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 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,
363 struct value_print_options opts
= *options
;
366 val_print (TYPE_FIELD_TYPE (type
, i
),
368 offset
+ TYPE_FIELD_BITPOS (type
, i
) / 8,
370 stream
, recurse
+ 1, val
, &opts
,
374 annotate_field_end ();
377 if (dont_print_statmem
== 0)
379 int obstack_final_size
=
380 obstack_object_size (&dont_print_statmem_obstack
);
382 if (obstack_final_size
> statmem_obstack_initial_size
)
384 /* In effect, a pop of the printed-statics stack. */
387 obstack_next_free (&dont_print_statmem_obstack
) -
388 (obstack_final_size
- statmem_obstack_initial_size
);
390 obstack_free (&dont_print_statmem_obstack
,
394 if (last_set_recurse
!= recurse
)
396 int obstack_final_size
=
397 obstack_object_size (&dont_print_stat_array_obstack
);
399 if (obstack_final_size
> stat_array_obstack_initial_size
)
402 obstack_next_free (&dont_print_stat_array_obstack
)
403 - (obstack_final_size
404 - stat_array_obstack_initial_size
);
406 obstack_free (&dont_print_stat_array_obstack
,
409 last_set_recurse
= -1;
415 fprintf_filtered (stream
, "\n");
416 print_spaces_filtered (2 * recurse
, stream
);
418 } /* if there are data fields */
420 fprintf_filtered (stream
, "}");
423 /* Like cp_print_value_fields, but find the runtime type of the object
424 and pass it as the `real_type' argument to cp_print_value_fields.
425 This function is a hack to work around the fact that
426 common_val_print passes the embedded offset to val_print, but not
427 the enclosing type. */
430 cp_print_value_fields_rtti (struct type
*type
,
431 const gdb_byte
*valaddr
, int offset
,
433 struct ui_file
*stream
, int recurse
,
434 const struct value
*val
,
435 const struct value_print_options
*options
,
436 struct type
**dont_print_vb
,
437 int dont_print_statmem
)
439 struct type
*real_type
= NULL
;
441 /* We require all bits to be valid in order to attempt a
443 if (value_bits_valid (val
, TARGET_CHAR_BIT
* offset
,
444 TARGET_CHAR_BIT
* TYPE_LENGTH (type
)))
447 int full
, top
, using_enc
;
449 /* Ugh, we have to convert back to a value here. */
450 value
= value_from_contents_and_address (type
, valaddr
+ offset
,
452 /* We don't actually care about most of the result here -- just
453 the type. We already have the correct offset, due to how
454 val_print was initially called. */
455 real_type
= value_rtti_type (value
, &full
, &top
, &using_enc
);
461 cp_print_value_fields (type
, real_type
, valaddr
, offset
,
462 address
, stream
, recurse
, val
, options
,
463 dont_print_vb
, dont_print_statmem
);
466 /* Special val_print routine to avoid printing multiple copies of
467 virtual baseclasses. */
470 cp_print_value (struct type
*type
, struct type
*real_type
,
471 const gdb_byte
*valaddr
, int offset
,
472 CORE_ADDR address
, struct ui_file
*stream
,
473 int recurse
, const struct value
*val
,
474 const struct value_print_options
*options
,
475 struct type
**dont_print_vb
)
477 struct type
**last_dont_print
478 = (struct type
**) obstack_next_free (&dont_print_vb_obstack
);
479 struct obstack tmp_obstack
= dont_print_vb_obstack
;
480 int i
, n_baseclasses
= TYPE_N_BASECLASSES (type
);
482 struct type
*thistype
;
484 if (dont_print_vb
== 0)
486 /* If we're at top level, carve out a completely fresh chunk of
487 the obstack and use that until this particular invocation
489 /* Bump up the high-water mark. Now alpha is omega. */
490 obstack_finish (&dont_print_vb_obstack
);
493 for (i
= 0; i
< n_baseclasses
; i
++)
497 struct type
*baseclass
= check_typedef (TYPE_BASECLASS (type
, i
));
498 char *basename
= TYPE_NAME (baseclass
);
499 const gdb_byte
*base_valaddr
= NULL
;
500 const struct value
*base_val
= NULL
;
501 volatile struct gdb_exception ex
;
503 if (BASETYPE_VIA_VIRTUAL (type
, i
))
505 struct type
**first_dont_print
506 = (struct type
