void VM_ThreadStop::doit() {

  {- -------------------------------------------
  (1) (assert)
      ---------------------------------------- -}

      assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");

  {- -------------------------------------------
  (1) JavaThread::send_thread_stop() を呼んで, 
      処理対象のスレッド内で例外を発生させる.

      (なお, 処理対象のスレッドが見つからない(= まだ開始していない or 既に死んでいる)場合には, 何もしない)
      ---------------------------------------- -}

      JavaThread* target = java_lang_Thread::thread(target_thread());
      // Note that this now allows multiple ThreadDeath exceptions to be
      // thrown at a thread.
      if (target != NULL) {
        // the thread has run and is not already in the process of exiting
        target->send_thread_stop(throwable());
      }
    }