Commit 7e20e47c authored Apr 08, 2020 by Masahiro Yamada

kbuild: replace AS=clang with LLVM_IAS=1



The 'AS' variable is unused for building the kernel. Only the remaining
usage is to turn on the integrated assembler. A boolean flag is a better
fit for this purpose.

AS=clang was added for experts. So, I replaced it with LLVM_IAS=1,
breaking the backward compatibility.

Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

parent 76426e23

Documentation/kbuild/llvm.rst

+4 −1

Original line number	Diff line number	Diff line
		@@ -50,11 +50,14 @@ LLVM Utilities
		LLVM has substitutes for GNU binutils utilities. These can be invoked as
		additional parameters to `make`.

		make CC=clang AS=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
		make CC=clang LD=ld.lld AR=llvm-ar NM=llvm-nm STRIP=llvm-strip \\
		OBJCOPY=llvm-objcopy OBJDUMP=llvm-objdump OBJSIZE=llvm-size \\
		READELF=llvm-readelf HOSTCC=clang HOSTCXX=clang++ HOSTAR=llvm-ar \\
		HOSTLD=ld.lld

		Currently, the integrated assembler is disabled by default. You can pass
		`LLVM_IAS=1` to enable it.

		Getting Help
		------------

Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -538,7 +538,7 @@ endif
		ifneq ($(GCC_TOOLCHAIN),)
		CLANG_FLAGS += --gcc-toolchain=$(GCC_TOOLCHAIN)
		endif
		ifeq ($(if $(AS),$(shell $(AS) --version 2>&1 \| head -n 1 \| grep clang)),)
		ifneq ($(LLVM_IAS),1)
		CLANG_FLAGS += -no-integrated-as
		endif
		CLANG_FLAGS += -Werror=unknown-warning-option