**) obstack_base (&dont_print_vb_obstack
);
508 int j
= (struct type
**)
509 obstack_next_free (&dont_print_vb_obstack
) - first_dont_print
;
512 if (baseclass
== first_dont_print
[j
])
515 obstack_ptr_grow (&dont_print_vb_obstack
, baseclass
);
519 thistype
= real_type
;
521 TRY_CATCH (ex
, RETURN_MASK_ERROR
)
523 boffset
= baseclass_offset (type
, i
, valaddr
, offset
, address
, val
);
525 if (ex
.reason
< 0 && ex
.error
== NOT_AVAILABLE_ERROR
)
527 else if (ex
.reason
< 0)
533 if (BASETYPE_VIA_VIRTUAL (type
, i
))
535 /* The virtual base class pointer might have been
536 clobbered by the user program. Make sure that it
537 still points to a valid memory location. */
539 if ((boffset
+ offset
) < 0
540 || (boffset
+ offset
) >= TYPE_LENGTH (real_type
))
542 /* FIXME (alloca): unsafe if baseclass is really
544 gdb_byte
*buf
= alloca (TYPE_LENGTH (baseclass
));
546 if (target_read_memory (address
+ boffset
, buf
,
547 TYPE_LENGTH (baseclass
)) != 0)
549 base_val
= value_from_contents_and_address (baseclass
,
554 thistype
= baseclass
;
555 base_valaddr
= value_contents_for_printing_const (base_val
);
559 base_valaddr
= valaddr
;
565 base_valaddr
= valaddr
;
570 /* Now do the printing. */
573 fprintf_filtered (stream
, "\n");
574 print_spaces_filtered (2 * recurse
, stream
);
576 fputs_filtered ("<", stream
);
577 /* Not sure what the best notation is in the case where there is
578 no baseclass name. */
579 fputs_filtered (basename
? basename
: "", stream
);
580 fputs_filtered ("> = ", stream
);
583 val_print_unavailable (stream
);
585 val_print_invalid_address (stream
);
590 /* Attempt to run the Python pretty-printers on the
591 baseclass if possible. */
593 result
= apply_val_pretty_printer (baseclass
, base_valaddr
,
594 thisoffset
+ boffset
,
595 value_address (base_val
),
596 stream
, recurse
, base_val
,
597 options
, current_language
);
602 cp_print_value_fields (baseclass
, thistype
, base_valaddr
,
603 thisoffset
+ boffset
,
604 value_address (base_val
),
605 stream
, recurse
, base_val
, options
,
607 obstack_base (&dont_print_vb_obstack
)),
610 fputs_filtered (", ", stream
);
616 if (dont_print_vb
== 0)
618 /* Free the space used to deal with the printing
619 of this type from top level. */
620 obstack_free (&dont_print_vb_obstack
, last_dont_print
);
621 /* Reset watermark so that we can continue protecting
622 ourselves from whatever we were protecting ourselves. */
623 dont_print_vb_obstack
= tmp_obstack
;
627 /* Print value of a static member. To avoid infinite recursion when
628 printing a class that contains a static instance of the class, we
629 keep the addresses of all printed static member classes in an
630 obstack and refuse to print them more than once.
632 VAL contains the value to print, TYPE, STREAM, RECURSE, and OPTIONS
633 have the same meanings as in c_val_print. */
636 cp_print_static_field (struct type
*type
,
638 struct ui_file
*stream
,
640 const struct value_print_options
*options
)
642 struct value_print_options opts
;
644 if (TYPE_CODE (type
) == TYPE_CODE_STRUCT
)
646 CORE_ADDR
*first_dont_print
;
651 = (CORE_ADDR
*) obstack_base (&dont_print_statmem_obstack
);
652 i
= obstack_object_size (&dont_print_statmem_obstack
)
653 / sizeof (CORE_ADDR
);
657 if (value_address (val
) == first_dont_print
[i
])
659 fputs_filtered ("<same as static member of an already"
666 addr
= value_address (val
);
667 obstack_grow (&dont_print_statmem_obstack
, (char *) &addr
,
669 CHECK_TYPEDEF (type
);
670 cp_print_value_fields (type
, value_enclosing_type (val
),
671 value_contents_for_printing (val
),
672 value_embedded_offset (val
), addr
,
673 stream
, recurse
, val
,
678 if (TYPE_CODE (type
) == TYPE_CODE_ARRAY
)
680 struct type
**first_dont_print
;
682 struct type
*target_type
= TYPE_TARGET_TYPE (type
);
685 = (struct type
**) obstack_base (&dont_print_stat_array_obstack
);
