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.
2016-02-22 09:18:52 -08:00 · 2016-02-22 09:18:52 -08:00 · b8871f357f
commit b8871f357f
parent aec6b87e0b
87 changed files with 1001 additions and 138 deletions
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@ -6378,7 +6378,9 @@ typedef struct bfd_symbol

  /* Used by the linker.  */
 #define BSF_KEEP               (1 << 5)
-#define BSF_KEEP_G             (1 << 6)
+
+  /* An ELF common symbol.  */
+#define BSF_ELF_COMMON         (1 << 6)

  /* A weak global symbol, overridable without warnings by
     a regular global symbol of the same name.  */
@ -6570,7 +6572,7 @@ struct bfd
  ENUM_BITFIELD (bfd_direction) direction : 2;

  /* Format_specific flags.  */
-  flagword flags : 18;
+  flagword flags : 20;

  /* Values that may appear in the flags field of a BFD.  These also
     appear in the object_flags field of the bfd_target structure, where
@ -6650,16 +6652,23 @@ struct bfd
  /* Compress sections in this BFD with SHF_COMPRESSED from gABI.  */
 #define BFD_COMPRESS_GABI 0x20000

+  /* Convert ELF common symbol type to STT_COMMON or STT_OBJECT in this
+     BFD.  */
+#define BFD_CONVERT_ELF_COMMON 0x40000
+
+  /* Use the ELF STT_COMMON type in this BFD.  */
+#define BFD_USE_ELF_STT_COMMON 0x80000
+
  /* Flags bits to be saved in bfd_preserve_save.  */
 #define BFD_FLAGS_SAVED \
  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_PLUGIN \
-   | BFD_COMPRESS_GABI)
+   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON)

  /* Flags bits which are for BFD use only.  */
 #define BFD_FLAGS_FOR_BFD_USE_MASK \
  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_LINKER_CREATED \
   | BFD_PLUGIN | BFD_TRADITIONAL_FORMAT | BFD_DETERMINISTIC_OUTPUT \
-   | BFD_COMPRESS_GABI)
+   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON)

  /* Is the file descriptor being cached?  That is, can it be closed as
     needed, and re-opened when accessed later?  */
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@ -91,7 +91,7 @@ CODE_FRAGMENT
 .  ENUM_BITFIELD (bfd_direction) direction : 2;
 .
 .  {* Format_specific flags.  *}
-.  flagword flags : 18;
+.  flagword flags : 20;
 .
 .  {* Values that may appear in the flags field of a BFD.  These also
 .     appear in the object_flags field of the bfd_target structure, where
@ -171,16 +171,23 @@ CODE_FRAGMENT
 .  {* Compress sections in this BFD with SHF_COMPRESSED from gABI.  *}
 .#define BFD_COMPRESS_GABI 0x20000
 .
+.  {* Convert ELF common symbol type to STT_COMMON or STT_OBJECT in this
+.     BFD.  *}
+.#define BFD_CONVERT_ELF_COMMON 0x40000
+.
+.  {* Use the ELF STT_COMMON type in this BFD.  *}
+.#define BFD_USE_ELF_STT_COMMON 0x80000
+.
 .  {* Flags bits to be saved in bfd_preserve_save.  *}
 .#define BFD_FLAGS_SAVED \
 .  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_PLUGIN \
-.   | BFD_COMPRESS_GABI)
+.   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON)
 .
 .  {* Flags bits which are for BFD use only.  *}
 .#define BFD_FLAGS_FOR_BFD_USE_MASK \
 .  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_LINKER_CREATED \
 .   | BFD_PLUGIN | BFD_TRADITIONAL_FORMAT | BFD_DETERMINISTIC_OUTPUT \
-.   | BFD_COMPRESS_GABI)
+.   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON)
 .
 .  {* Is the file descriptor being cached?  That is, can it be closed as
 .     needed, and re-opened when accessed later?  *}
--- a/bfd/config.in
+++ b/bfd/config.in
@ -349,9 +349,6 @@
 /* Define if we should default to creating read-only plt entries */
 #undef USE_SECUREPLT

-/* Define if we may generate symbols with ELF's STT_COMMON type */
-#undef USE_STT_COMMON
-
 /* Enable extensions on AIX 3, Interix.  */
 #ifndef _ALL_SOURCE
 # undef _ALL_SOURCE
--- a/bfd/configure
+++ b/bfd/configure
@ -791,7 +791,6 @@ with_mmap
 enable_secureplt
 enable_leading_mingw64_underscores
 with_separate_debug_dir
-enable_elf_stt_common
 with_pkgversion
 with_bugurl
 enable_werror
@ -1444,7 +1443,6 @@ Optional Features:
  --enable-secureplt      Default to creating read-only plt entries
  --enable-leading-mingw64-underscores
                          Enable leading underscores on 64 bit mingw targets
-  --enable-elf-stt-common Allow the generation of ELF symbols with the STT_COMMON type
  --enable-werror         treat compile warnings as errors
  --enable-build-warnings enable build-time compiler warnings
  --enable-maintainer-mode  enable make rules and dependencies not useful
@ -11423,7 +11421,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 11426 "configure"
+#line 11424 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@ -11529,7 +11527,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 11532 "configure"
+#line 11530 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@ -12175,29 +12173,6 @@ fi



-# Check to see if we should allow the generation of
-# symbols with the ELF standard's STT_COMMON type.
-# Check whether --enable-elf-stt-common was given.
-if test "${enable_elf_stt_common+set}" = set; then :
-  enableval=$enable_elf_stt_common; case "${enableval}" in
-  yes) want_elf_stt_common=true ;;
-  no)  want_elf_stt_common=false ;;
-  *)   as_fn_error "bad value ${enableval} for ELF STT_COMMON option" "$LINENO" 5 ;;
- esac
-else
-  # We have to choose a default behaviour.  For native builds we could
-# test whether the loader supports the STT_COMMON type, but that would
-# mean that built binaries could not be exported to older systems where
-# the loader does not support it. So by default we always choose to
-# disable this feature.
-  want_elf_stt_common=false
-fi
-if test $want_elf_stt_common = true; then
-
-$as_echo "#define USE_STT_COMMON 1" >>confdefs.h
-
-fi
-


 # Check whether --with-pkgversion was given.
--- a/bfd/configure.ac
+++ b/bfd/configure.ac
@ -103,26 +103,6 @@ AC_ARG_WITH(separate-debug-dir,
 [DEBUGDIR="${withval}"])
 AC_SUBST(DEBUGDIR)

-# Check to see if we should allow the generation of
-# symbols with the ELF standard's STT_COMMON type.
-AC_ARG_ENABLE(elf-stt-common,
-[  --enable-elf-stt-common Allow the generation of ELF symbols with the STT_COMMON type],
-[case "${enableval}" in
-  yes) want_elf_stt_common=true ;;
-  no)  want_elf_stt_common=false ;;
-  *)   AC_MSG_ERROR(bad value ${enableval} for ELF STT_COMMON option) ;;
- esac],
-# We have to choose a default behaviour.  For native builds we could
-# test whether the loader supports the STT_COMMON type, but that would
-# mean that built binaries could not be exported to older systems where
-# the loader does not support it. So by default we always choose to
-# disable this feature.
-  want_elf_stt_common=false)dnl
-if test $want_elf_stt_common = true; then
-  AC_DEFINE(USE_STT_COMMON, 1,
-    [Define if we may generate symbols with ELF's STT_COMMON type])
-fi
-
 ACX_PKGVERSION([GNU Binutils])
 ACX_BUGURL([http://www.sourceware.org/bugzilla/])

