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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Mon, 4 Dec 2023 16:10:24 -0800
Message-ID: <CAM9d7cgdUfdMnhmMpqnkpJyV5hJE9dgGuwPetSNM0KfDuYfs6A@mail.gmail.com>
Subject: Re: [PATCH 36/48] perf annotate-data: Introduce struct data_loc_info
To:     Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-perf-users <linux-perf-users@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephane Eranian <eranian@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-toolchains@vger.kernel.org, linux-trace-devel@vger.kernel.org
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Hello,

On Sun, Dec 3, 2023 at 8:22 AM Athira Rajeev
<atrajeev@linux.vnet.ibm.com> wrote:
> Hi Namhyung,
>
> I have a thought there. For the type and typeoff sort keys to work, we depend on Dwarf support in perf, right ?
> If the perf is built without dwarf support ( either due to older elfutils or missing libdw.h ) , find_data_type will return NULL and we will get “unknown” for Data Type and Data Type Offset in the result.

Yes, right.

>
> Can we add a pr_debug line in find_data_type (which is in else part for HAVE_DWARF_SUPPORT) so that user can understand if “unknown” is due to missing devel during the build ? Or may be restrict -s type,typeoff if dwarf support is missing ?

I think it's better to add a warning if DWARF is not supported.
Thanks for your review!

Namhyung