1 /* Support for printing C++ values for GDB, the GNU debugger.
3 Copyright (C) 1986-2013 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "gdb_obstack.h"
24 #include "expression.h"
30 #include "gdb_string.h"
35 #include "cp-support.h"
37 #include "python/python.h"
38 #include "exceptions.h"
39 #include "typeprint.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;
213 struct type *vptr_basetype = NULL;
216 if (dont_print_statmem == 0)
218 statmem_obstack_initial_size =
219 obstack_object_size (&dont_print_statmem_obstack);
221 if (last_set_recurse != recurse)
223 stat_array_obstack_initial_size =
224 obstack_object_size (&dont_print_stat_array_obstack);
226 last_set_recurse = recurse;
230 vptr_fieldno = get_vptr_fieldno (type, &vptr_basetype);
231 for (i = n_baseclasses; i < len; i++)
233 /* If requested, skip printing of static fields. */
234 if (!options->static_field_print
235 && field_is_static (&TYPE_FIELD (type, i)))
239 fprintf_filtered (stream, ", ");
240 else if (n_baseclasses > 0)
242 if (options->prettyformat)
244 fprintf_filtered (stream, "\n");
245 print_spaces_filtered (2 + 2 * recurse, stream);
246 fputs_filtered ("members of ", stream);
247 fputs_filtered (type_name_no_tag (type), stream);
248 fputs_filtered (": ", stream);
253 if (options->prettyformat)
255 fprintf_filtered (stream, "\n");
256 print_spaces_filtered (2 + 2 * recurse, stream);
260 wrap_here (n_spaces (2 + 2 * recurse));
263 annotate_field_begin (TYPE_FIELD_TYPE (type, i));
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 annotate_field_name_end ();
272 /* Do not print leading '=' in case of anonymous
274 if (strcmp (TYPE_FIELD_NAME (type, i), ""))
275 fputs_filtered (" = ", stream);
276 annotate_field_value ();
278 if (!field_is_static (&TYPE_FIELD (type, i))
279 && TYPE_FIELD_PACKED (type, i))
283 /* Bitfields require special handling, especially due to
284 byte order problems. */
285 if (TYPE_FIELD_IGNORE (type, i))
287 fputs_filtered ("<optimized out or zero length>", stream);
289 else if (value_bits_synthetic_pointer (val,
290 TYPE_FIELD_BITPOS (type,
292 TYPE_FIELD_BITSIZE (type,
295 fputs_filtered (_("<synthetic pointer>"), stream);
297 else if (!value_bits_valid (val,
298 TYPE_FIELD_BITPOS (type, i),
299 TYPE_FIELD_BITSIZE (type, i)))
301 val_print_optimized_out (val, stream);
305 struct value_print_options opts = *options;
309 v = value_field_bitfield (type, i, valaddr, offset, val);
311 common_val_print (v, stream, recurse + 1, &opts,
317 if (TYPE_FIELD_IGNORE (type, i))
319 fputs_filtered ("<optimized out or zero length>",
322 else if (field_is_static (&TYPE_FIELD (type, i)))
324 volatile struct gdb_exception ex;
325 struct value *v = NULL;
327 TRY_CATCH (ex, RETURN_MASK_ERROR)
329 v = value_static_field (type, i);
333 fprintf_filtered (stream,
334 _("<error reading variable: %s>"),
336 cp_print_static_field (TYPE_FIELD_TYPE (type, i),
337 v, stream, recurse + 1,
340 else if (i == vptr_fieldno && type == vptr_basetype)
342 int i_offset = offset + TYPE_FIELD_BITPOS (type, i) / 8;
343 struct type *i_type = TYPE_FIELD_TYPE (type, i);
345 if (valprint_check_validity (stream, i_type, i_offset, val))
349 addr = extract_typed_address (valaddr + i_offset, i_type);
350 print_function_pointer_address (options,
351 get_type_arch (type),
357 struct value_print_options opts = *options;
360 val_print (TYPE_FIELD_TYPE (type, i),
362 offset + TYPE_FIELD_BITPOS (type, i) / 8,
364 stream, recurse + 1, val, &opts,
368 annotate_field_end ();
371 if (dont_print_statmem == 0)
373 int obstack_final_size =
374 obstack_object_size (&dont_print_statmem_obstack);
376 if (obstack_final_size > statmem_obstack_initial_size)
378 /* In effect, a pop of the printed-statics stack. */
381 obstack_next_free (&dont_print_statmem_obstack) -
382 (obstack_final_size - statmem_obstack_initial_size);
384 obstack_free (&dont_print_statmem_obstack,
388 if (last_set_recurse != recurse)
390 int obstack_final_size =
391 obstack_object_size (&dont_print_stat_array_obstack);
393 if (obstack_final_size > stat_array_obstack_initial_size)
396 obstack_next_free (&dont_print_stat_array_obstack)
397 - (obstack_final_size
398 - stat_array_obstack_initial_size);
400 obstack_free (&dont_print_stat_array_obstack,
403 last_set_recurse = -1;
407 if (options->prettyformat)
409 fprintf_filtered (stream, "\n");
410 print_spaces_filtered (2 * recurse, stream);
412 } /* if there are data fields */
414 fprintf_filtered (stream, "}");
417 /* Like cp_print_value_fields, but find the runtime type of the object
418 and pass it as the `real_type' argument to cp_print_value_fields.
