[anarazel]

> Can anyone think of any reasonably common stacks using LLVM as a JIT?

We just added LLVM based JIT to PostgreSQL. Don't think we have quite the same issues as JITing generic interpreted languages though, because the planner gives us much more information about the likely cost of executing a query. So the need for a super-fast baseline JIT isn't as big.

> But that doesn't mean you can't use a conventional compiler stack like LLVM as a JIT and get excellent code - it' just going to take its own sweet time doing so.

I think that's partially due to people using the expensive default pipeline when using optimization. A lot of those either don't make sense for the source language, or not for the first JIT foreground JIT pass.

The biggest issue I have with LLVM wrt around JITing is that it's error handling isn't really good enough. It's fine to just fatal error if you're in a AOT compiler world, but that's much less acceptable inside a database. There's moves to make at least parts of LLVM exception safe, but ...