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 /* Defines an [OFFSET, OFFSET + LENGTH) range. */
70 /* Lowest offset in the range. */
73 /* Length of the range. */
77 typedef struct range range_s
;
81 /* Returns true if the ranges defined by [offset1, offset1+len1) and
82 [offset2, offset2+len2) overlap. */
85 ranges_overlap (int offset1
, int len1
,
86 int offset2
, int len2
)
90 l
= max (offset1
, offset2
);
91 h
= min (offset1
+ len1
, offset2
+ len2
);
95 /* Returns true if the first argument is strictly less than the
96 second, useful for VEC_lower_bound. We keep ranges sorted by
97 offset and coalesce overlapping and contiguous ranges, so this just
98 compares the starting offset. */
101 range_lessthan (const range_s
*r1
, const range_s
*r2
)
103 return r1
->offset
< r2
->offset
;
106 /* Returns true if RANGES contains any range that overlaps [OFFSET,
110 ranges_contain (VEC(range_s
) *ranges
, int offset
, int length
)
115 what
.offset
= offset
;
116 what
.length
= length
;
118 /* We keep ranges sorted by offset and coalesce overlapping and
119 contiguous ranges, so to check if a range list contains a given
120 range, we can do a binary search for the position the given range
121 would be inserted if we only considered the starting OFFSET of
122 ranges. We call that position I. Since we also have LENGTH to
123 care for (this is a range afterall), we need to check if the
124 _previous_ range overlaps the I range. E.g.,
128 |---| |---| |------| ... |--|
133 In the case above, the binary search would return `I=1', meaning,
134 this OFFSET should be inserted at position 1, and the current
135 position 1 should be pushed further (and before 2). But, `0'
138 Then we need to check if the I range overlaps the I range itself.
143 |---| |---| |-------| ... |--|
149 i
= VEC_lower_bound (range_s
, ranges
, &what
, range_lessthan
);
153 struct range
*bef
= VEC_index (range_s
, ranges
, i
- 1);
155 if (ranges_overlap (bef
->offset
, bef
->length
, offset
, length
))
159 if (i
< VEC_length (range_s
, ranges
))
161 struct range
*r
= VEC_index (range_s
, ranges
, i
);
163 if (ranges_overlap (r
->offset
, r
->length
, offset
, length
))
170 static struct cmd_list_element
*functionlist
;
174 /* Type of value; either not an lval, or one of the various
175 different possible kinds of lval. */
178 /* Is it modifiable? Only relevant if lval != not_lval. */
181 /* Location of value (if lval). */
184 /* If lval == lval_memory, this is the address in the inferior.
185 If lval == lval_register, this is the byte offset into the
186 registers structure. */
189 /* Pointer to internal variable. */
190 struct internalvar
*internalvar
;
192 /* If lval == lval_computed, this is a set of function pointers
193 to use to access and describe the value, and a closure pointer
197 struct lval_funcs
*funcs
; /* Functions to call. */
198 void *closure
; /* Closure for those functions to use. */
202 /* Describes offset of a value within lval of a structure in bytes.
203 If lval == lval_memory, this is an offset to the address. If
204 lval == lval_register, this is a further offset from
205 location.address within the registers structure. Note also the
206 member embedded_offset below. */
209 /* Only used for bitfields; number of bits contained in them. */
212 /* Only used for bitfields; position of start of field. For
213 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
214 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
217 /* Only used for bitfields; the containing value. This allows a
218 single read from the target when displaying multiple
220 struct value
*parent
;
222 /* Frame register value is relative to. This will be described in
223 the lval enum above as "lval_register". */
224 struct frame_id frame_id
;
226 /* Type of the value. */
229 /* If a value represents a C++ object, then the `type' field gives
230 the object's compile-time type. If the object actually belongs
231 to some class derived from `type', perhaps with other base
232 classes and additional members, then `type' is just a subobject
233 of the real thing, and the full object is probably larger than
234 `type' would suggest.
236 If `type' is a dynamic class (i.e. one with a vtable), then GDB
237 can actually determine the object's run-time type by looking at
238 the run-time type information in the vtable. When this
239 information is available, we may elect to read in the entire
240 object, for several reasons:
242 - When printing the value, the user would probably rather see the
243 full object, not just the limited portion apparent from the
246 - If `type' has virtual base classes, then even printing `type'
247 alone may require reaching outside the `type' portion of the
248 object to wherever the virtual base class has been stored.
250 When we store the entire object, `enclosing_type' is the run-time
251 type -- the complete object -- and `embedded_offset' is the
252 offset of `type' within that larger type, in bytes. The
253 value_contents() macro takes `embedded_offset' into account, so
254 most GDB code continues to see the `type' portion of the value,
255 just as the inferior would.
257 If `type' is a pointer to an object, then `enclosing_type' is a
258 pointer to the object's run-time type, and `pointed_to_offset' is
259 the offset in bytes from the full object to the pointed-to object
260 -- that is, the value `embedded_offset' would have if we followed
261 the pointer and fetched the complete object. (I don't really see
262 the point. Why not just determine the run-time type when you
263 indirect, and avoid the special case? The contents don't matter
264 until you indirect anyway.)
266 If we're not doing anything fancy, `enclosing_type' is equal to
267 `type', and `embedded_offset' is zero, so everything works
269 struct type
*enclosing_type
;
271 int pointed_to_offset
;
273 /* Values are stored in a chain, so that they can be deleted easily
274 over calls to the inferior. Values assigned to internal
275 variables, put into the value history or exposed to Python are
276 taken off this list. */
279 /* Register number if the value is from a register. */
282 /* If zero, contents of this value are in the contents field. If
283 nonzero, contents are in inferior. If the lval field is lval_memory,
284 the contents are in inferior memory at location.address plus offset.
285 The lval field may also be lval_register.
287 WARNING: This field is used by the code which handles watchpoints
288 (see breakpoint.c) to decide whether a particular value can be
289 watched by hardware watchpoints. If the lazy flag is set for
290 some member of a value chain, it is assumed that this member of
291 the chain doesn't need to be watched as part of watching the
292 value itself. This is how GDB avoids watching the entire struct
293 or array when the user wants to watch a single struct member or
294 array element. If you ever change the way lazy flag is set and
295 reset, be sure to consider this use as well! */
298 /* If nonzero, this is the value of a variable which does not
299 actually exist in the program. */
302 /* If value is a variable, is it initialized or not. */
305 /* If value is from the stack. If this is set, read_stack will be
306 used instead of read_memory to enable extra caching. */
309 /* Actual contents of the value. Target byte-order. NULL or not
310 valid if lazy is nonzero. */
313 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
314 rather than available, since the common and default case is for a
315 value to be available. This is filled in at value read time. */
316 VEC(range_s
) *unavailable
;
318 /* The number of references to this value. When a value is created,
319 the value chain holds a reference, so REFERENCE_COUNT is 1. If
320 release_value is called, this value is removed from the chain but
321 the caller of release_value now has a reference to this value.
322 The caller must arrange for a call to value_free later. */
327 value_bytes_available (const struct value
*value
, int offset
, int length
)
329 gdb_assert (!value
->lazy
);
331 return !ranges_contain (value
->unavailable
, offset
, length
);
335 mark_value_bytes_unavailable (struct value
*value
, int offset
, int length
)
340 /* Insert the range sorted. If there's overlap or the new range
341 would be contiguous with an existing range, merge. */
343 newr
.offset
= offset
;
344 newr
.length
= length
;
346 /* Do a binary search for the position the given range would be
347 inserted if we only considered the starting OFFSET of ranges.
348 Call that position I. Since we also have LENGTH to care for
349 (this is a range afterall), we need to check if the _previous_
350 range overlaps the I range. E.g., calling R the new range:
352 #1 - overlaps with previous
356 |---| |---| |------| ... |--|
361 In the case #1 above, the binary search would return `I=1',
362 meaning, this OFFSET should be inserted at position 1, and the
363 current position 1 should be pushed further (and become 2). But,
364 note that `0' overlaps with R, so we want to merge them.
366 A similar consideration needs to be taken if the new range would
367 be contiguous with the previous range:
369 #2 - contiguous with previous
373 |--| |---| |------| ... |--|
378 If there's no overlap with the previous range, as in:
380 #3 - not overlapping and not contiguous
384 |--| |---| |------| ... |--|
391 #4 - R is the range with lowest offset
395 |--| |---| |------| ... |--|
400 ... we just push the new range to I.
