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_address (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
));
576 /* Some architectures (e.g. Harvard), map instruction and data
577 addresses onto a single large unified address space. For
578 instance: An architecture may consider a large integer in the
579 range 0x10000000 .. 0x1000ffff to already represent a data
580 addresses (hence not need a pointer to address conversion) while
581 a small integer would still need to be converted integer to
582 pointer to address. Just assume such architectures handle all
583 integer conversions in a single function. */
587 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
588 must admonish GDB hackers to make sure its behavior matches the
589 compiler's, whenever possible.
591 In general, I think GDB should evaluate expressions the same way
592 the compiler does. When the user copies an expression out of
593 their source code and hands it to a `print' command, they should
594 get the same value the compiler would have computed. Any
595 deviation from this rule can cause major confusion and annoyance,
596 and needs to be justified carefully. In other words, GDB doesn't
597 really have the freedom to do these conversions in clever and
600 AndrewC pointed out that users aren't complaining about how GDB
601 casts integers to pointers; they are complaining that they can't
602 take an address from a disassembly listing and give it to `x/i'.
603 This is certainly important.
605 Adding an architecture method like INTEGER_TO_ADDRESS certainly
606 makes it possible for GDB to "get it right" in all circumstances
607 --- the target has complete control over how things get done, so
608 people can Do The Right Thing for their target without breaking
609 anyone else. The standard doesn't specify how integers get
610 converted to pointers; usually, the ABI doesn't either, but
611 ABI-specific code is a more reasonable place to handle it. */
613 if (TYPE_CODE (VALUE_TYPE (val
)) != TYPE_CODE_PTR
614 && TYPE_CODE (VALUE_TYPE (val
)) != TYPE_CODE_REF
615 && INTEGER_TO_ADDRESS_P ())
616 return INTEGER_TO_ADDRESS (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
618 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
622 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
623 as a long, or as a double, assuming the raw data is described
624 by type TYPE. Knows how to convert different sizes of values
625 and can convert between fixed and floating point. We don't assume
626 any alignment for the raw data. Return value is in host byte order.
628 If you want functions and arrays to be coerced to pointers, and
629 references to be dereferenced, call value_as_long() instead.
631 C++: It is assumed that the front-end has taken care of
632 all matters concerning pointers to members. A pointer
633 to member which reaches here is considered to be equivalent
634 to an INT (or some size). After all, it is only an offset. */
637 unpack_long (struct type
*type
, char *valaddr
)
639 register enum type_code code
= TYPE_CODE (type
);
640 register int len
= TYPE_LENGTH (type
);
641 register int nosign
= TYPE_UNSIGNED (type
);
643 if (current_language
->la_language
== language_scm
644 && is_scmvalue_type (type
))
645 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
649 case TYPE_CODE_TYPEDEF
:
650 return unpack_long (check_typedef (type
), valaddr
);
655 case TYPE_CODE_RANGE
:
657 return extract_unsigned_integer (valaddr
, len
);
659 return extract_signed_integer (valaddr
, len
);
662 return extract_typed_floating (valaddr
, type
);
666 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
667 whether we want this to be true eventually. */
668 return extract_typed_address (valaddr
, type
);
670 case TYPE_CODE_MEMBER
:
671 error ("not implemented: member types in unpack_long");
674 error ("Value can't be converted to integer.");
676 return 0; /* Placate lint. */
679 /* Return a double value from the specified type and address.
680 INVP points to an int which is set to 0 for valid value,
681 1 for invalid value (bad float format). In either case,
682 the returned double is OK to use. Argument is in target
683 format, result is in host format. */
686 unpack_double (struct type
*type
, char *valaddr
, int *invp
)
692 *invp
= 0; /* Assume valid. */
693 CHECK_TYPEDEF (type
);
694 code
= TYPE_CODE (type
);
695 len
= TYPE_LENGTH (type
);
696 nosign
= TYPE_UNSIGNED (type
);
697 if (code
== TYPE_CODE_FLT
)
700 if (INVALID_FLOAT (valaddr
, len
))
703 return 1.234567891011121314;
706 return extract_typed_floating (valaddr
, type
);
710 /* Unsigned -- be sure we compensate for signed LONGEST. */
711 return (ULONGEST
) unpack_long (type
, valaddr
);
715 /* Signed -- we are OK with unpack_long. */
716 return unpack_long (type
, valaddr
);
720 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
721 as a CORE_ADDR, assuming the raw data is described by type TYPE.
