1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 87, 89, 91, 93, 94, 95, 96, 97, 1998
3 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program; if not, write to the Free Software
19 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
22 #include "gdb_string.h"
35 /* Prototypes for exported functions. */
37 void _initialize_values
PARAMS ((void));
39 /* Prototypes for local functions. */
41 static value_ptr value_headof
PARAMS ((value_ptr
, struct type
*,
44 static void show_values
PARAMS ((char *, int));
46 static void show_convenience
PARAMS ((char *, int));
48 static int vb_match
PARAMS ((struct type
*, int, struct type
*));
50 /* The value-history records all the values printed
51 by print commands during this session. Each chunk
52 records 60 consecutive values. The first chunk on
53 the chain records the most recent values.
54 The total number of values is in value_history_count. */
56 #define VALUE_HISTORY_CHUNK 60
58 struct value_history_chunk
60 struct value_history_chunk
*next
;
61 value_ptr values
[VALUE_HISTORY_CHUNK
];
64 /* Chain of chunks now in use. */
66 static struct value_history_chunk
*value_history_chain
;
68 static int value_history_count
; /* Abs number of last entry stored */
70 /* List of all value objects currently allocated
71 (except for those released by calls to release_value)
72 This is so they can be freed after each command. */
74 static value_ptr all_values
;
76 /* Allocate a value that has the correct length for type TYPE. */
82 register value_ptr val
;
83 struct type
*atype
= check_typedef (type
);
85 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (atype
));
86 VALUE_NEXT (val
) = all_values
;
88 VALUE_TYPE (val
) = type
;
89 VALUE_LVAL (val
) = not_lval
;
90 VALUE_ADDRESS (val
) = 0;
91 VALUE_FRAME (val
) = 0;
92 VALUE_OFFSET (val
) = 0;
93 VALUE_BITPOS (val
) = 0;
94 VALUE_BITSIZE (val
) = 0;
95 VALUE_REGNO (val
) = -1;
97 VALUE_OPTIMIZED_OUT (val
) = 0;
98 VALUE_BFD_SECTION (val
) = NULL
;
103 /* Allocate a value that has the correct length
104 for COUNT repetitions type TYPE. */
107 allocate_repeat_value (type
, count
)
111 int low_bound
= current_language
->string_lower_bound
; /* ??? */
112 /* FIXME-type-allocation: need a way to free this type when we are
114 struct type
*range_type
115 = create_range_type ((struct type
*) NULL
, builtin_type_int
,
116 low_bound
, count
+ low_bound
- 1);
117 /* FIXME-type-allocation: need a way to free this type when we are
119 return allocate_value (create_array_type ((struct type
*) NULL
,
123 /* Return a mark in the value chain. All values allocated after the
124 mark is obtained (except for those released) are subject to being freed
125 if a subsequent value_free_to_mark is passed the mark. */
132 /* Free all values allocated since MARK was obtained by value_mark
133 (except for those released). */
135 value_free_to_mark (mark
)
140 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
142 next
= VALUE_NEXT (val
);
148 /* Free all the values that have been allocated (except for those released).
149 Called after each command, successful or not. */
154 register value_ptr val
, next
;
156 for (val
= all_values
; val
; val
= next
)
158 next
= VALUE_NEXT (val
);
165 /* Remove VAL from the chain all_values
166 so it will not be freed automatically. */
170 register value_ptr val
;
172 register value_ptr v
;
174 if (all_values
== val
)
176 all_values
= val
->next
;
180 for (v
= all_values
; v
; v
= v
->next
)
190 /* Release all values up to mark */
192 value_release_to_mark (mark
)
197 for (val
= next
= all_values
; next
; next
= VALUE_NEXT (next
))
198 if (VALUE_NEXT (next
) == mark
)
200 all_values
= VALUE_NEXT (next
);
201 VALUE_NEXT (next
) = 0;
208 /* Return a copy of the value ARG.
209 It contains the same contents, for same memory address,
210 but it's a different block of storage. */
216 register struct type
*type
= VALUE_TYPE (arg
);
217 register value_ptr val
= allocate_value (type
);
218 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
219 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
220 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
221 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
222 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
223 VALUE_FRAME (val
) = VALUE_FRAME (arg
);
224 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
225 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
226 VALUE_OPTIMIZED_OUT (val
) = VALUE_OPTIMIZED_OUT (arg
);
227 VALUE_BFD_SECTION (val
) = VALUE_BFD_SECTION (arg
);
228 val
->modifiable
= arg
->modifiable
;
229 if (!VALUE_LAZY (val
))
231 memcpy (VALUE_CONTENTS_RAW (val
), VALUE_CONTENTS_RAW (arg
),
232 TYPE_LENGTH (VALUE_TYPE (arg
)));
237 /* Access to the value history. */
239 /* Record a new value in the value history.
