1 /* Advance to next CU header.
2 Copyright (C) 2002-2010 Red Hat, Inc.
3 This file is part of Red Hat elfutils.
4 Written by Ulrich Drepper <drepper@redhat.com>, 2002.
6 Red Hat elfutils is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by the
8 Free Software Foundation; version 2 of the License.
10 Red Hat elfutils is distributed in the hope that it will be useful, but
11 WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
15 You should have received a copy of the GNU General Public License along
16 with Red Hat elfutils; if not, write to the Free Software Foundation,
17 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA.
19 In addition, as a special exception, Red Hat, Inc. gives You the
20 additional right to link the code of Red Hat elfutils with code licensed
21 under any Open Source Initiative certified open source license
22 (http://www.opensource.org/licenses/index.php) which requires the
23 distribution of source code with any binary distribution and to
24 distribute linked combinations of the two. Non-GPL Code permitted under
25 this exception must only link to the code of Red Hat elfutils through
26 those well defined interfaces identified in the file named EXCEPTION
27 found in the source code files (the "Approved Interfaces"). The files
28 of Non-GPL Code may instantiate templates or use macros or inline
29 functions from the Approved Interfaces without causing the resulting
30 work to be covered by the GNU General Public License. Only Red Hat,
31 Inc. may make changes or additions to the list of Approved Interfaces.
32 Red Hat's grant of this exception is conditioned upon your not adding
33 any new exceptions. If you wish to add a new Approved Interface or
34 exception, please contact Red Hat. You must obey the GNU General Public
35 License in all respects for all of the Red Hat elfutils code and other
36 code used in conjunction with Red Hat elfutils except the Non-GPL Code
37 covered by this exception. If you modify this file, you may extend this
38 exception to your version of the file, but you are not obligated to do
39 so. If you do not wish to provide this exception without modification,
40 you must delete this exception statement from your version and license
41 this file solely under the GPL without exception.
43 Red Hat elfutils is an included package of the Open Invention Network.
44 An included package of the Open Invention Network is a package for which
45 Open Invention Network licensees cross-license their patents. No patent
46 license is granted, either expressly or impliedly, by designation as an
47 included package. Should you wish to participate in the Open Invention
48 Network licensing program, please visit www.openinventionnetwork.com
49 <http://www.openinventionnetwork.com>. */
60 dwarf_next_unit (dwarf, off, next_off, header_sizep, versionp, abbrev_offsetp,
61 address_sizep, offset_sizep, type_signaturep, type_offsetp)
67 Dwarf_Off *abbrev_offsetp;
68 uint8_t *address_sizep;
69 uint8_t *offset_sizep;
70 uint64_t *type_signaturep;
71 Dwarf_Off *type_offsetp;
73 const bool debug_types = type_signaturep != NULL;
74 const size_t sec_idx = debug_types ? IDX_debug_types : IDX_debug_info;
76 /* Maybe there has been an error before. */
80 /* If we reached the end before don't do anything. */
81 if (off == (Dwarf_Off) -1l
82 || unlikely (dwarf->sectiondata[sec_idx] == NULL)
83 /* Make sure there is enough space in the .debug_info section
84 for at least the initial word. We cannot test the rest since
85 we don't know yet whether this is a 64-bit object or not. */
86 || unlikely (off + 4 >= dwarf->sectiondata[sec_idx]->d_size))
88 *next_off = (Dwarf_Off) -1l;
92 /* This points into the .debug_info section to the beginning of the
94 const unsigned char *data = dwarf->sectiondata[sec_idx]->d_buf;
95 const unsigned char *bytes = data + off;
97 /* The format of the CU header is described in dwarf2p1 7.5.1:
99 1. A 4-byte or 12-byte unsigned integer representing the length
100 of the .debug_info contribution for that compilation unit, not
101 including the length field itself. In the 32-bit DWARF format,
102 this is a 4-byte unsigned integer (which must be less than
103 0xfffffff0); in the 64-bit DWARF format, this consists of the
104 4-byte value 0xffffffff followed by an 8-byte unsigned integer
105 that gives the actual length (see Section 7.2.2).
