fix Xtensa linker relaxation for weak symbols

[Bob Wilson <bwilson at tensilica dot com>]

Building a recent version of glibc (well, more recent than what I had previously 
been using...) has exposed a problem with the Xtensa port of the linker.  The 
linker relaxation, enabled by default for Xtensa, was incorrectly replacing weak 
aliases during partial links.  This patch fixes it so that comparisons of 
relocations require matching the same symbol hash entry except during final, 
static links where a less strict comparison of values is OK.

Tested by running the ld testsuite and building glibc.  Committed on the 
mainline and branch.

2004-04-21  Bob Wilson  <bob.wilson@acm.org>

	* elf32-xtensa.c (is_same_value): Add final_static_link argument and
	require relocations against a weak symbol to reference the same
	symbol hash entry if not a final, static link.
	(get_cached_value, add_value_map): Add final_static_link argument.
	(remove_literals): Pass final_static_link argument as needed.

Index: elf32-xtensa.c
===================================================================
RCS file: /cvs/src/src/bfd/elf32-xtensa.c,v
retrieving revision 1.24
diff -u -p -r1.24 elf32-xtensa.c
--- elf32-xtensa.c	27 Mar 2004 10:58:07 -0000	1.24
+++ elf32-xtensa.c	21 Apr 2004 17:52:37 -0000
@@ -3431,7 +3431,7 @@ struct value_map_hash_table_struct
 
 
 static bfd_boolean is_same_value
-  PARAMS ((const literal_value *, const literal_value *));
+  PARAMS ((const literal_value *, const literal_value *, bfd_boolean));
 static value_map_hash_table *value_map_hash_table_init
   PARAMS ((void));
 static unsigned hash_literal_value
@@ -3439,16 +3439,20 @@ static unsigned hash_literal_value
 static unsigned hash_bfd_vma
   PARAMS ((bfd_vma));
 static value_map *get_cached_value
-  PARAMS ((value_map_hash_table *, const literal_value *));
+  PARAMS ((value_map_hash_table *, const literal_value *, bfd_boolean));
 static value_map *add_value_map
-  PARAMS ((value_map_hash_table *, const literal_value *, const r_reloc *));
+  PARAMS ((value_map_hash_table *, const literal_value *, const r_reloc *,
+	   bfd_boolean));
 
 
 static bfd_boolean
-is_same_value (src1, src2)
+is_same_value (src1, src2, final_static_link)
      const literal_value *src1;
      const literal_value *src2;
+     bfd_boolean final_static_link;
 {
+  struct elf_link_hash_entry *h1, *h2;
+
   if (r_reloc_is_const (&src1->r_rel) != r_reloc_is_const (&src2->r_rel)) 
     return FALSE;
 
@@ -3466,8 +3470,14 @@ is_same_value (src1, src2)
   if (src1->value != src2->value)
     return FALSE;
   
-  /* Now check for the same section and the same elf_hash.  */
-  if (r_reloc_is_defined (&src1->r_rel))
+  /* Now check for the same section (if defined) or the same elf_hash
+     (if undefined or weak).  */
+  h1 = r_reloc_get_hash_entry (&src1->r_rel);
+  h2 = r_reloc_get_hash_entry (&src2->r_rel);
+  if (r_reloc_is_defined (&src1->r_rel)
+      && (final_static_link
+	  || ((!h1 || h1->root.type != bfd_link_hash_defweak)
+	      && (!h2 || h2->root.type != bfd_link_hash_defweak))))
     {
       if (r_reloc_get_section (&src1->r_rel)
 	  != r_reloc_get_section (&src2->r_rel))
@@ -3475,11 +3485,8 @@ is_same_value (src1, src2)
     }
   else
     {
-      if (r_reloc_get_hash_entry (&src1->r_rel)
-	  != r_reloc_get_hash_entry (&src2->r_rel))
-	return FALSE;
-
-      if (r_reloc_get_hash_entry (&src1->r_rel) == 0)
+      /* Require that the hash entries (i.e., symbols) be identical.  */
+      if (h1 != h2 || h1 == 0)
 	return FALSE;
     }
 
@@ -3540,9 +3547,10 @@ hash_literal_value (src)
 /* Check if the specified literal_value has been seen before.  */
 
 static value_map *
-get_cached_value (map, val)
+get_cached_value (map, val, final_static_link)
      value_map_hash_table *map;
      const literal_value *val;
+     bfd_boolean final_static_link;
 {
   value_map *map_e;
   value_map *bucket;
@@ -3553,7 +3561,7 @@ get_cached_value (map, val)
   bucket = map->buckets[idx];
   for (map_e = bucket; map_e; map_e = map_e->next)
     {
-      if (is_same_value (&map_e->val, val))
+      if (is_same_value (&map_e->val, val, final_static_link))
 	return map_e;
     }
   return NULL;
@@ -3564,17 +3572,18 @@ get_cached_value (map, val)
    already has an entry here.  */
 
 static value_map *
-add_value_map (map, val, loc)
+add_value_map (map, val, loc, final_static_link)
      value_map_hash_table *map;
      const literal_value *val;
      const r_reloc *loc;
+     bfd_boolean final_static_link;
 {
   value_map **bucket_p;
   unsigned idx;
 
   value_map *val_e = (value_map *) bfd_zmalloc (sizeof (value_map));
 
-  BFD_ASSERT (get_cached_value (map, val) == NULL);
+  BFD_ASSERT (get_cached_value (map, val, final_static_link) == NULL);
   val_e->val = *val;
   val_e->loc = *loc;
 
@@ -4480,6 +4489,7 @@ remove_literals (abfd, sec, link_info, v
   bfd_byte *contents;
   Elf_Internal_Rela *internal_relocs;
   source_reloc *src_relocs;
+  bfd_boolean final_static_link;
   bfd_boolean ok = TRUE;
   int i;
 
@@ -4500,6 +4510,10 @@ remove_literals (abfd, sec, link_info, v
       goto error_return;
     }
 
+  final_static_link =
+    (!link_info->relocatable
+     && !elf_hash_table (link_info)->dynamic_sections_created);
+
   /* Sort the source_relocs by target offset.  */
   src_relocs = relax_info->src_relocs;
   qsort (src_relocs, relax_info->src_count,
@@ -4552,7 +4566,7 @@ remove_literals (abfd, sec, link_info, v
       val.value = bfd_get_32 (abfd, contents + rel->r_rel.target_offset);
           
       /* Check if we've seen another literal with the same value.  */
-      val_map = get_cached_value (values, &val);
+      val_map = get_cached_value (values, &val, final_static_link);
       if (val_map != NULL) 
 	{
 	  /* First check that THIS and all the other relocs to this
@@ -4575,7 +4589,7 @@ remove_literals (abfd, sec, link_info, v
 	{
 	  /* This is the first time we've seen this literal value.  */
 	  BFD_ASSERT (sec == r_reloc_get_section (&rel->r_rel));
-	  add_value_map (values, &val, &rel->r_rel);
+	  add_value_map (values, &val, &rel->r_rel, final_static_link);
 	}
     }