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_lazy (type
);
337 VALUE_LVAL (v
) = lval_computed
;
338 v
->location
.computed
.funcs
= funcs
;
339 v
->location
.computed
.closure
= closure
;
344 /* Accessor methods. */
347 value_next (struct value
*value
)
353 value_type (const struct value
*value
)
358 deprecated_set_value_type (struct value
*value
, struct type
*type
)
364 value_offset (const struct value
*value
)
366 return value
->offset
;
369 set_value_offset (struct value
*value
, int offset
)
371 value
->offset
= offset
;
375 value_bitpos (const struct value
*value
)
377 return value
->bitpos
;
380 set_value_bitpos (struct value
*value
, int bit
)
386 value_bitsize (const struct value
*value
)
388 return value
->bitsize
;
391 set_value_bitsize (struct value
*value
, int bit
)
393 value
->bitsize
= bit
;
397 value_parent (struct value
*value
)
399 return value
->parent
;
403 value_contents_raw (struct value
*value
)
405 allocate_value_contents (value
);
406 return value
->contents
+ value
->embedded_offset
;
410 value_contents_all_raw (struct value
*value
)
412 allocate_value_contents (value
);
413 return value
->contents
;
417 value_enclosing_type (struct value
*value
)
419 return value
->enclosing_type
;
423 require_not_optimized_out (struct value
*value
)
425 if (value
->optimized_out
)
426 error (_("value has been optimized out"));
430 value_contents_for_printing (struct value
*value
)
433 value_fetch_lazy (value
);
434 return value
->contents
;
438 value_contents_for_printing_const (const struct value
*value
)
440 gdb_assert (!value
->lazy
);
441 return value
->contents
;
445 value_contents_all (struct value
*value
)
447 const gdb_byte
*result
= value_contents_for_printing (value
);
448 require_not_optimized_out (value
);
453 value_lazy (struct value
*value
)
459 set_value_lazy (struct value
*value
, int val
)
465 value_stack (struct value
*value
)
471 set_value_stack (struct value
*value
, int val
)
477 value_contents (struct value
*value
)
479 const gdb_byte
*result
= value_contents_writeable (value
);
480 require_not_optimized_out (value
);
485 value_contents_writeable (struct value
*value
)
488 value_fetch_lazy (value
);
489 return value_contents_raw (value
);
492 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
493 this function is different from value_equal; in C the operator ==
494 can return 0 even if the two values being compared are equal. */
497 value_contents_equal (struct value
*val1
, struct value
*val2
)
503 type1
= check_typedef (value_type (val1
));
504 type2
= check_typedef (value_type (val2
));
505 len
= TYPE_LENGTH (type1
);
506 if (len
!= TYPE_LENGTH (type2
))
509 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
513 value_optimized_out (struct value
*value
)
515 return value
->optimized_out
;
519 set_value_optimized_out (struct value
*value
, int val
)
521 value
->optimized_out
= val
;
525 value_entirely_optimized_out (const struct value
*value
)
527 if (!value
->optimized_out
)
529 if (value
->lval
!= lval_computed
530 || !value
->location
.computed
.funcs
->check_any_valid
)
532 return !value
->location
.computed
.funcs
->check_any_valid (value
);
536 value_bits_valid (const struct value
*value
, int offset
, int length
)
538 if (value
== NULL
|| !value
->optimized_out
)
540 if (value
->lval
!= lval_computed
541 || !value
->location
.computed
.funcs
->check_validity
)
543 return value
->location
.computed
.funcs
->check_validity (value
, offset
,
548 value_bits_synthetic_pointer (const struct value
*value
,
549 int offset
, int length
)
551 if (value
== NULL
|| value
->lval
!= lval_computed
552 || !value
->location
.computed
.funcs
->check_synthetic_pointer
)
554 return value
->location
.computed
.funcs
->check_synthetic_pointer (value
,
560 value_embedded_offset (struct value
*value
)
562 return value
->embedded_offset
;
566 set_value_embedded_offset (struct value
*value
, int val
)
568 value
->embedded_offset
= val
;
572 value_pointed_to_offset (struct value
*value
)
574 return value
->pointed_to_offset
;
578 set_value_pointed_to_offset (struct value
*value
, int val
)
580 value
->pointed_to_offset
= val
;
584 value_computed_funcs (struct value
*v
)
586 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
588 return v
->location
.computed
.funcs
;
592 value_computed_closure (const struct value
*v
)
594 gdb_assert (v
->lval
== lval_computed
);
596 return v
->location
.computed
.closure
;
600 deprecated_value_lval_hack (struct value
*value
)
606 value_address (const struct value
*value
)
608 if (value
->lval
== lval_internalvar
609 || value
->lval
== lval_internalvar_component
)
611 return value
->location
.address
+ value
->offset
;
615 value_raw_address (struct value
*value
)
617 if (value
->lval
== lval_internalvar
618 || value
->lval
== lval_internalvar_component
)
620 return value
->location
.address
;
624 set_value_address (struct value
*value
, CORE_ADDR addr
)
626 gdb_assert (value
->lval
!= lval_internalvar
627 && value
->lval
!= lval_internalvar_component
);
628 value
->location
.address
= addr
;
631 struct internalvar
**
632 deprecated_value_internalvar_hack (struct value
*value
)
634 return &value
->location
.internalvar
;
638 deprecated_value_frame_id_hack (struct value
*value
)
640 return &value
->frame_id
;
644 deprecated_value_regnum_hack (struct value
*value
)
646 return &value
->regnum
;
650 deprecated_value_modifiable (struct value
*value
)
652 return value
->modifiable
;
655 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
657 value
->modifiable
= modifiable
;
660 /* Return a mark in the value chain. All values allocated after the
661 mark is obtained (except for those released) are subject to being freed
662 if a subsequent value_free_to_mark is passed the mark. */
669 /* Take a reference to VAL. VAL will not be deallocated until all
670 references are released. */
673 value_incref (struct value
*val
)
675 val
->reference_count
++;
678 /* Release a reference to VAL, which was acquired with value_incref.
