1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2 Copyright 1986, 1987, 1989, 1991 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
32 /* Local function prototypes. */
34 static value_ptr value_headof
PARAMS ((value_ptr
, struct type
*,
37 static void show_values
PARAMS ((char *, int));
39 static void show_convenience
PARAMS ((char *, int));
41 /* The value-history records all the values printed
42 by print commands during this session. Each chunk
43 records 60 consecutive values. The first chunk on
44 the chain records the most recent values.
45 The total number of values is in value_history_count. */
47 #define VALUE_HISTORY_CHUNK 60
49 struct value_history_chunk
51 struct value_history_chunk
*next
;
52 value_ptr values
[VALUE_HISTORY_CHUNK
];
55 /* Chain of chunks now in use. */
57 static struct value_history_chunk
*value_history_chain
;
59 static int value_history_count
; /* Abs number of last entry stored */
61 /* List of all value objects currently allocated
62 (except for those released by calls to release_value)
63 This is so they can be freed after each command. */
65 static value_ptr all_values
;
67 /* Allocate a value that has the correct length for type TYPE. */
73 register value_ptr val
;
75 check_stub_type (type
);
77 val
= (struct value
*) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
));
78 VALUE_NEXT (val
) = all_values
;
80 VALUE_TYPE (val
) = type
;
81 VALUE_LVAL (val
) = not_lval
;
82 VALUE_ADDRESS (val
) = 0;
83 VALUE_FRAME (val
) = 0;
84 VALUE_OFFSET (val
) = 0;
85 VALUE_BITPOS (val
) = 0;
86 VALUE_BITSIZE (val
) = 0;
87 VALUE_REPEATED (val
) = 0;
88 VALUE_REPETITIONS (val
) = 0;
89 VALUE_REGNO (val
) = -1;
91 VALUE_OPTIMIZED_OUT (val
) = 0;
96 /* Allocate a value that has the correct length
97 for COUNT repetitions type TYPE. */
100 allocate_repeat_value (type
, count
)
104 register value_ptr val
;
107 (value_ptr
) xmalloc (sizeof (struct value
) + TYPE_LENGTH (type
) * count
);
108 VALUE_NEXT (val
) = all_values
;
110 VALUE_TYPE (val
) = type
;
111 VALUE_LVAL (val
) = not_lval
;
112 VALUE_ADDRESS (val
) = 0;
113 VALUE_FRAME (val
) = 0;
114 VALUE_OFFSET (val
) = 0;
115 VALUE_BITPOS (val
) = 0;
116 VALUE_BITSIZE (val
) = 0;
117 VALUE_REPEATED (val
) = 1;
118 VALUE_REPETITIONS (val
) = count
;
119 VALUE_REGNO (val
) = -1;
120 VALUE_LAZY (val
) = 0;
121 VALUE_OPTIMIZED_OUT (val
) = 0;
125 /* Return a mark in the value chain. All values allocated after the
126 mark is obtained (except for those released) are subject to being freed
127 if a subsequent value_free_to_mark is passed the mark. */
134 /* Free all values allocated since MARK was obtained by value_mark
135 (except for those released). */
137 value_free_to_mark (mark
)
142 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
144 next
= VALUE_NEXT (val
);
150 /* Free all the values that have been allocated (except for those released).
151 Called after each command, successful or not. */
156 register value_ptr val
, next
;
158 for (val
= all_values
; val
; val
= next
)
160 next
= VALUE_NEXT (val
);
167 /* Remove VAL from the chain all_values
168 so it will not be freed automatically. */
172 register value_ptr val
;
174 register value_ptr v
;
176 if (all_values
== val
)
178 all_values
= val
->next
;
182 for (v
= all_values
; v
; v
= v
->next
)
192 /* Return a copy of the value ARG.
