FALSE;
+	}
     }
 
   if (verbose)
@@ -2767,6 +2783,19 @@ copy_file (const char *input_filename, const char *output_filename,
       break;
     }
 
+  switch (do_elf_stt_common)
+    {
+    case elf_stt_common:
+      ibfd->flags |= BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON;
+      break;
+      break;
+    case no_elf_stt_common:
+      ibfd->flags |= BFD_CONVERT_ELF_COMMON;
+      break;
+    default:
+      break;
+    }
+
   if (bfd_check_format (ibfd, bfd_archive))
     {
       bfd_boolean force_output_target;
@@ -4246,6 +4275,16 @@ copy_main (int argc, char *argv[])
 	  do_debug_sections = decompress;
 	  break;
 
+	case OPTION_ELF_STT_COMMON:
+	  if (strcasecmp (optarg, "yes") == 0)
+	    do_elf_stt_common = elf_stt_common;
+	  else if (strcasecmp (optarg, "no") == 0)
+	    do_elf_stt_common = no_elf_stt_common;
+	  else
+	    fatal (_("unrecognized --elf-stt-common= option `%s'"),
+		   optarg);
+	  break;
+
 	case OPTION_GAP_FILL:
 	  {
 	    bfd_vma gap_fill_vma;