679 This function is also called to deallocate values from the value
683 value_free (struct value
*val
)
687 gdb_assert (val
->reference_count
> 0);
688 val
->reference_count
--;
689 if (val
->reference_count
> 0)
692 /* If there's an associated parent value, drop our reference to
694 if (val
->parent
!= NULL
)
695 value_free (val
->parent
);
697 if (VALUE_LVAL (val
) == lval_computed
)
699 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
701 if (funcs
->free_closure
)
702 funcs
->free_closure (val
);
705 xfree (val
->contents
);
710 /* Free all values allocated since MARK was obtained by value_mark
711 (except for those released). */
713 value_free_to_mark (struct value
*mark
)
718 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
726 /* Free all the values that have been allocated (except for those released).
727 Call after each command, successful or not.
728 In practice this is called before each command, which is sufficient. */
731 free_all_values (void)
736 for (val
= all_values
; val
; val
= next
)
745 /* Frees all the elements in a chain of values. */
748 free_value_chain (struct value
*v
)
754 next
= value_next (v
);
759 /* Remove VAL from the chain all_values
760 so it will not be freed automatically. */
763 release_value (struct value
*val
)
767 if (all_values
== val
)
769 all_values
= val
->next
;
774 for (v
= all_values
; v
; v
= v
->next
)
785 /* Release all values up to mark */
787 value_release_to_mark (struct value
*mark
)
792 for (val
= next
= all_values
; next
; next
= next
->next
)
793 if (next
->next
== mark
)
795 all_values
= next
->next
;
803 /* Return a copy of the value ARG.
804 It contains the same contents, for same memory address,
805 but it's a different block of storage. */
808 value_copy (struct value
*arg
)
810 struct type
*encl_type
= value_enclosing_type (arg
);
813 if (value_lazy (arg
))
814 val
= allocate_value_lazy (encl_type
);
816 val
= allocate_value (encl_type
);
817 val
->type
= arg
->type
;
818 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
819 val
->location
= arg
->location
;
820 val
->offset
= arg
->offset
;
821 val
->bitpos
= arg
->bitpos
;
822 val
->bitsize
= arg
->bitsize
;
823 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
824 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
825 val
->lazy
= arg
->lazy
;
826 val
->optimized_out
= arg
->optimized_out
;
827 val
->embedded_offset
= value_embedded_offset (arg
);
828 val
->pointed_to_offset
= arg
->pointed_to_offset
;
829 val
->modifiable
= arg
->modifiable
;
830 if (!value_lazy (val
))
832 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
833 TYPE_LENGTH (value_enclosing_type (arg
)));
836 val
->parent
= arg
->parent
;
838 value_incref (val
->parent
);
839 if (VALUE_LVAL (val
) == lval_computed
)
841 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
843 if (funcs
->copy_closure
)
844 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
849 /* Return a version of ARG that is non-lvalue. */
852 value_non_lval (struct value
*arg
)
854 if (VALUE_LVAL (arg
) != not_lval
)
856 struct type
*enc_type
= value_enclosing_type (arg
);
857 struct value
*val
= allocate_value (enc_type
);
859 memcpy (value_contents_all_raw (val
), value_contents_all (arg
),
860 TYPE_LENGTH (enc_type
));
861 val
->type
= arg
->type
;
862 set_value_embedded_offset (val
, value_embedded_offset (arg
));
863 set_value_pointed_to_offset (val
, value_pointed_to_offset (arg
));
870 set_value_component_location (struct value
*component
,
871 const struct value
*whole
)
873 if (whole
->lval
== lval_internalvar
)
874 VALUE_LVAL (component
) = lval_internalvar_component
;
876 VALUE_LVAL (component
) = whole
->lval
;
878 component
->location
= whole
->location
;
879 if (whole
->lval
== lval_computed
)
881 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
883 if (funcs
->copy_closure
)
884 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
889 /* Access to the value history. */
891 /* Record a new value in the value history.
892 Returns the absolute history index of the entry.
893 Result of -1 indicates the value was not saved; otherwise it is the
894 value history index of this new item. */
897 record_latest_value (struct value
*val
)
901 /* We don't want this value to have anything to do with the inferior anymore.
902 In particular, "set $1 = 50" should not affect the variable from which
903 the value was taken, and fast watchpoints should be able to assume that
904 a value on the value history never changes. */
905 if (value_lazy (val
))
906 value_fetch_lazy (val
);
907 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
908 from. This is a bit dubious, because then *&$1 does not just return $1
909 but the current contents of that location. c'est la vie... */
913 /* Here we treat value_history_count as origin-zero
914 and applying to the value being stored now. */
916 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
919 struct value_history_chunk
*new
920 = (struct value_history_chunk
*)
922 xmalloc (sizeof (struct value_history_chunk
));
923 memset (new->values
, 0, sizeof new->values
);
924 new->next
= value_history_chain
;
925 value_history_chain
= new;
928 value_history_chain
->values
[i
] = val
;
930 /* Now we regard value_history_count as origin-one
931 and applying to the value just stored. */
933 return ++value_history_count
;
936 /* Return a copy of the value in the history with sequence number NUM. */
939 access_value_history (int num
)
941 struct value_history_chunk
*chunk
;
946 absnum
+= value_history_count
;
951 error (_("The history is empty."));
953 error (_("There is only one value in the history."));
955 error (_("History does not go back to $$%d."), -num
);
957 if (absnum
> value_history_count
)
958 error (_("History has not yet reached $%d."), absnum
);
962 /* Now absnum is always absolute and origin zero. */
964 chunk
= value_history_chain
;
965 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
966 - absnum
/ VALUE_HISTORY_CHUNK
;
970 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
974 show_values (char *num_exp
, int from_tty
)
982 /* "show values +" should print from the stored position.
983 "show values <exp>" should print around value number <exp>. */
984 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
985 num
= parse_and_eval_long (num_exp
) - 5;
989 /* "show values" means print the last 10 values. */
990 num
= value_history_count
- 9;
996 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
998 struct value_print_options opts
;
1000 val
= access_value_history (i
);
1001 printf_filtered (("$%d = "), i
);
1002 get_user_print_options (&opts
);
1003 value_print (val
, gdb_stdout
, &opts
);
1004 printf_filtered (("\n"));
1007 /* The next "show values +" should start after what we just printed. */
1010 /* Hitting just return after this command should do the same thing as
1011 "show values +". If num_exp is null, this is unnecessary, since
1012 "show values +" is not useful after "show values". */
1013 if (from_tty
&& num_exp
)
1020 /* Internal variables. These are variables within the debugger
1021 that hold values assigned by debugger commands.