419 This function is a hack to work around the fact that
420 common_val_print passes the embedded offset to val_print, but not
421 the enclosing type. */
424 cp_print_value_fields_rtti (struct type *type,
425 const gdb_byte *valaddr, int offset,
427 struct ui_file *stream, int recurse,
428 const struct value *val,
429 const struct value_print_options *options,
430 struct type **dont_print_vb,
431 int dont_print_statmem)
433 struct type *real_type = NULL;
435 /* We require all bits to be valid in order to attempt a
437 if (value_bits_valid (val, TARGET_CHAR_BIT * offset,
438 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
441 int full, top, using_enc;
443 /* Ugh, we have to convert back to a value here. */
444 value = value_from_contents_and_address (type, valaddr + offset,
446 /* We don't actually care about most of the result here -- just
447 the type. We already have the correct offset, due to how
448 val_print was initially called. */
449 real_type = value_rtti_type (value, &full, &top, &using_enc);
455 cp_print_value_fields (type, real_type, valaddr, offset,
456 address, stream, recurse, val, options,
457 dont_print_vb, dont_print_statmem);
460 /* Special val_print routine to avoid printing multiple copies of
461 virtual baseclasses. */
464 cp_print_value (struct type *type, struct type *real_type,
465 const gdb_byte *valaddr, int offset,
466 CORE_ADDR address, struct ui_file *stream,
467 int recurse, const struct value *val,
468 const struct value_print_options *options,
469 struct type **dont_print_vb)
471 struct type **last_dont_print
472 = (struct type **) obstack_next_free (&dont_print_vb_obstack);
473 struct obstack tmp_obstack = dont_print_vb_obstack;
474 int i, n_baseclasses = TYPE_N_BASECLASSES (type);
476 struct type *thistype;
478 if (dont_print_vb == 0)
480 /* If we're at top level, carve out a completely fresh chunk of
481 the obstack and use that until this particular invocation
483 /* Bump up the high-water mark. Now alpha is omega. */
484 obstack_finish (&dont_print_vb_obstack);
487 for (i = 0; i < n_baseclasses; i++)
491 struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
492 const char *basename = TYPE_NAME (baseclass);
493 const gdb_byte *base_valaddr = NULL;
494 const struct value *base_val = NULL;
495 volatile struct gdb_exception ex;
497 if (BASETYPE_VIA_VIRTUAL (type, i))
499 struct type **first_dont_print
500 = (struct type **) obstack_base (&dont_print_vb_obstack);
502 int j = (struct type **)
503 obstack_next_free (&dont_print_vb_obstack) - first_dont_print;
506 if (baseclass == first_dont_print[j])
509 obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
513 thistype = real_type;
515 TRY_CATCH (ex, RETURN_MASK_ERROR)
517 boffset = baseclass_offset (type, i, valaddr, offset, address, val);
519 if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
521 else if (ex.reason < 0)
527 if (BASETYPE_VIA_VIRTUAL (type, i))
529 /* The virtual base class pointer might have been
530 clobbered by the user program. Make sure that it
531 still points to a valid memory location. */
533 if ((boffset + offset) < 0
534 || (boffset + offset) >= TYPE_LENGTH (real_type))
537 struct cleanup *back_to;
539 buf = xmalloc (TYPE_LENGTH (baseclass));
540 back_to = make_cleanup (xfree, buf);
542 if (target_read_memory (address + boffset, buf,
543 TYPE_LENGTH (baseclass)) != 0)
545 base_val = value_from_contents_and_address (baseclass,
550 thistype = baseclass;
551 base_valaddr = value_contents_for_printing_const (base_val);
552 do_cleanups (back_to);
556 base_valaddr = valaddr;
562 base_valaddr = valaddr;
567 /* Now do the printing. */
568 if (options->prettyformat)
570 fprintf_filtered (stream, "\n");
571 print_spaces_filtered (2 * recurse, stream);
573 fputs_filtered ("<", stream);
574 /* Not sure what the best notation is in the case where there is
575 no baseclass name. */
576 fputs_filtered (basename ? basename : "", stream);
577 fputs_filtered ("> = ", stream);
580 val_print_unavailable (stream);
582 val_print_invalid_address (stream);
587 /* Attempt to run the Python pretty-printers on the
588 baseclass if possible. */
590 result = apply_val_pretty_printer (baseclass, base_valaddr,
591 thisoffset + boffset,
592 value_address (base_val),
593 stream, recurse, base_val,
594 options, current_language);
599 cp_print_value_fields (baseclass, thistype, base_valaddr,
600 thisoffset + boffset,
601 value_address (base_val),
602 stream, recurse, base_val, options,
604 obstack_base (&dont_print_vb_obstack)),
607 fputs_filtered (", ", stream);
613 if (dont_print_vb == 0)
615 /* Free the space used to deal with the printing
616 of this type from top level. */
617 obstack_free (&dont_print_vb_obstack, last_dont_print);
618 /* Reset watermark so that we can continue protecting
619 ourselves from whatever we were protecting ourselves. */
620 dont_print_vb_obstack = tmp_obstack;
624 /* Print value of a static member. To avoid infinite recursion when
625 printing a class that contains a static instance of the class, we
626 keep the addresses of all printed static member classes in an
627 obstack and refuse to print them more than once.
