Reviewers: Michael Starzinger,
Message:
PTAL.
Description:
Clear backpointer of non-fast maps that we currently replace when a new
non-fast
type is being cached.
Please review this at https://chromiumcodereview.appspot.com/10661025/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/objects.cc
Index: src/objects.cc
diff --git a/src/objects.cc b/src/objects.cc
index
78f83c45c98ee2051b4019f47446f1e908705cae..3d883dc4e5459ace497c9a5cfb89c7a37d396566
100644
--- a/src/objects.cc
+++ b/src/objects.cc
@@ -2294,6 +2294,14 @@ MaybeObject*
Map::CreateNextElementsTransition(ElementsKind next_kind) {
this->CopyDropTransitions(DescriptorArray::CANNOT_BE_SHARED);
if (!maybe_next_map->To(&next_map)) return maybe_next_map;
+ // TODO(verwaest) For now we have to clear the backpointer of the map
we
+ // overwrite. Instead of overwriting we should rather cache all of
them.
+ Map* previous_next_map = this->elements_transition_map();
+ if (previous_next_map != NULL) {
+ ASSERT(!IsFastElementsKind(next_kind));
+ ASSERT(!IsFastElementsKind(previous_next_map->elements_kind()));
+ previous_next_map->SetBackPointer(GetHeap()->undefined_value());
+ }
next_map->set_elements_kind(next_kind);
next_map->SetBackPointer(this);
this->set_elements_transition_map(next_map);
--
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