[PATCH v2 2/2] kbuild: consolidate Clang compiler flags

[Nick Desaulniers]

On Mon, Nov 5, 2018 at 7:05 PM Masahiro Yamada
<yamada.masahiro at socionext.com> wrote:
>
> Collect basic Clang options such as --target, --prefix, --gcc-toolchain,
> -no-integrated-as into a single variable CLANG_FLAGS so that it can be
> easily reused in other parts of Makefile.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
>
> Changes in v2:
>  - Use := flavor instead of = because $(CLANG_FLAGS) is expanded soon anyway
>
>  Makefile | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
>
> diff --git a/Makefile b/Makefile
> index da11700..e173a73 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -487,18 +487,17 @@ endif
>
>  ifneq ($(shell $(CC) --version 2>&1 | head -n 1 | grep clang),)
>  ifneq ($(CROSS_COMPILE),)
> -CLANG_TARGET   := --target=$(notdir $(CROSS_COMPILE:%-=%))
> +CLANG_FLAGS    := --target=$(notdir $(CROSS_COMPILE:%-=%))
>  GCC_TOOLCHAIN_DIR := $(dir $(shell which $(LD)))
> -CLANG_PREFIX   := --prefix=$(GCC_TOOLCHAIN_DIR)
> +CLANG_FLAGS    += --prefix=$(GCC_TOOLCHAIN_DIR)
>  GCC_TOOLCHAIN  := $(realpath $(GCC_TOOLCHAIN_DIR)/..)
>  endif
>  ifneq ($(GCC_TOOLCHAIN),)
> -CLANG_GCC_TC   := --gcc-toolchain=$(GCC_TOOLCHAIN)
> +CLANG_FLAGS    += --gcc-toolchain=$(GCC_TOOLCHAIN)
>  endif
> -KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX)
> -KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) $(CLANG_PREFIX)
> -KBUILD_CFLAGS += -no-integrated-as
> -KBUILD_AFLAGS += -no-integrated-as
> +CLANG_FLAGS    += -no-integrated-as
> +KBUILD_CFLAGS  += $(CLANG_FLAGS)
> +KBUILD_AFLAGS  += $(CLANG_FLAGS)
>  endif
>
>  RETPOLINE_CFLAGS_GCC := -mindirect-branch=thunk-extern -mindirect-branch-register
> --
> 2.7.4
>

Thanks for this patch, Masahiro, it's a good simplification.
Reviewed-by: Nick Desaulniers <ndesaulniers at google.com>
Tested-by: Nick Desaulniers <ndesaulniers at google.com>

Would you mind waiting for a tested-by from Stefan, and maybe an ack
from Greg (added to cc)?
-- 
Thanks,
~Nick Desaulniers