1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 87, 89, 91, 93, 94, 95, 96, 97, 1998
3 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 2 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, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "gdb_string.h"
35 /* Prototypes for exported functions. */
37 void _initialize_values
PARAMS ((void));
39 /* Prototypes for local functions. */
41 static value_ptr value_headof
PARAMS ((value_ptr
, struct type
*,
44 static void show_values
PARAMS ((char *, int));
46 static void show_convenience
PARAMS ((char *, int));
48 static int vb_match
PARAMS ((struct type
*, int, struct type
*));
50 /* The value-history records all the values printed
51 by print commands during this session. Each chunk
52 records 60 consecutive values. The first chunk on
53 the chain records the most recent values.
54 The total number of values is in value_history_count. */
56 #define VALUE_HISTORY_CHUNK 60
58 struct value_history_chunk
60 struct value_history_chunk
*next
;
61 value_ptr values
[VALUE_HISTORY_CHUNK
];
64 /* Chain of chunks now in use. */
66 static struct value_history_chunk
*value_history_chain
;
68 static int value_history_count
; /* Abs number of last entry stored */
70 /* List of all value objects currently allocated
71 (except for those released by calls to release_value)
72 This is so they can be freed after each command. */
74 static value_ptr all_values
;
76 /* Allocate a value that has the correct length for type TYPE. */
82 register value_ptr val
;
83 struct type
*atype
= check_typedef (type
);
85 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (atype
));
86 VALUE_NEXT (val
) = all_values
;
88 VALUE_TYPE (val
) = type
;
89 VALUE_LVAL (val
) = not_lval
;
90 VALUE_ADDRESS (val
) = 0;
91 VALUE_FRAME (val
) = 0;
92 VALUE_OFFSET (val
) = 0;
93 VALUE_BITPOS (val
) = 0;
94 VALUE_BITSIZE (val
) = 0;
95 VALUE_REGNO (val
) = -1;
97 VALUE_OPTIMIZED_OUT (val
) = 0;
98 VALUE_BFD_SECTION (val
) = NULL
;
103 /* Allocate a value that has the correct length
104 for COUNT repetitions type TYPE. */
107 allocate_repeat_value (type
, count
)
111 int low_bound
= current_language
->string_lower_bound
; /* ??? */
112 /* FIXME-type-allocation: need a way to free this type when we are
114 struct type
*range_type
115 = create_range_type ((struct type
*) NULL
, builtin_type_int
,
116 low_bound
, count
+ low_bound
- 1);
117 /* FIXME-type-allocation: need a way to free this type when we are
119 return allocate_value (create_array_type ((struct type
*) NULL
,
123 /* Return a mark in the value chain. All values allocated after the
124 mark is obtained (except for those released) are subject to being freed
125 if a subsequent value_free_to_mark is passed the mark. */
132 /* Free all values allocated since MARK was obtained by value_mark
133 (except for those released). */
135 value_free_to_mark (mark
)
140 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
142 next
= VALUE_NEXT (val
);
148 /* Free all the values that have been allocated (except for those released).
149 Called after each command, successful or not. */
154 register value_ptr val
, next
;
156 for (val
= all_values
; val
; val
= next
)
158 next
= VALUE_NEXT (val
);
165 /* Remove VAL from the chain all_values
166 so it will not be freed automatically. */
170 register value_ptr val
;
172 register value_ptr v
;
174 if (all_values
== val
)
176 all_values
= val
->next
;
180 for (v
= all_values
; v
; v
= v
->next
)
190 /* Release all values up to mark */
192 value_release_to_mark (mark
)
197 for (val
= next
= all_values
; next
; next
= VALUE_NEXT (next
))
198 if (VALUE_NEXT (next
) == mark
)
200 all_values
= VALUE_NEXT (next
);
201 VALUE_NEXT (next
) = 0;
208 /* Return a copy of the value ARG.
209 It contains the same contents, for same memory address,
210 but it's a different block of storage. */
216 register struct type
*type
= VALUE_TYPE (arg
);
217 register value_ptr val
= allocate_value (type
);
218 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
219 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
220 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
221 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
222 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
223 VALUE_FRAME (val
) = VALUE_FRAME (arg
);
224 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
225 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
226 VALUE_OPTIMIZED_OUT (val
) = VALUE_OPTIMIZED_OUT (arg
);
227 VALUE_BFD_SECTION (val
) = VALUE_BFD_SECTION (arg
);
228 val
->modifiable
= arg
->modifiable
;
229 if (!VALUE_LAZY (val
))
231 memcpy (VALUE_CONTENTS_RAW (val
), VALUE_CONTENTS_RAW (arg
),
232 TYPE_LENGTH (VALUE_TYPE (arg
)));
237 /* Access to the value history. */
239 /* Record a new value in the value history.
