Issue 96362
Summary [compiler-rt] Clarify support for windows
Labels new issue
Assignees
Reporter h-vetinari
    In https://github.com/llvm/llvm-project/commit/0318ce8552896df7b180ee5481463eada65c755e, @AaronBallman added the following to the [C status page](https://clang.llvm.org/c_status.html) for support of `<complex.h>`:
> `_Complex` support requires an underlying support library such as compiler-rt to provide functions like `__divsc3`, but compiler-rt is not supported on Windows.

The following discussion ensued in the corresponding [PR](https://github.com/llvm/llvm-project/pull/88161):
> > @h-vetinari: I'm surprised about the "compiler-rt is not supported on windows" comment - in our distribution, we've been building compiler-rt on windows for years, and I don't remember significant issues.
> > 
> > It's true that `__divsc3` is not available _without_ compiler-rt (i.e. just relying on the msvc runtime libraries), but together with compiler-rt these things are generally possible? Note that a similar [situation](https://github.com/llvm/llvm-project/issues/54596) exists on `osx-arm` for example - in certain situations, linking `compiler-rt` is unavoidable.
>
> @AaronBallman: CC @petrhosek as compiler-rt CRT code owner -- is compiler-rt officially supported for Windows? The official documentation does not mention it under platform support: https://compiler-rt.llvm.org/

That statement of lack of support was now reiterated in https://github.com/llvm/llvm-project/commit/918ef312d1fda56ff783f3974b5a193542e5497c, and so I thought I'd open this issue to discuss.

In [conda-forge](https://conda-forge.org), we've been building and shipping compiler-rt since LLVM 9.0, and I'm not aware of fundamental issues that render the runtime unusable. To the contrary, it's been a [required](https://github.com/conda-forge/flang-feedstock/blob/main/recipe/meta.yaml#L54-57) component to get our flang-support for windows off the ground (which itself was a very [long story](https://labs.quansight.org/blog/building-scipy-with-flang)).

As such, I'd very much like for compiler-rt to stay _at least as usable_ as it has been over the last 5 years, even if perhaps the support may not be on par with other platforms. Better still would be explicit support of course. :)
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs

Reply via email to