1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 1987, 1989, 1991, 1993, 1994, 1995
3 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "gdb_string.h"
34 /* Local function prototypes. */
36 static value_ptr value_headof
PARAMS ((value_ptr
, struct type
*,
39 static void show_values
PARAMS ((char *, int));
41 static void show_convenience
PARAMS ((char *, int));
43 /* The value-history records all the values printed
44 by print commands during this session. Each chunk
45 records 60 consecutive values. The first chunk on
46 the chain records the most recent values.
47 The total number of values is in value_history_count. */
49 #define VALUE_HISTORY_CHUNK 60
51 struct value_history_chunk
53 struct value_history_chunk
*next
;
54 value_ptr values
[VALUE_HISTORY_CHUNK
];
57 /* Chain of chunks now in use. */
59 static struct value_history_chunk
*value_history_chain
;
61 static int value_history_count
; /* Abs number of last entry stored */
63 /* List of all value objects currently allocated
64 (except for those released by calls to release_value)
65 This is so they can be freed after each command. */
67 static value_ptr all_values
;
69 /* Allocate a value that has the correct length for type TYPE. */
75 register value_ptr val
;
77 check_stub_type (type
);
79 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
));
80 VALUE_NEXT (val
) = all_values
;
82 VALUE_TYPE (val
) = type
;
83 VALUE_LVAL (val
) = not_lval
;
84 VALUE_ADDRESS (val
) = 0;
85 VALUE_FRAME (val
) = 0;
86 VALUE_OFFSET (val
) = 0;
87 VALUE_BITPOS (val
) = 0;
88 VALUE_BITSIZE (val
) = 0;
89 VALUE_REPEATED (val
) = 0;
90 VALUE_REPETITIONS (val
) = 0;
91 VALUE_REGNO (val
) = -1;
93 VALUE_OPTIMIZED_OUT (val
) = 0;
98 /* Allocate a value that has the correct length
99 for COUNT repetitions type TYPE. */
102 allocate_repeat_value (type
, count
)
106 register value_ptr val
;
109 (value_ptr
) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
) * count
);
110 VALUE_NEXT (val
) = all_values
;
112 VALUE_TYPE (val
) = type
;
113 VALUE_LVAL (val
) = not_lval
;
114 VALUE_ADDRESS (val
) = 0;
115 VALUE_FRAME (val
) = 0;
116 VALUE_OFFSET (val
) = 0;
117 VALUE_BITPOS (val
) = 0;
118 VALUE_BITSIZE (val
) = 0;
119 VALUE_REPEATED (val
) = 1;
120 VALUE_REPETITIONS (val
) = count
;
121 VALUE_REGNO (val
) = -1;
122 VALUE_LAZY (val
) = 0;
123 VALUE_OPTIMIZED_OUT (val
) = 0;
127 /* Return a mark in the value chain. All values allocated after the
128 mark is obtained (except for those released) are subject to being freed
129 if a subsequent value_free_to_mark is passed the mark. */
136 /* Free all values allocated since MARK was obtained by value_mark
137 (except for those released). */
139 value_free_to_mark (mark
)
144 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
146 next
= VALUE_NEXT (val
);
152 /* Free all the values that have been allocated (except for those released).
153 Called after each command, successful or not. */
158 register value_ptr val
, next
;
160 for (val
= all_values
; val
; val
= next
)
162 next
= VALUE_NEXT (val
);
169 /* Remove VAL from the chain all_values
170 so it will not be freed automatically. */
174 register value_ptr val
;
176 register value_ptr v
;
178 if (all_values
== val
)
180 all_values
= val
->next
;
184 for (v
= all_values
; v
; v
= v
->next
)
194 /* Release all values up to mark */
196 value_release_to_mark (mark
)
201 for (val
= next
= all_values
; next
; next
= VALUE_NEXT (next
))
202 if (VALUE_NEXT (next
) == mark
)
204 all_values
= VALUE_NEXT (next
);
205 VALUE_NEXT (next
) = 0;
212 /* Return a copy of the value ARG.
