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1 /* Support for printing C values for GDB, the GNU debugger.
2
3 Copyright (C) 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
4 1998, 1999, 2000, 2001, 2003, 2005, 2006, 2007, 2008, 2009
5 Free Software Foundation, Inc.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #include "defs.h"
23 #include "gdb_string.h"
24 #include "symtab.h"
25 #include "gdbtypes.h"
26 #include "expression.h"
27 #include "value.h"
28 #include "valprint.h"
29 #include "language.h"
30 #include "c-lang.h"
31 #include "cp-abi.h"
32 #include "target.h"
33 \f
34
35 /* Print function pointer with inferior address ADDRESS onto stdio
36 stream STREAM. */
37
38 static void
39 print_function_pointer_address (struct gdbarch *gdbarch, CORE_ADDR address,
40 struct ui_file *stream, int addressprint)
41 {
42 CORE_ADDR func_addr = gdbarch_convert_from_func_ptr_addr (gdbarch, address,
43 &current_target);
44
45 /* If the function pointer is represented by a description, print the
46 address of the description. */
47 if (addressprint && func_addr != address)
48 {
49 fputs_filtered ("@", stream);
50 fputs_filtered (paddress (address), stream);
51 fputs_filtered (": ", stream);
52 }
53 print_address_demangle (func_addr, stream, demangle);
54 }
55
56
57 /* A helper for textual_element_type. This checks the name of the
58 typedef. This is bogus but it isn't apparent that the compiler
59 provides us the help we may need. */
60
61 static int
62 textual_name (const char *name)
63 {
64 return (!strcmp (name, "wchar_t")
65 || !strcmp (name, "char16_t")
66 || !strcmp (name, "char32_t"));
67 }
68
69 /* Apply a heuristic to decide whether an array of TYPE or a pointer
70 to TYPE should be printed as a textual string. Return non-zero if
71 it should, or zero if it should be treated as an array of integers
72 or pointer to integers. FORMAT is the current format letter,
73 or 0 if none.
74
75 We guess that "char" is a character. Explicitly signed and
76 unsigned character types are also characters. Integer data from
77 vector types is not. The user can override this by using the /s
78 format letter. */
79
80 static int
81 textual_element_type (struct type *type, char format)
82 {
83 struct type *true_type, *iter_type;
84
85 if (format != 0 && format != 's')
86 return 0;
87
88 /* We also rely on this for its side effect of setting up all the
89 typedef pointers. */
90 true_type = check_typedef (type);
91
92 /* TYPE_CODE_CHAR is always textual. */
93 if (TYPE_CODE (true_type) == TYPE_CODE_CHAR)
94 return 1;
95
96 /* Any other character-like types must be integral. */
97 if (TYPE_CODE (true_type) != TYPE_CODE_INT)
98 return 0;
99
100 /* We peel typedefs one by one, looking for a match. */
101 iter_type = type;
102 while (iter_type)
103 {
104 /* Check the name of the type. */
105 if (TYPE_NAME (iter_type) && textual_name (TYPE_NAME (iter_type)))
106 return 1;
107
108 if (TYPE_CODE (iter_type) != TYPE_CODE_TYPEDEF)
109 break;
110
111 /* Peel a single typedef. If the typedef doesn't have a target
112 type, we use check_typedef and hope the result is ok -- it
113 might be for C++, where wchar_t is a built-in type. */
114 if (TYPE_TARGET_TYPE (iter_type))
115 iter_type = TYPE_TARGET_TYPE (iter_type);
116 else
117 iter_type = check_typedef (iter_type);
118 }
119
120 if (format == 's')
121 {
122 /* Print this as a string if we can manage it. For now, no
123 wide character support. */
124 if (TYPE_CODE (true_type) == TYPE_CODE_INT
125 && TYPE_LENGTH (true_type) == 1)
126 return 1;
127 }
128 else
129 {
130 /* If a one-byte TYPE_CODE_INT is missing the not-a-character
131 flag, then we treat it as text; otherwise, we assume it's
132 being used as data. */
133 if (TYPE_CODE (true_type) == TYPE_CODE_INT
134 && TYPE_LENGTH (true_type) == 1
135 && !TYPE_NOTTEXT (true_type))
136 return 1;
137 }
138
139 return 0;
