1 /* Compute size of an aggregate type from DWARF. 2 Copyright (C) 2010, 2014 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 <dwarf.h> 34 #include "libdwP.h" 35 36 37 static Dwarf_Die * 38 get_type (Dwarf_Die *die, Dwarf_Attribute *attr_mem, Dwarf_Die *type_mem) 39 { 40 Dwarf_Die *type = INTUSE(dwarf_formref_die) 41 (INTUSE(dwarf_attr_integrate) (die, DW_AT_type, attr_mem), type_mem); 42 43 if (INTUSE(dwarf_peel_type) (type, type) != 0) 44 return NULL; 45 46 return type; 47 } 48 49 static int 50 array_size (Dwarf_Die *die, Dwarf_Word *size, 51 Dwarf_Attribute *attr_mem, Dwarf_Die *type_mem) 52 { 53 Dwarf_Word eltsize; 54 if (INTUSE(dwarf_aggregate_size) (get_type (die, attr_mem, type_mem), 55 &eltsize) != 0) 56 return -1; 57 58 /* An array can have DW_TAG_subrange_type or DW_TAG_enumeration_type 59 children instead that give the size of each dimension. */ 60 61 Dwarf_Die child; 62 if (INTUSE(dwarf_child) (die, &child) != 0) 63 return -1; 64 65 bool any = false; 66 Dwarf_Word total = 0; 67 do 68 { 69 Dwarf_Word count; 70 switch (INTUSE(dwarf_tag) (&child)) 71 { 72 case DW_TAG_subrange_type: 73 /* This has either DW_AT_count or DW_AT_upper_bound. */ 74 if (INTUSE(dwarf_attr_integrate) (&child, DW_AT_count, 75 attr_mem) != NULL) 76 { 77 if (INTUSE(dwarf_formudata) (attr_mem, &count) != 0) 78 return -1; 79 } 80 else 81 { 82 Dwarf_Sword upper; 83 Dwarf_Sword lower; 84 if (INTUSE(dwarf_formsdata) (INTUSE(dwarf_attr_integrate) 85 (&child, DW_AT_upper_bound, 86 attr_mem), &upper) != 0) 87 return -1; 88 89 /* Having DW_AT_lower_bound is optional. */ 90 if (INTUSE(dwarf_attr_integrate) (&child, DW_AT_lower_bound, 91 attr_mem) != NULL) 92 { 93 if (INTUSE(dwarf_formsdata) (attr_mem, &lower) != 0) 94 return -1; 95 } 96 else 97 { 98 /* Determine default lower bound from language, 99 as per "4.12 Subrange Type Entries". */ 100 Dwarf_Die cu = CUDIE (die->cu); 101 switch (INTUSE(dwarf_srclang) (&cu)) 102 { 103 case DW_LANG_C: 104 case DW_LANG_C89: 105 case DW_LANG_C99: 106 case DW_LANG_C11: 107 case DW_LANG_C_plus_plus: 108 case DW_LANG_C_plus_plus_11: 109 case DW_LANG_C_plus_plus_14: 110 case DW_LANG_ObjC: 111 case DW_LANG_ObjC_plus_plus: 112 case DW_LANG_Java: 113 case DW_LANG_D: 114 case DW_LANG_UPC: 115 case DW_LANG_Go: 116 lower = 0; 117 break; 118 119 case DW_LANG_Ada83: 120 case DW_LANG_Ada95: 121 case DW_LANG_Cobol74: 122 case DW_LANG_Cobol85: 123 case DW_LANG_Fortran77: 124 case DW_LANG_Fortran90: 125 case DW_LANG_Fortran95: 126 case DW_LANG_Pascal83: 127 case DW_LANG_Modula2: 128 case DW_LANG_PL1: 129 lower = 1; 130 break; 131 132 default: 133 return -1; 134 } 135 } 136 if (unlikely (lower > upper)) 137 return -1; 138 count = upper - lower + 1; 139 } 140 break; 141 142 case DW_TAG_enumeration_type: 143 /* We have to find the DW_TAG_enumerator child with the 144 highest value to know the array's element count. */ 145 count = 0; 146 Dwarf_Die enum_child; 147 int has_children = INTUSE(dwarf_child) (die, &enum_child); 148 if (has_children < 0) 149 return -1; 150 if (has_children > 0) 151 do 152 if (INTUSE(dwarf_tag) (&enum_child) == DW_TAG_enumerator) 153 { 154 Dwarf_Word value; 155 if (INTUSE(dwarf_formudata) (INTUSE(dwarf_attr_integrate) 156 (&enum_child, DW_AT_const_value, 157 attr_mem), &value) != 0) 158 return -1; 159 if (value >= count) 160 count = value + 1; 161 } 162 while (INTUSE(dwarf_siblingof) (&enum_child, &enum_child) > 0); 163 break; 164 165 default: 166 continue; 167 } 168 169 /* This is a subrange_type or enumeration_type and we've set COUNT. 170 Now determine the stride for this array dimension. */ 171 Dwarf_Word stride = eltsize; 172 if (INTUSE(dwarf_attr_integrate) (&child, DW_AT_byte_stride, 173 attr_mem) != NULL) 174 { 175 if (INTUSE(dwarf_formudata) (attr_mem, &stride) != 0) 176 return -1; 177 } 178 else if (INTUSE(dwarf_attr_integrate) (&child, DW_AT_bit_stride, 179 attr_mem) != NULL) 180 { 181 if (INTUSE(dwarf_formudata) (attr_mem, &stride) != 0) 182 return -1; 183 if (stride % 8) /* XXX maybe compute in bits? */ 184 return -1; 185 stride /= 8; 186 } 187 188 any = true; 189 total += stride * count; 190 } 191 while (INTUSE(dwarf_siblingof) (&child, &child) == 0); 192 193 if (!any) 194 return -1; 195 196 *size = total; 197 return 0; 198 } 199 200 static int 201 aggregate_size (Dwarf_Die *die, Dwarf_Word *size, Dwarf_Die *type_mem) 202 { 203 Dwarf_Attribute attr_mem; 204 205 if (INTUSE(dwarf_attr_integrate) (die, DW_AT_byte_size, &attr_mem) != NULL) 206 return INTUSE(dwarf_formudata) (&attr_mem, size); 207 208 switch (INTUSE(dwarf_tag) (die)) 209 { 210 case DW_TAG_subrange_type: 211 return aggregate_size (get_type (die, &attr_mem, type_mem), 212 size, type_mem); /* Tail call. */ 213 214 case DW_TAG_array_type: 215 return array_size (die, size, &attr_mem, type_mem); 216 217 /* Assume references and pointers have pointer size if not given an 218 explicit DW_AT_byte_size. */ 219 case DW_TAG_pointer_type: 220 case DW_TAG_reference_type: 221 case DW_TAG_rvalue_reference_type: 222 *size = die->cu->address_size; 223 return 0; 224 } 225 226 /* Most types must give their size directly. */ 227 return -1; 228 } 229 230 int 231 dwarf_aggregate_size (die, size) 232 Dwarf_Die *die; 233 Dwarf_Word *size; 234 { 235 Dwarf_Die type_mem; 236 237 if (INTUSE (dwarf_peel_type) (die, die) != 0) 238 return -1; 239 240 return aggregate_size (die, size, &type_mem); 241 } 242 INTDEF (dwarf_aggregate_size) 243 OLD_VERSION (dwarf_aggregate_size, ELFUTILS_0.144) 244 NEW_VERSION (dwarf_aggregate_size, ELFUTILS_0.161) 245
