| 1 | /* Find a variable's value in memory, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986-2015 Free Software Foundation, Inc. |
| 4 | |
| 5 | This file is part of GDB. |
| 6 | |
| 7 | This program is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by |
| 9 | the Free Software Foundation; either version 3 of the License, or |
| 10 | (at your option) any later version. |
| 11 | |
| 12 | This program is distributed in the hope that it will be useful, |
| 13 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | GNU General Public License for more details. |
| 16 | |
| 17 | You should have received a copy of the GNU General Public License |
| 18 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 19 | |
| 20 | #include "defs.h" |
| 21 | #include "symtab.h" |
| 22 | #include "gdbtypes.h" |
| 23 | #include "frame.h" |
| 24 | #include "value.h" |
| 25 | #include "gdbcore.h" |
| 26 | #include "inferior.h" |
| 27 | #include "target.h" |
| 28 | #include "floatformat.h" |
| 29 | #include "symfile.h" /* for overlay functions */ |
| 30 | #include "regcache.h" |
| 31 | #include "user-regs.h" |
| 32 | #include "block.h" |
| 33 | #include "objfiles.h" |
| 34 | #include "language.h" |
| 35 | |
| 36 | /* Basic byte-swapping routines. All 'extract' functions return a |
| 37 | host-format integer from a target-format integer at ADDR which is |
| 38 | LEN bytes long. */ |
| 39 | |
| 40 | #if TARGET_CHAR_BIT != 8 || HOST_CHAR_BIT != 8 |
| 41 | /* 8 bit characters are a pretty safe assumption these days, so we |
| 42 | assume it throughout all these swapping routines. If we had to deal with |
| 43 | 9 bit characters, we would need to make len be in bits and would have |
| 44 | to re-write these routines... */ |
| 45 | you lose |
| 46 | #endif |
| 47 | |
| 48 | LONGEST |
| 49 | extract_signed_integer (const gdb_byte *addr, int len, |
| 50 | enum bfd_endian byte_order) |
| 51 | { |
| 52 | LONGEST retval; |
| 53 | const unsigned char *p; |
| 54 | const unsigned char *startaddr = addr; |
| 55 | const unsigned char *endaddr = startaddr + len; |
| 56 | |
| 57 | if (len > (int) sizeof (LONGEST)) |
| 58 | error (_("\ |
| 59 | That operation is not available on integers of more than %d bytes."), |
| 60 | (int) sizeof (LONGEST)); |
| 61 | |
| 62 | /* Start at the most significant end of the integer, and work towards |
| 63 | the least significant. */ |
| 64 | if (byte_order == BFD_ENDIAN_BIG) |
| 65 | { |
| 66 | p = startaddr; |
| 67 | /* Do the sign extension once at the start. */ |
| 68 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
| 69 | for (++p; p < endaddr; ++p) |
| 70 | retval = (retval << 8) | *p; |
| 71 | } |
| 72 | else |
| 73 | { |
| 74 | p = endaddr - 1; |
| 75 | /* Do the sign extension once at the start. */ |
| 76 | retval = ((LONGEST) * p ^ 0x80) - 0x80; |
| 77 | for (--p; p >= startaddr; --p) |
| 78 | retval = (retval << 8) | *p; |
| 79 | } |
| 80 | return retval; |
| 81 | } |
| 82 | |
| 83 | ULONGEST |
| 84 | extract_unsigned_integer (const gdb_byte *addr, int len, |
| 85 | enum bfd_endian byte_order) |
| 86 | { |
| 87 | ULONGEST retval; |
| 88 | const unsigned char *p; |
| 89 | const unsigned char *startaddr = addr; |
| 90 | const unsigned char *endaddr = startaddr + len; |
| 91 | |
| 92 | if (len > (int) sizeof (ULONGEST)) |
| 93 | error (_("\ |
| 94 | That operation is not available on integers of more than %d bytes."), |
| 95 | (int) sizeof (ULONGEST)); |
| 96 | |
| 97 | /* Start at the most significant end of the integer, and work towards |
| 98 | the least significant. */ |
| 99 | retval = 0; |
