1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986-2018 Free Software Foundation, Inc.
5 This file is part of GDB.
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.
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.
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/>. */
21 #include "arch-utils.h"
33 #include "target-float.h"
36 #include "cli/cli-decode.h"
37 #include "extension.h"
39 #include "tracepoint.h"
41 #include "user-regs.h"
43 #include "completer.h"
45 /* Definition of a user function. */
46 struct internal_function
48 /* The name of the function. It is a bit odd to have this in the
49 function itself -- the user might use a differently-named
50 convenience variable to hold the function. */
54 internal_function_fn handler;
56 /* User data for the handler. */
60 /* Defines an [OFFSET, OFFSET + LENGTH) range. */
64 /* Lowest offset in the range. */
67 /* Length of the range. */
70 /* Returns true if THIS is strictly less than OTHER, useful for
71 searching. We keep ranges sorted by offset and coalesce
72 overlapping and contiguous ranges, so this just compares the
75 bool operator< (const range &other) const
77 return offset < other.offset;
81 /* Returns true if the ranges defined by [offset1, offset1+len1) and
82 [offset2, offset2+len2) overlap. */
85 ranges_overlap (LONGEST offset1, LONGEST len1,
86 LONGEST offset2, LONGEST len2)
90 l = std::max (offset1, offset2);
91 h = std::min (offset1 + len1, offset2 + len2);
95 /* Returns true if RANGES contains any range that overlaps [OFFSET,
99 ranges_contain (const std::vector<range> &ranges, LONGEST offset,
104 what.offset = offset;
105 what.length = length;
107 /* We keep ranges sorted by offset and coalesce overlapping and
108 contiguous ranges, so to check if a range list contains a given
109 range, we can do a binary search for the position the given range
110 would be inserted if we only considered the starting OFFSET of
111 ranges. We call that position I. Since we also have LENGTH to
112 care for (this is a range afterall), we need to check if the
113 _previous_ range overlaps the I range. E.g.,
117 |---| |---| |------| ... |--|
122 In the case above, the binary search would return `I=1', meaning,
123 this OFFSET should be inserted at position 1, and the current
124 position 1 should be pushed further (and before 2). But, `0'
127 Then we need to check if the I range overlaps the I range itself.
132 |---| |---| |-------| ... |--|
139 auto i = std::lower_bound (ranges.begin (), ranges.end (), what);
141 if (i > ranges.begin ())
143 const struct range &bef = *(i - 1);
145 if (ranges_overlap (bef.offset, bef.length, offset, length))
149 if (i < ranges.end ())
151 const struct range &r = *i;
153 if (ranges_overlap (r.offset, r.length, offset, length))
160 static struct cmd_list_element *functionlist;
162 /* Note that the fields in this structure are arranged to save a bit
167 explicit value (struct type *type_)
173 enclosing_type (type_)
175 location.address = 0;
180 if (VALUE_LVAL (this) == lval_computed)
182 const struct lval_funcs *funcs = location.computed.funcs;
184 if (funcs->free_closure)
185 funcs->free_closure (this);
187 else if (VALUE_LVAL (this) == lval_xcallable)
188 delete location.xm_worker;
191 DISABLE_COPY_AND_ASSIGN (value);
193 /* Type of value; either not an lval, or one of the various
194 different possible kinds of lval. */
195 enum lval_type lval = not_lval;
197 /* Is it modifiable? Only relevant if lval != not_lval. */
198 unsigned int modifiable : 1;
200 /* If zero, contents of this value are in the contents field. If
201 nonzero, contents are in inferior. If the lval field is lval_memory,
202 the contents are in inferior memory at location.address plus offset.
203 The lval field may also be lval_register.
205 WARNING: This field is used by the code which handles watchpoints
206 (see breakpoint.c) to decide whether a particular value can be
207 watched by hardware watchpoints. If the lazy flag is set for
208 some member of a value chain, it is assumed that this member of
209 the chain doesn't need to be watched as part of watching the
210 value itself. This is how GDB avoids watching the entire struct
211 or array when the user wants to watch a single struct member or
212 array element. If you ever change the way lazy flag is set and
213 reset, be sure to consider this use as well! */
214 unsigned int lazy : 1;
216 /* If value is a variable, is it initialized or not. */
217 unsigned int initialized : 1;
219 /* If value is from the stack. If this is set, read_stack will be
220 used instead of read_memory to enable extra caching. */
221 unsigned int stack : 1;
223 /* Location of value (if lval). */
226 /* If lval == lval_memory, this is the address in the inferior */
229 /*If lval == lval_register, the value is from a register. */
232 /* Register number. */
234 /* Frame ID of "next" frame to which a register value is relative.
235 If the register value is found relative to frame F, then the
236 frame id of F->next will be stored in next_frame_id. */
237 struct frame_id next_frame_id;
240 /* Pointer to internal variable. */
241 struct internalvar *internalvar;
243 /* Pointer to xmethod worker. */
244 struct xmethod_worker *xm_worker;
246 /* If lval == lval_computed, this is a set of function pointers
247 to use to access and describe the value, and a closure pointer
251 /* Functions to call. */
252 const struct lval_funcs *funcs;
254 /* Closure for those functions to use. */
259 /* Describes offset of a value within lval of a structure in target
260 addressable memory units. Note also the member embedded_offset
264 /* Only used for bitfields; number of bits contained in them. */
267 /* Only used for bitfields; position of start of field. For
268 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
269 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
272 /* The number of references to this value. When a value is created,
273 the value chain holds a reference, so REFERENCE_COUNT is 1. If
274 release_value is called, this value is removed from the chain but
275 the caller of release_value now has a reference to this value.
276 The caller must arrange for a call to value_free later. */
277 int reference_count = 1;
279 /* Only used for bitfields; the containing value. This allows a
280 single read from the target when displaying multiple
282 value_ref_ptr parent;
284 /* Type of the value. */
287 /* If a value represents a C++ object, then the `type' field gives
288 the object's compile-time type. If the object actually belongs
289 to some class derived from `type', perhaps with other base
290 classes and additional members, then `type' is just a subobject
291 of the real thing, and the full object is probably larger than
292 `type' would suggest.
294 If `type' is a dynamic class (i.e. one with a vtable), then GDB
295 can actually determine the object's run-time type by looking at
296 the run-time type information in the vtable. When this
297 information is available, we may elect to read in the entire
298 object, for several reasons:
300 - When printing the value, the user would probably rather see the
301 full object, not just the limited portion apparent from the
304 - If `type' has virtual base classes, then even printing `type'
305 alone may require reaching outside the `type' portion of the
306 object to wherever the virtual base class has been stored.
308 When we store the entire object, `enclosing_type' is the run-time
309 type -- the complete object -- and `embedded_offset' is the
310 offset of `type' within that larger type, in target addressable memory
311 units. The value_contents() macro takes `embedded_offset' into account,
312 so most GDB code continues to see the `type' portion of the value, just
313 as the inferior would.
315 If `type' is a pointer to an object, then `enclosing_type' is a
316 pointer to the object's run-time type, and `pointed_to_offset' is
317 the offset in target addressable memory units from the full object
318 to the pointed-to object -- that is, the value `embedded_offset' would
319 have if we followed the pointer and fetched the complete object.
320 (I don't really see the point. Why not just determine the
321 run-time type when you indirect, and avoid the special case? The
322 contents don't matter until you indirect anyway.)
324 If we're not doing anything fancy, `enclosing_type' is equal to
325 `type', and `embedded_offset' is zero, so everything works
327 struct type *enclosing_type;
328 LONGEST embedded_offset = 0;
329 LONGEST pointed_to_offset = 0;
331 /* Actual contents of the value. Target byte-order. NULL or not
332 valid if lazy is nonzero. */
333 gdb::unique_xmalloc_ptr<gdb_byte> contents;
335 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
336 rather than available, since the common and default case is for a
337 value to be available. This is filled in at value read time.
