Commit | Line | Data |
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c906108c | 1 | /* Low level packing and unpacking of values for GDB, the GNU Debugger. |
1bac305b | 2 | |
f23631e4 | 3 | Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, |
1bac305b AC |
4 | 1995, 1996, 1997, 1998, 1999, 2000, 2002, 2003 Free Software |
5 | Foundation, Inc. | |
c906108c | 6 | |
c5aa993b | 7 | This file is part of GDB. |
c906108c | 8 | |
c5aa993b JM |
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. | |
c906108c | 13 | |
c5aa993b JM |
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. | |
c906108c | 18 | |
c5aa993b JM |
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. */ | |
c906108c SS |
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" | |
c906108c SS |
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" | |
d16aafd8 | 36 | #include "doublest.h" |
5ae326fa | 37 | #include "gdb_assert.h" |
36160dc4 | 38 | #include "regcache.h" |
fe898f56 | 39 | #include "block.h" |
c906108c SS |
40 | |
41 | /* Prototypes for exported functions. */ | |
42 | ||
a14ed312 | 43 | void _initialize_values (void); |
c906108c SS |
44 | |
45 | /* Prototypes for local functions. */ | |
46 | ||
a14ed312 | 47 | static void show_values (char *, int); |
c906108c | 48 | |
a14ed312 | 49 | static void show_convenience (char *, int); |
c906108c | 50 | |
c906108c SS |
51 | |
52 | /* The value-history records all the values printed | |
53 | by print commands during this session. Each chunk | |
54 | records 60 consecutive values. The first chunk on | |
55 | the chain records the most recent values. | |
56 | The total number of values is in value_history_count. */ | |
57 | ||
58 | #define VALUE_HISTORY_CHUNK 60 | |
59 | ||
60 | struct value_history_chunk | |
c5aa993b JM |
61 | { |
62 | struct value_history_chunk *next; | |
f23631e4 | 63 | struct value *values[VALUE_HISTORY_CHUNK]; |
c5aa993b | 64 | }; |
c906108c SS |
65 | |
66 | /* Chain of chunks now in use. */ | |
67 | ||
68 | static struct value_history_chunk *value_history_chain; | |
69 | ||
70 | static int value_history_count; /* Abs number of last entry stored */ | |
71 | \f | |
72 | /* List of all value objects currently allocated | |
73 | (except for those released by calls to release_value) | |
74 | This is so they can be freed after each command. */ | |
75 | ||
f23631e4 | 76 | static struct value *all_values; |
c906108c SS |
77 | |
78 | /* Allocate a value that has the correct length for type TYPE. */ | |
79 | ||
f23631e4 | 80 | struct value * |
fba45db2 | 81 | allocate_value (struct type *type) |
c906108c | 82 | { |
f23631e4 | 83 | struct value *val; |
c906108c SS |
84 | struct type *atype = check_typedef (type); |
85 | ||
86 | val = (struct value *) xmalloc (sizeof (struct value) + TYPE_LENGTH (atype)); | |
87 | VALUE_NEXT (val) = all_values; | |
88 | all_values = val; | |
89 | VALUE_TYPE (val) = type; | |
90 | VALUE_ENCLOSING_TYPE (val) = type; | |
91 | VALUE_LVAL (val) = not_lval; | |
92 | VALUE_ADDRESS (val) = 0; | |
1df6926e | 93 | VALUE_FRAME_ID (val) = null_frame_id; |
c906108c SS |
94 | VALUE_OFFSET (val) = 0; |
95 | VALUE_BITPOS (val) = 0; | |
96 | VALUE_BITSIZE (val) = 0; | |
97 | VALUE_REGNO (val) = -1; | |
98 | VALUE_LAZY (val) = 0; | |
99 | VALUE_OPTIMIZED_OUT (val) = 0; | |
100 | VALUE_BFD_SECTION (val) = NULL; | |
101 | VALUE_EMBEDDED_OFFSET (val) = 0; | |
102 | VALUE_POINTED_TO_OFFSET (val) = 0; | |
103 | val->modifiable = 1; | |
104 | return val; | |
105 | } | |
106 | ||
107 | /* Allocate a value that has the correct length | |
108 | for COUNT repetitions type TYPE. */ | |
109 | ||
f23631e4 | 110 | struct value * |
fba45db2 | 111 | allocate_repeat_value (struct type *type, int count) |
c906108c | 112 | { |
c5aa993b | 113 | int low_bound = current_language->string_lower_bound; /* ??? */ |
c906108c SS |
114 | /* FIXME-type-allocation: need a way to free this type when we are |
115 | done with it. */ | |
116 | struct type *range_type | |
c5aa993b JM |
117 | = create_range_type ((struct type *) NULL, builtin_type_int, |
118 | low_bound, count + low_bound - 1); | |
c906108c SS |
119 | /* FIXME-type-allocation: need a way to free this type when we are |
120 | done with it. */ | |
121 | return allocate_value (create_array_type ((struct type *) NULL, | |
122 | type, range_type)); | |
123 | } | |
124 | ||
125 | /* Return a mark in the value chain. All values allocated after the | |
126 | mark is obtained (except for those released) are subject to being freed | |
127 | if a subsequent value_free_to_mark is passed the mark. */ | |
f23631e4 | 128 | struct value * |
fba45db2 | 129 | value_mark (void) |
c906108c SS |
130 | { |
131 | return all_values; | |
132 | } | |
133 | ||
134 | /* Free all values allocated since MARK was obtained by value_mark | |
135 | (except for those released). */ | |
136 | void | |
f23631e4 | 137 | value_free_to_mark (struct value *mark) |
c906108c | 138 | { |
f23631e4 AC |
139 | struct value *val; |
140 | struct value *next; | |
c906108c SS |
141 | |
142 | for (val = all_values; val && val != mark; val = next) | |
143 | { | |
144 | next = VALUE_NEXT (val); | |
145 | value_free (val); | |
146 | } | |
147 | all_values = val; | |
148 | } | |
149 | ||
150 | /* Free all the values that have been allocated (except for those released). | |
151 | Called after each command, successful or not. */ | |
152 | ||
153 | void | |
fba45db2 | 154 | free_all_values (void) |
c906108c | 155 | { |
f23631e4 AC |
156 | struct value *val; |
157 | struct value *next; | |
c906108c SS |
158 | |
159 | for (val = all_values; val; val = next) | |
160 | { | |
161 | next = VALUE_NEXT (val); | |
162 | value_free (val); | |
163 | } | |
164 | ||
165 | all_values = 0; | |
166 | } | |
167 | ||
168 | /* Remove VAL from the chain all_values | |
169 | so it will not be freed automatically. */ | |
170 | ||
171 | void | |
f23631e4 | 172 | release_value (struct value *val) |
c906108c | 173 | { |
f23631e4 | 174 | struct value *v; |
c906108c SS |
175 | |
176 | if (all_values == val) | |
177 | { | |
178 | all_values = val->next; | |
179 | return; | |
180 | } | |
181 | ||
182 | for (v = all_values; v; v = v->next) | |
183 | { | |
184 | if (v->next == val) | |
185 | { | |
186 | v->next = val->next; | |
187 | break; | |
188 | } | |
189 | } | |
190 | } | |
191 | ||
192 | /* Release all values up to mark */ | |
f23631e4 AC |
193 | struct value * |
194 | value_release_to_mark (struct value *mark) | |
c906108c | 195 | { |
f23631e4 AC |
196 | struct value *val; |
197 | struct value *next; | |
c906108c SS |
198 | |
199 | for (val = next = all_values; next; next = VALUE_NEXT (next)) | |
200 | if (VALUE_NEXT (next) == mark) | |
201 | { | |
202 | all_values = VALUE_NEXT (next); | |
203 | VALUE_NEXT (next) = 0; | |
204 | return val; | |
205 | } | |