1022 The user refers to them with a '$' prefix
1023 that does not appear in the variable names stored internally. */
1027 struct internalvar
*next
;
1030 /* We support various different kinds of content of an internal variable.
1031 enum internalvar_kind specifies the kind, and union internalvar_data
1032 provides the data associated with this particular kind. */
1034 enum internalvar_kind
1036 /* The internal variable is empty. */
1039 /* The value of the internal variable is provided directly as
1040 a GDB value object. */
1043 /* A fresh value is computed via a call-back routine on every
1044 access to the internal variable. */
1045 INTERNALVAR_MAKE_VALUE
,
1047 /* The internal variable holds a GDB internal convenience function. */
1048 INTERNALVAR_FUNCTION
,
1050 /* The variable holds an integer value. */
1051 INTERNALVAR_INTEGER
,
1053 /* The variable holds a pointer value. */
1054 INTERNALVAR_POINTER
,
1056 /* The variable holds a GDB-provided string. */
1061 union internalvar_data
1063 /* A value object used with INTERNALVAR_VALUE. */
1064 struct value
*value
;
1066 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1067 internalvar_make_value make_value
;
1069 /* The internal function used with INTERNALVAR_FUNCTION. */
1072 struct internal_function
*function
;
1073 /* True if this is the canonical name for the function. */
1077 /* An integer value used with INTERNALVAR_INTEGER. */
1080 /* If type is non-NULL, it will be used as the type to generate
1081 a value for this internal variable. If type is NULL, a default
1082 integer type for the architecture is used. */
1087 /* A pointer value used with INTERNALVAR_POINTER. */
1094 /* A string value used with INTERNALVAR_STRING. */
1099 static struct internalvar
*internalvars
;
1101 /* If the variable does not already exist create it and give it the
1102 value given. If no value is given then the default is zero. */
1104 init_if_undefined_command (char* args
, int from_tty
)
1106 struct internalvar
* intvar
;
1108 /* Parse the expression - this is taken from set_command(). */
1109 struct expression
*expr
= parse_expression (args
);
1110 register struct cleanup
*old_chain
=
1111 make_cleanup (free_current_contents
, &expr
);
1113 /* Validate the expression.
1114 Was the expression an assignment?
1115 Or even an expression at all? */
1116 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1117 error (_("Init-if-undefined requires an assignment expression."));
1119 /* Extract the variable from the parsed expression.
1120 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1121 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1122 error (_("The first parameter to init-if-undefined "
1123 "should be a GDB variable."));
1124 intvar
= expr
->elts
[2].internalvar
;
1126 /* Only evaluate the expression if the lvalue is void.
1127 This may still fail if the expresssion is invalid. */
1128 if (intvar
->kind
== INTERNALVAR_VOID
)
1129 evaluate_expression (expr
);
1131 do_cleanups (old_chain
);
1135 /* Look up an internal variable with name NAME. NAME should not
1136 normally include a dollar sign.
1138 If the specified internal variable does not exist,
1139 the return value is NULL. */
1141 struct internalvar
*
1142 lookup_only_internalvar (const char *name
)
1144 struct internalvar
*var
;
1146 for (var
= internalvars
; var
; var
= var
->next
)
1147 if (strcmp (var
->name
, name
) == 0)
1154 /* Create an internal variable with name NAME and with a void value.
1155 NAME should not normally include a dollar sign. */
1157 struct internalvar
*
1158 create_internalvar (const char *name
)
1160 struct internalvar
*var
;
1162 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1163 var
->name
= concat (name
, (char *)NULL
);
1164 var
->kind
= INTERNALVAR_VOID
;
1165 var
->next
= internalvars
;
1170 /* Create an internal variable with name NAME and register FUN as the
1171 function that value_of_internalvar uses to create a value whenever
1172 this variable is referenced. NAME should not normally include a
1175 struct internalvar
*
1176 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1178 struct internalvar
*var
= create_internalvar (name
);
1180 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1181 var
->u
.make_value
= fun
;
1185 /* Look up an internal variable with name NAME. NAME should not
1186 normally include a dollar sign.
1188 If the specified internal variable does not exist,
1189 one is created, with a void value. */
1191 struct internalvar
*
1192 lookup_internalvar (const char *name
)
1194 struct internalvar
*var
;
1196 var
= lookup_only_internalvar (name
);
1200 return create_internalvar (name
);
1203 /* Return current value of internal variable VAR. For variables that
1204 are not inherently typed, use a value type appropriate for GDBARCH. */
1207 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1210 struct trace_state_variable
*tsv
;
1212 /* If there is a trace state variable of the same name, assume that
1213 is what we really want to see. */
1214 tsv
= find_trace_state_variable (var
->name
);
1217 tsv
->value_known
= target_get_trace_state_variable_value (tsv
->number
,
1219 if (tsv
->value_known
)
1220 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int64
,
1223 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1229 case INTERNALVAR_VOID
:
1230 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1233 case INTERNALVAR_FUNCTION
:
1234 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1237 case INTERNALVAR_INTEGER
:
1238 if (!var
->u
.integer
.type
)
1239 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1240 var
->u
.integer
.val
);
1242 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1245 case INTERNALVAR_POINTER
:
1246 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1249 case INTERNALVAR_STRING
:
1250 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1251 builtin_type (gdbarch
)->builtin_char
);
1254 case INTERNALVAR_VALUE
:
1255 val
= value_copy (var
->u
.value
);
1256 if (value_lazy (val
))
1257 value_fetch_lazy (val
);
1260 case INTERNALVAR_MAKE_VALUE
:
1261 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1265 internal_error (__FILE__
, __LINE__
, _("bad kind"));
1268 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1269 on this value go back to affect the original internal variable.
1271 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1272 no underlying modifyable state in the internal variable.
