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, 2010 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 "arch-utils.h"
24 #include "gdb_string.h"
35 #include "gdb_assert.h"
41 #include "cli/cli-decode.h"
43 #include "python/python.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler
;
60 /* User data for the handler. */
64 static struct cmd_list_element
*functionlist
;
68 /* Type of value; either not an lval, or one of the various
69 different possible kinds of lval. */
72 /* Is it modifiable? Only relevant if lval != not_lval. */
75 /* Location of value (if lval). */
78 /* If lval == lval_memory, this is the address in the inferior.
79 If lval == lval_register, this is the byte offset into the
80 registers structure. */
83 /* Pointer to internal variable. */
84 struct internalvar
*internalvar
;
86 /* If lval == lval_computed, this is a set of function pointers
87 to use to access and describe the value, and a closure pointer
91 struct lval_funcs
*funcs
; /* Functions to call. */
92 void *closure
; /* Closure for those functions to use. */
96 /* Describes offset of a value within lval of a structure in bytes.
97 If lval == lval_memory, this is an offset to the address. If
98 lval == lval_register, this is a further offset from
99 location.address within the registers structure. Note also the
100 member embedded_offset below. */
103 /* Only used for bitfields; number of bits contained in them. */
106 /* Only used for bitfields; position of start of field. For
107 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
108 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
111 /* Only used for bitfields; the containing value. This allows a
112 single read from the target when displaying multiple
114 struct value
*parent
;
116 /* Frame register value is relative to. This will be described in
117 the lval enum above as "lval_register". */
118 struct frame_id frame_id
;
120 /* Type of the value. */
123 /* If a value represents a C++ object, then the `type' field gives
124 the object's compile-time type. If the object actually belongs
125 to some class derived from `type', perhaps with other base
126 classes and additional members, then `type' is just a subobject
127 of the real thing, and the full object is probably larger than
128 `type' would suggest.
130 If `type' is a dynamic class (i.e. one with a vtable), then GDB
131 can actually determine the object's run-time type by looking at
132 the run-time type information in the vtable. When this
133 information is available, we may elect to read in the entire
134 object, for several reasons:
136 - When printing the value, the user would probably rather see the
137 full object, not just the limited portion apparent from the
140 - If `type' has virtual base classes, then even printing `type'
141 alone may require reaching outside the `type' portion of the
142 object to wherever the virtual base class has been stored.
144 When we store the entire object, `enclosing_type' is the run-time
145 type -- the complete object -- and `embedded_offset' is the
146 offset of `type' within that larger type, in bytes. The
147 value_contents() macro takes `embedded_offset' into account, so
148 most GDB code continues to see the `type' portion of the value,
149 just as the inferior would.
151 If `type' is a pointer to an object, then `enclosing_type' is a
152 pointer to the object's run-time type, and `pointed_to_offset' is
153 the offset in bytes from the full object to the pointed-to object
154 -- that is, the value `embedded_offset' would have if we followed
155 the pointer and fetched the complete object. (I don't really see
156 the point. Why not just determine the run-time type when you
157 indirect, and avoid the special case? The contents don't matter
158 until you indirect anyway.)
160 If we're not doing anything fancy, `enclosing_type' is equal to
161 `type', and `embedded_offset' is zero, so everything works
163 struct type
*enclosing_type
;
165 int pointed_to_offset
;
167 /* Values are stored in a chain, so that they can be deleted easily
168 over calls to the inferior. Values assigned to internal
169 variables, put into the value history or exposed to Python are
170 taken off this list. */
173 /* Register number if the value is from a register. */
176 /* If zero, contents of this value are in the contents field. If
177 nonzero, contents are in inferior. If the lval field is lval_memory,
178 the contents are in inferior memory at location.address plus offset.
179 The lval field may also be lval_register.
181 WARNING: This field is used by the code which handles watchpoints
182 (see breakpoint.c) to decide whether a particular value can be
183 watched by hardware watchpoints. If the lazy flag is set for
184 some member of a value chain, it is assumed that this member of
185 the chain doesn't need to be watched as part of watching the
186 value itself. This is how GDB avoids watching the entire struct
187 or array when the user wants to watch a single struct member or
188 array element. If you ever change the way lazy flag is set and
189 reset, be sure to consider this use as well! */
192 /* If nonzero, this is the value of a variable which does not
193 actually exist in the program. */
196 /* If value is a variable, is it initialized or not. */
199 /* If value is from the stack. If this is set, read_stack will be
200 used instead of read_memory to enable extra caching. */
203 /* Actual contents of the value. Target byte-order. NULL or not
204 valid if lazy is nonzero. */
207 /* The number of references to this value. When a value is created,
208 the value chain holds a reference, so REFERENCE_COUNT is 1. If
209 release_value is called, this value is removed from the chain but
210 the caller of release_value now has a reference to this value.
211 The caller must arrange for a call to value_free later. */
215 /* Prototypes for local functions. */
217 static void show_values (char *, int);
219 static void show_convenience (char *, int);
222 /* The value-history records all the values printed
223 by print commands during this session. Each chunk
224 records 60 consecutive values. The first chunk on
225 the chain records the most recent values.