206 | all_values = 0; | |
207 | return val; | |
208 | } | |
209 | ||
210 | /* Return a copy of the value ARG. | |
211 | It contains the same contents, for same memory address, | |
212 | but it's a different block of storage. */ | |
213 | ||
f23631e4 AC |
214 | struct value * |
215 | value_copy (struct value *arg) | |
c906108c SS |
216 | { |
217 | register struct type *encl_type = VALUE_ENCLOSING_TYPE (arg); | |
f23631e4 | 218 | struct value *val = allocate_value (encl_type); |
c906108c SS |
219 | VALUE_TYPE (val) = VALUE_TYPE (arg); |
220 | VALUE_LVAL (val) = VALUE_LVAL (arg); | |
221 | VALUE_ADDRESS (val) = VALUE_ADDRESS (arg); | |
222 | VALUE_OFFSET (val) = VALUE_OFFSET (arg); | |
223 | VALUE_BITPOS (val) = VALUE_BITPOS (arg); | |
224 | VALUE_BITSIZE (val) = VALUE_BITSIZE (arg); | |
1df6926e | 225 | VALUE_FRAME_ID (val) = VALUE_FRAME_ID (arg); |
c906108c SS |
226 | VALUE_REGNO (val) = VALUE_REGNO (arg); |
227 | VALUE_LAZY (val) = VALUE_LAZY (arg); | |
228 | VALUE_OPTIMIZED_OUT (val) = VALUE_OPTIMIZED_OUT (arg); | |
229 | VALUE_EMBEDDED_OFFSET (val) = VALUE_EMBEDDED_OFFSET (arg); | |
230 | VALUE_POINTED_TO_OFFSET (val) = VALUE_POINTED_TO_OFFSET (arg); | |
231 | VALUE_BFD_SECTION (val) = VALUE_BFD_SECTION (arg); | |
232 | val->modifiable = arg->modifiable; | |
233 | if (!VALUE_LAZY (val)) | |
234 | { | |
235 | memcpy (VALUE_CONTENTS_ALL_RAW (val), VALUE_CONTENTS_ALL_RAW (arg), | |
236 | TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg))); | |
237 | ||
238 | } | |
239 | return val; | |
240 | } | |
241 | \f | |
242 | /* Access to the value history. */ | |
243 | ||
244 | /* Record a new value in the value history. | |
245 | Returns the absolute history index of the entry. | |
246 | Result of -1 indicates the value was not saved; otherwise it is the | |
247 | value history index of this new item. */ | |
248 | ||
249 | int | |
f23631e4 | 250 | record_latest_value (struct value *val) |
c906108c SS |
251 | { |
252 | int i; | |
253 | ||
254 | /* We don't want this value to have anything to do with the inferior anymore. | |
255 | In particular, "set $1 = 50" should not affect the variable from which | |
256 | the value was taken, and fast watchpoints should be able to assume that | |
257 | a value on the value history never changes. */ | |
258 | if (VALUE_LAZY (val)) | |
259 | value_fetch_lazy (val); | |
260 | /* We preserve VALUE_LVAL so that the user can find out where it was fetched | |
261 | from. This is a bit dubious, because then *&$1 does not just return $1 | |
262 | but the current contents of that location. c'est la vie... */ | |
263 | val->modifiable = 0; | |
264 | release_value (val); | |
265 | ||
266 | /* Here we treat value_history_count as origin-zero | |
267 | and applying to the value being stored now. */ | |
268 | ||
269 | i = value_history_count % VALUE_HISTORY_CHUNK; | |
270 | if (i == 0) | |
271 | { | |
f23631e4 | 272 | struct value_history_chunk *new |
c5aa993b JM |
273 | = (struct value_history_chunk *) |
274 | xmalloc (sizeof (struct value_history_chunk)); | |
c906108c SS |
275 | memset (new->values, 0, sizeof new->values); |
276 | new->next = value_history_chain; | |
277 | value_history_chain = new; | |
278 | } | |
279 | ||
280 | value_history_chain->values[i] = val; | |
281 | ||
282 | /* Now we regard value_history_count as origin-one | |
283 | and applying to the value just stored. */ | |
284 | ||
285 | return ++value_history_count; | |
286 | } | |
287 | ||
288 | /* Return a copy of the value in the history with sequence number NUM. */ | |
289 | ||
f23631e4 | 290 | struct value * |
fba45db2 | 291 | access_value_history (int num) |
c906108c | 292 | { |
f23631e4 | 293 | struct value_history_chunk *chunk; |
c906108c SS |
294 | register int i; |
295 | register int absnum = num; | |
296 | ||
297 | if (absnum <= 0) | |
298 | absnum += value_history_count; | |
299 | ||
300 | if (absnum <= 0) | |
301 | { | |
302 | if (num == 0) | |
303 | error ("The history is empty."); | |
304 | else if (num == 1) | |
305 | error ("There is only one value in the history."); | |
306 | else | |
307 | error ("History does not go back to $$%d.", -num); | |
308 | } | |
309 | if (absnum > value_history_count) | |
310 | error ("History has not yet reached $%d.", absnum); | |
311 | ||
312 | absnum--; | |
313 | ||
314 | /* Now absnum is always absolute and origin zero. */ | |
315 | ||
316 | chunk = value_history_chain; | |
317 | for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK - absnum / VALUE_HISTORY_CHUNK; | |
318 | i > 0; i--) | |
319 | chunk = chunk->next; | |
320 | ||
321 | return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]); | |
322 | } | |
323 | ||
324 | /* Clear the value history entirely. | |
325 | Must be done when new symbol tables are loaded, | |
326 | because the type pointers become invalid. */ | |
327 | ||
328 | void | |
fba45db2 | 329 | clear_value_history (void) |
c906108c | 330 | { |
f23631e4 | 331 | struct value_history_chunk *next; |
c906108c | 332 | register int i; |
f23631e4 | 333 | struct value *val; |
c906108c SS |
334 | |
335 | while (value_history_chain) | |
336 | { | |
337 | for (i = 0; i < VALUE_HISTORY_CHUNK; i++) | |
338 | if ((val = value_history_chain->values[i]) != NULL) | |
b8c9b27d | 339 | xfree (val); |
c906108c | 340 | next = value_history_chain->next; |
b8c9b27d | 341 | xfree (value_history_chain); |
c906108c SS |
342 | value_history_chain = next; |
343 | } | |
344 | value_history_count = 0; | |
345 | } | |
346 | ||
347 | static void | |
fba45db2 | 348 | show_values (char *num_exp, int from_tty) |
c906108c SS |
349 | { |
350 | register int i; | |
f23631e4 | 351 | struct value *val; |
c906108c SS |
352 | static int num = 1; |
353 | ||
354 | if (num_exp) | |
355 | { | |
c5aa993b JM |
356 | /* "info history +" should print from the stored position. |
357 | "info history <exp>" should print around value number <exp>. */ | |
c906108c | 358 | if (num_exp[0] != '+' || num_exp[1] != '\0') |
bb518678 | 359 | num = parse_and_eval_long (num_exp) - 5; |
c906108c SS |
360 | } |
361 | else | |
362 | { | |
363 | /* "info history" means print the last 10 values. */ | |
364 | num = value_history_count - 9; | |
365 | } | |
366 | ||
367 | if (num <= 0) | |
368 | num = 1; | |
369 | ||
370 | for (i = num; i < num + 10 && i <= value_history_count; i++) | |
371 | { | |
372 | val = access_value_history (i); | |
373 | printf_filtered ("$%d = ", i); | |
374 | value_print (val, gdb_stdout, 0, Val_pretty_default); | |
375 | printf_filtered ("\n"); | |
376 | } | |
377 | ||
378 | /* The next "info history +" should start after what we just printed. */ | |
379 | num += 10; | |
380 | ||
381 | /* Hitting just return after this command should do the same thing as | |
382 | "info history +". If num_exp is null, this is unnecessary, since | |