402 All the 4 cases above need to consider that the new range may
403 also overlap several of the ranges that follow, or that R may be
404 contiguous with the following range, and merge. E.g.,
406 #5 - overlapping following ranges
409 |------------------------|
410 |--| |---| |------| ... |--|
419 |--| |---| |------| ... |--|
426 i
= VEC_lower_bound (range_s
, value
->unavailable
, &newr
, range_lessthan
);
429 struct range
*bef
= VEC_index (range_s
, value
->unavailable
, i
- i
);
431 if (ranges_overlap (bef
->offset
, bef
->length
, offset
, length
))
434 ULONGEST l
= min (bef
->offset
, offset
);
435 ULONGEST h
= max (bef
->offset
+ bef
->length
, offset
+ length
);
441 else if (offset
== bef
->offset
+ bef
->length
)
444 bef
->length
+= length
;
450 VEC_safe_insert (range_s
, value
->unavailable
, i
, &newr
);
456 VEC_safe_insert (range_s
, value
->unavailable
, i
, &newr
);
459 /* Check whether the ranges following the one we've just added or
460 touched can be folded in (#5 above). */
461 if (i
+ 1 < VEC_length (range_s
, value
->unavailable
))
468 /* Get the range we just touched. */
469 t
= VEC_index (range_s
, value
->unavailable
, i
);
473 for (; VEC_iterate (range_s
, value
->unavailable
, i
, r
); i
++)
474 if (r
->offset
<= t
->offset
+ t
->length
)
478 l
= min (t
->offset
, r
->offset
);
479 h
= max (t
->offset
+ t
->length
, r
->offset
+ r
->length
);
488 /* If we couldn't merge this one, we won't be able to
489 merge following ones either, since the ranges are
490 always sorted by OFFSET. */
495 VEC_block_remove (range_s
, value
->unavailable
, next
, removed
);
499 /* Prototypes for local functions. */
501 static void show_values (char *, int);
503 static void show_convenience (char *, int);
506 /* The value-history records all the values printed
507 by print commands during this session. Each chunk
508 records 60 consecutive values. The first chunk on
509 the chain records the most recent values.
510 The total number of values is in value_history_count. */
512 #define VALUE_HISTORY_CHUNK 60
514 struct value_history_chunk
516 struct value_history_chunk
*next
;
517 struct value
*values
[VALUE_HISTORY_CHUNK
];
520 /* Chain of chunks now in use. */
522 static struct value_history_chunk
*value_history_chain
;
524 static int value_history_count
; /* Abs number of last entry stored. */
527 /* List of all value objects currently allocated
528 (except for those released by calls to release_value)
529 This is so they can be freed after each command. */
531 static struct value
*all_values
;
533 /* Allocate a lazy value for type TYPE. Its actual content is
534 "lazily" allocated too: the content field of the return value is
535 NULL; it will be allocated when it is fetched from the target. */
538 allocate_value_lazy (struct type
*type
)
542 /* Call check_typedef on our type to make sure that, if TYPE
543 is a TYPE_CODE_TYPEDEF, its length is set to the length
544 of the target type instead of zero. However, we do not
545 replace the typedef type by the target type, because we want
546 to keep the typedef in order to be able to set the VAL's type
547 description correctly. */
548 check_typedef (type
);
550 val
= (struct value
*) xzalloc (sizeof (struct value
));
551 val
->contents
= NULL
;
552 val
->next
= all_values
;
555 val
->enclosing_type
= type
;
556 VALUE_LVAL (val
) = not_lval
;
557 val
->location
.address
= 0;
558 VALUE_FRAME_ID (val
) = null_frame_id
;
562 VALUE_REGNUM (val
) = -1;
564 val
->optimized_out
= 0;
565 val
->embedded_offset
= 0;
566 val
->pointed_to_offset
= 0;
568 val
->initialized
= 1; /* Default to initialized. */
570 /* Values start out on the all_values chain. */
571 val
->reference_count
= 1;
576 /* Allocate the contents of VAL if it has not been allocated yet. */
579 allocate_value_contents (struct value
*val
)
582 val
->contents
= (gdb_byte
*) xzalloc (TYPE_LENGTH (val
->enclosing_type
));
585 /* Allocate a value and its contents for type TYPE. */
588 allocate_value (struct type
*type
)
590 struct value
*val
= allocate_value_lazy (type
);
592 allocate_value_contents (val
);
597 /* Allocate a value that has the correct length
598 for COUNT repetitions of type TYPE. */
601 allocate_repeat_value (struct type
*type
, int count
)
603 int low_bound
= current_language
->string_lower_bound
; /* ??? */
604 /* FIXME-type-allocation: need a way to free this type when we are
606 struct type
*array_type
607 = lookup_array_range_type (type
, low_bound
, count
+ low_bound
- 1);
609 return allocate_value (array_type
);
613 allocate_computed_value (struct type
*type
,
614 struct lval_funcs
*funcs
,
617 struct value
*v
= allocate_value_lazy (type
);
619 VALUE_LVAL (v
) = lval_computed
;
620 v
->location
.computed
.funcs
= funcs
;
621 v
->location
.computed
.closure
= closure
;
626 /* Accessor methods. */
629 value_next (struct value
*value
)
635 value_type (const struct value
*value
)
640 deprecated_set_value_type (struct value
*value
, struct type
*type
)
646 value_offset (const struct value
*value
)
648 return value
->offset
;
651 set_value_offset (struct value
*value
, int offset
)
653 value
->offset
= offset
;
657 value_bitpos (const struct value
*value
)
659 return value
->bitpos
;
662 set_value_bitpos (struct value
*value
, int bit
)
668 value_bitsize (const struct value
*value
)
670 return value
->bitsize
;
673 set_value_bitsize (struct value
*value
, int bit
)
675 value
->bitsize
= bit
;
679 value_parent (struct value
*value
)
681 return value
->parent
;
685 value_contents_raw (struct value
*value
)
687 allocate_value_contents (value
);
688 return value
->contents
+ value
->embedded_offset
;
692 value_contents_all_raw (struct value
*value
)
694 allocate_value_contents (value
);
695 return value
->contents
;
699 value_enclosing_type (struct value
*value
)
701 return value
->enclosing_type
;
705 require_not_optimized_out (const struct value
*value
)
707 if (value
->optimized_out
)
708 error (_("value has been optimized out"));
712 require_available (const struct value
*value
)
714 if (!VEC_empty (range_s
, value
->unavailable
))
715 error (_("value is not available"));
719 value_contents_for_printing (struct value
*value
)
722 value_fetch_lazy (value
);
723 return value
->contents
;
727 value_contents_for_printing_const (const struct value
*value
)
729 gdb_assert (!value
->lazy
);
730 return value
->contents
;
734 value_contents_all (struct value
*value
)
736 const gdb_byte
*result
= value_contents_for_printing (value
);
737 require_not_optimized_out (value
);
738 require_available (value
);
743 value_lazy (struct value
*value
)
749 set_value_lazy (struct value
*value
, int val
)
755 value_stack (struct value
*value
)
761 set_value_stack (struct value
*value
, int val
)
767 value_contents (struct value
*value
)
769 const gdb_byte
*result
= value_contents_writeable (value
);
770 require_not_optimized_out (value
);
771 require_available (value
);
776 value_contents_writeable (struct value
*value
)
779 value_fetch_lazy (value
);
780 return value_contents_raw (value
);
783 /* Return non-zero if VAL1 and VAL2 have the same contents. Note that
784 this function is different from value_equal; in C the operator ==
785 can return 0 even if the two values being compared are equal. */
788 value_contents_equal (struct value
*val1
, struct value
*val2
)
794 type1
= check_typedef (value_type (val1
));
795 type2
= check_typedef (value_type (val2
));
796 len
= TYPE_LENGTH (type1
);
797 if (len
!= TYPE_LENGTH (type2
))
800 return (memcmp (value_contents (val1
), value_contents (val2
), len
) == 0);
804 value_optimized_out (struct value
*value
)
806 return value
->optimized_out
;
810 set_value_optimized_out (struct value
*value
, int val
)
812 value
->optimized_out
= val
;
816 value_entirely_optimized_out (const struct value
*value
)
818 if (!value
->optimized_out
)
820 if (value
->lval
!= lval_computed
821 || !value
->location
.computed
.funcs
->check_any_valid
)
823 return !value
->location
.computed
.funcs
->check_any_valid (value
);
827 value_bits_valid (const struct value
*value
, int offset
, int length
)
829 if (value
== NULL
|| !value
->optimized_out
)
831 if (value
->lval
!= lval_computed
832 || !value
->location
.computed
.funcs
->check_validity
)
834 return value
->location
.computed
.funcs
->check_validity (value
, offset
,
839 value_bits_synthetic_pointer (const struct value
*value
,
840 int offset
, int length
)
842 if (value
== NULL
|| value
->lval
!= lval_computed
843 || !value
->location
.computed
.funcs
->check_synthetic_pointer
)
845 return value
->location
.computed
.funcs
->check_synthetic_pointer (value
,
851 value_embedded_offset (struct value
*value
)
853 return value
->embedded_offset
;
857 set_value_embedded_offset (struct value
*value
, int val
)
859 value
->embedded_offset
= val
;
863 value_pointed_to_offset (struct value
*value
)
865 return value
->pointed_to_offset
;
869 set_value_pointed_to_offset (struct value
*value
, int val
)
871 value
->pointed_to_offset
= val
;
875 value_computed_funcs (struct value
*v
)
877 gdb_assert (VALUE_LVAL (v
) == lval_computed
);
879 return v
->location
.computed
.funcs
;
883 value_computed_closure (const struct value
*v
)
885 gdb_assert (v
->lval
== lval_computed
);
887 return v
->location
.computed
.closure
;
891 deprecated_value_lval_hack (struct value
*value
)
897 value_address (const struct value
*value
)
899 if (value
->lval
== lval_internalvar
900 || value
->lval
== lval_internalvar_component
)
902 return value
->location
.address
+ value
->offset
;
906 value_raw_address (struct value
*value
)
908 if (value
->lval
== lval_internalvar
909 || value
->lval
== lval_internalvar_component
)
911 return value
->location
.address
;
915 set_value_address (struct value
*value
, CORE_ADDR addr
)
917 gdb_assert (value
->lval
!= lval_internalvar
918 && value
->lval
!= lval_internalvar_component
);
919 value
->location
.address
= addr
;
922 struct internalvar
**
923 deprecated_value_internalvar_hack (struct value
*value
)
925 return &value
->location
.internalvar
;
929 deprecated_value_frame_id_hack (struct value
*value
)
931 return &value
->frame_id
;
935 deprecated_value_regnum_hack (struct value
*value
)
937 return &value
->regnum
;
941 deprecated_value_modifiable (struct value
*value
)
943 return value
->modifiable
;
946 deprecated_set_value_modifiable (struct value
*value
, int modifiable
)
948 value
->modifiable
= modifiable
;
951 /* Return a mark in the value chain. All values allocated after the
952 mark is obtained (except for those released) are subject to being freed
953 if a subsequent value_free_to_mark is passed the mark. */
960 /* Take a reference to VAL. VAL will not be deallocated until all
961 references are released. */
964 value_incref (struct value
*val
)
966 val
->reference_count
++;
969 /* Release a reference to VAL, which was acquired with value_incref.
