| 1 | /* Low level packing and unpacking of values for GDB, the GNU Debugger. |
| 2 | Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, |
| 3 | 1996, 1997, 1998, 1999, 2000 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 2 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program; if not, write to the Free Software |
| 20 | Foundation, Inc., 59 Temple Place - Suite 330, |
| 21 | Boston, MA 02111-1307, USA. */ |
| 22 | |
| 23 | #include "defs.h" |
| 24 | #include "gdb_string.h" |
| 25 | #include "symtab.h" |
| 26 | #include "gdbtypes.h" |
| 27 | #include "value.h" |
| 28 | #include "gdbcore.h" |
| 29 | #include "command.h" |
| 30 | #include "gdbcmd.h" |
| 31 | #include "target.h" |
| 32 | #include "language.h" |
| 33 | #include "scm-lang.h" |
| 34 | #include "demangle.h" |
| 35 | #include "doublest.h" |
| 36 | |
| 37 | /* Prototypes for exported functions. */ |
| 38 | |
| 39 | void _initialize_values (void); |
| 40 | |
| 41 | /* Prototypes for local functions. */ |
| 42 | |
| 43 | static value_ptr value_headof (value_ptr, struct type *, struct type *); |
| 44 | |
| 45 | static void show_values (char *, int); |
| 46 | |
| 47 | static void show_convenience (char *, int); |
| 48 | |
| 49 | |
| 50 | /* The value-history records all the values printed |
| 51 | by print commands during this session. Each chunk |
| 52 | records 60 consecutive values. The first chunk on |
| 53 | the chain records the most recent values. |
| 54 | The total number of values is in value_history_count. */ |
| 55 | |
| 56 | #define VALUE_HISTORY_CHUNK 60 |
| 57 | |
| 58 | struct value_history_chunk |
| 59 | { |
| 60 | struct value_history_chunk *next; |
| 61 | value_ptr values[VALUE_HISTORY_CHUNK]; |
| 62 | }; |
| 63 | |
| 64 | /* Chain of chunks now in use. */ |
| 65 | |
| 66 | static struct value_history_chunk *value_history_chain; |
| 67 | |
| 68 | static int value_history_count; /* Abs number of last entry stored */ |
| 69 | \f |
| 70 | /* List of all value objects currently allocated |
| 71 | (except for those released by calls to release_value) |
| 72 | This is so they can be freed after each command. */ |
| 73 | |
| 74 | static value_ptr all_values; |
| 75 | |
| 76 | /* Allocate a value that has the correct length for type TYPE. */ |
| 77 | |
| 78 | value_ptr |
| 79 | allocate_value (struct type *type) |
| 80 | { |
| 81 | register value_ptr val; |
| 82 | struct type *atype = check_typedef (type); |
| 83 | |
| 84 | val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype)); |
| 85 | VALUE_NEXT (val) = all_values; |
| 86 | all_values = val; |
| 87 | VALUE_TYPE (val) = type; |
| 88 | VALUE_ENCLOSING_TYPE (val) = type; |
| 89 | VALUE_LVAL (val) = not_lval; |
| 90 | VALUE_ADDRESS (val) = 0; |
| 91 | VALUE_FRAME (val) = 0; |
| 92 | VALUE_OFFSET (val) = 0; |
| 93 | VALUE_BITPOS (val) = 0; |
| 94 | VALUE_BITSIZE (val) = 0; |
| 95 | VALUE_REGNO (val) = -1; |
| 96 | VALUE_LAZY (val) = 0; |
| 97 | VALUE_OPTIMIZED_OUT (val) = 0; |
| 98 | VALUE_BFD_SECTION (val) = NULL; |
| 99 | VALUE_EMBEDDED_OFFSET (val) = 0; |
| 100 | VALUE_POINTED_TO_OFFSET (val) = 0; |
| 101 | val->modifiable = 1; |
| 102 | return val; |
| 103 | } |
| 104 | |
| 105 | /* Allocate a value that has the correct length |
| 106 | for COUNT repetitions type TYPE. */ |
| 107 | |
| 108 | value_ptr |
| 109 | allocate_repeat_value (struct type *type, int count) |
| 110 | { |
| 111 | int low_bound = current_language->string_lower_bound; /* ??? */ |
| 112 | /* FIXME-type-allocation: need a way to free this type when we are |
| 113 | done with it. */ |
| 114 | struct type *range_type |
| 115 | = create_range_type ((struct type *) NULL, builtin_type_int, |
| 116 | low_bound, count + low_bound - 1); |
| 117 | /* FIXME-type-allocation: need a way to free this type when we are |
| 118 | done with it. */ |
| 119 | return allocate_value (create_array_type ((struct type *) NULL, |
| 120 | type, range_type)); |
| 121 | } |
| 122 | |
| 123 | /* Return a mark in the value chain. All values allocated after the |
| 124 | mark is obtained (except for those released) are subject to being freed |
| 125 | if a subsequent value_free_to_mark is passed the mark. */ |
| 126 | value_ptr |
| 127 | value_mark (void) |
| 128 | { |
| 129 | return all_values; |
| 130 | } |
| 131 | |
| 132 | /* Free all values allocated since MARK was obtained by value_mark |
| 133 | (except for those released). */ |
| 134 | void |
| 135 | value_free_to_mark (value_ptr mark) |
| 136 | { |
| 137 | value_ptr val, next; |
| 138 | |
| 139 | for (val = all_values; val && val != mark; val = next) |
| 140 | { |
| 141 | next = VALUE_NEXT (val); |
| 142 | value_free (val); |
| 143 | } |
| 144 | all_values = val; |
| 145 | } |
| 146 | |
| 147 | /* Free all the values that have been allocated (except for those released). |
| 148 | Called after each command, successful or not. */ |
| 149 | |
| 150 | void |
| 151 | free_all_values (void) |
| 152 | { |
| 153 | register value_ptr val, next; |
| 154 | |
| 155 | for (val = all_values; val; val = next) |
| 156 | { |
| 157 | next = VALUE_NEXT (val); |
| 158 | value_free (val); |
| 159 | } |
| 160 | |
| 161 | all_values = 0; |
| 162 | } |
| 163 | |
| 164 | /* Remove VAL from the chain all_values |
| 165 | so it will not be freed automatically. */ |
| 166 | |
| 167 | void |
| 168 | release_value (register value_ptr val) |
| 169 | { |
| 170 | register value_ptr v; |
| 171 | |
| 172 | if (all_values == val) |
| 173 | { |
| 174 | all_values = val->next; |
| 175 | return; |
| 176 | } |
| 177 | |
| 178 | for (v = all_values; v; v = v->next) |
| 179 | { |
| 180 | if (v->next == val) |
| 181 | { |
| 182 | v->next = val->next; |
| 183 | break; |
| 184 | } |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /* Release all values up to mark */ |
| 189 | value_ptr |
| 190 | value_release_to_mark (value_ptr mark) |
| 191 | { |
| 192 | value_ptr val, next; |
| 193 | |
| 194 | for (val = next = all_values; next; next = VALUE_NEXT (next)) |
| 195 | if (VALUE_NEXT (next) == mark) |
| 196 | { |
| 197 | all_values = VALUE_NEXT (next); |
| 198 | VALUE_NEXT (next) = 0; |
| 199 | return val; |
| 200 | } |
| 201 | all_values = 0; |
| 202 | return val; |
| 203 | } |
| 204 | |
| 205 | /* Return a copy of the value ARG. |
| 206 | It contains the same contents, for same memory address, |
| 207 | but it's a different block of storage. */ |
| 208 | |
| 209 | value_ptr |
| 210 | value_copy (value_ptr arg) |
| 211 | { |
| 212 | register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg); |
| 213 | register value_ptr val = allocate_value (encl_type); |
| 214 | VALUE_TYPE (val) = VALUE_TYPE (arg); |
| 215 | VALUE_LVAL (val) = VALUE_LVAL (arg); |
| 216 | VALUE_ADDRESS (val) = VALUE_ADDRESS (arg); |
| 217 | VALUE_OFFSET (val) = VALUE_OFFSET (arg); |
| 218 | VALUE_BITPOS (val) = VALUE_BITPOS (arg); |
| 219 | VALUE_BITSIZE (val) = VALUE_BITSIZE (arg); |
| 220 | VALUE_FRAME (val) = VALUE_FRAME (arg); |
| 221 | VALUE_REGNO (val) = VALUE_REGNO (arg); |
| 222 | VALUE_LAZY (val) = VALUE_LAZY (arg); |
| 223 | VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg); |
| 224 | VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg); |
