Messages in this thread Patch in this message | | | From | Matthias Kaehlcke <> | Subject | [PATCH v2] kbuild: Add better clang cross build support | Date | Fri, 21 Apr 2017 11:20:01 -0700 |
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Add cross target to CC if using clang. Also add custom gcc toolchain path for fallback gcc tools.
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@converseincode.com> Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de> Reviewed-by: Mark Charlebois <charlebm@gmail.com> Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Matthias Kaehlcke <mka@chromium.org> --- Changes in v2: - Moved new 'code' into existing ifeq clang block - Don't add -target and -gcc-toolchain to KBUILD_CPPFLAGS - Removed intermediate CLANG_FLAGS variable - Updated commit message, removed paragraph mentioning old COMPILER variable
Makefile | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/Makefile b/Makefile index 5039b9148d15..11c00bd3ec0c 100644 --- a/Makefile +++ b/Makefile @@ -698,6 +698,15 @@ endif KBUILD_CFLAGS += $(stackp-flag) ifeq ($(cc-name),clang) +ifneq ($(CROSS_COMPILE),) +CLANG_TARGET := -target $(notdir $(CROSS_COMPILE:%-=%)) +GCC_TOOLCHAIN := $(realpath $(dir $(shell which $(LD)))/..) +endif +ifneq ($(GCC_TOOLCHAIN),) +CLANG_GCC_TC := -gcc-toolchain $(GCC_TOOLCHAIN) +endif +KBUILD_CFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) +KBUILD_AFLAGS += $(CLANG_TARGET) $(CLANG_GCC_TC) KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,) KBUILD_CPPFLAGS += $(call cc-option,-Wno-unknown-warning-option,) KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable) -- 2.12.2.816.g2cccc81164-goog
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