193 It contains the same contents, for same memory address,
194 but it's a different block of storage. */
200 register value_ptr val
;
201 register struct type
*type
= VALUE_TYPE (arg
);
202 if (VALUE_REPEATED (arg
))
203 val
= allocate_repeat_value (type
, VALUE_REPETITIONS (arg
));
205 val
= allocate_value (type
);
206 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
207 VALUE_ADDRESS (val
) = VALUE_ADDRESS (arg
);
208 VALUE_OFFSET (val
) = VALUE_OFFSET (arg
);
209 VALUE_BITPOS (val
) = VALUE_BITPOS (arg
);
210 VALUE_BITSIZE (val
) = VALUE_BITSIZE (arg
);
211 VALUE_REGNO (val
) = VALUE_REGNO (arg
);
212 VALUE_LAZY (val
) = VALUE_LAZY (arg
);
213 val
->modifiable
= arg
->modifiable
;
214 if (!VALUE_LAZY (val
))
216 memcpy (VALUE_CONTENTS_RAW (val
), VALUE_CONTENTS_RAW (arg
),
217 TYPE_LENGTH (VALUE_TYPE (arg
))
218 * (VALUE_REPEATED (arg
) ? VALUE_REPETITIONS (arg
) : 1));
223 /* Access to the value history. */
225 /* Record a new value in the value history.
226 Returns the absolute history index of the entry.
227 Result of -1 indicates the value was not saved; otherwise it is the
228 value history index of this new item. */
231 record_latest_value (val
)
236 /* Check error now if about to store an invalid float. We return -1
237 to the caller, but allow them to continue, e.g. to print it as "Nan". */
238 if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_FLT
)
240 unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &i
);
241 if (i
) return -1; /* Indicate value not saved in history */
244 /* Here we treat value_history_count as origin-zero
245 and applying to the value being stored now. */
247 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
250 register struct value_history_chunk
*new
251 = (struct value_history_chunk
*)
252 xmalloc (sizeof (struct value_history_chunk
));
253 memset (new->values
, 0, sizeof new->values
);
254 new->next
= value_history_chain
;
255 value_history_chain
= new;
258 value_history_chain
->values
[i
] = val
;
260 /* We don't want this value to have anything to do with the inferior anymore.
261 In particular, "set $1 = 50" should not affect the variable from which
262 the value was taken, and fast watchpoints should be able to assume that
263 a value on the value history never changes. */
264 if (VALUE_LAZY (val
))
265 value_fetch_lazy (val
);
266 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
267 from. This is a bit dubious, because then *&$1 does not just return $1
268 but the current contents of that location. c'est la vie... */
272 /* Now we regard value_history_count as origin-one
273 and applying to the value just stored. */
275 return ++value_history_count
;
278 /* Return a copy of the value in the history with sequence number NUM. */
281 access_value_history (num
)
284 register struct value_history_chunk
*chunk
;
286 register int absnum
= num
;
289 absnum
+= value_history_count
;
294 error ("The history is empty.");
296 error ("There is only one value in the history.");
298 error ("History does not go back to $$%d.", -num
);
300 if (absnum
> value_history_count
)
301 error ("History has not yet reached $%d.", absnum
);
305 /* Now absnum is always absolute and origin zero. */
307 chunk
= value_history_chain
;
308 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
312 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
315 /* Clear the value history entirely.
316 Must be done when new symbol tables are loaded,
317 because the type pointers become invalid. */
320 clear_value_history ()
322 register struct value_history_chunk
*next
;
324 register value_ptr val
;
326 while (value_history_chain
)
328 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
329 if ((val
= value_history_chain
->values
[i
]) != NULL
)
331 next
= value_history_chain
->next
;
332 free ((PTR
)value_history_chain
);
333 value_history_chain
= next
;
335 value_history_count
= 0;
339 show_values (num_exp
, from_tty
)
344 register value_ptr val
;
349 /* "info history +" should print from the stored position.
350 "info history <exp>" should print around value number <exp>. */
351 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
352 num
= parse_and_eval_address (num_exp
) - 5;
356 /* "info history" means print the last 10 values. */
357 num
= value_history_count
- 9;
363 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
365 val
= access_value_history (i
);
366 printf_filtered ("$%d = ", i
);
367 value_print (val
, gdb_stdout
, 0, Val_pretty_default
);
368 printf_filtered ("\n");
371 /* The next "info history +" should start after what we just printed. */
374 /* Hitting just return after this command should do the same thing as
375 "info history +". If num_exp is null, this is unnecessary, since
376 "info history +" is not useful after "info history". */
377 if (from_tty
&& num_exp
)
384 /* Internal variables. These are variables within the debugger
385 that hold values assigned by debugger commands.
386 The user refers to them with a '$' prefix
387 that does not appear in the variable names stored internally. */
389 static struct internalvar
*internalvars
;
391 /* Look up an internal variable with name NAME. NAME should not
392 normally include a dollar sign.