722 We don't assume any alignment for the raw data. Return value is in
725 If you want functions and arrays to be coerced to pointers, and
726 references to be dereferenced, call value_as_address() instead.
728 C++: It is assumed that the front-end has taken care of
729 all matters concerning pointers to members. A pointer
730 to member which reaches here is considered to be equivalent
731 to an INT (or some size). After all, it is only an offset. */
734 unpack_pointer (struct type
*type
, char *valaddr
)
736 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
737 whether we want this to be true eventually. */
738 return unpack_long (type
, valaddr
);
742 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
745 value_static_field (struct type
*type
, int fieldno
)
749 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
751 addr
= TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
);
756 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
757 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_NAMESPACE
, 0, NULL
);
760 /* With some compilers, e.g. HP aCC, static data members are reported
761 as non-debuggable symbols */
762 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
767 addr
= SYMBOL_VALUE_ADDRESS (msym
);
768 sect
= SYMBOL_BFD_SECTION (msym
);
773 /* Anything static that isn't a constant, has an address */
774 if (SYMBOL_CLASS (sym
) != LOC_CONST
)
776 addr
= SYMBOL_VALUE_ADDRESS (sym
);
777 sect
= SYMBOL_BFD_SECTION (sym
);
779 /* However, static const's do not, the value is already known. */
782 return value_from_longest (TYPE_FIELD_TYPE (type
, fieldno
), SYMBOL_VALUE (sym
));
785 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
), addr
);
787 return value_at (TYPE_FIELD_TYPE (type
, fieldno
), addr
, sect
);
790 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
791 You have to be careful here, since the size of the data area for the value
792 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
793 than the old enclosing type, you have to allocate more space for the data.
794 The return value is a pointer to the new version of this value structure. */
797 value_change_enclosing_type (value_ptr val
, struct type
*new_encl_type
)
799 if (TYPE_LENGTH (new_encl_type
) <= TYPE_LENGTH (VALUE_ENCLOSING_TYPE (val
)))
801 VALUE_ENCLOSING_TYPE (val
) = new_encl_type
;
807 register value_ptr prev
;
809 new_val
= (value_ptr
) xrealloc (val
, sizeof (struct value
) + TYPE_LENGTH (new_encl_type
));
811 /* We have to make sure this ends up in the same place in the value
812 chain as the original copy, so it's clean-up behavior is the same.
813 If the value has been released, this is a waste of time, but there
814 is no way to tell that in advance, so... */
816 if (val
!= all_values
)
818 for (prev
= all_values
; prev
!= NULL
; prev
= prev
->next
)
820 if (prev
->next
== val
)
822 prev
->next
= new_val
;
832 /* Given a value ARG1 (offset by OFFSET bytes)
833 of a struct or union type ARG_TYPE,
834 extract and return the value of one of its (non-static) fields.