383 | "info history +" is not useful after "info history". */ | |
384 | if (from_tty && num_exp) | |
385 | { | |
386 | num_exp[0] = '+'; | |
387 | num_exp[1] = '\0'; | |
388 | } | |
389 | } | |
390 | \f | |
391 | /* Internal variables. These are variables within the debugger | |
392 | that hold values assigned by debugger commands. | |
393 | The user refers to them with a '$' prefix | |
394 | that does not appear in the variable names stored internally. */ | |
395 | ||
396 | static struct internalvar *internalvars; | |
397 | ||
398 | /* Look up an internal variable with name NAME. NAME should not | |
399 | normally include a dollar sign. | |
400 | ||
401 | If the specified internal variable does not exist, | |
402 | one is created, with a void value. */ | |
403 | ||
404 | struct internalvar * | |
fba45db2 | 405 | lookup_internalvar (char *name) |
c906108c SS |
406 | { |
407 | register struct internalvar *var; | |
408 | ||
409 | for (var = internalvars; var; var = var->next) | |
5cb316ef | 410 | if (strcmp (var->name, name) == 0) |
c906108c SS |
411 | return var; |
412 | ||
413 | var = (struct internalvar *) xmalloc (sizeof (struct internalvar)); | |
414 | var->name = concat (name, NULL); | |
415 | var->value = allocate_value (builtin_type_void); | |
416 | release_value (var->value); | |
417 | var->next = internalvars; | |
418 | internalvars = var; | |
419 | return var; | |
420 | } | |
421 | ||
f23631e4 | 422 | struct value * |
fba45db2 | 423 | value_of_internalvar (struct internalvar *var) |
c906108c | 424 | { |
f23631e4 | 425 | struct value *val; |
c906108c | 426 | |
c906108c SS |
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 | |
fba45db2 | 436 | set_internalvar_component (struct internalvar *var, int offset, int bitpos, |
f23631e4 | 437 | int bitsize, struct value *newval) |
c906108c SS |
438 | { |
439 | register char *addr = VALUE_CONTENTS (var->value) + offset; | |
440 | ||
c906108c SS |
441 | if (bitsize) |
442 | modify_field (addr, value_as_long (newval), | |
443 | bitpos, bitsize); | |
444 | else | |
445 | memcpy (addr, VALUE_CONTENTS (newval), TYPE_LENGTH (VALUE_TYPE (newval))); | |
446 | } | |
447 | ||
448 | void | |
f23631e4 | 449 | set_internalvar (struct internalvar *var, struct value *val) |
c906108c | 450 | { |
f23631e4 | 451 | struct value *newval; |
c906108c | 452 | |
c906108c SS |
453 | newval = value_copy (val); |
454 | newval->modifiable = 1; | |
455 | ||
456 | /* Force the value to be fetched from the target now, to avoid problems | |
457 | later when this internalvar is referenced and the target is gone or | |
458 | has changed. */ | |
459 | if (VALUE_LAZY (newval)) | |
460 | value_fetch_lazy (newval); | |
461 | ||
462 | /* Begin code which must not call error(). If var->value points to | |
463 | something free'd, an error() obviously leaves a dangling pointer. | |
464 | But we also get a danling pointer if var->value points to | |
465 | something in the value chain (i.e., before release_value is | |
466 | called), because after the error free_all_values will get called before | |
467 | long. */ | |
b8c9b27d | 468 | xfree (var->value); |
c906108c SS |
469 | var->value = newval; |
470 | release_value (newval); | |
471 | /* End code which must not call error(). */ | |
472 | } | |
473 | ||
474 | char * | |
fba45db2 | 475 | internalvar_name (struct internalvar *var) |
c906108c SS |
476 | { |
477 | return var->name; | |
478 | } | |
479 | ||
480 | /* Free all internalvars. Done when new symtabs are loaded, | |
481 | because that makes the values invalid. */ | |
482 | ||
483 | void | |
fba45db2 | 484 | clear_internalvars (void) |
c906108c SS |
485 | { |
486 | register struct internalvar *var; | |
487 | ||
488 | while (internalvars) | |
489 | { | |
490 | var = internalvars; | |
491 | internalvars = var->next; | |
b8c9b27d KB |
492 | xfree (var->name); |
493 | xfree (var->value); | |
494 | xfree (var); | |
c906108c SS |
495 | } |
496 | } | |
497 | ||
498 | static void | |
fba45db2 | 499 | show_convenience (char *ignore, int from_tty) |
c906108c SS |
500 | { |
501 | register struct internalvar *var; | |
502 | int varseen = 0; | |
503 | ||
504 | for (var = internalvars; var; var = var->next) | |
505 | { | |
c906108c SS |
506 | if (!varseen) |
507 | { | |
508 | varseen = 1; | |
509 | } | |
510 | printf_filtered ("$%s = ", var->name); | |
511 | value_print (var->value, gdb_stdout, 0, Val_pretty_default); | |
512 | printf_filtered ("\n"); | |
513 | } | |
514 | if (!varseen) | |
515 | printf_unfiltered ("No debugger convenience variables now defined.\n\ | |
516 | Convenience variables have names starting with \"$\";\n\ | |
517 | use \"set\" as in \"set $foo = 5\" to define them.\n"); | |
518 | } | |
519 | \f | |
520 | /* Extract a value as a C number (either long or double). | |
521 | Knows how to convert fixed values to double, or | |
522 | floating values to long. | |
523 | Does not deallocate the value. */ | |
524 | ||
525 | LONGEST | |
f23631e4 | 526 | value_as_long (struct value *val) |
c906108c SS |
527 | { |
528 | /* This coerces arrays and functions, which is necessary (e.g. | |
529 | in disassemble_command). It also dereferences references, which | |
530 | I suspect is the most logical thing to do. */ | |
531 | COERCE_ARRAY (val); | |
532 | return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); | |
533 | } | |
534 | ||
535 | DOUBLEST | |
f23631e4 | 536 | value_as_double (struct value *val) |
c906108c SS |
537 | { |
538 | DOUBLEST foo; | |
539 | int inv; | |
c5aa993b | 540 | |
c906108c SS |
541 | foo = unpack_double (VALUE_TYPE (val), VALUE_CONTENTS (val), &inv); |
542 | if (inv) | |
543 | error ("Invalid floating value found in program."); | |
544 | return foo; | |
545 | } | |
4478b372 JB |
546 | /* Extract a value as a C pointer. Does not deallocate the value. |
547 | Note that val's type may not actually be a pointer; value_as_long | |
548 | handles all the cases. */ | |
c906108c | 549 | CORE_ADDR |
f23631e4 | 550 | value_as_address (struct value *val) |
c906108c SS |
551 | { |
552 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure | |
553 | whether we want this to be true eventually. */ | |
554 | #if 0 | |
555 | /* ADDR_BITS_REMOVE is wrong if we are being called for a | |
556 | non-address (e.g. argument to "signal", "info break", etc.), or | |
557 | for pointers to char, in which the low bits *are* significant. */ | |
c5aa993b | 558 | return ADDR_BITS_REMOVE (value_as_long (val)); |
c906108c | 559 | #else |
f312f057 JB |
560 | |
561 | /* There are several targets (IA-64, PowerPC, and others) which | |
562 | don't represent pointers to functions as simply the address of | |
563 | the function's entry point. For example, on the IA-64, a | |
564 | function pointer points to a two-word descriptor, generated by | |
