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Add support for printing value of DWARF-based fixed-point type objects
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1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
2
3 Copyright (C) 1986-2020 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20 #include "defs.h"
21 #include "arch-utils.h"
22 #include "symtab.h"
23 #include "gdbtypes.h"
24 #include "value.h"
25 #include "gdbcore.h"
26 #include "command.h"
27 #include "gdbcmd.h"
28 #include "target.h"
29 #include "language.h"
30 #include "demangle.h"
31 #include "regcache.h"
32 #include "block.h"
33 #include "target-float.h"
34 #include "objfiles.h"
35 #include "valprint.h"
36 #include "cli/cli-decode.h"
37 #include "extension.h"
38 #include <ctype.h>
39 #include "tracepoint.h"
40 #include "cp-abi.h"
41 #include "user-regs.h"
42 #include <algorithm>
43 #include "completer.h"
44 #include "gdbsupport/selftest.h"
45 #include "gdbsupport/array-view.h"
46 #include "cli/cli-style.h"
47
48 /* Definition of a user function. */
49 struct internal_function
50 {
51 /* The name of the function. It is a bit odd to have this in the
52 function itself -- the user might use a differently-named
53 convenience variable to hold the function. */
54 char *name;
55
56 /* The handler. */
57 internal_function_fn handler;
58
59 /* User data for the handler. */
60 void *cookie;
61 };
62
63 /* Defines an [OFFSET, OFFSET + LENGTH) range. */
64
65 struct range
66 {
67 /* Lowest offset in the range. */
68 LONGEST offset;
69
70 /* Length of the range. */
71 LONGEST length;
72
73 /* Returns true if THIS is strictly less than OTHER, useful for
74 searching. We keep ranges sorted by offset and coalesce
75 overlapping and contiguous ranges, so this just compares the
76 starting offset. */
77
78 bool operator< (const range &other) const
79 {
80 return offset < other.offset;
81 }
82
83 /* Returns true if THIS is equal to OTHER. */
84 bool operator== (const range &other) const
85 {
86 return offset == other.offset && length == other.length;
87 }
88 };
89
90 /* Returns true if the ranges defined by [offset1, offset1+len1) and
91 [offset2, offset2+len2) overlap. */
92
93 static int
94 ranges_overlap (LONGEST offset1, LONGEST len1,
95 LONGEST offset2, LONGEST len2)
96 {
97 ULONGEST h, l;
98
99 l = std::max (offset1, offset2);
100 h = std::min (offset1 + len1, offset2 + len2);
101 return (l < h);
102 }
103
104 /* Returns true if RANGES contains any range that overlaps [OFFSET,
105 OFFSET+LENGTH). */
106
107 static int
108 ranges_contain (const std::vector<range> &ranges, LONGEST offset,
109 LONGEST length)
110 {
111 range what;
112
113 what.offset = offset;
114 what.length = length;
115
116 /* We keep ranges sorted by offset and coalesce overlapping and
117 contiguous ranges, so to check if a range list contains a given
118 range, we can do a binary search for the position the given range
119 would be inserted if we only considered the starting OFFSET of
120 ranges. We call that position I. Since we also have LENGTH to
121 care for (this is a range afterall), we need to check if the
122 _previous_ range overlaps the I range. E.g.,
123
124 R
125 |---|
126 |---| |---| |------| ... |--|
127 0 1 2 N
128
129 I=1
130
131 In the case above, the binary search would return `I=1', meaning,
132 this OFFSET should be inserted at position 1, and the current
133 position 1 should be pushed further (and before 2). But, `0'
134 overlaps with R.
135
136 Then we need to check if the I range overlaps the I range itself.
137 E.g.,
138
139 R
140 |---|
141 |---| |---| |-------| ... |--|
142 0 1 2 N
143
144 I=1
145 */
146
147
148 auto i = std::lower_bound (ranges.begin (), ranges.end (), what);
149
150 if (i > ranges.begin ())
151 {
152 const struct range &bef = *(i - 1);
153
154 if (ranges_overlap (bef.offset, bef.length, offset, length))
155 return 1;
156 }
157
158 if (i < ranges.end ())
159 {
160 const struct range &r = *i;
161
162 if (ranges_overlap (r.offset, r.length, offset, length))
163 return 1;
164 }
165
166 return 0;
167 }
168
169 static struct cmd_list_element *functionlist;
170
171 /* Note that the fields in this structure are arranged to save a bit
172 of memory. */
173
174 struct value
175 {
176 explicit value (struct type *type_)
177 : modifiable (1),
178 lazy (1),
179 initialized (1),
180 stack (0),
181 type (type_),
182 enclosing_type (type_)
183 {
184 }
185
186 ~value ()
187 {
188 if (VALUE_LVAL (this) == lval_computed)
189 {
190 const struct lval_funcs *funcs = location.computed.funcs;
191
192 if (funcs->free_closure)
193 funcs->free_closure (this);
194 }
195 else if (VALUE_LVAL (this) == lval_xcallable)
196 delete location.xm_worker;
197 }
198
199 DISABLE_COPY_AND_ASSIGN (value);
200
201 /* Type of value; either not an lval, or one of the various
202 different possible kinds of lval. */
203 enum lval_type lval = not_lval;
204
205 /* Is it modifiable? Only relevant if lval != not_lval. */
206 unsigned int modifiable : 1;
207
208 /* If zero, contents of this value are in the contents field. If
209 nonzero, contents are in inferior. If the lval field is lval_memory,
210 the contents are in inferior memory at location.address plus offset.
211 The lval field may also be lval_register.
212
213 WARNING: This field is used by the code which handles watchpoints
214 (see breakpoint.c) to decide whether a particular value can be
215 watched by hardware watchpoints. If the lazy flag is set for
216 some member of a value chain, it is assumed that this member of
217 the chain doesn't need to be watched as part of watching the
218 value itself. This is how GDB avoids watching the entire struct
219 or array when the user wants to watch a single struct member or
220 array element. If you ever change the way lazy flag is set and
221 reset, be sure to consider this use as well! */
222 unsigned int lazy : 1;
223
224 /* If value is a variable, is it initialized or not. */
225 unsigned int initialized : 1;
226
227 /* If value is from the stack. If this is set, read_stack will be
228 used instead of read_memory to enable extra caching. */
229 unsigned int stack : 1;
230
231 /* Location of value (if lval). */
232 union
233 {
234 /* If lval == lval_memory, this is the address in the inferior */
235 CORE_ADDR address;
236
237 /*If lval == lval_register, the value is from a register. */
238 struct
239 {
240 /* Register number. */
241 int regnum;
242 /* Frame ID of "next" frame to which a register value is relative.
243 If the register value is found relative to frame F, then the
244 frame id of F->next will be stored in next_frame_id. */
245 struct frame_id next_frame_id;
246 } reg;
247
248 /* Pointer to internal variable. */
249 struct internalvar *internalvar;
250
251 /* Pointer to xmethod worker. */
252 struct xmethod_worker *xm_worker;
253
254 /* If lval == lval_computed, this is a set of function pointers
255 to use to access and describe the value, and a closure pointer
256 for them to use. */
257 struct
258 {
259 /* Functions to call. */
260 const struct lval_funcs *funcs;
261
262 /* Closure for those functions to use. */
263 void *closure;
264 } computed;
265 } location {};
266
267 /* Describes offset of a value within lval of a structure in target
268 addressable memory units. Note also the member embedded_offset
269 below. */
270 LONGEST offset = 0;
271
272 /* Only used for bitfields; number of bits contained in them. */
273 LONGEST bitsize = 0;
274
275 /* Only used for bitfields; position of start of field. For
276 little-endian targets, it is the position of the LSB. For
277 big-endian targets, it is the position of the MSB. */
278 LONGEST bitpos = 0;
279
280 /* The number of references to this value. When a value is created,
281 the value chain holds a reference, so REFERENCE_COUNT is 1. If
282 release_value is called, this value is removed from the chain but
283 the caller of release_value now has a reference to this value.
284 The caller must arrange for a call to value_free later. */
285 int reference_count = 1;
286
287 /* Only used for bitfields; the containing value. This allows a
288 single read from the target when displaying multiple
289 bitfields. */
290 value_ref_ptr parent;
291
292 /* Type of the value. */
293 struct type *type;
294
295 /* If a value represents a C++ object, then the `type' field gives
296 the object's compile-time type. If the object actually belongs
297 to some class derived from `type', perhaps with other base
298 classes and additional members, then `type' is just a subobject
299 of the real thing, and the full object is probably larger than
300 `type' would suggest.
301
302 If `type' is a dynamic class (i.e. one with a vtable), then GDB
303 can actually determine the object's run-time type by looking at
304 the run-time type information in the vtable. When this
305 information is available, we may elect to read in the entire
306 object, for several reasons:
307
308 - When printing the value, the user would probably rather see the
309 full object, not just the limited portion apparent from the
310 compile-time type.
311
312 - If `type' has virtual base classes, then even printing `type'
313 alone may require reaching outside the `type' portion of the
314 object to wherever the virtual base class has been stored.
315
316 When we store the entire object, `enclosing_type' is the run-time
317 type -- the complete object -- and `embedded_offset' is the
318 offset of `type' within that larger type, in target addressable memory
319 units. The value_contents() macro takes `embedded_offset' into account,
320 so most GDB code continues to see the `type' portion of the value, just
321 as the inferior would.
322
323 If `type' is a pointer to an object, then `enclosing_type' is a
324 pointer to the object's run-time type, and `pointed_to_offset' is
325 the offset in target addressable memory units from the full object
326 to the pointed-to object -- that is, the value `embedded_offset' would
327 have if we followed the pointer and fetched the complete object.
328 (I don't really see the point. Why not just determine the
329 run-time type when you indirect, and avoid the special case? The
330 contents don't matter until you indirect anyway.)
331
332 If we're not doing anything fancy, `enclosing_type' is equal to
333 `type', and `embedded_offset' is zero, so everything works
334 normally. */
335 struct type *enclosing_type;
336 LONGEST embedded_offset = 0;
337 LONGEST pointed_to_offset = 0;
338
339 /* Actual contents of the value. Target byte-order. NULL or not
340 valid if lazy is nonzero. */
341 gdb::unique_xmalloc_ptr<gdb_byte> contents;
342
343 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
344 rather than available, since the common and default case is for a
345 value to be available. This is filled in at value read time.
346 The unavailable ranges are tracked in bits. Note that a contents
347 bit that has been optimized out doesn't really exist in the
348 program, so it can't be marked unavailable either. */
349 std::vector<range> unavailable;
350
351 /* Likewise, but for optimized out contents (a chunk of the value of
352 a variable that does not actually exist in the program). If LVAL
353 is lval_register, this is a register ($pc, $sp, etc., never a
354 program variable) that has not been saved in the frame. Not
355 saved registers and optimized-out program variables values are
356 treated pretty much the same, except not-saved registers have a
357 different string representation and related error strings. */
358 std::vector<range> optimized_out;
359 };
360
361 /* See value.h. */
362
363 struct gdbarch *
364 get_value_arch (const struct value *value)
365 {
366 return get_type_arch (value_type (value));
367 }
368
369 int
370 value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
371 {
372 gdb_assert (!value->lazy);
373
374 return !ranges_contain (value->unavailable, offset, length);
375 }
376
377 int
378 value_bytes_available (const struct value *value,
379 LONGEST offset, LONGEST length)
380 {
381 return value_bits_available (value,
382 offset * TARGET_CHAR_BIT,
383 length * TARGET_CHAR_BIT);
384 }
385
386 int
387 value_bits_any_optimized_out (const struct value *value, int bit_offset, int bit_length)
388 {
389 gdb_assert (!value->lazy);
390
391 return ranges_contain (value->optimized_out, bit_offset, bit_length);
392 }
393
394 int
395 value_entirely_available (struct value *value)
396 {
397 /* We can only tell whether the whole value is available when we try
398 to read it. */
399 if (value->lazy)
400 value_fetch_lazy (value);
401
402 if (value->unavailable.empty ())
403 return 1;
404 return 0;
405 }
406
407 /* Returns true if VALUE is entirely covered by RANGES. If the value
408 is lazy, it'll be read now. Note that RANGE is a pointer to
409 pointer because reading the value might change *RANGE. */
410
411 static int
412 value_entirely_covered_by_range_vector (struct value *value,
413 const std::vector<range> &ranges)
414 {
415 /* We can only tell whether the whole value is optimized out /
416 unavailable when we try to read it. */
417 if (value->lazy)
418 value_fetch_lazy (value);
419
420 if (ranges.size () == 1)
421 {
422 const struct range &t = ranges[0];
423
424 if (t.offset == 0
425 && t.length == (TARGET_CHAR_BIT
426 * TYPE_LENGTH (value_enclosing_type (value))))
427 return 1;
428 }
429
430 return 0;
431 }
432
433 int
434 value_entirely_unavailable (struct value *value)
435 {
436 return value_entirely_covered_by_range_vector (value, value->unavailable);
437 }
438
439 int
440 value_entirely_optimized_out (struct value *value)
441 {
442 return value_entirely_covered_by_range_vector (value, value->optimized_out);
443 }
444
445 /* Insert into the vector pointed to by VECTORP the bit range starting of
446 OFFSET bits, and extending for the next LENGTH bits. */
447
448 static void
449 insert_into_bit_range_vector (std::vector<range> *vectorp,
450 LONGEST offset, LONGEST length)
451 {
452 range newr;
453
454 /* Insert the range sorted. If there's overlap or the new range
455 would be contiguous with an existing range, merge. */
456
457 newr.offset = offset;
458 newr.length = length;
459
460 /* Do a binary search for the position the given range would be
461 inserted if we only considered the starting OFFSET of ranges.
462 Call that position I. Since we also have LENGTH to care for
463 (this is a range afterall), we need to check if the _previous_
464 range overlaps the I range. E.g., calling R the new range:
465
466 #1 - overlaps with previous
467
468 R
469 |-...-|
470 |---| |---| |------| ... |--|
471 0 1 2 N
472
473 I=1
474
475 In the case #1 above, the binary search would return `I=1',
476 meaning, this OFFSET should be inserted at position 1, and the
477 current position 1 should be pushed further (and become 2). But,
478 note that `0' overlaps with R, so we want to merge them.
479
480 A similar consideration needs to be taken if the new range would
481 be contiguous with the previous range:
482
483 #2 - contiguous with previous
484
485 R
486 |-...-|
487 |--| |---| |------| ... |--|
488 0 1 2 N
489
490 I=1
491
492 If there's no overlap with the previous range, as in:
493
494 #3 - not overlapping and not contiguous
495
496 R
497 |-...-|
498 |--| |---| |------| ... |--|
499 0 1 2 N
500
501 I=1
502
503 or if I is 0:
504
505 #4 - R is the range with lowest offset
506
507 R
508 |-...-|
509 |--| |---| |------| ... |--|
510 0 1 2 N
511
512 I=0
513
514 ... we just push the new range to I.
515
516 All the 4 cases above need to consider that the new range may
517 also overlap several of the ranges that follow, or that R may be
518 contiguous with the following range, and merge. E.g.,
519
520 #5 - overlapping following ranges
521
522 R
523 |------------------------|
524 |--| |---| |------| ... |--|
525 0 1 2 N
526
527 I=0
528
529 or:
530
531 R
532 |-------|
533 |--| |---| |------| ... |--|
534 0 1 2 N
535
536 I=1
537
538 */
539
540 auto i = std::lower_bound (vectorp->begin (), vectorp->end (), newr);
541 if (i > vectorp->begin ())
542 {
543 struct range &bef = *(i - 1);
544
545 if (ranges_overlap (bef.offset, bef.length, offset, length))
546 {
547 /* #1 */
548 ULONGEST l = std::min (bef.offset, offset);
549 ULONGEST h = std::max (bef.offset + bef.length, offset + length);
550
551 bef.offset = l;
552 bef.length = h - l;
553 i--;
554 }
555 else if (offset == bef.offset + bef.length)
556 {
557 /* #2 */
558 bef.length += length;
559 i--;
560 }
561 else
562 {
563 /* #3 */
564 i = vectorp->insert (i, newr);
565 }
566 }
567 else
568 {
569 /* #4 */
570 i = vectorp->insert (i, newr);
571 }
572
573 /* Check whether the ranges following the one we've just added or
574 touched can be folded in (#5 above). */
575 if (i != vectorp->end () && i + 1 < vectorp->end ())
576 {
577 int removed = 0;
578 auto next = i + 1;
579
580 /* Get the range we just touched. */
581 struct range &t = *i;
582 removed = 0;
583
584 i = next;
585 for (; i < vectorp->end (); i++)
586 {
587 struct range &r = *i;
588 if (r.offset <= t.offset + t.length)
589 {
590 ULONGEST l, h;
591
592 l = std::min (t.offset, r.offset);
593 h = std::max (t.offset + t.length, r.offset + r.length);
594
595 t.offset = l;
596 t.length = h - l;
597
598 removed++;
599 }
600 else
601 {
602 /* If we couldn't merge this one, we won't be able to
603 merge following ones either, since the ranges are
604 always sorted by OFFSET. */
605 break;
606 }
607 }
608
609 if (removed != 0)
610 vectorp->erase (next, next + removed);
611 }
612 }
613
614 void
615 mark_value_bits_unavailable (struct value *value,
616 LONGEST offset, LONGEST length)
617 {
618 insert_into_bit_range_vector (&value->unavailable, offset, length);
619 }
620
621 void
622 mark_value_bytes_unavailable (struct value *value,
623 LONGEST offset, LONGEST length)
624 {
625 mark_value_bits_unavailable (value,
626 offset * TARGET_CHAR_BIT,
627 length * TARGET_CHAR_BIT);
628 }
629
630 /* Find the first range in RANGES that overlaps the range defined by
631 OFFSET and LENGTH, starting at element POS in the RANGES vector,
632 Returns the index into RANGES where such overlapping range was
633 found, or -1 if none was found. */
634
635 static int
636 find_first_range_overlap (const std::vector<range> *ranges, int pos,
637 LONGEST offset, LONGEST length)
638 {
639 int i;
640
641 for (i = pos; i < ranges->size (); i++)
642 {
643 const range &r = (*ranges)[i];
644 if (ranges_overlap (r.offset, r.length, offset, length))
645 return i;
646 }
647
648 return -1;
649 }
650
651 /* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
652 PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
653 return non-zero.
