Having tried writing plugins for both, I very much prefer GCC's codebase. You have to adapt to its quirks, but at least it won't pull the rug from under your fe

Having tried writing plugins for both, I very much prefer GCC's codebase. You have to adapt to its quirks, but at least it won't pull the rug from under your feet gratuitously. There's a reason every major project ends up embedding a years-old copy of LLVM rather than just using the system version. If you're ignoring the API and writing IR directly there are advantages to LLVM though.