835 FIELDNO says which field. */
838 value_primitive_field (register value_ptr arg1
, int offset
,
839 register int fieldno
, register struct type
*arg_type
)
841 register value_ptr v
;
842 register struct type
*type
;
844 CHECK_TYPEDEF (arg_type
);
845 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
847 /* Handle packed fields */
849 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
851 v
= value_from_longest (type
,
852 unpack_field_as_long (arg_type
,
853 VALUE_CONTENTS (arg1
)
856 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
857 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
858 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
859 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
861 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
863 /* This field is actually a base subobject, so preserve the
864 entire object's contents for later references to virtual
866 v
= allocate_value (VALUE_ENCLOSING_TYPE (arg1
));
867 VALUE_TYPE (v
) = type
;
868 if (VALUE_LAZY (arg1
))
871 memcpy (VALUE_CONTENTS_ALL_RAW (v
), VALUE_CONTENTS_ALL_RAW (arg1
),
872 TYPE_LENGTH (VALUE_ENCLOSING_TYPE (arg1
)));
873 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
);
874 VALUE_EMBEDDED_OFFSET (v
)
876 VALUE_EMBEDDED_OFFSET (arg1
) +
877 TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
881 /* Plain old data member */
882 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
883 v
= allocate_value (type
);
884 if (VALUE_LAZY (arg1
))
887 memcpy (VALUE_CONTENTS_RAW (v
),
888 VALUE_CONTENTS_RAW (arg1
) + offset
,
890 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
;
892 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
893 if (VALUE_LVAL (arg1
) == lval_internalvar
)
894 VALUE_LVAL (v
) = lval_internalvar_component
;
895 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
896 VALUE_REGNO (v
) = VALUE_REGNO (arg1
);
897 /* VALUE_OFFSET (v) = VALUE_OFFSET (arg1) + offset
898 + TYPE_FIELD_BITPOS (arg_type, fieldno) / 8; */
902 /* Given a value ARG1 of a struct or union type,
903 extract and return the value of one of its (non-static) fields.
904 FIELDNO says which field. */
907 value_field (register value_ptr arg1
, register int fieldno
)
909 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
912 /* Return a non-virtual function as a value.
913 F is the list of member functions which contains the desired method.
914 J is an index into F which provides the desired method. */
917 value_fn_field (value_ptr
*arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
920 register value_ptr v
;
921 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
924 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
925 0, VAR_NAMESPACE
, 0, NULL
);
929 error ("Internal error: could not find physical method named %s",
930 TYPE_FN_FIELD_PHYSNAME (f, j));
933 v
= allocate_value (ftype
);
934 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
935 VALUE_TYPE (v
) = ftype
;
939 if (type
!= VALUE_TYPE (*arg1p
))
940 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
941 value_addr (*arg1p
)));
943 /* Move the `this' pointer according to the offset.
944 VALUE_OFFSET (*arg1p) += offset;
951 /* ARG is a pointer to an object we know to be at least
952 a DTYPE. BTYPE is the most derived basetype that has
953 already been searched (and need not be searched again).
954 After looking at the vtables between BTYPE and DTYPE,
955 return the most derived type we find. The caller must
956 be satisfied when the return value == DTYPE.
958 FIXME-tiemann: should work with dossier entries as well.
959 NOTICE - djb: I see no good reason at all to keep this function now that
960 we have RTTI support. It's used in literally one place, and it's
961 hard to keep this function up to date when it's purpose is served
962 by value_rtti_type efficiently.
963 Consider it gone for 5.1. */
966 value_headof (value_ptr in_arg
, struct type
*btype
, struct type
*dtype
)
968 /* First collect the vtables we must look at for this object. */
971 char *demangled_name
;
972 struct minimal_symbol
*msymbol
;
974 btype
= TYPE_VPTR_BASETYPE (dtype
);
975 CHECK_TYPEDEF (btype
);
978 arg
= value_cast (lookup_pointer_type (btype
), arg
);
979 if (TYPE_CODE (VALUE_TYPE (arg
)) == TYPE_CODE_REF
)
982 * Copy the value, but change the type from (T&) to (T*).
983 * We keep the same location information, which is efficient,
984 * and allows &(&X) to get the location containing the reference.
986 arg
= value_copy (arg
);
987 VALUE_TYPE (arg
) = lookup_pointer_type (TYPE_TARGET_TYPE (VALUE_TYPE (arg
)));
989 if (VALUE_ADDRESS(value_field (value_ind(arg
), TYPE_VPTR_FIELDNO (btype
)))==0)
992 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
993 /* Turn vtable into typeinfo function */
994 VALUE_OFFSET(vtbl
)+=4;
996 msymbol
= lookup_minimal_symbol_by_pc ( value_as_address(value_ind(vtbl
)) );
998 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
)
1000 /* If we expected to find a vtable, but did not, let the user
1001 know that we aren't happy, but don't throw an error.