654
655 It must always be the case that:
656 OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
657
658 It is assumed that memory can be accessed from:
659 PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
660 to:
661 PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
662 / TARGET_CHAR_BIT) */
663 static int
664 memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
665 const gdb_byte *ptr2, size_t offset2_bits,
666 size_t length_bits)
667 {
668 gdb_assert (offset1_bits % TARGET_CHAR_BIT
669 == offset2_bits % TARGET_CHAR_BIT);
670
671 if (offset1_bits % TARGET_CHAR_BIT != 0)
672 {
673 size_t bits;
674 gdb_byte mask, b1, b2;
675
676 /* The offset from the base pointers PTR1 and PTR2 is not a complete
677 number of bytes. A number of bits up to either the next exact
678 byte boundary, or LENGTH_BITS (which ever is sooner) will be
679 compared. */
680 bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
681 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
682 mask = (1 << bits) - 1;
683
684 if (length_bits < bits)
685 {
686 mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
687 bits = length_bits;
688 }
689
690 /* Now load the two bytes and mask off the bits we care about. */
691 b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
692 b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
693
694 if (b1 != b2)
695 return 1;
696
697 /* Now update the length and offsets to take account of the bits
698 we've just compared. */
699 length_bits -= bits;
700 offset1_bits += bits;
701 offset2_bits += bits;
702 }
703
704 if (length_bits % TARGET_CHAR_BIT != 0)
705 {
706 size_t bits;
707 size_t o1, o2;
708 gdb_byte mask, b1, b2;
709
710 /* The length is not an exact number of bytes. After the previous
711 IF.. block then the offsets are byte aligned, or the
712 length is zero (in which case this code is not reached). Compare
713 a number of bits at the end of the region, starting from an exact
714 byte boundary. */
715 bits = length_bits % TARGET_CHAR_BIT;
716 o1 = offset1_bits + length_bits - bits;
717 o2 = offset2_bits + length_bits - bits;
718
719 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
720 mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
721
722 gdb_assert (o1 % TARGET_CHAR_BIT == 0);
723 gdb_assert (o2 % TARGET_CHAR_BIT == 0);
724
725 b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
726 b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
727
728 if (b1 != b2)
729 return 1;
730
731 length_bits -= bits;
732 }
733
734 if (length_bits > 0)
735 {
736 /* We've now taken care of any stray "bits" at the start, or end of
737 the region to compare, the remainder can be covered with a simple
738 memcmp. */
739 gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
740 gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
741 gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
742
743 return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
744 ptr2 + offset2_bits / TARGET_CHAR_BIT,
745 length_bits / TARGET_CHAR_BIT);
746 }
747
748 /* Length is zero, regions match. */
749 return 0;
750 }
751
752 /* Helper struct for find_first_range_overlap_and_match and
753 value_contents_bits_eq. Keep track of which slot of a given ranges
754 vector have we last looked at. */
755
756 struct ranges_and_idx
757 {
758 /* The ranges. */
759 const std::vector<range> *ranges;
760
761 /* The range we've last found in RANGES. Given ranges are sorted,
762 we can start the next lookup here. */
763 int idx;
764 };
765
766 /* Helper function for value_contents_bits_eq. Compare LENGTH bits of
767 RP1's ranges starting at OFFSET1 bits with LENGTH bits of RP2's
768 ranges starting at OFFSET2 bits. Return true if the ranges match
769 and fill in *L and *H with the overlapping window relative to
770 (both) OFFSET1 or OFFSET2. */
771
772 static int
773 find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
774 struct ranges_and_idx *rp2,
775 LONGEST offset1, LONGEST offset2,
776 LONGEST length, ULONGEST *l, ULONGEST *h)
777 {
778 rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
779 offset1, length);
780 rp2->idx = find_first_range_overlap (rp2->ranges, rp2->idx,
781 offset2, length);
782
783 if (rp1->idx == -1 && rp2->idx == -1)
784 {
785 *l = length;
786 *h = length;
787 return 1;
788 }
789 else if (rp1->idx == -1 || rp2->idx == -1)
790 return 0;
791 else
792 {
793 const range *r1, *r2;
794 ULONGEST l1, h1;
795 ULONGEST l2, h2;
796
797 r1 = &(*rp1->ranges)[rp1->idx];
798 r2 = &(*rp2->ranges)[rp2->idx];
799
800 /* Get the unavailable windows intersected by the incoming
801 ranges. The first and last ranges that overlap the argument
802 range may be wider than said incoming arguments ranges. */
803 l1 = std::max (offset1, r1->offset);
804 h1 = std::min (offset1 + length, r1->offset + r1->length);
805
806 l2 = std::max (offset2, r2->offset);
807 h2 = std::min (offset2 + length, offset2 + r2->length);
808
809 /* Make them relative to the respective start offsets, so we can
810 compare them for equality. */
811 l1 -= offset1;
812 h1 -= offset1;
813
814 l2 -= offset2;
815 h2 -= offset2;
816
817 /* Different ranges, no match. */
818 if (l1 != l2 || h1 != h2)
819 return 0;
820
821 *h = h1;
822 *l = l1;
823 return 1;
824 }
825 }
826
827 /* Helper function for value_contents_eq. The only difference is that
828 this function is bit rather than byte based.
829
830 Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits
831 with LENGTH bits of VAL2's contents starting at OFFSET2 bits.
832 Return true if the available bits match. */
833
834 static bool
835 value_contents_bits_eq (const struct value *val1, int offset1,
836 const struct value *val2, int offset2,
837 int length)
838 {
839 /* Each array element corresponds to a ranges source (unavailable,
840 optimized out). '1' is for VAL1, '2' for VAL2. */
841 struct ranges_and_idx rp1[2], rp2[2];
842
843 /* See function description in value.h. */
844 gdb_assert (!val1->lazy && !val2->lazy);
845
846 /* We shouldn't be trying to compare past the end of the values. */
847 gdb_assert (offset1 + length
848 <= TYPE_LENGTH (val1->enclosing_type) * TARGET_CHAR_BIT);
849 gdb_assert (offset2 + length
850 <= TYPE_LENGTH (val2->enclosing_type) * TARGET_CHAR_BIT);
851
852 memset (&rp1, 0, sizeof (rp1));
853 memset (&rp2, 0, sizeof (rp2));
854 rp1[0].ranges = &val1->unavailable;
855 rp2[0].ranges = &val2->unavailable;
856 rp1[1].ranges = &val1->optimized_out;
857 rp2[1].ranges = &val2->optimized_out;
858
859 while (length > 0)
860 {
861 ULONGEST l = 0, h = 0; /* init for gcc -Wall */
862 int i;
863
864 for (i = 0; i < 2; i++)
865 {
866 ULONGEST l_tmp, h_tmp;
867
868 /* The contents only match equal if the invalid/unavailable
869 contents ranges match as well. */
870 if (!find_first_range_overlap_and_match (&rp1[i], &rp2[i],
871 offset1, offset2, length,
872 &l_tmp, &h_tmp))
873 return false;
874
875 /* We're interested in the lowest/first range found. */
876 if (i == 0 || l_tmp < l)
877 {
878 l = l_tmp;
879 h = h_tmp;
880 }
881 }
882
883 /* Compare the available/valid contents. */
884 if (memcmp_with_bit_offsets (val1->contents.get (), offset1,
885 val2->contents.get (), offset2, l) != 0)
886 return false;
887
888 length -= h;
889 offset1 += h;
890 offset2 += h;
891 }
892
893 return true;
894 }
895
896 bool
897 value_contents_eq (const struct value *val1, LONGEST offset1,
898 const struct value *val2, LONGEST offset2,
899 LONGEST length)
900 {
901 return value_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
902 val2, offset2 * TARGET_CHAR_BIT,
903 length * TARGET_CHAR_BIT);
904 }
905
906
907 /* The value-history records all the values printed by print commands
908 during this session. */
909
910 static std::vector<value_ref_ptr> value_history;
911
912 \f
913 /* List of all value objects currently allocated
914 (except for those released by calls to release_value)
915 This is so they can be freed after each command. */
916
917 static std::vector<value_ref_ptr> all_values;
918
919 /* Allocate a lazy value for type TYPE. Its actual content is
920 "lazily" allocated too: the content field of the return value is
921 NULL; it will be allocated when it is fetched from the target. */
922
923 struct value *
924 allocate_value_lazy (struct type *type)
925 {
926 struct value *val;
927
928 /* Call check_typedef on our type to make sure that, if TYPE
929 is a TYPE_CODE_TYPEDEF, its length is set to the length
930 of the target type instead of zero. However, we do not
931 replace the typedef type by the target type, because we want
932 to keep the typedef in order to be able to set the VAL's type
933 description correctly. */
934 check_typedef (type);
935
936 val = new struct value (type);
937
938 /* Values start out on the all_values chain. */
939 all_values.emplace_back (val);
940
941 return val;
942 }
943
944 /* The maximum size, in bytes, that GDB will try to allocate for a value.
945 The initial value of 64k was not selected for any specific reason, it is
946 just a reasonable starting point. */
947
948 static int max_value_size = 65536; /* 64k bytes */
949
950 /* It is critical that the MAX_VALUE_SIZE is at least as big as the size of
951 LONGEST, otherwise GDB will not be able to parse integer values from the
952 CLI; for example if the MAX_VALUE_SIZE could be set to 1 then GDB would
953 be unable to parse "set max-value-size 2".
954
955 As we want a consistent GDB experience across hosts with different sizes
956 of LONGEST, this arbitrary minimum value was selected, so long as this
957 is bigger than LONGEST on all GDB supported hosts we're fine. */
958
959 #define MIN_VALUE_FOR_MAX_VALUE_SIZE 16
960 gdb_static_assert (sizeof (LONGEST) <= MIN_VALUE_FOR_MAX_VALUE_SIZE);
961
962 /* Implement the "set max-value-size" command. */
963
964 static void
965 set_max_value_size (const char *args, int from_tty,
966 struct cmd_list_element *c)
967 {
968 gdb_assert (max_value_size == -1 || max_value_size >= 0);
969
970 if (max_value_size > -1 && max_value_size < MIN_VALUE_FOR_MAX_VALUE_SIZE)
971 {
972 max_value_size = MIN_VALUE_FOR_MAX_VALUE_SIZE;
973 error (_("max-value-size set too low, increasing to %d bytes"),
974 max_value_size);
975 }
976 }
977
978 /* Implement the "show max-value-size" command. */
979
980 static void
981 show_max_value_size (struct ui_file *file, int from_tty,
982 struct cmd_list_element *c, const char *value)
983 {
984 if (max_value_size == -1)
985 fprintf_filtered (file, _("Maximum value size is unlimited.\n"));
986 else
987 fprintf_filtered (file, _("Maximum value size is %d bytes.\n"),
988 max_value_size);
989 }
990
991 /* Called before we attempt to allocate or reallocate a buffer for the
992 contents of a value. TYPE is the type of the value for which we are
993 allocating the buffer. If the buffer is too large (based on the user
994 controllable setting) then throw an error. If this function returns
995 then we should attempt to allocate the buffer. */
996
997 static void
998 check_type_length_before_alloc (const struct type *type)
999 {
1000 ULONGEST length = TYPE_LENGTH (type);
1001
1002 if (max_value_size > -1 && length > max_value_size)
1003 {
1004 if (type->name () != NULL)
1005 error (_("value of type `%s' requires %s bytes, which is more "
1006 "than max-value-size"), type->name (), pulongest (length));
1007 else
1008 error (_("value requires %s bytes, which is more than "
1009 "max-value-size"), pulongest (length));
1010 }
1011 }
1012
1013 /* Allocate the contents of VAL if it has not been allocated yet. */
1014
1015 static void
1016 allocate_value_contents (struct value *val)
1017 {
1018 if (!val->contents)
1019 {
1020 check_type_length_before_alloc (val->enclosing_type);
1021 val->contents.reset
1022 ((gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type)));
1023 }
1024 }
1025
1026 /* Allocate a value and its contents for type TYPE. */
1027
1028 struct value *
1029 allocate_value (struct type *type)
1030 {
1031 struct value *val = allocate_value_lazy (type);
1032
1033 allocate_value_contents (val);
1034 val->lazy = 0;
1035 return val;
1036 }
1037
1038 /* Allocate a value that has the correct length
1039 for COUNT repetitions of type TYPE. */
1040
1041 struct value *
1042 allocate_repeat_value (struct type *type, int count)
1043 {
1044 /* Despite the fact that we are really creating an array of TYPE here, we
1045 use the string lower bound as the array lower bound. This seems to
1046 work fine for now. */
1047 int low_bound = current_language->string_lower_bound ();
1048 /* FIXME-type-allocation: need a way to free this type when we are
1049 done with it. */
1050 struct type *array_type
1051 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
1052
1053 return allocate_value (array_type);
1054 }
1055
1056 struct value *
1057 allocate_computed_value (struct type *type,
1058 const struct lval_funcs *funcs,
1059 void *closure)
1060 {
1061 struct value *v = allocate_value_lazy (type);
1062
1063 VALUE_LVAL (v) = lval_computed;
1064 v->location.computed.funcs = funcs;
1065 v->location.computed.closure = closure;
1066
1067 return v;
1068 }
1069
1070 /* Allocate NOT_LVAL value for type TYPE being OPTIMIZED_OUT. */
1071
1072 struct value *
1073 allocate_optimized_out_value (struct type *type)
1074 {
1075 struct value *retval = allocate_value_lazy (type);
1076
1077 mark_value_bytes_optimized_out (retval, 0, TYPE_LENGTH (type));
1078 set_value_lazy (retval, 0);
1079 return retval;
1080 }
1081
1082 /* Accessor methods. */
1083
1084 struct type *
1085 value_type (const struct value *value)
1086 {
1087 return value->type;
1088 }
1089 void
1090 deprecated_set_value_type (struct value *value, struct type *type)
1091 {
1092 value->type = type;
1093 }
1094
1095 LONGEST
1096 value_offset (const struct value *value)
1097 {
1098 return value->offset;
1099 }
1100 void
1101 set_value_offset (struct value *value, LONGEST offset)
1102 {
1103 value->offset = offset;
1104 }
1105
1106 LONGEST
1107 value_bitpos (const struct value *value)
1108 {
1109 return value->bitpos;
1110 }
1111 void
1112 set_value_bitpos (struct value *value, LONGEST bit)
1113 {
1114 value->bitpos = bit;
1115 }
1116
1117 LONGEST
1118 value_bitsize (const struct value *value)
1119 {
1120 return value->bitsize;
1121 }
1122 void
1123 set_value_bitsize (struct value *value, LONGEST bit)
1124 {
1125 value->bitsize = bit;
1126 }
1127
1128 struct value *
1129 value_parent (const struct value *value)
1130 {
1131 return value->parent.get ();
1132 }
1133
1134 /* See value.h. */
1135
1136 void
1137 set_value_parent (struct value *value, struct value *parent)
1138 {
1139 value->parent = value_ref_ptr::new_reference (parent);
1140 }
1141
1142 gdb_byte *
1143 value_contents_raw (struct value *value)
1144 {
1145 struct gdbarch *arch = get_value_arch (value);
1146 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1147
1148 allocate_value_contents (value);
1149 return value->contents.get () + value->embedded_offset * unit_size;
1150 }
1151
1152 gdb_byte *
1153 value_contents_all_raw (struct value *value)
1154 {
1155 allocate_value_contents (value);
1156 return value->contents.get ();
1157 }
1158
1159 struct type *
1160 value_enclosing_type (const struct value *value)
1161 {
1162 return value->enclosing_type;
1163 }
1164
1165 /* Look at value.h for description. */
1166
1167 struct type *
1168 value_actual_type (struct value *value, int resolve_simple_types,
1169 int *real_type_found)
1170 {
1171 struct value_print_options opts;
1172 struct type *result;
1173
1174 get_user_print_options (&opts);
1175
1176 if (real_type_found)
1177 *real_type_found = 0;
1178 result = value_type (value);
1179 if (opts.objectprint)
1180 {
1181 /* If result's target type is TYPE_CODE_STRUCT, proceed to
1182 fetch its rtti type. */
1183 if ((result->code () == TYPE_CODE_PTR || TYPE_IS_REFERENCE (result))
1184 && (check_typedef (TYPE_TARGET_TYPE (result))->code ()
1185 == TYPE_CODE_STRUCT)
1186 && !value_optimized_out (value))
1187 {
1188 struct type *real_type;
1189
1190 real_type = value_rtti_indirect_type (value, NULL, NULL, NULL);
1191 if (real_type)
1192 {
1193 if (real_type_found)
1194 *real_type_found = 1;
1195 result = real_type;
1196 }
1197 }
1198 else if (resolve_simple_types)
1199 {
1200 if (real_type_found)
1201 *real_type_found = 1;
1202 result = value_enclosing_type (value);
1203 }
1204 }
1205
1206 return result;
1207 }
1208
1209 void
1210 error_value_optimized_out (void)
1211 {
1212 error (_("value has been optimized out"));
1213 }
1214
1215 static void
1216 require_not_optimized_out (const struct value *value)
1217 {
1218 if (!value->optimized_out.empty ())
1219 {
1220 if (value->lval == lval_register)
1221 error (_("register has not been saved in frame"));
1222 else
1223 error_value_optimized_out ();
1224 }
1225 }
1226
1227 static void
1228 require_available (const struct value *value)
1229 {
1230 if (!value->unavailable.empty ())
1231 throw_error (NOT_AVAILABLE_ERROR, _("value is not available"));
1232 }
1233
1234 const gdb_byte *
1235 value_contents_for_printing (struct value *value)
1236 {
1237 if (value->lazy)
1238 value_fetch_lazy (value);
1239 return value->contents.get ();
1240 }
1241
1242 const gdb_byte *
1243 value_contents_for_printing_const (const struct value *value)
1244 {
1245 gdb_assert (!value->lazy);
1246 return value->contents.get ();
1247 }
1248
1249 const gdb_byte *
1250 value_contents_all (struct value *value)
1251 {
1252 const gdb_byte *result = value_contents_for_printing (value);
1253 require_not_optimized_out (value);
1254 require_available (value);
1255 return result;
1256 }
1257
1258 /* Copy ranges in SRC_RANGE that overlap [SRC_BIT_OFFSET,
1259 SRC_BIT_OFFSET+BIT_LENGTH) ranges into *DST_RANGE, adjusted. */
1260
1261 static void
1262 ranges_copy_adjusted (std::vector<range> *dst_range, int dst_bit_offset,
1263 const std::vector<range> &src_range, int src_bit_offset,
1264 int bit_length)
1265 {
1266 for (const range &r : src_range)
1267 {
1268 ULONGEST h, l;
1269
1270 l = std::max (r.offset, (LONGEST) src_bit_offset);
1271 h = std::min (r.offset + r.length,
1272 (LONGEST) src_bit_offset + bit_length);
1273
1274 if (l < h)
1275 insert_into_bit_range_vector (dst_range,
1276 dst_bit_offset + (l - src_bit_offset),
1277 h - l);
1278 }
1279 }
1280
1281 /* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
1282 SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
1283
1284 static void
1285 value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
1286 const struct value *src, int src_bit_offset,
1287 int bit_length)
1288 {
1289 ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
1290 src->unavailable, src_bit_offset,
1291 bit_length);
1292 ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
1293 src->optimized_out, src_bit_offset,
1294 bit_length);
1295 }
1296
1297 /* Copy LENGTH target addressable memory units of SRC value's (all) contents
1298 (value_contents_all) starting at SRC_OFFSET, into DST value's (all)
1299 contents, starting at DST_OFFSET. If unavailable contents are
1300 being copied from SRC, the corresponding DST contents are marked
1301 unavailable accordingly. Neither DST nor SRC may be lazy
1302 values.
