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"
37 /* Prototypes for exported functions. */
39 void _initialize_values (void);
41 /* Prototypes for local functions. */
43 static value_ptr
value_headof (value_ptr
, struct type
*, struct type
*);
45 static void show_values (char *, int);
47 static void show_convenience (char *, int);
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. */
79 allocate_value (struct type
*type
)
81 register value_ptr val
;
82 struct type
*atype
= check_typedef (type
);
84 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (atype
));
85 VALUE_NEXT (val
) = all_values
;
87 VALUE_TYPE (val
) = type
;
88 VALUE_ENCLOSING_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
;
99 VALUE_EMBEDDED_OFFSET (val
) = 0;
100 VALUE_POINTED_TO_OFFSET (val
) = 0;
105 /* Allocate a value that has the correct length
106 for COUNT repetitions type TYPE. */
109 allocate_repeat_value (struct type
*type
, int 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 (value_ptr mark
)
139 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
141 next
= VALUE_NEXT (val
);
147 /* Free all the values that have been allocated (except for those released).
148 Called after each command, successful or not. */
151 free_all_values (void)
153 register value_ptr val
, next
;
155 for (val
= all_values
; val
; val
= next
)
157 next
= VALUE_NEXT (val
);
164 /* Remove VAL from the chain all_values
165 so it will not be freed automatically. */
168 release_value (register value_ptr val
)
170 register value_ptr v
;
172 if (all_values
== val
)
174 all_values
= val
->next
;
178 for (v
= all_values
; v
; v
= v
->next
)
188 /* Release all values up to mark */
190 value_release_to_mark (value_ptr mark
)
194 for (val
= next
= all_values
; next
; next
= VALUE_NEXT (next
))
195 if (VALUE_NEXT (next
) == mark
)
197 all_values
= VALUE_NEXT (next
);
198 VALUE_NEXT (next
) = 0;
205 /* Return a copy of the value ARG.
206 It contains the same contents, for same memory address,
207 but it's a different block of storage. */
210 value_copy (value_ptr arg
)
212 register struct type
*encl_type
= VALUE_ENCLOSING_TYPE (arg
);
213 register value_ptr val
= allocate_value (encl_type
);
214 VALUE_TYPE (val
) = VALUE_TYPE (arg
);
215 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
216 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
217 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
218 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
219 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
220 VALUE_FRAME (val
) = VALUE_FRAME (arg
);
221 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
222 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
223 VALUE_OPTIMIZED_OUT (val
) = VALUE_OPTIMIZED_OUT (arg
);
224 VALUE_EMBEDDED_OFFSET (val
) = VALUE_EMBEDDED_OFFSET (arg
);
225 VALUE_POINTED_TO_OFFSET (val
) = VALUE_POINTED_TO_OFFSET (arg
);
226 VALUE_BFD_SECTION (val
) = VALUE_BFD_SECTION (arg
);
227 val
->modifiable
= arg
->modifiable
;
228 if (!VALUE_LAZY (val
))
230 memcpy (VALUE_CONTENTS_ALL_RAW (val
), VALUE_CONTENTS_ALL_RAW (arg
),
231 TYPE_LENGTH (VALUE_ENCLOSING_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 (value_ptr val
)
249 /* We don't want this value to have anything to do with the inferior anymore.
250 In particular, "set $1 = 50" should not affect the variable from which
251 the value was taken, and fast watchpoints should be able to assume that
252 a value on the value history never changes. */
253 if (VALUE_LAZY (val
))
254 value_fetch_lazy (val
);
255 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
256 from. This is a bit dubious, because then *&$1 does not just return $1
257 but the current contents of that location. c'est la vie... */
261 /* Here we treat value_history_count as origin-zero
262 and applying to the value being stored now. */
264 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
267 register struct value_history_chunk
*new
268 = (struct value_history_chunk
*)
269 xmalloc (sizeof (struct value_history_chunk
));
270 memset (new->values
, 0, sizeof new->values
);
271 new->next
= value_history_chain
;
272 value_history_chain
= new;
275 value_history_chain
->values
[i
] = val
;
277 /* Now we regard value_history_count as origin-one
278 and applying to the value just stored. */
280 return ++value_history_count
;
283 /* Return a copy of the value in the history with sequence number NUM. */
286 access_value_history (int num
)
288 register struct value_history_chunk
*chunk
;
290 register int absnum
= num
;
293 absnum
+= value_history_count
;
298 error ("The history is empty.");
300 error ("There is only one value in the history.");
302 error ("History does not go back to $$%d.", -num
);
304 if (absnum
> value_history_count
)
305 error ("History has not yet reached $%d.", absnum
);
309 /* Now absnum is always absolute and origin zero. */
311 chunk
= value_history_chain
;
312 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
316 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
319 /* Clear the value history entirely.
