[PATCH v1] perf build: Add system include paths to BPF builds

[Namhyung Kim]

Hi Ian,

On Fri, May 5, 2023 at 7:15 PM Ian Rogers <irogers at google.com> wrote:
>
> There are insufficient headers in tools/include to satisfy building
> BPF programs and their header dependencies. Add the system include
> paths from the non-BPF clang compile so that these headers can be
> found.
>
> This code was taken from:
> tools/testing/selftests/bpf/Makefile
>
> Signed-off-by: Ian Rogers <irogers at google.com>

Thanks, this fixes the BPF build failure on my machine.

Tested-by: Namhyung Kim <namhyung at kernel.org>

Thanks,
Namhyung


> ---
>  tools/perf/Makefile.perf | 20 +++++++++++++++++++-
>  1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
> index 61c33d100b2b..37befdfa8ac8 100644
> --- a/tools/perf/Makefile.perf
> +++ b/tools/perf/Makefile.perf
> @@ -1057,7 +1057,25 @@ $(SKEL_TMP_OUT) $(LIBAPI_OUTPUT) $(LIBBPF_OUTPUT) $(LIBPERF_OUTPUT) $(LIBSUBCMD_
>
>  ifndef NO_BPF_SKEL
>  BPFTOOL := $(SKEL_TMP_OUT)/bootstrap/bpftool
> -BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(LIBBPF_INCLUDE)
> +
> +# Get Clang's default includes on this system, as opposed to those seen by
> +# '-target bpf'. This fixes "missing" files on some architectures/distros,
> +# such as asm/byteorder.h, asm/socket.h, asm/sockios.h, sys/cdefs.h etc.
> +#
> +# Use '-idirafter': Don't interfere with include mechanics except where the
> +# build would have failed anyways.
> +define get_sys_includes
> +$(shell $(1) $(2) -v -E - </dev/null 2>&1 \
> +       | sed -n '/<...> search starts here:/,/End of search list./{ s| \(/.*\)|-idirafter \1|p }') \
> +$(shell $(1) $(2) -dM -E - </dev/null | grep '__riscv_xlen ' | awk '{printf("-D__riscv_xlen=%d -D__BITS_PER_LONG=%d", $$3, $$3)}')
> +endef
> +
> +ifneq ($(CROSS_COMPILE),)
> +CLANG_TARGET_ARCH = --target=$(notdir $(CROSS_COMPILE:%-=%))
> +endif
> +
> +CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG),$(CLANG_TARGET_ARCH))
> +BPF_INCLUDE := -I$(SKEL_TMP_OUT)/.. -I$(LIBBPF_INCLUDE) $(CLANG_SYS_INCLUDES)
>
>  $(BPFTOOL): | $(SKEL_TMP_OUT)
>         $(Q)CFLAGS= $(MAKE) -C ../bpf/bpftool \
> --
> 2.40.1.521.gf1e218fcd8-goog
>