1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006, 2007, 2008,
5 2009 Free Software Foundation, Inc.
7 This file is part of GDB.
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
23 #include "gdb_string.h"
34 #include "gdb_assert.h"
40 #include "cli/cli-decode.h"
42 #include "python/python.h"
44 /* Prototypes for exported functions. */
46 void _initialize_values (void);
48 /* Definition of a user function. */
49 struct internal_function
51 /* The name of the function. It is a bit odd to have this in the
52 function itself -- the user might use a differently-named
53 convenience variable to hold the function. */
57 internal_function_fn handler
;
59 /* User data for the handler. */
63 static struct cmd_list_element
*functionlist
;
67 /* Type of value; either not an lval, or one of the various
68 different possible kinds of lval. */
71 /* Is it modifiable? Only relevant if lval != not_lval. */
74 /* Location of value (if lval). */
77 /* If lval == lval_memory, this is the address in the inferior.
78 If lval == lval_register, this is the byte offset into the
79 registers structure. */
82 /* Pointer to internal variable. */
83 struct internalvar
*internalvar
;
85 /* If lval == lval_computed, this is a set of function pointers
86 to use to access and describe the value, and a closure pointer
90 struct lval_funcs
*funcs
; /* Functions to call. */
91 void *closure
; /* Closure for those functions to use. */
95 /* Describes offset of a value within lval of a structure in bytes.
96 If lval == lval_memory, this is an offset to the address. If
97 lval == lval_register, this is a further offset from
98 location.address within the registers structure. Note also the
99 member embedded_offset below. */
102 /* Only used for bitfields; number of bits contained in them. */
105 /* Only used for bitfields; position of start of field. For
106 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
107 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
110 /* Frame register value is relative to. This will be described in
111 the lval enum above as "lval_register". */
112 struct frame_id frame_id
;
114 /* Type of the value. */
117 /* If a value represents a C++ object, then the `type' field gives
118 the object's compile-time type. If the object actually belongs
119 to some class derived from `type', perhaps with other base
120 classes and additional members, then `type' is just a subobject
121 of the real thing, and the full object is probably larger than
122 `type' would suggest.
124 If `type' is a dynamic class (i.e. one with a vtable), then GDB
125 can actually determine the object's run-time type by looking at
126 the run-time type information in the vtable. When this
127 information is available, we may elect to read in the entire
128 object, for several reasons:
130 - When printing the value, the user would probably rather see the
131 full object, not just the limited portion apparent from the
134 - If `type' has virtual base classes, then even printing `type'
135 alone may require reaching outside the `type' portion of the
136 object to wherever the virtual base class has been stored.
138 When we store the entire object, `enclosing_type' is the run-time
139 type -- the complete object -- and `embedded_offset' is the
140 offset of `type' within that larger type, in bytes. The
141 value_contents() macro takes `embedded_offset' into account, so
142 most GDB code continues to see the `type' portion of the value,
143 just as the inferior would.
145 If `type' is a pointer to an object, then `enclosing_type' is a
146 pointer to the object's run-time type, and `pointed_to_offset' is
147 the offset in bytes from the full object to the pointed-to object
148 -- that is, the value `embedded_offset' would have if we followed
149 the pointer and fetched the complete object. (I don't really see
150 the point. Why not just determine the run-time type when you
151 indirect, and avoid the special case? The contents don't matter
152 until you indirect anyway.)
154 If we're not doing anything fancy, `enclosing_type' is equal to
155 `type', and `embedded_offset' is zero, so everything works
157 struct type
*enclosing_type
;
159 int pointed_to_offset
;
161 /* Values are stored in a chain, so that they can be deleted easily
162 over calls to the inferior. Values assigned to internal
163 variables, put into the value history or exposed to Python are
164 taken off this list. */
167 /* Register number if the value is from a register. */
170 /* If zero, contents of this value are in the contents field. If
171 nonzero, contents are in inferior. If the lval field is lval_memory,
172 the contents are in inferior memory at location.address plus offset.
173 The lval field may also be lval_register.
175 WARNING: This field is used by the code which handles watchpoints
176 (see breakpoint.c) to decide whether a particular value can be
177 watched by hardware watchpoints. If the lazy flag is set for
178 some member of a value chain, it is assumed that this member of
179 the chain doesn't need to be watched as part of watching the
180 value itself. This is how GDB avoids watching the entire struct
181 or array when the user wants to watch a single struct member or
182 array element. If you ever change the way lazy flag is set and
183 reset, be sure to consider this use as well! */
186 /* If nonzero, this is the value of a variable which does not
187 actually exist in the program. */
190 /* If value is a variable, is it initialized or not. */
193 /* Actual contents of the value. Target byte-order. NULL or not
194 valid if lazy is nonzero. */
198 /* Prototypes for local functions. */
200 static void show_values (char *, int);
202 static void show_convenience (char *, int);
205 /* The value-history records all the values printed
206 by print commands during this session. Each chunk
207 records 60 consecutive values. The first chunk on
208 the chain records the most recent values.