213 It contains the same contents, for same memory address,
214 but it's a different block of storage. */
220 register value_ptr val
;
221 register struct type
*type
= VALUE_TYPE (arg
);
222 if (VALUE_REPEATED (arg
))
223 val
= allocate_repeat_value (type
, VALUE_REPETITIONS (arg
));
225 val
= allocate_value (type
);
226 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
227 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
228 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
229 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
230 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
231 VALUE_FRAME (val
) = VALUE_FRAME (arg
);
232 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
233 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
234 VALUE_OPTIMIZED_OUT (val
) = VALUE_OPTIMIZED_OUT (arg
);
235 val
->modifiable
= arg
->modifiable
;
236 if (!VALUE_LAZY (val
))
238 memcpy (VALUE_CONTENTS_RAW (val
), VALUE_CONTENTS_RAW (arg
),
239 TYPE_LENGTH (VALUE_TYPE (arg
))
240 * (VALUE_REPEATED (arg
) ? VALUE_REPETITIONS (arg
) : 1));
245 /* Access to the value history. */
247 /* Record a new value in the value history.
248 Returns the absolute history index of the entry.
249 Result of -1 indicates the value was not saved; otherwise it is the
250 value history index of this new item. */
253 record_latest_value (val
)
258 /* Check error now if about to store an invalid float. We return -1
259 to the caller, but allow them to continue, e.g. to print it as "Nan". */
260 if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_FLT
)
262 unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &i
);
263 if (i
) return -1; /* Indicate value not saved in history */
266 /* We don't want this value to have anything to do with the inferior anymore.
267 In particular, "set $1 = 50" should not affect the variable from which
268 the value was taken, and fast watchpoints should be able to assume that
269 a value on the value history never changes. */
270 if (VALUE_LAZY (val
))
271 value_fetch_lazy (val
);
272 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
273 from. This is a bit dubious, because then *&$1 does not just return $1
274 but the current contents of that location. c'est la vie... */
278 /* Here we treat value_history_count as origin-zero
279 and applying to the value being stored now. */
281 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
284 register struct value_history_chunk
*new
285 = (struct value_history_chunk
*)
286 xmalloc (sizeof (struct value_history_chunk
));
287 memset (new->values
, 0, sizeof new->values
);
288 new->next
= value_history_chain
;
289 value_history_chain
= new;
292 value_history_chain
->values
[i
] = val
;
294 /* Now we regard value_history_count as origin-one
295 and applying to the value just stored. */
297 return ++value_history_count
;
300 /* Return a copy of the value in the history with sequence number NUM. */
303 access_value_history (num
)
306 register struct value_history_chunk
*chunk
;
308 register int absnum
= num
;
311 absnum
+= value_history_count
;
316 error ("The history is empty.");
318 error ("There is only one value in the history.");
320 error ("History does not go back to $$%d.", -num
);
322 if (absnum
> value_history_count
)
323 error ("History has not yet reached $%d.", absnum
);
327 /* Now absnum is always absolute and origin zero. */
329 chunk
= value_history_chain
;
330 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
334 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
337 /* Clear the value history entirely.
338 Must be done when new symbol tables are loaded,
339 because the type pointers become invalid. */
342 clear_value_history ()
344 register struct value_history_chunk
*next
;
346 register value_ptr val
;
348 while (value_history_chain
)
350 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
351 if ((val
= value_history_chain
->values
[i
]) != NULL
)
353 next
= value_history_chain
->next
;
354 free ((PTR
)value_history_chain
);
355 value_history_chain
= next
;
357 value_history_count
= 0;
361 show_values (num_exp
, from_tty
)
366 register value_ptr val
;
371 /* "info history +" should print from the stored position.
372 "info history <exp>" should print around value number <exp>. */
373 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
374 num
= parse_and_eval_address (num_exp
) - 5;
378 /* "info history" means print the last 10 values. */
379 num
= value_history_count
- 9;
385 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
387 val
= access_value_history (i
);
388 printf_filtered ("$%d = ", i
);
389 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
390 printf_filtered ("\n");
393 /* The next "info history +" should start after what we just printed. */
396 /* Hitting just return after this command should do the same thing as
397 "info history +". If num_exp is null, this is unnecessary, since
398 "info history +" is not useful after "info history". */
399 if (from_tty
&& num_exp
)
406 /* Internal variables. These are variables within the debugger
407 that hold values assigned by debugger commands.
408 The user refers to them with a '$' prefix
409 that does not appear in the variable names stored internally. */
411 static struct internalvar
*internalvars
;
413 /* Look up an internal variable with name NAME. NAME should not
414 normally include a dollar sign.
