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 #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 $%d."), absnum
);
956 /* Now absnum is always absolute and origin zero. */
958 chunk
= value_history_chain
;
959 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
- absnum
/ VALUE_HISTORY_CHUNK
;
963 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
967 show_values (char *num_exp
, int from_tty
)
975 /* "show values +" should print from the stored position.
976 "show values <exp>" should print around value number <exp>. */
977 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
978 num
= parse_and_eval_long (num_exp
) - 5;
982 /* "show values" means print the last 10 values. */
983 num
= value_history_count
- 9;
989 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
991 struct value_print_options opts
;
993 val
= access_value_history (i
);
994 printf_filtered (("$%d = "), i
);
995 get_user_print_options (&opts
);
996 value_print (val
, gdb_stdout
, &opts
);
997 printf_filtered (("\n"));
1000 /* The next "show values +" should start after what we just printed. */
1003 /* Hitting just return after this command should do the same thing as
1004 "show values +". If num_exp is null, this is unnecessary, since
1005 "show values +" is not useful after "show values". */
1006 if (from_tty
&& num_exp
)
1013 /* Internal variables. These are variables within the debugger
1014 that hold values assigned by debugger commands.
1015 The user refers to them with a '$' prefix
1016 that does not appear in the variable names stored internally. */
1020 struct internalvar
*next
;
1023 /* We support various different kinds of content of an internal variable.
1024 enum internalvar_kind specifies the kind, and union internalvar_data
1025 provides the data associated with this particular kind. */
1027 enum internalvar_kind
1029 /* The internal variable is empty. */
1032 /* The value of the internal variable is provided directly as
1033 a GDB value object. */
1036 /* A fresh value is computed via a call-back routine on every
1037 access to the internal variable. */
1038 INTERNALVAR_MAKE_VALUE
,
1040 /* The internal variable holds a GDB internal convenience function. */
1041 INTERNALVAR_FUNCTION
,
1043 /* The variable holds an integer value. */
1044 INTERNALVAR_INTEGER
,
1046 /* The variable holds a pointer value. */
1047 INTERNALVAR_POINTER
,
1049 /* The variable holds a GDB-provided string. */
1054 union internalvar_data
1056 /* A value object used with INTERNALVAR_VALUE. */
1057 struct value
*value
;
1059 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1060 internalvar_make_value make_value
;
1062 /* The internal function used with INTERNALVAR_FUNCTION. */
1065 struct internal_function
*function
;
1066 /* True if this is the canonical name for the function. */
1070 /* An integer value used with INTERNALVAR_INTEGER. */
1073 /* If type is non-NULL, it will be used as the type to generate
1074 a value for this internal variable. If type is NULL, a default
1075 integer type for the architecture is used. */
1080 /* A pointer value used with INTERNALVAR_POINTER. */
1087 /* A string value used with INTERNALVAR_STRING. */
1092 static struct internalvar
*internalvars
;
1094 /* If the variable does not already exist create it and give it the value given.
1095 If no value is given then the default is zero. */
1097 init_if_undefined_command (char* args
, int from_tty
)
1099 struct internalvar
* intvar
;
1101 /* Parse the expression - this is taken from set_command(). */
1102 struct expression
*expr
= parse_expression (args
);
1103 register struct cleanup
*old_chain
=
1104 make_cleanup (free_current_contents
, &expr
);
1106 /* Validate the expression.
1107 Was the expression an assignment?
1108 Or even an expression at all? */
1109 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1110 error (_("Init-if-undefined requires an assignment expression."));
1112 /* Extract the variable from the parsed expression.
1113 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1114 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1115 error (_("The first parameter to init-if-undefined should be a GDB variable."));
1116 intvar
= expr
->elts
[2].internalvar
;
1118 /* Only evaluate the expression if the lvalue is void.
1119 This may still fail if the expresssion is invalid. */
1120 if (intvar
->kind
== INTERNALVAR_VOID
)
1121 evaluate_expression (expr
);
1123 do_cleanups (old_chain
);
1127 /* Look up an internal variable with name NAME. NAME should not
1128 normally include a dollar sign.
1130 If the specified internal variable does not exist,
1131 the return value is NULL. */
1133 struct internalvar
*
1134 lookup_only_internalvar (const char *name
)
1136 struct internalvar
*var
;
1138 for (var
= internalvars
; var
; var
= var
->next
)
1139 if (strcmp (var
->name
, name
) == 0)
1146 /* Create an internal variable with name NAME and with a void value.
