Commit 785f11aa authored Apr 21, 2017 by Behan Webster Committed by Masahiro Yamada Apr 23, 2017

kbuild: Add better clang cross build support



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.

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>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

parent a0ae981e

Makefile

+9 −0

Original line number	Diff line number	Diff line
		@@ -688,6 +688,15 @@ 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_CFLAGS += $(call cc-disable-warning, unused-variable)
		KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)