565 | the linker, which contains the function's entry point, and the | |
566 | value the IA-64 "global pointer" register should have --- to | |
567 | support position-independent code. The linker generates | |
568 | descriptors only for those functions whose addresses are taken. | |
569 | ||
570 | On such targets, it's difficult for GDB to convert an arbitrary | |
571 | function address into a function pointer; it has to either find | |
572 | an existing descriptor for that function, or call malloc and | |
573 | build its own. On some targets, it is impossible for GDB to | |
574 | build a descriptor at all: the descriptor must contain a jump | |
575 | instruction; data memory cannot be executed; and code memory | |
576 | cannot be modified. | |
577 | ||
578 | Upon entry to this function, if VAL is a value of type `function' | |
579 | (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then | |
580 | VALUE_ADDRESS (val) is the address of the function. This is what | |
581 | you'll get if you evaluate an expression like `main'. The call | |
582 | to COERCE_ARRAY below actually does all the usual unary | |
583 | conversions, which includes converting values of type `function' | |
584 | to `pointer to function'. This is the challenging conversion | |
585 | discussed above. Then, `unpack_long' will convert that pointer | |
586 | back into an address. | |
587 | ||
588 | So, suppose the user types `disassemble foo' on an architecture | |
589 | with a strange function pointer representation, on which GDB | |
590 | cannot build its own descriptors, and suppose further that `foo' | |
591 | has no linker-built descriptor. The address->pointer conversion | |
592 | will signal an error and prevent the command from running, even | |
593 | though the next step would have been to convert the pointer | |
594 | directly back into the same address. | |
595 | ||
596 | The following shortcut avoids this whole mess. If VAL is a | |
597 | function, just return its address directly. */ | |
598 | if (TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC | |
599 | || TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_METHOD) | |
600 | return VALUE_ADDRESS (val); | |
601 | ||
67b2adb2 | 602 | COERCE_ARRAY (val); |
fc0c74b1 AC |
603 | |
604 | /* Some architectures (e.g. Harvard), map instruction and data | |
605 | addresses onto a single large unified address space. For | |
606 | instance: An architecture may consider a large integer in the | |
607 | range 0x10000000 .. 0x1000ffff to already represent a data | |
608 | addresses (hence not need a pointer to address conversion) while | |
609 | a small integer would still need to be converted integer to | |
610 | pointer to address. Just assume such architectures handle all | |
611 | integer conversions in a single function. */ | |
612 | ||
613 | /* JimB writes: | |
614 | ||
615 | I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we | |
616 | must admonish GDB hackers to make sure its behavior matches the | |
617 | compiler's, whenever possible. | |
618 | ||
619 | In general, I think GDB should evaluate expressions the same way | |
620 | the compiler does. When the user copies an expression out of | |
621 | their source code and hands it to a `print' command, they should | |
622 | get the same value the compiler would have computed. Any | |
623 | deviation from this rule can cause major confusion and annoyance, | |
624 | and needs to be justified carefully. In other words, GDB doesn't | |
625 | really have the freedom to do these conversions in clever and | |
626 | useful ways. | |
627 | ||
628 | AndrewC pointed out that users aren't complaining about how GDB | |
629 | casts integers to pointers; they are complaining that they can't | |
630 | take an address from a disassembly listing and give it to `x/i'. | |
631 | This is certainly important. | |
632 | ||
633 | Adding an architecture method like INTEGER_TO_ADDRESS certainly | |
634 | makes it possible for GDB to "get it right" in all circumstances | |
635 | --- the target has complete control over how things get done, so | |
636 | people can Do The Right Thing for their target without breaking | |
637 | anyone else. The standard doesn't specify how integers get | |
638 | converted to pointers; usually, the ABI doesn't either, but | |
639 | ABI-specific code is a more reasonable place to handle it. */ | |
640 | ||
641 | if (TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_PTR | |
642 | && TYPE_CODE (VALUE_TYPE (val)) != TYPE_CODE_REF | |
643 | && INTEGER_TO_ADDRESS_P ()) | |
644 | return INTEGER_TO_ADDRESS (VALUE_TYPE (val), VALUE_CONTENTS (val)); | |
645 | ||
67b2adb2 | 646 | return unpack_long (VALUE_TYPE (val), VALUE_CONTENTS (val)); |
c906108c SS |
647 | #endif |
648 | } | |
649 | \f | |
650 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR | |
651 | as a long, or as a double, assuming the raw data is described | |
652 | by type TYPE. Knows how to convert different sizes of values | |
653 | and can convert between fixed and floating point. We don't assume | |
654 | any alignment for the raw data. Return value is in host byte order. | |
655 | ||
656 | If you want functions and arrays to be coerced to pointers, and | |
657 | references to be dereferenced, call value_as_long() instead. | |
658 | ||
659 | C++: It is assumed that the front-end has taken care of | |
660 | all matters concerning pointers to members. A pointer | |
661 | to member which reaches here is considered to be equivalent | |
662 | to an INT (or some size). After all, it is only an offset. */ | |
663 | ||
664 | LONGEST | |
66140c26 | 665 | unpack_long (struct type *type, const char *valaddr) |
c906108c SS |
666 | { |
667 | register enum type_code code = TYPE_CODE (type); | |
668 | register int len = TYPE_LENGTH (type); | |
669 | register int nosign = TYPE_UNSIGNED (type); | |
670 | ||
671 | if (current_language->la_language == language_scm | |
672 | && is_scmvalue_type (type)) | |
673 | return scm_unpack (type, valaddr, TYPE_CODE_INT); | |
674 | ||
675 | switch (code) | |
676 | { | |
677 | case TYPE_CODE_TYPEDEF: | |
678 | return unpack_long (check_typedef (type), valaddr); | |
679 | case TYPE_CODE_ENUM: | |
680 | case TYPE_CODE_BOOL: | |
681 | case TYPE_CODE_INT: | |
682 | case TYPE_CODE_CHAR: | |
683 | case TYPE_CODE_RANGE: | |
684 | if (nosign) | |
685 | return extract_unsigned_integer (valaddr, len); | |
686 | else | |
687 | return extract_signed_integer (valaddr, len); | |
688 | ||
689 | case TYPE_CODE_FLT: | |
96d2f608 | 690 | return extract_typed_floating (valaddr, type); |
c906108c SS |
691 | |
692 | case TYPE_CODE_PTR: | |
693 | case TYPE_CODE_REF: | |
694 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure | |
c5aa993b | 695 | whether we want this to be true eventually. */ |
4478b372 | 696 | return extract_typed_address (valaddr, type); |
