[PATCH] D138451: [lld/mac] Add support for distributed ThinLTO

Mon Jun 12 20:41:20 PDT 2023

glandium added a comment.

In D138451#4151685 <https://reviews.llvm.org/D138451#4151685>, @haowei wrote:

> With this patch, it will output: `ld64.lld: error: No available targets are compatible with triple ""`. Without this patch, the clang++ will return 0.
> Would you mind take a look please?
>
> We are still trying to understand why this patch is causing this issue, maybe it uncovered a bug somewhere else.

We're seeing the same with Firefox, and this comes from the AlwaysEmitRegularLTOObj change. The problem we have is that we use -object_path_lto to have a deterministic path that keeps the objects around for dsymutil (otherwise, being temporary files, they are removed, although I guess we could use -save-temps instead, but that would remove the determinism), and /some/ things we build end up not using LTO, so the LTO dir ends up empty for them, but with AlwaysEmitRegularLTOObj being true, the error is emitted. I guess there's a case to be made that maybe that error should not be emitted when the directory is empty because there was nothing to LTO.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D138451/new/

https://reviews.llvm.org/D138451