// Given that a new (potential) event has come in,
// maintain the current JVMTI location on a per-thread per-env basis
// and use it to filter out duplicate events:
// - instruction rewrites
// - breakpoint followed by single step
// - single step at a breakpoint

void JvmtiEnvThreadState::compare_and_set_current_location(methodOop new_method,
                                                           address new_location, jvmtiEvent event) {

      int new_bci = new_location - new_method->code_base();

      // The method is identified and stored as a jmethodID which is safe in this
      // case because the class cannot be unloaded while a method is executing.
      jmethodID new_method_id = new_method->jmethod_id();

      // the last breakpoint or single step was at this same location
      if (_current_bci == new_bci && _current_method_id == new_method_id) {
        switch (event) {
        case JVMTI_EVENT_BREAKPOINT:
          // Repeat breakpoint is complicated. If we previously posted a breakpoint
          // event at this location and if we also single stepped at this location
          // then we skip the duplicate breakpoint.
          _breakpoint_posted = _breakpoint_posted && _single_stepping_posted;
          break;
        case JVMTI_EVENT_SINGLE_STEP:
          // Repeat single step is easy: just don't post it again.
          // If step is pending for popframe then it may not be
          // a repeat step. The new_bci and method_id is same as current_bci
          // and current method_id after pop and step for recursive calls.
          // This has been handled by clearing the location
          _single_stepping_posted = true;
          break;
        default:
          assert(false, "invalid event value passed");
          break;
        }
        return;
      }

      set_current_location(new_method_id, new_bci);
      _breakpoint_posted = false;
      _single_stepping_posted = false;
    }