1274 Likewise, if the variable's value is a computed lvalue, we want
1275 references to it to produce another computed lvalue, where
1276 references and assignments actually operate through the
1277 computed value's functions.
1279 This means that internal variables with computed values
1280 behave a little differently from other internal variables:
1281 assignments to them don't just replace the previous value
1282 altogether. At the moment, this seems like the behavior we
1285 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1286 && val
->lval
!= lval_computed
)
1288 VALUE_LVAL (val
) = lval_internalvar
;
1289 VALUE_INTERNALVAR (val
) = var
;
1296 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1300 case INTERNALVAR_INTEGER
:
1301 *result
= var
->u
.integer
.val
;
1310 get_internalvar_function (struct internalvar
*var
,
1311 struct internal_function
**result
)
1315 case INTERNALVAR_FUNCTION
:
1316 *result
= var
->u
.fn
.function
;
1325 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1326 int bitsize
, struct value
*newval
)
1332 case INTERNALVAR_VALUE
:
1333 addr
= value_contents_writeable (var
->u
.value
);
1336 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1337 value_as_long (newval
), bitpos
, bitsize
);
1339 memcpy (addr
+ offset
, value_contents (newval
),
1340 TYPE_LENGTH (value_type (newval
)));
1344 /* We can never get a component of any other kind. */
1345 internal_error (__FILE__
, __LINE__
, _("set_internalvar_component"));
1350 set_internalvar (struct internalvar
*var
, struct value
*val
)
1352 enum internalvar_kind new_kind
;
1353 union internalvar_data new_data
= { 0 };
1355 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1356 error (_("Cannot overwrite convenience function %s"), var
->name
);
1358 /* Prepare new contents. */
1359 switch (TYPE_CODE (check_typedef (value_type (val
))))
1361 case TYPE_CODE_VOID
:
1362 new_kind
= INTERNALVAR_VOID
;
1365 case TYPE_CODE_INTERNAL_FUNCTION
:
1366 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1367 new_kind
= INTERNALVAR_FUNCTION
;
1368 get_internalvar_function (VALUE_INTERNALVAR (val
),
1369 &new_data
.fn
.function
);
1370 /* Copies created here are never canonical. */
1374 new_kind
= INTERNALVAR_INTEGER
;
1375 new_data
.integer
.type
= value_type (val
);
1376 new_data
.integer
.val
= value_as_long (val
);
1380 new_kind
= INTERNALVAR_POINTER
;
1381 new_data
.pointer
.type
= value_type (val
);
1382 new_data
.pointer
.val
= value_as_address (val
);
1386 new_kind
= INTERNALVAR_VALUE
;
1387 new_data
.value
= value_copy (val
);
1388 new_data
.value
->modifiable
= 1;
1390 /* Force the value to be fetched from the target now, to avoid problems
1391 later when this internalvar is referenced and the target is gone or
1393 if (value_lazy (new_data
.value
))
1394 value_fetch_lazy (new_data
.value
);
1396 /* Release the value from the value chain to prevent it from being
1397 deleted by free_all_values. From here on this function should not
1398 call error () until new_data is installed into the var->u to avoid
1400 release_value (new_data
.value
);
1404 /* Clean up old contents. */
1405 clear_internalvar (var
);
1408 var
->kind
= new_kind
;
1410 /* End code which must not call error(). */
1414 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1416 /* Clean up old contents. */
1417 clear_internalvar (var
);
1419 var
->kind
= INTERNALVAR_INTEGER
;
1420 var
->u
.integer
.type
= NULL
;
1421 var
->u
.integer
.val
= l
;
1425 set_internalvar_string (struct internalvar
*var
, const char *string
)
1427 /* Clean up old contents. */
1428 clear_internalvar (var
);
1430 var
->kind
= INTERNALVAR_STRING
;
1431 var
->u
.string
= xstrdup (string
);
1435 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1437 /* Clean up old contents. */
1438 clear_internalvar (var
);
1440 var
->kind
= INTERNALVAR_FUNCTION
;
1441 var
->u
.fn
.function
= f
;
1442 var
->u
.fn
.canonical
= 1;
1443 /* Variables installed here are always the canonical version. */
1447 clear_internalvar (struct internalvar
*var
)
1449 /* Clean up old contents. */
1452 case INTERNALVAR_VALUE
:
1453 value_free (var
->u
.value
);
1456 case INTERNALVAR_STRING
:
1457 xfree (var
->u
.string
);
1464 /* Reset to void kind. */
1465 var
->kind
= INTERNALVAR_VOID
;
1469 internalvar_name (struct internalvar
*var
)
1474 static struct internal_function
*
1475 create_internal_function (const char *name
,
1476 internal_function_fn handler
, void *cookie
)
1478 struct internal_function
*ifn
= XNEW (struct internal_function
);
1480 ifn
->name
= xstrdup (name
);
1481 ifn
->handler
= handler
;
1482 ifn
->cookie
= cookie
;
1487 value_internal_function_name (struct value
*val
)
1489 struct internal_function
*ifn
;
1492 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1493 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1494 gdb_assert (result
);
1500 call_internal_function (struct gdbarch
*gdbarch
,
1501 const struct language_defn
*language
,
1502 struct value
*func
, int argc
, struct value
**argv
)
1504 struct internal_function
*ifn
;
1507 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1508 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1509 gdb_assert (result
);
1511 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1514 /* The 'function' command. This does nothing -- it is just a
1515 placeholder to let "help function NAME" work. This is also used as
1516 the implementation of the sub-command that is created when
1517 registering an internal function. */
1519 function_command (char *command
, int from_tty
)
1524 /* Clean up if an internal function's command is destroyed. */
1526 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1532 /* Add a new internal function. NAME is the name of the function; DOC
1533 is a documentation string describing the function. HANDLER is
1534 called when the function is invoked. COOKIE is an arbitrary
1535 pointer which is passed to HANDLER and is intended for "user
1538 add_internal_function (const char *name
, const char *doc
,
1539 internal_function_fn handler
, void *cookie
)
1541 struct cmd_list_element
*cmd
;
1542 struct internal_function
*ifn
;
1543 struct internalvar
*var
= lookup_internalvar (name
);
1545 ifn
= create_internal_function (name
, handler
, cookie
);
1546 set_internalvar_function (var
, ifn
);
1548 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1550 cmd
->destroyer
= function_destroyer
;
1553 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1554 prevent cycles / duplicates. */
1557 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1558 htab_t copied_types
)
1560 if (TYPE_OBJFILE (value
->type
) == objfile
)
1561 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1563 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1564 value
->enclosing_type
= copy_type_recursive (objfile
,
1565 value
->enclosing_type
,
1569 /* Likewise for internal variable VAR. */
1572 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1573 htab_t copied_types