970 This function is also called to deallocate values from the value
974 value_free (struct value
*val
)
978 gdb_assert (val
->reference_count
> 0);
979 val
->reference_count
--;
980 if (val
->reference_count
> 0)
983 /* If there's an associated parent value, drop our reference to
985 if (val
->parent
!= NULL
)
986 value_free (val
->parent
);
988 if (VALUE_LVAL (val
) == lval_computed
)
990 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
992 if (funcs
->free_closure
)
993 funcs
->free_closure (val
);
996 xfree (val
->contents
);
997 VEC_free (range_s
, val
->unavailable
);
1002 /* Free all values allocated since MARK was obtained by value_mark
1003 (except for those released). */
1005 value_free_to_mark (struct value
*mark
)
1010 for (val
= all_values
; val
&& val
!= mark
; val
= next
)
1018 /* Free all the values that have been allocated (except for those released).
1019 Call after each command, successful or not.
1020 In practice this is called before each command, which is sufficient. */
1023 free_all_values (void)
1028 for (val
= all_values
; val
; val
= next
)
1037 /* Frees all the elements in a chain of values. */
1040 free_value_chain (struct value
*v
)
1046 next
= value_next (v
);
1051 /* Remove VAL from the chain all_values
1052 so it will not be freed automatically. */
1055 release_value (struct value
*val
)
1059 if (all_values
== val
)
1061 all_values
= val
->next
;
1066 for (v
= all_values
; v
; v
= v
->next
)
1070 v
->next
= val
->next
;
1077 /* Release all values up to mark */
1079 value_release_to_mark (struct value
*mark
)
1084 for (val
= next
= all_values
; next
; next
= next
->next
)
1085 if (next
->next
== mark
)
1087 all_values
= next
->next
;
1095 /* Return a copy of the value ARG.
1096 It contains the same contents, for same memory address,
1097 but it's a different block of storage. */
1100 value_copy (struct value
*arg
)
1102 struct type
*encl_type
= value_enclosing_type (arg
);
1105 if (value_lazy (arg
))
1106 val
= allocate_value_lazy (encl_type
);
1108 val
= allocate_value (encl_type
);
1109 val
->type
= arg
->type
;
1110 VALUE_LVAL (val
) = VALUE_LVAL (arg
);
1111 val
->location
= arg
->location
;
1112 val
->offset
= arg
->offset
;
1113 val
->bitpos
= arg
->bitpos
;
1114 val
->bitsize
= arg
->bitsize
;
1115 VALUE_FRAME_ID (val
) = VALUE_FRAME_ID (arg
);
1116 VALUE_REGNUM (val
) = VALUE_REGNUM (arg
);
1117 val
->lazy
= arg
->lazy
;
1118 val
->optimized_out
= arg
->optimized_out
;
1119 val
->embedded_offset
= value_embedded_offset (arg
);
1120 val
->pointed_to_offset
= arg
->pointed_to_offset
;
1121 val
->modifiable
= arg
->modifiable
;
1122 if (!value_lazy (val
))
1124 memcpy (value_contents_all_raw (val
), value_contents_all_raw (arg
),
1125 TYPE_LENGTH (value_enclosing_type (arg
)));
1128 val
->unavailable
= VEC_copy (range_s
, arg
->unavailable
);
1129 val
->parent
= arg
->parent
;
1131 value_incref (val
->parent
);
1132 if (VALUE_LVAL (val
) == lval_computed
)
1134 struct lval_funcs
*funcs
= val
->location
.computed
.funcs
;
1136 if (funcs
->copy_closure
)
1137 val
->location
.computed
.closure
= funcs
->copy_closure (val
);
1142 /* Return a version of ARG that is non-lvalue. */
1145 value_non_lval (struct value
*arg
)
1147 if (VALUE_LVAL (arg
) != not_lval
)
1149 struct type
*enc_type
= value_enclosing_type (arg
);
1150 struct value
*val
= allocate_value (enc_type
);
1152 memcpy (value_contents_all_raw (val
), value_contents_all (arg
),
1153 TYPE_LENGTH (enc_type
));
1154 val
->type
= arg
->type
;
1155 set_value_embedded_offset (val
, value_embedded_offset (arg
));
1156 set_value_pointed_to_offset (val
, value_pointed_to_offset (arg
));
1163 set_value_component_location (struct value
*component
,
1164 const struct value
*whole
)
1166 if (whole
->lval
== lval_internalvar
)
1167 VALUE_LVAL (component
) = lval_internalvar_component
;
1169 VALUE_LVAL (component
) = whole
->lval
;
1171 component
->location
= whole
->location
;
1172 if (whole
->lval
== lval_computed
)
1174 struct lval_funcs
*funcs
= whole
->location
.computed
.funcs
;
1176 if (funcs
->copy_closure
)
1177 component
->location
.computed
.closure
= funcs
->copy_closure (whole
);
1182 /* Access to the value history. */
1184 /* Record a new value in the value history.
1185 Returns the absolute history index of the entry.
1186 Result of -1 indicates the value was not saved; otherwise it is the
1187 value history index of this new item. */
1190 record_latest_value (struct value
*val
)
1194 /* We don't want this value to have anything to do with the inferior anymore.
1195 In particular, "set $1 = 50" should not affect the variable from which
1196 the value was taken, and fast watchpoints should be able to assume that
1197 a value on the value history never changes. */
1198 if (value_lazy (val
))
1199 value_fetch_lazy (val
);
1200 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1201 from. This is a bit dubious, because then *&$1 does not just return $1
1202 but the current contents of that location. c'est la vie... */
1203 val
->modifiable
= 0;
1204 release_value (val
);
1206 /* Here we treat value_history_count as origin-zero
1207 and applying to the value being stored now. */
1209 i
= value_history_count
% VALUE_HISTORY_CHUNK
;
1212 struct value_history_chunk
*new
1213 = (struct value_history_chunk
*)
1215 xmalloc (sizeof (struct value_history_chunk
));
1216 memset (new->values
, 0, sizeof new->values
);
1217 new->next
= value_history_chain
;
1218 value_history_chain
= new;
1221 value_history_chain
->values
[i
] = val
;
1223 /* Now we regard value_history_count as origin-one
1224 and applying to the value just stored. */
1226 return ++value_history_count
;
1229 /* Return a copy of the value in the history with sequence number NUM. */
1232 access_value_history (int num
)
1234 struct value_history_chunk
*chunk
;
1239 absnum
+= value_history_count
;
1244 error (_("The history is empty."));
1246 error (_("There is only one value in the history."));
1248 error (_("History does not go back to $$%d."), -num
);
1250 if (absnum
> value_history_count
)
1251 error (_("History has not yet reached $%d."), absnum
);
1255 /* Now absnum is always absolute and origin zero. */
1257 chunk
= value_history_chain
;
1258 for (i
= (value_history_count
- 1) / VALUE_HISTORY_CHUNK
1259 - absnum
/ VALUE_HISTORY_CHUNK
;
1261 chunk
= chunk
->next
;
1263 return value_copy (chunk
->values
[absnum
% VALUE_HISTORY_CHUNK
]);
1267 show_values (char *num_exp
, int from_tty
)
1275 /* "show values +" should print from the stored position.
1276 "show values <exp>" should print around value number <exp>. */
1277 if (num_exp
[0] != '+' || num_exp
[1] != '\0')
1278 num
= parse_and_eval_long (num_exp
) - 5;
1282 /* "show values" means print the last 10 values. */
1283 num
= value_history_count
- 9;
1289 for (i
= num
; i
< num
+ 10 && i
<= value_history_count
; i
++)
1291 struct value_print_options opts
;
1293 val
= access_value_history (i
);
1294 printf_filtered (("$%d = "), i
);
1295 get_user_print_options (&opts
);
1296 value_print (val
, gdb_stdout
, &opts
);
1297 printf_filtered (("\n"));
1300 /* The next "show values +" should start after what we just printed. */
1303 /* Hitting just return after this command should do the same thing as
1304 "show values +". If num_exp is null, this is unnecessary, since
1305 "show values +" is not useful after "show values". */
1306 if (from_tty
&& num_exp
)
1313 /* Internal variables. These are variables within the debugger
1314 that hold values assigned by debugger commands.
