Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
MIME-Version: 1.0
References: <20230606-fix-as-option-after-clang_flags-move-v1-1-a7f7b23a35e3@kernel.org>
In-Reply-To: <20230606-fix-as-option-after-clang_flags-move-v1-1-a7f7b23a35e3@kernel.org>
From:   Naresh Kamboju <naresh.kamboju@linaro.org>
Date:   Wed, 7 Jun 2023 16:30:19 +0530
Message-ID: <CA+G9fYs8HCjaBzTDdXsQoEt3KP5rS=M34awGs8em7Jmx=yQkkw@mail.gmail.com>
Subject: Re: [PATCH] kbuild: Add KBUILD_CPPFLAGS to as-option invocation
To:     Nathan Chancellor <nathan@kernel.org>
Cc:     masahiroy@kernel.org, ndesaulniers@google.com, nicolas@fjasle.eu,
        trix@redhat.com, linux-kbuild@vger.kernel.org,
        linux-kernel@vger.kernel.org, llvm@lists.linux.dev,
        patches@lists.linux.dev,
        Linux Kernel Functional Testing <lkft@linaro.org>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Wed, 7 Jun 2023 at 04:10, Nathan Chancellor <nathan@kernel.org> wrote:
>
> After commit feb843a469fb ("kbuild: add $(CLANG_FLAGS) to
> KBUILD_CPPFLAGS"), there is an error while building certain PowerPC
> assembly files with clang:
>
>   arch/powerpc/lib/copypage_power7.S: Assembler messages:
>   arch/powerpc/lib/copypage_power7.S:34: Error: junk at end of line: `0b01000'
>   arch/powerpc/lib/copypage_power7.S:35: Error: junk at end of line: `0b01010'
>   arch/powerpc/lib/copypage_power7.S:37: Error: junk at end of line: `0b01000'
>   arch/powerpc/lib/copypage_power7.S:38: Error: junk at end of line: `0b01010'
>   arch/powerpc/lib/copypage_power7.S:40: Error: junk at end of line: `0b01010'
>   clang: error: assembler command failed with exit code 1 (use -v to see invocation)
>
> as-option only uses KBUILD_AFLAGS, so after removing CLANG_FLAGS from
> KBUILD_AFLAGS, there is no more '--target=' or '--prefix=' flags. As a
> result of those missing flags, the host target
> will be tested during as-option calls and likely fail, meaning necessary
> flags may not get added when building assembly files, resulting in
> errors like seen above.
>
> Add KBUILD_CPPFLAGS to as-option invocations to clear up the errors.
> This should have been done in commit d5c8d6e0fa61 ("kbuild: Update
> assembler calls to use proper flags and language target"), which
> switched from using the assembler target to the assembler-with-cpp
> target, so flags that affect preprocessing are passed along in all
> relevant tests. as-option now mirrors cc-option.
>
> Fixes: feb843a469fb ("kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGS")
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Closes: https://lore.kernel.org/CA+G9fYs=koW9WardsTtora+nMgLR3raHz-LSLr58tgX4T5Mxag@mail.gmail.com/
> Signed-off-by: Nathan Chancellor <nathan@kernel.org>

Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>

This proposed fix patch applied on top of Linux next and
built with clang and build test pass.
https://storage.tuxsuite.com/public/linaro/naresh/builds/2QsEzqEij2M3F1JkQAQfhpIpsXG/

> ---
>  scripts/Makefile.compiler | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/Makefile.compiler b/scripts/Makefile.compiler
> index 437013f8def3..e31f18625fcf 100644
> --- a/scripts/Makefile.compiler
> +++ b/scripts/Makefile.compiler
> @@ -32,7 +32,7 @@ try-run = $(shell set -e;             \
>  # Usage: aflags-y += $(call as-option,-Wa$(comma)-isa=foo,)
>
>  as-option = $(call try-run,\
> -       $(CC) -Werror $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2))
> +       $(CC) -Werror $(KBUILD_CPPFLAGS) $(KBUILD_AFLAGS) $(1) -c -x assembler-with-cpp /dev/null -o "$$TMP",$(1),$(2))
>
>  # as-instr
>  # Usage: aflags-y += $(call as-instr,instr,option1,option2)
>
> ---
> base-commit: feb843a469fb0ab00d2d23cfb9bcc379791011bb
> change-id: 20230606-fix-as-option-after-clang_flags-move-be88e993cbaa
>
> Best regards,
> --
> Nathan Chancellor <nathan@kernel.org>

Best regards
Naresh Kamboju