From: Masahiro Yamada <masahiroy@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Michal Marek <michal.lkml@markovi.net>,
Nick Desaulniers <ndesaulniers@google.com>,
Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
clang-built-linux <clang-built-linux@googlegroups.com>
Subject: Re: [PATCH 2/2] Makefile: Only specify '--prefix=' when building with clang + GNU as
Date: Wed, 10 Mar 2021 04:55:00 +0900 [thread overview]
Message-ID: <CAK7LNARd7pM7SCKJOS=_ZDE+-Q_buDOfw_u0vsfof6G1FWXvOQ@mail.gmail.com> (raw)
In-Reply-To: <20210302210646.3044738-2-nathan@kernel.org>
On Wed, Mar 3, 2021 at 6:07 AM Nathan Chancellor <nathan@kernel.org> 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>
I was tricked by a couple of Reviewed-by/Tested-by tags.
With this patch applied, the code looks as follows:
ifneq ($(CROSS_COMPILE),)
CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
ifneq ($(LLVM_IAS),1)
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
CLANG_FLAGS += -no-integrated-as
endif
endif
For the native build (empty CROSS_COMPILE),
you cannot add -no-integrated-as.
I dropped this from my tree.
Is the correct code as follows?
ifneq ($(LLVM_IAS),1)
CLANG_FLAGS += -no-integrated-as
ifneq ($(CROSS_COMPILE),)
CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
endif
endif
> ---
> Makefile | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index c20f0ad8be73..0413b8c594cd 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -566,12 +566,12 @@ CC_VERSION_TEXT = $(shell $(CC) --version 2>/dev/null | head -n 1 | sed 's/\#//g
> ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
> ifneq ($(CROSS_COMPILE),)
> CLANG_FLAGS += --target=$(notdir $(CROSS_COMPILE:%-=%))
> +ifneq ($(LLVM_IAS),1)
> GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE)elfedit))
> CLANG_FLAGS += --prefix=$(GCC_TOOLCHAIN_DIR)$(notdir $(CROSS_COMPILE))
> -endif
> -ifneq ($(LLVM_IAS),1)
> CLANG_FLAGS += -no-integrated-as
> endif
> +endif
> CLANG_FLAGS += -Werror=unknown-warning-option
> KBUILD_CFLAGS += $(CLANG_FLAGS)
> KBUILD_AFLAGS += $(CLANG_FLAGS)
> --
> 2.31.0.rc0.75.gec125d1bc1
>
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2021-03-09 19:56 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-02 21:06 [PATCH 1/2] Makefile: Remove '--gcc-toolchain' flag Nathan Chancellor
2021-03-02 21:06 ` [PATCH 2/2] Makefile: Only specify '--prefix=' when building with clang + GNU as Nathan Chancellor
2021-03-02 22:02 ` Fangrui Song
2021-03-02 22:09 ` Nick Desaulniers
2021-03-02 22:40 ` Nick Desaulniers
2021-03-09 19:55 ` Masahiro Yamada [this message]
2021-03-09 19:58 ` Masahiro Yamada
2021-09-29 17:26 ` kernel test robot
2021-09-29 19:32 ` kernel test robot
2021-03-02 21:43 ` [PATCH 1/2] Makefile: Remove '--gcc-toolchain' flag Fangrui Song
2021-03-03 8:33 ` Masahiro Yamada
2021-03-02 22:33 ` Nick Desaulniers
2021-03-03 3:25 ` Sedat Dilek
2021-03-03 14:22 ` Sedat Dilek
2021-03-09 20:59 ` [PATCH v2 " Nathan Chancellor
2021-03-09 20:59 ` [PATCH v2 2/2] Makefile: Only specify '--prefix=' when building with clang + GNU as Nathan Chancellor
2021-03-09 21:15 ` [PATCH v2 1/2] Makefile: Remove '--gcc-toolchain' flag Fangrui Song
2021-03-15 16:21 ` Masahiro Yamada
2021-03-15 16:41 ` Sedat Dilek
2021-03-16 15:36 ` Masahiro Yamada
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