1 /* Support for printing C++ values for GDB, the GNU debugger.
3 Copyright (C) 1986, 1988-1989, 1991-1997, 2000-2003, 2005-2012 Free
4 Software Foundation, Inc.
6 This file is part of GDB.
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 3 of the License, or
11 (at your option) any later version.
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.
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
22 #include "gdb_obstack.h"
25 #include "expression.h"
31 #include "gdb_string.h"
36 #include "cp-support.h"
38 #include "python/python.h"
39 #include "exceptions.h"
41 /* Controls printing of vtbl's. */
43 show_vtblprint (struct ui_file *file, int from_tty,
44 struct cmd_list_element *c, const char *value)
46 fprintf_filtered (file, _("\
47 Printing of C++ virtual function tables is %s.\n"),
51 /* Controls looking up an object's derived type using what we find in
54 show_objectprint (struct ui_file *file, int from_tty,
55 struct cmd_list_element *c,
58 fprintf_filtered (file, _("\
59 Printing of object's derived type based on vtable info is %s.\n"),
64 show_static_field_print (struct ui_file *file, int from_tty,
65 struct cmd_list_element *c,
68 fprintf_filtered (file,
69 _("Printing of C++ static members is %s.\n"),
74 static struct obstack dont_print_vb_obstack;
75 static struct obstack dont_print_statmem_obstack;
76 static struct obstack dont_print_stat_array_obstack;
78 extern void _initialize_cp_valprint (void);
80 static void cp_print_static_field (struct type *, struct value *,
81 struct ui_file *, int,
82 const struct value_print_options *);
84 static void cp_print_value (struct type *, struct type *,
85 const gdb_byte *, int,
86 CORE_ADDR, struct ui_file *,
87 int, const struct value *,
88 const struct value_print_options *,
92 /* GCC versions after 2.4.5 use this. */
93 const char vtbl_ptr_name[] = "__vtbl_ptr_type";
95 /* Return truth value for assertion that TYPE is of the type
96 "pointer to virtual function". */
99 cp_is_vtbl_ptr_type (struct type *type)
101 const char *typename = type_name_no_tag (type);
103 return (typename != NULL && !strcmp (typename, vtbl_ptr_name));
106 /* Return truth value for the assertion that TYPE is of the type
107 "pointer to virtual function table". */
110 cp_is_vtbl_member (struct type *type)
112 /* With older versions of g++, the vtbl field pointed to an array of
113 structures. Nowadays it points directly to the structure. */
114 if (TYPE_CODE (type) == TYPE_CODE_PTR)
116 type = TYPE_TARGET_TYPE (type);
117 if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
119 type = TYPE_TARGET_TYPE (type);
120 if (TYPE_CODE (type) == TYPE_CODE_STRUCT /* if not using thunks */
121 || TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
123 /* Virtual functions tables are full of pointers
124 to virtual functions. */
125 return cp_is_vtbl_ptr_type (type);
128 else if (TYPE_CODE (type) == TYPE_CODE_STRUCT) /* if not using thunks */
130 return cp_is_vtbl_ptr_type (type);
132 else if (TYPE_CODE (type) == TYPE_CODE_PTR) /* if using thunks */
134 /* The type name of the thunk pointer is NULL when using
135 dwarf2. We could test for a pointer to a function, but
136 there is no type info for the virtual table either, so it
138 return cp_is_vtbl_ptr_type (type);
144 /* Mutually recursive subroutines of cp_print_value and c_val_print to
145 print out a structure's fields: cp_print_value_fields and
148 TYPE, VALADDR, ADDRESS, STREAM, RECURSE, and OPTIONS have the same
149 meanings as in cp_print_value and c_val_print.
151 2nd argument REAL_TYPE is used to carry over the type of the
152 derived class across the recursion to base classes.
