Fix lto/uniq_const testcase

[Jan Hubicka <hubicka at ucw dot cz>]

Hi,
uni-const testcase fails because we produce constant pool initializer for the
array and unify it across multiple compilation units.  Then we attempt to make
its symbol public, but because it is using internal label, we fail to link.

This patch solve the problem by keeping constant pools local to each ltrans.
At -Os we may want to revisit this in future.  OK?

Bootstrapped/regtested x86_64-linux.

	* lto-cgraph.c (lto_output_varpool_node): Always output constant pool
	references.

	* lto.c: Do not attempt to make constant pool references global.
Index: lto-cgraph.c
===================================================================
--- lto-cgraph.c	(revision 158926)
+++ lto-cgraph.c	(working copy)
@@ -375,10 +375,21 @@ lto_output_varpool_node (struct lto_simp
   gcc_assert (node->finalized || !node->analyzed);
   gcc_assert (node->needed);
   gcc_assert (!node->alias);
-  /* FIXME: We have no idea how we move references around.  For moment assume that
-     everything is used externally.  */
-  bp_pack_value (bp, flag_wpa, 1);  /* used_from_other_parition.  */
-  bp_pack_value (bp, boundary_p, 1);  /* in_other_partition.  */
+  /* Constant pool initializers can be de-unified into individual ltrans units.
+     FIXME: Alternatively at -Os we may want to avoid generating for them the local
+     labels and share them across LTRANS partitions.  */
+  if (DECL_IN_CONSTANT_POOL (node->decl))
+    {
+      bp_pack_value (bp, 0, 1);  /* used_from_other_parition.  */
+      bp_pack_value (bp, 0, 1);  /* in_other_partition.  */
+    }
+  else
+    {
+      /* FIXME: We have no idea how we move references around.  For moment assume that
+	 everything is used externally.  */
+      bp_pack_value (bp, flag_wpa, 1);  /* used_from_other_parition.  */
+      bp_pack_value (bp, boundary_p, 1);  /* in_other_partition.  */
+    }
   /* Also emit any extra name aliases.  */
   for (alias = node->extra_name; alias; alias = alias->next)
     count++;
Index: lto/lto.c
===================================================================
--- lto/lto.c	(revision 158925)
+++ lto/lto.c	(working copy)
@@ -723,9 +723,13 @@ lto_promote_cross_file_statics (void)
   gcc_assert (flag_wpa);
 
   /* At moment we make no attempt to figure out who is refering the variables,
-     so all must become global.  */
+     so all must become global.  
+
+     Constant pool references use internal labels and thus can not be made global.
+     It is sensible to keep those ltrans local to allow better optimization.  */
   for (vnode = varpool_nodes; vnode; vnode = vnode->next)
-    if (!vnode->externally_visible && vnode->analyzed)
+    if (!vnode->externally_visible && vnode->analyzed
+	&& !DECL_IN_CONSTANT_POOL (vnode->decl))
        {
 	  TREE_PUBLIC (vnode->decl) = 1;
 	  DECL_VISIBILITY (vnode->decl) = VISIBILITY_HIDDEN;