320 Must be done when new symbol tables are loaded,
321 because the type pointers become invalid. */
324 clear_value_history (void)
326 register struct value_history_chunk
*next
;
328 register value_ptr val
;
330 while (value_history_chain
)
332 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
333 if ((val
= value_history_chain
->values
[i
]) != NULL
)
335 next
= value_history_chain
->next
;
336 xfree (value_history_chain
);
337 value_history_chain
= next
;
339 value_history_count
= 0;
343 show_values (char *num_exp
, int from_tty
)
346 register value_ptr val
;
351 /* "info history +" should print from the stored position.
352 "info history <exp>" should print around value number <exp>. */
353 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
354 num
= parse_and_eval_long (num_exp
) - 5;
358 /* "info history" means print the last 10 values. */
359 num
= value_history_count
- 9;
365 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
367 val
= access_value_history (i
);
368 printf_filtered ("$%d = ", i
);
369 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
370 printf_filtered ("\n");
373 /* The next "info history +" should start after what we just printed. */
376 /* Hitting just return after this command should do the same thing as
377 "info history +". If num_exp is null, this is unnecessary, since
378 "info history +" is not useful after "info history". */
379 if (from_tty
&& num_exp
)
386 /* Internal variables. These are variables within the debugger
387 that hold values assigned by debugger commands.
388 The user refers to them with a '$' prefix
389 that does not appear in the variable names stored internally. */
391 static struct internalvar
*internalvars
;
393 /* Look up an internal variable with name NAME. NAME should not
394 normally include a dollar sign.
396 If the specified internal variable does not exist,
397 one is created, with a void value. */
400 lookup_internalvar (char *name
)
402 register struct internalvar
*var
;
404 for (var
= internalvars
; var
; var
= var
->next
)
405 if (STREQ (var
->name
, name
))
408 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
409 var
->name
= concat (name
, NULL
);
410 var
->value
= allocate_value (builtin_type_void
);
411 release_value (var
->value
);
412 var
->next
= internalvars
;
418 value_of_internalvar (struct internalvar
*var
)
420 register value_ptr val
;
422 #ifdef IS_TRAPPED_INTERNALVAR
423 if (IS_TRAPPED_INTERNALVAR (var
->name
))
424 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
427 val
= value_copy (var
->value
);
428 if (VALUE_LAZY (val
))
429 value_fetch_lazy (val
);
430 VALUE_LVAL (val
) = lval_internalvar
;
431 VALUE_INTERNALVAR (val
) = var
;
436 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
437 int bitsize
, value_ptr newval
)
439 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
441 #ifdef IS_TRAPPED_INTERNALVAR
442 if (IS_TRAPPED_INTERNALVAR (var
->name
))
443 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
447 modify_field (addr
, value_as_long (newval
),
450 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
454 set_internalvar (struct internalvar
*var
, value_ptr val
)
458 #ifdef IS_TRAPPED_INTERNALVAR
459 if (IS_TRAPPED_INTERNALVAR (var
->name
))
460 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
463 newval
= value_copy (val
);
464 newval
->modifiable
= 1;
466 /* Force the value to be fetched from the target now, to avoid problems
467 later when this internalvar is referenced and the target is gone or
469 if (VALUE_LAZY (newval
))
470 value_fetch_lazy (newval
);
472 /* Begin code which must not call error(). If var->value points to
473 something free'd, an error() obviously leaves a dangling pointer.