338 The unavailable ranges are tracked in bits. Note that a contents
339 bit that has been optimized out doesn't really exist in the
340 program, so it can't be marked unavailable either. */
341 std::vector<range> unavailable;
343 /* Likewise, but for optimized out contents (a chunk of the value of
344 a variable that does not actually exist in the program). If LVAL
345 is lval_register, this is a register ($pc, $sp, etc., never a
346 program variable) that has not been saved in the frame. Not
347 saved registers and optimized-out program variables values are
348 treated pretty much the same, except not-saved registers have a
349 different string representation and related error strings. */
350 std::vector<range> optimized_out;
356 get_value_arch (const struct value *value)
358 return get_type_arch (value_type (value));
362 value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
364 gdb_assert (!value->lazy);
366 return !ranges_contain (value->unavailable, offset, length);
370 value_bytes_available (const struct value *value,
371 LONGEST offset, LONGEST length)
373 return value_bits_available (value,
374 offset * TARGET_CHAR_BIT,
375 length * TARGET_CHAR_BIT);
379 value_bits_any_optimized_out (const struct value *value, int bit_offset, int bit_length)
381 gdb_assert (!value->lazy);
383 return ranges_contain (value->optimized_out, bit_offset, bit_length);
387 value_entirely_available (struct value *value)
389 /* We can only tell whether the whole value is available when we try
392 value_fetch_lazy (value);
394 if (value->unavailable.empty ())
399 /* Returns true if VALUE is entirely covered by RANGES. If the value
400 is lazy, it'll be read now. Note that RANGE is a pointer to
401 pointer because reading the value might change *RANGE. */
404 value_entirely_covered_by_range_vector (struct value *value,
405 const std::vector<range> &ranges)
407 /* We can only tell whether the whole value is optimized out /
408 unavailable when we try to read it. */
410 value_fetch_lazy (value);
412 if (ranges.size () == 1)
414 const struct range &t = ranges[0];
417 && t.length == (TARGET_CHAR_BIT
418 * TYPE_LENGTH (value_enclosing_type (value))))
426 value_entirely_unavailable (struct value *value)
428 return value_entirely_covered_by_range_vector (value, value->unavailable);
432 value_entirely_optimized_out (struct value *value)
434 return value_entirely_covered_by_range_vector (value, value->optimized_out);
437 /* Insert into the vector pointed to by VECTORP the bit range starting of
438 OFFSET bits, and extending for the next LENGTH bits. */
441 insert_into_bit_range_vector (std::vector<range> *vectorp,
442 LONGEST offset, LONGEST length)
446 /* Insert the range sorted. If there's overlap or the new range
447 would be contiguous with an existing range, merge. */
449 newr.offset = offset;
450 newr.length = length;
452 /* Do a binary search for the position the given range would be
453 inserted if we only considered the starting OFFSET of ranges.
454 Call that position I. Since we also have LENGTH to care for
455 (this is a range afterall), we need to check if the _previous_
456 range overlaps the I range. E.g., calling R the new range:
458 #1 - overlaps with previous
462 |---| |---| |------| ... |--|
467 In the case #1 above, the binary search would return `I=1',
468 meaning, this OFFSET should be inserted at position 1, and the
469 current position 1 should be pushed further (and become 2). But,
470 note that `0' overlaps with R, so we want to merge them.
472 A similar consideration needs to be taken if the new range would
473 be contiguous with the previous range:
475 #2 - contiguous with previous
479 |--| |---| |------| ... |--|
484 If there's no overlap with the previous range, as in:
486 #3 - not overlapping and not contiguous
490 |--| |---| |------| ... |--|
497 #4 - R is the range with lowest offset
501 |--| |---| |------| ... |--|
506 ... we just push the new range to I.
508 All the 4 cases above need to consider that the new range may
509 also overlap several of the ranges that follow, or that R may be
510 contiguous with the following range, and merge. E.g.,
512 #5 - overlapping following ranges
515 |------------------------|
516 |--| |---| |------| ... |--|
525 |--| |---| |------| ... |--|
532 auto i = std::lower_bound (vectorp->begin (), vectorp->end (), newr);
533 if (i > vectorp->begin ())
535 struct range &bef = *(i - 1);
537 if (ranges_overlap (bef.offset, bef.length, offset, length))
540 ULONGEST l = std::min (bef.offset, offset);
541 ULONGEST h = std::max (bef.offset + bef.length, offset + length);
547 else if (offset == bef.offset + bef.length)
550 bef.length += length;
556 i = vectorp->insert (i, newr);
562 i = vectorp->insert (i, newr);
565 /* Check whether the ranges following the one we've just added or
566 touched can be folded in (#5 above). */
567 if (i != vectorp->end () && i + 1 < vectorp->end ())
572 /* Get the range we just touched. */
573 struct range &t = *i;
577 for (; i < vectorp->end (); i++)
579 struct range &r = *i;
580 if (r.offset <= t.offset + t.length)
584 l = std::min (t.offset, r.offset);
585 h = std::max (t.offset + t.length, r.offset + r.length);
594 /* If we couldn't merge this one, we won't be able to
595 merge following ones either, since the ranges are
596 always sorted by OFFSET. */
602 vectorp->erase (next, next + removed);
607 mark_value_bits_unavailable (struct value *value,
608 LONGEST offset, LONGEST length)
610 insert_into_bit_range_vector (&value->unavailable, offset, length);
614 mark_value_bytes_unavailable (struct value *value,
615 LONGEST offset, LONGEST length)
617 mark_value_bits_unavailable (value,
618 offset * TARGET_CHAR_BIT,
619 length * TARGET_CHAR_BIT);
622 /* Find the first range in RANGES that overlaps the range defined by
623 OFFSET and LENGTH, starting at element POS in the RANGES vector,
624 Returns the index into RANGES where such overlapping range was
625 found, or -1 if none was found. */
628 find_first_range_overlap (const std::vector<range> *ranges, int pos,
629 LONGEST offset, LONGEST length)
633 for (i = pos; i < ranges->size (); i++)
635 const range &r = (*ranges)[i];
636 if (ranges_overlap (r.offset, r.length, offset, length))
643 /* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
644 PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
647 It must always be the case that:
648 OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
650 It is assumed that memory can be accessed from:
651 PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
653 PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
654 / TARGET_CHAR_BIT) */
656 memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
657 const gdb_byte *ptr2, size_t offset2_bits,
660 gdb_assert (offset1_bits % TARGET_CHAR_BIT
661 == offset2_bits % TARGET_CHAR_BIT);
663 if (offset1_bits % TARGET_CHAR_BIT != 0)
666 gdb_byte mask, b1, b2;
668 /* The offset from the base pointers PTR1 and PTR2 is not a complete
669 number of bytes. A number of bits up to either the next exact
670 byte boundary, or LENGTH_BITS (which ever is sooner) will be
672 bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
673 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
674 mask = (1 << bits) - 1;
676 if (length_bits < bits)
678 mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
682 /* Now load the two bytes and mask off the bits we care about. */
683 b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
684 b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
689 /* Now update the length and offsets to take account of the bits
690 we've just compared. */
692 offset1_bits += bits;
693 offset2_bits += bits;
696 if (length_bits % TARGET_CHAR_BIT != 0)
700 gdb_byte mask, b1, b2;
702 /* The length is not an exact number of bytes. After the previous
703 IF.. block then the offsets are byte aligned, or the
704 length is zero (in which case this code is not reached). Compare
705 a number of bits at the end of the region, starting from an exact
707 bits = length_bits % TARGET_CHAR_BIT;
708 o1 = offset1_bits + length_bits - bits;
709 o2 = offset2_bits + length_bits - bits;
711 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
712 mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
714 gdb_assert (o1 % TARGET_CHAR_BIT == 0);
715 gdb_assert (o2 % TARGET_CHAR_BIT == 0);
717 b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
718 b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
728 /* We've now taken care of any stray "bits" at the start, or end of
729 the region to compare, the remainder can be covered with a simple
731 gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
732 gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
733 gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
735 return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
736 ptr2 + offset2_bits / TARGET_CHAR_BIT,
737 length_bits / TARGET_CHAR_BIT);
740 /* Length is zero, regions match. */
744 /* Helper struct for find_first_range_overlap_and_match and
745 value_contents_bits_eq. Keep track of which slot of a given ranges
746 vector have we last looked at. */
748 struct ranges_and_idx
751 const std::vector<range> *ranges;
753 /* The range we've last found in RANGES. Given ranges are sorted,
754 we can start the next lookup here. */
758 /* Helper function for value_contents_bits_eq. Compare LENGTH bits of
759 RP1's ranges starting at OFFSET1 bits with LENGTH bits of RP2's
760 ranges starting at OFFSET2 bits. Return true if the ranges match
761 and fill in *L and *H with the overlapping window relative to
762 (both) OFFSET1 or OFFSET2. */
765 find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
766 struct ranges_and_idx *rp2,
767 LONGEST offset1, LONGEST offset2,
768 LONGEST length, ULONGEST *l, ULONGEST *h)
770 rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
772 rp2->idx = find_first_range_overlap (rp2->ranges, rp2->idx,
775 if (rp1->idx == -1 && rp2->idx == -1)
781 else if (rp1->idx == -1 || rp2->idx == -1)
785 const range *r1, *r2;
789 r1 = &(*rp1->ranges)[rp1->idx];
790 r2 = &(*rp2->ranges)[rp2->idx];
792 /* Get the unavailable windows intersected by the incoming
793 ranges. The first and last ranges that overlap the argument
794 range may be wider than said incoming arguments ranges. */
795 l1 = std::max (offset1, r1->offset);
796 h1 = std::min (offset1 + length, r1->offset + r1->length);
798 l2 = std::max (offset2, r2->offset);
799 h2 = std::min (offset2 + length, offset2 + r2->length);
801 /* Make them relative to the respective start offsets, so we can
802 compare them for equality. */
809 /* Different ranges, no match. */
810 if (l1 != l2 || h1 != h2)
819 /* Helper function for value_contents_eq. The only difference is that
820 this function is bit rather than byte based.
