1/* Look up the DIE in a reference-form attribute. 2 Copyright (C) 2005-2010 Red Hat, Inc. 3 This file is part of Red Hat elfutils. 4 5 Red Hat elfutils is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by the 7 Free Software Foundation; version 2 of the License. 8 9 Red Hat elfutils is distributed in the hope that it will be useful, but 10 WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 General Public License for more details. 13 14 You should have received a copy of the GNU General Public License along 15 with Red Hat elfutils; if not, write to the Free Software Foundation, 16 Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. 17 18 In addition, as a special exception, Red Hat, Inc. gives You the 19 additional right to link the code of Red Hat elfutils with code licensed 20 under any Open Source Initiative certified open source license 21 (http://www.opensource.org/licenses/index.php) which requires the 22 distribution of source code with any binary distribution and to 23 distribute linked combinations of the two. Non-GPL Code permitted under 24 this exception must only link to the code of Red Hat elfutils through 25 those well defined interfaces identified in the file named EXCEPTION 26 found in the source code files (the "Approved Interfaces"). The files 27 of Non-GPL Code may instantiate templates or use macros or inline 28 functions from the Approved Interfaces without causing the resulting 29 work to be covered by the GNU General Public License. Only Red Hat, 30 Inc. may make changes or additions to the list of Approved Interfaces. 31 Red Hat's grant of this exception is conditioned upon your not adding 32 any new exceptions. If you wish to add a new Approved Interface or 33 exception, please contact Red Hat. You must obey the GNU General Public 34 License in all respects for all of the Red Hat elfutils code and other 35 code used in conjunction with Red Hat elfutils except the Non-GPL Code 36 covered by this exception. If you modify this file, you may extend this 37 exception to your version of the file, but you are not obligated to do 38 so. If you do not wish to provide this exception without modification, 39 you must delete this exception statement from your version and license 40 this file solely under the GPL without exception. 41 42 Red Hat elfutils is an included package of the Open Invention Network. 43 An included package of the Open Invention Network is a package for which 44 Open Invention Network licensees cross-license their patents. No patent 45 license is granted, either expressly or impliedly, by designation as an 46 included package. Should you wish to participate in the Open Invention 47 Network licensing program, please visit www.openinventionnetwork.com 48 <http://www.openinventionnetwork.com>. */ 49 50#ifdef HAVE_CONFIG_H 51# include <config.h> 52#endif 53 54#include <string.h> 55#include "libdwP.h" 56#include <dwarf.h> 57 58 59Dwarf_Die * 60dwarf_formref_die (attr, result) 61 Dwarf_Attribute *attr; 62 Dwarf_Die *result; 63{ 64 if (attr == NULL) 65 return NULL; 66 67 struct Dwarf_CU *cu = attr->cu; 68 69 Dwarf_Off offset; 70 if (attr->form == DW_FORM_ref_addr) 71 { 72 /* This has an absolute offset. */ 73 74 uint8_t ref_size = (cu->version == 2 75 ? cu->address_size 76 : cu->offset_size); 77 78 if (__libdw_read_offset (cu->dbg, IDX_debug_info, attr->valp, 79 ref_size, &offset, IDX_debug_info, 0)) 80 return NULL; 81 82 return INTUSE(dwarf_offdie) (cu->dbg, offset, result); 83 } 84 85 Elf_Data *data; 86 if (attr->form == DW_FORM_ref_sig8) 87 { 88 /* This doesn't have an offset, but instead a value we 89 have to match in the .debug_types type unit headers. */ 90 91 uint64_t sig = read_8ubyte_unaligned (cu->dbg, attr->valp); 92 cu = Dwarf_Sig8_Hash_find (&cu->dbg->sig8_hash, sig, NULL); 93 if (cu == NULL) 94 /* Not seen before. We have to scan through the type units. */ 95 do 96 { 97 cu = __libdw_intern_next_unit (attr->cu->dbg, true); 98 if (cu == NULL) 99 { 100 __libdw_seterrno (INTUSE(dwarf_errno) () 101 ?: DWARF_E_INVALID_REFERENCE); 102 return NULL; 103 } 104 Dwarf_Sig8_Hash_insert (&cu->dbg->sig8_hash, cu->type_sig8, cu); 105 } 106 while (cu->type_sig8 != sig); 107 108 data = cu->dbg->sectiondata[IDX_debug_types]; 109 offset = cu->type_offset; 110 } 111 else 112 { 113 /* Other forms produce an offset from the CU. */ 114 if (unlikely (__libdw_formref (attr, &offset) != 0)) 115 return NULL; 116 117 data = cu_data (cu); 118 } 119 120 if (unlikely (data->d_size - cu->start <= offset)) 121 { 122 __libdw_seterrno (DWARF_E_INVALID_DWARF); 123 return NULL; 124 } 125 126 memset (result, '\0', sizeof (Dwarf_Die)); 127 result->addr = (char *) data->d_buf + cu->start + offset; 128 result->cu = cu; 129 return result; 130} 131INTDEF (dwarf_formref_die) 132