Allow FastCloneShallowObjectStub to use AllocationMementos.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 99687caf91e9963727301762e6ce2d2f61af1974..ceb3a61176a42ad0a8ff62878c2c1c0565eeb79d 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -4335,15 +4335,23 @@ void HOptimizedGraphBuilder::VisitObjectLiteral(ObjectLiteral* expr) {
 
   // Check whether to use fast or slow deep-copying for boilerplate.
   int max_properties = kMaxFastLiteralProperties;
-  Handle<Object> boilerplate(closure->literals()->get(
-      expr->literal_index()), isolate());
-  if (boilerplate->IsJSObject() &&
-      IsFastLiteral(Handle<JSObject>::cast(boilerplate),
+  Handle<Object> literals_cell(closure->literals()->get(expr->literal_index()),
+                               isolate());
+  Handle<AllocationSite> site;
+  Handle<JSObject> boilerplate;
+  if (!literals_cell->IsUndefined()) {
+    // Retrieve the boilerplate
+    ASSERT(literals_cell->IsAllocationSite());

[Michael Starzinger, 2013/10/11 07:49:37]

nit: Assert is not needed, the cast below will do one for you.

[mvstanton, 2013/10/11 09:23:47]

Done.

+    site = Handle<AllocationSite>::cast(literals_cell);
+    boilerplate = Handle<JSObject>(JSObject::cast(site->transition_info()),
+                                   isolate());
+  }
+
+  if (!boilerplate.is_null() &&
+      IsFastLiteral(boilerplate,

[Michael Starzinger, 2013/10/11 07:49:37]

nit: Second predicate should fit into one line now.

[mvstanton, 2013/10/11 09:23:47]

Done.

                     kMaxFastLiteralDepth,
                     &max_properties)) {
-    Handle<JSObject> boilerplate_object = Handle<JSObject>::cast(boilerplate);
-
-    literal = BuildFastLiteral(boilerplate_object);
+    literal = BuildFastLiteral(boilerplate);
   } else {
     NoObservableSideEffectsScope no_effects(this);
     Handle<FixedArray> closure_literals(closure->literals(), isolate());