哪种技术最适合性能和内存？

Question

我必须从其他几个类中访问一个类。我想知道是否更好地使用全球＆＃39;或者将课程传授给其他班级。

$m_class = new SOmeClass();



#1 -
class AnotherClass{

   private $mClass;
   function __construct(){

      global $m_class;
      $this->mClass = $m_class;
   }
}

#2
class AnotherClass{

     private $mClass;
     function __construct($mClassPassed){

          $this->mClass = $mClassPassed;
     }


}