240 Returns the absolute history index of the entry.
241 Result of -1 indicates the value was not saved; otherwise it is the
242 value history index of this new item. */
245 record_latest_value (val
)
250 /* We don't want this value to have anything to do with the inferior anymore.
251 In particular, "set $1 = 50" should not affect the variable from which
252 the value was taken, and fast watchpoints should be able to assume that
253 a value on the value history never changes. */
254 if (VALUE_LAZY (val
))
255 value_fetch_lazy (val
);
256 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
257 from. This is a bit dubious, because then *&$1 does not just return $1
258 but the current contents of that location. c'est la vie... */
262 /* Here we treat value_history_count as origin-zero
263 and applying to the value being stored now. */
265 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
268 register struct value_history_chunk
*new
269 = (struct value_history_chunk
*)
270 xmalloc (sizeof (struct value_history_chunk
));
271 memset (new->values
, 0, sizeof new->values
);
272 new->next
= value_history_chain
;
273 value_history_chain
= new;
276 value_history_chain
->values
[i
] = val
;
278 /* Now we regard value_history_count as origin-one
279 and applying to the value just stored. */
281 return ++value_history_count
;
284 /* Return a copy of the value in the history with sequence number NUM. */
287 access_value_history (num
)
290 register struct value_history_chunk
*chunk
;
292 register int absnum
= num
;
295 absnum
+= value_history_count
;
300 error ("The history is empty.");
302 error ("There is only one value in the history.");
304 error ("History does not go back to $$%d.", -num
);
306 if (absnum
> value_history_count
)
307 error ("History has not yet reached $%d.", absnum
);
311 /* Now absnum is always absolute and origin zero. */
313 chunk
= value_history_chain
;
314 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
318 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
321 /* Clear the value history entirely.
322 Must be done when new symbol tables are loaded,
323 because the type pointers become invalid. */
326 clear_value_history ()
328 register struct value_history_chunk
*next
;
330 register value_ptr val
;
332 while (value_history_chain
)
334 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
335 if ((val
= value_history_chain
->values
[i
]) != NULL
)
337 next
= value_history_chain
->next
;
338 free ((PTR
)value_history_chain
);
339 value_history_chain
= next
;
341 value_history_count
= 0;
345 show_values (num_exp
, from_tty
)
350 register value_ptr val
;
355 /* "info history +" should print from the stored position.
356 "info history <exp>" should print around value number <exp>. */
357 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
358 num
= parse_and_eval_address (num_exp
) - 5;
362 /* "info history" means print the last 10 values. */
363 num
= value_history_count
- 9;
369 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
371 val
= access_value_history (i
);
372 printf_filtered ("$%d = ", i
);
373 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
374 printf_filtered ("\n");
377 /* The next "info history +" should start after what we just printed. */
380 /* Hitting just return after this command should do the same thing as
381 "info history +". If num_exp is null, this is unnecessary, since
382 "info history +" is not useful after "info history". */
383 if (from_tty
&& num_exp
)
390 /* Internal variables. These are variables within the debugger
391 that hold values assigned by debugger commands.
392 The user refers to them with a '$' prefix
393 that does not appear in the variable names stored internally. */
395 static struct internalvar
*internalvars
;
397 /* Look up an internal variable with name NAME. NAME should not
398 normally include a dollar sign.