822 Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits
823 with LENGTH bits of VAL2's contents starting at OFFSET2 bits.
824 Return true if the available bits match. */
827 value_contents_bits_eq (const struct value *val1, int offset1,
828 const struct value *val2, int offset2,
831 /* Each array element corresponds to a ranges source (unavailable,
832 optimized out). '1' is for VAL1, '2' for VAL2. */
833 struct ranges_and_idx rp1[2], rp2[2];
835 /* See function description in value.h. */
836 gdb_assert (!val1->lazy && !val2->lazy);
838 /* We shouldn't be trying to compare past the end of the values. */
839 gdb_assert (offset1 + length
840 <= TYPE_LENGTH (val1->enclosing_type) * TARGET_CHAR_BIT);
841 gdb_assert (offset2 + length
842 <= TYPE_LENGTH (val2->enclosing_type) * TARGET_CHAR_BIT);
844 memset (&rp1, 0, sizeof (rp1));
845 memset (&rp2, 0, sizeof (rp2));
846 rp1[0].ranges = &val1->unavailable;
847 rp2[0].ranges = &val2->unavailable;
848 rp1[1].ranges = &val1->optimized_out;
849 rp2[1].ranges = &val2->optimized_out;
853 ULONGEST l = 0, h = 0; /* init for gcc -Wall */
856 for (i = 0; i < 2; i++)
858 ULONGEST l_tmp, h_tmp;
860 /* The contents only match equal if the invalid/unavailable
861 contents ranges match as well. */
862 if (!find_first_range_overlap_and_match (&rp1[i], &rp2[i],
863 offset1, offset2, length,
867 /* We're interested in the lowest/first range found. */
868 if (i == 0 || l_tmp < l)
875 /* Compare the available/valid contents. */
876 if (memcmp_with_bit_offsets (val1->contents.get (), offset1,
877 val2->contents.get (), offset2, l) != 0)
889 value_contents_eq (const struct value *val1, LONGEST offset1,
890 const struct value *val2, LONGEST offset2,
893 return value_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
894 val2, offset2 * TARGET_CHAR_BIT,
895 length * TARGET_CHAR_BIT);
899 /* The value-history records all the values printed by print commands
900 during this session. */
902 static std::vector<value_ref_ptr> value_history;
905 /* List of all value objects currently allocated
906 (except for those released by calls to release_value)
907 This is so they can be freed after each command. */
909 static std::vector<value_ref_ptr> all_values;
911 /* Allocate a lazy value for type TYPE. Its actual content is
912 "lazily" allocated too: the content field of the return value is
913 NULL; it will be allocated when it is fetched from the target. */
916 allocate_value_lazy (struct type *type)
920 /* Call check_typedef on our type to make sure that, if TYPE
921 is a TYPE_CODE_TYPEDEF, its length is set to the length
922 of the target type instead of zero. However, we do not
923 replace the typedef type by the target type, because we want
924 to keep the typedef in order to be able to set the VAL's type
925 description correctly. */
926 check_typedef (type);
928 val = new struct value (type);
930 /* Values start out on the all_values chain. */
931 all_values.emplace_back (val);
936 /* The maximum size, in bytes, that GDB will try to allocate for a value.
937 The initial value of 64k was not selected for any specific reason, it is
938 just a reasonable starting point. */
940 static int max_value_size = 65536; /* 64k bytes */
942 /* It is critical that the MAX_VALUE_SIZE is at least as big as the size of
943 LONGEST, otherwise GDB will not be able to parse integer values from the
944 CLI; for example if the MAX_VALUE_SIZE could be set to 1 then GDB would
945 be unable to parse "set max-value-size 2".
947 As we want a consistent GDB experience across hosts with different sizes
948 of LONGEST, this arbitrary minimum value was selected, so long as this
949 is bigger than LONGEST on all GDB supported hosts we're fine. */
951 #define MIN_VALUE_FOR_MAX_VALUE_SIZE 16
952 gdb_static_assert (sizeof (LONGEST) <= MIN_VALUE_FOR_MAX_VALUE_SIZE);
954 /* Implement the "set max-value-size" command. */
957 set_max_value_size (const char *args, int from_tty,
958 struct cmd_list_element *c)
960 gdb_assert (max_value_size == -1 || max_value_size >= 0);
962 if (max_value_size > -1 && max_value_size < MIN_VALUE_FOR_MAX_VALUE_SIZE)
964 max_value_size = MIN_VALUE_FOR_MAX_VALUE_SIZE;
965 error (_("max-value-size set too low, increasing to %d bytes"),
970 /* Implement the "show max-value-size" command. */
973 show_max_value_size (struct ui_file *file, int from_tty,
974 struct cmd_list_element *c, const char *value)
976 if (max_value_size == -1)
977 fprintf_filtered (file, _("Maximum value size is unlimited.\n"));
979 fprintf_filtered (file, _("Maximum value size is %d bytes.\n"),
983 /* Called before we attempt to allocate or reallocate a buffer for the
984 contents of a value. TYPE is the type of the value for which we are
985 allocating the buffer. If the buffer is too large (based on the user
986 controllable setting) then throw an error. If this function returns
987 then we should attempt to allocate the buffer. */
990 check_type_length_before_alloc (const struct type *type)
992 unsigned int length = TYPE_LENGTH (type);
994 if (max_value_size > -1 && length > max_value_size)
996 if (TYPE_NAME (type) != NULL)
997 error (_("value of type `%s' requires %u bytes, which is more "
998 "than max-value-size"), TYPE_NAME (type), length);
1000 error (_("value requires %u bytes, which is more than "
1001 "max-value-size"), length);
1005 /* Allocate the contents of VAL if it has not been allocated yet. */
1008 allocate_value_contents (struct value *val)
1012 check_type_length_before_alloc (val->enclosing_type);
1014 ((gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type)));
1018 /* Allocate a value and its contents for type TYPE. */
1021 allocate_value (struct type *type)
1023 struct value *val = allocate_value_lazy (type);
1025 allocate_value_contents (val);
1030 /* Allocate a value that has the correct length
1031 for COUNT repetitions of type TYPE. */
1034 allocate_repeat_value (struct type *type, int count)
1036 int low_bound = current_language->string_lower_bound; /* ??? */
1037 /* FIXME-type-allocation: need a way to free this type when we are
1039 struct type *array_type
1040 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
1042 return allocate_value (array_type);
1046 allocate_computed_value (struct type *type,
1047 const struct lval_funcs *funcs,
1050 struct value *v = allocate_value_lazy (type);
1052 VALUE_LVAL (v) = lval_computed;
1053 v->location.computed.funcs = funcs;
1054 v->location.computed.closure = closure;
1059 /* Allocate NOT_LVAL value for type TYPE being OPTIMIZED_OUT. */
1062 allocate_optimized_out_value (struct type *type)
