With static analysis, you'll probably not get very far, and it certainly won't be reliable.
in reply to finding subroutine dependencies?
Runtime analysis like what some profilers Devel::NYTProf and code coverage tools Devel::Cover do may work better, provided you've got enough "test" routines to cover all the code paths.
It's possible to build what you want with runtime inspections. Searching cpan for Devel might turn up something more directly suitable, but I'm not aware of anything that does exactly what you want. Sepia::Xref seems close, though.