How to extract functions from PHP source code with its usage in PHP

I am looking for some library or class in PHP or Linux to extract all functions/methods from PHP source code along with its usage in project files.

I have used PHP ReflectionMethod and ReflectionClass but these libraries will return basic details without its usage details.

Example for ReflectionMethod:

    $classString = (string)$classNode->namespacedName;
    $de = new \ReflectionMethod($classString, 'testAction');
    echo $de->getName() . ' - ' . $de->getStartLine();

I do not see any method which can return its usage from files or a complete directory.

Please let me know if you need any other details.