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. */
35 value_headof
PARAMS ((value
, struct type
*, struct type
*));
38 show_values
PARAMS ((char *, int));
41 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 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 all_values
;
69 /* Allocate a value that has the correct length for type TYPE. */
77 check_stub_type (type
);
79 val
= (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;
97 /* Allocate a value that has the correct length
98 for COUNT repetitions type TYPE. */
101 allocate_repeat_value (type
, count
)
107 val
= (value
) 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 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. */
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. */
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 if (!VALUE_LAZY (val
))
215 memcpy (VALUE_CONTENTS_RAW (val
), VALUE_CONTENTS_RAW (arg
),
216 TYPE_LENGTH (VALUE_TYPE (arg
))
217 * (VALUE_REPEATED (arg
) ? VALUE_REPETITIONS (arg
) : 1));
222 /* Access to the value history. */
224 /* Record a new value in the value history.
225 Returns the absolute history index of the entry.
226 Result of -1 indicates the value was not saved; otherwise it is the
227 value history index of this new item. */
230 record_latest_value (val
)
235 /* Check error now if about to store an invalid float. We return -1
236 to the caller, but allow them to continue, e.g. to print it as "Nan". */
237 if (TYPE_CODE (VALUE_TYPE (val
)) == TYPE_CODE_FLT
)
239 unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &i
);
240 if (i
) return -1; /* Indicate value not saved in history */
243 /* Here we treat value_history_count as origin-zero
244 and applying to the value being stored now. */
246 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
249 register struct value_history_chunk
*new
250 = (struct value_history_chunk
*)
251 xmalloc (sizeof (struct value_history_chunk
));
252 memset (new->values
, 0, sizeof new->values
);
253 new->next
= value_history_chain
;
254 value_history_chain
= new;
257 value_history_chain
->values
[i
] = val
;
260 /* Now we regard value_history_count as origin-one
261 and applying to the value just stored. */
263 return ++value_history_count
;
266 /* Return a copy of the value in the history with sequence number NUM. */
269 access_value_history (num
)
272 register struct value_history_chunk
*chunk
;
274 register int absnum
= num
;
277 absnum
+= value_history_count
;
282 error ("The history is empty.");
284 error ("There is only one value in the history.");
286 error ("History does not go back to $$%d.", -num
);
288 if (absnum
> value_history_count
)
289 error ("History has not yet reached $%d.", absnum
);
293 /* Now absnum is always absolute and origin zero. */
295 chunk
= value_history_chain
;
296 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
300 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
303 /* Clear the value history entirely.
304 Must be done when new symbol tables are loaded,
305 because the type pointers become invalid. */
308 clear_value_history ()
310 register struct value_history_chunk
*next
;
314 while (value_history_chain
)
316 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
317 if ((val
= value_history_chain
->values
[i
]) != NULL
)
319 next
= value_history_chain
->next
;
320 free ((PTR
)value_history_chain
);
321 value_history_chain
= next
;
323 value_history_count
= 0;
327 show_values (num_exp
, from_tty
)
337 if (num_exp
[0] == '+' && num_exp
[1] == '\0')
338 /* "info history +" should print from the stored position. */
341 /* "info history <exp>" should print around value number <exp>. */
342 num
= parse_and_eval_address (num_exp
) - 5;
346 /* "info history" means print the last 10 values. */
347 num
= value_history_count
- 9;
353 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
355 val
= access_value_history (i
);
356 printf_filtered ("$%d = ", i
);
357 value_print (val
, stdout
, 0, Val_pretty_default
);
358 printf_filtered ("\n");
361 /* The next "info history +" should start after what we just printed. */
364 /* Hitting just return after this command should do the same thing as
365 "info history +". If num_exp is null, this is unnecessary, since
366 "info history +" is not useful after "info history". */
367 if (from_tty
&& num_exp
)
374 /* Internal variables. These are variables within the debugger
375 that hold values assigned by debugger commands.
376 The user refers to them with a '$' prefix
377 that does not appear in the variable names stored internally. */
379 static struct internalvar
*internalvars
;
381 /* Look up an internal variable with name NAME. NAME should not
382 normally include a dollar sign.