400 If the specified internal variable does not exist,
401 one is created, with a void value. */
404 lookup_internalvar (name
)
407 register struct internalvar
*var
;
409 for (var
= internalvars
; var
; var
= var
->next
)
410 if (STREQ (var
->name
, name
))
413 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
414 var
->name
= concat (name
, NULL
);
415 var
->value
= allocate_value (builtin_type_void
);
416 release_value (var
->value
);
417 var
->next
= internalvars
;
423 value_of_internalvar (var
)
424 struct internalvar
*var
;
426 register value_ptr val
;
428 #ifdef IS_TRAPPED_INTERNALVAR
429 if (IS_TRAPPED_INTERNALVAR (var
->name
))
430 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
433 val
= value_copy (var
->value
);
434 if (VALUE_LAZY (val
))
435 value_fetch_lazy (val
);
436 VALUE_LVAL (val
) = lval_internalvar
;
437 VALUE_INTERNALVAR (val
) = var
;
442 set_internalvar_component (var
, offset
, bitpos
, bitsize
, newval
)
443 struct internalvar
*var
;
444 int offset
, bitpos
, bitsize
;
447 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
449 #ifdef IS_TRAPPED_INTERNALVAR
450 if (IS_TRAPPED_INTERNALVAR (var
->name
))
451 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
455 modify_field (addr
, value_as_long (newval
),
458 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
462 set_internalvar (var
, val
)
463 struct internalvar
*var
;
468 #ifdef IS_TRAPPED_INTERNALVAR
469 if (IS_TRAPPED_INTERNALVAR (var
->name
))
470 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
473 newval
= value_copy (val
);
474 newval
->modifiable
= 1;
476 /* Force the value to be fetched from the target now, to avoid problems
477 later when this internalvar is referenced and the target is gone or
479 if (VALUE_LAZY (newval
))
480 value_fetch_lazy (newval
);
482 /* Begin code which must not call error(). If var->value points to
483 something free'd, an error() obviously leaves a dangling pointer.
484 But we also get a danling pointer if var->value points to
485 something in the value chain (i.e., before release_value is
486 called), because after the error free_all_values will get called before
488 free ((PTR
)var
->value
);
490 release_value (newval
);
491 /* End code which must not call error(). */
495 internalvar_name (var
)
496 struct internalvar
*var
;
501 /* Free all internalvars. Done when new symtabs are loaded,
502 because that makes the values invalid. */
505 clear_internalvars ()
507 register struct internalvar
*var
;
512 internalvars
= var
->next
;
513 free ((PTR
)var
->name
);
514 free ((PTR
)var
->value
);
520 show_convenience (ignore
, from_tty
)
524 register struct internalvar
*var
;
527 for (var
= internalvars
; var
; var
= var
->next
)
529 #ifdef IS_TRAPPED_INTERNALVAR
530 if (IS_TRAPPED_INTERNALVAR (var
->name
))
537 printf_filtered ("$%s = ", var
->name
);
538 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
539 printf_filtered ("\n");
542 printf_unfiltered ("No debugger convenience variables now defined.\n\
543 Convenience variables have names starting with \"$\";\n\
544 use \"set\" as in \"set $foo = 5\" to define them.\n");
547 /* Extract a value as a C number (either long or double).
548 Knows how to convert fixed values to double, or
549 floating values to long.
550 Does not deallocate the value. */
554 register value_ptr val
;
556 /* This coerces arrays and functions, which is necessary (e.g.
557 in disassemble_command). It also dereferences references, which
558 I suspect is the most logical thing to do. */
560 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
564 value_as_double (val
)
565 register value_ptr val
;
570 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
572 error ("Invalid floating value found in program.");
575 /* Extract a value as a C pointer.
576 Does not deallocate the value. */
578 value_as_pointer (val
)
581 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
582 whether we want this to be true eventually. */
584 /* ADDR_BITS_REMOVE is wrong if we are being called for a
585 non-address (e.g. argument to "signal", "info break", etc.), or
586 for pointers to char, in which the low bits *are* significant. */
587 return ADDR_BITS_REMOVE(value_as_long (val
));
589 return value_as_long (val
);
593 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
594 as a long, or as a double, assuming the raw data is described
595 by type TYPE. Knows how to convert different sizes of values
596 and can convert between fixed and floating point. We don't assume
597 any alignment for the raw data. Return value is in host byte order.
599 If you want functions and arrays to be coerced to pointers, and
600 references to be dereferenced, call value_as_long() instead.
602 C++: It is assumed that the front-end has taken care of
603 all matters concerning pointers to members. A pointer
604 to member which reaches here is considered to be equivalent
605 to an INT (or some size). After all, it is only an offset. */
608 unpack_long (type
, valaddr
)
612 register enum type_code code
= TYPE_CODE (type
);
613 register int len
= TYPE_LENGTH (type
);
614 register int nosign
= TYPE_UNSIGNED (type
);
616 if (current_language
->la_language
== language_scm
617 && is_scmvalue_type (type
))
618 return scm_unpack (type
, valaddr
, TYPE_CODE_INT
);
622 case TYPE_CODE_TYPEDEF
:
623 return unpack_long (check_typedef (type
), valaddr
);
628 case TYPE_CODE_RANGE
:
630 return extract_unsigned_integer (valaddr
, len
);
632 return extract_signed_integer (valaddr
, len
);
635 return extract_floating (valaddr
, len
);
639 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
640 whether we want this to be true eventually. */
641 #ifdef GDB_TARGET_IS_D10V
643 return D10V_MAKE_DADDR(extract_address (valaddr
, len
));
645 return extract_address (valaddr
, len
);
647 case TYPE_CODE_MEMBER
:
648 error ("not implemented: member types in unpack_long");
651 error ("Value can't be converted to integer.");
653 return 0; /* Placate lint. */
656 /* Return a double value from the specified type and address.