240 Returns the absolute history index of the entry.
241 Result of -1 indicates the value was not saved; otherwise it is the
242 value history index of this new item. */
245 record_latest_value (val
)
250 /* We don't want this value to have anything to do with the inferior anymore.
251 In particular, "set $1 = 50" should not affect the variable from which
252 the value was taken, and fast watchpoints should be able to assume that
253 a value on the value history never changes. */
254 if (VALUE_LAZY (val
))
255 value_fetch_lazy (val
);
256 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
257 from. This is a bit dubious, because then *&$1 does not just return $1
258 but the current contents of that location. c'est la vie... */
262 /* Here we treat value_history_count as origin-zero
263 and applying to the value being stored now. */
265 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
268 register struct value_history_chunk
*new
269 = (struct value_history_chunk
*)
270 xmalloc (sizeof (struct value_history_chunk
));
271 memset (new->values
, 0, sizeof new->values
);
272 new->next
= value_history_chain
;
273 value_history_chain
= new;
276 value_history_chain
->values
[i
] = val
;
278 /* Now we regard value_history_count as origin-one
279 and applying to the value just stored. */
281 return ++value_history_count
;
284 /* Return a copy of the value in the history with sequence number NUM. */
287 access_value_history (num
)
290 register struct value_history_chunk
*chunk
;
292 register int absnum
= num
;
295 absnum
+= value_history_count
;
300 error ("The history is empty.");
302 error ("There is only one value in the history.");
304 error ("History does not go back to $$%d.", -num
);
306 if (absnum
> value_history_count
)
307 error ("History has not yet reached $%d.", absnum
);
311 /* Now absnum is always absolute and origin zero. */
313 chunk
= value_history_chain
;
314 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
318 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
321 /* Clear the value history entirely.
322 Must be done when new symbol tables are loaded,
323 because the type pointers become invalid. */
326 clear_value_history ()
328 register struct value_history_chunk
*next
;
330 register value_ptr val
;
332 while (value_history_chain
)
334 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
335 if ((val
= value_history_chain
->values
[i
]) != NULL
)
337 next
= value_history_chain
->next
;
338 free ((PTR
)value_history_chain
);
339 value_history_chain
= next
;
341 value_history_count
= 0;
345 show_values (num_exp
, from_tty
)
350 register value_ptr val
;
355 /* "info history +" should print from the stored position.
356 "info history <exp>" should print around value number <exp>. */
357 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
358 num
= parse_and_eval_address (num_exp
) - 5;
362 /* "info history" means print the last 10 values. */
363 num
= value_history_count
- 9;
369 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
371 val
= access_value_history (i
);
372 printf_filtered ("$%d = ", i
);
373 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
374 printf_filtered ("\n");
377 /* The next "info history +" should start after what we just printed. */
380 /* Hitting just return after this command should do the same thing as
381 "info history +". If num_exp is null, this is unnecessary, since
382 "info history +" is not useful after "info history". */
383 if (from_tty
&& num_exp
)
390 /* Internal variables. These are variables within the debugger
391 that hold values assigned by debugger commands.
392 The user refers to them with a '$' prefix
393 that does not appear in the variable names stored internally. */
395 static struct internalvar
*internalvars
;
397 /* Look up an internal variable with name NAME. NAME should not
398 normally include a dollar sign.
