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. */
556 /* ADDR_BITS_REMOVE is wrong if we are being called for a
557 non-address (e.g. argument to "signal", "info break", etc.), or
558 for pointers to char, in which the low bits *are* significant. */
559 return ADDR_BITS_REMOVE(value_as_long (val
));
561 return value_as_long (val
);
565 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
566 as a long, or as a double, assuming the raw data is described
567 by type TYPE. Knows how to convert different sizes of values
568 and can convert between fixed and floating point. We don't assume
569 any alignment for the raw data. Return value is in host byte order.
571 If you want functions and arrays to be coerced to pointers, and
572 references to be dereferenced, call value_as_long() instead.
574 C++: It is assumed that the front-end has taken care of
575 all matters concerning pointers to members. A pointer
576 to member which reaches here is considered to be equivalent
577 to an INT (or some size). After all, it is only an offset. */
579 /* FIXME: This should be rewritten as a switch statement for speed and
580 ease of comprehension. */
583 unpack_long (type
, valaddr
)
587 register enum type_code code
= TYPE_CODE (type
);
588 register int len
= TYPE_LENGTH (type
);
589 register int nosign
= TYPE_UNSIGNED (type
);
591 if (code
== TYPE_CODE_ENUM
|| code
== TYPE_CODE_BOOL
)
592 code
= TYPE_CODE_INT
;
593 if (code
== TYPE_CODE_FLT
)
595 if (len
== sizeof (float))
598 memcpy (&retval
, valaddr
, sizeof (retval
));
599 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
603 if (len
== sizeof (double))
606 memcpy (&retval
, valaddr
, sizeof (retval
));
607 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
612 error ("Unexpected type of floating point number.");
615 else if ((code
== TYPE_CODE_INT
|| code
== TYPE_CODE_CHAR
) && nosign
)
617 return extract_unsigned_integer (valaddr
, len
);
619 else if (code
== TYPE_CODE_INT
|| code
== TYPE_CODE_CHAR
)
621 return extract_signed_integer (valaddr
, len
);
623 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
624 whether we want this to be true eventually. */
625 else if (code
== TYPE_CODE_PTR
|| code
== TYPE_CODE_REF
)
627 return extract_address (valaddr
, len
);
629 else if (code
== TYPE_CODE_MEMBER
)
630 error ("not implemented: member types in unpack_long");
632 error ("Value not integer or pointer.");
633 return 0; /* For lint -- never reached */
636 /* Return a double value from the specified type and address.
637 INVP points to an int which is set to 0 for valid value,
638 1 for invalid value (bad float format). In either case,
639 the returned double is OK to use. Argument is in target
640 format, result is in host format. */
643 unpack_double (type
, valaddr
, invp
)
648 register enum type_code code
= TYPE_CODE (type
);
649 register int len
= TYPE_LENGTH (type
);
650 register int nosign
= TYPE_UNSIGNED (type
);
652 *invp
= 0; /* Assume valid. */
653 if (code
== TYPE_CODE_FLT
)
655 if (INVALID_FLOAT (valaddr
, len
))
658 return 1.234567891011121314;
661 if (len
== sizeof (float))
664 memcpy (&retval
, valaddr
, sizeof (retval
));
665 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
669 if (len
== sizeof (double))
672 memcpy (&retval
, valaddr
, sizeof (retval
));
673 SWAP_TARGET_AND_HOST (&retval
, sizeof (retval
));
678 error ("Unexpected type of floating point number.");
679 return 0; /* Placate lint. */
683 /* Unsigned -- be sure we compensate for signed LONGEST. */
684 return (unsigned LONGEST
) unpack_long (type
, valaddr
);
686 /* Signed -- we are OK with unpack_long. */
687 return unpack_long (type
, valaddr
);
691 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
692 as a CORE_ADDR, assuming the raw data is described by type TYPE.
693 We don't assume any alignment for the raw data. Return value is in
696 If you want functions and arrays to be coerced to pointers, and
697 references to be dereferenced, call value_as_pointer() instead.