384 If the specified internal variable does not exist,
385 one is created, with a void value. */
388 lookup_internalvar (name
)
391 register struct internalvar
*var
;
393 for (var
= internalvars
; var
; var
= var
->next
)
394 if (STREQ (var
->name
, name
))
397 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
398 var
->name
= concat (name
, NULL
);
399 var
->value
= allocate_value (builtin_type_void
);
400 release_value (var
->value
);
401 var
->next
= internalvars
;
407 value_of_internalvar (var
)
408 struct internalvar
*var
;
412 #ifdef IS_TRAPPED_INTERNALVAR
413 if (IS_TRAPPED_INTERNALVAR (var
->name
))
414 return VALUE_OF_TRAPPED_INTERNALVAR (var
);
417 val
= value_copy (var
->value
);
418 if (VALUE_LAZY (val
))
419 value_fetch_lazy (val
);
420 VALUE_LVAL (val
) = lval_internalvar
;
421 VALUE_INTERNALVAR (val
) = var
;
426 set_internalvar_component (var
, offset
, bitpos
, bitsize
, newval
)
427 struct internalvar
*var
;
428 int offset
, bitpos
, bitsize
;
431 register char *addr
= VALUE_CONTENTS (var
->value
) + offset
;
433 #ifdef IS_TRAPPED_INTERNALVAR
434 if (IS_TRAPPED_INTERNALVAR (var
->name
))
435 SET_TRAPPED_INTERNALVAR (var
, newval
, bitpos
, bitsize
, offset
);
439 modify_field (addr
, value_as_long (newval
),
442 memcpy (addr
, VALUE_CONTENTS (newval
), TYPE_LENGTH (VALUE_TYPE (newval
)));
446 set_internalvar (var
, val
)
447 struct internalvar
*var
;
450 #ifdef IS_TRAPPED_INTERNALVAR
451 if (IS_TRAPPED_INTERNALVAR (var
->name
))
452 SET_TRAPPED_INTERNALVAR (var
, val
, 0, 0, 0);
455 free ((PTR
)var
->value
);
456 var
->value
= value_copy (val
);
457 /* Force the value to be fetched from the target now, to avoid problems
458 later when this internalvar is referenced and the target is gone or
460 if (VALUE_LAZY (var
->value
))
461 value_fetch_lazy (var
->value
);
462 release_value (var
->value
);
466 internalvar_name (var
)
467 struct internalvar
*var
;
472 /* Free all internalvars. Done when new symtabs are loaded,
473 because that makes the values invalid. */
476 clear_internalvars ()
478 register struct internalvar
*var
;
483 internalvars
= var
->next
;
484 free ((PTR
)var
->name
);
485 free ((PTR
)var
->value
);
491 show_convenience (ignore
, from_tty
)
495 register struct internalvar
*var
;
498 for (var
= internalvars
; var
; var
= var
->next
)
500 #ifdef IS_TRAPPED_INTERNALVAR
501 if (IS_TRAPPED_INTERNALVAR (var
->name
))
508 printf_filtered ("$%s = ", var
->name
);
509 value_print (var
->value
, stdout
, 0, Val_pretty_default
);
510 printf_filtered ("\n");
513 printf ("No debugger convenience variables now defined.\n\
514 Convenience variables have names starting with \"$\";\n\
515 use \"set\" as in \"set $foo = 5\" to define them.\n");
518 /* Extract a value as a C number (either long or double).
519 Knows how to convert fixed values to double, or
520 floating values to long.
521 Does not deallocate the value. */
527 /* This coerces arrays and functions, which is necessary (e.g.
528 in disassemble_command). It also dereferences references, which
529 I suspect is the most logical thing to do. */
530 if (TYPE_CODE (VALUE_TYPE (val
)) != TYPE_CODE_ENUM
)
532 return unpack_long (VALUE_TYPE (val
), VALUE_CONTENTS (val
));
536 value_as_double (val
)
542 foo
= unpack_double (VALUE_TYPE (val
), VALUE_CONTENTS (val
), &inv
);
544 error ("Invalid floating value found in program.");
547 /* Extract a value as a C pointer.
