1 /* Support for printing C++ values for GDB, the GNU debugger.
3 Copyright (C) 1986, 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1997,
4 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2008, 2009, 2010, 2011
5 Free Software Foundation, Inc.
7 This file is part of GDB.
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.
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.
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/>. */
23 #include "gdb_obstack.h"
26 #include "expression.h"
32 #include "gdb_string.h"
37 #include "cp-support.h"
39 #include "python/python.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 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 struct value *v = value_static_field (type, i);
345 val_print_optimized_out (stream);
347 cp_print_static_field (TYPE_FIELD_TYPE (type, i),
348 v, stream, recurse + 1,
353 struct value_print_options opts = *options;
356 val_print (TYPE_FIELD_TYPE (type, i),
358 offset + TYPE_FIELD_BITPOS (type, i) / 8,
360 stream, recurse + 1, val, &opts,
364 annotate_field_end ();
367 if (dont_print_statmem == 0)
369 int obstack_final_size =
370 obstack_object_size (&dont_print_statmem_obstack);
372 if (obstack_final_size > statmem_obstack_initial_size)
374 /* In effect, a pop of the printed-statics stack. */
377 obstack_next_free (&dont_print_statmem_obstack) -
378 (obstack_final_size - statmem_obstack_initial_size);
380 obstack_free (&dont_print_statmem_obstack,
384 if (last_set_recurse != recurse)
386 int obstack_final_size =
387 obstack_object_size (&dont_print_stat_array_obstack);
389 if (obstack_final_size > stat_array_obstack_initial_size)
392 obstack_next_free (&dont_print_stat_array_obstack)
393 - (obstack_final_size
394 - stat_array_obstack_initial_size);
396 obstack_free (&dont_print_stat_array_obstack,
399 last_set_recurse = -1;
405 fprintf_filtered (stream, "\n");
406 print_spaces_filtered (2 * recurse, stream);
408 } /* if there are data fields */
410 fprintf_filtered (stream, "}");
413 /* Like cp_print_value_fields, but find the runtime type of the object
414 and pass it as the `real_type' argument to cp_print_value_fields.
415 This function is a hack to work around the fact that
416 common_val_print passes the embedded offset to val_print, but not
417 the enclosing type. */
420 cp_print_value_fields_rtti (struct type *type,
421 const gdb_byte *valaddr, int offset,
423 struct ui_file *stream, int recurse,
424 const struct value *val,
425 const struct value_print_options *options,
426 struct type **dont_print_vb,
427 int dont_print_statmem)
429 struct type *real_type = NULL;
431 /* We require all bits to be valid in order to attempt a
433 if (value_bits_valid (val, TARGET_CHAR_BIT * offset,
434 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
437 int full, top, using_enc;
439 /* Ugh, we have to convert back to a value here. */
440 value = value_from_contents_and_address (type, valaddr + offset,
442 /* We don't actually care about most of the result here -- just
443 the type. We already have the correct offset, due to how
444 val_print was initially called. */
445 real_type = value_rtti_type (value, &full, &top, &using_enc);
451 cp_print_value_fields (type, real_type, valaddr, offset,
452 address, stream, recurse, val, options,
453 dont_print_vb, dont_print_statmem);
456 /* Special val_print routine to avoid printing multiple copies of
457 virtual baseclasses. */
460 cp_print_value (struct type *type, struct type *real_type,
461 const gdb_byte *valaddr, int offset,