699 C++: It is assumed that the front-end has taken care of
700 all matters concerning pointers to members. A pointer
701 to member which reaches here is considered to be equivalent
702 to an INT (or some size). After all, it is only an offset. */
705 unpack_pointer (type
, valaddr
)
709 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
710 whether we want this to be true eventually. */
711 return unpack_long (type
, valaddr
);
714 /* Given a value ARG1 (offset by OFFSET bytes)
715 of a struct or union type ARG_TYPE,
716 extract and return the value of one of its fields.
717 FIELDNO says which field.
719 For C++, must also be able to return values from static fields */
722 value_primitive_field (arg1
, offset
, fieldno
, arg_type
)
725 register int fieldno
;
726 register struct type
*arg_type
;
729 register struct type
*type
;
731 check_stub_type (arg_type
);
732 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
734 /* Handle packed fields */
736 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
737 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
739 v
= value_from_longest (type
,
740 unpack_field_as_long (arg_type
,
741 VALUE_CONTENTS (arg1
),
743 VALUE_BITPOS (v
) = TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
744 VALUE_BITSIZE (v
) = TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
748 v
= allocate_value (type
);
749 if (VALUE_LAZY (arg1
))
752 memcpy (VALUE_CONTENTS_RAW (v
), VALUE_CONTENTS_RAW (arg1
) + offset
,
755 VALUE_LVAL (v
) = VALUE_LVAL (arg1
);
756 if (VALUE_LVAL (arg1
) == lval_internalvar
)
757 VALUE_LVAL (v
) = lval_internalvar_component
;
758 VALUE_ADDRESS (v
) = VALUE_ADDRESS (arg1
);
759 VALUE_OFFSET (v
) = offset
+ VALUE_OFFSET (arg1
);
763 /* Given a value ARG1 of a struct or union type,
764 extract and return the value of one of its fields.
765 FIELDNO says which field.
767 For C++, must also be able to return values from static fields */
770 value_field (arg1
, fieldno
)
772 register int fieldno
;
774 return value_primitive_field (arg1
, 0, fieldno
, VALUE_TYPE (arg1
));
777 /* Return a non-virtual function as a value.
778 F is the list of member functions which contains the desired method.
779 J is an index into F which provides the desired method. */
782 value_fn_field (arg1p
, f
, j
, type
, offset
)
790 register struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
793 sym
= lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f
, j
),
794 0, VAR_NAMESPACE
, 0, NULL
);
795 if (! sym
) error ("Internal error: could not find physical method named %s",
796 TYPE_FN_FIELD_PHYSNAME (f
, j
));
798 v
= allocate_value (ftype
);
799 VALUE_ADDRESS (v
) = BLOCK_START (SYMBOL_BLOCK_VALUE (sym
));
800 VALUE_TYPE (v
) = ftype
;
804 if (type
!= VALUE_TYPE (*arg1p
))
805 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
806 value_addr (*arg1p
)));
808 /* Move the `this' pointer according to the offset. */
809 VALUE_OFFSET (*arg1p
) += offset
;
815 /* Return a virtual function as a value.
816 ARG1 is the object which provides the virtual function
817 table pointer. *ARG1P is side-effected in calling this function.
818 F is the list of member functions which contains the desired virtual
820 J is an index into F which provides the desired virtual function.
822 TYPE is the type in which F is located. */
824 value_virtual_fn_field (arg1p
, f
, j
, type
, offset
)
832 /* First, get the virtual function table pointer. That comes
833 with a strange type, so cast it to type `pointer to long' (which
834 should serve just fine as a function type). Then, index into
835 the table, and convert final value to appropriate function type. */
836 value entry
, vfn
, vtbl
;
837 value vi
= value_from_longest (builtin_type_int
,
838 (LONGEST
) TYPE_FN_FIELD_VOFFSET (f
, j
));
839 struct type
*fcontext
= TYPE_FN_FIELD_FCONTEXT (f
, j
);
840 struct type
*context
;
841 if (fcontext
== NULL
)
842 /* We don't have an fcontext (e.g. the program was compiled with
843 g++ version 1). Try to get the vtbl from the TYPE_VPTR_BASETYPE.
