[libc-commits] [libc] [libc] Export the RPC interface from `libc` (PR #71432)

[Jon Chesterfield via libc-commits]

https://github.com/JonChesterfield requested changes to this pull request.

Left various comments inline.

I think exporting RPC from libc by wrapping the C++ in a layer of C is fundamentally the wrong thing to be doing and the signal to noise ratio of this patch somewhat supports that.

The RPC layer benefits from being in C++. We'd like it to be easily usable outside of libc, e.g. from the openmp runtime. The llvm libc is implemented in C++.

Instead of doing this force-through-C dance with the associated unsafety and complexity, and given that the libc project doesn't want to export C++ interfaces, we should move RPC to some other subproject. The new offload one seems an obvious fit. Then libc uses the C++ version directly from that subproject.

https://github.com/llvm/llvm-project/pull/71432