1315 The user refers to them with a '$' prefix
1316 that does not appear in the variable names stored internally. */
1320 struct internalvar
*next
;
1323 /* We support various different kinds of content of an internal variable.
1324 enum internalvar_kind specifies the kind, and union internalvar_data
1325 provides the data associated with this particular kind. */
1327 enum internalvar_kind
1329 /* The internal variable is empty. */
1332 /* The value of the internal variable is provided directly as
1333 a GDB value object. */
1336 /* A fresh value is computed via a call-back routine on every
1337 access to the internal variable. */
1338 INTERNALVAR_MAKE_VALUE
,
1340 /* The internal variable holds a GDB internal convenience function. */
1341 INTERNALVAR_FUNCTION
,
1343 /* The variable holds an integer value. */
1344 INTERNALVAR_INTEGER
,
1346 /* The variable holds a pointer value. */
1347 INTERNALVAR_POINTER
,
1349 /* The variable holds a GDB-provided string. */
1354 union internalvar_data
1356 /* A value object used with INTERNALVAR_VALUE. */
1357 struct value
*value
;
1359 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1360 internalvar_make_value make_value
;
1362 /* The internal function used with INTERNALVAR_FUNCTION. */
1365 struct internal_function
*function
;
1366 /* True if this is the canonical name for the function. */
1370 /* An integer value used with INTERNALVAR_INTEGER. */
1373 /* If type is non-NULL, it will be used as the type to generate
1374 a value for this internal variable. If type is NULL, a default
1375 integer type for the architecture is used. */
1380 /* A pointer value used with INTERNALVAR_POINTER. */
1387 /* A string value used with INTERNALVAR_STRING. */
1392 static struct internalvar
*internalvars
;
1394 /* If the variable does not already exist create it and give it the
1395 value given. If no value is given then the default is zero. */
1397 init_if_undefined_command (char* args
, int from_tty
)
1399 struct internalvar
* intvar
;
1401 /* Parse the expression - this is taken from set_command(). */
1402 struct expression
*expr
= parse_expression (args
);
1403 register struct cleanup
*old_chain
=
1404 make_cleanup (free_current_contents
, &expr
);
1406 /* Validate the expression.
1407 Was the expression an assignment?
1408 Or even an expression at all? */
1409 if (expr
->nelts
== 0 || expr
->elts
[0].opcode
!= BINOP_ASSIGN
)
1410 error (_("Init-if-undefined requires an assignment expression."));
1412 /* Extract the variable from the parsed expression.
1413 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1414 if (expr
->elts
[1].opcode
!= OP_INTERNALVAR
)
1415 error (_("The first parameter to init-if-undefined "
1416 "should be a GDB variable."));
1417 intvar
= expr
->elts
[2].internalvar
;
1419 /* Only evaluate the expression if the lvalue is void.
1420 This may still fail if the expresssion is invalid. */
1421 if (intvar
->kind
== INTERNALVAR_VOID
)
1422 evaluate_expression (expr
);
1424 do_cleanups (old_chain
);
1428 /* Look up an internal variable with name NAME. NAME should not
1429 normally include a dollar sign.
1431 If the specified internal variable does not exist,
1432 the return value is NULL. */
1434 struct internalvar
*
1435 lookup_only_internalvar (const char *name
)
1437 struct internalvar
*var
;
1439 for (var
= internalvars
; var
; var
= var
->next
)
1440 if (strcmp (var
->name
, name
) == 0)
1447 /* Create an internal variable with name NAME and with a void value.
1448 NAME should not normally include a dollar sign. */
1450 struct internalvar
*
1451 create_internalvar (const char *name
)
1453 struct internalvar
*var
;
1455 var
= (struct internalvar
*) xmalloc (sizeof (struct internalvar
));
1456 var
->name
= concat (name
, (char *)NULL
);
1457 var
->kind
= INTERNALVAR_VOID
;
1458 var
->next
= internalvars
;
1463 /* Create an internal variable with name NAME and register FUN as the
1464 function that value_of_internalvar uses to create a value whenever
1465 this variable is referenced. NAME should not normally include a
1468 struct internalvar
*
1469 create_internalvar_type_lazy (char *name
, internalvar_make_value fun
)
1471 struct internalvar
*var
= create_internalvar (name
);
1473 var
->kind
= INTERNALVAR_MAKE_VALUE
;
1474 var
->u
.make_value
= fun
;
1478 /* Look up an internal variable with name NAME. NAME should not
1479 normally include a dollar sign.
1481 If the specified internal variable does not exist,
1482 one is created, with a void value. */
1484 struct internalvar
*
1485 lookup_internalvar (const char *name
)
1487 struct internalvar
*var
;
1489 var
= lookup_only_internalvar (name
);
1493 return create_internalvar (name
);
1496 /* Return current value of internal variable VAR. For variables that
1497 are not inherently typed, use a value type appropriate for GDBARCH. */
1500 value_of_internalvar (struct gdbarch
*gdbarch
, struct internalvar
*var
)
1503 struct trace_state_variable
*tsv
;
1505 /* If there is a trace state variable of the same name, assume that
1506 is what we really want to see. */
1507 tsv
= find_trace_state_variable (var
->name
);
1510 tsv
->value_known
= target_get_trace_state_variable_value (tsv
->number
,
1512 if (tsv
->value_known
)
1513 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int64
,
1516 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1522 case INTERNALVAR_VOID
:
1523 val
= allocate_value (builtin_type (gdbarch
)->builtin_void
);
1526 case INTERNALVAR_FUNCTION
:
1527 val
= allocate_value (builtin_type (gdbarch
)->internal_fn
);
1530 case INTERNALVAR_INTEGER
:
1531 if (!var
->u
.integer
.type
)
1532 val
= value_from_longest (builtin_type (gdbarch
)->builtin_int
,
1533 var
->u
.integer
.val
);
1535 val
= value_from_longest (var
->u
.integer
.type
, var
->u
.integer
.val
);
1538 case INTERNALVAR_POINTER
:
1539 val
= value_from_pointer (var
->u
.pointer
.type
, var
->u
.pointer
.val
);
1542 case INTERNALVAR_STRING
:
1543 val
= value_cstring (var
->u
.string
, strlen (var
->u
.string
),
1544 builtin_type (gdbarch
)->builtin_char
);
1547 case INTERNALVAR_VALUE
:
1548 val
= value_copy (var
->u
.value
);
1549 if (value_lazy (val
))
1550 value_fetch_lazy (val
);
1553 case INTERNALVAR_MAKE_VALUE
:
1554 val
= (*var
->u
.make_value
) (gdbarch
, var
);
1558 internal_error (__FILE__
, __LINE__
, _("bad kind"));
1561 /* Change the VALUE_LVAL to lval_internalvar so that future operations
1562 on this value go back to affect the original internal variable.
1564 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
1565 no underlying modifyable state in the internal variable.
1567 Likewise, if the variable's value is a computed lvalue, we want
1568 references to it to produce another computed lvalue, where
1569 references and assignments actually operate through the
1570 computed value's functions.
