Always use the StoreFieldStub to do the actual storing.

src/isolate.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 <stdlib.h>
 
 #include "src/v8.h"
 
 #include "src/ast.h"
 #include "src/base/platform/platform.h"
@@ skipping 1985 matching lines @@
     ToBooleanStub::InstallDescriptors(this);
     ToNumberStub::InstallDescriptors(this);
     ArrayConstructorStubBase::InstallDescriptors(this);
     InternalArrayConstructorStubBase::InstallDescriptors(this);
     FastNewClosureStub::InstallDescriptors(this);
     FastNewContextStub::InstallDescriptors(this);
     NumberToStringStub::InstallDescriptors(this);
     StringAddStub::InstallDescriptors(this);
     RegExpConstructResultStub::InstallDescriptors(this);
     KeyedLoadGenericStub::InstallDescriptors(this);
+    StoreFieldStub::InstallDescriptors(this);
   }
 
   CallDescriptors::InitializeForIsolate(this);
 
   initialized_from_snapshot_ = (des != NULL);
 
   return true;
 }
 
 
@@ skipping 350 matching lines @@
   if (prev_ && prev_->Intercept(flag)) return true;
   // Then check whether this scope intercepts.
   if ((flag & intercept_mask_)) {
     intercepted_flags_ |= flag;
     return true;
   }
   return false;
 }
 
 } }  // namespace v8::internal