)
1577 case INTERNALVAR_INTEGER
:
1578 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1580 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1583 case INTERNALVAR_POINTER
:
1584 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1586 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1589 case INTERNALVAR_VALUE
:
1590 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1595 /* Update the internal variables and value history when OBJFILE is
1596 discarded; we must copy the types out of the objfile. New global types
1597 will be created for every convenience variable which currently points to
1598 this objfile's types, and the convenience variables will be adjusted to
1599 use the new global types. */
1602 preserve_values (struct objfile
*objfile
)
1604 htab_t copied_types
;
1605 struct value_history_chunk
*cur
;
1606 struct internalvar
*var
;
1609 /* Create the hash table. We allocate on the objfile's obstack, since
1610 it is soon to be deleted. */
1611 copied_types
= create_copied_types_hash (objfile
);
1613 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1614 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1616 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1618 for (var
= internalvars
; var
; var
= var
->next
)
1619 preserve_one_internalvar (var
, objfile
, copied_types
);
1621 preserve_python_values (objfile
, copied_types
);
1623 htab_delete (copied_types
);
1627 show_convenience (char *ignore
, int from_tty
)
1629 struct gdbarch
*gdbarch
= get_current_arch ();
1630 struct internalvar
*var
;
1632 struct value_print_options opts
;
1634 get_user_print_options (&opts
);
1635 for (var
= internalvars
; var
; var
= var
->next
)
1641 printf_filtered (("$%s = "), var
->name
);
1642 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1644 printf_filtered (("\n"));
1647 printf_unfiltered (_("No debugger convenience variables now defined.\n"
1648 "Convenience variables have "
1649 "names starting with \"$\";\n"
1650 "use \"set\" as in \"set "
1651 "$foo = 5\" to define them.\n"));
1654 /* Extract a value as a C number (either long or double).
1655 Knows how to convert fixed values to double, or
1656 floating values to long.
1657 Does not deallocate the value. */
1660 value_as_long (struct value
*val
)
1662 /* This coerces arrays and functions, which is necessary (e.g.
1663 in disassemble_command). It also dereferences references, which
1664 I suspect is the most logical thing to do. */
1665 val
= coerce_array (val
);
1666 return unpack_long (value_type (val
), value_contents (val
));
1670 value_as_double (struct value
*val
)
1675 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1677 error (_("Invalid floating value found in program."));
1681 /* Extract a value as a C pointer. Does not deallocate the value.
1682 Note that val's type may not actually be a pointer; value_as_long
1683 handles all the cases. */
1685 value_as_address (struct value
*val
)
1687 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1689 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1690 whether we want this to be true eventually. */
1692 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1693 non-address (e.g. argument to "signal", "info break", etc.), or
1694 for pointers to char, in which the low bits *are* significant. */
1695 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1698 /* There are several targets (IA-64, PowerPC, and others) which
1699 don't represent pointers to functions as simply the address of
1700 the function's entry point. For example, on the IA-64, a
1701 function pointer points to a two-word descriptor, generated by
1702 the linker, which contains the function's entry point, and the
1703 value the IA-64 "global pointer" register should have --- to
1704 support position-independent code. The linker generates
1705 descriptors only for those functions whose addresses are taken.
1707 On such targets, it's difficult for GDB to convert an arbitrary
1708 function address into a function pointer; it has to either find
1709 an existing descriptor for that function, or call malloc and
1710 build its own. On some targets, it is impossible for GDB to
1711 build a descriptor at all: the descriptor must contain a jump
1712 instruction; data memory cannot be executed; and code memory
1715 Upon entry to this function, if VAL is a value of type `function'
1716 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
1717 value_address (val) is the address of the function. This is what
1718 you'll get if you evaluate an expression like `main'. The call
1719 to COERCE_ARRAY below actually does all the usual unary
1720 conversions, which includes converting values of type `function'
1721 to `pointer to function'. This is the challenging conversion
1722 discussed above. Then, `unpack_long' will convert that pointer
1723 back into an address.
1725 So, suppose the user types `disassemble foo' on an architecture
1726 with a strange function pointer representation, on which GDB
1727 cannot build its own descriptors, and suppose further that `foo'
1728 has no linker-built descriptor. The address->pointer conversion
1729 will signal an error and prevent the command from running, even
1730 though the next step would have been to convert the pointer
1731 directly back into the same address.
1733 The following shortcut avoids this whole mess. If VAL is a
1734 function, just return its address directly. */
1735 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
1736 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
1737 return value_address (val
);
1739 val
= coerce_array (val
);
1741 /* Some architectures (e.g. Harvard), map instruction and data
1742 addresses onto a single large unified address space. For
1743 instance: An architecture may consider a large integer in the
1744 range 0x10000000 .. 0x1000ffff to already represent a data
1745 addresses (hence not need a pointer to address conversion) while
1746 a small integer would still need to be converted integer to
1747 pointer to address. Just assume such architectures handle all
1748 integer conversions in a single function. */
1752 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
1753 must admonish GDB hackers to make sure its behavior matches the
1754 compiler's, whenever possible.
1756 In general, I think GDB should evaluate expressions the same way
1757 the compiler does. When the user copies an expression out of
1758 their source code and hands it to a `print' command, they should
1759 get the same value the compiler would have computed. Any
1760 deviation from this rule can cause major confusion and annoyance,
1761 and needs to be justified carefully. In other words, GDB doesn't
1762 really have the freedom to do these conversions in clever and
1765 AndrewC pointed out that users aren't complaining about how GDB
1766 casts integers to pointers; they are complaining that they can't
1767 take an address from a disassembly listing and give it to `x/i'.