226 The total number of values is in value_history_count. */
228 #define VALUE_HISTORY_CHUNK 60
230 struct value_history_chunk
232 struct value_history_chunk
*next
;
233 struct value
*values
[VALUE_HISTORY_CHUNK
];
236 /* Chain of chunks now in use. */
238 static struct value_history_chunk
*value_history_chain
;
240 static int value_history_count
; /* Abs number of last entry stored */
243 /* List of all value objects currently allocated
244 (except for those released by calls to release_value)
245 This is so they can be freed after each command. */
247 static struct value
*all_values
;
249 /* Allocate a lazy value for type TYPE. Its actual content is
250 "lazily" allocated too: the content field of the return value is
251 NULL; it will be allocated when it is fetched from the target. */
254 allocate_value_lazy (struct type
*type
)
258 /* Call check_typedef on our type to make sure that, if TYPE
259 is a TYPE_CODE_TYPEDEF, its length is set to the length
260 of the target type instead of zero. However, we do not
261 replace the typedef type by the target type, because we want
262 to keep the typedef in order to be able to set the VAL's type
263 description correctly. */
264 check_typedef (type
);
266 val
= (struct value
*) xzalloc (sizeof (struct value
));
267 val
->contents
= NULL
;
268 val
->next
= all_values
;
271 val
->enclosing_type
= type
;
272 VALUE_LVAL (val
) = not_lval
;
273 val
->location
.address
= 0;
274 VALUE_FRAME_ID (val
) = null_frame_id
;
278 VALUE_REGNUM (val
) = -1;
280 val
->optimized_out
= 0;
281 val
->embedded_offset
= 0;
282 val
->pointed_to_offset
= 0;
284 val
->initialized
= 1; /* Default to initialized. */
286 /* Values start out on the all_values chain. */
287 val
->reference_count
= 1;
292 /* Allocate the contents of VAL if it has not been allocated yet. */
295 allocate_value_contents (struct value
*val
)
298 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
301 /* Allocate a value and its contents for type TYPE. */
304 allocate_value (struct type
*type
)
306 struct value
*val
= allocate_value_lazy (type
);
308 allocate_value_contents (val
);
313 /* Allocate a value that has the correct length
314 for COUNT repetitions of type TYPE. */
317 allocate_repeat_value (struct type
*type
, int count
)
319 int low_bound
= current_language
->string_lower_bound
; /* ??? */
320 /* FIXME-type-allocation: need a way to free this type when we are
322 struct type
*array_type
323 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
325 return allocate_value (array_type
);
329 allocate_computed_value (struct type
*type
,
330 struct lval_funcs
*funcs
,
333 struct value
*v
= allocate_value (type
);
335 VALUE_LVAL (v
) = lval_computed
;
336 v
->location
.computed
.funcs
= funcs
;
337 v
->location
.computed
.closure
= closure
;
338 set_value_lazy (v
, 1);
343 /* Accessor methods. */
346 value_next (struct value
*value
)
352 value_type (const struct value
*value
)
357 deprecated_set_value_type (struct value
*value
, struct type
*type
)
363 value_offset (const struct value
*value
)
365 return value
->offset
;
368 set_value_offset (struct value
*value
, int offset
)
370 value
->offset
= offset
;
374 value_bitpos (const struct value
*value
)
376 return value
->bitpos
;
379 set_value_bitpos (struct value
*value
, int bit
)
385 value_bitsize (const struct value
*value
)
387 return value
->bitsize
;
390 set_value_bitsize (struct value
*value
, int bit
)
392 value
->bitsize
= bit
;
396 value_parent (struct value
*value
)
398 return value
->parent
;
402 value_contents_raw (struct value
*value
)
404 allocate_value_contents (value
);
405 return value
->contents
+ value
->embedded_offset
;
409 value_contents_all_raw (struct value
*value
)
411 allocate_value_contents (value
);
412 return value
->contents
;
416 value_enclosing_type (struct value
*value
)
418 return value
->enclosing_type
;
422 require_not_optimized_out (struct value
*value
)
424 if (value
->optimized_out
)
425 error (_("value has been optimized out"));
429 value_contents_for_printing (struct value
*value
)
432 value_fetch_lazy (value
);
433 return value
->contents
;
437 value_contents_all (struct value
*value
)
439 const gdb_byte
*result
= value_contents_for_printing (value
);
440 require_not_optimized_out (value
);
445 value_lazy (struct value
*value
)
451 set_value_lazy (struct value
*value
, int val
)
457 value_stack (struct value
*value
)
463 set_value_stack (struct value
*value
, int val
)
469 value_contents (struct value
*value
)
471 const gdb_byte
*result
= value_contents_writeable (value
);
472 require_not_optimized_out (value
);
477 value_contents_writeable (struct value
*value
)
480 value_fetch_lazy (value
);
481 return value_contents_raw (value
);
484 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
485 this function is different from value_equal; in C the operator ==
486 can return 0 even if the two values being compared are equal. */
489 value_contents_equal (struct value
*val1
, struct value
*val2
)
495 type1
= check_typedef (value_type (val1
));
496 type2
= check_typedef (value_type (val2
));
497 len
= TYPE_LENGTH (type1
);
498 if (len
!= TYPE_LENGTH (type2
))
501 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
505 value_optimized_out (struct value
*value
)
507 return value
->optimized_out
;
511 set_value_optimized_out (struct value
*value
, int val
)
513 value
->optimized_out
= val
;
517 value_entirely_optimized_out (const struct value
*value
)
519 if (!value
->optimized_out
)
521 if (value
->lval
!= lval_computed
522 || !value
->location
.computed
.funcs
->check_any_valid
)
524 return !value
->location
.computed
.funcs
->check_any_valid (value
);
528 value_bits_valid (const struct value
*value
, int offset
, int length
)
530 if (value
== NULL
|| !value
->optimized_out
)
532 if (value
->lval
!= lval_computed
533 || !value
->location
.computed
.funcs
->check_validity
)
535 return value
->location
.computed
.funcs
->check_validity (value
, offset
,
540 value_bits_synthetic_pointer (const struct value
*value
,
541 int offset
, int length
)
543 if (value
== NULL
|| value
->lval
!= lval_computed
544 || !value
->location
.computed
.funcs
->check_synthetic_pointer
)
546 return value
->location
.computed
.funcs
->check_synthetic_pointer (value
,
552 value_embedded_offset (struct value
*value
)
554 return value
->embedded_offset
;
558 set_value_embedded_offset (struct value
*value
, int val
)
560 value
->embedded_offset
= val
;
564 value_pointed_to_offset (struct value
*value
)
566 return value
->pointed_to_offset
;
570 set_value_pointed_to_offset (struct value
*value
, int val
)
572 value
->pointed_to_offset
= val
;
576 value_computed_funcs (struct value
*v
)
578 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
580 return v
->location
.computed
.funcs
;
584 value_computed_closure (const struct value
*v
)
586 gdb_assert (v
->lval
== lval_computed
);
588 return v
->location
.computed
.closure
;
592 deprecated_value_lval_hack (struct value
*value
)
598 value_address (struct value
*value
)
600 if (value
->lval
== lval_internalvar
601 || value
->lval
== lval_internalvar_component
)
603 return value
->location
.address
+ value
->offset
;
607 value_raw_address (struct value
*value
)
609 if (value
->lval
== lval_internalvar
610 || value
->lval
== lval_internalvar_component
)
612 return value
->location
.address
;
616 set_value_address (struct value
*value
, CORE_ADDR addr
)
618 gdb_assert (value
->lval
!= lval_internalvar
619 && value
->lval
!= lval_internalvar_component
);
620 value
->location
.address
= addr
;
623 struct internalvar
**
624 deprecated_value_internalvar_hack (struct value
*value
)
626 return &value
->location
.internalvar
;
630 deprecated_value_frame_id_hack (struct value
*value
)
632 return &value
->frame_id
;
636 deprecated_value_regnum_hack (struct value
*value
)
638 return &value
->regnum
;
642 deprecated_value_modifiable (struct value
*value
)
644 return value
->modifiable
;
647 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
649 value
->modifiable
= modifiable
;
652 /* Return a mark in the value chain. All values allocated after the
653 mark is obtained (except for those released) are subject to being freed
654 if a subsequent value_free_to_mark is passed the mark. */
661 /* Take a reference to VAL. VAL will not be deallocated until all
662 references are released. */
665 value_incref (struct value
*val
)
667 val
->reference_count
++;
670 /* Release a reference to VAL, which was acquired with value_incref.
