Add map-based read barrier to WeakCell

src/heap/heap.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_HEAP_HEAP_H_
 #define V8_HEAP_HEAP_H_
 
 #include <cmath>
 
 #include "src/allocation.h"
@@ skipping 34 matching lines @@
   V(Map, meta_map, MetaMap)                                                    \
   V(Map, heap_number_map, HeapNumberMap)                                       \
   V(Map, mutable_heap_number_map, MutableHeapNumberMap)                        \
   V(Map, native_context_map, NativeContextMap)                                 \
   V(Map, fixed_array_map, FixedArrayMap)                                       \
   V(Map, code_map, CodeMap)                                                    \
   V(Map, scope_info_map, ScopeInfoMap)                                         \
   V(Map, fixed_cow_array_map, FixedCOWArrayMap)                                \
   V(Map, fixed_double_array_map, FixedDoubleArrayMap)                          \
   V(Map, constant_pool_array_map, ConstantPoolArrayMap)                        \
-  V(Map, weak_cell_map, WeakCellMap)                                           \
+  V(Map, used_weak_cell_map, UsedWeakCellMap)                                  \
+  V(Map, unused_weak_cell_map, UnusedWeakCellMap)                              \
   V(Oddball, no_interceptor_result_sentinel, NoInterceptorResultSentinel)      \
   V(Map, hash_table_map, HashTableMap)                                         \
   V(Map, ordered_hash_table_map, OrderedHashTableMap)                          \
   V(FixedArray, empty_fixed_array, EmptyFixedArray)                            \
   V(ByteArray, empty_byte_array, EmptyByteArray)                               \
   V(DescriptorArray, empty_descriptor_array, EmptyDescriptorArray)             \
   V(ConstantPoolArray, empty_constant_pool_array, EmptyConstantPoolArray)      \
   V(Oddball, arguments_marker, ArgumentsMarker)                                \
   /* The roots above this line should be boring from a GC point of view.    */ \
   /* This means they are never in new space and never on a page that is     */ \
@@ skipping 269 matching lines @@
   V(MetaMap)                            \
   V(HeapNumberMap)                      \
   V(MutableHeapNumberMap)               \
   V(NativeContextMap)                   \
   V(FixedArrayMap)                      \
   V(CodeMap)                            \
   V(ScopeInfoMap)                       \
   V(FixedCOWArrayMap)                   \
   V(FixedDoubleArrayMap)                \
   V(ConstantPoolArrayMap)               \
-  V(WeakCellMap)                        \
+  V(UsedWeakCellMap)                    \
+  V(UnusedWeakCellMap)                  \
   V(NoInterceptorResultSentinel)        \
   V(HashTableMap)                       \
   V(OrderedHashTableMap)                \
   V(EmptyFixedArray)                    \
   V(EmptyByteArray)                     \
   V(EmptyDescriptorArray)               \
   V(EmptyConstantPoolArray)             \
   V(ArgumentsMarker)                    \
   V(SymbolMap)                          \
   V(SloppyArgumentsElementsMap)         \
@@ skipping 2232 matching lines @@
   DisallowHeapAllocation no_allocation;  // i.e. no gc allowed.
 
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(PathTracer);
 };
 #endif  // DEBUG
 }
 }  // namespace v8::internal
 
 #endif  // V8_HEAP_HEAP_H_