209 The total number of values is in value_history_count. */
211 #define VALUE_HISTORY_CHUNK 60
213 struct value_history_chunk
215 struct value_history_chunk
*next
;
216 struct value
*values
[VALUE_HISTORY_CHUNK
];
219 /* Chain of chunks now in use. */
221 static struct value_history_chunk
*value_history_chain
;
223 static int value_history_count
; /* Abs number of last entry stored */
226 /* List of all value objects currently allocated
227 (except for those released by calls to release_value)
228 This is so they can be freed after each command. */
230 static struct value
*all_values
;
232 /* Allocate a lazy value for type TYPE. Its actual content is
233 "lazily" allocated too: the content field of the return value is
234 NULL; it will be allocated when it is fetched from the target. */
237 allocate_value_lazy (struct type
*type
)
240 struct type
*atype
= check_typedef (type
);
242 val
= (struct value
*) xzalloc (sizeof (struct value
));
243 val
->contents
= NULL
;
244 val
->next
= all_values
;
247 val
->enclosing_type
= type
;
248 VALUE_LVAL (val
) = not_lval
;
249 val
->location
.address
= 0;
250 VALUE_FRAME_ID (val
) = null_frame_id
;
254 VALUE_REGNUM (val
) = -1;
256 val
->optimized_out
= 0;
257 val
->embedded_offset
= 0;
258 val
->pointed_to_offset
= 0;
260 val
->initialized
= 1; /* Default to initialized. */
264 /* Allocate the contents of VAL if it has not been allocated yet. */
267 allocate_value_contents (struct value
*val
)
270 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
273 /* Allocate a value and its contents for type TYPE. */
276 allocate_value (struct type
*type
)
278 struct value
*val
= allocate_value_lazy (type
);
279 allocate_value_contents (val
);
284 /* Allocate a value that has the correct length
285 for COUNT repetitions of type TYPE. */
288 allocate_repeat_value (struct type
*type
, int count
)
290 int low_bound
= current_language
->string_lower_bound
; /* ??? */
291 /* FIXME-type-allocation: need a way to free this type when we are
293 struct type
*array_type
294 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
295 return allocate_value (array_type
);
298 /* Needed if another module needs to maintain its on list of values. */
300 value_prepend_to_list (struct value
**head
, struct value
*val
)
306 /* Needed if another module needs to maintain its on list of values. */
308 value_remove_from_list (struct value
**head
, struct value
*val
)
313 *head
= (*head
)->next
;
315 for (prev
= *head
; prev
->next
; prev
= prev
->next
)
316 if (prev
->next
== val
)
318 prev
->next
= val
->next
;
324 allocate_computed_value (struct type
*type
,
325 struct lval_funcs
*funcs
,
328 struct value
*v
= allocate_value (type
);
329 VALUE_LVAL (v
) = lval_computed
;
330 v
->location
.computed
.funcs
= funcs
;
331 v
->location
.computed
.closure
= closure
;
332 set_value_lazy (v
, 1);
337 /* Accessor methods. */
340 value_next (struct value
*value
)
346 value_type (struct value
*value
)
351 deprecated_set_value_type (struct value
*value
, struct type
*type
)
357 value_offset (struct value
*value
)
359 return value
->offset
;
362 set_value_offset (struct value
*value
, int offset
)
364 value
->offset
= offset
;
368 value_bitpos (struct value
*value
)
370 return value
->bitpos
;
373 set_value_bitpos (struct value
*value
, int bit
)
379 value_bitsize (struct value
*value
)
381 return value
->bitsize
;
384 set_value_bitsize (struct value
*value
, int bit
)
386 value
->bitsize
= bit
;
390 value_contents_raw (struct value
*value
)
392 allocate_value_contents (value
);
393 return value
->contents
+ value
->embedded_offset
;
397 value_contents_all_raw (struct value
*value
)
399 allocate_value_contents (value
);
400 return value
->contents
;
404 value_enclosing_type (struct value
*value
)
406 return value
->enclosing_type
;
410 value_contents_all (struct value
*value
)
413 value_fetch_lazy (value
);
414 return value
->contents
;
418 value_lazy (struct value
*value
)
424 set_value_lazy (struct value
*value
, int val
)
430 value_contents (struct value
*value
)
432 return value_contents_writeable (value
);
436 value_contents_writeable (struct value
*value
)
439 value_fetch_lazy (value
);
440 return value_contents_raw (value
);
443 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
444 this function is different from value_equal; in C the operator ==
445 can return 0 even if the two values being compared are equal. */
448 value_contents_equal (struct value
*val1
, struct value
*val2
)
454 type1
= check_typedef (value_type (val1
));
455 type2
= check_typedef (value_type (val2
));
456 len
= TYPE_LENGTH (type1
);
457 if (len
!= TYPE_LENGTH (type2
))
460 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
464 value_optimized_out (struct value
*value
)
466 return value
->optimized_out
;
470 set_value_optimized_out (struct value
*value
, int val
)
472 value
->optimized_out
= val
;
476 value_embedded_offset (struct value
*value
)
478 return value
->embedded_offset
;
482 set_value_embedded_offset (struct value
*value
, int val
)
484 value
->embedded_offset
= val
;
488 value_pointed_to_offset (struct value
*value
)
490 return value
->pointed_to_offset
;
494 set_value_pointed_to_offset (struct value
*value
, int val
)
496 value
->pointed_to_offset
= val
;
500 value_computed_funcs (struct value
*v
)
502 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
504 return v
->location
.computed
.funcs
;
508 value_computed_closure (struct value
*v
)
510 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
512 return v
->location
.computed
.closure
;
516 deprecated_value_lval_hack (struct value
*value
)
522 value_address (struct value
*value
)
524 if (value
->lval
== lval_internalvar
525 || value
->lval
== lval_internalvar_component
)
527 return value
->location
.address
+ value
->offset
;
531 value_raw_address (struct value
*value
)
533 if (value
->lval
== lval_internalvar
534 || value
->lval
== lval_internalvar_component
)
536 return value
->location
.address
;
540 set_value_address (struct value
*value
, CORE_ADDR addr
)
542 gdb_assert (value
->lval
!= lval_internalvar
543 && value
->lval
!= lval_internalvar_component
);
544 value
->location
.address
= addr
;
547 struct internalvar
**
548 deprecated_value_internalvar_hack (struct value
*value
)
550 return &value
->location
.internalvar
;
554 deprecated_value_frame_id_hack (struct value
*value
)
556 return &value
->frame_id
;
560 deprecated_value_regnum_hack (struct value
*value
)
562 return &value
->regnum
;
566 deprecated_value_modifiable (struct value
*value
)
568 return value
->modifiable
;
571 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
573 value
->modifiable
= modifiable
;
576 /* Return a mark in the value chain. All values allocated after the
577 mark is obtained (except for those released) are subject to being freed
578 if a subsequent value_free_to_mark is passed the mark. */
586 value_free (struct value
*val
)
590 if (VALUE_LVAL (val
) == lval_computed
)
592 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
594 if (funcs
->free_closure
)
595 funcs
->free_closure (val
);
598 xfree (val
->contents
);
603 /* Free all values allocated since MARK was obtained by value_mark
604 (except for those released). */
606 value_free_to_mark (struct value
*mark
)
611 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
619 /* Free all the values that have been allocated (except for those released).
620 Called after each command, successful or not. */
623 free_all_values (void)
628 for (val
= all_values
; val
; val
= next
)
637 /* Remove VAL from the chain all_values
638 so it will not be freed automatically. */
641 release_value (struct value
*val
)
645 if (all_values
== val
)
647 all_values
= val
->next
;
651 for (v
= all_values
; v
; v
= v
->next
)
661 /* Release all values up to mark */
663 value_release_to_mark (struct value
*mark
)
668 for (val
= next
= all_values
; next
; next
= next
->next
)
669 if (next
->next
== mark
)
671 all_values
= next
->next
;
679 /* Return a copy of the value ARG.
