Short-circuit embedded cons strings.

src/objects-visiting-inl.h

 // Copyright 2012 the V8 project authors. All rights reserved.
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 // modification, are permitted provided that the following conditions are
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 //
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@@ skipping 215 matching lines @@
   Code* code = Code::cast(Code::GetObjectFromEntryAddress(entry_address));
   heap->mark_compact_collector()->RecordCodeEntrySlot(entry_address, code);
   StaticVisitor::MarkObject(heap, code);
 }
 
 
 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()) {
     heap->mark_compact_collector()->RecordRelocSlot(rinfo, object);
     StaticVisitor::MarkObject(heap, object);
   }
 }
 
 
 template<typename StaticVisitor>
@@ skipping 569 matching lines @@
   RelocIterator it(this, mode_mask);
   for (; !it.done(); it.next()) {
     it.rinfo()->template Visit<StaticVisitor>(heap);
   }
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_VISITING_INL_H_