1002 FIXME: there has to be a better way to do this. */
1003 struct type
*error_type
= (struct type
*) xmalloc (sizeof (struct type
));
1004 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
1005 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
1006 VALUE_TYPE (in_arg
) = error_type
;
1009 demangled_name
= cplus_demangle(demangled_name
,DMGL_ANSI
);
1010 *(strchr (demangled_name
, ' ')) = '\0';
1012 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
1014 error ("could not find type declaration for `%s'", demangled_name
);
1017 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1021 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1022 function tables, probe ARG's tables (including the vtables
1023 of its baseclasses) to figure out the most derived type that ARG
1024 could actually be a pointer to. */
1027 value_from_vtable_info (value_ptr arg
, struct type
*type
)
1029 /* Take care of preliminaries. */
1030 if (TYPE_VPTR_FIELDNO (type
) < 0)
1031 fill_in_vptr_fieldno (type
);
1032 if (TYPE_VPTR_FIELDNO (type
) < 0)
1035 return value_headof (arg
, 0, type
);
1038 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1039 pointer which is for the base class whose type is BASECLASS. */
1042 vb_match (struct type
*type
, int index
, struct type
*basetype
)
1044 struct type
*fieldtype
;
1045 char *name
= TYPE_FIELD_NAME (type
, index
);
1046 char *field_class_name
= NULL
;
1050 /* gcc 2.4 uses _vb$. */
1051 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
1052 field_class_name
= name
+ 4;
1053 /* gcc 2.5 will use __vb_. */
1054 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1055 field_class_name
= name
+ 5;
1057 if (field_class_name
== NULL
)
1058 /* This field is not a virtual base class pointer. */
1061 /* It's a virtual baseclass pointer, now we just need to find out whether
1062 it is for this baseclass. */
1063 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1064 if (fieldtype
== NULL
1065 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1066 /* "Can't happen". */
1069 /* What we check for is that either the types are equal (needed for
1070 nameless types) or have the same name. This is ugly, and a more
1071 elegant solution should be devised (which would probably just push
1072 the ugliness into symbol reading unless we change the stabs format). */
1073 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1076 if (TYPE_NAME (basetype
) != NULL
1077 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1078 && STREQ (TYPE_NAME (basetype
),
1079 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1084 /* Compute the offset of the baseclass which is
1085 the INDEXth baseclass of class TYPE,
1086 for value at VALADDR (in host) at ADDRESS (in target).
1087 The result is the offset of the baseclass value relative
1088 to (the address of)(ARG) + OFFSET.
1090 -1 is returned on error. */
1093 baseclass_offset (struct type
*type
, int index
, char *valaddr
,
1096 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1098 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1100 /* Must hunt for the pointer to this virtual baseclass. */
1101 register int i
, len
= TYPE_NFIELDS (type
);
1102 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1104 /* First look for the virtual baseclass pointer
1106 for (i
= n_baseclasses
; i
< len
; i
++)
1108 if (vb_match (type
, i
, basetype
))
1111 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1112 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1114 return addr
- (LONGEST
) address
;
1117 /* Not in the fields, so try looking through the baseclasses. */
1118 for (i
= index
+ 1; i
< n_baseclasses
; i
++)
1121 baseclass_offset (type
, i
, valaddr
, address
);
1129 /* Baseclass is easily computed. */
1130 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1133 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1136 Extracting bits depends on endianness of the machine. Compute the
1137 number of least significant bits to discard. For big endian machines,
1138 we compute the total number of bits in the anonymous object, subtract
1139 off the bit count from the MSB of the object to the MSB of the
1140 bitfield, then the size of the bitfield, which leaves the LSB discard
1141 count. For little endian machines, the discard count is simply the
1142 number of bits from the LSB of the anonymous object to the LSB of the
1145 If the field is signed, we also do sign extension. */
1148 unpack_field_as_long (struct type
*type
, char *valaddr
, int fieldno
)
1152 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1153 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1155 struct type