394 If the specified internal variable does not exist,
395 one is created, with a void value. */
398 lookup_internalvar (name
)
401 register struct internalvar
*var
;
403 for (var
= internalvars
; var
; var
= var
->next
)
404 if (STREQ (var
->name
, name
))
407 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
408 var
->name
= concat (name
, NULL
);
409 var
->value
= allocate_value (builtin_type_void
);
410 release_value (var
->value
);
411 var
->next
= internalvars
;
417 value_of_internalvar (var
)
418 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 (var
, offset
, bitpos
, bitsize
, newval
)
437 struct internalvar
*var
;
438 int offset
, bitpos
, bitsize
;
441 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
443 #ifdef IS_TRAPPED_INTERNALVAR
444 if (IS_TRAPPED_INTERNALVAR (var
->name
))
445 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
449 modify_field (addr
, value_as_long (newval
),
452 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
456 set_internalvar (var
, val
)
457 struct internalvar
*var
;
460 #ifdef IS_TRAPPED_INTERNALVAR
461 if (IS_TRAPPED_INTERNALVAR (var
->name
))
462 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
465 free ((PTR
)var
->value
);
466 var
->value
= value_copy (val
);
467 /* Force the value to be fetched from the target now, to avoid problems
468 later when this internalvar is referenced and the target is gone or
470 if (VALUE_LAZY (var
->value
))
471 value_fetch_lazy (var
->value
);
472 release_value (var
->value
);
476 internalvar_name (var
)
477 struct internalvar
*var
;
482 /* Free all internalvars. Done when new symtabs are loaded,
483 because that makes the values invalid. */
486 clear_internalvars ()
488 register struct internalvar
*var
;
493 internalvars
= var
->next
;
494 free ((PTR
)var
->name
);
495 free ((PTR
)var
->value
);
501 show_convenience (ignore
, from_tty
)
505 register struct internalvar
*var
;
508 for (var
= internalvars
; var
; var
= var
->next
)
510 #ifdef IS_TRAPPED_INTERNALVAR
511 if (IS_TRAPPED_INTERNALVAR (var
->name
))
518 printf_filtered ("$%s = ", var
->name
);
519 value_print (var
->value
, gdb_stdout
, 0, Val_pretty_default
);
520 printf_filtered ("\n");
523 printf_unfiltered ("No debugger convenience variables now defined.\n\
524 Convenience variables have names starting with \"$\";\n\
525 use \"set\" as in \"set $foo = 5\" to define them.\n");
528 /* Extract a value as a C number (either long or double).
529 Knows how to convert fixed values to double, or
530 floating values to long.
531 Does not deallocate the value. */
535 register value_ptr val
;
537 /* This coerces arrays and functions, which is necessary (e.g.
538 in disassemble_command). It also dereferences references, which
539 I suspect is the most logical thing to do. */
540 if (TYPE_CODE (VALUE_TYPE (val
)) != TYPE_CODE_ENUM
)
542 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
546 value_as_double (val
)
547 register value_ptr val
;
552 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
554 error ("Invalid floating value found in program.");
557 /* Extract a value as a C pointer.
558 Does not deallocate the value. */
560 value_as_pointer (val
)
563 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
564 whether we want this to be true eventually. */
566 /* ADDR_BITS_REMOVE is wrong if we are being called for a
567 non-address (e.g. argument to "signal", "info break", etc.), or
568 for pointers to char, in which the low bits *are* significant. */
569 return ADDR_BITS_REMOVE(value_as_long (val
));
571 return value_as_long (val
);
575 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
576 as a long, or as a double, assuming the raw data is described
577 by type TYPE. Knows how to convert different sizes of values
578 and can convert between fixed and floating point. We don't assume
579 any alignment for the raw data. Return value is in host byte order.
581 If you want functions and arrays to be coerced to pointers, and
582 references to be dereferenced, call value_as_long() instead.