671 This function is also called to deallocate values from the value
675 value_free (struct value
*val
)
679 gdb_assert (val
->reference_count
> 0);
680 val
->reference_count
--;
681 if (val
->reference_count
> 0)
684 /* If there's an associated parent value, drop our reference to
686 if (val
->parent
!= NULL
)
687 value_free (val
->parent
);
689 if (VALUE_LVAL (val
) == lval_computed
)
691 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
693 if (funcs
->free_closure
)
694 funcs
->free_closure (val
);
697 xfree (val
->contents
);
702 /* Free all values allocated since MARK was obtained by value_mark
703 (except for those released). */
705 value_free_to_mark (struct value
*mark
)
710 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
718 /* Free all the values that have been allocated (except for those released).
719 Call after each command, successful or not.
720 In practice this is called before each command, which is sufficient. */
723 free_all_values (void)
728 for (val
= all_values
; val
; val
= next
)
737 /* Frees all the elements in a chain of values. */
740 free_value_chain (struct value
*v
)
746 next
= value_next (v
);
751 /* Remove VAL from the chain all_values
752 so it will not be freed automatically. */
755 release_value (struct value
*val
)
759 if (all_values
== val
)
761 all_values
= val
->next
;
766 for (v
= all_values
; v
; v
= v
->next
)
777 /* Release all values up to mark */
779 value_release_to_mark (struct value
*mark
)
784 for (val
= next
= all_values
; next
; next
= next
->next
)
785 if (next
->next
== mark
)
787 all_values
= next
->next
;
795 /* Return a copy of the value ARG.
796 It contains the same contents, for same memory address,
797 but it's a different block of storage. */
800 value_copy (struct value
*arg
)
802 struct type
*encl_type
= value_enclosing_type (arg
);
805 if (value_lazy (arg
))
806 val
= allocate_value_lazy (encl_type
);
808 val
= allocate_value (encl_type
);
809 val
->type
= arg
->type
;
810 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
811 val
->location
= arg
->location
;
812 val
->offset
= arg
->offset
;
813 val
->bitpos
= arg
->bitpos
;
814 val
->bitsize
= arg
->bitsize
;
815 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
816 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
817 val
->lazy
= arg
->lazy
;
818 val
->optimized_out
= arg
->optimized_out
;
819 val
->embedded_offset
= value_embedded_offset (arg
);
820 val
->pointed_to_offset
= arg
->pointed_to_offset
;
821 val
->modifiable
= arg
->modifiable
;
822 if (!value_lazy (val
))
824 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
825 TYPE_LENGTH (value_enclosing_type (arg
)));
828 val
->parent
= arg
->parent
;
830 value_incref (val
->parent
);
831 if (VALUE_LVAL (val
) == lval_computed
)
833 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
835 if (funcs
->copy_closure
)
836 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
841 /* Return a version of ARG that is non-lvalue. */
844 value_non_lval (struct value
*arg
)
846 if (VALUE_LVAL (arg
) != not_lval
)
848 struct type
*enc_type
= value_enclosing_type (arg
);
849 struct value
*val
= allocate_value (enc_type
);
851 memcpy (value_contents_all_raw (val
), value_contents_all (arg
),
852 TYPE_LENGTH (enc_type
));
853 val
->type
= arg
->type
;
854 set_value_embedded_offset (val
, value_embedded_offset (arg
));
855 set_value_pointed_to_offset (val
, value_pointed_to_offset (arg
));
862 set_value_component_location (struct value
*component
,
863 const struct value
*whole
)
865 if (whole
->lval
== lval_internalvar
)
866 VALUE_LVAL (component
) = lval_internalvar_component
;
868 VALUE_LVAL (component
) = whole
->lval
;
870 component
->location
= whole
->location
;
871 if (whole
->lval
== lval_computed
)
873 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
875 if (funcs
->copy_closure
)
876 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
881 /* Access to the value history. */
883 /* Record a new value in the value history.
884 Returns the absolute history index of the entry.
885 Result of -1 indicates the value was not saved; otherwise it is the
886 value history index of this new item. */
889 record_latest_value (struct value
*val
)
893 /* We don't want this value to have anything to do with the inferior anymore.
894 In particular, "set $1 = 50" should not affect the variable from which
895 the value was taken, and fast watchpoints should be able to assume that
896 a value on the value history never changes. */
897 if (value_lazy (val
))
898 value_fetch_lazy (val
);
899 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
900 from. This is a bit dubious, because then *&$1 does not just return $1
901 but the current contents of that location. c'est la vie... */
905 /* Here we treat value_history_count as origin-zero
906 and applying to the value being stored now. */
908 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
911 struct value_history_chunk
*new
912 = (struct value_history_chunk
*)
914 xmalloc (sizeof (struct value_history_chunk
));
915 memset (new->values
, 0, sizeof new->values
);
916 new->next
= value_history_chain
;
917 value_history_chain
= new;
920 value_history_chain
->values
[i
] = val
;
922 /* Now we regard value_history_count as origin-one
923 and applying to the value just stored. */
925 return ++value_history_count
;
928 /* Return a copy of the value in the history with sequence number NUM. */
931 access_value_history (int num
)
933 struct value_history_chunk
*chunk
;
938 absnum
+= value_history_count
;
943 error (_("The history is empty."));
945 error (_("There is only one value in the history."));
947 error (_("History does not go back to $$%d."), -num
);
949 if (absnum
> value_history_count
)
950 error (_("History has not yet reached $%d."), absnum
);
954 /* Now absnum is always absolute and origin zero. */
956 chunk
= value_history_chain
;
957 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
961 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
965 show_values (char *num_exp
, int from_tty
)
973 /* "show values +" should print from the stored position.
974 "show values <exp>" should print around value number <exp>. */
975 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
976 num
= parse_and_eval_long (num_exp
) - 5;
980 /* "show values" means print the last 10 values. */
981 num
= value_history_count
- 9;
987 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
989 struct value_print_options opts
;
991 val
= access_value_history (i
);
992 printf_filtered (("$%d = "), i
);
993 get_user_print_options (&opts
);
994 value_print (val
, gdb_stdout
, &opts
);
995 printf_filtered (("\n"));
998 /* The next "show values +" should start after what we just printed. */
1001 /* Hitting just return after this command should do the same thing as
1002 "show values +". If num_exp is null, this is unnecessary, since
1003 "show values +" is not useful after "show values". */
1004 if (from_tty
&& num_exp
)
1011 /* Internal variables. These are variables within the debugger
1012 that hold values assigned by debugger commands.
1013 The user refers to them with a '$' prefix
1014 that does not appear in the variable names stored internally. */
1018 struct internalvar
*next
;
1021 /* We support various different kinds of content of an internal variable.
