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, 2011 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 #include "tracepoint.h"
47 /* Prototypes for exported functions. */
49 void _initialize_values (void);
51 /* Definition of a user function. */
52 struct internal_function
54 /* The name of the function. It is a bit odd to have this in the
55 function itself -- the user might use a differently-named
56 convenience variable to hold the function. */
60 internal_function_fn handler
;
62 /* User data for the handler. */
66 static struct cmd_list_element
*functionlist
;
70 /* Type of value; either not an lval, or one of the various
71 different possible kinds of lval. */
74 /* Is it modifiable? Only relevant if lval != not_lval. */
77 /* Location of value (if lval). */
80 /* If lval == lval_memory, this is the address in the inferior.
81 If lval == lval_register, this is the byte offset into the
82 registers structure. */
85 /* Pointer to internal variable. */
86 struct internalvar
*internalvar
;
88 /* If lval == lval_computed, this is a set of function pointers
89 to use to access and describe the value, and a closure pointer
93 struct lval_funcs
*funcs
; /* Functions to call. */
94 void *closure
; /* Closure for those functions to use. */
98 /* Describes offset of a value within lval of a structure in bytes.
99 If lval == lval_memory, this is an offset to the address. If
100 lval == lval_register, this is a further offset from
101 location.address within the registers structure. Note also the
102 member embedded_offset below. */
105 /* Only used for bitfields; number of bits contained in them. */
108 /* Only used for bitfields; position of start of field. For
109 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
110 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
113 /* Only used for bitfields; the containing value. This allows a
114 single read from the target when displaying multiple
116 struct value
*parent
;
118 /* Frame register value is relative to. This will be described in
119 the lval enum above as "lval_register". */
120 struct frame_id frame_id
;
122 /* Type of the value. */
125 /* If a value represents a C++ object, then the `type' field gives
126 the object's compile-time type. If the object actually belongs
127 to some class derived from `type', perhaps with other base
128 classes and additional members, then `type' is just a subobject
129 of the real thing, and the full object is probably larger than
130 `type' would suggest.
132 If `type' is a dynamic class (i.e. one with a vtable), then GDB
133 can actually determine the object's run-time type by looking at
134 the run-time type information in the vtable. When this
135 information is available, we may elect to read in the entire
136 object, for several reasons:
138 - When printing the value, the user would probably rather see the
139 full object, not just the limited portion apparent from the
142 - If `type' has virtual base classes, then even printing `type'
143 alone may require reaching outside the `type' portion of the
144 object to wherever the virtual base class has been stored.
146 When we store the entire object, `enclosing_type' is the run-time
147 type -- the complete object -- and `embedded_offset' is the
148 offset of `type' within that larger type, in bytes. The
149 value_contents() macro takes `embedded_offset' into account, so
150 most GDB code continues to see the `type' portion of the value,
151 just as the inferior would.
153 If `type' is a pointer to an object, then `enclosing_type' is a
154 pointer to the object's run-time type, and `pointed_to_offset' is
155 the offset in bytes from the full object to the pointed-to object
156 -- that is, the value `embedded_offset' would have if we followed
157 the pointer and fetched the complete object. (I don't really see
158 the point. Why not just determine the run-time type when you
159 indirect, and avoid the special case? The contents don't matter
160 until you indirect anyway.)
162 If we're not doing anything fancy, `enclosing_type' is equal to
163 `type', and `embedded_offset' is zero, so everything works
165 struct type
*enclosing_type
;
167 int pointed_to_offset
;
169 /* Values are stored in a chain, so that they can be deleted easily
170 over calls to the inferior. Values assigned to internal
171 variables, put into the value history or exposed to Python are
172 taken off this list. */
175 /* Register number if the value is from a register. */
178 /* If zero, contents of this value are in the contents field. If
179 nonzero, contents are in inferior. If the lval field is lval_memory,
180 the contents are in inferior memory at location.address plus offset.
181 The lval field may also be lval_register.
183 WARNING: This field is used by the code which handles watchpoints
184 (see breakpoint.c) to decide whether a particular value can be
185 watched by hardware watchpoints. If the lazy flag is set for
186 some member of a value chain, it is assumed that this member of
187 the chain doesn't need to be watched as part of watching the
188 value itself. This is how GDB avoids watching the entire struct
189 or array when the user wants to watch a single struct member or
190 array element. If you ever change the way lazy flag is set and
191 reset, be sure to consider this use as well! */
194 /* If nonzero, this is the value of a variable which does not
195 actually exist in the program. */
198 /* If value is a variable, is it initialized or not. */
201 /* If value is from the stack. If this is set, read_stack will be
202 used instead of read_memory to enable extra caching. */
205 /* Actual contents of the value. Target byte-order. NULL or not
206 valid if lazy is nonzero. */
209 /* The number of references to this value. When a value is created,
210 the value chain holds a reference, so REFERENCE_COUNT is 1. If
211 release_value is called, this value is removed from the chain but
212 the caller of release_value now has a reference to this value.
213 The caller must arrange for a call to value_free later. */
217 /* Prototypes for local functions. */
219 static void show_values (char *, int);
221 static void show_convenience (char *, int);
224 /* The value-history records all the values printed
225 by print commands during this session. Each chunk
226 records 60 consecutive values. The first chunk on
227 the chain records the most recent values.
