Triaging clang C++ frontend bugs - Shafik Yaghmour's Blog
I have been triaging clang C++ frontend bugs for about a couple of years now and I wanted to share some of the lessons I have learnt in the hopes that others in the C++/LLVM community can feel less intimidated and get in on the fun as well. I have tried to develop some good practices for triaging and I have attempted to distill those here as well.
The clang frontend usually gets several new bugs a day and it is important to our users to at least do and initial assessment of each bug in a timely manner. Bugs are going to fall into one of many categories (not exhaustive list):
If you are interested in helping out and have questions, the clang channel on the llvm Discord is probably the best place to ask for help.
Before I get into the heart of the matter, I will address some miscellaneous topics that are important to triaging in general.
Often a bug report will provide a Minimal Reproducer Example or otherwise known as a SSCCE via a godbolt link. For clang frontend bugs we also require no standard headers for reproducers (since after preprocessing standard headers will result in a large amount of code). Often they do not have a minimal reproducer: it might be a link to repository, a compressed set of code or a godbolt link to code that is not minimal in some way. Once we confirm it is actually a bug or we can’t make progress we usually require a minimal reproducer to make progress. Sometimes it is trivial to reduce by hand but usually not and it requires the use of tools such as creduce and cvise and we suggest using such in the LLVM tools for folks submitting bugs section.