400 If the specified internal variable does not exist,
401 one is created, with a void value. */
404 lookup_internalvar (name
)
407 register struct internalvar
*var
;
409 for (var
= internalvars
; var
; var
= var
->next
)
410 if (STREQ (var
->name
, name
))
413 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
414 var
->name
= concat (name
, NULL
);
415 var
->value
= allocate_value (builtin_type_void
);
416 release_value (var
->value
);
417 var
->next
= internalvars
;
423 value_of_internalvar (var
)
424 struct internalvar
*var
;
426 register value_ptr val
;
428 #ifdef IS_TRAPPED_INTERNALVAR
429 if (IS_TRAPPED_INTERNALVAR (var
->name
))
430 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
433 val
= value_copy (var
->value
);
434 if (VALUE_LAZY (val
))
435 value_fetch_lazy (val
);
436 VALUE_LVAL (val
) = lval_internalvar
;
437 VALUE_INTERNALVAR (val
) = var
;
442 set_internalvar_component (var
, offset
, bitpos
, bitsize
, newval
)
443 struct internalvar
*var
;
444 int offset
, bitpos
, bitsize
;
447 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
449 #ifdef IS_TRAPPED_INTERNALVAR
450 if (IS_TRAPPED_INTERNALVAR (var
->name
))
451 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
455 modify_field (addr
, value_as_long (newval
),
458 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
462 set_internalvar (var
, val
)
463 struct internalvar
*var
;
468 #ifdef IS_TRAPPED_INTERNALVAR
469 if (IS_TRAPPED_INTERNALVAR (var
->name
))
470 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
473 newval
= value_copy (val
);
474 newval
->modifiable
= 1;
476 /* Force the value to be fetched from the target now, to avoid problems
477 later when this internalvar is referenced and the target is gone or
479 if (VALUE_LAZY (newval
))
480 value_fetch_lazy (newval
);
482 /* Begin code which must not call error(). If var->value points to
483 something free'd, an error() obviously leaves a dangling pointer.
484 But we also get a danling pointer if var->value points to
485 something in the value chain (i.e., before release_value is
486 called), because after the error free_all_values will get called before
488 free ((PTR
)var
->value
);
490 release_value (newval
);
491 /* End code which must not call error(). */
495 internalvar_name (var
)
496 struct internalvar
*var
;
501 /* Free all internalvars. Done when new symtabs are loaded,
502 because that makes the values invalid. */
505 clear_internalvars ()
507 register struct internalvar
*var
;
512 internalvars
= var
->next
;
513 free ((PTR
)var
->name
);
514 free ((PTR
)var
->value
);
520 show_convenience (ignore
, from_tty
)
524 register struct internalvar
*var
;
527 for (var
= internalvars
; var
; var
= var
->next
)
529 #ifdef IS_TRAPPED_INTERNALVAR
530 if (IS_TRAPPED_INTERNALVAR (var
->name
))
537 printf_filtered ("$%s = ", var
->name
);
538 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
539 printf_filtered ("\n");
542 printf_unfiltered ("No debugger convenience variables now defined.\n\
543 Convenience variables have names starting with \"$\";\n\
544 use \"set\" as in \"set $foo = 5\" to define them.\n");
547 /* Extract a value as a C number (either long or double).
548 Knows how to convert fixed values to double, or
549 floating values to long.
550 Does not deallocate the value. */
554 register value_ptr val
;
556 /* This coerces arrays and functions, which is necessary (e.g.
557 in disassemble_command). It also dereferences references, which
558 I suspect is the most logical thing to do. */
560 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
564 value_as_double (val
)
565 register value_ptr val
;
570 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
572 error ("Invalid floating value found in program.");
575 /* Extract a value as a C pointer.
576 Does not deallocate the value. */
578 value_as_pointer (val
)
581 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
582 whether we want this to be true eventually. */
584 /* ADDR_BITS_REMOVE is wrong if we are being called for a
585 non-address (e.g. argument to "signal", "info break", etc.), or
586 for pointers to char, in which the low bits *are* significant. */
587 return ADDR_BITS_REMOVE(value_as_long (val
));
589 return value_as_long (val
);
593 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
594 as a long, or as a double, assuming the raw data is described
595 by type TYPE. Knows how to convert different sizes of values
596 and can convert between fixed and floating point. We don't assume
597 any alignment for the raw data. Return value is in host byte order.
599 If you want functions and arrays to be coerced to pointers, and
600 references to be dereferenced, call value_as_long() instead.
602 C++: It is assumed that the front-end has taken care of
603 all matters concerning pointers to members. A pointer
604 to member which reaches here is considered to be equivalent
605 to an INT (or some size). After all, it is only an offset. */
608 unpack_long (type
, valaddr
)
612 register enum type_code code
= TYPE_CODE (type
);
613 register int len
= TYPE_LENGTH (type
);
614 register int nosign
= TYPE_UNSIGNED (type
);
616 if (current_language
->la_language
== language_scm
617 && is_scmvalue_type (type
))
618 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
622 case TYPE_CODE_TYPEDEF
:
623 return unpack_long (check_typedef (type
), valaddr
);
628 case TYPE_CODE_RANGE
:
630 return extract_unsigned_integer (valaddr
, len
);
632 return extract_signed_integer (valaddr
, len
);
635 return extract_floating (valaddr
, len
);
639 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
640 whether we want this to be true eventually. */
641 #ifdef GDB_TARGET_IS_D10V
643 return D10V_MAKE_DADDR(extract_address (valaddr
, len
));
645 return extract_address (valaddr
, len
);
647 case TYPE_CODE_MEMBER
:
648 error ("not implemented: member types in unpack_long");
651 error ("Value can't be converted to integer.");
653 return 0; /* Placate lint. */
656 /* Return a double value from the specified type and address.