657 INVP points to an int which is set to 0 for valid value,
658 1 for invalid value (bad float format). In either case,
659 the returned double is OK to use. Argument is in target
660 format, result is in host format. */
663 unpack_double (type
, valaddr
, invp
)
672 *invp
= 0; /* Assume valid. */
673 CHECK_TYPEDEF (type
);
674 code
= TYPE_CODE (type
);
675 len
= TYPE_LENGTH (type
);
676 nosign
= TYPE_UNSIGNED (type
);
677 if (code
== TYPE_CODE_FLT
)
680 if (INVALID_FLOAT (valaddr
, len
))
683 return 1.234567891011121314;
686 return extract_floating (valaddr
, len
);
690 /* Unsigned -- be sure we compensate for signed LONGEST. */
691 #if !defined (_MSC_VER) || (_MSC_VER > 900)
692 return (ULONGEST
) unpack_long (type
, valaddr
);
694 /* FIXME!!! msvc22 doesn't support unsigned __int64 -> double */
695 return (LONGEST
) unpack_long (type
, valaddr
);
696 #endif /* _MSC_VER */
700 /* Signed -- we are OK with unpack_long. */
701 return unpack_long (type
, valaddr
);
705 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
706 as a CORE_ADDR, assuming the raw data is described by type TYPE.
707 We don't assume any alignment for the raw data. Return value is in
710 If you want functions and arrays to be coerced to pointers, and
711 references to be dereferenced, call value_as_pointer() instead.
713 C++: It is assumed that the front-end has taken care of
714 all matters concerning pointers to members. A pointer
715 to member which reaches here is considered to be equivalent
716 to an INT (or some size). After all, it is only an offset. */
719 unpack_pointer (type
, valaddr
)
723 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
724 whether we want this to be true eventually. */
725 return unpack_long (type
, valaddr
);
728 /* Get the value of the FIELDN'th field (which must be static) of TYPE. */
731 value_static_field (type
, fieldno
)
737 if (TYPE_FIELD_STATIC_HAS_ADDR (type
, fieldno
))
739 addr
= TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
);
744 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
745 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_NAMESPACE
, 0, NULL
);
748 addr
= SYMBOL_VALUE_ADDRESS (sym
);
749 sect
= SYMBOL_BFD_SECTION (sym
);
750 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
), addr
);
752 return value_at (TYPE_FIELD_TYPE (type
, fieldno
), addr
, sect
);
755 /* Given a value ARG1 (offset by OFFSET bytes)
756 of a struct or union type ARG_TYPE,
757 extract and return the value of one of its (non-static) fields.
758 FIELDNO says which field. */
761 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
762 register value_ptr arg1
;
764 register int fieldno
;
765 register struct type
*arg_type
;
767 register value_ptr v
;
768 register struct type
*type
;
770 CHECK_TYPEDEF (arg_type
);
771 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
773 /* Handle packed fields */
775 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
777 v
= value_from_longest (type
,
778 unpack_field_as_long (arg_type
,
779 VALUE_CONTENTS (arg1
)
782 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
783 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
787 v
= allocate_value (type
);
788 if (VALUE_LAZY (arg1
))
791 memcpy (VALUE_CONTENTS_RAW (v
),
792 VALUE_CONTENTS_RAW (arg1
) + offset
793 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8,
796 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
797 if (VALUE_LVAL (arg1
) == lval_internalvar
)
798 VALUE_LVAL (v
) = lval_internalvar_component
;
799 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
800 VALUE_OFFSET (v
) = VALUE_OFFSET (arg1
) + offset
801 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
805 /* Given a value ARG1 of a struct or union type,
806 extract and return the value of one of its (non-static) fields.
807 FIELDNO says which field. */
810 value_field (arg1
, fieldno
)
811 register value_ptr arg1
;
812 register int fieldno
;
814 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
817 /* Return a non-virtual function as a value.
