[GOOGLE] disable streaming out TREE_BLOCK to cure lto-bootstrap

[Dehao Chen]

Hi,

The location_block patch has failed lto-bootstrap. This is fixed by a
bunch of fixes in trunk. But we would rather not spend too much effort
to back-port those fixes. So for now, we would disable streaming out
TREE_BLOCK as a workaround to solve to lto-bootstrap.

Bootstrapped and passed crosstool tests.

Okay for google-4_7?

Thanks,
Dehao

gcc/ChangeLog.google-4_7
2012-12-10  Dehao Chen  <dehao@google.com>

        * tree-streamer-out.c (write_ts_exp_tree_pointers): Disable
        streaming out TREE_BLOCK.
Index: gcc/tree-streamer-out.c
===================================================================
--- gcc/tree-streamer-out.c (revision 194378)
+++ gcc/tree-streamer-out.c (working copy)
@@ -667,7 +667,7 @@ write_ts_exp_tree_pointers (struct output_block *o
   for (i = 0; i < TREE_OPERAND_LENGTH (expr); i++)
     stream_write_tree (ob, TREE_OPERAND (expr, i), ref_p);
   lto_output_location (ob, LOCATION_LOCUS (EXPR_LOCATION (expr)));
-  stream_write_tree (ob, TREE_BLOCK (expr), ref_p);
+  stream_write_tree (ob, NULL_TREE, ref_p);
 }