1022 enum internalvar_kind specifies the kind, and union internalvar_data
1023 provides the data associated with this particular kind. */
1025 enum internalvar_kind
1027 /* The internal variable is empty. */
1030 /* The value of the internal variable is provided directly as
1031 a GDB value object. */
1034 /* A fresh value is computed via a call-back routine on every
1035 access to the internal variable. */
1036 INTERNALVAR_MAKE_VALUE
,
1038 /* The internal variable holds a GDB internal convenience function. */
1039 INTERNALVAR_FUNCTION
,
1041 /* The variable holds an integer value. */
1042 INTERNALVAR_INTEGER
,
1044 /* The variable holds a pointer value. */
1045 INTERNALVAR_POINTER
,
1047 /* The variable holds a GDB-provided string. */
1052 union internalvar_data
1054 /* A value object used with INTERNALVAR_VALUE. */
1055 struct value
*value
;
1057 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1058 internalvar_make_value make_value
;
1060 /* The internal function used with INTERNALVAR_FUNCTION. */
1063 struct internal_function
*function
;
1064 /* True if this is the canonical name for the function. */
1068 /* An integer value used with INTERNALVAR_INTEGER. */
1071 /* If type is non-NULL, it will be used as the type to generate
1072 a value for this internal variable. If type is NULL, a default
1073 integer type for the architecture is used. */
1078 /* A pointer value used with INTERNALVAR_POINTER. */
1085 /* A string value used with INTERNALVAR_STRING. */
1090 static struct internalvar
*internalvars
;
1092 /* If the variable does not already exist create it and give it the value given.
1093 If no value is given then the default is zero. */
1095 init_if_undefined_command (char* args
, int from_tty
)
1097 struct internalvar
* intvar
;
1099 /* Parse the expression - this is taken from set_command(). */
1100 struct expression
*expr
= parse_expression (args
);
1101 register struct cleanup
*old_chain
=
1102 make_cleanup (free_current_contents
, &expr
);
1104 /* Validate the expression.
1105 Was the expression an assignment?
1106 Or even an expression at all? */
1107 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1108 error (_("Init-if-undefined requires an assignment expression."));
1110 /* Extract the variable from the parsed expression.
1111 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1112 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1113 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1114 intvar
= expr
->elts
[2].internalvar
;
1116 /* Only evaluate the expression if the lvalue is void.
1117 This may still fail if the expresssion is invalid. */
1118 if (intvar
->kind
== INTERNALVAR_VOID
)
1119 evaluate_expression (expr
);
1121 do_cleanups (old_chain
);
1125 /* Look up an internal variable with name NAME. NAME should not
1126 normally include a dollar sign.
1128 If the specified internal variable does not exist,
1129 the return value is NULL. */
1131 struct internalvar
*
1132 lookup_only_internalvar (const char *name
)
1134 struct internalvar
*var
;
1136 for (var
= internalvars
; var
; var
= var
->next
)
1137 if (strcmp (var
->name
, name
) == 0)
1144 /* Create an internal variable with name NAME and with a void value.
1145 NAME should not normally include a dollar sign. */
1147 struct internalvar
*
1148 create_internalvar (const char *name
)
1150 struct internalvar
*var
;
1152 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1153 var
->name
= concat (name
, (char *)NULL
);
1154 var
->kind
= INTERNALVAR_VOID
;
1155 var
->next
= internalvars
;
1160 /* Create an internal variable with name NAME and register FUN as the
1161 function that value_of_internalvar uses to create a value whenever
1162 this variable is referenced. NAME should not normally include a
1165 struct internalvar
*
1166 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1168 struct internalvar
*var
= create_internalvar (name
);
1170 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1171 var
->u
.make_value
= fun
;
1175 /* Look up an internal variable with name NAME. NAME should not
1176 normally include a dollar sign.
1178 If the specified internal variable does not exist,
1179 one is created, with a void value. */
1181 struct internalvar
*
1182 lookup_internalvar (const char *name
)
1184 struct internalvar
*var
;
1186 var
= lookup_only_internalvar (name
);
1190 return create_internalvar (name
);
1193 /* Return current value of internal variable VAR. For variables that
1194 are not inherently typed, use a value type appropriate for GDBARCH. */
1197 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1203 case INTERNALVAR_VOID
:
1204 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1207 case INTERNALVAR_FUNCTION
:
1208 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1211 case INTERNALVAR_INTEGER
:
1212 if (!var
->u
.integer
.type
)
1213 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1214 var
->u
.integer
.val
);
1216 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1219 case INTERNALVAR_POINTER
:
1220 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1223 case INTERNALVAR_STRING
:
1224 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1225 builtin_type (gdbarch
)->builtin_char
);
1228 case INTERNALVAR_VALUE
:
1229 val
= value_copy (var
->u
.value
);
1230 if (value_lazy (val
))
1231 value_fetch_lazy (val
);
1234 case INTERNALVAR_MAKE_VALUE
:
1235 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1239 internal_error (__FILE__
, __LINE__
, "bad kind");
1242 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1243 on this value go back to affect the original internal variable.
1245 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1246 no underlying modifyable state in the internal variable.
1248 Likewise, if the variable's value is a computed lvalue, we want
1249 references to it to produce another computed lvalue, where
1250 references and assignments actually operate through the
1251 computed value's functions.
1253 This means that internal variables with computed values
1254 behave a little differently from other internal variables:
1255 assignments to them don't just replace the previous value
1256 altogether. At the moment, this seems like the behavior we
1259 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1260 && val
->lval
!= lval_computed
)
1262 VALUE_LVAL (val
) = lval_internalvar
;
1263 VALUE_INTERNALVAR (val
) = var
;
1270 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1274 case INTERNALVAR_INTEGER
:
1275 *result
= var
->u
.integer
.val
;
1284 get_internalvar_function (struct internalvar
*var
,
1285 struct internal_function
**result
)
1289 case INTERNALVAR_FUNCTION
:
1290 *result
= var
->u
.fn
.function
;
1299 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1300 int bitsize
, struct value
*newval
)
1306 case INTERNALVAR_VALUE
:
1307 addr
= value_contents_writeable (var
->u
.value
);
1310 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1311 value_as_long (newval
), bitpos
, bitsize
);
1313 memcpy (addr
+ offset
, value_contents (newval
),
1314 TYPE_LENGTH (value_type (newval
)));
1318 /* We can never get a component of any other kind. */
1319 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1324 set_internalvar (struct internalvar
*var
, struct value
*val
)
1326 enum internalvar_kind new_kind
;
1327 union internalvar_data new_data
= { 0 };
1329 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1330 error (_("Cannot overwrite convenience function %s"), var
->name
);
1332 /* Prepare new contents. */
1333 switch (TYPE_CODE (check_typedef (value_type (val
))))
1335 case TYPE_CODE_VOID
:
1336 new_kind
= INTERNALVAR_VOID
;
1339 case TYPE_CODE_INTERNAL_FUNCTION
:
1340 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1341 new_kind
= INTERNALVAR_FUNCTION
;
1342 get_internalvar_function (VALUE_INTERNALVAR (val
),
1343 &new_data
.fn
.function
);
1344 /* Copies created here are never canonical. */
1348 new_kind
= INTERNALVAR_INTEGER
;
1349 new_data
.integer
.type
= value_type (val
);
1350 new_data
.integer
.val
= value_as_long (val
);
1354 new_kind
= INTERNALVAR_POINTER
;
1355 new_data
.pointer
.type
= value_type (val
);
1356 new_data
.pointer
.val
= value_as_address (val
);
1360 new_kind
= INTERNALVAR_VALUE
;
1361 new_data
.value
= value_copy (val
);