680 It contains the same contents, for same memory address,
681 but it's a different block of storage. */
684 value_copy (struct value
*arg
)
686 struct type
*encl_type
= value_enclosing_type (arg
);
689 if (value_lazy (arg
))
690 val
= allocate_value_lazy (encl_type
);
692 val
= allocate_value (encl_type
);
693 val
->type
= arg
->type
;
694 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
695 val
->location
= arg
->location
;
696 val
->offset
= arg
->offset
;
697 val
->bitpos
= arg
->bitpos
;
698 val
->bitsize
= arg
->bitsize
;
699 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
700 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
701 val
->lazy
= arg
->lazy
;
702 val
->optimized_out
= arg
->optimized_out
;
703 val
->embedded_offset
= value_embedded_offset (arg
);
704 val
->pointed_to_offset
= arg
->pointed_to_offset
;
705 val
->modifiable
= arg
->modifiable
;
706 if (!value_lazy (val
))
708 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
709 TYPE_LENGTH (value_enclosing_type (arg
)));
712 if (VALUE_LVAL (val
) == lval_computed
)
714 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
716 if (funcs
->copy_closure
)
717 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
723 set_value_component_location (struct value
*component
, struct value
*whole
)
725 if (VALUE_LVAL (whole
) == lval_internalvar
)
726 VALUE_LVAL (component
) = lval_internalvar_component
;
728 VALUE_LVAL (component
) = VALUE_LVAL (whole
);
730 component
->location
= whole
->location
;
731 if (VALUE_LVAL (whole
) == lval_computed
)
733 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
735 if (funcs
->copy_closure
)
736 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
741 /* Access to the value history. */
743 /* Record a new value in the value history.
744 Returns the absolute history index of the entry.
745 Result of -1 indicates the value was not saved; otherwise it is the
746 value history index of this new item. */
749 record_latest_value (struct value
*val
)
753 /* We don't want this value to have anything to do with the inferior anymore.
754 In particular, "set $1 = 50" should not affect the variable from which
755 the value was taken, and fast watchpoints should be able to assume that
756 a value on the value history never changes. */
757 if (value_lazy (val
))
758 value_fetch_lazy (val
);
759 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
760 from. This is a bit dubious, because then *&$1 does not just return $1
761 but the current contents of that location. c'est la vie... */
765 /* Here we treat value_history_count as origin-zero
766 and applying to the value being stored now. */
768 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
771 struct value_history_chunk
*new
772 = (struct value_history_chunk
*)
773 xmalloc (sizeof (struct value_history_chunk
));
774 memset (new->values
, 0, sizeof new->values
);
775 new->next
= value_history_chain
;
776 value_history_chain
= new;
779 value_history_chain
->values
[i
] = val
;
781 /* Now we regard value_history_count as origin-one
782 and applying to the value just stored. */
784 return ++value_history_count
;
787 /* Return a copy of the value in the history with sequence number NUM. */
790 access_value_history (int num
)
792 struct value_history_chunk
*chunk
;
797 absnum
+= value_history_count
;
802 error (_("The history is empty."));
804 error (_("There is only one value in the history."));
806 error (_("History does not go back to $$%d."), -num
);
808 if (absnum
> value_history_count
)
809 error (_("History has not yet reached $%d."), absnum
);
813 /* Now absnum is always absolute and origin zero. */
815 chunk
= value_history_chain
;
816 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
820 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
824 show_values (char *num_exp
, int from_tty
)
832 /* "show values +" should print from the stored position.
833 "show values <exp>" should print around value number <exp>. */
834 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
835 num
= parse_and_eval_long (num_exp
) - 5;
839 /* "show values" means print the last 10 values. */
840 num
= value_history_count
- 9;
846 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
848 struct value_print_options opts
;
849 val
= access_value_history (i
);
850 printf_filtered (("$%d = "), i
);
851 get_user_print_options (&opts
);
852 value_print (val
, gdb_stdout
, &opts
);
853 printf_filtered (("\n"));
856 /* The next "show values +" should start after what we just printed. */
859 /* Hitting just return after this command should do the same thing as
860 "show values +". If num_exp is null, this is unnecessary, since
861 "show values +" is not useful after "show values". */
862 if (from_tty
&& num_exp
)
869 /* Internal variables. These are variables within the debugger
870 that hold values assigned by debugger commands.
871 The user refers to them with a '$' prefix
872 that does not appear in the variable names stored internally. */
876 struct internalvar
*next
;
879 /* We support various different kinds of content of an internal variable.
880 enum internalvar_kind specifies the kind, and union internalvar_data
881 provides the data associated with this particular kind. */
883 enum internalvar_kind
885 /* The internal variable is empty. */
888 /* The value of the internal variable is provided directly as
889 a GDB value object. */
892 /* A fresh value is computed via a call-back routine on every
893 access to the internal variable. */
894 INTERNALVAR_MAKE_VALUE
,
896 /* The internal variable holds a GDB internal convenience function. */
897 INTERNALVAR_FUNCTION
,
899 /* The variable holds a simple scalar value. */
902 /* The variable holds a GDB-provided string. */
907 union internalvar_data
909 /* A value object used with INTERNALVAR_VALUE. */
912 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
913 internalvar_make_value make_value
;
915 /* The internal function used with INTERNALVAR_FUNCTION. */
918 struct internal_function
*function
;
919 /* True if this is the canonical name for the function. */
923 /* A scalar value used with INTERNALVAR_SCALAR. */
926 /* If type is non-NULL, it will be used as the type to generate
927 a value for this internal variable. If type is NULL, a default
928 integer type for the architecture is used. */
932 LONGEST l
; /* Used with TYPE_CODE_INT and NULL types. */
933 CORE_ADDR a
; /* Used with TYPE_CODE_PTR types. */
937 /* A string value used with INTERNALVAR_STRING. */
942 static struct internalvar
*internalvars
;
944 /* If the variable does not already exist create it and give it the value given.
945 If no value is given then the default is zero. */
947 init_if_undefined_command (char* args
, int from_tty
)
949 struct internalvar
* intvar
;
951 /* Parse the expression - this is taken from set_command(). */
952 struct expression
*expr
= parse_expression (args
);
953 register struct cleanup
*old_chain
=
954 make_cleanup (free_current_contents
, &expr
);
956 /* Validate the expression.
957 Was the expression an assignment?
958 Or even an expression at all? */
959 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
960 error (_("Init-if-undefined requires an assignment expression."));
962 /* Extract the variable from the parsed expression.
