Make state stack thread local. When using Lockers the state stacks of...

src/vm-state.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 10 matching lines @@
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #ifndef V8_VM_STATE_H_
 #define V8_VM_STATE_H_
 
+#include "top.h"
+
 namespace v8 {
 namespace internal {
 
 class VMState BASE_EMBEDDED {
 #ifdef ENABLE_VMSTATE_TRACKING
  public:
   inline VMState(StateTag state);
   inline ~VMState();
 
   StateTag state() { return state_; }
   void set_external_callback(Address external_callback) {
     external_callback_ = external_callback;
   }
 
   // Used for debug asserts.
   static bool is_outermost_external() {
-    return current_state_ == 0;
+    return Top::current_vm_state() == 0;
   }
 
   static StateTag current_state() {
-    VMState* state = reinterpret_cast<VMState*>(current_state_);
+    VMState* state = Top::current_vm_state();
     return state ? state->state() : EXTERNAL;
   }
 
   static Address external_callback() {
-    VMState* state = reinterpret_cast<VMState*>(current_state_);
+    VMState* state = Top::current_vm_state();
     return state ? state->external_callback_ : NULL;
   }
 
  private:
   bool disabled_;
   StateTag state_;
   VMState* previous_;
   Address external_callback_;
 
-  // A stack of VM states.
-  static AtomicWord current_state_;
 #else
  public:
   explicit VMState(StateTag state) {}
 #endif
 };
 
 } }  // namespace v8::internal
 
 
 #endif  // V8_VM_STATE_H_