| 225 | VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg); |
| 226 | VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg); |
| 227 | val->modifiable = arg->modifiable; |
| 228 | if (!VALUE_LAZY (val)) |
| 229 | { |
| 230 | memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg), |
| 231 | TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg))); |
| 232 | |
| 233 | } |
| 234 | return val; |
| 235 | } |
| 236 | \f |
| 237 | /* Access to the value history. */ |
| 238 | |
| 239 | /* Record a new value in the value history. |
| 240 | Returns the absolute history index of the entry. |
| 241 | Result of -1 indicates the value was not saved; otherwise it is the |
| 242 | value history index of this new item. */ |
| 243 | |
| 244 | int |
| 245 | record_latest_value (value_ptr val) |
| 246 | { |
| 247 | int i; |
| 248 | |
| 249 | /* We don't want this value to have anything to do with the inferior anymore. |
| 250 | In particular, "set $1 = 50" should not affect the variable from which |
| 251 | the value was taken, and fast watchpoints should be able to assume that |
| 252 | a value on the value history never changes. */ |
| 253 | if (VALUE_LAZY (val)) |
| 254 | value_fetch_lazy (val); |
| 255 | /* We preserve VALUE_LVAL so that the user can find out where it was fetched |
| 256 | from. This is a bit dubious, because then *&$1 does not just return $1 |
| 257 | but the current contents of that location. c'est la vie... */ |
| 258 | val->modifiable = 0; |
| 259 | release_value (val); |
| 260 | |
| 261 | /* Here we treat value_history_count as origin-zero |
| 262 | and applying to the value being stored now. */ |
| 263 | |
| 264 | i = value_history_count % VALUE_HISTORY_CHUNK; |
| 265 | if (i == 0) |
| 266 | { |
| 267 | register struct value_history_chunk *new |
| 268 | = (struct value_history_chunk *) |
| 269 | xmalloc (sizeof (struct value_history_chunk)); |
| 270 | memset (new->values, 0, sizeof new->values); |
| 271 | new->next = value_history_chain; |
| 272 | value_history_chain = new; |
| 273 | } |
| 274 | |
| 275 | value_history_chain->values[i] = val; |
| 276 | |
| 277 | /* Now we regard value_history_count as origin-one |
| 278 | and applying to the value just stored. */ |
| 279 | |
| 280 | return ++value_history_count; |
| 281 | } |
| 282 | |
| 283 | /* Return a copy of the value in the history with sequence number NUM. */ |
| 284 | |
| 285 | value_ptr |
| 286 | access_value_history (int num) |
| 287 | { |
| 288 | register struct value_history_chunk *chunk; |
| 289 | register int i; |
| 290 | register int absnum = num; |
| 291 | |
| 292 | if (absnum <= 0) |
| 293 | absnum += value_history_count; |
| 294 | |
| 295 | if (absnum <= 0) |
| 296 | { |
| 297 | if (num == 0) |
| 298 | error ("The history is empty."); |
| 299 | else if (num == 1) |
| 300 | error ("There is only one value in the history."); |
| 301 | else |
| 302 | error ("History does not go back to $$%d.", -num); |
| 303 | } |
| 304 | if (absnum > value_history_count) |
| 305 | error ("History has not yet reached $%d.", absnum); |
| 306 | |
| 307 | absnum--; |
| 308 | |
| 309 | /* Now absnum is always absolute and origin zero. */ |
| 310 | |
| 311 | chunk = value_history_chain; |
| 312 | for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; |
| 313 | i > 0; i--) |
| 314 | chunk = chunk->next; |
| 315 | |
| 316 | return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); |
| 317 | } |
| 318 | |
| 319 | /* Clear the value history entirely. |
| 320 | Must be done when new symbol tables are loaded, |
| 321 | because the type pointers become invalid. */ |
| 322 | |
| 323 | void |
| 324 | clear_value_history (void) |
| 325 | { |
| 326 | register struct value_history_chunk *next; |
| 327 | register int i; |
| 328 | register value_ptr val; |
| 329 | |
| 330 | while (value_history_chain) |
| 331 | { |
| 332 | for (i = 0; i < VALUE_HISTORY_CHUNK; i++) |
| 333 | if ((val = value_history_chain->values[i]) != NULL) |
| 334 | xfree (val); |
| 335 | next = value_history_chain->next; |
| 336 | xfree (value_history_chain); |
| 337 | value_history_chain = next; |
| 338 | } |
| 339 | value_history_count = 0; |
| 340 | } |
| 341 | |
| 342 | static void |
| 343 | show_values (char *num_exp, int from_tty) |
| 344 | { |
| 345 | register int i; |
| 346 | register value_ptr val; |
| 347 | static int num = 1; |
| 348 | |
| 349 | if (num_exp) |
| 350 | { |
| 351 | /* "info history +" should print from the stored position. |
| 352 | "info history <exp>" should print around value number <exp>. */ |
| 353 | if (num_exp[0] != '+' || num_exp[1] != '\0') |
| 354 | num = parse_and_eval_long (num_exp) - 5; |
| 355 | } |
| 356 | else |
| 357 | { |
| 358 | /* "info history" means print the last 10 values. */ |
| 359 | num = value_history_count - 9; |
| 360 | } |
| 361 | |
| 362 | if (num <= 0) |
| 363 | num = 1; |
| 364 | |
| 365 | for (i = num; i < num + 10 && i <= value_history_count; i++) |
| 366 | { |
| 367 | val = access_value_history (i); |
| 368 | printf_filtered ("$%d = ", i); |
| 369 | value_print (val, gdb_stdout, 0, Val_pretty_default); |
| 370 | printf_filtered ("\n"); |
| 371 | } |
| 372 | |
| 373 | /* The next "info history +" should start after what we just printed. */ |
| 374 | num += 10; |
| 375 | |
| 376 | /* Hitting just return after this command should do the same thing as |
| 377 | "info history +". If num_exp is null, this is unnecessary, since |
| 378 | "info history +" is not useful after "info history". */ |
| 379 | if (from_tty && num_exp) |
| 380 | { |
| 381 | num_exp[0] = '+'; |
| 382 | num_exp[1] = '\0'; |
| 383 | } |
| 384 | } |
| 385 | \f |
| 386 | /* Internal variables. These are variables within the debugger |
| 387 | that hold values assigned by debugger commands. |
| 388 | The user refers to them with a '$' prefix |
| 389 | that does not appear in the variable names stored internally. */ |
| 390 | |
| 391 | static struct internalvar *internalvars; |
| 392 | |
| 393 | /* Look up an internal variable with name NAME. NAME should not |
| 394 | normally include a dollar sign. |
| 395 | |
| 396 | If the specified internal variable does not exist, |
| 397 | one is created, with a void value. */ |
| 398 | |
| 399 | struct internalvar * |
| 400 | lookup_internalvar (char *name) |
| 401 | { |
| 402 | register struct internalvar *var; |
| 403 | |
| 404 | for (var = internalvars; var; var = var->next) |
| 405 | if (STREQ (var->name, name)) |
| 406 | return var; |
| 407 | |
| 408 | var = (struct internalvar *) xmalloc (sizeof (struct internalvar)); |
| 409 | var->name = concat (name, NULL); |
| 410 | var->value = allocate_value (builtin_type_void); |
| 411 | release_value (var->value); |
| 412 | var->next = internalvars; |
| 413 | internalvars = var; |
| 414 | return var; |
| 415 | } |
| 416 | |
| 417 | value_ptr |
| 418 | value_of_internalvar (struct internalvar *var) |
| 419 | { |
| 420 | register value_ptr val; |
| 421 | |
| 422 | #ifdef IS_TRAPPED_INTERNALVAR |
| 423 | if (IS_TRAPPED_INTERNALVAR (var->name)) |
| 424 | return VALUE_OF_TRAPPED_INTERNALVAR (var); |
| 425 | #endif |
| 426 | |
| 427 | val = value_copy (var->value); |
| 428 | if (VALUE_LAZY (val)) |
