Filter out invalid slots in store buffer eagerly during object transition.

src/heap/store-buffer.h

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_STORE_BUFFER_H_
 #define V8_STORE_BUFFER_H_
 
 #include "src/allocation.h"
 #include "src/base/logging.h"
 #include "src/base/platform/platform.h"
@@ skipping 18 matching lines @@
   void SetUp();
   void TearDown();
 
   static const int kStoreBufferOverflowBit = 1 << (14 + kPointerSizeLog2);
   static const int kStoreBufferSize = kStoreBufferOverflowBit;
   static const int kStoreBufferLength = kStoreBufferSize / sizeof(Address);
 
   // This is used to add addresses to the store buffer non-concurrently.
   inline void Mark(Address addr);
 
+  // Removes the given slot from the store buffer non-concurrently. If the
+  // slot was never added to the store buffer, then the function does nothing.
+  void Remove(Address addr);
+
   // Slots that do not point to the ToSpace after callback invocation will be
   // removed from the set.
   void IteratePointersToNewSpace(ObjectSlotCallback callback);
 
   void Verify();
 
   // Eliminates all stale store buffer entries from the store buffer, i.e.,
   // slots that are not part of live objects anymore. This method must be
   // called after marking, when the whole transitive closure is known and
   // must be called before sweeping when mark bits are still intact.
@@ skipping 56 matching lines @@
     int count;
   };
 
   Node* top_;
 };
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_STORE_BUFFER_H_