| 100 | if (byte_order == BFD_ENDIAN_BIG) |
| 101 | { |
| 102 | for (p = startaddr; p < endaddr; ++p) |
| 103 | retval = (retval << 8) | *p; |
| 104 | } |
| 105 | else |
| 106 | { |
| 107 | for (p = endaddr - 1; p >= startaddr; --p) |
| 108 | retval = (retval << 8) | *p; |
| 109 | } |
| 110 | return retval; |
| 111 | } |
| 112 | |
| 113 | /* Sometimes a long long unsigned integer can be extracted as a |
| 114 | LONGEST value. This is done so that we can print these values |
| 115 | better. If this integer can be converted to a LONGEST, this |
| 116 | function returns 1 and sets *PVAL. Otherwise it returns 0. */ |
| 117 | |
| 118 | int |
| 119 | extract_long_unsigned_integer (const gdb_byte *addr, int orig_len, |
| 120 | enum bfd_endian byte_order, LONGEST *pval) |
| 121 | { |
| 122 | const gdb_byte *p; |
| 123 | const gdb_byte *first_addr; |
| 124 | int len; |
| 125 | |
| 126 | len = orig_len; |
| 127 | if (byte_order == BFD_ENDIAN_BIG) |
| 128 | { |
| 129 | for (p = addr; |
| 130 | len > (int) sizeof (LONGEST) && p < addr + orig_len; |
| 131 | p++) |
| 132 | { |
| 133 | if (*p == 0) |
| 134 | len--; |
| 135 | else |
| 136 | break; |
| 137 | } |
| 138 | first_addr = p; |
| 139 | } |
| 140 | else |
| 141 | { |
| 142 | first_addr = addr; |
| 143 | for (p = addr + orig_len - 1; |
| 144 | len > (int) sizeof (LONGEST) && p >= addr; |
| 145 | p--) |
| 146 | { |
| 147 | if (*p == 0) |
| 148 | len--; |
| 149 | else |
| 150 | break; |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | if (len <= (int) sizeof (LONGEST)) |
| 155 | { |
| 156 | *pval = (LONGEST) extract_unsigned_integer (first_addr, |
| 157 | sizeof (LONGEST), |
| 158 | byte_order); |
| 159 | return 1; |
| 160 | } |
| 161 | |
| 162 | return 0; |
| 163 | } |
| 164 | |
| 165 | |
| 166 | /* Treat the bytes at BUF as a pointer of type TYPE, and return the |
| 167 | address it represents. */ |
| 168 | CORE_ADDR |
| 169 | extract_typed_address (const gdb_byte *buf, struct type *type) |
| 170 | { |
| 171 | if (TYPE_CODE (type) != TYPE_CODE_PTR |
| 172 | && TYPE_CODE (type) != TYPE_CODE_REF) |
| 173 | internal_error (__FILE__, __LINE__, |
| 174 | _("extract_typed_address: " |
| 175 | "type is not a pointer or reference")); |
| 176 | |
| 177 | return gdbarch_pointer_to_address (get_type_arch (type), type, buf); |
| 178 | } |
| 179 | |
| 180 | /* All 'store' functions accept a host-format integer and store a |
| 181 | target-format integer at ADDR which is LEN bytes long. */ |
| 182 | |
| 183 | void |
| 184 | store_signed_integer (gdb_byte *addr, int len, |
| 185 | enum bfd_endian byte_order, LONGEST val) |
| 186 | { |
| 187 | gdb_byte *p; |
| 188 | gdb_byte *startaddr = addr; |
| 189 | gdb_byte *endaddr = startaddr + len; |
| 190 | |
| 191 | /* Start at the least significant end of the integer, and work towards |
| 192 | the most significant. */ |
| 193 | if (byte_order == BFD_ENDIAN_BIG) |
| 194 | { |
| 195 | for (p = endaddr - 1; p >= startaddr; --p) |
| 196 | { |
| 197 | *p = val & 0xff; |
| 198 | val >>= 8; |
| 199 | } |
| 200 | } |
| 201 | else |
| 202 | { |
| 203 | for (p = startaddr; p < endaddr; ++p) |
| 204 | { |
| 205 | *p = val & 0xff; |
| 206 | val >>= 8; |
| 207 | } |
| 208 | } |
| 209 | } |
| 210 | |
| 211 | void |
| 212 | store_unsigned_integer (gdb_byte *addr, int len, |
| 213 | enum bfd_endian byte_order, ULONGEST val) |
| 214 | { |
| 215 | unsigned char *p; |
| 216 | unsigned char *startaddr = (unsigned char *) addr; |
| 217 | unsigned char *endaddr = startaddr + len; |
| 218 | |
| 219 | /* Start at the least significant end of the integer, and work towards |