228 The total number of values is in value_history_count. */
230 #define VALUE_HISTORY_CHUNK 60
232 struct value_history_chunk
234 struct value_history_chunk
*next
;
235 struct value
*values
[VALUE_HISTORY_CHUNK
];
238 /* Chain of chunks now in use. */
240 static struct value_history_chunk
*value_history_chain
;
242 static int value_history_count
; /* Abs number of last entry stored */
245 /* List of all value objects currently allocated
246 (except for those released by calls to release_value)
247 This is so they can be freed after each command. */
249 static struct value
*all_values
;
251 /* Allocate a lazy value for type TYPE. Its actual content is
252 "lazily" allocated too: the content field of the return value is
253 NULL; it will be allocated when it is fetched from the target. */
256 allocate_value_lazy (struct type
*type
)
260 /* Call check_typedef on our type to make sure that, if TYPE
261 is a TYPE_CODE_TYPEDEF, its length is set to the length
262 of the target type instead of zero. However, we do not
263 replace the typedef type by the target type, because we want
264 to keep the typedef in order to be able to set the VAL's type
265 description correctly. */
266 check_typedef (type
);
268 val
= (struct value
*) xzalloc (sizeof (struct value
));
269 val
->contents
= NULL
;
270 val
->next
= all_values
;
273 val
->enclosing_type
= type
;
274 VALUE_LVAL (val
) = not_lval
;
275 val
->location
.address
= 0;
276 VALUE_FRAME_ID (val
) = null_frame_id
;
280 VALUE_REGNUM (val
) = -1;
282 val
->optimized_out
= 0;
283 val
->embedded_offset
= 0;
284 val
->pointed_to_offset
= 0;
286 val
->initialized
= 1; /* Default to initialized. */
288 /* Values start out on the all_values chain. */
289 val
->reference_count
= 1;
294 /* Allocate the contents of VAL if it has not been allocated yet. */
297 allocate_value_contents (struct value
*val
)
300 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
303 /* Allocate a value and its contents for type TYPE. */
306 allocate_value (struct type
*type
)
308 struct value
*val
= allocate_value_lazy (type
);
310 allocate_value_contents (val
);
315 /* Allocate a value that has the correct length
316 for COUNT repetitions of type TYPE. */
319 allocate_repeat_value (struct type
*type
, int count
)
321 int low_bound
= current_language
->string_lower_bound
; /* ??? */
322 /* FIXME-type-allocation: need a way to free this type when we are
324 struct type
*array_type
325 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
327 return allocate_value (array_type
);
331 allocate_computed_value (struct type
*type
,
332 struct lval_funcs
*funcs
,
335 struct value
*v
= allocate_value (type
);
337 VALUE_LVAL (v
) = lval_computed
;
338 v
->location
.computed
.funcs
= funcs
;
339 v
->location
.computed
.closure
= closure
;
340 set_value_lazy (v
, 1);
345 /* Accessor methods. */
348 value_next (struct value
*value
)
354 value_type (const struct value
*value
)
359 deprecated_set_value_type (struct value
*value
, struct type
*type
)
365 value_offset (const struct value
*value
)
367 return value
->offset
;
370 set_value_offset (struct value
*value
, int offset
)
372 value
->offset
= offset
;
376 value_bitpos (const struct value
*value
)
378 return value
->bitpos
;
381 set_value_bitpos (struct value
*value
, int bit
)
387 value_bitsize (const struct value
*value
)
389 return value
->bitsize
;
392 set_value_bitsize (struct value
*value
, int bit
)
394 value
->bitsize
= bit
;
398 value_parent (struct value
*value
)
400 return value
->parent
;
404 value_contents_raw (struct value
*value
)
406 allocate_value_contents (value
);
407 return value
->contents
+ value
->embedded_offset
;
411 value_contents_all_raw (struct value
*value
)
413 allocate_value_contents (value
);
414 return value
->contents
;
418 value_enclosing_type (struct value
*value
)
420 return value
->enclosing_type
;
424 require_not_optimized_out (struct value
*value
)
426 if (value
->optimized_out
)
427 error (_("value has been optimized out"));
431 value_contents_for_printing (struct value
*value
)
434 value_fetch_lazy (value
);
435 return value
->contents
;
439 value_contents_all (struct value
*value
)
441 const gdb_byte
*result
= value_contents_for_printing (value
);
442 require_not_optimized_out (value
);
447 value_lazy (struct value
*value
)
453 set_value_lazy (struct value
*value
, int val
)
459 value_stack (struct value
*value
)
465 set_value_stack (struct value
*value
, int val
)
471 value_contents (struct value
*value
)
473 const gdb_byte
*result
= value_contents_writeable (value
);
474 require_not_optimized_out (value
);
479 value_contents_writeable (struct value
*value
)
482 value_fetch_lazy (value
);
483 return value_contents_raw (value
);
486 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
487 this function is different from value_equal; in C the operator ==
488 can return 0 even if the two values being compared are equal. */
491 value_contents_equal (struct value
*val1
, struct value
*val2
)
497 type1
= check_typedef (value_type (val1
));
498 type2
= check_typedef (value_type (val2
));
499 len
= TYPE_LENGTH (type1
);
500 if (len
!= TYPE_LENGTH (type2
))
503 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
507 value_optimized_out (struct value
*value
)
509 return value
->optimized_out
;
513 set_value_optimized_out (struct value
*value
, int val
)
515 value
->optimized_out
= val
;
519 value_entirely_optimized_out (const struct value
*value
)
521 if (!value
->optimized_out
)
523 if (value
->lval
!= lval_computed
524 || !value
->location
.computed
.funcs
->check_any_valid
)
526 return !value
->location
.computed
.funcs
->check_any_valid (value
);
530 value_bits_valid (const struct value
*value
, int offset
, int length
)
532 if (value
== NULL
|| !value
->optimized_out
)
534 if (value
->lval
!= lval_computed
535 || !value
->location
.computed
.funcs
->check_validity
)
537 return value
->location
.computed
.funcs
->check_validity (value
, offset
,
542 value_bits_synthetic_pointer (const struct value
*value
,
543 int offset
, int length
)
545 if (value
== NULL
|| value
->lval
!= lval_computed
546 || !value
->location
.computed
.funcs
->check_synthetic_pointer
)
548 return value
->location
.computed
.funcs
->check_synthetic_pointer (value
,
554 value_embedded_offset (struct value
*value
)
556 return value
->embedded_offset
;
560 set_value_embedded_offset (struct value
*value
, int val
)
562 value
->embedded_offset
= val
;
566 value_pointed_to_offset (struct value
*value
)
568 return value
->pointed_to_offset
;
572 set_value_pointed_to_offset (struct value
*value
, int val
)
574 value
->pointed_to_offset
= val
;
578 value_computed_funcs (struct value
*v
)
580 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
582 return v
->location
.computed
.funcs
;
586 value_computed_closure (const struct value
*v
)
588 gdb_assert (v
->lval
== lval_computed
);
590 return v
->location
.computed
.closure
;
594 deprecated_value_lval_hack (struct value
*value
)
600 value_address (struct value
*value
)
602 if (value
->lval
== lval_internalvar
603 || value
->lval
== lval_internalvar_component
)
605 return value
->location
.address
+ value
->offset
;
609 value_raw_address (struct value
*value
)
611 if (value
->lval
== lval_internalvar
612 || value
->lval
== lval_internalvar_component
)
614 return value
->location
.address
;
618 set_value_address (struct value
*value
, CORE_ADDR addr
)
620 gdb_assert (value
->lval
!= lval_internalvar
621 && value
->lval
!= lval_internalvar_component
);
622 value
->location
.address
= addr
;
625 struct internalvar
**
626 deprecated_value_internalvar_hack (struct value
*value
)
628 return &value
->location
.internalvar
;
632 deprecated_value_frame_id_hack (struct value
*value
)
634 return &value
->frame_id
;
638 deprecated_value_regnum_hack (struct value
*value
)
640 return &value
->regnum
;
644 deprecated_value_modifiable (struct value
*value
)
646 return value
->modifiable
;
649 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
651 value
->modifiable
= modifiable
;
654 /* Return a mark in the value chain. All values allocated after the
655 mark is obtained (except for those released) are subject to being freed
656 if a subsequent value_free_to_mark is passed the mark. */
663 /* Take a reference to VAL. VAL will not be deallocated until all
664 references are released. */
667 value_incref (struct value
*val
)
669 val
->reference_count
++;
672 /* Release a reference to VAL, which was acquired with value_incref.