1064 struct value *retval = allocate_value_lazy (type);
1066 mark_value_bytes_optimized_out (retval, 0, TYPE_LENGTH (type));
1067 set_value_lazy (retval, 0);
1071 /* Accessor methods. */
1074 value_type (const struct value *value)
1079 deprecated_set_value_type (struct value *value, struct type *type)
1085 value_offset (const struct value *value)
1087 return value->offset;
1090 set_value_offset (struct value *value, LONGEST offset)
1092 value->offset = offset;
1096 value_bitpos (const struct value *value)
1098 return value->bitpos;
1101 set_value_bitpos (struct value *value, LONGEST bit)
1103 value->bitpos = bit;
1107 value_bitsize (const struct value *value)
1109 return value->bitsize;
1112 set_value_bitsize (struct value *value, LONGEST bit)
1114 value->bitsize = bit;
1118 value_parent (const struct value *value)
1120 return value->parent.get ();
1126 set_value_parent (struct value *value, struct value *parent)
1128 value->parent = value_ref_ptr (value_incref (parent));
1132 value_contents_raw (struct value *value)
1134 struct gdbarch *arch = get_value_arch (value);
1135 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1137 allocate_value_contents (value);
1138 return value->contents.get () + value->embedded_offset * unit_size;
1142 value_contents_all_raw (struct value *value)
1144 allocate_value_contents (value);
1145 return value->contents.get ();
1149 value_enclosing_type (const struct value *value)
1151 return value->enclosing_type;
1154 /* Look at value.h for description. */
1157 value_actual_type (struct value *value, int resolve_simple_types,
1158 int *real_type_found)
1160 struct value_print_options opts;
1161 struct type *result;
1163 get_user_print_options (&opts);
1165 if (real_type_found)
1166 *real_type_found = 0;
1167 result = value_type (value);
1168 if (opts.objectprint)
1170 /* If result's target type is TYPE_CODE_STRUCT, proceed to
1171 fetch its rtti type. */
1172 if ((TYPE_CODE (result) == TYPE_CODE_PTR || TYPE_IS_REFERENCE (result))
1173 && TYPE_CODE (check_typedef (TYPE_TARGET_TYPE (result)))
1175 && !value_optimized_out (value))
1177 struct type *real_type;
1179 real_type = value_rtti_indirect_type (value, NULL, NULL, NULL);
1182 if (real_type_found)
1183 *real_type_found = 1;
1187 else if (resolve_simple_types)
1189 if (real_type_found)
1190 *real_type_found = 1;
1191 result = value_enclosing_type (value);
1199 error_value_optimized_out (void)
1201 error (_("value has been optimized out"));
1205 require_not_optimized_out (const struct value *value)
1207 if (!value->optimized_out.empty ())
1209 if (value->lval == lval_register)
1210 error (_("register has not been saved in frame"));
1212 error_value_optimized_out ();
1217 require_available (const struct value *value)
1219 if (!value->unavailable.empty ())
1220 throw_error (NOT_AVAILABLE_ERROR, _("value is not available"));
1224 value_contents_for_printing (struct value *value)
1227 value_fetch_lazy (value);
1228 return value->contents.get ();
1232 value_contents_for_printing_const (const struct value *value)
1234 gdb_assert (!value->lazy);
1235 return value->contents.get ();
1239 value_contents_all (struct value *value)
1241 const gdb_byte *result = value_contents_for_printing (value);
1242 require_not_optimized_out (value);
1243 require_available (value);
1247 /* Copy ranges in SRC_RANGE that overlap [SRC_BIT_OFFSET,
1248 SRC_BIT_OFFSET+BIT_LENGTH) ranges into *DST_RANGE, adjusted. */
1251 ranges_copy_adjusted (std::vector<range> *dst_range, int dst_bit_offset,
1252 const std::vector<range> &src_range, int src_bit_offset,
1255 for (const range &r : src_range)
1259 l = std::max (r.offset, (LONGEST) src_bit_offset);
1260 h = std::min (r.offset + r.length,
1261 (LONGEST) src_bit_offset + bit_length);
1264 insert_into_bit_range_vector (dst_range,
1265 dst_bit_offset + (l - src_bit_offset),
1270 /* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
1271 SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
1274 value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
1275 const struct value *src, int src_bit_offset,
1278 ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
1279 src->unavailable, src_bit_offset,
1281 ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
1282 src->optimized_out, src_bit_offset,
1286 /* Copy LENGTH target addressable memory units of SRC value's (all) contents
1287 (value_contents_all) starting at SRC_OFFSET, into DST value's (all)
1288 contents, starting at DST_OFFSET. If unavailable contents are
1289 being copied from SRC, the corresponding DST contents are marked
1290 unavailable accordingly. Neither DST nor SRC may be lazy
1293 It is assumed the contents of DST in the [DST_OFFSET,
1294 DST_OFFSET+LENGTH) range are wholly available. */
1297 value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
1298 struct value *src, LONGEST src_offset, LONGEST length)
1300 LONGEST src_bit_offset, dst_bit_offset, bit_length;
1301 struct gdbarch *arch = get_value_arch (src);
1302 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1304 /* A lazy DST would make that this copy operation useless, since as
1305 soon as DST's contents were un-lazied (by a later value_contents
1306 call, say), the contents would be overwritten. A lazy SRC would
1307 mean we'd be copying garbage. */
1308 gdb_assert (!dst->lazy && !src->lazy);
1310 /* The overwritten DST range gets unavailability ORed in, not
1311 replaced. Make sure to remember to implement replacing if it
1312 turns out actually necessary. */
1313 gdb_assert (value_bytes_available (dst, dst_offset, length));
1314 gdb_assert (!value_bits_any_optimized_out (dst,
1315 TARGET_CHAR_BIT * dst_offset,
1316 TARGET_CHAR_BIT * length));
1318 /* Copy the data. */
1319 memcpy (value_contents_all_raw (dst) + dst_offset * unit_size,
1320 value_contents_all_raw (src) + src_offset * unit_size,
1321 length * unit_size);
1323 /* Copy the meta-data, adjusted. */
1324 src_bit_offset = src_offset * unit_size * HOST_CHAR_BIT;
1325 dst_bit_offset = dst_offset * unit_size * HOST_CHAR_BIT;
1326 bit_length = length * unit_size * HOST_CHAR_BIT;
1328 value_ranges_copy_adjusted (dst, dst_bit_offset,
1329 src, src_bit_offset,
1333 /* Copy LENGTH bytes of SRC value's (all) contents
1334 (value_contents_all) starting at SRC_OFFSET byte, into DST value's
1335 (all) contents, starting at DST_OFFSET. If unavailable contents
1336 are being copied from SRC, the corresponding DST contents are
1337 marked unavailable accordingly. DST must not be lazy. If SRC is
1338 lazy, it will be fetched now.