462 CORE_ADDR address, struct ui_file *stream,
463 int recurse, const struct value *val,
464 const struct value_print_options *options,
465 struct type **dont_print_vb)
467 struct type **last_dont_print
468 = (struct type **) obstack_next_free (&dont_print_vb_obstack);
469 struct obstack tmp_obstack = dont_print_vb_obstack;
470 int i, n_baseclasses = TYPE_N_BASECLASSES (type);
472 struct type *thistype;
474 if (dont_print_vb == 0)
476 /* If we're at top level, carve out a completely fresh chunk of
477 the obstack and use that until this particular invocation
479 /* Bump up the high-water mark. Now alpha is omega. */
480 obstack_finish (&dont_print_vb_obstack);
483 for (i = 0; i < n_baseclasses; i++)
487 struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
488 char *basename = TYPE_NAME (baseclass);
489 const gdb_byte *base_valaddr;
490 const struct value *base_val;
492 if (BASETYPE_VIA_VIRTUAL (type, i))
494 struct type **first_dont_print
495 = (struct type **) obstack_base (&dont_print_vb_obstack);
497 int j = (struct type **)
498 obstack_next_free (&dont_print_vb_obstack) - first_dont_print;
501 if (baseclass == first_dont_print[j])
504 obstack_ptr_grow (&dont_print_vb_obstack, baseclass);
508 thistype = real_type;
510 boffset = baseclass_offset (type, i, valaddr + offset,
512 skip = ((boffset == -1) || (boffset + offset) < 0);
514 if (BASETYPE_VIA_VIRTUAL (type, i))
516 /* The virtual base class pointer might have been clobbered
517 by the user program. Make sure that it still points to a
518 valid memory location. */
521 && ((boffset + offset) < 0
522 || (boffset + offset) >= TYPE_LENGTH (real_type)))
524 /* FIXME (alloca): unsafe if baseclass is really really
526 gdb_byte *buf = alloca (TYPE_LENGTH (baseclass));
528 if (target_read_memory (address + boffset, buf,
529 TYPE_LENGTH (baseclass)) != 0)
531 base_val = value_from_contents_and_address (baseclass,
536 thistype = baseclass;
537 base_valaddr = value_contents_for_printing_const (base_val);
541 base_valaddr = valaddr;
547 base_valaddr = valaddr;
551 /* Now do the printing. */
554 fprintf_filtered (stream, "\n");
555 print_spaces_filtered (2 * recurse, stream);
557 fputs_filtered ("<", stream);
558 /* Not sure what the best notation is in the case where there is
559 no baseclass name. */
560 fputs_filtered (basename ? basename : "", stream);
561 fputs_filtered ("> = ", stream);
565 fprintf_filtered (stream, "<invalid address>");
570 /* Attempt to run the Python pretty-printers on the
571 baseclass if possible. */
573 result = apply_val_pretty_printer (baseclass, base_valaddr,
574 thisoffset + boffset,
575 value_address (base_val),
576 stream, recurse, base_val,
577 options, current_language);
582 cp_print_value_fields (baseclass, thistype, base_valaddr,
583 thisoffset + boffset,
584 value_address (base_val),
585 stream, recurse, base_val, options,
587 obstack_base (&dont_print_vb_obstack)),
590 fputs_filtered (", ", stream);
596 if (dont_print_vb == 0)
598 /* Free the space used to deal with the printing
599 of this type from top level. */
600 obstack_free (&dont_print_vb_obstack, last_dont_print);
601 /* Reset watermark so that we can continue protecting
602 ourselves from whatever we were protecting ourselves. */
603 dont_print_vb_obstack = tmp_obstack;
607 /* Print value of a static member. To avoid infinite recursion when
608 printing a class that contains a static instance of the class, we
609 keep the addresses of all printed static member classes in an
610 obstack and refuse to print them more than once.
