Properly handle common symbol and weak function

bfd/

	PR ld/14591
	* elf-bfd.h (_bfd_elf_merge_symbol): Add an argument to return
	if the old symbol is weak.

	* elf32-sh-symbian.c (sh_symbian_relocate_section): Update
	_bfd_elf_merge_symbol call.

	* elflink.c (_bfd_elf_merge_symbol): Add an argument to return
	if the old symbol is weak.
	(_bfd_elf_add_default_symbol): Update _bfd_elf_merge_symbol
	call.
	(elf_link_add_object_symbols): Don't update symbol type from a
	weak definition.  Update symbol type from a common symbol when
	overriding a weak symbol.

ld/testsuite/

	PR ld/14591
	* ld-elf/comm-data.exp (run_ld_link_tests): Add comm-data3a and
	comm-data3b tests.

	* ld-ifunc/ifunc.exp (run_ld_link_exec_tests): New.

	* ld-elf/comm-data3.sd: New file.
	* ld-elf/comm-data3a.s: Likewise.
	* ld-elf/comm-data3b.s: Likewise.
	* ld-ifunc/ifunc-17a-i386.d: Likewise.
	* ld-ifunc/ifunc-17a-x86-64.d: Likewise.
	* ld-ifunc/ifunc-17a.s: Likewise.
	* ld-ifunc/ifunc-17b-i386.d: Likewise.
	* ld-ifunc/ifunc-17b-x86-64.d: Likewise.
	* ld-ifunc/ifunc-17b.s: Likewise.
	* ld-ifunc/ifunc-common-1.out: Likewise.
	* ld-ifunc/ifunc-common-1a.c: Likewise.
	* ld-ifunc/ifunc-common-1b.c: Likewise.

4 files changed, 33 insertions, 7 deletions

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 7a4334f51ed..f38d4ccb4be 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,20 @@
+2012-09-18  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/14591
+	* elf-bfd.h (_bfd_elf_merge_symbol): Add an argument to return 
+	if the old symbol is weak.
+
+	* elf32-sh-symbian.c (sh_symbian_relocate_section): Update
+	_bfd_elf_merge_symbol call.
+
+	* elflink.c (_bfd_elf_merge_symbol): Add an argument to return
+	if the old symbol is weak.
+	(_bfd_elf_add_default_symbol): Update _bfd_elf_merge_symbol
+	call.
+	(elf_link_add_object_symbols): Don't update symbol type from a
+	weak definition.  Update symbol type from a common symbol when
+	overriding a weak symbol.
+
 2012-09-17  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* elf32-i386.c (elf_i386_convert_mov_to_lea): Ignore discarded
diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 12250365a4b..3709af9f9c9 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -1970,7 +1970,7 @@ extern bfd_boolean _bfd_elf_maybe_strip_eh_frame_hdr
 
 extern bfd_boolean _bfd_elf_merge_symbol
   (bfd *, struct bfd_link_info *, const char *, Elf_Internal_Sym *,
-   asection **, bfd_vma *, unsigned int *,
+   asection **, bfd_vma *, bfd_boolean *, unsigned int *,
    struct elf_link_hash_entry **, bfd_boolean *,
    bfd_boolean *, bfd_boolean *, bfd_boolean *);
 