584 C++: It is assumed that the front-end has taken care of
585 all matters concerning pointers to members. A pointer
586 to member which reaches here is considered to be equivalent
587 to an INT (or some size). After all, it is only an offset. */
589 /* FIXME: This should be rewritten as a switch statement for speed and
590 ease of comprehension. */
593 unpack_long (type
, valaddr
)
597 register enum type_code code
= TYPE_CODE (type
);
598 register int len
= TYPE_LENGTH (type
);
599 register int nosign
= TYPE_UNSIGNED (type
);
608 return extract_unsigned_integer (valaddr
, len
);
610 return extract_signed_integer (valaddr
, len
);
613 return extract_floating (valaddr
, len
);
617 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
618 whether we want this to be true eventually. */
619 return extract_address (valaddr
, len
);
621 case TYPE_CODE_MEMBER
:
622 error ("not implemented: member types in unpack_long");
625 error ("Value can't be converted to integer.");
627 return 0; /* Placate lint. */
630 /* Return a double value from the specified type and address.
631 INVP points to an int which is set to 0 for valid value,
632 1 for invalid value (bad float format). In either case,
633 the returned double is OK to use. Argument is in target
634 format, result is in host format. */
637 unpack_double (type
, valaddr
, invp
)
642 register enum type_code code
= TYPE_CODE (type
);
643 register int len
= TYPE_LENGTH (type
);
644 register int nosign
= TYPE_UNSIGNED (type
);
646 *invp
= 0; /* Assume valid. */
647 if (code
== TYPE_CODE_FLT
)
649 if (INVALID_FLOAT (valaddr
, len
))
652 return 1.234567891011121314;
654 return extract_floating (valaddr
, len
);
658 /* Unsigned -- be sure we compensate for signed LONGEST. */
659 return (unsigned LONGEST
) unpack_long (type
, valaddr
);
663 /* Signed -- we are OK with unpack_long. */
664 return unpack_long (type
, valaddr
);
668 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
669 as a CORE_ADDR, assuming the raw data is described by type TYPE.
670 We don't assume any alignment for the raw data. Return value is in
673 If you want functions and arrays to be coerced to pointers, and
674 references to be dereferenced, call value_as_pointer() instead.
676 C++: It is assumed that the front-end has taken care of
677 all matters concerning pointers to members. A pointer
678 to member which reaches here is considered to be equivalent
679 to an INT (or some size). After all, it is only an offset. */
682 unpack_pointer (type
, valaddr
)
686 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
687 whether we want this to be true eventually. */
688 return unpack_long (type
, valaddr
);
691 /* Given a value ARG1 (offset by OFFSET bytes)
692 of a struct or union type ARG_TYPE,
693 extract and return the value of one of its fields.
694 FIELDNO says which field.
696 For C++, must also be able to return values from static fields */
699 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
700 register value_ptr arg1
;
702 register int fieldno
;
703 register struct type
*arg_type
;
705 register value_ptr v
;
706 register struct type
*type
;
708 check_stub_type (arg_type
);
709 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
711 /* Handle packed fields */
713 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
714 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
716 v
= value_from_longest (type
,
717 unpack_field_as_long (arg_type
,
718 VALUE_CONTENTS (arg1
),
720 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
721 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
725 v
= allocate_value (type
);
726 if (VALUE_LAZY (arg1
))
729 memcpy (VALUE_CONTENTS_RAW (v
), VALUE_CONTENTS_RAW (arg1
) + offset
,
732 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
733 if (VALUE_LVAL (arg1
) == lval_internalvar
)
734 VALUE_LVAL (v
) = lval_internalvar_component
;
735 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
736 VALUE_OFFSET (v
) = offset
+ VALUE_OFFSET (arg1
);
740 /* Given a value ARG1 of a struct or union type,
741 extract and return the value of one of its fields.
742 FIELDNO says which field.
744 For C++, must also be able to return values from static fields */
747 value_field (arg1
, fieldno
)
748 register value_ptr arg1
;
749 register int fieldno
;
751 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
754 /* Return a non-virtual function as a value.
755 F is the list of member functions which contains the desired method.
756 J is an index into F which provides the desired method. */
759 value_fn_field (arg1p
, f
, j
, type
, offset
)
766 register value_ptr v
;
767 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
770 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
771 0, VAR_NAMESPACE
, 0, NULL
);
775 error ("Internal error: could not find physical method named %s",
776 TYPE_FN_FIELD_PHYSNAME (f, j));
779 v
= allocate_value (ftype
);
780 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
781 VALUE_TYPE (v
) = ftype
;
785 if (type
!= VALUE_TYPE (*arg1p
))
786 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
787 value_addr (*arg1p
)));
789 /* Move the `this' pointer according to the offset.
790 VALUE_OFFSET (*arg1p) += offset;
797 /* Return a virtual function as a value.