--- a/bfd/elf.c
+++ b/bfd/elf.c
@ -7470,12 +7470,16 @@ Unable to find equivalent output section for symbol '%s' from section '%s'"),
 	}
      else if (bfd_is_com_section (syms[idx]->section))
 	{
-#ifdef USE_STT_COMMON
-	  if (type == STT_OBJECT)
-	    sym.st_info = ELF_ST_INFO (STB_GLOBAL, STT_COMMON);
-	  else
-#endif
-	    sym.st_info = ELF_ST_INFO (STB_GLOBAL, type);
+	  if (type != STT_TLS)
+	    {
+	      if ((abfd->flags & BFD_CONVERT_ELF_COMMON))
+		type = ((abfd->flags & BFD_USE_ELF_STT_COMMON)
+			? STT_COMMON : STT_OBJECT);
+	      else
+		type = ((flags & BSF_ELF_COMMON) != 0
+			? STT_COMMON : STT_OBJECT);
+	    }
+	  sym.st_info = ELF_ST_INFO (STB_GLOBAL, type);
 	}
      else if (bfd_is_und_section (syms[idx]->section))
 	sym.st_info = ELF_ST_INFO (((flags & BSF_WEAK)
--- a/bfd/elfcode.h
+++ b/bfd/elfcode.h
@ -1302,6 +1302,7 @@ elf_slurp_symbol_table (bfd *abfd, asymbol **symptrs, bfd_boolean dynamic)
 	    case STT_COMMON:
 	      /* FIXME: Do we have to put the size field into the value field
 		 as we do with symbols in SHN_COMMON sections (see above) ?  */
+	      sym->symbol.flags |= BSF_ELF_COMMON;
 	      /* Fall through.  */
 	    case STT_OBJECT:
 	      sym->symbol.flags |= BSF_OBJECT;
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@ -525,8 +525,10 @@ bfd_elf_link_mark_dynamic_symbol (struct bfd_link_info *info,

  if ((info->dynamic_data
       && (h->type == STT_OBJECT
+	   || h->type == STT_COMMON
 	   || (sym != NULL
-	       && ELF_ST_TYPE (sym->st_info) == STT_OBJECT)))
+	       && (ELF_ST_TYPE (sym->st_info) == STT_OBJECT
+		   || ELF_ST_TYPE (sym->st_info) == STT_COMMON))))
      || (d != NULL
 	  && h->root.type == bfd_link_hash_new
 	  && (*d->match) (&d->head, NULL, h->root.root.string)))
@ -9038,6 +9040,28 @@ elf_link_check_versioned_symbol (struct bfd_link_info *info,
  return FALSE;
 }

+/* Convert ELF common symbol TYPE.  */
+
+static int
+elf_link_convert_common_type (struct bfd_link_info *info, int type)
+{
+  /* Commom symbol can only appear in relocatable link.  */
+  if (!bfd_link_relocatable (info))
+    abort ();
+  switch (info->elf_stt_common)
+    {
+    case unchanged:
+      break;
+    case elf_stt_common:
+      type = STT_COMMON;
+      break;
+    case no_elf_stt_common:
+      type = STT_OBJECT;
+      break;
+    }
+  return type;
+}
+
 /* Add an external symbol to the symbol table.  This is called from
   the hash table traversal routine.  When generating a shared object,
   we go through the symbol table twice.  The first time we output
@ -9057,6 +9081,7 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
  const struct elf_backend_data *bed;
  long indx;
  int ret;
+  unsigned int type;
  /* A symbol is bound locally if it is forced local or it is locally
     defined, hidden versioned, not referenced by shared library and
     not exported when linking executable.  */
@ -9191,35 +9216,21 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
 	   && (h->root.u.undef.abfd->flags & BFD_PLUGIN) != 0)
    strip = TRUE;

+  type = h->type;
+
  /* If we're stripping it, and it's not a dynamic symbol, there's
     nothing else to do.   However, if it is a forced local symbol or
     an ifunc symbol we need to give the backend finish_dynamic_symbol
     function a chance to make it dynamic.  */
  if (strip
      && h->dynindx == -1
-      && h->type != STT_GNU_IFUNC
+      && type != STT_GNU_IFUNC
      && !h->forced_local)
    return TRUE;

  sym.st_value = 0;
  sym.st_size = h->size;
  sym.st_other = h->other;
-  if (local_bind)
-    {
-      sym.st_info = ELF_ST_INFO (STB_LOCAL, h->type);
-      /* Turn off visibility on local symbol.  */
-      sym.st_other &= ~ELF_ST_VISIBILITY (-1);
-    }
-  /* Set STB_GNU_UNIQUE only if symbol is defined in regular object.  */
-  else if (h->unique_global && h->def_regular)
-    sym.st_info = ELF_ST_INFO (STB_GNU_UNIQUE, h->type);
-  else if (h->root.type == bfd_link_hash_undefweak
-	   || h->root.type == bfd_link_hash_defweak)
-    sym.st_info = ELF_ST_INFO (STB_WEAK, h->type);
-  else
-    sym.st_info = ELF_ST_INFO (STB_GLOBAL, h->type);
-  sym.st_target_internal = h->target_internal;
-
  switch (h->root.type)
    {
    default:
@ -9294,6 +9305,42 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
      return TRUE;
    }

+  if (type == STT_COMMON || type == STT_OBJECT)
+    switch (h->root.type)
+      {
+      case bfd_link_hash_common:
+	type = elf_link_convert_common_type (flinfo->info, type);
+	break;
+      case bfd_link_hash_defined:
+      case bfd_link_hash_defweak:
+	if (bed->common_definition (&sym))
+	  type = elf_link_convert_common_type (flinfo->info, type);
+	else
+	  type = STT_OBJECT;
+	break;
+      case bfd_link_hash_undefined:
+      case bfd_link_hash_undefweak:
+	break;
+      default:
+	abort ();
+      }
+
+  if (local_bind)
+    {
+      sym.st_info = ELF_ST_INFO (STB_LOCAL, type);
+      /* Turn off visibility on local symbol.  */
+      sym.st_other &= ~ELF_ST_VISIBILITY (-1);
+    }
+  /* Set STB_GNU_UNIQUE only if symbol is defined in regular object.  */
+  else if (h->unique_global && h->def_regular)
+    sym.st_info = ELF_ST_INFO (STB_GNU_UNIQUE, type);
+  else if (h->root.type == bfd_link_hash_undefweak
+	   || h->root.type == bfd_link_hash_defweak)
+    sym.st_info = ELF_ST_INFO (STB_WEAK, type);
+  else
+    sym.st_info = ELF_ST_INFO (STB_GLOBAL, type);
+  sym.st_target_internal = h->target_internal;
+
  /* Give the processor backend a chance to tweak the symbol value,
     and also to finish up anything that needs to be done for this
     symbol.  FIXME: Not calling elf_backend_finish_dynamic_symbol for
@ -9330,7 +9377,7 @@ elf_link_output_extsym (struct bfd_hash_entry *bh, void *data)
 	  || ELF_ST_BIND (sym.st_info) == STB_WEAK))
    {
      int bindtype;
-      unsigned int type = ELF_ST_TYPE (sym.st_info);
+      type = ELF_ST_TYPE (sym.st_info);

      /* Turn an undefined IFUNC symbol into a normal FUNC symbol. */
      if (type == STT_GNU_IFUNC)
--- a/bfd/elfxx-target.h
+++ b/bfd/elfxx-target.h
@ -850,7 +850,7 @@ const bfd_target TARGET_BIG_SYM =
  /* object_flags: mask of all file flags */
  (HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS
   | DYNAMIC | WP_TEXT | D_PAGED | BFD_COMPRESS | BFD_DECOMPRESS
-   | BFD_COMPRESS_GABI),
+   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON),

  /* section_flags: mask of all section flags */
  (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY
@ -949,7 +949,7 @@ const bfd_target TARGET_LITTLE_SYM =
  /* object_flags: mask of all file flags */
  (HAS_RELOC | EXEC_P | HAS_LINENO | HAS_DEBUG | HAS_SYMS | HAS_LOCALS
   | DYNAMIC | WP_TEXT | D_PAGED | BFD_COMPRESS | BFD_DECOMPRESS
-   | BFD_COMPRESS_GABI),
+   | BFD_COMPRESS_GABI | BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON),

  /* section_flags: mask of all section flags */
  (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_LOAD | SEC_RELOC | SEC_READONLY
--- a/bfd/syms.c
+++ b/bfd/syms.c
@ -231,7 +231,9 @@ CODE_FRAGMENT
 .
 .  {* Used by the linker.  *}
 .#define BSF_KEEP		(1 << 5)
-.#define BSF_KEEP_G		(1 << 6)
+.
+.  {* An ELF common symbol.  *}
+.#define BSF_ELF_COMMON		(1 << 6)
 .
 .  {* A weak global symbol, overridable without warnings by
 .     a regular global symbol of the same name.  *}
--- a/binutils/NEWS
+++ b/binutils/NEWS
@ -1,5 +1,8 @@
 -*- text -*-

+* Add --elf-stt-common= option to objcopy for ELF targets to control
+  whether to convert common symbols to the STT_COMMON type.
+
 Changes in 2.26:

 * Add option to objcopy to insert new symbols into a file:
--- a/binutils/doc/binutils.texi
+++ b/binutils/doc/binutils.texi
@ -1131,6 +1131,7 @@ objcopy [@option{-F} @var{bfdname}|@option{--target=}@var{bfdname}]
        [@option{--decompress-debug-sections}]
        [@option{--dwarf-depth=@var{n}}]
        [@option{--dwarf-start=@var{n}}]
+        [@option{--elf-stt-common=@var{val}}]
        [@option{-v}|@option{--verbose}]
        [@option{-V}|@option{--version}]
        [@option{--help}] [@option{--info}]
@ -1886,6 +1887,14 @@ renamed.
 Decompress DWARF debug sections using zlib.  The original section
 names of the compressed sections are restored.

