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authorBehan Webster <behanw@converseincode.com>2017-04-21 21:20:01 +0300
committerMasahiro Yamada <yamada.masahiro@socionext.com>2017-04-23 10:14:46 +0300
commit785f11aa595bc3d4e74096cbd598ada54ecc0d81 (patch)
tree073e9b6a9d466574250560cca596b971b9e97723 /Makefile
parenta0ae981eba8f07dbc74bce38fd3a462b69a5bc8e (diff)
downloadlinux-785f11aa595bc3d4e74096cbd598ada54ecc0d81.tar.xz
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>
Diffstat (limited to 'Makefile')
-rw-r--r--Makefile9
1 files changed, 9 insertions, 0 deletions
diff --git a/Makefile b/Makefile
index f178b9a7b56f..88d607245791 100644
--- a/Makefile
+++ b/Makefile
@@ -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)