void instanceRefKlass::acquire_pending_list_lock(BasicLock *pending_list_basic_lock) {

  {- -------------------------------------------
  (1) (変数宣言など) (See: PreserveExceptionMark)
      ---------------------------------------- -}

      // we may enter this with pending exception set
      PRESERVE_EXCEPTION_MARK;  // exceptions are never thrown, needed for TRAPS argument

  {- -------------------------------------------
  (1) java_lang_ref_Reference::pending_list_lock() に対して 
      ObjectSynchronizer::fast_enter() でロックを取得する.
      ---------------------------------------- -}

      Handle h_lock(THREAD, java_lang_ref_Reference::pending_list_lock());
      ObjectSynchronizer::fast_enter(h_lock, pending_list_basic_lock, false, THREAD);

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

      assert(ObjectSynchronizer::current_thread_holds_lock(
               JavaThread::current(), h_lock),
             "Locking should have succeeded");

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

      if (HAS_PENDING_EXCEPTION) CLEAR_PENDING_EXCEPTION;
    }