| 220 | the most significant. */ |
| 221 | if (byte_order == BFD_ENDIAN_BIG) |
| 222 | { |
| 223 | for (p = endaddr - 1; p >= startaddr; --p) |
| 224 | { |
| 225 | *p = val & 0xff; |
| 226 | val >>= 8; |
| 227 | } |
| 228 | } |
| 229 | else |
| 230 | { |
| 231 | for (p = startaddr; p < endaddr; ++p) |
| 232 | { |
| 233 | *p = val & 0xff; |
| 234 | val >>= 8; |
| 235 | } |
| 236 | } |
| 237 | } |
| 238 | |
| 239 | /* Store the address ADDR as a pointer of type TYPE at BUF, in target |
| 240 | form. */ |
| 241 | void |
| 242 | store_typed_address (gdb_byte *buf, struct type *type, CORE_ADDR addr) |
| 243 | { |
| 244 | if (TYPE_CODE (type) != TYPE_CODE_PTR |
| 245 | && TYPE_CODE (type) != TYPE_CODE_REF) |
| 246 | internal_error (__FILE__, __LINE__, |
| 247 | _("store_typed_address: " |
| 248 | "type is not a pointer or reference")); |
| 249 | |
| 250 | gdbarch_address_to_pointer (get_type_arch (type), type, buf, addr); |
| 251 | } |
| 252 | |
| 253 | |
| 254 | |
| 255 | /* Return a `value' with the contents of (virtual or cooked) register |
| 256 | REGNUM as found in the specified FRAME. The register's type is |
| 257 | determined by register_type(). */ |
| 258 | |
| 259 | struct value * |
| 260 | value_of_register (int regnum, struct frame_info *frame) |
| 261 | { |
| 262 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 263 | struct value *reg_val; |
| 264 | |
| 265 | /* User registers lie completely outside of the range of normal |
| 266 | registers. Catch them early so that the target never sees them. */ |
| 267 | if (regnum >= gdbarch_num_regs (gdbarch) |
| 268 | + gdbarch_num_pseudo_regs (gdbarch)) |
| 269 | return value_of_user_reg (regnum, frame); |
| 270 | |
| 271 | reg_val = value_of_register_lazy (frame, regnum); |
| 272 | value_fetch_lazy (reg_val); |
| 273 | return reg_val; |
| 274 | } |
| 275 | |
| 276 | /* Return a `value' with the contents of (virtual or cooked) register |
| 277 | REGNUM as found in the specified FRAME. The register's type is |
| 278 | determined by register_type(). The value is not fetched. */ |
| 279 | |
| 280 | struct value * |
| 281 | value_of_register_lazy (struct frame_info *frame, int regnum) |
| 282 | { |
| 283 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 284 | struct value *reg_val; |
| 285 | |
| 286 | gdb_assert (regnum < (gdbarch_num_regs (gdbarch) |
| 287 | + gdbarch_num_pseudo_regs (gdbarch))); |
| 288 | |
| 289 | /* We should have a valid (i.e. non-sentinel) frame. */ |
| 290 | gdb_assert (frame_id_p (get_frame_id (frame))); |
| 291 | |
| 292 | reg_val = allocate_value_lazy (register_type (gdbarch, regnum)); |
| 293 | VALUE_LVAL (reg_val) = lval_register; |
| 294 | VALUE_REGNUM (reg_val) = regnum; |
| 295 | VALUE_FRAME_ID (reg_val) = get_frame_id (frame); |
| 296 | return reg_val; |
| 297 | } |
| 298 | |
| 299 | /* Given a pointer of type TYPE in target form in BUF, return the |
| 300 | address it represents. */ |
| 301 | CORE_ADDR |
| 302 | unsigned_pointer_to_address (struct gdbarch *gdbarch, |
| 303 | struct type *type, const gdb_byte *buf) |
| 304 | { |
| 305 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 306 | |
| 307 | return extract_unsigned_integer (buf, TYPE_LENGTH (type), byte_order); |
| 308 | } |
| 309 | |
| 310 | CORE_ADDR |
| 311 | signed_pointer_to_address (struct gdbarch *gdbarch, |
| 312 | struct type *type, const gdb_byte *buf) |
| 313 | { |
| 314 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 315 | |
| 316 | return extract_signed_integer (buf, TYPE_LENGTH (type), byte_order); |
| 317 | } |
| 318 | |