844 This won't work right for multiple inheritance, but at least we
845 should do as well as GDB 3.x did. */
846 fcontext
= TYPE_VPTR_BASETYPE (type
);
847 context
= lookup_pointer_type (fcontext
);
848 /* Now context is a pointer to the basetype containing the vtbl. */
849 if (TYPE_TARGET_TYPE (context
) != VALUE_TYPE (arg1
))
850 arg1
= value_ind (value_cast (context
, value_addr (arg1
)));
852 context
= VALUE_TYPE (arg1
);
853 /* Now context is the basetype containing the vtbl. */
855 /* This type may have been defined before its virtual function table
856 was. If so, fill in the virtual function table entry for the
858 if (TYPE_VPTR_FIELDNO (context
) < 0)
859 fill_in_vptr_fieldno (context
);
861 /* The virtual function table is now an array of structures
862 which have the form { int16 offset, delta; void *pfn; }. */
863 vtbl
= value_ind (value_primitive_field (arg1
, 0,
864 TYPE_VPTR_FIELDNO (context
),
865 TYPE_VPTR_BASETYPE (context
)));
867 /* Index into the virtual function table. This is hard-coded because
868 looking up a field is not cheap, and it may be important to save
869 time, e.g. if the user has set a conditional breakpoint calling
870 a virtual function. */
871 entry
= value_subscript (vtbl
, vi
);
873 /* Move the `this' pointer according to the virtual function table. */
874 VALUE_OFFSET (arg1
) += value_as_long (value_field (entry
, 0)) + offset
;
875 if (! VALUE_LAZY (arg1
))
877 VALUE_LAZY (arg1
) = 1;
878 value_fetch_lazy (arg1
);
881 vfn
= value_field (entry
, 2);
882 /* Reinstantiate the function pointer with the correct type. */
883 VALUE_TYPE (vfn
) = lookup_pointer_type (TYPE_FN_FIELD_TYPE (f
, j
));
889 /* ARG is a pointer to an object we know to be at least
890 a DTYPE. BTYPE is the most derived basetype that has
891 already been searched (and need not be searched again).
892 After looking at the vtables between BTYPE and DTYPE,
893 return the most derived type we find. The caller must
894 be satisfied when the return value == DTYPE.
896 FIXME-tiemann: should work with dossier entries as well. */
899 value_headof (in_arg
, btype
, dtype
)
901 struct type
*btype
, *dtype
;
903 /* First collect the vtables we must look at for this object. */
904 /* FIXME-tiemann: right now, just look at top-most vtable. */
905 value arg
, vtbl
, entry
, best_entry
= 0;
907 int offset
, best_offset
= 0;
909 CORE_ADDR pc_for_sym
;
910 char *demangled_name
;
911 struct minimal_symbol
*msymbol
;
913 btype
= TYPE_VPTR_BASETYPE (dtype
);
914 check_stub_type (btype
);
917 arg
= value_cast (lookup_pointer_type (btype
), arg
);
918 vtbl
= value_ind (value_field (value_ind (arg
), TYPE_VPTR_FIELDNO (btype
)));
920 /* Check that VTBL looks like it points to a virtual function table. */
921 msymbol
= lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtbl
));
923 || !VTBL_PREFIX_P (demangled_name
= SYMBOL_NAME (msymbol
)))
925 /* If we expected to find a vtable, but did not, let the user
926 know that we aren't happy, but don't throw an error.
927 FIXME: there has to be a better way to do this. */
928 struct type
*error_type
= (struct type
*)xmalloc (sizeof (struct type
));
929 memcpy (error_type
, VALUE_TYPE (in_arg
), sizeof (struct type
));
930 TYPE_NAME (error_type
) = savestring ("suspicious *", sizeof ("suspicious *"));
931 VALUE_TYPE (in_arg
) = error_type
;
935 /* Now search through the virtual function table. */
936 entry
= value_ind (vtbl
);
937 nelems
= longest_to_int (value_as_long (value_field (entry
, 2)));
938 for (i
= 1; i
<= nelems
; i
++)
940 entry
= value_subscript (vtbl
, value_from_longest (builtin_type_int
,
942 offset
= longest_to_int (value_as_long (value_field (entry
, 0)));
943 /* If we use '<=' we can handle single inheritance
944 * where all offsets are zero - just use the first entry found. */
945 if (offset
<= best_offset
)
947 best_offset
= offset
;
951 /* Move the pointer according to BEST_ENTRY's offset, and figure
952 out what type we should return as the new pointer. */
955 /* An alternative method (which should no longer be necessary).
