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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Wed, 7 Sep 2022 13:14:10 +0900
Message-ID: <CAK7LNASBAMRwGPH1gyt5JeBTVX3UkmC4DGkbjSxrwWFO+4+yEg@mail.gmail.com>
Subject: Re: [PATCH v2 2/5] Makefile.compiler: Use KBUILD_AFLAGS for as-option
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        Michal Marek <michal.lkml@markovi.net>,
        Tom Rix <trix@redhat.com>,
        Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        clang-built-linux <llvm@lists.linux.dev>,
        X86 ML <x86@kernel.org>,
        Dmitrii Bundin <dmitrii.bundin.a@gmail.com>,
        Fangrui Song <maskray@google.com>,
        Alexey Alexandrov <aalexand@google.com>,
        Bill Wendling <morbo@google.com>,
        Greg Thelen <gthelen@google.com>
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On Wed, Sep 7, 2022 at 1:08 AM Nathan Chancellor <nathan@kernel.org> wrote:
>
> On Mon, Sep 05, 2022 at 06:09:28PM +0900, Masahiro Yamada wrote:
> > On Thu, Sep 1, 2022 at 4:53 AM Nathan Chancellor <nathan@kernel.org> wrote:
> > >
> > > On Wed, Aug 31, 2022 at 11:44:05AM -0700, Nick Desaulniers wrote:
> > > > as-instr uses KBUILD_AFLAGS, but as-option uses KBUILD_CFLAGS.  This can
> > > > cause as-option to fail unexpectedly because clang will emit
> > > > -Werror,-Wunused-command-line-argument for various -m and -f flags for
> > > > assembler sources.
> > >
> > > Now that I am looking closer at it, where does that '-Werror' come from?
> >
> > The related commit is
> > c3f0d0bc5b01ad90c45276952802455750444b4f
> >
> > The previous discussion with Arnd is
> > https://lore.kernel.org/linux-kbuild/20170314213724.3836900-1-arnd@arndb.de/
>
> Right, although this is for cc-option, not as-option, no?


Sorry, I misunderstood your comments.
My reference is about -Werror in cc-option. It is unrelated to as-option.


You are right.
Currently, as-option takes KBUILD_CFLAGS instead of KBUILD_AFLAGS.

The '-Werror,' of -Werror,-Wunused-command-line-argument
presumably came from CONFIG_WERROR.


-- 
Best Regards
Masahiro Yamada