| 319 | /* Given an address, store it as a pointer of type TYPE in target |
| 320 | format in BUF. */ |
| 321 | void |
| 322 | unsigned_address_to_pointer (struct gdbarch *gdbarch, struct type *type, |
| 323 | gdb_byte *buf, CORE_ADDR addr) |
| 324 | { |
| 325 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 326 | |
| 327 | store_unsigned_integer (buf, TYPE_LENGTH (type), byte_order, addr); |
| 328 | } |
| 329 | |
| 330 | void |
| 331 | address_to_signed_pointer (struct gdbarch *gdbarch, struct type *type, |
| 332 | gdb_byte *buf, CORE_ADDR addr) |
| 333 | { |
| 334 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 335 | |
| 336 | store_signed_integer (buf, TYPE_LENGTH (type), byte_order, addr); |
| 337 | } |
| 338 | \f |
| 339 | /* Will calling read_var_value or locate_var_value on SYM end |
| 340 | up caring what frame it is being evaluated relative to? SYM must |
| 341 | be non-NULL. */ |
| 342 | int |
| 343 | symbol_read_needs_frame (struct symbol *sym) |
| 344 | { |
| 345 | if (SYMBOL_COMPUTED_OPS (sym) != NULL) |
| 346 | return SYMBOL_COMPUTED_OPS (sym)->read_needs_frame (sym); |
| 347 | |
| 348 | switch (SYMBOL_CLASS (sym)) |
| 349 | { |
| 350 | /* All cases listed explicitly so that gcc -Wall will detect it if |
| 351 | we failed to consider one. */ |
| 352 | case LOC_COMPUTED: |
| 353 | gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); |
| 354 | |
| 355 | case LOC_REGISTER: |
| 356 | case LOC_ARG: |
| 357 | case LOC_REF_ARG: |
| 358 | case LOC_REGPARM_ADDR: |
| 359 | case LOC_LOCAL: |
| 360 | return 1; |
| 361 | |
| 362 | case LOC_UNDEF: |
| 363 | case LOC_CONST: |
| 364 | case LOC_STATIC: |
| 365 | case LOC_TYPEDEF: |
| 366 | |
| 367 | case LOC_LABEL: |
| 368 | /* Getting the address of a label can be done independently of the block, |
| 369 | even if some *uses* of that address wouldn't work so well without |
| 370 | the right frame. */ |
| 371 | |
| 372 | case LOC_BLOCK: |
| 373 | case LOC_CONST_BYTES: |
| 374 | case LOC_UNRESOLVED: |
| 375 | case LOC_OPTIMIZED_OUT: |
| 376 | return 0; |
| 377 | } |
| 378 | return 1; |
| 379 | } |
| 380 | |
| 381 | /* Private data to be used with minsym_lookup_iterator_cb. */ |
| 382 | |
| 383 | struct minsym_lookup_data |
| 384 | { |
| 385 | /* The name of the minimal symbol we are searching for. */ |
| 386 | const char *name; |
| 387 | |
| 388 | /* The field where the callback should store the minimal symbol |
| 389 | if found. It should be initialized to NULL before the search |
| 390 | is started. */ |
| 391 | struct bound_minimal_symbol result; |
| 392 | }; |
| 393 | |
| 394 | /* A callback function for gdbarch_iterate_over_objfiles_in_search_order. |
| 395 | It searches by name for a minimal symbol within the given OBJFILE. |
| 396 | The arguments are passed via CB_DATA, which in reality is a pointer |
| 397 | to struct minsym_lookup_data. */ |
| 398 | |
| 399 | static int |
| 400 | minsym_lookup_iterator_cb (struct objfile *objfile, void *cb_data) |
| 401 | { |
| 402 | struct minsym_lookup_data *data = (struct minsym_lookup_data *) cb_data; |
| 403 | |
| 404 | gdb_assert (data->result.minsym == NULL); |
| 405 | |
| 406 | data->result = lookup_minimal_symbol (data->name, NULL, objfile); |
| 407 | |
| 408 | /* The iterator should stop iff a match was found. */ |
| 409 | return (data->result.minsym != NULL); |
| 410 | } |
| 411 | |
| 412 | /* A default implementation for the "la_read_var_value" hook in |
| 413 | the language vector which should work in most situations. */ |
| 414 | |
| 415 | struct value * |
| 416 | default_read_var_value (struct symbol *var, struct frame_info *frame) |
