| 1 | /* Low level packing and unpacking of values for GDB, the GNU Debugger. |
| 2 | |
| 3 | Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, |
| 4 | 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005 Free |
| 5 | Software Foundation, Inc. |
| 6 | |
| 7 | This file is part of GDB. |
| 8 | |
| 9 | This program is free software; you can redistribute it and/or modify |
| 10 | it under the terms of the GNU General Public License as published by |
| 11 | the Free Software Foundation; either version 2 of the License, or |
| 12 | (at your option) any later version. |
| 13 | |
| 14 | This program is distributed in the hope that it will be useful, |
| 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 17 | GNU General Public License for more details. |
| 18 | |
| 19 | You should have received a copy of the GNU General Public License |
| 20 | along with this program; if not, write to the Free Software |
| 21 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 22 | Boston, MA 02111-1307, USA. */ |
| 23 | |
| 24 | #include "defs.h" |
| 25 | #include "gdb_string.h" |
| 26 | #include "symtab.h" |
| 27 | #include "gdbtypes.h" |
| 28 | #include "value.h" |
| 29 | #include "gdbcore.h" |
| 30 | #include "command.h" |
| 31 | #include "gdbcmd.h" |
| 32 | #include "target.h" |
| 33 | #include "language.h" |
| 34 | #include "scm-lang.h" |
| 35 | #include "demangle.h" |
| 36 | #include "doublest.h" |
| 37 | #include "gdb_assert.h" |
| 38 | #include "regcache.h" |
| 39 | #include "block.h" |
| 40 | |
| 41 | /* Prototypes for exported functions. */ |
| 42 | |
| 43 | void _initialize_values (void); |
| 44 | |
| 45 | struct value |
| 46 | { |
| 47 | /* Type of value; either not an lval, or one of the various |
| 48 | different possible kinds of lval. */ |
| 49 | enum lval_type lval; |
| 50 | |
| 51 | /* Is it modifiable? Only relevant if lval != not_lval. */ |
| 52 | int modifiable; |
| 53 | |
| 54 | /* Location of value (if lval). */ |
| 55 | union |
| 56 | { |
| 57 | /* If lval == lval_memory, this is the address in the inferior. |
| 58 | If lval == lval_register, this is the byte offset into the |
| 59 | registers structure. */ |
| 60 | CORE_ADDR address; |
| 61 | |
| 62 | /* Pointer to internal variable. */ |
| 63 | struct internalvar *internalvar; |
| 64 | } location; |
| 65 | |
| 66 | /* Describes offset of a value within lval of a structure in bytes. |
| 67 | If lval == lval_memory, this is an offset to the address. If |
| 68 | lval == lval_register, this is a further offset from |
| 69 | location.address within the registers structure. Note also the |
| 70 | member embedded_offset below. */ |
| 71 | int offset; |
| 72 | |
| 73 | /* Only used for bitfields; number of bits contained in them. */ |
| 74 | int bitsize; |
| 75 | |
| 76 | /* Only used for bitfields; position of start of field. For |
| 77 | BITS_BIG_ENDIAN=0 targets, it is the position of the LSB. For |
| 78 | BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */ |
| 79 | int bitpos; |
| 80 | |
| 81 | /* Frame register value is relative to. This will be described in |
| 82 | the lval enum above as "lval_register". */ |
| 83 | struct frame_id frame_id; |
| 84 | |
| 85 | /* Type of the value. */ |
| 86 | struct type *type; |
| 87 | |
| 88 | /* If a value represents a C++ object, then the `type' field gives |
| 89 | the object's compile-time type. If the object actually belongs |
| 90 | to some class derived from `type', perhaps with other base |
| 91 | classes and additional members, then `type' is just a subobject |
| 92 | of the real thing, and the full object is probably larger than |
| 93 | `type' would suggest. |
| 94 | |
| 95 | If `type' is a dynamic class (i.e. one with a vtable), then GDB |
| 96 | can actually determine the object's run-time type by looking at |
| 97 | the run-time type information in the vtable. When this |
| 98 | information is available, we may elect to read in the entire |
| 99 | object, for several reasons: |
| 100 | |
| 101 | - When printing the value, the user would probably rather see the |
| 102 | full object, not just the limited portion apparent from the |
| 103 | compile-time type. |
| 104 | |
| 105 | - If `type' has virtual base classes, then even printing `type' |
| 106 | alone may require reaching outside the `type' portion of the |
| 107 | object to wherever the virtual base class has been stored. |
| 108 | |
| 109 | When we store the entire object, `enclosing_type' is the run-time |
| 110 | type -- the complete object -- and `embedded_offset' is the |
| 111 | offset of `type' within that larger type, in bytes. The |
| 112 | value_contents() macro takes `embedded_offset' into account, so |
| 113 | most GDB code continues to see the `type' portion of the value, |
| 114 | just as the inferior would. |
| 115 | |
| 116 | If `type' is a pointer to an object, then `enclosing_type' is a |
| 117 | pointer to the object's run-time type, and `pointed_to_offset' is |
| 118 | the offset in bytes from the full object to the pointed-to object |
| 119 | -- that is, the value `embedded_offset' would have if we followed |
| 120 | the pointer and fetched the complete object. (I don't really see |
| 121 | the point. Why not just determine the run-time type when you |
| 122 | indirect, and avoid the special case? The contents don't matter |
| 123 | until you indirect anyway.) |
| 124 | |
| 125 | If we're not doing anything fancy, `enclosing_type' is equal to |
| 126 | `type', and `embedded_offset' is zero, so everything works |
| 127 | normally. */ |
| 128 | struct type *enclosing_type; |
| 129 | int embedded_offset; |
| 130 | int pointed_to_offset; |
| 131 | |
| 132 | /* Values are stored in a chain, so that they can be deleted easily |
| 133 | over calls to the inferior. Values assigned to internal |
| 134 | variables or put into the value history are taken off this |
| 135 | list. */ |
| 136 | struct value *next; |
| 137 | |
| 138 | /* Register number if the value is from a register. */ |
| 139 | short regnum; |
| 140 | |
| 141 | /* If zero, contents of this value are in the contents field. If |
| 142 | nonzero, contents are in inferior memory at address in the |
| 143 | location.address field plus the offset field (and the lval field |
| 144 | should be lval_memory). |
| 145 | |
| 146 | WARNING: This field is used by the code which handles watchpoints |
| 147 | (see breakpoint.c) to decide whether a particular value can be |
| 148 | watched by hardware watchpoints. If the lazy flag is set for |
| 149 | some member of a value chain, it is assumed that this member of |
| 150 | the chain doesn't need to be watched as part of watching the |
| 151 | value itself. This is how GDB avoids watching the entire struct |
| 152 | or array when the user wants to watch a single struct member or |
| 153 | array element. If you ever change the way lazy flag is set and |
| 154 | reset, be sure to consider this use as well! */ |
| 155 | char lazy; |
| 156 | |
| 157 | /* If nonzero, this is the value of a variable which does not |
| 158 | actually exist in the program. */ |
| 159 | char optimized_out; |
| 160 | |
| 161 | /* Actual contents of the value. For use of this value; setting it |
| 162 | uses the stuff above. Not valid if lazy is nonzero. Target |
| 163 | byte-order. We force it to be aligned properly for any possible |
| 164 | value. Note that a value therefore extends beyond what is |
| 165 | declared here. */ |
| 166 | union |
| 167 | { |
| 168 | gdb_byte contents[1]; |
| 169 | DOUBLEST force_doublest_align; |
| 170 | LONGEST force_longest_align; |
| 171 | CORE_ADDR force_core_addr_align; |
| 172 | void *force_pointer_align; |
| 173 | } aligner; |