963 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
964 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
965 error (_("The first parameter to init-if-undefined should be a GDB variable."));
966 intvar
= expr
->elts
[2].internalvar
;
968 /* Only evaluate the expression if the lvalue is void.
969 This may still fail if the expresssion is invalid. */
970 if (intvar
->kind
== INTERNALVAR_VOID
)
971 evaluate_expression (expr
);
973 do_cleanups (old_chain
);
977 /* Look up an internal variable with name NAME. NAME should not
978 normally include a dollar sign.
980 If the specified internal variable does not exist,
981 the return value is NULL. */
984 lookup_only_internalvar (const char *name
)
986 struct internalvar
*var
;
988 for (var
= internalvars
; var
; var
= var
->next
)
989 if (strcmp (var
->name
, name
) == 0)
996 /* Create an internal variable with name NAME and with a void value.
997 NAME should not normally include a dollar sign. */
1000 create_internalvar (const char *name
)
1002 struct internalvar
*var
;
1003 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1004 var
->name
= concat (name
, (char *)NULL
);
1005 var
->kind
= INTERNALVAR_VOID
;
1006 var
->next
= internalvars
;
1011 /* Create an internal variable with name NAME and register FUN as the
1012 function that value_of_internalvar uses to create a value whenever
1013 this variable is referenced. NAME should not normally include a
1016 struct internalvar
*
1017 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1019 struct internalvar
*var
= create_internalvar (name
);
1020 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1021 var
->u
.make_value
= fun
;
1025 /* Look up an internal variable with name NAME. NAME should not
1026 normally include a dollar sign.
1028 If the specified internal variable does not exist,
1029 one is created, with a void value. */
1031 struct internalvar
*
1032 lookup_internalvar (const char *name
)
1034 struct internalvar
*var
;
1036 var
= lookup_only_internalvar (name
);
1040 return create_internalvar (name
);
1043 /* Return current value of internal variable VAR. For variables that
1044 are not inherently typed, use a value type appropriate for GDBARCH. */
1047 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1053 case INTERNALVAR_VOID
:
1054 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1057 case INTERNALVAR_FUNCTION
:
1058 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1061 case INTERNALVAR_SCALAR
:
1062 if (!var
->u
.scalar
.type
)
1063 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1064 var
->u
.scalar
.val
.l
);
1065 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1066 val
= value_from_longest (var
->u
.scalar
.type
, var
->u
.scalar
.val
.l
);
1067 else if (TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_PTR
)
1068 val
= value_from_pointer (var
->u
.scalar
.type
, var
->u
.scalar
.val
.a
);
1070 internal_error (__FILE__
, __LINE__
, "bad type");
1073 case INTERNALVAR_STRING
:
1074 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1075 builtin_type (gdbarch
)->builtin_char
);
1078 case INTERNALVAR_VALUE
:
1079 val
= value_copy (var
->u
.value
);
1080 if (value_lazy (val
))
1081 value_fetch_lazy (val
);
1084 case INTERNALVAR_MAKE_VALUE
:
1085 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1089 internal_error (__FILE__
, __LINE__
, "bad kind");
1092 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1093 on this value go back to affect the original internal variable.
1095 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1096 no underlying modifyable state in the internal variable.
1098 Likewise, if the variable's value is a computed lvalue, we want
1099 references to it to produce another computed lvalue, where
1100 references and assignments actually operate through the
1101 computed value's functions.
1103 This means that internal variables with computed values
1104 behave a little differently from other internal variables:
1105 assignments to them don't just replace the previous value
1106 altogether. At the moment, this seems like the behavior we
1109 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1110 && val
->lval
!= lval_computed
)
1112 VALUE_LVAL (val
) = lval_internalvar
;
1113 VALUE_INTERNALVAR (val
) = var
;
1120 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1124 case INTERNALVAR_SCALAR
:
1125 if (var
->u
.scalar
.type
== NULL
1126 || TYPE_CODE (var
->u
.scalar
.type
) == TYPE_CODE_INT
)
1128 *result
= var
->u
.scalar
.val
.l
;
1139 get_internalvar_function (struct internalvar
*var
,
1140 struct internal_function
**result
)
1144 case INTERNALVAR_FUNCTION
:
1145 *result
= var
->u
.fn
.function
;
1154 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1155 int bitsize
, struct value
*newval
)
1161 case INTERNALVAR_VALUE
:
1162 addr
= value_contents_writeable (var
->u
.value
);
1165 modify_field (addr
+ offset
,
1166 value_as_long (newval
), bitpos
, bitsize
);
1168 memcpy (addr
+ offset
, value_contents (newval
),
1169 TYPE_LENGTH (value_type (newval
)));
1173 /* We can never get a component of any other kind. */
1174 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1179 set_internalvar (struct internalvar
*var
, struct value
*val
)
1181 enum internalvar_kind new_kind
;
1182 union internalvar_data new_data
= { 0 };
1184 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1185 error (_("Cannot overwrite convenience function %s"), var
->name
);
1187 /* Prepare new contents. */
1188 switch (TYPE_CODE (check_typedef (value_type (val
))))
1190 case TYPE_CODE_VOID
:
1191 new_kind
= INTERNALVAR_VOID
;
1194 case TYPE_CODE_INTERNAL_FUNCTION
:
1195 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1196 new_kind
= INTERNALVAR_FUNCTION
;
1197 get_internalvar_function (VALUE_INTERNALVAR (val
),
1198 &new_data
.fn
.function
);
1199 /* Copies created here are never canonical. */
1203 new_kind
= INTERNALVAR_SCALAR
;
1204 new_data
.scalar
.type
= value_type (val
);
1205 new_data
.scalar
.val
.l
= value_as_long (val
);
1209 new_kind
= INTERNALVAR_SCALAR
;
1210 new_data
.scalar
.type
= value_type (val
);
1211 new_data
.scalar
.val
.a
= value_as_address (val
);
1215 new_kind
= INTERNALVAR_VALUE
;
1216 new_data
.value
= value_copy (val
);
1217 new_data
.value
->modifiable
= 1;
1219 /* Force the value to be fetched from the target now, to avoid problems
1220 later when this internalvar is referenced and the target is gone or
1222 if (value_lazy (new_data
.value
))
1223 value_fetch_lazy (new_data
.value
);
1225 /* Release the value from the value chain to prevent it from being
1226 deleted by free_all_values. From here on this function should not