1340 It is assumed the contents of DST in the [DST_OFFSET,
1341 DST_OFFSET+LENGTH) range are wholly available. */
1344 value_contents_copy (struct value *dst, LONGEST dst_offset,
1345 struct value *src, LONGEST src_offset, LONGEST length)
1348 value_fetch_lazy (src);
1350 value_contents_copy_raw (dst, dst_offset, src, src_offset, length);
1354 value_lazy (const struct value *value)
1360 set_value_lazy (struct value *value, int val)
1366 value_stack (const struct value *value)
1368 return value->stack;
1372 set_value_stack (struct value *value, int val)
1378 value_contents (struct value *value)
1380 const gdb_byte *result = value_contents_writeable (value);
1381 require_not_optimized_out (value);
1382 require_available (value);
1387 value_contents_writeable (struct value *value)
1390 value_fetch_lazy (value);
1391 return value_contents_raw (value);
1395 value_optimized_out (struct value *value)
1397 /* We can only know if a value is optimized out once we have tried to
1399 if (value->optimized_out.empty () && value->lazy)
1403 value_fetch_lazy (value);
1405 CATCH (ex, RETURN_MASK_ERROR)
1407 /* Fall back to checking value->optimized_out. */
1412 return !value->optimized_out.empty ();
1415 /* Mark contents of VALUE as optimized out, starting at OFFSET bytes, and
1416 the following LENGTH bytes. */
1419 mark_value_bytes_optimized_out (struct value *value, int offset, int length)
1421 mark_value_bits_optimized_out (value,
1422 offset * TARGET_CHAR_BIT,
1423 length * TARGET_CHAR_BIT);
1429 mark_value_bits_optimized_out (struct value *value,
1430 LONGEST offset, LONGEST length)
1432 insert_into_bit_range_vector (&value->optimized_out, offset, length);
1436 value_bits_synthetic_pointer (const struct value *value,
1437 LONGEST offset, LONGEST length)
1439 if (value->lval != lval_computed
1440 || !value->location.computed.funcs->check_synthetic_pointer)
1442 return value->location.computed.funcs->check_synthetic_pointer (value,
1448 value_embedded_offset (const struct value *value)
1450 return value->embedded_offset;
1454 set_value_embedded_offset (struct value *value, LONGEST val)
1456 value->embedded_offset = val;
1460 value_pointed_to_offset (const struct value *value)
1462 return value->pointed_to_offset;
1466 set_value_pointed_to_offset (struct value *value, LONGEST val)
1468 value->pointed_to_offset = val;
1471 const struct lval_funcs *
1472 value_computed_funcs (const struct value *v)
1474 gdb_assert (value_lval_const (v) == lval_computed);
1476 return v->location.computed.funcs;
1480 value_computed_closure (const struct value *v)
1482 gdb_assert (v->lval == lval_computed);
1484 return v->location.computed.closure;
1488 deprecated_value_lval_hack (struct value *value)
1490 return &value->lval;
1494 value_lval_const (const struct value *value)
1500 value_address (const struct value *value)
1502 if (value->lval != lval_memory)
1504 if (value->parent != NULL)
1505 return value_address (value->parent.get ()) + value->offset;
1506 if (NULL != TYPE_DATA_LOCATION (value_type (value)))
1508 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (value_type (value)));
1509 return TYPE_DATA_LOCATION_ADDR (value_type (value));
1512 return value->location.address + value->offset;
1516 value_raw_address (const struct value *value)
1518 if (value->lval != lval_memory)
1520 return value->location.address;
1524 set_value_address (struct value *value, CORE_ADDR addr)
1526 gdb_assert (value->lval == lval_memory);
1527 value->location.address = addr;
1530 struct internalvar **
1531 deprecated_value_internalvar_hack (struct value *value)
1533 return &value->location.internalvar;
1537 deprecated_value_next_frame_id_hack (struct value *value)
1539 gdb_assert (value->lval == lval_register);
1540 return &value->location.reg.next_frame_id;
1544 deprecated_value_regnum_hack (struct value *value)
1546 gdb_assert (value->lval == lval_register);
1547 return &value->location.reg.regnum;
1551 deprecated_value_modifiable (const struct value *value)
1553 return value->modifiable;
1556 /* Return a mark in the value chain. All values allocated after the
1557 mark is obtained (except for those released) are subject to being freed
1558 if a subsequent value_free_to_mark is passed the mark. */
1562 if (all_values.empty ())
1564 return all_values.back ().get ();
1567 /* Take a reference to VAL. VAL will not be deallocated until all
1568 references are released. */
1571 value_incref (struct value *val)
1573 val->reference_count++;
1577 /* Release a reference to VAL, which was acquired with value_incref.
1578 This function is also called to deallocate values from the value
1582 value_decref (struct value *val)
1586 gdb_assert (val->reference_count > 0);
1587 val->reference_count--;
1588 if (val->reference_count == 0)
1593 /* Free all values allocated since MARK was obtained by value_mark
1594 (except for those released). */
1596 value_free_to_mark (const struct value *mark)
1598 auto iter = std::find (all_values.begin (), all_values.end (), mark);
1599 if (iter == all_values.end ())
1600 all_values.clear ();
1602 all_values.erase (iter + 1, all_values.end ());
1605 /* Remove VAL from the chain all_values
1606 so it will not be freed automatically. */
1609 release_value (struct value *val)
1614 return value_ref_ptr ();
1616 std::vector<value_ref_ptr>::reverse_iterator iter;
1617 for (iter = all_values.rbegin (); iter != all_values.rend (); ++iter)
1621 value_ref_ptr result = *iter;
1622 all_values.erase (iter.base () - 1);
1627 /* We must always return an owned reference. Normally this happens
1628 because we transfer the reference from the value chain, but in
1629 this case the value was not on the chain. */
1630 return value_ref_ptr (value_incref (val));
1635 std::vector<value_ref_ptr>
1636 value_release_to_mark (const struct value *mark)
1638 std::vector<value_ref_ptr> result;
1640 auto iter = std::find (all_values.begin (), all_values.end (), mark);
1641 if (iter == all_values.end ())
1642 std::swap (result, all_values);
1645 std::move (iter + 1, all_values.end (), std::back_inserter (result));
1646 all_values.erase (iter + 1, all_values.end ());
1648 std::reverse (result.begin (), result.end ());
1652 /* Return a copy of the value ARG.
1653 It contains the same contents, for same memory address,
1654 but it's a different block of storage. */
1657 value_copy (struct value *arg)
1659 struct type *encl_type = value_enclosing_type (arg);
1662 if (value_lazy (arg))
1663 val = allocate_value_lazy (encl_type);
1665 val = allocate_value (encl_type);
1666 val->type = arg->type;
1667 VALUE_LVAL (val) = VALUE_LVAL (arg);
1668 val->location = arg->location;
1669 val->offset = arg->offset;
1670 val->bitpos = arg->bitpos;
1671 val->bitsize = arg->bitsize;
1672 val->lazy = arg->lazy;
1673 val->embedded_offset = value_embedded_offset (arg);
1674 val->pointed_to_offset = arg->pointed_to_offset;
1675 val->modifiable = arg->modifiable;
1676 if (!value_lazy (val))
1678 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
1679 TYPE_LENGTH (value_enclosing_type (arg)));
1682 val->unavailable = arg->unavailable;
1683 val->optimized_out = arg->optimized_out;
1684 val->parent = arg->parent;
1685 if (VALUE_LVAL (val) == lval_computed)
1687 const struct lval_funcs *funcs = val->location.computed.funcs;
1689 if (funcs->copy_closure)
1690 val->location.computed.closure = funcs->copy_closure (val);
1695 /* Return a "const" and/or "volatile" qualified version of the value V.