818 F is the list of member functions which contains the desired method.
819 J is an index into F which provides the desired method. */
822 value_fn_field (arg1p
, f
, j
, type
, offset
)
829 register value_ptr v
;
830 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
833 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
834 0, VAR_NAMESPACE
, 0, NULL
);
838 error ("Internal error: could not find physical method named %s",
839 TYPE_FN_FIELD_PHYSNAME (f, j));
842 v
= allocate_value (ftype
);
843 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
844 VALUE_TYPE (v
) = ftype
;
848 if (type
!= VALUE_TYPE (*arg1p
))
849 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
850 value_addr (*arg1p
)));
852 /* Move the `this' pointer according to the offset.
853 VALUE_OFFSET (*arg1p) += offset;
860 /* Return a virtual function as a value.
861 ARG1 is the object which provides the virtual function
862 table pointer. *ARG1P is side-effected in calling this function.
863 F is the list of member functions which contains the desired virtual
865 J is an index into F which provides the desired virtual function.
867 TYPE is the type in which F is located. */
869 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
876 value_ptr arg1
= *arg1p
;
877 struct type
*type1
= check_typedef (VALUE_TYPE (arg1
));
878 struct type
*entry_type
;
879 /* First, get the virtual function table pointer. That comes
880 with a strange type, so cast it to type `pointer to long' (which
881 should serve just fine as a function type). Then, index into
882 the table, and convert final value to appropriate function type. */
883 value_ptr entry
, vfn
, vtbl
;
884 value_ptr vi
= value_from_longest (builtin_type_int
,
885 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
886 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
887 struct type
*context
;
888 if (fcontext
== NULL
)
889 /* We don't have an fcontext (e.g. the program was compiled with
890 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
891 This won't work right for multiple inheritance, but at least we
892 should do as well as GDB 3.x did. */
893 fcontext
= TYPE_VPTR_BASETYPE (type
);
894 context
= lookup_pointer_type (fcontext
);
895 /* Now context is a pointer to the basetype containing the vtbl. */
896 if (TYPE_TARGET_TYPE (context
) != type1
)
898 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
899 type1
= check_typedef (VALUE_TYPE (arg1
));
903 /* Now context is the basetype containing the vtbl. */
905 /* This type may have been defined before its virtual function table
906 was. If so, fill in the virtual function table entry for the
908 if (TYPE_VPTR_FIELDNO (context
) < 0)
909 fill_in_vptr_fieldno (context
);
911 /* The virtual function table is now an array of structures
912 which have the form { int16 offset, delta; void *pfn; }. */
913 vtbl
= value_ind (value_primitive_field (arg1
, 0,
914 TYPE_VPTR_FIELDNO (context
),
915 TYPE_VPTR_BASETYPE (context
)));
917 /* Index into the virtual function table. This is hard-coded because
918 looking up a field is not cheap, and it may be important to save
919 time, e.g. if the user has set a conditional breakpoint calling
920 a virtual function. */
921 entry
= value_subscript (vtbl
, vi
);
922 entry_type
= check_typedef (VALUE_TYPE (entry
));
924 if (TYPE_CODE (entry_type
) == TYPE_CODE_STRUCT
)
926 /* Move the `this' pointer according to the virtual function table. */
927 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0));
929 if (! VALUE_LAZY (arg1
))
931 VALUE_LAZY (arg1
) = 1;
932 value_fetch_lazy (arg1
);
935 vfn
= value_field (entry
, 2);
937 else if (TYPE_CODE (entry_type
) == TYPE_CODE_PTR
)
940 error ("I'm confused: virtual function table has bad type");
941 /* Reinstantiate the function pointer with the correct type. */
942 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
948 /* ARG is a pointer to an object we know to be at least
949 a DTYPE. BTYPE is the most derived basetype that has
950 already been searched (and need not be searched again).
951 After looking at the vtables between BTYPE and DTYPE,
952 return the most derived type we find. The caller must
953 be satisfied when the return value == DTYPE.