+@item --elf-stt-common=yes
+@itemx --elf-stt-common=no
+For ELF files, these options control whether common symbols should be
+converted to the @code{STT_COMMON} or @code{STT_OBJECT} type.
+@option{--elf-stt-common=yes} converts common symbol type to
+@code{STT_COMMON}. @option{--elf-stt-common=no} converts common symbol
+type to @code{STT_OBJECT}.
+
@item -V
@itemx --version
 Show the version number of @command{objcopy}.
--- 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;
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@ -11982,6 +11982,7 @@ apply_relocations (void *                     file,
 	     referencing a global array.  For an example of this see
 	     the _clz.o binary in libgcc.a.  */
 	  if (sym != symtab
+	      && ELF_ST_TYPE (sym->st_info) != STT_COMMON
 	      && ELF_ST_TYPE (sym->st_info) > STT_SECTION)
 	    {
 	      warn (_("skipping unexpected symbol type %s in %ld'th relocation in section %s\n"),
--- a/binutils/testsuite/binutils-all/common-1.s
+++ b/binutils/testsuite/binutils-all/common-1.s
@ -0,0 +1 @@
+	.comm foobar,30,4
--- a/binutils/testsuite/binutils-all/common-1a.d
+++ b/binutils/testsuite/binutils-all/common-1a.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-1b.d
+++ b/binutils/testsuite/binutils-all/common-1b.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-1c.d
+++ b/binutils/testsuite/binutils-all/common-1c.d
@ -0,0 +1,9 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#objcopy: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-1d.d
+++ b/binutils/testsuite/binutils-all/common-1d.d
@ -0,0 +1,9 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#objcopy: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-1e.d
+++ b/binutils/testsuite/binutils-all/common-1e.d
@ -0,0 +1,9 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#objcopy: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-1f.d
+++ b/binutils/testsuite/binutils-all/common-1f.d
@ -0,0 +1,9 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#objcopy: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2.s
+++ b/binutils/testsuite/binutils-all/common-2.s
@ -0,0 +1 @@
+	.tls_common foobar,30,4
--- a/binutils/testsuite/binutils-all/common-2a.d
+++ b/binutils/testsuite/binutils-all/common-2a.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2b.d
+++ b/binutils/testsuite/binutils-all/common-2b.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2c.d
+++ b/binutils/testsuite/binutils-all/common-2c.d
@ -0,0 +1,9 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#objcopy: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2d.d
+++ b/binutils/testsuite/binutils-all/common-2d.d
@ -0,0 +1,9 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#PROG: objcopy
+#objcopy: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2e.d
+++ b/binutils/testsuite/binutils-all/common-2e.d
@ -0,0 +1,9 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#objcopy: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/common-2f.d
+++ b/binutils/testsuite/binutils-all/common-2f.d
@ -0,0 +1,9 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#PROG: objcopy
+#objcopy: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/binutils/testsuite/binutils-all/objcopy.exp
+++ b/binutils/testsuite/binutils-all/objcopy.exp
@ -1005,6 +1005,23 @@ proc objcopy_test_symbol_manipulation {} {
    }
 }

+proc objcopy_test_elf_common_symbols {} {
+    global srcdir
+    global subdir
+
+    # hpux has a non-standard common directive.
+    if { [istarget "*-*-hpux*"] } then {
+	return
+    }
+
+    set test_list [lsort [glob -nocomplain $srcdir/$subdir/common-*.d]]
+    foreach t $test_list {
+        # We need to strip the ".d", but can leave the dirname.
+        verbose [file rootname $t]
+        run_dump_test [file rootname $t]
+    }
+}
+
 # ia64 specific tests
 if { ([istarget "ia64-*-elf*"]
       || [istarget "ia64-*-linux*"]) } {
@ -1014,6 +1031,7 @@ if { ([istarget "ia64-*-elf*"]
 # ELF specific tests
 if [is_elf_format] {
    objcopy_test_symbol_manipulation
+    objcopy_test_elf_common_symbols
    objcopy_test "ELF unknown section type" unknown.s
    objcopy_test_readelf "ELF group" group.s
    objcopy_test_readelf "ELF group" group-2.s
--- a/gas/NEWS
+++ b/gas/NEWS
@ -1,4 +1,11 @@
 -*- text -*-
+* Add a configure option --enable-elf-stt-common to decide whether ELF
+  assembler should generate common symbols with the STT_COMMON type by
+  default.  Default to no.
+
+* New command line option --elf-stt-common= for ELF targets to control
+  whether to generate common symbols with the STT_COMMON type.
+
 * Add ability to set section flags and types via numeric values for ELF
  based targets.

--- a/gas/as.c
+++ b/gas/as.c
@ -96,6 +96,10 @@ int debug_memory = 0;
 /* Enable verbose mode.  */
 int verbose = 0;

+#if defined OBJ_ELF || defined OBJ_MAYBE_ELF
+int flag_use_elf_stt_common = DEFAULT_GENERATE_ELF_STT_COMMON;
+#endif
+
 /* Keep the output file.  */
 static int keep_it = 0;

@ -300,6 +304,9 @@ Options:\n\
  --size-check=[error|warning]\n\
 			  ELF .size directive check (default --size-check=error)\n"));
  fprintf (stream, _("\
+  --elf-stt-common=[no|yes]\n\
+                          generate ELF common symbols with STT_COMMON type\n"));
+  fprintf (stream, _("\
  --sectname-subst        enable section name substitution sequences\n"));
 #endif
  fprintf (stream, _("\
@ -464,6 +471,7 @@ parse_args (int * pargc, char *** pargv)
      OPTION_EXECSTACK,
      OPTION_NOEXECSTACK,
      OPTION_SIZE_CHECK,
+      OPTION_ELF_STT_COMMON,
      OPTION_SECTNAME_SUBST,
      OPTION_ALTERNATE,
      OPTION_AL,
@ -499,6 +507,7 @@ parse_args (int * pargc, char *** pargv)
    ,{"execstack", no_argument, NULL, OPTION_EXECSTACK}
    ,{"noexecstack", no_argument, NULL, OPTION_NOEXECSTACK}
    ,{"size-check", required_argument, NULL, OPTION_SIZE_CHECK}
+    ,{"elf-stt-common", required_argument, NULL, OPTION_ELF_STT_COMMON}
    ,{"sectname-subst", no_argument, NULL, OPTION_SECTNAME_SUBST}
 #endif
    ,{"fatal-warnings", no_argument, NULL, OPTION_WARN_FATAL}
@ -868,6 +877,16 @@ This program has absolutely no warranty.\n"));
 	    as_fatal (_("Invalid --size-check= option: `%s'"), optarg);
 	  break;

+	case OPTION_ELF_STT_COMMON:
+	  if (strcasecmp (optarg, "no") == 0)
+	    flag_use_elf_stt_common = 0;
+	  else if (strcasecmp (optarg, "yes") == 0)
+	    flag_use_elf_stt_common = 1;
+	  else
+	    as_fatal (_("Invalid --elf-stt-common= option: `%s'"),
+		      optarg);
+	  break;
+
 	case OPTION_SECTNAME_SUBST:
 	  flag_sectname_subst = 1;
 	  break;
--- a/gas/as.h
+++ b/gas/as.h
@ -592,6 +592,9 @@ COMMON enum
  }
 flag_size_check;