1303
1304 It is assumed the contents of DST in the [DST_OFFSET,
1305 DST_OFFSET+LENGTH) range are wholly available. */
1306
1307 void
1308 value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
1309 struct value *src, LONGEST src_offset, LONGEST length)
1310 {
1311 LONGEST src_bit_offset, dst_bit_offset, bit_length;
1312 struct gdbarch *arch = get_value_arch (src);
1313 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1314
1315 /* A lazy DST would make that this copy operation useless, since as
1316 soon as DST's contents were un-lazied (by a later value_contents
1317 call, say), the contents would be overwritten. A lazy SRC would
1318 mean we'd be copying garbage. */
1319 gdb_assert (!dst->lazy && !src->lazy);
1320
1321 /* The overwritten DST range gets unavailability ORed in, not
1322 replaced. Make sure to remember to implement replacing if it
1323 turns out actually necessary. */
1324 gdb_assert (value_bytes_available (dst, dst_offset, length));
1325 gdb_assert (!value_bits_any_optimized_out (dst,
1326 TARGET_CHAR_BIT * dst_offset,
1327 TARGET_CHAR_BIT * length));
1328
1329 /* Copy the data. */
1330 memcpy (value_contents_all_raw (dst) + dst_offset * unit_size,
1331 value_contents_all_raw (src) + src_offset * unit_size,
1332 length * unit_size);
1333
1334 /* Copy the meta-data, adjusted. */
1335 src_bit_offset = src_offset * unit_size * HOST_CHAR_BIT;
1336 dst_bit_offset = dst_offset * unit_size * HOST_CHAR_BIT;
1337 bit_length = length * unit_size * HOST_CHAR_BIT;
1338
1339 value_ranges_copy_adjusted (dst, dst_bit_offset,
1340 src, src_bit_offset,
1341 bit_length);
1342 }
1343
1344 /* Copy LENGTH bytes of SRC value's (all) contents
1345 (value_contents_all) starting at SRC_OFFSET byte, into DST value's
1346 (all) contents, starting at DST_OFFSET. If unavailable contents
1347 are being copied from SRC, the corresponding DST contents are
1348 marked unavailable accordingly. DST must not be lazy. If SRC is
1349 lazy, it will be fetched now.
1350
1351 It is assumed the contents of DST in the [DST_OFFSET,
1352 DST_OFFSET+LENGTH) range are wholly available. */
1353
1354 void
1355 value_contents_copy (struct value *dst, LONGEST dst_offset,
1356 struct value *src, LONGEST src_offset, LONGEST length)
1357 {
1358 if (src->lazy)
1359 value_fetch_lazy (src);
1360
1361 value_contents_copy_raw (dst, dst_offset, src, src_offset, length);
1362 }
1363
1364 int
1365 value_lazy (const struct value *value)
1366 {
1367 return value->lazy;
1368 }
1369
1370 void
1371 set_value_lazy (struct value *value, int val)
1372 {
1373 value->lazy = val;
1374 }
1375
1376 int
1377 value_stack (const struct value *value)
1378 {
1379 return value->stack;
1380 }
1381
1382 void
1383 set_value_stack (struct value *value, int val)
1384 {
1385 value->stack = val;
1386 }
1387
1388 const gdb_byte *
1389 value_contents (struct value *value)
1390 {
1391 const gdb_byte *result = value_contents_writeable (value);
1392 require_not_optimized_out (value);
1393 require_available (value);
1394 return result;
1395 }
1396
1397 gdb_byte *
1398 value_contents_writeable (struct value *value)
1399 {
1400 if (value->lazy)
1401 value_fetch_lazy (value);
1402 return value_contents_raw (value);
1403 }
1404
1405 int
1406 value_optimized_out (struct value *value)
1407 {
1408 /* We can only know if a value is optimized out once we have tried to
1409 fetch it. */
1410 if (value->optimized_out.empty () && value->lazy)
1411 {
1412 try
1413 {
1414 value_fetch_lazy (value);
1415 }
1416 catch (const gdb_exception_error &ex)
1417 {
1418 switch (ex.error)
1419 {
1420 case MEMORY_ERROR:
1421 case OPTIMIZED_OUT_ERROR:
1422 case NOT_AVAILABLE_ERROR:
1423 /* These can normally happen when we try to access an
1424 optimized out or unavailable register, either in a
1425 physical register or spilled to memory. */
1426 break;
1427 default:
1428 throw;
1429 }
1430 }
1431 }
1432
1433 return !value->optimized_out.empty ();
1434 }
1435
1436 /* Mark contents of VALUE as optimized out, starting at OFFSET bytes, and
1437 the following LENGTH bytes. */
1438
1439 void
1440 mark_value_bytes_optimized_out (struct value *value, int offset, int length)
1441 {
1442 mark_value_bits_optimized_out (value,
1443 offset * TARGET_CHAR_BIT,
1444 length * TARGET_CHAR_BIT);
1445 }
1446
1447 /* See value.h. */
1448
1449 void
1450 mark_value_bits_optimized_out (struct value *value,
1451 LONGEST offset, LONGEST length)
1452 {
1453 insert_into_bit_range_vector (&value->optimized_out, offset, length);
1454 }
1455
1456 int
1457 value_bits_synthetic_pointer (const struct value *value,
1458 LONGEST offset, LONGEST length)
1459 {
1460 if (value->lval != lval_computed
1461 || !value->location.computed.funcs->check_synthetic_pointer)
1462 return 0;
1463 return value->location.computed.funcs->check_synthetic_pointer (value,
1464 offset,
1465 length);
1466 }
1467
1468 LONGEST
1469 value_embedded_offset (const struct value *value)
1470 {
1471 return value->embedded_offset;
1472 }
1473
1474 void
1475 set_value_embedded_offset (struct value *value, LONGEST val)
1476 {
1477 value->embedded_offset = val;
1478 }
1479
1480 LONGEST
1481 value_pointed_to_offset (const struct value *value)
1482 {
1483 return value->pointed_to_offset;
1484 }
1485
1486 void
1487 set_value_pointed_to_offset (struct value *value, LONGEST val)
1488 {
1489 value->pointed_to_offset = val;
1490 }
1491
1492 const struct lval_funcs *
1493 value_computed_funcs (const struct value *v)
1494 {
1495 gdb_assert (value_lval_const (v) == lval_computed);
1496
1497 return v->location.computed.funcs;
1498 }
1499
1500 void *
1501 value_computed_closure (const struct value *v)
1502 {
1503 gdb_assert (v->lval == lval_computed);
1504
1505 return v->location.computed.closure;
1506 }
1507
1508 enum lval_type *
1509 deprecated_value_lval_hack (struct value *value)
1510 {
1511 return &value->lval;
1512 }
1513
1514 enum lval_type
1515 value_lval_const (const struct value *value)
1516 {
1517 return value->lval;
1518 }
1519
1520 CORE_ADDR
1521 value_address (const struct value *value)
1522 {
1523 if (value->lval != lval_memory)
1524 return 0;
1525 if (value->parent != NULL)
1526 return value_address (value->parent.get ()) + value->offset;
1527 if (NULL != TYPE_DATA_LOCATION (value_type (value)))
1528 {
1529 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (value_type (value)));
1530 return TYPE_DATA_LOCATION_ADDR (value_type (value));
1531 }
1532
1533 return value->location.address + value->offset;
1534 }
1535
1536 CORE_ADDR
1537 value_raw_address (const struct value *value)
1538 {
1539 if (value->lval != lval_memory)
1540 return 0;
1541 return value->location.address;
1542 }
1543
1544 void
1545 set_value_address (struct value *value, CORE_ADDR addr)
1546 {
1547 gdb_assert (value->lval == lval_memory);
1548 value->location.address = addr;
1549 }
1550
1551 struct internalvar **
1552 deprecated_value_internalvar_hack (struct value *value)
1553 {
1554 return &value->location.internalvar;
1555 }
1556
1557 struct frame_id *
1558 deprecated_value_next_frame_id_hack (struct value *value)
1559 {
1560 gdb_assert (value->lval == lval_register);
1561 return &value->location.reg.next_frame_id;
1562 }
1563
1564 int *
1565 deprecated_value_regnum_hack (struct value *value)
1566 {
1567 gdb_assert (value->lval == lval_register);
1568 return &value->location.reg.regnum;
1569 }
1570
1571 int
1572 deprecated_value_modifiable (const struct value *value)
1573 {
1574 return value->modifiable;
1575 }
1576 \f
1577 /* Return a mark in the value chain. All values allocated after the
1578 mark is obtained (except for those released) are subject to being freed
1579 if a subsequent value_free_to_mark is passed the mark. */
1580 struct value *
1581 value_mark (void)
1582 {
1583 if (all_values.empty ())
1584 return nullptr;
1585 return all_values.back ().get ();
1586 }
1587
1588 /* See value.h. */
1589
1590 void
1591 value_incref (struct value *val)
1592 {
1593 val->reference_count++;
1594 }
1595
1596 /* Release a reference to VAL, which was acquired with value_incref.
1597 This function is also called to deallocate values from the value
1598 chain. */
1599
1600 void
1601 value_decref (struct value *val)
1602 {
1603 if (val != nullptr)
1604 {
1605 gdb_assert (val->reference_count > 0);
1606 val->reference_count--;
1607 if (val->reference_count == 0)
1608 delete val;
1609 }
1610 }
1611
1612 /* Free all values allocated since MARK was obtained by value_mark
1613 (except for those released). */
1614 void
1615 value_free_to_mark (const struct value *mark)
1616 {
1617 auto iter = std::find (all_values.begin (), all_values.end (), mark);
1618 if (iter == all_values.end ())
1619 all_values.clear ();
1620 else
1621 all_values.erase (iter + 1, all_values.end ());
1622 }
1623
1624 /* Remove VAL from the chain all_values
1625 so it will not be freed automatically. */
1626
1627 value_ref_ptr
1628 release_value (struct value *val)
1629 {
1630 if (val == nullptr)
1631 return value_ref_ptr ();
1632
1633 std::vector<value_ref_ptr>::reverse_iterator iter;
1634 for (iter = all_values.rbegin (); iter != all_values.rend (); ++iter)
1635 {
1636 if (*iter == val)
1637 {
1638 value_ref_ptr result = *iter;
1639 all_values.erase (iter.base () - 1);
1640 return result;
1641 }
1642 }
1643
1644 /* We must always return an owned reference. Normally this happens
1645 because we transfer the reference from the value chain, but in
1646 this case the value was not on the chain. */
1647 return value_ref_ptr::new_reference (val);
1648 }
1649
1650 /* See value.h. */
1651
1652 std::vector<value_ref_ptr>
1653 value_release_to_mark (const struct value *mark)
1654 {
1655 std::vector<value_ref_ptr> result;
1656
1657 auto iter = std::find (all_values.begin (), all_values.end (), mark);
1658 if (iter == all_values.end ())
1659 std::swap (result, all_values);
1660 else
1661 {
1662 std::move (iter + 1, all_values.end (), std::back_inserter (result));
1663 all_values.erase (iter + 1, all_values.end ());
1664 }
1665 std::reverse (result.begin (), result.end ());
1666 return result;
1667 }
1668
1669 /* Return a copy of the value ARG.
1670 It contains the same contents, for same memory address,
1671 but it's a different block of storage. */
1672
1673 struct value *
1674 value_copy (struct value *arg)
1675 {
1676 struct type *encl_type = value_enclosing_type (arg);
1677 struct value *val;
1678
1679 if (value_lazy (arg))
1680 val = allocate_value_lazy (encl_type);
1681 else
1682 val = allocate_value (encl_type);
1683 val->type = arg->type;
1684 VALUE_LVAL (val) = VALUE_LVAL (arg);
1685 val->location = arg->location;
1686 val->offset = arg->offset;
1687 val->bitpos = arg->bitpos;
1688 val->bitsize = arg->bitsize;
1689 val->lazy = arg->lazy;
1690 val->embedded_offset = value_embedded_offset (arg);
1691 val->pointed_to_offset = arg->pointed_to_offset;
1692 val->modifiable = arg->modifiable;
1693 if (!value_lazy (val))
1694 {
1695 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
1696 TYPE_LENGTH (value_enclosing_type (arg)));
1697
1698 }
1699 val->unavailable = arg->unavailable;
1700 val->optimized_out = arg->optimized_out;
1701 val->parent = arg->parent;
1702 if (VALUE_LVAL (val) == lval_computed)
1703 {
1704 const struct lval_funcs *funcs = val->location.computed.funcs;
1705
1706 if (funcs->copy_closure)
1707 val->location.computed.closure = funcs->copy_closure (val);
1708 }
1709 return val;
1710 }
1711
1712 /* Return a "const" and/or "volatile" qualified version of the value V.