1147 NAME should not normally include a dollar sign. */
1149 struct internalvar
*
1150 create_internalvar (const char *name
)
1152 struct internalvar
*var
;
1154 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1155 var
->name
= concat (name
, (char *)NULL
);
1156 var
->kind
= INTERNALVAR_VOID
;
1157 var
->next
= internalvars
;
1162 /* Create an internal variable with name NAME and register FUN as the
1163 function that value_of_internalvar uses to create a value whenever
1164 this variable is referenced. NAME should not normally include a
1167 struct internalvar
*
1168 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1170 struct internalvar
*var
= create_internalvar (name
);
1172 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1173 var
->u
.make_value
= fun
;
1177 /* Look up an internal variable with name NAME. NAME should not
1178 normally include a dollar sign.
1180 If the specified internal variable does not exist,
1181 one is created, with a void value. */
1183 struct internalvar
*
1184 lookup_internalvar (const char *name
)
1186 struct internalvar
*var
;
1188 var
= lookup_only_internalvar (name
);
1192 return create_internalvar (name
);
1195 /* Return current value of internal variable VAR. For variables that
1196 are not inherently typed, use a value type appropriate for GDBARCH. */
1199 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1202 struct trace_state_variable
*tsv
;
1204 /* If there is a trace state variable of the same name, assume that
1205 is what we really want to see. */
1206 tsv
= find_trace_state_variable (var
->name
);
1209 tsv
->value_known
= target_get_trace_state_variable_value (tsv
->number
,
1211 if (tsv
->value_known
)
1212 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int64
,
1215 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1221 case INTERNALVAR_VOID
:
1222 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1225 case INTERNALVAR_FUNCTION
:
1226 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1229 case INTERNALVAR_INTEGER
:
1230 if (!var
->u
.integer
.type
)
1231 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1232 var
->u
.integer
.val
);
1234 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1237 case INTERNALVAR_POINTER
:
1238 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1241 case INTERNALVAR_STRING
:
1242 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1243 builtin_type (gdbarch
)->builtin_char
);
1246 case INTERNALVAR_VALUE
:
1247 val
= value_copy (var
->u
.value
);
1248 if (value_lazy (val
))
1249 value_fetch_lazy (val
);
1252 case INTERNALVAR_MAKE_VALUE
:
1253 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1257 internal_error (__FILE__
, __LINE__
, "bad kind");
1260 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1261 on this value go back to affect the original internal variable.
1263 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1264 no underlying modifyable state in the internal variable.
1266 Likewise, if the variable's value is a computed lvalue, we want
1267 references to it to produce another computed lvalue, where
1268 references and assignments actually operate through the
1269 computed value's functions.
1271 This means that internal variables with computed values
1272 behave a little differently from other internal variables:
1273 assignments to them don't just replace the previous value
1274 altogether. At the moment, this seems like the behavior we
1277 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1278 && val
->lval
!= lval_computed
)
1280 VALUE_LVAL (val
) = lval_internalvar
;
1281 VALUE_INTERNALVAR (val
) = var
;
1288 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1292 case INTERNALVAR_INTEGER
:
1293 *result
= var
->u
.integer
.val
;
1302 get_internalvar_function (struct internalvar
*var
,
1303 struct internal_function
**result
)
1307 case INTERNALVAR_FUNCTION
:
1308 *result
= var
->u
.fn
.function
;
1317 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1318 int bitsize
, struct value
*newval
)
1324 case INTERNALVAR_VALUE
:
1325 addr
= value_contents_writeable (var
->u
.value
);
1328 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1329 value_as_long (newval
), bitpos
, bitsize
);
1331 memcpy (addr
+ offset
, value_contents (newval
),
1332 TYPE_LENGTH (value_type (newval
)));
1336 /* We can never get a component of any other kind. */
1337 internal_error (__FILE__
, __LINE__
, "set_internalvar_component");
1342 set_internalvar (struct internalvar
*var
, struct value
*val
)
1344 enum internalvar_kind new_kind
;
1345 union internalvar_data new_data
= { 0 };
1347 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1348 error (_("Cannot overwrite convenience function %s"), var
->name
);
1350 /* Prepare new contents. */
1351 switch (TYPE_CODE (check_typedef (value_type (val
))))
1353 case TYPE_CODE_VOID
:
1354 new_kind
= INTERNALVAR_VOID
;
1357 case TYPE_CODE_INTERNAL_FUNCTION
:
1358 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1359 new_kind
= INTERNALVAR_FUNCTION
;
1360 get_internalvar_function (VALUE_INTERNALVAR (val
),
1361 &new_data
.fn
.function
);
1362 /* Copies created here are never canonical. */
1366 new_kind
= INTERNALVAR_INTEGER
;
1367 new_data
.integer
.type
= value_type (val
);
1368 new_data
.integer
.val
= value_as_long (val
);
1372 new_kind
= INTERNALVAR_POINTER
;
1373 new_data
.pointer
.type
= value_type (val
);
1374 new_data
.pointer
.val
= value_as_address (val
);
1378 new_kind
= INTERNALVAR_VALUE
;
1379 new_data
.value
= value_copy (val
);
1380 new_data
.value
->modifiable
= 1;
1382 /* Force the value to be fetched from the target now, to avoid problems
1383 later when this internalvar is referenced and the target is gone or
1385 if (value_lazy (new_data
.value
))
1386 value_fetch_lazy (new_data
.value
);
1388 /* Release the value from the value chain to prevent it from being
1389 deleted by free_all_values. From here on this function should not
1390 call error () until new_data is installed into the var->u to avoid
