re PR lto/61886 (LTO breaks fread with _FORTIFY_SOURCE=2)

	PR ipa/61886
	* symtab.c (ultimate_transparent_alias_target): New inline function.
	(symbol_table::assembler_names_equal_p): New method; break out from ...
	(symbol_table::decl_assembler_name_equal): ... here.
	(symbol_table::change_decl_assembler_name): Also update names and
	translation links of transparent aliases.
	(symtab_node::dump_base): Dump transparent_alias.
	(symtab_node::verify_base): Implement basic transparent alias
	verification.
	(symtab_node::make_decl_local): Support localization of weakrefs;
	recurse to transparent aliases; set TREE_STATIC.
	(symtab_node::ultimate_alias_target_1): Handle visibility of
	transparent aliases.
	(symtab_node::resolve_alias): New parmaeter transparent; handle
	transparent aliases; recurse to aliases of aliases to fix comdat
	groups.
	(symtab_node::get_partitioning_class): Handle transparent aliases.
	* ipa-visibility.c (cgraph_externally_visible_p,
	varpool_node::externally_visible_p): Visibility of transparent alias
	depends on its target.
	(function_and_variable_visibility): Do not tweak visibility of
	transparent laiases.
	(function_and_variable_visibility): Likewise.
	* ipa.c (symbol_table::remove_unreachable_nodes): Clear
	transparent_alias flag.
	* alias.c (cgraph_node::create_alias, cgraph_node::get_availability):
	Support transparent aliases.
	* cgraph.h (symtab_node): Update prototype of resolve_alias;
	add transparent_alias flag.
	(symbol_table: Add assembler_names_equal_p.
	(symtab_node::real_symbol_p): Skip transparent aliases.
	* cgraphunit.c (cgraph_node::reset): Reset transparent_alias flag.
	(handle_alias_pairs): Set transparent_alias for weakref.
	(cgraph_node::assemble_thunks_and_aliases): Do not asemble transparent
	aliases.
	* lto-cgraph.c (lto_output_node): When outputting same_comdat_group
	skip symbols not put into boundary; stream transparent_alias.
	(lto_output_varpool_node): Likewise.
	(input_overwrite_node, input_varpool_node): Stream transparent alias.
	* varpool.c (ctor_for_folding, varpool_node::get_availability,
	varpool_node::assemble_aliases,
	symbol_table::remove_unreferenced_decls): Handle transparent aliase.
	(varpool_node::create_alias): Set transparent_alias.

	* lto-partition.c (add_symbol_to_partition_1, contained_in_symbol,
	rename_statics, rename_statics): Handle transparent aliases.

From-SVN: r231373

1 files changed, 15 insertions, 7 deletions

diff --git a/gcc/varpool.c b/gcc/varpool.c
index 36f19a62ba8..ffbec6d727a 100644
--- a/gcc/varpool.c
+++ b/gcc/varpool.c
@@ -440,7 +440,7 @@ ctor_for_folding (tree decl)
       gcc_assert (!DECL_INITIAL (decl)
 		  || (node->alias && node->get_alias_target () == real_node)
 		  || DECL_INITIAL (decl) == error_mark_node);
-      if (node->weakref)
+      while (node->transparent_alias && node->analyzed)
 	{
 	  node = node->get_alias_target ();
 	  decl = node->decl;
@@ -490,11 +490,11 @@ varpool_node::get_availability (void)
   if (DECL_IN_CONSTANT_POOL (decl)
       || DECL_VIRTUAL_P (decl))
     return AVAIL_AVAILABLE;
-  if (alias && weakref)
+  if (transparent_alias)
     {
       enum availability avail;
 
-      ultimate_alias_target (&avail)->get_availability ();
+      ultimate_alias_target (&avail);
       return avail;
     }
   /* If the variable can be overwritten, return OVERWRITABLE.  Takes
@@ -536,8 +536,9 @@ varpool_node::assemble_aliases (void)
   FOR_EACH_ALIAS (this, ref)
     {
       varpool_node *alias = dyn_cast <varpool_node *> (ref->referring);
-      do_assemble_alias (alias->decl,
-			 DECL_ASSEMBLER_NAME (decl));
+      if (!alias->transparent_alias)
+	do_assemble_alias (alias->decl,
+			   DECL_ASSEMBLER_NAME (decl));
       alias->assemble_aliases ();
     }
 }
@@ -665,7 +666,14 @@ symbol_table::remove_unreferenced_decls (void)
 	      && vnode->analyzed)
 	    enqueue_node (vnode, &first);
 	  else
-	    referenced.add (node);
+	    {
+	      referenced.add (node);
+	      while (node->alias && node->definition)
+		{
+		  node = node->get_alias_target ();
+	          referenced.add (node);
+		}
+	    }
 	}
     }
   if (dump_file)
@@ -760,7 +768,7 @@ varpool_node::create_alias (tree alias, tree decl)
   alias_node->definition = true;
   alias_node->alias_target = decl;
   if (lookup_attribute ("weakref", DECL_ATTRIBUTES (alias)) != NULL)
-    alias_node->weakref = true;
+    alias_node->weakref = alias_node->transparent_alias = true;
   return alias_node;
 }