673 This function is also called to deallocate values from the value
677 value_free (struct value
*val
)
681 gdb_assert (val
->reference_count
> 0);
682 val
->reference_count
--;
683 if (val
->reference_count
> 0)
686 /* If there's an associated parent value, drop our reference to
688 if (val
->parent
!= NULL
)
689 value_free (val
->parent
);
691 if (VALUE_LVAL (val
) == lval_computed
)
693 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
695 if (funcs
->free_closure
)
696 funcs
->free_closure (val
);
699 xfree (val
->contents
);
704 /* Free all values allocated since MARK was obtained by value_mark
705 (except for those released). */
707 value_free_to_mark (struct value
*mark
)
712 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
720 /* Free all the values that have been allocated (except for those released).
721 Call after each command, successful or not.
722 In practice this is called before each command, which is sufficient. */
725 free_all_values (void)
730 for (val
= all_values
; val
; val
= next
)
739 /* Frees all the elements in a chain of values. */
742 free_value_chain (struct value
*v
)
748 next
= value_next (v
);
753 /* Remove VAL from the chain all_values
754 so it will not be freed automatically. */
757 release_value (struct value
*val
)
761 if (all_values
== val
)
763 all_values
= val
->next
;
768 for (v
= all_values
; v
; v
= v
->next
)
779 /* Release all values up to mark */
781 value_release_to_mark (struct value
*mark
)
786 for (val
= next
= all_values
; next
; next
= next
->next
)
787 if (next
->next
== mark
)
789 all_values
= next
->next
;
797 /* Return a copy of the value ARG.
798 It contains the same contents, for same memory address,
799 but it's a different block of storage. */
802 value_copy (struct value
*arg
)
804 struct type
*encl_type
= value_enclosing_type (arg
);
807 if (value_lazy (arg
))
808 val
= allocate_value_lazy (encl_type
);
810 val
= allocate_value (encl_type
);
811 val
->type
= arg
->type
;
812 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
813 val
->location
= arg
->location
;
814 val
->offset
= arg
->offset
;
815 val
->bitpos
= arg
->bitpos
;
816 val
->bitsize
= arg
->bitsize
;
817 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
818 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
819 val
->lazy
= arg
->lazy
;
820 val
->optimized_out
= arg
->optimized_out
;
821 val
->embedded_offset
= value_embedded_offset (arg
);
822 val
->pointed_to_offset
= arg
->pointed_to_offset
;
823 val
->modifiable
= arg
->modifiable
;
824 if (!value_lazy (val
))
826 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
827 TYPE_LENGTH (value_enclosing_type (arg
)));
830 val
->parent
= arg
->parent
;
832 value_incref (val
->parent
);
833 if (VALUE_LVAL (val
) == lval_computed
)
835 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
837 if (funcs
->copy_closure
)
838 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
843 /* Return a version of ARG that is non-lvalue. */
846 value_non_lval (struct value
*arg
)
848 if (VALUE_LVAL (arg
) != not_lval
)
850 struct type
*enc_type
= value_enclosing_type (arg
);
851 struct value
*val
= allocate_value (enc_type
);
853 memcpy (value_contents_all_raw (val
), value_contents_all (arg
),
854 TYPE_LENGTH (enc_type
));
855 val
->type
= arg
->type
;
856 set_value_embedded_offset (val
, value_embedded_offset (arg
));
857 set_value_pointed_to_offset (val
, value_pointed_to_offset (arg
));
864 set_value_component_location (struct value
*component
,
865 const struct value
*whole
)
867 if (whole
->lval
== lval_internalvar
)
868 VALUE_LVAL (component
) = lval_internalvar_component
;
870 VALUE_LVAL (component
) = whole
->lval
;
872 component
->location
= whole
->location
;
873 if (whole
->lval
== lval_computed
)
875 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
877 if (funcs
->copy_closure
)
878 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
883 /* Access to the value history. */
885 /* Record a new value in the value history.
886 Returns the absolute history index of the entry.
887 Result of -1 indicates the value was not saved; otherwise it is the
888 value history index of this new item. */
891 record_latest_value (struct value
*val
)
895 /* We don't want this value to have anything to do with the inferior anymore.
896 In particular, "set $1 = 50" should not affect the variable from which
897 the value was taken, and fast watchpoints should be able to assume that
898 a value on the value history never changes. */
899 if (value_lazy (val
))
900 value_fetch_lazy (val
);
901 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
902 from. This is a bit dubious, because then *&$1 does not just return $1
903 but the current contents of that location. c'est la vie... */
907 /* Here we treat value_history_count as origin-zero
908 and applying to the value being stored now. */
910 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
913 struct value_history_chunk
*new
914 = (struct value_history_chunk
*)
916 xmalloc (sizeof (struct value_history_chunk
));
917 memset (new->values
, 0, sizeof new->values
);
918 new->next
= value_history_chain
;
919 value_history_chain
= new;
922 value_history_chain
->values
[i
] = val
;
924 /* Now we regard value_history_count as origin-one
925 and applying to the value just stored. */
927 return ++value_history_count
;
930 /* Return a copy of the value in the history with sequence number NUM. */
933 access_value_history (int num
)
935 struct value_history_chunk
*chunk
;
940 absnum
+= value_history_count
;
945 error (_("The history is empty."));
947 error (_("There is only one value in the history."));
949 error (_("History does not go back to $$%d."), -num
);
951 if (absnum
> value_history_count
)
952 error (_("History has not yet reached $%d."), absnum
);
956 /* Now absnum is always absolute and origin zero. */
958 chunk
= value_history_chain
;
959 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
960 - absnum
/ VALUE_HISTORY_CHUNK
;
964 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
968 show_values (char *num_exp
, int from_tty
)
976 /* "show values +" should print from the stored position.
977 "show values <exp>" should print around value number <exp>. */
978 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
979 num
= parse_and_eval_long (num_exp
) - 5;
983 /* "show values" means print the last 10 values. */
984 num
= value_history_count
- 9;
990 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
992 struct value_print_options opts
;
994 val
= access_value_history (i
);
995 printf_filtered (("$%d = "), i
);
996 get_user_print_options (&opts
);
997 value_print (val
, gdb_stdout
, &opts
);
998 printf_filtered (("\n"));
1001 /* The next "show values +" should start after what we just printed. */
1004 /* Hitting just return after this command should do the same thing as
1005 "show values +". If num_exp is null, this is unnecessary, since
1006 "show values +" is not useful after "show values". */
1007 if (from_tty
&& num_exp
)
1014 /* Internal variables. These are variables within the debugger
1015 that hold values assigned by debugger commands.
1016 The user refers to them with a '$' prefix
1017 that does not appear in the variable names stored internally. */
1021 struct internalvar
*next
;
1024 /* We support various different kinds of content of an internal variable.