956 * But we leave it in for future use, when we will hopefully
957 * have optimizes the vtable to use thunks instead of offsets. */
958 /* Use the name of vtable itself to extract a base type. */
959 demangled_name
+= 4; /* Skip _vt$ prefix. */
963 pc_for_sym
= value_as_pointer (value_field (best_entry
, 2));
964 sym
= find_pc_function (pc_for_sym
);
965 demangled_name
= cplus_demangle (SYMBOL_NAME (sym
), DMGL_ANSI
);
966 *(strchr (demangled_name
, ':')) = '\0';
968 sym
= lookup_symbol (demangled_name
, 0, VAR_NAMESPACE
, 0, 0);
970 error ("could not find type declaration for `%s'", demangled_name
);
973 free (demangled_name
);
974 arg
= value_add (value_cast (builtin_type_int
, arg
),
975 value_field (best_entry
, 0));
978 VALUE_TYPE (arg
) = lookup_pointer_type (SYMBOL_TYPE (sym
));
982 /* ARG is a pointer object of type TYPE. If TYPE has virtual
983 function tables, probe ARG's tables (including the vtables
984 of its baseclasses) to figure out the most derived type that ARG
985 could actually be a pointer to. */
988 value_from_vtable_info (arg
, type
)
992 /* Take care of preliminaries. */
993 if (TYPE_VPTR_FIELDNO (type
) < 0)
994 fill_in_vptr_fieldno (type
);
995 if (TYPE_VPTR_FIELDNO (type
) < 0 || VALUE_REPEATED (arg
))
998 return value_headof (arg
, 0, type
);
1001 /* Return true if the INDEXth field of TYPE is a virtual baseclass
1002 pointer which is for the base class whose type is BASECLASS. */
1005 vb_match (type
, index
, basetype
)
1008 struct type
*basetype
;
1010 struct type
*fieldtype
;
1011 struct type
*fieldtype_target_type
;
1012 char *name
= TYPE_FIELD_NAME (type
, index
);
1013 char *field_class_name
= NULL
;
1017 /* gcc 2.4 uses _vb$. */
1018 if (name
[1] == 'v' && name
[2] == 'b' && name
[3] == CPLUS_MARKER
)
1019 field_class_name
= name
+ 4;
1020 /* gcc 2.5 will use __vb_. */
1021 if (name
[1] == '_' && name
[2] == 'v' && name
[3] == 'b' && name
[4] == '_')
1022 field_class_name
= name
+ 5;
1024 if (field_class_name
== NULL
)
1025 /* This field is not a virtual base class pointer. */
1028 /* It's a virtual baseclass pointer, now we just need to find out whether
1029 it is for this baseclass. */
1030 fieldtype
= TYPE_FIELD_TYPE (type
, index
);
1031 if (fieldtype
== NULL
1032 || TYPE_CODE (fieldtype
) != TYPE_CODE_PTR
)
1033 /* "Can't happen". */
1036 /* What we check for is that either the types are equal (needed for
1037 nameless types) or have the same name. This is ugly, and a more
1038 elegant solution should be devised (which would probably just push
1039 the ugliness into symbol reading unless we change the stabs format). */
1040 if (TYPE_TARGET_TYPE (fieldtype
) == basetype
)
1043 if (TYPE_NAME (basetype
) != NULL
1044 && TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
)) != NULL
1045 && STREQ (TYPE_NAME (basetype
),
1046 TYPE_NAME (TYPE_TARGET_TYPE (fieldtype
))))
1051 /* Compute the offset of the baseclass which is
1052 the INDEXth baseclass of class TYPE, for a value ARG,
1053 wih extra offset of OFFSET.
1054 The result is the offste of the baseclass value relative
1055 to (the address of)(ARG) + OFFSET.