| 174 | /* Do not add any new members here -- contents above will trash |
| 175 | them. */ |
| 176 | }; |
| 177 | |
| 178 | /* Prototypes for local functions. */ |
| 179 | |
| 180 | static void show_values (char *, int); |
| 181 | |
| 182 | static void show_convenience (char *, int); |
| 183 | |
| 184 | |
| 185 | /* The value-history records all the values printed |
| 186 | by print commands during this session. Each chunk |
| 187 | records 60 consecutive values. The first chunk on |
| 188 | the chain records the most recent values. |
| 189 | The total number of values is in value_history_count. */ |
| 190 | |
| 191 | #define VALUE_HISTORY_CHUNK 60 |
| 192 | |
| 193 | struct value_history_chunk |
| 194 | { |
| 195 | struct value_history_chunk *next; |
| 196 | struct value *values[VALUE_HISTORY_CHUNK]; |
| 197 | }; |
| 198 | |
| 199 | /* Chain of chunks now in use. */ |
| 200 | |
| 201 | static struct value_history_chunk *value_history_chain; |
| 202 | |
| 203 | static int value_history_count; /* Abs number of last entry stored */ |
| 204 | \f |
| 205 | /* List of all value objects currently allocated |
| 206 | (except for those released by calls to release_value) |
| 207 | This is so they can be freed after each command. */ |
| 208 | |
| 209 | static struct value *all_values; |
| 210 | |
| 211 | /* Allocate a value that has the correct length for type TYPE. */ |
| 212 | |
| 213 | struct value * |
| 214 | allocate_value (struct type *type) |
| 215 | { |
| 216 | struct value *val; |
| 217 | struct type *atype = check_typedef (type); |
| 218 | |
| 219 | val = (struct value *) xzalloc (sizeof (struct value) + TYPE_LENGTH (atype)); |
| 220 | val->next = all_values; |
| 221 | all_values = val; |
| 222 | val->type = type; |
| 223 | val->enclosing_type = type; |
| 224 | VALUE_LVAL (val) = not_lval; |
| 225 | VALUE_ADDRESS (val) = 0; |
| 226 | VALUE_FRAME_ID (val) = null_frame_id; |
| 227 | val->offset = 0; |
| 228 | val->bitpos = 0; |
| 229 | val->bitsize = 0; |
| 230 | VALUE_REGNUM (val) = -1; |
| 231 | val->lazy = 0; |
| 232 | val->optimized_out = 0; |
| 233 | val->embedded_offset = 0; |
| 234 | val->pointed_to_offset = 0; |
| 235 | val->modifiable = 1; |
| 236 | return val; |
| 237 | } |
| 238 | |
| 239 | /* Allocate a value that has the correct length |
| 240 | for COUNT repetitions type TYPE. */ |
| 241 | |
| 242 | struct value * |
| 243 | allocate_repeat_value (struct type *type, int count) |
| 244 | { |
| 245 | int low_bound = current_language->string_lower_bound; /* ??? */ |
| 246 | /* FIXME-type-allocation: need a way to free this type when we are |
| 247 | done with it. */ |
| 248 | struct type *range_type |
| 249 | = create_range_type ((struct type *) NULL, builtin_type_int, |
| 250 | low_bound, count + low_bound - 1); |
| 251 | /* FIXME-type-allocation: need a way to free this type when we are |
| 252 | done with it. */ |
| 253 | return allocate_value (create_array_type ((struct type *) NULL, |
| 254 | type, range_type)); |
| 255 | } |
| 256 | |
| 257 | /* Accessor methods. */ |
| 258 | |
| 259 | struct value * |
| 260 | value_next (struct value *value) |
| 261 | { |
| 262 | return value->next; |
| 263 | } |
| 264 | |
| 265 | struct type * |
| 266 | value_type (struct value *value) |
| 267 | { |
| 268 | return value->type; |
| 269 | } |
| 270 | void |
| 271 | deprecated_set_value_type (struct value *value, struct type *type) |
| 272 | { |
| 273 | value->type = type; |
| 274 | } |
| 275 | |
| 276 | int |
| 277 | value_offset (struct value *value) |
| 278 | { |
| 279 | return value->offset; |
| 280 | } |
| 281 | void |
| 282 | set_value_offset (struct value *value, int offset) |
| 283 | { |
| 284 | value->offset = offset; |
| 285 | } |
| 286 | |
| 287 | int |
| 288 | value_bitpos (struct value *value) |
| 289 | { |
| 290 | return value->bitpos; |
| 291 | } |
| 292 | void |
| 293 | set_value_bitpos (struct value *value, int bit) |
| 294 | { |
| 295 | value->bitpos = bit; |
| 296 | } |
| 297 | |
| 298 | int |
| 299 | value_bitsize (struct value *value) |
| 300 | { |
| 301 | return value->bitsize; |
| 302 | } |
| 303 | void |
| 304 | set_value_bitsize (struct value *value, int bit) |
| 305 | { |
| 306 | value->bitsize = bit; |
| 307 | } |
| 308 | |
| 309 | gdb_byte * |
| 310 | value_contents_raw (struct value *value) |
| 311 | { |
| 312 | return value->aligner.contents + value->embedded_offset; |
| 313 | } |
| 314 | |
| 315 | gdb_byte * |
| 316 | value_contents_all_raw (struct value *value) |
| 317 | { |
| 318 | return value->aligner.contents; |
| 319 | } |
| 320 | |
| 321 | struct type * |
| 322 | value_enclosing_type (struct value *value) |
| 323 | { |
| 324 | return value->enclosing_type; |
| 325 | } |
| 326 | |
| 327 | const gdb_byte * |
| 328 | value_contents_all (struct value *value) |
| 329 | { |
| 330 | if (value->lazy) |
| 331 | value_fetch_lazy (value); |
| 332 | return value->aligner.contents; |
| 333 | } |
| 334 | |
| 335 | int |
| 336 | value_lazy (struct value *value) |
| 337 | { |
| 338 | return value->lazy; |
| 339 | } |
| 340 | |
| 341 | void |
| 342 | set_value_lazy (struct value *value, int val) |
| 343 | { |
| 344 | value->lazy = val; |
| 345 | } |
| 346 | |
| 347 | const gdb_byte * |
| 348 | value_contents (struct value *value) |
| 349 | { |
| 350 | return value_contents_writeable (value); |
| 351 | } |
| 352 | |
| 353 | gdb_byte * |
| 354 | value_contents_writeable (struct value *value) |
| 355 | { |
| 356 | if (value->lazy) |
| 357 | value_fetch_lazy (value); |
| 358 | return value->aligner.contents; |
| 359 | } |
| 360 | |
| 361 | /* Return non-zero if VAL1 and VAL2 have the same contents. Note that |
| 362 | this function is different from value_equal; in C the operator == |
| 363 | can return 0 even if the two values being compared are equal. */ |
| 364 | |
| 365 | int |
| 366 | value_contents_equal (struct value *val1, struct value *val2) |
| 367 | { |
| 368 | struct type *type1; |
| 369 | struct type *type2; |
| 370 | int len; |
| 371 | |
| 372 | type1 = check_typedef (value_type (val1)); |
| 373 | type2 = check_typedef (value_type (val2)); |
| 374 | len = TYPE_LENGTH (type1); |
| 375 | if (len != TYPE_LENGTH (type2)) |
| 376 | return 0; |
| 377 | |
| 378 | return (memcmp (value_contents (val1), value_contents (val2), len) == 0); |
| 379 | } |
| 380 | |
| 381 | int |
| 382 | value_optimized_out (struct value *value) |
| 383 | { |
| 384 | return value->optimized_out; |
| 385 | } |
| 386 | |
| 387 | void |
| 388 | set_value_optimized_out (struct value *value, int val) |
| 389 | { |
| 390 | value->optimized_out = val; |
| 391 | } |
| 392 | |
| 393 | int |
| 394 | value_embedded_offset (struct value *value) |
| 395 | { |
| 396 | return value->embedded_offset; |
| 397 | } |
| 398 | |
| 399 | void |
| 400 | set_value_embedded_offset (struct value *value, int val) |
| 401 | { |
| 402 | value->embedded_offset = val; |
| 403 | } |
| 404 | |
| 405 | int |
| 406 | value_pointed_to_offset (struct value *value) |
| 407 | { |
| 408 | return value->pointed_to_offset; |
| 409 | } |
| 410 | |
| 411 | void |
| 412 | set_value_pointed_to_offset (struct value *value, int val) |
| 413 | { |
| 414 | value->pointed_to_offset = val; |
| 415 | } |
| 416 | |
| 417 | enum lval_type * |
| 418 | deprecated_value_lval_hack (struct value *value) |
| 419 | { |
| 420 | return &value->lval; |
| 421 | } |
| 422 | |
| 423 | CORE_ADDR * |
| 424 | deprecated_value_address_hack (struct value *value) |
| 425 | { |
| 426 | return &value->location.address; |
| 427 | } |
| 428 | |
| 429 | struct internalvar ** |
| 430 | deprecated_value_internalvar_hack (struct value *value) |
| 431 | { |
| 432 | return &value->location.internalvar; |
| 433 | } |
| 434 | |