1227 call error () until new_data is installed into the var->u to avoid
1229 release_value (new_data
.value
);
1233 /* Clean up old contents. */
1234 clear_internalvar (var
);
1237 var
->kind
= new_kind
;
1239 /* End code which must not call error(). */
1243 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1245 /* Clean up old contents. */
1246 clear_internalvar (var
);
1248 var
->kind
= INTERNALVAR_SCALAR
;
1249 var
->u
.scalar
.type
= NULL
;
1250 var
->u
.scalar
.val
.l
= l
;
1254 set_internalvar_string (struct internalvar
*var
, const char *string
)
1256 /* Clean up old contents. */
1257 clear_internalvar (var
);
1259 var
->kind
= INTERNALVAR_STRING
;
1260 var
->u
.string
= xstrdup (string
);
1264 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1266 /* Clean up old contents. */
1267 clear_internalvar (var
);
1269 var
->kind
= INTERNALVAR_FUNCTION
;
1270 var
->u
.fn
.function
= f
;
1271 var
->u
.fn
.canonical
= 1;
1272 /* Variables installed here are always the canonical version. */
1276 clear_internalvar (struct internalvar
*var
)
1278 /* Clean up old contents. */
1281 case INTERNALVAR_VALUE
:
1282 value_free (var
->u
.value
);
1285 case INTERNALVAR_STRING
:
1286 xfree (var
->u
.string
);
1293 /* Reset to void kind. */
1294 var
->kind
= INTERNALVAR_VOID
;
1298 internalvar_name (struct internalvar
*var
)
1303 static struct internal_function
*
1304 create_internal_function (const char *name
,
1305 internal_function_fn handler
, void *cookie
)
1307 struct internal_function
*ifn
= XNEW (struct internal_function
);
1308 ifn
->name
= xstrdup (name
);
1309 ifn
->handler
= handler
;
1310 ifn
->cookie
= cookie
;
1315 value_internal_function_name (struct value
*val
)
1317 struct internal_function
*ifn
;
1320 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1321 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1322 gdb_assert (result
);
1328 call_internal_function (struct value
*func
, int argc
, struct value
**argv
)
1330 struct internal_function
*ifn
;
1333 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1334 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1335 gdb_assert (result
);
1337 return (*ifn
->handler
) (ifn
->cookie
, argc
, argv
);
1340 /* The 'function' command. This does nothing -- it is just a
1341 placeholder to let "help function NAME" work. This is also used as
1342 the implementation of the sub-command that is created when
1343 registering an internal function. */
1345 function_command (char *command
, int from_tty
)
1350 /* Clean up if an internal function's command is destroyed. */
1352 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1358 /* Add a new internal function. NAME is the name of the function; DOC
1359 is a documentation string describing the function. HANDLER is
1360 called when the function is invoked. COOKIE is an arbitrary
1361 pointer which is passed to HANDLER and is intended for "user
1364 add_internal_function (const char *name
, const char *doc
,
1365 internal_function_fn handler
, void *cookie
)
1367 struct cmd_list_element
*cmd
;
1368 struct internal_function
*ifn
;
1369 struct internalvar
*var
= lookup_internalvar (name
);
1371 ifn
= create_internal_function (name
, handler
, cookie
);
1372 set_internalvar_function (var
, ifn
);
1374 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1376 cmd
->destroyer
= function_destroyer
;
1379 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1380 prevent cycles / duplicates. */
1383 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1384 htab_t copied_types
)
1386 if (TYPE_OBJFILE (value
->type
) == objfile
)
1387 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1389 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1390 value
->enclosing_type
= copy_type_recursive (objfile
,
1391 value
->enclosing_type
,
1395 /* Likewise for internal variable VAR. */
1398 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1399 htab_t copied_types
)
1403 case INTERNALVAR_SCALAR
:
1404 if (var
->u
.scalar
.type
&& TYPE_OBJFILE (var
->u
.scalar
.type
) == objfile
)
1406 = copy_type_recursive (objfile
, var
->u
.scalar
.type
, copied_types
);
1409 case INTERNALVAR_VALUE
:
1410 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1415 /* Update the internal variables and value history when OBJFILE is
1416 discarded; we must copy the types out of the objfile. New global types
1417 will be created for every convenience variable which currently points to
1418 this objfile's types, and the convenience variables will be adjusted to
1419 use the new global types. */
1422 preserve_values (struct objfile
*objfile
)
1424 htab_t copied_types
;
1425 struct value_history_chunk
*cur
;
1426 struct internalvar
*var
;
1430 /* Create the hash table. We allocate on the objfile's obstack, since
1431 it is soon to be deleted. */
1432 copied_types
= create_copied_types_hash (objfile
);
1434 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1435 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1437 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1439 for (var
= internalvars
; var
; var
= var
->next
)
1440 preserve_one_internalvar (var
, objfile
, copied_types
);
1442 for (val
= values_in_python
; val
; val
= val
->next
)
1443 preserve_one_value (val
, objfile
, copied_types
);
1445 htab_delete (copied_types
);
1449 show_convenience (char *ignore
, int from_tty
)
1451 struct gdbarch
*gdbarch
= current_gdbarch
;
1452 struct internalvar
*var
;
1454 struct value_print_options opts
;
1456 get_user_print_options (&opts
);
1457 for (var
= internalvars
; var
; var
= var
->next
)
1463 printf_filtered (("$%s = "), var
->name
);
1464 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1466 printf_filtered (("\n"));
1469 printf_unfiltered (_("\
1470 No debugger convenience variables now defined.\n\
1471 Convenience variables have names starting with \"$\";\n\
1472 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1475 /* Extract a value as a C number (either long or double).
1476 Knows how to convert fixed values to double, or
1477 floating values to long.
1478 Does not deallocate the value. */
1481 value_as_long (struct value
*val
)
1483 /* This coerces arrays and functions, which is necessary (e.g.
1484 in disassemble_command). It also dereferences references, which
1485 I suspect is the most logical thing to do. */
1486 val
= coerce_array (val
);
1487 return unpack_long (value_type (val
), value_contents (val
));
1491 value_as_double (struct value
*val
)
1496 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1498 error (_("Invalid floating value found in program."));
1502 /* Extract a value as a C pointer. Does not deallocate the value.