+/* If we should generate ELF common symbols with the STT_COMMON type.  */
+extern int flag_use_elf_stt_common;
+
 /* If section name substitution sequences should be honored */
 COMMON int flag_sectname_subst;
 #endif
--- a/gas/config.in
+++ b/gas/config.in
@ -39,6 +39,10 @@
 /* Define if you want compressed debug sections by default. */
 #undef DEFAULT_FLAG_COMPRESS_DEBUG

+/* Define to 1 if you want to generate ELF common symbols with the STT_COMMON
+   type by default. */
+#undef DEFAULT_GENERATE_ELF_STT_COMMON
+
 /* Define to 1 if you want to generate x86 relax relocations by default. */
 #undef DEFAULT_GENERATE_X86_RELAX_RELOCATIONS

--- a/gas/configure
+++ b/gas/configure
@ -766,6 +766,7 @@ enable_targets
 enable_checking
 enable_compressed_debug_sections
 enable_x86_relax_relocations
+enable_elf_stt_common
 enable_werror
 enable_build_warnings
 enable_nls
@ -1418,6 +1419,8 @@ Optional Features:
                          compress debug sections by default
  --enable-x86-relax-relocations
                          generate x86 relax relocations by default
+  --enable-elf-stt-common generate ELF common symbols with STT_COMMON type by
+                          default
  --enable-werror         treat compile warnings as errors
  --enable-build-warnings enable build-time compiler warnings
  --disable-nls           do not use Native Language Support
@ -10975,7 +10978,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 10978 "configure"
+#line 10981 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@ -11081,7 +11084,7 @@ else
  lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
  lt_status=$lt_dlunknown
  cat > conftest.$ac_ext <<_LT_EOF
-#line 11084 "configure"
+#line 11087 "configure"
 #include "confdefs.h"

 #if HAVE_DLFCN_H
@ -11694,6 +11697,17 @@ if test "${enable_x86_relax_relocations+set}" = set; then :
 esac
 fi

+# Decide if ELF assembler should generate common symbols with the
+# STT_COMMON type.
+ac_default_elf_stt_common=unset
+# Provide a configure time option to override our default.
+# Check whether --enable-elf_stt_common was given.
+if test "${enable_elf_stt_common+set}" = set; then :
+  enableval=$enable_elf_stt_common; case "${enableval}" in
+  yes)  ac_default_elf_stt_common=1 ;;
+esac
+fi
+
 using_cgen=no


@ -12539,6 +12553,15 @@ cat >>confdefs.h <<_ACEOF
 _ACEOF


+if test ${ac_default_elf_stt_common} = unset; then
+  ac_default_elf_stt_common=0
+fi
+
+cat >>confdefs.h <<_ACEOF
+#define DEFAULT_GENERATE_ELF_STT_COMMON $ac_default_elf_stt_common
+_ACEOF
+
+
 if test x$ac_default_compressed_debug_sections = xyes ; then

 $as_echo "#define DEFAULT_FLAG_COMPRESS_DEBUG 1" >>confdefs.h
--- a/gas/configure.ac
+++ b/gas/configure.ac
@ -88,6 +88,17 @@ AC_ARG_ENABLE(x86_relax_relocations,
  no)  ac_default_x86_relax_relocations=0 ;;
 esac])dnl

+# Decide if ELF assembler should generate common symbols with the
+# STT_COMMON type.
+ac_default_elf_stt_common=unset
+# Provide a configure time option to override our default.
+AC_ARG_ENABLE(elf_stt_common,
+	      AS_HELP_STRING([--enable-elf-stt-common],
+	      [generate ELF common symbols with STT_COMMON type by default]),
+[case "${enableval}" in
+  yes)  ac_default_elf_stt_common=1 ;;
+esac])dnl
+
 using_cgen=no

 AM_BINUTILS_WARNINGS
@ -578,6 +589,14 @@ AC_DEFINE_UNQUOTED(DEFAULT_GENERATE_X86_RELAX_RELOCATIONS,
  $ac_default_x86_relax_relocations,
  [Define to 1 if you want to generate x86 relax relocations by default.])

+if test ${ac_default_elf_stt_common} = unset; then
+  ac_default_elf_stt_common=0
+fi
+AC_DEFINE_UNQUOTED(DEFAULT_GENERATE_ELF_STT_COMMON,
+  $ac_default_elf_stt_common,
+  [Define to 1 if you want to generate ELF common symbols with the
+   STT_COMMON type by default.])
+
 if test x$ac_default_compressed_debug_sections = xyes ; then
  AC_DEFINE(DEFAULT_FLAG_COMPRESS_DEBUG, 1, [Define if you want compressed debug sections by default.])
 fi
--- a/gas/doc/as.texinfo
+++ b/gas/doc/as.texinfo
@ -242,6 +242,7 @@ gcc(1), ld(1), and the Info entries for @file{binutils} and @file{ld}.
 [@b{-W}] [@b{--warn}] [@b{--fatal-warnings}] [@b{-w}] [@b{-x}]
 [@b{-Z}] [@b{@@@var{FILE}}]
 [@b{--sectname-subst}] [@b{--size-check=[error|warning]}]
+ [@b{--elf-stt-common=[no|yes]}]
 [@b{--target-help}] [@var{target-options}]
 [@b{--}|@var{files} @dots{}]
@c
@ -712,10 +713,18 @@ will have its dwarf line number information placed into a section called
 then debug line section will still be called just @var{.debug_line} without any
 suffix.

+@ifset ELF
@item --size-check=error
@itemx --size-check=warning
 Issue an error or warning for invalid ELF .size directive.

+@item --elf-stt-common=no
+@itemx --elf-stt-common=yes
+These options control whether the ELF assembler should generate common
+symbols with the @code{STT_COMMON} type.  The default can be controlled
+by a configure option @option{--enable-elf-stt-common}.
+@end ifset
+
@item --help
 Print a summary of the command line options and exit.

--- a/gas/testsuite/gas/elf/common3.s
+++ b/gas/testsuite/gas/elf/common3.s
@ -0,0 +1 @@
+	.comm foobar,30,4
--- a/gas/testsuite/gas/elf/common3a.d
+++ b/gas/testsuite/gas/elf/common3a.d
@ -0,0 +1,7 @@
+#source: common3.s
+#as: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/gas/testsuite/gas/elf/common3b.d
+++ b/gas/testsuite/gas/elf/common3b.d
@ -0,0 +1,7 @@
+#source: common3.s
+#as: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/gas/testsuite/gas/elf/common4.s
+++ b/gas/testsuite/gas/elf/common4.s
@ -0,0 +1 @@
+	.tls_common foobar,30,4
--- a/gas/testsuite/gas/elf/common4a.d
+++ b/gas/testsuite/gas/elf/common4a.d
@ -0,0 +1,7 @@
+#source: common4.s
+#as: --elf-stt-common=yes
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/gas/testsuite/gas/elf/common4b.d
+++ b/gas/testsuite/gas/elf/common4b.d
@ -0,0 +1,7 @@
+#source: common4.s
+#as: --elf-stt-common=no
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/gas/testsuite/gas/elf/elf.exp
+++ b/gas/testsuite/gas/elf/elf.exp
@ -218,6 +218,10 @@ if { [is_elf_format] } then {
    if { ![istarget "*-*-hpux*"] } then {
 	run_dump_test "common1"
 	run_dump_test "common2"
+	run_dump_test "common3a"
+	run_dump_test "common3b"
+	run_dump_test "common4a"
+	run_dump_test "common4b"
    }

    run_dump_test "strtab"
--- a/gas/testsuite/gas/i386/dw2-compressed-3.d
+++ b/gas/testsuite/gas/i386/dw2-compressed-3.d
@ -1,7 +1,7 @@
 #source: dw2-compress-3.s
-#as: --compress-debug-sections=zlib-gabi
+#as: --compress-debug-sections --elf-stt-common=no
 #readelf: -w
-#name: DWARF2 debugging information 3 with SHF_COMPRESSED
+#name: DWARF2 debugging information 3 w/o STT_COMMON

 Contents of the .debug_info section:

--- a/gas/testsuite/gas/i386/dw2-compress-3b.d
+++ b/gas/testsuite/gas/i386/dw2-compress-3b.d
@ -1,6 +1,7 @@
-#as: --compress-debug-sections
+#source: dw2-compress-3.s
+#as: --compress-debug-sections --elf-stt-common=yes
 #readelf: -w
-#name: DWARF2 debugging information 3
+#name: DWARF2 debugging information 3 with STT_COMMON