798 ARG1 is the object which provides the virtual function
799 table pointer. *ARG1P is side-effected in calling this function.
800 F is the list of member functions which contains the desired virtual
802 J is an index into F which provides the desired virtual function.
804 TYPE is the type in which F is located. */
806 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
813 value_ptr arg1
= *arg1p
;
814 /* First, get the virtual function table pointer. That comes
815 with a strange type, so cast it to type `pointer to long' (which
816 should serve just fine as a function type). Then, index into
817 the table, and convert final value to appropriate function type. */
818 value_ptr entry
, vfn
, vtbl
;
819 value_ptr vi
= value_from_longest (builtin_type_int
,
820 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
821 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
822 struct type
*context
;
823 if (fcontext
== NULL
)
824 /* We don't have an fcontext (e.g. the program was compiled with
825 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
826 This won't work right for multiple inheritance, but at least we
827 should do as well as GDB 3.x did. */
828 fcontext
= TYPE_VPTR_BASETYPE (type
);
829 context
= lookup_pointer_type (fcontext
);
830 /* Now context is a pointer to the basetype containing the vtbl. */
831 if (TYPE_TARGET_TYPE (context
) != VALUE_TYPE (arg1
))
832 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
834 context
= VALUE_TYPE (arg1
);
835 /* Now context is the basetype containing the vtbl. */
837 /* This type may have been defined before its virtual function table
838 was. If so, fill in the virtual function table entry for the
840 if (TYPE_VPTR_FIELDNO (context
) < 0)
841 fill_in_vptr_fieldno (context
);
843 /* The virtual function table is now an array of structures
844 which have the form { int16 offset, delta; void *pfn; }. */
845 vtbl
= value_ind (value_primitive_field (arg1
, 0,
846 TYPE_VPTR_FIELDNO (context
),
847 TYPE_VPTR_BASETYPE (context
)));
849 /* Index into the virtual function table. This is hard-coded because
850 looking up a field is not cheap, and it may be important to save
851 time, e.g. if the user has set a conditional breakpoint calling
852 a virtual function. */
853 entry
= value_subscript (vtbl
, vi
);
855 /* Move the `this' pointer according to the virtual function table. */
856 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0))/* + offset*/;
858 if (! VALUE_LAZY (arg1
))
860 VALUE_LAZY (arg1
) = 1;
861 value_fetch_lazy (arg1
);
864 vfn
= value_field (entry
, 2);
865 /* Reinstantiate the function pointer with the correct type. */
866 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
872 /* ARG is a pointer to an object we know to be at least
873 a DTYPE. BTYPE is the most derived basetype that has
874 already been searched (and need not be searched again).
875 After looking at the vtables between BTYPE and DTYPE,
876 return the most derived type we find. The caller must
877 be satisfied when the return value == DTYPE.
879 FIXME-tiemann: should work with dossier entries as well. */
882 value_headof (in_arg
, btype
, dtype
)
884 struct type
*btype
, *dtype
;
886 /* First collect the vtables we must look at for this object. */
887 /* FIXME-tiemann: right now, just look at top-most vtable. */
888 value_ptr arg
, vtbl
, entry
, best_entry
= 0;
890 int offset
, best_offset
= 0;
892 CORE_ADDR pc_for_sym
;
893 char *demangled_name
;
894 struct minimal_symbol
*msymbol
;
896 btype
= TYPE_VPTR_BASETYPE (dtype
);
897 check_stub_type (btype
);
900 arg
= value_cast (lookup_pointer_type (btype
), arg
);
901 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
903 /* Check that VTBL looks like it points to a virtual function table. */
904 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
906 || !VTBL_PREFIX_P (demangled_name
= SYMBOL_NAME (msymbol
)))
908 /* If we expected to find a vtable, but did not, let the user
909 know that we aren't happy, but don't throw an error.
910 FIXME: there has to be a better way to do this. */
911 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
912 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
913 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
914 VALUE_TYPE (in_arg
) = error_type
;
918 /* Now search through the virtual function table. */
919 entry
= value_ind (vtbl
);
920 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
921 for (i
= 1; i
<= nelems
; i
++)
923 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
925 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
926 /* If we use '<=' we can handle single inheritance
927 * where all offsets are zero - just use the first entry found. */
928 if (offset
<= best_offset
)
930 best_offset
= offset
;
934 /* Move the pointer according to BEST_ENTRY's offset, and figure
935 out what type we should return as the new pointer. */
938 /* An alternative method (which should no longer be necessary).
