Refactor how embedded pointers are visited.

src/mark-compact.h

 // Copyright 2011 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 302 matching lines @@
     ASSERT(0 <= idx_ && idx_ < kNumberOfElements);
     slots_[idx_++] = slot;
   }
 
   enum SlotType {
     RELOCATED_CODE_OBJECT,
     CODE_TARGET_SLOT,
     CODE_ENTRY_SLOT,
     DEBUG_TARGET_SLOT,
     JS_RETURN_SLOT,
+    EMBEDDED_OBJECT_SLOT,

[Vyacheslav Egorov (Chromium), 2011/10/12 14:21:53]

micro opt idea: consider placing it first (or in the middle) depending on the
way switch over slot types is compiled in visit function (rationale: there are
currently much more EMBEDDED_OBJECT_SLOTs than anything else)

[Michael Starzinger, 2011/10/12 15:38:36]

Done. On both ia32 and x64 it is compiled as a lookup table. But I placed it
first to indicate (syntactically) that it is the most frequent type.

     NUMBER_OF_SLOT_TYPES
   };
 
   void UpdateSlots(Heap* heap);
 
   void UpdateSlotsWithFilter(Heap* heap);
 
   SlotsBuffer* next() { return next_; }
 
   static int SizeOfChain(SlotsBuffer* buffer) {
@@ skipping 200 matching lines @@
     // pointers to evacuated objects.
     if (page->owner()->identity() == OLD_DATA_SPACE) {
       evacuation_candidates_.RemoveElement(page);
     } else {
       page->SetFlag(Page::RESCAN_ON_EVACUATION);
     }
   }
 
   void RecordRelocSlot(RelocInfo* rinfo, Code* target);
   void RecordCodeEntrySlot(Address slot, Code* target);
+  void RecordEmbeddedSlot(RelocInfo* rinfo, Object* target);
 
   INLINE(void RecordSlot(Object** anchor_slot, Object** slot, Object* object));
 
   void MigrateObject(Address dst,
                      Address src,
                      int size,
                      AllocationSpace to_old_space);
 
   bool TryPromoteObject(HeapObject* object, int object_size);
 
@@ skipping 231 matching lines @@
 
   friend class Heap;
 };
 
 
 const char* AllocationSpaceName(AllocationSpace space);
 
 } }  // namespace v8::internal
 
 #endif  // V8_MARK_COMPACT_H_