474 But we also get a danling pointer if var->value points to
475 something in the value chain (i.e., before release_value is
476 called), because after the error free_all_values will get called before
480 release_value (newval
);
481 /* End code which must not call error(). */
485 internalvar_name (struct internalvar
*var
)
490 /* Free all internalvars. Done when new symtabs are loaded,
491 because that makes the values invalid. */
494 clear_internalvars (void)
496 register struct internalvar
*var
;
501 internalvars
= var
->next
;
509 show_convenience (char *ignore
, int from_tty
)
511 register struct internalvar
*var
;
514 for (var
= internalvars
; var
; var
= var
->next
)
516 #ifdef IS_TRAPPED_INTERNALVAR
517 if (IS_TRAPPED_INTERNALVAR (var
->name
))
524 printf_filtered ("$%s = ", var
->name
);
525 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
526 printf_filtered ("\n");
529 printf_unfiltered ("No debugger convenience variables now defined.\n\
530 Convenience variables have names starting with \"$\";\n\
531 use \"set\" as in \"set $foo = 5\" to define them.\n");
534 /* Extract a value as a C number (either long or double).
535 Knows how to convert fixed values to double, or
536 floating values to long.
537 Does not deallocate the value. */
540 value_as_long (register value_ptr val
)
542 /* This coerces arrays and functions, which is necessary (e.g.
543 in disassemble_command). It also dereferences references, which
544 I suspect is the most logical thing to do. */
546 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
550 value_as_double (register value_ptr val
)
555 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
557 error ("Invalid floating value found in program.");
560 /* Extract a value as a C pointer. Does not deallocate the value.
561 Note that val's type may not actually be a pointer; value_as_long
562 handles all the cases. */
564 value_as_pointer (value_ptr val
)
566 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
567 whether we want this to be true eventually. */
569 /* ADDR_BITS_REMOVE is wrong if we are being called for a
570 non-address (e.g. argument to "signal", "info break", etc.), or
571 for pointers to char, in which the low bits *are* significant. */
572 return ADDR_BITS_REMOVE (value_as_long (val
));
575 /* In converting VAL to an address (CORE_ADDR), any small integers
576 are first cast to a generic pointer. The function unpack_long
577 will then correctly convert that pointer into a canonical address
578 (using POINTER_TO_ADDRESS).
580 Without the cast, the MIPS gets: 0xa0000000 -> (unsigned int)
581 0xa0000000 -> (LONGEST) 0x00000000a0000000
583 With the cast, the MIPS gets: 0xa0000000 -> (unsigned int)
584 0xa0000000 -> (void*) 0xa0000000 -> (LONGEST) 0xffffffffa0000000.
586 If the user specifies an integer that is larger than the target
587 pointer type, it is assumed that it was intentional and the value
588 is converted directly into an ADDRESS. This ensures that no
589 information is discarded.
591 NOTE: The cast operation may eventualy be converted into a TARGET
592 method (see POINTER_TO_ADDRESS() and ADDRESS_TO_POINTER()) so
593 that the TARGET ISA/ABI can apply an arbitrary conversion.
595 NOTE: In pure harvard architectures function and data pointers
596 can be different and may require different integer to pointer
598 if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_INT
599 && (TYPE_LENGTH (VALUE_TYPE (val
))
600 <= TYPE_LENGTH (builtin_type_void_data_ptr
)))
602 val
= value_cast (builtin_type_void_data_ptr
, val
);
604 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
608 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
609 as a long, or as a double, assuming the raw data is described
610 by type TYPE. Knows how to convert different sizes of values
611 and can convert between fixed and floating point. We don't assume
612 any alignment for the raw data. Return value is in host byte order.
614 If you want functions and arrays to be coerced to pointers, and
615 references to be dereferenced, call value_as_long() instead.