1713 If CNST is true, then the returned value will be qualified with
1714 "const".
1715 if VOLTL is true, then the returned value will be qualified with
1716 "volatile". */
1717
1718 struct value *
1719 make_cv_value (int cnst, int voltl, struct value *v)
1720 {
1721 struct type *val_type = value_type (v);
1722 struct type *enclosing_type = value_enclosing_type (v);
1723 struct value *cv_val = value_copy (v);
1724
1725 deprecated_set_value_type (cv_val,
1726 make_cv_type (cnst, voltl, val_type, NULL));
1727 set_value_enclosing_type (cv_val,
1728 make_cv_type (cnst, voltl, enclosing_type, NULL));
1729
1730 return cv_val;
1731 }
1732
1733 /* Return a version of ARG that is non-lvalue. */
1734
1735 struct value *
1736 value_non_lval (struct value *arg)
1737 {
1738 if (VALUE_LVAL (arg) != not_lval)
1739 {
1740 struct type *enc_type = value_enclosing_type (arg);
1741 struct value *val = allocate_value (enc_type);
1742
1743 memcpy (value_contents_all_raw (val), value_contents_all (arg),
1744 TYPE_LENGTH (enc_type));
1745 val->type = arg->type;
1746 set_value_embedded_offset (val, value_embedded_offset (arg));
1747 set_value_pointed_to_offset (val, value_pointed_to_offset (arg));
1748 return val;
1749 }
1750 return arg;
1751 }
1752
1753 /* Write contents of V at ADDR and set its lval type to be LVAL_MEMORY. */
1754
1755 void
1756 value_force_lval (struct value *v, CORE_ADDR addr)
1757 {
1758 gdb_assert (VALUE_LVAL (v) == not_lval);
1759
1760 write_memory (addr, value_contents_raw (v), TYPE_LENGTH (value_type (v)));
1761 v->lval = lval_memory;
1762 v->location.address = addr;
1763 }
1764
1765 void
1766 set_value_component_location (struct value *component,
1767 const struct value *whole)
1768 {
1769 struct type *type;
1770
1771 gdb_assert (whole->lval != lval_xcallable);
1772
1773 if (whole->lval == lval_internalvar)
1774 VALUE_LVAL (component) = lval_internalvar_component;
1775 else
1776 VALUE_LVAL (component) = whole->lval;
1777
1778 component->location = whole->location;
1779 if (whole->lval == lval_computed)
1780 {
1781 const struct lval_funcs *funcs = whole->location.computed.funcs;
1782
1783 if (funcs->copy_closure)
1784 component->location.computed.closure = funcs->copy_closure (whole);
1785 }
1786
1787 /* If type has a dynamic resolved location property
1788 update it's value address. */
1789 type = value_type (whole);
1790 if (NULL != TYPE_DATA_LOCATION (type)
1791 && TYPE_DATA_LOCATION_KIND (type) == PROP_CONST)
1792 set_value_address (component, TYPE_DATA_LOCATION_ADDR (type));
1793 }
1794
1795 /* Access to the value history. */
1796
1797 /* Record a new value in the value history.
1798 Returns the absolute history index of the entry. */
1799
1800 int
1801 record_latest_value (struct value *val)
1802 {
1803 /* We don't want this value to have anything to do with the inferior anymore.
1804 In particular, "set $1 = 50" should not affect the variable from which
1805 the value was taken, and fast watchpoints should be able to assume that
1806 a value on the value history never changes. */
1807 if (value_lazy (val))
1808 value_fetch_lazy (val);
1809 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1810 from. This is a bit dubious, because then *&$1 does not just return $1
1811 but the current contents of that location. c'est la vie... */
1812 val->modifiable = 0;
1813
1814 value_history.push_back (release_value (val));
1815
1816 return value_history.size ();
1817 }
1818
1819 /* Return a copy of the value in the history with sequence number NUM. */
1820
1821 struct value *
1822 access_value_history (int num)
1823 {
1824 int absnum = num;
1825
1826 if (absnum <= 0)
1827 absnum += value_history.size ();
1828
1829 if (absnum <= 0)
1830 {
1831 if (num == 0)
1832 error (_("The history is empty."));
1833 else if (num == 1)
1834 error (_("There is only one value in the history."));
1835 else
1836 error (_("History does not go back to $$%d."), -num);
1837 }
1838 if (absnum > value_history.size ())
1839 error (_("History has not yet reached $%d."), absnum);
1840
1841 absnum--;
1842
1843 return value_copy (value_history[absnum].get ());
1844 }
1845
1846 static void
1847 show_values (const char *num_exp, int from_tty)
1848 {
1849 int i;
1850 struct value *val;
1851 static int num = 1;
1852
1853 if (num_exp)
1854 {
1855 /* "show values +" should print from the stored position.
1856 "show values <exp>" should print around value number <exp>. */
1857 if (num_exp[0] != '+' || num_exp[1] != '\0')
1858 num = parse_and_eval_long (num_exp) - 5;
1859 }
1860 else
1861 {
1862 /* "show values" means print the last 10 values. */
1863 num = value_history.size () - 9;
1864 }
1865
1866 if (num <= 0)
1867 num = 1;
1868
1869 for (i = num; i < num + 10 && i <= value_history.size (); i++)
1870 {
1871 struct value_print_options opts;
1872
1873 val = access_value_history (i);
1874 printf_filtered (("$%d = "), i);
1875 get_user_print_options (&opts);
1876 value_print (val, gdb_stdout, &opts);
1877 printf_filtered (("\n"));
1878 }
1879
1880 /* The next "show values +" should start after what we just printed. */
1881 num += 10;
1882
1883 /* Hitting just return after this command should do the same thing as
1884 "show values +". If num_exp is null, this is unnecessary, since
1885 "show values +" is not useful after "show values". */
1886 if (from_tty && num_exp)
1887 set_repeat_arguments ("+");
1888 }
1889 \f
1890 enum internalvar_kind
1891 {
1892 /* The internal variable is empty. */
1893 INTERNALVAR_VOID,
1894
1895 /* The value of the internal variable is provided directly as
1896 a GDB value object. */
1897 INTERNALVAR_VALUE,
1898
1899 /* A fresh value is computed via a call-back routine on every
1900 access to the internal variable. */
1901 INTERNALVAR_MAKE_VALUE,
1902
1903 /* The internal variable holds a GDB internal convenience function. */
1904 INTERNALVAR_FUNCTION,
1905
1906 /* The variable holds an integer value. */
1907 INTERNALVAR_INTEGER,
1908
1909 /* The variable holds a GDB-provided string. */
1910 INTERNALVAR_STRING,
1911 };
1912
1913 union internalvar_data
1914 {
1915 /* A value object used with INTERNALVAR_VALUE. */
1916 struct value *value;
1917
1918 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1919 struct
1920 {
1921 /* The functions to call. */
1922 const struct internalvar_funcs *functions;
1923
1924 /* The function's user-data. */
1925 void *data;
1926 } make_value;
1927
1928 /* The internal function used with INTERNALVAR_FUNCTION. */
1929 struct
1930 {
1931 struct internal_function *function;
1932 /* True if this is the canonical name for the function. */
1933 int canonical;
1934 } fn;
1935
1936 /* An integer value used with INTERNALVAR_INTEGER. */
1937 struct
1938 {
1939 /* If type is non-NULL, it will be used as the type to generate
1940 a value for this internal variable. If type is NULL, a default
1941 integer type for the architecture is used. */
1942 struct type *type;
1943 LONGEST val;
1944 } integer;
1945
1946 /* A string value used with INTERNALVAR_STRING. */
1947 char *string;
1948 };
1949
1950 /* Internal variables. These are variables within the debugger
1951 that hold values assigned by debugger commands.
1952 The user refers to them with a '$' prefix
1953 that does not appear in the variable names stored internally. */
1954
1955 struct internalvar
1956 {
1957 struct internalvar *next;
1958 char *name;
1959
1960 /* We support various different kinds of content of an internal variable.
1961 enum internalvar_kind specifies the kind, and union internalvar_data
1962 provides the data associated with this particular kind. */
1963
1964 enum internalvar_kind kind;
1965
1966 union internalvar_data u;
1967 };
1968
1969 static struct internalvar *internalvars;
1970
1971 /* If the variable does not already exist create it and give it the
1972 value given. If no value is given then the default is zero. */
1973 static void
1974 init_if_undefined_command (const char* args, int from_tty)
1975 {
1976 struct internalvar* intvar;
1977
1978 /* Parse the expression - this is taken from set_command(). */
1979 expression_up expr = parse_expression (args);
1980
1981 /* Validate the expression.
1982 Was the expression an assignment?
1983 Or even an expression at all? */
1984 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
1985 error (_("Init-if-undefined requires an assignment expression."));
1986
1987 /* Extract the variable from the parsed expression.
1988 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1989 if (expr->elts[1].opcode != OP_INTERNALVAR)
1990 error (_("The first parameter to init-if-undefined "
1991 "should be a GDB variable."));
1992 intvar = expr->elts[2].internalvar;
1993
1994 /* Only evaluate the expression if the lvalue is void.
1995 This may still fail if the expression is invalid. */
1996 if (intvar->kind == INTERNALVAR_VOID)
1997 evaluate_expression (expr.get ());
1998 }
1999
2000
2001 /* Look up an internal variable with name NAME. NAME should not
2002 normally include a dollar sign.
2003
2004 If the specified internal variable does not exist,
2005 the return value is NULL. */
2006
2007 struct internalvar *
2008 lookup_only_internalvar (const char *name)
2009 {
2010 struct internalvar *var;
2011
2012 for (var = internalvars; var; var = var->next)
2013 if (strcmp (var->name, name) == 0)
2014 return var;
2015
2016 return NULL;
2017 }
2018
2019 /* Complete NAME by comparing it to the names of internal
2020 variables. */
2021
2022 void
2023 complete_internalvar (completion_tracker &tracker, const char *name)
2024 {
2025 struct internalvar *var;
2026 int len;
2027
2028 len = strlen (name);
2029
2030 for (var = internalvars; var; var = var->next)
2031 if (strncmp (var->name, name, len) == 0)
2032 tracker.add_completion (make_unique_xstrdup (var->name));
2033 }
2034
2035 /* Create an internal variable with name NAME and with a void value.
2036 NAME should not normally include a dollar sign. */
2037
2038 struct internalvar *
2039 create_internalvar (const char *name)
2040 {
2041 struct internalvar *var = XNEW (struct internalvar);
2042
2043 var->name = xstrdup (name);
2044 var->kind = INTERNALVAR_VOID;
2045 var->next = internalvars;
2046 internalvars = var;
2047 return var;
2048 }
2049
2050 /* Create an internal variable with name NAME and register FUN as the
2051 function that value_of_internalvar uses to create a value whenever
2052 this variable is referenced. NAME should not normally include a
2053 dollar sign. DATA is passed uninterpreted to FUN when it is
2054 called. CLEANUP, if not NULL, is called when the internal variable
2055 is destroyed. It is passed DATA as its only argument. */
2056
2057 struct internalvar *
2058 create_internalvar_type_lazy (const char *name,
2059 const struct internalvar_funcs *funcs,
2060 void *data)
2061 {
2062 struct internalvar *var = create_internalvar (name);
2063
2064 var->kind = INTERNALVAR_MAKE_VALUE;
2065 var->u.make_value.functions = funcs;
2066 var->u.make_value.data = data;
2067 return var;
2068 }
2069
2070 /* See documentation in value.h. */
2071
2072 int
2073 compile_internalvar_to_ax (struct internalvar *var,
2074 struct agent_expr *expr,
2075 struct axs_value *value)
2076 {
2077 if (var->kind != INTERNALVAR_MAKE_VALUE
2078 || var->u.make_value.functions->compile_to_ax == NULL)
2079 return 0;
2080
2081 var->u.make_value.functions->compile_to_ax (var, expr, value,
2082 var->u.make_value.data);
2083 return 1;
2084 }
2085
2086 /* Look up an internal variable with name NAME. NAME should not
2087 normally include a dollar sign.
2088
2089 If the specified internal variable does not exist,
2090 one is created, with a void value. */
2091
2092 struct internalvar *
2093 lookup_internalvar (const char *name)
2094 {
2095 struct internalvar *var;
2096
2097 var = lookup_only_internalvar (name);
2098 if (var)
2099 return var;
2100
2101 return create_internalvar (name);
2102 }
2103
2104 /* Return current value of internal variable VAR. For variables that
2105 are not inherently typed, use a value type appropriate for GDBARCH. */
2106
2107 struct value *
2108 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
2109 {
2110 struct value *val;
2111 struct trace_state_variable *tsv;
2112
2113 /* If there is a trace state variable of the same name, assume that
2114 is what we really want to see. */
2115 tsv = find_trace_state_variable (var->name);
2116 if (tsv)
2117 {
2118 tsv->value_known = target_get_trace_state_variable_value (tsv->number,
2119 &(tsv->value));
2120 if (tsv->value_known)
2121 val = value_from_longest (builtin_type (gdbarch)->builtin_int64,
2122 tsv->value);
2123 else
2124 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2125 return val;
2126 }
2127
2128 switch (var->kind)
2129 {
2130 case INTERNALVAR_VOID:
2131 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2132 break;
2133
2134 case INTERNALVAR_FUNCTION:
2135 val = allocate_value (builtin_type (gdbarch)->internal_fn);
2136 break;
2137
2138 case INTERNALVAR_INTEGER:
2139 if (!var->u.integer.type)
2140 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
2141 var->u.integer.val);
2142 else
2143 val = value_from_longest (var->u.integer.type, var->u.integer.val);
2144 break;
2145
2146 case INTERNALVAR_STRING:
2147 val = value_cstring (var->u.string, strlen (var->u.string),
2148 builtin_type (gdbarch)->builtin_char);
2149 break;
2150
2151 case INTERNALVAR_VALUE:
2152 val = value_copy (var->u.value);
2153 if (value_lazy (val))
2154 value_fetch_lazy (val);
2155 break;
2156
2157 case INTERNALVAR_MAKE_VALUE:
2158 val = (*var->u.make_value.functions->make_value) (gdbarch, var,
2159 var->u.make_value.data);
2160 break;
2161
2162 default:
2163 internal_error (__FILE__, __LINE__, _("bad kind"));
2164 }
2165
2166 /* Change the VALUE_LVAL to lval_internalvar so that future operations
2167 on this value go back to affect the original internal variable.
2168
2169 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
2170 no underlying modifiable state in the internal variable.
2171
2172 Likewise, if the variable's value is a computed lvalue, we want
2173 references to it to produce another computed lvalue, where
2174 references and assignments actually operate through the
2175 computed value's functions.
2176
2177 This means that internal variables with computed values
2178 behave a little differently from other internal variables:
2179 assignments to them don't just replace the previous value
2180 altogether. At the moment, this seems like the behavior we
2181 want. */
2182
2183 if (var->kind != INTERNALVAR_MAKE_VALUE
2184 && val->lval != lval_computed)
2185 {
2186 VALUE_LVAL (val) = lval_internalvar;
2187 VALUE_INTERNALVAR (val) = var;
2188 }
2189
2190 return val;
2191 }
2192
2193 int
2194 get_internalvar_integer (struct internalvar *var, LONGEST *result)
2195 {
2196 if (var->kind == INTERNALVAR_INTEGER)
2197 {
2198 *result = var->u.integer.val;
2199 return 1;
2200 }
2201
2202 if (var->kind == INTERNALVAR_VALUE)
2203 {
2204 struct type *type = check_typedef (value_type (var->u.value));
2205
2206 if (type->code () == TYPE_CODE_INT)
2207 {
2208 *result = value_as_long (var->u.value);
2209 return 1;
2210 }
2211 }
2212
2213 return 0;
2214 }
2215
2216 static int
2217 get_internalvar_function (struct internalvar *var,
2218 struct internal_function **result)
2219 {
2220 switch (var->kind)
2221 {
2222 case INTERNALVAR_FUNCTION:
2223 *result = var->u.fn.function;
2224 return 1;
2225
2226 default:
2227 return 0;
2228 }
2229 }
2230
2231 void
2232 set_internalvar_component (struct internalvar *var,
2233 LONGEST offset, LONGEST bitpos,
2234 LONGEST bitsize, struct value *newval)
2235 {
2236 gdb_byte *addr;
2237 struct gdbarch *arch;
2238 int unit_size;
2239
2240 switch (var->kind)
2241 {
2242 case INTERNALVAR_VALUE:
2243 addr = value_contents_writeable (var->u.value);
2244 arch = get_value_arch (var->u.value);
2245 unit_size = gdbarch_addressable_memory_unit_size (arch);
2246
2247 if (bitsize)
2248 modify_field (value_type (var->u.value), addr + offset,
2249 value_as_long (newval), bitpos, bitsize);
2250 else
2251 memcpy (addr + offset * unit_size, value_contents (newval),
2252 TYPE_LENGTH (value_type (newval)));
2253 break;
2254
2255 default:
2256 /* We can never get a component of any other kind. */
2257 internal_error (__FILE__, __LINE__, _("set_internalvar_component"));
2258 }
2259 }
2260
2261 void
2262 set_internalvar (struct internalvar *var, struct value *val)
2263 {
2264 enum internalvar_kind new_kind;
2265 union internalvar_data new_data = { 0 };
2266
2267 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
2268 error (_("Cannot overwrite convenience function %s"), var->name);
2269
2270 /* Prepare new contents. */
2271 switch (check_typedef (value_type (val))->code ())
2272 {
2273 case TYPE_CODE_VOID:
2274 new_kind = INTERNALVAR_VOID;
2275 break;
2276
2277 case TYPE_CODE_INTERNAL_FUNCTION:
2278 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2279 new_kind = INTERNALVAR_FUNCTION;
2280 get_internalvar_function (VALUE_INTERNALVAR (val),
2281 &new_data.fn.function);
2282 /* Copies created here are never canonical. */
2283 break;
2284
2285 default:
2286 new_kind = INTERNALVAR_VALUE;
2287 struct value *copy = value_copy (val);
2288 copy->modifiable = 1;
2289
2290 /* Force the value to be fetched from the target now, to avoid problems
2291 later when this internalvar is referenced and the target is gone or
2292 has changed. */
2293 if (value_lazy (copy))
2294 value_fetch_lazy (copy);
2295
2296 /* Release the value from the value chain to prevent it from being
2297 deleted by free_all_values. From here on this function should not
2298 call error () until new_data is installed into the var->u to avoid
2299 leaking memory. */
2300 new_data.value = release_value (copy).release ();
2301
2302 /* Internal variables which are created from values with a dynamic
2303 location don't need the location property of the origin anymore.
