cross-reference tool wanted

[news.crd.ge.com!e7sa!groleau@uunet.uu.net]

I have inherited some Ada code (lots) and need some tools to help understand it
What I am mainly looking for is a "free" or "cheap" cross-referencing tool.  I
have used AdaDL, and it would be acceptable, but we dropped its license and did
not replace it.  The quality of AdaDL would be the bare minimum, although I
don't need all its features.  Basically, I just need to be able to get from an
identifier to its declaration, from a subprogram spec to all its calls, etc.
(Even if visibility is through "use")

Another unfortunate detail is that I can't accept free-ware in compiled form--
I have to be able to persuade the "powers-that-be" that I have examined source
to ensure it contains no "malicious logic".

Please e-mail if you can help OR if you also want to know.  If there are enough
of the latter, I'll post a summary.

Thanks,

Wes Groleau