1572 This means that internal variables with computed values
1573 behave a little differently from other internal variables:
1574 assignments to them don't just replace the previous value
1575 altogether. At the moment, this seems like the behavior we
1578 if (var
->kind
!= INTERNALVAR_MAKE_VALUE
1579 && val
->lval
!= lval_computed
)
1581 VALUE_LVAL (val
) = lval_internalvar
;
1582 VALUE_INTERNALVAR (val
) = var
;
1589 get_internalvar_integer (struct internalvar
*var
, LONGEST
*result
)
1593 case INTERNALVAR_INTEGER
:
1594 *result
= var
->u
.integer
.val
;
1603 get_internalvar_function (struct internalvar
*var
,
1604 struct internal_function
**result
)
1608 case INTERNALVAR_FUNCTION
:
1609 *result
= var
->u
.fn
.function
;
1618 set_internalvar_component (struct internalvar
*var
, int offset
, int bitpos
,
1619 int bitsize
, struct value
*newval
)
1625 case INTERNALVAR_VALUE
:
1626 addr
= value_contents_writeable (var
->u
.value
);
1629 modify_field (value_type (var
->u
.value
), addr
+ offset
,
1630 value_as_long (newval
), bitpos
, bitsize
);
1632 memcpy (addr
+ offset
, value_contents (newval
),
1633 TYPE_LENGTH (value_type (newval
)));
1637 /* We can never get a component of any other kind. */
1638 internal_error (__FILE__
, __LINE__
, _("set_internalvar_component"));
1643 set_internalvar (struct internalvar
*var
, struct value
*val
)
1645 enum internalvar_kind new_kind
;
1646 union internalvar_data new_data
= { 0 };
1648 if (var
->kind
== INTERNALVAR_FUNCTION
&& var
->u
.fn
.canonical
)
1649 error (_("Cannot overwrite convenience function %s"), var
->name
);
1651 /* Prepare new contents. */
1652 switch (TYPE_CODE (check_typedef (value_type (val
))))
1654 case TYPE_CODE_VOID
:
1655 new_kind
= INTERNALVAR_VOID
;
1658 case TYPE_CODE_INTERNAL_FUNCTION
:
1659 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1660 new_kind
= INTERNALVAR_FUNCTION
;
1661 get_internalvar_function (VALUE_INTERNALVAR (val
),
1662 &new_data
.fn
.function
);
1663 /* Copies created here are never canonical. */
1667 new_kind
= INTERNALVAR_INTEGER
;
1668 new_data
.integer
.type
= value_type (val
);
1669 new_data
.integer
.val
= value_as_long (val
);
1673 new_kind
= INTERNALVAR_POINTER
;
1674 new_data
.pointer
.type
= value_type (val
);
1675 new_data
.pointer
.val
= value_as_address (val
);
1679 new_kind
= INTERNALVAR_VALUE
;
1680 new_data
.value
= value_copy (val
);
1681 new_data
.value
->modifiable
= 1;
1683 /* Force the value to be fetched from the target now, to avoid problems
1684 later when this internalvar is referenced and the target is gone or
1686 if (value_lazy (new_data
.value
))
1687 value_fetch_lazy (new_data
.value
);
1689 /* Release the value from the value chain to prevent it from being
1690 deleted by free_all_values. From here on this function should not
1691 call error () until new_data is installed into the var->u to avoid
1693 release_value (new_data
.value
);
1697 /* Clean up old contents. */
1698 clear_internalvar (var
);
1701 var
->kind
= new_kind
;
1703 /* End code which must not call error(). */
1707 set_internalvar_integer (struct internalvar
*var
, LONGEST l
)
1709 /* Clean up old contents. */
1710 clear_internalvar (var
);
1712 var
->kind
= INTERNALVAR_INTEGER
;
1713 var
->u
.integer
.type
= NULL
;
1714 var
->u
.integer
.val
= l
;
1718 set_internalvar_string (struct internalvar
*var
, const char *string
)
1720 /* Clean up old contents. */
1721 clear_internalvar (var
);
1723 var
->kind
= INTERNALVAR_STRING
;
1724 var
->u
.string
= xstrdup (string
);
1728 set_internalvar_function (struct internalvar
*var
, struct internal_function
*f
)
1730 /* Clean up old contents. */
1731 clear_internalvar (var
);
1733 var
->kind
= INTERNALVAR_FUNCTION
;
1734 var
->u
.fn
.function
= f
;
1735 var
->u
.fn
.canonical
= 1;
1736 /* Variables installed here are always the canonical version. */
1740 clear_internalvar (struct internalvar
*var
)
1742 /* Clean up old contents. */
1745 case INTERNALVAR_VALUE
:
1746 value_free (var
->u
.value
);
1749 case INTERNALVAR_STRING
:
1750 xfree (var
->u
.string
);
1757 /* Reset to void kind. */
1758 var
->kind
= INTERNALVAR_VOID
;
1762 internalvar_name (struct internalvar
*var
)
1767 static struct internal_function
*
1768 create_internal_function (const char *name
,
1769 internal_function_fn handler
, void *cookie
)
1771 struct internal_function
*ifn
= XNEW (struct internal_function
);
1773 ifn
->name
= xstrdup (name
);
1774 ifn
->handler
= handler
;
1775 ifn
->cookie
= cookie
;
1780 value_internal_function_name (struct value
*val
)
1782 struct internal_function
*ifn
;
1785 gdb_assert (VALUE_LVAL (val
) == lval_internalvar
);
1786 result
= get_internalvar_function (VALUE_INTERNALVAR (val
), &ifn
);
1787 gdb_assert (result
);
1793 call_internal_function (struct gdbarch
*gdbarch
,
1794 const struct language_defn
*language
,
1795 struct value
*func
, int argc
, struct value
**argv
)
1797 struct internal_function
*ifn
;
1800 gdb_assert (VALUE_LVAL (func
) == lval_internalvar
);
1801 result
= get_internalvar_function (VALUE_INTERNALVAR (func
), &ifn
);
1802 gdb_assert (result
);
1804 return (*ifn
->handler
) (gdbarch
, language
, ifn
->cookie
, argc
, argv
);
1807 /* The 'function' command. This does nothing -- it is just a
1808 placeholder to let "help function NAME" work. This is also used as
1809 the implementation of the sub-command that is created when
1810 registering an internal function. */
1812 function_command (char *command
, int from_tty
)
1817 /* Clean up if an internal function's command is destroyed. */
1819 function_destroyer (struct cmd_list_element
*self
, void *ignore
)
1825 /* Add a new internal function. NAME is the name of the function; DOC
1826 is a documentation string describing the function. HANDLER is
1827 called when the function is invoked. COOKIE is an arbitrary
1828 pointer which is passed to HANDLER and is intended for "user
1831 add_internal_function (const char *name
, const char *doc
,
1832 internal_function_fn handler
, void *cookie
)
1834 struct cmd_list_element
*cmd
;
1835 struct internal_function
*ifn
;
1836 struct internalvar
*var
= lookup_internalvar (name
);
1838 ifn
= create_internal_function (name
, handler
, cookie
);
1839 set_internalvar_function (var
, ifn
);
1841 cmd
= add_cmd (xstrdup (name
), no_class
, function_command
, (char *) doc
,
1843 cmd
->destroyer
= function_destroyer
;
1846 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
1847 prevent cycles / duplicates. */
1850 preserve_one_value (struct value
*value
, struct objfile
*objfile
,
1851 htab_t copied_types
)
1853 if (TYPE_OBJFILE (value
->type
) == objfile
)
1854 value
->type
= copy_type_recursive (objfile
, value
->type
, copied_types
);
1856 if (TYPE_OBJFILE (value
->enclosing_type
) == objfile
)
1857 value
->enclosing_type
= copy_type_recursive (objfile
,
1858 value
->enclosing_type
,
1862 /* Likewise for internal variable VAR. */
1865 preserve_one_internalvar (struct internalvar
*var
, struct objfile
*objfile
,
1866 htab_t copied_types
)
1870 case INTERNALVAR_INTEGER
:
1871 if (var
->u
.integer
.type
&& TYPE_OBJFILE (var
->u
.integer
.type
) == objfile
)
1873 = copy_type_recursive (objfile
, var
->u
.integer
.type
, copied_types
);
1876 case INTERNALVAR_POINTER
:
1877 if (TYPE_OBJFILE (var
->u
.pointer
.type
) == objfile
)
1879 = copy_type_recursive (objfile
, var
->u
.pointer
.type
, copied_types
);
1882 case INTERNALVAR_VALUE
:
1883 preserve_one_value (var
->u
.value
, objfile
, copied_types
);
1888 /* Update the internal variables and value history when OBJFILE is
1889 discarded; we must copy the types out of the objfile. New global types
1890 will be created for every convenience variable which currently points to
1891 this objfile's types, and the convenience variables will be adjusted to
1892 use the new global types. */
1895 preserve_values (struct objfile
*objfile
)
1897 htab_t copied_types
;
1898 struct value_history_chunk
*cur
;
1899 struct internalvar
*var
;
1902 /* Create the hash table. We allocate on the objfile's obstack, since
1903 it is soon to be deleted. */
1904 copied_types
= create_copied_types_hash (objfile
);
1906 for (cur
= value_history_chain
; cur
; cur
= cur
->next
)
1907 for (i
= 0; i
< VALUE_HISTORY_CHUNK
; i
++)
1909 preserve_one_value (cur
->values
[i
], objfile
, copied_types
);
1911 for (var
= internalvars
; var
; var
= var
->next
)
1912 preserve_one_internalvar (var
, objfile
, copied_types
);
1914 preserve_python_values (objfile
, copied_types
);
1916 htab_delete (copied_types
);
1920 show_convenience (char *ignore
, int from_tty
)
1922 struct gdbarch
*gdbarch
= get_current_arch ();
1923 struct internalvar
*var
;
1925 struct value_print_options opts
;
1927 get_user_print_options (&opts
);
1928 for (var
= internalvars
; var
; var
= var
->next
)
1934 printf_filtered (("$%s = "), var
->name
);
1935 value_print (value_of_internalvar (gdbarch
, var
), gdb_stdout
,
1937 printf_filtered (("\n"));
1940 printf_unfiltered (_("No debugger convenience variables now defined.\n"
1941 "Convenience variables have "
1942 "names starting with \"$\";\n"
1943 "use \"set\" as in \"set "
1944 "$foo = 5\" to define them.\n"));
1947 /* Extract a value as a C number (either long or double).
1948 Knows how to convert fixed values to double, or
1949 floating values to long.
1950 Does not deallocate the value. */
1953 value_as_long (struct value
*val
)
1955 /* This coerces arrays and functions, which is necessary (e.g.
1956 in disassemble_command). It also dereferences references, which
1957 I suspect is the most logical thing to do. */
1958 val
= coerce_array (val
);
1959 return unpack_long (value_type (val
), value_contents (val
));
1963 value_as_double (struct value
*val
)
1968 foo
= unpack_double (value_type (val
), value_contents (val
), &inv
);
1970 error (_("Invalid floating value found in program."));
1974 /* Extract a value as a C pointer. Does not deallocate the value.