629 VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
630 have the same meanings as in c_val_print. */
633 cp_print_static_field (struct type *type,
635 struct ui_file *stream,
637 const struct value_print_options *options)
639 struct value_print_options opts;
641 if (value_entirely_optimized_out (val))
643 val_print_optimized_out (val, stream);
647 if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
649 CORE_ADDR *first_dont_print;
654 = (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
655 i = obstack_object_size (&dont_print_statmem_obstack)
656 / sizeof (CORE_ADDR);
660 if (value_address (val) == first_dont_print[i])
662 fputs_filtered ("<same as static member of an already"
669 addr = value_address (val);
670 obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
672 CHECK_TYPEDEF (type);
673 cp_print_value_fields (type, value_enclosing_type (val),
674 value_contents_for_printing (val),
675 value_embedded_offset (val), addr,
676 stream, recurse, val,
681 if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
683 struct type **first_dont_print;
685 struct type *target_type = TYPE_TARGET_TYPE (type);
688 = (struct type **) obstack_base (&dont_print_stat_array_obstack);
689 i = obstack_object_size (&dont_print_stat_array_obstack)
690 / sizeof (struct type *);
694 if (target_type == first_dont_print[i])
696 fputs_filtered ("<same as static member of an already"
703 obstack_grow (&dont_print_stat_array_obstack,
704 (char *) &target_type,
705 sizeof (struct type *));
710 val_print (type, value_contents_for_printing (val),
711 value_embedded_offset (val),
713 stream, recurse, val,
714 &opts, current_language);
718 /* Find the field in *DOMAIN, or its non-virtual base classes, with
719 bit offset OFFSET. Set *DOMAIN to the containing type and *FIELDNO
720 to the containing field number. If OFFSET is not exactly at the
721 start of some field, set *DOMAIN to NULL. */
724 cp_find_class_member (struct type **domain_p, int *fieldno,
731 *domain_p = check_typedef (*domain_p);
733 len = TYPE_NFIELDS (domain);
735 for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
737 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
740 if (offset == bitpos)
747 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
749 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
750 LONGEST bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (domain, i));
752 if (offset >= bitpos && offset < bitpos + bitsize)
754 *domain_p = TYPE_FIELD_TYPE (domain, i);
755 cp_find_class_member (domain_p, fieldno, offset - bitpos);
764 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
765 struct ui_file *stream, char *prefix)
767 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
769 /* VAL is a byte offset into the structure type DOMAIN.
770 Find the name of the field for that offset and
772 struct type *domain = TYPE_DOMAIN_TYPE (type);
776 val = extract_signed_integer (valaddr,
780 /* Pointers to data members are usually byte offsets into an object.
781 Because a data member can have offset zero, and a NULL pointer to
782 member must be distinct from any valid non-NULL pointer to
783 member, either the value is biased or the NULL value has a
784 special representation; both are permitted by ISO C++. HP aCC
785 used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
786 and other compilers which use the Itanium ABI use -1 as the NULL
787 value. GDB only supports that last form; to add support for
788 another form, make this into a cp-abi hook. */
792 fprintf_filtered (stream, "NULL");
796 cp_find_class_member (&domain, &fieldno, val << 3);
802 fputs_filtered (prefix, stream);
803 name = type_name_no_tag (domain);
805 fputs_filtered (name, stream);
807 c_type_print_base (domain, stream, 0, 0, &type_print_raw_options);
808 fprintf_filtered (stream, "::");
809 fputs_filtered (TYPE_FIELD_NAME (domain, fieldno), stream);
812 fprintf_filtered (stream, "%ld", (long) val);
817 _initialize_cp_valprint (void)
819 add_setshow_boolean_cmd ("static-members", class_support,
820 &user_print_options.static_field_print, _("\
821 Set printing of C++ static members."), _("\
822 Show printing of C++ static members."), NULL,
824 show_static_field_print,
825 &setprintlist, &showprintlist);
827 add_setshow_boolean_cmd ("vtbl", class_support,
828 &user_print_options.vtblprint, _("\
829 Set printing of C++ virtual function tables."), _("\
830 Show printing of C++ virtual function tables."), NULL,
833 &setprintlist, &showprintlist);
835 add_setshow_boolean_cmd ("object", class_support,
836 &user_print_options.objectprint, _("\
837 Set printing of object's derived type based on vtable info."), _("\
838 Show printing of object's derived type based on vtable info."), NULL,
841 &setprintlist, &showprintlist);
843 obstack_begin (&dont_print_stat_array_obstack,
844 32 * sizeof (struct type *));
845 obstack_begin (&dont_print_statmem_obstack,
846 32 * sizeof (CORE_ADDR));
847 obstack_begin (&dont_print_vb_obstack,
848 32 * sizeof (struct type *));