657 INVP points to an int which is set to 0 for valid value,
658 1 for invalid value (bad float format). In either case,
659 the returned double is OK to use. Argument is in target
660 format, result is in host format. */
663 unpack_double (type
, valaddr
, invp
)
672 *invp
= 0; /* Assume valid. */
673 CHECK_TYPEDEF (type
);
674 code
= TYPE_CODE (type
);
675 len
= TYPE_LENGTH (type
);
676 nosign
= TYPE_UNSIGNED (type
);
677 if (code
== TYPE_CODE_FLT
)
680 if (INVALID_FLOAT (valaddr
, len
))
683 return 1.234567891011121314;
686 return extract_floating (valaddr
, len
);
690 /* Unsigned -- be sure we compensate for signed LONGEST. */
691 #if !defined (_MSC_VER) || (_MSC_VER > 900)
692 return (ULONGEST
) unpack_long (type
, valaddr
);
694 /* FIXME!!! msvc22 doesn't support unsigned __int64 -> double */
695 return (LONGEST
) unpack_long (type
, valaddr
);
696 #endif /* _MSC_VER */
700 /* Signed -- we are OK with unpack_long. */
701 return unpack_long (type
, valaddr
);
705 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
706 as a CORE_ADDR, assuming the raw data is described by type TYPE.
707 We don't assume any alignment for the raw data. Return value is in
710 If you want functions and arrays to be coerced to pointers, and
711 references to be dereferenced, call value_as_pointer() instead.
713 C++: It is assumed that the front-end has taken care of
714 all matters concerning pointers to members. A pointer
715 to member which reaches here is considered to be equivalent
716 to an INT (or some size). After all, it is only an offset. */
719 unpack_pointer (type
, valaddr
)
723 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
724 whether we want this to be true eventually. */
725 return unpack_long (type
, valaddr
);
728 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
731 value_static_field (type
, fieldno
)
737 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
739 addr
= TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
);
744 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
745 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_NAMESPACE
, 0, NULL
);
748 addr
= SYMBOL_VALUE_ADDRESS (sym
);
749 sect
= SYMBOL_BFD_SECTION (sym
);
750 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
), addr
);
752 return value_at (TYPE_FIELD_TYPE (type
, fieldno
), addr
, sect
);
755 /* Given a value ARG1 (offset by OFFSET bytes)
756 of a struct or union type ARG_TYPE,
757 extract and return the value of one of its (non-static) fields.
758 FIELDNO says which field. */
761 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
762 register value_ptr arg1
;
764 register int fieldno
;
765 register struct type
*arg_type
;
767 register value_ptr v
;
768 register struct type
*type
;
770 CHECK_TYPEDEF (arg_type
);
771 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
773 /* Handle packed fields */
775 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
777 v
= value_from_longest (type
,
778 unpack_field_as_long (arg_type
,
779 VALUE_CONTENTS (arg1
)
782 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
783 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
787 v
= allocate_value (type
);
788 if (VALUE_LAZY (arg1
))
791 memcpy (VALUE_CONTENTS_RAW (v
),
792 VALUE_CONTENTS_RAW (arg1
) + offset
793 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8,
796 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
797 if (VALUE_LVAL (arg1
) == lval_internalvar
)
798 VALUE_LVAL (v
) = lval_internalvar_component
;
799 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
800 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
801 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
805 /* Given a value ARG1 of a struct or union type,
806 extract and return the value of one of its (non-static) fields.
807 FIELDNO says which field. */
810 value_field (arg1
, fieldno
)
811 register value_ptr arg1
;
812 register int fieldno
;
814 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
817 /* Return a non-virtual function as a value.
