Re: Patch to handle DWARF2 DW_FORM_indirect

Keith.Walker
2001-11-27T04:01:00Z

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

Updated to matched the latest file from CVS which has Jakub's patch applied

>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?

It will now output "unexpected attribute form: DW_FORM_indirect".

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

Here is the updated patch for gdb:

ChangeLog:

2001-11-27 Keith Walker <keith.walker@arm.com>
* dwarf2read.c (read_attribute_value): New function to handle
DW_FORM_indirect
(read_attribute): uses read_attribute_value

Index: dwarf2read.c
===================================================================
RCS file: /cvs/src/src/gdb/dwarf2read.c,v
retrieving revision 1.35
diff -u -r1.35 dwarf2read.c
--- dwarf2read.c 2001/11/17 00:08:10 1.35
+++ dwarf2read.c 2001/11/27 11:40:43
@@ -605,6 +605,9 @@
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 *);
@@ -3360,19 +3363,18 @@
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:
@@ -3469,13 +3471,28 @@
info_ptr += bytes_read;
break;
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;
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
@@ -5624,8 +5641,12 @@
fprintf (stderr, "flag: TRUE");
else
fprintf (stderr, "flag: FALSE");
+ break;
+ case DW_FORM_indirect:
+ /* the reader will have reduced the indirect form to
+ the "base form" so this form should not occur */
+ fprintf (stderr, "unexpected attribute form: DW_FORM_indirect");
break;
- case DW_FORM_indirect: /* we do not handle indirect yet */
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