1392 release_value (new_data
.value
);
1396 /* Clean up old contents. */
1397 clear_internalvar (var
);
1400 var
->kind
= new_kind
;
1402 /* End code which must not call error(). */
1406 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1408 /* Clean up old contents. */
1409 clear_internalvar (var
);
1411 var
->kind
= INTERNALVAR_INTEGER
;
1412 var
->u
.integer
.type
= NULL
;
1413 var
->u
.integer
.val
= l
;
1417 set_internalvar_string (struct internalvar
*var
, const char *string
)
1419 /* Clean up old contents. */
1420 clear_internalvar (var
);
1422 var
->kind
= INTERNALVAR_STRING
;
1423 var
->u
.string
= xstrdup (string
);
1427 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1429 /* Clean up old contents. */
1430 clear_internalvar (var
);
1432 var
->kind
= INTERNALVAR_FUNCTION
;
1433 var
->u
.fn
.function
= f
;
1434 var
->u
.fn
.canonical
= 1;
1435 /* Variables installed here are always the canonical version. */
1439 clear_internalvar (struct internalvar
*var
)
1441 /* Clean up old contents. */
1444 case INTERNALVAR_VALUE
:
1445 value_free (var
->u
.value
);
1448 case INTERNALVAR_STRING
:
1449 xfree (var
->u
.string
);
1456 /* Reset to void kind. */
1457 var
->kind
= INTERNALVAR_VOID
;
1461 internalvar_name (struct internalvar
*var
)
1466 static struct internal_function
*
1467 create_internal_function (const char *name
,
1468 internal_function_fn handler
, void *cookie
)
1470 struct internal_function
*ifn
= XNEW (struct internal_function
);
1472 ifn
->name
= xstrdup (name
);
1473 ifn
->handler
= handler
;
1474 ifn
->cookie
= cookie
;
1479 value_internal_function_name (struct value
*val
)
1481 struct internal_function
*ifn
;
1484 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1485 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1486 gdb_assert (result
);
1492 call_internal_function (struct gdbarch
*gdbarch
,
1493 const struct language_defn
*language
,
1494 struct value
*func
, int argc
, struct value
**argv
)
1496 struct internal_function
*ifn
;
1499 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1500 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1501 gdb_assert (result
);
1503 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1506 /* The 'function' command. This does nothing -- it is just a
1507 placeholder to let "help function NAME" work. This is also used as
1508 the implementation of the sub-command that is created when
1509 registering an internal function. */
1511 function_command (char *command
, int from_tty
)
1516 /* Clean up if an internal function's command is destroyed. */
1518 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1524 /* Add a new internal function. NAME is the name of the function; DOC
1525 is a documentation string describing the function. HANDLER is
1526 called when the function is invoked. COOKIE is an arbitrary
1527 pointer which is passed to HANDLER and is intended for "user
1530 add_internal_function (const char *name
, const char *doc
,
1531 internal_function_fn handler
, void *cookie
)
1533 struct cmd_list_element
*cmd
;
1534 struct internal_function
*ifn
;
1535 struct internalvar
*var
= lookup_internalvar (name
);
1537 ifn
= create_internal_function (name
, handler
, cookie
);
1538 set_internalvar_function (var
, ifn
);
1540 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1542 cmd
->destroyer
= function_destroyer
;
1545 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1546 prevent cycles / duplicates. */
1549 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1550 htab_t copied_types
)
1552 if (TYPE_OBJFILE (value
->type
) == objfile
)
1553 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1555 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1556 value
->enclosing_type
= copy_type_recursive (objfile
,
1557 value
->enclosing_type
,
1561 /* Likewise for internal variable VAR. */
1564 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1565 htab_t copied_types
)
1569 case INTERNALVAR_INTEGER
:
1570 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1572 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1575 case INTERNALVAR_POINTER
:
1576 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1578 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1581 case INTERNALVAR_VALUE
:
1582 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1587 /* Update the internal variables and value history when OBJFILE is
1588 discarded; we must copy the types out of the objfile. New global types
1589 will be created for every convenience variable which currently points to
1590 this objfile's types, and the convenience variables will be adjusted to
1591 use the new global types. */
1594 preserve_values (struct objfile
*objfile
)
1596 htab_t copied_types
;
1597 struct value_history_chunk
*cur
;
1598 struct internalvar
*var
;
1601 /* Create the hash table. We allocate on the objfile's obstack, since
1602 it is soon to be deleted. */
1603 copied_types
= create_copied_types_hash (objfile
);
1605 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1606 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1608 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1610 for (var
= internalvars
; var
; var
= var
->next
)
1611 preserve_one_internalvar (var
, objfile
, copied_types
);
1613 preserve_python_values (objfile
, copied_types
);
1615 htab_delete (copied_types
);
1619 show_convenience (char *ignore
, int from_tty
)
1621 struct gdbarch
*gdbarch
= get_current_arch ();
1622 struct internalvar
*var
;
1624 struct value_print_options opts
;
1626 get_user_print_options (&opts
);
1627 for (var
= internalvars
; var
; var
= var
->next
)
1633 printf_filtered (("$%s = "), var
->name
);
1634 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1636 printf_filtered (("\n"));
1639 printf_unfiltered (_("\
1640 No debugger convenience variables now defined.\n\
1641 Convenience variables have names starting with \"$\";\n\
1642 use \"set\" as in \"set $foo = 5\" to define them.\n"));
1645 /* Extract a value as a C number (either long or double).
