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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 03 Apr 2018 21:58:03 +0000
Message-ID: <CAKwvOdkaBNTyNjackJcWYkdfwyR2wjAruMFqN8LuYqC8V0ii_A@mail.gmail.com>
Subject: Re: [GIT PULL] x86/build changes for v4.17
To:     Matthias Kaehlcke <mka@chromium.org>
Cc:     Ingo Molnar <mingo@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        James Y Knight <jyknight@google.com>,
        Chandler Carruth <chandlerc@google.com>,
        Stephen Hines <srhines@google.com>,
        Kees Cook <keescook@google.com>, groeck@chromium.org,
        Greg Hackmann <ghackmann@google.com>,
        Greg KH <gregkh@linuxfoundation.org>
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Speaking more with our internal LLVM teams, there ARE a few different
approaches to implementing asm-goto in LLVM proposed, by external parties
to Google.  These proposals haven't progressed to code review, so we've
asked our LLVM teams to reignite these discussions with increased priority,
if not implement the feature outright.  We (Google kernel AND llvm hackers)
are committed to supporting the Linux kernel being built with Clang.

I can see both sides where eventually a long-requested feature-request
should come to a head, especially with good evidence (
https://lkml.org/lkml/2018/2/14/895), but just as you wouldn't accept a
patch that doesn't compile with GCC, I'd like to request that we don't
merge patches that fail to compile with Clang (or at least start to think
what that might look like).  I realize that would increase the burden on
patch authors and maintainers, so I'm interested in better approaches or
ideas.

I've been in contact with the 0-day bot maintainers, kernel-ci maintainers,
and even run my own run down version of 0-day bot on my workstation
hourly.  I think those will help reduce the burden of testing patches with
multiple different compilers.
--
Thanks,
~Nick Desaulniers