Re: [PATCH v3] perf: fix the probe finder location (.dwo files)

Arnaldo Carvalho de Melo
2022-10-17T12:38:02Z

Em Wed, Oct 05, 2022 at 08:47:02AM -0400, Henry Castro escreveu:
> If the file object is compiled using -gsplit-dwarf,
> the probe finder location will fail.
>
> Signed-off-by: Henry Castro <hcvcastro@gmail.com>
> ---
>
> > Nit, I think we use _ELFUTILS_PREREQ(0, 171).
> Thank you

Masami, are you ok with this?

Namyung, how about you?

Thanks,

- Arnaldo

> > How about making it a separate function with 2 versions
> > depending on the elfutils? Then you can have the variables
> > only if they are used.
>
> > Something like get_source_from_debuginfod() in the same
> > file.
>
> Sounds good, but I prefer simplicity in the patch =),
> what do you think about
> {
> Dwarf_Die cudie, subdie;
> if (dwarf_cu_info() ..)
> ..
> }
>
> to resolve unused variable?
> }
>
>
> tools/perf/util/probe-finder.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
>
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 50d861a80f57..5f6781e712db 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1200,6 +1200,20 @@ static int debuginfo__find_probe_location(struct debuginfo *dbg,
> continue;
> }
>
> +#if _ELFUTILS_PREREQ(0, 171)
> + {
> + uint8_t unit_type;
> + Dwarf_Die cudie, subdie;
> +
> + /* Check separate debug information file. */
> + if (dwarf_cu_info(pf->cu_die.cu, NULL,
> + &unit_type, &cudie,
> + &subdie, NULL,
> + NULL, NULL) == 0
> + && unit_type == DW_UT_skeleton)
> + pf->cu_die = subdie;
> + }
> +#endif
> /* Check if target file is included. */
> if (pp->file)
> pf->fname = cu_find_realpath(&pf->cu_die, pp->file);
> --
> 2.20.1

--

- Arnaldo