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
 // met:
 //
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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 (!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);
+    StaticVisitor::VisitPointer(heap, rinfo->target_object_address());

[Michael Starzinger, 2013/06/20 12:40:34]

Yes, this approach will work. But it requires a trailing update of the target
object, because on some architectures you are not going to get a direct pointer
into the code because the embedded object is stored split accross several
instructions. Something like the following is needed.

Look at PointersUpdatingVisitor::VisitEmbeddedPointer() for an example of how
this can be done.

   }
 }
 
 
 template<typename StaticVisitor>
 void StaticMarkingVisitor<StaticVisitor>::VisitCell(
     Heap* heap, RelocInfo* rinfo) {
   ASSERT(rinfo->rmode() == RelocInfo::CELL);
   Cell* cell = rinfo->target_cell();
   StaticVisitor::MarkObject(heap, cell);
@@ skipping 564 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_