Re: [PATCH] perf annotate: Add more x86 mov instruction cases

[Namhyung Kim]

Hi Ian,

On Thu, Sep 7, 2023 at 11:24 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> On Thu, Sep 7, 2023 at 10:22 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> >
> > Instructions with sign- and zero- extention like movsbl and movzwq were
> > not handled properly.  As it can check different size suffix (-b, -w, -l
> > or -q) we can omit that and add the common parts even though some
> > combinations are not possible.
> >
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> >  tools/perf/arch/x86/annotate/instructions.c | 9 ++++++---
> >  1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/arch/x86/annotate/instructions.c b/tools/perf/arch/x86/annotate/instructions.c
> > index 5f4ac4fc7fcf..5cdf457f5cbe 100644
> > --- a/tools/perf/arch/x86/annotate/instructions.c
> > +++ b/tools/perf/arch/x86/annotate/instructions.c
> > @@ -74,12 +74,15 @@ static struct ins x86__instructions[] = {
> >         { .name = "movdqa",     .ops = &mov_ops,  },
> >         { .name = "movdqu",     .ops = &mov_ops,  },
> >         { .name = "movsd",      .ops = &mov_ops,  },
> > -       { .name = "movslq",     .ops = &mov_ops,  },
> >         { .name = "movss",      .ops = &mov_ops,  },
> > +       { .name = "movsb",      .ops = &mov_ops,  },
> > +       { .name = "movsw",      .ops = &mov_ops,  },
> > +       { .name = "movsl",      .ops = &mov_ops,  },
>
> In Intel's manual some of these names are "Move Data From String to
> String" operations, movsb and movsw in particular. These instructions
> can be used to make simple memcpy loops. Could it be the past omission
> was deliberate due to the different way the addressing works in the
> instructions?

I don't know but in terms of instruction parsing, they are the same
"MOVE" with two operands.  I'm not aware of anything in perf with
the operands of these instructions.  So I guess it'd be fine to add
these instructions even if they have different underlying behaviors.

Thanks,
Namhyung