1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
3 1996, 1997, 1998, 1999, 2000
4 Free 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 2 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, write to the Free Software
20 Foundation, Inc., 59 Temple Place - Suite 330,
21 Boston, MA 02111-1307, USA. */
24 #include "gdb_string.h"
36 /* Prototypes for exported functions. */
38 void _initialize_values (void);
40 /* Prototypes for local functions. */
42 static value_ptr
value_headof (value_ptr
, struct type
*, struct type
*);
44 static void show_values (char *, int);
46 static void show_convenience (char *, int);
49 /* The value-history records all the values printed
50 by print commands during this session. Each chunk
51 records 60 consecutive values. The first chunk on
52 the chain records the most recent values.
53 The total number of values is in value_history_count. */
55 #define VALUE_HISTORY_CHUNK 60
57 struct value_history_chunk
59 struct value_history_chunk
*next
;
60 value_ptr values
[VALUE_HISTORY_CHUNK
];
63 /* Chain of chunks now in use. */
65 static struct value_history_chunk
*value_history_chain
;
67 static int value_history_count
; /* Abs number of last entry stored */
69 /* List of all value objects currently allocated
70 (except for those released by calls to release_value)
71 This is so they can be freed after each command. */
73 static value_ptr all_values
;
75 /* Allocate a value that has the correct length for type TYPE. */
78 allocate_value (struct type
*type
)
80 register value_ptr val
;
81 struct type
*atype
= check_typedef (type
);
83 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (atype
));
84 VALUE_NEXT (val
) = all_values
;
86 VALUE_TYPE (val
) = type
;
87 VALUE_ENCLOSING_TYPE (val
) = type
;
88 VALUE_LVAL (val
) = not_lval
;
89 VALUE_ADDRESS (val
) = 0;
90 VALUE_FRAME (val
) = 0;
91 VALUE_OFFSET (val
) = 0;
92 VALUE_BITPOS (val
) = 0;
93 VALUE_BITSIZE (val
) = 0;
94 VALUE_REGNO (val
) = -1;
96 VALUE_OPTIMIZED_OUT (val
) = 0;
97 VALUE_BFD_SECTION (val
) = NULL
;
98 VALUE_EMBEDDED_OFFSET (val
) = 0;
99 VALUE_POINTED_TO_OFFSET (val
) = 0;
104 /* Allocate a value that has the correct length
105 for COUNT repetitions type TYPE. */
108 allocate_repeat_value (struct type
*type
, int count
)
110 int low_bound
= current_language
->string_lower_bound
; /* ??? */
111 /* FIXME-type-allocation: need a way to free this type when we are
113 struct type
*range_type
114 = create_range_type ((struct type
*) NULL
, builtin_type_int
,
115 low_bound
, count
+ low_bound
- 1);
116 /* FIXME-type-allocation: need a way to free this type when we are
118 return allocate_value (create_array_type ((struct type
*) NULL
,
122 /* Return a mark in the value chain. All values allocated after the
123 mark is obtained (except for those released) are subject to being freed
124 if a subsequent value_free_to_mark is passed the mark. */
131 /* Free all values allocated since MARK was obtained by value_mark
132 (except for those released). */
134 value_free_to_mark (value_ptr mark
)
138 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
140 next
= VALUE_NEXT (val
);
146 /* Free all the values that have been allocated (except for those released).
147 Called after each command, successful or not. */
150 free_all_values (void)
152 register value_ptr val
, next
;
154 for (val
= all_values
; val
; val
= next
)
156 next
= VALUE_NEXT (val
);
163 /* Remove VAL from the chain all_values
164 so it will not be freed automatically. */
167 release_value (register value_ptr val
)
169 register value_ptr v
;
171 if (all_values
== val
)
173 all_values
= val
->next
;
177 for (v
= all_values
; v
; v
= v
->next
)
187 /* Release all values up to mark */
189 value_release_to_mark (value_ptr mark
)
193 for (val
= next
= all_values
; next
; next
= VALUE_NEXT (next
))
194 if (VALUE_NEXT (next
) == mark
)
196 all_values
= VALUE_NEXT (next
);
197 VALUE_NEXT (next
) = 0;
204 /* Return a copy of the value ARG.