1362 new_data
.value
->modifiable
= 1;
1364 /* Force the value to be fetched from the target now, to avoid problems
1365 later when this internalvar is referenced and the target is gone or
1367 if (value_lazy (new_data
.value
))
1368 value_fetch_lazy (new_data
.value
);
1370 /* Release the value from the value chain to prevent it from being
1371 deleted by free_all_values. From here on this function should not
1372 call error () until new_data is installed into the var->u to avoid
1374 release_value (new_data
.value
);
1378 /* Clean up old contents. */
1379 clear_internalvar (var
);
1382 var
->kind
= new_kind
;
1384 /* End code which must not call error(). */
1388 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1390 /* Clean up old contents. */
1391 clear_internalvar (var
);
1393 var
->kind
= INTERNALVAR_INTEGER
;
1394 var
->u
.integer
.type
= NULL
;
1395 var
->u
.integer
.val
= l
;
1399 set_internalvar_string (struct internalvar
*var
, const char *string
)
1401 /* Clean up old contents. */
1402 clear_internalvar (var
);
1404 var
->kind
= INTERNALVAR_STRING
;
1405 var
->u
.string
= xstrdup (string
);
1409 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1411 /* Clean up old contents. */
1412 clear_internalvar (var
);
1414 var
->kind
= INTERNALVAR_FUNCTION
;
1415 var
->u
.fn
.function
= f
;
1416 var
->u
.fn
.canonical
= 1;
1417 /* Variables installed here are always the canonical version. */
1421 clear_internalvar (struct internalvar
*var
)
1423 /* Clean up old contents. */
1426 case INTERNALVAR_VALUE
:
1427 value_free (var
->u
.value
);
1430 case INTERNALVAR_STRING
:
1431 xfree (var
->u
.string
);
1438 /* Reset to void kind. */
1439 var
->kind
= INTERNALVAR_VOID
;
1443 internalvar_name (struct internalvar
*var
)
1448 static struct internal_function
*
1449 create_internal_function (const char *name
,
1450 internal_function_fn handler
, void *cookie
)
1452 struct internal_function
*ifn
= XNEW (struct internal_function
);
1454 ifn
->name
= xstrdup (name
);
1455 ifn
->handler
= handler
;
1456 ifn
->cookie
= cookie
;
1461 value_internal_function_name (struct value
*val
)
1463 struct internal_function
*ifn
;
1466 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1467 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1468 gdb_assert (result
);
1474 call_internal_function (struct gdbarch
*gdbarch
,
1475 const struct language_defn
*language
,
1476 struct value
*func
, int argc
, struct value
**argv
)
1478 struct internal_function
*ifn
;
1481 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1482 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1483 gdb_assert (result
);
1485 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1488 /* The 'function' command. This does nothing -- it is just a
1489 placeholder to let "help function NAME" work. This is also used as
1490 the implementation of the sub-command that is created when
1491 registering an internal function. */
1493 function_command (char *command
, int from_tty
)
1498 /* Clean up if an internal function's command is destroyed. */
1500 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1506 /* Add a new internal function. NAME is the name of the function; DOC
1507 is a documentation string describing the function. HANDLER is
1508 called when the function is invoked. COOKIE is an arbitrary
1509 pointer which is passed to HANDLER and is intended for "user
1512 add_internal_function (const char *name
, const char *doc
,
1513 internal_function_fn handler
, void *cookie
)
1515 struct cmd_list_element
*cmd
;
1516 struct internal_function
*ifn
;
1517 struct internalvar
*var
= lookup_internalvar (name
);
1519 ifn
= create_internal_function (name
, handler
, cookie
);
1520 set_internalvar_function (var
, ifn
);
1522 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1524 cmd
->destroyer
= function_destroyer
;
1527 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1528 prevent cycles / duplicates. */
1531 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1532 htab_t copied_types
)
1534 if (TYPE_OBJFILE (value
->type
) == objfile
)
1535 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1537 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1538 value
->enclosing_type
= copy_type_recursive (objfile
,
1539 value
->enclosing_type
,
1543 /* Likewise for internal variable VAR. */
1546 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1547 htab_t copied_types
)
1551 case INTERNALVAR_INTEGER
:
1552 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1554 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1557 case INTERNALVAR_POINTER
:
1558 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1560 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1563 case INTERNALVAR_VALUE
:
1564 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1569 /* Update the internal variables and value history when OBJFILE is
1570 discarded; we must copy the types out of the objfile. New global types
1571 will be created for every convenience variable which currently points to
1572 this objfile's types, and the convenience variables will be adjusted to
1573 use the new global types. */
1576 preserve_values (struct objfile
*objfile
)
1578 htab_t copied_types
;
1579 struct value_history_chunk
*cur
;
1580 struct internalvar
*var
;
1583 /* Create the hash table. We allocate on the objfile's obstack, since
1584 it is soon to be deleted. */
1585 copied_types
= create_copied_types_hash (objfile
);
1587 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1588 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1590 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1592 for (var
= internalvars
; var
; var
= var
->next
)
1593 preserve_one_internalvar (var
, objfile
, copied_types
);
1595 preserve_python_values (objfile
, copied_types
);
1597 htab_delete (copied_types
);
1601 show_convenience (char *ignore
, int from_tty
)
1603 struct gdbarch
*gdbarch
= get_current_arch ();
1604 struct internalvar
*var
;
1606 struct value_print_options opts
;
1608 get_user_print_options (&opts
);
1609 for (var
= internalvars
; var
; var
= var
->next
)
1615 printf_filtered (("$%s = "), var
->name
);
1616 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1618 printf_filtered (("\n"));
1621 printf_unfiltered (_("\
1622 No debugger convenience variables now defined.\n\
1623 Convenience variables have names starting with \"$\";\n\
1624 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1627 /* Extract a value as a C number (either long or double).
1628 Knows how to convert fixed values to double, or
1629 floating values to long.
1630 Does not deallocate the value. */
1633 value_as_long (struct value
*val
)
1635 /* This coerces arrays and functions, which is necessary (e.g.
1636 in disassemble_command). It also dereferences references, which
1637 I suspect is the most logical thing to do. */
1638 val
= coerce_array (val
);
1639 return unpack_long (value_type (val
), value_contents (val
));
1643 value_as_double (struct value
*val
)
1648 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1650 error (_("Invalid floating value found in program."));
1654 /* Extract a value as a C pointer. Does not deallocate the value.
1655 Note that val's type may not actually be a pointer; value_as_long
1656 handles all the cases. */
1658 value_as_address (struct value
*val
)
1660 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1662 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1663 whether we want this to be true eventually. */
1665 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1666 non-address (e.g. argument to "signal", "info break", etc.), or
1667 for pointers to char, in which the low bits *are* significant. */
1668 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1671 /* There are several targets (IA-64, PowerPC, and others) which
1672 don't represent pointers to functions as simply the address of
1673 the function's entry point. For example, on the IA-64, a
1674 function pointer points to a two-word descriptor, generated by
1675 the linker, which contains the function's entry point, and the
1676 value the IA-64 "global pointer" register should have --- to
1677 support position-independent code. The linker generates
1678 descriptors only for those functions whose addresses are taken.