1025 enum internalvar_kind specifies the kind, and union internalvar_data
1026 provides the data associated with this particular kind. */
1028 enum internalvar_kind
1030 /* The internal variable is empty. */
1033 /* The value of the internal variable is provided directly as
1034 a GDB value object. */
1037 /* A fresh value is computed via a call-back routine on every
1038 access to the internal variable. */
1039 INTERNALVAR_MAKE_VALUE
,
1041 /* The internal variable holds a GDB internal convenience function. */
1042 INTERNALVAR_FUNCTION
,
1044 /* The variable holds an integer value. */
1045 INTERNALVAR_INTEGER
,
1047 /* The variable holds a pointer value. */
1048 INTERNALVAR_POINTER
,
1050 /* The variable holds a GDB-provided string. */
1055 union internalvar_data
1057 /* A value object used with INTERNALVAR_VALUE. */
1058 struct value
*value
;
1060 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1061 internalvar_make_value make_value
;
1063 /* The internal function used with INTERNALVAR_FUNCTION. */
1066 struct internal_function
*function
;
1067 /* True if this is the canonical name for the function. */
1071 /* An integer value used with INTERNALVAR_INTEGER. */
1074 /* If type is non-NULL, it will be used as the type to generate
1075 a value for this internal variable. If type is NULL, a default
1076 integer type for the architecture is used. */
1081 /* A pointer value used with INTERNALVAR_POINTER. */
1088 /* A string value used with INTERNALVAR_STRING. */
1093 static struct internalvar
*internalvars
;
1095 /* If the variable does not already exist create it and give it the
1096 value given. If no value is given then the default is zero. */
1098 init_if_undefined_command (char* args
, int from_tty
)
1100 struct internalvar
* intvar
;
1102 /* Parse the expression - this is taken from set_command(). */
1103 struct expression
*expr
= parse_expression (args
);
1104 register struct cleanup
*old_chain
=
1105 make_cleanup (free_current_contents
, &expr
);
1107 /* Validate the expression.
1108 Was the expression an assignment?
1109 Or even an expression at all? */
1110 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1111 error (_("Init-if-undefined requires an assignment expression."));
1113 /* Extract the variable from the parsed expression.
1114 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1115 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1116 error (_("The first parameter to init-if-undefined "
1117 "should be a GDB variable."));
1118 intvar
= expr
->elts
[2].internalvar
;
1120 /* Only evaluate the expression if the lvalue is void.
1121 This may still fail if the expresssion is invalid. */
1122 if (intvar
->kind
== INTERNALVAR_VOID
)
1123 evaluate_expression (expr
);
1125 do_cleanups (old_chain
);
1129 /* Look up an internal variable with name NAME. NAME should not
1130 normally include a dollar sign.
1132 If the specified internal variable does not exist,
1133 the return value is NULL. */
1135 struct internalvar
*
1136 lookup_only_internalvar (const char *name
)
1138 struct internalvar
*var
;
1140 for (var
= internalvars
; var
; var
= var
->next
)
1141 if (strcmp (var
->name
, name
) == 0)
1148 /* Create an internal variable with name NAME and with a void value.
1149 NAME should not normally include a dollar sign. */
1151 struct internalvar
*
1152 create_internalvar (const char *name
)
1154 struct internalvar
*var
;
1156 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1157 var
->name
= concat (name
, (char *)NULL
);
1158 var
->kind
= INTERNALVAR_VOID
;
1159 var
->next
= internalvars
;
1164 /* Create an internal variable with name NAME and register FUN as the
1165 function that value_of_internalvar uses to create a value whenever
1166 this variable is referenced. NAME should not normally include a
1169 struct internalvar
*
1170 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1172 struct internalvar
*var
= create_internalvar (name
);
1174 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1175 var
->u
.make_value
= fun
;
1179 /* Look up an internal variable with name NAME. NAME should not
1180 normally include a dollar sign.
1182 If the specified internal variable does not exist,
1183 one is created, with a void value. */
1185 struct internalvar
*
1186 lookup_internalvar (const char *name
)
1188 struct internalvar
*var
;
1190 var
= lookup_only_internalvar (name
);
1194 return create_internalvar (name
);
1197 /* Return current value of internal variable VAR. For variables that
1198 are not inherently typed, use a value type appropriate for GDBARCH. */
1201 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1204 struct trace_state_variable
*tsv
;
1206 /* If there is a trace state variable of the same name, assume that
1207 is what we really want to see. */
1208 tsv
= find_trace_state_variable (var
->name
);
1211 tsv
->value_known
= target_get_trace_state_variable_value (tsv
->number
,
1213 if (tsv
->value_known
)
1214 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int64
,
1217 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1223 case INTERNALVAR_VOID
:
1224 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1227 case INTERNALVAR_FUNCTION
:
1228 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1231 case INTERNALVAR_INTEGER
:
1232 if (!var
->u
.integer
.type
)
1233 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1234 var
->u
.integer
.val
);
1236 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1239 case INTERNALVAR_POINTER
:
1240 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1243 case INTERNALVAR_STRING
:
1244 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1245 builtin_type (gdbarch
)->builtin_char
);
1248 case INTERNALVAR_VALUE
:
1249 val
= value_copy (var
->u
.value
);
1250 if (value_lazy (val
))
1251 value_fetch_lazy (val
);
1254 case INTERNALVAR_MAKE_VALUE
:
1255 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1259 internal_error (__FILE__
, __LINE__
, "bad kind");
1262 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1263 on this value go back to affect the original internal variable.
1265 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1266 no underlying modifyable state in the internal variable.
1268 Likewise, if the variable's value is a computed lvalue, we want
1269 references to it to produce another computed lvalue, where
1270 references and assignments actually operate through the
1271 computed value's functions.
