Simple non-incremental compaction by evacuation.

src/store-buffer.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 58 matching lines @@
   // we are rebuilding the store buffer using this function.  There is, however
   // no issue of overwriting the buffer we are iterating over, because this
   // stage of the scavenge can only reduce the number of addresses in the store
   // buffer (some objects are promoted so pointers to them do not need to be in
   // the store buffer).  The later parts of the GC scan the pages that are
   // exempt from the store buffer and process the promotion queue.  These steps
   // can overflow this buffer.  We check for this and on overflow we call the
   // callback set up with the StoreBufferRebuildScope object.
   inline void EnterDirectlyIntoStoreBuffer(Address addr);
 
+
+  enum IterationMode {
+    SKIP_SLOTS_IN_EVACUATION_CANDIDATES,
+    VISIT_ALL_SLOTS
+  };
+
   // Iterates over all pointers that go from old space to new space.  It will
   // delete the store buffer as it starts so the callback should reenter
   // surviving old-to-new pointers into the store buffer to rebuild it.
-  void IteratePointersToNewSpace(ObjectSlotCallback callback);
+  void IteratePointersToNewSpace(ObjectSlotCallback callback,
+                                 IterationMode mode);
 
   static const int kStoreBufferOverflowBit = 1 << 16;
   static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
   static const int kOldStoreBufferLength = kStoreBufferLength * 64;
   static const int kHashMapLengthLog2 = 12;
   static const int kHashMapLength = 1 << kHashMapLengthLog2;
 
   void Compact();
   static void GCPrologue(GCType type, GCCallbackFlags flags);
@@ skipping 84 matching lines @@
     Address start,
     Address end,
     ObjectSlotCallback slot_callback);
 
   void FindPointersToNewSpaceOnPage(
     PagedSpace* space,
     Page* page,
     RegionCallback region_callback,
     ObjectSlotCallback slot_callback);
 
+  template<StoreBuffer::IterationMode mode>
+  void IteratePointersInStoreBuffer(ObjectSlotCallback slot_callback);
+
+
 #ifdef DEBUG
   void VerifyPointers(PagedSpace* space, RegionCallback region_callback);
   void VerifyPointers(LargeObjectSpace* space);
 #endif
 
   friend class StoreBufferRebuildScope;
   friend class DontMoveStoreBufferEntriesScope;
 };
 
 
@@ skipping 38 matching lines @@
   }
 
  private:
   StoreBuffer* store_buffer_;
   bool stored_state_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_STORE_BUFFER_H_