1503 Note that val's type may not actually be a pointer; value_as_long
1504 handles all the cases. */
1506 value_as_address (struct value
*val
)
1508 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1509 whether we want this to be true eventually. */
1511 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1512 non-address (e.g. argument to "signal", "info break", etc.), or
1513 for pointers to char, in which the low bits *are* significant. */
1514 return gdbarch_addr_bits_remove (current_gdbarch
, value_as_long (val
));
1517 /* There are several targets (IA-64, PowerPC, and others) which
1518 don't represent pointers to functions as simply the address of
1519 the function's entry point. For example, on the IA-64, a
1520 function pointer points to a two-word descriptor, generated by
1521 the linker, which contains the function's entry point, and the
1522 value the IA-64 "global pointer" register should have --- to
1523 support position-independent code. The linker generates
1524 descriptors only for those functions whose addresses are taken.
1526 On such targets, it's difficult for GDB to convert an arbitrary
1527 function address into a function pointer; it has to either find
1528 an existing descriptor for that function, or call malloc and
1529 build its own. On some targets, it is impossible for GDB to
1530 build a descriptor at all: the descriptor must contain a jump
1531 instruction; data memory cannot be executed; and code memory
1534 Upon entry to this function, if VAL is a value of type `function'
1535 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1536 value_address (val) is the address of the function. This is what
1537 you'll get if you evaluate an expression like `main'. The call
1538 to COERCE_ARRAY below actually does all the usual unary
1539 conversions, which includes converting values of type `function'
1540 to `pointer to function'. This is the challenging conversion
1541 discussed above. Then, `unpack_long' will convert that pointer
1542 back into an address.
1544 So, suppose the user types `disassemble foo' on an architecture
1545 with a strange function pointer representation, on which GDB
1546 cannot build its own descriptors, and suppose further that `foo'
1547 has no linker-built descriptor. The address->pointer conversion
1548 will signal an error and prevent the command from running, even
1549 though the next step would have been to convert the pointer
1550 directly back into the same address.
1552 The following shortcut avoids this whole mess. If VAL is a
1553 function, just return its address directly. */
1554 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1555 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1556 return value_address (val
);
1558 val
= coerce_array (val
);
1560 /* Some architectures (e.g. Harvard), map instruction and data
1561 addresses onto a single large unified address space. For
1562 instance: An architecture may consider a large integer in the
1563 range 0x10000000 .. 0x1000ffff to already represent a data
1564 addresses (hence not need a pointer to address conversion) while
1565 a small integer would still need to be converted integer to
1566 pointer to address. Just assume such architectures handle all
1567 integer conversions in a single function. */
1571 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1572 must admonish GDB hackers to make sure its behavior matches the
1573 compiler's, whenever possible.
1575 In general, I think GDB should evaluate expressions the same way
1576 the compiler does. When the user copies an expression out of
1577 their source code and hands it to a `print' command, they should
1578 get the same value the compiler would have computed. Any
1579 deviation from this rule can cause major confusion and annoyance,
1580 and needs to be justified carefully. In other words, GDB doesn't
1581 really have the freedom to do these conversions in clever and
1584 AndrewC pointed out that users aren't complaining about how GDB
1585 casts integers to pointers; they are complaining that they can't
1586 take an address from a disassembly listing and give it to `x/i'.
1587 This is certainly important.
1589 Adding an architecture method like integer_to_address() certainly
1590 makes it possible for GDB to "get it right" in all circumstances
1591 --- the target has complete control over how things get done, so
1592 people can Do The Right Thing for their target without breaking
1593 anyone else. The standard doesn't specify how integers get
1594 converted to pointers; usually, the ABI doesn't either, but
1595 ABI-specific code is a more reasonable place to handle it. */
1597 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1598 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1599 && gdbarch_integer_to_address_p (current_gdbarch
))
1600 return gdbarch_integer_to_address (current_gdbarch
, value_type (val
),
1601 value_contents (val
));
1603 return unpack_long (value_type (val
), value_contents (val
));
1607 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1608 as a long, or as a double, assuming the raw data is described
1609 by type TYPE. Knows how to convert different sizes of values
1610 and can convert between fixed and floating point. We don't assume
1611 any alignment for the raw data. Return value is in host byte order.
1613 If you want functions and arrays to be coerced to pointers, and
1614 references to be dereferenced, call value_as_long() instead.
1616 C++: It is assumed that the front-end has taken care of
1617 all matters concerning pointers to members. A pointer
1618 to member which reaches here is considered to be equivalent
1619 to an INT (or some size). After all, it is only an offset. */
1622 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1624 enum type_code code
= TYPE_CODE (type
);
1625 int len
= TYPE_LENGTH (type
);
1626 int nosign
= TYPE_UNSIGNED (type
);
1630 case TYPE_CODE_TYPEDEF
:
1631 return unpack_long (check_typedef (type
), valaddr
);
1632 case TYPE_CODE_ENUM
:
1633 case TYPE_CODE_FLAGS
:
1634 case TYPE_CODE_BOOL
:
1636 case TYPE_CODE_CHAR
:
1637 case TYPE_CODE_RANGE
:
1638 case TYPE_CODE_MEMBERPTR
:
1640 return extract_unsigned_integer (valaddr
, len
);
1642 return extract_signed_integer (valaddr
, len
);
1645 return extract_typed_floating (valaddr
, type
);
1647 case TYPE_CODE_DECFLOAT
:
1648 /* libdecnumber has a function to convert from decimal to integer, but
1649 it doesn't work when the decimal number has a fractional part. */
1650 return decimal_to_doublest (valaddr
, len
);
1654 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1655 whether we want this to be true eventually. */
1656 return extract_typed_address (valaddr
, type
);
1659 error (_("Value can't be converted to integer."));
1661 return 0; /* Placate lint. */
1664 /* Return a double value from the specified type and address.
1665 INVP points to an int which is set to 0 for valid value,
1666 1 for invalid value (bad float format). In either case,
1667 the returned double is OK to use. Argument is in target
1668 format, result is in host format. */
1671 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1673 enum type_code code
;
1677 *invp
= 0; /* Assume valid. */
1678 CHECK_TYPEDEF (type
);
1679 code
= TYPE_CODE (type
);
1680 len
= TYPE_LENGTH (type
);
1681 nosign
= TYPE_UNSIGNED (type
);
1682 if (code
== TYPE_CODE_FLT
)
1684 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1685 floating-point value was valid (using the macro
1686 INVALID_FLOAT). That test/macro have been removed.
1688 It turns out that only the VAX defined this macro and then
1689 only in a non-portable way. Fixing the portability problem
1690 wouldn't help since the VAX floating-point code is also badly
1691 bit-rotten. The target needs to add definitions for the
1692 methods gdbarch_float_format and gdbarch_double_format - these
1693 exactly describe the target floating-point format. The
1694 problem here is that the corresponding floatformat_vax_f and
1695 floatformat_vax_d values these methods should be set to are
1696 also not defined either. Oops!
