On Fri, Nov 1, 2024 at 1:38 AM Viktor Malik <vmalik@xxxxxxxxxx> wrote:
>
> When trying to build BPF selftests with additional compiler and linker
> flags, we're running into multiple problems. This series addresses all
> of them:
>
> - CFLAGS are not passed to sub-makes of bpftool and libbpf. This is a
> problem when compiling with PIE as libbpf.a ends up being non-PIE and
> cannot be linked with other binaries (patch #1).
>
> - bpftool Makefile runs `llvm-config --cflags` and appends the result to
> CFLAGS. The result typically contains `-D_GNU_SOURCE` which may be
> already set in CFLAGS. That causes a compilation error (patch #2).
>
> - Some GCC flags are not supported by Clang but there are binaries which
> are always built with Clang but reuse user-defined CFLAGS. When CFLAGS
> contain such flags, compilation fails (patch #3).
>
> Changelog:
> ----------
> v2 -> v3:
> - resolve conflicts between patch #1 and 4192bb294f80 ("selftests/bpf:
> Provide a generic [un]load_module helper")
> - add Quentin's and Jiri's acks for patches #2 and #3
>
> v1 -> v2:
> - cover forgotten case in patch#1 (noted by Eduard)
> - remove -D_GNU_SOURCE unconditionally in patch#2 (suggested by Andrii)
> - rewrite patch#3 to just add -Wno-unused-command-line-argument
> (suggested by Andrii)
>
> Viktor Malik (3):
> selftests/bpf: Allow building with extra flags
> bpftool: Prevent setting duplicate _GNU_SOURCE in Makefile
> selftests/bpf: Disable warnings on unused flags for Clang builds
>
I've applied the last two patches, they seem to be independent from
the first, right?
> tools/bpf/bpftool/Makefile | 6 ++++-
> tools/testing/selftests/bpf/Makefile | 36 +++++++++++++++++++---------
> 2 files changed, 30 insertions(+), 12 deletions(-)
>
> --
> 2.47.0
>
>