| 429 | value_fetch_lazy (val); |
| 430 | VALUE_LVAL (val) = lval_internalvar; |
| 431 | VALUE_INTERNALVAR (val) = var; |
| 432 | return val; |
| 433 | } |
| 434 | |
| 435 | void |
| 436 | set_internalvar_component (struct internalvar *var, int offset, int bitpos, |
| 437 | int bitsize, value_ptr newval) |
| 438 | { |
| 439 | register char *addr = VALUE_CONTENTS (var->value) + offset; |
| 440 | |
| 441 | #ifdef IS_TRAPPED_INTERNALVAR |
| 442 | if (IS_TRAPPED_INTERNALVAR (var->name)) |
| 443 | SET_TRAPPED_INTERNALVAR (var, newval, bitpos, bitsize, offset); |
| 444 | #endif |
| 445 | |
| 446 | if (bitsize) |
| 447 | modify_field (addr, value_as_long (newval), |
| 448 | bitpos, bitsize); |
| 449 | else |
| 450 | memcpy (addr, VALUE_CONTENTS (newval), TYPE_LENGTH (VALUE_TYPE (newval))); |
| 451 | } |
| 452 | |
| 453 | void |
| 454 | set_internalvar (struct internalvar *var, value_ptr val) |
| 455 | { |
| 456 | value_ptr newval; |
| 457 | |
| 458 | #ifdef IS_TRAPPED_INTERNALVAR |
| 459 | if (IS_TRAPPED_INTERNALVAR (var->name)) |
| 460 | SET_TRAPPED_INTERNALVAR (var, val, 0, 0, 0); |
| 461 | #endif |
| 462 | |
| 463 | newval = value_copy (val); |
| 464 | newval->modifiable = 1; |
| 465 | |
| 466 | /* Force the value to be fetched from the target now, to avoid problems |
| 467 | later when this internalvar is referenced and the target is gone or |
| 468 | has changed. */ |
| 469 | if (VALUE_LAZY (newval)) |
| 470 | value_fetch_lazy (newval); |
| 471 | |
| 472 | /* Begin code which must not call error(). If var->value points to |
| 473 | something free'd, an error() obviously leaves a dangling pointer. |
| 474 | But we also get a danling pointer if var->value points to |
| 475 | something in the value chain (i.e., before release_value is |
| 476 | called), because after the error free_all_values will get called before |
| 477 | long. */ |
| 478 | xfree (var->value); |
| 479 | var->value = newval; |
| 480 | release_value (newval); |
| 481 | /* End code which must not call error(). */ |
| 482 | } |
| 483 | |
| 484 | char * |
| 485 | internalvar_name (struct internalvar *var) |
| 486 | { |
| 487 | return var->name; |
| 488 | } |
| 489 | |
| 490 | /* Free all internalvars. Done when new symtabs are loaded, |
| 491 | because that makes the values invalid. */ |
| 492 | |
| 493 | void |
| 494 | clear_internalvars (void) |
| 495 | { |
| 496 | register struct internalvar *var; |
| 497 | |
| 498 | while (internalvars) |
| 499 | { |
| 500 | var = internalvars; |
| 501 | internalvars = var->next; |
| 502 | xfree (var->name); |
| 503 | xfree (var->value); |
| 504 | xfree (var); |
| 505 | } |
| 506 | } |
| 507 | |
| 508 | static void |
| 509 | show_convenience (char *ignore, int from_tty) |
| 510 | { |
| 511 | register struct internalvar *var; |
| 512 | int varseen = 0; |
| 513 | |
| 514 | for (var = internalvars; var; var = var->next) |
| 515 | { |
| 516 | #ifdef IS_TRAPPED_INTERNALVAR |
| 517 | if (IS_TRAPPED_INTERNALVAR (var->name)) |
| 518 | continue; |
| 519 | #endif |
| 520 | if (!varseen) |
| 521 | { |
| 522 | varseen = 1; |
| 523 | } |
| 524 | printf_filtered ("$%s = ", var->name); |
| 525 | value_print (var->value, gdb_stdout, 0, Val_pretty_default); |
| 526 | printf_filtered ("\n"); |
| 527 | } |
| 528 | if (!varseen) |
| 529 | printf_unfiltered ("No debugger convenience variables now defined.\n\ |
| 530 | Convenience variables have names starting with \"$\";\n\ |
| 531 | use \"set\" as in \"set $foo = 5\" to define them.\n"); |
| 532 | } |
| 533 | \f |
| 534 | /* Extract a value as a C number (either long or double). |
| 535 | Knows how to convert fixed values to double, or |
| 536 | floating values to long. |
| 537 | Does not deallocate the value. */ |
| 538 | |
| 539 | LONGEST |
| 540 | value_as_long (register value_ptr val) |
| 541 | { |
| 542 | /* This coerces arrays and functions, which is necessary (e.g. |
| 543 | in disassemble_command). It also dereferences references, which |
| 544 | I suspect is the most logical thing to do. */ |
| 545 | COERCE_ARRAY (val); |
| 546 | return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| 547 | } |
| 548 | |
| 549 | DOUBLEST |
| 550 | value_as_double (register value_ptr val) |
| 551 | { |
| 552 | DOUBLEST foo; |
| 553 | int inv; |
| 554 | |
| 555 | foo = unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &inv); |
| 556 | if (inv) |
| 557 | error ("Invalid floating value found in program."); |
| 558 | return foo; |
| 559 | } |
| 560 | /* Extract a value as a C pointer. Does not deallocate the value. |
| 561 | Note that val's type may not actually be a pointer; value_as_long |
| 562 | handles all the cases. */ |
| 563 | CORE_ADDR |
| 564 | value_as_address (value_ptr val) |
| 565 | { |
| 566 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 567 | whether we want this to be true eventually. */ |
| 568 | #if 0 |
| 569 | /* ADDR_BITS_REMOVE is wrong if we are being called for a |
| 570 | non-address (e.g. argument to "signal", "info break", etc.), or |
| 571 | for pointers to char, in which the low bits *are* significant. */ |
| 572 | return ADDR_BITS_REMOVE (value_as_long (val)); |
| 573 | #else |
| 574 | |
| 575 | /* There are several targets (IA-64, PowerPC, and others) which |
| 576 | don't represent pointers to functions as simply the address of |
| 577 | the function's entry point. For example, on the IA-64, a |
| 578 | function pointer points to a two-word descriptor, generated by |
| 579 | the linker, which contains the function's entry point, and the |
| 580 | value the IA-64 "global pointer" register should have --- to |
| 581 | support position-independent code. The linker generates |
| 582 | descriptors only for those functions whose addresses are taken. |
| 583 | |
| 584 | On such targets, it's difficult for GDB to convert an arbitrary |
| 585 | function address into a function pointer; it has to either find |
| 586 | an existing descriptor for that function, or call malloc and |
| 587 | build its own. On some targets, it is impossible for GDB to |
| 588 | build a descriptor at all: the descriptor must contain a jump |
| 589 | instruction; data memory cannot be executed; and code memory |
| 590 | cannot be modified. |
| 591 | |
| 592 | Upon entry to this function, if VAL is a value of type `function' |
| 593 | (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then |
| 594 | VALUE_ADDRESS (val) is the address of the function. This is what |
| 595 | you'll get if you evaluate an expression like `main'. The call |
| 596 | to COERCE_ARRAY below actually does all the usual unary |
| 597 | conversions, which includes converting values of type `function' |
| 598 | to `pointer to function'. This is the challenging conversion |
| 599 | discussed above. Then, `unpack_long' will convert that pointer |
| 600 | back into an address. |
| 601 | |
| 602 | So, suppose the user types `disassemble foo' on an architecture |
| 603 | with a strange function pointer representation, on which GDB |
| 604 | cannot build its own descriptors, and suppose further that `foo' |
| 605 | has no linker-built descriptor. The address->pointer conversion |
| 606 | will signal an error and prevent the command from running, even |
