Add cross target to CC if using clang. Also add custom gcc toolchain path for fallback gcc tools. COMPILER is previously set to "clang" if CC=clang was set from the make command line. So -target and -gcc-toolchain can be added to CC, since we already know that it is set. Clang will fallback to using things like ld, as, and libgcc if (respectively) one of the llvm linkers isn't available, the integrated assembler is turned off, or an appropriately cross-compiled version of compiler-rt isn't available. To this end, you can specify the path to this fallback gcc toolchain with GCC_TOOLCHAIN. From: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx> Signed-off-by: Behan Webster <behanw@xxxxxxxxxxxxxxxxxx> Reviewed-by: Jan-Simon Möller <dl9pf@xxxxxx> Reviewed-by: Mark Charlebois <charlebm@xxxxxxxxx> Signed-off-by: Greg Hackmann <ghackmann@xxxxxxxxxx> Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx> --- Makefile | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) diff --git a/Makefile b/Makefile index b2faa9319372..b0f6ef67028d 100644 --- a/Makefile +++ b/Makefile @@ -375,6 +375,16 @@ LDFLAGS_vmlinux = CFLAGS_GCOV = -fprofile-arcs -ftest-coverage -fno-tree-loop-im -Wno-maybe-uninitialized CFLAGS_KCOV := $(call cc-option,-fsanitize-coverage=trace-pc,) +ifeq ($(cc-name),clang) +ifneq ($(CROSS_COMPILE),) +CLANG_TARGET := -target $(notdir $(CROSS_COMPILE:%-=%)) +GCC_TOOLCHAIN := $(dir $(CROSS_COMPILE)) +endif +ifneq ($(GCC_TOOLCHAIN),) +CLANG_GCC_TC := -gcc-toolchain $(GCC_TOOLCHAIN) +endif +CLANG_FLAGS := $(CLANG_TARGET) $(CLANG_GCC_TC) +endif # Use USERINCLUDE when you must reference the UAPI directories only. USERINCLUDE := \ @@ -395,18 +405,18 @@ LINUXINCLUDE := \ LINUXINCLUDE += $(filter-out $(LINUXINCLUDE),$(USERINCLUDE)) -KBUILD_CPPFLAGS := -D__KERNEL__ +KBUILD_CPPFLAGS := -D__KERNEL__ $(CLANG_FLAGS) KBUILD_CFLAGS := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \ -fno-strict-aliasing -fno-common \ -Werror-implicit-function-declaration \ -Wno-format-security \ - -std=gnu89 $(call cc-option,-fno-PIE) - + -std=gnu89 $(call cc-option,-fno-PIE) \ + $(CLANG_FLAGS) KBUILD_AFLAGS_KERNEL := KBUILD_CFLAGS_KERNEL := -KBUILD_AFLAGS := -D__ASSEMBLY__ $(call cc-option,-fno-PIE) +KBUILD_AFLAGS := -D__ASSEMBLY__ $(call cc-option,-fno-PIE) $(CLANG_FLAGS) KBUILD_AFLAGS_MODULE := -DMODULE KBUILD_CFLAGS_MODULE := -DMODULE KBUILD_LDFLAGS_MODULE := -T $(srctree)/scripts/module-common.lds -- 2.12.1.578.ge9c3154ca4-goog -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
