linux-kernel - Re: [PATCH 1/2] perf annotate: Handle x86 instruction suffix generally

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Message-ID: <CAM9d7cif9PPBWPEZx6MA6E4FHaAQLbi-0pEGwLrtLxiEASog9Q@mail.gmail.com>
Date:   Wed, 24 May 2023 09:10:47 -0700
From:   Namhyung Kim <namhyung@...nel.org>
To:     Adrian Hunter <adrian.hunter@...el.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [PATCH 1/2] perf annotate: Handle x86 instruction suffix generally

Hi Adrian,

On Tue, May 23, 2023 at 11:11 PM Adrian Hunter <adrian.hunter@...el.com> wrote:
>
> On 24/05/23 08:28, Namhyung Kim wrote:
> > Most of x86 instructions can have size suffix like b, w, l or q.
>
> (AT&T mnemonics)

Right, will update.

>
> > Instead of adding all these instructions in the table, we can handle
> > them in a general way.  For example, it can try to find an instruction
> > as is.  If not found, it'd try again without the suffix if it's one of
> > the allowed suffixes.
>
> I guess it might be possible that xyz is in the table but xyz<suffix>
> is a completely different instruction?

Then xyz<suffix> should be in the table too.  The match without
suffix is a fallback so it should find the correct instruction first.

Thanks,
Namhyung


>
> >
> > Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> > ---
> >  tools/perf/util/annotate.c | 22 ++++++++++++++++++++++
> >  1 file changed, 22 insertions(+)
> >
> > diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> > index b708bbc49c9e..7f05f2a2aa83 100644
> > --- a/tools/perf/util/annotate.c
> > +++ b/tools/perf/util/annotate.c
> > @@ -70,6 +70,7 @@ struct arch {
> >       struct ins_ops  *(*associate_instruction_ops)(struct arch *arch, const char *name);
> >       bool            sorted_instructions;
> >       bool            initialized;
> > +     const char      *insn_suffix;
> >       void            *priv;
> >       unsigned int    model;
> >       unsigned int    family;
> > @@ -179,6 +180,7 @@ static struct arch architectures[] = {
> >               .init = x86__annotate_init,
> >               .instructions = x86__instructions,
> >               .nr_instructions = ARRAY_SIZE(x86__instructions),
> > +             .insn_suffix = "bwlq",
> >               .objdump =  {
> >                       .comment_char = '#',
> >               },
> > @@ -720,6 +722,26 @@ static struct ins_ops *__ins__find(struct arch *arch, const char *name)
> >       }
> >
> >       ins = bsearch(name, arch->instructions, nmemb, sizeof(struct ins), ins__key_cmp);
> > +     if (ins)
> > +             return ins->ops;
> > +
> > +     if (arch->insn_suffix) {
> > +             char tmp[32];
> > +             char suffix;
> > +             size_t len = strlen(name);
> > +
> > +             if (len == 0 || len >= sizeof(tmp))
> > +                     return NULL;
> > +
> > +             suffix = name[len - 1];
> > +             if (strchr(arch->insn_suffix, suffix) == NULL)
> > +                     return NULL;
> > +
> > +             strcpy(tmp, name);
> > +             tmp[len - 1] = '\0'; /* remove the suffix and check again */
> > +
> > +             ins = bsearch(tmp, arch->instructions, nmemb, sizeof(struct ins), ins__key_cmp);
> > +     }
> >       return ins ? ins->ops : NULL;
> >  }
> >
>