Use weak cells in CheckPropertyCell.

src/ic/x64/handler-compiler-x64.cc

 // Copyright 2014 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"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/ic/call-optimization.h"
 #include "src/ic/handler-compiler.h"
@@ skipping 193 matching lines @@
   CallApiAccessorStub stub(isolate, is_store, call_data_undefined);
   __ TailCallStub(&stub);
 }
 
 
 void PropertyHandlerCompiler::GenerateCheckPropertyCell(
     MacroAssembler* masm, Handle<JSGlobalObject> global, Handle<Name> name,
     Register scratch, Label* miss) {
   Handle<PropertyCell> cell = JSGlobalObject::EnsurePropertyCell(global, name);
   DCHECK(cell->value()->IsTheHole());
-  __ Move(scratch, cell);
-  __ Cmp(FieldOperand(scratch, Cell::kValueOffset),
-         masm->isolate()->factory()->the_hole_value());
+  Factory* factory = masm->isolate()->factory();
+  Handle<WeakCell> weak_cell = factory->NewWeakCell(cell);
+  __ LoadWeakValue(scratch, weak_cell, miss);
+  __ Cmp(FieldOperand(scratch, Cell::kValueOffset), factory->the_hole_value());
   __ j(not_equal, miss);
 }
 
 
 void NamedStoreHandlerCompiler::GenerateStoreViaSetter(
     MacroAssembler* masm, Handle<HeapType> type, Register receiver,
     Register holder, int accessor_index, int expected_arguments,
     Register scratch) {
   // ----------- S t a t e -------------
   //  -- rsp[0] : return address
@@ skipping 535 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64