| 435 | struct frame_id * |
| 436 | deprecated_value_frame_id_hack (struct value *value) |
| 437 | { |
| 438 | return &value->frame_id; |
| 439 | } |
| 440 | |
| 441 | short * |
| 442 | deprecated_value_regnum_hack (struct value *value) |
| 443 | { |
| 444 | return &value->regnum; |
| 445 | } |
| 446 | |
| 447 | int |
| 448 | deprecated_value_modifiable (struct value *value) |
| 449 | { |
| 450 | return value->modifiable; |
| 451 | } |
| 452 | void |
| 453 | deprecated_set_value_modifiable (struct value *value, int modifiable) |
| 454 | { |
| 455 | value->modifiable = modifiable; |
| 456 | } |
| 457 | \f |
| 458 | /* Return a mark in the value chain. All values allocated after the |
| 459 | mark is obtained (except for those released) are subject to being freed |
| 460 | if a subsequent value_free_to_mark is passed the mark. */ |
| 461 | struct value * |
| 462 | value_mark (void) |
| 463 | { |
| 464 | return all_values; |
| 465 | } |
| 466 | |
| 467 | /* Free all values allocated since MARK was obtained by value_mark |
| 468 | (except for those released). */ |
| 469 | void |
| 470 | value_free_to_mark (struct value *mark) |
| 471 | { |
| 472 | struct value *val; |
| 473 | struct value *next; |
| 474 | |
| 475 | for (val = all_values; val && val != mark; val = next) |
| 476 | { |
| 477 | next = val->next; |
| 478 | value_free (val); |
| 479 | } |
| 480 | all_values = val; |
| 481 | } |
| 482 | |
| 483 | /* Free all the values that have been allocated (except for those released). |
| 484 | Called after each command, successful or not. */ |
| 485 | |
| 486 | void |
| 487 | free_all_values (void) |
| 488 | { |
| 489 | struct value *val; |
| 490 | struct value *next; |
| 491 | |
| 492 | for (val = all_values; val; val = next) |
| 493 | { |
| 494 | next = val->next; |
| 495 | value_free (val); |
| 496 | } |
| 497 | |
| 498 | all_values = 0; |
| 499 | } |
| 500 | |
| 501 | /* Remove VAL from the chain all_values |
| 502 | so it will not be freed automatically. */ |
| 503 | |
| 504 | void |
| 505 | release_value (struct value *val) |
| 506 | { |
| 507 | struct value *v; |
| 508 | |
| 509 | if (all_values == val) |
| 510 | { |
| 511 | all_values = val->next; |
| 512 | return; |
| 513 | } |
| 514 | |
| 515 | for (v = all_values; v; v = v->next) |
| 516 | { |
| 517 | if (v->next == val) |
| 518 | { |
| 519 | v->next = val->next; |
| 520 | break; |
| 521 | } |
| 522 | } |
| 523 | } |
| 524 | |
| 525 | /* Release all values up to mark */ |
| 526 | struct value * |
| 527 | value_release_to_mark (struct value *mark) |
| 528 | { |
| 529 | struct value *val; |
| 530 | struct value *next; |
| 531 | |
| 532 | for (val = next = all_values; next; next = next->next) |
| 533 | if (next->next == mark) |
| 534 | { |
| 535 | all_values = next->next; |
| 536 | next->next = NULL; |
| 537 | return val; |
| 538 | } |
| 539 | all_values = 0; |
| 540 | return val; |
| 541 | } |
| 542 | |
| 543 | /* Return a copy of the value ARG. |
| 544 | It contains the same contents, for same memory address, |
| 545 | but it's a different block of storage. */ |
| 546 | |
| 547 | struct value * |
| 548 | value_copy (struct value *arg) |
| 549 | { |
| 550 | struct type *encl_type = value_enclosing_type (arg); |
| 551 | struct value *val = allocate_value (encl_type); |
| 552 | val->type = arg->type; |
| 553 | VALUE_LVAL (val) = VALUE_LVAL (arg); |
| 554 | VALUE_ADDRESS (val) = VALUE_ADDRESS (arg); |
| 555 | val->offset = arg->offset; |
| 556 | val->bitpos = arg->bitpos; |
| 557 | val->bitsize = arg->bitsize; |
| 558 | VALUE_FRAME_ID (val) = VALUE_FRAME_ID (arg); |
| 559 | VALUE_REGNUM (val) = VALUE_REGNUM (arg); |
| 560 | val->lazy = arg->lazy; |
| 561 | val->optimized_out = arg->optimized_out; |
| 562 | val->embedded_offset = value_embedded_offset (arg); |
| 563 | val->pointed_to_offset = arg->pointed_to_offset; |
| 564 | val->modifiable = arg->modifiable; |
| 565 | if (!value_lazy (val)) |
| 566 | { |
| 567 | memcpy (value_contents_all_raw (val), value_contents_all_raw (arg), |
| 568 | TYPE_LENGTH (value_enclosing_type (arg))); |
| 569 | |
| 570 | } |
| 571 | return val; |
| 572 | } |
| 573 | \f |
| 574 | /* Access to the value history. */ |
| 575 | |
| 576 | /* Record a new value in the value history. |
| 577 | Returns the absolute history index of the entry. |
| 578 | Result of -1 indicates the value was not saved; otherwise it is the |
| 579 | value history index of this new item. */ |
| 580 | |
| 581 | int |
| 582 | record_latest_value (struct value *val) |
| 583 | { |
| 584 | int i; |
| 585 | |
| 586 | /* We don't want this value to have anything to do with the inferior anymore. |
| 587 | In particular, "set $1 = 50" should not affect the variable from which |
| 588 | the value was taken, and fast watchpoints should be able to assume that |
| 589 | a value on the value history never changes. */ |
| 590 | if (value_lazy (val)) |
| 591 | value_fetch_lazy (val); |
| 592 | /* We preserve VALUE_LVAL so that the user can find out where it was fetched |
| 593 | from. This is a bit dubious, because then *&$1 does not just return $1 |
| 594 | but the current contents of that location. c'est la vie... */ |
| 595 | val->modifiable = 0; |
| 596 | release_value (val); |
| 597 | |
| 598 | /* Here we treat value_history_count as origin-zero |
| 599 | and applying to the value being stored now. */ |
| 600 | |
| 601 | i = value_history_count % VALUE_HISTORY_CHUNK; |
| 602 | if (i == 0) |
| 603 | { |
| 604 | struct value_history_chunk *new |
| 605 | = (struct value_history_chunk *) |
| 606 | xmalloc (sizeof (struct value_history_chunk)); |
| 607 | memset (new->values, 0, sizeof new->values); |
| 608 | new->next = value_history_chain; |
| 609 | value_history_chain = new; |
| 610 | } |
| 611 | |
| 612 | value_history_chain->values[i] = val; |
| 613 | |
| 614 | /* Now we regard value_history_count as origin-one |
| 615 | and applying to the value just stored. */ |
| 616 | |
| 617 | return ++value_history_count; |
| 618 | } |
| 619 | |
| 620 | /* Return a copy of the value in the history with sequence number NUM. */ |
| 621 | |
| 622 | struct value * |
| 623 | access_value_history (int num) |
| 624 | { |
| 625 | struct value_history_chunk *chunk; |
| 626 | int i; |
| 627 | int absnum = num; |
| 628 | |
| 629 | if (absnum <= 0) |
| 630 | absnum += value_history_count; |
| 631 | |
| 632 | if (absnum <= 0) |
| 633 | { |
| 634 | if (num == 0) |
| 635 | error (_("The history is empty.")); |
| 636 | else if (num == 1) |
| 637 | error (_("There is only one value in the history.")); |
| 638 | else |
| 639 | error (_("History does not go back to $$%d."), -num); |
| 640 | } |
| 641 | if (absnum > value_history_count) |
| 642 | error (_("History has not yet reached $%d."), absnum); |
| 643 | |
| 644 | absnum--; |
| 645 | |
| 646 | /* Now absnum is always absolute and origin zero. */ |
| 647 | |
| 648 | chunk = value_history_chain; |
| 649 | for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; |
| 650 | i > 0; i--) |
| 651 | chunk = chunk->next; |
| 652 | |
| 653 | return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); |
| 654 | } |
| 655 | |
| 656 | /* Clear the value history entirely. |
| 657 | Must be done when new symbol tables are loaded, |
| 658 | because the type pointers become invalid. */ |
| 659 | |
| 660 | void |
| 661 | clear_value_history (void) |
| 662 | { |
| 663 | struct value_history_chunk *next; |
| 664 | int i; |
| 665 | struct value *val; |
| 666 | |
| 667 | while (value_history_chain) |
| 668 | { |
| 669 | for (i = 0; i < VALUE_HISTORY_CHUNK; i++) |
| 670 | if ((val = value_history_chain->values[i]) != NULL) |
| 671 | xfree (val); |
| 672 | next = value_history_chain->next; |