548 Does not deallocate the value. */
550 value_as_pointer (val
)
553 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
554 whether we want this to be true eventually. */
555 return ADDR_BITS_REMOVE(value_as_long (val
));
558 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
559 as a long, or as a double, assuming the raw data is described
560 by type TYPE. Knows how to convert different sizes of values
561 and can convert between fixed and floating point. We don't assume
562 any alignment for the raw data. Return value is in host byte order.
564 If you want functions and arrays to be coerced to pointers, and
565 references to be dereferenced, call value_as_long() instead.
567 C++: It is assumed that the front-end has taken care of
568 all matters concerning pointers to members. A pointer
569 to member which reaches here is considered to be equivalent
570 to an INT (or some size). After all, it is only an offset. */
572 /* FIXME: This should be rewritten as a switch statement for speed and
573 ease of comprehension. */
576 unpack_long (type
, valaddr
)
580 register enum type_code code
= TYPE_CODE (type
);
581 register int len
= TYPE_LENGTH (type
);
582 register int nosign
= TYPE_UNSIGNED (type
);
584 if (code
== TYPE_CODE_ENUM
|| code
== TYPE_CODE_BOOL
)
585 code
= TYPE_CODE_INT
;
586 if (code
== TYPE_CODE_FLT
)
588 if (len
== sizeof (float))
591 memcpy (&retval
, valaddr
, sizeof (retval
));
592 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
596 if (len
== sizeof (double))
599 memcpy (&retval
, valaddr
, sizeof (retval
));
600 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
605 error ("Unexpected type of floating point number.");
608 else if ((code
== TYPE_CODE_INT
|| code
== TYPE_CODE_CHAR
) && nosign
)
610 return extract_unsigned_integer (valaddr
, len
);
612 else if (code
== TYPE_CODE_INT
|| code
== TYPE_CODE_CHAR
)
614 return extract_signed_integer (valaddr
, len
);
616 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
617 whether we want this to be true eventually. */
618 else if (code
== TYPE_CODE_PTR
|| code
== TYPE_CODE_REF
)
620 return extract_address (valaddr
, len
);
622 else if (code
== TYPE_CODE_MEMBER
)
623 error ("not implemented: member types in unpack_long");
625 error ("Value not integer or pointer.");
626 return 0; /* For lint -- never reached */
629 /* Return a double value from the specified type and address.
630 INVP points to an int which is set to 0 for valid value,
631 1 for invalid value (bad float format). In either case,
632 the returned double is OK to use. Argument is in target
633 format, result is in host format. */
636 unpack_double (type
, valaddr
, invp
)
641 register enum type_code code
= TYPE_CODE (type
);
642 register int len
= TYPE_LENGTH (type
);
643 register int nosign
= TYPE_UNSIGNED (type
);
645 *invp
= 0; /* Assume valid. */
646 if (code
== TYPE_CODE_FLT
)
648 if (INVALID_FLOAT (valaddr
, len
))
651 return 1.234567891011121314;
654 if (len
== sizeof (float))
657 memcpy (&retval
, valaddr
, sizeof (retval
));
658 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
662 if (len
== sizeof (double))
665 memcpy (&retval
, valaddr
, sizeof (retval
));
666 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
671 error ("Unexpected type of floating point number.");
672 return 0; /* Placate lint. */
676 /* Unsigned -- be sure we compensate for signed LONGEST. */
677 return (unsigned LONGEST
) unpack_long (type
, valaddr
);
679 /* Signed -- we are OK with unpack_long. */
680 return unpack_long (type
, valaddr
);
684 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
685 as a CORE_ADDR, assuming the raw data is described by type TYPE.
686 We don't assume any alignment for the raw data. Return value is in
689 If you want functions and arrays to be coerced to pointers, and
690 references to be dereferenced, call value_as_pointer() instead.