818 F is the list of member functions which contains the desired method.
819 J is an index into F which provides the desired method. */
822 value_fn_field (arg1p
, f
, j
, type
, offset
)
829 register value_ptr v
;
830 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
833 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
834 0, VAR_NAMESPACE
, 0, NULL
);
838 error ("Internal error: could not find physical method named %s",
839 TYPE_FN_FIELD_PHYSNAME (f, j));
842 v
= allocate_value (ftype
);
843 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
844 VALUE_TYPE (v
) = ftype
;
848 if (type
!= VALUE_TYPE (*arg1p
))
849 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
850 value_addr (*arg1p
)));
852 /* Move the `this' pointer according to the offset.
853 VALUE_OFFSET (*arg1p) += offset;
860 /* Return a virtual function as a value.
861 ARG1 is the object which provides the virtual function
862 table pointer. *ARG1P is side-effected in calling this function.
863 F is the list of member functions which contains the desired virtual
865 J is an index into F which provides the desired virtual function.
867 TYPE is the type in which F is located. */
869 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
876 value_ptr arg1
= *arg1p
;
877 struct type
*type1
= check_typedef (VALUE_TYPE (arg1
));
878 struct type
*entry_type
;
879 /* First, get the virtual function table pointer. That comes
880 with a strange type, so cast it to type `pointer to long' (which
881 should serve just fine as a function type). Then, index into
882 the table, and convert final value to appropriate function type. */
883 value_ptr entry
, vfn
, vtbl
;
884 value_ptr vi
= value_from_longest (builtin_type_int
,
885 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
886 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
887 struct type
*context
;
888 if (fcontext
== NULL
)
889 /* We don't have an fcontext (e.g. the program was compiled with
890 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
891 This won't work right for multiple inheritance, but at least we
892 should do as well as GDB 3.x did. */
893 fcontext
= TYPE_VPTR_BASETYPE (type
);
894 context
= lookup_pointer_type (fcontext
);
895 /* Now context is a pointer to the basetype containing the vtbl. */
896 if (TYPE_TARGET_TYPE (context
) != type1
)
898 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
899 type1
= check_typedef (VALUE_TYPE (arg1
));
903 /* Now context is the basetype containing the vtbl. */
905 /* This type may have been defined before its virtual function table
906 was. If so, fill in the virtual function table entry for the
908 if (TYPE_VPTR_FIELDNO (context
) < 0)
909 fill_in_vptr_fieldno (context
);
911 /* The virtual function table is now an array of structures
912 which have the form { int16 offset, delta; void *pfn; }. */
913 vtbl
= value_primitive_field (arg1
, 0, TYPE_VPTR_FIELDNO (context
),
914 TYPE_VPTR_BASETYPE (context
));
916 /* With older versions of g++, the vtbl field pointed to an array
917 of structures. Nowadays it points directly to the structure. */
918 if (TYPE_CODE (VALUE_TYPE (vtbl
)) == TYPE_CODE_PTR
919 && TYPE_CODE (TYPE_TARGET_TYPE (VALUE_TYPE (vtbl
))) == TYPE_CODE_ARRAY
)
921 /* Handle the case where the vtbl field points to an
922 array of structures. */
923 vtbl
= value_ind (vtbl
);
925 /* Index into the virtual function table. This is hard-coded because
926 looking up a field is not cheap, and it may be important to save
927 time, e.g. if the user has set a conditional breakpoint calling
928 a virtual function. */
929 entry
= value_subscript (vtbl
, vi
);
933 /* Handle the case where the vtbl field points directly to a structure. */
934 vtbl
= value_add (vtbl
, vi
);
935 entry
= value_ind (vtbl
);
938 entry_type
= check_typedef (VALUE_TYPE (entry
));
940 if (TYPE_CODE (entry_type
) == TYPE_CODE_STRUCT
)
942 /* Move the `this' pointer according to the virtual function table. */
943 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0));
945 if (! VALUE_LAZY (arg1
))
947 VALUE_LAZY (arg1
) = 1;
948 value_fetch_lazy (arg1
);
951 vfn
= value_field (entry
, 2);
953 else if (TYPE_CODE (entry_type
) == TYPE_CODE_PTR
)
956 error ("I'm confused: virtual function table has bad type");
957 /* Reinstantiate the function pointer with the correct type. */
958 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
964 /* ARG is a pointer to an object we know to be at least
965 a DTYPE. BTYPE is the most derived basetype that has
966 already been searched (and need not be searched again).
967 After looking at the vtables between BTYPE and DTYPE,
968 return the most derived type we find. The caller must
969 be satisfied when the return value == DTYPE.
