[libcxx-commits] [PATCH] D97572: [libc++] Include <__config_site> from <__config>

[Bjorn Pettersson via Phabricator via libcxx-commits]

bjope added a comment.

In D97572#2795853 <https://reviews.llvm.org/D97572#2795853>, @bjope wrote:

> I added some questions related to this in D103386 <https://reviews.llvm.org/D103386> (as I started to see failures with not finding `__config_site`after that patch, but I guess it is related to this patch).
>
> We been using `-DCLANG_DEFAULT_RTLIB=compiler-rt -DCLANG_DEFAULT_CXX_STDLIB=libc++` when building clang. And we also use `-DLLVM_ENABLE_PER_TARGET_RUNTIME_DIR=ON`.
> We also build clang/llc for all targets, but we only build libcxx for a subset of targets (e.g. x86_64-unknown-linux-gnu).
>
> When I only build libcxx for x86_64-unknown-linux-gnu, I only get a __config_site file for that specific triple inside bin/../include/x86_64-unknown-linux-gnu/c++/v1/__config_site in the build result.
> But then when compiling for a target such as powerpc64le-unknown-linux-gnu (the test case added in D103386 <https://reviews.llvm.org/D103386>), when including bin/../include/c++/v1/stddef.h, that wants wants to include <__config_site>, I run into trouble because there is no such header for the powerpc64le-unknown-linux-gnu triple.
>
> Is this kind of setup totally stupid and unsupported?
> (I kind of understand that using libcxx for powerpc64le-unknown-linux-gnu when not building libcxx for that target kind of is like begging for problems, but I doubt the test case should depend on that, or if I override CLANG_DEFAULT_CXX_STDLIB)
>
> Another problem is that a user was using my clang build together with "--target=x86_64-wrs-linux". This has worked fine in the past, but now when we only get "include/x86_64-unknown-linux-gnu/c++/v1/__config_site" in the compiler-clang install the user get failures about not finding `__config_site`. I could mention that this user is not even interested in linking the program, just using clang for static analysis. But the conclusion is that even for doing static analysis one need to match the target with one of the targets for which we have built libcxx.
> Maybe this is as expected? Or maybe it has been forseen?
>
> Should there perhaps always be some kind of generic `__config_site` that is used if there is not target override?

I still have these questions. Is there anyone that could help clarifying this a bit, how is it supposed to work?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D97572/new/

https://reviews.llvm.org/D97572