205 It contains the same contents, for same memory address,
206 but it's a different block of storage. */
209 value_copy (value_ptr arg
)
211 register struct type
*encl_type
= VALUE_ENCLOSING_TYPE (arg
);
212 register value_ptr val
= allocate_value (encl_type
);
213 VALUE_TYPE (val
) = VALUE_TYPE (arg
);
214 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
215 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
216 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
217 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
218 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
219 VALUE_FRAME (val
) = VALUE_FRAME (arg
);
220 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
221 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
222 VALUE_OPTIMIZED_OUT (val
) = VALUE_OPTIMIZED_OUT (arg
);
223 VALUE_EMBEDDED_OFFSET (val
) = VALUE_EMBEDDED_OFFSET (arg
);
224 VALUE_POINTED_TO_OFFSET (val
) = VALUE_POINTED_TO_OFFSET (arg
);
225 VALUE_BFD_SECTION (val
) = VALUE_BFD_SECTION (arg
);
226 val
->modifiable
= arg
->modifiable
;
227 if (!VALUE_LAZY (val
))
229 memcpy (VALUE_CONTENTS_ALL_RAW (val
), VALUE_CONTENTS_ALL_RAW (arg
),
230 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg
)));
236 /* Access to the value history. */
238 /* Record a new value in the value history.
239 Returns the absolute history index of the entry.
240 Result of -1 indicates the value was not saved; otherwise it is the
241 value history index of this new item. */
244 record_latest_value (value_ptr val
)
248 /* We don't want this value to have anything to do with the inferior anymore.
249 In particular, "set $1 = 50" should not affect the variable from which
250 the value was taken, and fast watchpoints should be able to assume that
251 a value on the value history never changes. */
252 if (VALUE_LAZY (val
))
253 value_fetch_lazy (val
);
254 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
255 from. This is a bit dubious, because then *&$1 does not just return $1
256 but the current contents of that location. c'est la vie... */
260 /* Here we treat value_history_count as origin-zero
261 and applying to the value being stored now. */
263 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
266 register struct value_history_chunk
*new
267 = (struct value_history_chunk
*)
268 xmalloc (sizeof (struct value_history_chunk
));
269 memset (new->values
, 0, sizeof new->values
);
270 new->next
= value_history_chain
;
271 value_history_chain
= new;
274 value_history_chain
->values
[i
] = val
;
276 /* Now we regard value_history_count as origin-one
277 and applying to the value just stored. */
279 return ++value_history_count
;
282 /* Return a copy of the value in the history with sequence number NUM. */
285 access_value_history (int num
)
287 register struct value_history_chunk
*chunk
;
289 register int absnum
= num
;
292 absnum
+= value_history_count
;
297 error ("The history is empty.");
299 error ("There is only one value in the history.");
301 error ("History does not go back to $$%d.", -num
);
303 if (absnum
> value_history_count
)
304 error ("History has not yet reached $%d.", absnum
);
308 /* Now absnum is always absolute and origin zero. */
310 chunk
= value_history_chain
;
311 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
315 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
318 /* Clear the value history entirely.
319 Must be done when new symbol tables are loaded,
320 because the type pointers become invalid. */
323 clear_value_history (void)
325 register struct value_history_chunk
*next
;
327 register value_ptr val
;
329 while (value_history_chain
)
331 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
332 if ((val
= value_history_chain
->values
[i
]) != NULL
)
334 next
= value_history_chain
->next
;
335 xfree (value_history_chain
);
336 value_history_chain
= next
;
338 value_history_count
= 0;
342 show_values (char *num_exp
, int from_tty
)
345 register value_ptr val
;
350 /* "info history +" should print from the stored position.
351 "info history <exp>" should print around value number <exp>. */
352 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
353 num
= parse_and_eval_long (num_exp
) - 5;
357 /* "info history" means print the last 10 values. */
358 num
= value_history_count
- 9;
364 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
366 val
= access_value_history (i
);
367 printf_filtered ("$%d = ", i
);
368 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
369 printf_filtered ("\n");
372 /* The next "info history +" should start after what we just printed. */
375 /* Hitting just return after this command should do the same thing as
376 "info history +". If num_exp is null, this is unnecessary, since
377 "info history +" is not useful after "info history". */
378 if (from_tty
&& num_exp
)
385 /* Internal variables. These are variables within the debugger
386 that hold values assigned by debugger commands.
387 The user refers to them with a '$' prefix
388 that does not appear in the variable names stored internally. */
390 static struct internalvar
*internalvars
;
392 /* Look up an internal variable with name NAME. NAME should not
393 normally include a dollar sign.