971 FIXME-tiemann: should work with dossier entries as well. */
974 value_headof (in_arg
, btype
, dtype
)
976 struct type
*btype
, *dtype
;
978 /* First collect the vtables we must look at for this object. */
979 /* FIXME-tiemann: right now, just look at top-most vtable. */
980 value_ptr arg
, vtbl
, entry
, best_entry
= 0;
982 int offset
, best_offset
= 0;
984 CORE_ADDR pc_for_sym
;
985 char *demangled_name
;
986 struct minimal_symbol
*msymbol
;
988 btype
= TYPE_VPTR_BASETYPE (dtype
);
989 CHECK_TYPEDEF (btype
);
992 arg
= value_cast (lookup_pointer_type (btype
), arg
);
993 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
995 /* Check that VTBL looks like it points to a virtual function table. */
996 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
998 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
999 || !VTBL_PREFIX_P (demangled_name
))
1001 /* If we expected to find a vtable, but did not, let the user
1002 know that we aren't happy, but don't throw an error.
1003 FIXME: there has to be a better way to do this. */
1004 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
1005 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
1006 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
1007 VALUE_TYPE (in_arg
) = error_type
;
1011 /* Now search through the virtual function table. */
1012 entry
= value_ind (vtbl
);
1013 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
1014 for (i
= 1; i
<= nelems
; i
++)
1016 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
1018 /* This won't work if we're using thunks. */
1019 if (TYPE_CODE (check_typedef (VALUE_TYPE (entry
))) != TYPE_CODE_STRUCT
)
1021 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
1022 /* If we use '<=' we can handle single inheritance
1023 * where all offsets are zero - just use the first entry found. */
1024 if (offset
<= best_offset
)
1026 best_offset
= offset
;
1030 /* Move the pointer according to BEST_ENTRY's offset, and figure
1031 out what type we should return as the new pointer. */
1032 if (best_entry
== 0)
1034 /* An alternative method (which should no longer be necessary).
1035 * But we leave it in for future use, when we will hopefully
1036 * have optimizes the vtable to use thunks instead of offsets. */
1037 /* Use the name of vtable itself to extract a base type. */
1038 demangled_name
+= 4; /* Skip _vt$ prefix. */
1042 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
1043 sym
= find_pc_function (pc_for_sym
);
1044 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), DMGL_ANSI
);
1045 *(strchr (demangled_name
, ':')) = '\0';
1047 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
1049 error ("could not find type declaration for `%s'", demangled_name
);
1052 free (demangled_name
);
1053 arg
= value_add (value_cast (builtin_type_int
, arg
),
1054 value_field (best_entry
, 0));
1057 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1061 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1062 function tables, probe ARG's tables (including the vtables
1063 of its baseclasses) to figure out the most derived type that ARG
1064 could actually be a pointer to. */
1067 value_from_vtable_info (arg
, type
)
1071 /* Take care of preliminaries. */
1072 if (TYPE_VPTR_FIELDNO (type
) < 0)
1073 fill_in_vptr_fieldno (type
);
1074 if (TYPE_VPTR_FIELDNO (type
) < 0)
1077 return value_headof (arg
, 0, type
);
1080 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1081 pointer which is for the base class whose type is BASECLASS. */
1084 vb_match (type
, index
, basetype
)
1087 struct type
*basetype
;
1089 struct type
*fieldtype
;
1090 char *name
= TYPE_FIELD_NAME (type
, index
);
1091 char *field_class_name
= NULL
;
1095 /* gcc 2.4 uses _vb$. */
1096 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
1097 field_class_name
= name
+ 4;
1098 /* gcc 2.5 will use __vb_. */
1099 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1100 field_class_name
= name
+ 5;
1102 if (field_class_name
== NULL
)
1103 /* This field is not a virtual base class pointer. */
1106 /* It's a virtual baseclass pointer, now we just need to find out whether
1107 it is for this baseclass. */
1108 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1109 if (fieldtype
== NULL
1110 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1111 /* "Can't happen". */
1114 /* What we check for is that either the types are equal (needed for
1115 nameless types) or have the same name. This is ugly, and a more
1116 elegant solution should be devised (which would probably just push
1117 the ugliness into symbol reading unless we change the stabs format). */
1118 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1121 if (TYPE_NAME (basetype
) != NULL
1122 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1123 && STREQ (TYPE_NAME (basetype
),
1124 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1129 /* Compute the offset of the baseclass which is
1130 the INDEXth baseclass of class TYPE,
1131 for value at VALADDR (in host) at ADDRESS (in target).