955 FIXME-tiemann: should work with dossier entries as well. */
958 value_headof (in_arg
, btype
, dtype
)
960 struct type
*btype
, *dtype
;
962 /* First collect the vtables we must look at for this object. */
963 /* FIXME-tiemann: right now, just look at top-most vtable. */
964 value_ptr arg
, vtbl
, entry
, best_entry
= 0;
966 int offset
, best_offset
= 0;
968 CORE_ADDR pc_for_sym
;
969 char *demangled_name
;
970 struct minimal_symbol
*msymbol
;
972 btype
= TYPE_VPTR_BASETYPE (dtype
);
973 CHECK_TYPEDEF (btype
);
976 arg
= value_cast (lookup_pointer_type (btype
), arg
);
977 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
979 /* Check that VTBL looks like it points to a virtual function table. */
980 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
982 || (demangled_name
= SYMBOL_NAME (msymbol
)) == NULL
983 || !VTBL_PREFIX_P (demangled_name
))
985 /* If we expected to find a vtable, but did not, let the user
986 know that we aren't happy, but don't throw an error.
987 FIXME: there has to be a better way to do this. */
988 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
989 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
990 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
991 VALUE_TYPE (in_arg
) = error_type
;
995 /* Now search through the virtual function table. */
996 entry
= value_ind (vtbl
);
997 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
998 for (i
= 1; i
<= nelems
; i
++)
1000 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
1002 /* This won't work if we're using thunks. */
1003 if (TYPE_CODE (check_typedef (VALUE_TYPE (entry
))) != TYPE_CODE_STRUCT
)
1005 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
1006 /* If we use '<=' we can handle single inheritance
1007 * where all offsets are zero - just use the first entry found. */
1008 if (offset
<= best_offset
)
1010 best_offset
= offset
;
1014 /* Move the pointer according to BEST_ENTRY's offset, and figure
1015 out what type we should return as the new pointer. */
1016 if (best_entry
== 0)
1018 /* An alternative method (which should no longer be necessary).
1019 * But we leave it in for future use, when we will hopefully
1020 * have optimizes the vtable to use thunks instead of offsets. */
1021 /* Use the name of vtable itself to extract a base type. */
1022 demangled_name
+= 4; /* Skip _vt$ prefix. */
1026 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
1027 sym
= find_pc_function (pc_for_sym
);
1028 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), DMGL_ANSI
);
1029 *(strchr (demangled_name
, ':')) = '\0';
1031 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
1033 error ("could not find type declaration for `%s'", demangled_name
);
1036 free (demangled_name
);
1037 arg
= value_add (value_cast (builtin_type_int
, arg
),
1038 value_field (best_entry
, 0));
1041 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
1045 /* ARG is a pointer object of type TYPE. If TYPE has virtual
1046 function tables, probe ARG's tables (including the vtables
1047 of its baseclasses) to figure out the most derived type that ARG
1048 could actually be a pointer to. */
1051 value_from_vtable_info (arg
, type
)
1055 /* Take care of preliminaries. */
1056 if (TYPE_VPTR_FIELDNO (type
) < 0)
1057 fill_in_vptr_fieldno (type
);
1058 if (TYPE_VPTR_FIELDNO (type
) < 0)
1061 return value_headof (arg
, 0, type
);
1064 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1065 pointer which is for the base class whose type is BASECLASS. */
1068 vb_match (type
, index
, basetype
)
1071 struct type
*basetype
;
1073 struct type
*fieldtype
;
1074 char *name
= TYPE_FIELD_NAME (type
, index
);
1075 char *field_class_name
= NULL
;
1079 /* gcc 2.4 uses _vb$. */
1080 if (name
[1] == 'v' && name
[2] == 'b' && is_cplus_marker (name
[3]))
1081 field_class_name
= name
+ 4;
1082 /* gcc 2.5 will use __vb_. */
1083 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1084 field_class_name
= name
+ 5;
1086 if (field_class_name
== NULL
)
1087 /* This field is not a virtual base class pointer. */
1090 /* It's a virtual baseclass pointer, now we just need to find out whether
1091 it is for this baseclass. */
1092 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1093 if (fieldtype
== NULL
1094 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1095 /* "Can't happen". */
1098 /* What we check for is that either the types are equal (needed for
1099 nameless types) or have the same name. This is ugly, and a more
1100 elegant solution should be devised (which would probably just push
1101 the ugliness into symbol reading unless we change the stabs format). */
1102 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1105 if (TYPE_NAME (basetype
) != NULL
1106 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1107 && STREQ (TYPE_NAME (basetype
),
1108 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1113 /* Compute the offset of the baseclass which is
1114 the INDEXth baseclass of class TYPE,
1115 for value at VALADDR (in host) at ADDRESS (in target).
1116 The result is the offset of the baseclass value relative
1117 to (the address of)(ARG) + OFFSET.
