void InterpreterMacroAssembler::check_and_handle_earlyret(Register scratch_reg) {

  {- -------------------------------------------
  (1) (JvmtiExport::can_force_early_return() が true でない場合は, (何もする必要が無いので) 以降の処理は全て省略)
      ---------------------------------------- -}

      if (JvmtiExport::can_force_early_return()) {

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

        Label L;

  {- -------------------------------------------
  (1) コード生成:
      「もし カレントスレッドが JvmtiThreadState を持っており (= JavaThread::jvmti_thread_state() が NULL ではなく),
        かつその JvmtiThreadState::_earlyret_state フィールドの値が JvmtiThreadState::earlyret_pending であれば,
        Interpreter::remove_activation_early_entry() が返すアドレスにジャンプする.」
      ---------------------------------------- -}

        Register thr_state = G3_scratch;
        ld_ptr(G2_thread, JavaThread::jvmti_thread_state_offset(), thr_state);
        tst(thr_state);
        br(zero, false, pt, L); // if (thread->jvmti_thread_state() == NULL) exit;
        delayed()->nop();

        // Initiate earlyret handling only if it is not already being processed.
        // If the flag has the earlyret_processing bit set, it means that this code
        // is called *during* earlyret handling - we don't want to reenter.
        ld(thr_state, JvmtiThreadState::earlyret_state_offset(), G4_scratch);
        cmp(G4_scratch, JvmtiThreadState::earlyret_pending);
        br(Assembler::notEqual, false, pt, L);
        delayed()->nop();

        // Call Interpreter::remove_activation_early_entry() to get the address of the
        // same-named entrypoint in the generated interpreter code
        ld(thr_state, JvmtiThreadState::earlyret_tos_offset(), Otos_l1);
        call_VM_leaf(noreg, CAST_FROM_FN_PTR(address, Interpreter::remove_activation_early_entry), Otos_l1);

        // Jump to Interpreter::_remove_activation_early_entry
        jmpl(O0, G0, G0);
        delayed()->nop();
        bind(L);
      }
    }