CompilerJobs – A listing of compiler, language and runtime teams
mgaudet.github.io
mgaudet.github.io
They keep an updated list regularly since the mid-90s.
Everyone starts somewhere. It's not the easiest thing, but I think can be done.
[1]: https://www.mgaudet.ca/technical/2019/12/10/compiler-jobs
With so many companies using LLVM or GCC there probably are a few where the job's output is mostly or all open source by default, and there are certainly other compiler jobs where it isn't.
Hard to judge often!
but what actually "LLVM" means here? proficency at LLVM IR and it's tools or internals and source code of LLVM?
What's the incentive for anyone to work there?
Some of the companies in this list are known to pay very well for compiler type senior roles (and don't advertise that fact), some of them probably don't.