c906108c SS |
697 | |
698 | case TYPE_CODE_MEMBER: | |
699 | error ("not implemented: member types in unpack_long"); | |
700 | ||
701 | default: | |
702 | error ("Value can't be converted to integer."); | |
703 | } | |
c5aa993b | 704 | return 0; /* Placate lint. */ |
c906108c SS |
705 | } |
706 | ||
707 | /* Return a double value from the specified type and address. | |
708 | INVP points to an int which is set to 0 for valid value, | |
709 | 1 for invalid value (bad float format). In either case, | |
710 | the returned double is OK to use. Argument is in target | |
711 | format, result is in host format. */ | |
712 | ||
713 | DOUBLEST | |
66140c26 | 714 | unpack_double (struct type *type, const char *valaddr, int *invp) |
c906108c SS |
715 | { |
716 | enum type_code code; | |
717 | int len; | |
718 | int nosign; | |
719 | ||
720 | *invp = 0; /* Assume valid. */ | |
721 | CHECK_TYPEDEF (type); | |
722 | code = TYPE_CODE (type); | |
723 | len = TYPE_LENGTH (type); | |
724 | nosign = TYPE_UNSIGNED (type); | |
725 | if (code == TYPE_CODE_FLT) | |
726 | { | |
75bc7ddf AC |
727 | /* NOTE: cagney/2002-02-19: There was a test here to see if the |
728 | floating-point value was valid (using the macro | |
729 | INVALID_FLOAT). That test/macro have been removed. | |
730 | ||
731 | It turns out that only the VAX defined this macro and then | |
732 | only in a non-portable way. Fixing the portability problem | |
733 | wouldn't help since the VAX floating-point code is also badly | |
734 | bit-rotten. The target needs to add definitions for the | |
735 | methods TARGET_FLOAT_FORMAT and TARGET_DOUBLE_FORMAT - these | |
736 | exactly describe the target floating-point format. The | |
737 | problem here is that the corresponding floatformat_vax_f and | |
738 | floatformat_vax_d values these methods should be set to are | |
739 | also not defined either. Oops! | |
740 | ||
741 | Hopefully someone will add both the missing floatformat | |
742 | definitions and floatformat_is_invalid() function. */ | |
96d2f608 | 743 | return extract_typed_floating (valaddr, type); |
c906108c SS |
744 | } |
745 | else if (nosign) | |
746 | { | |
747 | /* Unsigned -- be sure we compensate for signed LONGEST. */ | |
c906108c | 748 | return (ULONGEST) unpack_long (type, valaddr); |
c906108c SS |
749 | } |
750 | else | |
751 | { | |
752 | /* Signed -- we are OK with unpack_long. */ | |
753 | return unpack_long (type, valaddr); | |
754 | } | |
755 | } | |
756 | ||
757 | /* Unpack raw data (copied from debugee, target byte order) at VALADDR | |
758 | as a CORE_ADDR, assuming the raw data is described by type TYPE. | |
759 | We don't assume any alignment for the raw data. Return value is in | |
760 | host byte order. | |
761 | ||
762 | If you want functions and arrays to be coerced to pointers, and | |
1aa20aa8 | 763 | references to be dereferenced, call value_as_address() instead. |
c906108c SS |
764 | |
765 | C++: It is assumed that the front-end has taken care of | |
766 | all matters concerning pointers to members. A pointer | |
767 | to member which reaches here is considered to be equivalent | |
768 | to an INT (or some size). After all, it is only an offset. */ | |
769 | ||
770 | CORE_ADDR | |
66140c26 | 771 | unpack_pointer (struct type *type, const char *valaddr) |
c906108c SS |
772 | { |
773 | /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure | |
774 | whether we want this to be true eventually. */ | |
775 | return unpack_long (type, valaddr); | |
776 | } | |
4478b372 | 777 | |
c906108c | 778 | \f |
2c2738a0 DC |
779 | /* Get the value of the FIELDN'th field (which must be static) of |
780 | TYPE. Return NULL if the field doesn't exist or has been | |
781 | optimized out. */ | |
c906108c | 782 | |
f23631e4 | 783 | struct value * |
fba45db2 | 784 | value_static_field (struct type *type, int fieldno) |
c906108c | 785 | { |
948e66d9 DJ |
786 | struct value *retval; |
787 | ||
c906108c SS |
788 | if (TYPE_FIELD_STATIC_HAS_ADDR (type, fieldno)) |
789 | { | |
948e66d9 DJ |
790 | retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
791 | TYPE_FIELD_STATIC_PHYSADDR (type, fieldno), | |
792 | NULL); | |
c906108c SS |
793 | } |
794 | else | |
795 | { | |
796 | char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno); | |
176620f1 | 797 | struct symbol *sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0, NULL); |
948e66d9 | 798 | if (sym == NULL) |
c906108c SS |
799 | { |
800 | /* With some compilers, e.g. HP aCC, static data members are reported | |
c5aa993b JM |
801 | as non-debuggable symbols */ |
802 | struct minimal_symbol *msym = lookup_minimal_symbol (phys_name, NULL, NULL); | |
c906108c SS |
803 | if (!msym) |
804 | return NULL; | |
805 | else | |
c5aa993b | 806 | { |
948e66d9 DJ |
807 | retval = value_at (TYPE_FIELD_TYPE (type, fieldno), |
808 | SYMBOL_VALUE_ADDRESS (msym), | |
809 | SYMBOL_BFD_SECTION (msym)); | |
c906108c SS |
810 | } |
811 | } | |
812 | else | |
813 | { | |
948e66d9 DJ |
814 | /* SYM should never have a SYMBOL_CLASS which will require |
815 | read_var_value to use the FRAME parameter. */ | |
816 | if (symbol_read_needs_frame (sym)) | |
817 | warning ("static field's value depends on the current " | |
818 | "frame - bad debug info?"); | |
819 | retval = read_var_value (sym, NULL); | |
2b127877 | 820 | } |
948e66d9 DJ |
821 | if (retval && VALUE_LVAL (retval) == lval_memory) |
822 | SET_FIELD_PHYSADDR (TYPE_FIELD (type, fieldno), | |
823 | VALUE_ADDRESS (retval)); | |
c906108c | 824 | } |
948e66d9 | 825 | return retval; |
c906108c SS |
826 | } |
827 | ||
2b127877 DB |
828 | /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE. |
829 | You have to be careful here, since the size of the data area for the value | |
830 | is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger | |
831 | than the old enclosing type, you have to allocate more space for the data. | |
832 | The return value is a pointer to the new version of this value structure. */ | |
833 | ||
f23631e4 AC |
834 | struct value * |
835 | value_change_enclosing_type (struct value *val, struct type *new_encl_type) | |
2b127877 DB |
836 | { |
837 | if (TYPE_LENGTH (new_encl_type) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val))) | |
838 | { | |
839 | VALUE_ENCLOSING_TYPE (val) = new_encl_type; | |
840 | return val; | |
841 | } | |
842 | else | |
843 | { | |
f23631e4 AC |
844 | struct value *new_val; |
845 | struct value *prev; | |
2b127877 | 846 | |
f23631e4 | 847 | new_val = (struct value *) xrealloc (val, sizeof (struct value) + TYPE_LENGTH (new_encl_type)); |
cc303028 PM |
848 | |
849 | VALUE_ENCLOSING_TYPE (new_val) = new_encl_type; | |
850 | ||
2b127877 DB |
851 | /* We have to make sure this ends up in the same place in the value |