| 607 | though the next step would have been to convert the pointer |
| 608 | directly back into the same address. |
| 609 | |
| 610 | The following shortcut avoids this whole mess. If VAL is a |
| 611 | function, just return its address directly. */ |
| 612 | if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC |
| 613 | || TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_METHOD) |
| 614 | return VALUE_ADDRESS (val); |
| 615 | |
| 616 | COERCE_ARRAY (val); |
| 617 | |
| 618 | /* Some architectures (e.g. Harvard), map instruction and data |
| 619 | addresses onto a single large unified address space. For |
| 620 | instance: An architecture may consider a large integer in the |
| 621 | range 0x10000000 .. 0x1000ffff to already represent a data |
| 622 | addresses (hence not need a pointer to address conversion) while |
| 623 | a small integer would still need to be converted integer to |
| 624 | pointer to address. Just assume such architectures handle all |
| 625 | integer conversions in a single function. */ |
| 626 | |
| 627 | /* JimB writes: |
| 628 | |
| 629 | I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we |
| 630 | must admonish GDB hackers to make sure its behavior matches the |
| 631 | compiler's, whenever possible. |
| 632 | |
| 633 | In general, I think GDB should evaluate expressions the same way |
| 634 | the compiler does. When the user copies an expression out of |
| 635 | their source code and hands it to a `print' command, they should |
| 636 | get the same value the compiler would have computed. Any |
| 637 | deviation from this rule can cause major confusion and annoyance, |
| 638 | and needs to be justified carefully. In other words, GDB doesn't |
| 639 | really have the freedom to do these conversions in clever and |
| 640 | useful ways. |
| 641 | |
| 642 | AndrewC pointed out that users aren't complaining about how GDB |
| 643 | casts integers to pointers; they are complaining that they can't |
| 644 | take an address from a disassembly listing and give it to `x/i'. |
| 645 | This is certainly important. |
| 646 | |
| 647 | Adding an architecture method like INTEGER_TO_ADDRESS certainly |
| 648 | makes it possible for GDB to "get it right" in all circumstances |
| 649 | --- the target has complete control over how things get done, so |
| 650 | people can Do The Right Thing for their target without breaking |
| 651 | anyone else. The standard doesn't specify how integers get |
| 652 | converted to pointers; usually, the ABI doesn't either, but |
| 653 | ABI-specific code is a more reasonable place to handle it. */ |
| 654 | |
| 655 | if (TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_PTR |
| 656 | && TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_REF |
| 657 | && INTEGER_TO_ADDRESS_P ()) |
| 658 | return INTEGER_TO_ADDRESS (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| 659 | |
| 660 | return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
| 661 | #endif |
| 662 | } |
| 663 | \f |
| 664 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| 665 | as a long, or as a double, assuming the raw data is described |
| 666 | by type TYPE. Knows how to convert different sizes of values |
| 667 | and can convert between fixed and floating point. We don't assume |
| 668 | any alignment for the raw data. Return value is in host byte order. |
| 669 | |
| 670 | If you want functions and arrays to be coerced to pointers, and |
| 671 | references to be dereferenced, call value_as_long() instead. |
| 672 | |
| 673 | C++: It is assumed that the front-end has taken care of |
| 674 | all matters concerning pointers to members. A pointer |
| 675 | to member which reaches here is considered to be equivalent |
| 676 | to an INT (or some size). After all, it is only an offset. */ |
| 677 | |
| 678 | LONGEST |
| 679 | unpack_long (struct type *type, char *valaddr) |
| 680 | { |
| 681 | register enum type_code code = TYPE_CODE (type); |
| 682 | register int len = TYPE_LENGTH (type); |
| 683 | register int nosign = TYPE_UNSIGNED (type); |
| 684 | |
| 685 | if (current_language->la_language == language_scm |
| 686 | && is_scmvalue_type (type)) |
| 687 | return scm_unpack (type, valaddr, TYPE_CODE_INT); |
| 688 | |
| 689 | switch (code) |
| 690 | { |
| 691 | case TYPE_CODE_TYPEDEF: |
| 692 | return unpack_long (check_typedef (type), valaddr); |
| 693 | case TYPE_CODE_ENUM: |
| 694 | case TYPE_CODE_BOOL: |
| 695 | case TYPE_CODE_INT: |
| 696 | case TYPE_CODE_CHAR: |
| 697 | case TYPE_CODE_RANGE: |
| 698 | if (nosign) |
| 699 | return extract_unsigned_integer (valaddr, len); |
| 700 | else |
| 701 | return extract_signed_integer (valaddr, len); |
| 702 | |
| 703 | case TYPE_CODE_FLT: |
| 704 | return extract_typed_floating (valaddr, type); |
| 705 | |
| 706 | case TYPE_CODE_PTR: |
| 707 | case TYPE_CODE_REF: |
| 708 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 709 | whether we want this to be true eventually. */ |
| 710 | return extract_typed_address (valaddr, type); |
| 711 | |
| 712 | case TYPE_CODE_MEMBER: |
| 713 | error ("not implemented: member types in unpack_long"); |
| 714 | |
| 715 | default: |
| 716 | error ("Value can't be converted to integer."); |
| 717 | } |
| 718 | return 0; /* Placate lint. */ |
| 719 | } |
| 720 | |
| 721 | /* Return a double value from the specified type and address. |
| 722 | INVP points to an int which is set to 0 for valid value, |
| 723 | 1 for invalid value (bad float format). In either case, |
| 724 | the returned double is OK to use. Argument is in target |
| 725 | format, result is in host format. */ |
| 726 | |
| 727 | DOUBLEST |
| 728 | unpack_double (struct type *type, char *valaddr, int *invp) |
| 729 | { |
| 730 | enum type_code code; |
| 731 | int len; |
| 732 | int nosign; |
| 733 | |
| 734 | *invp = 0; /* Assume valid. */ |
| 735 | CHECK_TYPEDEF (type); |
| 736 | code = TYPE_CODE (type); |
| 737 | len = TYPE_LENGTH (type); |
| 738 | nosign = TYPE_UNSIGNED (type); |
| 739 | if (code == TYPE_CODE_FLT) |
| 740 | { |
| 741 | #ifdef INVALID_FLOAT |
| 742 | if (INVALID_FLOAT (valaddr, len)) |
| 743 | { |
| 744 | *invp = 1; |
| 745 | return 1.234567891011121314; |
| 746 | } |
| 747 | #endif |
| 748 | return extract_typed_floating (valaddr, type); |
| 749 | } |
| 750 | else if (nosign) |
| 751 | { |
| 752 | /* Unsigned -- be sure we compensate for signed LONGEST. */ |
| 753 | return (ULONGEST) unpack_long (type, valaddr); |
| 754 | } |
| 755 | else |
| 756 | { |
| 757 | /* Signed -- we are OK with unpack_long. */ |
| 758 | return unpack_long (type, valaddr); |
| 759 | } |
| 760 | } |
| 761 | |
| 762 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR |
| 763 | as a CORE_ADDR, assuming the raw data is described by type TYPE. |
| 764 | We don't assume any alignment for the raw data. Return value is in |
| 765 | host byte order. |
| 766 | |
| 767 | If you want functions and arrays to be coerced to pointers, and |
| 768 | references to be dereferenced, call value_as_address() instead. |
| 769 | |
| 770 | C++: It is assumed that the front-end has taken care of |
| 771 | all matters concerning pointers to members. A pointer |
