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))
363 int i_offset = offset + TYPE_FIELD_BITPOS (type, i) / 8;
364 struct type *i_type = TYPE_FIELD_TYPE (type, i);
366 if (valprint_check_validity (stream, i_type, i_offset, val))
370 addr = extract_typed_address (valaddr + i_offset, i_type);
371 print_function_pointer_address (options,
372 get_type_arch (type),
378 struct value_print_options opts = *options;
381 val_print (TYPE_FIELD_TYPE (type, i),
383 offset + TYPE_FIELD_BITPOS (type, i) / 8,
385 stream, recurse + 1, val, &opts,
389 annotate_field_end ();
392 if (dont_print_statmem == 0)
394 int obstack_final_size =
395 obstack_object_size (&dont_print_statmem_obstack);
397 if (obstack_final_size > statmem_obstack_initial_size)
399 /* In effect, a pop of the printed-statics stack. */
402 obstack_next_free (&dont_print_statmem_obstack) -
403 (obstack_final_size - statmem_obstack_initial_size);
405 obstack_free (&dont_print_statmem_obstack,
409 if (last_set_recurse != recurse)
411 int obstack_final_size =
412 obstack_object_size (&dont_print_stat_array_obstack);
414 if (obstack_final_size > stat_array_obstack_initial_size)
417 obstack_next_free (&dont_print_stat_array_obstack)
418 - (obstack_final_size
419 - stat_array_obstack_initial_size);
421 obstack_free (&dont_print_stat_array_obstack,
424 last_set_recurse = -1;
430 fprintf_filtered (stream, "\n");
431 print_spaces_filtered (2 * recurse, stream);
433 } /* if there are data fields */
435 fprintf_filtered (stream, "}");
438 /* Like cp_print_value_fields, but find the runtime type of the object
439 and pass it as the `real_type' argument to cp_print_value_fields.
440 This function is a hack to work around the fact that
441 common_val_print passes the embedded offset to val_print, but not
442 the enclosing type. */
445 cp_print_value_fields_rtti (struct type *type,
446 const gdb_byte *valaddr, int offset,
448 struct ui_file *stream, int recurse,
449 const struct value *val,
450 const struct value_print_options *options,
451 struct type **dont_print_vb,
452 int dont_print_statmem)
454 struct type *real_type = NULL;
456 /* We require all bits to be valid in order to attempt a
458 if (value_bits_valid (val, TARGET_CHAR_BIT * offset,
459 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
462 int full, top, using_enc;
464 /* Ugh, we have to convert back to a value here. */
465 value = value_from_contents_and_address (type, valaddr + offset,
467 /* We don't actually care about most of the result here -- just
468 the type. We already have the correct offset, due to how
469 val_print was initially called. */
470 real_type = value_rtti_type (value, &full, &top, &using_enc);
476 cp_print_value_fields (type, real_type, valaddr, offset,
477 address, stream, recurse, val, options,
478 dont_print_vb, dont_print_statmem);
481 /* Special val_print routine to avoid printing multiple copies of
482 virtual baseclasses. */
485 cp_print_value (struct type *type, struct type *real_type,
486 const gdb_byte *valaddr, int offset,
487 CORE_ADDR address, struct ui_file *stream,
488 int recurse, const struct value *val,
489 const struct value_print_options *options,
490 struct type **dont_print_vb)
492 struct type **last_dont_print
493 = (struct type **) obstack_next_free (&dont_print_vb_obstack);
494 struct obstack tmp_obstack = dont_print_vb_obstack;