| 673 | xfree (value_history_chain); |
| 674 | value_history_chain = next; |
| 675 | } |
| 676 | value_history_count = 0; |
| 677 | } |
| 678 | |
| 679 | static void |
| 680 | show_values (char *num_exp, int from_tty) |
| 681 | { |
| 682 | int i; |
| 683 | struct value *val; |
| 684 | static int num = 1; |
| 685 | |
| 686 | if (num_exp) |
| 687 | { |
| 688 | /* "info history +" should print from the stored position. |
| 689 | "info history <exp>" should print around value number <exp>. */ |
| 690 | if (num_exp[0] != '+' || num_exp[1] != '\0') |
| 691 | num = parse_and_eval_long (num_exp) - 5; |
| 692 | } |
| 693 | else |
| 694 | { |
| 695 | /* "info history" means print the last 10 values. */ |
| 696 | num = value_history_count - 9; |
| 697 | } |
| 698 | |
| 699 | if (num <= 0) |
| 700 | num = 1; |
| 701 | |
| 702 | for (i = num; i < num + 10 && i <= value_history_count; i++) |
| 703 | { |
| 704 | val = access_value_history (i); |
| 705 | printf_filtered (("$%d = "), i); |
| 706 | value_print (val, gdb_stdout, 0, Val_pretty_default); |
| 707 | printf_filtered (("\n")); |
| 708 | } |
| 709 | |
| 710 | /* The next "info history +" should start after what we just printed. */ |
| 711 | num += 10; |
| 712 | |
| 713 | /* Hitting just return after this command should do the same thing as |
| 714 | "info history +". If num_exp is null, this is unnecessary, since |
| 715 | "info history +" is not useful after "info history". */ |
| 716 | if (from_tty && num_exp) |
| 717 | { |
| 718 | num_exp[0] = '+'; |
| 719 | num_exp[1] = '\0'; |
| 720 | } |
| 721 | } |
| 722 | \f |
| 723 | /* Internal variables. These are variables within the debugger |
| 724 | that hold values assigned by debugger commands. |
| 725 | The user refers to them with a '$' prefix |
| 726 | that does not appear in the variable names stored internally. */ |
| 727 | |
| 728 | static struct internalvar *internalvars; |
| 729 | |
| 730 | /* Look up an internal variable with name NAME. NAME should not |
| 731 | normally include a dollar sign. |
| 732 | |
| 733 | If the specified internal variable does not exist, |
| 734 | one is created, with a void value. */ |
| 735 | |
| 736 | struct internalvar * |
| 737 | lookup_internalvar (char *name) |
| 738 | { |
| 739 | struct internalvar *var; |
| 740 | |
| 741 | for (var = internalvars; var; var = var->next) |
| 742 | if (strcmp (var->name, name) == 0) |
| 743 | return var; |
| 744 | |
| 745 | var = (struct internalvar *) xmalloc (sizeof (struct internalvar)); |
| 746 | var->name = concat (name, NULL); |
| 747 | var->value = allocate_value (builtin_type_void); |
| 748 | release_value (var->value); |
| 749 | var->next = internalvars; |
| 750 | internalvars = var; |
| 751 | return var; |
| 752 | } |
| 753 | |
| 754 | struct value * |
| 755 | value_of_internalvar (struct internalvar *var) |
| 756 | { |
| 757 | struct value *val; |
| 758 | |
| 759 | val = value_copy (var->value); |
| 760 | if (value_lazy (val)) |
| 761 | value_fetch_lazy (val); |
| 762 | VALUE_LVAL (val) = lval_internalvar; |
| 763 | VALUE_INTERNALVAR (val) = var; |
| 764 | return val; |
| 765 | } |
| 766 | |
| 767 | void |
| 768 | set_internalvar_component (struct internalvar *var, int offset, int bitpos, |
| 769 | int bitsize, struct value *newval) |
| 770 | { |
| 771 | gdb_byte *addr = value_contents_writeable (var->value) + offset; |
| 772 | |
| 773 | if (bitsize) |
| 774 | modify_field (addr, value_as_long (newval), |
| 775 | bitpos, bitsize); |
| 776 | else |
| 777 | memcpy (addr, value_contents (newval), TYPE_LENGTH (value_type (newval))); |
| 778 | } |
| 779 | |
| 780 | void |
| 781 | set_internalvar (struct internalvar *var, struct value *val) |
| 782 | { |
| 783 | struct value *newval; |
| 784 | |
| 785 | newval = value_copy (val); |
| 786 | newval->modifiable = 1; |
| 787 | |
| 788 | /* Force the value to be fetched from the target now, to avoid problems |
| 789 | later when this internalvar is referenced and the target is gone or |
| 790 | has changed. */ |
| 791 | if (value_lazy (newval)) |
| 792 | value_fetch_lazy (newval); |
| 793 | |
| 794 | /* Begin code which must not call error(). If var->value points to |
| 795 | something free'd, an error() obviously leaves a dangling pointer. |
| 796 | But we also get a danling pointer if var->value points to |
| 797 | something in the value chain (i.e., before release_value is |
| 798 | called), because after the error free_all_values will get called before |
| 799 | long. */ |
| 800 | xfree (var->value); |
| 801 | var->value = newval; |
| 802 | release_value (newval); |
| 803 | /* End code which must not call error(). */ |
| 804 | } |
| 805 | |
| 806 | char * |
| 807 | internalvar_name (struct internalvar *var) |
| 808 | { |
| 809 | return var->name; |
| 810 | } |
| 811 | |
| 812 | /* Free all internalvars. Done when new symtabs are loaded, |
| 813 | because that makes the values invalid. */ |
| 814 | |
| 815 | void |
| 816 | clear_internalvars (void) |
| 817 | { |
| 818 | struct internalvar *var; |
| 819 | |
| 820 | while (internalvars) |
| 821 | { |
| 822 | var = internalvars; |
| 823 | internalvars = var->next; |
| 824 | xfree (var->name); |
| 825 | xfree (var->value); |
| 826 | xfree (var); |
| 827 | } |
| 828 | } |
| 829 | |
| 830 | static void |
| 831 | show_convenience (char *ignore, int from_tty) |
| 832 | { |
| 833 | struct internalvar *var; |
| 834 | int varseen = 0; |
| 835 | |
| 836 | for (var = internalvars; var; var = var->next) |
| 837 | { |
| 838 | if (!varseen) |
| 839 | { |
| 840 | varseen = 1; |
| 841 | } |
| 842 | printf_filtered (("$%s = "), var->name); |
| 843 | value_print (var->value, gdb_stdout, 0, Val_pretty_default); |
| 844 | printf_filtered (("\n")); |
| 845 | } |
| 846 | if (!varseen) |
| 847 | printf_unfiltered (_("\ |
| 848 | No debugger convenience variables now defined.\n\ |
| 849 | Convenience variables have names starting with \"$\";\n\ |
| 850 | use \"set\" as in \"set $foo = 5\" to define them.\n")); |
| 851 | } |
| 852 | \f |
| 853 | /* Extract a value as a C number (either long or double). |
| 854 | Knows how to convert fixed values to double, or |
| 855 | floating values to long. |
| 856 | Does not deallocate the value. */ |
| 857 | |
| 858 | LONGEST |
| 859 | value_as_long (struct value *val) |
| 860 | { |
| 861 | /* This coerces arrays and functions, which is necessary (e.g. |
| 862 | in disassemble_command). It also dereferences references, which |
| 863 | I suspect is the most logical thing to do. */ |
| 864 | val = coerce_array (val); |
| 865 | return unpack_long (value_type (val), value_contents (val)); |
| 866 | } |
| 867 | |
| 868 | DOUBLEST |
| 869 | value_as_double (struct value *val) |
| 870 | { |
| 871 | DOUBLEST foo; |
| 872 | int inv; |
| 873 | |
| 874 | foo = unpack_double (value_type (val), value_contents (val), &inv); |
| 875 | if (inv) |
| 876 | error (_("Invalid floating value found in program.")); |
| 877 | return foo; |
| 878 | } |
| 879 | /* Extract a value as a C pointer. Does not deallocate the value. |
| 880 | Note that val's type may not actually be a pointer; value_as_long |
| 881 | handles all the cases. */ |
| 882 | CORE_ADDR |
| 883 | value_as_address (struct value *val) |
| 884 | { |
| 885 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 886 | whether we want this to be true eventually. */ |
| 887 | #if 0 |
| 888 | /* ADDR_BITS_REMOVE is wrong if we are being called for a |
| 889 | non-address (e.g. argument to "signal", "info break", etc.), or |
| 890 | for pointers to char, in which the low bits *are* significant. */ |
| 891 | return ADDR_BITS_REMOVE (value_as_long (val)); |
| 892 | #else |
| 893 | |
| 894 | /* There are several targets (IA-64, PowerPC, and others) which |
