Re: [PATCH v2 0/2] sparc/build: Rework CFLAGS for clang compatibility

[Nathan Chancellor]

On Wed, Oct 23, 2024 at 12:38:59PM +0900, Masahiro Yamada wrote:
> On Wed, Oct 23, 2024 at 9:44 AM Koakuma <koachan@xxxxxxxxxxxxxx> wrote:
> > I'm not sure if I should update the documentation now given that LLVM support
> > is nowhere near as complete as other architectures, but I'll do it if needed...
> 
> Nathan said he was able to build the kernel.
> 
> If so, I think this should be documented (required LLVM version and
> the supported build command),
> otherwise people cannot test this patch.

I am not sure that there is a super concise way to describe for
Documentation/kbuild/llvm.rst that sparc currently requires 'CC=clang
LLVM_IAS=0' along with a build of clang from the main branch of
llvm-project to work properly. I worry that adding any sort of mention
of sparc in there will have people flooding to try older versions of
clang like you did or LLVM=1 when there are obviously known issues that
the upstream LLVM folks have not had a chance to tackle (but maybe it
will be good to get issues on file for those).

If it would be useful, I could send a separate email documenting exactly
what was tested and how it was tested as a reference in the face of
future changes, until better support for the LLVM tools is enacted.

Cheers,
Nathan