On Fri, Aug 6, 2021 at 3:46 AM Nathan Chancellor [off-list ref] wrote:

On 8/5/2021 8:01 AM, Masahiro Yamada wrote:

quoted

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>

Reviewed-by: Nathan Chancellor <nathan@kernel.org>

Applied to linux-kbuild.

quoted

---

  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

-- 
Best Regards
Masahiro Yamada