1680 On such targets, it's difficult for GDB to convert an arbitrary
1681 function address into a function pointer; it has to either find
1682 an existing descriptor for that function, or call malloc and
1683 build its own. On some targets, it is impossible for GDB to
1684 build a descriptor at all: the descriptor must contain a jump
1685 instruction; data memory cannot be executed; and code memory
1688 Upon entry to this function, if VAL is a value of type `function'
1689 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1690 value_address (val) is the address of the function. This is what
1691 you'll get if you evaluate an expression like `main'. The call
1692 to COERCE_ARRAY below actually does all the usual unary
1693 conversions, which includes converting values of type `function'
1694 to `pointer to function'. This is the challenging conversion
1695 discussed above. Then, `unpack_long' will convert that pointer
1696 back into an address.
1698 So, suppose the user types `disassemble foo' on an architecture
1699 with a strange function pointer representation, on which GDB
1700 cannot build its own descriptors, and suppose further that `foo'
1701 has no linker-built descriptor. The address->pointer conversion
1702 will signal an error and prevent the command from running, even
1703 though the next step would have been to convert the pointer
1704 directly back into the same address.
1706 The following shortcut avoids this whole mess. If VAL is a
1707 function, just return its address directly. */
1708 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1709 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1710 return value_address (val
);
1712 val
= coerce_array (val
);
1714 /* Some architectures (e.g. Harvard), map instruction and data
1715 addresses onto a single large unified address space. For
1716 instance: An architecture may consider a large integer in the
1717 range 0x10000000 .. 0x1000ffff to already represent a data
1718 addresses (hence not need a pointer to address conversion) while
1719 a small integer would still need to be converted integer to
1720 pointer to address. Just assume such architectures handle all
1721 integer conversions in a single function. */
1725 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1726 must admonish GDB hackers to make sure its behavior matches the
1727 compiler's, whenever possible.
1729 In general, I think GDB should evaluate expressions the same way
1730 the compiler does. When the user copies an expression out of
1731 their source code and hands it to a `print' command, they should
1732 get the same value the compiler would have computed. Any
1733 deviation from this rule can cause major confusion and annoyance,
1734 and needs to be justified carefully. In other words, GDB doesn't
1735 really have the freedom to do these conversions in clever and
1738 AndrewC pointed out that users aren't complaining about how GDB
1739 casts integers to pointers; they are complaining that they can't
1740 take an address from a disassembly listing and give it to `x/i'.
1741 This is certainly important.
1743 Adding an architecture method like integer_to_address() certainly
1744 makes it possible for GDB to "get it right" in all circumstances
1745 --- the target has complete control over how things get done, so
1746 people can Do The Right Thing for their target without breaking
1747 anyone else. The standard doesn't specify how integers get
1748 converted to pointers; usually, the ABI doesn't either, but
1749 ABI-specific code is a more reasonable place to handle it. */
1751 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1752 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1753 && gdbarch_integer_to_address_p (gdbarch
))
1754 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1755 value_contents (val
));
1757 return unpack_long (value_type (val
), value_contents (val
));
1761 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1762 as a long, or as a double, assuming the raw data is described
1763 by type TYPE. Knows how to convert different sizes of values
1764 and can convert between fixed and floating point. We don't assume
1765 any alignment for the raw data. Return value is in host byte order.
1767 If you want functions and arrays to be coerced to pointers, and
1768 references to be dereferenced, call value_as_long() instead.
1770 C++: It is assumed that the front-end has taken care of
1771 all matters concerning pointers to members. A pointer
1772 to member which reaches here is considered to be equivalent
1773 to an INT (or some size). After all, it is only an offset. */
1776 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1778 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1779 enum type_code code
= TYPE_CODE (type
);
1780 int len
= TYPE_LENGTH (type
);
1781 int nosign
= TYPE_UNSIGNED (type
);
1785 case TYPE_CODE_TYPEDEF
:
1786 return unpack_long (check_typedef (type
), valaddr
);
1787 case TYPE_CODE_ENUM
:
1788 case TYPE_CODE_FLAGS
:
1789 case TYPE_CODE_BOOL
:
1791 case TYPE_CODE_CHAR
:
1792 case TYPE_CODE_RANGE
:
1793 case TYPE_CODE_MEMBERPTR
:
1795 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1797 return extract_signed_integer (valaddr
, len
, byte_order
);
1800 return extract_typed_floating (valaddr
, type
);
1802 case TYPE_CODE_DECFLOAT
:
1803 /* libdecnumber has a function to convert from decimal to integer, but
1804 it doesn't work when the decimal number has a fractional part. */
1805 return decimal_to_doublest (valaddr
, len
, byte_order
);
1809 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1810 whether we want this to be true eventually. */
1811 return extract_typed_address (valaddr
, type
);
1814 error (_("Value can't be converted to integer."));
1816 return 0; /* Placate lint. */
1819 /* Return a double value from the specified type and address.
1820 INVP points to an int which is set to 0 for valid value,
1821 1 for invalid value (bad float format). In either case,
1822 the returned double is OK to use. Argument is in target
1823 format, result is in host format. */
1826 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1828 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1829 enum type_code code
;
1833 *invp
= 0; /* Assume valid. */
1834 CHECK_TYPEDEF (type
);
1835 code
= TYPE_CODE (type
);
1836 len
= TYPE_LENGTH (type
);
1837 nosign
= TYPE_UNSIGNED (type
);
1838 if (code
== TYPE_CODE_FLT
)
1840 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1841 floating-point value was valid (using the macro
1842 INVALID_FLOAT). That test/macro have been removed.
1844 It turns out that only the VAX defined this macro and then
1845 only in a non-portable way. Fixing the portability problem
1846 wouldn't help since the VAX floating-point code is also badly
1847 bit-rotten. The target needs to add definitions for the
1848 methods gdbarch_float_format and gdbarch_double_format - these
1849 exactly describe the target floating-point format. The
1850 problem here is that the corresponding floatformat_vax_f and
1851 floatformat_vax_d values these methods should be set to are
1852 also not defined either. Oops!
1854 Hopefully someone will add both the missing floatformat
1855 definitions and the new cases for floatformat_is_valid (). */
1857 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1863 return extract_typed_floating (valaddr
, type
);
1865 else if (code
== TYPE_CODE_DECFLOAT
)
1866 return decimal_to_doublest (valaddr
, len
, byte_order
);
1869 /* Unsigned -- be sure we compensate for signed LONGEST. */
1870 return (ULONGEST
) unpack_long (type
, valaddr
);
1874 /* Signed -- we are OK with unpack_long. */
1875 return unpack_long (type
, valaddr
);
1879 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1880 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1881 We don't assume any alignment for the raw data. Return value is in
1884 If you want functions and arrays to be coerced to pointers, and
1885 references to be dereferenced, call value_as_address() instead.