939 * But we leave it in for future use, when we will hopefully
940 * have optimizes the vtable to use thunks instead of offsets. */
941 /* Use the name of vtable itself to extract a base type. */
942 demangled_name
+= 4; /* Skip _vt$ prefix. */
946 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
947 sym
= find_pc_function (pc_for_sym
);
948 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), DMGL_ANSI
);
949 *(strchr (demangled_name
, ':')) = '\0';
951 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
953 error ("could not find type declaration for `%s'", demangled_name
);
956 free (demangled_name
);
957 arg
= value_add (value_cast (builtin_type_int
, arg
),
958 value_field (best_entry
, 0));
961 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
965 /* ARG is a pointer object of type TYPE. If TYPE has virtual
966 function tables, probe ARG's tables (including the vtables
967 of its baseclasses) to figure out the most derived type that ARG
968 could actually be a pointer to. */
971 value_from_vtable_info (arg
, type
)
975 /* Take care of preliminaries. */
976 if (TYPE_VPTR_FIELDNO (type
) < 0)
977 fill_in_vptr_fieldno (type
);
978 if (TYPE_VPTR_FIELDNO (type
) < 0 || VALUE_REPEATED (arg
))
981 return value_headof (arg
, 0, type
);
984 /* Return true if the INDEXth field of TYPE is a virtual baseclass
985 pointer which is for the base class whose type is BASECLASS. */
988 vb_match (type
, index
, basetype
)
991 struct type
*basetype
;
993 struct type
*fieldtype
;
994 char *name
= TYPE_FIELD_NAME (type
, index
);
995 char *field_class_name
= NULL
;
999 /* gcc 2.4 uses _vb$. */
1000 if (name
[1] == 'v' && name
[2] == 'b' && name
[3] == CPLUS_MARKER
)
1001 field_class_name
= name
+ 4;
1002 /* gcc 2.5 will use __vb_. */
1003 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1004 field_class_name
= name
+ 5;
1006 if (field_class_name
== NULL
)
1007 /* This field is not a virtual base class pointer. */
1010 /* It's a virtual baseclass pointer, now we just need to find out whether
1011 it is for this baseclass. */
1012 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1013 if (fieldtype
== NULL
1014 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1015 /* "Can't happen". */
1018 /* What we check for is that either the types are equal (needed for
1019 nameless types) or have the same name. This is ugly, and a more
1020 elegant solution should be devised (which would probably just push
1021 the ugliness into symbol reading unless we change the stabs format). */
1022 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1025 if (TYPE_NAME (basetype
) != NULL
1026 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1027 && STREQ (TYPE_NAME (basetype
),
1028 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1033 /* Compute the offset of the baseclass which is
1034 the INDEXth baseclass of class TYPE, for a value ARG,
1035 wih extra offset of OFFSET.
1036 The result is the offste of the baseclass value relative
1037 to (the address of)(ARG) + OFFSET.
1039 -1 is returned on error. */
1042 baseclass_offset (type
, index
, arg
, offset
)
1048 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1050 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1052 /* Must hunt for the pointer to this virtual baseclass. */
1053 register int i
, len
= TYPE_NFIELDS (type
);
1054 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1056 /* First look for the virtual baseclass pointer
1058 for (i
= n_baseclasses
; i
< len
; i
++)
1060 if (vb_match (type
, i
, basetype
))
1063 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1064 VALUE_CONTENTS (arg
) + VALUE_OFFSET (arg
)
1066 + (TYPE_FIELD_BITPOS (type
, i
) / 8));
1068 if (VALUE_LVAL (arg
) != lval_memory
)
1072 (LONGEST
) (VALUE_ADDRESS (arg
) + VALUE_OFFSET (arg
) + offset
);
1075 /* Not in the fields, so try looking through the baseclasses. */
1076 for (i
= index
+1; i
< n_baseclasses
; i
++)
1079 baseclass_offset (type
, i
, arg
, offset
);
1087 /* Baseclass is easily computed. */
1088 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1091 /* Compute the address of the baseclass which is
1092 the INDEXth baseclass of class TYPE. The TYPE base
1093 of the object is at VALADDR.