| 772 | to member which reaches here is considered to be equivalent |
| 773 | to an INT (or some size). After all, it is only an offset. */ |
| 774 | |
| 775 | CORE_ADDR |
| 776 | unpack_pointer (struct type *type, char *valaddr) |
| 777 | { |
| 778 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure |
| 779 | whether we want this to be true eventually. */ |
| 780 | return unpack_long (type, valaddr); |
| 781 | } |
| 782 | |
| 783 | \f |
| 784 | /* Get the value of the FIELDN'th field (which must be static) of TYPE. */ |
| 785 | |
| 786 | value_ptr |
| 787 | value_static_field (struct type *type, int fieldno) |
| 788 | { |
| 789 | CORE_ADDR addr; |
| 790 | asection *sect; |
| 791 | if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno)) |
| 792 | { |
| 793 | addr = TYPE_FIELD_STATIC_PHYSADDR (type, fieldno); |
| 794 | sect = NULL; |
| 795 | } |
| 796 | else |
| 797 | { |
| 798 | char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno); |
| 799 | struct symbol *sym = lookup_symbol (phys_name, 0, VAR_NAMESPACE, 0, NULL); |
| 800 | if (sym == NULL) |
| 801 | { |
| 802 | /* With some compilers, e.g. HP aCC, static data members are reported |
| 803 | as non-debuggable symbols */ |
| 804 | struct minimal_symbol *msym = lookup_minimal_symbol (phys_name, NULL, NULL); |
| 805 | if (!msym) |
| 806 | return NULL; |
| 807 | else |
| 808 | { |
| 809 | addr = SYMBOL_VALUE_ADDRESS (msym); |
| 810 | sect = SYMBOL_BFD_SECTION (msym); |
| 811 | } |
| 812 | } |
| 813 | else |
| 814 | { |
| 815 | /* Anything static that isn't a constant, has an address */ |
| 816 | if (SYMBOL_CLASS (sym) != LOC_CONST) |
| 817 | { |
| 818 | addr = SYMBOL_VALUE_ADDRESS (sym); |
| 819 | sect = SYMBOL_BFD_SECTION (sym); |
| 820 | } |
| 821 | /* However, static const's do not, the value is already known. */ |
| 822 | else |
| 823 | { |
| 824 | return value_from_longest (TYPE_FIELD_TYPE (type, fieldno), SYMBOL_VALUE (sym)); |
| 825 | } |
| 826 | } |
| 827 | SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), addr); |
| 828 | } |
| 829 | return value_at (TYPE_FIELD_TYPE (type, fieldno), addr, sect); |
| 830 | } |
| 831 | |
| 832 | /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE. |
| 833 | You have to be careful here, since the size of the data area for the value |
| 834 | is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger |
| 835 | than the old enclosing type, you have to allocate more space for the data. |
| 836 | The return value is a pointer to the new version of this value structure. */ |
| 837 | |
| 838 | value_ptr |
| 839 | value_change_enclosing_type (value_ptr val, struct type *new_encl_type) |
| 840 | { |
| 841 | if (TYPE_LENGTH (new_encl_type) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val))) |
| 842 | { |
| 843 | VALUE_ENCLOSING_TYPE (val) = new_encl_type; |
| 844 | return val; |
| 845 | } |
| 846 | else |
| 847 | { |
| 848 | value_ptr new_val; |
| 849 | register value_ptr prev; |
| 850 | |
| 851 | new_val = (value_ptr) xrealloc (val, sizeof (struct value) + TYPE_LENGTH (new_encl_type)); |
| 852 | |
| 853 | /* We have to make sure this ends up in the same place in the value |
| 854 | chain as the original copy, so it's clean-up behavior is the same. |
| 855 | If the value has been released, this is a waste of time, but there |
| 856 | is no way to tell that in advance, so... */ |
| 857 | |
| 858 | if (val != all_values) |
| 859 | { |
| 860 | for (prev = all_values; prev != NULL; prev = prev->next) |
| 861 | { |
| 862 | if (prev->next == val) |
| 863 | { |
| 864 | prev->next = new_val; |
| 865 | break; |
| 866 | } |
| 867 | } |
| 868 | } |
| 869 | |
| 870 | return new_val; |
| 871 | } |
| 872 | } |
| 873 | |
| 874 | /* Given a value ARG1 (offset by OFFSET bytes) |
| 875 | of a struct or union type ARG_TYPE, |
| 876 | extract and return the value of one of its (non-static) fields. |
| 877 | FIELDNO says which field. */ |
| 878 | |
| 879 | value_ptr |
| 880 | value_primitive_field (register value_ptr arg1, int offset, |
| 881 | register int fieldno, register struct type *arg_type) |
| 882 | { |
| 883 | register value_ptr v; |
| 884 | register struct type *type; |
| 885 | |
| 886 | CHECK_TYPEDEF (arg_type); |
| 887 | type = TYPE_FIELD_TYPE (arg_type, fieldno); |
| 888 | |
| 889 | /* Handle packed fields */ |
| 890 | |
| 891 | if (TYPE_FIELD_BITSIZE (arg_type, fieldno)) |
| 892 | { |
| 893 | v = value_from_longest (type, |
| 894 | unpack_field_as_long (arg_type, |
| 895 | VALUE_CONTENTS (arg1) |
| 896 | + offset, |
| 897 | fieldno)); |
| 898 | VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8; |
| 899 | VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno); |
| 900 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| 901 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| 902 | } |
| 903 | else if (fieldno < TYPE_N_BASECLASSES (arg_type)) |
| 904 | { |
| 905 | /* This field is actually a base subobject, so preserve the |
| 906 | entire object's contents for later references to virtual |
| 907 | bases, etc. */ |
| 908 | v = allocate_value (VALUE_ENCLOSING_TYPE (arg1)); |
| 909 | VALUE_TYPE (v) = type; |
| 910 | if (VALUE_LAZY (arg1)) |
| 911 | VALUE_LAZY (v) = 1; |
| 912 | else |
| 913 | memcpy (VALUE_CONTENTS_ALL_RAW (v), VALUE_CONTENTS_ALL_RAW (arg1), |
| 914 | TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1))); |
| 915 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1); |
| 916 | VALUE_EMBEDDED_OFFSET (v) |
| 917 | = offset + |
| 918 | VALUE_EMBEDDED_OFFSET (arg1) + |
| 919 | TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| 920 | } |
| 921 | else |
| 922 | { |
| 923 | /* Plain old data member */ |
| 924 | offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; |
| 925 | v = allocate_value (type); |
| 926 | if (VALUE_LAZY (arg1)) |
| 927 | VALUE_LAZY (v) = 1; |
| 928 | else |
| 929 | memcpy (VALUE_CONTENTS_RAW (v), |
| 930 | VALUE_CONTENTS_RAW (arg1) + offset, |
| 931 | TYPE_LENGTH (type)); |
| 932 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset; |
| 933 | } |
| 934 | VALUE_LVAL (v) = VALUE_LVAL (arg1); |
| 935 | if (VALUE_LVAL (arg1) == lval_internalvar) |
| 936 | VALUE_LVAL (v) = lval_internalvar_component; |
| 937 | VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1); |
| 938 | VALUE_REGNO (v) = VALUE_REGNO (arg1); |
| 939 | /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
| 940 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */ |
| 941 | return v; |
| 942 | } |
| 943 | |
| 944 | /* Given a value ARG1 of a struct or union type, |
| 945 | extract and return the value of one of its (non-static) fields. |
| 946 | FIELDNO says which field. */ |
| 947 | |
| 948 | value_ptr |
| 949 | value_field (register value_ptr arg1, register int fieldno) |
| 950 | { |
| 951 | return value_primitive_field (arg1, 0, fieldno, VALUE_TYPE (arg1)); |
| 952 | } |
| 953 | |
| 954 | /* Return a non-virtual function as a value. |
| 955 | F is the list of member functions which contains the desired method. |
| 956 | J is an index into F which provides the desired method. */ |
| 957 | |
| 958 | value_ptr |
| 959 | value_fn_field (value_ptr *arg1p, struct fn_field *f, int j, struct type *type, |
