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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Tue, 9 May 2023 12:52:32 -0700
Message-ID: <CAM9d7cgJT4nZyAFLSZ600T7xwOMKTPF+wKn0So6NqPjtwLduRg@mail.gmail.com>
Subject: Re: [PATCH 1/1] perf build: Gracefully fail the build if
 BUILD_BPF_SKEL=1 is specified and clang isn't available
To:     arnaldo.melo@gmail.com
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        Andrii Nakryiko <andrii.nakryiko@gmail.com>,
        Ian Rogers <irogers@google.com>,
        Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
        Song Liu <songliubraving@meta.com>,
        Yang Jihong <yangjihong1@huawei.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        linux-perf-users@vger.kernel.org
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Hi Arnaldo,

On Tue, May 9, 2023 at 11:54 AM <arnaldo.melo@gmail.com> wrote:
>
> Namhyung,
>
>         The one you acked disabled the build and emitted a warning, but
> then that was when we were trying to have BUILD_BPF_SKEL=1 as default,
> this one is for the current situation, where we need to explicitely ask
> for those features by explicitely adding BUILD_BPF_SKEL=1 to the make
> command line, I think I can keep your Acked-by, right?

Sure thing!

Thanks,
Namhyung


> ---
>
> Build BPF skels require having a compiler able to generate BPF bytecode,
> and so far this is only possible with clang, so check for its
> availability and fail the build when the user explicitely ask for BPF
> skels to be built.
>
> Acked-by: Namhyung Kim <namhyung@kernel.org>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
> Cc: Ian Rogers <irogers@google.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Song Liu <songliubraving@meta.com>
> Cc: Yang Jihong <yangjihong1@huawei.com>,
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
> ---
>  tools/perf/Makefile.config | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 4884520f954f4b2a..70268442f7eeca50 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -216,6 +216,12 @@ ifeq ($(call get-executable,$(BISON)),)
>    dummy := $(error Error: $(BISON) is missing on this system, please install it)
>  endif
>
> +ifeq ($(BUILD_BPF_SKEL),1)
> +  ifeq ($(call get-executable,$(CLANG)),)
> +    dummy := $(error $(CLANG) is missing on this system, please install it to be able to build with BUILD_BPF_SKEL=1)
> +  endif
> +endif
> +
>  ifneq ($(OUTPUT),)
>    ifeq ($(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \>\= 371), 1)
>      BISON_FILE_PREFIX_MAP := --file-prefix-map=$(OUTPUT)=
> --
> 2.39.2
>