 Contents of the .debug_info section:

--- a/gas/testsuite/gas/i386/dw2-compressed-3a.d
+++ b/gas/testsuite/gas/i386/dw2-compressed-3a.d
@ -0,0 +1,104 @@
+#source: dw2-compress-3.s
+#as: --compress-debug-sections=zlib-gabi --elf-stt-common=no
+#readelf: -w
+#name: DWARF2 debugging information 3 with SHF_COMPRESSED w/o STT_COMMON
+
+Contents of the .debug_info section:
+
+  Compilation Unit @ offset 0x0:
+   Length:        0x32 \(32-bit\)
+   Version:       4
+   Abbrev Offset: 0x0
+   Pointer Size:  4
+ <0><b>: Abbrev Number: 1 \(DW_TAG_compile_unit\)
+    <c>   DW_AT_producer    : \(indirect string, offset: 0x2\): GNU C 4.8.3
+    <10>   DW_AT_language    : 1	\(ANSI C\)
+    <11>   DW_AT_name        : \(indirect string, offset: 0xe\): dw2-compress-3.c
+    <15>   DW_AT_comp_dir    : \(indirect string, offset: 0x0\): .
+    <19>   DW_AT_stmt_list   : 0x0
+ <1><1d>: Abbrev Number: 2 \(DW_TAG_variable\)
+    <1e>   DW_AT_name        : foo
+    <22>   DW_AT_decl_file   : 1
+    <23>   DW_AT_decl_line   : 1
+    <24>   DW_AT_type        : <0x2e>
+    <28>   DW_AT_external    : 1
+    <28>   DW_AT_location    : 5 byte block: 3 4 0 0 0 	\(DW_OP_addr: 4\)
+ <1><2e>: Abbrev Number: 3 \(DW_TAG_base_type\)
+    <2f>   DW_AT_byte_size   : 4
+    <30>   DW_AT_encoding    : 5	\(signed\)
+    <31>   DW_AT_name        : int
+ <1><35>: Abbrev Number: 0
+
+Contents of the .debug_abbrev section:
+
+  Number TAG \(0x0\)
+   1      DW_TAG_compile_unit    \[has children\]
+    DW_AT_producer     DW_FORM_strp
+    DW_AT_language     DW_FORM_data1
+    DW_AT_name         DW_FORM_strp
+    DW_AT_comp_dir     DW_FORM_strp
+    DW_AT_stmt_list    DW_FORM_sec_offset
+    DW_AT value: 0     DW_FORM value: 0
+   2      DW_TAG_variable    \[no children\]
+    DW_AT_name         DW_FORM_string
+    DW_AT_decl_file    DW_FORM_data1
+    DW_AT_decl_line    DW_FORM_data1
+    DW_AT_type         DW_FORM_ref4
+    DW_AT_external     DW_FORM_flag_present
+    DW_AT_location     DW_FORM_exprloc
+    DW_AT value: 0     DW_FORM value: 0
+   3      DW_TAG_base_type    \[no children\]
+    DW_AT_byte_size    DW_FORM_data1
+    DW_AT_encoding     DW_FORM_data1
+    DW_AT_name         DW_FORM_string
+    DW_AT value: 0     DW_FORM value: 0
+
+Contents of the .debug_aranges section:
+
+  Length:                   20
+  Version:                  2
+  Offset into .debug_info:  0x0
+  Pointer Size:             4
+  Segment Size:             0
+
+    Address    Length
+    00000000 00000000 
+
+Raw dump of debug contents of section .debug_line:
+
+  Offset:                      0x0
+  Length:                      45
+  DWARF Version:               2
+  Prologue Length:             39
+  Minimum Instruction Length:  1
+  Initial value of 'is_stmt':  1
+  Line Base:                   -5
+  Line Range:                  14
+  Opcode Base:                 13
+
+ Opcodes:
+  Opcode 1 has 0 args
+  Opcode 2 has 1 args
+  Opcode 3 has 1 args
+  Opcode 4 has 1 args
+  Opcode 5 has 1 args
+  Opcode 6 has 0 args
+  Opcode 7 has 0 args
+  Opcode 8 has 0 args
+  Opcode 9 has 1 args
+  Opcode 10 has 0 args
+  Opcode 11 has 0 args
+  Opcode 12 has 1 args
+
+ The Directory Table is empty.
+
+ The File Name Table \(offset 0x1c\):
+  Entry	Dir	Time	Size	Name
+  1	0	0	0	dw2-compress-3.c
+
+ No Line Number Statements.
+Contents of the .debug_str section:
+
+  0x00000000 2e00474e 55204320 342e382e 33006477 ..GNU C 4.8.3.dw
+  0x00000010 322d636f 6d707265 73732d33 2e6300   2-compress-3.c.
+
--- a/gas/testsuite/gas/i386/dw2-compressed-3b.d
+++ b/gas/testsuite/gas/i386/dw2-compressed-3b.d
@ -0,0 +1,104 @@
+#source: dw2-compress-3.s
+#as: --compress-debug-sections=zlib-gabi --elf-stt-common=yes
+#readelf: -w
+#name: DWARF2 debugging information 3 with SHF_COMPRESSED with STT_COMMON
+
+Contents of the .debug_info section:
+
+  Compilation Unit @ offset 0x0:
+   Length:        0x32 \(32-bit\)
+   Version:       4
+   Abbrev Offset: 0x0
+   Pointer Size:  4
+ <0><b>: Abbrev Number: 1 \(DW_TAG_compile_unit\)
+    <c>   DW_AT_producer    : \(indirect string, offset: 0x2\): GNU C 4.8.3
+    <10>   DW_AT_language    : 1	\(ANSI C\)
+    <11>   DW_AT_name        : \(indirect string, offset: 0xe\): dw2-compress-3.c
+    <15>   DW_AT_comp_dir    : \(indirect string, offset: 0x0\): .
+    <19>   DW_AT_stmt_list   : 0x0
+ <1><1d>: Abbrev Number: 2 \(DW_TAG_variable\)
+    <1e>   DW_AT_name        : foo
+    <22>   DW_AT_decl_file   : 1
+    <23>   DW_AT_decl_line   : 1
+    <24>   DW_AT_type        : <0x2e>
+    <28>   DW_AT_external    : 1
+    <28>   DW_AT_location    : 5 byte block: 3 4 0 0 0 	\(DW_OP_addr: 4\)
+ <1><2e>: Abbrev Number: 3 \(DW_TAG_base_type\)
+    <2f>   DW_AT_byte_size   : 4
+    <30>   DW_AT_encoding    : 5	\(signed\)
+    <31>   DW_AT_name        : int
+ <1><35>: Abbrev Number: 0
+
+Contents of the .debug_abbrev section:
+
+  Number TAG \(0x0\)
+   1      DW_TAG_compile_unit    \[has children\]
+    DW_AT_producer     DW_FORM_strp
+    DW_AT_language     DW_FORM_data1
+    DW_AT_name         DW_FORM_strp
+    DW_AT_comp_dir     DW_FORM_strp
+    DW_AT_stmt_list    DW_FORM_sec_offset
+    DW_AT value: 0     DW_FORM value: 0
+   2      DW_TAG_variable    \[no children\]
+    DW_AT_name         DW_FORM_string
+    DW_AT_decl_file    DW_FORM_data1
+    DW_AT_decl_line    DW_FORM_data1
+    DW_AT_type         DW_FORM_ref4
+    DW_AT_external     DW_FORM_flag_present
+    DW_AT_location     DW_FORM_exprloc
+    DW_AT value: 0     DW_FORM value: 0
+   3      DW_TAG_base_type    \[no children\]
+    DW_AT_byte_size    DW_FORM_data1
+    DW_AT_encoding     DW_FORM_data1
+    DW_AT_name         DW_FORM_string
+    DW_AT value: 0     DW_FORM value: 0
+
+Contents of the .debug_aranges section:
+
+  Length:                   20
+  Version:                  2
+  Offset into .debug_info:  0x0
+  Pointer Size:             4
+  Segment Size:             0
+
+    Address    Length
+    00000000 00000000 
+
+Raw dump of debug contents of section .debug_line:
+
+  Offset:                      0x0
+  Length:                      45
+  DWARF Version:               2
+  Prologue Length:             39
+  Minimum Instruction Length:  1
+  Initial value of 'is_stmt':  1
+  Line Base:                   -5
+  Line Range:                  14
+  Opcode Base:                 13
+
+ Opcodes:
+  Opcode 1 has 0 args
+  Opcode 2 has 1 args
+  Opcode 3 has 1 args
+  Opcode 4 has 1 args
+  Opcode 5 has 1 args
+  Opcode 6 has 0 args
+  Opcode 7 has 0 args
+  Opcode 8 has 0 args
+  Opcode 9 has 1 args
+  Opcode 10 has 0 args
+  Opcode 11 has 0 args
+  Opcode 12 has 1 args
+
+ The Directory Table is empty.
+
+ The File Name Table \(offset 0x1c\):
+  Entry	Dir	Time	Size	Name
+  1	0	0	0	dw2-compress-3.c
+
+ No Line Number Statements.
+Contents of the .debug_str section:
+
+  0x00000000 2e00474e 55204320 342e382e 33006477 ..GNU C 4.8.3.dw
+  0x00000010 322d636f 6d707265 73732d33 2e6300   2-compress-3.c.
+
--- a/gas/testsuite/gas/i386/i386.exp
+++ b/gas/testsuite/gas/i386/i386.exp
@ -448,9 +448,11 @@ if [expr [istarget "i*86-*-*"] || [istarget "x86_64-*-*"]] then {
 	run_list_test_stdin "list-2" "-al"
 	run_list_test_stdin "list-3" "-al"
 	run_dump_test "dw2-compress-1"
-	run_dump_test "dw2-compress-3"
+	run_dump_test "dw2-compress-3a"
+	run_dump_test "dw2-compress-3b"
 	run_dump_test "dw2-compressed-1"
-	run_dump_test "dw2-compressed-3"
+	run_dump_test "dw2-compressed-3a"
+	run_dump_test "dw2-compressed-3b"
    }
 }

