static inline void generate_satb_log_enqueue_if_necessary(bool with_frame) {

  {- -------------------------------------------
  (1) 既に satb_log_enqueue_with_frame (with_frame 引数が false の場合は satb_log_enqueue_frameless) が
      初期化済みであれば何もしない.

      まだ初期化されてなければ, generate_satb_log_enqueue() を呼んで初期化を行う.

      (なお, 初期化を行った場合はついでに(トレース出力)も出している)
      ---------------------------------------- -}

      if (with_frame) {
        if (satb_log_enqueue_with_frame == 0) {
          generate_satb_log_enqueue(with_frame);
          assert(satb_log_enqueue_with_frame != 0, "postcondition.");
          if (G1SATBPrintStubs) {
            tty->print_cr("Generated with-frame satb enqueue:");
            Disassembler::decode((u_char*)satb_log_enqueue_with_frame,
                                 satb_log_enqueue_with_frame_end,
                                 tty);
          }
        }
      } else {
        if (satb_log_enqueue_frameless == 0) {
          generate_satb_log_enqueue(with_frame);
          assert(satb_log_enqueue_frameless != 0, "postcondition.");
          if (G1SATBPrintStubs) {
            tty->print_cr("Generated frameless satb enqueue:");
            Disassembler::decode((u_char*)satb_log_enqueue_frameless,
                                 satb_log_enqueue_frameless_end,
                                 tty);
          }
        }
      }
    }