*field_type
;
1157 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1158 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1159 CHECK_TYPEDEF (field_type
);
1161 /* Extract bits. See comment above. */
1163 if (BITS_BIG_ENDIAN
)
1164 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1166 lsbcount
= (bitpos
% 8);
1169 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1170 If the field is signed, and is negative, then sign extend. */
1172 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1174 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1176 if (!TYPE_UNSIGNED (field_type
))
1178 if (val
& (valmask
^ (valmask
>> 1)))
1187 /* Modify the value of a bitfield. ADDR points to a block of memory in
1188 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1189 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1190 indicate which bits (in target bit order) comprise the bitfield. */
1193 modify_field (char *addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
1197 /* If a negative fieldval fits in the field in question, chop
1198 off the sign extension bits. */
1199 if (bitsize
< (8 * (int) sizeof (fieldval
))
1200 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1201 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1203 /* Warn if value is too big to fit in the field in question. */
1204 if (bitsize
< (8 * (int) sizeof (fieldval
))
1205 && 0 != (fieldval
& ~((1 << bitsize
) - 1)))
1207 /* FIXME: would like to include fieldval in the message, but
1208 we don't have a sprintf_longest. */
1209 warning ("Value does not fit in %d bits.", bitsize
);
1211 /* Truncate it, otherwise adjoining fields may be corrupted. */
1212 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1215 oword
= extract_signed_integer (addr
, sizeof oword
);
1217 /* Shifting for bit field depends on endianness of the target machine. */
1218 if (BITS_BIG_ENDIAN
)
1219 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1221 /* Mask out old value, while avoiding shifts >= size of oword */
1222 if (bitsize
< 8 * (int) sizeof (oword
))
1223 oword
&= ~(((((ULONGEST
) 1) << bitsize
) - 1) << bitpos
);
1225 oword
&= ~((~(ULONGEST
) 0) << bitpos
);
1226 oword
|= fieldval
<< bitpos
;
1228 store_signed_integer (addr
, sizeof oword
, oword
);
1231 /* Convert C numbers into newly allocated values */
1234 value_from_longest (struct type
*type
, register LONGEST num
)
1236 register value_ptr val
= allocate_value (type
);
1237 register enum type_code code
;
1240 code
= TYPE_CODE (type
);
1241 len
= TYPE_LENGTH (type
);
1245 case TYPE_CODE_TYPEDEF
:
1246 type
= check_typedef (type
);
1249 case TYPE_CODE_CHAR
:
1250 case TYPE_CODE_ENUM
:
1251 case TYPE_CODE_BOOL
:
1252 case TYPE_CODE_RANGE
:
1253 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1258 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, (CORE_ADDR
) num
);
1262 error ("Unexpected type (%d) encountered for integer constant.", code
);
1268 /* Create a value representing a pointer of type TYPE to the address
1271 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
1273 value_ptr val
= allocate_value (type
);
1274 store_typed_address (VALUE_CONTENTS_RAW (val
), type
, addr
);
1279 /* Create a value for a string constant to be stored locally
1280 (not in the inferior's memory space, but in GDB memory).
1281 This is analogous to value_from_longest, which also does not
1282 use inferior memory. String shall NOT contain embedded nulls. */
1285 value_from_string (char *ptr
)
1288 int len
= strlen (ptr
);
1289 int lowbound
= current_language
->string_lower_bound
;
1290 struct type
*rangetype
=
1291 create_range_type ((struct type
*) NULL
,
1293 lowbound
, len
+ lowbound
- 1);
1294 struct type
*stringtype
=
1295 create_array_type ((struct type
*) NULL
,
1296 *current_language
->string_char_type
,
1299 val
= allocate_value (stringtype
);
1300 memcpy (VALUE_CONTENTS_RAW (val
), ptr
, len
);
1305 value_from_double (struct type
*type
, DOUBLEST num
)
1307 register value_ptr val
= allocate_value (type
);
1308 struct type
*base_type
= check_typedef (type
);
1309 register enum type_code code
= TYPE_CODE (base_type
);
1310 register int len
= TYPE_LENGTH (base_type
);
1312 if (code
== TYPE_CODE_FLT
)
1314 store_typed_floating (VALUE_CONTENTS_RAW (val
), base_type
, num
);
1317 error ("Unexpected type encountered for floating constant.");
1322 /* Deal with the value that is "about to be returned". */
1324 /* Return the value that a function returning now
1325 would be returning to its caller, assuming its type is VALTYPE.
