1/* Return associated attribute for DW_OP_GNU_implicit_pointer.
2   Copyright (C) 2010 Red Hat, Inc.
3   This file is part of elfutils.
4
5   This file is free software; you can redistribute it and/or modify
6   it under the terms of either
7
8     * the GNU Lesser General Public License as published by the Free
9       Software Foundation; either version 3 of the License, or (at
10       your option) any later version
11
12   or
13
14     * the GNU General Public License as published by the Free
15       Software Foundation; either version 2 of the License, or (at
16       your option) any later version
17
18   or both in parallel, as here.
19
20   elfutils is distributed in the hope that it will be useful, but
21   WITHOUT ANY WARRANTY; without even the implied warranty of
22   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
23   General Public License for more details.
24
25   You should have received copies of the GNU General Public License and
26   the GNU Lesser General Public License along with this program.  If
27   not, see <http://www.gnu.org/licenses/>.  */
28
29#ifdef HAVE_CONFIG_H
30# include <config.h>
31#endif
32
33#include "libdwP.h"
34#include <dwarf.h>
35
36
37static unsigned char empty_exprloc = 0;
38static Dwarf_CU empty_cu = { .startp = &empty_exprloc,
39			     .endp = &empty_exprloc + 1 };
40
41void
42internal_function
43__libdw_empty_loc_attr (Dwarf_Attribute *attr)
44{
45  attr->code = DW_AT_location;
46  attr->form = DW_FORM_exprloc;
47  attr->valp = &empty_exprloc;
48  attr->cu = &empty_cu;
49}
50
51int
52dwarf_getlocation_implicit_pointer (attr, op, result)
53     Dwarf_Attribute *attr;
54     const Dwarf_Op *op;
55     Dwarf_Attribute *result;
56{
57  if (attr == NULL)
58    return -1;
59
60  if (unlikely (op->atom != DW_OP_GNU_implicit_pointer))
61    {
62      __libdw_seterrno (DWARF_E_INVALID_ACCESS);
63      return -1;
64    }
65
66  Dwarf_Die die;
67  if (__libdw_offdie (attr->cu->dbg, op->number, &die,
68		      attr->cu->type_offset != 0) == NULL)
69    return -1;
70
71  if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL
72      && INTUSE(dwarf_attr) (&die, DW_AT_const_value, result) == NULL)
73    {
74      __libdw_empty_loc_attr (result);
75      return 0;
76    }
77
78  return 0;
79}
80