1273 This means that internal variables with computed values
1274 behave a little differently from other internal variables:
1275 assignments to them don't just replace the previous value
1276 altogether. At the moment, this seems like the behavior we
1279 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1280 && val
->lval
!= lval_computed
)
1282 VALUE_LVAL (val
) = lval_internalvar
;
1283 VALUE_INTERNALVAR (val
) = var
;
1290 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1294 case INTERNALVAR_INTEGER
:
1295 *result
= var
->u
.integer
.val
;
1304 get_internalvar_function (struct internalvar
*var
,
1305 struct internal_function
**result
)
1309 case INTERNALVAR_FUNCTION
:
1310 *result
= var
->u
.fn
.function
;
1319 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1320 int bitsize
, struct value
*newval
)
1326 case INTERNALVAR_VALUE
:
1327 addr
= value_contents_writeable (var
->u
.value
);
1330 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1331 value_as_long (newval
), bitpos
, bitsize
);
1333 memcpy (addr
+ offset
, value_contents (newval
),
1334 TYPE_LENGTH (value_type (newval
)));
1338 /* We can never get a component of any other kind. */
1339 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1344 set_internalvar (struct internalvar
*var
, struct value
*val
)
1346 enum internalvar_kind new_kind
;
1347 union internalvar_data new_data
= { 0 };
1349 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1350 error (_("Cannot overwrite convenience function %s"), var
->name
);
1352 /* Prepare new contents. */
1353 switch (TYPE_CODE (check_typedef (value_type (val
))))
1355 case TYPE_CODE_VOID
:
1356 new_kind
= INTERNALVAR_VOID
;
1359 case TYPE_CODE_INTERNAL_FUNCTION
:
1360 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1361 new_kind
= INTERNALVAR_FUNCTION
;
1362 get_internalvar_function (VALUE_INTERNALVAR (val
),
1363 &new_data
.fn
.function
);
1364 /* Copies created here are never canonical. */
1368 new_kind
= INTERNALVAR_INTEGER
;
1369 new_data
.integer
.type
= value_type (val
);
1370 new_data
.integer
.val
= value_as_long (val
);
1374 new_kind
= INTERNALVAR_POINTER
;
1375 new_data
.pointer
.type
= value_type (val
);
1376 new_data
.pointer
.val
= value_as_address (val
);
1380 new_kind
= INTERNALVAR_VALUE
;
1381 new_data
.value
= value_copy (val
);
1382 new_data
.value
->modifiable
= 1;
1384 /* Force the value to be fetched from the target now, to avoid problems
1385 later when this internalvar is referenced and the target is gone or
1387 if (value_lazy (new_data
.value
))
1388 value_fetch_lazy (new_data
.value
);
1390 /* Release the value from the value chain to prevent it from being
1391 deleted by free_all_values. From here on this function should not
1392 call error () until new_data is installed into the var->u to avoid
1394 release_value (new_data
.value
);
1398 /* Clean up old contents. */
1399 clear_internalvar (var
);
1402 var
->kind
= new_kind
;
1404 /* End code which must not call error(). */
1408 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1410 /* Clean up old contents. */
1411 clear_internalvar (var
);
1413 var
->kind
= INTERNALVAR_INTEGER
;
1414 var
->u
.integer
.type
= NULL
;
1415 var
->u
.integer
.val
= l
;
1419 set_internalvar_string (struct internalvar
*var
, const char *string
)
1421 /* Clean up old contents. */
1422 clear_internalvar (var
);
1424 var
->kind
= INTERNALVAR_STRING
;
1425 var
->u
.string
= xstrdup (string
);
1429 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1431 /* Clean up old contents. */
1432 clear_internalvar (var
);
1434 var
->kind
= INTERNALVAR_FUNCTION
;
1435 var
->u
.fn
.function
= f
;
1436 var
->u
.fn
.canonical
= 1;
1437 /* Variables installed here are always the canonical version. */
1441 clear_internalvar (struct internalvar
*var
)
1443 /* Clean up old contents. */
1446 case INTERNALVAR_VALUE
:
1447 value_free (var
->u
.value
);
1450 case INTERNALVAR_STRING
:
1451 xfree (var
->u
.string
);
1458 /* Reset to void kind. */
1459 var
->kind
= INTERNALVAR_VOID
;
1463 internalvar_name (struct internalvar
*var
)
1468 static struct internal_function
*
1469 create_internal_function (const char *name
,
1470 internal_function_fn handler
, void *cookie
)
1472 struct internal_function
*ifn
= XNEW (struct internal_function
);
1474 ifn
->name
= xstrdup (name
);
1475 ifn
->handler
= handler
;
1476 ifn
->cookie
= cookie
;
1481 value_internal_function_name (struct value
*val
)
1483 struct internal_function
*ifn
;
1486 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1487 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1488 gdb_assert (result
);
1494 call_internal_function (struct gdbarch
*gdbarch
,
1495 const struct language_defn
*language
,
1496 struct value
*func
, int argc
, struct value
**argv
)
1498 struct internal_function
*ifn
;
1501 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1502 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1503 gdb_assert (result
);
1505 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1508 /* The 'function' command. This does nothing -- it is just a
1509 placeholder to let "help function NAME" work. This is also used as
1510 the implementation of the sub-command that is created when
1511 registering an internal function. */
1513 function_command (char *command
, int from_tty
)
1518 /* Clean up if an internal function's command is destroyed. */
1520 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1526 /* Add a new internal function. NAME is the name of the function; DOC
1527 is a documentation string describing the function. HANDLER is
1528 called when the function is invoked. COOKIE is an arbitrary
1529 pointer which is passed to HANDLER and is intended for "user
1532 add_internal_function (const char *name
, const char *doc
,
1533 internal_function_fn handler
, void *cookie
)
1535 struct cmd_list_element
*cmd
;
1536 struct internal_function
*ifn
;
1537 struct internalvar
*var
= lookup_internalvar (name
);
1539 ifn
= create_internal_function (name
, handler
, cookie
);
1540 set_internalvar_function (var
, ifn
);
1542 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1544 cmd
->destroyer
= function_destroyer
;
1547 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1548 prevent cycles / duplicates. */
1551 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1552 htab_t copied_types
)
1554 if (TYPE_OBJFILE (value
->type
) == objfile
)
1555 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1557 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1558 value
->enclosing_type
= copy_type_recursive (objfile
,
1559 value
->enclosing_type
,
1563 /* Likewise for internal variable VAR. */
1566 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1567 htab_t copied_types
)
1571 case INTERNALVAR_INTEGER
:
1572 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1574 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1577 case INTERNALVAR_POINTER
:
1578 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1580 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1583 case INTERNALVAR_VALUE
:
1584 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1589 /* Update the internal variables and value history when OBJFILE is
1590 discarded; we must copy the types out of the objfile. New global types
1591 will be created for every convenience variable which currently points to
1592 this objfile's types, and the convenience variables will be adjusted to
1593 use the new global types. */
1596 preserve_values (struct objfile
*objfile
)
1598 htab_t copied_types
;
1599 struct value_history_chunk
*cur
;
1600 struct internalvar
*var
;
1603 /* Create the hash table. We allocate on the objfile's obstack, since
1604 it is soon to be deleted. */
1605 copied_types
= create_copied_types_hash (objfile
);
1607 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1608 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1610 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1612 for (var
= internalvars
; var
; var
= var
->next
)
1613 preserve_one_internalvar (var
, objfile
, copied_types
);
1615 preserve_python_values (objfile
, copied_types
);
1617 htab_delete (copied_types
);
1621 show_convenience (char *ignore
, int from_tty
)
1623 struct gdbarch
*gdbarch
= get_current_arch ();
1624 struct internalvar
*var
;
1626 struct value_print_options opts
;
1628 get_user_print_options (&opts
);
1629 for (var
= internalvars
; var
; var
= var
->next
)
1635 printf_filtered (("$%s = "), var
->name
);
1636 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1638 printf_filtered (("\n"));
1641 printf_unfiltered (_("No debugger convenience variables now defined.\n"
1642 "Convenience variables have "
1643 "names starting with \"$\";\n"
1644 "use \"set\" as in \"set "
1645 "$foo = 5\" to define them.\n"));
1648 /* Extract a value as a C number (either long or double).
1649 Knows how to convert fixed values to double, or
1650 floating values to long.
1651 Does not deallocate the value. */
1654 value_as_long (struct value
*val
)
1656 /* This coerces arrays and functions, which is necessary (e.g.
1657 in disassemble_command). It also dereferences references, which
1658 I suspect is the most logical thing to do. */
1659 val
= coerce_array (val
);
1660 return unpack_long (value_type (val
), value_contents (val
));
1664 value_as_double (struct value
*val
)
1669 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1671 error (_("Invalid floating value found in program."));
1675 /* Extract a value as a C pointer. Does not deallocate the value.