1646 Knows how to convert fixed values to double, or
1647 floating values to long.
1648 Does not deallocate the value. */
1651 value_as_long (struct value
*val
)
1653 /* This coerces arrays and functions, which is necessary (e.g.
1654 in disassemble_command). It also dereferences references, which
1655 I suspect is the most logical thing to do. */
1656 val
= coerce_array (val
);
1657 return unpack_long (value_type (val
), value_contents (val
));
1661 value_as_double (struct value
*val
)
1666 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1668 error (_("Invalid floating value found in program."));
1672 /* Extract a value as a C pointer. Does not deallocate the value.
1673 Note that val's type may not actually be a pointer; value_as_long
1674 handles all the cases. */
1676 value_as_address (struct value
*val
)
1678 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1680 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1681 whether we want this to be true eventually. */
1683 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1684 non-address (e.g. argument to "signal", "info break", etc.), or
1685 for pointers to char, in which the low bits *are* significant. */
1686 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1689 /* There are several targets (IA-64, PowerPC, and others) which
1690 don't represent pointers to functions as simply the address of
1691 the function's entry point. For example, on the IA-64, a
1692 function pointer points to a two-word descriptor, generated by
1693 the linker, which contains the function's entry point, and the
1694 value the IA-64 "global pointer" register should have --- to
1695 support position-independent code. The linker generates
1696 descriptors only for those functions whose addresses are taken.
1698 On such targets, it's difficult for GDB to convert an arbitrary
1699 function address into a function pointer; it has to either find
1700 an existing descriptor for that function, or call malloc and
1701 build its own. On some targets, it is impossible for GDB to
1702 build a descriptor at all: the descriptor must contain a jump
1703 instruction; data memory cannot be executed; and code memory
1706 Upon entry to this function, if VAL is a value of type `function'
1707 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1708 value_address (val) is the address of the function. This is what
1709 you'll get if you evaluate an expression like `main'. The call
1710 to COERCE_ARRAY below actually does all the usual unary
1711 conversions, which includes converting values of type `function'
1712 to `pointer to function'. This is the challenging conversion
1713 discussed above. Then, `unpack_long' will convert that pointer
1714 back into an address.
1716 So, suppose the user types `disassemble foo' on an architecture
1717 with a strange function pointer representation, on which GDB
1718 cannot build its own descriptors, and suppose further that `foo'
1719 has no linker-built descriptor. The address->pointer conversion
1720 will signal an error and prevent the command from running, even
1721 though the next step would have been to convert the pointer
1722 directly back into the same address.
1724 The following shortcut avoids this whole mess. If VAL is a
1725 function, just return its address directly. */
1726 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1727 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1728 return value_address (val
);
1730 val
= coerce_array (val
);
1732 /* Some architectures (e.g. Harvard), map instruction and data
1733 addresses onto a single large unified address space. For
1734 instance: An architecture may consider a large integer in the
1735 range 0x10000000 .. 0x1000ffff to already represent a data
1736 addresses (hence not need a pointer to address conversion) while
1737 a small integer would still need to be converted integer to
1738 pointer to address. Just assume such architectures handle all
1739 integer conversions in a single function. */
1743 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1744 must admonish GDB hackers to make sure its behavior matches the
1745 compiler's, whenever possible.