1057 -1 is returned on error. */
1060 baseclass_offset (type
, index
, arg
, offset
)
1066 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1068 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1070 /* Must hunt for the pointer to this virtual baseclass. */
1071 register int i
, len
= TYPE_NFIELDS (type
);
1072 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1074 /* First look for the virtual baseclass pointer
1076 for (i
= n_baseclasses
; i
< len
; i
++)
1078 if (vb_match (type
, i
, basetype
))
1081 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1082 VALUE_CONTENTS (arg
) + VALUE_OFFSET (arg
)
1084 + (TYPE_FIELD_BITPOS (type
, i
) / 8));
1086 if (VALUE_LVAL (arg
) != lval_memory
)
1090 (LONGEST
) (VALUE_ADDRESS (arg
) + VALUE_OFFSET (arg
) + offset
);
1093 /* Not in the fields, so try looking through the baseclasses. */
1094 for (i
= index
+1; i
< n_baseclasses
; i
++)
1097 baseclass_offset (type
, i
, arg
, offset
);
1105 /* Baseclass is easily computed. */
1106 return TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1109 /* Compute the address of the baseclass which is
1110 the INDEXth baseclass of class TYPE. The TYPE base
1111 of the object is at VALADDR.
1113 If ERRP is non-NULL, set *ERRP to be the errno code of any error,
1114 or 0 if no error. In that case the return value is not the address
1115 of the baseclasss, but the address which could not be read
1118 /* FIXME Fix remaining uses of baseclass_addr to use baseclass_offset */
1121 baseclass_addr (type
, index
, valaddr
, valuep
, errp
)
1128 struct type
*basetype
= TYPE_BASECLASS (type
, index
);
1133 if (BASETYPE_VIA_VIRTUAL (type
, index
))
1135 /* Must hunt for the pointer to this virtual baseclass. */
1136 register int i
, len
= TYPE_NFIELDS (type
);
1137 register int n_baseclasses
= TYPE_N_BASECLASSES (type
);
1139 /* First look for the virtual baseclass pointer
1141 for (i
= n_baseclasses
; i
< len
; i
++)
1143 if (vb_match (type
, i
, basetype
))
1145 value val
= allocate_value (basetype
);
1150 = unpack_pointer (TYPE_FIELD_TYPE (type
, i
),
1151 valaddr
+ (TYPE_FIELD_BITPOS (type
, i
) / 8));
1153 status
= target_read_memory (addr
,
1154 VALUE_CONTENTS_RAW (val
),
1155 TYPE_LENGTH (basetype
));
1156 VALUE_LVAL (val
) = lval_memory
;
1157 VALUE_ADDRESS (val
) = addr
;
1163 release_value (val
);
1167 return (char *)addr
;
1173 return (char *) VALUE_CONTENTS (val
);
1177 /* Not in the fields, so try looking through the baseclasses. */
1178 for (i
= index
+1; i
< n_baseclasses
; i
++)
1182 baddr
= baseclass_addr (type
, i
, valaddr
, valuep
, errp
);
1192 /* Baseclass is easily computed. */
1195 return valaddr
+ TYPE_BASECLASS_BITPOS (type
, index
) / 8;
1198 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1201 Extracting bits depends on endianness of the machine. Compute the
1202 number of least significant bits to discard. For big endian machines,
1203 we compute the total number of bits in the anonymous object, subtract
1204 off the bit count from the MSB of the object to the MSB of the
1205 bitfield, then the size of the bitfield, which leaves the LSB discard
1206 count. For little endian machines, the discard count is simply the
1207 number of bits from the LSB of the anonymous object to the LSB of the
1210 If the field is signed, we also do sign extension. */
1213 unpack_field_as_long (type
, valaddr
, fieldno
)
1218 unsigned LONGEST val
;
1219 unsigned LONGEST valmask
;
1220 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1221 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1224 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1226 /* Extract bits. See comment above. */