1119 -1 is returned on error. */
1122 baseclass_offset (type
, index
, valaddr
, address
)
1128 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1130 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1132 /* Must hunt for the pointer to this virtual baseclass. */
1133 register int i
, len
= TYPE_NFIELDS (type
);
1134 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1136 /* First look for the virtual baseclass pointer
1138 for (i
= n_baseclasses
; i
< len
; i
++)
1140 if (vb_match (type
, i
, basetype
))
1143 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1144 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1146 return addr
- (LONGEST
) address
;
1149 /* Not in the fields, so try looking through the baseclasses. */
1150 for (i
= index
+1; i
< n_baseclasses
; i
++)
1153 baseclass_offset (type
, i
, valaddr
, address
);
1161 /* Baseclass is easily computed. */
1162 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1165 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1168 Extracting bits depends on endianness of the machine. Compute the
1169 number of least significant bits to discard. For big endian machines,
1170 we compute the total number of bits in the anonymous object, subtract
1171 off the bit count from the MSB of the object to the MSB of the
1172 bitfield, then the size of the bitfield, which leaves the LSB discard
1173 count. For little endian machines, the discard count is simply the
1174 number of bits from the LSB of the anonymous object to the LSB of the
1177 If the field is signed, we also do sign extension. */
1180 unpack_field_as_long (type
, valaddr
, fieldno
)
1187 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1188 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1190 struct type
*field_type
;
1192 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1193 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1194 CHECK_TYPEDEF (field_type
);
1196 /* Extract bits. See comment above. */
1198 if (BITS_BIG_ENDIAN
)
1199 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1201 lsbcount
= (bitpos
% 8);
1204 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1205 If the field is signed, and is negative, then sign extend. */
1207 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
1209 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
1211 if (!TYPE_UNSIGNED (field_type
))
1213 if (val
& (valmask
^ (valmask
>> 1)))
1222 /* Modify the value of a bitfield. ADDR points to a block of memory in
1223 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1224 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1225 indicate which bits (in target bit order) comprise the bitfield. */
1228 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1231 int bitpos
, bitsize
;
1235 /* If a negative fieldval fits in the field in question, chop
1236 off the sign extension bits. */
1237 if (bitsize
< (8 * (int) sizeof (fieldval
))
1238 && (~fieldval
& ~((1 << (bitsize
- 1)) - 1)) == 0)
1239 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1241 /* Warn if value is too big to fit in the field in question. */
1242 if (bitsize
< (8 * (int) sizeof (fieldval
))
1243 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1245 /* FIXME: would like to include fieldval in the message, but
1246 we don't have a sprintf_longest. */
1247 warning ("Value does not fit in %d bits.", bitsize
);
1249 /* Truncate it, otherwise adjoining fields may be corrupted. */
1250 fieldval
= fieldval
& ((1 << bitsize
) - 1);
1253 oword
= extract_signed_integer (addr
, sizeof oword
);
1255 /* Shifting for bit field depends on endianness of the target machine. */
1256 if (BITS_BIG_ENDIAN
)
1257 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1259 /* Mask out old value, while avoiding shifts >= size of oword */
1260 if (bitsize
< 8 * (int) sizeof (oword
))
1261 oword
&= ~(((((ULONGEST
)1) << bitsize
) - 1) << bitpos
);
1263 oword
&= ~((~(ULONGEST
)0) << bitpos
);
1264 oword
|= fieldval
<< bitpos
;
1266 store_signed_integer (addr
, sizeof oword
, oword
);
1269 /* Convert C numbers into newly allocated values */
1272 value_from_longest (type
, num
)
1274 register LONGEST num
;
1276 register value_ptr val
= allocate_value (type
);
1277 register enum type_code code
;
1280 code
= TYPE_CODE (type
);
1281 len
= TYPE_LENGTH (type
);
1285 case TYPE_CODE_TYPEDEF
:
1286 type
= check_typedef (type
);
1289 case TYPE_CODE_CHAR
:
1290 case TYPE_CODE_ENUM
:
1291 case TYPE_CODE_BOOL
:
1292 case TYPE_CODE_RANGE
:
1293 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1298 /* This assumes that all pointers of a given length
1299 have the same form. */
1300 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1304 error ("Unexpected type (%d) encountered for integer constant.", code
);
1310 value_from_double (type
, num
)
1314 register value_ptr val
= allocate_value (type
);
1315 struct type
*base_type
= check_typedef (type
);
1316 register enum type_code code
= TYPE_CODE (base_type
);
1317 register int len
= TYPE_LENGTH (base_type
);
1319 if (code
== TYPE_CODE_FLT
)
1321 store_floating (VALUE_CONTENTS_RAW (val
), len
, num
);
1324 error ("Unexpected type encountered for floating constant.");
1329 /* Deal with the value that is "about to be returned". */
1331 /* Return the value that a function returning now
1332 would be returning to its caller, assuming its type is VALTYPE.