395 If the specified internal variable does not exist,
396 one is created, with a void value. */
399 lookup_internalvar (char *name
)
401 register struct internalvar
*var
;
403 for (var
= internalvars
; var
; var
= var
->next
)
404 if (STREQ (var
->name
, name
))
407 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
408 var
->name
= concat (name
, NULL
);
409 var
->value
= allocate_value (builtin_type_void
);
410 release_value (var
->value
);
411 var
->next
= internalvars
;
417 value_of_internalvar (struct internalvar
*var
)
419 register value_ptr val
;
421 #ifdef IS_TRAPPED_INTERNALVAR
422 if (IS_TRAPPED_INTERNALVAR (var
->name
))
423 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
426 val
= value_copy (var
->value
);
427 if (VALUE_LAZY (val
))
428 value_fetch_lazy (val
);
429 VALUE_LVAL (val
) = lval_internalvar
;
430 VALUE_INTERNALVAR (val
) = var
;
435 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
436 int bitsize
, value_ptr newval
)
438 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
440 #ifdef IS_TRAPPED_INTERNALVAR
441 if (IS_TRAPPED_INTERNALVAR (var
->name
))
442 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
446 modify_field (addr
, value_as_long (newval
),
449 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
453 set_internalvar (struct internalvar
*var
, value_ptr val
)
457 #ifdef IS_TRAPPED_INTERNALVAR
458 if (IS_TRAPPED_INTERNALVAR (var
->name
))
459 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
462 newval
= value_copy (val
);
463 newval
->modifiable
= 1;
465 /* Force the value to be fetched from the target now, to avoid problems
466 later when this internalvar is referenced and the target is gone or
468 if (VALUE_LAZY (newval
))
469 value_fetch_lazy (newval
);
471 /* Begin code which must not call error(). If var->value points to
472 something free'd, an error() obviously leaves a dangling pointer.
473 But we also get a danling pointer if var->value points to
474 something in the value chain (i.e., before release_value is
475 called), because after the error free_all_values will get called before
479 release_value (newval
);
480 /* End code which must not call error(). */
484 internalvar_name (struct internalvar
*var
)
489 /* Free all internalvars. Done when new symtabs are loaded,
490 because that makes the values invalid. */
493 clear_internalvars (void)
495 register struct internalvar
*var
;
500 internalvars
= var
->next
;
508 show_convenience (char *ignore
, int from_tty
)
510 register struct internalvar
*var
;
513 for (var
= internalvars
; var
; var
= var
->next
)
515 #ifdef IS_TRAPPED_INTERNALVAR
516 if (IS_TRAPPED_INTERNALVAR (var
->name
))
523 printf_filtered ("$%s = ", var
->name
);
524 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
525 printf_filtered ("\n");
528 printf_unfiltered ("No debugger convenience variables now defined.\n\
529 Convenience variables have names starting with \"$\";\n\
530 use \"set\" as in \"set $foo = 5\" to define them.\n");
533 /* Extract a value as a C number (either long or double).
534 Knows how to convert fixed values to double, or
535 floating values to long.
536 Does not deallocate the value. */
539 value_as_long (register value_ptr val
)
541 /* This coerces arrays and functions, which is necessary (e.g.
542 in disassemble_command). It also dereferences references, which
543 I suspect is the most logical thing to do. */
545 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
549 value_as_double (register value_ptr val
)
554 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
556 error ("Invalid floating value found in program.");
559 /* Extract a value as a C pointer. Does not deallocate the value.
560 Note that val's type may not actually be a pointer; value_as_long
561 handles all the cases. */
563 value_as_pointer (value_ptr val
)
565 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
566 whether we want this to be true eventually. */
568 /* ADDR_BITS_REMOVE is wrong if we are being called for a
569 non-address (e.g. argument to "signal", "info break", etc.), or
570 for pointers to char, in which the low bits *are* significant. */
571 return ADDR_BITS_REMOVE (value_as_long (val
));
574 /* In converting VAL to an address (CORE_ADDR), any small integers
575 are first cast to a generic pointer. The function unpack_long
576 will then correctly convert that pointer into a canonical address
577 (using POINTER_TO_ADDRESS).
579 Without the cast, the MIPS gets: 0xa0000000 -> (unsigned int)
580 0xa0000000 -> (LONGEST) 0x00000000a0000000
582 With the cast, the MIPS gets: 0xa0000000 -> (unsigned int)
583 0xa0000000 -> (void*) 0xa0000000 -> (LONGEST) 0xffffffffa0000000.