617 C++: It is assumed that the front-end has taken care of
618 all matters concerning pointers to members. A pointer
619 to member which reaches here is considered to be equivalent
620 to an INT (or some size). After all, it is only an offset. */
623 unpack_long (struct type
*type
, char *valaddr
)
625 register enum type_code code
= TYPE_CODE (type
);
626 register int len
= TYPE_LENGTH (type
);
627 register int nosign
= TYPE_UNSIGNED (type
);
629 if (current_language
->la_language
== language_scm
630 && is_scmvalue_type (type
))
631 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
635 case TYPE_CODE_TYPEDEF
:
636 return unpack_long (check_typedef (type
), valaddr
);
641 case TYPE_CODE_RANGE
:
643 return extract_unsigned_integer (valaddr
, len
);
645 return extract_signed_integer (valaddr
, len
);
648 return extract_typed_floating (valaddr
, type
);
652 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
653 whether we want this to be true eventually. */
654 return extract_typed_address (valaddr
, type
);
656 case TYPE_CODE_MEMBER
:
657 error ("not implemented: member types in unpack_long");
660 error ("Value can't be converted to integer.");
662 return 0; /* Placate lint. */
665 /* Return a double value from the specified type and address.
666 INVP points to an int which is set to 0 for valid value,
667 1 for invalid value (bad float format). In either case,
668 the returned double is OK to use. Argument is in target
669 format, result is in host format. */
672 unpack_double (struct type
*type
, char *valaddr
, int *invp
)
678 *invp
= 0; /* Assume valid. */
679 CHECK_TYPEDEF (type
);
680 code
= TYPE_CODE (type
);
681 len
= TYPE_LENGTH (type
);
682 nosign
= TYPE_UNSIGNED (type
);
683 if (code
== TYPE_CODE_FLT
)
686 if (INVALID_FLOAT (valaddr
, len
))
689 return 1.234567891011121314;
692 return extract_typed_floating (valaddr
, type
);
696 /* Unsigned -- be sure we compensate for signed LONGEST. */
697 return (ULONGEST
) unpack_long (type
, valaddr
);
701 /* Signed -- we are OK with unpack_long. */
702 return unpack_long (type
, valaddr
);
706 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
707 as a CORE_ADDR, assuming the raw data is described by type TYPE.
708 We don't assume any alignment for the raw data. Return value is in
711 If you want functions and arrays to be coerced to pointers, and
712 references to be dereferenced, call value_as_pointer() instead.
714 C++: It is assumed that the front-end has taken care of
715 all matters concerning pointers to members. A pointer
716 to member which reaches here is considered to be equivalent
717 to an INT (or some size). After all, it is only an offset. */
720 unpack_pointer (struct type
*type
, char *valaddr
)
722 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
723 whether we want this to be true eventually. */
724 return unpack_long (type
, valaddr
);
728 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
731 value_static_field (struct type
*type
, int fieldno
)
735 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
737 addr
= TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
);
742 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
743 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_NAMESPACE
, 0, NULL
);
746 /* With some compilers, e.g. HP aCC, static data members are reported
747 as non-debuggable symbols */
748 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
753 addr
= SYMBOL_VALUE_ADDRESS (msym
);
754 sect
= SYMBOL_BFD_SECTION (msym
);
759 /* Anything static that isn't a constant, has an address */
760 if (SYMBOL_CLASS (sym
) != LOC_CONST
)
762 addr
= SYMBOL_VALUE_ADDRESS (sym
);
763 sect
= SYMBOL_BFD_SECTION (sym
);
765 /* However, static const's do not, the value is already known. */
768 return value_from_longest (TYPE_FIELD_TYPE (type
, fieldno
), SYMBOL_VALUE (sym
));
771 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
), addr
);
773 return value_at (TYPE_FIELD_TYPE (type
, fieldno
), addr
, sect
);
776 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
777 You have to be careful here, since the size of the data area for the value
778 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
779 than the old enclosing type, you have to allocate more space for the data.
780 The return value is a pointer to the new version of this value structure. */
783 value_change_enclosing_type (value_ptr val
, struct type
*new_encl_type
)
785 if (TYPE_LENGTH (new_encl_type
) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val
)))
787 VALUE_ENCLOSING_TYPE (val
) = new_encl_type
;
793 register value_ptr prev
;
795 new_val
= (value_ptr
) xrealloc (val
, sizeof (struct value
) + TYPE_LENGTH (new_encl_type
));
797 /* We have to make sure this ends up in the same place in the value
798 chain as the original copy, so it's clean-up behavior is the same.