| 960 | int offset) |
| 961 | { |
| 962 | register value_ptr v; |
| 963 | register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); |
| 964 | struct symbol *sym; |
| 965 | |
| 966 | sym = lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j), |
| 967 | 0, VAR_NAMESPACE, 0, NULL); |
| 968 | if (!sym) |
| 969 | return NULL; |
| 970 | /* |
| 971 | error ("Internal error: could not find physical method named %s", |
| 972 | TYPE_FN_FIELD_PHYSNAME (f, j)); |
| 973 | */ |
| 974 | |
| 975 | v = allocate_value (ftype); |
| 976 | VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); |
| 977 | VALUE_TYPE (v) = ftype; |
| 978 | |
| 979 | if (arg1p) |
| 980 | { |
| 981 | if (type != VALUE_TYPE (*arg1p)) |
| 982 | *arg1p = value_ind (value_cast (lookup_pointer_type (type), |
| 983 | value_addr (*arg1p))); |
| 984 | |
| 985 | /* Move the `this' pointer according to the offset. |
| 986 | VALUE_OFFSET (*arg1p) += offset; |
| 987 | */ |
| 988 | } |
| 989 | |
| 990 | return v; |
| 991 | } |
| 992 | |
| 993 | /* ARG is a pointer to an object we know to be at least |
| 994 | a DTYPE. BTYPE is the most derived basetype that has |
| 995 | already been searched (and need not be searched again). |
| 996 | After looking at the vtables between BTYPE and DTYPE, |
| 997 | return the most derived type we find. The caller must |
| 998 | be satisfied when the return value == DTYPE. |
| 999 | |
| 1000 | FIXME-tiemann: should work with dossier entries as well. |
| 1001 | NOTICE - djb: I see no good reason at all to keep this function now that |
| 1002 | we have RTTI support. It's used in literally one place, and it's |
| 1003 | hard to keep this function up to date when it's purpose is served |
| 1004 | by value_rtti_type efficiently. |
| 1005 | Consider it gone for 5.1. */ |
| 1006 | |
| 1007 | static value_ptr |
| 1008 | value_headof (value_ptr in_arg, struct type *btype, struct type *dtype) |
| 1009 | { |
| 1010 | /* First collect the vtables we must look at for this object. */ |
| 1011 | value_ptr arg, vtbl; |
| 1012 | struct symbol *sym; |
| 1013 | char *demangled_name; |
| 1014 | struct minimal_symbol *msymbol; |
| 1015 | |
| 1016 | btype = TYPE_VPTR_BASETYPE (dtype); |
| 1017 | CHECK_TYPEDEF (btype); |
| 1018 | arg = in_arg; |
| 1019 | if (btype != dtype) |
| 1020 | arg = value_cast (lookup_pointer_type (btype), arg); |
| 1021 | if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_REF) |
| 1022 | { |
| 1023 | /* |
| 1024 | * Copy the value, but change the type from (T&) to (T*). |
| 1025 | * We keep the same location information, which is efficient, |
| 1026 | * and allows &(&X) to get the location containing the reference. |
| 1027 | */ |
| 1028 | arg = value_copy (arg); |
| 1029 | VALUE_TYPE (arg) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg))); |
| 1030 | } |
| 1031 | if (VALUE_ADDRESS(value_field (value_ind(arg), TYPE_VPTR_FIELDNO (btype)))==0) |
| 1032 | return arg; |
| 1033 | |
| 1034 | vtbl = value_ind (value_field (value_ind (arg), TYPE_VPTR_FIELDNO (btype))); |
| 1035 | /* Turn vtable into typeinfo function */ |
| 1036 | VALUE_OFFSET(vtbl)+=4; |
| 1037 | |
| 1038 | msymbol = lookup_minimal_symbol_by_pc ( value_as_address(value_ind(vtbl)) ); |
| 1039 | if (msymbol == NULL |
| 1040 | || (demangled_name = SYMBOL_NAME (msymbol)) == NULL) |
| 1041 | { |
| 1042 | /* If we expected to find a vtable, but did not, let the user |
| 1043 | know that we aren't happy, but don't throw an error. |
| 1044 | FIXME: there has to be a better way to do this. */ |
| 1045 | struct type *error_type = (struct type *) xmalloc (sizeof (struct type)); |
| 1046 | memcpy (error_type, VALUE_TYPE (in_arg), sizeof (struct type)); |
| 1047 | TYPE_NAME (error_type) = savestring ("suspicious *", sizeof ("suspicious *")); |
| 1048 | VALUE_TYPE (in_arg) = error_type; |
| 1049 | return in_arg; |
| 1050 | } |
| 1051 | demangled_name = cplus_demangle(demangled_name,DMGL_ANSI); |
| 1052 | *(strchr (demangled_name, ' ')) = '\0'; |
| 1053 | |
| 1054 | sym = lookup_symbol (demangled_name, 0, VAR_NAMESPACE, 0, 0); |
| 1055 | if (sym == NULL) |
| 1056 | error ("could not find type declaration for `%s'", demangled_name); |
| 1057 | |
| 1058 | arg = in_arg; |
| 1059 | VALUE_TYPE (arg) = lookup_pointer_type (SYMBOL_TYPE (sym)); |
| 1060 | return arg; |
| 1061 | } |
| 1062 | |
| 1063 | /* ARG is a pointer object of type TYPE. If TYPE has virtual |
| 1064 | function tables, probe ARG's tables (including the vtables |
| 1065 | of its baseclasses) to figure out the most derived type that ARG |
| 1066 | could actually be a pointer to. */ |
| 1067 | |
| 1068 | value_ptr |
| 1069 | value_from_vtable_info (value_ptr arg, struct type *type) |
| 1070 | { |
| 1071 | /* Take care of preliminaries. */ |
| 1072 | if (TYPE_VPTR_FIELDNO (type) < 0) |
| 1073 | fill_in_vptr_fieldno (type); |
| 1074 | if (TYPE_VPTR_FIELDNO (type) < 0) |
| 1075 | return 0; |
| 1076 | |
| 1077 | return value_headof (arg, 0, type); |
| 1078 | } |
| 1079 | |
| 1080 | /* Return true if the INDEXth field of TYPE is a virtual baseclass |
| 1081 | pointer which is for the base class whose type is BASECLASS. */ |
| 1082 | |
| 1083 | static int |
| 1084 | vb_match (struct type *type, int index, struct type *basetype) |
| 1085 | { |
| 1086 | struct type *fieldtype; |
| 1087 | char *name = TYPE_FIELD_NAME (type, index); |
| 1088 | char *field_class_name = NULL; |
| 1089 | |
| 1090 | if (*name != '_') |
| 1091 | return 0; |
| 1092 | /* gcc 2.4 uses _vb$. */ |
| 1093 | if (name[1] == 'v' && name[2] == 'b' && is_cplus_marker (name[3])) |
| 1094 | field_class_name = name + 4; |
| 1095 | /* gcc 2.5 will use __vb_. */ |
| 1096 | if (name[1] == '_' && name[2] == 'v' && name[3] == 'b' && name[4] == '_') |
| 1097 | field_class_name = name + 5; |
| 1098 | |
| 1099 | if (field_class_name == NULL) |
| 1100 | /* This field is not a virtual base class pointer. */ |
| 1101 | return 0; |
| 1102 | |
| 1103 | /* It's a virtual baseclass pointer, now we just need to find out whether |
| 1104 | it is for this baseclass. */ |
| 1105 | fieldtype = TYPE_FIELD_TYPE (type, index); |
| 1106 | if (fieldtype == NULL |
| 1107 | || TYPE_CODE (fieldtype) != TYPE_CODE_PTR) |
| 1108 | /* "Can't happen". */ |
| 1109 | return 0; |
| 1110 | |
| 1111 | /* What we check for is that either the types are equal (needed for |
| 1112 | nameless types) or have the same name. This is ugly, and a more |
| 1113 | elegant solution should be devised (which would probably just push |
| 1114 | the ugliness into symbol reading unless we change the stabs format). */ |
| 1115 | if (TYPE_TARGET_TYPE (fieldtype) == basetype) |
| 1116 | return 1; |
| 1117 | |
| 1118 | if (TYPE_NAME (basetype) != NULL |
| 1119 | && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)) != NULL |
| 1120 | && STREQ (TYPE_NAME (basetype), |
| 1121 | TYPE_NAME (TYPE_TARGET_TYPE (fieldtype)))) |
| 1122 | return 1; |
| 1123 | return 0; |
| 1124 | } |
| 1125 | |
| 1126 | /* Compute the offset of the baseclass which is |
| 1127 | the INDEXth baseclass of class TYPE, |
| 1128 | for value at VALADDR (in host) at ADDRESS (in target). |
| 1129 | The result is the offset of the baseclass value relative |