140 }
141
142
143 /* Print data of type TYPE located at VALADDR (within GDB), which came from
144 the inferior at address ADDRESS, onto stdio stream STREAM according to
145 OPTIONS. The data at VALADDR is in target byte order.
146
147 If the data are a string pointer, returns the number of string characters
148 printed. */
149
150 int
151 c_val_print (struct type *type, const gdb_byte *valaddr, int embedded_offset,
152 CORE_ADDR address, struct ui_file *stream, int recurse,
153 const struct value_print_options *options)
154 {
155 struct gdbarch *gdbarch = get_type_arch (type);
156 unsigned int i = 0; /* Number of characters printed */
157 unsigned len;
158 struct type *elttype, *unresolved_elttype;
159 struct type *unresolved_type = type;
160 unsigned eltlen;
161 LONGEST val;
162 CORE_ADDR addr;
163
164 CHECK_TYPEDEF (type);
165 switch (TYPE_CODE (type))
166 {
167 case TYPE_CODE_ARRAY:
168 unresolved_elttype = TYPE_TARGET_TYPE (type);
169 elttype = check_typedef (unresolved_elttype);
170 if (TYPE_LENGTH (type) > 0 && TYPE_LENGTH (unresolved_elttype) > 0)
171 {
172 eltlen = TYPE_LENGTH (elttype);
173 len = TYPE_LENGTH (type) / eltlen;
174 if (options->prettyprint_arrays)
175 {
176 print_spaces_filtered (2 + 2 * recurse, stream);
177 }
178
179 /* Print arrays of textual chars with a string syntax. */
180 if (textual_element_type (unresolved_elttype, options->format))
181 {
182 /* If requested, look for the first null char and only print
183 elements up to it. */
184 if (options->stop_print_at_null)
185 {
186 unsigned int temp_len;
187
188 for (temp_len = 0;
189 (temp_len < len
190 && temp_len < options->print_max
191 && extract_unsigned_integer (valaddr + embedded_offset
192 + temp_len * eltlen,
193 eltlen) == 0);
194 ++temp_len)
195 ;
196 len = temp_len;
197 }
198
199 LA_PRINT_STRING (stream, unresolved_elttype,
200 valaddr + embedded_offset, len, 0, options);
201 i = len;
202 }
203 else
204 {
205 fprintf_filtered (stream, "{");
206 /* If this is a virtual function table, print the 0th
207 entry specially, and the rest of the members normally. */
208 if (cp_is_vtbl_ptr_type (elttype))
209 {
210 i = 1;
211 fprintf_filtered (stream, _("%d vtable entries"), len - 1);
212 }
213 else
214 {
215 i = 0;
216 }
217 val_print_array_elements (type, valaddr + embedded_offset, address, stream,
218 recurse, options, i);
219 fprintf_filtered (stream, "}");
220 }
221 break;
222 }
223 /* Array of unspecified length: treat like pointer to first elt. */
224 addr = address;
225 goto print_unpacked_pointer;
226
227 case TYPE_CODE_MEMBERPTR:
228 if (options->format)
229 {
230 print_scalar_formatted (valaddr + embedded_offset, type,
231 options, 0, stream);
232 break;
233 }
234 cp_print_class_member (valaddr + embedded_offset, type, stream, "&");
235 break;
236
237 case TYPE_CODE_METHODPTR:
238 cplus_print_method_ptr (valaddr + embedded_offset, type, stream);
239 break;
240
241 case TYPE_CODE_PTR:
242 if (options->format && options->format != 's')
243 {
244 print_scalar_formatted (valaddr + embedded_offset, type,
245 options, 0, stream);
246 break;
247 }
248 if (options->vtblprint && cp_is_vtbl_ptr_type (type))
249 {
250 /* Print the unmangled name if desired. */
251 /* Print vtable entry - we only get here if we ARE using
252 -fvtable_thunks. (Otherwise, look under TYPE_CODE_STRUCT.) */
253 CORE_ADDR addr
254 = extract_typed_address (valaddr + embedded_offset, type);
