Avoid TLS accesses in Object::Lookup and Object::GetPrototype.

src/property.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 165 matching lines @@
       : isolate_(isolate),
         next_(isolate->top_lookup_result()),
         lookup_type_(NOT_FOUND),
         holder_(NULL),
         cacheable_(true),
         details_(NONE, NONEXISTENT) {
     isolate->SetTopLookupResult(this);
   }
 
   ~LookupResult() {
-    ASSERT(isolate_->top_lookup_result() == this);
-    isolate_->SetTopLookupResult(next_);
+    ASSERT(isolate()->top_lookup_result() == this);
+    isolate()->SetTopLookupResult(next_);
   }
 
+  Isolate* isolate() const { return isolate_; }
+
   void DescriptorResult(JSObject* holder, PropertyDetails details, int number) {
     lookup_type_ = DESCRIPTOR_TYPE;
     holder_ = holder;
     details_ = details;
     number_ = number;
   }
 
   void TransitionResult(JSObject* holder, int number) {
     lookup_type_ = TRANSITION_TYPE;
     details_ = PropertyDetails(NONE, TRANSITION);
@@ skipping 135 matching lines @@
         }
         return value;
       }
       case CONSTANT_FUNCTION:
         return GetConstantFunction();
       case CALLBACKS:
       case HANDLER:
       case INTERCEPTOR:
       case TRANSITION:
       case NONEXISTENT:
-        return Isolate::Current()->heap()->the_hole_value();
+        return isolate()->heap()->the_hole_value();
     }
     UNREACHABLE();
     return NULL;
   }
 
   Map* GetTransitionTarget() {
     ASSERT(IsTransition());
     TransitionArray* transitions = holder()->map()->transitions();
     return transitions->GetTarget(number_);
   }
@@ skipping 103 matching lines @@
   JSReceiver* holder_;
   int number_;
   bool cacheable_;
   PropertyDetails details_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_PROPERTY_H_