1768 This is certainly important.
1770 Adding an architecture method like integer_to_address() certainly
1771 makes it possible for GDB to "get it right" in all circumstances
1772 --- the target has complete control over how things get done, so
1773 people can Do The Right Thing for their target without breaking
1774 anyone else. The standard doesn't specify how integers get
1775 converted to pointers; usually, the ABI doesn't either, but
1776 ABI-specific code is a more reasonable place to handle it. */
1778 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
1779 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
1780 && gdbarch_integer_to_address_p (gdbarch
))
1781 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
1782 value_contents (val
));
1784 return unpack_long (value_type (val
), value_contents (val
));
1788 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1789 as a long, or as a double, assuming the raw data is described
1790 by type TYPE. Knows how to convert different sizes of values
1791 and can convert between fixed and floating point. We don't assume
1792 any alignment for the raw data. Return value is in host byte order.
1794 If you want functions and arrays to be coerced to pointers, and
1795 references to be dereferenced, call value_as_long() instead.
1797 C++: It is assumed that the front-end has taken care of
1798 all matters concerning pointers to members. A pointer
1799 to member which reaches here is considered to be equivalent
1800 to an INT (or some size). After all, it is only an offset. */
1803 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
1805 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1806 enum type_code code
= TYPE_CODE (type
);
1807 int len
= TYPE_LENGTH (type
);
1808 int nosign
= TYPE_UNSIGNED (type
);
1812 case TYPE_CODE_TYPEDEF
:
1813 return unpack_long (check_typedef (type
), valaddr
);
1814 case TYPE_CODE_ENUM
:
1815 case TYPE_CODE_FLAGS
:
1816 case TYPE_CODE_BOOL
:
1818 case TYPE_CODE_CHAR
:
1819 case TYPE_CODE_RANGE
:
1820 case TYPE_CODE_MEMBERPTR
:
1822 return extract_unsigned_integer (valaddr
, len
, byte_order
);
1824 return extract_signed_integer (valaddr
, len
, byte_order
);
1827 return extract_typed_floating (valaddr
, type
);
1829 case TYPE_CODE_DECFLOAT
:
1830 /* libdecnumber has a function to convert from decimal to integer, but
1831 it doesn't work when the decimal number has a fractional part. */
1832 return decimal_to_doublest (valaddr
, len
, byte_order
);
1836 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1837 whether we want this to be true eventually. */
1838 return extract_typed_address (valaddr
, type
);
1841 error (_("Value can't be converted to integer."));
1843 return 0; /* Placate lint. */
1846 /* Return a double value from the specified type and address.
1847 INVP points to an int which is set to 0 for valid value,
1848 1 for invalid value (bad float format). In either case,
1849 the returned double is OK to use. Argument is in target
1850 format, result is in host format. */
1853 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
1855 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
1856 enum type_code code
;
1860 *invp
= 0; /* Assume valid. */
1861 CHECK_TYPEDEF (type
);
1862 code
= TYPE_CODE (type
);
1863 len
= TYPE_LENGTH (type
);
1864 nosign
= TYPE_UNSIGNED (type
);
1865 if (code
== TYPE_CODE_FLT
)
1867 /* NOTE: cagney/2002-02-19: There was a test here to see if the
1868 floating-point value was valid (using the macro
1869 INVALID_FLOAT). That test/macro have been removed.
1871 It turns out that only the VAX defined this macro and then
1872 only in a non-portable way. Fixing the portability problem
1873 wouldn't help since the VAX floating-point code is also badly
1874 bit-rotten. The target needs to add definitions for the
1875 methods gdbarch_float_format and gdbarch_double_format - these
1876 exactly describe the target floating-point format. The
1877 problem here is that the corresponding floatformat_vax_f and
1878 floatformat_vax_d values these methods should be set to are
1879 also not defined either. Oops!
1881 Hopefully someone will add both the missing floatformat
1882 definitions and the new cases for floatformat_is_valid (). */
1884 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
1890 return extract_typed_floating (valaddr
, type
);
1892 else if (code
== TYPE_CODE_DECFLOAT
)
1893 return decimal_to_doublest (valaddr
, len
, byte_order
);
1896 /* Unsigned -- be sure we compensate for signed LONGEST. */
1897 return (ULONGEST
) unpack_long (type
, valaddr
);
1901 /* Signed -- we are OK with unpack_long. */
1902 return unpack_long (type
, valaddr
);
1906 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
1907 as a CORE_ADDR, assuming the raw data is described by type TYPE.
1908 We don't assume any alignment for the raw data. Return value is in
1911 If you want functions and arrays to be coerced to pointers, and
1912 references to be dereferenced, call value_as_address() instead.
1914 C++: It is assumed that the front-end has taken care of
1915 all matters concerning pointers to members. A pointer
1916 to member which reaches here is considered to be equivalent
1917 to an INT (or some size). After all, it is only an offset. */
1920 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
1922 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1923 whether we want this to be true eventually. */
1924 return unpack_long (type
, valaddr
);
1928 /* Get the value of the FIELDNO'th field (which must be static) of
1929 TYPE. Return NULL if the field doesn't exist or has been
1933 value_static_field (struct type
*type
, int fieldno
)
1935 struct value
*retval
;
1937 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
1939 case FIELD_LOC_KIND_PHYSADDR
:
1940 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1941 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
1943 case FIELD_LOC_KIND_PHYSNAME
:
1945 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
1946 /* TYPE_FIELD_NAME (type, fieldno); */
1947 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
1951 /* With some compilers, e.g. HP aCC, static data members are
1952 reported as non-debuggable symbols. */
1953 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
1960 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
1961 SYMBOL_VALUE_ADDRESS (msym
));
1965 retval
= value_of_variable (sym
, NULL
);
1969 gdb_assert_not_reached ("unexpected field location kind");
1975 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
1976 You have to be careful here, since the size of the data area for the value
1977 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
1978 than the old enclosing type, you have to allocate more space for the
1982 set_value_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
1984 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
1986 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
1988 val
->enclosing_type
= new_encl_type
;
1991 /* Given a value ARG1 (offset by OFFSET bytes)
1992 of a struct or union type ARG_TYPE,
1993 extract and return the value of one of its (non-static) fields.
