Fix uninitialized memory access in WHOPR partitioning

[Jan Hubicka]

Hi,
today I got two teststuite failures with WHOPR.  Those all have just datastructures
and not functions in their WHOPR units.  This leads to uninitialied memory
access into lto_1_to_1_map since file_data variable is not initialized in varpool
processing loop (so till now we get all varpool nodes in the same partition
as last cgraph node got).

This patch adds symemtric lto_file_data filed to varpool node as we do have for
cgraph nodes.  I am not thrilled by the existence of lto_file_data pointer at
all here, isn't there some alternative to look up back file name from declaration?

Honza

	* cgraph.h (struct varpool_node): Add lto_file_data.
	* lto-cgraph.c (input_varpool_node): Set file_data.
	* lto/lto.c (lto_1_to_1_map): Use it.
Index: cgraph.h
===================================================================
--- cgraph.h	(revision 160239)
+++ cgraph.h	(working copy)
@@ -467,6 +467,9 @@ struct GTY((chain_next ("%h.next"), chai
   struct varpool_node *same_comdat_group;
   struct ipa_ref_list ref_list;
   PTR GTY ((skip)) aux;
+  /* File stream where this node is being written to.  */
+  struct lto_file_decl_data * lto_file_data;
+
   /* Ordering of all cgraph nodes.  */
   int order;
 
Index: lto-cgraph.c
===================================================================
--- lto-cgraph.c	(revision 160239)
+++ lto-cgraph.c	(working copy)
@@ -1091,6 +1091,7 @@ input_varpool_node (struct lto_file_decl
   node = varpool_node (var_decl);
 
   bp = lto_input_bitpack (ib);
+  node->lto_file_data = file_data;
   node->externally_visible = bp_unpack_value (bp, 1);
   node->force_output = bp_unpack_value (bp, 1);
   node->finalized = bp_unpack_value (bp, 1);
Index: lto/lto.c
===================================================================
--- lto/lto.c	(revision 160239)
+++ lto/lto.c	(working copy)
@@ -599,6 +599,9 @@ lto_1_to_1_map (void)
     {
       if (vnode->alias || !vnode->needed)
 	continue;
+      file_data = vnode->local.lto_file_data;
+      gcc_assert (file_data);
+      file_data = node->local.lto_file_data;
       slot = pointer_map_contains (pmap, file_data);
       if (slot)
 	partition = (ltrans_partition) *slot;