852 | chain as the original copy, so it's clean-up behavior is the same. | |
853 | If the value has been released, this is a waste of time, but there | |
854 | is no way to tell that in advance, so... */ | |
855 | ||
856 | if (val != all_values) | |
857 | { | |
858 | for (prev = all_values; prev != NULL; prev = prev->next) | |
859 | { | |
860 | if (prev->next == val) | |
861 | { | |
862 | prev->next = new_val; | |
863 | break; | |
864 | } | |
865 | } | |
866 | } | |
867 | ||
868 | return new_val; | |
869 | } | |
870 | } | |
871 | ||
c906108c SS |
872 | /* Given a value ARG1 (offset by OFFSET bytes) |
873 | of a struct or union type ARG_TYPE, | |
874 | extract and return the value of one of its (non-static) fields. | |
875 | FIELDNO says which field. */ | |
876 | ||
f23631e4 AC |
877 | struct value * |
878 | value_primitive_field (struct value *arg1, int offset, | |
fba45db2 | 879 | register int fieldno, register struct type *arg_type) |
c906108c | 880 | { |
f23631e4 | 881 | struct value *v; |
c906108c SS |
882 | register struct type *type; |
883 | ||
884 | CHECK_TYPEDEF (arg_type); | |
885 | type = TYPE_FIELD_TYPE (arg_type, fieldno); | |
886 | ||
887 | /* Handle packed fields */ | |
888 | ||
889 | if (TYPE_FIELD_BITSIZE (arg_type, fieldno)) | |
890 | { | |
891 | v = value_from_longest (type, | |
892 | unpack_field_as_long (arg_type, | |
893 | VALUE_CONTENTS (arg1) | |
c5aa993b | 894 | + offset, |
c906108c SS |
895 | fieldno)); |
896 | VALUE_BITPOS (v) = TYPE_FIELD_BITPOS (arg_type, fieldno) % 8; | |
897 | VALUE_BITSIZE (v) = TYPE_FIELD_BITSIZE (arg_type, fieldno); | |
2e70b7b9 MS |
898 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
899 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; | |
c906108c SS |
900 | } |
901 | else if (fieldno < TYPE_N_BASECLASSES (arg_type)) | |
902 | { | |
903 | /* This field is actually a base subobject, so preserve the | |
904 | entire object's contents for later references to virtual | |
905 | bases, etc. */ | |
906 | v = allocate_value (VALUE_ENCLOSING_TYPE (arg1)); | |
8d65888a | 907 | VALUE_TYPE (v) = type; |
c906108c SS |
908 | if (VALUE_LAZY (arg1)) |
909 | VALUE_LAZY (v) = 1; | |
910 | else | |
911 | memcpy (VALUE_CONTENTS_ALL_RAW (v), VALUE_CONTENTS_ALL_RAW (arg1), | |
912 | TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1))); | |
913 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1); | |
914 | VALUE_EMBEDDED_OFFSET (v) | |
c5aa993b JM |
915 | = offset + |
916 | VALUE_EMBEDDED_OFFSET (arg1) + | |
917 | TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; | |
c906108c SS |
918 | } |
919 | else | |
920 | { | |
921 | /* Plain old data member */ | |
922 | offset += TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; | |
923 | v = allocate_value (type); | |
924 | if (VALUE_LAZY (arg1)) | |
925 | VALUE_LAZY (v) = 1; | |
926 | else | |
927 | memcpy (VALUE_CONTENTS_RAW (v), | |
928 | VALUE_CONTENTS_RAW (arg1) + offset, | |
929 | TYPE_LENGTH (type)); | |
21cfb3b6 DJ |
930 | VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
931 | + VALUE_EMBEDDED_OFFSET (arg1); | |
c906108c SS |
932 | } |
933 | VALUE_LVAL (v) = VALUE_LVAL (arg1); | |
934 | if (VALUE_LVAL (arg1) == lval_internalvar) | |
935 | VALUE_LVAL (v) = lval_internalvar_component; | |
936 | VALUE_ADDRESS (v) = VALUE_ADDRESS (arg1); | |
a88c1392 | 937 | VALUE_REGNO (v) = VALUE_REGNO (arg1); |
c906108c | 938 | /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset |
c5aa993b | 939 | + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */ |
c906108c SS |
940 | return v; |
941 | } | |
942 | ||
943 | /* Given a value ARG1 of a struct or union type, | |
944 | extract and return the value of one of its (non-static) fields. | |
945 | FIELDNO says which field. */ | |
946 | ||
f23631e4 AC |
947 | struct value * |
948 | value_field (struct value *arg1, register int fieldno) | |
c906108c SS |
949 | { |
950 | return value_primitive_field (arg1, 0, fieldno, VALUE_TYPE (arg1)); | |
951 | } | |
952 | ||
953 | /* Return a non-virtual function as a value. | |
954 | F is the list of member functions which contains the desired method. | |
0478d61c FF |
955 | J is an index into F which provides the desired method. |
956 | ||
957 | We only use the symbol for its address, so be happy with either a | |
958 | full symbol or a minimal symbol. | |
959 | */ | |
c906108c | 960 | |
f23631e4 AC |
961 | struct value * |
962 | value_fn_field (struct value **arg1p, struct fn_field *f, int j, struct type *type, | |
fba45db2 | 963 | int offset) |
c906108c | 964 | { |
f23631e4 | 965 | struct value *v; |
c906108c | 966 | register struct type *ftype = TYPE_FN_FIELD_TYPE (f, j); |
0478d61c | 967 | char *physname = TYPE_FN_FIELD_PHYSNAME (f, j); |
c906108c | 968 | struct symbol *sym; |
0478d61c | 969 | struct minimal_symbol *msym; |
c906108c | 970 | |
176620f1 | 971 | sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0, NULL); |
5ae326fa | 972 | if (sym != NULL) |
0478d61c | 973 | { |
5ae326fa AC |
974 | msym = NULL; |
975 | } | |
976 | else | |
977 | { | |
978 | gdb_assert (sym == NULL); | |
0478d61c | 979 | msym = lookup_minimal_symbol (physname, NULL, NULL); |
5ae326fa AC |
980 | if (msym == NULL) |
981 | return NULL; | |
0478d61c FF |
982 | } |
983 | ||
c906108c | 984 | v = allocate_value (ftype); |
0478d61c FF |
985 | if (sym) |
986 | { | |
987 | VALUE_ADDRESS (v) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym)); | |
988 | } | |
989 | else | |
990 | { | |
991 | VALUE_ADDRESS (v) = SYMBOL_VALUE_ADDRESS (msym); | |
992 | } | |
c906108c SS |
993 | |
994 | if (arg1p) | |
c5aa993b JM |
995 | { |
996 | if (type != VALUE_TYPE (*arg1p)) | |
997 | *arg1p = value_ind (value_cast (lookup_pointer_type (type), | |
998 | value_addr (*arg1p))); | |
999 | ||
070ad9f0 | 1000 | /* Move the `this' pointer according to the offset. |
c5aa993b JM |
1001 | VALUE_OFFSET (*arg1p) += offset; |
1002 | */ | |
c906108c SS |
1003 | } |
1004 | ||
1005 | return v; | |
1006 | } | |
1007 | ||
c906108c SS |
1008 | \f |
1009 | /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at | |
1010 | VALADDR. | |
1011 | ||
1012 | Extracting bits depends on endianness of the machine. Compute the | |
1013 | number of least significant bits to discard. For big endian machines, | |
1014 | we compute the total number of bits in the anonymous object, subtract | |
1015 | off the bit count from the MSB of the object to the MSB of the | |
1016 | bitfield, then the size of the bitfield, which leaves the LSB discard | |
1017 | count. For little endian machines, the discard count is simply the | |
1018 | number of bits from the LSB of the anonymous object to the LSB of the | |
1019 | bitfield. | |
1020 | ||
1021 | If the field is signed, we also do sign extension. */ | |
1022 | ||
1023 | LONGEST | |