| 1130 | to (the address of)(ARG) + OFFSET. |
| 1131 | |
| 1132 | -1 is returned on error. */ |
| 1133 | |
| 1134 | int |
| 1135 | baseclass_offset (struct type *type, int index, char *valaddr, |
| 1136 | CORE_ADDR address) |
| 1137 | { |
| 1138 | struct type *basetype = TYPE_BASECLASS (type, index); |
| 1139 | |
| 1140 | if (BASETYPE_VIA_VIRTUAL (type, index)) |
| 1141 | { |
| 1142 | /* Must hunt for the pointer to this virtual baseclass. */ |
| 1143 | register int i, len = TYPE_NFIELDS (type); |
| 1144 | register int n_baseclasses = TYPE_N_BASECLASSES (type); |
| 1145 | |
| 1146 | /* First look for the virtual baseclass pointer |
| 1147 | in the fields. */ |
| 1148 | for (i = n_baseclasses; i < len; i++) |
| 1149 | { |
| 1150 | if (vb_match (type, i, basetype)) |
| 1151 | { |
| 1152 | CORE_ADDR addr |
| 1153 | = unpack_pointer (TYPE_FIELD_TYPE (type, i), |
| 1154 | valaddr + (TYPE_FIELD_BITPOS (type, i) / 8)); |
| 1155 | |
| 1156 | return addr - (LONGEST) address; |
| 1157 | } |
| 1158 | } |
| 1159 | /* Not in the fields, so try looking through the baseclasses. */ |
| 1160 | for (i = index + 1; i < n_baseclasses; i++) |
| 1161 | { |
| 1162 | int boffset = |
| 1163 | baseclass_offset (type, i, valaddr, address); |
| 1164 | if (boffset) |
| 1165 | return boffset; |
| 1166 | } |
| 1167 | /* Not found. */ |
| 1168 | return -1; |
| 1169 | } |
| 1170 | |
| 1171 | /* Baseclass is easily computed. */ |
| 1172 | return TYPE_BASECLASS_BITPOS (type, index) / 8; |
| 1173 | } |
| 1174 | \f |
| 1175 | /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at |
| 1176 | VALADDR. |
| 1177 | |
| 1178 | Extracting bits depends on endianness of the machine. Compute the |
| 1179 | number of least significant bits to discard. For big endian machines, |
| 1180 | we compute the total number of bits in the anonymous object, subtract |
| 1181 | off the bit count from the MSB of the object to the MSB of the |
| 1182 | bitfield, then the size of the bitfield, which leaves the LSB discard |
| 1183 | count. For little endian machines, the discard count is simply the |
| 1184 | number of bits from the LSB of the anonymous object to the LSB of the |
| 1185 | bitfield. |
| 1186 | |
| 1187 | If the field is signed, we also do sign extension. */ |
| 1188 | |
| 1189 | LONGEST |
| 1190 | unpack_field_as_long (struct type *type, char *valaddr, int fieldno) |
| 1191 | { |
| 1192 | ULONGEST val; |
| 1193 | ULONGEST valmask; |
| 1194 | int bitpos = TYPE_FIELD_BITPOS (type, fieldno); |
| 1195 | int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); |
| 1196 | int lsbcount; |
| 1197 | struct type *field_type; |
| 1198 | |
| 1199 | val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val)); |
| 1200 | field_type = TYPE_FIELD_TYPE (type, fieldno); |
| 1201 | CHECK_TYPEDEF (field_type); |
| 1202 | |
| 1203 | /* Extract bits. See comment above. */ |
| 1204 | |
| 1205 | if (BITS_BIG_ENDIAN) |
| 1206 | lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize); |
| 1207 | else |
| 1208 | lsbcount = (bitpos % 8); |
| 1209 | val >>= lsbcount; |
| 1210 | |
| 1211 | /* If the field does not entirely fill a LONGEST, then zero the sign bits. |
| 1212 | If the field is signed, and is negative, then sign extend. */ |
| 1213 | |
| 1214 | if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val))) |
| 1215 | { |
| 1216 | valmask = (((ULONGEST) 1) << bitsize) - 1; |
| 1217 | val &= valmask; |
| 1218 | if (!TYPE_UNSIGNED (field_type)) |
| 1219 | { |
| 1220 | if (val & (valmask ^ (valmask >> 1))) |
| 1221 | { |
| 1222 | val |= ~valmask; |
| 1223 | } |
| 1224 | } |
| 1225 | } |
| 1226 | return (val); |
| 1227 | } |
| 1228 | |
| 1229 | /* Modify the value of a bitfield. ADDR points to a block of memory in |
| 1230 | target byte order; the bitfield starts in the byte pointed to. FIELDVAL |
| 1231 | is the desired value of the field, in host byte order. BITPOS and BITSIZE |
| 1232 | indicate which bits (in target bit order) comprise the bitfield. */ |
| 1233 | |
| 1234 | void |
| 1235 | modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize) |
| 1236 | { |
| 1237 | LONGEST oword; |
| 1238 | |
| 1239 | /* If a negative fieldval fits in the field in question, chop |
| 1240 | off the sign extension bits. */ |
| 1241 | if (bitsize < (8 * (int) sizeof (fieldval)) |
| 1242 | && (~fieldval & ~((1 << (bitsize - 1)) - 1)) == 0) |
| 1243 | fieldval = fieldval & ((1 << bitsize) - 1); |
| 1244 | |
| 1245 | /* Warn if value is too big to fit in the field in question. */ |
| 1246 | if (bitsize < (8 * (int) sizeof (fieldval)) |
| 1247 | && 0 != (fieldval & ~((1 << bitsize) - 1))) |
| 1248 | { |
| 1249 | /* FIXME: would like to include fieldval in the message, but |
| 1250 | we don't have a sprintf_longest. */ |
| 1251 | warning ("Value does not fit in %d bits.", bitsize); |
| 1252 | |
| 1253 | /* Truncate it, otherwise adjoining fields may be corrupted. */ |
| 1254 | fieldval = fieldval & ((1 << bitsize) - 1); |
| 1255 | } |
| 1256 | |
| 1257 | oword = extract_signed_integer (addr, sizeof oword); |
| 1258 | |
| 1259 | /* Shifting for bit field depends on endianness of the target machine. */ |
| 1260 | if (BITS_BIG_ENDIAN) |
| 1261 | bitpos = sizeof (oword) * 8 - bitpos - bitsize; |
| 1262 | |
| 1263 | /* Mask out old value, while avoiding shifts >= size of oword */ |
| 1264 | if (bitsize < 8 * (int) sizeof (oword)) |
| 1265 | oword &= ~(((((ULONGEST) 1) << bitsize) - 1) << bitpos); |
| 1266 | else |
| 1267 | oword &= ~((~(ULONGEST) 0) << bitpos); |
| 1268 | oword |= fieldval << bitpos; |
| 1269 | |
| 1270 | store_signed_integer (addr, sizeof oword, oword); |
| 1271 | } |
| 1272 | \f |
| 1273 | /* Convert C numbers into newly allocated values */ |
| 1274 | |
| 1275 | value_ptr |
| 1276 | value_from_longest (struct type *type, register LONGEST num) |
| 1277 | { |
| 1278 | register value_ptr val = allocate_value (type); |
| 1279 | register enum type_code code; |
| 1280 | register int len; |
| 1281 | retry: |
| 1282 | code = TYPE_CODE (type); |
| 1283 | len = TYPE_LENGTH (type); |
| 1284 | |
| 1285 | switch (code) |
| 1286 | { |
| 1287 | case TYPE_CODE_TYPEDEF: |
| 1288 | type = check_typedef (type); |
| 1289 | goto retry; |
| 1290 | case TYPE_CODE_INT: |
| 1291 | case TYPE_CODE_CHAR: |
| 1292 | case TYPE_CODE_ENUM: |
| 1293 | case TYPE_CODE_BOOL: |
| 1294 | case TYPE_CODE_RANGE: |
| 1295 | store_signed_integer (VALUE_CONTENTS_RAW (val), len, num); |
| 1296 | break; |
| 1297 | |
| 1298 | case TYPE_CODE_REF: |
| 1299 | case TYPE_CODE_PTR: |
| 1300 | store_typed_address (VALUE_CONTENTS_RAW (val), type, (CORE_ADDR) num); |
| 1301 | break; |
| 1302 | |
| 1303 | default: |
| 1304 | error ("Unexpected type (%d) encountered for integer constant.", code); |
| 1305 | } |
| 1306 | return val; |
| 1307 | } |
| 1308 | |
| 1309 | |
| 1310 | /* Create a value representing a pointer of type TYPE to the address |
| 1311 | ADDR. */ |
| 1312 | value_ptr |
| 1313 | value_from_pointer (struct type *type, CORE_ADDR addr) |
| 1314 | { |
| 1315 | value_ptr val = allocate_value (type); |
| 1316 | store_typed_address (VALUE_CONTENTS_RAW (val), type, addr); |
| 1317 | return val; |
| 1318 | } |
| 1319 | |