1747 In general, I think GDB should evaluate expressions the same way
1748 the compiler does. When the user copies an expression out of
1749 their source code and hands it to a `print' command, they should
1750 get the same value the compiler would have computed. Any
1751 deviation from this rule can cause major confusion and annoyance,
1752 and needs to be justified carefully. In other words, GDB doesn't
1753 really have the freedom to do these conversions in clever and
1756 AndrewC pointed out that users aren't complaining about how GDB
1757 casts integers to pointers; they are complaining that they can't
1758 take an address from a disassembly listing and give it to `x/i'.
1759 This is certainly important.
1761 Adding an architecture method like integer_to_address() certainly
1762 makes it possible for GDB to "get it right" in all circumstances
1763 --- the target has complete control over how things get done, so
1764 people can Do The Right Thing for their target without breaking
1765 anyone else. The standard doesn't specify how integers get
1766 converted to pointers; usually, the ABI doesn't either, but
1767 ABI-specific code is a more reasonable place to handle it. */
1769 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1770 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1771 && gdbarch_integer_to_address_p (gdbarch
))
1772 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1773 value_contents (val
));
1775 return unpack_long (value_type (val
), value_contents (val
));
1779 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1780 as a long, or as a double, assuming the raw data is described
1781 by type TYPE. Knows how to convert different sizes of values
1782 and can convert between fixed and floating point. We don't assume
1783 any alignment for the raw data. Return value is in host byte order.
1785 If you want functions and arrays to be coerced to pointers, and
1786 references to be dereferenced, call value_as_long() instead.
1788 C++: It is assumed that the front-end has taken care of
1789 all matters concerning pointers to members. A pointer
1790 to member which reaches here is considered to be equivalent
1791 to an INT (or some size). After all, it is only an offset. */
1794 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1796 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1797 enum type_code code
= TYPE_CODE (type
);
1798 int len
= TYPE_LENGTH (type
);
1799 int nosign
= TYPE_UNSIGNED (type
);
1803 case TYPE_CODE_TYPEDEF
:
1804 return unpack_long (check_typedef (type
), valaddr
);
1805 case TYPE_CODE_ENUM
:
1806 case TYPE_CODE_FLAGS
:
1807 case TYPE_CODE_BOOL
:
1809 case TYPE_CODE_CHAR
:
1810 case TYPE_CODE_RANGE
:
1811 case TYPE_CODE_MEMBERPTR
:
1813 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1815 return extract_signed_integer (valaddr
, len
, byte_order
);
1818 return extract_typed_floating (valaddr
, type
);
1820 case TYPE_CODE_DECFLOAT
:
1821 /* libdecnumber has a function to convert from decimal to integer, but
1822 it doesn't work when the decimal number has a fractional part. */
1823 return decimal_to_doublest (valaddr
, len
, byte_order
);
1827 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1828 whether we want this to be true eventually. */
1829 return extract_typed_address (valaddr
, type
);
1832 error (_("Value can't be converted to integer."));
1834 return 0; /* Placate lint. */
1837 /* Return a double value from the specified type and address.
1838 INVP points to an int which is set to 0 for valid value,
1839 1 for invalid value (bad float format). In either case,
1840 the returned double is OK to use. Argument is in target
1841 format, result is in host format. */
1844 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1846 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1847 enum type_code code
;
1851 *invp
= 0; /* Assume valid. */
1852 CHECK_TYPEDEF (type
);
1853 code
= TYPE_CODE (type
);
1854 len
= TYPE_LENGTH (type
);
1855 nosign
= TYPE_UNSIGNED (type
);
1856 if (code
== TYPE_CODE_FLT
)
1858 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1859 floating-point value was valid (using the macro
1860 INVALID_FLOAT). That test/macro have been removed.
1862 It turns out that only the VAX defined this macro and then
1863 only in a non-portable way. Fixing the portability problem
1864 wouldn't help since the VAX floating-point code is also badly
1865 bit-rotten. The target needs to add definitions for the
1866 methods gdbarch_float_format and gdbarch_double_format - these
1867 exactly describe the target floating-point format. The
1868 problem here is that the corresponding floatformat_vax_f and
1869 floatformat_vax_d values these methods should be set to are
1870 also not defined either. Oops!
1872 Hopefully someone will add both the missing floatformat
1873 definitions and the new cases for floatformat_is_valid (). */
1875 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1881 return extract_typed_floating (valaddr
, type
);
1883 else if (code
== TYPE_CODE_DECFLOAT
)
1884 return decimal_to_doublest (valaddr
, len
, byte_order
);
1887 /* Unsigned -- be sure we compensate for signed LONGEST. */
1888 return (ULONGEST
) unpack_long (type
, valaddr
);
1892 /* Signed -- we are OK with unpack_long. */
1893 return unpack_long (type
, valaddr
);
1897 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1898 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1899 We don't assume any alignment for the raw data. Return value is in
1902 If you want functions and arrays to be coerced to pointers, and
1903 references to be dereferenced, call value_as_address() instead.