612 VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
613 have the same meanings as in c_val_print. */
616 cp_print_static_field (struct type *type,
618 struct ui_file *stream,
620 const struct value_print_options *options)
622 struct value_print_options opts;
624 if (TYPE_CODE (type) == TYPE_CODE_STRUCT)
626 CORE_ADDR *first_dont_print;
631 = (CORE_ADDR *) obstack_base (&dont_print_statmem_obstack);
632 i = obstack_object_size (&dont_print_statmem_obstack)
633 / sizeof (CORE_ADDR);
637 if (value_address (val) == first_dont_print[i])
639 fputs_filtered ("<same as static member of an already"
646 addr = value_address (val);
647 obstack_grow (&dont_print_statmem_obstack, (char *) &addr,
649 CHECK_TYPEDEF (type);
650 cp_print_value_fields (type, value_enclosing_type (val),
651 value_contents_for_printing (val),
652 value_embedded_offset (val), addr,
653 stream, recurse, val,
658 if (TYPE_CODE (type) == TYPE_CODE_ARRAY)
660 struct type **first_dont_print;
662 struct type *target_type = TYPE_TARGET_TYPE (type);
665 = (struct type **) obstack_base (&dont_print_stat_array_obstack);
666 i = obstack_object_size (&dont_print_stat_array_obstack)
667 / sizeof (struct type *);
671 if (target_type == first_dont_print[i])
673 fputs_filtered ("<same as static member of an already"
680 obstack_grow (&dont_print_stat_array_obstack,
681 (char *) &target_type,
682 sizeof (struct type *));
687 val_print (type, value_contents_for_printing (val),
688 value_embedded_offset (val),
690 stream, recurse, val,
691 &opts, current_language);
695 /* Find the field in *DOMAIN, or its non-virtual base classes, with
696 bit offset OFFSET. Set *DOMAIN to the containing type and *FIELDNO
697 to the containing field number. If OFFSET is not exactly at the
698 start of some field, set *DOMAIN to NULL. */
701 cp_find_class_member (struct type **domain_p, int *fieldno,
708 *domain_p = check_typedef (*domain_p);
710 len = TYPE_NFIELDS (domain);
712 for (i = TYPE_N_BASECLASSES (domain); i < len; i++)
714 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
717 if (offset == bitpos)
724 for (i = 0; i < TYPE_N_BASECLASSES (domain); i++)
726 LONGEST bitpos = TYPE_FIELD_BITPOS (domain, i);
727 LONGEST bitsize = 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (domain, i));
729 if (offset >= bitpos && offset < bitpos + bitsize)
731 *domain_p = TYPE_FIELD_TYPE (domain, i);
732 cp_find_class_member (domain_p, fieldno, offset - bitpos);
741 cp_print_class_member (const gdb_byte *valaddr, struct type *type,
742 struct ui_file *stream, char *prefix)
744 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
746 /* VAL is a byte offset into the structure type DOMAIN.
747 Find the name of the field for that offset and
749 struct type *domain = TYPE_DOMAIN_TYPE (type);
751 unsigned int fieldno;
753 val = extract_signed_integer (valaddr,
757 /* Pointers to data members are usually byte offsets into an object.
758 Because a data member can have offset zero, and a NULL pointer to
759 member must be distinct from any valid non-NULL pointer to
760 member, either the value is biased or the NULL value has a
761 special representation; both are permitted by ISO C++. HP aCC
762 used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
763 and other compilers which use the Itanium ABI use -1 as the NULL
764 value. GDB only supports that last form; to add support for
765 another form, make this into a cp-abi hook. */
769 fprintf_filtered (stream, "NULL");
773 cp_find_class_member (&domain, &fieldno, val << 3);
779 fputs_filtered (prefix, stream);
780 name = type_name_no_tag (domain);
782 fputs_filtered (name, stream);
784 c_type_print_base (domain, stream, 0, 0);
785 fprintf_filtered (stream, "::");
786 fputs_filtered (TYPE_FIELD_NAME (domain, fieldno), stream);
789 fprintf_filtered (stream, "%ld", (long) val);
794 _initialize_cp_valprint (void)
796 add_setshow_boolean_cmd ("static-members", class_support,
797 &user_print_options.static_field_print, _("\
798 Set printing of C++ static members."), _("\
799 Show printing of C++ static members."), NULL,
801 show_static_field_print,
802 &setprintlist, &showprintlist);
804 add_setshow_boolean_cmd ("vtbl", class_support,
805 &user_print_options.vtblprint, _("\
806 Set printing of C++ virtual function tables."), _("\
807 Show printing of C++ virtual function tables."), NULL,
810 &setprintlist, &showprintlist);
812 add_setshow_boolean_cmd ("object", class_support,
813 &user_print_options.objectprint, _("\
814 Set printing of object's derived type based on vtable info."), _("\
815 Show printing of object's derived type based on vtable info."), NULL,
818 &setprintlist, &showprintlist);
820 obstack_begin (&dont_print_stat_array_obstack,
821 32 * sizeof (struct type *));
822 obstack_begin (&dont_print_statmem_obstack,
823 32 * sizeof (CORE_ADDR));
824 obstack_begin (&dont_print_vb_obstack,
825 32 * sizeof (struct type *));