1994 FIELDNO says which field. */
1997 value_primitive_field (struct value
*arg1
, int offset
,
1998 int fieldno
, struct type
*arg_type
)
2003 CHECK_TYPEDEF (arg_type
);
2004 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
2006 /* Call check_typedef on our type to make sure that, if TYPE
2007 is a TYPE_CODE_TYPEDEF, its length is set to the length
2008 of the target type instead of zero. However, we do not
2009 replace the typedef type by the target type, because we want
2010 to keep the typedef in order to be able to print the type
2011 description correctly. */
2012 check_typedef (type
);
2014 /* Handle packed fields */
2016 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
2018 /* Create a new value for the bitfield, with bitpos and bitsize
2019 set. If possible, arrange offset and bitpos so that we can
2020 do a single aligned read of the size of the containing type.
2021 Otherwise, adjust offset to the byte containing the first
2022 bit. Assume that the address, offset, and embedded offset
2023 are sufficiently aligned. */
2024 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
2025 int container_bitsize
= TYPE_LENGTH (type
) * 8;
2027 v
= allocate_value_lazy (type
);
2028 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
2029 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
2030 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
2031 v
->bitpos
= bitpos
% container_bitsize
;
2033 v
->bitpos
= bitpos
% 8;
2034 v
->offset
= (value_embedded_offset (arg1
)
2036 + (bitpos
- v
->bitpos
) / 8);
2038 value_incref (v
->parent
);
2039 if (!value_lazy (arg1
))
2040 value_fetch_lazy (v
);
2042 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
2044 /* This field is actually a base subobject, so preserve the
2045 entire object's contents for later references to virtual
2048 /* Lazy register values with offsets are not supported. */
2049 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2050 value_fetch_lazy (arg1
);
2052 if (value_lazy (arg1
))
2053 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2056 v
= allocate_value (value_enclosing_type (arg1
));
2057 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2058 TYPE_LENGTH (value_enclosing_type (arg1
)));
2061 v
->offset
= value_offset (arg1
);
2062 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2063 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2067 /* Plain old data member */
2068 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2070 /* Lazy register values with offsets are not supported. */
2071 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2072 value_fetch_lazy (arg1
);
2074 if (value_lazy (arg1
))
2075 v
= allocate_value_lazy (type
);
2078 v
= allocate_value (type
);
2079 memcpy (value_contents_raw (v
),
2080 value_contents_raw (arg1
) + offset
,
2081 TYPE_LENGTH (type
));
2083 v
->offset
= (value_offset (arg1
) + offset
2084 + value_embedded_offset (arg1
));
2086 set_value_component_location (v
, arg1
);
2087 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2088 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2092 /* Given a value ARG1 of a struct or union type,
2093 extract and return the value of one of its (non-static) fields.
2094 FIELDNO says which field. */
2097 value_field (struct value
*arg1
, int fieldno
)
2099 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2102 /* Return a non-virtual function as a value.
2103 F is the list of member functions which contains the desired method.
2104 J is an index into F which provides the desired method.
2106 We only use the symbol for its address, so be happy with either a
2107 full symbol or a minimal symbol. */
2110 value_fn_field (struct value
**arg1p
, struct fn_field
*f
,
2111 int j
, struct type
*type
,
2115 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2116 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2118 struct minimal_symbol
*msym
;
2120 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2127 gdb_assert (sym
== NULL
);
2128 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2133 v
= allocate_value (ftype
);
2136 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2140 /* The minimal symbol might point to a function descriptor;
2141 resolve it to the actual code address instead. */
2142 struct objfile
*objfile
= msymbol_objfile (msym
);
2143 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2145 set_value_address (v
,
2146 gdbarch_convert_from_func_ptr_addr
2147 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2152 if (type
!= value_type (*arg1p
))
2153 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2154 value_addr (*arg1p
)));
2156 /* Move the `this' pointer according to the offset.
2157 VALUE_OFFSET (*arg1p) += offset; */
2164 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2165 object at VALADDR. The bitfield starts at BITPOS bits and contains
2168 Extracting bits depends on endianness of the machine. Compute the
2169 number of least significant bits to discard. For big endian machines,
2170 we compute the total number of bits in the anonymous object, subtract
2171 off the bit count from the MSB of the object to the MSB of the
2172 bitfield, then the size of the bitfield, which leaves the LSB discard
2173 count. For little endian machines, the discard count is simply the
2174 number of bits from the LSB of the anonymous object to the LSB of the
2177 If the field is signed, we also do sign extension. */
2180 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2181 int bitpos
, int bitsize
)
2183 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2189 /* Read the minimum number of bytes required; there may not be
2190 enough bytes to read an entire ULONGEST. */
2191 CHECK_TYPEDEF (field_type
);
2193 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2195 bytes_read
= TYPE_LENGTH (field_type
);
2197 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2198 bytes_read
, byte_order
);
2200 /* Extract bits. See comment above. */
2202 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2203 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2205 lsbcount
= (bitpos
% 8);
2208 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2209 If the field is signed, and is negative, then sign extend. */
2211 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2213 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2215 if (!TYPE_UNSIGNED (field_type
))
2217 if (val
& (valmask
^ (valmask
>> 1)))
2226 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2227 VALADDR. See unpack_bits_as_long for more details. */
2230 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2232 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2233 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2234 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2236 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2239 /* Modify the value of a bitfield. ADDR points to a block of memory in
2240 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2241 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2242 indicate which bits (in target bit order) comprise the bitfield.