| 895 | don't represent pointers to functions as simply the address of |
| 896 | the function's entry point. For example, on the IA-64, a |
| 897 | function pointer points to a two-word descriptor, generated by |
| 898 | the linker, which contains the function's entry point, and the |
| 899 | value the IA-64 "global pointer" register should have --- to |
| 900 | support position-independent code. The linker generates |
| 901 | descriptors only for those functions whose addresses are taken. |
| 902 | |
| 903 | On such targets, it's difficult for GDB to convert an arbitrary |
| 904 | function address into a function pointer; it has to either find |
| 905 | an existing descriptor for that function, or call malloc and |
| 906 | build its own. On some targets, it is impossible for GDB to |
| 907 | build a descriptor at all: the descriptor must contain a jump |
| 908 | instruction; data memory cannot be executed; and code memory |
| 909 | cannot be modified. |
| 910 | |
| 911 | Upon entry to this function, if VAL is a value of type `function' |
| 912 | (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then |
| 913 | VALUE_ADDRESS (val) is the address of the function. This is what |
| 914 | you'll get if you evaluate an expression like `main'. The call |
| 915 | to COERCE_ARRAY below actually does all the usual unary |
| 916 | conversions, which includes converting values of type `function' |
| 917 | to `pointer to function'. This is the challenging conversion |
| 918 | discussed above. Then, `unpack_long' will convert that pointer |
| 919 | back into an address. |
| 920 | |
| 921 | So, suppose the user types `disassemble foo' on an architecture |
| 922 | with a strange function pointer representation, on which GDB |
| 923 | cannot build its own descriptors, and suppose further that `foo' |
| 924 | has no linker-built descriptor. The address->pointer conversion |
| 925 | will signal an error and prevent the command from running, even |
| 926 | though the next step would have been to convert the pointer |
| 927 | directly back into the same address. |
| 928 | |
| 929 | The following shortcut avoids this whole mess. If VAL is a |
| 930 | function, just return its address directly. */ |
| 931 | if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC |
| 932 | || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD) |
| 933 | return VALUE_ADDRESS (val); |
| 934 | |
| 935 | val = coerce_array (val); |
| 936 | |
| 937 | /* Some architectures (e.g. Harvard), map instruction and data |
| 938 | addresses onto a single large unified address space. For |
| 939 | instance: An architecture may consider a large integer in the |
| 940 | range 0x10000000 .. 0x1000ffff to already represent a data |
| 941 | addresses (hence not need a pointer to address conversion) while |
| 942 | a small integer would still need to be converted integer to |
| 943 | pointer to address. Just assume such architectures handle all |
| 944 | integer conversions in a single function. */ |
| 945 | |
| 946 | /* JimB writes: |
| 947 | |
| 948 | I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we |
| 949 | must admonish GDB hackers to make sure its behavior matches the |
| 950 | compiler's, whenever possible. |
| 951 | |
| 952 | In general, I think GDB should evaluate expressions the same way |
| 953 | the compiler does. When the user copies an expression out of |
| 954 | their source code and hands it to a `print' command, they should |
| 955 | get the same value the compiler would have computed. Any |
| 956 | deviation from this rule can cause major confusion and annoyance, |
| 957 | and needs to be justified carefully. In other words, GDB doesn't |
| 958 | really have the freedom to do these conversions in clever and |
| 959 | useful ways. |
| 960 | |
| 961 | AndrewC pointed out that users aren't complaining about how GDB |
| 962 | casts integers to pointers; they are complaining that they can't |
| 963 | take an address from a disassembly listing and give it to `x/i'. |
| 964 | This is certainly important. |
| 965 | |
| 966 | Adding an architecture method like integer_to_address() certainly |
| 967 | makes it possible for GDB to "get it right" in all circumstances |
| 968 | --- the target has complete control over how things get done, so |
| 969 | people can Do The Right Thing for their target without breaking |
| 970 | anyone else. The standard doesn't specify how integers get |
| 971 | converted to pointers; usually, the ABI doesn't either, but |
| 972 | ABI-specific code is a more reasonable place to handle it. */ |
| 973 | |
| 974 | if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR |
| 975 | && TYPE_CODE (value_type (val)) != TYPE_CODE_REF |
| 976 | && gdbarch_integer_to_address_p (current_gdbarch)) |
| 977 | return gdbarch_integer_to_address (current_gdbarch, value_type (val), |
| 978 | value_contents (val)); |
| 979 | |
| 980 | return unpack_long (value_type (val), value_contents (val)); |
| 981 | #endif |
| 982 | } |
| 983 | \f |
| 984 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| 985 | as a long, or as a double, assuming the raw data is described |
| 986 | by type TYPE. Knows how to convert different sizes of values |
| 987 | and can convert between fixed and floating point. We don't assume |
| 988 | any alignment for the raw data. Return value is in host byte order. |
| 989 | |
| 990 | If you want functions and arrays to be coerced to pointers, and |
| 991 | references to be dereferenced, call value_as_long() instead. |
| 992 | |
| 993 | C++: It is assumed that the front-end has taken care of |
| 994 | all matters concerning pointers to members. A pointer |
| 995 | to member which reaches here is considered to be equivalent |
| 996 | to an INT (or some size). After all, it is only an offset. */ |
| 997 | |
| 998 | LONGEST |
| 999 | unpack_long (struct type *type, const gdb_byte *valaddr) |
| 1000 | { |
| 1001 | enum type_code code = TYPE_CODE (type); |
| 1002 | int len = TYPE_LENGTH (type); |
| 1003 | int nosign = TYPE_UNSIGNED (type); |
| 1004 | |
| 1005 | if (current_language->la_language == language_scm |
| 1006 | && is_scmvalue_type (type)) |
| 1007 | return scm_unpack (type, valaddr, TYPE_CODE_INT); |
| 1008 | |
| 1009 | switch (code) |
| 1010 | { |
| 1011 | case TYPE_CODE_TYPEDEF: |
| 1012 | return unpack_long (check_typedef (type), valaddr); |
| 1013 | case TYPE_CODE_ENUM: |
| 1014 | case TYPE_CODE_BOOL: |
| 1015 | case TYPE_CODE_INT: |
| 1016 | case TYPE_CODE_CHAR: |
| 1017 | case TYPE_CODE_RANGE: |
| 1018 | if (nosign) |
| 1019 | return extract_unsigned_integer (valaddr, len); |
| 1020 | else |
| 1021 | return extract_signed_integer (valaddr, len); |
| 1022 | |
| 1023 | case TYPE_CODE_FLT: |
| 1024 | return extract_typed_floating (valaddr, type); |
| 1025 | |
| 1026 | case TYPE_CODE_PTR: |
| 1027 | case TYPE_CODE_REF: |
| 1028 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 1029 | whether we want this to be true eventually. */ |
| 1030 | return extract_typed_address (valaddr, type); |
| 1031 | |
| 1032 | case TYPE_CODE_MEMBER: |
| 1033 | error (_("not implemented: member types in unpack_long")); |
| 1034 | |
| 1035 | default: |
| 1036 | error (_("Value can't be converted to integer.")); |
| 1037 | } |
| 1038 | return 0; /* Placate lint. */ |
| 1039 | } |
| 1040 | |
| 1041 | /* Return a double value from the specified type and address. |
| 1042 | INVP points to an int which is set to 0 for valid value, |
| 1043 | 1 for invalid value (bad float format). In either case, |
| 1044 | the returned double is OK to use. Argument is in target |
| 1045 | format, result is in host format. */ |
| 1046 | |
| 1047 | DOUBLEST |