1676 Note that val's type may not actually be a pointer; value_as_long
1677 handles all the cases. */
1679 value_as_address (struct value
*val
)
1681 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1683 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1684 whether we want this to be true eventually. */
1686 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1687 non-address (e.g. argument to "signal", "info break", etc.), or
1688 for pointers to char, in which the low bits *are* significant. */
1689 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1692 /* There are several targets (IA-64, PowerPC, and others) which
1693 don't represent pointers to functions as simply the address of
1694 the function's entry point. For example, on the IA-64, a
1695 function pointer points to a two-word descriptor, generated by
1696 the linker, which contains the function's entry point, and the
1697 value the IA-64 "global pointer" register should have --- to
1698 support position-independent code. The linker generates
1699 descriptors only for those functions whose addresses are taken.
1701 On such targets, it's difficult for GDB to convert an arbitrary
1702 function address into a function pointer; it has to either find
1703 an existing descriptor for that function, or call malloc and
1704 build its own. On some targets, it is impossible for GDB to
1705 build a descriptor at all: the descriptor must contain a jump
1706 instruction; data memory cannot be executed; and code memory
1709 Upon entry to this function, if VAL is a value of type `function'
1710 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1711 value_address (val) is the address of the function. This is what
1712 you'll get if you evaluate an expression like `main'. The call
1713 to COERCE_ARRAY below actually does all the usual unary
1714 conversions, which includes converting values of type `function'
1715 to `pointer to function'. This is the challenging conversion
1716 discussed above. Then, `unpack_long' will convert that pointer
1717 back into an address.
1719 So, suppose the user types `disassemble foo' on an architecture
1720 with a strange function pointer representation, on which GDB
1721 cannot build its own descriptors, and suppose further that `foo'
1722 has no linker-built descriptor. The address->pointer conversion
1723 will signal an error and prevent the command from running, even
1724 though the next step would have been to convert the pointer
1725 directly back into the same address.
1727 The following shortcut avoids this whole mess. If VAL is a
1728 function, just return its address directly. */
1729 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1730 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1731 return value_address (val
);
1733 val
= coerce_array (val
);
1735 /* Some architectures (e.g. Harvard), map instruction and data
1736 addresses onto a single large unified address space. For
1737 instance: An architecture may consider a large integer in the
1738 range 0x10000000 .. 0x1000ffff to already represent a data
1739 addresses (hence not need a pointer to address conversion) while
1740 a small integer would still need to be converted integer to
1741 pointer to address. Just assume such architectures handle all
1742 integer conversions in a single function. */
1746 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1747 must admonish GDB hackers to make sure its behavior matches the
1748 compiler's, whenever possible.
1750 In general, I think GDB should evaluate expressions the same way
1751 the compiler does. When the user copies an expression out of
1752 their source code and hands it to a `print' command, they should
1753 get the same value the compiler would have computed. Any
1754 deviation from this rule can cause major confusion and annoyance,
1755 and needs to be justified carefully. In other words, GDB doesn't
1756 really have the freedom to do these conversions in clever and
1759 AndrewC pointed out that users aren't complaining about how GDB
1760 casts integers to pointers; they are complaining that they can't
1761 take an address from a disassembly listing and give it to `x/i'.
1762 This is certainly important.
1764 Adding an architecture method like integer_to_address() certainly
1765 makes it possible for GDB to "get it right" in all circumstances
1766 --- the target has complete control over how things get done, so
1767 people can Do The Right Thing for their target without breaking
1768 anyone else. The standard doesn't specify how integers get
1769 converted to pointers; usually, the ABI doesn't either, but
1770 ABI-specific code is a more reasonable place to handle it. */
1772 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1773 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1774 && gdbarch_integer_to_address_p (gdbarch
))
1775 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1776 value_contents (val
));
1778 return unpack_long (value_type (val
), value_contents (val
));
1782 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1783 as a long, or as a double, assuming the raw data is described
1784 by type TYPE. Knows how to convert different sizes of values
1785 and can convert between fixed and floating point. We don't assume
1786 any alignment for the raw data. Return value is in host byte order.
1788 If you want functions and arrays to be coerced to pointers, and
1789 references to be dereferenced, call value_as_long() instead.
1791 C++: It is assumed that the front-end has taken care of
1792 all matters concerning pointers to members. A pointer
1793 to member which reaches here is considered to be equivalent
1794 to an INT (or some size). After all, it is only an offset. */
1797 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1799 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1800 enum type_code code
= TYPE_CODE (type
);
1801 int len
= TYPE_LENGTH (type
);
1802 int nosign
= TYPE_UNSIGNED (type
);
1806 case TYPE_CODE_TYPEDEF
:
1807 return unpack_long (check_typedef (type
), valaddr
);
1808 case TYPE_CODE_ENUM
:
1809 case TYPE_CODE_FLAGS
:
1810 case TYPE_CODE_BOOL
:
1812 case TYPE_CODE_CHAR
:
1813 case TYPE_CODE_RANGE
:
1814 case TYPE_CODE_MEMBERPTR
:
1816 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1818 return extract_signed_integer (valaddr
, len
, byte_order
);
1821 return extract_typed_floating (valaddr
, type
);
1823 case TYPE_CODE_DECFLOAT
:
1824 /* libdecnumber has a function to convert from decimal to integer, but
1825 it doesn't work when the decimal number has a fractional part. */
1826 return decimal_to_doublest (valaddr
, len
, byte_order
);
1830 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1831 whether we want this to be true eventually. */
1832 return extract_typed_address (valaddr
, type
);
1835 error (_("Value can't be converted to integer."));
1837 return 0; /* Placate lint. */
1840 /* Return a double value from the specified type and address.
1841 INVP points to an int which is set to 0 for valid value,
1842 1 for invalid value (bad float format). In either case,
1843 the returned double is OK to use. Argument is in target
1844 format, result is in host format. */
1847 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1849 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1850 enum type_code code
;
1854 *invp
= 0; /* Assume valid. */
1855 CHECK_TYPEDEF (type
);
1856 code
= TYPE_CODE (type
);
1857 len
= TYPE_LENGTH (type
);
1858 nosign
= TYPE_UNSIGNED (type
);
1859 if (code
== TYPE_CODE_FLT
)
1861 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1862 floating-point value was valid (using the macro
1863 INVALID_FLOAT). That test/macro have been removed.
1865 It turns out that only the VAX defined this macro and then
1866 only in a non-portable way. Fixing the portability problem
1867 wouldn't help since the VAX floating-point code is also badly
1868 bit-rotten. The target needs to add definitions for the
1869 methods gdbarch_float_format and gdbarch_double_format - these
1870 exactly describe the target floating-point format. The
1871 problem here is that the corresponding floatformat_vax_f and
1872 floatformat_vax_d values these methods should be set to are
1873 also not defined either. Oops!
1875 Hopefully someone will add both the missing floatformat
1876 definitions and the new cases for floatformat_is_valid (). */
1878 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1884 return extract_typed_floating (valaddr
, type
);
1886 else if (code
== TYPE_CODE_DECFLOAT
)
1887 return decimal_to_doublest (valaddr
, len
, byte_order
);
1890 /* Unsigned -- be sure we compensate for signed LONGEST. */
1891 return (ULONGEST
) unpack_long (type
, valaddr
);
1895 /* Signed -- we are OK with unpack_long. */
1896 return unpack_long (type
, valaddr
);
1900 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1901 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1902 We don't assume any alignment for the raw data. Return value is in
1905 If you want functions and arrays to be coerced to pointers, and
1906 references to be dereferenced, call value_as_address() instead.