416 If the specified internal variable does not exist,
417 one is created, with a void value. */
420 lookup_internalvar (name
)
423 register struct internalvar
*var
;
425 for (var
= internalvars
; var
; var
= var
->next
)
426 if (STREQ (var
->name
, name
))
429 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
430 var
->name
= concat (name
, NULL
);
431 var
->value
= allocate_value (builtin_type_void
);
432 release_value (var
->value
);
433 var
->next
= internalvars
;
439 value_of_internalvar (var
)
440 struct internalvar
*var
;
442 register value_ptr val
;
444 #ifdef IS_TRAPPED_INTERNALVAR
445 if (IS_TRAPPED_INTERNALVAR (var
->name
))
446 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
449 val
= value_copy (var
->value
);
450 if (VALUE_LAZY (val
))
451 value_fetch_lazy (val
);
452 VALUE_LVAL (val
) = lval_internalvar
;
453 VALUE_INTERNALVAR (val
) = var
;
458 set_internalvar_component (var
, offset
, bitpos
, bitsize
, newval
)
459 struct internalvar
*var
;
460 int offset
, bitpos
, bitsize
;
463 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
465 #ifdef IS_TRAPPED_INTERNALVAR
466 if (IS_TRAPPED_INTERNALVAR (var
->name
))
467 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
471 modify_field (addr
, value_as_long (newval
),
474 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
478 set_internalvar (var
, val
)
479 struct internalvar
*var
;
484 #ifdef IS_TRAPPED_INTERNALVAR
485 if (IS_TRAPPED_INTERNALVAR (var
->name
))
486 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
489 newval
= value_copy (val
);
490 newval
->modifiable
= 1;
492 /* Force the value to be fetched from the target now, to avoid problems
493 later when this internalvar is referenced and the target is gone or
495 if (VALUE_LAZY (newval
))
496 value_fetch_lazy (newval
);
498 /* Begin code which must not call error(). If var->value points to
499 something free'd, an error() obviously leaves a dangling pointer.
500 But we also get a danling pointer if var->value points to
501 something in the value chain (i.e., before release_value is
502 called), because after the error free_all_values will get called before
504 free ((PTR
)var
->value
);
506 release_value (newval
);
507 /* End code which must not call error(). */
511 internalvar_name (var
)
512 struct internalvar
*var
;
517 /* Free all internalvars. Done when new symtabs are loaded,
518 because that makes the values invalid. */
521 clear_internalvars ()
523 register struct internalvar
*var
;
528 internalvars
= var
->next
;
529 free ((PTR
)var
->name
);
530 free ((PTR
)var
->value
);
536 show_convenience (ignore
, from_tty
)
540 register struct internalvar
*var
;
543 for (var
= internalvars
; var
; var
= var
->next
)
545 #ifdef IS_TRAPPED_INTERNALVAR
546 if (IS_TRAPPED_INTERNALVAR (var
->name
))
553 printf_filtered ("$%s = ", var
->name
);
554 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
555 printf_filtered ("\n");
558 printf_unfiltered ("No debugger convenience variables now defined.\n\
559 Convenience variables have names starting with \"$\";\n\
560 use \"set\" as in \"set $foo = 5\" to define them.\n");
563 /* Extract a value as a C number (either long or double).
564 Knows how to convert fixed values to double, or
565 floating values to long.
566 Does not deallocate the value. */
570 register value_ptr val
;
572 /* This coerces arrays and functions, which is necessary (e.g.
573 in disassemble_command). It also dereferences references, which
574 I suspect is the most logical thing to do. */
575 if (TYPE_CODE (VALUE_TYPE (val
)) != TYPE_CODE_ENUM
)
577 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
581 value_as_double (val
)
582 register value_ptr val
;
587 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
589 error ("Invalid floating value found in program.");
592 /* Extract a value as a C pointer.
593 Does not deallocate the value. */
595 value_as_pointer (val
)
598 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
599 whether we want this to be true eventually. */
601 /* ADDR_BITS_REMOVE is wrong if we are being called for a
602 non-address (e.g. argument to "signal", "info break", etc.), or
603 for pointers to char, in which the low bits *are* significant. */
604 return ADDR_BITS_REMOVE(value_as_long (val
));
606 return value_as_long (val
);
610 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
611 as a long, or as a double, assuming the raw data is described
612 by type TYPE. Knows how to convert different sizes of values
613 and can convert between fixed and floating point. We don't assume
614 any alignment for the raw data. Return value is in host byte order.
616 If you want functions and arrays to be coerced to pointers, and
617 references to be dereferenced, call value_as_long() instead.