2304 The resolved dynamic location is used prior then any other address
2305 when accessing the value.
2306 If we keep it, we would still refer to the origin value.
2307 Remove the location property in case it exist. */
2308 value_type (new_data.value)->remove_dyn_prop (DYN_PROP_DATA_LOCATION);
2309
2310 break;
2311 }
2312
2313 /* Clean up old contents. */
2314 clear_internalvar (var);
2315
2316 /* Switch over. */
2317 var->kind = new_kind;
2318 var->u = new_data;
2319 /* End code which must not call error(). */
2320 }
2321
2322 void
2323 set_internalvar_integer (struct internalvar *var, LONGEST l)
2324 {
2325 /* Clean up old contents. */
2326 clear_internalvar (var);
2327
2328 var->kind = INTERNALVAR_INTEGER;
2329 var->u.integer.type = NULL;
2330 var->u.integer.val = l;
2331 }
2332
2333 void
2334 set_internalvar_string (struct internalvar *var, const char *string)
2335 {
2336 /* Clean up old contents. */
2337 clear_internalvar (var);
2338
2339 var->kind = INTERNALVAR_STRING;
2340 var->u.string = xstrdup (string);
2341 }
2342
2343 static void
2344 set_internalvar_function (struct internalvar *var, struct internal_function *f)
2345 {
2346 /* Clean up old contents. */
2347 clear_internalvar (var);
2348
2349 var->kind = INTERNALVAR_FUNCTION;
2350 var->u.fn.function = f;
2351 var->u.fn.canonical = 1;
2352 /* Variables installed here are always the canonical version. */
2353 }
2354
2355 void
2356 clear_internalvar (struct internalvar *var)
2357 {
2358 /* Clean up old contents. */
2359 switch (var->kind)
2360 {
2361 case INTERNALVAR_VALUE:
2362 value_decref (var->u.value);
2363 break;
2364
2365 case INTERNALVAR_STRING:
2366 xfree (var->u.string);
2367 break;
2368
2369 case INTERNALVAR_MAKE_VALUE:
2370 if (var->u.make_value.functions->destroy != NULL)
2371 var->u.make_value.functions->destroy (var->u.make_value.data);
2372 break;
2373
2374 default:
2375 break;
2376 }
2377
2378 /* Reset to void kind. */
2379 var->kind = INTERNALVAR_VOID;
2380 }
2381
2382 const char *
2383 internalvar_name (const struct internalvar *var)
2384 {
2385 return var->name;
2386 }
2387
2388 static struct internal_function *
2389 create_internal_function (const char *name,
2390 internal_function_fn handler, void *cookie)
2391 {
2392 struct internal_function *ifn = XNEW (struct internal_function);
2393
2394 ifn->name = xstrdup (name);
2395 ifn->handler = handler;
2396 ifn->cookie = cookie;
2397 return ifn;
2398 }
2399
2400 char *
2401 value_internal_function_name (struct value *val)
2402 {
2403 struct internal_function *ifn;
2404 int result;
2405
2406 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2407 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
2408 gdb_assert (result);
2409
2410 return ifn->name;
2411 }
2412
2413 struct value *
2414 call_internal_function (struct gdbarch *gdbarch,
2415 const struct language_defn *language,
2416 struct value *func, int argc, struct value **argv)
2417 {
2418 struct internal_function *ifn;
2419 int result;
2420
2421 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
2422 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
2423 gdb_assert (result);
2424
2425 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
2426 }
2427
2428 /* The 'function' command. This does nothing -- it is just a
2429 placeholder to let "help function NAME" work. This is also used as
2430 the implementation of the sub-command that is created when
2431 registering an internal function. */
2432 static void
2433 function_command (const char *command, int from_tty)
2434 {
2435 /* Do nothing. */
2436 }
2437
2438 /* Helper function that does the work for add_internal_function. */
2439
2440 static struct cmd_list_element *
2441 do_add_internal_function (const char *name, const char *doc,
2442 internal_function_fn handler, void *cookie)
2443 {
2444 struct internal_function *ifn;
2445 struct internalvar *var = lookup_internalvar (name);
2446
2447 ifn = create_internal_function (name, handler, cookie);
2448 set_internalvar_function (var, ifn);
2449
2450 return add_cmd (name, no_class, function_command, doc, &functionlist);
2451 }
2452
2453 /* See value.h. */
2454
2455 void
2456 add_internal_function (const char *name, const char *doc,
2457 internal_function_fn handler, void *cookie)
2458 {
2459 do_add_internal_function (name, doc, handler, cookie);
2460 }
2461
2462 /* See value.h. */
2463
2464 void
2465 add_internal_function (gdb::unique_xmalloc_ptr<char> &&name,
2466 gdb::unique_xmalloc_ptr<char> &&doc,
2467 internal_function_fn handler, void *cookie)
2468 {
2469 struct cmd_list_element *cmd
2470 = do_add_internal_function (name.get (), doc.get (), handler, cookie);
2471 doc.release ();
2472 cmd->doc_allocated = 1;
2473 name.release ();
2474 cmd->name_allocated = 1;
2475 }
2476
2477 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
2478 prevent cycles / duplicates. */
2479
2480 void
2481 preserve_one_value (struct value *value, struct objfile *objfile,
2482 htab_t copied_types)
2483 {
2484 if (TYPE_OBJFILE (value->type) == objfile)
2485 value->type = copy_type_recursive (objfile, value->type, copied_types);
2486
2487 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
2488 value->enclosing_type = copy_type_recursive (objfile,
2489 value->enclosing_type,
2490 copied_types);
2491 }
2492
2493 /* Likewise for internal variable VAR. */
2494
2495 static void
2496 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
2497 htab_t copied_types)
2498 {
2499 switch (var->kind)
2500 {
2501 case INTERNALVAR_INTEGER:
2502 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
2503 var->u.integer.type
2504 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
2505 break;
2506
2507 case INTERNALVAR_VALUE:
2508 preserve_one_value (var->u.value, objfile, copied_types);
2509 break;
2510 }
2511 }
2512
2513 /* Update the internal variables and value history when OBJFILE is
2514 discarded; we must copy the types out of the objfile. New global types
2515 will be created for every convenience variable which currently points to
2516 this objfile's types, and the convenience variables will be adjusted to
2517 use the new global types. */
2518
2519 void
2520 preserve_values (struct objfile *objfile)
2521 {
2522 struct internalvar *var;
2523
2524 /* Create the hash table. We allocate on the objfile's obstack, since
2525 it is soon to be deleted. */
2526 htab_up copied_types = create_copied_types_hash (objfile);
2527
2528 for (const value_ref_ptr &item : value_history)
2529 preserve_one_value (item.get (), objfile, copied_types.get ());
2530
2531 for (var = internalvars; var; var = var->next)
2532 preserve_one_internalvar (var, objfile, copied_types.get ());
2533
2534 preserve_ext_lang_values (objfile, copied_types.get ());
2535 }
2536
2537 static void
2538 show_convenience (const char *ignore, int from_tty)
2539 {
2540 struct gdbarch *gdbarch = get_current_arch ();
2541 struct internalvar *var;
2542 int varseen = 0;
2543 struct value_print_options opts;
2544
2545 get_user_print_options (&opts);
2546 for (var = internalvars; var; var = var->next)
2547 {
2548
2549 if (!varseen)
2550 {
2551 varseen = 1;
2552 }
2553 printf_filtered (("$%s = "), var->name);
2554
2555 try
2556 {
2557 struct value *val;
2558
2559 val = value_of_internalvar (gdbarch, var);
2560 value_print (val, gdb_stdout, &opts);
2561 }
2562 catch (const gdb_exception_error &ex)
2563 {
2564 fprintf_styled (gdb_stdout, metadata_style.style (),
2565 _("<error: %s>"), ex.what ());
2566 }
2567
2568 printf_filtered (("\n"));
2569 }
2570 if (!varseen)
2571 {
2572 /* This text does not mention convenience functions on purpose.
2573 The user can't create them except via Python, and if Python support
2574 is installed this message will never be printed ($_streq will
2575 exist). */
2576 printf_unfiltered (_("No debugger convenience variables now defined.\n"
2577 "Convenience variables have "
2578 "names starting with \"$\";\n"
2579 "use \"set\" as in \"set "
2580 "$foo = 5\" to define them.\n"));
2581 }
2582 }
2583 \f
2584
2585 /* See value.h. */
2586
2587 struct value *
2588 value_from_xmethod (xmethod_worker_up &&worker)
2589 {
2590 struct value *v;
2591
2592 v = allocate_value (builtin_type (target_gdbarch ())->xmethod);
2593 v->lval = lval_xcallable;
2594 v->location.xm_worker = worker.release ();
2595 v->modifiable = 0;
2596
2597 return v;
2598 }
2599
2600 /* Return the type of the result of TYPE_CODE_XMETHOD value METHOD. */
2601
2602 struct type *
2603 result_type_of_xmethod (struct value *method, gdb::array_view<value *> argv)
2604 {
2605 gdb_assert (value_type (method)->code () == TYPE_CODE_XMETHOD
2606 && method->lval == lval_xcallable && !argv.empty ());
2607
2608 return method->location.xm_worker->get_result_type (argv[0], argv.slice (1));
2609 }
2610
2611 /* Call the xmethod corresponding to the TYPE_CODE_XMETHOD value METHOD. */
2612
2613 struct value *
2614 call_xmethod (struct value *method, gdb::array_view<value *> argv)
2615 {
2616 gdb_assert (value_type (method)->code () == TYPE_CODE_XMETHOD
2617 && method->lval == lval_xcallable && !argv.empty ());
2618
2619 return method->location.xm_worker->invoke (argv[0], argv.slice (1));
2620 }
2621 \f
2622 /* Extract a value as a C number (either long or double).
2623 Knows how to convert fixed values to double, or
2624 floating values to long.
2625 Does not deallocate the value. */
2626
2627 LONGEST
2628 value_as_long (struct value *val)
2629 {
2630 /* This coerces arrays and functions, which is necessary (e.g.
2631 in disassemble_command). It also dereferences references, which
2632 I suspect is the most logical thing to do. */
2633 val = coerce_array (val);
2634 return unpack_long (value_type (val), value_contents (val));
2635 }
2636
2637 /* Extract a value as a C pointer. Does not deallocate the value.
2638 Note that val's type may not actually be a pointer; value_as_long
2639 handles all the cases. */
2640 CORE_ADDR
2641 value_as_address (struct value *val)
2642 {
2643 struct gdbarch *gdbarch = get_type_arch (value_type (val));
2644
2645 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2646 whether we want this to be true eventually. */
2647 #if 0
2648 /* gdbarch_addr_bits_remove is wrong if we are being called for a
2649 non-address (e.g. argument to "signal", "info break", etc.), or
2650 for pointers to char, in which the low bits *are* significant. */
2651 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
2652 #else
2653
2654 /* There are several targets (IA-64, PowerPC, and others) which
2655 don't represent pointers to functions as simply the address of
2656 the function's entry point. For example, on the IA-64, a
2657 function pointer points to a two-word descriptor, generated by
2658 the linker, which contains the function's entry point, and the
2659 value the IA-64 "global pointer" register should have --- to
2660 support position-independent code. The linker generates
2661 descriptors only for those functions whose addresses are taken.
2662
2663 On such targets, it's difficult for GDB to convert an arbitrary
2664 function address into a function pointer; it has to either find
2665 an existing descriptor for that function, or call malloc and
2666 build its own. On some targets, it is impossible for GDB to
2667 build a descriptor at all: the descriptor must contain a jump
2668 instruction; data memory cannot be executed; and code memory
2669 cannot be modified.
2670
2671 Upon entry to this function, if VAL is a value of type `function'
2672 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2673 value_address (val) is the address of the function. This is what
2674 you'll get if you evaluate an expression like `main'. The call
2675 to COERCE_ARRAY below actually does all the usual unary
2676 conversions, which includes converting values of type `function'
2677 to `pointer to function'. This is the challenging conversion
2678 discussed above. Then, `unpack_long' will convert that pointer
2679 back into an address.
2680
2681 So, suppose the user types `disassemble foo' on an architecture
2682 with a strange function pointer representation, on which GDB
2683 cannot build its own descriptors, and suppose further that `foo'
2684 has no linker-built descriptor. The address->pointer conversion
2685 will signal an error and prevent the command from running, even
2686 though the next step would have been to convert the pointer
2687 directly back into the same address.
2688
2689 The following shortcut avoids this whole mess. If VAL is a
2690 function, just return its address directly. */
2691 if (value_type (val)->code () == TYPE_CODE_FUNC
2692 || value_type (val)->code () == TYPE_CODE_METHOD)
2693 return value_address (val);
2694
2695 val = coerce_array (val);
2696
2697 /* Some architectures (e.g. Harvard), map instruction and data
2698 addresses onto a single large unified address space. For
2699 instance: An architecture may consider a large integer in the
2700 range 0x10000000 .. 0x1000ffff to already represent a data
2701 addresses (hence not need a pointer to address conversion) while
2702 a small integer would still need to be converted integer to
2703 pointer to address. Just assume such architectures handle all
2704 integer conversions in a single function. */
2705
2706 /* JimB writes:
2707
2708 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2709 must admonish GDB hackers to make sure its behavior matches the
2710 compiler's, whenever possible.
2711
2712 In general, I think GDB should evaluate expressions the same way
2713 the compiler does. When the user copies an expression out of
2714 their source code and hands it to a `print' command, they should
2715 get the same value the compiler would have computed. Any
2716 deviation from this rule can cause major confusion and annoyance,
2717 and needs to be justified carefully. In other words, GDB doesn't
2718 really have the freedom to do these conversions in clever and
2719 useful ways.
2720
2721 AndrewC pointed out that users aren't complaining about how GDB
2722 casts integers to pointers; they are complaining that they can't
2723 take an address from a disassembly listing and give it to `x/i'.
2724 This is certainly important.
2725
2726 Adding an architecture method like integer_to_address() certainly
2727 makes it possible for GDB to "get it right" in all circumstances
2728 --- the target has complete control over how things get done, so
2729 people can Do The Right Thing for their target without breaking
2730 anyone else. The standard doesn't specify how integers get
2731 converted to pointers; usually, the ABI doesn't either, but
2732 ABI-specific code is a more reasonable place to handle it. */
2733
2734 if (value_type (val)->code () != TYPE_CODE_PTR
2735 && !TYPE_IS_REFERENCE (value_type (val))
2736 && gdbarch_integer_to_address_p (gdbarch))
2737 return gdbarch_integer_to_address (gdbarch, value_type (val),
2738 value_contents (val));
2739
2740 return unpack_long (value_type (val), value_contents (val));
2741 #endif
2742 }
2743 \f
2744 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2745 as a long, or as a double, assuming the raw data is described
2746 by type TYPE. Knows how to convert different sizes of values
2747 and can convert between fixed and floating point. We don't assume
2748 any alignment for the raw data. Return value is in host byte order.
2749
2750 If you want functions and arrays to be coerced to pointers, and
2751 references to be dereferenced, call value_as_long() instead.
