Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 89E8660850
Subject: Re: [PATCH] objtool: Allow AR to be overridden with HOSTAR
To:     Nathan Chancellor <natechancellor@gmail.com>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>
Cc:     Nick Desaulniers <ndesaulniers@google.com>,
        clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org
References: <20190514224047.28505-1-natechancellor@gmail.com>
From:   Mukesh Ojha <mojha@codeaurora.org>
Message-ID: <2bdc6dfa-bbe8-208f-fab5-30d67573345c@codeaurora.org>
Date:   Wed, 15 May 2019 18:05:30 +0530
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
 Thunderbird/60.6.1
MIME-Version: 1.0
In-Reply-To: <20190514224047.28505-1-natechancellor@gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-US
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk


On 5/15/2019 4:10 AM, Nathan Chancellor wrote:
> Currently, this Makefile hardcodes GNU ar, meaning that if it is not
> available, there is no way to supply a different one and the build will
> fail.
>
> $ make AR=llvm-ar CC=clang LD=ld.lld HOSTAR=llvm-ar HOSTCC=clang \
>         HOSTLD=ld.lld HOSTLDFLAGS=-fuse-ld=lld defconfig modules_prepare
> ...
>    AR       /out/tools/objtool/libsubcmd.a
> /bin/sh: 1: ar: not found
> ...
>
> Follow the logic of HOST{CC,LD} and allow the user to specify a
> different ar tool via HOSTAR (which is used elsewhere in other
> tools/ Makefiles).
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/481
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>


Nice catch.
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>

Cheers,
-Mukesh

> ---
>   tools/objtool/Makefile | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/objtool/Makefile b/tools/objtool/Makefile
> index 53f8be0f4a1f..88158239622b 100644
> --- a/tools/objtool/Makefile
> +++ b/tools/objtool/Makefile
> @@ -7,11 +7,12 @@ ARCH := x86
>   endif
>   
>   # always use the host compiler
> +HOSTAR	?= ar
>   HOSTCC	?= gcc
>   HOSTLD	?= ld
> +AR	 = $(HOSTAR)
>   CC	 = $(HOSTCC)
>   LD	 = $(HOSTLD)
> -AR	 = ar
>   
>   ifeq ($(srctree),)
>   srctree := $(patsubst %/,%,$(dir $(CURDIR)))