PATCH: ld/2300: ld does not report duplicate symbols defined in script file

["H. J. Lu" <hjl at lucon dot org>]

We don't check if a symbol is already defined when we make assignment.
This patch handle that. I can't use multiple_definition to check if
a multiple definition is real or not since it always returns TRUE.

I am not sure about the bfd_link_hash_defweak check. Can an
assignment override a weak definition?


H.J.
----
2006-02-08  H.J. Lu  <hongjiu.lu@intel.com>

	PR ld/2300:
	* ldexp.c (exp_fold_tree_1): Check if a symbol has been defined
	in input objects.

	* ldmain.c (multiple_definition): Renamed to ...
	(check_multiple_definition): This. Return FALSE if there is no
	multiple definition.
	(multiple_definition): Call check_multiple_definition and
	return TRUE.

	* ldmain.h (check_multiple_definition): New.

--- ld/ldexp.c.dup	2005-12-08 07:06:38.000000000 -0800
+++ ld/ldexp.c	2006-02-08 15:56:44.000000000 -0800
@@ -749,8 +749,28 @@ exp_fold_tree_1 (etree_type *tree)
 			   tree->assign.dst);
 		}
 
-	      /* FIXME: Should we worry if the symbol is already
-		 defined?  */
+	      if (!link_info.allow_multiple_definition)
+		{
+		  /* Check if the symbol is already defined.  */
+		  while (h->type == bfd_link_hash_indirect
+			 || h->type == bfd_link_hash_warning)
+		    h = h->u.i.link;
+
+		  if ((h->type == bfd_link_hash_defined
+		       || h->type == bfd_link_hash_defweak)
+		      && h->u.def.section->owner != output_bfd
+		      && h->u.def.section->owner != NULL
+		      && (h->u.def.section->owner->flags & DYNAMIC) == 0
+		      && check_multiple_definition (tree->assign.dst,
+						    h->u.def.section->owner, 
+						    h->u.def.section,
+						    h->u.def.value,
+						    output_bfd,
+						    expld.result.section,
+						    expld.result.value))
+		      einfo (_("%F%S: assignment to defined symbol\n"));
+		}
+
 	      lang_update_definedness (tree->assign.dst, h);
 	      h->type = bfd_link_hash_defined;
 	      h->u.def.value = expld.result.value;
--- ld/ldmain.c.dup	2005-11-11 10:48:53.000000000 -0800
+++ ld/ldmain.c	2006-02-08 15:49:18.000000000 -0800
@@ -982,18 +982,16 @@ add_archive_element (struct bfd_link_inf
   return TRUE;
 }
 
-/* This is called when BFD has discovered a symbol which is defined
-   multiple times.  */
+/* Return TRUE if a symbol is defined multiple times.  */
 
-static bfd_boolean
-multiple_definition (struct bfd_link_info *info ATTRIBUTE_UNUSED,
-		     const char *name,
-		     bfd *obfd,
-		     asection *osec,
-		     bfd_vma oval,
-		     bfd *nbfd,
-		     asection *nsec,
-		     bfd_vma nval)
+bfd_boolean
+check_multiple_definition (const char *name,
+			   bfd *obfd,
+			   asection *osec,
+			   bfd_vma oval,
+			   bfd *nbfd,
+			   asection *nsec,
+			   bfd_vma nval)
 {
   /* If either section has the output_section field set to
      bfd_abs_section_ptr, it means that the section is being
@@ -1006,7 +1004,7 @@ multiple_definition (struct bfd_link_inf
       || (nsec->output_section != NULL
 	  && ! bfd_is_abs_section (nsec)
 	  && bfd_is_abs_section (nsec->output_section)))
-    return TRUE;
+    return FALSE;
 
   einfo (_("%X%C: multiple definition of `%T'\n"),
 	 nbfd, nsec, nval, name);
@@ -1022,6 +1020,25 @@ multiple_definition (struct bfd_link_inf
   return TRUE;
 }
 
+/* This is called when BFD has discovered a symbol which is defined
+   multiple times.  */
+
+static bfd_boolean
+multiple_definition (struct bfd_link_info *info ATTRIBUTE_UNUSED,
+		     const char *name,
+		     bfd *obfd,
+		     asection *osec,
+		     bfd_vma oval,
+		     bfd *nbfd,
+		     asection *nsec,
+		     bfd_vma nval)
+{
+  /* FIXME: The return value from check_multiple_definition is
+     ignored.  */
+  check_multiple_definition (name, obfd, osec, oval, nbfd, nsec, nval);
+  return TRUE;
+}
+
 /* This is called when there is a definition of a common symbol, or
    when a common symbol is found for a symbol that is already defined,
    or when two common symbols are found.  We only do something if
--- ld/ldmain.h.dup	2005-05-16 11:04:40.000000000 -0700
+++ ld/ldmain.h	2006-02-08 15:48:06.000000000 -0800
@@ -43,5 +43,8 @@ extern int overflow_cutoff_limit;
 extern void add_ysym (const char *);
 extern void add_wrap (const char *);
 extern void add_keepsyms_file (const char *);
+extern bfd_boolean check_multiple_definition (const char *,
+					      bfd *, asection *, bfd_vma,
+					      bfd *, asection *, bfd_vma);
 
 #endif