d8: Fix some TSAN bugs

src/d8.h

 // 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.
 
 #ifndef V8_D8_H_
 #define V8_D8_H_
 
 #ifndef V8_SHARED
 #include "src/allocation.h"
 #include "src/hashmap.h"
@@ skipping 221 matching lines @@
   i::List<SerializationData*> data_;
 };
 
 
 class Worker {
  public:
   Worker();
   ~Worker();
 
   void StartExecuteInThread(Isolate* isolate, const char* script);
+  // Post a message to the worker's incoming message queue. The worker will
+  // take ownership of the SerializationData.
   void PostMessage(SerializationData* data);
+  // Synchronously retrieve messages from the worker's outgoing message queue.
+  // If there is no message in the queue, block until a message is available.
+  // If there are no messages in the queue and the worker is no longer running,
+  // return nullptr.
   SerializationData* GetMessage();
+  // Terminate the worker's event loop. Messages from the worker that have been
+  // queued can still be read via GetMessage().
   void Terminate();
+  // Terminate and join the thread.
+  void WaitForThread();
 
  private:
   class WorkerThread : public base::Thread {
    public:
     explicit WorkerThread(Worker* worker)
         : base::Thread(base::Thread::Options("WorkerThread")),
           worker_(worker) {}
 
     virtual void Run() { worker_->ExecuteInThread(); }
 
    private:
     Worker* worker_;
   };
 
-  enum State { IDLE, RUNNING, TERMINATED };
+  enum State {
+    IDLE,       // The worker thread hasn't been started yet
+    RUNNING,    // The worker thread is running and hasn't been terminated
+    TERMINATED  // The worker thread has been terminated and will soon finish
+  };
 
   void ExecuteInThread();
   void Cleanup();
   static void PostMessageOut(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   base::Semaphore in_semaphore_;
   base::Semaphore out_semaphore_;
   SerializationDataQueue in_queue_;
   SerializationDataQueue out_queue_;
   base::Thread* thread_;
   char* script_;
   base::Atomic32 state_;
+  base::Atomic32 join_called_;
 };
 #endif  // !V8_SHARED
 
 
 class ShellOptions {
  public:
   ShellOptions()
       : script_executed(false),
         last_run(true),
         send_idle_notification(false),
@@ skipping 195 matching lines @@
   static void RunShell(Isolate* isolate);
   static bool SetOptions(int argc, char* argv[]);
   static Handle<ObjectTemplate> CreateGlobalTemplate(Isolate* isolate);
 };
 
 
 }  // namespace v8
 
 
 #endif  // V8_D8_H_