1132 The result is the offset of the baseclass value relative
1133 to (the address of)(ARG) + OFFSET.
1135 -1 is returned on error. */
1138 baseclass_offset (type
, index
, valaddr
, address
)
1144 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1146 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1148 /* Must hunt for the pointer to this virtual baseclass. */
1149 register int i
, len
= TYPE_NFIELDS (type
);
1150 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1152 /* First look for the virtual baseclass pointer
1154 for (i
= n_baseclasses
; i
< len
; i
++)
1156 if (vb_match (type
, i
, basetype
))
1159 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1160 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1162 return addr
- (LONGEST
) address
;
1165 /* Not in the fields, so try looking through the baseclasses. */
1166 for (i
= index
+1; i
< n_baseclasses
; i
++)
1169 baseclass_offset (type
, i
, valaddr
, address
);
1177 /* Baseclass is easily computed. */
1178 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1181 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1184 Extracting bits depends on endianness of the machine. Compute the
1185 number of least significant bits to discard. For big endian machines,
1186 we compute the total number of bits in the anonymous object, subtract
1187 off the bit count from the MSB of the object to the MSB of the
1188 bitfield, then the size of the bitfield, which leaves the LSB discard
1189 count. For little endian machines, the discard count is simply the
1190 number of bits from the LSB of the anonymous object to the LSB of the
1193 If the field is signed, we also do sign extension. */
1196 unpack_field_as_long (type
, valaddr
, fieldno
)
1203 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1204 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1206 struct type
*field_type
;
1208 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1209 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1210 CHECK_TYPEDEF (field_type
);
1212 /* Extract bits. See comment above. */
1214 if (BITS_BIG_ENDIAN
)
1215 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1217 lsbcount
= (bitpos
% 8);
1220 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1221 If the field is signed, and is negative, then sign extend. */
1223 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1225 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1227 if (!TYPE_UNSIGNED (field_type
))
1229 if (val
& (valmask
^ (valmask
>> 1)))
1238 /* Modify the value of a bitfield. ADDR points to a block of memory in
1239 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1240 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1241 indicate which bits (in target bit order) comprise the bitfield. */
1244 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1247 int bitpos
, bitsize
;
1251 /* If a negative fieldval fits in the field in question, chop
1252 off the sign extension bits. */
1253 if (bitsize
< (8 * (int) sizeof (fieldval
))
1254 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1255 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1257 /* Warn if value is too big to fit in the field in question. */
1258 if (bitsize
< (8 * (int) sizeof (fieldval
))
1259 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1261 /* FIXME: would like to include fieldval in the message, but
1262 we don't have a sprintf_longest. */
1263 warning ("Value does not fit in %d bits.", bitsize
);
1265 /* Truncate it, otherwise adjoining fields may be corrupted. */
1266 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1269 oword
= extract_signed_integer (addr
, sizeof oword
);
1271 /* Shifting for bit field depends on endianness of the target machine. */
1272 if (BITS_BIG_ENDIAN
)
1273 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1275 /* Mask out old value, while avoiding shifts >= size of oword */
1276 if (bitsize
< 8 * (int) sizeof (oword
))
1277 oword
&= ~(((((ULONGEST
)1) << bitsize
) - 1) << bitpos
);
1279 oword
&= ~((~(ULONGEST
)0) << bitpos
);
1280 oword
|= fieldval
<< bitpos
;
1282 store_signed_integer (addr
, sizeof oword
, oword
);
1285 /* Convert C numbers into newly allocated values */
1288 value_from_longest (type
, num
)
1290 register LONGEST num
;
1292 register value_ptr val
= allocate_value (type
);
1293 register enum type_code code
;
1296 code
= TYPE_CODE (type
);
1297 len
= TYPE_LENGTH (type
);
1301 case TYPE_CODE_TYPEDEF
:
1302 type
= check_typedef (type
);
1305 case TYPE_CODE_CHAR
:
1306 case TYPE_CODE_ENUM
:
1307 case TYPE_CODE_BOOL
:
1308 case TYPE_CODE_RANGE
:
1309 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1314 /* This assumes that all pointers of a given length
1315 have the same form. */
1316 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1320 error ("Unexpected type (%d) encountered for integer constant.", code
);
1326 value_from_double (type
, num
)
1330 register value_ptr val
= allocate_value (type
);
1331 struct type
*base_type
= check_typedef (type
);
1332 register enum type_code code
= TYPE_CODE (base_type
);
1333 register int len
= TYPE_LENGTH (base_type
);
1335 if (code
== TYPE_CODE_FLT
)
1337 store_floating (VALUE_CONTENTS_RAW (val
), len
, num
);
1340 error ("Unexpected type encountered for floating constant.");
1345 /* Deal with the value that is "about to be returned". */
1347 /* Return the value that a function returning now
1348 would be returning to its caller, assuming its type is VALTYPE.