154 DONT_PRINT is an array of baseclass types that we should not print,
155 or zero if called from top level. */
158 cp_print_value_fields (struct type *type, struct type *real_type,
159 const gdb_byte *valaddr, int offset,
160 CORE_ADDR address, struct ui_file *stream,
161 int recurse, const struct value *val,
162 const struct value_print_options *options,
163 struct type **dont_print_vb,
164 int dont_print_statmem)
166 int i, len, n_baseclasses;
168 static int last_set_recurse = -1;
170 CHECK_TYPEDEF (type);
174 /* Any object can be left on obstacks only during an unexpected
177 if (obstack_object_size (&dont_print_statmem_obstack) > 0)
179 obstack_free (&dont_print_statmem_obstack, NULL);
180 obstack_begin (&dont_print_statmem_obstack,
181 32 * sizeof (CORE_ADDR));
183 if (obstack_object_size (&dont_print_stat_array_obstack) > 0)
185 obstack_free (&dont_print_stat_array_obstack, NULL);
186 obstack_begin (&dont_print_stat_array_obstack,
187 32 * sizeof (struct type *));
191 fprintf_filtered (stream, "{");
192 len = TYPE_NFIELDS (type);
193 n_baseclasses = TYPE_N_BASECLASSES (type);
195 /* First, print out baseclasses such that we don't print
196 duplicates of virtual baseclasses. */
198 if (n_baseclasses > 0)
199 cp_print_value (type, real_type, valaddr,
200 offset, address, stream,
201 recurse + 1, val, options,
204 /* Second, print out data fields */
206 /* If there are no data fields, skip this part */
207 if (len == n_baseclasses || !len)
208 fprintf_filtered (stream, "<No data fields>");
211 int statmem_obstack_initial_size = 0;
212 int stat_array_obstack_initial_size = 0;
214 if (dont_print_statmem == 0)
216 statmem_obstack_initial_size =
217 obstack_object_size (&dont_print_statmem_obstack);
219 if (last_set_recurse != recurse)
221 stat_array_obstack_initial_size =
222 obstack_object_size (&dont_print_stat_array_obstack);
224 last_set_recurse = recurse;
228 for (i = n_baseclasses; i < len; i++)
230 /* If requested, skip printing of static fields. */
231 if (!options->static_field_print
232 && field_is_static (&TYPE_FIELD (type, i)))
236 fprintf_filtered (stream, ", ");
237 else if (n_baseclasses > 0)
241 fprintf_filtered (stream, "\n");
242 print_spaces_filtered (2 + 2 * recurse, stream);
243 fputs_filtered ("members of ", stream);
244 fputs_filtered (type_name_no_tag (type), stream);
245 fputs_filtered (": ", stream);
252 fprintf_filtered (stream, "\n");
253 print_spaces_filtered (2 + 2 * recurse, stream);
257 wrap_here (n_spaces (2 + 2 * recurse));
259 if (options->inspect_it)
261 if (TYPE_CODE (TYPE_FIELD_TYPE (type, i)) == TYPE_CODE_PTR)
262 fputs_filtered ("\"( ptr \"", stream);
264 fputs_filtered ("\"( nodef \"", stream);
265 if (field_is_static (&TYPE_FIELD (type, i)))
266 fputs_filtered ("static ", stream);
267 fprintf_symbol_filtered (stream,
268 TYPE_FIELD_NAME (type, i),
269 current_language->la_language,
270 DMGL_PARAMS | DMGL_ANSI);
271 fputs_filtered ("\" \"", stream);
272 fprintf_symbol_filtered (stream,
273 TYPE_FIELD_NAME (type, i),
274 current_language->la_language,
275 DMGL_PARAMS | DMGL_ANSI);
276 fputs_filtered ("\") \"", stream);
280 annotate_field_begin (TYPE_FIELD_TYPE (type, i));
282 if (field_is_static (&TYPE_FIELD (type, i)))
283 fputs_filtered ("static ", stream);
284 fprintf_symbol_filtered (stream,
285 TYPE_FIELD_NAME (type, i),
286 current_language->la_language,
287 DMGL_PARAMS | DMGL_ANSI);
288 annotate_field_name_end ();
289 /* Do not print leading '=' in case of anonymous
291 if (strcmp (TYPE_FIELD_NAME (type, i), ""))
292 fputs_filtered (" = ", stream);
293 annotate_field_value ();
296 if (!field_is_static (&TYPE_FIELD (type, i))
297 && TYPE_FIELD_PACKED (type, i))
301 /* Bitfields require special handling, especially due to
302 byte order problems. */
303 if (TYPE_FIELD_IGNORE (type, i))
