kbuild: consolidate Clang compiler flags

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@socionext.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Greg Hackmann <ghackmann@google.com>

diff --git a/Makefile b/Makefile
index b71b9c70496cc4674366bf2f93687c79865c41e7..c300ac16c895e336b894824abf938af37da6d964 100644 (file)
--- 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