1326 RETBUF is where we look for what ought to be the contents
1327 of the registers (in raw form). This is because it is often
1328 desirable to restore old values to those registers
1329 after saving the contents of interest, and then call
1330 this function using the saved values.
1331 struct_return is non-zero when the function in question is
1332 using the structure return conventions on the machine in question;
1333 0 when it is using the value returning conventions (this often
1334 means returning pointer to where structure is vs. returning value). */
1338 value_being_returned (struct type
*valtype
, char *retbuf
, int struct_return
)
1340 register value_ptr val
;
1343 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1344 if (EXTRACT_STRUCT_VALUE_ADDRESS_P ())
1347 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1349 error ("Function return value unknown");
1350 return value_at (valtype
, addr
, NULL
);
1353 val
= allocate_value (valtype
);
1354 CHECK_TYPEDEF (valtype
);
1355 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1360 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1361 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1362 and TYPE is the type (which is known to be struct, union or array).
1364 On most machines, the struct convention is used unless we are
1365 using gcc and the type is of a special size. */
1366 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1367 native compiler. GCC 2.3.3 was the last release that did it the
1368 old way. Since gcc2_compiled was not changed, we have no
1369 way to correctly win in all cases, so we just do the right thing
1370 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1371 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1372 would cause more chaos than dealing with some struct returns being
1376 generic_use_struct_convention (int gcc_p
, struct type
*value_type
)
1378 return !((gcc_p
== 1)
1379 && (TYPE_LENGTH (value_type
) == 1
1380 || TYPE_LENGTH (value_type
) == 2
1381 || TYPE_LENGTH (value_type
) == 4
1382 || TYPE_LENGTH (value_type
) == 8));
1385 #ifndef USE_STRUCT_CONVENTION
1386 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1390 /* Return true if the function specified is using the structure returning
1391 convention on this machine to return arguments, or 0 if it is using
1392 the value returning convention. FUNCTION is the value representing
1393 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1394 is the type returned by the function. GCC_P is nonzero if compiled
1399 using_struct_return (value_ptr function
, CORE_ADDR funcaddr
,
1400 struct type
*value_type
, int gcc_p
)
1402 register enum type_code code
= TYPE_CODE (value_type
);
1404 if (code
== TYPE_CODE_ERROR
)
1405 error ("Function return type unknown.");
1407 if (code
== TYPE_CODE_STRUCT
1408 || code
== TYPE_CODE_UNION
1409 || code
== TYPE_CODE_ARRAY
1410 || RETURN_VALUE_ON_STACK (value_type
))
1411 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1416 /* Store VAL so it will be returned if a function returns now.
1417 Does not verify that VAL's type matches what the current
1418 function wants to return. */
1421 set_return_value (value_ptr val
)
1423 struct type
*type
= check_typedef (VALUE_TYPE (val
));
1424 register enum type_code code
= TYPE_CODE (type
);
1426 if (code
== TYPE_CODE_ERROR
)
1427 error ("Function return type unknown.");
1429 if (code
== TYPE_CODE_STRUCT
1430 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1431 error ("GDB does not support specifying a struct or union return value.");
1433 STORE_RETURN_VALUE (type
, VALUE_CONTENTS (val
));
1437 _initialize_values (void)
1439 add_cmd ("convenience", no_class
, show_convenience
,
1440 "Debugger convenience (\"$foo\") variables.\n\
1441 These variables are created when you assign them values;\n\
1442 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1443 A few convenience variables are given values automatically:\n\
1444 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1445 \"$__\" holds the contents of the last address examined with \"x\".",
1448 add_cmd ("values", no_class
, show_values
,
1449 "Elements of value history around item number IDX (or last ten).",