PHP extension: How to get current object of a function

I am creating an PHP extension to find the call stack of PHP application. This is PHP 5.6.

Zend API callback "_zend_execute_ex" and get_active_function_name(TSRMLS_C) can able to get the function names, But I needs to get PHP class object,to identify which function from which class is executed in my extension. How can i achieve this?