| 1048 | unpack_double (struct type *type, const gdb_byte *valaddr, int *invp) |
| 1049 | { |
| 1050 | enum type_code code; |
| 1051 | int len; |
| 1052 | int nosign; |
| 1053 | |
| 1054 | *invp = 0; /* Assume valid. */ |
| 1055 | CHECK_TYPEDEF (type); |
| 1056 | code = TYPE_CODE (type); |
| 1057 | len = TYPE_LENGTH (type); |
| 1058 | nosign = TYPE_UNSIGNED (type); |
| 1059 | if (code == TYPE_CODE_FLT) |
| 1060 | { |
| 1061 | /* NOTE: cagney/2002-02-19: There was a test here to see if the |
| 1062 | floating-point value was valid (using the macro |
| 1063 | INVALID_FLOAT). That test/macro have been removed. |
| 1064 | |
| 1065 | It turns out that only the VAX defined this macro and then |
| 1066 | only in a non-portable way. Fixing the portability problem |
| 1067 | wouldn't help since the VAX floating-point code is also badly |
| 1068 | bit-rotten. The target needs to add definitions for the |
| 1069 | methods TARGET_FLOAT_FORMAT and TARGET_DOUBLE_FORMAT - these |
| 1070 | exactly describe the target floating-point format. The |
| 1071 | problem here is that the corresponding floatformat_vax_f and |
| 1072 | floatformat_vax_d values these methods should be set to are |
| 1073 | also not defined either. Oops! |
| 1074 | |
| 1075 | Hopefully someone will add both the missing floatformat |
| 1076 | definitions and the new cases for floatformat_is_valid (). */ |
| 1077 | |
| 1078 | if (!floatformat_is_valid (floatformat_from_type (type), valaddr)) |
| 1079 | { |
| 1080 | *invp = 1; |
| 1081 | return 0.0; |
| 1082 | } |
| 1083 | |
| 1084 | return extract_typed_floating (valaddr, type); |
| 1085 | } |
| 1086 | else if (nosign) |
| 1087 | { |
| 1088 | /* Unsigned -- be sure we compensate for signed LONGEST. */ |
| 1089 | return (ULONGEST) unpack_long (type, valaddr); |
| 1090 | } |
| 1091 | else |
| 1092 | { |
| 1093 | /* Signed -- we are OK with unpack_long. */ |
| 1094 | return unpack_long (type, valaddr); |
| 1095 | } |
| 1096 | } |
| 1097 | |
| 1098 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| 1099 | as a CORE_ADDR, assuming the raw data is described by type TYPE. |
| 1100 | We don't assume any alignment for the raw data. Return value is in |
| 1101 | host byte order. |
| 1102 | |
| 1103 | If you want functions and arrays to be coerced to pointers, and |
| 1104 | references to be dereferenced, call value_as_address() instead. |
| 1105 | |
| 1106 | C++: It is assumed that the front-end has taken care of |
| 1107 | all matters concerning pointers to members. A pointer |
| 1108 | to member which reaches here is considered to be equivalent |
| 1109 | to an INT (or some size). After all, it is only an offset. */ |
| 1110 | |
| 1111 | CORE_ADDR |
| 1112 | unpack_pointer (struct type *type, const gdb_byte *valaddr) |
| 1113 | { |
| 1114 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 1115 | whether we want this to be true eventually. */ |
| 1116 | return unpack_long (type, valaddr); |
| 1117 | } |
| 1118 | |
| 1119 | \f |
| 1120 | /* Get the value of the FIELDN'th field (which must be static) of |
| 1121 | TYPE. Return NULL if the field doesn't exist or has been |
| 1122 | optimized out. */ |
| 1123 | |
| 1124 | struct value * |
| 1125 | value_static_field (struct type *type, int fieldno) |
| 1126 | { |
| 1127 | struct value *retval; |
| 1128 | |
| 1129 | if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno)) |
| 1130 | { |
| 1131 | retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
| 1132 | TYPE_FIELD_STATIC_PHYSADDR (type, fieldno)); |
| 1133 | } |
| 1134 | else |
| 1135 | { |
| 1136 | char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno); |
| 1137 | struct symbol *sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0, NULL); |
| 1138 | if (sym == NULL) |
| 1139 | { |
| 1140 | /* With some compilers, e.g. HP aCC, static data members are reported |
| 1141 | as non-debuggable symbols */ |
| 1142 | struct minimal_symbol *msym = lookup_minimal_symbol (phys_name, NULL, NULL); |
| 1143 | if (!msym) |
| 1144 | return NULL; |
| 1145 | else |
| 1146 | { |
| 1147 | retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
| 1148 | SYMBOL_VALUE_ADDRESS (msym)); |
| 1149 | } |
| 1150 | } |
| 1151 | else |
| 1152 | { |
| 1153 | /* SYM should never have a SYMBOL_CLASS which will require |
| 1154 | read_var_value to use the FRAME parameter. */ |
| 1155 | if (symbol_read_needs_frame (sym)) |
| 1156 | warning (_("static field's value depends on the current " |
| 1157 | "frame - bad debug info?")); |
| 1158 | retval = read_var_value (sym, NULL); |
| 1159 | } |
| 1160 | if (retval && VALUE_LVAL (retval) == lval_memory) |
| 1161 | SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), |
| 1162 | VALUE_ADDRESS (retval)); |
| 1163 | } |
| 1164 | return retval; |
| 1165 | } |
| 1166 | |
| 1167 | /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE. |
| 1168 | You have to be careful here, since the size of the data area for the value |
| 1169 | is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger |
| 1170 | than the old enclosing type, you have to allocate more space for the data. |
| 1171 | The return value is a pointer to the new version of this value structure. */ |
| 1172 | |
| 1173 | struct value * |
| 1174 | value_change_enclosing_type (struct value *val, struct type *new_encl_type) |
| 1175 | { |
| 1176 | if (TYPE_LENGTH (new_encl_type) <= TYPE_LENGTH (value_enclosing_type (val))) |
| 1177 | { |
| 1178 | val->enclosing_type = new_encl_type; |
| 1179 | return val; |
| 1180 | } |
| 1181 | else |
| 1182 | { |
| 1183 | struct value *new_val; |
| 1184 | struct value *prev; |
| 1185 | |
| 1186 | new_val = (struct value *) xrealloc (val, sizeof (struct value) + TYPE_LENGTH (new_encl_type)); |
| 1187 | |
| 1188 | new_val->enclosing_type = new_encl_type; |
| 1189 | |
| 1190 | /* We have to make sure this ends up in the same place in the value |
| 1191 | chain as the original copy, so it's clean-up behavior is the same. |
| 1192 | If the value has been released, this is a waste of time, but there |
| 1193 | is no way to tell that in advance, so... */ |
| 1194 | |
| 1195 | if (val != all_values) |
| 1196 | { |
| 1197 | for (prev = all_values; prev != NULL; prev = prev->next) |
| 1198 | { |
| 1199 | if (prev->next == val) |
| 1200 | { |
| 1201 | prev->next = new_val; |
| 1202 | break; |
| 1203 | } |
| 1204 | } |
| 1205 | } |
| 1206 | |
| 1207 | return new_val; |
| 1208 | } |
| 1209 | } |
| 1210 | |
| 1211 | /* Given a value ARG1 (offset by OFFSET bytes) |
| 1212 | of a struct or union type ARG_TYPE, |
| 1213 | extract and return the value of one of its (non-static) fields. |
| 1214 | FIELDNO says which field. */ |
| 1215 | |
| 1216 | struct value * |
| 1217 | value_primitive_field (struct value *arg1, int offset, |
| 1218 | int fieldno, struct type *arg_type) |
| 1219 | { |
| 1220 | struct value *v; |
| 1221 | struct type *type; |
| 1222 | |
| 1223 | CHECK_TYPEDEF (arg_type); |
| 1224 | type = TYPE_FIELD_TYPE (arg_type, fieldno); |
| 1225 | |
| 1226 | /* Handle packed fields */ |
| 1227 | |
| 1228 | if (TYPE_FIELD_BITSIZE (arg_type, fieldno)) |
| 1229 | { |
| 1230 | v = value_from_longest (type, |
| 1231 | unpack_field_as_long (arg_type, |
| 1232 | value_contents (arg1) |
| 1233 | + offset, |
| 1234 | fieldno)); |
| 1235 | v->bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8; |
| 1236 | v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno); |
| 1237 | v->offset = value_offset (arg1) + offset |
| 1238 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| 1239 | } |
| 1240 | else if (fieldno < TYPE_N_BASECLASSES (arg_type)) |
| 1241 | { |
| 1242 | /* This field is actually a base subobject, so preserve the |