255 print_function_pointer_address (gdbarch, addr, stream,
256 options->addressprint);
257 break;
258 }
259 unresolved_elttype = TYPE_TARGET_TYPE (type);
260 elttype = check_typedef (unresolved_elttype);
261 {
262 addr = unpack_pointer (type, valaddr + embedded_offset);
263 print_unpacked_pointer:
264
265 if (TYPE_CODE (elttype) == TYPE_CODE_FUNC)
266 {
267 /* Try to print what function it points to. */
268 print_function_pointer_address (gdbarch, addr, stream,
269 options->addressprint);
270 /* Return value is irrelevant except for string pointers. */
271 return (0);
272 }
273
274 if (options->addressprint)
275 fputs_filtered (paddress (addr), stream);
276
277 /* For a pointer to a textual type, also print the string
278 pointed to, unless pointer is null. */
279
280 if (textual_element_type (unresolved_elttype, options->format)
281 && addr != 0)
282 {
283 i = val_print_string (unresolved_elttype, addr, -1, stream,
284 options);
285 }
286 else if (cp_is_vtbl_member (type))
287 {
288 /* print vtbl's nicely */
289 CORE_ADDR vt_address = unpack_pointer (type, valaddr + embedded_offset);
290
291 struct minimal_symbol *msymbol =
292 lookup_minimal_symbol_by_pc (vt_address);
293 if ((msymbol != NULL) &&
294 (vt_address == SYMBOL_VALUE_ADDRESS (msymbol)))
295 {
296 fputs_filtered (" <", stream);
297 fputs_filtered (SYMBOL_PRINT_NAME (msymbol), stream);
298 fputs_filtered (">", stream);
299 }
300 if (vt_address && options->vtblprint)
301 {
302 struct value *vt_val;
303 struct symbol *wsym = (struct symbol *) NULL;
304 struct type *wtype;
305 struct block *block = (struct block *) NULL;
306 int is_this_fld;
307
308 if (msymbol != NULL)
309 wsym = lookup_symbol (SYMBOL_LINKAGE_NAME (msymbol), block,
310 VAR_DOMAIN, &is_this_fld);
311
312 if (wsym)
313 {
314 wtype = SYMBOL_TYPE (wsym);
315 }
316 else
317 {
318 wtype = unresolved_elttype;
319 }
320 vt_val = value_at (wtype, vt_address);
321 common_val_print (vt_val, stream, recurse + 1, options,
322 current_language);
323 if (options->pretty)
324 {
325 fprintf_filtered (stream, "\n");
326 print_spaces_filtered (2 + 2 * recurse, stream);
327 }
328 }
329 }
330
331 /* Return number of characters printed, including the terminating
332 '\0' if we reached the end. val_print_string takes care including
333 the terminating '\0' if necessary. */
334 return i;
335 }
336 break;
337
338 case TYPE_CODE_REF:
339 elttype = check_typedef (TYPE_TARGET_TYPE (type));
340 if (options->addressprint)
341 {
342 CORE_ADDR addr
343 = extract_typed_address (valaddr + embedded_offset, type);
344 fprintf_filtered (stream, "@");
345 fputs_filtered (paddress (addr), stream);
346 if (options->deref_ref)
347 fputs_filtered (": ", stream);
348 }
349 /* De-reference the reference. */
350 if (options->deref_ref)
351 {
352 if (TYPE_CODE (elttype) != TYPE_CODE_UNDEF)
353 {
354 struct value *deref_val =
355 value_at
356 (TYPE_TARGET_TYPE (type),
357 unpack_pointer (type, valaddr + embedded_offset));
358 common_val_print (deref_val, stream, recurse, options,
359 current_language);
360 }
361 else
362 fputs_filtered ("???", stream);
363 }
364 break;
365
366 case TYPE_CODE_UNION:
367 if (recurse && !options->unionprint)
368 {
369 fprintf_filtered (stream, "{...}");
370 break;
371 }
372 /* Fall through. */
373 case TYPE_CODE_STRUCT:
374 /*FIXME: Abstract this away */
375 if (options->vtblprint && cp_is_vtbl_ptr_type (type))
376 {
377 /* Print the unmangled name if desired. */