585 If the user specifies an integer that is larger than the target
586 pointer type, it is assumed that it was intentional and the value
587 is converted directly into an ADDRESS. This ensures that no
588 information is discarded.
590 NOTE: The cast operation may eventualy be converted into a TARGET
591 method (see POINTER_TO_ADDRESS() and ADDRESS_TO_POINTER()) so
592 that the TARGET ISA/ABI can apply an arbitrary conversion.
594 NOTE: In pure harvard architectures function and data pointers
595 can be different and may require different integer to pointer
597 if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_INT
598 && (TYPE_LENGTH (VALUE_TYPE (val
))
599 <= TYPE_LENGTH (builtin_type_void_data_ptr
)))
601 val
= value_cast (builtin_type_void_data_ptr
, val
);
603 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
607 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
608 as a long, or as a double, assuming the raw data is described
609 by type TYPE. Knows how to convert different sizes of values
610 and can convert between fixed and floating point. We don't assume
611 any alignment for the raw data. Return value is in host byte order.
613 If you want functions and arrays to be coerced to pointers, and
614 references to be dereferenced, call value_as_long() instead.
616 C++: It is assumed that the front-end has taken care of
617 all matters concerning pointers to members. A pointer
618 to member which reaches here is considered to be equivalent
619 to an INT (or some size). After all, it is only an offset. */
622 unpack_long (struct type
*type
, char *valaddr
)
624 register enum type_code code
= TYPE_CODE (type
);
625 register int len
= TYPE_LENGTH (type
);
626 register int nosign
= TYPE_UNSIGNED (type
);
628 if (current_language
->la_language
== language_scm
629 && is_scmvalue_type (type
))
630 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
634 case TYPE_CODE_TYPEDEF
:
635 return unpack_long (check_typedef (type
), valaddr
);
640 case TYPE_CODE_RANGE
:
642 return extract_unsigned_integer (valaddr
, len
);
644 return extract_signed_integer (valaddr
, len
);
647 return extract_floating (valaddr
, len
);
651 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
652 whether we want this to be true eventually. */
653 return extract_typed_address (valaddr
, type
);
655 case TYPE_CODE_MEMBER
:
656 error ("not implemented: member types in unpack_long");
659 error ("Value can't be converted to integer.");
661 return 0; /* Placate lint. */
664 /* Return a double value from the specified type and address.
665 INVP points to an int which is set to 0 for valid value,
666 1 for invalid value (bad float format). In either case,
667 the returned double is OK to use. Argument is in target
668 format, result is in host format. */
671 unpack_double (struct type
*type
, char *valaddr
, int *invp
)
677 *invp
= 0; /* Assume valid. */
678 CHECK_TYPEDEF (type
);
679 code
= TYPE_CODE (type
);
680 len
= TYPE_LENGTH (type
);
681 nosign
= TYPE_UNSIGNED (type
);
682 if (code
== TYPE_CODE_FLT
)
685 if (INVALID_FLOAT (valaddr
, len
))
688 return 1.234567891011121314;
691 return extract_floating (valaddr
, len
);
695 /* Unsigned -- be sure we compensate for signed LONGEST. */
696 return (ULONGEST
) unpack_long (type
, valaddr
);
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 (struct type
*type
, char *valaddr
)
721 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
722 whether we want this to be true eventually. */
723 return unpack_long (type
, valaddr
);
727 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
730 value_static_field (struct type
*type
, int fieldno
)
734 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
736 addr
= TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
);
741 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
742 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_NAMESPACE
, 0, NULL
);
745 /* With some compilers, e.g. HP aCC, static data members are reported
746 as non-debuggable symbols */
747 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
752 addr
= SYMBOL_VALUE_ADDRESS (msym
);
753 sect
= SYMBOL_BFD_SECTION (msym
);
758 /* Anything static that isn't a constant, has an address */
759 if (SYMBOL_CLASS (sym
) != LOC_CONST
)
761 addr
= SYMBOL_VALUE_ADDRESS (sym
);
762 sect
= SYMBOL_BFD_SECTION (sym
);
764 /* However, static const's do not, the value is already known. */
767 return value_from_longest (TYPE_FIELD_TYPE (type
, fieldno
), SYMBOL_VALUE (sym
));
770 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
), addr
);
772 return value_at (TYPE_FIELD_TYPE (type
, fieldno
), addr
, sect
);
775 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
776 You have to be careful here, since the size of the data area for the value
777 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
778 than the old enclosing type, you have to allocate more space for the data.