1698 Hopefully someone will add both the missing floatformat
1699 definitions and the new cases for floatformat_is_valid (). */
1701 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1707 return extract_typed_floating (valaddr
, type
);
1709 else if (code
== TYPE_CODE_DECFLOAT
)
1710 return decimal_to_doublest (valaddr
, len
);
1713 /* Unsigned -- be sure we compensate for signed LONGEST. */
1714 return (ULONGEST
) unpack_long (type
, valaddr
);
1718 /* Signed -- we are OK with unpack_long. */
1719 return unpack_long (type
, valaddr
);
1723 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1724 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1725 We don't assume any alignment for the raw data. Return value is in
1728 If you want functions and arrays to be coerced to pointers, and
1729 references to be dereferenced, call value_as_address() instead.
1731 C++: It is assumed that the front-end has taken care of
1732 all matters concerning pointers to members. A pointer
1733 to member which reaches here is considered to be equivalent
1734 to an INT (or some size). After all, it is only an offset. */
1737 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1739 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1740 whether we want this to be true eventually. */
1741 return unpack_long (type
, valaddr
);
1745 /* Get the value of the FIELDN'th field (which must be static) of
1746 TYPE. Return NULL if the field doesn't exist or has been
1750 value_static_field (struct type
*type
, int fieldno
)
1752 struct value
*retval
;
1754 if (TYPE_FIELD_LOC_KIND (type
, fieldno
) == FIELD_LOC_KIND_PHYSADDR
)
1756 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1757 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1761 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1762 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1765 /* With some compilers, e.g. HP aCC, static data members are reported
1766 as non-debuggable symbols */
1767 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
, NULL
, NULL
);
1772 retval
= value_at (TYPE_FIELD_TYPE (type
, fieldno
),
1773 SYMBOL_VALUE_ADDRESS (msym
));
1778 /* SYM should never have a SYMBOL_CLASS which will require
1779 read_var_value to use the FRAME parameter. */
1780 if (symbol_read_needs_frame (sym
))
1781 warning (_("static field's value depends on the current "
1782 "frame - bad debug info?"));
1783 retval
= read_var_value (sym
, NULL
);
1785 if (retval
&& VALUE_LVAL (retval
) == lval_memory
)
1786 SET_FIELD_PHYSADDR (TYPE_FIELD (type
, fieldno
),
1787 value_address (retval
));
1792 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1793 You have to be careful here, since the size of the data area for the value
1794 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1795 than the old enclosing type, you have to allocate more space for the data.
1796 The return value is a pointer to the new version of this value structure. */
1799 value_change_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1801 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1803 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1805 val
->enclosing_type
= new_encl_type
;
1809 /* Given a value ARG1 (offset by OFFSET bytes)
1810 of a struct or union type ARG_TYPE,
1811 extract and return the value of one of its (non-static) fields.
1812 FIELDNO says which field. */
1815 value_primitive_field (struct value
*arg1
, int offset
,
1816 int fieldno
, struct type
*arg_type
)
1821 CHECK_TYPEDEF (arg_type
);
1822 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1824 /* Handle packed fields */
1826 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1828 v
= value_from_longest (type
,
1829 unpack_field_as_long (arg_type
,
1830 value_contents (arg1
)
1833 v
->bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
) % 8;
1834 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
1835 v
->offset
= value_offset (arg1
) + offset
1836 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1838 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
1840 /* This field is actually a base subobject, so preserve the
1841 entire object's contents for later references to virtual
1844 /* Lazy register values with offsets are not supported. */
1845 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1846 value_fetch_lazy (arg1
);
1848 if (value_lazy (arg1
))
1849 v
= allocate_value_lazy (value_enclosing_type (arg1
));
1852 v
= allocate_value (value_enclosing_type (arg1
));
1853 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
1854 TYPE_LENGTH (value_enclosing_type (arg1
)));
1857 v
->offset
= value_offset (arg1
);
1858 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
1859 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
1863 /* Plain old data member */
1864 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
1866 /* Lazy register values with offsets are not supported. */
1867 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
1868 value_fetch_lazy (arg1
);
1870 if (value_lazy (arg1
))
1871 v
= allocate_value_lazy (type
);
1874 v
= allocate_value (type
);
1875 memcpy (value_contents_raw (v
),
1876 value_contents_raw (arg1
) + offset
,
1877 TYPE_LENGTH (type
));
1879 v
->offset
= (value_offset (arg1
) + offset
1880 + value_embedded_offset (arg1
));
1882 set_value_component_location (v
, arg1
);
1883 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
1884 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
1888 /* Given a value ARG1 of a struct or union type,
1889 extract and return the value of one of its (non-static) fields.
1890 FIELDNO says which field. */
1893 value_field (struct value
*arg1
, int fieldno
)
1895 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
1898 /* Return a non-virtual function as a value.
1899 F is the list of member functions which contains the desired method.
1900 J is an index into F which provides the desired method.
1902 We only use the symbol for its address, so be happy with either a
1903 full symbol or a minimal symbol.
1907 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
1911 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
1912 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
1914 struct minimal_symbol
*msym
;
1916 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
1923 gdb_assert (sym
== NULL
);
1924 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
1929 v
= allocate_value (ftype
);
1932 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
1936 /* The minimal symbol might point to a function descriptor;
1937 resolve it to the actual code address instead. */
1938 struct objfile
*objfile
= msymbol_objfile (msym
);
1939 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
1941 set_value_address (v
,
1942 gdbarch_convert_from_func_ptr_addr
1943 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
1948 if (type
!= value_type (*arg1p
))
1949 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
1950 value_addr (*arg1p
)));
1952 /* Move the `this' pointer according to the offset.