1887 C++: It is assumed that the front-end has taken care of
1888 all matters concerning pointers to members. A pointer
1889 to member which reaches here is considered to be equivalent
1890 to an INT (or some size). After all, it is only an offset. */
1893 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1895 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1896 whether we want this to be true eventually. */
1897 return unpack_long (type
, valaddr
);
1901 /* Get the value of the FIELDNO'th field (which must be static) of
1902 TYPE. Return NULL if the field doesn't exist or has been
1906 value_static_field (struct type
*type
, int fieldno
)
1908 struct value
*retval
;
1910 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
1912 case FIELD_LOC_KIND_PHYSADDR
:
1913 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1914 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1916 case FIELD_LOC_KIND_PHYSNAME
:
1918 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1919 /*TYPE_FIELD_NAME (type, fieldno);*/
1920 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1924 /* With some compilers, e.g. HP aCC, static data members are
1925 reported as non-debuggable symbols */
1926 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1933 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1934 SYMBOL_VALUE_ADDRESS (msym
));
1938 retval
= value_of_variable (sym
, NULL
);
1942 gdb_assert_not_reached ("unexpected field location kind");
1948 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1949 You have to be careful here, since the size of the data area for the value
1950 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1951 than the old enclosing type, you have to allocate more space for the
1955 set_value_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1957 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1959 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1961 val
->enclosing_type
= new_encl_type
;
1964 /* Given a value ARG1 (offset by OFFSET bytes)
1965 of a struct or union type ARG_TYPE,
1966 extract and return the value of one of its (non-static) fields.
1967 FIELDNO says which field. */
1970 value_primitive_field (struct value
*arg1
, int offset
,
1971 int fieldno
, struct type
*arg_type
)
1976 CHECK_TYPEDEF (arg_type
);
1977 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1979 /* Call check_typedef on our type to make sure that, if TYPE
1980 is a TYPE_CODE_TYPEDEF, its length is set to the length
1981 of the target type instead of zero. However, we do not
1982 replace the typedef type by the target type, because we want
1983 to keep the typedef in order to be able to print the type
1984 description correctly. */
1985 check_typedef (type
);
1987 /* Handle packed fields */
1989 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
1991 /* Create a new value for the bitfield, with bitpos and bitsize
1992 set. If possible, arrange offset and bitpos so that we can
1993 do a single aligned read of the size of the containing type.
1994 Otherwise, adjust offset to the byte containing the first
1995 bit. Assume that the address, offset, and embedded offset
1996 are sufficiently aligned. */
1997 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
1998 int container_bitsize
= TYPE_LENGTH (type
) * 8;
2000 v
= allocate_value_lazy (type
);
2001 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
2002 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
2003 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
2004 v
->bitpos
= bitpos
% container_bitsize
;
2006 v
->bitpos
= bitpos
% 8;
2007 v
->offset
= (value_embedded_offset (arg1
)
2009 + (bitpos
- v
->bitpos
) / 8);
2011 value_incref (v
->parent
);
2012 if (!value_lazy (arg1
))
2013 value_fetch_lazy (v
);
2015 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
2017 /* This field is actually a base subobject, so preserve the
2018 entire object's contents for later references to virtual
2021 /* Lazy register values with offsets are not supported. */
2022 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2023 value_fetch_lazy (arg1
);
2025 if (value_lazy (arg1
))
2026 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2029 v
= allocate_value (value_enclosing_type (arg1
));
2030 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2031 TYPE_LENGTH (value_enclosing_type (arg1
)));
2034 v
->offset
= value_offset (arg1
);
2035 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2036 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2040 /* Plain old data member */
2041 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2043 /* Lazy register values with offsets are not supported. */
2044 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2045 value_fetch_lazy (arg1
);
2047 if (value_lazy (arg1
))
2048 v
= allocate_value_lazy (type
);
2051 v
= allocate_value (type
);
2052 memcpy (value_contents_raw (v
),
2053 value_contents_raw (arg1
) + offset
,
2054 TYPE_LENGTH (type
));
2056 v
->offset
= (value_offset (arg1
) + offset
2057 + value_embedded_offset (arg1
));
2059 set_value_component_location (v
, arg1
);
2060 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2061 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2065 /* Given a value ARG1 of a struct or union type,
2066 extract and return the value of one of its (non-static) fields.
2067 FIELDNO says which field. */
2070 value_field (struct value
*arg1
, int fieldno
)
2072 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2075 /* Return a non-virtual function as a value.
2076 F is the list of member functions which contains the desired method.
2077 J is an index into F which provides the desired method.
2079 We only use the symbol for its address, so be happy with either a
2080 full symbol or a minimal symbol.
2084 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
2088 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2089 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2091 struct minimal_symbol
*msym
;
2093 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2100 gdb_assert (sym
== NULL
);
2101 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2106 v
= allocate_value (ftype
);
2109 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2113 /* The minimal symbol might point to a function descriptor;
2114 resolve it to the actual code address instead. */
2115 struct objfile
*objfile
= msymbol_objfile (msym
);
2116 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2118 set_value_address (v
,
2119 gdbarch_convert_from_func_ptr_addr
2120 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2125 if (type
!= value_type (*arg1p
))
2126 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2127 value_addr (*arg1p
)));
2129 /* Move the `this' pointer according to the offset.
2130 VALUE_OFFSET (*arg1p) += offset;
2138 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2139 object at VALADDR. The bitfield starts at BITPOS bits and contains
2142 Extracting bits depends on endianness of the machine. Compute the
2143 number of least significant bits to discard. For big endian machines,
2144 we compute the total number of bits in the anonymous object, subtract
2145 off the bit count from the MSB of the object to the MSB of the
2146 bitfield, then the size of the bitfield, which leaves the LSB discard
2147 count. For little endian machines, the discard count is simply the
2148 number of bits from the LSB of the anonymous object to the LSB of the
2151 If the field is signed, we also do sign extension. */
2154 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2155 int bitpos
, int bitsize
)
2157 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2163 /* Read the minimum number of bytes required; there may not be
2164 enough bytes to read an entire ULONGEST. */
2165 CHECK_TYPEDEF (field_type
);
2167 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2169 bytes_read
= TYPE_LENGTH (field_type
);
2171 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2172 bytes_read
, byte_order
);
2174 /* Extract bits. See comment above. */
2176 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2177 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2179 lsbcount
= (bitpos
% 8);
2182 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2183 If the field is signed, and is negative, then sign extend. */
2185 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2187 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2189 if (!TYPE_UNSIGNED (field_type
))
2191 if (val
& (valmask
^ (valmask
>> 1)))
2200 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2201 VALADDR. See unpack_bits_as_long for more details. */
2204 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2206 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2207 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2208 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2210 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2213 /* Modify the value of a bitfield. ADDR points to a block of memory in
2214 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2215 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2216 indicate which bits (in target bit order) comprise the bitfield.