799 If the value has been released, this is a waste of time, but there
800 is no way to tell that in advance, so... */
802 if (val
!= all_values
)
804 for (prev
= all_values
; prev
!= NULL
; prev
= prev
->next
)
806 if (prev
->next
== val
)
808 prev
->next
= new_val
;
818 /* Given a value ARG1 (offset by OFFSET bytes)
819 of a struct or union type ARG_TYPE,
820 extract and return the value of one of its (non-static) fields.
821 FIELDNO says which field. */
824 value_primitive_field (register value_ptr arg1
, int offset
,
825 register int fieldno
, register struct type
*arg_type
)
827 register value_ptr v
;
828 register struct type
*type
;
830 CHECK_TYPEDEF (arg_type
);
831 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
833 /* Handle packed fields */
835 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
837 v
= value_from_longest (type
,
838 unpack_field_as_long (arg_type
,
839 VALUE_CONTENTS (arg1
)
842 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
843 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
844 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
845 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
847 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
849 /* This field is actually a base subobject, so preserve the
850 entire object's contents for later references to virtual
852 v
= allocate_value (VALUE_ENCLOSING_TYPE (arg1
));
853 VALUE_TYPE (v
) = type
;
854 if (VALUE_LAZY (arg1
))
857 memcpy (VALUE_CONTENTS_ALL_RAW (v
), VALUE_CONTENTS_ALL_RAW (arg1
),
858 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1
)));
859 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
);
860 VALUE_EMBEDDED_OFFSET (v
)
862 VALUE_EMBEDDED_OFFSET (arg1
) +
863 TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
867 /* Plain old data member */
868 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
869 v
= allocate_value (type
);
870 if (VALUE_LAZY (arg1
))
873 memcpy (VALUE_CONTENTS_RAW (v
),
874 VALUE_CONTENTS_RAW (arg1
) + offset
,
876 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
;
878 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
879 if (VALUE_LVAL (arg1
) == lval_internalvar
)
880 VALUE_LVAL (v
) = lval_internalvar_component
;
881 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
882 VALUE_REGNO (v
) = VALUE_REGNO (arg1
);
883 /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
884 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
888 /* Given a value ARG1 of a struct or union type,
889 extract and return the value of one of its (non-static) fields.
890 FIELDNO says which field. */
893 value_field (register value_ptr arg1
, register int fieldno
)
895 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
898 /* Return a non-virtual function as a value.
899 F is the list of member functions which contains the desired method.
900 J is an index into F which provides the desired method. */
903 value_fn_field (value_ptr
*arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
906 register value_ptr v
;
907 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
910 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
911 0, VAR_NAMESPACE
, 0, NULL
);
915 error ("Internal error: could not find physical method named %s",
916 TYPE_FN_FIELD_PHYSNAME (f, j));
919 v
= allocate_value (ftype
);
920 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
921 VALUE_TYPE (v
) = ftype
;
925 if (type
!= VALUE_TYPE (*arg1p
))
926 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
927 value_addr (*arg1p
)));
929 /* Move the `this' pointer according to the offset.
930 VALUE_OFFSET (*arg1p) += offset;
937 /* ARG is a pointer to an object we know to be at least
938 a DTYPE. BTYPE is the most derived basetype that has
939 already been searched (and need not be searched again).
940 After looking at the vtables between BTYPE and DTYPE,
941 return the most derived type we find. The caller must
942 be satisfied when the return value == DTYPE.
944 FIXME-tiemann: should work with dossier entries as well.
945 NOTICE - djb: I see no good reason at all to keep this function now that
946 we have RTTI support. It's used in literally one place, and it's
947 hard to keep this function up to date when it's purpose is served
948 by value_rtti_type efficiently.
949 Consider it gone for 5.1. */
952 value_headof (value_ptr in_arg
, struct type
*btype
, struct type
*dtype
)
954 /* First collect the vtables we must look at for this object. */
957 char *demangled_name
;
958 struct minimal_symbol
*msymbol
;
960 btype
= TYPE_VPTR_BASETYPE (dtype
);
961 CHECK_TYPEDEF (btype
);
964 arg
= value_cast (lookup_pointer_type (btype
), arg
);
965 if (TYPE_CODE (VALUE_TYPE (arg
)) == TYPE_CODE_REF
)
968 * Copy the value, but change the type from (T&) to (T*).
969 * We keep the same location information, which is efficient,
970 * and allows &(&X) to get the location containing the reference.
