C++ MonitorInfo::eliminated方法代码示例

void javaVFrame::print() {
  ResourceMark rm;
  vframe::print();
  tty->print("\t");
  method()->print_value();
  tty->cr();
  tty->print_cr("\tbci:    %d", bci());

  print_stack_values("locals",      locals());
  print_stack_values("expressions", expressions());

  GrowableArray<MonitorInfo*>* list = monitors();
  if (list->is_empty()) return;
  tty->print_cr("\tmonitor list:");
  for (int index = (list->length()-1); index >= 0; index--) {
    MonitorInfo* monitor = list->at(index);
    tty->print("\t  obj\t");
    if (monitor->owner_is_scalar_replaced()) {
      Klass* k = java_lang_Class::as_Klass(monitor->owner_klass());
      tty->print("( is scalar replaced %s)", k->external_name());
    } else if (monitor->owner() == NULL) {
      tty->print("( null )");
    } else {
      monitor->owner()->print_value();
      tty->print("(" INTPTR_FORMAT ")", (address)monitor->owner());
    }
    if (monitor->eliminated() && is_compiled_frame())
      tty->print(" ( lock is eliminated )");
    tty->cr();
    tty->print("\t  ");
    monitor->lock()->print_on(tty);
    tty->cr();
  }
}

GrowableArray<MonitorInfo*>* javaVFrame::locked_monitors() {
  assert(SafepointSynchronize::is_at_safepoint() || JavaThread::current() == thread(),
         "must be at safepoint or it's a java frame of the current thread");

  GrowableArray<MonitorInfo*>* mons = monitors();
  GrowableArray<MonitorInfo*>* result = new GrowableArray<MonitorInfo*>(mons->length());
  if (mons->is_empty()) return result;

  bool found_first_monitor = false;
  ObjectMonitor *pending_monitor = thread()->current_pending_monitor();
  ObjectMonitor *waiting_monitor = thread()->current_waiting_monitor();
  oop pending_obj = (pending_monitor != NULL ? (oop) pending_monitor->object() : (oop) NULL);
  oop waiting_obj = (waiting_monitor != NULL ? (oop) waiting_monitor->object() : (oop) NULL);

  for (int index = (mons->length()-1); index >= 0; index--) {
    MonitorInfo* monitor = mons->at(index);
    if (monitor->eliminated() && is_compiled_frame()) continue; // skip eliminated monitor
    oop obj = monitor->owner();
    if (obj == NULL) continue; // skip unowned monitor
    //
    // Skip the monitor that the thread is blocked to enter or waiting on
    //
    if (!found_first_monitor && (obj == pending_obj || obj == waiting_obj)) {
      continue;
    }
    found_first_monitor = true;
    result->append(monitor);
  }
  return result;
}

void javaVFrame::print_lock_info_on(outputStream* st, int frame_count) {
  ResourceMark rm;

  // If this is the first frame, and java.lang.Object.wait(...) then print out the receiver.
  if (frame_count == 0) {
    if (method()->name() == vmSymbols::wait_name() &&
        method()->method_holder()->name() == vmSymbols::java_lang_Object()) {
      StackValueCollection* locs = locals();
      if (!locs->is_empty()) {
        StackValue* sv = locs->at(0);
        if (sv->type() == T_OBJECT) {
          Handle o = locs->at(0)->get_obj();
          print_locked_object_class_name(st, o, "waiting on");
        }
      }
    } else if (thread()->current_park_blocker() != NULL) {
      oop obj = thread()->current_park_blocker();
      Klass* k = obj->klass();
      st->print_cr("\t- %s <" INTPTR_FORMAT "> (a %s)", "parking to wait for ", (address)obj, k->external_name());
    }
  }


  // Print out all monitors that we have locked or are trying to lock
  GrowableArray<MonitorInfo*>* mons = monitors();
  if (!mons->is_empty()) {
    bool found_first_monitor = false;
    for (int index = (mons->length()-1); index >= 0; index--) {
      MonitorInfo* monitor = mons->at(index);
      if (monitor->eliminated() && is_compiled_frame()) { // Eliminated in compiled code
        if (monitor->owner_is_scalar_replaced()) {
          Klass* k = java_lang_Class::as_Klass(monitor->owner_klass());
          st->print("\t- eliminated <owner is scalar replaced> (a %s)", k->external_name());
        } else {
          oop obj = monitor->owner();
          if (obj != NULL) {
            print_locked_object_class_name(st, obj, "eliminated");
          }
        }
        continue;
      }
      if (monitor->owner() != NULL) {

        // First, assume we have the monitor locked. If we haven't found an
        // owned monitor before and this is the first frame, then we need to
        // see if we have completed the lock or we are blocked trying to
        // acquire it - we can only be blocked if the monitor is inflated

        const char *lock_state = "locked"; // assume we have the monitor locked
        if (!found_first_monitor && frame_count == 0) {
          markOop mark = monitor->owner()->mark();
          if (mark->has_monitor() &&
              mark->monitor() == thread()->current_pending_monitor()) {
            lock_state = "waiting to lock";
          }
        }

        found_first_monitor = true;
        print_locked_object_class_name(st, monitor->owner(), lock_state);
      }
    }
  }
}