| 417 | { |
| 418 | struct value *v; |
| 419 | struct type *type = SYMBOL_TYPE (var); |
| 420 | CORE_ADDR addr; |
| 421 | |
| 422 | /* Call check_typedef on our type to make sure that, if TYPE is |
| 423 | a TYPE_CODE_TYPEDEF, its length is set to the length of the target type |
| 424 | instead of zero. However, we do not replace the typedef type by the |
| 425 | target type, because we want to keep the typedef in order to be able to |
| 426 | set the returned value type description correctly. */ |
| 427 | check_typedef (type); |
| 428 | |
| 429 | if (symbol_read_needs_frame (var)) |
| 430 | gdb_assert (frame); |
| 431 | |
| 432 | if (SYMBOL_COMPUTED_OPS (var) != NULL) |
| 433 | return SYMBOL_COMPUTED_OPS (var)->read_variable (var, frame); |
| 434 | |
| 435 | switch (SYMBOL_CLASS (var)) |
| 436 | { |
| 437 | case LOC_CONST: |
| 438 | if (is_dynamic_type (type)) |
| 439 | { |
| 440 | /* Value is a constant byte-sequence and needs no memory access. */ |
| 441 | type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0); |
| 442 | } |
| 443 | /* Put the constant back in target format. */ |
| 444 | v = allocate_value (type); |
| 445 | store_signed_integer (value_contents_raw (v), TYPE_LENGTH (type), |
| 446 | gdbarch_byte_order (get_type_arch (type)), |
| 447 | (LONGEST) SYMBOL_VALUE (var)); |
| 448 | VALUE_LVAL (v) = not_lval; |
| 449 | return v; |
| 450 | |
| 451 | case LOC_LABEL: |
| 452 | /* Put the constant back in target format. */ |
| 453 | v = allocate_value (type); |
| 454 | if (overlay_debugging) |
| 455 | { |
| 456 | CORE_ADDR addr |
| 457 | = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), |
| 458 | SYMBOL_OBJ_SECTION (symbol_objfile (var), |
| 459 | var)); |
| 460 | |
| 461 | store_typed_address (value_contents_raw (v), type, addr); |
| 462 | } |
| 463 | else |
| 464 | store_typed_address (value_contents_raw (v), type, |
| 465 | SYMBOL_VALUE_ADDRESS (var)); |
| 466 | VALUE_LVAL (v) = not_lval; |
| 467 | return v; |
| 468 | |
| 469 | case LOC_CONST_BYTES: |
| 470 | if (is_dynamic_type (type)) |
| 471 | { |
| 472 | /* Value is a constant byte-sequence and needs no memory access. */ |
| 473 | type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0); |
| 474 | } |
| 475 | v = allocate_value (type); |
| 476 | memcpy (value_contents_raw (v), SYMBOL_VALUE_BYTES (var), |
| 477 | TYPE_LENGTH (type)); |
| 478 | VALUE_LVAL (v) = not_lval; |
| 479 | return v; |
| 480 | |
| 481 | case LOC_STATIC: |
| 482 | if (overlay_debugging) |
| 483 | addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var), |
| 484 | SYMBOL_OBJ_SECTION (symbol_objfile (var), |
| 485 | var)); |
| 486 | else |
| 487 | addr = SYMBOL_VALUE_ADDRESS (var); |
| 488 | break; |
| 489 | |
| 490 | case LOC_ARG: |
| 491 | addr = get_frame_args_address (frame); |
| 492 | if (!addr) |
| 493 | error (_("Unknown argument list address for `%s'."), |
| 494 | SYMBOL_PRINT_NAME (var)); |
| 495 | addr += SYMBOL_VALUE (var); |
| 496 | break; |
| 497 | |
| 498 | case LOC_REF_ARG: |
| 499 | { |
| 500 | struct value *ref; |
| 501 | CORE_ADDR argref; |
| 502 | |
| 503 | argref = get_frame_args_address (frame); |
| 504 | if (!argref) |
| 505 | error (_("Unknown argument list address for `%s'."), |
| 506 | SYMBOL_PRINT_NAME (var)); |
| 507 | argref += SYMBOL_VALUE (var); |
| 508 | ref = value_at (lookup_pointer_type (type), argref); |
| 509 | addr = value_as_address (ref); |
| 510 | break; |
| 511 | } |
| 512 | |
| 513 | case LOC_LOCAL: |
| 514 | addr = get_frame_locals_address (frame); |
| 515 | addr += SYMBOL_VALUE (var); |