972 arg
= value_copy (arg
);
973 VALUE_TYPE (arg
) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg
)));
975 if (VALUE_ADDRESS(value_field (value_ind(arg
), TYPE_VPTR_FIELDNO (btype
)))==0)
978 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
979 /* Turn vtable into typeinfo function */
980 VALUE_OFFSET(vtbl
)+=4;
982 msymbol
= lookup_minimal_symbol_by_pc ( value_as_pointer(value_ind(vtbl
)) );
984 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
)
986 /* If we expected to find a vtable, but did not, let the user
987 know that we aren't happy, but don't throw an error.
988 FIXME: there has to be a better way to do this. */
989 struct type
*error_type
= (struct type
*) xmalloc (sizeof (struct type
));
990 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
991 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
992 VALUE_TYPE (in_arg
) = error_type
;
995 demangled_name
= cplus_demangle(demangled_name
,DMGL_ANSI
);
996 *(strchr (demangled_name
, ' ')) = '\0';
998 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
1000 error ("could not find type declaration for `%s'", demangled_name
);
1003 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1007 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1008 function tables, probe ARG's tables (including the vtables
1009 of its baseclasses) to figure out the most derived type that ARG
1010 could actually be a pointer to. */
1013 value_from_vtable_info (value_ptr arg
, struct type
*type
)
1015 /* Take care of preliminaries. */
1016 if (TYPE_VPTR_FIELDNO (type
) < 0)
1017 fill_in_vptr_fieldno (type
);
1018 if (TYPE_VPTR_FIELDNO (type
) < 0)
1021 return value_headof (arg
, 0, type
);
1024 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1025 pointer which is for the base class whose type is BASECLASS. */
1028 vb_match (struct type
*type
, int index
, struct type
*basetype
)
1030 struct type
*fieldtype
;
1031 char *name
= TYPE_FIELD_NAME (type
, index
);
1032 char *field_class_name
= NULL
;
1036 /* gcc 2.4 uses _vb$. */
1037 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
1038 field_class_name
= name
+ 4;
1039 /* gcc 2.5 will use __vb_. */
1040 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1041 field_class_name
= name
+ 5;
1043 if (field_class_name
== NULL
)
1044 /* This field is not a virtual base class pointer. */
1047 /* It's a virtual baseclass pointer, now we just need to find out whether
1048 it is for this baseclass. */
1049 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1050 if (fieldtype
== NULL
1051 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1052 /* "Can't happen". */
1055 /* What we check for is that either the types are equal (needed for
1056 nameless types) or have the same name. This is ugly, and a more
1057 elegant solution should be devised (which would probably just push
1058 the ugliness into symbol reading unless we change the stabs format). */
1059 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1062 if (TYPE_NAME (basetype
) != NULL
1063 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1064 && STREQ (TYPE_NAME (basetype
),
1065 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1070 /* Compute the offset of the baseclass which is
1071 the INDEXth baseclass of class TYPE,
1072 for value at VALADDR (in host) at ADDRESS (in target).
1073 The result is the offset of the baseclass value relative
1074 to (the address of)(ARG) + OFFSET.