--- a/gas/write.c
+++ b/gas/write.c
@ -2209,6 +2209,11 @@ write_object_file (void)
  obj_frob_file_after_relocs ();
 #endif

+#if defined OBJ_ELF || defined OBJ_MAYBE_ELF
+  if (IS_ELF && flag_use_elf_stt_common)
+    stdoutput->flags |= BFD_CONVERT_ELF_COMMON | BFD_USE_ELF_STT_COMMON;
+#endif
+
  /* Once all relocations have been written, we can compress the
     contents of the debug sections.  This needs to be done before
     we start writing any sections, because it will affect the file
--- a/include/bfdlink.h
+++ b/include/bfdlink.h
@ -42,6 +42,15 @@ enum bfd_link_discard
  discard_all		/* Discard all locals.  */
 };

+/* Whether to generate ELF common symbols with the STT_COMMON type
+   during a relocatable link.  */
+enum bfd_link_elf_stt_common
+{
+  unchanged,
+  elf_stt_common,
+  no_elf_stt_common
+};
+
 /* Describes the type of hash table entry structure being used.
   Different hash table structure have different fields and so
   support different linking features.  */
@ -321,6 +330,9 @@ struct bfd_link_info
  /* Which local symbols to discard.  */
  ENUM_BITFIELD (bfd_link_discard) discard : 2;

+  /* Whether to generate ELF common symbols with the STT_COMMON type.  */
+  ENUM_BITFIELD (bfd_link_elf_stt_common) elf_stt_common : 2;
+
  /* Criteria for skipping symbols when determining
     whether to include an object from an archive. */
  ENUM_BITFIELD (bfd_link_common_skip_ar_symbols) common_skip_ar_symbols : 2;
--- a/ld/NEWS
+++ b/ld/NEWS
@ -1,5 +1,8 @@
 -*- text -*-

+* Add -z common/-z nocommon options for ELF targets to control whether to
+  convert common symbols to the STT_COMMON type during a relocatable link.
+
 * Support for -z nodynamic-undefined-weak in the x86 ELF linker, which
  avoids dynamic relocations against undefined weak symbols in executable.

--- a/ld/emultempl/elf32.em
+++ b/ld/emultempl/elf32.em
@ -2421,6 +2421,10 @@ fragment <<EOF
 	link_info.relro = TRUE;
      else if (strcmp (optarg, "norelro") == 0)
 	link_info.relro = FALSE;
+      else if (strcmp (optarg, "common") == 0)
+	link_info.elf_stt_common = elf_stt_common;
+      else if (strcmp (optarg, "nocommon") == 0)
+	link_info.elf_stt_common = no_elf_stt_common;
      else if (strcmp (optarg, "text") == 0)
 	link_info.error_textrel = TRUE;
      else if (strcmp (optarg, "notext") == 0)
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@ -1092,6 +1092,10 @@ The recognized keywords are:
 Combines multiple reloc sections and sorts them to make dynamic symbol
 lookup caching possible.

+@item common
+Generate common symbols with the STT_COMMON type druing a relocatable
+link.
+
@item defs
 Disallows undefined symbols in object files.  Undefined symbols in
 shared libraries are still allowed.
@ -1132,6 +1136,10 @@ Allows multiple definitions.
@item nocombreloc
 Disables multiple reloc sections combining.

+@item nocommon
+Generate common symbols with the STT_OBJECT type druing a relocatable
+link.
+
@item nocopyreloc
 Disable linker generated .dynbss variables used in place of variables
 defined in shared libraries.  May result in dynamic text relocations.
--- a/ld/lexsup.c
+++ b/ld/lexsup.c
@ -1759,6 +1759,10 @@ elf_shlib_list_options (FILE *file)
  fprintf (file, _("\
  -z norelro                  Don't create RELRO program header\n"));
  fprintf (file, _("\
+  -z common                   Generate common symbols with STT_COMMON type\n"));
+  fprintf (file, _("\
+  -z nocommon                 Generate common symbols with STT_OBJECT type\n"));
+  fprintf (file, _("\
  -z stacksize=SIZE           Set size of stack segment\n"));
  fprintf (file, _("\
  -z text                     Treat DT_TEXTREL in shared object as error\n"));
--- a/ld/testsuite/ld-elf/tls_common.exp
+++ b/ld/testsuite/ld-elf/tls_common.exp
@ -41,17 +41,19 @@ global srcdir
 global subdir
 global link_output

-if { ![ld_assemble $as $srcdir/$subdir/tls_common.s tmpdir/tls_common.o ] } {
+if { ![ld_assemble $as "--elf-stt-common=no $srcdir/$subdir/tls_common.s" tmpdir/tls_commona.o]
+      || ![ld_assemble $as "--elf-stt-common=yes $srcdir/$subdir/tls_common.s" tmpdir/tls_commonb.o] } {
    unresolved "tls_common"
    return
 }

-if { ![ld_simple_link $ld tmpdir/tls_common1.o "-r tmpdir/tls_common.o"] } {
+if { ![ld_simple_link $ld tmpdir/tls_common1a.o "-r tmpdir/tls_commona.o"]
+     || ![ld_simple_link $ld tmpdir/tls_common1b.o "-r tmpdir/tls_commona.o"] } {
    fail "tls_common"
    return
 }

-if { ![ld_simple_link $ld tmpdir/tls_common "tmpdir/tls_common1.o"] } {
+if { ![ld_simple_link $ld tmpdir/tls_commona "tmpdir/tls_common1a.o"] } {
    if { [string match "*not supported*" $link_output]
 	 || [string match "*unrecognized option*" $link_output] } {
 	unsupported "$ld_options is not supported by this target"
@ -63,7 +65,26 @@ if { ![ld_simple_link $ld tmpdir/tls_common "tmpdir/tls_common1.o"] } {
    return
 }