692 C++: It is assumed that the front-end has taken care of
693 all matters concerning pointers to members. A pointer
694 to member which reaches here is considered to be equivalent
695 to an INT (or some size). After all, it is only an offset. */
698 unpack_pointer (type
, valaddr
)
702 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
703 whether we want this to be true eventually. */
704 return unpack_long (type
, valaddr
);
707 /* Given a value ARG1 (offset by OFFSET bytes)
708 of a struct or union type ARG_TYPE,
709 extract and return the value of one of its fields.
710 FIELDNO says which field.
712 For C++, must also be able to return values from static fields */
715 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
718 register int fieldno
;
719 register struct type
*arg_type
;
722 register struct type
*type
;
724 check_stub_type (arg_type
);
725 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
727 /* Handle packed fields */
729 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
730 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
732 v
= value_from_longest (type
,
733 unpack_field_as_long (arg_type
,
734 VALUE_CONTENTS (arg1
),
736 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
737 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
741 v
= allocate_value (type
);
742 if (VALUE_LAZY (arg1
))
745 memcpy (VALUE_CONTENTS_RAW (v
), VALUE_CONTENTS_RAW (arg1
) + offset
,
748 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
749 if (VALUE_LVAL (arg1
) == lval_internalvar
)
750 VALUE_LVAL (v
) = lval_internalvar_component
;
751 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
752 VALUE_OFFSET (v
) = offset
+ VALUE_OFFSET (arg1
);
756 /* Given a value ARG1 of a struct or union type,
757 extract and return the value of one of its fields.
758 FIELDNO says which field.
760 For C++, must also be able to return values from static fields */
763 value_field (arg1
, fieldno
)
765 register int fieldno
;
767 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
770 /* Return a non-virtual function as a value.
771 F is the list of member functions which contains the desired method.
772 J is an index into F which provides the desired method. */
775 value_fn_field (arg1p
, f
, j
, type
, offset
)
783 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
786 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
787 0, VAR_NAMESPACE
, 0, NULL
);
788 if (! sym
) error ("Internal error: could not find physical method named %s",
789 TYPE_FN_FIELD_PHYSNAME (f
, j
));
791 v
= allocate_value (ftype
);
792 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
793 VALUE_TYPE (v
) = ftype
;
797 if (type
!= VALUE_TYPE (*arg1p
))
798 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
799 value_addr (*arg1p
)));
801 /* Move the `this' pointer according to the offset. */
802 VALUE_OFFSET (*arg1p
) += offset
;
808 /* Return a virtual function as a value.
809 ARG1 is the object which provides the virtual function
810 table pointer. *ARG1P is side-effected in calling this function.
811 F is the list of member functions which contains the desired virtual
813 J is an index into F which provides the desired virtual function.
815 TYPE is the type in which F is located. */
817 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
825 /* First, get the virtual function table pointer. That comes
826 with a strange type, so cast it to type `pointer to long' (which
827 should serve just fine as a function type). Then, index into
828 the table, and convert final value to appropriate function type. */
829 value entry
, vfn
, vtbl
;
830 value vi
= value_from_longest (builtin_type_int
,
831 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
832 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
833 struct type
*context
;
834 if (fcontext
== NULL
)
835 /* We don't have an fcontext (e.g. the program was compiled with
836 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
837 This won't work right for multiple inheritance, but at least we
838 should do as well as GDB 3.x did. */
839 fcontext
= TYPE_VPTR_BASETYPE (type
);
840 context
= lookup_pointer_type (fcontext
);
841 /* Now context is a pointer to the basetype containing the vtbl. */
842 if (TYPE_TARGET_TYPE (context
) != VALUE_TYPE (arg1
))
843 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
845 context
= VALUE_TYPE (arg1
);
846 /* Now context is the basetype containing the vtbl. */
848 /* This type may have been defined before its virtual function table
849 was. If so, fill in the virtual function table entry for the
851 if (TYPE_VPTR_FIELDNO (context
) < 0)
852 fill_in_vptr_fieldno (context
);
854 /* The virtual function table is now an array of structures
855 which have the form { int16 offset, delta; void *pfn; }. */
856 vtbl
= value_ind (value_primitive_field (arg1
, 0,
857 TYPE_VPTR_FIELDNO (context
),
858 TYPE_VPTR_BASETYPE (context
)));
860 /* Index into the virtual function table. This is hard-coded because
861 looking up a field is not cheap, and it may be important to save
862 time, e.g. if the user has set a conditional breakpoint calling
863 a virtual function. */
864 entry
= value_subscript (vtbl
, vi
);
866 /* Move the `this' pointer according to the virtual function table. */
867 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0)) + offset
;
868 if (! VALUE_LAZY (arg1
))
870 VALUE_LAZY (arg1
) = 1;
871 value_fetch_lazy (arg1
);
874 vfn
= value_field (entry
, 2);
875 /* Reinstantiate the function pointer with the correct type. */
876 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
882 /* ARG is a pointer to an object we know to be at least
883 a DTYPE. BTYPE is the most derived basetype that has
884 already been searched (and need not be searched again).