1076 -1 is returned on error. */
1079 baseclass_offset (struct type
*type
, int index
, char *valaddr
,
1082 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1084 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1086 /* Must hunt for the pointer to this virtual baseclass. */
1087 register int i
, len
= TYPE_NFIELDS (type
);
1088 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1090 /* First look for the virtual baseclass pointer
1092 for (i
= n_baseclasses
; i
< len
; i
++)
1094 if (vb_match (type
, i
, basetype
))
1097 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1098 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1100 return addr
- (LONGEST
) address
;
1103 /* Not in the fields, so try looking through the baseclasses. */
1104 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
1107 baseclass_offset (type
, i
, valaddr
, address
);
1115 /* Baseclass is easily computed. */
1116 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1119 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1122 Extracting bits depends on endianness of the machine. Compute the
1123 number of least significant bits to discard. For big endian machines,
1124 we compute the total number of bits in the anonymous object, subtract
1125 off the bit count from the MSB of the object to the MSB of the
1126 bitfield, then the size of the bitfield, which leaves the LSB discard
1127 count. For little endian machines, the discard count is simply the
1128 number of bits from the LSB of the anonymous object to the LSB of the
1131 If the field is signed, we also do sign extension. */
1134 unpack_field_as_long (struct type
*type
, char *valaddr
, int fieldno
)
1138 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1139 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1141 struct type
*field_type
;
1143 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1144 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1145 CHECK_TYPEDEF (field_type
);
1147 /* Extract bits. See comment above. */
1149 if (BITS_BIG_ENDIAN
)
1150 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1152 lsbcount
= (bitpos
% 8);
1155 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1156 If the field is signed, and is negative, then sign extend. */
1158 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1160 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1162 if (!TYPE_UNSIGNED (field_type
))
1164 if (val
& (valmask
^ (valmask
>> 1)))
1173 /* Modify the value of a bitfield. ADDR points to a block of memory in
1174 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1175 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1176 indicate which bits (in target bit order) comprise the bitfield. */
1179 modify_field (char *addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1183 /* If a negative fieldval fits in the field in question, chop
1184 off the sign extension bits. */
1185 if (bitsize
< (8 * (int) sizeof (fieldval
))
1186 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1187 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1189 /* Warn if value is too big to fit in the field in question. */
1190 if (bitsize
< (8 * (int) sizeof (fieldval
))
1191 && 0 != (fieldval
& ~((1 << bitsize
) - 1)))
1193 /* FIXME: would like to include fieldval in the message, but
1194 we don't have a sprintf_longest. */
1195 warning ("Value does not fit in %d bits.", bitsize
);
1197 /* Truncate it, otherwise adjoining fields may be corrupted. */
1198 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1201 oword
= extract_signed_integer (addr
, sizeof oword
);
1203 /* Shifting for bit field depends on endianness of the target machine. */
1204 if (BITS_BIG_ENDIAN
)
1205 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1207 /* Mask out old value, while avoiding shifts >= size of oword */
1208 if (bitsize
< 8 * (int) sizeof (oword
))
1209 oword
&= ~(((((ULONGEST
) 1) << bitsize
) - 1) << bitpos
);
1211 oword
&= ~((~(ULONGEST
) 0) << bitpos
);
1212 oword
|= fieldval
<< bitpos
;
1214 store_signed_integer (addr
, sizeof oword
, oword
);
1217 /* Convert C numbers into newly allocated values */
1220 value_from_longest (struct type
*type
, register LONGEST num
)
1222 register value_ptr val
= allocate_value (type
);
1223 register enum type_code code
;
1226 code
= TYPE_CODE (type
);
1227 len
= TYPE_LENGTH (type
);
1231 case TYPE_CODE_TYPEDEF
:
1232 type
= check_typedef (type
);
1235 case TYPE_CODE_CHAR
:
1236 case TYPE_CODE_ENUM
:
1237 case TYPE_CODE_BOOL
:
1238 case TYPE_CODE_RANGE
:
1239 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1244 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, (CORE_ADDR
) num
);
1248 error ("Unexpected type (%d) encountered for integer constant.", code
);
1254 /* Create a value representing a pointer of type TYPE to the address
1257 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
1259 value_ptr val
= allocate_value (type
);
1260 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, addr
);
1265 /* Create a value for a string constant to be stored locally
1266 (not in the inferior's memory space, but in GDB memory).
1267 This is analogous to value_from_longest, which also does not
1268 use inferior memory. String shall NOT contain embedded nulls. */
1271 value_from_string (char *ptr
)
1274 int len
= strlen (ptr
);
1275 int lowbound
= current_language
->string_lower_bound
;
1276 struct type
*rangetype
=
1277 create_range_type ((struct type
*) NULL
,
1279 lowbound
, len
+ lowbound
- 1);
1280 struct type
*stringtype
=
1281 create_array_type ((struct type
*) NULL
,
1282 *current_language
->string_char_type
,
1285 val
= allocate_value (stringtype
);
1286 memcpy (VALUE_CONTENTS_RAW (val
), ptr
, len
);
1291 value_from_double (struct type
*type
, DOUBLEST num
)
1293 register value_ptr val
= allocate_value (type
);
1294 struct type
*base_type
= check_typedef (type
);
1295 register enum type_code code
= TYPE_CODE (base_type
);
1296 register int len
= TYPE_LENGTH (base_type
);
1298 if (code
== TYPE_CODE_FLT
)
1300 store_typed_floating (VALUE_CONTENTS_RAW (val
), base_type
, num
);
1303 error ("Unexpected type encountered for floating constant.");
1308 /* Deal with the value that is "about to be returned". */
1310 /* Return the value that a function returning now
1311 would be returning to its caller, assuming its type is VALTYPE.
