Selftests fail to build on several distros/architectures because of
missing headers files.
On a Ubuntu/x86_64 some missing headers are:
asm/byteorder.h, asm/socket.h, asm/sockios.h
On a Debian/arm32 build already fails at sys/cdefs.h
In both cases, these already exist in /usr/include/<arch-specific-dir>,
but Clang does not include these when using '-target bpf' flag,
since it is no longer compiling against the host architecture.
The solution is to:
- run Clang without '-target bpf' and extract the include chain for the
current system
- add these to the bpf build with '-idirafter'
The choice of -idirafter is to catch this error without injecting
unexpected include behavior: if an arch-specific tree is built
for bpf in the future, this will be correctly found by Clang.
Signed-off-by: Sirio Balmelli <si...@b-ad.ch>
---
tools/testing/selftests/bpf/Makefile | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/tools/testing/selftests/bpf/Makefile
b/tools/testing/selftests/bpf/Makefile
index 1eb0fa2aba92..e0c8d3cdc6c9 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -84,7 +84,16 @@ else
CPU ?= generic
endif
+# Get Clang's default includes on this system, as opposed to those seen by
'-target bpf'.
+# This fixes "missing" files on some architectures/distros,
+#+ such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
+# Use '-idirafter': don't interfere with include mechanics
+#+ except where the build would have failed anyways.
+CLANG_SYS_INCLUDES := $(shell $(CLANG) -v -E - </dev/null 2>&1 \
+ | sed -n '/<...> search starts here:/,/End of search list./{ s|
\(/.*\)|-idirafter \1|p }')
+
CLANG_FLAGS = -I. -I./include/uapi -I../../../include/uapi \
+ $(CLANG_SYS_INCLUDES) \
-Wno-compare-distinct-pointer-types
$(OUTPUT)/test_l4lb_noinline.o: CLANG_FLAGS += -fno-inline
--
2.16.2