885 After looking at the vtables between BTYPE and DTYPE,
886 return the most derived type we find. The caller must
887 be satisfied when the return value == DTYPE.
889 FIXME-tiemann: should work with dossier entries as well. */
892 value_headof (in_arg
, btype
, dtype
)
894 struct type
*btype
, *dtype
;
896 /* First collect the vtables we must look at for this object. */
897 /* FIXME-tiemann: right now, just look at top-most vtable. */
898 value arg
, vtbl
, entry
, best_entry
= 0;
900 int offset
, best_offset
= 0;
902 CORE_ADDR pc_for_sym
;
903 char *demangled_name
;
904 struct minimal_symbol
*msymbol
;
906 btype
= TYPE_VPTR_BASETYPE (dtype
);
907 check_stub_type (btype
);
910 arg
= value_cast (lookup_pointer_type (btype
), arg
);
911 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
913 /* Check that VTBL looks like it points to a virtual function table. */
914 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
916 || !VTBL_PREFIX_P (demangled_name
= SYMBOL_NAME (msymbol
)))
918 /* If we expected to find a vtable, but did not, let the user
919 know that we aren't happy, but don't throw an error.
920 FIXME: there has to be a better way to do this. */
921 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
922 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
923 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
924 VALUE_TYPE (in_arg
) = error_type
;
928 /* Now search through the virtual function table. */
929 entry
= value_ind (vtbl
);
930 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
931 for (i
= 1; i
<= nelems
; i
++)
933 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
935 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
936 /* If we use '<=' we can handle single inheritance
937 * where all offsets are zero - just use the first entry found. */
938 if (offset
<= best_offset
)
940 best_offset
= offset
;
944 /* Move the pointer according to BEST_ENTRY's offset, and figure
945 out what type we should return as the new pointer. */
948 /* An alternative method (which should no longer be necessary).