378 /* Print vtable entry - we only get here if NOT using
379 -fvtable_thunks. (Otherwise, look under TYPE_CODE_PTR.) */
380 int offset = (embedded_offset +
381 TYPE_FIELD_BITPOS (type, VTBL_FNADDR_OFFSET) / 8);
382 struct type *field_type = TYPE_FIELD_TYPE (type, VTBL_FNADDR_OFFSET);
383 CORE_ADDR addr
384 = extract_typed_address (valaddr + offset, field_type);
385
386 print_function_pointer_address (gdbarch, addr, stream,
387 options->addressprint);
388 }
389 else
390 cp_print_value_fields (type, type, valaddr, embedded_offset, address, stream,
391 recurse, options, NULL, 0);
392 break;
393
394 case TYPE_CODE_ENUM:
395 if (options->format)
396 {
397 print_scalar_formatted (valaddr + embedded_offset, type,
398 options, 0, stream);
399 break;
400 }
401 len = TYPE_NFIELDS (type);
402 val = unpack_long (type, valaddr + embedded_offset);
403 for (i = 0; i < len; i++)
404 {
405 QUIT;
406 if (val == TYPE_FIELD_BITPOS (type, i))
407 {
408 break;
409 }
410 }
411 if (i < len)
412 {
413 fputs_filtered (TYPE_FIELD_NAME (type, i), stream);
414 }
415 else
416 {
417 print_longest (stream, 'd', 0, val);
418 }
419 break;
420
421 case TYPE_CODE_FLAGS:
422 if (options->format)
423 print_scalar_formatted (valaddr + embedded_offset, type,
424 options, 0, stream);
425 else
426 val_print_type_code_flags (type, valaddr + embedded_offset, stream);
427 break;
428
429 case TYPE_CODE_FUNC:
430 case TYPE_CODE_METHOD:
431 if (options->format)
432 {
433 print_scalar_formatted (valaddr + embedded_offset, type,
434 options, 0, stream);
435 break;
436 }
437 /* FIXME, we should consider, at least for ANSI C language, eliminating
438 the distinction made between FUNCs and POINTERs to FUNCs. */
439 fprintf_filtered (stream, "{");
440 type_print (type, "", stream, -1);
441 fprintf_filtered (stream, "} ");
442 /* Try to print what function it points to, and its address. */
443 print_address_demangle (address, stream, demangle);
444 break;
445
446 case TYPE_CODE_BOOL:
447 if (options->format || options->output_format)
448 {
449 struct value_print_options opts = *options;
450 opts.format = (options->format ? options->format
451 : options->output_format);
452 print_scalar_formatted (valaddr + embedded_offset, type,
453 &opts, 0, stream);
454 }
455 else
456 {
457 val = unpack_long (type, valaddr + embedded_offset);
458 if (val == 0)
459 fputs_filtered ("false", stream);
460 else if (val == 1)
461 fputs_filtered ("true", stream);
462 else
463 print_longest (stream, 'd', 0, val);
464 }
465 break;
466
467 case TYPE_CODE_RANGE:
468 /* FIXME: create_range_type does not set the unsigned bit in a
469 range type (I think it probably should copy it from the target
470 type), so we won't print values which are too large to
471 fit in a signed integer correctly. */
472 /* FIXME: Doesn't handle ranges of enums correctly. (Can't just
473 print with the target type, though, because the size of our type
474 and the target type might differ). */
475 /* FALLTHROUGH */
476
477 case TYPE_CODE_INT:
478 if (options->format || options->output_format)
479 {
480 struct value_print_options opts = *options;
481 opts.format = (options->format ? options->format
482 : options->output_format);
483 print_scalar_formatted (valaddr + embedded_offset, type,
484 &opts, 0, stream);
485 }
486 else
487 {
488 val_print_type_code_int (type, valaddr + embedded_offset, stream);
489 /* C and C++ has no single byte int type, char is used instead.
