revert: re PR lto/48437 (LTO crashes with block-local function declarations)

2012-12-15  Richard Guenther  <rguenther@suse.de>

	Revert
	PR lto/48437
	* lto-streamer-out.c (tree_is_indexable): Exclude block-local
	extern declarations.

	PR lto/48508
	PR lto/48437
	* tree-streamer-out.c (streamer_write_chain): Stream DECL_EXTERNAL
	VAR_DECLs and FUNCTION_DECLs locally.

	* g++.dg/lto/pr48508-1_0.C: New testcase.
	* g++.dg/lto/pr48508-1_1.C: Likewise.

From-SVN: r182358

gcc/ChangeLog

+2012-12-15  Richard Guenther  <rguenther@suse.de>
+
+	Revert
+	PR lto/48437
+	* lto-streamer-out.c (tree_is_indexable): Exclude block-local
+	extern declarations.
+
+	PR lto/48508
+	PR lto/48437
+	* tree-streamer-out.c (streamer_write_chain): Stream DECL_EXTERNAL
+	VAR_DECLs and FUNCTION_DECLs locally.
+
 2011-12-14  Richard Henderson  <rth@redhat.com>
 
 	* config/arm/arm.md (*addsi3_compare0_scratch): Set predicable.

gcc/lto-streamer-out.c

@@ -129,16 +129,6 @@ tree_is_indexable (tree t)
   else if (TREE_CODE (t) == VAR_DECL && decl_function_context (t)
 	   && !TREE_STATIC (t))
     return false;
-  /* If this is a decl generated for block local externs for
-     debug info generation, stream it unshared alongside BLOCK_VARS.  */
-  else if (VAR_OR_FUNCTION_DECL_P (t)
-	   /* ???  The following tests are a literal match on what
-	      c-decl.c:pop_scope does.  */
-	   && TREE_PUBLIC (t)
-	   && DECL_EXTERNAL (t)
-	   && DECL_CONTEXT (t)
-	   && TREE_CODE (DECL_CONTEXT (t)) == FUNCTION_DECL)
-    return false;
   /* Variably modified types need to be streamed alongside function
      bodies because they can refer to local entities.  Together with
      them we have to localize their members as well.

gcc/testsuite/ChangeLog

+2012-12-15  Richard Guenther  <rguenther@suse.de>
+
+	PR lto/48508
+	* g++.dg/lto/pr48508-1_0.C: New testcase.
+	* g++.dg/lto/pr48508-1_1.C: Likewise.
+
 2011-12-14  Jason Merrill  <jason@redhat.com>
 
 	PR c++/51554

gcc/testsuite/g++.dg/lto/pr48508-1_0.C

+// { dg-lto-do link }
+// { dg-lto-options { { -g -O2 -flto -flto-partition=none } } }
+
+void __attribute__((externally_visible))
+foo (int i)
+{
+}

gcc/testsuite/g++.dg/lto/pr48508-1_1.C

+static void
+bar (void)
+{
+  extern void foo (int);
+  foo (0);
+}
+int main()
+{
+  bar ();
+}

gcc/tree-streamer-out.c

@@ -405,7 +405,13 @@ streamer_write_chain (struct output_block *ob, tree t, bool ref_p)
       saved_chain = TREE_CHAIN (t);
       TREE_CHAIN (t) = NULL_TREE;
 
-      stream_write_tree (ob, t, ref_p);
+      /* We avoid outputting external vars or functions by reference
+	 to the global decls section as we do not want to have them
+	 enter decl merging.  This is, of course, only for the call
+	 for streaming BLOCK_VARS, but other callers are safe.  */
+      stream_write_tree (ob, t,
+			 ref_p && !(VAR_OR_FUNCTION_DECL_P (t)
+				    && DECL_EXTERNAL (t)));
 
       TREE_CHAIN (t) = saved_chain;
       t = TREE_CHAIN (t);