| 516 | break; |
| 517 | |
| 518 | case LOC_TYPEDEF: |
| 519 | error (_("Cannot look up value of a typedef `%s'."), |
| 520 | SYMBOL_PRINT_NAME (var)); |
| 521 | break; |
| 522 | |
| 523 | case LOC_BLOCK: |
| 524 | if (overlay_debugging) |
| 525 | addr = symbol_overlayed_address |
| 526 | (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), |
| 527 | SYMBOL_OBJ_SECTION (symbol_objfile (var), var)); |
| 528 | else |
| 529 | addr = BLOCK_START (SYMBOL_BLOCK_VALUE (var)); |
| 530 | break; |
| 531 | |
| 532 | case LOC_REGISTER: |
| 533 | case LOC_REGPARM_ADDR: |
| 534 | { |
| 535 | int regno = SYMBOL_REGISTER_OPS (var) |
| 536 | ->register_number (var, get_frame_arch (frame)); |
| 537 | struct value *regval; |
| 538 | |
| 539 | if (SYMBOL_CLASS (var) == LOC_REGPARM_ADDR) |
| 540 | { |
| 541 | regval = value_from_register (lookup_pointer_type (type), |
| 542 | regno, |
| 543 | frame); |
| 544 | |
| 545 | if (regval == NULL) |
| 546 | error (_("Value of register variable not available for `%s'."), |
| 547 | SYMBOL_PRINT_NAME (var)); |
| 548 | |
| 549 | addr = value_as_address (regval); |
| 550 | } |
| 551 | else |
| 552 | { |
| 553 | regval = value_from_register (type, regno, frame); |
| 554 | |
| 555 | if (regval == NULL) |
| 556 | error (_("Value of register variable not available for `%s'."), |
| 557 | SYMBOL_PRINT_NAME (var)); |
| 558 | return regval; |
| 559 | } |
| 560 | } |
| 561 | break; |
| 562 | |
| 563 | case LOC_COMPUTED: |
| 564 | gdb_assert_not_reached (_("LOC_COMPUTED variable missing a method")); |
| 565 | |
| 566 | case LOC_UNRESOLVED: |
| 567 | { |
| 568 | struct minsym_lookup_data lookup_data; |
| 569 | struct minimal_symbol *msym; |
| 570 | struct obj_section *obj_section; |
| 571 | |
| 572 | memset (&lookup_data, 0, sizeof (lookup_data)); |
| 573 | lookup_data.name = SYMBOL_LINKAGE_NAME (var); |
| 574 | |
| 575 | gdbarch_iterate_over_objfiles_in_search_order |
| 576 | (symbol_arch (var), |
| 577 | minsym_lookup_iterator_cb, &lookup_data, |
| 578 | symbol_objfile (var)); |
| 579 | msym = lookup_data.result.minsym; |
| 580 | |
| 581 | if (msym == NULL) |
| 582 | error (_("No global symbol \"%s\"."), SYMBOL_LINKAGE_NAME (var)); |
| 583 | if (overlay_debugging) |
| 584 | addr = symbol_overlayed_address (BMSYMBOL_VALUE_ADDRESS (lookup_data.result), |
| 585 | MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, |
| 586 | msym)); |
| 587 | else |
| 588 | addr = BMSYMBOL_VALUE_ADDRESS (lookup_data.result); |
| 589 | |
| 590 | obj_section = MSYMBOL_OBJ_SECTION (lookup_data.result.objfile, msym); |
| 591 | if (obj_section |
| 592 | && (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0) |
| 593 | addr = target_translate_tls_address (obj_section->objfile, addr); |
| 594 | } |
| 595 | break; |
| 596 | |
| 597 | case LOC_OPTIMIZED_OUT: |
| 598 | return allocate_optimized_out_value (type); |
| 599 | |
| 600 | default: |
| 601 | error (_("Cannot look up value of a botched symbol `%s'."), |
| 602 | SYMBOL_PRINT_NAME (var)); |
| 603 | break; |
| 604 | } |
| 605 | |
| 606 | v = value_at_lazy (type, addr); |
| 607 | return v; |
| 608 | } |
| 609 | |
| 610 | /* Calls VAR's language la_read_var_value hook with the given arguments. */ |
| 611 | |
| 612 | struct value * |
| 613 | read_var_value (struct symbol *var, struct frame_info *frame) |
| 614 | { |
| 615 | const struct language_defn *lang = language_def (SYMBOL_LANGUAGE (var)); |
| 616 | |
| 617 | gdb_assert (lang != NULL); |
| 618 | gdb_assert (lang->la_read_var_value != NULL); |
| 619 | |
| 620 | return lang->la_read_var_value (var, frame); |
| 621 | } |
