Virtually dispatched specialized scavengers.

src/objects.h

 // Copyright 2006-2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 2881 matching lines @@
   static const int kFlagsCacheInPrototypeMapMask = 0x00000800;
   static const int kFlagsArgumentsCountMask = 0xFFFFF000;
 
   static const int kFlagsNotUsedInLookup =
       (kFlagsICInLoopMask | kFlagsTypeMask | kFlagsCacheInPrototypeMapMask);
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(Code);
 };
 
+typedef void (*Scavenger)(Map* map, HeapObject** slot, HeapObject* object);
 
 // All heap objects have a Map that describes their structure.
 //  A Map contains information about:
 //  - Size information about the object
 //  - How to iterate over an object (for garbage collection)
 class Map: public HeapObject {
  public:
   // Instance size.
   inline int instance_size();
   inline void set_instance_size(int value);
@@ skipping 181 matching lines @@
   // following back pointers.
   void ClearNonLiveTransitions(Object* real_prototype);
 
   // Dispatched behavior.
   void MapIterateBody(ObjectVisitor* v);
 #ifdef DEBUG
   void MapPrint();
   void MapVerify();
 #endif
 
+  inline Scavenger scavenger();
+  inline void set_scavenger(Scavenger callback);
+
+  inline void Scavenge(HeapObject** slot, HeapObject* obj) {
+    scavenger()(this, slot, obj);
+  }
+
   static const int kMaxPreAllocatedPropertyFields = 255;
 
   // Layout description.
   static const int kInstanceSizesOffset = HeapObject::kHeaderSize;
   static const int kInstanceAttributesOffset = kInstanceSizesOffset + kIntSize;
   static const int kPrototypeOffset = kInstanceAttributesOffset + kIntSize;
   static const int kConstructorOffset = kPrototypeOffset + kPointerSize;
   static const int kInstanceDescriptorsOffset =
       kConstructorOffset + kPointerSize;
   static const int kCodeCacheOffset = kInstanceDescriptorsOffset + kPointerSize;
-  static const int kPadStart = kCodeCacheOffset + kPointerSize;
+  static const int kIterateBodyCallbackOffset = kCodeCacheOffset + kPointerSize;
+  static const int kPadStart = kIterateBodyCallbackOffset + kPointerSize;
   static const int kSize = MAP_POINTER_ALIGN(kPadStart);
 
   // Layout of pointer fields. Heap iteration code relies on them
   // being continiously allocated.
   static const int kPointerFieldsBeginOffset = Map::kPrototypeOffset;
   static const int kPointerFieldsEndOffset =
       Map::kCodeCacheOffset + kPointerSize;
 
   // Byte offsets within kInstanceSizesOffset.
   static const int kInstanceSizeOffset = kInstanceSizesOffset + 0;
@@ skipping 2233 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_