Merge r10334 from the bleeding_edge to the 3.7 branch.

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 67 matching lines @@
 
   // 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);
 
   static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
   static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
   static const int kOldStoreBufferLength = kStoreBufferLength * 16;
-  static const int kHashMapLengthLog2 = 12;
-  static const int kHashMapLength = 1 << kHashMapLengthLog2;
+  static const int kHashSetLengthLog2 = 12;
+  static const int kHashSetLength = 1 << kHashSetLengthLog2;
 
   void Compact();
 
   void GCPrologue();
   void GCEpilogue();
 
   Object*** Limit() { return reinterpret_cast<Object***>(old_limit_); }
   Object*** Start() { return reinterpret_cast<Object***>(old_start_); }
   Object*** Top() { return reinterpret_cast<Object***>(old_top_); }
   void SetTop(Object*** top) {
@@ skipping 39 matching lines @@
   bool old_buffer_is_filtered_;
   bool during_gc_;
   // The garbage collector iterates over many pointers to new space that are not
   // handled by the store buffer.  This flag indicates whether the pointers
   // found by the callbacks should be added to the store buffer or not.
   bool store_buffer_rebuilding_enabled_;
   StoreBufferCallback callback_;
   bool may_move_store_buffer_entries_;
 
   VirtualMemory* virtual_memory_;
-  uintptr_t* hash_map_1_;
-  uintptr_t* hash_map_2_;
+
+  // Two hash sets used for filtering.
+  // If address is in the hash set then it is guaranteed to be in the
+  // old part of the store buffer.
+  uintptr_t* hash_set_1_;
+  uintptr_t* hash_set_2_;
+  bool hash_sets_are_empty_;
+
+  void ClearFilteringHashSets();
 
   void CheckForFullBuffer();
   void Uniq();
-  void ZapHashTables();
-  bool HashTablesAreZapped();
   void ExemptPopularPages(int prime_sample_step, int threshold);
 
   void FindPointersToNewSpaceInRegion(Address start,
                                       Address end,
                                       ObjectSlotCallback slot_callback);
 
   // For each region of pointers on a page in use from an old space call
   // visit_pointer_region callback.
   // If either visit_pointer_region or callback can cause an allocation
   // in old space and changes in allocation watermark then
@@ skipping 73 matching lines @@
   }
 
  private:
   StoreBuffer* store_buffer_;
   bool stored_state_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_STORE_BUFFER_H_