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[LTO] Fix PR48437

Message ID alpine.LNX.2.00.1112081033210.4527@zhemvz.fhfr.qr
State New
Headers show

Commit Message

Richard Biener Dec. 8, 2011, 9:38 a.m. UTC 
On Wed, 7 Dec 2011, Diego Novillo wrote:

> On Wed, Dec 7, 2011 at 11:16, Richard Guenther <rguenther@suse.de> wrote:
> 
> > I'm going to apply it tomorrow, when full testing hopefully finished
> 
> Sure.  But remember the zombie kitties!

I have applied the fix for PR48437, the fix for PR49945 required
adjustment as otherwise we'd ICE gcc.dg/lto/20090706-1_0.c in
the type checker.  We also have to localize FIELD_DECLs of variable
size types.

Thus I'm re-testing the following and will commit that variant if it
succeeds.

I suppose at some point we need to look at the efficiency of
the variably_modified_type_p call, as tree_is_indexable is
called for each component type and variably_modified_type_p
recurses itself (thus, overall this is quadratic, but with
cheap constant factor as we are calling it with a NULL function arg).

Richard.

2011-12-08  Richard Guenther  <rguenther@suse.de>

	PR lto/49945
	* lto-streamer-out.c (tree_is_indexable): Localize variably
	modified types and their FIELD_DECLs.
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Patch

Index: gcc/lto-streamer-out.c
===================================================================
--- gcc/lto-streamer-out.c	(revision 182101)
+++ gcc/lto-streamer-out.c	(working copy)
@@ -139,6 +139,16 @@  tree_is_indexable (tree 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.
+     ???  In theory that includes non-FIELD_DECLs as well.  */
+  else if (TYPE_P (t)
+	   && variably_modified_type_p (t, NULL_TREE))
+    return false;
+  else if (TREE_CODE (t) == FIELD_DECL
+	   && variably_modified_type_p (DECL_CONTEXT (t), NULL_TREE))
+    return false;
   else
     return (TYPE_P (t) || DECL_P (t) || TREE_CODE (t) == SSA_NAME);
 }