2217 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
2218 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2221 modify_field (struct type
*type
, gdb_byte
*addr
,
2222 LONGEST fieldval
, int bitpos
, int bitsize
)
2224 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2226 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2229 /* Normalize BITPOS. */
2233 /* If a negative fieldval fits in the field in question, chop
2234 off the sign extension bits. */
2235 if ((~fieldval
& ~(mask
>> 1)) == 0)
2238 /* Warn if value is too big to fit in the field in question. */
2239 if (0 != (fieldval
& ~mask
))
2241 /* FIXME: would like to include fieldval in the message, but
2242 we don't have a sprintf_longest. */
2243 warning (_("Value does not fit in %d bits."), bitsize
);
2245 /* Truncate it, otherwise adjoining fields may be corrupted. */
2249 /* Ensure no bytes outside of the modified ones get accessed as it may cause
2250 false valgrind reports. */
2252 bytesize
= (bitpos
+ bitsize
+ 7) / 8;
2253 oword
= extract_unsigned_integer (addr
, bytesize
, byte_order
);
2255 /* Shifting for bit field depends on endianness of the target machine. */
2256 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2257 bitpos
= bytesize
* 8 - bitpos
- bitsize
;
2259 oword
&= ~(mask
<< bitpos
);
2260 oword
|= fieldval
<< bitpos
;
2262 store_unsigned_integer (addr
, bytesize
, byte_order
, oword
);
2265 /* Pack NUM into BUF using a target format of TYPE. */
2268 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2270 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2273 type
= check_typedef (type
);
2274 len
= TYPE_LENGTH (type
);
2276 switch (TYPE_CODE (type
))
2279 case TYPE_CODE_CHAR
:
2280 case TYPE_CODE_ENUM
:
2281 case TYPE_CODE_FLAGS
:
2282 case TYPE_CODE_BOOL
:
2283 case TYPE_CODE_RANGE
:
2284 case TYPE_CODE_MEMBERPTR
:
2285 store_signed_integer (buf
, len
, byte_order
, num
);
2290 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2294 error (_("Unexpected type (%d) encountered for integer constant."),
2300 /* Pack NUM into BUF using a target format of TYPE. */
2303 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2306 enum bfd_endian byte_order
;
2308 type
= check_typedef (type
);
2309 len
= TYPE_LENGTH (type
);
2310 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2312 switch (TYPE_CODE (type
))
2315 case TYPE_CODE_CHAR
:
2316 case TYPE_CODE_ENUM
:
2317 case TYPE_CODE_FLAGS
:
2318 case TYPE_CODE_BOOL
:
2319 case TYPE_CODE_RANGE
:
2320 case TYPE_CODE_MEMBERPTR
:
2321 store_unsigned_integer (buf
, len
, byte_order
, num
);
2326 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2331 Unexpected type (%d) encountered for unsigned integer constant."),
2337 /* Convert C numbers into newly allocated values. */
2340 value_from_longest (struct type
*type
, LONGEST num
)
2342 struct value
*val
= allocate_value (type
);
2344 pack_long (value_contents_raw (val
), type
, num
);
2349 /* Convert C unsigned numbers into newly allocated values. */
2352 value_from_ulongest (struct type
*type
, ULONGEST num
)
2354 struct value
*val
= allocate_value (type
);
2356 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2362 /* Create a value representing a pointer of type TYPE to the address
2365 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2367 struct value
*val
= allocate_value (type
);
2369 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2374 /* Create a value of type TYPE whose contents come from VALADDR, if it
2375 is non-null, and whose memory address (in the inferior) is
2379 value_from_contents_and_address (struct type
*type
,
2380 const gdb_byte
*valaddr
,
2383 struct value
*v
= allocate_value (type
);
2385 if (valaddr
== NULL
)
2386 set_value_lazy (v
, 1);
2388 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2389 set_value_address (v
, address
);
2390 VALUE_LVAL (v
) = lval_memory
;
2395 value_from_double (struct type
*type
, DOUBLEST num
)
2397 struct value
*val
= allocate_value (type
);
2398 struct type
*base_type
= check_typedef (type
);
2399 enum type_code code
= TYPE_CODE (base_type
);
2401 if (code
== TYPE_CODE_FLT
)
2403 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2406 error (_("Unexpected type encountered for floating constant."));
2412 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2414 struct value
*val
= allocate_value (type
);
2416 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2421 coerce_ref (struct value
*arg
)
2423 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2425 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2426 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2427 unpack_pointer (value_type (arg
),
2428 value_contents (arg
)));
2433 coerce_array (struct value
*arg
)
2437 arg
= coerce_ref (arg
);
2438 type
= check_typedef (value_type (arg
));
2440 switch (TYPE_CODE (type
))
2442 case TYPE_CODE_ARRAY
:
2443 if (!TYPE_VECTOR (type
) && current_language
->c_style_arrays
)
2444 arg
= value_coerce_array (arg
);
2446 case TYPE_CODE_FUNC
:
2447 arg
= value_coerce_function (arg
);
2454 /* Return true if the function returning the specified type is using
2455 the convention of returning structures in memory (passing in the
2456 address as a hidden first parameter). */
2459 using_struct_return (struct gdbarch
*gdbarch
,
2460 struct type
*func_type
, struct type
*value_type
)
2462 enum type_code code
= TYPE_CODE (value_type
);
2464 if (code
== TYPE_CODE_ERROR
)
2465 error (_("Function return type unknown."));
2467 if (code
== TYPE_CODE_VOID
)
2468 /* A void return value is never in memory. See also corresponding
2469 code in "print_return_value". */
2472 /* Probe the architecture for the return-value convention. */
2473 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2475 != RETURN_VALUE_REGISTER_CONVENTION
);
2478 /* Set the initialized field in a value struct. */
2481 set_value_initialized (struct value
*val
, int status
)
2483 val
->initialized
= status
;
2486 /* Return the initialized field in a value struct. */
2489 value_initialized (struct value
*val
)
2491 return val
->initialized
;
2495 _initialize_values (void)
2497 add_cmd ("convenience", no_class
, show_convenience
, _("\
2498 Debugger convenience (\"$foo\") variables.\n\
2499 These variables are created when you assign them values;\n\
2500 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2502 A few convenience variables are given values automatically:\n\
2503 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2504 \"$__\" holds the contents of the last address examined with \"x\"."),
2507 add_cmd ("values", no_class
, show_values
,
2508 _("Elements of value history around item number IDX (or last ten)."),
2511 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2512 Initialize a convenience variable if necessary.\n\
2513 init-if-undefined VARIABLE = EXPRESSION\n\
2514 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2515 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2516 VARIABLE is already initialized."));
2518 add_prefix_cmd ("function", no_class
, function_command
, _("\
2519 Placeholder command for showing help on convenience functions."),
2520 &functionlist
, "function ", 0, &cmdlist
);