How to return whole body of the procedure

I’d like to solve some problem regarding C/C++ project. I have several files with C/C++ sources and I’d like to find some procedures in those files giving some rules. Those rules consists of regular expression. For example I’d like to find some procedure which name can be find by regular expression and extract whole body of this procedure to stdout or file. I’d like to run this as command line tool.

I’m wondering if it is possible with some tool from LLVM to do it?