490 Since we don't know whether the value is really intended to
491 be used as an integer or a character, print the character
492 equivalent as well. */
493 if (textual_element_type (unresolved_type, options->format))
494 {
495 fputs_filtered (" ", stream);
496 LA_PRINT_CHAR ((unsigned char) unpack_long (type, valaddr + embedded_offset),
497 unresolved_type, stream);
498 }
499 }
500 break;
501
502 case TYPE_CODE_CHAR:
503 if (options->format || options->output_format)
504 {
505 struct value_print_options opts = *options;
506 opts.format = (options->format ? options->format
507 : options->output_format);
508 print_scalar_formatted (valaddr + embedded_offset, type,
509 &opts, 0, stream);
510 }
511 else
512 {
513 val = unpack_long (type, valaddr + embedded_offset);
514 if (TYPE_UNSIGNED (type))
515 fprintf_filtered (stream, "%u", (unsigned int) val);
516 else
517 fprintf_filtered (stream, "%d", (int) val);
518 fputs_filtered (" ", stream);
519 LA_PRINT_CHAR ((unsigned char) val, unresolved_type, stream);
520 }
521 break;
522
523 case TYPE_CODE_FLT:
524 if (options->format)
525 {
526 print_scalar_formatted (valaddr + embedded_offset, type,
527 options, 0, stream);
528 }
529 else
530 {
531 print_floating (valaddr + embedded_offset, type, stream);
532 }
533 break;
534
535 case TYPE_CODE_DECFLOAT:
536 if (options->format)
537 print_scalar_formatted (valaddr + embedded_offset, type,
538 options, 0, stream);
539 else
540 print_decimal_floating (valaddr + embedded_offset, type, stream);
541 break;
542
543 case TYPE_CODE_VOID:
544 fprintf_filtered (stream, "void");
545 break;
546
547 case TYPE_CODE_ERROR:
548 fprintf_filtered (stream, _("<error type>"));
549 break;
550
551 case TYPE_CODE_UNDEF:
552 /* This happens (without TYPE_FLAG_STUB set) on systems which don't use
553 dbx xrefs (NO_DBX_XREFS in gcc) if a file has a "struct foo *bar"
554 and no complete type for struct foo in that file. */
555 fprintf_filtered (stream, _("<incomplete type>"));
556 break;
557
558 case TYPE_CODE_COMPLEX:
559 if (options->format)
560 print_scalar_formatted (valaddr + embedded_offset,
561 TYPE_TARGET_TYPE (type),
562 options, 0, stream);
563 else
564 print_floating (valaddr + embedded_offset, TYPE_TARGET_TYPE (type),
565 stream);
566 fprintf_filtered (stream, " + ");
567 if (options->format)
568 print_scalar_formatted (valaddr + embedded_offset
569 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
570 TYPE_TARGET_TYPE (type),
571 options, 0, stream);
572 else
573 print_floating (valaddr + embedded_offset
574 + TYPE_LENGTH (TYPE_TARGET_TYPE (type)),
575 TYPE_TARGET_TYPE (type),
576 stream);
577 fprintf_filtered (stream, " * I");
578 break;
579
580 default:
581 error (_("Invalid C/C++ type code %d in symbol table."), TYPE_CODE (type));
582 }
583 gdb_flush (stream);
584 return (0);
585 }
586 \f
587 int
588 c_value_print (struct value *val, struct ui_file *stream,
589 const struct value_print_options *options)
590 {
591 struct type *type, *real_type, *val_type;
592 int full, top, using_enc;
593 struct value_print_options opts = *options;
594
595 opts.deref_ref = 1;
596
597 /* If it is a pointer, indicate what it points to.
598
599 Print type also if it is a reference.
600
601 C++: if it is a member pointer, we will take care
602 of that when we print it. */
603
604 /* Preserve the original type before stripping typedefs. We prefer
605 to pass down the original type when possible, but for local
606 checks it is better to look past the typedefs. */
607 val_type = value_type (val);
608 type = check_typedef (val_type);
609
610 if (TYPE_CODE (type) == TYPE_CODE_PTR
611 || TYPE_CODE (type) == TYPE_CODE_REF)
612 {
613 /* Hack: remove (char *) for char strings. Their
614 type is indicated by the quoted string anyway.