619 C++: It is assumed that the front-end has taken care of
620 all matters concerning pointers to members. A pointer
621 to member which reaches here is considered to be equivalent
622 to an INT (or some size). After all, it is only an offset. */
625 unpack_long (type
, valaddr
)
629 register enum type_code code
= TYPE_CODE (type
);
630 register int len
= TYPE_LENGTH (type
);
631 register int nosign
= TYPE_UNSIGNED (type
);
639 case TYPE_CODE_RANGE
:
641 return extract_unsigned_integer (valaddr
, len
);
643 return extract_signed_integer (valaddr
, len
);
646 return extract_floating (valaddr
, len
);
650 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
651 whether we want this to be true eventually. */
652 return extract_address (valaddr
, len
);
654 case TYPE_CODE_MEMBER
:
655 error ("not implemented: member types in unpack_long");
658 error ("Value can't be converted to integer.");
660 return 0; /* Placate lint. */
663 /* Return a double value from the specified type and address.
664 INVP points to an int which is set to 0 for valid value,
665 1 for invalid value (bad float format). In either case,
666 the returned double is OK to use. Argument is in target
667 format, result is in host format. */
670 unpack_double (type
, valaddr
, invp
)
675 register enum type_code code
= TYPE_CODE (type
);
676 register int len
= TYPE_LENGTH (type
);
677 register int nosign
= TYPE_UNSIGNED (type
);
679 *invp
= 0; /* Assume valid. */
680 if (code
== TYPE_CODE_FLT
)
683 if (INVALID_FLOAT (valaddr
, len
))
686 return 1.234567891011121314;
689 return extract_floating (valaddr
, len
);
693 /* Unsigned -- be sure we compensate for signed LONGEST. */
694 return (unsigned LONGEST
) unpack_long (type
, valaddr
);
698 /* Signed -- we are OK with unpack_long. */
699 return unpack_long (type
, valaddr
);
703 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
704 as a CORE_ADDR, assuming the raw data is described by type TYPE.
705 We don't assume any alignment for the raw data. Return value is in
708 If you want functions and arrays to be coerced to pointers, and
709 references to be dereferenced, call value_as_pointer() instead.
711 C++: It is assumed that the front-end has taken care of
712 all matters concerning pointers to members. A pointer
713 to member which reaches here is considered to be equivalent
714 to an INT (or some size). After all, it is only an offset. */
717 unpack_pointer (type
, 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
);
726 /* Given a value ARG1 (offset by OFFSET bytes)
727 of a struct or union type ARG_TYPE,
728 extract and return the value of one of its fields.
729 FIELDNO says which field.
731 For C++, must also be able to return values from static fields */
734 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
735 register value_ptr arg1
;
737 register int fieldno
;
738 register struct type
*arg_type
;
740 register value_ptr v
;
741 register struct type
*type
;
743 check_stub_type (arg_type
);
744 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
746 /* Handle packed fields */
748 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
749 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
751 v
= value_from_longest (type
,
752 unpack_field_as_long (arg_type
,
753 VALUE_CONTENTS (arg1
),
755 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
756 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
760 v
= allocate_value (type
);
761 if (VALUE_LAZY (arg1
))
764 memcpy (VALUE_CONTENTS_RAW (v
), VALUE_CONTENTS_RAW (arg1
) + offset
,
767 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
768 if (VALUE_LVAL (arg1
) == lval_internalvar
)
769 VALUE_LVAL (v
) = lval_internalvar_component
;
770 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
771 VALUE_OFFSET (v
) = offset
+ VALUE_OFFSET (arg1
);
775 /* Given a value ARG1 of a struct or union type,
776 extract and return the value of one of its fields.
777 FIELDNO says which field.
779 For C++, must also be able to return values from static fields */
782 value_field (arg1
, fieldno
)
783 register value_ptr arg1
;
784 register int fieldno
;
786 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
789 /* Return a non-virtual function as a value.
790 F is the list of member functions which contains the desired method.
791 J is an index into F which provides the desired method. */
794 value_fn_field (arg1p
, f
, j
, type
, offset
)
801 register value_ptr v
;
802 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
805 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
806 0, VAR_NAMESPACE
, 0, NULL
);
810 error ("Internal error: could not find physical method named %s",
811 TYPE_FN_FIELD_PHYSNAME (f, j));
814 v
= allocate_value (ftype
);
815 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
816 VALUE_TYPE (v
) = ftype
;
820 if (type
!= VALUE_TYPE (*arg1p
))
821 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
822 value_addr (*arg1p
)));
824 /* Move the `this' pointer according to the offset.