949 * But we leave it in for future use, when we will hopefully
950 * have optimizes the vtable to use thunks instead of offsets. */
951 /* Use the name of vtable itself to extract a base type. */
952 demangled_name
+= 4; /* Skip _vt$ prefix. */
956 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
957 sym
= find_pc_function (pc_for_sym
);
958 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), DMGL_ANSI
);
959 *(strchr (demangled_name
, ':')) = '\0';
961 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
963 error ("could not find type declaration for `%s'", demangled_name
);
966 free (demangled_name
);
967 arg
= value_add (value_cast (builtin_type_int
, arg
),
968 value_field (best_entry
, 0));
971 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
975 /* ARG is a pointer object of type TYPE. If TYPE has virtual
976 function tables, probe ARG's tables (including the vtables
977 of its baseclasses) to figure out the most derived type that ARG
978 could actually be a pointer to. */
981 value_from_vtable_info (arg
, type
)
985 /* Take care of preliminaries. */
986 if (TYPE_VPTR_FIELDNO (type
) < 0)
987 fill_in_vptr_fieldno (type
);
988 if (TYPE_VPTR_FIELDNO (type
) < 0 || VALUE_REPEATED (arg
))
991 return value_headof (arg
, 0, type
);
994 /* Return true if the INDEXth field of TYPE is a virtual baseclass
995 pointer which is for the base class whose type is BASECLASS. */
998 vb_match (type
, index
, basetype
)
1001 struct type
*basetype
;
1003 struct type
*fieldtype
;
1004 struct type
*fieldtype_target_type
;
1005 char *name
= TYPE_FIELD_NAME (type
, index
);
1006 char *field_class_name
= NULL
;
1010 /* gcc 2.4 uses _vb$. */
1011 if (name
[1] == 'v' && name
[2] == 'b' && name
[3] == CPLUS_MARKER
)
1012 field_class_name
= name
+ 4;
1013 /* gcc 2.5 will use __vb_. */
1014 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1015 field_class_name
= name
+ 5;
1017 if (field_class_name
== NULL
)
1018 /* This field is not a virtual base class pointer. */
1021 /* It's a virtual baseclass pointer, now we just need to find out whether
1022 it is for this baseclass. */
1023 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1024 if (fieldtype
== NULL
1025 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1026 /* "Can't happen". */
1029 /* What we check for is that either the types are equal (needed for
1030 nameless types) or have the same name. This is ugly, and a more
1031 elegant solution should be devised (which would probably just push
1032 the ugliness into symbol reading unless we change the stabs format). */
1033 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1036 if (TYPE_NAME (basetype
) != NULL
1037 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1038 && STREQ (TYPE_NAME (basetype
),
1039 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1044 /* Compute the offset of the baseclass which is
1045 the INDEXth baseclass of class TYPE, for a value ARG,
1046 wih extra offset of OFFSET.
1047 The result is the offste of the baseclass value relative
1048 to (the address of)(ARG) + OFFSET.
1050 -1 is returned on error. */
1053 baseclass_offset (type
, index
, arg
, offset
)
1059 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1061 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1063 /* Must hunt for the pointer to this virtual baseclass. */
1064 register int i
, len
= TYPE_NFIELDS (type
);
1065 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1067 /* First look for the virtual baseclass pointer
1069 for (i
= n_baseclasses
; i
< len
; i
++)
1071 if (vb_match (type
, i
, basetype
))
1074 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1075 VALUE_CONTENTS (arg
) + VALUE_OFFSET (arg
)
1077 + (TYPE_FIELD_BITPOS (type
, i
) / 8));
1079 if (VALUE_LVAL (arg
) != lval_memory
)
1083 (LONGEST
) (VALUE_ADDRESS (arg
) + VALUE_OFFSET (arg
) + offset
);
1086 /* Not in the fields, so try looking through the baseclasses. */
1087 for (i
= index
+1; i
< n_baseclasses
; i
++)
1090 baseclass_offset (type
, i
, arg
, offset
);
1098 /* Baseclass is easily computed. */
1099 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1102 /* Compute the address of the baseclass which is
1103 the INDEXth baseclass of class TYPE. The TYPE base
1104 of the object is at VALADDR.