| 622 | |
| 623 | /* Install default attributes for register values. */ |
| 624 | |
| 625 | struct value * |
| 626 | default_value_from_register (struct gdbarch *gdbarch, struct type *type, |
| 627 | int regnum, struct frame_id frame_id) |
| 628 | { |
| 629 | int len = TYPE_LENGTH (type); |
| 630 | struct value *value = allocate_value (type); |
| 631 | |
| 632 | VALUE_LVAL (value) = lval_register; |
| 633 | VALUE_FRAME_ID (value) = frame_id; |
| 634 | VALUE_REGNUM (value) = regnum; |
| 635 | |
| 636 | /* Any structure stored in more than one register will always be |
| 637 | an integral number of registers. Otherwise, you need to do |
| 638 | some fiddling with the last register copied here for little |
| 639 | endian machines. */ |
| 640 | if (gdbarch_byte_order (gdbarch) == BFD_ENDIAN_BIG |
| 641 | && len < register_size (gdbarch, regnum)) |
| 642 | /* Big-endian, and we want less than full size. */ |
| 643 | set_value_offset (value, register_size (gdbarch, regnum) - len); |
| 644 | else |
| 645 | set_value_offset (value, 0); |
| 646 | |
| 647 | return value; |
| 648 | } |
| 649 | |
| 650 | /* VALUE must be an lval_register value. If regnum is the value's |
| 651 | associated register number, and len the length of the values type, |
| 652 | read one or more registers in FRAME, starting with register REGNUM, |
| 653 | until we've read LEN bytes. |
| 654 | |
| 655 | If any of the registers we try to read are optimized out, then mark the |
| 656 | complete resulting value as optimized out. */ |
| 657 | |
| 658 | void |
| 659 | read_frame_register_value (struct value *value, struct frame_info *frame) |
| 660 | { |
| 661 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 662 | int offset = 0; |
| 663 | int reg_offset = value_offset (value); |
| 664 | int regnum = VALUE_REGNUM (value); |
| 665 | int len = type_length_units (check_typedef (value_type (value))); |
| 666 | |
| 667 | gdb_assert (VALUE_LVAL (value) == lval_register); |
| 668 | |
| 669 | /* Skip registers wholly inside of REG_OFFSET. */ |
| 670 | while (reg_offset >= register_size (gdbarch, regnum)) |
| 671 | { |
| 672 | reg_offset -= register_size (gdbarch, regnum); |
| 673 | regnum++; |
| 674 | } |
| 675 | |
| 676 | /* Copy the data. */ |
| 677 | while (len > 0) |
| 678 | { |
| 679 | struct value *regval = get_frame_register_value (frame, regnum); |
| 680 | int reg_len = type_length_units (value_type (regval)) - reg_offset; |
| 681 | |
| 682 | /* If the register length is larger than the number of bytes |
| 683 | remaining to copy, then only copy the appropriate bytes. */ |
| 684 | if (reg_len > len) |
| 685 | reg_len = len; |
| 686 | |
| 687 | value_contents_copy (value, offset, regval, reg_offset, reg_len); |
| 688 | |
| 689 | offset += reg_len; |
| 690 | len -= reg_len; |
| 691 | reg_offset = 0; |
| 692 | regnum++; |
| 693 | } |
| 694 | } |
| 695 | |
| 696 | /* Return a value of type TYPE, stored in register REGNUM, in frame FRAME. */ |
| 697 | |
| 698 | struct value * |
| 699 | value_from_register (struct type *type, int regnum, struct frame_info *frame) |
| 700 | { |
| 701 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 702 | struct type *type1 = check_typedef (type); |
| 703 | struct value *v; |
| 704 | |
| 705 | if (gdbarch_convert_register_p (gdbarch, regnum, type1)) |
| 706 | { |
| 707 | int optim, unavail, ok; |
| 708 | |
| 709 | /* The ISA/ABI need to something weird when obtaining the |
| 710 | specified value from this register. It might need to |
| 711 | re-order non-adjacent, starting with REGNUM (see MIPS and |