1975 Note that val's type may not actually be a pointer; value_as_long
1976 handles all the cases. */
1978 value_as_address (struct value
*val
)
1980 struct gdbarch
*gdbarch
= get_type_arch (value_type (val
));
1982 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
1983 whether we want this to be true eventually. */
1985 /* gdbarch_addr_bits_remove is wrong if we are being called for a
1986 non-address (e.g. argument to "signal", "info break", etc.), or
1987 for pointers to char, in which the low bits *are* significant. */
1988 return gdbarch_addr_bits_remove (gdbarch
, value_as_long (val
));
1991 /* There are several targets (IA-64, PowerPC, and others) which
1992 don't represent pointers to functions as simply the address of
1993 the function's entry point. For example, on the IA-64, a
1994 function pointer points to a two-word descriptor, generated by
1995 the linker, which contains the function's entry point, and the
1996 value the IA-64 "global pointer" register should have --- to
1997 support position-independent code. The linker generates
1998 descriptors only for those functions whose addresses are taken.
2000 On such targets, it's difficult for GDB to convert an arbitrary
2001 function address into a function pointer; it has to either find
2002 an existing descriptor for that function, or call malloc and
2003 build its own. On some targets, it is impossible for GDB to
2004 build a descriptor at all: the descriptor must contain a jump
2005 instruction; data memory cannot be executed; and code memory
2008 Upon entry to this function, if VAL is a value of type `function'
2009 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2010 value_address (val) is the address of the function. This is what
2011 you'll get if you evaluate an expression like `main'. The call
2012 to COERCE_ARRAY below actually does all the usual unary
2013 conversions, which includes converting values of type `function'
2014 to `pointer to function'. This is the challenging conversion
2015 discussed above. Then, `unpack_long' will convert that pointer
2016 back into an address.
2018 So, suppose the user types `disassemble foo' on an architecture
2019 with a strange function pointer representation, on which GDB
2020 cannot build its own descriptors, and suppose further that `foo'
2021 has no linker-built descriptor. The address->pointer conversion
2022 will signal an error and prevent the command from running, even
2023 though the next step would have been to convert the pointer
2024 directly back into the same address.
2026 The following shortcut avoids this whole mess. If VAL is a
2027 function, just return its address directly. */
2028 if (TYPE_CODE (value_type (val
)) == TYPE_CODE_FUNC
2029 || TYPE_CODE (value_type (val
)) == TYPE_CODE_METHOD
)
2030 return value_address (val
);
2032 val
= coerce_array (val
);
2034 /* Some architectures (e.g. Harvard), map instruction and data
2035 addresses onto a single large unified address space. For
2036 instance: An architecture may consider a large integer in the
2037 range 0x10000000 .. 0x1000ffff to already represent a data
2038 addresses (hence not need a pointer to address conversion) while
2039 a small integer would still need to be converted integer to
2040 pointer to address. Just assume such architectures handle all
2041 integer conversions in a single function. */
2045 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2046 must admonish GDB hackers to make sure its behavior matches the
2047 compiler's, whenever possible.
2049 In general, I think GDB should evaluate expressions the same way
2050 the compiler does. When the user copies an expression out of
2051 their source code and hands it to a `print' command, they should
2052 get the same value the compiler would have computed. Any
2053 deviation from this rule can cause major confusion and annoyance,
2054 and needs to be justified carefully. In other words, GDB doesn't
2055 really have the freedom to do these conversions in clever and
2058 AndrewC pointed out that users aren't complaining about how GDB
2059 casts integers to pointers; they are complaining that they can't
2060 take an address from a disassembly listing and give it to `x/i'.
2061 This is certainly important.
2063 Adding an architecture method like integer_to_address() certainly
2064 makes it possible for GDB to "get it right" in all circumstances
2065 --- the target has complete control over how things get done, so
2066 people can Do The Right Thing for their target without breaking
2067 anyone else. The standard doesn't specify how integers get
2068 converted to pointers; usually, the ABI doesn't either, but
2069 ABI-specific code is a more reasonable place to handle it. */
2071 if (TYPE_CODE (value_type (val
)) != TYPE_CODE_PTR
2072 && TYPE_CODE (value_type (val
)) != TYPE_CODE_REF
2073 && gdbarch_integer_to_address_p (gdbarch
))
2074 return gdbarch_integer_to_address (gdbarch
, value_type (val
),
2075 value_contents (val
));
2077 return unpack_long (value_type (val
), value_contents (val
));
2081 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2082 as a long, or as a double, assuming the raw data is described
2083 by type TYPE. Knows how to convert different sizes of values
2084 and can convert between fixed and floating point. We don't assume
2085 any alignment for the raw data. Return value is in host byte order.
2087 If you want functions and arrays to be coerced to pointers, and
2088 references to be dereferenced, call value_as_long() instead.
2090 C++: It is assumed that the front-end has taken care of
2091 all matters concerning pointers to members. A pointer
2092 to member which reaches here is considered to be equivalent
2093 to an INT (or some size). After all, it is only an offset. */
2096 unpack_long (struct type
*type
, const gdb_byte
*valaddr
)
2098 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2099 enum type_code code
= TYPE_CODE (type
);
2100 int len
= TYPE_LENGTH (type
);
2101 int nosign
= TYPE_UNSIGNED (type
);
2105 case TYPE_CODE_TYPEDEF
:
2106 return unpack_long (check_typedef (type
), valaddr
);
2107 case TYPE_CODE_ENUM
:
2108 case TYPE_CODE_FLAGS
:
2109 case TYPE_CODE_BOOL
:
2111 case TYPE_CODE_CHAR
:
2112 case TYPE_CODE_RANGE
:
2113 case TYPE_CODE_MEMBERPTR
:
2115 return extract_unsigned_integer (valaddr
, len
, byte_order
);
2117 return extract_signed_integer (valaddr
, len
, byte_order
);
2120 return extract_typed_floating (valaddr
, type
);
2122 case TYPE_CODE_DECFLOAT
:
2123 /* libdecnumber has a function to convert from decimal to integer, but
2124 it doesn't work when the decimal number has a fractional part. */
2125 return decimal_to_doublest (valaddr
, len
, byte_order
);
2129 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2130 whether we want this to be true eventually. */
2131 return extract_typed_address (valaddr
, type
);
2134 error (_("Value can't be converted to integer."));
2136 return 0; /* Placate lint. */
2139 /* Return a double value from the specified type and address.
2140 INVP points to an int which is set to 0 for valid value,
2141 1 for invalid value (bad float format). In either case,
2142 the returned double is OK to use. Argument is in target
2143 format, result is in host format. */
2146 unpack_double (struct type
*type
, const gdb_byte
*valaddr
, int *invp
)
2148 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2149 enum type_code code
;
2153 *invp
= 0; /* Assume valid. */
2154 CHECK_TYPEDEF (type
);
2155 code
= TYPE_CODE (type
);
2156 len
= TYPE_LENGTH (type
);
2157 nosign
= TYPE_UNSIGNED (type
);
2158 if (code
== TYPE_CODE_FLT
)
2160 /* NOTE: cagney/2002-02-19: There was a test here to see if the
2161 floating-point value was valid (using the macro
2162 INVALID_FLOAT). That test/macro have been removed.
2164 It turns out that only the VAX defined this macro and then
2165 only in a non-portable way. Fixing the portability problem
2166 wouldn't help since the VAX floating-point code is also badly
2167 bit-rotten. The target needs to add definitions for the
2168 methods gdbarch_float_format and gdbarch_double_format - these
2169 exactly describe the target floating-point format. The
2170 problem here is that the corresponding floatformat_vax_f and
2171 floatformat_vax_d values these methods should be set to are
2172 also not defined either. Oops!
2174 Hopefully someone will add both the missing floatformat
2175 definitions and the new cases for floatformat_is_valid (). */
2177 if (!floatformat_is_valid (floatformat_from_type (type
), valaddr
))
2183 return extract_typed_floating (valaddr
, type
);
2185 else if (code
== TYPE_CODE_DECFLOAT
)
2186 return decimal_to_doublest (valaddr
, len
, byte_order
);
2189 /* Unsigned -- be sure we compensate for signed LONGEST. */
2190 return (ULONGEST
) unpack_long (type
, valaddr
);
2194 /* Signed -- we are OK with unpack_long. */
2195 return unpack_long (type
, valaddr
);
2199 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2200 as a CORE_ADDR, assuming the raw data is described by type TYPE.
2201 We don't assume any alignment for the raw data. Return value is in
2204 If you want functions and arrays to be coerced to pointers, and
2205 references to be dereferenced, call value_as_address() instead.