1312 RETBUF is where we look for what ought to be the contents
1313 of the registers (in raw form). This is because it is often
1314 desirable to restore old values to those registers
1315 after saving the contents of interest, and then call
1316 this function using the saved values.
1317 struct_return is non-zero when the function in question is
1318 using the structure return conventions on the machine in question;
1319 0 when it is using the value returning conventions (this often
1320 means returning pointer to where structure is vs. returning value). */
1324 value_being_returned (struct type
*valtype
, char *retbuf
, int struct_return
)
1326 register value_ptr val
;
1329 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1330 if (EXTRACT_STRUCT_VALUE_ADDRESS_P ())
1333 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1335 error ("Function return value unknown");
1336 return value_at (valtype
, addr
, NULL
);
1339 val
= allocate_value (valtype
);
1340 CHECK_TYPEDEF (valtype
);
1341 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1346 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1347 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1348 and TYPE is the type (which is known to be struct, union or array).
1350 On most machines, the struct convention is used unless we are
1351 using gcc and the type is of a special size. */
1352 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1353 native compiler. GCC 2.3.3 was the last release that did it the
1354 old way. Since gcc2_compiled was not changed, we have no
1355 way to correctly win in all cases, so we just do the right thing
1356 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1357 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1358 would cause more chaos than dealing with some struct returns being
1362 generic_use_struct_convention (int gcc_p
, struct type
*value_type
)
1364 return !((gcc_p
== 1)
1365 && (TYPE_LENGTH (value_type
) == 1
1366 || TYPE_LENGTH (value_type
) == 2
1367 || TYPE_LENGTH (value_type
) == 4
1368 || TYPE_LENGTH (value_type
) == 8));
1371 #ifndef USE_STRUCT_CONVENTION
1372 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1376 /* Return true if the function specified is using the structure returning
1377 convention on this machine to return arguments, or 0 if it is using
1378 the value returning convention. FUNCTION is the value representing
1379 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1380 is the type returned by the function. GCC_P is nonzero if compiled
1385 using_struct_return (value_ptr function
, CORE_ADDR funcaddr
,
1386 struct type
*value_type
, int gcc_p
)
1388 register enum type_code code
= TYPE_CODE (value_type
);
1390 if (code
== TYPE_CODE_ERROR
)
1391 error ("Function return type unknown.");
1393 if (code
== TYPE_CODE_STRUCT
1394 || code
== TYPE_CODE_UNION
1395 || code
== TYPE_CODE_ARRAY
1396 || RETURN_VALUE_ON_STACK (value_type
))
1397 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1402 /* Store VAL so it will be returned if a function returns now.
1403 Does not verify that VAL's type matches what the current
1404 function wants to return. */
1407 set_return_value (value_ptr val
)
1409 struct type
*type
= check_typedef (VALUE_TYPE (val
));
1410 register enum type_code code
= TYPE_CODE (type
);
1412 if (code
== TYPE_CODE_ERROR
)
1413 error ("Function return type unknown.");
1415 if (code
== TYPE_CODE_STRUCT
1416 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1417 error ("GDB does not support specifying a struct or union return value.");
1419 STORE_RETURN_VALUE (type
, VALUE_CONTENTS (val
));
1423 _initialize_values (void)
1425 add_cmd ("convenience", no_class
, show_convenience
,
1426 "Debugger convenience (\"$foo\") variables.\n\
1427 These variables are created when you assign them values;\n\
1428 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1429 A few convenience variables are given values automatically:\n\
1430 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1431 \"$__\" holds the contents of the last address examined with \"x\".",
1434 add_cmd ("values", no_class
, show_values
,
1435 "Elements of value history around item number IDX (or last ten).",