From: Nick Desaulniers <ndesaulniers@google.com>
To: Nathan Chancellor <natechancellor@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Stephen Boyd <swboyd@chromium.org>,
"# 3.4.x" <stable@vger.kernel.org>,
Michal Marek <michal.lkml@markovi.net>,
clang-built-linux <clang-built-linux@googlegroups.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] kbuild: initialize CLANG_FLAGS correctly in the top Makefile
Date: Mon, 29 Jul 2019 09:21:33 -0700 [thread overview]
Message-ID: <CAKwvOdnU8tLQ=wYAKs9Fy+3c2e_NmKL6H4kRKsRxH=sv16+8cQ@mail.gmail.com> (raw)
In-Reply-To: <20190729160412.GA100132@archlinux-threadripper>
On Mon, Jul 29, 2019 at 9:04 AM Nathan Chancellor
<natechancellor@gmail.com> wrote:
>
> On Mon, Jul 29, 2019 at 06:15:17PM +0900, Masahiro Yamada wrote:
> > CLANG_FLAGS is initialized by the following line:
> >
> > CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE:%-=%))
> >
> > ..., which is run only when CROSS_COMPILE is set.
> >
> > Some build targets (bindeb-pkg etc.) recurse to the top Makefile.
> >
> > When you build the kernel with Clang but without CROSS_COMPILE,
> > the same compiler flags such as -no-integrated-as are accumulated
> > into CLANG_FLAGS.
> >
> > If you run 'make CC=clang' and then 'make CC=clang bindeb-pkg',
> > Kbuild will recompile everything needlessly due to the build command
> > change.
> >
> > Fix this by correctly initializing CLANG_FLAGS.
> >
> > Fixes: 238bcbc4e07f ("kbuild: consolidate Clang compiler flags")
> > Cc: <stable@vger.kernel.org> # v4.20+
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>
> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
--
Thanks,
~Nick Desaulniers
next prev parent reply other threads:[~2019-07-29 16:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 9:15 [PATCH] kbuild: initialize CLANG_FLAGS correctly in the top Makefile Masahiro Yamada
2019-07-29 9:38 ` Masahiro Yamada
2019-07-29 16:04 ` Nathan Chancellor
2019-07-29 16:21 ` Nick Desaulniers [this message]
2019-07-30 16:45 ` Masahiro Yamada
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