| 712 | i386). It might need to convert the [float] register into |
| 713 | the corresponding [integer] type (see Alpha). The assumption |
| 714 | is that gdbarch_register_to_value populates the entire value |
| 715 | including the location. */ |
| 716 | v = allocate_value (type); |
| 717 | VALUE_LVAL (v) = lval_register; |
| 718 | VALUE_FRAME_ID (v) = get_frame_id (frame); |
| 719 | VALUE_REGNUM (v) = regnum; |
| 720 | ok = gdbarch_register_to_value (gdbarch, frame, regnum, type1, |
| 721 | value_contents_raw (v), &optim, |
| 722 | &unavail); |
| 723 | |
| 724 | if (!ok) |
| 725 | { |
| 726 | if (optim) |
| 727 | mark_value_bytes_optimized_out (v, 0, TYPE_LENGTH (type)); |
| 728 | if (unavail) |
| 729 | mark_value_bytes_unavailable (v, 0, TYPE_LENGTH (type)); |
| 730 | } |
| 731 | } |
| 732 | else |
| 733 | { |
| 734 | /* Construct the value. */ |
| 735 | v = gdbarch_value_from_register (gdbarch, type, |
| 736 | regnum, get_frame_id (frame)); |
| 737 | |
| 738 | /* Get the data. */ |
| 739 | read_frame_register_value (v, frame); |
| 740 | } |
| 741 | |
| 742 | return v; |
| 743 | } |
| 744 | |
| 745 | /* Return contents of register REGNUM in frame FRAME as address. |
| 746 | Will abort if register value is not available. */ |
| 747 | |
| 748 | CORE_ADDR |
| 749 | address_from_register (int regnum, struct frame_info *frame) |
| 750 | { |
| 751 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 752 | struct type *type = builtin_type (gdbarch)->builtin_data_ptr; |
| 753 | struct value *value; |
| 754 | CORE_ADDR result; |
| 755 | |
| 756 | /* This routine may be called during early unwinding, at a time |
| 757 | where the ID of FRAME is not yet known. Calling value_from_register |
| 758 | would therefore abort in get_frame_id. However, since we only need |
| 759 | a temporary value that is never used as lvalue, we actually do not |
| 760 | really need to set its VALUE_FRAME_ID. Therefore, we re-implement |
| 761 | the core of value_from_register, but use the null_frame_id. */ |
| 762 | |
| 763 | /* Some targets require a special conversion routine even for plain |
| 764 | pointer types. Avoid constructing a value object in those cases. */ |
| 765 | if (gdbarch_convert_register_p (gdbarch, regnum, type)) |
| 766 | { |
| 767 | gdb_byte *buf = alloca (TYPE_LENGTH (type)); |
| 768 | int optim, unavail, ok; |
| 769 | |
| 770 | ok = gdbarch_register_to_value (gdbarch, frame, regnum, type, |
| 771 | buf, &optim, &unavail); |
| 772 | if (!ok) |
| 773 | { |
| 774 | /* This function is used while computing a location expression. |
| 775 | Complain about the value being optimized out, rather than |
| 776 | letting value_as_address complain about some random register |
| 777 | the expression depends on not being saved. */ |
| 778 | error_value_optimized_out (); |
| 779 | } |
| 780 | |
| 781 | return unpack_long (type, buf); |
| 782 | } |
| 783 | |
| 784 | value = gdbarch_value_from_register (gdbarch, type, regnum, null_frame_id); |
| 785 | read_frame_register_value (value, frame); |
| 786 | |
| 787 | if (value_optimized_out (value)) |
| 788 | { |
| 789 | /* This function is used while computing a location expression. |
| 790 | Complain about the value being optimized out, rather than |
| 791 | letting value_as_address complain about some random register |
| 792 | the expression depends on not being saved. */ |
| 793 | error_value_optimized_out (); |
| 794 | } |
| 795 | |
| 796 | result = value_as_address (value); |
| 797 | release_value (value); |
| 798 | value_free (value); |
| 799 | |
| 800 | return result; |
| 801 | } |
| 802 | |