825 VALUE_OFFSET (*arg1p) += offset;
832 /* Return a virtual function as a value.
833 ARG1 is the object which provides the virtual function
834 table pointer. *ARG1P is side-effected in calling this function.
835 F is the list of member functions which contains the desired virtual
837 J is an index into F which provides the desired virtual function.
839 TYPE is the type in which F is located. */
841 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
848 value_ptr arg1
= *arg1p
;
849 /* First, get the virtual function table pointer. That comes
850 with a strange type, so cast it to type `pointer to long' (which
851 should serve just fine as a function type). Then, index into
852 the table, and convert final value to appropriate function type. */
853 value_ptr entry
, vfn
, vtbl
;
854 value_ptr vi
= value_from_longest (builtin_type_int
,
855 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
856 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
857 struct type
*context
;
858 if (fcontext
== NULL
)
859 /* We don't have an fcontext (e.g. the program was compiled with
860 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
861 This won't work right for multiple inheritance, but at least we
862 should do as well as GDB 3.x did. */
863 fcontext
= TYPE_VPTR_BASETYPE (type
);
864 context
= lookup_pointer_type (fcontext
);
865 /* Now context is a pointer to the basetype containing the vtbl. */
866 if (TYPE_TARGET_TYPE (context
) != VALUE_TYPE (arg1
))
867 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
869 context
= VALUE_TYPE (arg1
);
870 /* Now context is the basetype containing the vtbl. */
872 /* This type may have been defined before its virtual function table
873 was. If so, fill in the virtual function table entry for the
875 if (TYPE_VPTR_FIELDNO (context
) < 0)
876 fill_in_vptr_fieldno (context
);
878 /* The virtual function table is now an array of structures
879 which have the form { int16 offset, delta; void *pfn; }. */
880 vtbl
= value_ind (value_primitive_field (arg1
, 0,
881 TYPE_VPTR_FIELDNO (context
),
882 TYPE_VPTR_BASETYPE (context
)));
884 /* Index into the virtual function table. This is hard-coded because
885 looking up a field is not cheap, and it may be important to save
886 time, e.g. if the user has set a conditional breakpoint calling
887 a virtual function. */
888 entry
= value_subscript (vtbl
, vi
);
890 if (TYPE_CODE (VALUE_TYPE (entry
)) == TYPE_CODE_STRUCT
)
892 /* Move the `this' pointer according to the virtual function table. */
893 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0));
895 if (! VALUE_LAZY (arg1
))
897 VALUE_LAZY (arg1
) = 1;
898 value_fetch_lazy (arg1
);
901 vfn
= value_field (entry
, 2);
903 else if (TYPE_CODE (VALUE_TYPE (entry
)) == TYPE_CODE_PTR
)
906 error ("I'm confused: virtual function table has bad type");
907 /* Reinstantiate the function pointer with the correct type. */
908 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
914 /* ARG is a pointer to an object we know to be at least
915 a DTYPE. BTYPE is the most derived basetype that has
916 already been searched (and need not be searched again).
917 After looking at the vtables between BTYPE and DTYPE,
918 return the most derived type we find. The caller must
919 be satisfied when the return value == DTYPE.
921 FIXME-tiemann: should work with dossier entries as well. */
924 value_headof (in_arg
, btype
, dtype
)
926 struct type
*btype
, *dtype
;
928 /* First collect the vtables we must look at for this object. */
929 /* FIXME-tiemann: right now, just look at top-most vtable. */
930 value_ptr arg
, vtbl
, entry
, best_entry
= 0;
932 int offset
, best_offset
= 0;
934 CORE_ADDR pc_for_sym
;
935 char *demangled_name
;
936 struct minimal_symbol
*msymbol
;
938 btype
= TYPE_VPTR_BASETYPE (dtype
);
939 check_stub_type (btype
);
942 arg
= value_cast (lookup_pointer_type (btype
), arg
);
943 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
945 /* Check that VTBL looks like it points to a virtual function table. */
946 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
948 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
949 || !VTBL_PREFIX_P (demangled_name
))
951 /* If we expected to find a vtable, but did not, let the user
952 know that we aren't happy, but don't throw an error.
