linux-kernel - Re: [PATCH 3/3] perf disasm: Allow configuring what disassemblers to use

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Message-ID: <ZzXCiwDSqCMzaA17@google.com>
Date: Thu, 14 Nov 2024 10:27:39 +0100
From: "Steinar H. Gunderson" <sesse@...gle.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Ian Rogers <irogers@...gle.com>, Namhyung Kim <namhyung@...nel.org>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>, Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Clark Williams <williams@...hat.com>, linux-kernel@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Athira Rajeev <atrajeev@...ux.vnet.ibm.com>
Subject: Re: [PATCH 3/3] perf disasm: Allow configuring what disassemblers to
 use

On Wed, Nov 13, 2024 at 04:14:06PM -0300, Arnaldo Carvalho de Melo wrote:
> So, source code, automatically obtained from a debuginfod server and
> places where one can put a probe.

Mm, OK. Unfortunately I don't have any debuginfod stuff available on
this side, but I understand the desire.

I looked at the LLVM disassembler and it _does_ insert line numbers:

                  llvm_addr2line(filename, pc, &args->fileloc,
                                 (unsigned int *)&args->line_nr, false, NULL);

But this is maybe not enough? We don't have any machinery in perf to get
from the file + line number to the source ourselves? (What does capstone and
the embedded binutils disassembler do?)

> You can show just instructions or instructions + source code.
> 
> There were requests but no attempt that I know of of doing just source
> code.

TBH I'd love the latter, but I'm not going to sign up for doing it. :-)

/* Steinar */