Add map-based read barrier to WeakCell

src/objects.h

 // Copyright 2012 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_OBJECTS_H_
 #define V8_OBJECTS_H_
 
 #include <iosfwd>
 
 #include "src/allocation.h"
@@ skipping 2584 matching lines @@
  public:
   enum SearchForDuplicates { kAlwaysAdd, kAddIfNotFound };
 
   // If |maybe_array| is not a WeakFixedArray, a fresh one will be allocated.
   static Handle<WeakFixedArray> Add(
       Handle<Object> maybe_array, Handle<HeapObject> value,
       SearchForDuplicates search_for_duplicates = kAlwaysAdd);
 
   void Remove(Handle<HeapObject> value);
 
-  inline Object* Get(int index) const;
+  inline Object* Get(Heap* heap, int index) const;
   inline int Length() const;
 
   DECLARE_CAST(WeakFixedArray)
 
  private:
   static const int kLastUsedIndexIndex = 0;
   static const int kFirstIndex = 1;
 
   static Handle<WeakFixedArray> Allocate(
       Isolate* isolate, int size, Handle<WeakFixedArray> initialize_from);
 
   static void Set(Handle<WeakFixedArray> array, int index,
                   Handle<HeapObject> value);
+  inline bool EqualAt(int index, Object* object) const;
   inline void clear(int index);
   inline bool IsEmptySlot(int index) const;
 
   inline int last_used_index() const;
   inline void set_last_used_index(int index);
 
   // Disallow inherited setters.
   void set(int index, Smi* value);
   void set(int index, Object* value);
   void set(int index, Object* value, WriteBarrierMode mode);
@@ skipping 7126 matching lines @@
                               kSize> BodyDescriptor;
 
  private:
   DECL_ACCESSORS(type_raw, Object)
   DISALLOW_IMPLICIT_CONSTRUCTORS(PropertyCell);
 };
 
 
 class WeakCell : public HeapObject {
  public:
-  inline Object* value() const;
+  inline Object* value(Heap* heap);
+  inline Object* ValueNoReadBarrier();
 
   // This should not be called by anyone except GC.
   inline void clear();
 
   // This should not be called by anyone except allocator.
   inline void initialize(HeapObject* value);
 
   inline bool cleared() const;
 
   DECL_ACCESSORS(next, Object)
 
   DECLARE_CAST(WeakCell)
 
   DECLARE_PRINTER(WeakCell)
   DECLARE_VERIFIER(WeakCell)
 
   // Layout description.
-  static const int kValueOffset = HeapObject::kHeaderSize;
-  static const int kNextOffset = kValueOffset + kPointerSize;
+  static const int kValueOffsetDontForgetTheReadBarrier =
+      HeapObject::kHeaderSize;
+  static const int kNextOffset =
+      kValueOffsetDontForgetTheReadBarrier + kPointerSize;
   static const int kSize = kNextOffset + kPointerSize;
 
-  typedef FixedBodyDescriptor<kValueOffset, kSize, kSize> BodyDescriptor;
+  static inline void TriggerReadBarrier(Object* possible_weak_cell);
+
+  typedef FixedBodyDescriptor<kValueOffsetDontForgetTheReadBarrier, kSize,
+                              kSize> BodyDescriptor;
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(WeakCell);
 };
 
 
 // The JSProxy describes EcmaScript Harmony proxies
 class JSProxy: public JSReceiver {
  public:
   // [handler]: The handler property.
@@ skipping 1178 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_