| 1320 | |
| 1321 | /* Create a value for a string constant to be stored locally |
| 1322 | (not in the inferior's memory space, but in GDB memory). |
| 1323 | This is analogous to value_from_longest, which also does not |
| 1324 | use inferior memory. String shall NOT contain embedded nulls. */ |
| 1325 | |
| 1326 | value_ptr |
| 1327 | value_from_string (char *ptr) |
| 1328 | { |
| 1329 | value_ptr val; |
| 1330 | int len = strlen (ptr); |
| 1331 | int lowbound = current_language->string_lower_bound; |
| 1332 | struct type *rangetype = |
| 1333 | create_range_type ((struct type *) NULL, |
| 1334 | builtin_type_int, |
| 1335 | lowbound, len + lowbound - 1); |
| 1336 | struct type *stringtype = |
| 1337 | create_array_type ((struct type *) NULL, |
| 1338 | *current_language->string_char_type, |
| 1339 | rangetype); |
| 1340 | |
| 1341 | val = allocate_value (stringtype); |
| 1342 | memcpy (VALUE_CONTENTS_RAW (val), ptr, len); |
| 1343 | return val; |
| 1344 | } |
| 1345 | |
| 1346 | value_ptr |
| 1347 | value_from_double (struct type *type, DOUBLEST num) |
| 1348 | { |
| 1349 | register value_ptr val = allocate_value (type); |
| 1350 | struct type *base_type = check_typedef (type); |
| 1351 | register enum type_code code = TYPE_CODE (base_type); |
| 1352 | register int len = TYPE_LENGTH (base_type); |
| 1353 | |
| 1354 | if (code == TYPE_CODE_FLT) |
| 1355 | { |
| 1356 | store_typed_floating (VALUE_CONTENTS_RAW (val), base_type, num); |
| 1357 | } |
| 1358 | else |
| 1359 | error ("Unexpected type encountered for floating constant."); |
| 1360 | |
| 1361 | return val; |
| 1362 | } |
| 1363 | \f |
| 1364 | /* Deal with the value that is "about to be returned". */ |
| 1365 | |
| 1366 | /* Return the value that a function returning now |
| 1367 | would be returning to its caller, assuming its type is VALTYPE. |
| 1368 | RETBUF is where we look for what ought to be the contents |
| 1369 | of the registers (in raw form). This is because it is often |
| 1370 | desirable to restore old values to those registers |
| 1371 | after saving the contents of interest, and then call |
| 1372 | this function using the saved values. |
| 1373 | struct_return is non-zero when the function in question is |
| 1374 | using the structure return conventions on the machine in question; |
| 1375 | 0 when it is using the value returning conventions (this often |
| 1376 | means returning pointer to where structure is vs. returning value). */ |
| 1377 | |
| 1378 | /* ARGSUSED */ |
| 1379 | value_ptr |
| 1380 | value_being_returned (struct type *valtype, char *retbuf, int struct_return) |
| 1381 | { |
| 1382 | register value_ptr val; |
| 1383 | CORE_ADDR addr; |
| 1384 | |
| 1385 | /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */ |
| 1386 | if (EXTRACT_STRUCT_VALUE_ADDRESS_P ()) |
| 1387 | if (struct_return) |
| 1388 | { |
| 1389 | addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf); |
| 1390 | if (!addr) |
| 1391 | error ("Function return value unknown"); |
| 1392 | return value_at (valtype, addr, NULL); |
| 1393 | } |
| 1394 | |
| 1395 | val = allocate_value (valtype); |
| 1396 | CHECK_TYPEDEF (valtype); |
| 1397 | EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val)); |
| 1398 | |
| 1399 | return val; |
| 1400 | } |
| 1401 | |
| 1402 | /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of |
| 1403 | EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc |
| 1404 | and TYPE is the type (which is known to be struct, union or array). |
| 1405 | |
| 1406 | On most machines, the struct convention is used unless we are |
| 1407 | using gcc and the type is of a special size. */ |
| 1408 | /* As of about 31 Mar 93, GCC was changed to be compatible with the |
| 1409 | native compiler. GCC 2.3.3 was the last release that did it the |
| 1410 | old way. Since gcc2_compiled was not changed, we have no |
| 1411 | way to correctly win in all cases, so we just do the right thing |
| 1412 | for gcc1 and for gcc2 after this change. Thus it loses for gcc |
| 1413 | 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled |
| 1414 | would cause more chaos than dealing with some struct returns being |
| 1415 | handled wrong. */ |
| 1416 | |
| 1417 | int |
| 1418 | generic_use_struct_convention (int gcc_p, struct type *value_type) |
| 1419 | { |
| 1420 | return !((gcc_p == 1) |
| 1421 | && (TYPE_LENGTH (value_type) == 1 |
| 1422 | || TYPE_LENGTH (value_type) == 2 |
| 1423 | || TYPE_LENGTH (value_type) == 4 |
| 1424 | || TYPE_LENGTH (value_type) == 8)); |
| 1425 | } |
| 1426 | |
| 1427 | /* Return true if the function specified is using the structure returning |
| 1428 | convention on this machine to return arguments, or 0 if it is using |
| 1429 | the value returning convention. FUNCTION is the value representing |
| 1430 | the function, FUNCADDR is the address of the function, and VALUE_TYPE |
| 1431 | is the type returned by the function. GCC_P is nonzero if compiled |
| 1432 | with GCC. */ |
| 1433 | |
| 1434 | /* ARGSUSED */ |
| 1435 | int |
| 1436 | using_struct_return (value_ptr function, CORE_ADDR funcaddr, |
| 1437 | struct type *value_type, int gcc_p) |
| 1438 | { |
| 1439 | register enum type_code code = TYPE_CODE (value_type); |
| 1440 | |
| 1441 | if (code == TYPE_CODE_ERROR) |
| 1442 | error ("Function return type unknown."); |
| 1443 | |
| 1444 | if (code == TYPE_CODE_STRUCT |
| 1445 | || code == TYPE_CODE_UNION |
| 1446 | || code == TYPE_CODE_ARRAY |
| 1447 | || RETURN_VALUE_ON_STACK (value_type)) |
| 1448 | return USE_STRUCT_CONVENTION (gcc_p, value_type); |
| 1449 | |
| 1450 | return 0; |
| 1451 | } |
| 1452 | |
| 1453 | /* Store VAL so it will be returned if a function returns now. |
| 1454 | Does not verify that VAL's type matches what the current |
| 1455 | function wants to return. */ |
| 1456 | |
| 1457 | void |
| 1458 | set_return_value (value_ptr val) |
| 1459 | { |
| 1460 | struct type *type = check_typedef (VALUE_TYPE (val)); |
| 1461 | register enum type_code code = TYPE_CODE (type); |
| 1462 | |
| 1463 | if (code == TYPE_CODE_ERROR) |
| 1464 | error ("Function return type unknown."); |
| 1465 | |
| 1466 | if (code == TYPE_CODE_STRUCT |
| 1467 | || code == TYPE_CODE_UNION) /* FIXME, implement struct return. */ |
| 1468 | error ("GDB does not support specifying a struct or union return value."); |
| 1469 | |
| 1470 | STORE_RETURN_VALUE (type, VALUE_CONTENTS (val)); |
| 1471 | } |
| 1472 | \f |
| 1473 | void |
| 1474 | _initialize_values (void) |
| 1475 | { |
| 1476 | add_cmd ("convenience", no_class, show_convenience, |
| 1477 | "Debugger convenience (\"$foo\") variables.\n\ |
| 1478 | These variables are created when you assign them values;\n\ |
| 1479 | thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\ |
| 1480 | A few convenience variables are given values automatically:\n\ |
| 1481 | \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\ |
| 1482 | \"$__\" holds the contents of the last address examined with \"x\".", |
| 1483 | &showlist); |
| 1484 | |
| 1485 | add_cmd ("values", no_class, show_values, |
| 1486 | "Elements of value history around item number IDX (or last ten).", |
| 1487 | &showlist); |
| 1488 | } |