Fast TLS support.

src/isolate.h

 // Copyright 2010 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 384 matching lines @@
 
   // Returns the PerIsolateThreadData for the current thread (or NULL if one is
   // not currently set).
   static PerIsolateThreadData* CurrentPerIsolateThreadData() {
     return reinterpret_cast<PerIsolateThreadData*>(
         Thread::GetThreadLocal(per_isolate_thread_data_key_));
   }
 
   // Returns the isolate inside which the current thread is running.
   INLINE(static Isolate* Current()) {
-    Isolate* isolate = UncheckedCurrent();
+    Isolate* isolate = reinterpret_cast<Isolate*>(
+        Thread::GetExistingThreadLocal(isolate_key_));
     ASSERT(isolate != NULL);
     return isolate;
   }
 
   INLINE(static Isolate* UncheckedCurrent()) {
     return reinterpret_cast<Isolate*>(Thread::GetThreadLocal(isolate_key_));
   }
 
   bool Init(Deserializer* des);
 
@@ skipping 879 matching lines @@
 
 } }  // namespace v8::internal
 
 // TODO(isolates): Get rid of these -inl.h includes and place them only where
 //                 they're needed.
 #include "allocation-inl.h"
 #include "zone-inl.h"
 #include "frames-inl.h"
 
 #endif  // V8_ISOLATE_H_