There are several conferences and journals that will accept submissions from open-source developers (or anyone else). Many have a blind reviewing process, so the lack of a famous name/affiliation shouldn't have an effect. Classic compiler conferences are PLDI (programming language design and implementation) and CGO (code generation and optimization). And of course, the LLVM conferences seem a natural venue.
But generally it's hard to publish code. Mostly you have to write a paper, and the paper usually has to have an element of novelty. Can't just be "I built this compiler!"
Lot of LLVM talks seem to be tutorials, which is another approach, and of course very useful.
Or you can do like Adrian Sampson and many others, and publish it via a blog. You won't get tenure that way, but most people don't care.
FWIW, papers that focus on implementation are (slowly) becoming acceptable in the compilers community. However, like you mentioned, novelty is essential.
The arxiv is another possible option for implementation papers (if you don’t mind piggybacking on another CoRR category like architecture or programming languages).
But generally it's hard to publish code. Mostly you have to write a paper, and the paper usually has to have an element of novelty. Can't just be "I built this compiler!"
Lot of LLVM talks seem to be tutorials, which is another approach, and of course very useful.
Or you can do like Adrian Sampson and many others, and publish it via a blog. You won't get tenure that way, but most people don't care.