2207 C++: It is assumed that the front-end has taken care of
2208 all matters concerning pointers to members. A pointer
2209 to member which reaches here is considered to be equivalent
2210 to an INT (or some size). After all, it is only an offset. */
2213 unpack_pointer (struct type
*type
, const gdb_byte
*valaddr
)
2215 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2216 whether we want this to be true eventually. */
2217 return unpack_long (type
, valaddr
);
2221 /* Get the value of the FIELDNO'th field (which must be static) of
2222 TYPE. Return NULL if the field doesn't exist or has been
2226 value_static_field (struct type
*type
, int fieldno
)
2228 struct value
*retval
;
2230 switch (TYPE_FIELD_LOC_KIND (type
, fieldno
))
2232 case FIELD_LOC_KIND_PHYSADDR
:
2233 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
2234 TYPE_FIELD_STATIC_PHYSADDR (type
, fieldno
));
2236 case FIELD_LOC_KIND_PHYSNAME
:
2238 char *phys_name
= TYPE_FIELD_STATIC_PHYSNAME (type
, fieldno
);
2239 /* TYPE_FIELD_NAME (type, fieldno); */
2240 struct symbol
*sym
= lookup_symbol (phys_name
, 0, VAR_DOMAIN
, 0);
2244 /* With some compilers, e.g. HP aCC, static data members are
2245 reported as non-debuggable symbols. */
2246 struct minimal_symbol
*msym
= lookup_minimal_symbol (phys_name
,
2253 retval
= value_at_lazy (TYPE_FIELD_TYPE (type
, fieldno
),
2254 SYMBOL_VALUE_ADDRESS (msym
));
2258 retval
= value_of_variable (sym
, NULL
);
2262 gdb_assert_not_reached ("unexpected field location kind");
2268 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
2269 You have to be careful here, since the size of the data area for the value
2270 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
2271 than the old enclosing type, you have to allocate more space for the
2275 set_value_enclosing_type (struct value
*val
, struct type
*new_encl_type
)
2277 if (TYPE_LENGTH (new_encl_type
) > TYPE_LENGTH (value_enclosing_type (val
)))
2279 (gdb_byte
*) xrealloc (val
->contents
, TYPE_LENGTH (new_encl_type
));
2281 val
->enclosing_type
= new_encl_type
;
2284 /* Given a value ARG1 (offset by OFFSET bytes)
2285 of a struct or union type ARG_TYPE,
2286 extract and return the value of one of its (non-static) fields.
2287 FIELDNO says which field. */
2290 value_primitive_field (struct value
*arg1
, int offset
,
2291 int fieldno
, struct type
*arg_type
)
2296 CHECK_TYPEDEF (arg_type
);
2297 type
= TYPE_FIELD_TYPE (arg_type
, fieldno
);
2299 /* Call check_typedef on our type to make sure that, if TYPE
2300 is a TYPE_CODE_TYPEDEF, its length is set to the length
2301 of the target type instead of zero. However, we do not
2302 replace the typedef type by the target type, because we want
2303 to keep the typedef in order to be able to print the type
2304 description correctly. */
2305 check_typedef (type
);
2307 /* Handle packed fields */
2309 if (TYPE_FIELD_BITSIZE (arg_type
, fieldno
))
2311 /* Create a new value for the bitfield, with bitpos and bitsize
2312 set. If possible, arrange offset and bitpos so that we can
2313 do a single aligned read of the size of the containing type.
2314 Otherwise, adjust offset to the byte containing the first
2315 bit. Assume that the address, offset, and embedded offset
2316 are sufficiently aligned. */
2317 int bitpos
= TYPE_FIELD_BITPOS (arg_type
, fieldno
);
2318 int container_bitsize
= TYPE_LENGTH (type
) * 8;
2320 v
= allocate_value_lazy (type
);
2321 v
->bitsize
= TYPE_FIELD_BITSIZE (arg_type
, fieldno
);
2322 if ((bitpos
% container_bitsize
) + v
->bitsize
<= container_bitsize
2323 && TYPE_LENGTH (type
) <= (int) sizeof (LONGEST
))
2324 v
->bitpos
= bitpos
% container_bitsize
;
2326 v
->bitpos
= bitpos
% 8;
2327 v
->offset
= (value_embedded_offset (arg1
)
2329 + (bitpos
- v
->bitpos
) / 8);
2331 value_incref (v
->parent
);
2332 if (!value_lazy (arg1
))
2333 value_fetch_lazy (v
);
2335 else if (fieldno
< TYPE_N_BASECLASSES (arg_type
))
2337 /* This field is actually a base subobject, so preserve the
2338 entire object's contents for later references to virtual
2341 /* Lazy register values with offsets are not supported. */
2342 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2343 value_fetch_lazy (arg1
);
2345 if (value_lazy (arg1
))
2346 v
= allocate_value_lazy (value_enclosing_type (arg1
));
2349 v
= allocate_value (value_enclosing_type (arg1
));
2350 memcpy (value_contents_all_raw (v
), value_contents_all_raw (arg1
),
2351 TYPE_LENGTH (value_enclosing_type (arg1
)));
2354 v
->offset
= value_offset (arg1
);
2355 v
->embedded_offset
= (offset
+ value_embedded_offset (arg1
)
2356 + TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8);
2360 /* Plain old data member */
2361 offset
+= TYPE_FIELD_BITPOS (arg_type
, fieldno
) / 8;
2363 /* Lazy register values with offsets are not supported. */
2364 if (VALUE_LVAL (arg1
) == lval_register
&& value_lazy (arg1
))
2365 value_fetch_lazy (arg1
);
2367 if (value_lazy (arg1
))
2368 v
= allocate_value_lazy (type
);
2371 v
= allocate_value (type
);
2372 memcpy (value_contents_raw (v
),
2373 value_contents_raw (arg1
) + offset
,
2374 TYPE_LENGTH (type
));
2376 v
->offset
= (value_offset (arg1
) + offset
2377 + value_embedded_offset (arg1
));
2379 set_value_component_location (v
, arg1
);
2380 VALUE_REGNUM (v
) = VALUE_REGNUM (arg1
);
2381 VALUE_FRAME_ID (v
) = VALUE_FRAME_ID (arg1
);
2385 /* Given a value ARG1 of a struct or union type,
2386 extract and return the value of one of its (non-static) fields.
2387 FIELDNO says which field. */
2390 value_field (struct value
*arg1
, int fieldno
)
2392 return value_primitive_field (arg1
, 0, fieldno
, value_type (arg1
));
2395 /* Return a non-virtual function as a value.
2396 F is the list of member functions which contains the desired method.
2397 J is an index into F which provides the desired method.
2399 We only use the symbol for its address, so be happy with either a
2400 full symbol or a minimal symbol. */
2403 value_fn_field (struct value
**arg1p
, struct fn_field
*f
,
2404 int j
, struct type
*type
,
2408 struct type
*ftype
= TYPE_FN_FIELD_TYPE (f
, j
);
2409 char *physname
= TYPE_FN_FIELD_PHYSNAME (f
, j
);
2411 struct minimal_symbol
*msym
;
2413 sym
= lookup_symbol (physname
, 0, VAR_DOMAIN
, 0);
2420 gdb_assert (sym
== NULL
);
2421 msym
= lookup_minimal_symbol (physname
, NULL
, NULL
);
2426 v
= allocate_value (ftype
);
2429 set_value_address (v
, BLOCK_START (SYMBOL_BLOCK_VALUE (sym
)));
2433 /* The minimal symbol might point to a function descriptor;
2434 resolve it to the actual code address instead. */
2435 struct objfile
*objfile
= msymbol_objfile (msym
);
2436 struct gdbarch
*gdbarch
= get_objfile_arch (objfile
);
2438 set_value_address (v
,
2439 gdbarch_convert_from_func_ptr_addr
2440 (gdbarch
, SYMBOL_VALUE_ADDRESS (msym
), ¤t_target
));
2445 if (type
!= value_type (*arg1p
))
2446 *arg1p
= value_ind (value_cast (lookup_pointer_type (type
),
2447 value_addr (*arg1p
)));
2449 /* Move the `this' pointer according to the offset.
2450 VALUE_OFFSET (*arg1p) += offset; */
2457 /* Unpack a bitfield of the specified FIELD_TYPE, from the anonymous
2458 object at VALADDR. The bitfield starts at BITPOS bits and contains
2461 Extracting bits depends on endianness of the machine. Compute the
2462 number of least significant bits to discard. For big endian machines,
2463 we compute the total number of bits in the anonymous object, subtract
2464 off the bit count from the MSB of the object to the MSB of the
2465 bitfield, then the size of the bitfield, which leaves the LSB discard
2466 count. For little endian machines, the discard count is simply the
2467 number of bits from the LSB of the anonymous object to the LSB of the
2470 If the field is signed, we also do sign extension. */
2473 unpack_bits_as_long (struct type
*field_type
, const gdb_byte
*valaddr
,
2474 int bitpos
, int bitsize
)
2476 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (field_type
));
2482 /* Read the minimum number of bytes required; there may not be
2483 enough bytes to read an entire ULONGEST. */
2484 CHECK_TYPEDEF (field_type
);
2486 bytes_read
= ((bitpos
% 8) + bitsize
+ 7) / 8;
2488 bytes_read
= TYPE_LENGTH (field_type
);
2490 val
= extract_unsigned_integer (valaddr
+ bitpos
/ 8,
2491 bytes_read
, byte_order
);
2493 /* Extract bits. See comment above. */
2495 if (gdbarch_bits_big_endian (get_type_arch (field_type
)))
2496 lsbcount
= (bytes_read
* 8 - bitpos
% 8 - bitsize
);
2498 lsbcount
= (bitpos
% 8);
2501 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
2502 If the field is signed, and is negative, then sign extend. */
2504 if ((bitsize
> 0) && (bitsize
< 8 * (int) sizeof (val
)))
2506 valmask
= (((ULONGEST
) 1) << bitsize
) - 1;
2508 if (!TYPE_UNSIGNED (field_type
))
2510 if (val
& (valmask
^ (valmask
>> 1)))
2519 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous object at
2520 VALADDR. See unpack_bits_as_long for more details. */
2523 unpack_field_as_long (struct type
*type
, const gdb_byte
*valaddr
, int fieldno
)
2525 int bitpos
= TYPE_FIELD_BITPOS (type
, fieldno
);
2526 int bitsize
= TYPE_FIELD_BITSIZE (type
, fieldno
);
2527 struct type
*field_type
= TYPE_FIELD_TYPE (type
, fieldno
);
2529 return unpack_bits_as_long (field_type
, valaddr
, bitpos
, bitsize
);
2532 /* Modify the value of a bitfield. ADDR points to a block of memory in
2533 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
2534 is the desired value of the field, in host byte order. BITPOS and BITSIZE
2535 indicate which bits (in target bit order) comprise the bitfield.
