selftests/bpf: Makefile fix "missing" headers on build with -idirafter

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 <sirio@b-ad.ch>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
This commit is contained in:
Sirio Balmelli 2018-05-21 09:00:03 +02:00 committed by Daniel Borkmann
parent ff4fb475ce
commit 167381f3ea

View File

@ -84,7 +84,17 @@ 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