From: Masahiro Yamada <masahiroy@kernel.org>
To: linux-kbuild@vger.kernel.org
Cc: Masahiro Yamada <masahiroy@kernel.org>,
Albert Ou <aou@eecs.berkeley.edu>,
Michal Marek <michal.lkml@markovi.net>,
Nathan Chancellor <nathan@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
clang-built-linux@googlegroups.com, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: [PATCH] kbuild: check CONFIG_AS_IS_LLVM instead of LLVM_IAS
Date: Fri, 6 Aug 2021 00:01:02 +0900 [thread overview]
Message-ID: <20210805150102.131008-1-masahiroy@kernel.org> (raw)
LLVM_IAS is the user interface to set the -(no-)integrated-as flag,
and it should be used only for that purpose.
LLVM_IAS is checked in some places to determine the assembler type,
but it is not precise.
$ make CC=gcc LLVM_IAS=1
... will use the GNU assembler since LLVM_IAS=1 is effective only when
$(CC) is clang.
Of course, the combination of CC=gcc and LLVM_IAS=1 does not make
sense, but the build system can be more robust against such insane
input.
Commit ba64beb17493a ("kbuild: check the minimum assembler version in
Kconfig") introduced CONFIG_AS_IS_GNU/LLVM, which is more precise
because Kconfig checks the version string from the assembler in use.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
Makefile | 2 +-
arch/riscv/Makefile | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/Makefile b/Makefile
index 4ab151060931..8b56c9692c3c 100644
--- a/Makefile
+++ b/Makefile
@@ -844,7 +844,7 @@ else
DEBUG_CFLAGS += -g
endif
-ifneq ($(LLVM_IAS),1)
+ifndef CONFIG_AS_IS_LLVM
KBUILD_AFLAGS += -Wa,-gdwarf-2
endif
diff --git a/arch/riscv/Makefile b/arch/riscv/Makefile
index bc74afdbf31e..dcfbd2a87d41 100644
--- a/arch/riscv/Makefile
+++ b/arch/riscv/Makefile
@@ -41,7 +41,7 @@ endif
ifeq ($(CONFIG_LD_IS_LLD),y)
KBUILD_CFLAGS += -mno-relax
KBUILD_AFLAGS += -mno-relax
-ifneq ($(LLVM_IAS),1)
+ifndef CONFIG_AS_IS_LLVM
KBUILD_CFLAGS += -Wa,-mno-relax
KBUILD_AFLAGS += -Wa,-mno-relax
endif
--
2.30.2
next reply other threads:[~2021-08-05 15:02 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-05 15:01 Masahiro Yamada [this message]
2021-08-05 18:22 ` [PATCH] kbuild: check CONFIG_AS_IS_LLVM instead of LLVM_IAS Nick Desaulniers
2021-08-05 18:46 ` Nathan Chancellor
2021-08-10 0:05 ` Masahiro Yamada
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