Short-circuit embedded cons strings.

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 6c3c9d44fe318d77c141a68dc6d562d86563aceb..ccd76a0fd63df3623c95fdda89dfc1ee288c890e 100644
--- a/src/objects-visiting-inl.h
+++ b/src/objects-visiting-inl.h
@@ -233,8 +233,12 @@ template<typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::VisitEmbeddedPointer(
     Heap* heap, RelocInfo* rinfo) {
   ASSERT(rinfo->rmode() == RelocInfo::EMBEDDED_OBJECT);
-  ASSERT(!rinfo->target_object()->IsConsString());
   HeapObject* object = HeapObject::cast(rinfo->target_object());
+  if (object->IsConsString() && ConsString::cast(object)->IsFlat()) {

[Michael Starzinger, 2013/06/20 10:04:13]

I don't think this is the correct place to do the short-circuit strings. It's
not feasible to add a special check for IsConstString() to every iterator that
could potentially encounter a cons string. This needs to be done by the actual
visitor function. I'll look into a cleaner solution for this.

+    // Short-circuit flattened cons-strings.
+    object = ConsString::cast(object)->first();
+    rinfo->set_target_object(object);
+  }
   if (!FLAG_weak_embedded_maps_in_optimized_code || !FLAG_collect_maps ||
       rinfo->host()->kind() != Code::OPTIMIZED_FUNCTION ||
       !object->IsMap() || !Map::cast(object)->CanTransition()) {