1953 VALUE_OFFSET (*arg1p) += offset;
1961 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
1964 Extracting bits depends on endianness of the machine. Compute the
1965 number of least significant bits to discard. For big endian machines,
1966 we compute the total number of bits in the anonymous object, subtract
1967 off the bit count from the MSB of the object to the MSB of the
1968 bitfield, then the size of the bitfield, which leaves the LSB discard
1969 count. For little endian machines, the discard count is simply the
1970 number of bits from the LSB of the anonymous object to the LSB of the
1973 If the field is signed, we also do sign extension. */
1976 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
1980 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
1981 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
1983 struct type
*field_type
;
1985 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8, sizeof (val
));
1986 field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
1987 CHECK_TYPEDEF (field_type
);
1989 /* Extract bits. See comment above. */
1991 if (gdbarch_bits_big_endian (current_gdbarch
))
1992 lsbcount
= (sizeof val
* 8 - bitpos
% 8 - bitsize
);
1994 lsbcount
= (bitpos
% 8);
1997 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
1998 If the field is signed, and is negative, then sign extend. */
2000 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2002 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2004 if (!TYPE_UNSIGNED (field_type
))
2006 if (val
& (valmask
^ (valmask
>> 1)))
2015 /* Modify the value of a bitfield. ADDR points to a block of memory in
2016 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2017 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2018 indicate which bits (in target bit order) comprise the bitfield.
2019 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS+BITSIZE <= lbits, and
2020 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2023 modify_field (gdb_byte
*addr
, LONGEST fieldval
, int bitpos
, int bitsize
)
2026 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2028 /* If a negative fieldval fits in the field in question, chop
2029 off the sign extension bits. */
2030 if ((~fieldval
& ~(mask
>> 1)) == 0)
2033 /* Warn if value is too big to fit in the field in question. */
2034 if (0 != (fieldval
& ~mask
))
2036 /* FIXME: would like to include fieldval in the message, but
2037 we don't have a sprintf_longest. */
2038 warning (_("Value does not fit in %d bits."), bitsize
);
2040 /* Truncate it, otherwise adjoining fields may be corrupted. */
2044 oword
= extract_unsigned_integer (addr
, sizeof oword
);
2046 /* Shifting for bit field depends on endianness of the target machine. */
2047 if (gdbarch_bits_big_endian (current_gdbarch
))
2048 bitpos
= sizeof (oword
) * 8 - bitpos
- bitsize
;
2050 oword
&= ~(mask
<< bitpos
);
2051 oword
|= fieldval
<< bitpos
;
2053 store_unsigned_integer (addr
, sizeof oword
, oword
);
2056 /* Pack NUM into BUF using a target format of TYPE. */
2059 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2063 type
= check_typedef (type
);
2064 len
= TYPE_LENGTH (type
);
2066 switch (TYPE_CODE (type
))
2069 case TYPE_CODE_CHAR
:
2070 case TYPE_CODE_ENUM
:
2071 case TYPE_CODE_FLAGS
:
2072 case TYPE_CODE_BOOL
:
2073 case TYPE_CODE_RANGE
:
2074 case TYPE_CODE_MEMBERPTR
:
2075 store_signed_integer (buf
, len
, num
);
2080 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2084 error (_("Unexpected type (%d) encountered for integer constant."),
2090 /* Convert C numbers into newly allocated values. */
2093 value_from_longest (struct type
*type
, LONGEST num
)
2095 struct value
*val
= allocate_value (type
);
2097 pack_long (value_contents_raw (val
), type
, num
);
2103 /* Create a value representing a pointer of type TYPE to the address
2106 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2108 struct value
*val
= allocate_value (type
);
2109 store_typed_address (value_contents_raw (val
), type
, addr
);
2114 /* Create a value of type TYPE whose contents come from VALADDR, if it
2115 is non-null, and whose memory address (in the inferior) is
2119 value_from_contents_and_address (struct type
*type
,
2120 const gdb_byte
*valaddr
,
2123 struct value
*v
= allocate_value (type
);
2124 if (valaddr
== NULL
)
2125 set_value_lazy (v
, 1);
2127 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2128 set_value_address (v
, address
);
2129 VALUE_LVAL (v
) = lval_memory
;
2134 value_from_double (struct type
*type
, DOUBLEST num
)
2136 struct value
*val
= allocate_value (type
);
2137 struct type
*base_type
= check_typedef (type
);
2138 enum type_code code
= TYPE_CODE (base_type
);
2139 int len
= TYPE_LENGTH (base_type
);
2141 if (code
== TYPE_CODE_FLT
)
2143 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2146 error (_("Unexpected type encountered for floating constant."));
2152 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2154 struct value
*val
= allocate_value (type
);
2156 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2162 coerce_ref (struct value
*arg
)
2164 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2165 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2166 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2167 unpack_pointer (value_type (arg
),
2168 value_contents (arg
)));
2173 coerce_array (struct value
*arg
)
2177 arg
= coerce_ref (arg
);
2178 type
= check_typedef (value_type (arg
));
2180 switch (TYPE_CODE (type
))
2182 case TYPE_CODE_ARRAY
:
2183 if (current_language
->c_style_arrays
)
2184 arg
= value_coerce_array (arg
);
2186 case TYPE_CODE_FUNC
:
2187 arg
= value_coerce_function (arg
);
2194 /* Return true if the function returning the specified type is using
2195 the convention of returning structures in memory (passing in the
2196 address as a hidden first parameter). */
2199 using_struct_return (struct gdbarch
*gdbarch
,
2200 struct type
*func_type
, struct type
*value_type
)
2202 enum type_code code
= TYPE_CODE (value_type
);
2204 if (code
== TYPE_CODE_ERROR
)
2205 error (_("Function return type unknown."));
2207 if (code
== TYPE_CODE_VOID
)
2208 /* A void return value is never in memory. See also corresponding
2209 code in "print_return_value". */
2212 /* Probe the architecture for the return-value convention. */
2213 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2215 != RETURN_VALUE_REGISTER_CONVENTION
);
2218 /* Set the initialized field in a value struct. */
2221 set_value_initialized (struct value
*val
, int status
)
2223 val
->initialized
= status
;
2226 /* Return the initialized field in a value struct. */
2229 value_initialized (struct value
*val
)
2231 return val
->initialized
;
2235 _initialize_values (void)
2237 add_cmd ("convenience", no_class
, show_convenience
, _("\
2238 Debugger convenience (\"$foo\") variables.\n\
2239 These variables are created when you assign them values;\n\
2240 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2242 A few convenience variables are given values automatically:\n\
2243 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2244 \"$__\" holds the contents of the last address examined with \"x\"."),
2247 add_cmd ("values", no_class
, show_values
,
2248 _("Elements of value history around item number IDX (or last ten)."),
2251 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2252 Initialize a convenience variable if necessary.\n\
2253 init-if-undefined VARIABLE = EXPRESSION\n\
2254 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2255 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2256 VARIABLE is already initialized."));
2258 add_prefix_cmd ("function", no_class
, function_command
, _("\
2259 Placeholder command for showing help on convenience functions."),
2260 &functionlist
, "function ", 0, &cmdlist
);