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authorNick Desaulniers <ndesaulniers@google.com>2017-11-06 10:47:54 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-24 11:01:29 +0100
commit957435b566c9d14afa3cb957b2ba7b57c6eda787 (patch)
tree9eb0c0502e4751a80ac755bf3f9ccaf23129aca1
parente82496fbe3a08489ffbbbcdf995be8aec575428d (diff)
kbuild: fix linker feature test macros when cross compiling with Clang
commit 86a9df597cdd564d2d29c65897bcad42519e3678 upstream. I was not seeing my linker flags getting added when using ld-option when cross compiling with Clang. Upon investigation, this seems to be due to a difference in how GCC vs Clang handle cross compilation. GCC is configured at build time to support one backend, that is implicit when compiling. Clang is explicit via the use of `-target <triple>` and ships with all supported backends by default. GNU Make feature test macros that compile then link will always fail when cross compiling with Clang unless Clang's triple is passed along to the compiler. For example: $ clang -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: unknown architecture of input file `temp.o' is incompatible with aarch64 output aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 0000000000400078 $ echo $? 1 $ clang -target aarch64-linux-android- -x c /dev/null -c -o temp.o $ aarch64-linux-android/bin/ld -E temp.o aarch64-linux-android/bin/ld: warning: cannot find entry symbol _start; defaulting to 00000000004002e4 $ echo $? 0 This causes conditional checks that invoke $(CC) without the target triple, then $(LD) on the result, to always fail. Suggested-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--scripts/Kbuild.include5
1 files changed, 3 insertions, 2 deletions
diff --git a/scripts/Kbuild.include b/scripts/Kbuild.include
index 9ffd3dda3889..97769465de13 100644
--- a/scripts/Kbuild.include
+++ b/scripts/Kbuild.include
@@ -160,12 +160,13 @@ cc-if-fullversion = $(shell [ $(cc-fullversion) $(1) $(2) ] && echo $(3) || echo
# cc-ldoption
# Usage: ldflags += $(call cc-ldoption, -Wl$(comma)--hash-style=both)
cc-ldoption = $(call try-run,\
- $(CC) $(1) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
+ $(CC) $(1) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -nostdlib -x c /dev/null -o "$$TMP",$(1),$(2))
# ld-option
# Usage: LDFLAGS += $(call ld-option, -X)
ld-option = $(call try-run,\
- $(CC) -x c /dev/null -c -o "$$TMPO" ; $(LD) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
+ $(CC) $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) -x c /dev/null -c -o "$$TMPO"; \
+ $(LD) $(LDFLAGS) $(1) "$$TMPO" -o "$$TMP",$(1),$(2))
# ar-option
# Usage: KBUILD_ARFLAGS := $(call ar-option,D)