2752
2753 C++: It is assumed that the front-end has taken care of
2754 all matters concerning pointers to members. A pointer
2755 to member which reaches here is considered to be equivalent
2756 to an INT (or some size). After all, it is only an offset. */
2757
2758 LONGEST
2759 unpack_long (struct type *type, const gdb_byte *valaddr)
2760 {
2761 if (is_fixed_point_type (type))
2762 type = fixed_point_type_base_type (type);
2763
2764 enum bfd_endian byte_order = type_byte_order (type);
2765 enum type_code code = type->code ();
2766 int len = TYPE_LENGTH (type);
2767 int nosign = type->is_unsigned ();
2768
2769 switch (code)
2770 {
2771 case TYPE_CODE_TYPEDEF:
2772 return unpack_long (check_typedef (type), valaddr);
2773 case TYPE_CODE_ENUM:
2774 case TYPE_CODE_FLAGS:
2775 case TYPE_CODE_BOOL:
2776 case TYPE_CODE_INT:
2777 case TYPE_CODE_CHAR:
2778 case TYPE_CODE_RANGE:
2779 case TYPE_CODE_MEMBERPTR:
2780 {
2781 LONGEST result;
2782
2783 if (type->bit_size_differs_p ())
2784 {
2785 unsigned bit_off = type->bit_offset ();
2786 unsigned bit_size = type->bit_size ();
2787 if (bit_size == 0)
2788 {
2789 /* unpack_bits_as_long doesn't handle this case the
2790 way we'd like, so handle it here. */
2791 result = 0;
2792 }
2793 else
2794 result = unpack_bits_as_long (type, valaddr, bit_off, bit_size);
2795 }
2796 else
2797 {
2798 if (nosign)
2799 result = extract_unsigned_integer (valaddr, len, byte_order);
2800 else
2801 result = extract_signed_integer (valaddr, len, byte_order);
2802 }
2803 if (code == TYPE_CODE_RANGE)
2804 result += type->bounds ()->bias;
2805 return result;
2806 }
2807
2808 case TYPE_CODE_FLT:
2809 case TYPE_CODE_DECFLOAT:
2810 return target_float_to_longest (valaddr, type);
2811
2812 case TYPE_CODE_FIXED_POINT:
2813 {
2814 gdb_mpq vq;
2815 vq.read_fixed_point (valaddr, len, byte_order, nosign,
2816 fixed_point_scaling_factor (type));
2817
2818 gdb_mpz vz;
2819 mpz_tdiv_q (vz.val, mpq_numref (vq.val), mpq_denref (vq.val));
2820 return vz.as_integer<LONGEST> ();
2821 }
2822
2823 case TYPE_CODE_PTR:
2824 case TYPE_CODE_REF:
2825 case TYPE_CODE_RVALUE_REF:
2826 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2827 whether we want this to be true eventually. */
2828 return extract_typed_address (valaddr, type);
2829
2830 default:
2831 error (_("Value can't be converted to integer."));
2832 }
2833 }
2834
2835 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2836 as a CORE_ADDR, assuming the raw data is described by type TYPE.
2837 We don't assume any alignment for the raw data. Return value is in
2838 host byte order.
2839
2840 If you want functions and arrays to be coerced to pointers, and
2841 references to be dereferenced, call value_as_address() instead.
2842
2843 C++: It is assumed that the front-end has taken care of
2844 all matters concerning pointers to members. A pointer
2845 to member which reaches here is considered to be equivalent
2846 to an INT (or some size). After all, it is only an offset. */
2847
2848 CORE_ADDR
2849 unpack_pointer (struct type *type, const gdb_byte *valaddr)
2850 {
2851 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2852 whether we want this to be true eventually. */
2853 return unpack_long (type, valaddr);
2854 }
2855
2856 bool
2857 is_floating_value (struct value *val)
2858 {
2859 struct type *type = check_typedef (value_type (val));
2860
2861 if (is_floating_type (type))
2862 {
2863 if (!target_float_is_valid (value_contents (val), type))
2864 error (_("Invalid floating value found in program."));
2865 return true;
2866 }
2867
2868 return false;
2869 }
2870
2871 \f
2872 /* Get the value of the FIELDNO'th field (which must be static) of
2873 TYPE. */
2874
2875 struct value *
2876 value_static_field (struct type *type, int fieldno)
2877 {
2878 struct value *retval;
2879
2880 switch (TYPE_FIELD_LOC_KIND (type, fieldno))
2881 {
2882 case FIELD_LOC_KIND_PHYSADDR:
2883 retval = value_at_lazy (type->field (fieldno).type (),
2884 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
2885 break;
2886 case FIELD_LOC_KIND_PHYSNAME:
2887 {
2888 const char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
2889 /* TYPE_FIELD_NAME (type, fieldno); */
2890 struct block_symbol sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
2891
2892 if (sym.symbol == NULL)
2893 {
2894 /* With some compilers, e.g. HP aCC, static data members are
2895 reported as non-debuggable symbols. */
2896 struct bound_minimal_symbol msym
2897 = lookup_minimal_symbol (phys_name, NULL, NULL);
2898 struct type *field_type = type->field (fieldno).type ();
2899
2900 if (!msym.minsym)
2901 retval = allocate_optimized_out_value (field_type);
2902 else
2903 retval = value_at_lazy (field_type, BMSYMBOL_VALUE_ADDRESS (msym));
2904 }
2905 else
2906 retval = value_of_variable (sym.symbol, sym.block);
2907 break;
2908 }
2909 default:
2910 gdb_assert_not_reached ("unexpected field location kind");
2911 }
2912
2913 return retval;
2914 }
2915
2916 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
2917 You have to be careful here, since the size of the data area for the value
2918 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
2919 than the old enclosing type, you have to allocate more space for the
2920 data. */
2921
2922 void
2923 set_value_enclosing_type (struct value *val, struct type *new_encl_type)
2924 {
2925 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
2926 {
2927 check_type_length_before_alloc (new_encl_type);
2928 val->contents
2929 .reset ((gdb_byte *) xrealloc (val->contents.release (),
2930 TYPE_LENGTH (new_encl_type)));
2931 }
2932
2933 val->enclosing_type = new_encl_type;
2934 }
2935
2936 /* Given a value ARG1 (offset by OFFSET bytes)
2937 of a struct or union type ARG_TYPE,
2938 extract and return the value of one of its (non-static) fields.
2939 FIELDNO says which field. */
2940
2941 struct value *
2942 value_primitive_field (struct value *arg1, LONGEST offset,
2943 int fieldno, struct type *arg_type)
2944 {
2945 struct value *v;
2946 struct type *type;
2947 struct gdbarch *arch = get_value_arch (arg1);
2948 int unit_size = gdbarch_addressable_memory_unit_size (arch);
2949
2950 arg_type = check_typedef (arg_type);
2951 type = arg_type->field (fieldno).type ();
2952
2953 /* Call check_typedef on our type to make sure that, if TYPE
2954 is a TYPE_CODE_TYPEDEF, its length is set to the length
2955 of the target type instead of zero. However, we do not
2956 replace the typedef type by the target type, because we want
2957 to keep the typedef in order to be able to print the type
2958 description correctly. */
2959 check_typedef (type);
2960
2961 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
2962 {
2963 /* Handle packed fields.
2964
2965 Create a new value for the bitfield, with bitpos and bitsize
2966 set. If possible, arrange offset and bitpos so that we can
2967 do a single aligned read of the size of the containing type.
2968 Otherwise, adjust offset to the byte containing the first
2969 bit. Assume that the address, offset, and embedded offset
2970 are sufficiently aligned. */
2971
2972 LONGEST bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
2973 LONGEST container_bitsize = TYPE_LENGTH (type) * 8;
2974
2975 v = allocate_value_lazy (type);
2976 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
2977 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
2978 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
2979 v->bitpos = bitpos % container_bitsize;
2980 else
2981 v->bitpos = bitpos % 8;
2982 v->offset = (value_embedded_offset (arg1)
2983 + offset
2984 + (bitpos - v->bitpos) / 8);
2985 set_value_parent (v, arg1);
2986 if (!value_lazy (arg1))
2987 value_fetch_lazy (v);
2988 }
2989 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
2990 {
2991 /* This field is actually a base subobject, so preserve the
2992 entire object's contents for later references to virtual
2993 bases, etc. */
2994 LONGEST boffset;
2995
2996 /* Lazy register values with offsets are not supported. */
2997 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
2998 value_fetch_lazy (arg1);
2999
3000 /* We special case virtual inheritance here because this
3001 requires access to the contents, which we would rather avoid
3002 for references to ordinary fields of unavailable values. */
3003 if (BASETYPE_VIA_VIRTUAL (arg_type, fieldno))
3004 boffset = baseclass_offset (arg_type, fieldno,
3005 value_contents (arg1),
3006 value_embedded_offset (arg1),
3007 value_address (arg1),
3008 arg1);
3009 else
3010 boffset = TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
3011
3012 if (value_lazy (arg1))
3013 v = allocate_value_lazy (value_enclosing_type (arg1));
3014 else
3015 {
3016 v = allocate_value (value_enclosing_type (arg1));
3017 value_contents_copy_raw (v, 0, arg1, 0,
3018 TYPE_LENGTH (value_enclosing_type (arg1)));
3019 }
3020 v->type = type;
3021 v->offset = value_offset (arg1);
3022 v->embedded_offset = offset + value_embedded_offset (arg1) + boffset;
3023 }
3024 else if (NULL != TYPE_DATA_LOCATION (type))
3025 {
3026 /* Field is a dynamic data member. */
3027
3028 gdb_assert (0 == offset);
3029 /* We expect an already resolved data location. */
3030 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (type));
3031 /* For dynamic data types defer memory allocation
3032 until we actual access the value. */
3033 v = allocate_value_lazy (type);
3034 }
3035 else
3036 {
3037 /* Plain old data member */
3038 offset += (TYPE_FIELD_BITPOS (arg_type, fieldno)
3039 / (HOST_CHAR_BIT * unit_size));
3040
3041 /* Lazy register values with offsets are not supported. */
3042 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3043 value_fetch_lazy (arg1);
3044
3045 if (value_lazy (arg1))
3046 v = allocate_value_lazy (type);
3047 else
3048 {
3049 v = allocate_value (type);
3050 value_contents_copy_raw (v, value_embedded_offset (v),
3051 arg1, value_embedded_offset (arg1) + offset,
3052 type_length_units (type));
3053 }
3054 v->offset = (value_offset (arg1) + offset
3055 + value_embedded_offset (arg1));
3056 }
3057 set_value_component_location (v, arg1);
3058 return v;
3059 }
3060
3061 /* Given a value ARG1 of a struct or union type,
3062 extract and return the value of one of its (non-static) fields.
3063 FIELDNO says which field. */
3064
3065 struct value *
3066 value_field (struct value *arg1, int fieldno)
3067 {
3068 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
3069 }
3070
3071 /* Return a non-virtual function as a value.
3072 F is the list of member functions which contains the desired method.
3073 J is an index into F which provides the desired method.
3074
3075 We only use the symbol for its address, so be happy with either a
3076 full symbol or a minimal symbol. */
3077
3078 struct value *
3079 value_fn_field (struct value **arg1p, struct fn_field *f,
3080 int j, struct type *type,
3081 LONGEST offset)
3082 {
3083 struct value *v;
3084 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
3085 const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
3086 struct symbol *sym;
3087 struct bound_minimal_symbol msym;
3088
3089 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0).symbol;
3090 if (sym != NULL)
3091 {
3092 memset (&msym, 0, sizeof (msym));
3093 }
3094 else
3095 {
3096 gdb_assert (sym == NULL);
3097 msym = lookup_bound_minimal_symbol (physname);
3098 if (msym.minsym == NULL)
3099 return NULL;
3100 }
3101
3102 v = allocate_value (ftype);
3103 VALUE_LVAL (v) = lval_memory;
3104 if (sym)
3105 {
3106 set_value_address (v, BLOCK_ENTRY_PC (SYMBOL_BLOCK_VALUE (sym)));
3107 }
3108 else
3109 {
3110 /* The minimal symbol might point to a function descriptor;
3111 resolve it to the actual code address instead. */
3112 struct objfile *objfile = msym.objfile;
3113 struct gdbarch *gdbarch = objfile->arch ();
3114
3115 set_value_address (v,
3116 gdbarch_convert_from_func_ptr_addr
3117 (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), current_top_target ()));
3118 }
3119
3120 if (arg1p)
3121 {
3122 if (type != value_type (*arg1p))
3123 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
3124 value_addr (*arg1p)));
3125
3126 /* Move the `this' pointer according to the offset.
3127 VALUE_OFFSET (*arg1p) += offset; */
3128 }
3129
3130 return v;
3131 }
3132
3133 \f
3134
3135 /* See value.h. */
3136
3137 LONGEST
3138 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
3139 LONGEST bitpos, LONGEST bitsize)
3140 {
3141 enum bfd_endian byte_order = type_byte_order (field_type);
3142 ULONGEST val;
3143 ULONGEST valmask;
3144 int lsbcount;
3145 LONGEST bytes_read;
3146 LONGEST read_offset;
3147
3148 /* Read the minimum number of bytes required; there may not be
3149 enough bytes to read an entire ULONGEST. */
3150 field_type = check_typedef (field_type);
3151 if (bitsize)
3152 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
3153 else
3154 {
3155 bytes_read = TYPE_LENGTH (field_type);
3156 bitsize = 8 * bytes_read;
3157 }
3158
3159 read_offset = bitpos / 8;
3160
3161 val = extract_unsigned_integer (valaddr + read_offset,
3162 bytes_read, byte_order);
3163
3164 /* Extract bits. See comment above. */
3165
3166 if (byte_order == BFD_ENDIAN_BIG)
3167 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
3168 else
3169 lsbcount = (bitpos % 8);
3170 val >>= lsbcount;
3171
3172 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
3173 If the field is signed, and is negative, then sign extend. */
3174
3175 if (bitsize < 8 * (int) sizeof (val))
3176 {
3177 valmask = (((ULONGEST) 1) << bitsize) - 1;
3178 val &= valmask;
3179 if (!field_type->is_unsigned ())
3180 {
3181 if (val & (valmask ^ (valmask >> 1)))
3182 {
3183 val |= ~valmask;
3184 }
3185 }
3186 }
3187
3188 return val;
3189 }
3190
3191 /* Unpack a field FIELDNO of the specified TYPE, from the object at
3192 VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
3193 ORIGINAL_VALUE, which must not be NULL. See
3194 unpack_value_bits_as_long for more details. */
3195
3196 int
3197 unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
3198 LONGEST embedded_offset, int fieldno,
3199 const struct value *val, LONGEST *result)
3200 {
3201 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3202 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3203 struct type *field_type = type->field (fieldno).type ();
3204 int bit_offset;
3205
3206 gdb_assert (val != NULL);
3207
3208 bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3209 if (value_bits_any_optimized_out (val, bit_offset, bitsize)
3210 || !value_bits_available (val, bit_offset, bitsize))
3211 return 0;
3212
3213 *result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3214 bitpos, bitsize);
3215 return 1;
3216 }
3217
3218 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous
3219 object at VALADDR. See unpack_bits_as_long for more details. */
3220
3221 LONGEST
3222 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
3223 {
3224 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3225 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3226 struct type *field_type = type->field (fieldno).type ();
3227
3228 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
3229 }
3230
3231 /* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
3232 VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
3233 the contents in DEST_VAL, zero or sign extending if the type of
3234 DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
3235 VAL. If the VAL's contents required to extract the bitfield from
3236 are unavailable/optimized out, DEST_VAL is correspondingly
3237 marked unavailable/optimized out. */
3238
3239 void
3240 unpack_value_bitfield (struct value *dest_val,
3241 LONGEST bitpos, LONGEST bitsize,
3242 const gdb_byte *valaddr, LONGEST embedded_offset,
3243 const struct value *val)
3244 {
3245 enum bfd_endian byte_order;
3246 int src_bit_offset;
3247 int dst_bit_offset;
3248 struct type *field_type = value_type (dest_val);
3249
3250 byte_order = type_byte_order (field_type);
3251
3252 /* First, unpack and sign extend the bitfield as if it was wholly
3253 valid. Optimized out/unavailable bits are read as zero, but
3254 that's OK, as they'll end up marked below. If the VAL is
3255 wholly-invalid we may have skipped allocating its contents,
3256 though. See allocate_optimized_out_value. */
3257 if (valaddr != NULL)
3258 {
3259 LONGEST num;
3260
3261 num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3262 bitpos, bitsize);
3263 store_signed_integer (value_contents_raw (dest_val),
3264 TYPE_LENGTH (field_type), byte_order, num);
3265 }
3266
3267 /* Now copy the optimized out / unavailability ranges to the right
3268 bits. */
3269 src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3270 if (byte_order == BFD_ENDIAN_BIG)
3271 dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
3272 else
3273 dst_bit_offset = 0;
3274 value_ranges_copy_adjusted (dest_val, dst_bit_offset,
3275 val, src_bit_offset, bitsize);
3276 }
3277
3278 /* Return a new value with type TYPE, which is FIELDNO field of the
3279 object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
3280 of VAL. If the VAL's contents required to extract the bitfield
3281 from are unavailable/optimized out, the new value is
3282 correspondingly marked unavailable/optimized out. */
3283
3284 struct value *
3285 value_field_bitfield (struct type *type, int fieldno,
3286 const gdb_byte *valaddr,
3287 LONGEST embedded_offset, const struct value *val)
3288 {
3289 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3290 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3291 struct value *res_val = allocate_value (type->field (fieldno).type ());
3292
3293 unpack_value_bitfield (res_val, bitpos, bitsize,
3294 valaddr, embedded_offset, val);
3295
3296 return res_val;
3297 }
3298
3299 /* Modify the value of a bitfield. ADDR points to a block of memory in
3300 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
3301 is the desired value of the field, in host byte order. BITPOS and BITSIZE
3302 indicate which bits (in target bit order) comprise the bitfield.