| 1243 | entire object's contents for later references to virtual |
| 1244 | bases, etc. */ |
| 1245 | v = allocate_value (value_enclosing_type (arg1)); |
| 1246 | v->type = type; |
| 1247 | if (value_lazy (arg1)) |
| 1248 | set_value_lazy (v, 1); |
| 1249 | else |
| 1250 | memcpy (value_contents_all_raw (v), value_contents_all_raw (arg1), |
| 1251 | TYPE_LENGTH (value_enclosing_type (arg1))); |
| 1252 | v->offset = value_offset (arg1); |
| 1253 | v->embedded_offset = (offset + value_embedded_offset (arg1) |
| 1254 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8); |
| 1255 | } |
| 1256 | else |
| 1257 | { |
| 1258 | /* Plain old data member */ |
| 1259 | offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| 1260 | v = allocate_value (type); |
| 1261 | if (value_lazy (arg1)) |
| 1262 | set_value_lazy (v, 1); |
| 1263 | else |
| 1264 | memcpy (value_contents_raw (v), |
| 1265 | value_contents_raw (arg1) + offset, |
| 1266 | TYPE_LENGTH (type)); |
| 1267 | v->offset = (value_offset (arg1) + offset |
| 1268 | + value_embedded_offset (arg1)); |
| 1269 | } |
| 1270 | VALUE_LVAL (v) = VALUE_LVAL (arg1); |
| 1271 | if (VALUE_LVAL (arg1) == lval_internalvar) |
| 1272 | VALUE_LVAL (v) = lval_internalvar_component; |
| 1273 | VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1); |
| 1274 | VALUE_REGNUM (v) = VALUE_REGNUM (arg1); |
| 1275 | VALUE_FRAME_ID (v) = VALUE_FRAME_ID (arg1); |
| 1276 | /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| 1277 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */ |
| 1278 | return v; |
| 1279 | } |
| 1280 | |
| 1281 | /* Given a value ARG1 of a struct or union type, |
| 1282 | extract and return the value of one of its (non-static) fields. |
| 1283 | FIELDNO says which field. */ |
| 1284 | |
| 1285 | struct value * |
| 1286 | value_field (struct value *arg1, int fieldno) |
| 1287 | { |
| 1288 | return value_primitive_field (arg1, 0, fieldno, value_type (arg1)); |
| 1289 | } |
| 1290 | |
| 1291 | /* Return a non-virtual function as a value. |
| 1292 | F is the list of member functions which contains the desired method. |
| 1293 | J is an index into F which provides the desired method. |
| 1294 | |
| 1295 | We only use the symbol for its address, so be happy with either a |
| 1296 | full symbol or a minimal symbol. |
| 1297 | */ |
| 1298 | |
| 1299 | struct value * |
| 1300 | value_fn_field (struct value **arg1p, struct fn_field *f, int j, struct type *type, |
| 1301 | int offset) |
| 1302 | { |
| 1303 | struct value *v; |
| 1304 | struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); |
| 1305 | char *physname = TYPE_FN_FIELD_PHYSNAME (f, j); |
| 1306 | struct symbol *sym; |
| 1307 | struct minimal_symbol *msym; |
| 1308 | |
| 1309 | sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0, NULL); |
| 1310 | if (sym != NULL) |
| 1311 | { |
| 1312 | msym = NULL; |
| 1313 | } |
| 1314 | else |
| 1315 | { |
| 1316 | gdb_assert (sym == NULL); |
| 1317 | msym = lookup_minimal_symbol (physname, NULL, NULL); |
| 1318 | if (msym == NULL) |
| 1319 | return NULL; |
| 1320 | } |
| 1321 | |
| 1322 | v = allocate_value (ftype); |
| 1323 | if (sym) |
| 1324 | { |
| 1325 | VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); |
| 1326 | } |
| 1327 | else |
| 1328 | { |
| 1329 | VALUE_ADDRESS (v) = SYMBOL_VALUE_ADDRESS (msym); |
| 1330 | } |
| 1331 | |
| 1332 | if (arg1p) |
| 1333 | { |
| 1334 | if (type != value_type (*arg1p)) |
| 1335 | *arg1p = value_ind (value_cast (lookup_pointer_type (type), |
| 1336 | value_addr (*arg1p))); |
| 1337 | |
| 1338 | /* Move the `this' pointer according to the offset. |
| 1339 | VALUE_OFFSET (*arg1p) += offset; |
| 1340 | */ |
| 1341 | } |
| 1342 | |
| 1343 | return v; |
| 1344 | } |
| 1345 | |
| 1346 | \f |
| 1347 | /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at |
| 1348 | VALADDR. |
| 1349 | |
| 1350 | Extracting bits depends on endianness of the machine. Compute the |
| 1351 | number of least significant bits to discard. For big endian machines, |
| 1352 | we compute the total number of bits in the anonymous object, subtract |
| 1353 | off the bit count from the MSB of the object to the MSB of the |
| 1354 | bitfield, then the size of the bitfield, which leaves the LSB discard |
| 1355 | count. For little endian machines, the discard count is simply the |
| 1356 | number of bits from the LSB of the anonymous object to the LSB of the |
| 1357 | bitfield. |
| 1358 | |
| 1359 | If the field is signed, we also do sign extension. */ |
| 1360 | |
| 1361 | LONGEST |
| 1362 | unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno) |
| 1363 | { |
| 1364 | ULONGEST val; |
| 1365 | ULONGEST valmask; |
| 1366 | int bitpos = TYPE_FIELD_BITPOS (type, fieldno); |
| 1367 | int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); |
| 1368 | int lsbcount; |
| 1369 | struct type *field_type; |
| 1370 | |
| 1371 | val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val)); |
| 1372 | field_type = TYPE_FIELD_TYPE (type, fieldno); |
| 1373 | CHECK_TYPEDEF (field_type); |
| 1374 | |
| 1375 | /* Extract bits. See comment above. */ |
| 1376 | |
| 1377 | if (BITS_BIG_ENDIAN) |
| 1378 | lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize); |
| 1379 | else |
| 1380 | lsbcount = (bitpos % 8); |
| 1381 | val >>= lsbcount; |
| 1382 | |
| 1383 | /* If the field does not entirely fill a LONGEST, then zero the sign bits. |
| 1384 | If the field is signed, and is negative, then sign extend. */ |
| 1385 | |
| 1386 | if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val))) |
| 1387 | { |
| 1388 | valmask = (((ULONGEST) 1) << bitsize) - 1; |
| 1389 | val &= valmask; |
| 1390 | if (!TYPE_UNSIGNED (field_type)) |
| 1391 | { |
| 1392 | if (val & (valmask ^ (valmask >> 1))) |
| 1393 | { |
| 1394 | val |= ~valmask; |
| 1395 | } |
| 1396 | } |
| 1397 | } |
| 1398 | return (val); |
| 1399 | } |
| 1400 | |
| 1401 | /* Modify the value of a bitfield. ADDR points to a block of memory in |
| 1402 | target byte order; the bitfield starts in the byte pointed to. FIELDVAL |
| 1403 | is the desired value of the field, in host byte order. BITPOS and BITSIZE |
| 1404 | indicate which bits (in target bit order) comprise the bitfield. |
| 1405 | Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and |
| 1406 | 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */ |
| 1407 | |
| 1408 | void |
| 1409 | modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos, int bitsize) |
| 1410 | { |
| 1411 | ULONGEST oword; |
| 1412 | ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize); |
| 1413 | |
| 1414 | /* If a negative fieldval fits in the field in question, chop |
| 1415 | off the sign extension bits. */ |
| 1416 | if ((~fieldval & ~(mask >> 1)) == 0) |
| 1417 | fieldval &= mask; |
| 1418 | |
| 1419 | /* Warn if value is too big to fit in the field in question. */ |
| 1420 | if (0 != (fieldval & ~mask)) |
| 1421 | { |
| 1422 | /* FIXME: would like to include fieldval in the message, but |
| 1423 | we don't have a sprintf_longest. */ |
| 1424 | warning (_("Value does not fit in %d bits."), bitsize); |
| 1425 | |
| 1426 | /* Truncate it, otherwise adjoining fields may be corrupted. */ |
| 1427 | fieldval &= mask; |
| 1428 | } |
| 1429 | |
| 1430 | oword = extract_unsigned_integer (addr, sizeof oword); |
| 1431 | |
| 1432 | /* Shifting for bit field depends on endianness of the target machine. */ |
| 1433 | if (BITS_BIG_ENDIAN) |
| 1434 | bitpos = sizeof (oword) * 8 - bitpos - bitsize; |
| 1435 | |
| 1436 | oword &= ~(mask << bitpos); |
| 1437 | oword |= fieldval << bitpos; |
| 1438 | |
| 1439 | store_unsigned_integer (addr, sizeof oword, oword); |
| 1440 | } |
| 1441 | \f |