1905 C++: It is assumed that the front-end has taken care of
1906 all matters concerning pointers to members. A pointer
1907 to member which reaches here is considered to be equivalent
1908 to an INT (or some size). After all, it is only an offset. */
1911 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1913 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1914 whether we want this to be true eventually. */
1915 return unpack_long (type
, valaddr
);
1919 /* Get the value of the FIELDNO'th field (which must be static) of
1920 TYPE. Return NULL if the field doesn't exist or has been
1924 value_static_field (struct type
*type
, int fieldno
)
1926 struct value
*retval
;
1928 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
1930 case FIELD_LOC_KIND_PHYSADDR
:
1931 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1932 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1934 case FIELD_LOC_KIND_PHYSNAME
:
1936 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1937 /*TYPE_FIELD_NAME (type, fieldno);*/
1938 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1942 /* With some compilers, e.g. HP aCC, static data members are
1943 reported as non-debuggable symbols */
1944 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1951 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1952 SYMBOL_VALUE_ADDRESS (msym
));
1956 retval
= value_of_variable (sym
, NULL
);
1960 gdb_assert_not_reached ("unexpected field location kind");
1966 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1967 You have to be careful here, since the size of the data area for the value
1968 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1969 than the old enclosing type, you have to allocate more space for the
1973 set_value_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1975 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1977 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1979 val
->enclosing_type
= new_encl_type
;
1982 /* Given a value ARG1 (offset by OFFSET bytes)
1983 of a struct or union type ARG_TYPE,
1984 extract and return the value of one of its (non-static) fields.
1985 FIELDNO says which field. */
1988 value_primitive_field (struct value
*arg1
, int offset
,
1989 int fieldno
, struct type
*arg_type
)
1994 CHECK_TYPEDEF (arg_type
);
1995 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
1997 /* Call check_typedef on our type to make sure that, if TYPE
1998 is a TYPE_CODE_TYPEDEF, its length is set to the length
1999 of the target type instead of zero. However, we do not
2000 replace the typedef type by the target type, because we want
2001 to keep the typedef in order to be able to print the type
2002 description correctly. */
2003 check_typedef (type
);
2005 /* Handle packed fields */
2007 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
2009 /* Create a new value for the bitfield, with bitpos and bitsize
2010 set. If possible, arrange offset and bitpos so that we can
2011 do a single aligned read of the size of the containing type.
2012 Otherwise, adjust offset to the byte containing the first
2013 bit. Assume that the address, offset, and embedded offset
2014 are sufficiently aligned. */
2015 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
2016 int container_bitsize
= TYPE_LENGTH (type
) * 8;
2018 v
= allocate_value_lazy (type
);
2019 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
2020 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
2021 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
2022 v
->bitpos
= bitpos
% container_bitsize
;
2024 v
->bitpos
= bitpos
% 8;
2025 v
->offset
= (value_embedded_offset (arg1
)
2027 + (bitpos
- v
->bitpos
) / 8);
2029 value_incref (v
->parent
);
2030 if (!value_lazy (arg1
))
2031 value_fetch_lazy (v
);
2033 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
2035 /* This field is actually a base subobject, so preserve the
2036 entire object's contents for later references to virtual
2039 /* Lazy register values with offsets are not supported. */
2040 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2041 value_fetch_lazy (arg1
);
2043 if (value_lazy (arg1
))
2044 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2047 v
= allocate_value (value_enclosing_type (arg1
));
2048 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2049 TYPE_LENGTH (value_enclosing_type (arg1
)));
2052 v
->offset
= value_offset (arg1
);
2053 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2054 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2058 /* Plain old data member */
2059 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2061 /* Lazy register values with offsets are not supported. */
2062 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2063 value_fetch_lazy (arg1
);
2065 if (value_lazy (arg1
))
2066 v
= allocate_value_lazy (type
);
2069 v
= allocate_value (type
);
2070 memcpy (value_contents_raw (v
),
2071 value_contents_raw (arg1
) + offset
,
2072 TYPE_LENGTH (type
));
2074 v
->offset
= (value_offset (arg1
) + offset
2075 + value_embedded_offset (arg1
));
2077 set_value_component_location (v
, arg1
);
2078 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2079 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2083 /* Given a value ARG1 of a struct or union type,
2084 extract and return the value of one of its (non-static) fields.
2085 FIELDNO says which field. */
2088 value_field (struct value
*arg1
, int fieldno
)
2090 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2093 /* Return a non-virtual function as a value.