953 FIXME: there has to be a better way to do this. */
954 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
955 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
956 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
957 VALUE_TYPE (in_arg
) = error_type
;
961 /* Now search through the virtual function table. */
962 entry
= value_ind (vtbl
);
963 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
964 for (i
= 1; i
<= nelems
; i
++)
966 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
968 /* This won't work if we're using thunks. */
969 if (TYPE_CODE (VALUE_TYPE (entry
)) != TYPE_CODE_STRUCT
)
971 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
972 /* If we use '<=' we can handle single inheritance
973 * where all offsets are zero - just use the first entry found. */
974 if (offset
<= best_offset
)
976 best_offset
= offset
;
980 /* Move the pointer according to BEST_ENTRY's offset, and figure
981 out what type we should return as the new pointer. */
984 /* An alternative method (which should no longer be necessary).
985 * But we leave it in for future use, when we will hopefully
986 * have optimizes the vtable to use thunks instead of offsets. */
987 /* Use the name of vtable itself to extract a base type. */
988 demangled_name
+= 4; /* Skip _vt$ prefix. */
992 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
993 sym
= find_pc_function (pc_for_sym
);
994 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), 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 free (demangled_name
);
1003 arg
= value_add (value_cast (builtin_type_int
, arg
),
1004 value_field (best_entry
, 0));
1007 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1011 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1012 function tables, probe ARG's tables (including the vtables
1013 of its baseclasses) to figure out the most derived type that ARG
1014 could actually be a pointer to. */
1017 value_from_vtable_info (arg
, type
)
1021 /* Take care of preliminaries. */
1022 if (TYPE_VPTR_FIELDNO (type
) < 0)
1023 fill_in_vptr_fieldno (type
);
1024 if (TYPE_VPTR_FIELDNO (type
) < 0 || VALUE_REPEATED (arg
))
1027 return value_headof (arg
, 0, type
);
1030 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1031 pointer which is for the base class whose type is BASECLASS. */
1034 vb_match (type
, index
, basetype
)
1037 struct type
*basetype
;
1039 struct type
*fieldtype
;
1040 char *name
= TYPE_FIELD_NAME (type
, index
);
1041 char *field_class_name
= NULL
;
1045 /* gcc 2.4 uses _vb$. */
1046 if (name
[1] == 'v' && name
[2] == 'b' && name
[3] == CPLUS_MARKER
)
1047 field_class_name
= name
+ 4;
1048 /* gcc 2.5 will use __vb_. */
1049 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1050 field_class_name
= name
+ 5;
1052 if (field_class_name
== NULL
)
1053 /* This field is not a virtual base class pointer. */
1056 /* It's a virtual baseclass pointer, now we just need to find out whether
1057 it is for this baseclass. */
1058 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1059 if (fieldtype
== NULL
1060 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1061 /* "Can't happen". */
1064 /* What we check for is that either the types are equal (needed for
1065 nameless types) or have the same name. This is ugly, and a more
1066 elegant solution should be devised (which would probably just push
1067 the ugliness into symbol reading unless we change the stabs format). */
1068 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1071 if (TYPE_NAME (basetype
) != NULL
1072 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1073 && STREQ (TYPE_NAME (basetype
),
1074 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1079 /* Compute the offset of the baseclass which is
1080 the INDEXth baseclass of class TYPE, for a value ARG,
1081 wih extra offset of OFFSET.
1082 The result is the offste of the baseclass value relative
1083 to (the address of)(ARG) + OFFSET.
1085 -1 is returned on error. */
1088 baseclass_offset (type
, index
, arg
, offset
)
1094 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1096 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1098 /* Must hunt for the pointer to this virtual baseclass. */
1099 register int i
, len
= TYPE_NFIELDS (type
);
1100 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1102 /* First look for the virtual baseclass pointer
1104 for (i
= n_baseclasses
; i
< len
; i
++)
1106 if (vb_match (type
, i
, basetype
))
1109 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1110 VALUE_CONTENTS (arg
) + VALUE_OFFSET (arg
)
1112 + (TYPE_FIELD_BITPOS (type
, i
) / 8));
1114 if (VALUE_LVAL (arg
) != lval_memory
)
1118 (LONGEST
) (VALUE_ADDRESS (arg
) + VALUE_OFFSET (arg
) + offset
);
1121 /* Not in the fields, so try looking through the baseclasses. */
1122 for (i
= index
+1; i
< n_baseclasses
; i
++)
1125 baseclass_offset (type
, i
, arg
, offset
);
1133 /* Baseclass is easily computed. */
1134 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1137 /* Compute the address of the baseclass which is
1138 the INDEXth baseclass of class TYPE. The TYPE base
1139 of the object is at VALADDR.