| 1442 | /* Convert C numbers into newly allocated values */ |
| 1443 | |
| 1444 | struct value * |
| 1445 | value_from_longest (struct type *type, LONGEST num) |
| 1446 | { |
| 1447 | struct value *val = allocate_value (type); |
| 1448 | enum type_code code; |
| 1449 | int len; |
| 1450 | retry: |
| 1451 | code = TYPE_CODE (type); |
| 1452 | len = TYPE_LENGTH (type); |
| 1453 | |
| 1454 | switch (code) |
| 1455 | { |
| 1456 | case TYPE_CODE_TYPEDEF: |
| 1457 | type = check_typedef (type); |
| 1458 | goto retry; |
| 1459 | case TYPE_CODE_INT: |
| 1460 | case TYPE_CODE_CHAR: |
| 1461 | case TYPE_CODE_ENUM: |
| 1462 | case TYPE_CODE_BOOL: |
| 1463 | case TYPE_CODE_RANGE: |
| 1464 | store_signed_integer (value_contents_raw (val), len, num); |
| 1465 | break; |
| 1466 | |
| 1467 | case TYPE_CODE_REF: |
| 1468 | case TYPE_CODE_PTR: |
| 1469 | store_typed_address (value_contents_raw (val), type, (CORE_ADDR) num); |
| 1470 | break; |
| 1471 | |
| 1472 | default: |
| 1473 | error (_("Unexpected type (%d) encountered for integer constant."), code); |
| 1474 | } |
| 1475 | return val; |
| 1476 | } |
| 1477 | |
| 1478 | |
| 1479 | /* Create a value representing a pointer of type TYPE to the address |
| 1480 | ADDR. */ |
| 1481 | struct value * |
| 1482 | value_from_pointer (struct type *type, CORE_ADDR addr) |
| 1483 | { |
| 1484 | struct value *val = allocate_value (type); |
| 1485 | store_typed_address (value_contents_raw (val), type, addr); |
| 1486 | return val; |
| 1487 | } |
| 1488 | |
| 1489 | |
| 1490 | /* Create a value for a string constant to be stored locally |
| 1491 | (not in the inferior's memory space, but in GDB memory). |
| 1492 | This is analogous to value_from_longest, which also does not |
| 1493 | use inferior memory. String shall NOT contain embedded nulls. */ |
| 1494 | |
| 1495 | struct value * |
| 1496 | value_from_string (char *ptr) |
| 1497 | { |
| 1498 | struct value *val; |
| 1499 | int len = strlen (ptr); |
| 1500 | int lowbound = current_language->string_lower_bound; |
| 1501 | struct type *string_char_type; |
| 1502 | struct type *rangetype; |
| 1503 | struct type *stringtype; |
| 1504 | |
| 1505 | rangetype = create_range_type ((struct type *) NULL, |
| 1506 | builtin_type_int, |
| 1507 | lowbound, len + lowbound - 1); |
| 1508 | string_char_type = language_string_char_type (current_language, |
| 1509 | current_gdbarch); |
| 1510 | stringtype = create_array_type ((struct type *) NULL, |
| 1511 | string_char_type, |
| 1512 | rangetype); |
| 1513 | val = allocate_value (stringtype); |
| 1514 | memcpy (value_contents_raw (val), ptr, len); |
| 1515 | return val; |
| 1516 | } |
| 1517 | |
| 1518 | struct value * |
| 1519 | value_from_double (struct type *type, DOUBLEST num) |
| 1520 | { |
| 1521 | struct value *val = allocate_value (type); |
| 1522 | struct type *base_type = check_typedef (type); |
| 1523 | enum type_code code = TYPE_CODE (base_type); |
| 1524 | int len = TYPE_LENGTH (base_type); |
| 1525 | |
| 1526 | if (code == TYPE_CODE_FLT) |
| 1527 | { |
| 1528 | store_typed_floating (value_contents_raw (val), base_type, num); |
| 1529 | } |
| 1530 | else |
| 1531 | error (_("Unexpected type encountered for floating constant.")); |
| 1532 | |
| 1533 | return val; |
| 1534 | } |
| 1535 | |
| 1536 | struct value * |
| 1537 | coerce_ref (struct value *arg) |
| 1538 | { |
| 1539 | struct type *value_type_arg_tmp = check_typedef (value_type (arg)); |
| 1540 | if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF) |
| 1541 | arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp), |
| 1542 | unpack_pointer (value_type (arg), |
| 1543 | value_contents (arg))); |
| 1544 | return arg; |
| 1545 | } |
| 1546 | |
| 1547 | struct value * |
| 1548 | coerce_array (struct value *arg) |
| 1549 | { |
| 1550 | arg = coerce_ref (arg); |
| 1551 | if (current_language->c_style_arrays |
| 1552 | && TYPE_CODE (value_type (arg)) == TYPE_CODE_ARRAY) |
| 1553 | arg = value_coerce_array (arg); |
| 1554 | if (TYPE_CODE (value_type (arg)) == TYPE_CODE_FUNC) |
| 1555 | arg = value_coerce_function (arg); |
| 1556 | return arg; |
| 1557 | } |
| 1558 | |
| 1559 | struct value * |
| 1560 | coerce_number (struct value *arg) |
| 1561 | { |
| 1562 | arg = coerce_array (arg); |
| 1563 | arg = coerce_enum (arg); |
| 1564 | return arg; |
| 1565 | } |
| 1566 | |
| 1567 | struct value * |
| 1568 | coerce_enum (struct value *arg) |
| 1569 | { |
| 1570 | if (TYPE_CODE (check_typedef (value_type (arg))) == TYPE_CODE_ENUM) |
| 1571 | arg = value_cast (builtin_type_unsigned_int, arg); |
| 1572 | return arg; |
| 1573 | } |
| 1574 | \f |
| 1575 | |
| 1576 | /* Should we use DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS instead of |
| 1577 | EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc and TYPE |
| 1578 | is the type (which is known to be struct, union or array). |
| 1579 | |
| 1580 | On most machines, the struct convention is used unless we are |
| 1581 | using gcc and the type is of a special size. */ |
| 1582 | /* As of about 31 Mar 93, GCC was changed to be compatible with the |
| 1583 | native compiler. GCC 2.3.3 was the last release that did it the |
| 1584 | old way. Since gcc2_compiled was not changed, we have no |
| 1585 | way to correctly win in all cases, so we just do the right thing |
| 1586 | for gcc1 and for gcc2 after this change. Thus it loses for gcc |
| 1587 | 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled |
| 1588 | would cause more chaos than dealing with some struct returns being |
| 1589 | handled wrong. */ |
| 1590 | /* NOTE: cagney/2004-06-13: Deleted check for "gcc_p". GCC 1.x is |
| 1591 | dead. */ |
| 1592 | |
| 1593 | int |
| 1594 | generic_use_struct_convention (int gcc_p, struct type *value_type) |
| 1595 | { |
| 1596 | return !(TYPE_LENGTH (value_type) == 1 |
| 1597 | || TYPE_LENGTH (value_type) == 2 |
| 1598 | || TYPE_LENGTH (value_type) == 4 |
| 1599 | || TYPE_LENGTH (value_type) == 8); |
| 1600 | } |
| 1601 | |
| 1602 | /* Return true if the function returning the specified type is using |
| 1603 | the convention of returning structures in memory (passing in the |
| 1604 | address as a hidden first parameter). GCC_P is nonzero if compiled |
| 1605 | with GCC. */ |
| 1606 | |
| 1607 | int |
| 1608 | using_struct_return (struct type *value_type, int gcc_p) |
| 1609 | { |
| 1610 | enum type_code code = TYPE_CODE (value_type); |
| 1611 | |
| 1612 | if (code == TYPE_CODE_ERROR) |
| 1613 | error (_("Function return type unknown.")); |
| 1614 | |
| 1615 | if (code == TYPE_CODE_VOID) |
| 1616 | /* A void return value is never in memory. See also corresponding |
| 1617 | code in "print_return_value". */ |
| 1618 | return 0; |
| 1619 | |
| 1620 | /* Probe the architecture for the return-value convention. */ |
| 1621 | return (gdbarch_return_value (current_gdbarch, value_type, |
| 1622 | NULL, NULL, NULL) |
| 1623 | != RETURN_VALUE_REGISTER_CONVENTION); |
| 1624 | } |
| 1625 | |
| 1626 | void |
| 1627 | _initialize_values (void) |
| 1628 | { |
| 1629 | add_cmd ("convenience", no_class, show_convenience, _("\ |
| 1630 | Debugger convenience (\"$foo\") variables.\n\ |
| 1631 | These variables are created when you assign them values;\n\ |
| 1632 | thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\ |
| 1633 | \n\ |
| 1634 | A few convenience variables are given values automatically:\n\ |
| 1635 | \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\ |
| 1636 | \"$__\" holds the contents of the last address examined with \"x\"."), |
| 1637 | &showlist); |
| 1638 | |
| 1639 | add_cmd ("values", no_class, show_values, |
| 1640 | _("Elements of value history around item number IDX (or last ten)."), |
| 1641 | &showlist); |
| 1642 | } |