779 The return value is a pointer to the new version of this value structure. */
782 value_change_enclosing_type (value_ptr val
, struct type
*new_encl_type
)
784 if (TYPE_LENGTH (new_encl_type
) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val
)))
786 VALUE_ENCLOSING_TYPE (val
) = new_encl_type
;
792 register value_ptr prev
;
794 new_val
= (value_ptr
) xrealloc (val
, sizeof (struct value
) + TYPE_LENGTH (new_encl_type
));
796 /* We have to make sure this ends up in the same place in the value
797 chain as the original copy, so it's clean-up behavior is the same.
798 If the value has been released, this is a waste of time, but there
799 is no way to tell that in advance, so... */
801 if (val
!= all_values
)
803 for (prev
= all_values
; prev
!= NULL
; prev
= prev
->next
)
805 if (prev
->next
== val
)
807 prev
->next
= new_val
;
817 /* Given a value ARG1 (offset by OFFSET bytes)
818 of a struct or union type ARG_TYPE,
819 extract and return the value of one of its (non-static) fields.
820 FIELDNO says which field. */
823 value_primitive_field (register value_ptr arg1
, int offset
,
824 register int fieldno
, register struct type
*arg_type
)
826 register value_ptr v
;
827 register struct type
*type
;
829 CHECK_TYPEDEF (arg_type
);
830 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
832 /* Handle packed fields */
834 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
836 v
= value_from_longest (type
,
837 unpack_field_as_long (arg_type
,
838 VALUE_CONTENTS (arg1
)
841 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
842 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
843 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
844 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
846 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
848 /* This field is actually a base subobject, so preserve the
849 entire object's contents for later references to virtual
851 v
= allocate_value (VALUE_ENCLOSING_TYPE (arg1
));
852 VALUE_TYPE (v
) = type
;
853 if (VALUE_LAZY (arg1
))
856 memcpy (VALUE_CONTENTS_ALL_RAW (v
), VALUE_CONTENTS_ALL_RAW (arg1
),
857 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1
)));
858 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
);
859 VALUE_EMBEDDED_OFFSET (v
)
861 VALUE_EMBEDDED_OFFSET (arg1
) +
862 TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
866 /* Plain old data member */
867 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
868 v
= allocate_value (type
);
869 if (VALUE_LAZY (arg1
))
872 memcpy (VALUE_CONTENTS_RAW (v
),
873 VALUE_CONTENTS_RAW (arg1
) + offset
,
875 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
;
877 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
878 if (VALUE_LVAL (arg1
) == lval_internalvar
)
879 VALUE_LVAL (v
) = lval_internalvar_component
;
880 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
881 VALUE_REGNO (v
) = VALUE_REGNO (arg1
);
882 /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
883 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
887 /* Given a value ARG1 of a struct or union type,
888 extract and return the value of one of its (non-static) fields.
889 FIELDNO says which field. */
892 value_field (register value_ptr arg1
, register int fieldno
)
894 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
897 /* Return a non-virtual function as a value.
898 F is the list of member functions which contains the desired method.
899 J is an index into F which provides the desired method. */
902 value_fn_field (value_ptr
*arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
905 register value_ptr v
;
906 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
909 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
910 0, VAR_NAMESPACE
, 0, NULL
);
914 error ("Internal error: could not find physical method named %s",
915 TYPE_FN_FIELD_PHYSNAME (f, j));
918 v
= allocate_value (ftype
);
919 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
920 VALUE_TYPE (v
) = ftype
;
924 if (type
!= VALUE_TYPE (*arg1p
))
925 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
926 value_addr (*arg1p
)));
928 /* Move the `this' pointer according to the offset.
929 VALUE_OFFSET (*arg1p) += offset;
936 /* ARG is a pointer to an object we know to be at least
937 a DTYPE. BTYPE is the most derived basetype that has
938 already been searched (and need not be searched again).
939 After looking at the vtables between BTYPE and DTYPE,
940 return the most derived type we find. The caller must
941 be satisfied when the return value == DTYPE.
943 FIXME-tiemann: should work with dossier entries as well.
944 NOTICE - djb: I see no good reason at all to keep this function now that
945 we have RTTI support. It's used in literally one place, and it's
946 hard to keep this function up to date when it's purpose is served
947 by value_rtti_type efficiently.