1696 If CNST is true, then the returned value will be qualified with
1698 if VOLTL is true, then the returned value will be qualified with
1702 make_cv_value (int cnst, int voltl, struct value *v)
1704 struct type *val_type = value_type (v);
1705 struct type *enclosing_type = value_enclosing_type (v);
1706 struct value *cv_val = value_copy (v);
1708 deprecated_set_value_type (cv_val,
1709 make_cv_type (cnst, voltl, val_type, NULL));
1710 set_value_enclosing_type (cv_val,
1711 make_cv_type (cnst, voltl, enclosing_type, NULL));
1716 /* Return a version of ARG that is non-lvalue. */
1719 value_non_lval (struct value *arg)
1721 if (VALUE_LVAL (arg) != not_lval)
1723 struct type *enc_type = value_enclosing_type (arg);
1724 struct value *val = allocate_value (enc_type);
1726 memcpy (value_contents_all_raw (val), value_contents_all (arg),
1727 TYPE_LENGTH (enc_type));
1728 val->type = arg->type;
1729 set_value_embedded_offset (val, value_embedded_offset (arg));
1730 set_value_pointed_to_offset (val, value_pointed_to_offset (arg));
1736 /* Write contents of V at ADDR and set its lval type to be LVAL_MEMORY. */
1739 value_force_lval (struct value *v, CORE_ADDR addr)
1741 gdb_assert (VALUE_LVAL (v) == not_lval);
1743 write_memory (addr, value_contents_raw (v), TYPE_LENGTH (value_type (v)));
1744 v->lval = lval_memory;
1745 v->location.address = addr;
1749 set_value_component_location (struct value *component,
1750 const struct value *whole)
1754 gdb_assert (whole->lval != lval_xcallable);
1756 if (whole->lval == lval_internalvar)
1757 VALUE_LVAL (component) = lval_internalvar_component;
1759 VALUE_LVAL (component) = whole->lval;
1761 component->location = whole->location;
1762 if (whole->lval == lval_computed)
1764 const struct lval_funcs *funcs = whole->location.computed.funcs;
1766 if (funcs->copy_closure)
1767 component->location.computed.closure = funcs->copy_closure (whole);
1770 /* If type has a dynamic resolved location property
1771 update it's value address. */
1772 type = value_type (whole);
1773 if (NULL != TYPE_DATA_LOCATION (type)
1774 && TYPE_DATA_LOCATION_KIND (type) == PROP_CONST)
1775 set_value_address (component, TYPE_DATA_LOCATION_ADDR (type));
1778 /* Access to the value history. */
1780 /* Record a new value in the value history.
1781 Returns the absolute history index of the entry. */
1784 record_latest_value (struct value *val)
1788 /* We don't want this value to have anything to do with the inferior anymore.
1789 In particular, "set $1 = 50" should not affect the variable from which
1790 the value was taken, and fast watchpoints should be able to assume that
1791 a value on the value history never changes. */
1792 if (value_lazy (val))
1793 value_fetch_lazy (val);
1794 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1795 from. This is a bit dubious, because then *&$1 does not just return $1
1796 but the current contents of that location. c'est la vie... */
1797 val->modifiable = 0;
1799 value_history.push_back (release_value (val));
1801 return value_history.size ();
1804 /* Return a copy of the value in the history with sequence number NUM. */
1807 access_value_history (int num)
1813 absnum += value_history.size ();
1818 error (_("The history is empty."));
1820 error (_("There is only one value in the history."));
1822 error (_("History does not go back to $$%d."), -num);
1824 if (absnum > value_history.size ())
1825 error (_("History has not yet reached $%d."), absnum);
1829 return value_copy (value_history[absnum].get ());
1833 show_values (const char *num_exp, int from_tty)
1841 /* "show values +" should print from the stored position.
1842 "show values <exp>" should print around value number <exp>. */
1843 if (num_exp[0] != '+' || num_exp[1] != '\0')
1844 num = parse_and_eval_long (num_exp) - 5;
1848 /* "show values" means print the last 10 values. */
1849 num = value_history.size () - 9;
1855 for (i = num; i < num + 10 && i <= value_history.size (); i++)
1857 struct value_print_options opts;
1859 val = access_value_history (i);
1860 printf_filtered (("$%d = "), i);
1861 get_user_print_options (&opts);
1862 value_print (val, gdb_stdout, &opts);
1863 printf_filtered (("\n"));
1866 /* The next "show values +" should start after what we just printed. */
1869 /* Hitting just return after this command should do the same thing as
1870 "show values +". If num_exp is null, this is unnecessary, since
1871 "show values +" is not useful after "show values". */
1872 if (from_tty && num_exp)
1873 set_repeat_arguments ("+");
1876 enum internalvar_kind
1878 /* The internal variable is empty. */
1881 /* The value of the internal variable is provided directly as
1882 a GDB value object. */
1885 /* A fresh value is computed via a call-back routine on every
1886 access to the internal variable. */
1887 INTERNALVAR_MAKE_VALUE,
1889 /* The internal variable holds a GDB internal convenience function. */
1890 INTERNALVAR_FUNCTION,
1892 /* The variable holds an integer value. */
1893 INTERNALVAR_INTEGER,
1895 /* The variable holds a GDB-provided string. */
1899 union internalvar_data
1901 /* A value object used with INTERNALVAR_VALUE. */
1902 struct value *value;
1904 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
1907 /* The functions to call. */
1908 const struct internalvar_funcs *functions;
1910 /* The function's user-data. */
1914 /* The internal function used with INTERNALVAR_FUNCTION. */
1917 struct internal_function *function;
1918 /* True if this is the canonical name for the function. */
1922 /* An integer value used with INTERNALVAR_INTEGER. */
1925 /* If type is non-NULL, it will be used as the type to generate
1926 a value for this internal variable. If type is NULL, a default
1927 integer type for the architecture is used. */
1932 /* A string value used with INTERNALVAR_STRING. */
1936 /* Internal variables. These are variables within the debugger
1937 that hold values assigned by debugger commands.
1938 The user refers to them with a '$' prefix
1939 that does not appear in the variable names stored internally. */
1943 struct internalvar *next;
1946 /* We support various different kinds of content of an internal variable.
1947 enum internalvar_kind specifies the kind, and union internalvar_data
1948 provides the data associated with this particular kind. */
1950 enum internalvar_kind kind;
1952 union internalvar_data u;
1955 static struct internalvar *internalvars;
1957 /* If the variable does not already exist create it and give it the
1958 value given. If no value is given then the default is zero. */
1960 init_if_undefined_command (const char* args, int from_tty)
1962 struct internalvar* intvar;
1964 /* Parse the expression - this is taken from set_command(). */
1965 expression_up expr = parse_expression (args);
1967 /* Validate the expression.
1968 Was the expression an assignment?
1969 Or even an expression at all? */
1970 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
1971 error (_("Init-if-undefined requires an assignment expression."));
1973 /* Extract the variable from the parsed expression.
1974 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
1975 if (expr->elts[1].opcode != OP_INTERNALVAR)
1976 error (_("The first parameter to init-if-undefined "
1977 "should be a GDB variable."));
1978 intvar = expr->elts[2].internalvar;
1980 /* Only evaluate the expression if the lvalue is void.
1981 This may still fail if the expresssion is invalid. */
1982 if (intvar->kind == INTERNALVAR_VOID)
1983 evaluate_expression (expr.get ());
1987 /* Look up an internal variable with name NAME. NAME should not
1988 normally include a dollar sign.
1990 If the specified internal variable does not exist,
1991 the return value is NULL. */
1993 struct internalvar *
1994 lookup_only_internalvar (const char *name)
1996 struct internalvar *var;
1998 for (var = internalvars; var; var = var->next)
1999 if (strcmp (var->name, name) == 0)
2005 /* Complete NAME by comparing it to the names of internal
2009 complete_internalvar (completion_tracker &tracker, const char *name)
2011 struct internalvar *var;
2014 len = strlen (name);
2016 for (var = internalvars; var; var = var->next)
2017 if (strncmp (var->name, name, len) == 0)
2019 gdb::unique_xmalloc_ptr<char> copy (xstrdup (var->name));
2021 tracker.add_completion (std::move (copy));
2025 /* Create an internal variable with name NAME and with a void value.
2026 NAME should not normally include a dollar sign. */
2028 struct internalvar *
2029 create_internalvar (const char *name)
2031 struct internalvar *var = XNEW (struct internalvar);
2033 var->name = concat (name, (char *)NULL);
2034 var->kind = INTERNALVAR_VOID;
2035 var->next = internalvars;
2040 /* Create an internal variable with name NAME and register FUN as the
2041 function that value_of_internalvar uses to create a value whenever
2042 this variable is referenced. NAME should not normally include a
2043 dollar sign. DATA is passed uninterpreted to FUN when it is
2044 called. CLEANUP, if not NULL, is called when the internal variable
2045 is destroyed. It is passed DATA as its only argument. */
2047 struct internalvar *
2048 create_internalvar_type_lazy (const char *name,
2049 const struct internalvar_funcs *funcs,
2052 struct internalvar *var = create_internalvar (name);
2054 var->kind = INTERNALVAR_MAKE_VALUE;
2055 var->u.make_value.functions = funcs;
2056 var->u.make_value.data = data;
2060 /* See documentation in value.h. */
2063 compile_internalvar_to_ax (struct internalvar *var,
2064 struct agent_expr *expr,
2065 struct axs_value *value)
2067 if (var->kind != INTERNALVAR_MAKE_VALUE
2068 || var->u.make_value.functions->compile_to_ax == NULL)
2071 var->u.make_value.functions->compile_to_ax (var, expr, value,
2072 var->u.make_value.data);
2076 /* Look up an internal variable with name NAME. NAME should not
2077 normally include a dollar sign.