1141 If ERRP is non-NULL, set *ERRP to be the errno code of any error,
1142 or 0 if no error. In that case the return value is not the address
1143 of the baseclasss, but the address which could not be read
1146 /* FIXME Fix remaining uses of baseclass_addr to use baseclass_offset */
1149 baseclass_addr (type
, index
, valaddr
, valuep
, errp
)
1156 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1161 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1163 /* Must hunt for the pointer to this virtual baseclass. */
1164 register int i
, len
= TYPE_NFIELDS (type
);
1165 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1167 /* First look for the virtual baseclass pointer
1169 for (i
= n_baseclasses
; i
< len
; i
++)
1171 if (vb_match (type
, i
, basetype
))
1173 value_ptr val
= allocate_value (basetype
);
1178 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1179 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1181 status
= target_read_memory (addr
,
1182 VALUE_CONTENTS_RAW (val
),
1183 TYPE_LENGTH (basetype
));
1184 VALUE_LVAL (val
) = lval_memory
;
1185 VALUE_ADDRESS (val
) = addr
;
1191 release_value (val
);
1195 return (char *)addr
;
1201 return (char *) VALUE_CONTENTS (val
);
1205 /* Not in the fields, so try looking through the baseclasses. */
1206 for (i
= index
+1; i
< n_baseclasses
; i
++)
1210 baddr
= baseclass_addr (type
, i
, valaddr
, valuep
, errp
);
1220 /* Baseclass is easily computed. */
1223 return valaddr
+ TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1226 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1229 Extracting bits depends on endianness of the machine. Compute the
1230 number of least significant bits to discard. For big endian machines,
1231 we compute the total number of bits in the anonymous object, subtract
1232 off the bit count from the MSB of the object to the MSB of the
1233 bitfield, then the size of the bitfield, which leaves the LSB discard
1234 count. For little endian machines, the discard count is simply the
1235 number of bits from the LSB of the anonymous object to the LSB of the
1238 If the field is signed, we also do sign extension. */
1241 unpack_field_as_long (type
, valaddr
, fieldno
)
1246 unsigned LONGEST val
;
1247 unsigned LONGEST valmask
;
1248 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1249 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1252 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1254 /* Extract bits. See comment above. */
1256 if (BITS_BIG_ENDIAN
)
1257 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1259 lsbcount
= (bitpos
% 8);
1262 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1263 If the field is signed, and is negative, then sign extend. */
1265 if ((bitsize
> 0) && (bitsize
< 8 * sizeof (val
)))
1267 valmask
= (((unsigned LONGEST
) 1) << bitsize
) - 1;
1269 if (!TYPE_UNSIGNED (TYPE_FIELD_TYPE (type
, fieldno
)))
1271 if (val
& (valmask
^ (valmask
>> 1)))
1280 /* Modify the value of a bitfield. ADDR points to a block of memory in
1281 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1282 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1283 indicate which bits (in target bit order) comprise the bitfield. */
1286 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1289 int bitpos
, bitsize
;
1293 /* If a negative fieldval fits in the field in question, chop
1294 off the sign extension bits. */
1295 if (bitsize
< (8 * sizeof (fieldval
))
1296 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1297 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1299 /* Warn if value is too big to fit in the field in question. */
1300 if (bitsize
< (8 * sizeof (fieldval
))
1301 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1303 /* FIXME: would like to include fieldval in the message, but
1304 we don't have a sprintf_longest. */
1305 warning ("Value does not fit in %d bits.", bitsize
);
1307 /* Truncate it, otherwise adjoining fields may be corrupted. */
1308 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1311 oword
= extract_signed_integer (addr
, sizeof oword
);
1313 /* Shifting for bit field depends on endianness of the target machine. */
1314 if (BITS_BIG_ENDIAN
)
1315 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1317 /* Mask out old value, while avoiding shifts >= size of oword */
1318 if (bitsize
< 8 * sizeof (oword
))
1319 oword
&= ~(((((unsigned LONGEST
)1) << bitsize
) - 1) << bitpos
);
1321 oword
&= ~((~(unsigned LONGEST
)0) << bitpos
);
1322 oword
|= fieldval
<< bitpos
;
1324 store_signed_integer (addr
, sizeof oword
, oword
);
1327 /* Convert C numbers into newly allocated values */
1330 value_from_longest (type
, num
)
1332 register LONGEST num
;
1334 register value_ptr val
= allocate_value (type
);
1335 register enum type_code code
= TYPE_CODE (type
);
1336 register int len
= TYPE_LENGTH (type
);
1341 case TYPE_CODE_CHAR
:
1342 case TYPE_CODE_ENUM
:
1343 case TYPE_CODE_BOOL
:
1344 case TYPE_CODE_RANGE
:
1345 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1350 /* This assumes that all pointers of a given length
1351 have the same form. */
1352 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1356 error ("Unexpected type encountered for integer constant.");
1362 value_from_double (type
, num
)
1366 register value_ptr val
= allocate_value (type
);
1367 register enum type_code code
= TYPE_CODE (type
);
1368 register int len
= TYPE_LENGTH (type
);
1370 if (code
== TYPE_CODE_FLT
)
1372 store_floating (VALUE_CONTENTS_RAW (val
), len
, num
);
1375 error ("Unexpected type encountered for floating constant.");
1380 /* Deal with the value that is "about to be returned". */
1382 /* Return the value that a function returning now
1383 would be returning to its caller, assuming its type is VALTYPE.