1106 If ERRP is non-NULL, set *ERRP to be the errno code of any error,
1107 or 0 if no error. In that case the return value is not the address
1108 of the baseclasss, but the address which could not be read
1111 /* FIXME Fix remaining uses of baseclass_addr to use baseclass_offset */
1114 baseclass_addr (type
, index
, valaddr
, valuep
, errp
)
1121 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1126 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1128 /* Must hunt for the pointer to this virtual baseclass. */
1129 register int i
, len
= TYPE_NFIELDS (type
);
1130 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1132 /* First look for the virtual baseclass pointer
1134 for (i
= n_baseclasses
; i
< len
; i
++)
1136 if (vb_match (type
, i
, basetype
))
1138 value val
= allocate_value (basetype
);
1143 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1144 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1146 status
= target_read_memory (addr
,
1147 VALUE_CONTENTS_RAW (val
),
1148 TYPE_LENGTH (basetype
));
1149 VALUE_LVAL (val
) = lval_memory
;
1150 VALUE_ADDRESS (val
) = addr
;
1156 release_value (val
);
1160 return (char *)addr
;
1166 return (char *) VALUE_CONTENTS (val
);
1170 /* Not in the fields, so try looking through the baseclasses. */
1171 for (i
= index
+1; i
< n_baseclasses
; i
++)
1175 baddr
= baseclass_addr (type
, i
, valaddr
, valuep
, errp
);
1185 /* Baseclass is easily computed. */
1188 return valaddr
+ TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1191 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1194 Extracting bits depends on endianness of the machine. Compute the
1195 number of least significant bits to discard. For big endian machines,
1196 we compute the total number of bits in the anonymous object, subtract
1197 off the bit count from the MSB of the object to the MSB of the
1198 bitfield, then the size of the bitfield, which leaves the LSB discard
1199 count. For little endian machines, the discard count is simply the
1200 number of bits from the LSB of the anonymous object to the LSB of the
1203 If the field is signed, we also do sign extension. */
1206 unpack_field_as_long (type
, valaddr
, fieldno
)
1211 unsigned LONGEST val
;
1212 unsigned LONGEST valmask
;
1213 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1214 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1217 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1219 /* Extract bits. See comment above. */
1222 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1224 lsbcount
= (bitpos
% 8);
1228 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1229 If the field is signed, and is negative, then sign extend. */
1231 if ((bitsize
> 0) && (bitsize
< 8 * sizeof (val
)))
1233 valmask
= (((unsigned LONGEST
) 1) << bitsize
) - 1;
1235 if (!TYPE_UNSIGNED (TYPE_FIELD_TYPE (type
, fieldno
)))
1237 if (val
& (valmask
^ (valmask
>> 1)))
1246 /* Modify the value of a bitfield. ADDR points to a block of memory in
1247 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1248 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1249 indicate which bits (in target bit order) comprise the bitfield. */
1252 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1255 int bitpos
, bitsize
;
1259 /* Reject values too big to fit in the field in question,
1260 otherwise adjoining fields may be corrupted. */
1261 if (bitsize
< (8 * sizeof (fieldval
))
1262 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1264 /* FIXME: would like to include fieldval in the message, but
1265 we don't have a sprintf_longest. */
1266 error ("Value does not fit in %d bits.", bitsize
);
1269 oword
= extract_signed_integer (addr
, sizeof oword
);
1271 /* Shifting for bit field depends on endianness of the target machine. */
1273 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1276 /* Mask out old value, while avoiding shifts >= size of oword */
1277 if (bitsize
< 8 * sizeof (oword
))
1278 oword
&= ~(((((unsigned LONGEST
)1) << bitsize
) - 1) << bitpos
);
1280 oword
&= ~((~(unsigned LONGEST
)0) << bitpos
);
1281 oword
|= fieldval
<< bitpos
;
1283 store_signed_integer (addr
, sizeof oword
, oword
);
1286 /* Convert C numbers into newly allocated values */
1289 value_from_longest (type
, num
)
1291 register LONGEST num
;
1293 register value val
= allocate_value (type
);
1294 register enum type_code code
= TYPE_CODE (type
);
1295 register int len
= TYPE_LENGTH (type
);
1300 case TYPE_CODE_CHAR
:
1301 case TYPE_CODE_ENUM
:
1302 case TYPE_CODE_BOOL
:
1303 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1308 /* This assumes that all pointers of a given length
1309 have the same form. */
1310 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1314 error ("Unexpected type encountered for integer constant.");
1320 value_from_double (type
, num
)
1324 register value val
= allocate_value (type
);
1325 register enum type_code code
= TYPE_CODE (type
);
1326 register int len
= TYPE_LENGTH (type
);
1328 if (code
== TYPE_CODE_FLT
)
1330 if (len
== sizeof (float))
1331 * (float *) VALUE_CONTENTS_RAW (val
) = num
;
1332 else if (len
== sizeof (double))
1333 * (double *) VALUE_CONTENTS_RAW (val
) = num
;
1335 error ("Floating type encountered with unexpected data length.");
1338 error ("Unexpected type encountered for floating constant.");
1340 /* num was in host byte order. So now put the value's contents
1341 into target byte order. */
1342 SWAP_TARGET_AND_HOST (VALUE_CONTENTS_RAW (val
), len
);
1347 /* Deal with the value that is "about to be returned". */
1349 /* Return the value that a function returning now
1350 would be returning to its caller, assuming its type is VALTYPE.
