C++ extensions

I am attempting to parse a superset of C++ using clang. What I ultimately need is a CFG and some other information from the AST. I am assuming I'll need to add my extensions to the lexer and the parser and then extend the AST to add the new constructs (these mainly include some new struct types, special function calls mixed in with C++ code).

I'm going to look at the code base and play around with it a bit. I'll appreciate any pointers on "files of interest". thanks,