3303 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
3304 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
3305
3306 void
3307 modify_field (struct type *type, gdb_byte *addr,
3308 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
3309 {
3310 enum bfd_endian byte_order = type_byte_order (type);
3311 ULONGEST oword;
3312 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
3313 LONGEST bytesize;
3314
3315 /* Normalize BITPOS. */
3316 addr += bitpos / 8;
3317 bitpos %= 8;
3318
3319 /* If a negative fieldval fits in the field in question, chop
3320 off the sign extension bits. */
3321 if ((~fieldval & ~(mask >> 1)) == 0)
3322 fieldval &= mask;
3323
3324 /* Warn if value is too big to fit in the field in question. */
3325 if (0 != (fieldval & ~mask))
3326 {
3327 /* FIXME: would like to include fieldval in the message, but
3328 we don't have a sprintf_longest. */
3329 warning (_("Value does not fit in %s bits."), plongest (bitsize));
3330
3331 /* Truncate it, otherwise adjoining fields may be corrupted. */
3332 fieldval &= mask;
3333 }
3334
3335 /* Ensure no bytes outside of the modified ones get accessed as it may cause
3336 false valgrind reports. */
3337
3338 bytesize = (bitpos + bitsize + 7) / 8;
3339 oword = extract_unsigned_integer (addr, bytesize, byte_order);
3340
3341 /* Shifting for bit field depends on endianness of the target machine. */
3342 if (byte_order == BFD_ENDIAN_BIG)
3343 bitpos = bytesize * 8 - bitpos - bitsize;
3344
3345 oword &= ~(mask << bitpos);
3346 oword |= fieldval << bitpos;
3347
3348 store_unsigned_integer (addr, bytesize, byte_order, oword);
3349 }
3350 \f
3351 /* Pack NUM into BUF using a target format of TYPE. */
3352
3353 void
3354 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
3355 {
3356 enum bfd_endian byte_order = type_byte_order (type);
3357 LONGEST len;
3358
3359 type = check_typedef (type);
3360 len = TYPE_LENGTH (type);
3361
3362 switch (type->code ())
3363 {
3364 case TYPE_CODE_RANGE:
3365 num -= type->bounds ()->bias;
3366 /* Fall through. */
3367 case TYPE_CODE_INT:
3368 case TYPE_CODE_CHAR:
3369 case TYPE_CODE_ENUM:
3370 case TYPE_CODE_FLAGS:
3371 case TYPE_CODE_BOOL:
3372 case TYPE_CODE_MEMBERPTR:
3373 if (type->bit_size_differs_p ())
3374 {
3375 unsigned bit_off = type->bit_offset ();
3376 unsigned bit_size = type->bit_size ();
3377 num &= ((ULONGEST) 1 << bit_size) - 1;
3378 num <<= bit_off;
3379 }
3380 store_signed_integer (buf, len, byte_order, num);
3381 break;
3382
3383 case TYPE_CODE_REF:
3384 case TYPE_CODE_RVALUE_REF:
3385 case TYPE_CODE_PTR:
3386 store_typed_address (buf, type, (CORE_ADDR) num);
3387 break;
3388
3389 case TYPE_CODE_FLT:
3390 case TYPE_CODE_DECFLOAT:
3391 target_float_from_longest (buf, type, num);
3392 break;
3393
3394 default:
3395 error (_("Unexpected type (%d) encountered for integer constant."),
3396 type->code ());
3397 }
3398 }
3399
3400
3401 /* Pack NUM into BUF using a target format of TYPE. */
3402
3403 static void
3404 pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
3405 {
3406 LONGEST len;
3407 enum bfd_endian byte_order;
3408
3409 type = check_typedef (type);
3410 len = TYPE_LENGTH (type);
3411 byte_order = type_byte_order (type);
3412
3413 switch (type->code ())
3414 {
3415 case TYPE_CODE_INT:
3416 case TYPE_CODE_CHAR:
3417 case TYPE_CODE_ENUM:
3418 case TYPE_CODE_FLAGS:
3419 case TYPE_CODE_BOOL:
3420 case TYPE_CODE_RANGE:
3421 case TYPE_CODE_MEMBERPTR:
3422 if (type->bit_size_differs_p ())
3423 {
3424 unsigned bit_off = type->bit_offset ();
3425 unsigned bit_size = type->bit_size ();
3426 num &= ((ULONGEST) 1 << bit_size) - 1;
3427 num <<= bit_off;
3428 }
3429 store_unsigned_integer (buf, len, byte_order, num);
3430 break;
3431
3432 case TYPE_CODE_REF:
3433 case TYPE_CODE_RVALUE_REF:
3434 case TYPE_CODE_PTR:
3435 store_typed_address (buf, type, (CORE_ADDR) num);
3436 break;
3437
3438 case TYPE_CODE_FLT:
3439 case TYPE_CODE_DECFLOAT:
3440 target_float_from_ulongest (buf, type, num);
3441 break;
3442
3443 default:
3444 error (_("Unexpected type (%d) encountered "
3445 "for unsigned integer constant."),
3446 type->code ());
3447 }
3448 }
3449
3450
3451 /* Convert C numbers into newly allocated values. */
3452
3453 struct value *
3454 value_from_longest (struct type *type, LONGEST num)
3455 {
3456 struct value *val = allocate_value (type);
3457
3458 pack_long (value_contents_raw (val), type, num);
3459 return val;
3460 }
3461
3462
3463 /* Convert C unsigned numbers into newly allocated values. */
3464
3465 struct value *
3466 value_from_ulongest (struct type *type, ULONGEST num)
3467 {
3468 struct value *val = allocate_value (type);
3469
3470 pack_unsigned_long (value_contents_raw (val), type, num);
3471
3472 return val;
3473 }
3474
3475
3476 /* Create a value representing a pointer of type TYPE to the address
3477 ADDR. */
3478
3479 struct value *
3480 value_from_pointer (struct type *type, CORE_ADDR addr)
3481 {
3482 struct value *val = allocate_value (type);
3483
3484 store_typed_address (value_contents_raw (val),
3485 check_typedef (type), addr);
3486 return val;
3487 }
3488
3489 /* Create and return a value object of TYPE containing the value D. The
3490 TYPE must be of TYPE_CODE_FLT, and must be large enough to hold D once
3491 it is converted to target format. */
3492
3493 struct value *
3494 value_from_host_double (struct type *type, double d)
3495 {
3496 struct value *value = allocate_value (type);
3497 gdb_assert (type->code () == TYPE_CODE_FLT);
3498 target_float_from_host_double (value_contents_raw (value),
3499 value_type (value), d);
3500 return value;
3501 }
3502
3503 /* Create a value of type TYPE whose contents come from VALADDR, if it
3504 is non-null, and whose memory address (in the inferior) is
3505 ADDRESS. The type of the created value may differ from the passed
3506 type TYPE. Make sure to retrieve values new type after this call.
3507 Note that TYPE is not passed through resolve_dynamic_type; this is
3508 a special API intended for use only by Ada. */
3509
3510 struct value *
3511 value_from_contents_and_address_unresolved (struct type *type,
3512 const gdb_byte *valaddr,
3513 CORE_ADDR address)
3514 {
3515 struct value *v;
3516
3517 if (valaddr == NULL)
3518 v = allocate_value_lazy (type);
3519 else
3520 v = value_from_contents (type, valaddr);
3521 VALUE_LVAL (v) = lval_memory;
3522 set_value_address (v, address);
3523 return v;
3524 }
3525
3526 /* Create a value of type TYPE whose contents come from VALADDR, if it
3527 is non-null, and whose memory address (in the inferior) is
3528 ADDRESS. The type of the created value may differ from the passed
3529 type TYPE. Make sure to retrieve values new type after this call. */
3530
3531 struct value *
3532 value_from_contents_and_address (struct type *type,
3533 const gdb_byte *valaddr,
3534 CORE_ADDR address)
3535 {
3536 gdb::array_view<const gdb_byte> view;
3537 if (valaddr != nullptr)
3538 view = gdb::make_array_view (valaddr, TYPE_LENGTH (type));
3539 struct type *resolved_type = resolve_dynamic_type (type, view, address);
3540 struct type *resolved_type_no_typedef = check_typedef (resolved_type);
3541 struct value *v;
3542
3543 if (valaddr == NULL)
3544 v = allocate_value_lazy (resolved_type);
3545 else
3546 v = value_from_contents (resolved_type, valaddr);
3547 if (TYPE_DATA_LOCATION (resolved_type_no_typedef) != NULL
3548 && TYPE_DATA_LOCATION_KIND (resolved_type_no_typedef) == PROP_CONST)
3549 address = TYPE_DATA_LOCATION_ADDR (resolved_type_no_typedef);
3550 VALUE_LVAL (v) = lval_memory;
3551 set_value_address (v, address);
3552 return v;
3553 }
3554
3555 /* Create a value of type TYPE holding the contents CONTENTS.
3556 The new value is `not_lval'. */
3557
3558 struct value *
3559 value_from_contents (struct type *type, const gdb_byte *contents)
3560 {
3561 struct value *result;
3562
3563 result = allocate_value (type);
3564 memcpy (value_contents_raw (result), contents, TYPE_LENGTH (type));
3565 return result;
3566 }
3567
3568 /* Extract a value from the history file. Input will be of the form
3569 $digits or $$digits. See block comment above 'write_dollar_variable'
3570 for details. */
3571
3572 struct value *
3573 value_from_history_ref (const char *h, const char **endp)
3574 {
3575 int index, len;
3576
3577 if (h[0] == '$')
3578 len = 1;
3579 else
3580 return NULL;
3581
3582 if (h[1] == '$')
3583 len = 2;
3584
3585 /* Find length of numeral string. */
3586 for (; isdigit (h[len]); len++)
3587 ;
3588
3589 /* Make sure numeral string is not part of an identifier. */
3590 if (h[len] == '_' || isalpha (h[len]))
3591 return NULL;
3592
3593 /* Now collect the index value. */
3594 if (h[1] == '$')
3595 {
3596 if (len == 2)
3597 {
3598 /* For some bizarre reason, "$$" is equivalent to "$$1",
3599 rather than to "$$0" as it ought to be! */
3600 index = -1;
3601 *endp += len;
3602 }
3603 else
3604 {
3605 char *local_end;
3606
3607 index = -strtol (&h[2], &local_end, 10);
3608 *endp = local_end;
3609 }
3610 }
3611 else
3612 {
3613 if (len == 1)
3614 {
3615 /* "$" is equivalent to "$0". */
3616 index = 0;
3617 *endp += len;
3618 }
3619 else
3620 {
3621 char *local_end;
3622
3623 index = strtol (&h[1], &local_end, 10);
3624 *endp = local_end;
3625 }
3626 }
3627
3628 return access_value_history (index);
3629 }
3630
3631 /* Get the component value (offset by OFFSET bytes) of a struct or
3632 union WHOLE. Component's type is TYPE. */
3633
3634 struct value *
3635 value_from_component (struct value *whole, struct type *type, LONGEST offset)
3636 {
3637 struct value *v;
3638
3639 if (VALUE_LVAL (whole) == lval_memory && value_lazy (whole))
3640 v = allocate_value_lazy (type);
3641 else
3642 {
3643 v = allocate_value (type);
3644 value_contents_copy (v, value_embedded_offset (v),
3645 whole, value_embedded_offset (whole) + offset,
3646 type_length_units (type));
3647 }
3648 v->offset = value_offset (whole) + offset + value_embedded_offset (whole);
3649 set_value_component_location (v, whole);
3650
3651 return v;
3652 }
3653
3654 struct value *
3655 coerce_ref_if_computed (const struct value *arg)
3656 {
3657 const struct lval_funcs *funcs;
3658
3659 if (!TYPE_IS_REFERENCE (check_typedef (value_type (arg))))
3660 return NULL;
3661
3662 if (value_lval_const (arg) != lval_computed)
3663 return NULL;
3664
3665 funcs = value_computed_funcs (arg);
3666 if (funcs->coerce_ref == NULL)
3667 return NULL;
3668
3669 return funcs->coerce_ref (arg);
3670 }
3671
3672 /* Look at value.h for description. */
3673
3674 struct value *
3675 readjust_indirect_value_type (struct value *value, struct type *enc_type,
3676 const struct type *original_type,
3677 struct value *original_value,
3678 CORE_ADDR original_value_address)
3679 {
3680 gdb_assert (original_type->code () == TYPE_CODE_PTR
3681 || TYPE_IS_REFERENCE (original_type));
3682
3683 struct type *original_target_type = TYPE_TARGET_TYPE (original_type);
3684 gdb::array_view<const gdb_byte> view;
3685 struct type *resolved_original_target_type
3686 = resolve_dynamic_type (original_target_type, view,
3687 original_value_address);
3688
3689 /* Re-adjust type. */
3690 deprecated_set_value_type (value, resolved_original_target_type);
3691
3692 /* Add embedding info. */
3693 set_value_enclosing_type (value, enc_type);
3694 set_value_embedded_offset (value, value_pointed_to_offset (original_value));
3695
3696 /* We may be pointing to an object of some derived type. */
3697 return value_full_object (value, NULL, 0, 0, 0);
3698 }
3699
3700 struct value *
3701 coerce_ref (struct value *arg)
3702 {
3703 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
3704 struct value *retval;
3705 struct type *enc_type;
3706
3707 retval = coerce_ref_if_computed (arg);
3708 if (retval)
3709 return retval;
3710
3711 if (!TYPE_IS_REFERENCE (value_type_arg_tmp))
3712 return arg;
3713
3714 enc_type = check_typedef (value_enclosing_type (arg));
3715 enc_type = TYPE_TARGET_TYPE (enc_type);
3716
3717 CORE_ADDR addr = unpack_pointer (value_type (arg), value_contents (arg));
3718 retval = value_at_lazy (enc_type, addr);
3719 enc_type = value_type (retval);
3720 return readjust_indirect_value_type (retval, enc_type, value_type_arg_tmp,
3721 arg, addr);
3722 }
3723
3724 struct value *
3725 coerce_array (struct value *arg)
3726 {
3727 struct type *type;
3728
3729 arg = coerce_ref (arg);
3730 type = check_typedef (value_type (arg));
3731
3732 switch (type->code ())
3733 {
3734 case TYPE_CODE_ARRAY:
3735 if (!type->is_vector () && current_language->c_style_arrays_p ())
3736 arg = value_coerce_array (arg);
3737 break;
3738 case TYPE_CODE_FUNC:
3739 arg = value_coerce_function (arg);
3740 break;
3741 }
3742 return arg;
3743 }
3744 \f
3745
3746 /* Return the return value convention that will be used for the
3747 specified type. */
3748
3749 enum return_value_convention
3750 struct_return_convention (struct gdbarch *gdbarch,
3751 struct value *function, struct type *value_type)
3752 {
3753 enum type_code code = value_type->code ();
3754
3755 if (code == TYPE_CODE_ERROR)
3756 error (_("Function return type unknown."));
3757
3758 /* Probe the architecture for the return-value convention. */
3759 return gdbarch_return_value (gdbarch, function, value_type,
3760 NULL, NULL, NULL);
3761 }
3762
3763 /* Return true if the function returning the specified type is using
3764 the convention of returning structures in memory (passing in the
3765 address as a hidden first parameter). */
3766
3767 int
3768 using_struct_return (struct gdbarch *gdbarch,
3769 struct value *function, struct type *value_type)
3770 {
3771 if (value_type->code () == TYPE_CODE_VOID)
3772 /* A void return value is never in memory. See also corresponding
3773 code in "print_return_value". */
3774 return 0;
3775
3776 return (struct_return_convention (gdbarch, function, value_type)
3777 != RETURN_VALUE_REGISTER_CONVENTION);
3778 }
3779
3780 /* Set the initialized field in a value struct. */
3781
3782 void
3783 set_value_initialized (struct value *val, int status)
3784 {
3785 val->initialized = status;
3786 }
3787
3788 /* Return the initialized field in a value struct. */
3789
3790 int
3791 value_initialized (const struct value *val)
3792 {
3793 return val->initialized;
3794 }
3795
3796 /* Helper for value_fetch_lazy when the value is a bitfield. */
3797
3798 static void
3799 value_fetch_lazy_bitfield (struct value *val)
3800 {
3801 gdb_assert (value_bitsize (val) != 0);
3802
3803 /* To read a lazy bitfield, read the entire enclosing value. This
3804 prevents reading the same block of (possibly volatile) memory once
3805 per bitfield. It would be even better to read only the containing
3806 word, but we have no way to record that just specific bits of a
3807 value have been fetched. */
3808 struct value *parent = value_parent (val);
3809
3810 if (value_lazy (parent))
3811 value_fetch_lazy (parent);
3812
3813 unpack_value_bitfield (val, value_bitpos (val), value_bitsize (val),
3814 value_contents_for_printing (parent),
3815 value_offset (val), parent);
3816 }
3817
3818 /* Helper for value_fetch_lazy when the value is in memory. */
3819
3820 static void
3821 value_fetch_lazy_memory (struct value *val)
3822 {
3823 gdb_assert (VALUE_LVAL (val) == lval_memory);
3824
3825 CORE_ADDR addr = value_address (val);
3826 struct type *type = check_typedef (value_enclosing_type (val));
3827
3828 if (TYPE_LENGTH (type))
3829 read_value_memory (val, 0, value_stack (val),
3830 addr, value_contents_all_raw (val),
3831 type_length_units (type));
3832 }
3833
3834 /* Helper for value_fetch_lazy when the value is in a register. */
3835
3836 static void
3837 value_fetch_lazy_register (struct value *val)
3838 {
3839 struct frame_info *next_frame;
3840 int regnum;
3841 struct type *type = check_typedef (value_type (val));
3842 struct value *new_val = val, *mark = value_mark ();
3843
3844 /* Offsets are not supported here; lazy register values must
3845 refer to the entire register. */
3846 gdb_assert (value_offset (val) == 0);
3847
3848 while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
3849 {
3850 struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
3851
3852 next_frame = frame_find_by_id (next_frame_id);
3853 regnum = VALUE_REGNUM (new_val);
3854
3855 gdb_assert (next_frame != NULL);
3856
3857 /* Convertible register routines are used for multi-register
3858 values and for interpretation in different types
3859 (e.g. float or int from a double register). Lazy
3860 register values should have the register's natural type,
3861 so they do not apply. */
3862 gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
3863 regnum, type));
3864
3865 /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
3866 Since a "->next" operation was performed when setting
3867 this field, we do not need to perform a "next" operation
3868 again when unwinding the register. That's why
3869 frame_unwind_register_value() is called here instead of
3870 get_frame_register_value(). */
3871 new_val = frame_unwind_register_value (next_frame, regnum);
3872
3873 /* If we get another lazy lval_register value, it means the
3874 register is found by reading it from NEXT_FRAME's next frame.
