cgraph.c (dump_cgraph_node): Dump alias flag.

	* cgraph.c (dump_cgraph_node): Dump alias flag.
	* cgraphunit.c (handle_alias_pairs): Handle weakrefs with no destination.
	(get_alias_symbol): New function.
	(output_weakrefs): Output also weakrefs with no destinatoin.
	(lto_output_node): Output weakref alias flag when at function boundary.

From-SVN: r180292

gcc/ChangeLog

+2011-10-21  Jan Hubicka  <jh@suse.cz>
+
+	* cgraph.c (dump_cgraph_node): Dump alias flag.
+	* cgraphunit.c (handle_alias_pairs): Handle weakrefs with no destination.
+	(get_alias_symbol): New function.
+	(output_weakrefs): Output also weakrefs with no destinatoin.
+	(lto_output_node): Output weakref alias flag when at function boundary.
+
 2011-10-21  Andrew Stubbs  <ams@codesourcery.com>
 
 	PR target/50809

gcc/cgraph.c

@@ -1838,6 +1838,8 @@ dump_cgraph_node (FILE *f, struct cgraph_node *node)
     fprintf (f, " only_called_at_startup");
   if (node->only_called_at_exit)
     fprintf (f, " only_called_at_exit");
+  else if (node->alias)
+    fprintf (f, " alias");
 
   fprintf (f, "\n");
 
@@ -2567,7 +2569,7 @@ cgraph_for_node_thunks_and_aliases (struct cgraph_node *node,
   for (e = node->callers; e; e = e->next_caller)
     if (e->caller->thunk.thunk_p
 	&& (include_overwritable
-	    || cgraph_function_body_availability (e->caller)))
+	    || cgraph_function_body_availability (e->caller) > AVAIL_OVERWRITABLE))
       if (cgraph_for_node_thunks_and_aliases (e->caller, callback, data,
 					      include_overwritable))
 	return true;

gcc/cgraphunit.c

@@ -1249,6 +1249,21 @@ handle_alias_pairs (void)
 	  varpool_create_variable_alias (p->decl, target_vnode->decl);
 	  VEC_unordered_remove (alias_pair, alias_pairs, i);
 	}
+      /* Weakrefs with target not defined in current unit are easy to handle; they
+	 behave just as external variables except we need to note the alias flag
+	 to later output the weakref pseudo op into asm file.  */
+      else if (lookup_attribute ("weakref", DECL_ATTRIBUTES (p->decl)) != NULL
+	       && (TREE_CODE (p->decl) == FUNCTION_DECL
+		   ? (varpool_node_for_asm (p->target) == NULL)
+		   : (cgraph_node_for_asm (p->target) == NULL)))
+	{
+	  if (TREE_CODE (p->decl) == FUNCTION_DECL)
+	    cgraph_get_create_node (p->decl)->alias = true;
+	  else
+	    varpool_get_node (p->decl)->alias = true;
+	  DECL_EXTERNAL (p->decl) = 1;
+	  VEC_unordered_remove (alias_pair, alias_pairs, i);
+	}
       else
 	{
 	  if (dump_file)
@@ -2064,6 +2079,18 @@ ipa_passes (void)
   bitmap_obstack_release (NULL);
 }
 
+
+/* Return string alias is alias of.  */
+
+static tree
+get_alias_symbol (tree decl)
+{
+  tree alias = lookup_attribute ("alias", DECL_ATTRIBUTES (decl));
+  return get_identifier (TREE_STRING_POINTER
+			  (TREE_VALUE (TREE_VALUE (alias))));
+}
+
+
 /* Weakrefs may be associated to external decls and thus not output
    at expansion time.  Emit all neccesary aliases.  */
 
@@ -2073,15 +2100,17 @@ output_weakrefs (void)
   struct cgraph_node *node;
   struct varpool_node *vnode;
   for (node = cgraph_nodes; node; node = node->next)
-    if (node->alias && node->thunk.alias && DECL_EXTERNAL (node->decl)
+    if (node->alias && DECL_EXTERNAL (node->decl)
         && !TREE_ASM_WRITTEN (node->decl))
       assemble_alias (node->decl,
-		      DECL_ASSEMBLER_NAME (node->thunk.alias));
+		      node->thunk.alias ? DECL_ASSEMBLER_NAME (node->thunk.alias)
+		      : get_alias_symbol (node->decl));
   for (vnode = varpool_nodes; vnode; vnode = vnode->next)
-    if (vnode->alias && vnode->alias_of && DECL_EXTERNAL (vnode->decl)
+    if (vnode->alias && DECL_EXTERNAL (vnode->decl)
         && !TREE_ASM_WRITTEN (vnode->decl))
       assemble_alias (vnode->decl,
-		      DECL_ASSEMBLER_NAME (vnode->alias_of));
+		      vnode->alias_of ? DECL_ASSEMBLER_NAME (vnode->alias_of)
+		      : get_alias_symbol (vnode->decl));
 }
 
 

gcc/lto-cgraph.c

@@ -512,7 +512,13 @@ lto_output_node (struct lto_simple_output_block *ob, struct cgraph_node *node,
 		     || referenced_from_other_partition_p (&node->ref_list, set, vset)), 1);
   bp_pack_value (&bp, node->lowered, 1);
   bp_pack_value (&bp, in_other_partition, 1);
-  bp_pack_value (&bp, node->alias && !boundary_p, 1);
+  /* Real aliases in a boundary become non-aliases. However we still stream
+     alias info on weakrefs. 
+     TODO: We lose a bit of information here - when we know that variable is
+     defined in other unit, we may use the info on aliases to resolve 
+     symbol1 != symbol2 type tests that we can do only for locally defined objects
+     otherwise.  */
+  bp_pack_value (&bp, node->alias && (!boundary_p || DECL_EXTERNAL (node->decl)), 1);
   bp_pack_value (&bp, node->frequency, 2);
   bp_pack_value (&bp, node->only_called_at_startup, 1);
   bp_pack_value (&bp, node->only_called_at_exit, 1);
@@ -530,7 +536,8 @@ lto_output_node (struct lto_simple_output_block *ob, struct cgraph_node *node,
       streamer_write_uhwi_stream (ob->main_stream, node->thunk.fixed_offset);
       streamer_write_uhwi_stream (ob->main_stream, node->thunk.virtual_value);
     }
-  if ((node->alias || node->thunk.thunk_p) && !boundary_p)
+  if ((node->alias || node->thunk.thunk_p)
+      && (!boundary_p || (node->alias && DECL_EXTERNAL (node->decl))))
     {
       streamer_write_hwi_in_range (ob->main_stream, 0, 1,
 					node->thunk.alias != NULL);

gcc/lto/lto.c

@@ -1481,6 +1481,8 @@ add_varpool_node_to_partition (ltrans_partition part, struct varpool_node *vnode
 {
   varpool_node_set_iterator vsi;
 
+  vnode = varpool_variable_node (vnode, NULL);
+
   /* If NODE is already there, we have nothing to do.  */
   vsi = varpool_node_set_find (part->varpool_set, vnode);
   if (!vsi_end_p (vsi))