1351 RETBUF is where we look for what ought to be the contents
1352 of the registers (in raw form). This is because it is often
1353 desirable to restore old values to those registers
1354 after saving the contents of interest, and then call
1355 this function using the saved values.
1356 struct_return is non-zero when the function in question is
1357 using the structure return conventions on the machine in question;
1358 0 when it is using the value returning conventions (this often
1359 means returning pointer to where structure is vs. returning value). */
1362 value_being_returned (valtype
, retbuf
, struct_return
)
1363 register struct type
*valtype
;
1364 char retbuf
[REGISTER_BYTES
];
1371 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1372 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1373 if (struct_return
) {
1374 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1376 error ("Function return value unknown");
1377 return value_at (valtype
, addr
);
1381 val
= allocate_value (valtype
);
1382 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1387 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1388 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1389 and TYPE is the type (which is known to be struct, union or array).
1391 On most machines, the struct convention is used unless we are
1392 using gcc and the type is of a special size. */
1393 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1394 native compiler. GCC 2.3.3 was the last release that did it the
1395 old way. Since gcc2_compiled was not changed, we have no
1396 way to correctly win in all cases, so we just do the right thing
1397 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1398 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1399 would cause more chaos than dealing with some struct returns being
1401 #if !defined (USE_STRUCT_CONVENTION)
1402 #define USE_STRUCT_CONVENTION(gcc_p, type)\
1403 (!((gcc_p == 1) && (TYPE_LENGTH (value_type) == 1 \
1404 || TYPE_LENGTH (value_type) == 2 \
1405 || TYPE_LENGTH (value_type) == 4 \
1406 || TYPE_LENGTH (value_type) == 8 \
1411 /* Return true if the function specified is using the structure returning
1412 convention on this machine to return arguments, or 0 if it is using
1413 the value returning convention. FUNCTION is the value representing
1414 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1415 is the type returned by the function. GCC_P is nonzero if compiled
1419 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1422 struct type
*value_type
;
1426 register enum type_code code
= TYPE_CODE (value_type
);
1428 if (code
== TYPE_CODE_ERROR
)
1429 error ("Function return type unknown.");
1431 if (code
== TYPE_CODE_STRUCT
||
1432 code
== TYPE_CODE_UNION
||
1433 code
== TYPE_CODE_ARRAY
)
1434 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1439 /* Store VAL so it will be returned if a function returns now.
1440 Does not verify that VAL's type matches what the current
1441 function wants to return. */
1444 set_return_value (val
)
1447 register enum type_code code
= TYPE_CODE (VALUE_TYPE (val
));
1451 if (code
== TYPE_CODE_ERROR
)
1452 error ("Function return type unknown.");
1454 if ( code
== TYPE_CODE_STRUCT
1455 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1456 error ("GDB does not support specifying a struct or union return value.");
1458 /* FIXME, this is bogus. We don't know what the return conventions
1459 are, or how values should be promoted.... */
1460 if (code
== TYPE_CODE_FLT
)
1462 dbuf
= value_as_double (val
);
1464 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&dbuf
);
1468 lbuf
= value_as_long (val
);
1469 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&lbuf
);
1474 _initialize_values ()
1476 add_cmd ("convenience", no_class
, show_convenience
,
1477 "Debugger convenience (\"$foo\") variables.\n\
1478 These variables are created when you assign them values;\n\
1479 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1480 A few convenience variables are given values automatically:\n\
1481 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1482 \"$__\" holds the contents of the last address examined with \"x\".",
1485 add_cmd ("values", no_class
, show_values
,
1486 "Elements of value history around item number IDX (or last ten).",