2243 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
2244 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2247 modify_field (struct type
*type
, gdb_byte
*addr
,
2248 LONGEST fieldval
, int bitpos
, int bitsize
)
2250 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2252 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2255 /* Normalize BITPOS. */
2259 /* If a negative fieldval fits in the field in question, chop
2260 off the sign extension bits. */
2261 if ((~fieldval
& ~(mask
>> 1)) == 0)
2264 /* Warn if value is too big to fit in the field in question. */
2265 if (0 != (fieldval
& ~mask
))
2267 /* FIXME: would like to include fieldval in the message, but
2268 we don't have a sprintf_longest. */
2269 warning (_("Value does not fit in %d bits."), bitsize
);
2271 /* Truncate it, otherwise adjoining fields may be corrupted. */
2275 /* Ensure no bytes outside of the modified ones get accessed as it may cause
2276 false valgrind reports. */
2278 bytesize
= (bitpos
+ bitsize
+ 7) / 8;
2279 oword
= extract_unsigned_integer (addr
, bytesize
, byte_order
);
2281 /* Shifting for bit field depends on endianness of the target machine. */
2282 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2283 bitpos
= bytesize
* 8 - bitpos
- bitsize
;
2285 oword
&= ~(mask
<< bitpos
);
2286 oword
|= fieldval
<< bitpos
;
2288 store_unsigned_integer (addr
, bytesize
, byte_order
, oword
);
2291 /* Pack NUM into BUF using a target format of TYPE. */
2294 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2296 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2299 type
= check_typedef (type
);
2300 len
= TYPE_LENGTH (type
);
2302 switch (TYPE_CODE (type
))
2305 case TYPE_CODE_CHAR
:
2306 case TYPE_CODE_ENUM
:
2307 case TYPE_CODE_FLAGS
:
2308 case TYPE_CODE_BOOL
:
2309 case TYPE_CODE_RANGE
:
2310 case TYPE_CODE_MEMBERPTR
:
2311 store_signed_integer (buf
, len
, byte_order
, num
);
2316 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2320 error (_("Unexpected type (%d) encountered for integer constant."),
2326 /* Pack NUM into BUF using a target format of TYPE. */
2329 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2332 enum bfd_endian byte_order
;
2334 type
= check_typedef (type
);
2335 len
= TYPE_LENGTH (type
);
2336 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2338 switch (TYPE_CODE (type
))
2341 case TYPE_CODE_CHAR
:
2342 case TYPE_CODE_ENUM
:
2343 case TYPE_CODE_FLAGS
:
2344 case TYPE_CODE_BOOL
:
2345 case TYPE_CODE_RANGE
:
2346 case TYPE_CODE_MEMBERPTR
:
2347 store_unsigned_integer (buf
, len
, byte_order
, num
);
2352 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2356 error (_("Unexpected type (%d) encountered "
2357 "for unsigned integer constant."),
2363 /* Convert C numbers into newly allocated values. */
2366 value_from_longest (struct type
*type
, LONGEST num
)
2368 struct value
*val
= allocate_value (type
);
2370 pack_long (value_contents_raw (val
), type
, num
);
2375 /* Convert C unsigned numbers into newly allocated values. */
2378 value_from_ulongest (struct type
*type
, ULONGEST num
)
2380 struct value
*val
= allocate_value (type
);
2382 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2388 /* Create a value representing a pointer of type TYPE to the address
2391 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2393 struct value
*val
= allocate_value (type
);
2395 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2400 /* Create a value of type TYPE whose contents come from VALADDR, if it
2401 is non-null, and whose memory address (in the inferior) is
2405 value_from_contents_and_address (struct type
*type
,
2406 const gdb_byte
*valaddr
,
2411 if (valaddr
== NULL
)
2412 v
= allocate_value_lazy (type
);
2415 v
= allocate_value (type
);
2416 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2418 set_value_address (v
, address
);
2419 VALUE_LVAL (v
) = lval_memory
;
2424 value_from_double (struct type
*type
, DOUBLEST num
)
2426 struct value
*val
= allocate_value (type
);
2427 struct type
*base_type
= check_typedef (type
);
2428 enum type_code code
= TYPE_CODE (base_type
);
2430 if (code
== TYPE_CODE_FLT
)
2432 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2435 error (_("Unexpected type encountered for floating constant."));
2441 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2443 struct value
*val
= allocate_value (type
);
2445 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2450 coerce_ref (struct value
*arg
)
2452 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2454 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2455 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2456 unpack_pointer (value_type (arg
),
2457 value_contents (arg
)));
2462 coerce_array (struct value
*arg
)
2466 arg
= coerce_ref (arg
);
2467 type
= check_typedef (value_type (arg
));
2469 switch (TYPE_CODE (type
))
2471 case TYPE_CODE_ARRAY
:
2472 if (!TYPE_VECTOR (type
) && current_language
->c_style_arrays
)
2473 arg
= value_coerce_array (arg
);
2475 case TYPE_CODE_FUNC
:
2476 arg
= value_coerce_function (arg
);
2483 /* Return true if the function returning the specified type is using
2484 the convention of returning structures in memory (passing in the
2485 address as a hidden first parameter). */
2488 using_struct_return (struct gdbarch
*gdbarch
,
2489 struct type
*func_type
, struct type
*value_type
)
2491 enum type_code code
= TYPE_CODE (value_type
);
2493 if (code
== TYPE_CODE_ERROR
)
2494 error (_("Function return type unknown."));
2496 if (code
== TYPE_CODE_VOID
)
2497 /* A void return value is never in memory. See also corresponding
2498 code in "print_return_value". */
2501 /* Probe the architecture for the return-value convention. */
2502 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2504 != RETURN_VALUE_REGISTER_CONVENTION
);
2507 /* Set the initialized field in a value struct. */
2510 set_value_initialized (struct value
*val
, int status
)
2512 val
->initialized
= status
;
2515 /* Return the initialized field in a value struct. */
2518 value_initialized (struct value
*val
)
2520 return val
->initialized
;
2524 _initialize_values (void)
2526 add_cmd ("convenience", no_class
, show_convenience
, _("\
2527 Debugger convenience (\"$foo\") variables.\n\
2528 These variables are created when you assign them values;\n\
2529 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2531 A few convenience variables are given values automatically:\n\
2532 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2533 \"$__\" holds the contents of the last address examined with \"x\"."),
2536 add_cmd ("values", no_class
, show_values
, _("\
2537 Elements of value history around item number IDX (or last ten)."),
2540 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2541 Initialize a convenience variable if necessary.\n\
2542 init-if-undefined VARIABLE = EXPRESSION\n\
2543 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2544 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2545 VARIABLE is already initialized."));
2547 add_prefix_cmd ("function", no_class
, function_command
, _("\
2548 Placeholder command for showing help on convenience functions."),
2549 &functionlist
, "function ", 0, &cmdlist
);