1095 If ERRP is non-NULL, set *ERRP to be the errno code of any error,
1096 or 0 if no error. In that case the return value is not the address
1097 of the baseclasss, but the address which could not be read
1100 /* FIXME Fix remaining uses of baseclass_addr to use baseclass_offset */
1103 baseclass_addr (type
, index
, valaddr
, valuep
, errp
)
1110 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1115 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1117 /* Must hunt for the pointer to this virtual baseclass. */
1118 register int i
, len
= TYPE_NFIELDS (type
);
1119 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1121 /* First look for the virtual baseclass pointer
1123 for (i
= n_baseclasses
; i
< len
; i
++)
1125 if (vb_match (type
, i
, basetype
))
1127 value_ptr val
= allocate_value (basetype
);
1132 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1133 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1135 status
= target_read_memory (addr
,
1136 VALUE_CONTENTS_RAW (val
),
1137 TYPE_LENGTH (basetype
));
1138 VALUE_LVAL (val
) = lval_memory
;
1139 VALUE_ADDRESS (val
) = addr
;
1145 release_value (val
);
1149 return (char *)addr
;
1155 return (char *) VALUE_CONTENTS (val
);
1159 /* Not in the fields, so try looking through the baseclasses. */
1160 for (i
= index
+1; i
< n_baseclasses
; i
++)
1164 baddr
= baseclass_addr (type
, i
, valaddr
, valuep
, errp
);
1174 /* Baseclass is easily computed. */
1177 return valaddr
+ TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1180 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1183 Extracting bits depends on endianness of the machine. Compute the
1184 number of least significant bits to discard. For big endian machines,
1185 we compute the total number of bits in the anonymous object, subtract
1186 off the bit count from the MSB of the object to the MSB of the
1187 bitfield, then the size of the bitfield, which leaves the LSB discard
1188 count. For little endian machines, the discard count is simply the
1189 number of bits from the LSB of the anonymous object to the LSB of the
1192 If the field is signed, we also do sign extension. */
1195 unpack_field_as_long (type
, valaddr
, fieldno
)
1200 unsigned LONGEST val
;
1201 unsigned LONGEST valmask
;
1202 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1203 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1206 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1208 /* Extract bits. See comment above. */
1211 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1213 lsbcount
= (bitpos
% 8);
1217 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1218 If the field is signed, and is negative, then sign extend. */
1220 if ((bitsize
> 0) && (bitsize
< 8 * sizeof (val
)))
1222 valmask
= (((unsigned LONGEST
) 1) << bitsize
) - 1;
1224 if (!TYPE_UNSIGNED (TYPE_FIELD_TYPE (type
, fieldno
)))
1226 if (val
& (valmask
^ (valmask
>> 1)))
1235 /* Modify the value of a bitfield. ADDR points to a block of memory in
1236 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1237 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1238 indicate which bits (in target bit order) comprise the bitfield. */
1241 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1244 int bitpos
, bitsize
;
1248 /* Reject values too big to fit in the field in question,
1249 otherwise adjoining fields may be corrupted. */
1250 if (bitsize
< (8 * sizeof (fieldval
))
1251 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1253 /* FIXME: would like to include fieldval in the message, but
1254 we don't have a sprintf_longest. */
1255 error ("Value does not fit in %d bits.", bitsize
);
1258 oword
= extract_signed_integer (addr
, sizeof oword
);
1260 /* Shifting for bit field depends on endianness of the target machine. */
1262 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1265 /* Mask out old value, while avoiding shifts >= size of oword */
1266 if (bitsize
< 8 * sizeof (oword
))
1267 oword
&= ~(((((unsigned LONGEST
)1) << bitsize
) - 1) << bitpos
);
1269 oword
&= ~((~(unsigned LONGEST
)0) << bitpos
);
1270 oword
|= fieldval
<< bitpos
;
1272 store_signed_integer (addr
, sizeof oword
, oword
);
1275 /* Convert C numbers into newly allocated values */
1278 value_from_longest (type
, num
)
1280 register LONGEST num
;
1282 register value_ptr val
= allocate_value (type
);
1283 register enum type_code code
= TYPE_CODE (type
);
1284 register int len
= TYPE_LENGTH (type
);
1289 case TYPE_CODE_CHAR
:
1290 case TYPE_CODE_ENUM
:
1291 case TYPE_CODE_BOOL
:
1292 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1297 /* This assumes that all pointers of a given length
1298 have the same form. */
1299 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1303 error ("Unexpected type encountered for integer constant.");
1309 value_from_double (type
, num
)
1313 register value_ptr val
= allocate_value (type
);
1314 register enum type_code code
= TYPE_CODE (type
);
1315 register int len
= TYPE_LENGTH (type
);
1317 if (code
== TYPE_CODE_FLT
)
1319 store_floating (VALUE_CONTENTS_RAW (val
), len
, num
);
1322 error ("Unexpected type encountered for floating constant.");
1327 /* Deal with the value that is "about to be returned". */
1329 /* Return the value that a function returning now
1330 would be returning to its caller, assuming its type is VALTYPE.
