1 /* DW_EH_PE_* support for libdw unwinder. 2 Copyright (C) 2009-2010 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 #ifndef _ENCODED_VALUE_H 51 #define _ENCODED_VALUE_H 1 52 53 #include <dwarf.h> 54 #include <stdlib.h> 55 #include "libdwP.h" 56 57 58 static size_t __attribute__ ((unused)) 59 encoded_value_size (const Elf_Data *data, const unsigned char e_ident[], 60 uint8_t encoding, const uint8_t *p) 61 { 62 if (encoding == DW_EH_PE_omit) 63 return 0; 64 65 switch (encoding & 0x07) 66 { 67 case DW_EH_PE_udata2: 68 return 2; 69 case DW_EH_PE_udata4: 70 return 4; 71 case DW_EH_PE_udata8: 72 return 8; 73 74 case DW_EH_PE_absptr: 75 return e_ident[EI_CLASS] == ELFCLASS32 ? 4 : 8; 76 77 case DW_EH_PE_uleb128: 78 if (p != NULL) 79 { 80 const uint8_t *end = p; 81 while (end < (uint8_t *) data->d_buf + data->d_size) 82 if (*end++ & 0x80u) 83 return end - p; 84 } 85 86 default: 87 abort (); 88 return 0; 89 } 90 } 91 92 static inline int __attribute__ ((unused)) 93 __libdw_cfi_read_address_inc (const Dwarf_CFI *cache, 94 const unsigned char **addrp, 95 int width, Dwarf_Addr *ret) 96 { 97 width = width ?: cache->e_ident[EI_CLASS] == ELFCLASS32 ? 4 : 8; 98 99 if (cache->dbg != NULL) 100 return __libdw_read_address_inc (cache->dbg, IDX_debug_frame, 101 addrp, width, ret); 102 103 /* Only .debug_frame might have relocation to consider. 104 Read plain values from .eh_frame data. */ 105 106 if (width == 4) 107 *ret = read_4ubyte_unaligned_inc (cache, *addrp); 108 else 109 *ret = read_8ubyte_unaligned_inc (cache, *addrp); 110 return 0; 111 } 112 113 static bool __attribute__ ((unused)) 114 read_encoded_value (const Dwarf_CFI *cache, uint8_t encoding, const uint8_t **p, 115 Dwarf_Addr *result) 116 { 117 *result = 0; 118 switch (encoding & 0x70) 119 { 120 case DW_EH_PE_absptr: 121 break; 122 case DW_EH_PE_pcrel: 123 *result = (cache->frame_vaddr 124 + (*p - (const uint8_t *) cache->data->d.d_buf)); 125 break; 126 case DW_EH_PE_textrel: 127 // ia64: segrel 128 *result = cache->textrel; 129 break; 130 case DW_EH_PE_datarel: 131 // i386: GOTOFF 132 // ia64: gprel 133 *result = cache->datarel; 134 break; 135 case DW_EH_PE_funcrel: /* XXX */ 136 break; 137 case DW_EH_PE_aligned: 138 { 139 const size_t size = encoded_value_size (&cache->data->d, cache->e_ident, 140 encoding, *p); 141 size_t align = ((cache->frame_vaddr 142 + (*p - (const uint8_t *) cache->data->d.d_buf)) 143 & (size - 1)); 144 if (align != 0) 145 *p += size - align; 146 break; 147 } 148 149 default: 150 abort (); 151 } 152 153 Dwarf_Addr value; 154 switch (encoding & 0x0f) 155 { 156 case DW_EH_PE_udata2: 157 value = read_2ubyte_unaligned_inc (cache, *p); 158 break; 159 160 case DW_EH_PE_sdata2: 161 value = read_2sbyte_unaligned_inc (cache, *p); 162 break; 163 164 case DW_EH_PE_udata4: 165 if (__libdw_cfi_read_address_inc (cache, p, 4, &value)) 166 return true; 167 break; 168 169 case DW_EH_PE_sdata4: 170 if (__libdw_cfi_read_address_inc (cache, p, 4, &value)) 171 return true; 172 value = (Dwarf_Sword) (Elf32_Sword) value; /* Sign-extend. */ 173 break; 174 175 case DW_EH_PE_udata8: 176 case DW_EH_PE_sdata8: 177 if (__libdw_cfi_read_address_inc (cache, p, 8, &value)) 178 return true; 179 break; 180 181 case DW_EH_PE_absptr: 182 if (__libdw_cfi_read_address_inc (cache, p, 0, &value)) 183 return true; 184 break; 185 186 case DW_EH_PE_uleb128: 187 get_uleb128 (value, *p); 188 break; 189 190 case DW_EH_PE_sleb128: 191 get_sleb128 (value, *p); 192 break; 193 194 default: 195 abort (); 196 } 197 198 *result += value; 199 200 if (encoding & DW_EH_PE_indirect) 201 { 202 if (unlikely (*result < cache->frame_vaddr)) 203 return true; 204 *result -= cache->frame_vaddr; 205 if (unlikely (*result > (cache->data->d.d_size 206 - encoded_value_size (NULL, cache->e_ident, 207 DW_EH_PE_absptr, NULL)))) 208 return true; 209 const uint8_t *ptr = cache->data->d.d_buf + *result; 210 return __libdw_cfi_read_address_inc (cache, &ptr, 0, result); 211 } 212 213 return false; 214 } 215 216 #endif /* encoded-value.h */ 217
