Starting work on a Pre-existing Project

Question

So this is more of a generic question. I seem to keep finding myself being put on larger and larger projects. Recently I have been assigned to a very large project written in C and VHDL. The goal is for me to become familiar with the code and eventually take the lead on the project. This is by far the largest project I have been assigned to work on that I didn't start.

So here is my question: What methods/tools do you use to learn how everything works?

Do you just increase and expand on comments?
Do you make a UML representation of the project?

Any tips would be great! Thanks

Answer 1

If you can, sit down with the folks who are currently working on it and ask for a high-level solution overview to start and then go on your own from there, digging into the pieces one by one. Identify who is responsible for each functional area and follow up with them when you hit a rough spot.

Try and embed yourself with the team as quickly as possible, ask to sit in on code reviews and such. This will get you ramped up pretty quickly.

Answer 2

I find the UML almost useless. I find much more useful, real, static and dynamic call graphs. After I generate the call graph, I usually grok the source code through OpenGrok and cscope. See what calls what and what is called by whom for the most hot methods.