948 Consider it gone for 5.1. */
951 value_headof (value_ptr in_arg
, struct type
*btype
, struct type
*dtype
)
953 /* First collect the vtables we must look at for this object. */
956 char *demangled_name
;
957 struct minimal_symbol
*msymbol
;
959 btype
= TYPE_VPTR_BASETYPE (dtype
);
960 CHECK_TYPEDEF (btype
);
963 arg
= value_cast (lookup_pointer_type (btype
), arg
);
964 if (TYPE_CODE (VALUE_TYPE (arg
)) == TYPE_CODE_REF
)
967 * Copy the value, but change the type from (T&) to (T*).
968 * We keep the same location information, which is efficient,
969 * and allows &(&X) to get the location containing the reference.
971 arg
= value_copy (arg
);
972 VALUE_TYPE (arg
) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg
)));
974 if (VALUE_ADDRESS(value_field (value_ind(arg
), TYPE_VPTR_FIELDNO (btype
)))==0)
977 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
978 /* Turn vtable into typeinfo function */
979 VALUE_OFFSET(vtbl
)+=4;
981 msymbol
= lookup_minimal_symbol_by_pc ( value_as_pointer(value_ind(vtbl
)) );
983 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
)
985 /* If we expected to find a vtable, but did not, let the user
986 know that we aren't happy, but don't throw an error.
987 FIXME: there has to be a better way to do this. */
988 struct type
*error_type
= (struct type
*) xmalloc (sizeof (struct type
));
989 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
990 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
991 VALUE_TYPE (in_arg
) = error_type
;
994 demangled_name
= cplus_demangle(demangled_name
,DMGL_ANSI
);
995 *(strchr (demangled_name
, ' ')) = '\0';
997 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
999 error ("could not find type declaration for `%s'", demangled_name
);
1002 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1006 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1007 function tables, probe ARG's tables (including the vtables
1008 of its baseclasses) to figure out the most derived type that ARG
1009 could actually be a pointer to. */
1012 value_from_vtable_info (value_ptr arg
, struct type
*type
)
1014 /* Take care of preliminaries. */
1015 if (TYPE_VPTR_FIELDNO (type
) < 0)
1016 fill_in_vptr_fieldno (type
);
1017 if (TYPE_VPTR_FIELDNO (type
) < 0)
1020 return value_headof (arg
, 0, type
);
1023 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1024 pointer which is for the base class whose type is BASECLASS. */
1027 vb_match (struct type
*type
, int index
, struct type
*basetype
)
1029 struct type
*fieldtype
;
1030 char *name
= TYPE_FIELD_NAME (type
, index
);
1031 char *field_class_name
= NULL
;
1035 /* gcc 2.4 uses _vb$. */
1036 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
1037 field_class_name
= name
+ 4;
1038 /* gcc 2.5 will use __vb_. */
1039 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1040 field_class_name
= name
+ 5;
1042 if (field_class_name
== NULL
)
1043 /* This field is not a virtual base class pointer. */
1046 /* It's a virtual baseclass pointer, now we just need to find out whether
1047 it is for this baseclass. */
1048 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1049 if (fieldtype
== NULL
1050 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1051 /* "Can't happen". */
1054 /* What we check for is that either the types are equal (needed for
1055 nameless types) or have the same name. This is ugly, and a more
1056 elegant solution should be devised (which would probably just push
1057 the ugliness into symbol reading unless we change the stabs format). */
1058 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1061 if (TYPE_NAME (basetype
) != NULL
1062 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1063 && STREQ (TYPE_NAME (basetype
),
1064 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1069 /* Compute the offset of the baseclass which is
1070 the INDEXth baseclass of class TYPE,
1071 for value at VALADDR (in host) at ADDRESS (in target).
1072 The result is the offset of the baseclass value relative
1073 to (the address of)(ARG) + OFFSET.