495 int i, n_baseclasses = TYPE_N_BASECLASSES (type);
497 struct type *thistype;
499 if (dont_print_vb == 0)
501 /* If we're at top level, carve out a completely fresh chunk of
502 the obstack and use that until this particular invocation
504 /* Bump up the high-water mark. Now alpha is omega. */
505 obstack_finish (&dont_print_vb_obstack);
508 for (i = 0; i < n_baseclasses; i++)
512 struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
513 const char *basename = TYPE_NAME (baseclass);
514 const gdb_byte *base_valaddr = NULL;
515 const struct value *base_val = NULL;
516 volatile struct gdb_exception ex;
518 if (BASETYPE_VIA_VIRTUAL (type, i))
520 struct type **first_dont_print
521 = (struct type **) obstack_base (&dont_print_vb_obstack);
523 int j = (struct type **)
524 obstack_next_free (&dont_print_vb_obstack) - first_dont_print;
527 if (baseclass == first_dont_print[j])
530 obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
534 thistype = real_type;
536 TRY_CATCH (ex, RETURN_MASK_ERROR)
538 boffset = baseclass_offset (type, i, valaddr, offset, address, val);
540 if (ex.reason < 0 && ex.error == NOT_AVAILABLE_ERROR)
542 else if (ex.reason < 0)
548 if (BASETYPE_VIA_VIRTUAL (type, i))
550 /* The virtual base class pointer might have been
551 clobbered by the user program. Make sure that it
552 still points to a valid memory location. */
554 if ((boffset + offset) < 0
555 || (boffset + offset) >= TYPE_LENGTH (real_type))
557 /* FIXME (alloca): unsafe if baseclass is really
559 gdb_byte *buf = alloca (TYPE_LENGTH (baseclass));
561 if (target_read_memory (address + boffset, buf,
562 TYPE_LENGTH (baseclass)) != 0)
564 base_val = value_from_contents_and_address (baseclass,
569 thistype = baseclass;
570 base_valaddr = value_contents_for_printing_const (base_val);
574 base_valaddr = valaddr;
580 base_valaddr = valaddr;
585 /* Now do the printing. */
588 fprintf_filtered (stream, "\n");
589 print_spaces_filtered (2 * recurse, stream);
591 fputs_filtered ("<", stream);
592 /* Not sure what the best notation is in the case where there is
593 no baseclass name. */
594 fputs_filtered (basename ? basename : "", stream);
595 fputs_filtered ("> = ", stream);
598 val_print_unavailable (stream);
600 val_print_invalid_address (stream);
605 /* Attempt to run the Python pretty-printers on the
606 baseclass if possible. */
608 result = apply_val_pretty_printer (baseclass, base_valaddr,
609 thisoffset + boffset,
610 value_address (base_val),
611 stream, recurse, base_val,
612 options, current_language);
617 cp_print_value_fields (baseclass, thistype, base_valaddr,
618 thisoffset + boffset,
619 value_address (base_val),
620 stream, recurse, base_val, options,
622 obstack_base (&dont_print_vb_obstack)),
625 fputs_filtered (", ", stream);
631 if (dont_print_vb == 0)
633 /* Free the space used to deal with the printing
634 of this type from top level. */
635 obstack_free (&dont_print_vb_obstack, last_dont_print);
636 /* Reset watermark so that we can continue protecting
637 ourselves from whatever we were protecting ourselves. */
638 dont_print_vb_obstack = tmp_obstack;
642 /* Print value of a static member. To avoid infinite recursion when
643 printing a class that contains a static instance of the class, we
644 keep the addresses of all printed static member classes in an
645 obstack and refuse to print them more than once.
