"cscope + ascope" is the best thing ever I found for groking the code(in emacs). It is great for getting your way around huge code base. I find myself using "ascope-find-this-symbol" all the time, which gives me all occurrences/usages of that symbol.
yeah without cscope it would be impossible to follow huge code bases. though i am not sure how good is cscope at generating symbol database for non-c languages.
ideally, it would be really nice if cscope/xcscope provided some means of creating (and saving) bunch of call-stacks, which you can navigate in forwards/reverse direction (not sure if i am making much sense here...)
I wrote this some time ago for navigating with (g|e)tags, allowing you to view the current stack as you drill down:
https://github.com/markhepburn/tags-view
(you can prune the stack too, so you only see the important bits of context)
It worked well for my own usage, but it probably needs some love. I'm not sure how *cscope works though, and if it would be possible to add it as another backend.
ascope is an improvement over xcscope that runs all queries through a single cscope process, instead of starting a new process and reloading the database for each query. It was made by Staton Sun as a merge between xscope and another single-process interface, bscope
