static final Map<Class, _MethodCache> callOpt_cache = newDangerousWeakHashMap();

static O callOpt_cached(O o, S methodName, O... args) ctex {

  if (o == null) null;

  if (o instanceof Class) {

    Class c = (Class) o;

    _MethodCache cache = callOpt_getCache(c);

    // TODO: (super-rare) case where method exists static and non-static

    // with different args

    Method me = cache.findMethod(methodName, args);

    if (me == null || (me.getModifiers() & Modifier.STATIC) == 0) null;

    ret invokeMethod(me, null, args);

  } else {

    Class c = o.getClass();

    _MethodCache cache = callOpt_getCache(c);

    Method me = cache.findMethod(methodName, args);

    if (me == null) null;

    ret invokeMethod(me, o, args);

  }

}

// no longer synchronizes! (see #1102990)

static _MethodCache callOpt_getCache(Class c) {

  _MethodCache cache = callOpt_cache.get(c);

  if (cache == null)

    callOpt_cache.put(c, cache = _MethodCache(c));

  ret cache;

}