Add map-based read barrier to WeakCell

src/heap/heap.cc

 // 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.
 
 #include "src/v8.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/base/bits.h"
 #include "src/base/once.h"
@@ skipping 2685 matching lines @@
 
     TYPED_ARRAYS(ALLOCATE_FIXED_TYPED_ARRAY_MAP)
 #undef ALLOCATE_FIXED_TYPED_ARRAY_MAP
 
     ALLOCATE_VARSIZE_MAP(FIXED_ARRAY_TYPE, sloppy_arguments_elements)
 
     ALLOCATE_VARSIZE_MAP(CODE_TYPE, code)
 
     ALLOCATE_MAP(CELL_TYPE, Cell::kSize, cell)
     ALLOCATE_MAP(PROPERTY_CELL_TYPE, PropertyCell::kSize, global_property_cell)
-    ALLOCATE_MAP(WEAK_CELL_TYPE, WeakCell::kSize, weak_cell)
+    ALLOCATE_MAP(WEAK_CELL_TYPE, WeakCell::kSize, used_weak_cell)
+    ALLOCATE_MAP(WEAK_CELL_TYPE, WeakCell::kSize, unused_weak_cell)
     ALLOCATE_MAP(FILLER_TYPE, kPointerSize, one_pointer_filler)
     ALLOCATE_MAP(FILLER_TYPE, 2 * kPointerSize, two_pointer_filler)
 
 
     for (unsigned i = 0; i < arraysize(struct_table); i++) {
       const StructTable& entry = struct_table[i];
       Map* map;
       if (!AllocateMap(entry.type, entry.size).To(&map)) return false;
       roots_[entry.index] = map;
     }
@@ skipping 116 matching lines @@
 
 AllocationResult Heap::AllocateWeakCell(HeapObject* value) {
   int size = WeakCell::kSize;
   STATIC_ASSERT(WeakCell::kSize <= Page::kMaxRegularHeapObjectSize);
   HeapObject* result;
   {
     AllocationResult allocation =
         AllocateRaw(size, OLD_POINTER_SPACE, OLD_POINTER_SPACE);
     if (!allocation.To(&result)) return allocation;
   }
-  result->set_map_no_write_barrier(weak_cell_map());
+  result->set_map_no_write_barrier(used_weak_cell_map());
   WeakCell::cast(result)->initialize(value);
   WeakCell::cast(result)->set_next(undefined_value(), SKIP_WRITE_BARRIER);
   return result;
 }
 
 
 void Heap::CreateApiObjects() {
   HandleScope scope(isolate());
   Factory* factory = isolate()->factory();
   Handle<Map> new_neander_map =
@@ skipping 3633 matching lines @@
       static_cast<int>(object_sizes_last_time_[index]));
   CODE_AGE_LIST_COMPLETE(ADJUST_LAST_TIME_OBJECT_COUNT)
 #undef ADJUST_LAST_TIME_OBJECT_COUNT
 
   MemCopy(object_counts_last_time_, object_counts_, sizeof(object_counts_));
   MemCopy(object_sizes_last_time_, object_sizes_, sizeof(object_sizes_));
   ClearObjectStats();
 }
 }
 }  // namespace v8::internal