2536 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
2537 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
2540 modify_field (struct type
*type
, gdb_byte
*addr
,
2541 LONGEST fieldval
, int bitpos
, int bitsize
)
2543 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2545 ULONGEST mask
= (ULONGEST
) -1 >> (8 * sizeof (ULONGEST
) - bitsize
);
2548 /* Normalize BITPOS. */
2552 /* If a negative fieldval fits in the field in question, chop
2553 off the sign extension bits. */
2554 if ((~fieldval
& ~(mask
>> 1)) == 0)
2557 /* Warn if value is too big to fit in the field in question. */
2558 if (0 != (fieldval
& ~mask
))
2560 /* FIXME: would like to include fieldval in the message, but
2561 we don't have a sprintf_longest. */
2562 warning (_("Value does not fit in %d bits."), bitsize
);
2564 /* Truncate it, otherwise adjoining fields may be corrupted. */
2568 /* Ensure no bytes outside of the modified ones get accessed as it may cause
2569 false valgrind reports. */
2571 bytesize
= (bitpos
+ bitsize
+ 7) / 8;
2572 oword
= extract_unsigned_integer (addr
, bytesize
, byte_order
);
2574 /* Shifting for bit field depends on endianness of the target machine. */
2575 if (gdbarch_bits_big_endian (get_type_arch (type
)))
2576 bitpos
= bytesize
* 8 - bitpos
- bitsize
;
2578 oword
&= ~(mask
<< bitpos
);
2579 oword
|= fieldval
<< bitpos
;
2581 store_unsigned_integer (addr
, bytesize
, byte_order
, oword
);
2584 /* Pack NUM into BUF using a target format of TYPE. */
2587 pack_long (gdb_byte
*buf
, struct type
*type
, LONGEST num
)
2589 enum bfd_endian byte_order
= gdbarch_byte_order (get_type_arch (type
));
2592 type
= check_typedef (type
);
2593 len
= TYPE_LENGTH (type
);
2595 switch (TYPE_CODE (type
))
2598 case TYPE_CODE_CHAR
:
2599 case TYPE_CODE_ENUM
:
2600 case TYPE_CODE_FLAGS
:
2601 case TYPE_CODE_BOOL
:
2602 case TYPE_CODE_RANGE
:
2603 case TYPE_CODE_MEMBERPTR
:
2604 store_signed_integer (buf
, len
, byte_order
, num
);
2609 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2613 error (_("Unexpected type (%d) encountered for integer constant."),
2619 /* Pack NUM into BUF using a target format of TYPE. */
2622 pack_unsigned_long (gdb_byte
*buf
, struct type
*type
, ULONGEST num
)
2625 enum bfd_endian byte_order
;
2627 type
= check_typedef (type
);
2628 len
= TYPE_LENGTH (type
);
2629 byte_order
= gdbarch_byte_order (get_type_arch (type
));
2631 switch (TYPE_CODE (type
))
2634 case TYPE_CODE_CHAR
:
2635 case TYPE_CODE_ENUM
:
2636 case TYPE_CODE_FLAGS
:
2637 case TYPE_CODE_BOOL
:
2638 case TYPE_CODE_RANGE
:
2639 case TYPE_CODE_MEMBERPTR
:
2640 store_unsigned_integer (buf
, len
, byte_order
, num
);
2645 store_typed_address (buf
, type
, (CORE_ADDR
) num
);
2649 error (_("Unexpected type (%d) encountered "
2650 "for unsigned integer constant."),
2656 /* Convert C numbers into newly allocated values. */
2659 value_from_longest (struct type
*type
, LONGEST num
)
2661 struct value
*val
= allocate_value (type
);
2663 pack_long (value_contents_raw (val
), type
, num
);
2668 /* Convert C unsigned numbers into newly allocated values. */
2671 value_from_ulongest (struct type
*type
, ULONGEST num
)
2673 struct value
*val
= allocate_value (type
);
2675 pack_unsigned_long (value_contents_raw (val
), type
, num
);
2681 /* Create a value representing a pointer of type TYPE to the address
2684 value_from_pointer (struct type
*type
, CORE_ADDR addr
)
2686 struct value
*val
= allocate_value (type
);
2688 store_typed_address (value_contents_raw (val
), check_typedef (type
), addr
);
2693 /* Create a value of type TYPE whose contents come from VALADDR, if it
2694 is non-null, and whose memory address (in the inferior) is
2698 value_from_contents_and_address (struct type
*type
,
2699 const gdb_byte
*valaddr
,
2704 if (valaddr
== NULL
)
2705 v
= allocate_value_lazy (type
);
2708 v
= allocate_value (type
);
2709 memcpy (value_contents_raw (v
), valaddr
, TYPE_LENGTH (type
));
2711 set_value_address (v
, address
);
2712 VALUE_LVAL (v
) = lval_memory
;
2717 value_from_double (struct type
*type
, DOUBLEST num
)
2719 struct value
*val
= allocate_value (type
);
2720 struct type
*base_type
= check_typedef (type
);
2721 enum type_code code
= TYPE_CODE (base_type
);
2723 if (code
== TYPE_CODE_FLT
)
2725 store_typed_floating (value_contents_raw (val
), base_type
, num
);
2728 error (_("Unexpected type encountered for floating constant."));
2734 value_from_decfloat (struct type
*type
, const gdb_byte
*dec
)
2736 struct value
*val
= allocate_value (type
);
2738 memcpy (value_contents_raw (val
), dec
, TYPE_LENGTH (type
));
2743 coerce_ref (struct value
*arg
)
2745 struct type
*value_type_arg_tmp
= check_typedef (value_type (arg
));
2747 if (TYPE_CODE (value_type_arg_tmp
) == TYPE_CODE_REF
)
2748 arg
= value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp
),
2749 unpack_pointer (value_type (arg
),
2750 value_contents (arg
)));
2755 coerce_array (struct value
*arg
)
2759 arg
= coerce_ref (arg
);
2760 type
= check_typedef (value_type (arg
));
2762 switch (TYPE_CODE (type
))
2764 case TYPE_CODE_ARRAY
:
2765 if (!TYPE_VECTOR (type
) && current_language
->c_style_arrays
)
2766 arg
= value_coerce_array (arg
);
2768 case TYPE_CODE_FUNC
:
2769 arg
= value_coerce_function (arg
);
2776 /* Return true if the function returning the specified type is using
2777 the convention of returning structures in memory (passing in the
2778 address as a hidden first parameter). */
2781 using_struct_return (struct gdbarch
*gdbarch
,
2782 struct type
*func_type
, struct type
*value_type
)
2784 enum type_code code
= TYPE_CODE (value_type
);
2786 if (code
== TYPE_CODE_ERROR
)
2787 error (_("Function return type unknown."));
2789 if (code
== TYPE_CODE_VOID
)
2790 /* A void return value is never in memory. See also corresponding
2791 code in "print_return_value". */
2794 /* Probe the architecture for the return-value convention. */
2795 return (gdbarch_return_value (gdbarch
, func_type
, value_type
,
2797 != RETURN_VALUE_REGISTER_CONVENTION
);
2800 /* Set the initialized field in a value struct. */
2803 set_value_initialized (struct value
*val
, int status
)
2805 val
->initialized
= status
;
2808 /* Return the initialized field in a value struct. */
2811 value_initialized (struct value
*val
)
2813 return val
->initialized
;
2817 _initialize_values (void)
2819 add_cmd ("convenience", no_class
, show_convenience
, _("\
2820 Debugger convenience (\"$foo\") variables.\n\
2821 These variables are created when you assign them values;\n\
2822 thus, \"print $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
2824 A few convenience variables are given values automatically:\n\
2825 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
2826 \"$__\" holds the contents of the last address examined with \"x\"."),
2829 add_cmd ("values", no_class
, show_values
, _("\
2830 Elements of value history around item number IDX (or last ten)."),
2833 add_com ("init-if-undefined", class_vars
, init_if_undefined_command
, _("\
2834 Initialize a convenience variable if necessary.\n\
2835 init-if-undefined VARIABLE = EXPRESSION\n\
2836 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
2837 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
2838 VARIABLE is already initialized."));
2840 add_prefix_cmd ("function", no_class
, function_command
, _("\
2841 Placeholder command for showing help on convenience functions."),
2842 &functionlist
, "function ", 0, &cmdlist
);