2094 F is the list of member functions which contains the desired method.
2095 J is an index into F which provides the desired method.
2097 We only use the symbol for its address, so be happy with either a
2098 full symbol or a minimal symbol.
2102 value_fn_field (struct value
**arg1p
, struct fn_field
*f
, int j
, struct type
*type
,
2106 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2107 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2109 struct minimal_symbol
*msym
;
2111 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2118 gdb_assert (sym
== NULL
);
2119 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2124 v
= allocate_value (ftype
);
2127 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2131 /* The minimal symbol might point to a function descriptor;
2132 resolve it to the actual code address instead. */
2133 struct objfile
*objfile
= msymbol_objfile (msym
);
2134 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2136 set_value_address (v
,
2137 gdbarch_convert_from_func_ptr_addr
2138 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2143 if (type
!= value_type (*arg1p
))
2144 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2145 value_addr (*arg1p
)));
2147 /* Move the `this' pointer according to the offset.
2148 VALUE_OFFSET (*arg1p) += offset;
2156 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2157 object at VALADDR. The bitfield starts at BITPOS bits and contains
2160 Extracting bits depends on endianness of the machine. Compute the
2161 number of least significant bits to discard. For big endian machines,
2162 we compute the total number of bits in the anonymous object, subtract
2163 off the bit count from the MSB of the object to the MSB of the
2164 bitfield, then the size of the bitfield, which leaves the LSB discard
2165 count. For little endian machines, the discard count is simply the
2166 number of bits from the LSB of the anonymous object to the LSB of the
2169 If the field is signed, we also do sign extension. */
2172 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2173 int bitpos
, int bitsize
)
2175 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2181 /* Read the minimum number of bytes required; there may not be
2182 enough bytes to read an entire ULONGEST. */
2183 CHECK_TYPEDEF (field_type
);
2185 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2187 bytes_read
= TYPE_LENGTH (field_type
);
2189 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2190 bytes_read
, byte_order
);
2192 /* Extract bits. See comment above. */
2194 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2195 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2197 lsbcount
= (bitpos
% 8);
2200 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2201 If the field is signed, and is negative, then sign extend. */
2203 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2205 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2207 if (!TYPE_UNSIGNED (field_type
))
2209 if (val
& (valmask
^ (valmask
>> 1)))
2218 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2219 VALADDR. See unpack_bits_as_long for more details. */
2222 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2224 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2225 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2226 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2228 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2231 /* Modify the value of a bitfield. ADDR points to a block of memory in
2232 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2233 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2234 indicate which bits (in target bit order) comprise the bitfield.
2235 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
2236 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2239 modify_field (struct type
*type
, gdb_byte
*addr
,
2240 LONGEST fieldval
, int bitpos
, int bitsize
)
2242 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2244 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2247 /* Normalize BITPOS. */
2251 /* If a negative fieldval fits in the field in question, chop
2252 off the sign extension bits. */
2253 if ((~fieldval
& ~(mask
>> 1)) == 0)
2256 /* Warn if value is too big to fit in the field in question. */
2257 if (0 != (fieldval
& ~mask
))
2259 /* FIXME: would like to include fieldval in the message, but
2260 we don't have a sprintf_longest. */
2261 warning (_("Value does not fit in %d bits."), bitsize
);
2263 /* Truncate it, otherwise adjoining fields may be corrupted. */
2267 /* Ensure no bytes outside of the modified ones get accessed as it may cause
2268 false valgrind reports. */
2270 bytesize
= (bitpos
+ bitsize
+ 7) / 8;
2271 oword
= extract_unsigned_integer (addr
, bytesize
, byte_order
);
2273 /* Shifting for bit field depends on endianness of the target machine. */
2274 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2275 bitpos
= bytesize
* 8 - bitpos
- bitsize
;
2277 oword
&= ~(mask
<< bitpos
);
2278 oword
|= fieldval
<< bitpos
;
2280 store_unsigned_integer (addr
, bytesize
, byte_order
, oword
);
2283 /* Pack NUM into BUF using a target format of TYPE. */
2286 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2288 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2291 type
= check_typedef (type
);
2292 len
= TYPE_LENGTH (type
);
2294 switch (TYPE_CODE (type
))
2297 case TYPE_CODE_CHAR
:
2298 case TYPE_CODE_ENUM
:
2299 case TYPE_CODE_FLAGS
:
2300 case TYPE_CODE_BOOL
:
2301 case TYPE_CODE_RANGE
:
2302 case TYPE_CODE_MEMBERPTR
:
2303 store_signed_integer (buf
, len
, byte_order
, num
);
2308 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2312 error (_("Unexpected type (%d) encountered for integer constant."),
2318 /* Pack NUM into BUF using a target format of TYPE. */
2321 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2324 enum bfd_endian byte_order
;
2326 type
= check_typedef (type
);
2327 len
= TYPE_LENGTH (type
);
2328 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2330 switch (TYPE_CODE (type
))
2333 case TYPE_CODE_CHAR
:
2334 case TYPE_CODE_ENUM
:
2335 case TYPE_CODE_FLAGS
:
2336 case TYPE_CODE_BOOL
:
2337 case TYPE_CODE_RANGE
:
2338 case TYPE_CODE_MEMBERPTR
:
2339 store_unsigned_integer (buf
, len
, byte_order
, num
);
2344 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2349 Unexpected type (%d) encountered for unsigned integer constant."),
2355 /* Convert C numbers into newly allocated values. */
2358 value_from_longest (struct type
*type
, LONGEST num
)
2360 struct value
*val
= allocate_value (type
);
2362 pack_long (value_contents_raw (val
), type
, num
);
2367 /* Convert C unsigned numbers into newly allocated values. */
2370 value_from_ulongest (struct type
*type
, ULONGEST num
)
2372 struct value
*val
= allocate_value (type
);
2374 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2380 /* Create a value representing a pointer of type TYPE to the address
2383 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2385 struct value
*val
= allocate_value (type
);
2387 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2392 /* Create a value of type TYPE whose contents come from VALADDR, if it
2393 is non-null, and whose memory address (in the inferior) is
2397 value_from_contents_and_address (struct type
*type
,
2398 const gdb_byte
*valaddr
,
2401 struct value
*v
= allocate_value (type
);
2403 if (valaddr
== NULL
)
2404 set_value_lazy (v
, 1);
2406 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2407 set_value_address (v
, address
);
2408 VALUE_LVAL (v
) = lval_memory
;
2413 value_from_double (struct type
*type
, DOUBLEST num
)
2415 struct value
*val
= allocate_value (type
);
2416 struct type
*base_type
= check_typedef (type
);
2417 enum type_code code
= TYPE_CODE (base_type
);
2419 if (code
== TYPE_CODE_FLT
)
2421 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2424 error (_("Unexpected type encountered for floating constant."));
2430 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2432 struct value
*val
= allocate_value (type
);
2434 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2439 coerce_ref (struct value
*arg
)
2441 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2443 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2444 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2445 unpack_pointer (value_type (arg
),
2446 value_contents (arg
)));
2451 coerce_array (struct value
*arg
)
2455 arg
= coerce_ref (arg
);
2456 type
= check_typedef (value_type (arg
));
2458 switch (TYPE_CODE (type
))
2460 case TYPE_CODE_ARRAY
:
2461 if (!TYPE_VECTOR (type
) && current_language
->c_style_arrays
)
2462 arg
= value_coerce_array (arg
);
2464 case TYPE_CODE_FUNC
:
2465 arg
= value_coerce_function (arg
);
2472 /* Return true if the function returning the specified type is using
2473 the convention of returning structures in memory (passing in the
2474 address as a hidden first parameter). */
2477 using_struct_return (struct gdbarch
*gdbarch
,
2478 struct type
*func_type
, struct type
*value_type
)
2480 enum type_code code
= TYPE_CODE (value_type
);
2482 if (code
== TYPE_CODE_ERROR
)
2483 error (_("Function return type unknown."));
2485 if (code
== TYPE_CODE_VOID
)
2486 /* A void return value is never in memory. See also corresponding
2487 code in "print_return_value". */
2490 /* Probe the architecture for the return-value convention. */
2491 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2493 != RETURN_VALUE_REGISTER_CONVENTION
);
2496 /* Set the initialized field in a value struct. */
2499 set_value_initialized (struct value
*val
, int status
)
2501 val
->initialized
= status
;
2504 /* Return the initialized field in a value struct. */
2507 value_initialized (struct value
*val
)
2509 return val
->initialized
;
2513 _initialize_values (void)
2515 add_cmd ("convenience", no_class
, show_convenience
, _("\
2516 Debugger convenience (\"$foo\") variables.\n\
2517 These variables are created when you assign them values;\n\
2518 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2520 A few convenience variables are given values automatically:\n\
2521 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2522 \"$__\" holds the contents of the last address examined with \"x\"."),
2525 add_cmd ("values", no_class
, show_values
,
2526 _("Elements of value history around item number IDX (or last ten)."),
2529 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2530 Initialize a convenience variable if necessary.\n\
2531 init-if-undefined VARIABLE = EXPRESSION\n\
2532 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2533 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2534 VARIABLE is already initialized."));
2536 add_prefix_cmd ("function", no_class
, function_command
, _("\
2537 Placeholder command for showing help on convenience functions."),
2538 &functionlist
, "function ", 0, &cmdlist
);