1908 C++: It is assumed that the front-end has taken care of
1909 all matters concerning pointers to members. A pointer
1910 to member which reaches here is considered to be equivalent
1911 to an INT (or some size). After all, it is only an offset. */
1914 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1916 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1917 whether we want this to be true eventually. */
1918 return unpack_long (type
, valaddr
);
1922 /* Get the value of the FIELDNO'th field (which must be static) of
1923 TYPE. Return NULL if the field doesn't exist or has been
1927 value_static_field (struct type
*type
, int fieldno
)
1929 struct value
*retval
;
1931 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
1933 case FIELD_LOC_KIND_PHYSADDR
:
1934 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1935 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1937 case FIELD_LOC_KIND_PHYSNAME
:
1939 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1940 /*TYPE_FIELD_NAME (type, fieldno);*/
1941 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1945 /* With some compilers, e.g. HP aCC, static data members are
1946 reported as non-debuggable symbols */
1947 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1954 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1955 SYMBOL_VALUE_ADDRESS (msym
));
1959 retval
= value_of_variable (sym
, NULL
);
1963 gdb_assert_not_reached ("unexpected field location kind");
1969 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1970 You have to be careful here, since the size of the data area for the value
1971 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1972 than the old enclosing type, you have to allocate more space for the
1976 set_value_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1978 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1980 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1982 val
->enclosing_type
= new_encl_type
;
1985 /* Given a value ARG1 (offset by OFFSET bytes)
1986 of a struct or union type ARG_TYPE,
1987 extract and return the value of one of its (non-static) fields.
1988 FIELDNO says which field. */
1991 value_primitive_field (struct value
*arg1
, int offset
,
1992 int fieldno
, struct type
*arg_type
)
1997 CHECK_TYPEDEF (arg_type
);
1998 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
2000 /* Call check_typedef on our type to make sure that, if TYPE
2001 is a TYPE_CODE_TYPEDEF, its length is set to the length
2002 of the target type instead of zero. However, we do not
2003 replace the typedef type by the target type, because we want
2004 to keep the typedef in order to be able to print the type
2005 description correctly. */
2006 check_typedef (type
);
2008 /* Handle packed fields */
2010 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
2012 /* Create a new value for the bitfield, with bitpos and bitsize
2013 set. If possible, arrange offset and bitpos so that we can
2014 do a single aligned read of the size of the containing type.
2015 Otherwise, adjust offset to the byte containing the first
2016 bit. Assume that the address, offset, and embedded offset
2017 are sufficiently aligned. */
2018 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
2019 int container_bitsize
= TYPE_LENGTH (type
) * 8;
2021 v
= allocate_value_lazy (type
);
2022 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
2023 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
2024 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
2025 v
->bitpos
= bitpos
% container_bitsize
;
2027 v
->bitpos
= bitpos
% 8;
2028 v
->offset
= (value_embedded_offset (arg1
)
2030 + (bitpos
- v
->bitpos
) / 8);
2032 value_incref (v
->parent
);
2033 if (!value_lazy (arg1
))
2034 value_fetch_lazy (v
);
2036 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
2038 /* This field is actually a base subobject, so preserve the
2039 entire object's contents for later references to virtual
2042 /* Lazy register values with offsets are not supported. */
2043 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2044 value_fetch_lazy (arg1
);
2046 if (value_lazy (arg1
))
2047 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2050 v
= allocate_value (value_enclosing_type (arg1
));
2051 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2052 TYPE_LENGTH (value_enclosing_type (arg1
)));
2055 v
->offset
= value_offset (arg1
);
2056 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2057 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2061 /* Plain old data member */
2062 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2064 /* Lazy register values with offsets are not supported. */
2065 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2066 value_fetch_lazy (arg1
);
2068 if (value_lazy (arg1
))
2069 v
= allocate_value_lazy (type
);
2072 v
= allocate_value (type
);
2073 memcpy (value_contents_raw (v
),
2074 value_contents_raw (arg1
) + offset
,
2075 TYPE_LENGTH (type
));
2077 v
->offset
= (value_offset (arg1
) + offset
2078 + value_embedded_offset (arg1
));
2080 set_value_component_location (v
, arg1
);
2081 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2082 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2086 /* Given a value ARG1 of a struct or union type,
2087 extract and return the value of one of its (non-static) fields.
2088 FIELDNO says which field. */
2091 value_field (struct value
*arg1
, int fieldno
)
2093 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2096 /* Return a non-virtual function as a value.
2097 F is the list of member functions which contains the desired method.
2098 J is an index into F which provides the desired method.
2100 We only use the symbol for its address, so be happy with either a
2101 full symbol or a minimal symbol.
2105 value_fn_field (struct value
**arg1p
, struct fn_field
*f
,
2106 int j
, struct type
*type
,
2110 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2111 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2113 struct minimal_symbol
*msym
;
2115 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2122 gdb_assert (sym
== NULL
);
2123 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2128 v
= allocate_value (ftype
);
2131 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2135 /* The minimal symbol might point to a function descriptor;
2136 resolve it to the actual code address instead. */
2137 struct objfile
*objfile
= msymbol_objfile (msym
);
2138 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2140 set_value_address (v
,
2141 gdbarch_convert_from_func_ptr_addr
2142 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2147 if (type
!= value_type (*arg1p
))
2148 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2149 value_addr (*arg1p
)));
2151 /* Move the `this' pointer according to the offset.
2152 VALUE_OFFSET (*arg1p) += offset;
2160 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2161 object at VALADDR. The bitfield starts at BITPOS bits and contains
2164 Extracting bits depends on endianness of the machine. Compute the
2165 number of least significant bits to discard. For big endian machines,
2166 we compute the total number of bits in the anonymous object, subtract
2167 off the bit count from the MSB of the object to the MSB of the
2168 bitfield, then the size of the bitfield, which leaves the LSB discard
2169 count. For little endian machines, the discard count is simply the
2170 number of bits from the LSB of the anonymous object to the LSB of the
2173 If the field is signed, we also do sign extension. */
2176 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2177 int bitpos
, int bitsize
)
2179 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2185 /* Read the minimum number of bytes required; there may not be
2186 enough bytes to read an entire ULONGEST. */
2187 CHECK_TYPEDEF (field_type
);
2189 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2191 bytes_read
= TYPE_LENGTH (field_type
);
2193 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2194 bytes_read
, byte_order
);
2196 /* Extract bits. See comment above. */
2198 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2199 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2201 lsbcount
= (bitpos
% 8);
2204 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2205 If the field is signed, and is negative, then sign extend. */
2207 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2209 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2211 if (!TYPE_UNSIGNED (field_type
))
2213 if (val
& (valmask
^ (valmask
>> 1)))
2222 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2223 VALADDR. See unpack_bits_as_long for more details. */
2226 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2228 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2229 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2230 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2232 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2235 /* Modify the value of a bitfield. ADDR points to a block of memory in
2236 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2237 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2238 indicate which bits (in target bit order) comprise the bitfield.