3875 frame_unwind_register_value should never return a value with
3876 the frame id pointing to NEXT_FRAME. If it does, it means we
3877 either have two consecutive frames with the same frame id
3878 in the frame chain, or some code is trying to unwind
3879 behind get_prev_frame's back (e.g., a frame unwind
3880 sniffer trying to unwind), bypassing its validations. In
3881 any case, it should always be an internal error to end up
3882 in this situation. */
3883 if (VALUE_LVAL (new_val) == lval_register
3884 && value_lazy (new_val)
3885 && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
3886 internal_error (__FILE__, __LINE__,
3887 _("infinite loop while fetching a register"));
3888 }
3889
3890 /* If it's still lazy (for instance, a saved register on the
3891 stack), fetch it. */
3892 if (value_lazy (new_val))
3893 value_fetch_lazy (new_val);
3894
3895 /* Copy the contents and the unavailability/optimized-out
3896 meta-data from NEW_VAL to VAL. */
3897 set_value_lazy (val, 0);
3898 value_contents_copy (val, value_embedded_offset (val),
3899 new_val, value_embedded_offset (new_val),
3900 type_length_units (type));
3901
3902 if (frame_debug)
3903 {
3904 struct gdbarch *gdbarch;
3905 struct frame_info *frame;
3906 /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
3907 so that the frame level will be shown correctly. */
3908 frame = frame_find_by_id (VALUE_FRAME_ID (val));
3909 regnum = VALUE_REGNUM (val);
3910 gdbarch = get_frame_arch (frame);
3911
3912 fprintf_unfiltered (gdb_stdlog,
3913 "{ value_fetch_lazy "
3914 "(frame=%d,regnum=%d(%s),...) ",
3915 frame_relative_level (frame), regnum,
3916 user_reg_map_regnum_to_name (gdbarch, regnum));
3917
3918 fprintf_unfiltered (gdb_stdlog, "->");
3919 if (value_optimized_out (new_val))
3920 {
3921 fprintf_unfiltered (gdb_stdlog, " ");
3922 val_print_optimized_out (new_val, gdb_stdlog);
3923 }
3924 else
3925 {
3926 int i;
3927 const gdb_byte *buf = value_contents (new_val);
3928
3929 if (VALUE_LVAL (new_val) == lval_register)
3930 fprintf_unfiltered (gdb_stdlog, " register=%d",
3931 VALUE_REGNUM (new_val));
3932 else if (VALUE_LVAL (new_val) == lval_memory)
3933 fprintf_unfiltered (gdb_stdlog, " address=%s",
3934 paddress (gdbarch,
3935 value_address (new_val)));
3936 else
3937 fprintf_unfiltered (gdb_stdlog, " computed");
3938
3939 fprintf_unfiltered (gdb_stdlog, " bytes=");
3940 fprintf_unfiltered (gdb_stdlog, "[");
3941 for (i = 0; i < register_size (gdbarch, regnum); i++)
3942 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
3943 fprintf_unfiltered (gdb_stdlog, "]");
3944 }
3945
3946 fprintf_unfiltered (gdb_stdlog, " }\n");
3947 }
3948
3949 /* Dispose of the intermediate values. This prevents
3950 watchpoints from trying to watch the saved frame pointer. */
3951 value_free_to_mark (mark);
3952 }
3953
3954 /* Load the actual content of a lazy value. Fetch the data from the
3955 user's process and clear the lazy flag to indicate that the data in
3956 the buffer is valid.
3957
3958 If the value is zero-length, we avoid calling read_memory, which
3959 would abort. We mark the value as fetched anyway -- all 0 bytes of
3960 it. */
3961
3962 void
3963 value_fetch_lazy (struct value *val)
3964 {
3965 gdb_assert (value_lazy (val));
3966 allocate_value_contents (val);
3967 /* A value is either lazy, or fully fetched. The
3968 availability/validity is only established as we try to fetch a
3969 value. */
3970 gdb_assert (val->optimized_out.empty ());
3971 gdb_assert (val->unavailable.empty ());
3972 if (value_bitsize (val))
3973 value_fetch_lazy_bitfield (val);
3974 else if (VALUE_LVAL (val) == lval_memory)
3975 value_fetch_lazy_memory (val);
3976 else if (VALUE_LVAL (val) == lval_register)
3977 value_fetch_lazy_register (val);
3978 else if (VALUE_LVAL (val) == lval_computed
3979 && value_computed_funcs (val)->read != NULL)
3980 value_computed_funcs (val)->read (val);
3981 else
3982 internal_error (__FILE__, __LINE__, _("Unexpected lazy value type."));
3983
3984 set_value_lazy (val, 0);
3985 }
3986
3987 /* Implementation of the convenience function $_isvoid. */
3988
3989 static struct value *
3990 isvoid_internal_fn (struct gdbarch *gdbarch,
3991 const struct language_defn *language,
3992 void *cookie, int argc, struct value **argv)
3993 {
3994 int ret;
3995
3996 if (argc != 1)
3997 error (_("You must provide one argument for $_isvoid."));
3998
3999 ret = value_type (argv[0])->code () == TYPE_CODE_VOID;
4000
4001 return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
4002 }
4003
4004 /* Implementation of the convenience function $_creal. Extracts the
4005 real part from a complex number. */
4006
4007 static struct value *
4008 creal_internal_fn (struct gdbarch *gdbarch,
4009 const struct language_defn *language,
4010 void *cookie, int argc, struct value **argv)
4011 {
4012 if (argc != 1)
4013 error (_("You must provide one argument for $_creal."));
4014
4015 value *cval = argv[0];
4016 type *ctype = check_typedef (value_type (cval));
4017 if (ctype->code () != TYPE_CODE_COMPLEX)
4018 error (_("expected a complex number"));
4019 return value_real_part (cval);
4020 }
4021
4022 /* Implementation of the convenience function $_cimag. Extracts the
4023 imaginary part from a complex number. */
4024
4025 static struct value *
4026 cimag_internal_fn (struct gdbarch *gdbarch,
4027 const struct language_defn *language,
4028 void *cookie, int argc,
4029 struct value **argv)
4030 {
4031 if (argc != 1)
4032 error (_("You must provide one argument for $_cimag."));
4033
4034 value *cval = argv[0];
4035 type *ctype = check_typedef (value_type (cval));
4036 if (ctype->code () != TYPE_CODE_COMPLEX)
4037 error (_("expected a complex number"));
4038 return value_imaginary_part (cval);
4039 }
4040
4041 #if GDB_SELF_TEST
4042 namespace selftests
4043 {
4044
4045 /* Test the ranges_contain function. */
4046
4047 static void
4048 test_ranges_contain ()
4049 {
4050 std::vector<range> ranges;
4051 range r;
4052
4053 /* [10, 14] */
4054 r.offset = 10;
4055 r.length = 5;
4056 ranges.push_back (r);
4057
4058 /* [20, 24] */
4059 r.offset = 20;
4060 r.length = 5;
4061 ranges.push_back (r);
4062
4063 /* [2, 6] */
4064 SELF_CHECK (!ranges_contain (ranges, 2, 5));
4065 /* [9, 13] */
4066 SELF_CHECK (ranges_contain (ranges, 9, 5));
4067 /* [10, 11] */
4068 SELF_CHECK (ranges_contain (ranges, 10, 2));
4069 /* [10, 14] */
4070 SELF_CHECK (ranges_contain (ranges, 10, 5));
4071 /* [13, 18] */
4072 SELF_CHECK (ranges_contain (ranges, 13, 6));
4073 /* [14, 18] */
4074 SELF_CHECK (ranges_contain (ranges, 14, 5));
4075 /* [15, 18] */
4076 SELF_CHECK (!ranges_contain (ranges, 15, 4));
4077 /* [16, 19] */
4078 SELF_CHECK (!ranges_contain (ranges, 16, 4));
4079 /* [16, 21] */
4080 SELF_CHECK (ranges_contain (ranges, 16, 6));
4081 /* [21, 21] */
4082 SELF_CHECK (ranges_contain (ranges, 21, 1));
4083 /* [21, 25] */
4084 SELF_CHECK (ranges_contain (ranges, 21, 5));
4085 /* [26, 28] */
4086 SELF_CHECK (!ranges_contain (ranges, 26, 3));
4087 }
4088
4089 /* Check that RANGES contains the same ranges as EXPECTED. */
4090
4091 static bool
4092 check_ranges_vector (gdb::array_view<const range> ranges,
4093 gdb::array_view<const range> expected)
4094 {
4095 return ranges == expected;
4096 }
4097
4098 /* Test the insert_into_bit_range_vector function. */
4099
4100 static void
4101 test_insert_into_bit_range_vector ()
4102 {
4103 std::vector<range> ranges;
4104
4105 /* [10, 14] */
4106 {
4107 insert_into_bit_range_vector (&ranges, 10, 5);
4108 static const range expected[] = {
4109 {10, 5}
4110 };
4111 SELF_CHECK (check_ranges_vector (ranges, expected));
4112 }
4113
4114 /* [10, 14] */
4115 {
4116 insert_into_bit_range_vector (&ranges, 11, 4);
4117 static const range expected = {10, 5};
4118 SELF_CHECK (check_ranges_vector (ranges, expected));
4119 }
4120
4121 /* [10, 14] [20, 24] */
4122 {
4123 insert_into_bit_range_vector (&ranges, 20, 5);
4124 static const range expected[] = {
4125 {10, 5},
4126 {20, 5},
4127 };
4128 SELF_CHECK (check_ranges_vector (ranges, expected));
4129 }
4130
4131 /* [10, 14] [17, 24] */
4132 {
4133 insert_into_bit_range_vector (&ranges, 17, 5);
4134 static const range expected[] = {
4135 {10, 5},
4136 {17, 8},
4137 };
4138 SELF_CHECK (check_ranges_vector (ranges, expected));
4139 }
4140
4141 /* [2, 8] [10, 14] [17, 24] */
4142 {
4143 insert_into_bit_range_vector (&ranges, 2, 7);
4144 static const range expected[] = {
4145 {2, 7},
4146 {10, 5},
4147 {17, 8},
4148 };
4149 SELF_CHECK (check_ranges_vector (ranges, expected));
4150 }
4151
4152 /* [2, 14] [17, 24] */
4153 {
4154 insert_into_bit_range_vector (&ranges, 9, 1);
4155 static const range expected[] = {
4156 {2, 13},
4157 {17, 8},
4158 };
4159 SELF_CHECK (check_ranges_vector (ranges, expected));
4160 }
4161
4162 /* [2, 14] [17, 24] */
4163 {
4164 insert_into_bit_range_vector (&ranges, 9, 1);
4165 static const range expected[] = {
4166 {2, 13},
4167 {17, 8},
4168 };
4169 SELF_CHECK (check_ranges_vector (ranges, expected));
4170 }
4171
4172 /* [2, 33] */
4173 {
4174 insert_into_bit_range_vector (&ranges, 4, 30);
4175 static const range expected = {2, 32};
4176 SELF_CHECK (check_ranges_vector (ranges, expected));
4177 }
4178 }
4179
4180 } /* namespace selftests */
4181 #endif /* GDB_SELF_TEST */
4182
4183 void _initialize_values ();
4184 void
4185 _initialize_values ()
4186 {
4187 add_cmd ("convenience", no_class, show_convenience, _("\
4188 Debugger convenience (\"$foo\") variables and functions.\n\
4189 Convenience variables are created when you assign them values;\n\
4190 thus, \"set $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
4191 \n\
4192 A few convenience variables are given values automatically:\n\
4193 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
4194 \"$__\" holds the contents of the last address examined with \"x\"."
4195 #ifdef HAVE_PYTHON
4196 "\n\n\
4197 Convenience functions are defined via the Python API."
4198 #endif
4199 ), &showlist);
4200 add_alias_cmd ("conv", "convenience", no_class, 1, &showlist);
4201
4202 add_cmd ("values", no_set_class, show_values, _("\
4203 Elements of value history around item number IDX (or last ten)."),
4204 &showlist);
4205
4206 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
4207 Initialize a convenience variable if necessary.\n\
4208 init-if-undefined VARIABLE = EXPRESSION\n\
4209 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
4210 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
4211 VARIABLE is already initialized."));
4212
4213 add_prefix_cmd ("function", no_class, function_command, _("\
4214 Placeholder command for showing help on convenience functions."),
4215 &functionlist, "function ", 0, &cmdlist);
4216
4217 add_internal_function ("_isvoid", _("\
4218 Check whether an expression is void.\n\
4219 Usage: $_isvoid (expression)\n\
4220 Return 1 if the expression is void, zero otherwise."),
4221 isvoid_internal_fn, NULL);
4222
4223 add_internal_function ("_creal", _("\
4224 Extract the real part of a complex number.\n\
4225 Usage: $_creal (expression)\n\
4226 Return the real part of a complex number, the type depends on the\n\
4227 type of a complex number."),
4228 creal_internal_fn, NULL);
4229
4230 add_internal_function ("_cimag", _("\
4231 Extract the imaginary part of a complex number.\n\
4232 Usage: $_cimag (expression)\n\
4233 Return the imaginary part of a complex number, the type depends on the\n\
4234 type of a complex number."),
4235 cimag_internal_fn, NULL);
4236
4237 add_setshow_zuinteger_unlimited_cmd ("max-value-size",
4238 class_support, &max_value_size, _("\
4239 Set maximum sized value gdb will load from the inferior."), _("\
4240 Show maximum sized value gdb will load from the inferior."), _("\
4241 Use this to control the maximum size, in bytes, of a value that gdb\n\
4242 will load from the inferior. Setting this value to 'unlimited'\n\
4243 disables checking.\n\
4244 Setting this does not invalidate already allocated values, it only\n\
4245 prevents future values, larger than this size, from being allocated."),
4246 set_max_value_size,
4247 show_max_value_size,
4248 &setlist, &showlist);
4249 #if GDB_SELF_TEST
4250 selftests::register_test ("ranges_contain", selftests::test_ranges_contain);
4251 selftests::register_test ("insert_into_bit_range_vector",
4252 selftests::test_insert_into_bit_range_vector);
4253 #endif
4254 }
4255
4256 /* See value.h. */
4257
4258 void
4259 finalize_values ()
4260 {
4261 all_values.clear ();
4262 }