diff --git a/bfd/elf32-sh-symbian.c b/bfd/elf32-sh-symbian.c
index 0882d52b9a4..1f03dbc40e5 100644
--- a/bfd/elf32-sh-symbian.c
+++ b/bfd/elf32-sh-symbian.c
@@ -497,7 +497,7 @@ sh_symbian_relocate_section (bfd *                  output_bfd,
 	      if (! _bfd_elf_merge_symbol (input_bfd, info,
 					   ptr->new_name, & new_sym,
 					   & psec, & new_value, NULL,
-					   & new_hash, & skip,
+					   NULL, & new_hash, & skip,
 					   & override, & type_change_ok,
 					   & size_change_ok))
 		{
diff --git a/bfd/elflink.c b/bfd/elflink.c
index 9446e7d2ead..232c0b13c5a 100644
--- a/bfd/elflink.c
+++ b/bfd/elflink.c
@@ -941,6 +941,7 @@ _bfd_elf_merge_symbol (bfd *abfd,
 		       Elf_Internal_Sym *sym,
 		       asection **psec,
 		       bfd_vma *pvalue,
+		       bfd_boolean *pold_weak,
 		       unsigned int *pold_alignment,
 		       struct elf_link_hash_entry **sym_hash,
 		       bfd_boolean *skip,
@@ -1043,6 +1044,8 @@ _bfd_elf_merge_symbol (bfd *abfd,
   newweak = bind == STB_WEAK;
   oldweak = (h->root.type == bfd_link_hash_defweak
 	     || h->root.type == bfd_link_hash_undefweak);
+  if (pold_weak)
+    *pold_weak = oldweak;
 
   /* In cases involving weak versioned symbols, we may wind up trying
      to merge a symbol with itself.  Catch that here, to avoid the
@@ -1665,7 +1668,7 @@ _bfd_elf_add_default_symbol (bfd *abfd,
   size_change_ok = FALSE;
   sec = *psec;
   if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value,
-			      NULL, &hi, &skip, &override,
+			      NULL, NULL, &hi, &skip, &override,
 			      &type_change_ok, &size_change_ok))
     return FALSE;
 
@@ -1774,7 +1777,7 @@ nondefault:
   size_change_ok = FALSE;
   sec = *psec;
   if (!_bfd_elf_merge_symbol (abfd, info, shortname, sym, &sec, value,
-			      NULL, &hi, &skip, &override,
+			      NULL, NULL, &hi, &skip, &override,
 			      &type_change_ok, &size_change_ok))
     return FALSE;
 
@@ -3868,6 +3871,8 @@ error_free_dyn:
       bfd_boolean size_change_ok;
       bfd_boolean type_change_ok;
       bfd_boolean new_weakdef;
+      bfd_boolean new_weak;
+      bfd_boolean old_weak;
       bfd_boolean override;
       bfd_boolean common;
       unsigned int old_alignment;
@@ -4000,6 +4005,7 @@ error_free_dyn:
 
       size_change_ok = FALSE;
       type_change_ok = bed->type_change_ok;
+      old_weak = FALSE;
       old_alignment = 0;
       old_bfd = NULL;
       new_sec = sec;
@@ -4145,7 +4151,7 @@ error_free_dyn:
 	    }
 
 	  if (!_bfd_elf_merge_symbol (abfd, info, name, isym, &sec,
-				      &value, &old_alignment,
+				      &value, &old_weak, &old_alignment,
 				      sym_hash, &skip, &override,
 				      &type_change_ok, &size_change_ok))
 	    goto error_free_vers;
@@ -4207,10 +4213,11 @@ error_free_dyn:
       if (is_elf_hash_table (htab))
 	h->unique_global = (flags & BSF_GNU_UNIQUE) != 0;
 
+      new_weak = (flags & BSF_WEAK) != 0;
       new_weakdef = FALSE;
       if (dynamic
 	  && definition
-	  && (flags & BSF_WEAK) != 0
+	  && new_weak
 	  && !bed->is_function_type (ELF_ST_TYPE (isym->st_info))
 	  && is_elf_hash_table (htab)
 	  && h->u.weakdef == NULL)
@@ -4339,7 +4346,9 @@ error_free_dyn:
 	    h->size = h->root.u.c.size;
 
 	  if (ELF_ST_TYPE (isym->st_info) != STT_NOTYPE
-	      && (definition || h->type == STT_NOTYPE))
+	      && ((definition && !new_weak)
+		  || (old_weak && h->root.type == bfd_link_hash_common)
+		  || h->type == STT_NOTYPE))
 	    {
 	      unsigned int type = ELF_ST_TYPE (isym->st_info);