void VMThread::evaluate_operation(VM_Operation* op) {

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      ResourceMark rm;

      {

  {- -------------------------------------------
  (1) (プロファイル情報の記録) ("sun.threads.vmOperationTime") (See: PerfTraceTime)
      ---------------------------------------- -}

        PerfTraceTime vm_op_timer(perf_accumulated_vm_operation_time());

  {- -------------------------------------------
  (1) (DTrace のフック点)
      ---------------------------------------- -}

        HS_DTRACE_PROBE3(hotspot, vmops__begin, op->name(), strlen(op->name()),
                         op->evaluation_mode());

  {- -------------------------------------------
  (1) VM_Operation::evaluate() を呼び出して VM_Operation を実行する.
      ---------------------------------------- -}

        op->evaluate();

  {- -------------------------------------------
  (1) (DTrace のフック点)
      ---------------------------------------- -}

        HS_DTRACE_PROBE3(hotspot, vmops__end, op->name(), strlen(op->name()),
                         op->evaluation_mode());
      }

  {- -------------------------------------------
  (1) (変数宣言など)
      ---------------------------------------- -}

      // Last access of info in _cur_vm_operation!
      bool c_heap_allocated = op->is_cheap_allocated();

  {- -------------------------------------------
  (1) VM_Operation の完了を待っている JavaThread がいる場合には(= VM_Operation::evaluate_concurrently() が false の場合には), 
      完了したことが分かるようにカウンタを増加させておく.
      (See: VMThread::execute())
      ---------------------------------------- -}

      // Mark as completed
      if (!op->evaluate_concurrently()) {
        op->calling_thread()->increment_vm_operation_completed_count();
      }
      // It is unsafe to access the _cur_vm_operation after the 'increment_vm_operation_completed_count' call,
      // since if it is stack allocated the calling thread might have deallocated

  {- -------------------------------------------
  (1) もし VM_Operation オブジェクトが C ヒープ上に確保されたものであれば delete しておく.
      ---------------------------------------- -}

      if (c_heap_allocated) {
        delete _cur_vm_operation;
      }
    }