Use weak cells to embed maps in store handler.

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 306 matching lines @@
 
 void NamedStoreHandlerCompiler::GenerateRestoreName(Label* label,
                                                     Handle<Name> name) {
   if (!label->is_unused()) {
     __ bind(label);
     __ Move(this->name(), name);
   }
 }
 
 
-void NamedStoreHandlerCompiler::GenerateRestoreNameAndMap(
-    Handle<Name> name, Handle<Map> transition) {
+void NamedStoreHandlerCompiler::GenerateRestoreName(Handle<Name> name) {
   __ Move(this->name(), name);
-  __ Move(StoreTransitionDescriptor::MapRegister(), transition);
 }
 
 
+void NamedStoreHandlerCompiler::GenerateRestoreMap(Handle<Map> transition,
+                                                   Register scratch,
+                                                   Label* miss) {
+  Handle<WeakCell> cell = Map::WeakCellForMap(transition);
+  Register map_reg = StoreTransitionDescriptor::MapRegister();
+  DCHECK(!map_reg.is(scratch));
+  __ LoadWeakValue(map_reg, cell, miss);
+  if (transition->CanBeDeprecated()) {
+    __ movl(scratch, FieldOperand(map_reg, Map::kBitField3Offset));
+    __ andl(scratch, Immediate(Map::Deprecated::kMask));
+    __ j(not_zero, miss);
+  }
+}
+
 void NamedStoreHandlerCompiler::GenerateConstantCheck(Object* constant,
                                                       Register value_reg,
                                                       Label* miss_label) {
   __ Cmp(value_reg, handle(constant, isolate()));
   __ j(not_equal, miss_label);
 }
 
 
 void NamedStoreHandlerCompiler::GenerateFieldTypeChecks(HeapType* field_type,
                                                         Register value_reg,
@@ skipping 341 matching lines @@
   // Return the generated code.
   return GetCode(kind(), Code::NORMAL, name);
 }
 
 
 #undef __
 }
 }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64