1333 RETBUF is where we look for what ought to be the contents
1334 of the registers (in raw form). This is because it is often
1335 desirable to restore old values to those registers
1336 after saving the contents of interest, and then call
1337 this function using the saved values.
1338 struct_return is non-zero when the function in question is
1339 using the structure return conventions on the machine in question;
1340 0 when it is using the value returning conventions (this often
1341 means returning pointer to where structure is vs. returning value). */
1344 value_being_returned (valtype
, retbuf
, struct_return
)
1345 register struct type
*valtype
;
1346 char retbuf
[REGISTER_BYTES
];
1350 register value_ptr val
;
1353 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1354 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1355 if (struct_return
) {
1356 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1358 error ("Function return value unknown");
1359 return value_at (valtype
, addr
, NULL
);
1363 val
= allocate_value (valtype
);
1364 CHECK_TYPEDEF (valtype
);
1365 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1370 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1371 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1372 and TYPE is the type (which is known to be struct, union or array).
1374 On most machines, the struct convention is used unless we are
1375 using gcc and the type is of a special size. */
1376 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1377 native compiler. GCC 2.3.3 was the last release that did it the
1378 old way. Since gcc2_compiled was not changed, we have no
1379 way to correctly win in all cases, so we just do the right thing
1380 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1381 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1382 would cause more chaos than dealing with some struct returns being
1386 generic_use_struct_convention (gcc_p
, value_type
)
1388 struct type
*value_type
;
1390 return !((gcc_p
== 1)
1391 && (TYPE_LENGTH (value_type
) == 1
1392 || TYPE_LENGTH (value_type
) == 2
1393 || TYPE_LENGTH (value_type
) == 4
1394 || TYPE_LENGTH (value_type
) == 8));
1397 #ifndef USE_STRUCT_CONVENTION
1398 #define USE_STRUCT_CONVENTION(gcc_p,type) generic_use_struct_convention (gcc_p, type)
1401 /* Some fundamental types (such as long double) are returned on the stack for
1402 certain architectures. This macro should return true for any type besides
1403 struct, union or array that gets returned on the stack. */
1405 #ifndef RETURN_VALUE_ON_STACK
1406 #define RETURN_VALUE_ON_STACK(TYPE) 0
1409 /* Return true if the function specified is using the structure returning
1410 convention on this machine to return arguments, or 0 if it is using
1411 the value returning convention. FUNCTION is the value representing
1412 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1413 is the type returned by the function. GCC_P is nonzero if compiled
1417 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1420 struct type
*value_type
;
1424 register enum type_code code
= TYPE_CODE (value_type
);
1426 if (code
== TYPE_CODE_ERROR
)
1427 error ("Function return type unknown.");
1429 if (code
== TYPE_CODE_STRUCT
1430 || code
== TYPE_CODE_UNION
1431 || code
== TYPE_CODE_ARRAY
1432 || RETURN_VALUE_ON_STACK (value_type
))
1433 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1438 /* Store VAL so it will be returned if a function returns now.
1439 Does not verify that VAL's type matches what the current
1440 function wants to return. */
1443 set_return_value (val
)
1446 struct type
*type
= check_typedef (VALUE_TYPE (val
));
1447 register enum type_code code
= TYPE_CODE (type
);
1449 if (code
== TYPE_CODE_ERROR
)
1450 error ("Function return type unknown.");
1452 if ( code
== TYPE_CODE_STRUCT
1453 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1454 error ("GDB does not support specifying a struct or union return value.");
1456 STORE_RETURN_VALUE (type
, VALUE_CONTENTS (val
));
1460 _initialize_values ()
1462 add_cmd ("convenience", no_class
, show_convenience
,
1463 "Debugger convenience (\"$foo\") variables.\n\
1464 These variables are created when you assign them values;\n\
1465 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1466 A few convenience variables are given values automatically:\n\
1467 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1468 \"$__\" holds the contents of the last address examined with \"x\".",
1471 add_cmd ("values", no_class
, show_values
,
1472 "Elements of value history around item number IDX (or last ten).",