Find unused code and pages in PHP project


our website is running with a PHP based CMS which has become a little bit large. Our system is based on a common CMS-System, which we have changed a lot to meet our requitrements.
I am afraid, that over the years a lot of code, functions and .php-pages have become obsolete.

Is there a software to check for unused functions, variables, pages etc.?
A software that has a decent price for someone who will probably only use it a few times?


Ive been using:

They have a range of products that check your files for broken php code

Hope that’s helped!

So wicht tool would exactly find obsolete code and functions?