2079 If the specified internal variable does not exist,
2080 one is created, with a void value. */
2082 struct internalvar *
2083 lookup_internalvar (const char *name)
2085 struct internalvar *var;
2087 var = lookup_only_internalvar (name);
2091 return create_internalvar (name);
2094 /* Return current value of internal variable VAR. For variables that
2095 are not inherently typed, use a value type appropriate for GDBARCH. */
2098 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
2101 struct trace_state_variable *tsv;
2103 /* If there is a trace state variable of the same name, assume that
2104 is what we really want to see. */
2105 tsv = find_trace_state_variable (var->name);
2108 tsv->value_known = target_get_trace_state_variable_value (tsv->number,
2110 if (tsv->value_known)
2111 val = value_from_longest (builtin_type (gdbarch)->builtin_int64,
2114 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2120 case INTERNALVAR_VOID:
2121 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2124 case INTERNALVAR_FUNCTION:
2125 val = allocate_value (builtin_type (gdbarch)->internal_fn);
2128 case INTERNALVAR_INTEGER:
2129 if (!var->u.integer.type)
2130 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
2131 var->u.integer.val);
2133 val = value_from_longest (var->u.integer.type, var->u.integer.val);
2136 case INTERNALVAR_STRING:
2137 val = value_cstring (var->u.string, strlen (var->u.string),
2138 builtin_type (gdbarch)->builtin_char);
2141 case INTERNALVAR_VALUE:
2142 val = value_copy (var->u.value);
2143 if (value_lazy (val))
2144 value_fetch_lazy (val);
2147 case INTERNALVAR_MAKE_VALUE:
2148 val = (*var->u.make_value.functions->make_value) (gdbarch, var,
2149 var->u.make_value.data);
2153 internal_error (__FILE__, __LINE__, _("bad kind"));
2156 /* Change the VALUE_LVAL to lval_internalvar so that future operations
2157 on this value go back to affect the original internal variable.
2159 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
2160 no underlying modifyable state in the internal variable.
2162 Likewise, if the variable's value is a computed lvalue, we want
2163 references to it to produce another computed lvalue, where
2164 references and assignments actually operate through the
2165 computed value's functions.
2167 This means that internal variables with computed values
2168 behave a little differently from other internal variables:
2169 assignments to them don't just replace the previous value
2170 altogether. At the moment, this seems like the behavior we
2173 if (var->kind != INTERNALVAR_MAKE_VALUE
2174 && val->lval != lval_computed)
2176 VALUE_LVAL (val) = lval_internalvar;
2177 VALUE_INTERNALVAR (val) = var;
2184 get_internalvar_integer (struct internalvar *var, LONGEST *result)
2186 if (var->kind == INTERNALVAR_INTEGER)
2188 *result = var->u.integer.val;
2192 if (var->kind == INTERNALVAR_VALUE)
2194 struct type *type = check_typedef (value_type (var->u.value));
2196 if (TYPE_CODE (type) == TYPE_CODE_INT)
2198 *result = value_as_long (var->u.value);
2207 get_internalvar_function (struct internalvar *var,
2208 struct internal_function **result)
2212 case INTERNALVAR_FUNCTION:
2213 *result = var->u.fn.function;
2222 set_internalvar_component (struct internalvar *var,
2223 LONGEST offset, LONGEST bitpos,
2224 LONGEST bitsize, struct value *newval)
2227 struct gdbarch *arch;
2232 case INTERNALVAR_VALUE:
2233 addr = value_contents_writeable (var->u.value);
2234 arch = get_value_arch (var->u.value);
2235 unit_size = gdbarch_addressable_memory_unit_size (arch);
2238 modify_field (value_type (var->u.value), addr + offset,
2239 value_as_long (newval), bitpos, bitsize);
2241 memcpy (addr + offset * unit_size, value_contents (newval),
2242 TYPE_LENGTH (value_type (newval)));
2246 /* We can never get a component of any other kind. */
2247 internal_error (__FILE__, __LINE__, _("set_internalvar_component"));
2252 set_internalvar (struct internalvar *var, struct value *val)
2254 enum internalvar_kind new_kind;
2255 union internalvar_data new_data = { 0 };
2257 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
2258 error (_("Cannot overwrite convenience function %s"), var->name);
2260 /* Prepare new contents. */
2261 switch (TYPE_CODE (check_typedef (value_type (val))))
2263 case TYPE_CODE_VOID:
2264 new_kind = INTERNALVAR_VOID;
2267 case TYPE_CODE_INTERNAL_FUNCTION:
2268 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2269 new_kind = INTERNALVAR_FUNCTION;
2270 get_internalvar_function (VALUE_INTERNALVAR (val),
2271 &new_data.fn.function);
2272 /* Copies created here are never canonical. */
2276 new_kind = INTERNALVAR_VALUE;
2277 new_data.value = value_copy (val);
2278 new_data.value->modifiable = 1;
2280 /* Force the value to be fetched from the target now, to avoid problems
2281 later when this internalvar is referenced and the target is gone or
2283 if (value_lazy (new_data.value))
2284 value_fetch_lazy (new_data.value);
2286 /* Release the value from the value chain to prevent it from being
2287 deleted by free_all_values. From here on this function should not
2288 call error () until new_data is installed into the var->u to avoid
2290 release_value (new_data.value).release ();
2292 /* Internal variables which are created from values with a dynamic
2293 location don't need the location property of the origin anymore.
2294 The resolved dynamic location is used prior then any other address
2295 when accessing the value.