305 fputs_filtered ("<optimized out or zero length>", stream);
307 else if (value_bits_synthetic_pointer (val,
308 TYPE_FIELD_BITPOS (type,
310 TYPE_FIELD_BITSIZE (type,
313 fputs_filtered (_("<synthetic pointer>"), stream);
315 else if (!value_bits_valid (val,
316 TYPE_FIELD_BITPOS (type, i),
317 TYPE_FIELD_BITSIZE (type, i)))
319 val_print_optimized_out (stream);
323 struct value_print_options opts = *options;
327 v = value_field_bitfield (type, i, valaddr, offset, val);
329 common_val_print (v, stream, recurse + 1, &opts,
335 if (TYPE_FIELD_IGNORE (type, i))
337 fputs_filtered ("<optimized out or zero length>",
340 else if (field_is_static (&TYPE_FIELD (type, i)))
342 volatile struct gdb_exception ex;
343 struct value *v = NULL;
345 TRY_CATCH (ex, RETURN_MASK_ERROR)
347 v = value_static_field (type, i);
351 fprintf_filtered (stream,
352 _("<error reading variable: %s>"),
355 val_print_optimized_out (stream);
357 cp_print_static_field (TYPE_FIELD_TYPE (type, i),
358 v, stream, recurse + 1,
361 else if (i == TYPE_VPTR_FIELDNO (type))
364 = extract_typed_address (valaddr + offset
365 + TYPE_FIELD_BITSIZE (type, i) / 8,
366 TYPE_FIELD_TYPE (type, i));
368 print_function_pointer_address (get_type_arch (type),
370 options->addressprint);
374 struct value_print_options opts = *options;
377 val_print (TYPE_FIELD_TYPE (type, i),
379 offset + TYPE_FIELD_BITPOS (type, i) / 8,
381 stream, recurse + 1, val, &opts,
385 annotate_field_end ();
388 if (dont_print_statmem == 0)
390 int obstack_final_size =
391 obstack_object_size (&dont_print_statmem_obstack);
393 if (obstack_final_size > statmem_obstack_initial_size)
395 /* In effect, a pop of the printed-statics stack. */
398 obstack_next_free (&dont_print_statmem_obstack) -
399 (obstack_final_size - statmem_obstack_initial_size);
401 obstack_free (&dont_print_statmem_obstack,
405 if (last_set_recurse != recurse)
407 int obstack_final_size =
408 obstack_object_size (&dont_print_stat_array_obstack);
410 if (obstack_final_size > stat_array_obstack_initial_size)
413 obstack_next_free (&dont_print_stat_array_obstack)
414 - (obstack_final_size
415 - stat_array_obstack_initial_size);
417 obstack_free (&dont_print_stat_array_obstack,
420 last_set_recurse = -1;
426 fprintf_filtered (stream, "\n");
427 print_spaces_filtered (2 * recurse, stream);
429 } /* if there are data fields */
431 fprintf_filtered (stream, "}");
434 /* Like cp_print_value_fields, but find the runtime type of the object
435 and pass it as the `real_type' argument to cp_print_value_fields.
436 This function is a hack to work around the fact that
437 common_val_print passes the embedded offset to val_print, but not
438 the enclosing type. */
441 cp_print_value_fields_rtti (struct type *type,
442 const gdb_byte *valaddr, int offset,
444 struct ui_file *stream, int recurse,
445 const struct value *val,
446 const struct value_print_options *options,
447 struct type **dont_print_vb,
448 int dont_print_statmem)
450 struct type *real_type = NULL;
452 /* We require all bits to be valid in order to attempt a
454 if (value_bits_valid (val, TARGET_CHAR_BIT * offset,
455 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
458 int full, top, using_enc;
460 /* Ugh, we have to convert back to a value here. */
461 value = value_from_contents_and_address (type, valaddr + offset,
463 /* We don't actually care about most of the result here -- just
464 the type. We already have the correct offset, due to how
465 val_print was initially called. */
466 real_type = value_rtti_type (value, &full, &top, &using_enc);
472 cp_print_value_fields (type, real_type, valaddr, offset,
473 address, stream, recurse, val, options,
474 dont_print_vb, dont_print_statmem);
477 /* Special val_print routine to avoid printing multiple copies of
478 virtual baseclasses. */