1384 RETBUF is where we look for what ought to be the contents
1385 of the registers (in raw form). This is because it is often
1386 desirable to restore old values to those registers
1387 after saving the contents of interest, and then call
1388 this function using the saved values.
1389 struct_return is non-zero when the function in question is
1390 using the structure return conventions on the machine in question;
1391 0 when it is using the value returning conventions (this often
1392 means returning pointer to where structure is vs. returning value). */
1395 value_being_returned (valtype
, retbuf
, struct_return
)
1396 register struct type
*valtype
;
1397 char retbuf
[REGISTER_BYTES
];
1401 register value_ptr val
;
1404 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1405 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1406 if (struct_return
) {
1407 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1409 error ("Function return value unknown");
1410 return value_at (valtype
, addr
);
1414 val
= allocate_value (valtype
);
1415 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1420 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1421 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1422 and TYPE is the type (which is known to be struct, union or array).
1424 On most machines, the struct convention is used unless we are
1425 using gcc and the type is of a special size. */
1426 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1427 native compiler. GCC 2.3.3 was the last release that did it the
1428 old way. Since gcc2_compiled was not changed, we have no
1429 way to correctly win in all cases, so we just do the right thing
1430 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1431 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1432 would cause more chaos than dealing with some struct returns being
1434 #if !defined (USE_STRUCT_CONVENTION)
1435 #define USE_STRUCT_CONVENTION(gcc_p, type)\
1436 (!((gcc_p == 1) && (TYPE_LENGTH (value_type) == 1 \
1437 || TYPE_LENGTH (value_type) == 2 \
1438 || TYPE_LENGTH (value_type) == 4 \
1439 || TYPE_LENGTH (value_type) == 8 \
1444 /* Return true if the function specified is using the structure returning
1445 convention on this machine to return arguments, or 0 if it is using
1446 the value returning convention. FUNCTION is the value representing
1447 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1448 is the type returned by the function. GCC_P is nonzero if compiled
1452 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1455 struct type
*value_type
;
1459 register enum type_code code
= TYPE_CODE (value_type
);
1461 if (code
== TYPE_CODE_ERROR
)
1462 error ("Function return type unknown.");
1464 if (code
== TYPE_CODE_STRUCT
||
1465 code
== TYPE_CODE_UNION
||
1466 code
== TYPE_CODE_ARRAY
)
1467 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1472 /* Store VAL so it will be returned if a function returns now.
1473 Does not verify that VAL's type matches what the current
1474 function wants to return. */
1477 set_return_value (val
)
1480 register enum type_code code
= TYPE_CODE (VALUE_TYPE (val
));
1482 if (code
== TYPE_CODE_ERROR
)
1483 error ("Function return type unknown.");
1485 if ( code
== TYPE_CODE_STRUCT
1486 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1487 error ("GDB does not support specifying a struct or union return value.");
1489 STORE_RETURN_VALUE (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
1493 _initialize_values ()
1495 add_cmd ("convenience", no_class
, show_convenience
,
1496 "Debugger convenience (\"$foo\") variables.\n\
1497 These variables are created when you assign them values;\n\
1498 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1499 A few convenience variables are given values automatically:\n\
1500 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1501 \"$__\" holds the contents of the last address examined with \"x\".",
1504 add_cmd ("values", no_class
, show_values
,
1505 "Elements of value history around item number IDX (or last ten).",