Re: [PATCH] compiler-clang: add build check for clang 10.0.1

From: Nick Desaulniers
Date: Mon Aug 31 2020 - 19:32:19 EST


On Wed, Aug 26, 2020 at 2:42 PM Nathan Chancellor
<natechancellor@xxxxxxxxx> wrote:
>
> On Wed, Aug 26, 2020 at 01:14:19PM -0700, Nick Desaulniers wrote:
> > During Plumbers 2020, we voted to just support the latest release of
> > Clang for now. Add a compile time check for this.
> >
> > Older clang's may work, but we will likely drop workarounds for older
> > versions.
>
> I think this part of the commit message is a little wishy-washy. If we

Yep, you're right. I'm still in denial. Let me rip that bandaid off
and send a v2, with your and Kees' suggestions.

Sorry, the docs patch already got picked up. Let's follow up with
additional patches to docs separately.

> are breaking the build for clang < 10.0.1, we are not saying "may work",
> we are saying "won't work". Because of this, we should take the
> opportunity to clean up behind us and revert/remove parts of:
>
> 87e0d4f0f37f ("kbuild: disable clang's default use of -fmerge-all-constants")
> b0fe66cf0950 ("ARM: 8905/1: Emit __gnu_mcount_nc when using Clang 10.0.0 or newer")
> b9249cba25a5 ("arm64: bti: Require clang >= 10.0.1 for in-kernel BTI support")
> 3acf4be23528 ("arm64: vdso: Fix compilation with clang older than 8")

I'd prefer to see this land in mainline first; otherwise, I'm worried
about this patch "racing" to mainline with those patches if they go
via separate trees. Thoughts?
--
Thanks,
~Nick Desaulniers