1 /* Return associated attribute for DW_OP_GNU_implicit_pointer.
2 Copyright (C) 2010, 2017 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
37 static unsigned char empty_exprloc = 0;
38 static Dwarf_CU empty_cu = { .startp = &empty_exprloc,
39 .endp = &empty_exprloc + 1 };
40
41 void
42 internal_function
__libdw_empty_loc_attr(Dwarf_Attribute * attr)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
51 int
dwarf_getlocation_implicit_pointer(Dwarf_Attribute * attr,const Dwarf_Op * op,Dwarf_Attribute * result)52 dwarf_getlocation_implicit_pointer (Dwarf_Attribute *attr, const Dwarf_Op *op,
53 Dwarf_Attribute *result)
54 {
55 if (attr == NULL)
56 return -1;
57
58 if (unlikely (op->atom != DW_OP_implicit_pointer
59 && op->atom != DW_OP_GNU_implicit_pointer))
60 {
61 __libdw_seterrno (DWARF_E_INVALID_ACCESS);
62 return -1;
63 }
64
65 Dwarf_Die die;
66 if (__libdw_offdie (attr->cu->dbg, op->number, &die,
67 ISV4TU(attr->cu)) == NULL)
68 return -1;
69
70 if (INTUSE(dwarf_attr) (&die, DW_AT_location, result) == NULL
71 && INTUSE(dwarf_attr) (&die, DW_AT_const_value, result) == NULL)
72 {
73 __libdw_empty_loc_attr (result);
74 return 0;
75 }
76
77 return 0;
78 }
79