void JvmtiEnvThreadState::reset_current_location(jvmtiEvent event_type, bool enabled) {

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

      assert(event_type == JVMTI_EVENT_SINGLE_STEP || event_type == JVMTI_EVENT_BREAKPOINT,
             "must be single-step or breakpoint event");

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

      // Current location is used to detect the following:
      // 1) a breakpoint event followed by single-stepping to the same bci
      // 2) single-step to a bytecode that will be transformed to a fast version
      // We skip to avoid posting the duplicate single-stepping event.

      // If single-stepping is disabled, clear current location so that
      // single-stepping to the same method and bcp at a later time will be
      // detected if single-stepping is enabled at that time (see 4388912).

      // If single-stepping is enabled, set the current location to the
      // current method and bcp. This covers the following type of case,
      // e.g., the debugger stepi command:
      // - bytecode single stepped
      // - SINGLE_STEP event posted and SINGLE_STEP event disabled
      // - SINGLE_STEP event reenabled
      // - bytecode rewritten to fast version

      // If breakpoint event is disabled, clear current location only if
      // single-stepping is not enabled.  Otherwise, keep the thread location
      // to detect any duplicate events.

      if (enabled) {
        // If enabling breakpoint, no need to reset.
        // Can't do anything if empty stack.
        if (event_type == JVMTI_EVENT_SINGLE_STEP && _thread->has_last_Java_frame()) {
          jmethodID method_id;
          int bci;
          // The java thread stack may not be walkable for a running thread
          // so get current location at safepoint.
          VM_GetCurrentLocation op(_thread);
          VMThread::execute(&op);
          op.get_current_location(&method_id, &bci);
          set_current_location(method_id, bci);
        }
      } else if (event_type == JVMTI_EVENT_SINGLE_STEP || !is_enabled(JVMTI_EVENT_SINGLE_STEP)) {
        // If this is to disable breakpoint, also check if single-step is not enabled
        clear_current_location();
      }
    }