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In-Reply-To: <20220719170555.2576993-2-roberto.sassu@huawei.com>
From:   Quentin Monnet <quentin@isovalent.com>
Date:   Wed, 20 Jul 2022 21:07:53 +0100
Message-ID: <CACdoK4LMvLyV2z5quN1BE4VrxGJK-f1YfuHWoQrJaH_eKyHZog@mail.gmail.com>
Subject: Re: [PATCH 2/4] bpftool: Complete libbfd feature detection
To:     Roberto Sassu <roberto.sassu@huawei.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        terrelln@fb.com, Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        bpf <bpf@vger.kernel.org>,
        "linux-perf-use." <linux-perf-users@vger.kernel.org>,
        llvm@lists.linux.dev, open list <linux-kernel@vger.kernel.org>
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On Tue, 19 Jul 2022 at 18:06, Roberto Sassu <roberto.sassu@huawei.com> wrote:
>
> Commit 6e8ccb4f624a7 ("tools/bpf: properly account for libbfd variations")
> sets the linking flags depending on which flavor of the libbfd feature was
> detected.
>
> However, the flavors except libbfd cannot be detected, as they are not in
> the feature list.
>
> Complete the list of features to detect by adding libbfd-liberty and
> libbfd-liberty-z.
>
> Fixes: 6e8ccb4f624a7 ("tools/bpf: properly account for libbfd variations")
> Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> ---
>  tools/bpf/bpftool/Makefile | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/tools/bpf/bpftool/Makefile b/tools/bpf/bpftool/Makefile
> index 6b5b3a99f79d..4b09a5c3b9f1 100644
> --- a/tools/bpf/bpftool/Makefile
> +++ b/tools/bpf/bpftool/Makefile
> @@ -93,8 +93,10 @@ INSTALL ?= install
>  RM ?= rm -f
>
>  FEATURE_USER = .bpftool
> -FEATURE_TESTS = libbfd disassembler-four-args libcap clang-bpf-co-re
> -FEATURE_DISPLAY = libbfd disassembler-four-args libcap clang-bpf-co-re
> +FEATURE_TESTS = libbfd libbfd-liberty libbfd-liberty-z \
> +               disassembler-four-args libcap clang-bpf-co-re
> +FEATURE_DISPLAY = libbfd libbfd-liberty libbfd-liberty-z \
> +                 disassembler-four-args libcap clang-bpf-co-re

Do you know if there is a way to fold the different feature-libbfd-*
features into a single one for FEATURE_DISPLAY? Or should the various
features be all moved under feature-libbfd with multiple attempts,
like you did for disassembler-four-args in patch 1? My concern is that
users may think some features could be missing when they compile and
see that detection fails for some items.