kbuild: check CONFIG_AS_IS_LLVM instead of LLVM_IAS

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.

For example,

 $ make CC=gcc LLVM_IAS=1

... will use the GNU assembler (i.e. binutils) since LLVM_IAS=1 is
effective only when $(CC) is clang.

Of course, 'CC=gcc LLVM_IAS=1' is an odd combination, 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: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>

diff --git a/Makefile b/Makefile
index f5419ce..891866a 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -843,7 +843,7 @@ 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 bc74afd..dcfbd2a 100644 (file)
--- 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