Re: [PATCH 08/48] perf dwarf-aux: Factor out __die_get_typename()

[Namhyung Kim]

Hi Masami,

On Sun, Nov 5, 2023 at 1:07 AM Masami Hiramatsu <mhiramat@xxxxxxxxxx> wrote:
>
> On Wed, 11 Oct 2023 20:50:31 -0700
> Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> > The __die_get_typename() is to get the name of the given DIE in C-style
> > type name.  The difference from the die_get_typename() is that it does
> > not retrieve the DW_AT_type and use the given DIE directly.  This will
> > be used when users know the type DIE already.
>
> Hmm, I would rather like to have another name for this function.
> What about 'die_get_typename_from_type()' ?

Ok.

> >
> > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
> > ---
> >  tools/perf/util/dwarf-aux.c | 38 ++++++++++++++++++++++++++-----------
> >  tools/perf/util/dwarf-aux.h |  3 +++
> >  2 files changed, 30 insertions(+), 11 deletions(-)
> >
> > diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
> > index 652e6e7368a2..5bb05c84d249 100644
> > --- a/tools/perf/util/dwarf-aux.c
> > +++ b/tools/perf/util/dwarf-aux.c
> > @@ -1051,32 +1051,28 @@ Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
> >  }
> >
> >  /**
> > - * die_get_typename - Get the name of given variable DIE
> > - * @vr_die: a variable DIE
> > + * __die_get_typename - Get the name of given type DIE
> > + * @type: a type DIE
> >   * @buf: a strbuf for result type name
> >   *
> > - * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
> > + * Get the name of @type_die and stores it to @buf. Return 0 if succeeded.
> >   * and Return -ENOENT if failed to find type name.
> >   * Note that the result will stores typedef name if possible, and stores
> >   * "*(function_type)" if the type is a function pointer.
> >   */
> > -int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
> > +int __die_get_typename(Dwarf_Die *type, struct strbuf *buf)
>
> Could you use 'type_die' instead of 'type' if it is exposed?

Will change, thanks for your review!
Namhyung


> >  {
> > -     Dwarf_Die type;
> >       int tag, ret;
> >       const char *tmp = "";
> >
> > -     if (__die_get_real_type(vr_die, &type) == NULL)
> > -             return -ENOENT;
> > -
> > -     tag = dwarf_tag(&type);
> > +     tag = dwarf_tag(type);
> >       if (tag == DW_TAG_array_type || tag == DW_TAG_pointer_type)
> >               tmp = "*";
> >       else if (tag == DW_TAG_subroutine_type) {
> >               /* Function pointer */
> >               return strbuf_add(buf, "(function_type)", 15);
> >       } else {
> > -             const char *name = dwarf_diename(&type);
> > +             const char *name = dwarf_diename(type);
> >
> >               if (tag == DW_TAG_union_type)
> >                       tmp = "union ";
> > @@ -1089,7 +1085,7 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
> >               /* Write a base name */
> >               return strbuf_addf(buf, "%s%s", tmp, name ?: "");
> >       }
> > -     ret = die_get_typename(&type, buf);
> > +     ret = die_get_typename(type, buf);
> >       if (ret < 0) {
> >               /* void pointer has no type attribute */
> >               if (tag == DW_TAG_pointer_type && ret == -ENOENT)
> > @@ -1100,6 +1096,26 @@ int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
> >       return strbuf_addstr(buf, tmp);
> >  }
> >
> > +/**
> > + * die_get_typename - Get the name of given variable DIE
> > + * @vr_die: a variable DIE
> > + * @buf: a strbuf for result type name
> > + *
> > + * Get the name of @vr_die and stores it to @buf. Return 0 if succeeded.
> > + * and Return -ENOENT if failed to find type name.
> > + * Note that the result will stores typedef name if possible, and stores
> > + * "*(function_type)" if the type is a function pointer.
> > + */
> > +int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf)
> > +{
> > +     Dwarf_Die type;
> > +
> > +     if (__die_get_real_type(vr_die, &type) == NULL)
> > +             return -ENOENT;
> > +
> > +     return __die_get_typename(&type, buf);
> > +}
> > +
> >  /**
> >   * die_get_varname - Get the name and type of given variable DIE
> >   * @vr_die: a variable DIE
> > diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
> > index b6f430730bd1..574405c57d3b 100644
> > --- a/tools/perf/util/dwarf-aux.h
> > +++ b/tools/perf/util/dwarf-aux.h
> > @@ -116,6 +116,9 @@ Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
> >  Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
> >                          Dwarf_Die *die_mem);
> >
> > +/* Get the name of given type DIE */
> > +int __die_get_typename(Dwarf_Die *type, struct strbuf *buf);
> > +
> >  /* Get the name of given variable DIE */
> >  int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
> >
> > --
> > 2.42.0.655.g421f12c284-goog
> >
>
>
> --
> Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>