[llvm] [ORC-RT] Initial check-in for a new, top-level ORC runtime project. (PR #113499)

[Lang Hames via llvm-commits]

lhames wrote:

@llvm-beanz

> I always felt that it was probably better to have darwin build thin-libraries and even put them in separate directories structured the way the Linux toolchain does. That would allow simplifying a lot of logic in the darwin driver too. Since the driver always generates single-architecture compile and link commands and uses lipo to merge objects when building fat binaries, there is no reason that fat archives are strictly needed.

I discussed this with my group and we agreed that we'd like the ORC runtime to build as you've suggested. There were no objections to moving more Apple projects in this direction, but I didn't canvas opinions more widely inside Apple. ;)

Do you think it'd be reasonable / possible to add some CMake allow a linux-style ORC runtime to coexist with an Apple legacy-style build of compiler-rt (which seems to be a prerequisite for a multiconfig build)? At the very least it seems like that'll require isolating compiler-rt from `LLVM_RUNTIME_TARGETS` when the ORC runtime is being built.

https://github.com/llvm/llvm-project/pull/113499