[libcxx-commits] [PATCH] D97379: [libcxxabi] Fewer assumptions about path from libcxx to libcxxabi

Louis Dionne via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Thu Feb 25 11:39:37 PST 2021

ldionne accepted this revision.
ldionne added a comment.
This revision is now accepted and ready to land.

I'm fine with this change per-se, however the problem I have is with Chrome swimming against the current in terms of having the runtimes in non-standard locations.

We introduced this requirement a year ago: https://lists.llvm.org/pipermail/libcxx-dev/2020-March/000714.html. There were even suggestions about merging libc++ and libc++abi, which is something I know Eric has been wanting to do for a long time.

We can make this change, but it would be best for Chrome to change the way it's currently ingesting libc++ and libc++abi to account for those requirements. By the way, I think we had an explicit error at the top of the CMake that would have fired for using libc++/libc++abi in non-standard locations relative to each other, but I removed it some time ago (apparently before you updated your version of the libs).

The bottom line is that we want to be able to assume that we are in a monorepo-like layout in libc++ and libc++abi because it simplifies things, and in the future we might very well depend on some things like a common set of CMake utilities outside of either `libcxx/` or `libcxxabi/`. If you change how you ingest libcxx/libcxxabi right now and ingest the monorepo instead (or at least a subset of the directories in the monorepo, right now only `libcxx/` and `libcxxabi/` are needed to build either), you won't risk being broken again in the future.



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