647 VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
648 have the same meanings as in c_val_print. */
651 cp_print_static_field (struct type *type,
653 struct ui_file *stream,
655 const struct value_print_options *options)
657 struct value_print_options opts;
659 if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
661 CORE_ADDR *first_dont_print;
666 = (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
667 i = obstack_object_size (&dont_print_statmem_obstack)
668 / sizeof (CORE_ADDR);
672 if (value_address (val) == first_dont_print[i])
674 fputs_filtered ("<same as static member of an already"
681 addr = value_address (val);
682 obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
684 CHECK_TYPEDEF (type);
685 cp_print_value_fields (type, value_enclosing_type (val),
686 value_contents_for_printing (val),
687 value_embedded_offset (val), addr,
688 stream, recurse, val,
693 if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
695 struct type **first_dont_print;
697 struct type *target_type = TYPE_TARGET_TYPE (type);
700 = (struct type **) obstack_base (&dont_print_stat_array_obstack);
701 i = obstack_object_size (&dont_print_stat_array_obstack)
702 / sizeof (struct type *);
706 if (target_type == first_dont_print[i])
708 fputs_filtered ("<same as static member of an already"
715 obstack_grow (&dont_print_stat_array_obstack,
716 (char *) &target_type,
717 sizeof (struct type *));
722 val_print (type, value_contents_for_printing (val),
723 value_embedded_offset (val),
725 stream, recurse, val,
726 &opts, current_language);
730 /* Find the field in *DOMAIN, or its non-virtual base classes, with
731 bit offset OFFSET. Set *DOMAIN to the containing type and *FIELDNO
732 to the containing field number. If OFFSET is not exactly at the
733 start of some field, set *DOMAIN to NULL. */
736 cp_find_class_member (struct type **domain_p, int *fieldno,
743 *domain_p = check_typedef (*domain_p);
745 len = TYPE_NFIELDS (domain);
747 for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
749 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
752 if (offset == bitpos)
759 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
761 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
762 LONGEST bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (domain, i));
764 if (offset >= bitpos && offset < bitpos + bitsize)
766 *domain_p = TYPE_FIELD_TYPE (domain, i);
767 cp_find_class_member (domain_p, fieldno, offset - bitpos);
776 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
777 struct ui_file *stream, char *prefix)
779 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
781 /* VAL is a byte offset into the structure type DOMAIN.
782 Find the name of the field for that offset and
784 struct type *domain = TYPE_DOMAIN_TYPE (type);
786 unsigned int fieldno;
788 val = extract_signed_integer (valaddr,
792 /* Pointers to data members are usually byte offsets into an object.
793 Because a data member can have offset zero, and a NULL pointer to
794 member must be distinct from any valid non-NULL pointer to
795 member, either the value is biased or the NULL value has a
796 special representation; both are permitted by ISO C++. HP aCC
797 used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
798 and other compilers which use the Itanium ABI use -1 as the NULL
799 value. GDB only supports that last form; to add support for
800 another form, make this into a cp-abi hook. */
804 fprintf_filtered (stream, "NULL");
808 cp_find_class_member (&domain, &fieldno, val << 3);
814 fputs_filtered (prefix, stream);
815 name = type_name_no_tag (domain);
817 fputs_filtered (name, stream);
819 c_type_print_base (domain, stream, 0, 0);
820 fprintf_filtered (stream, "::");
821 fputs_filtered (TYPE_FIELD_NAME (domain, fieldno), stream);
824 fprintf_filtered (stream, "%ld", (long) val);
829 _initialize_cp_valprint (void)
831 add_setshow_boolean_cmd ("static-members", class_support,
832 &user_print_options.static_field_print, _("\
833 Set printing of C++ static members."), _("\
834 Show printing of C++ static members."), NULL,
836 show_static_field_print,
837 &setprintlist, &showprintlist);
839 add_setshow_boolean_cmd ("vtbl", class_support,
840 &user_print_options.vtblprint, _("\
841 Set printing of C++ virtual function tables."), _("\
842 Show printing of C++ virtual function tables."), NULL,
845 &setprintlist, &showprintlist);
847 add_setshow_boolean_cmd ("object", class_support,
848 &user_print_options.objectprint, _("\
849 Set printing of object's derived type based on vtable info."), _("\
850 Show printing of object's derived type based on vtable info."), NULL,
853 &setprintlist, &showprintlist);
855 obstack_begin (&dont_print_stat_array_obstack,
856 32 * sizeof (struct type *));
857 obstack_begin (&dont_print_statmem_obstack,
858 32 * sizeof (CORE_ADDR));
859 obstack_begin (&dont_print_vb_obstack,
860 32 * sizeof (struct type *));