Re: Patch to handle DWARF2 DW_FORM_indirect

[Elena Zannoni <ezannoni at cygnus dot com>]

Keith.Walker writes:
 > The DWARF2 specification allows the form of attributes to be described
 > "inline" with DW_FORM_indirect rather than the form being specified in a
 > separate abbreviation table.   The following patch adds support for
 > DW_FORM_indirect in BFD, binutils and GDB.
 >
 > If there are no objections, can this patch be approved and applied by the
 > GDB and binutils maintainers.
 >
 > Keith
 >

Your patch won't apply cleanly to gdb anymore, after Jakub's patch for
DW_FORM_strp was committed.

One comment: the 'case DW_FORM_indirect:' resulting in an error
message of unsupported attribute, is not correct anymore. Could you emit
a more pertinent message?

Other than that, it's fine. Could you repost an updated patch, just for
the record?

Thanks
Elena


 >
 > Index: gdb/ChangeLog
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/ChangeLog,v
 > retrieving revision 1.1758
 > diff -u -r1.1758 ChangeLog
 > --- ChangeLog    2001/11/13 03:10:33  1.1758
 > +++ ChangeLog    2001/11/13 17:24:15
 > @@ -1,3 +1,8 @@
 > +2001-11-13 Keith Walker <keith.walker@arm.com>
 > + * dwarf2read.c (read_attribute_value): New function to handle
 > + DW_FORM_indirect
 > + (read_attribute): uses read_attribute_value
 > +
 >  2001-11-10  Andrew Cagney  <ac131313@redhat.com>
 >
 >   * config/i960/tm-nindy960.h (REGISTER_CONVERTIBLE)
 >
 >
 > Index: gdb/dwarf2read.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/dwarf2read.c,v
 > retrieving revision 1.34
 > diff -u -r1.34 dwarf2read.c
 > --- dwarf2read.c 2001/11/12 20:36:55  1.34
 > +++ dwarf2read.c 2001/11/13 17:24:25
 > @@ -593,6 +593,9 @@
 >  static char *read_attribute (struct attribute *, struct attr_abbrev *,
 >                  bfd *, char *, const struct comp_unit_head *);
 >
 > +static char *read_attribute_value (struct attribute *, unsigned,
 > +                bfd *, char *, const struct comp_unit_head *);
 > +
 >  static unsigned int read_1_byte (bfd *, char *);
 >
 >  static int read_1_signed_byte (bfd *, char *);
 > @@ -3333,19 +3336,18 @@
 >    return info_ptr;
 >  }
 >
 > -/* Read an attribute described by an abbreviated attribute.  */
 > +/* Read an attribute value described by an attribute form.  */
 >
 >  static char *
 > -read_attribute (struct attribute *attr, struct attr_abbrev *abbrev,
 > +read_attribute_value (struct attribute *attr, unsigned form,
 >        bfd *abfd, char *info_ptr,
 >        const struct comp_unit_head *cu_header)
 >  {
 >    unsigned int bytes_read;
 >    struct dwarf_block *blk;
 >
 > -  attr->name = abbrev->name;
 > -  attr->form = abbrev->form;
 > -  switch (abbrev->form)
 > +  attr->form = form;
 > +  switch (form)
 >      {
 >      case DW_FORM_addr:
 >      case DW_FORM_ref_addr:
 > @@ -3436,15 +3438,30 @@
 >        DW_UNSND (attr) = read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
 >        info_ptr += bytes_read;
 >        break;
 > -    case DW_FORM_strp:
 >      case DW_FORM_indirect:
 > +      form = read_unsigned_leb128 (abfd, info_ptr, &bytes_read);
 > +      info_ptr += bytes_read;
 > +      info_ptr = read_attribute_value (attr, form, abfd, info_ptr,
cu_header);
 > +      break;
 > +    case DW_FORM_strp:
 >      default:
 >        error ("Dwarf Error: Cannot handle %s in DWARF reader.",
 > -      dwarf_form_name (abbrev->form));
 > +      dwarf_form_name (form));
 >      }
 >    return info_ptr;
 >  }
 >
 > +/* Read an attribute described by an abbreviated attribute.  */
 > +
 > +static char *
 > +read_attribute (struct attribute *attr, struct attr_abbrev *abbrev,
 > +      bfd *abfd, char *info_ptr,
 > +      const struct comp_unit_head *cu_header)
 > +{
 > +  attr->name = abbrev->name;
 > +  return read_attribute_value (attr, abbrev->form, abfd, info_ptr,
cu_header);
 > +}
 > +
 >  /* read dwarf information from a buffer */
 >
 >  static unsigned int
 > @@ -5602,7 +5619,9 @@
 >     break;
 >   case DW_FORM_strp:  /* we do not support separate string
 >                     section yet */
 > - case DW_FORM_indirect:   /* we do not handle indirect yet */
 > + case DW_FORM_indirect:   /* the reader will have reduced the indirect
 > +                                   form to the base type so this form
 > +                                   should not occur */
 >   default:
 >     fprintf (stderr, "unsupported attribute form: %d.",
 >           die->attrs[i].form);
 >
 >
 >
 > Keith Walker          keith.walker@arm.com           Tel:+44 (1628) 427732
 > ARM Ltd          http://www.arm.com