1331 RETBUF is where we look for what ought to be the contents
1332 of the registers (in raw form). This is because it is often
1333 desirable to restore old values to those registers
1334 after saving the contents of interest, and then call
1335 this function using the saved values.
1336 struct_return is non-zero when the function in question is
1337 using the structure return conventions on the machine in question;
1338 0 when it is using the value returning conventions (this often
1339 means returning pointer to where structure is vs. returning value). */
1342 value_being_returned (valtype
, retbuf
, struct_return
)
1343 register struct type
*valtype
;
1344 char retbuf
[REGISTER_BYTES
];
1348 register value_ptr val
;
1351 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1352 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1353 if (struct_return
) {
1354 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1356 error ("Function return value unknown");
1357 return value_at (valtype
, addr
);
1361 val
= allocate_value (valtype
);
1362 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1367 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1368 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1369 and TYPE is the type (which is known to be struct, union or array).
1371 On most machines, the struct convention is used unless we are
1372 using gcc and the type is of a special size. */
1373 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1374 native compiler. GCC 2.3.3 was the last release that did it the
1375 old way. Since gcc2_compiled was not changed, we have no
1376 way to correctly win in all cases, so we just do the right thing
1377 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1378 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1379 would cause more chaos than dealing with some struct returns being
1381 #if !defined (USE_STRUCT_CONVENTION)
1382 #define USE_STRUCT_CONVENTION(gcc_p, type)\
1383 (!((gcc_p == 1) && (TYPE_LENGTH (value_type) == 1 \
1384 || TYPE_LENGTH (value_type) == 2 \
1385 || TYPE_LENGTH (value_type) == 4 \
1386 || TYPE_LENGTH (value_type) == 8 \
1391 /* Return true if the function specified is using the structure returning
1392 convention on this machine to return arguments, or 0 if it is using
1393 the value returning convention. FUNCTION is the value representing
1394 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1395 is the type returned by the function. GCC_P is nonzero if compiled
1399 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1402 struct type
*value_type
;
1406 register enum type_code code
= TYPE_CODE (value_type
);
1408 if (code
== TYPE_CODE_ERROR
)
1409 error ("Function return type unknown.");
1411 if (code
== TYPE_CODE_STRUCT
||
1412 code
== TYPE_CODE_UNION
||
1413 code
== TYPE_CODE_ARRAY
)
1414 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1419 /* Store VAL so it will be returned if a function returns now.
1420 Does not verify that VAL's type matches what the current
1421 function wants to return. */
1424 set_return_value (val
)
1427 register enum type_code code
= TYPE_CODE (VALUE_TYPE (val
));
1431 if (code
== TYPE_CODE_ERROR
)
1432 error ("Function return type unknown.");
1434 if ( code
== TYPE_CODE_STRUCT
1435 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1436 error ("GDB does not support specifying a struct or union return value.");
1438 /* FIXME, this is bogus. We don't know what the return conventions
1439 are, or how values should be promoted.... */
1440 if (code
== TYPE_CODE_FLT
)
1442 dbuf
= value_as_double (val
);
1444 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&dbuf
);
1448 lbuf
= value_as_long (val
);
1449 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&lbuf
);
1454 _initialize_values ()
1456 add_cmd ("convenience", no_class
, show_convenience
,
1457 "Debugger convenience (\"$foo\") variables.\n\
1458 These variables are created when you assign them values;\n\
1459 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1460 A few convenience variables are given values automatically:\n\
1461 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1462 \"$__\" holds the contents of the last address examined with \"x\".",
1465 add_cmd ("values", no_class
, show_values
,
1466 "Elements of value history around item number IDX (or last ten).",