speaking of hard, the DOE actually funds a project that has been around for 20+ years now (ROSE) that involves (among other things) doing static analysis on and automatically translating between C/C++/Cuda and even high level languages like Python as well as HPC variants of C/C++. They have a combined AST that supports all of those languages with the same set of node types essentially. Quite cool. I got to work on it when I was an intern at Livermore, summer of 2014.

and it's open source as well! http://rosecompiler.org/ROSE_HTML_Reference/index.html