1229 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1231 lsbcount
= (bitpos
% 8);
1235 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1236 If the field is signed, and is negative, then sign extend. */
1238 if ((bitsize
> 0) && (bitsize
< 8 * sizeof (val
)))
1240 valmask
= (((unsigned LONGEST
) 1) << bitsize
) - 1;
1242 if (!TYPE_UNSIGNED (TYPE_FIELD_TYPE (type
, fieldno
)))
1244 if (val
& (valmask
^ (valmask
>> 1)))
1253 /* Modify the value of a bitfield. ADDR points to a block of memory in
1254 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
1255 is the desired value of the field, in host byte order. BITPOS and BITSIZE
1256 indicate which bits (in target bit order) comprise the bitfield. */
1259 modify_field (addr
, fieldval
, bitpos
, bitsize
)
1262 int bitpos
, bitsize
;
1266 /* Reject values too big to fit in the field in question,
1267 otherwise adjoining fields may be corrupted. */
1268 if (bitsize
< (8 * sizeof (fieldval
))
1269 && 0 != (fieldval
& ~((1<<bitsize
)-1)))
1271 /* FIXME: would like to include fieldval in the message, but
1272 we don't have a sprintf_longest. */
1273 error ("Value does not fit in %d bits.", bitsize
);
1276 oword
= extract_signed_integer (addr
, sizeof oword
);
1278 /* Shifting for bit field depends on endianness of the target machine. */
1280 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
1283 /* Mask out old value, while avoiding shifts >= size of oword */
1284 if (bitsize
< 8 * sizeof (oword
))
1285 oword
&= ~(((((unsigned LONGEST
)1) << bitsize
) - 1) << bitpos
);
1287 oword
&= ~((~(unsigned LONGEST
)0) << bitpos
);
1288 oword
|= fieldval
<< bitpos
;
1290 store_signed_integer (addr
, sizeof oword
, oword
);
1293 /* Convert C numbers into newly allocated values */
1296 value_from_longest (type
, num
)
1298 register LONGEST num
;
1300 register value val
= allocate_value (type
);
1301 register enum type_code code
= TYPE_CODE (type
);
1302 register int len
= TYPE_LENGTH (type
);
1307 case TYPE_CODE_CHAR
:
1308 case TYPE_CODE_ENUM
:
1309 case TYPE_CODE_BOOL
:
1310 store_signed_integer (VALUE_CONTENTS_RAW (val
), len
, num
);
1315 /* This assumes that all pointers of a given length
1316 have the same form. */
1317 store_address (VALUE_CONTENTS_RAW (val
), len
, (CORE_ADDR
) num
);
1321 error ("Unexpected type encountered for integer constant.");
1327 value_from_double (type
, num
)
1331 register value val
= allocate_value (type
);
1332 register enum type_code code
= TYPE_CODE (type
);
1333 register int len
= TYPE_LENGTH (type
);
1335 if (code
== TYPE_CODE_FLT
)
1337 if (len
== sizeof (float))
1338 * (float *) VALUE_CONTENTS_RAW (val
) = num
;
1339 else if (len
== sizeof (double))
1340 * (double *) VALUE_CONTENTS_RAW (val
) = num
;
1342 error ("Floating type encountered with unexpected data length.");
1345 error ("Unexpected type encountered for floating constant.");
1347 /* num was in host byte order. So now put the value's contents
1348 into target byte order. */
1349 SWAP_TARGET_AND_HOST (VALUE_CONTENTS_RAW (val
), len
);
1354 /* Deal with the value that is "about to be returned". */
1356 /* Return the value that a function returning now
1357 would be returning to its caller, assuming its type is VALTYPE.
1358 RETBUF is where we look for what ought to be the contents
1359 of the registers (in raw form). This is because it is often
1360 desirable to restore old values to those registers
1361 after saving the contents of interest, and then call
1362 this function using the saved values.