66140c26 | 1024 | unpack_field_as_long (struct type *type, const char *valaddr, int fieldno) |
c906108c SS |
1025 | { |
1026 | ULONGEST val; | |
1027 | ULONGEST valmask; | |
1028 | int bitpos = TYPE_FIELD_BITPOS (type, fieldno); | |
1029 | int bitsize = TYPE_FIELD_BITSIZE (type, fieldno); | |
1030 | int lsbcount; | |
1031 | struct type *field_type; | |
1032 | ||
1033 | val = extract_unsigned_integer (valaddr + bitpos / 8, sizeof (val)); | |
1034 | field_type = TYPE_FIELD_TYPE (type, fieldno); | |
1035 | CHECK_TYPEDEF (field_type); | |
1036 | ||
1037 | /* Extract bits. See comment above. */ | |
1038 | ||
1039 | if (BITS_BIG_ENDIAN) | |
1040 | lsbcount = (sizeof val * 8 - bitpos % 8 - bitsize); | |
1041 | else | |
1042 | lsbcount = (bitpos % 8); | |
1043 | val >>= lsbcount; | |
1044 | ||
1045 | /* If the field does not entirely fill a LONGEST, then zero the sign bits. | |
1046 | If the field is signed, and is negative, then sign extend. */ | |
1047 | ||
1048 | if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val))) | |
1049 | { | |
1050 | valmask = (((ULONGEST) 1) << bitsize) - 1; | |
1051 | val &= valmask; | |
1052 | if (!TYPE_UNSIGNED (field_type)) | |
1053 | { | |
1054 | if (val & (valmask ^ (valmask >> 1))) | |
1055 | { | |
1056 | val |= ~valmask; | |
1057 | } | |
1058 | } | |
1059 | } | |
1060 | return (val); | |
1061 | } | |
1062 | ||
1063 | /* Modify the value of a bitfield. ADDR points to a block of memory in | |
1064 | target byte order; the bitfield starts in the byte pointed to. FIELDVAL | |
1065 | is the desired value of the field, in host byte order. BITPOS and BITSIZE | |
1066 | indicate which bits (in target bit order) comprise the bitfield. */ | |
1067 | ||
1068 | void | |
fba45db2 | 1069 | modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize) |
c906108c SS |
1070 | { |
1071 | LONGEST oword; | |
1072 | ||
1073 | /* If a negative fieldval fits in the field in question, chop | |
1074 | off the sign extension bits. */ | |
1075 | if (bitsize < (8 * (int) sizeof (fieldval)) | |
1076 | && (~fieldval & ~((1 << (bitsize - 1)) - 1)) == 0) | |
1077 | fieldval = fieldval & ((1 << bitsize) - 1); | |
1078 | ||
1079 | /* Warn if value is too big to fit in the field in question. */ | |
1080 | if (bitsize < (8 * (int) sizeof (fieldval)) | |
c5aa993b | 1081 | && 0 != (fieldval & ~((1 << bitsize) - 1))) |
c906108c SS |
1082 | { |
1083 | /* FIXME: would like to include fieldval in the message, but | |
c5aa993b | 1084 | we don't have a sprintf_longest. */ |
c906108c SS |
1085 | warning ("Value does not fit in %d bits.", bitsize); |
1086 | ||
1087 | /* Truncate it, otherwise adjoining fields may be corrupted. */ | |
1088 | fieldval = fieldval & ((1 << bitsize) - 1); | |
1089 | } | |
1090 | ||
1091 | oword = extract_signed_integer (addr, sizeof oword); | |
1092 | ||
1093 | /* Shifting for bit field depends on endianness of the target machine. */ | |
1094 | if (BITS_BIG_ENDIAN) | |
1095 | bitpos = sizeof (oword) * 8 - bitpos - bitsize; | |
1096 | ||
1097 | /* Mask out old value, while avoiding shifts >= size of oword */ | |
1098 | if (bitsize < 8 * (int) sizeof (oword)) | |
c5aa993b | 1099 | oword &= ~(((((ULONGEST) 1) << bitsize) - 1) << bitpos); |
c906108c | 1100 | else |
c5aa993b | 1101 | oword &= ~((~(ULONGEST) 0) << bitpos); |
c906108c SS |
1102 | oword |= fieldval << bitpos; |
1103 | ||
1104 | store_signed_integer (addr, sizeof oword, oword); | |
1105 | } | |
1106 | \f | |
1107 | /* Convert C numbers into newly allocated values */ | |
1108 | ||
f23631e4 | 1109 | struct value * |
fba45db2 | 1110 | value_from_longest (struct type *type, register LONGEST num) |
c906108c | 1111 | { |
f23631e4 | 1112 | struct value *val = allocate_value (type); |
c906108c SS |
1113 | register enum type_code code; |
1114 | register int len; | |
c5aa993b | 1115 | retry: |
c906108c SS |
1116 | code = TYPE_CODE (type); |
1117 | len = TYPE_LENGTH (type); | |
1118 | ||
1119 | switch (code) | |
1120 | { | |
1121 | case TYPE_CODE_TYPEDEF: | |
1122 | type = check_typedef (type); | |
1123 | goto retry; | |
1124 | case TYPE_CODE_INT: | |
1125 | case TYPE_CODE_CHAR: | |
1126 | case TYPE_CODE_ENUM: | |
1127 | case TYPE_CODE_BOOL: | |
1128 | case TYPE_CODE_RANGE: | |
1129 | store_signed_integer (VALUE_CONTENTS_RAW (val), len, num); | |
1130 | break; | |
c5aa993b | 1131 | |
c906108c SS |
1132 | case TYPE_CODE_REF: |
1133 | case TYPE_CODE_PTR: | |
4478b372 | 1134 | store_typed_address (VALUE_CONTENTS_RAW (val), type, (CORE_ADDR) num); |
c906108c | 1135 | break; |
c5aa993b | 1136 | |
c906108c SS |
1137 | default: |
1138 | error ("Unexpected type (%d) encountered for integer constant.", code); | |
1139 | } | |
1140 | return val; | |
1141 | } | |
1142 | ||
4478b372 JB |
1143 | |
1144 | /* Create a value representing a pointer of type TYPE to the address | |
1145 | ADDR. */ | |
f23631e4 | 1146 | struct value * |
4478b372 JB |
1147 | value_from_pointer (struct type *type, CORE_ADDR addr) |
1148 | { | |
f23631e4 | 1149 | struct value *val = allocate_value (type); |
4478b372 JB |
1150 | store_typed_address (VALUE_CONTENTS_RAW (val), type, addr); |
1151 | return val; | |
1152 | } | |
1153 | ||
1154 | ||
0f71a2f6 | 1155 | /* Create a value for a string constant to be stored locally |
070ad9f0 | 1156 | (not in the inferior's memory space, but in GDB memory). |
0f71a2f6 JM |
1157 | This is analogous to value_from_longest, which also does not |
1158 | use inferior memory. String shall NOT contain embedded nulls. */ | |
1159 | ||
f23631e4 | 1160 | struct value * |
fba45db2 | 1161 | value_from_string (char *ptr) |
0f71a2f6 | 1162 | { |
f23631e4 | 1163 | struct value *val; |
c5aa993b | 1164 | int len = strlen (ptr); |
0f71a2f6 | 1165 | int lowbound = current_language->string_lower_bound; |
c5aa993b JM |
1166 | struct type *rangetype = |
1167 | create_range_type ((struct type *) NULL, | |
1168 | builtin_type_int, | |
1169 | lowbound, len + lowbound - 1); | |
1170 | struct type *stringtype = | |
1171 | create_array_type ((struct type *) NULL, | |
1172 | *current_language->string_char_type, | |
1173 | rangetype); | |
0f71a2f6 JM |
1174 | |
1175 | val = allocate_value (stringtype); | |
1176 | memcpy (VALUE_CONTENTS_RAW (val), ptr, len); | |
1177 | return val; | |
1178 | } | |
1179 | ||
f23631e4 | 1180 | struct value * |
fba45db2 | 1181 | value_from_double (struct type *type, DOUBLEST num) |
c906108c | 1182 | { |
f23631e4 | 1183 | struct value *val = allocate_value (type); |
c906108c SS |
1184 | struct type *base_type = check_typedef (type); |
1185 | register enum type_code code = TYPE_CODE (base_type); | |
1186 | register int len = TYPE_LENGTH (base_type); | |
1187 | ||
1188 | if (code == TYPE_CODE_FLT) | |
1189 | { | |
96d2f608 | 1190 | store_typed_floating (VALUE_CONTENTS_RAW (val), base_type, num); |
c906108c SS |
1191 | } |
1192 | else | |
