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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Wed, 2 Mar 2022 11:18:07 -0800
Message-ID: <CAKwvOdmouBTe5pH3JoP6EEfwNT5=6WvX3oCEZRxO0Dkf38S14w@mail.gmail.com>
Subject: Re: [PATCH v2 01/39] kbuild: Fix clang build
To:     Nathan Chancellor <nathan@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, keescook@chromium.org
Cc:     x86@kernel.org, joao@overdrivepizza.com, hjl.tools@gmail.com,
        jpoimboe@redhat.com, andrew.cooper3@citrix.com,
        linux-kernel@vger.kernel.org, samitolvanen@google.com,
        mark.rutland@arm.com, alyssa.milburn@intel.com, mbenes@suse.cz,
        rostedt@goodmis.org, mhiramat@kernel.org,
        alexei.starovoitov@gmail.com,
        Masahiro Yamada <masahiroy@kernel.org>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        llvm@lists.linux.dev
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On Wed, Mar 2, 2022 at 8:37 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Tue, Mar 01, 2022 at 01:16:04PM -0800, Nick Desaulniers wrote:
> > As per our previous discussion
> > https://lore.kernel.org/linux-kbuild/CAKwvOd=x9E=7WcCiieso-CDiiU-wMFcXL4W3V5j8dq7BL5QT+w@mail.gmail.com/
> > I'm still of the opionion that this should be solved by modifications
> > (permanent or one off) to one's $PATH.
>
> However, I think we could still address Peter's complaint of "there
> should be an easier way for me to use the tools that are already in my
> PATH" with his first iteration of this patch [1], which I feel is
> totally reasonable:
>
> $ make LLVM=-14
>
> It is still easy to use (in fact, it is shorter than 'CC=clang-14') and
> it does not change anything else about how we build with LLVM. We would
> just have to add something along the lines of
>
> "If your LLVM tools have a suffix like Debian's (clang-14, ld.lld-14,
> etc.), use LLVM=<suffix>.

"If your LLVM tools have a suffix and you prefer to test an explicit
version rather than the unsuffixed executables ..."

>
> $ make LLVM=-14"
>
> to Documentation/kbuild/llvm.rst.
>
> I might change the patch not to be so clever though:
>
> ifneq ($(LLVM),)
> ifneq ($(LLVM),1)
> LLVM_SFX := $(LLVM)
> endif
> endif
>
> [1]: https://lore.kernel.org/r/YXqpFHeY26sEbort@hirez.programming.kicks-ass.net/

I'd be much more amenable to that approach.
-- 
Thanks,
~Nick Desaulniers