1363 struct_return is non-zero when the function in question is
1364 using the structure return conventions on the machine in question;
1365 0 when it is using the value returning conventions (this often
1366 means returning pointer to where structure is vs. returning value). */
1369 value_being_returned (valtype
, retbuf
, struct_return
)
1370 register struct type
*valtype
;
1371 char retbuf
[REGISTER_BYTES
];
1378 #if defined (EXTRACT_STRUCT_VALUE_ADDRESS)
1379 /* If this is not defined, just use EXTRACT_RETURN_VALUE instead. */
1380 if (struct_return
) {
1381 addr
= EXTRACT_STRUCT_VALUE_ADDRESS (retbuf
);
1383 error ("Function return value unknown");
1384 return value_at (valtype
, addr
);
1388 val
= allocate_value (valtype
);
1389 EXTRACT_RETURN_VALUE (valtype
, retbuf
, VALUE_CONTENTS_RAW (val
));
1394 /* Should we use EXTRACT_STRUCT_VALUE_ADDRESS instead of
1395 EXTRACT_RETURN_VALUE? GCC_P is true if compiled with gcc
1396 and TYPE is the type (which is known to be struct, union or array).
1398 On most machines, the struct convention is used unless we are
1399 using gcc and the type is of a special size. */
1400 /* As of about 31 Mar 93, GCC was changed to be compatible with the
1401 native compiler. GCC 2.3.3 was the last release that did it the
1402 old way. Since gcc2_compiled was not changed, we have no
1403 way to correctly win in all cases, so we just do the right thing
1404 for gcc1 and for gcc2 after this change. Thus it loses for gcc
1405 2.0-2.3.3. This is somewhat unfortunate, but changing gcc2_compiled
1406 would cause more chaos than dealing with some struct returns being
1408 #if !defined (USE_STRUCT_CONVENTION)
1409 #define USE_STRUCT_CONVENTION(gcc_p, type)\
1410 (!((gcc_p == 1) && (TYPE_LENGTH (value_type) == 1 \
1411 || TYPE_LENGTH (value_type) == 2 \
1412 || TYPE_LENGTH (value_type) == 4 \
1413 || TYPE_LENGTH (value_type) == 8 \
1418 /* Return true if the function specified is using the structure returning
1419 convention on this machine to return arguments, or 0 if it is using
1420 the value returning convention. FUNCTION is the value representing
1421 the function, FUNCADDR is the address of the function, and VALUE_TYPE
1422 is the type returned by the function. GCC_P is nonzero if compiled
1426 using_struct_return (function
, funcaddr
, value_type
, gcc_p
)
1429 struct type
*value_type
;
1433 register enum type_code code
= TYPE_CODE (value_type
);
1435 if (code
== TYPE_CODE_ERROR
)
1436 error ("Function return type unknown.");
1438 if (code
== TYPE_CODE_STRUCT
||
1439 code
== TYPE_CODE_UNION
||
1440 code
== TYPE_CODE_ARRAY
)
1441 return USE_STRUCT_CONVENTION (gcc_p
, value_type
);
1446 /* Store VAL so it will be returned if a function returns now.
1447 Does not verify that VAL's type matches what the current
1448 function wants to return. */
1451 set_return_value (val
)
1454 register enum type_code code
= TYPE_CODE (VALUE_TYPE (val
));
1458 if (code
== TYPE_CODE_ERROR
)
1459 error ("Function return type unknown.");
1461 if ( code
== TYPE_CODE_STRUCT
1462 || code
== TYPE_CODE_UNION
) /* FIXME, implement struct return. */
1463 error ("GDB does not support specifying a struct or union return value.");
1465 /* FIXME, this is bogus. We don't know what the return conventions
1466 are, or how values should be promoted.... */
1467 if (code
== TYPE_CODE_FLT
)
1469 dbuf
= value_as_double (val
);
1471 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&dbuf
);
1475 lbuf
= value_as_long (val
);
1476 STORE_RETURN_VALUE (VALUE_TYPE (val
), (char *)&lbuf
);
1481 _initialize_values ()
1483 add_cmd ("convenience", no_class
, show_convenience
,
1484 "Debugger convenience (\"$foo\") variables.\n\
1485 These variables are created when you assign them values;\n\
1486 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\n\
1487 A few convenience variables are given values automatically:\n\
1488 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
1489 \"$__\" holds the contents of the last address examined with \"x\".",
1492 add_cmd ("values", no_class
, show_values
,
1493 "Elements of value history around item number IDX (or last ten).",