1075 -1 is returned on error. */
1078 baseclass_offset (struct type
*type
, int index
, char *valaddr
,
1081 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1083 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1085 /* Must hunt for the pointer to this virtual baseclass. */
1086 register int i
, len
= TYPE_NFIELDS (type
);
1087 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1089 /* First look for the virtual baseclass pointer
1091 for (i
= n_baseclasses
; i
< len
; i
++)
1093 if (vb_match (type
, i
, basetype
))
1096 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1097 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1099 return addr
- (LONGEST
) address
;
1102 /* Not in the fields, so try looking through the baseclasses. */
1103 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
1106 baseclass_offset (type
, i
, valaddr
, address
);
1114 /* Baseclass is easily computed. */
1115 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1118 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1121 Extracting bits depends on endianness of the machine. Compute the
1122 number of least significant bits to discard. For big endian machines,
1123 we compute the total number of bits in the anonymous object, subtract
1124 off the bit count from the MSB of the object to the MSB of the
1125 bitfield, then the size of the bitfield, which leaves the LSB discard
1126 count. For little endian machines, the discard count is simply the
1127 number of bits from the LSB of the anonymous object to the LSB of the
1130 If the field is signed, we also do sign extension. */
1133 unpack_field_as_long (struct type
*type
, char *valaddr
, int fieldno
)
1137 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1138 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1140 struct type
*field_type
;
1142 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1143 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1144 CHECK_TYPEDEF (field_type
);
1146 /* Extract bits. See comment above. */
1148 if (BITS_BIG_ENDIAN
)
1149 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1151 lsbcount
= (bitpos
% 8);
1154 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1155 If the field is signed, and is negative, then sign extend. */
1157 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1159 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1161 if (!TYPE_UNSIGNED (field_type
))
1163 if (val
& (valmask
^ (valmask
>> 1)))
1172 /* Modify the value of a bitfield. ADDR points to a block of memory in
1173 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1174 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1175 indicate which bits (in target bit order) comprise the bitfield. */
1178 modify_field (char *addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1182 /* If a negative fieldval fits in the field in question, chop
1183 off the sign extension bits. */
1184 if (bitsize
< (8 * (int) sizeof (fieldval
))
1185 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1186 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1188 /* Warn if value is too big to fit in the field in question. */
1189 if (bitsize
< (8 * (int) sizeof (fieldval
))
1190 && 0 != (fieldval
& ~((1 << bitsize
) - 1)))
1192 /* FIXME: would like to include fieldval in the message, but
1193 we don't have a sprintf_longest. */
1194 warning ("Value does not fit in %d bits.", bitsize
);
1196 /* Truncate it, otherwise adjoining fields may be corrupted. */
1197 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1200 oword
= extract_signed_integer (addr
, sizeof oword
);
1202 /* Shifting for bit field depends on endianness of the target machine. */
1203 if (BITS_BIG_ENDIAN
)
1204 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1206 /* Mask out old value, while avoiding shifts >= size of oword */
1207 if (bitsize
< 8 * (int) sizeof (oword
))
1208 oword
&= ~(((((ULONGEST
) 1) << bitsize
) - 1) << bitpos
);
1210 oword
&= ~((~(ULONGEST
) 0) << bitpos
);
1211 oword
|= fieldval
<< bitpos
;
1213 store_signed_integer (addr
, sizeof oword
, oword
);
1216 /* Convert C numbers into newly allocated values */
1219 value_from_longest (struct type
*type
, register LONGEST num
)
1221 register value_ptr val
= allocate_value (type
);
1222 register enum type_code code
;
1225 code
= TYPE_CODE (type
);
1226 len
= TYPE_LENGTH (type
);
1230 case TYPE_CODE_TYPEDEF
:
1231 type
= check_typedef (type
);
1234 case TYPE_CODE_CHAR
:
1235 case TYPE_CODE_ENUM
:
1236 case TYPE_CODE_BOOL
:
1237 case TYPE_CODE_RANGE
:
1238 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1243 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, (CORE_ADDR
) num
);
1247 error ("Unexpected type (%d) encountered for integer constant.", code
);
1253 /* Create a value representing a pointer of type TYPE to the address
1256 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
1258 value_ptr val
= allocate_value (type
);
1259 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, addr
);
1264 /* Create a value for a string constant to be stored locally
1265 (not in the inferior's memory space, but in GDB memory).