107 2. A 2-byte unsigned integer representing the version of the
108 DWARF information for that compilation unit. For DWARF Version
109 2.1, the value in this field is 2.
111 3. A 4-byte or 8-byte unsigned offset into the .debug_abbrev
112 section. This offset associates the compilation unit with a
113 particular set of debugging information entry abbreviations. In
114 the 32-bit DWARF format, this is a 4-byte unsigned length; in
115 the 64-bit DWARF format, this is an 8-byte unsigned length (see
118 4. A 1-byte unsigned integer representing the size in bytes of
119 an address on the target architecture. If the system uses
120 segmented addressing, this value represents the size of the
121 offset portion of an address. */
122 uint64_t length = read_4ubyte_unaligned_inc (dwarf, bytes);
123 size_t offset_size = 4;
124 /* Lengths of 0xfffffff0 - 0xffffffff are escape codes. Oxffffffff is
125 used to indicate that 64-bit dwarf information is being used, the
126 other values are currently reserved. */
127 if (length == DWARF3_LENGTH_64_BIT)
129 else if (unlikely (length >= DWARF3_LENGTH_MIN_ESCAPE_CODE
130 && length <= DWARF3_LENGTH_MAX_ESCAPE_CODE))
133 __libdw_seterrno (DWARF_E_INVALID_DWARF);
137 /* Now we know how large the header is. */
138 if (unlikely (DIE_OFFSET_FROM_CU_OFFSET (off, offset_size, debug_types)
139 >= dwarf->sectiondata[sec_idx]->d_size))
145 if (length == DWARF3_LENGTH_64_BIT)
146 /* This is a 64-bit DWARF format. */
147 length = read_8ubyte_unaligned_inc (dwarf, bytes);
149 /* Read the version stamp. Always a 16-bit value. */
150 uint_fast16_t version = read_2ubyte_unaligned_inc (dwarf, bytes);
152 /* Get offset in .debug_abbrev. Note that the size of the entry
153 depends on whether this is a 32-bit or 64-bit DWARF definition. */
154 uint64_t abbrev_offset;
155 if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size,
156 &abbrev_offset, IDX_debug_abbrev, 0))
159 /* The address size. Always an 8-bit value. */
160 uint8_t address_size = *bytes++;
164 uint64_t type_sig8 = read_8ubyte_unaligned_inc (dwarf, bytes);
166 Dwarf_Off type_offset;
167 if (__libdw_read_offset_inc (dwarf, sec_idx, &bytes, offset_size,
168 &type_offset, sec_idx, 0))
171 /* Validate that the TYPE_OFFSET points past the header. */
172 if (unlikely (type_offset < (size_t) (bytes - (data + off))))
175 *type_signaturep = type_sig8;
176 if (type_offsetp != NULL)
177 *type_offsetp = type_offset;
180 /* Store the header length. */
181 if (header_sizep != NULL)
182 *header_sizep = bytes - (data + off);
184 if (versionp != NULL)
187 if (abbrev_offsetp != NULL)
188 *abbrev_offsetp = abbrev_offset;
190 if (address_sizep != NULL)
191 *address_sizep = address_size;
193 /* Store the offset size. */
194 if (offset_sizep != NULL)
195 *offset_sizep = offset_size;
197 /* See definition of DIE_OFFSET_FROM_CU_OFFSET macro
198 for an explanation of the trick in this expression. */
199 *next_off = off + 2 * offset_size - 4 + length;
203 INTDEF(dwarf_next_unit)
206 dwarf_nextcu (dwarf, off, next_off, header_sizep, abbrev_offsetp,
207 address_sizep, offset_sizep)
211 size_t *header_sizep;
212 Dwarf_Off *abbrev_offsetp;
213 uint8_t *address_sizep;
214 uint8_t *offset_sizep;
216 return INTUSE(dwarf_next_unit) (dwarf, off, next_off, header_sizep, NULL,
217 abbrev_offsetp, address_sizep, offset_sizep,