481 cp_print_value (struct type *type, struct type *real_type,
482 const gdb_byte *valaddr, int offset,
483 CORE_ADDR address, struct ui_file *stream,
484 int recurse, const struct value *val,
485 const struct value_print_options *options,
486 struct type **dont_print_vb)
488 struct type **last_dont_print
489 = (struct type **) obstack_next_free (&dont_print_vb_obstack);
490 struct obstack tmp_obstack = dont_print_vb_obstack;
491 int i, n_baseclasses = TYPE_N_BASECLASSES (type);
493 struct type *thistype;
495 if (dont_print_vb == 0)
497 /* If we're at top level, carve out a completely fresh chunk of
498 the obstack and use that until this particular invocation
500 /* Bump up the high-water mark. Now alpha is omega. */
501 obstack_finish (&dont_print_vb_obstack);
504 for (i = 0; i < n_baseclasses; i++)
508 struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
509 const char *basename = TYPE_NAME (baseclass);
510 const gdb_byte *base_valaddr = NULL;
511 const struct value *base_val = NULL;
512 volatile struct gdb_exception ex;
514 if (BASETYPE_VIA_VIRTUAL (type, i))
516 struct type **first_dont_print
517 = (struct type **) obstack_base (&dont_print_vb_obstack);
519 int j = (struct type **)
520 obstack_next_free (&dont_print_vb_obstack) - first_dont_print;
523 if (baseclass == first_dont_print[j])
526 obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
530 thistype = real_type;
532 TRY_CATCH (ex, RETURN_MASK_ERROR)
534 boffset = baseclass_offset (type, i, valaddr, offset, address, val);
536 if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
538 else if (ex.reason < 0)
544 if (BASETYPE_VIA_VIRTUAL (type, i))
546 /* The virtual base class pointer might have been
547 clobbered by the user program. Make sure that it
548 still points to a valid memory location. */
550 if ((boffset + offset) < 0
551 || (boffset + offset) >= TYPE_LENGTH (real_type))
553 /* FIXME (alloca): unsafe if baseclass is really
555 gdb_byte *buf = alloca (TYPE_LENGTH (baseclass));
557 if (target_read_memory (address + boffset, buf,
558 TYPE_LENGTH (baseclass)) != 0)
560 base_val = value_from_contents_and_address (baseclass,
565 thistype = baseclass;
566 base_valaddr = value_contents_for_printing_const (base_val);
570 base_valaddr = valaddr;
576 base_valaddr = valaddr;
581 /* Now do the printing. */
584 fprintf_filtered (stream, "\n");
585 print_spaces_filtered (2 * recurse, stream);
587 fputs_filtered ("<", stream);
588 /* Not sure what the best notation is in the case where there is
589 no baseclass name. */
590 fputs_filtered (basename ? basename : "", stream);
591 fputs_filtered ("> = ", stream);
594 val_print_unavailable (stream);
596 val_print_invalid_address (stream);
601 /* Attempt to run the Python pretty-printers on the
602 baseclass if possible. */
604 result = apply_val_pretty_printer (baseclass, base_valaddr,
605 thisoffset + boffset,
606 value_address (base_val),
607 stream, recurse, base_val,
608 options, current_language);
613 cp_print_value_fields (baseclass, thistype, base_valaddr,
614 thisoffset + boffset,
615 value_address (base_val),
616 stream, recurse, base_val, options,
618 obstack_base (&dont_print_vb_obstack)),
621 fputs_filtered (", ", stream);
627 if (dont_print_vb == 0)
629 /* Free the space used to deal with the printing
630 of this type from top level. */
631 obstack_free (&dont_print_vb_obstack, last_dont_print);
632 /* Reset watermark so that we can continue protecting
633 ourselves from whatever we were protecting ourselves. */
634 dont_print_vb_obstack = tmp_obstack;
638 /* Print value of a static member. To avoid infinite recursion when
639 printing a class that contains a static instance of the class, we
640 keep the addresses of all printed static member classes in an
641 obstack and refuse to print them more than once.
