Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Tue, 2 Mar 2021 14:02:52 -0800
From:   Fangrui Song <maskray@google.com>
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org,
        clang-built-linux@googlegroups.com
Subject: Re: [PATCH 2/2] Makefile: Only specify '--prefix=' when building
 with clang + GNU as
Message-ID: <20210302220252.ulvlsfyp4ordwrky@google.com>
References: <20210302210646.3044738-1-nathan@kernel.org>
 <20210302210646.3044738-2-nathan@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii; format=flowed
Content-Disposition: inline
In-Reply-To: <20210302210646.3044738-2-nathan@kernel.org>
Precedence: bulk

On 2021-03-02, Nathan Chancellor wrote:
>When building with LLVM_IAS=1, there is no point to specifying
>'--prefix=' because that flag is only used to find the cross assembler,
>which is clang itself when building with LLVM_IAS=1. All of the other
>tools are invoked directly from PATH or a full path specified via the
>command line, which does not depend on the value of '--prefix='.
>
>Sharing commands to reproduce issues becomes a little bit easier without
>a '--prefix=' value because that '--prefix=' value is specific to a
>user's machine due to it being an absolute path.
>
>Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Reviewed-by: Fangrui Song <maskray@google.com>

clang can spawn GNU as (if -f?no-integrated-as is specified) and GNU
objcopy (-f?no-integrated-as and -gsplit-dwarf and -g[123]).

With LLVM_IAS=1, these cases are ruled out.