1349 RETBUF is where we look for what ought to be the contents
1350 of the registers (in raw form). This is because it is often
1351 desirable to restore old values to those registers
1352 after saving the contents of interest, and then call
1353 this function using the saved values.
1354 struct_return is non-zero when the function in question is
1355 using the structure return conventions on the machine in question;
1356 0 when it is using the value returning conventions (this often
1357 means returning pointer to where structure is vs. returning value). */
1360 value_being_returned (valtype
, retbuf
, struct_return
)
1361 register struct type
*valtype
;
1362 char retbuf
[REGISTER_BYTES
];
1366 register value_ptr val
;
1369 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1370 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1371 if (struct_return
) {
1372 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1374 error ("Function return value unknown");
1375 return value_at (valtype
, addr
, NULL
);
1379 val
= allocate_value (valtype
);
1380 CHECK_TYPEDEF (valtype
);
1381 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1386 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1387 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1388 and TYPE is the type (which is known to be struct, union or array).
1390 On most machines, the struct convention is used unless we are
1391 using gcc and the type is of a special size. */
1392 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1393 native compiler. GCC 2.3.3 was the last release that did it the
1394 old way. Since gcc2_compiled was not changed, we have no
1395 way to correctly win in all cases, so we just do the right thing
1396 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1397 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1398 would cause more chaos than dealing with some struct returns being
1402 generic_use_struct_convention (gcc_p
, value_type
)
1404 struct type
*value_type
;
1406 return !((gcc_p
== 1)
1407 && (TYPE_LENGTH (value_type
) == 1
1408 || TYPE_LENGTH (value_type
) == 2
1409 || TYPE_LENGTH (value_type
) == 4
1410 || TYPE_LENGTH (value_type
) == 8));
1413 #ifndef USE_STRUCT_CONVENTION
1414 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1417 /* Some fundamental types (such as long double) are returned on the stack for
1418 certain architectures. This macro should return true for any type besides
1419 struct, union or array that gets returned on the stack. */
1421 #ifndef RETURN_VALUE_ON_STACK
1422 #define RETURN_VALUE_ON_STACK(TYPE) 0
1425 /* Return true if the function specified is using the structure returning
1426 convention on this machine to return arguments, or 0 if it is using
1427 the value returning convention. FUNCTION is the value representing
1428 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1429 is the type returned by the function. GCC_P is nonzero if compiled
1433 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1436 struct type
*value_type
;
1440 register enum type_code code
= TYPE_CODE (value_type
);
1442 if (code
== TYPE_CODE_ERROR
)
1443 error ("Function return type unknown.");
1445 if (code
== TYPE_CODE_STRUCT
1446 || code
== TYPE_CODE_UNION
1447 || code
== TYPE_CODE_ARRAY
1448 || RETURN_VALUE_ON_STACK (value_type
))
1449 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1454 /* Store VAL so it will be returned if a function returns now.
1455 Does not verify that VAL's type matches what the current
1456 function wants to return. */
1459 set_return_value (val
)
1462 struct type
*type
= check_typedef (VALUE_TYPE (val
));
1463 register enum type_code code
= TYPE_CODE (type
);
1465 if (code
== TYPE_CODE_ERROR
)
1466 error ("Function return type unknown.");
1468 if ( code
== TYPE_CODE_STRUCT
1469 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1470 error ("GDB does not support specifying a struct or union return value.");
1472 STORE_RETURN_VALUE (type
, VALUE_CONTENTS (val
));
1476 _initialize_values ()
1478 add_cmd ("convenience", no_class
, show_convenience
,
1479 "Debugger convenience (\"$foo\") variables.\n\
1480 These variables are created when you assign them values;\n\
1481 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1482 A few convenience variables are given values automatically:\n\
1483 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1484 \"$__\" holds the contents of the last address examined with \"x\".",
1487 add_cmd ("values", no_class
, show_values
,
1488 "Elements of value history around item number IDX (or last ten).",