From: Nathan Chancellor <natechancellor@gmail.com>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: linux-kbuild@vger.kernel.org, Stephen Boyd <swboyd@chromium.org>,
Nick Desaulniers <ndesaulniers@google.com>,
stable@vger.kernel.org, Michal Marek <michal.lkml@markovi.net>,
clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kbuild: initialize CLANG_FLAGS correctly in the top Makefile
Date: Mon, 29 Jul 2019 09:04:12 -0700 [thread overview]
Message-ID: <20190729160412.GA100132@archlinux-threadripper> (raw)
In-Reply-To: <20190729091517.5334-1-yamada.masahiro@socionext.com>
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>
next prev parent reply other threads:[~2019-07-29 16:04 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 [this message]
2019-07-29 16:21 ` Nick Desaulniers
2019-07-30 16:45 ` Masahiro Yamada
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