[libcxx-dev] Introducing shared top-level CMake modules

[Petr Hosek via libcxx-dev]

I'm about to land D88458 <https://reviews.llvm.org/D88458> which is notable
because it extracts shared CMake logic that has been duplicated across
libc++, libc++abi, libunwind and compiler-rt and moves it to a shared
top-level CMake module.

We hope that this will reduce duplication and promote reuse in LLVM build,
but it also means that it'll not longer be possible to build projects
libc++, libc++abi, libunwind and compiler-rt using CMake without having the
full monorepo checkout (as opposed to just checking out slices) unless you
also check out the top-level CMake module directory.

We don't think this should introduce significant issues since requiring the
full monorepo checkout is something we've been already implicitly assuming
in various parts of our build, but I still want to call out this change in
case you see related issues, especially in downstream builds that aren't
covered by upstream bots.

We plan on following up with other changes in this direction (such as
D110005 <https://reviews.llvm.org/D110005>) which should in the long term
result in a simpler and faster CMake build.

Please let me know if you have any questions.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/libcxx-dev/attachments/20211007/e912372f/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/pkcs7-signature
Size: 3996 bytes
Desc: S/MIME Cryptographic Signature
URL: <http://lists.llvm.org/pipermail/libcxx-dev/attachments/20211007/e912372f/attachment.bin>