-set readelf_output [run_host_cmd "$READELF" "-l --wide tmpdir/tls_common"]
+if { ![ld_simple_link $ld tmpdir/tls_commonb "tmpdir/tls_common1b.o"] } {
+    if { [string match "*not supported*" $link_output]
+	 || [string match "*unrecognized option*" $link_output] } {
+	unsupported "$ld_options is not supported by this target"
+    } elseif { [string match "*Warning*alignment*of common symbol*" $link_output] } {
+	fail "tls_common"
+    } else {
+	unresolved "tls_common"
+    }
+    return
+}
+
+set readelf_output [run_host_cmd "$READELF" "-l --wide tmpdir/tls_commona"]
+if ![regexp ".*TLS.*0x0+ 0x0+4 R .*" $readelf_output] then {
+    send_log "$readelf_output\n"
+    fail "tls_common"
+    return
+}
+
+set readelf_output [run_host_cmd "$READELF" "-l --wide tmpdir/tls_commona"]
 if ![regexp ".*TLS.*0x0+ 0x0+4 R .*" $readelf_output] then {
    send_log "$readelf_output\n"
    fail "tls_common"
--- a/ld/testsuite/ld-elfcomm/common-1.s
+++ b/ld/testsuite/ld-elfcomm/common-1.s
@ -0,0 +1,3 @@
+	.data
+	.dc.a foobar
+	.comm foobar,30,4
--- a/ld/testsuite/ld-elfcomm/common-1a.d
+++ b/ld/testsuite/ld-elfcomm/common-1a.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-1b.d
+++ b/ld/testsuite/ld-elfcomm/common-1b.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-1c.d
+++ b/ld/testsuite/ld-elfcomm/common-1c.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-1d.d
+++ b/ld/testsuite/ld-elfcomm/common-1d.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-1e.d
+++ b/ld/testsuite/ld-elfcomm/common-1e.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-1f.d
+++ b/ld/testsuite/ld-elfcomm/common-1f.d
@ -0,0 +1,8 @@
+#source: common-1.s
+#as: --elf-stt-common=no
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2.s
+++ b/ld/testsuite/ld-elfcomm/common-2.s
@ -0,0 +1,3 @@
+	.data
+	.dc.a foobar
+	.tls_common foobar,30,4
--- a/ld/testsuite/ld-elfcomm/common-2a.d
+++ b/ld/testsuite/ld-elfcomm/common-2a.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2b.d
+++ b/ld/testsuite/ld-elfcomm/common-2b.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2c.d
+++ b/ld/testsuite/ld-elfcomm/common-2c.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2d.d
+++ b/ld/testsuite/ld-elfcomm/common-2d.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=yes
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2e.d
+++ b/ld/testsuite/ld-elfcomm/common-2e.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-2f.d
+++ b/ld/testsuite/ld-elfcomm/common-2f.d
@ -0,0 +1,8 @@
+#source: common-2.s
+#as: --elf-stt-common=no
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +TLS +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-3a.rd
+++ b/ld/testsuite/ld-elfcomm/common-3a.rd
@ -0,0 +1,6 @@
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/common-3b.rd
+++ b/ld/testsuite/ld-elfcomm/common-3b.rd
@ -0,0 +1,6 @@
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +COM +foobar
+#pass
--- a/ld/testsuite/ld-elfcomm/dummy.s
+++ b/ld/testsuite/ld-elfcomm/dummy.s
@ -0,0 +1 @@
+# Dummy
--- a/ld/testsuite/ld-elfcomm/elfcomm.exp
+++ b/ld/testsuite/ld-elfcomm/elfcomm.exp
@ -144,7 +144,7 @@ proc stt_common_test { options testname } {
    global READELF
    global ld

-    set options "$options tmpdir/common1a.o"
+    set options "$options tmpdir/common1c.o"

    if { ! [ld_simple_link $ld tmpdir/common.exe $options] } {
      unresolved $testname
@ -154,7 +154,7 @@ proc stt_common_test { options testname } {
    send_log "$READELF --syms tmpdir/common.exe | grep foo\n"
    set exec_output [run_host_cmd "$READELF" "--syms tmpdir/common.exe | grep foo"]

-    if {![regexp "(\[ 	\]*)(\[0-9\]+):(\[ 	\]*)(\[0-9\]+)(\[ 	\]+)(\[0-9\]+)(\[ 	\]+)COMMON(\[ 	\]+)GLOBAL(\[ 	\]+)DEFAULT(\[ 	\]+)(\[0-9\]+)(\[ 	\]+)_?foo2" $exec_output] } {
+    if {![regexp { +[0-9a-f]+. +[0-9a-f]+ OBJECT + GLOBAL +DEFAULT +[0-9]+ _?foo2} $exec_output] } {
 	fail $testname
 	return 0
    }
@ -163,23 +163,6 @@ proc stt_common_test { options testname } {
    return 1
 }

-# Check to see if the assembler is generating symbols with the STT_COMMON type.
-proc assembler_generates_commons {} {
-    global exec_output
-    global READELF
-
-    verbose "Check to see if STT_COMMON symbols are being generated:"
-    set exec_output [run_host_cmd "$READELF" "--syms tmpdir/common1a.o | grep foo"]
-
-    if { ![regexp "(\[ 	\]*)(\[0-9\]+):(\[ 	\]*)(\[0\]*)80(\[ 	\]+).(\[ 	\]+)COMMON(\[ 	\]+)GLOBAL(\[ 	\]+)DEFAULT(\[ 	\]+)(PRC\\\[0xff03\\\]|COM|SCOM)(\[ 	\]+)_?foo2" $exec_output] } {
-	verbose "STT_COMMON not generated"
-	return 0
-    }
-
-    verbose "STT_COMMON's are generated"
-    return 1
-}
-
 if [istarget nios2*-*-*] {
    set CFLAGS "$CFLAGS -G0"
 }
@ -187,7 +170,9 @@ if [istarget nios2*-*-*] {
 # Explicitly use "-fcommon" so that even if $CFLAGS includes
 # "-fno-common", these tests are compiled as expected.
 if {   ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1a.c tmpdir/common1a.o]
-    || ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1b.o] } {
+    || ![ld_compile "$CC $CFLAGS -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1b.o]
+    || ![ld_compile "$CC $CFLAGS -Wa,--elf-stt-common=yes -fcommon" $srcdir/$subdir/common1b.c tmpdir/common1c.o] } {
+    unresolved $test1
    unresolved $test1
    return
 }
@ -261,12 +246,56 @@ if { [dump_common1 $test1c2] } {
 #
 # The following tests are for when we are generating STT_COMMON symbols only.
 #
-
-if { ![assembler_generates_commons] } {
-    return
-}
-
 stt_common_test "-static -e 0" "static link of common symbols"
 stt_common_test "-shared"      "shared link of common symbols"
 stt_common_test "-pie"         "position independent link of common symbols"

+run_ld_link_tests [list \
+  [list \
+    "Build common-3x.o" \
+     "-r" "" "--elf-stt-common=no" \
+     {common-1.s} {} "common-3x.o" \
+  ] \
+  [list \
+    "Build common-3y.o" \
+     "-r" "" "--elf-stt-common=yes" \
+     {common-1.s} {} "common-3y.o" \
+  ] \
+  [list \
+    "Build common-3a.o" \
+    "-r tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3a.o" \
+  ] \
+  [list \
+    "Build common-3b.o" \
+    "-r tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3b.o" \
+  ] \
+  [list \
+    "Build common-3c.o" \
+    "-r -z nocommon tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3c.o" \
+  ] \
+  [list \
+    "Build common-3d.o" \
+    "-r -z common tmpdir/common-3x.o tmpdir/common-3y.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3b.o" \
+  ] \
+  [list \
+    "Build common-3e.o" \
+    "-r -z common tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3b.rd}} "common-3e.o" \
+  ] \
+  [list \
+    "Build common-3f.o" \
+    "-r -z nocommon tmpdir/common-3y.o tmpdir/common-3x.o" "" "" \
+    {dummy.s} {{readelf {-s -W} common-3a.rd}} "common-3f.o" \
+  ] \
+]
+
+set test_list [lsort [glob -nocomplain $srcdir/$subdir/*.d]]
+foreach t $test_list {
+    # We need to strip the ".d", but can leave the dirname.
+    verbose [file rootname $t]
+    run_dump_test [file rootname $t]
+}
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@ -349,6 +349,7 @@ run_dump_test "pr19636-4a"
 run_dump_test "pr19636-4b"
 run_dump_test "pr19636-4c"
 run_dump_test "pr19636-4d"
+run_dump_test "pr19645"

