1 /* Get abbreviation at given offset. 2 Copyright (C) 2003, 2004, 2005, 2006 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 Written by Ulrich Drepper <drepper (at) redhat.com>, 2003. 5 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. 9 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. 14 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. 18 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. 42 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>. */ 50 51 #ifdef HAVE_CONFIG_H 52 # include <config.h> 53 #endif 54 55 #include <assert.h> 56 #include <dwarf.h> 57 #include "libdwP.h" 58 59 60 Dwarf_Abbrev * 61 internal_function 62 __libdw_getabbrev (dbg, cu, offset, lengthp, result) 63 Dwarf *dbg; 64 struct Dwarf_CU *cu; 65 Dwarf_Off offset; 66 size_t *lengthp; 67 Dwarf_Abbrev *result; 68 { 69 /* Don't fail if there is not .debug_abbrev section. */ 70 if (dbg->sectiondata[IDX_debug_abbrev] == NULL) 71 return NULL; 72 73 if (offset >= dbg->sectiondata[IDX_debug_abbrev]->d_size) 74 { 75 __libdw_seterrno (DWARF_E_INVALID_OFFSET); 76 return NULL; 77 } 78 79 const unsigned char *abbrevp 80 = (unsigned char *) dbg->sectiondata[IDX_debug_abbrev]->d_buf + offset; 81 82 if (*abbrevp == '\0') 83 /* We are past the last entry. */ 84 return DWARF_END_ABBREV; 85 86 /* 7.5.3 Abbreviations Tables 87 88 [...] Each declaration begins with an unsigned LEB128 number 89 representing the abbreviation code itself. [...] The 90 abbreviation code is followed by another unsigned LEB128 91 number that encodes the entry's tag. [...] 92 93 [...] Following the tag encoding is a 1-byte value that 94 determines whether a debugging information entry using this 95 abbreviation has child entries or not. [...] 96 97 [...] Finally, the child encoding is followed by a series of 98 attribute specifications. Each attribute specification 99 consists of two parts. The first part is an unsigned LEB128 100 number representing the attribute's name. The second part is 101 an unsigned LEB128 number representing the attribute's form. */ 102 const unsigned char *start_abbrevp = abbrevp; 103 unsigned int code; 104 get_uleb128 (code, abbrevp); 105 106 /* Check whether this code is already in the hash table. */ 107 bool foundit = false; 108 Dwarf_Abbrev *abb = NULL; 109 if (cu == NULL 110 || (abb = Dwarf_Abbrev_Hash_find (&cu->abbrev_hash, code, NULL)) == NULL) 111 { 112 if (result == NULL) 113 abb = libdw_typed_alloc (dbg, Dwarf_Abbrev); 114 else 115 abb = result; 116 } 117 else 118 { 119 foundit = true; 120 121 assert (abb->offset == offset); 122 123 /* If the caller doesn't need the length we are done. */ 124 if (lengthp == NULL) 125 goto out; 126 } 127 128 /* If there is already a value in the hash table we are going to 129 overwrite its content. This must not be a problem, since the 130 content better be the same. */ 131 abb->code = code; 132 get_uleb128 (abb->tag, abbrevp); 133 abb->has_children = *abbrevp++ == DW_CHILDREN_yes; 134 abb->attrp = (unsigned char *) abbrevp; 135 abb->offset = offset; 136 137 /* Skip over all the attributes and count them while doing so. */ 138 abb->attrcnt = 0; 139 unsigned int attrname; 140 unsigned int attrform; 141 do 142 { 143 get_uleb128 (attrname, abbrevp); 144 get_uleb128 (attrform, abbrevp); 145 } 146 while (attrname != 0 && attrform != 0 && ++abb->attrcnt); 147 148 /* Return the length to the caller if she asked for it. */ 149 if (lengthp != NULL) 150 *lengthp = abbrevp - start_abbrevp; 151 152 /* Add the entry to the hash table. */ 153 if (cu != NULL && ! foundit) 154 (void) Dwarf_Abbrev_Hash_insert (&cu->abbrev_hash, abb->code, abb); 155 156 out: 157 return abb; 158 } 159 160 161 Dwarf_Abbrev * 162 dwarf_getabbrev (die, offset, lengthp) 163 Dwarf_Die *die; 164 Dwarf_Off offset; 165 size_t *lengthp; 166 { 167 return __libdw_getabbrev (die->cu->dbg, die->cu, 168 die->cu->orig_abbrev_offset + offset, lengthp, 169 NULL); 170 } 171