643 VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
644 have the same meanings as in c_val_print. */
647 cp_print_static_field (struct type *type,
649 struct ui_file *stream,
651 const struct value_print_options *options)
653 struct value_print_options opts;
655 if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
657 CORE_ADDR *first_dont_print;
662 = (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
663 i = obstack_object_size (&dont_print_statmem_obstack)
664 / sizeof (CORE_ADDR);
668 if (value_address (val) == first_dont_print[i])
670 fputs_filtered ("<same as static member of an already"
677 addr = value_address (val);
678 obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
680 CHECK_TYPEDEF (type);
681 cp_print_value_fields (type, value_enclosing_type (val),
682 value_contents_for_printing (val),
683 value_embedded_offset (val), addr,
684 stream, recurse, val,
689 if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
691 struct type **first_dont_print;
693 struct type *target_type = TYPE_TARGET_TYPE (type);
696 = (struct type **) obstack_base (&dont_print_stat_array_obstack);
697 i = obstack_object_size (&dont_print_stat_array_obstack)
698 / sizeof (struct type *);
702 if (target_type == first_dont_print[i])
704 fputs_filtered ("<same as static member of an already"
711 obstack_grow (&dont_print_stat_array_obstack,
712 (char *) &target_type,
713 sizeof (struct type *));
718 val_print (type, value_contents_for_printing (val),
719 value_embedded_offset (val),
721 stream, recurse, val,
722 &opts, current_language);
726 /* Find the field in *DOMAIN, or its non-virtual base classes, with
727 bit offset OFFSET. Set *DOMAIN to the containing type and *FIELDNO
728 to the containing field number. If OFFSET is not exactly at the
729 start of some field, set *DOMAIN to NULL. */
732 cp_find_class_member (struct type **domain_p, int *fieldno,
739 *domain_p = check_typedef (*domain_p);
741 len = TYPE_NFIELDS (domain);
743 for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
745 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
748 if (offset == bitpos)
755 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
757 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
758 LONGEST bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (domain, i));
760 if (offset >= bitpos && offset < bitpos + bitsize)
762 *domain_p = TYPE_FIELD_TYPE (domain, i);
763 cp_find_class_member (domain_p, fieldno, offset - bitpos);
772 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
773 struct ui_file *stream, char *prefix)
775 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
777 /* VAL is a byte offset into the structure type DOMAIN.
778 Find the name of the field for that offset and
780 struct type *domain = TYPE_DOMAIN_TYPE (type);
782 unsigned int fieldno;
784 val = extract_signed_integer (valaddr,
788 /* Pointers to data members are usually byte offsets into an object.
789 Because a data member can have offset zero, and a NULL pointer to
790 member must be distinct from any valid non-NULL pointer to
791 member, either the value is biased or the NULL value has a
792 special representation; both are permitted by ISO C++. HP aCC
793 used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
794 and other compilers which use the Itanium ABI use -1 as the NULL
795 value. GDB only supports that last form; to add support for
796 another form, make this into a cp-abi hook. */
800 fprintf_filtered (stream, "NULL");
804 cp_find_class_member (&domain, &fieldno, val << 3);
810 fputs_filtered (prefix, stream);
811 name = type_name_no_tag (domain);
813 fputs_filtered (name, stream);
815 c_type_print_base (domain, stream, 0, 0);
816 fprintf_filtered (stream, "::");
817 fputs_filtered (TYPE_FIELD_NAME (domain, fieldno), stream);
820 fprintf_filtered (stream, "%ld", (long) val);
825 _initialize_cp_valprint (void)
827 add_setshow_boolean_cmd ("static-members", class_support,
828 &user_print_options.static_field_print, _("\
829 Set printing of C++ static members."), _("\
830 Show printing of C++ static members."), NULL,
832 show_static_field_print,
833 &setprintlist, &showprintlist);
835 add_setshow_boolean_cmd ("vtbl", class_support,
836 &user_print_options.vtblprint, _("\
837 Set printing of C++ virtual function tables."), _("\
838 Show printing of C++ virtual function tables."), NULL,
841 &setprintlist, &showprintlist);
843 add_setshow_boolean_cmd ("object", class_support,
844 &user_print_options.objectprint, _("\
845 Set printing of object's derived type based on vtable info."), _("\
846 Show printing of object's derived type based on vtable info."), NULL,
849 &setprintlist, &showprintlist);
851 obstack_begin (&dont_print_stat_array_obstack,
852 32 * sizeof (struct type *));
853 obstack_begin (&dont_print_statmem_obstack,
854 32 * sizeof (CORE_ADDR));
855 obstack_begin (&dont_print_vb_obstack,
856 32 * sizeof (struct type *));