Make cells pointing to JSObjects weak in optimized code.

src/objects-visiting-inl.h

Index: src/objects-visiting-inl.h
diff --git a/src/objects-visiting-inl.h b/src/objects-visiting-inl.h
index 1a68344b26a6782f83c9e4661b6a8f4e9831d402..965fda5713ddf363c04f85edeace5cd4ac6d3d79 100644
--- a/src/objects-visiting-inl.h
+++ b/src/objects-visiting-inl.h
@@ -272,7 +272,9 @@ void StaticMarkingVisitor<StaticVisitor>::VisitCell(
     Heap* heap, RelocInfo* rinfo) {
   ASSERT(rinfo->rmode() == RelocInfo::CELL);
   Cell* cell = rinfo->target_cell();
-  StaticVisitor::MarkObject(heap, cell);
+  if (!Code::IsWeakEmbeddedObject(rinfo->host()->kind(), cell)) {

[Michael Starzinger, 2014/01/10 13:45:19]

As discussed offline: We do not record slots in code that point to cells. That
is _only_ correct because we don't compact cell space. We should put a comment
here explaining this, so that we remember once fragmentation of cell space
becomes an issue.

[ulan, 2014/01/13 11:35:06]

Done.

+    StaticVisitor::MarkObject(heap, cell);
+  }
 }