funNameBF = function(cx, fn) {
var i; for(i in cx ) {
   if ( cx[i] === fn ) {
      return i;
   }
}
return undefined;
}

AAA = {
fff: function() {  console.log( funNameBF(this, arguments.callee) )  }
}
>Object
AAA.fff()
>fff
>undefined