1266 This is analogous to value_from_longest, which also does not
1267 use inferior memory. String shall NOT contain embedded nulls. */
1270 value_from_string (char *ptr
)
1273 int len
= strlen (ptr
);
1274 int lowbound
= current_language
->string_lower_bound
;
1275 struct type
*rangetype
=
1276 create_range_type ((struct type
*) NULL
,
1278 lowbound
, len
+ lowbound
- 1);
1279 struct type
*stringtype
=
1280 create_array_type ((struct type
*) NULL
,
1281 *current_language
->string_char_type
,
1284 val
= allocate_value (stringtype
);
1285 memcpy (VALUE_CONTENTS_RAW (val
), ptr
, len
);
1290 value_from_double (struct type
*type
, DOUBLEST num
)
1292 register value_ptr val
= allocate_value (type
);
1293 struct type
*base_type
= check_typedef (type
);
1294 register enum type_code code
= TYPE_CODE (base_type
);
1295 register int len
= TYPE_LENGTH (base_type
);
1297 if (code
== TYPE_CODE_FLT
)
1299 store_floating (VALUE_CONTENTS_RAW (val
), len
, num
);
1302 error ("Unexpected type encountered for floating constant.");
1307 /* Deal with the value that is "about to be returned". */
1309 /* Return the value that a function returning now
1310 would be returning to its caller, assuming its type is VALTYPE.
1311 RETBUF is where we look for what ought to be the contents
1312 of the registers (in raw form). This is because it is often
1313 desirable to restore old values to those registers
1314 after saving the contents of interest, and then call
1315 this function using the saved values.
1316 struct_return is non-zero when the function in question is
1317 using the structure return conventions on the machine in question;
1318 0 when it is using the value returning conventions (this often
1319 means returning pointer to where structure is vs. returning value). */
1323 value_being_returned (struct type
*valtype
, char *retbuf
, int struct_return
)
1325 register value_ptr val
;
1328 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1329 if (EXTRACT_STRUCT_VALUE_ADDRESS_P ())
1332 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1334 error ("Function return value unknown");
1335 return value_at (valtype
, addr
, NULL
);
1338 val
= allocate_value (valtype
);
1339 CHECK_TYPEDEF (valtype
);
1340 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1345 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1346 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1347 and TYPE is the type (which is known to be struct, union or array).
1349 On most machines, the struct convention is used unless we are
1350 using gcc and the type is of a special size. */
1351 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1352 native compiler. GCC 2.3.3 was the last release that did it the
1353 old way. Since gcc2_compiled was not changed, we have no
1354 way to correctly win in all cases, so we just do the right thing
1355 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1356 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1357 would cause more chaos than dealing with some struct returns being
1361 generic_use_struct_convention (int gcc_p
, struct type
*value_type
)
1363 return !((gcc_p
== 1)
1364 && (TYPE_LENGTH (value_type
) == 1
1365 || TYPE_LENGTH (value_type
) == 2
1366 || TYPE_LENGTH (value_type
) == 4
1367 || TYPE_LENGTH (value_type
) == 8));
1370 #ifndef USE_STRUCT_CONVENTION
1371 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1375 /* Return true if the function specified is using the structure returning
1376 convention on this machine to return arguments, or 0 if it is using
1377 the value returning convention. FUNCTION is the value representing
1378 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1379 is the type returned by the function. GCC_P is nonzero if compiled
1384 using_struct_return (value_ptr function
, CORE_ADDR funcaddr
,
1385 struct type
*value_type
, int gcc_p
)
1387 register enum type_code code
= TYPE_CODE (value_type
);
1389 if (code
== TYPE_CODE_ERROR
)
1390 error ("Function return type unknown.");
1392 if (code
== TYPE_CODE_STRUCT
1393 || code
== TYPE_CODE_UNION
1394 || code
== TYPE_CODE_ARRAY
1395 || RETURN_VALUE_ON_STACK (value_type
))
1396 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1401 /* Store VAL so it will be returned if a function returns now.
1402 Does not verify that VAL's type matches what the current
1403 function wants to return. */
1406 set_return_value (value_ptr val
)
1408 struct type
*type
= check_typedef (VALUE_TYPE (val
));
1409 register enum type_code code
= TYPE_CODE (type
);
1411 if (code
== TYPE_CODE_ERROR
)
1412 error ("Function return type unknown.");
1414 if (code
== TYPE_CODE_STRUCT
1415 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1416 error ("GDB does not support specifying a struct or union return value.");
1418 STORE_RETURN_VALUE (type
, VALUE_CONTENTS (val
));
1422 _initialize_values (void)
1424 add_cmd ("convenience", no_class
, show_convenience
,
1425 "Debugger convenience (\"$foo\") variables.\n\
1426 These variables are created when you assign them values;\n\
1427 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1428 A few convenience variables are given values automatically:\n\
1429 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1430 \"$__\" holds the contents of the last address examined with \"x\".",
1433 add_cmd ("values", no_class
, show_values
,
1434 "Elements of value history around item number IDX (or last ten).",