615 (Don't use textual_element_type here; quoted strings
616 are always exactly (char *), (wchar_t *), or the like. */
617 if (TYPE_CODE (val_type) == TYPE_CODE_PTR
618 && TYPE_NAME (val_type) == NULL
619 && TYPE_NAME (TYPE_TARGET_TYPE (val_type)) != NULL
620 && (strcmp (TYPE_NAME (TYPE_TARGET_TYPE (val_type)), "char") == 0
621 || textual_name (TYPE_NAME (TYPE_TARGET_TYPE (val_type)))))
622 {
623 /* Print nothing */
624 }
625 else if (options->objectprint
626 && (TYPE_CODE (TYPE_TARGET_TYPE (type)) == TYPE_CODE_CLASS))
627 {
628
629 if (TYPE_CODE(type) == TYPE_CODE_REF)
630 {
631 /* Copy value, change to pointer, so we don't get an
632 * error about a non-pointer type in value_rtti_target_type
633 */
634 struct value *temparg;
635 temparg=value_copy(val);
636 deprecated_set_value_type (temparg, lookup_pointer_type (TYPE_TARGET_TYPE(type)));
637 val=temparg;
638 }
639 /* Pointer to class, check real type of object */
640 fprintf_filtered (stream, "(");
641 real_type = value_rtti_target_type (val, &full, &top, &using_enc);
642 if (real_type)
643 {
644 /* RTTI entry found */
645 if (TYPE_CODE (type) == TYPE_CODE_PTR)
646 {
647 /* create a pointer type pointing to the real type */
648 type = lookup_pointer_type (real_type);
649 }
650 else
651 {
652 /* create a reference type referencing the real type */
653 type = lookup_reference_type (real_type);
654 }
655 /* JYG: Need to adjust pointer value. */
656 /* NOTE: cagney/2005-01-02: THIS IS BOGUS. */
657 value_contents_writeable (val)[0] -= top;
658
659 /* Note: When we look up RTTI entries, we don't get any
660 information on const or volatile attributes */
661 }
662 type_print (type, "", stream, -1);
663 fprintf_filtered (stream, ") ");
664 val_type = type;
665 }
666 else
667 {
668 /* normal case */
669 fprintf_filtered (stream, "(");
670 type_print (value_type (val), "", stream, -1);
671 fprintf_filtered (stream, ") ");
672 }
673 }
674
675 if (!value_initialized (val))
676 fprintf_filtered (stream, " [uninitialized] ");
677
678 if (options->objectprint && (TYPE_CODE (type) == TYPE_CODE_CLASS))
679 {
680 /* Attempt to determine real type of object */
681 real_type = value_rtti_type (val, &full, &top, &using_enc);
682 if (real_type)
683 {
684 /* We have RTTI information, so use it */
685 val = value_full_object (val, real_type, full, top, using_enc);
686 fprintf_filtered (stream, "(%s%s) ",
687 TYPE_NAME (real_type),
688 full ? "" : _(" [incomplete object]"));
689 /* Print out object: enclosing type is same as real_type if full */
690 return val_print (value_enclosing_type (val),
691 value_contents_all (val), 0,
692 value_address (val), stream, 0,
693 &opts, current_language);
694 /* Note: When we look up RTTI entries, we don't get any information on
695 const or volatile attributes */
696 }
697 else if (type != check_typedef (value_enclosing_type (val)))
698 {
699 /* No RTTI information, so let's do our best */
700 fprintf_filtered (stream, "(%s ?) ",
701 TYPE_NAME (value_enclosing_type (val)));
702 return val_print (value_enclosing_type (val),
703 value_contents_all (val), 0,
704 value_address (val), stream, 0,
705 &opts, current_language);
706 }
707 /* Otherwise, we end up at the return outside this "if" */
708 }
709
710 return val_print (val_type, value_contents_all (val),
711 value_embedded_offset (val),
712 value_address (val),
713 stream, 0, &opts, current_language);
714 }