 if { !([istarget "i?86-*-linux*"]
       || [istarget "i?86-*-gnu*"]
--- a/ld/testsuite/ld-i386/pr19645.d
+++ b/ld/testsuite/ld-i386/pr19645.d
@ -0,0 +1,13 @@
+#as: --32 --elf-stt-common=yes
+#ld: -shared -Bsymbolic-functions -melf_i386
+#readelf: -r --wide --dyn-syms
+
+Relocation section '.rel.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
+ +Offset +Info +Type +Sym. Value +Symbol's Name
+[0-9a-f]+ +[0-9a-f]+ +R_386_GLOB_DAT +[0-9a-f]+ +foobar
+
+Symbol table '.dynsym' contains [0-9]+ entries:
+   Num:    Value  Size Type    Bind   Vis      Ndx Name
+#...
+ +[0-9]+: +[0-9a-f]+ +30 +OBJECT +GLOBAL +DEFAULT +[0-9]+ foobar
+#pass
--- a/ld/testsuite/ld-i386/pr19645.s
+++ b/ld/testsuite/ld-i386/pr19645.s
@ -0,0 +1,6 @@
+	.text
+	.global bar
+	.type bar,"function"
+bar:
+	movl foobar@GOT(%ebx), %eax
+	.comm foobar,30,4
--- a/ld/testsuite/ld-x86-64/dwarfreloc.exp
+++ b/ld/testsuite/ld-x86-64/dwarfreloc.exp
@ -41,18 +41,31 @@ if { !([istarget "x86_64-*-elf*"]
 }

 set build_tests_ld {
-  {"Build dwarfreloc1x.o"
-   "-r" "" ""
-   {dwarfreloc1.s} {} "dwarfreloc1x.o"}
-  {"Build dwarfreloc2.o"
-   "-r" "" ""
-   {dwarfreloc2.s} {} "dwarfreloc2x.o"}
+  {"Build dwarfreloc1xa.o"
+   "-r" "" "--elf-stt-common=no"
+   {dwarfreloc1.s} {} "dwarfreloc1xa.o"}
+  {"Build dwarfreloc1xb.o"
+   "-r" "" "--elf-stt-common=yes"
+   {dwarfreloc1.s} {} "dwarfreloc1xb.o"}
+  {"Build dwarfreloc2a.o"
+   "-r" "" "--elf-stt-common=no"
+   {dwarfreloc2.s} {} "dwarfreloc2xa.o"}
+  {"Build dwarfreloc2b.o"
+   "-r" "" "--elf-stt-common=yes"
+   {dwarfreloc2.s} {} "dwarfreloc2xb.o"}
 }

 run_ld_link_tests $build_tests_ld

-set testname "Link dwarfreloc1x.o and dwarfreloc2x.o to dwarfreloc.o"
-if [ld_simple_link $ld "tmpdir/dwarfreloc.o" "-r tmpdir/dwarfreloc1x.o tmpdir/dwarfreloc2x.o"] {
+set testname "Link dwarfreloc1xa.o and dwarfreloc2xa.o to dwarfreloca.o"
+if [ld_simple_link $ld "tmpdir/dwarfreloca.o" "-r tmpdir/dwarfreloc1xa.o tmpdir/dwarfreloc2xa.o"] {
+    pass $testname
+} else {
+    fail $testname
+}
+
+set testname "Link dwarfreloc1xb.o and dwarfreloc2xb.o to dwarfrelocb.o"
+if [ld_simple_link $ld "tmpdir/dwarfrelocb.o" "-r tmpdir/dwarfreloc1xb.o tmpdir/dwarfreloc2xb.o"] {
    pass $testname
 } else {
    fail $testname
@ -61,9 +74,34 @@ if [ld_simple_link $ld "tmpdir/dwarfreloc.o" "-r tmpdir/dwarfreloc1x.o tmpdir/dw
 # The code is copied from `ld-lib.exp'.  We cannot use the functions there as
 # they expect source (.s or .c) files while we to check a `ld -r' output (.o).

-set testname "Check dwarfreloc.o readelf"
+set testname "Check dwarfreloca.o readelf"
 set dumpfile "dwarfreloc.rd"
-set cmd "$READELF --debug-dump=info tmpdir/dwarfreloc.o"
+set cmd "$READELF --debug-dump=info tmpdir/dwarfreloca.o"
+set status [remote_exec host [concat sh -c [list "$cmd >dump.out 2>ld.stderr"]] "" "/dev/null"]
+send_log "$cmd\n"
+remote_upload host "ld.stderr"
+set comp_output [prune_warnings [file_contents "ld.stderr"]]
+remote_file host delete "ld.stderr"
+remote_file build delete "ld.stderr"
+
+if ![string match "" $comp_output] then {
+    send_log "$comp_output\n"
+    fail $testname
+} else {
+    remote_upload host "dump.out"
+    if { [regexp_diff "dump.out" "$srcdir/$subdir/$dumpfile"] } then {
+	verbose "output is [file_contents "dump.out"]" 2
+	fail $testname
+    } else {
+	pass $testname
+    }
+    remote_file build delete "dump.out"
+    remote_file host delete "dump.out"
+}
+
+set testname "Check dwarfrelocb.o readelf"
+set dumpfile "dwarfreloc.rd"
+set cmd "$READELF --debug-dump=info tmpdir/dwarfrelocb.o"
 set status [remote_exec host [concat sh -c [list "$cmd >dump.out 2>ld.stderr"]] "" "/dev/null"]
 send_log "$cmd\n"
 remote_upload host "ld.stderr"
--- a/ld/testsuite/ld-x86-64/largecomm-1.s
+++ b/ld/testsuite/ld-x86-64/largecomm-1.s
@ -0,0 +1,3 @@
+	.data
+	.dc.a foobar
+	.largecomm foobar,30,4
--- a/ld/testsuite/ld-x86-64/largecomm-1a.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1a.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=yes
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/largecomm-1b.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1b.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=no
+#ld: -r
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/largecomm-1c.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1c.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/largecomm-1d.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1d.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=yes
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/largecomm-1e.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1e.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=no
+#ld: -r -z common
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +COMMON +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/largecomm-1f.d
+++ b/ld/testsuite/ld-x86-64/largecomm-1f.d
@ -0,0 +1,8 @@
+#source: largecomm-1.s
+#as: --elf-stt-common=no
+#ld: -r -z nocommon
+#readelf: -s -W
+
+#...
+ +[0-9]+: +0+4 +30 +OBJECT +GLOBAL +DEFAULT +LARGE_COM +foobar
+#pass
--- a/ld/testsuite/ld-x86-64/pr19645.d
+++ b/ld/testsuite/ld-x86-64/pr19645.d
@ -0,0 +1,13 @@
+#as: --64 --elf-stt-common=yes
+#ld: -shared -Bsymbolic-functions -melf_x86_64
+#readelf: -r --wide --dyn-syms
+
+Relocation section '.rela.dyn' at offset 0x[0-9a-f]+ contains 1 entries:
+ +Offset +Info +Type +Symbol's Value +Symbol's Name \+ Addend
+[0-9a-f]+ +[0-9a-f]+ +R_X86_64_GLOB_DAT +[0-9a-f]+ +foobar \+ 0
+
+Symbol table '.dynsym' contains [0-9]+ entries:
+ +Num: +Value +Size +Type +Bind +Vis +Ndx +Name
+#...
+ +[0-9]+: +[0-9a-f]+ +30 +OBJECT +GLOBAL +DEFAULT +[0-9]+ foobar
+#pass
--- a/ld/testsuite/ld-x86-64/pr19645.s
+++ b/ld/testsuite/ld-x86-64/pr19645.s
@ -0,0 +1,6 @@
+	.text
+	.global bar
+	.type bar,"function"
+bar:
+	movq foobar@GOTPCREL(%rip), %rax
+	.comm foobar,30,4
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@ -239,6 +239,12 @@ run_dump_test "pr14215"
 run_dump_test "pr14207"
 run_dump_test "gotplt1"
 run_dump_test "pie1"
+run_dump_test "largecomm-1a"
+run_dump_test "largecomm-1b"
+run_dump_test "largecomm-1c"
+run_dump_test "largecomm-1d"
+run_dump_test "largecomm-1e"
+run_dump_test "largecomm-1f"

 if { ![istarget "x86_64-*-linux*"] && ![istarget "x86_64-*-nacl*"]} {
    return
@ -375,6 +381,7 @@ run_dump_test "pr19636-2i"
 run_dump_test "pr19636-3a"
 run_dump_test "pr19636-3b"
 run_dump_test "pr19636-3c"
+run_dump_test "pr19645"

 proc undefined_weak {cflags ldflags} {
    set testname "Undefined weak symbol"