686 i
= obstack_object_size (&dont_print_stat_array_obstack
)
687 / sizeof (struct type
*);
691 if (target_type
== first_dont_print
[i
])
693 fputs_filtered ("<same as static member of an already"
700 obstack_grow (&dont_print_stat_array_obstack
,
701 (char *) &target_type
,
702 sizeof (struct type
*));
707 val_print (type
, value_contents_for_printing (val
),
708 value_embedded_offset (val
),
710 stream
, recurse
, val
,
711 &opts
, current_language
);
715 /* Find the field in *DOMAIN, or its non-virtual base classes, with
716 bit offset OFFSET. Set *DOMAIN to the containing type and *FIELDNO
717 to the containing field number. If OFFSET is not exactly at the
718 start of some field, set *DOMAIN to NULL. */
721 cp_find_class_member (struct type
**domain_p
, int *fieldno
,
728 *domain_p
= check_typedef (*domain_p
);
730 len
= TYPE_NFIELDS (domain
);
732 for (i
= TYPE_N_BASECLASSES (domain
); i
< len
; i
++)
734 LONGEST bitpos
= TYPE_FIELD_BITPOS (domain
, i
);
737 if (offset
== bitpos
)
744 for (i
= 0; i
< TYPE_N_BASECLASSES (domain
); i
++)
746 LONGEST bitpos
= TYPE_FIELD_BITPOS (domain
, i
);
747 LONGEST bitsize
= 8 * TYPE_LENGTH (TYPE_FIELD_TYPE (domain
, i
));
749 if (offset
>= bitpos
&& offset
< bitpos
+ bitsize
)
751 *domain_p
= TYPE_FIELD_TYPE (domain
, i
);
752 cp_find_class_member (domain_p
, fieldno
, offset
- bitpos
);
761 cp_print_class_member (const gdb_byte
*valaddr
, struct type
*type
,
762 struct ui_file
*stream
, char *prefix
)
764 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
766 /* VAL is a byte offset into the structure type DOMAIN.
767 Find the name of the field for that offset and
769 struct type
*domain
= TYPE_DOMAIN_TYPE (type
);
771 unsigned int fieldno
;
773 val
= extract_signed_integer (valaddr
,
777 /* Pointers to data members are usually byte offsets into an object.
778 Because a data member can have offset zero, and a NULL pointer to
779 member must be distinct from any valid non-NULL pointer to
780 member, either the value is biased or the NULL value has a
781 special representation; both are permitted by ISO C++. HP aCC
782 used a bias of 0x20000000; HP cfront used a bias of 1; g++ 3.x
783 and other compilers which use the Itanium ABI use -1 as the NULL
784 value. GDB only supports that last form; to add support for
785 another form, make this into a cp-abi hook. */
789 fprintf_filtered (stream
, "NULL");
793 cp_find_class_member (&domain
, &fieldno
, val
<< 3);
799 fputs_filtered (prefix
, stream
);
800 name
= type_name_no_tag (domain
);
802 fputs_filtered (name
, stream
);
804 c_type_print_base (domain
, stream
, 0, 0);
805 fprintf_filtered (stream
, "::");
806 fputs_filtered (TYPE_FIELD_NAME (domain
, fieldno
), stream
);
809 fprintf_filtered (stream
, "%ld", (long) val
);
814 _initialize_cp_valprint (void)
816 add_setshow_boolean_cmd ("static-members", class_support
,
817 &user_print_options
.static_field_print
, _("\
818 Set printing of C++ static members."), _("\
819 Show printing of C++ static members."), NULL
,
821 show_static_field_print
,
822 &setprintlist
, &showprintlist
);
824 add_setshow_boolean_cmd ("vtbl", class_support
,
825 &user_print_options
.vtblprint
, _("\
826 Set printing of C++ virtual function tables."), _("\
827 Show printing of C++ virtual function tables."), NULL
,
830 &setprintlist
, &showprintlist
);
832 add_setshow_boolean_cmd ("object", class_support
,
833 &user_print_options
.objectprint
, _("\
834 Set printing of object's derived type based on vtable info."), _("\
835 Show printing of object's derived type based on vtable info."), NULL
,
838 &setprintlist
, &showprintlist
);
840 obstack_begin (&dont_print_stat_array_obstack
,
841 32 * sizeof (struct type
*));
842 obstack_begin (&dont_print_statmem_obstack
,
843 32 * sizeof (CORE_ADDR
));
844 obstack_begin (&dont_print_vb_obstack
,
845 32 * sizeof (struct type
*));