Index: gcc/c-decl.c
===================================================================
RCS file: /cvsroot/gcc/gcc/gcc/c-decl.c,v
retrieving revision 1.300.2.5
diff -u -p -r1.300.2.5 c-decl.c
--- gcc/c-decl.c	28 Mar 2002 18:49:57 -0000	1.300.2.5
+++ gcc/c-decl.c	23 Apr 2002 21:41:28 -0000
@@ -1955,7 +1955,11 @@ duplicate_decls (newdecl, olddecl, diffe
     }
 
   /* Merge the storage class information.  */
-  DECL_WEAK (newdecl) |= DECL_WEAK (olddecl);
+  if (DECL_WEAK (newdecl) && !DECL_WEAK (olddecl))
+    declare_weak (olddecl);
+  if (!DECL_WEAK (newdecl) && DECL_WEAK (olddecl))
+    declare_weak (newdecl);
+
   /* For functions, static overrides non-static.  */
   if (TREE_CODE (newdecl) == FUNCTION_DECL)
     {
Index: gcc/varasm.c
===================================================================
RCS file: /cvsroot/gcc/gcc/gcc/varasm.c,v
retrieving revision 1.250.2.7
diff -u -p -r1.250.2.7 varasm.c
--- gcc/varasm.c	25 Mar 2002 00:54:26 -0000	1.250.2.7
+++ gcc/varasm.c	23 Apr 2002 21:41:28 -0000
@@ -4998,17 +4998,25 @@ declare_weak (decl)
 {
   if (! TREE_PUBLIC (decl))
     error_with_decl (decl, "weak declaration of `%s' must be public");
-  else if (TREE_ASM_WRITTEN (decl))
+  else if (TREE_CODE (decl) == FUNCTION_DECL && TREE_ASM_WRITTEN (decl))
     error_with_decl (decl, "weak declaration of `%s' must precede definition");
   else if (SUPPORTS_WEAK)
     {
       if (! DECL_WEAK (decl))
 	weak_decls = tree_cons (NULL, decl, weak_decls);
+      if (TREE_CODE (decl) != FUNCTION_DECL && TREE_USED (decl))
+	warning_with_decl (decl, "weak declaration of `%s' after first use may result in unspecified behaviour");
     }
   else
     warning_with_decl (decl, "weak declaration of `%s' not supported");
 
   DECL_WEAK (decl) = 1;
+
+  if (DECL_RTL_SET_P (decl)
+      && GET_CODE (DECL_RTL (decl)) == MEM
+      && XEXP (DECL_RTL (decl), 0)
+      && GET_CODE (XEXP (DECL_RTL (decl), 0)) == SYMBOL_REF)
+    SYMBOL_REF_WEAK (XEXP (DECL_RTL (decl), 0)) = 1;
 }
 
 /* Emit any pending weak declarations.  */
Index: gcc/cp/decl.c
===================================================================
RCS file: /cvsroot/gcc/gcc/gcc/cp/decl.c,v
retrieving revision 1.866.2.23
diff -u -p -r1.866.2.23 decl.c
--- gcc/cp/decl.c	16 Apr 2002 03:15:54 -0000	1.866.2.23
+++ gcc/cp/decl.c	23 Apr 2002 21:41:28 -0000
@@ -3645,7 +3645,11 @@ duplicate_decls (newdecl, olddecl)
     }
 
   /* Merge the storage class information.  */
-  DECL_WEAK (newdecl) |= DECL_WEAK (olddecl);
+  if (DECL_WEAK (newdecl) && !DECL_WEAK (olddecl))
+    declare_weak (olddecl);
+  if (!DECL_WEAK (newdecl) && DECL_WEAK (olddecl))
+    declare_weak (newdecl);
+
   DECL_ONE_ONLY (newdecl) |= DECL_ONE_ONLY (olddecl);
   DECL_DEFER_OUTPUT (newdecl) |= DECL_DEFER_OUTPUT (olddecl);
   TREE_PUBLIC (newdecl) = TREE_PUBLIC (olddecl);