2239 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
2240 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2243 modify_field (struct type
*type
, gdb_byte
*addr
,
2244 LONGEST fieldval
, int bitpos
, int bitsize
)
2246 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2248 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2251 /* Normalize BITPOS. */
2255 /* If a negative fieldval fits in the field in question, chop
2256 off the sign extension bits. */
2257 if ((~fieldval
& ~(mask
>> 1)) == 0)
2260 /* Warn if value is too big to fit in the field in question. */
2261 if (0 != (fieldval
& ~mask
))
2263 /* FIXME: would like to include fieldval in the message, but
2264 we don't have a sprintf_longest. */
2265 warning (_("Value does not fit in %d bits."), bitsize
);
2267 /* Truncate it, otherwise adjoining fields may be corrupted. */
2271 /* Ensure no bytes outside of the modified ones get accessed as it may cause
2272 false valgrind reports. */
2274 bytesize
= (bitpos
+ bitsize
+ 7) / 8;
2275 oword
= extract_unsigned_integer (addr
, bytesize
, byte_order
);
2277 /* Shifting for bit field depends on endianness of the target machine. */
2278 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2279 bitpos
= bytesize
* 8 - bitpos
- bitsize
;
2281 oword
&= ~(mask
<< bitpos
);
2282 oword
|= fieldval
<< bitpos
;
2284 store_unsigned_integer (addr
, bytesize
, byte_order
, oword
);
2287 /* Pack NUM into BUF using a target format of TYPE. */
2290 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2292 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2295 type
= check_typedef (type
);
2296 len
= TYPE_LENGTH (type
);
2298 switch (TYPE_CODE (type
))
2301 case TYPE_CODE_CHAR
:
2302 case TYPE_CODE_ENUM
:
2303 case TYPE_CODE_FLAGS
:
2304 case TYPE_CODE_BOOL
:
2305 case TYPE_CODE_RANGE
:
2306 case TYPE_CODE_MEMBERPTR
:
2307 store_signed_integer (buf
, len
, byte_order
, num
);
2312 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2316 error (_("Unexpected type (%d) encountered for integer constant."),
2322 /* Pack NUM into BUF using a target format of TYPE. */
2325 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2328 enum bfd_endian byte_order
;
2330 type
= check_typedef (type
);
2331 len
= TYPE_LENGTH (type
);
2332 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2334 switch (TYPE_CODE (type
))
2337 case TYPE_CODE_CHAR
:
2338 case TYPE_CODE_ENUM
:
2339 case TYPE_CODE_FLAGS
:
2340 case TYPE_CODE_BOOL
:
2341 case TYPE_CODE_RANGE
:
2342 case TYPE_CODE_MEMBERPTR
:
2343 store_unsigned_integer (buf
, len
, byte_order
, num
);
2348 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2352 error (_("Unexpected type (%d) encountered "
2353 "for unsigned integer constant."),
2359 /* Convert C numbers into newly allocated values. */
2362 value_from_longest (struct type
*type
, LONGEST num
)
2364 struct value
*val
= allocate_value (type
);
2366 pack_long (value_contents_raw (val
), type
, num
);
2371 /* Convert C unsigned numbers into newly allocated values. */
2374 value_from_ulongest (struct type
*type
, ULONGEST num
)
2376 struct value
*val
= allocate_value (type
);
2378 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2384 /* Create a value representing a pointer of type TYPE to the address
2387 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2389 struct value
*val
= allocate_value (type
);
2391 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2396 /* Create a value of type TYPE whose contents come from VALADDR, if it
2397 is non-null, and whose memory address (in the inferior) is
2401 value_from_contents_and_address (struct type
*type
,
2402 const gdb_byte
*valaddr
,
2405 struct value
*v
= allocate_value (type
);
2407 if (valaddr
== NULL
)
2408 set_value_lazy (v
, 1);
2410 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2411 set_value_address (v
, address
);
2412 VALUE_LVAL (v
) = lval_memory
;
2417 value_from_double (struct type
*type
, DOUBLEST num
)
2419 struct value
*val
= allocate_value (type
);
2420 struct type
*base_type
= check_typedef (type
);
2421 enum type_code code
= TYPE_CODE (base_type
);
2423 if (code
== TYPE_CODE_FLT
)
2425 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2428 error (_("Unexpected type encountered for floating constant."));
2434 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2436 struct value
*val
= allocate_value (type
);
2438 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2443 coerce_ref (struct value
*arg
)
2445 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2447 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2448 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2449 unpack_pointer (value_type (arg
),
2450 value_contents (arg
)));
2455 coerce_array (struct value
*arg
)
2459 arg
= coerce_ref (arg
);
2460 type
= check_typedef (value_type (arg
));
2462 switch (TYPE_CODE (type
))
2464 case TYPE_CODE_ARRAY
:
2465 if (!TYPE_VECTOR (type
) && current_language
->c_style_arrays
)
2466 arg
= value_coerce_array (arg
);
2468 case TYPE_CODE_FUNC
:
2469 arg
= value_coerce_function (arg
);
2476 /* Return true if the function returning the specified type is using
2477 the convention of returning structures in memory (passing in the
2478 address as a hidden first parameter). */
2481 using_struct_return (struct gdbarch
*gdbarch
,
2482 struct type
*func_type
, struct type
*value_type
)
2484 enum type_code code
= TYPE_CODE (value_type
);
2486 if (code
== TYPE_CODE_ERROR
)
2487 error (_("Function return type unknown."));
2489 if (code
== TYPE_CODE_VOID
)
2490 /* A void return value is never in memory. See also corresponding
2491 code in "print_return_value". */
2494 /* Probe the architecture for the return-value convention. */
2495 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2497 != RETURN_VALUE_REGISTER_CONVENTION
);
2500 /* Set the initialized field in a value struct. */
2503 set_value_initialized (struct value
*val
, int status
)
2505 val
->initialized
= status
;
2508 /* Return the initialized field in a value struct. */
2511 value_initialized (struct value
*val
)
2513 return val
->initialized
;
2517 _initialize_values (void)
2519 add_cmd ("convenience", no_class
, show_convenience
, _("\
2520 Debugger convenience (\"$foo\") variables.\n\
2521 These variables are created when you assign them values;\n\
2522 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2524 A few convenience variables are given values automatically:\n\
2525 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2526 \"$__\" holds the contents of the last address examined with \"x\"."),
2529 add_cmd ("values", no_class
, show_values
, _("\
2530 Elements of value history around item number IDX (or last ten)."),
2533 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2534 Initialize a convenience variable if necessary.\n\
2535 init-if-undefined VARIABLE = EXPRESSION\n\
2536 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2537 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2538 VARIABLE is already initialized."));
2540 add_prefix_cmd ("function", no_class
, function_command
, _("\
2541 Placeholder command for showing help on convenience functions."),
2542 &functionlist
, "function ", 0, &cmdlist
);