1193 | error ("Unexpected type encountered for floating constant."); | |
1194 | ||
1195 | return val; | |
1196 | } | |
1197 | \f | |
1198 | /* Deal with the value that is "about to be returned". */ | |
1199 | ||
1200 | /* Return the value that a function returning now | |
1201 | would be returning to its caller, assuming its type is VALTYPE. | |
1202 | RETBUF is where we look for what ought to be the contents | |
1203 | of the registers (in raw form). This is because it is often | |
1204 | desirable to restore old values to those registers | |
1205 | after saving the contents of interest, and then call | |
1206 | this function using the saved values. | |
1207 | struct_return is non-zero when the function in question is | |
1208 | using the structure return conventions on the machine in question; | |
1209 | 0 when it is using the value returning conventions (this often | |
1210 | means returning pointer to where structure is vs. returning value). */ | |
1211 | ||
1669605f | 1212 | /* ARGSUSED */ |
f23631e4 | 1213 | struct value * |
049ee0e4 | 1214 | value_being_returned (struct type *valtype, struct regcache *retbuf, |
c48a845b | 1215 | int struct_return, CORE_ADDR struct_addr) |
c906108c | 1216 | { |
f23631e4 | 1217 | struct value *val; |
c906108c SS |
1218 | CORE_ADDR addr; |
1219 | ||
c48a845b MS |
1220 | if (struct_return) |
1221 | { | |
1222 | if (struct_addr != 0) | |
1223 | { | |
1224 | /* Struct return addr supplied by hand_function_call. */ | |
1225 | return value_at (valtype, struct_addr, NULL); | |
1226 | } | |
1227 | /* If one of these is not defined, just use EXTRACT_RETURN_VALUE | |
1228 | instead. */ | |
1229 | else if (EXTRACT_STRUCT_VALUE_ADDRESS_P ()) | |
1230 | { | |
1231 | addr = EXTRACT_STRUCT_VALUE_ADDRESS (retbuf); | |
1232 | if (!addr) | |
1233 | error ("Function return value unknown."); | |
1234 | return value_at (valtype, addr, NULL); | |
1235 | } | |
1236 | else if (DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS_P ()) | |
1237 | { | |
1238 | char *buf = deprecated_grub_regcache_for_registers (retbuf); | |
1239 | addr = DEPRECATED_EXTRACT_STRUCT_VALUE_ADDRESS (buf); | |
1240 | if (!addr) | |
1241 | error ("Function return value unknown."); | |
1242 | return value_at (valtype, addr, NULL); | |
1243 | } | |
1244 | } | |
c906108c SS |
1245 | |
1246 | val = allocate_value (valtype); | |
1247 | CHECK_TYPEDEF (valtype); | |
514621a9 EZ |
1248 | /* If the function returns void, don't bother fetching the return value. */ |
1249 | if (TYPE_CODE (valtype) != TYPE_CODE_VOID) | |
1250 | EXTRACT_RETURN_VALUE (valtype, retbuf, VALUE_CONTENTS_RAW (val)); | |
c906108c SS |
1251 | |
1252 | return val; | |
1253 | } | |
1254 | ||
1255 | /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of | |
1256 | EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc | |
1257 | and TYPE is the type (which is known to be struct, union or array). | |
1258 | ||
1259 | On most machines, the struct convention is used unless we are | |
1260 | using gcc and the type is of a special size. */ | |
1261 | /* As of about 31 Mar 93, GCC was changed to be compatible with the | |
1262 | native compiler. GCC 2.3.3 was the last release that did it the | |
1263 | old way. Since gcc2_compiled was not changed, we have no | |
1264 | way to correctly win in all cases, so we just do the right thing | |
1265 | for gcc1 and for gcc2 after this change. Thus it loses for gcc | |
1266 | 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled | |
1267 | would cause more chaos than dealing with some struct returns being | |
1268 | handled wrong. */ | |
1269 | ||
1270 | int | |
fba45db2 | 1271 | generic_use_struct_convention (int gcc_p, struct type *value_type) |
c5aa993b | 1272 | { |
c906108c | 1273 | return !((gcc_p == 1) |
c5aa993b JM |
1274 | && (TYPE_LENGTH (value_type) == 1 |
1275 | || TYPE_LENGTH (value_type) == 2 | |
1276 | || TYPE_LENGTH (value_type) == 4 | |
1277 | || TYPE_LENGTH (value_type) == 8)); | |
c906108c SS |
1278 | } |
1279 | ||
c906108c SS |
1280 | /* Return true if the function specified is using the structure returning |
1281 | convention on this machine to return arguments, or 0 if it is using | |
1282 | the value returning convention. FUNCTION is the value representing | |
1283 | the function, FUNCADDR is the address of the function, and VALUE_TYPE | |
1284 | is the type returned by the function. GCC_P is nonzero if compiled | |
1285 | with GCC. */ | |
1286 | ||
1669605f | 1287 | /* ARGSUSED */ |
c906108c | 1288 | int |
f23631e4 | 1289 | using_struct_return (struct value *function, CORE_ADDR funcaddr, |
1669605f | 1290 | struct type *value_type, int gcc_p) |
c906108c SS |
1291 | { |
1292 | register enum type_code code = TYPE_CODE (value_type); | |
1293 | ||
1294 | if (code == TYPE_CODE_ERROR) | |
1295 | error ("Function return type unknown."); | |
1296 | ||
1297 | if (code == TYPE_CODE_STRUCT | |
1298 | || code == TYPE_CODE_UNION | |
1299 | || code == TYPE_CODE_ARRAY | |
1300 | || RETURN_VALUE_ON_STACK (value_type)) | |
1301 | return USE_STRUCT_CONVENTION (gcc_p, value_type); | |
1302 | ||
1303 | return 0; | |
1304 | } | |
1305 | ||
1306 | /* Store VAL so it will be returned if a function returns now. | |
1307 | Does not verify that VAL's type matches what the current | |
1308 | function wants to return. */ | |
1309 | ||
1310 | void | |
f23631e4 | 1311 | set_return_value (struct value *val) |
c906108c SS |
1312 | { |
1313 | struct type *type = check_typedef (VALUE_TYPE (val)); | |
1314 | register enum type_code code = TYPE_CODE (type); | |
1315 | ||
1316 | if (code == TYPE_CODE_ERROR) | |
1317 | error ("Function return type unknown."); | |
1318 | ||
c5aa993b | 1319 | if (code == TYPE_CODE_STRUCT |
c906108c SS |
1320 | || code == TYPE_CODE_UNION) /* FIXME, implement struct return. */ |
1321 | error ("GDB does not support specifying a struct or union return value."); | |
1322 | ||
ebba8386 | 1323 | STORE_RETURN_VALUE (type, current_regcache, VALUE_CONTENTS (val)); |
c906108c SS |
1324 | } |
1325 | \f | |
1326 | void | |
fba45db2 | 1327 | _initialize_values (void) |
c906108c SS |
1328 | { |
1329 | add_cmd ("convenience", no_class, show_convenience, | |
c5aa993b | 1330 | "Debugger convenience (\"$foo\") variables.\n\ |
c906108c SS |
1331 | These variables are created when you assign them values;\n\ |
1332 | thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\ | |
1333 | A few convenience variables are given values automatically:\n\ | |
1334 | \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\ | |
1335 | \"$__\" holds the contents of the last address examined with \"x\".", | |
1336 | &showlist); | |
1337 | ||
1338 | add_cmd ("values", no_class, show_values, | |
1339 | "Elements of value history around item number IDX (or last ten).", | |
1340 | &showlist); | |
1341 | } |