2296 If we keep it, we would still refer to the origin value.
2297 Remove the location property in case it exist. */
2298 remove_dyn_prop (DYN_PROP_DATA_LOCATION, value_type (new_data.value));
2303 /* Clean up old contents. */
2304 clear_internalvar (var);
2307 var->kind = new_kind;
2309 /* End code which must not call error(). */
2313 set_internalvar_integer (struct internalvar *var, LONGEST l)
2315 /* Clean up old contents. */
2316 clear_internalvar (var);
2318 var->kind = INTERNALVAR_INTEGER;
2319 var->u.integer.type = NULL;
2320 var->u.integer.val = l;
2324 set_internalvar_string (struct internalvar *var, const char *string)
2326 /* Clean up old contents. */
2327 clear_internalvar (var);
2329 var->kind = INTERNALVAR_STRING;
2330 var->u.string = xstrdup (string);
2334 set_internalvar_function (struct internalvar *var, struct internal_function *f)
2336 /* Clean up old contents. */
2337 clear_internalvar (var);
2339 var->kind = INTERNALVAR_FUNCTION;
2340 var->u.fn.function = f;
2341 var->u.fn.canonical = 1;
2342 /* Variables installed here are always the canonical version. */
2346 clear_internalvar (struct internalvar *var)
2348 /* Clean up old contents. */
2351 case INTERNALVAR_VALUE:
2352 value_decref (var->u.value);
2355 case INTERNALVAR_STRING:
2356 xfree (var->u.string);
2359 case INTERNALVAR_MAKE_VALUE:
2360 if (var->u.make_value.functions->destroy != NULL)
2361 var->u.make_value.functions->destroy (var->u.make_value.data);
2368 /* Reset to void kind. */
2369 var->kind = INTERNALVAR_VOID;
2373 internalvar_name (const struct internalvar *var)
2378 static struct internal_function *
2379 create_internal_function (const char *name,
2380 internal_function_fn handler, void *cookie)
2382 struct internal_function *ifn = XNEW (struct internal_function);
2384 ifn->name = xstrdup (name);
2385 ifn->handler = handler;
2386 ifn->cookie = cookie;
2391 value_internal_function_name (struct value *val)
2393 struct internal_function *ifn;
2396 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2397 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
2398 gdb_assert (result);
2404 call_internal_function (struct gdbarch *gdbarch,
2405 const struct language_defn *language,
2406 struct value *func, int argc, struct value **argv)
2408 struct internal_function *ifn;
2411 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
2412 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
2413 gdb_assert (result);
2415 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
2418 /* The 'function' command. This does nothing -- it is just a
2419 placeholder to let "help function NAME" work. This is also used as
2420 the implementation of the sub-command that is created when
2421 registering an internal function. */
2423 function_command (const char *command, int from_tty)
2428 /* Clean up if an internal function's command is destroyed. */
2430 function_destroyer (struct cmd_list_element *self, void *ignore)
2432 xfree ((char *) self->name);
2433 xfree ((char *) self->doc);
2436 /* Add a new internal function. NAME is the name of the function; DOC
2437 is a documentation string describing the function. HANDLER is
2438 called when the function is invoked. COOKIE is an arbitrary
2439 pointer which is passed to HANDLER and is intended for "user
2442 add_internal_function (const char *name, const char *doc,
2443 internal_function_fn handler, void *cookie)
2445 struct cmd_list_element *cmd;
2446 struct internal_function *ifn;
2447 struct internalvar *var = lookup_internalvar (name);
2449 ifn = create_internal_function (name, handler, cookie);
2450 set_internalvar_function (var, ifn);
2452 cmd = add_cmd (xstrdup (name), no_class, function_command, (char *) doc,
2454 cmd->destroyer = function_destroyer;
2457 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
2458 prevent cycles / duplicates. */
2461 preserve_one_value (struct value *value, struct objfile *objfile,
2462 htab_t copied_types)
2464 if (TYPE_OBJFILE (value->type) == objfile)
2465 value->type = copy_type_recursive (objfile, value->type, copied_types);
2467 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
2468 value->enclosing_type = copy_type_recursive (objfile,
2469 value->enclosing_type,
2473 /* Likewise for internal variable VAR. */
2476 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
2477 htab_t copied_types)
2481 case INTERNALVAR_INTEGER:
2482 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
2484 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
2487 case INTERNALVAR_VALUE:
2488 preserve_one_value (var->u.value, objfile, copied_types);
2493 /* Update the internal variables and value history when OBJFILE is
2494 discarded; we must copy the types out of the objfile. New global types
2495 will be created for every convenience variable which currently points to
2496 this objfile's types, and the convenience variables will be adjusted to
2497 use the new global types. */
2500 preserve_values (struct objfile *objfile)
2502 htab_t copied_types;
2503 struct internalvar *var;
2506 /* Create the hash table. We allocate on the objfile's obstack, since
2507 it is soon to be deleted. */
2508 copied_types = create_copied_types_hash (objfile);
2510 for (const value_ref_ptr &item : value_history)
2511 preserve_one_value (item.get (), objfile, copied_types);
2513 for (var = internalvars; var; var = var->next)
2514 preserve_one_internalvar (var, objfile, copied_types);
2516 preserve_ext_lang_values (objfile, copied_types);
2518 htab_delete (copied_types);
2522 show_convenience (const char *ignore, int from_tty)
2524 struct gdbarch *gdbarch = get_current_arch ();
2525 struct internalvar *var;
2527 struct value_print_options opts;
2529 get_user_print_options (&opts);
2530 for (var = internalvars; var; var = var->next)
2537 printf_filtered (("$%s = "), var->name);
2543 val = value_of_internalvar (gdbarch, var);
2544 value_print (val, gdb_stdout, &opts);
2546 CATCH (ex, RETURN_MASK_ERROR)
2548 fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
2552 printf_filtered (("\n"));
2556 /* This text does not mention convenience functions on purpose.
2557 The user can't create them except via Python, and if Python support
2558 is installed this message will never be printed ($_streq will
2560 printf_unfiltered (_("No debugger convenience variables now defined.\n"
2561 "Convenience variables have "
2562 "names starting with \"$\";\n"
2563 "use \"set\" as in \"set "
2564 "$foo = 5\" to define them.\n"));
2572 value_from_xmethod (xmethod_worker_up &&worker)
2576 v = allocate_value (builtin_type (target_gdbarch ())->xmethod);
2577 v->lval = lval_xcallable;
2578 v->location.xm_worker = worker.release ();
2584 /* Return the type of the result of TYPE_CODE_XMETHOD value METHOD. */
2587 result_type_of_xmethod (struct value *method, int argc, struct value **argv)
2589 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2590 && method->lval == lval_xcallable && argc > 0);
2592 return method->location.xm_worker->get_result_type
2593 (argv[0], argv + 1, argc - 1);
2596 /* Call the xmethod corresponding to the TYPE_CODE_XMETHOD value METHOD. */
2599 call_xmethod (struct value *method, int argc, struct value **argv)
2601 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2602 && method->lval == lval_xcallable && argc > 0);
2604 return method->location.xm_worker->invoke (argv[0], argv + 1, argc - 1);
2607 /* Extract a value as a C number (either long or double).
2608 Knows how to convert fixed values to double, or
2609 floating values to long.
2610 Does not deallocate the value. */
2613 value_as_long (struct value *val)
2615 /* This coerces arrays and functions, which is necessary (e.g.
2616 in disassemble_command). It also dereferences references, which
2617 I suspect is the most logical thing to do. */
2618 val = coerce_array (val);
2619 return unpack_long (value_type (val), value_contents (val));
2622 /* Extract a value as a C pointer. Does not deallocate the value.
2623 Note that val's type may not actually be a pointer; value_as_long
2624 handles all the cases. */
2626 value_as_address (struct value *val)
2628 struct gdbarch *gdbarch = get_type_arch (value_type (val));
2630 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2631 whether we want this to be true eventually. */
2633 /* gdbarch_addr_bits_remove is wrong if we are being called for a
2634 non-address (e.g. argument to "signal", "info break", etc.), or
2635 for pointers to char, in which the low bits *are* significant. */
2636 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
2639 /* There are several targets (IA-64, PowerPC, and others) which
2640 don't represent pointers to functions as simply the address of
2641 the function's entry point. For example, on the IA-64, a
2642 function pointer points to a two-word descriptor, generated by
2643 the linker, which contains the function's entry point, and the
2644 value the IA-64 "global pointer" register should have --- to
2645 support position-independent code. The linker generates
2646 descriptors only for those functions whose addresses are taken.
2648 On such targets, it's difficult for GDB to convert an arbitrary
2649 function address into a function pointer; it has to either find
2650 an existing descriptor for that function, or call malloc and
2651 build its own. On some targets, it is impossible for GDB to
2652 build a descriptor at all: the descriptor must contain a jump
2653 instruction; data memory cannot be executed; and code memory
2656 Upon entry to this function, if VAL is a value of type `function'
2657 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2658 value_address (val) is the address of the function. This is what
2659 you'll get if you evaluate an expression like `main'. The call
2660 to COERCE_ARRAY below actually does all the usual unary
2661 conversions, which includes converting values of type `function'
2662 to `pointer to function'. This is the challenging conversion
2663 discussed above. Then, `unpack_long' will convert that pointer
2664 back into an address.
2666 So, suppose the user types `disassemble foo' on an architecture
2667 with a strange function pointer representation, on which GDB
2668 cannot build its own descriptors, and suppose further that `foo'
2669 has no linker-built descriptor. The address->pointer conversion
2670 will signal an error and prevent the command from running, even
2671 though the next step would have been to convert the pointer
2672 directly back into the same address.
2674 The following shortcut avoids this whole mess. If VAL is a
2675 function, just return its address directly. */
2676 if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
2677 || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
2678 return value_address (val);
2680 val = coerce_array (val);
2682 /* Some architectures (e.g. Harvard), map instruction and data
2683 addresses onto a single large unified address space. For
2684 instance: An architecture may consider a large integer in the
2685 range 0x10000000 .. 0x1000ffff to already represent a data
2686 addresses (hence not need a pointer to address conversion) while
2687 a small integer would still need to be converted integer to
2688 pointer to address. Just assume such architectures handle all
2689 integer conversions in a single function. */
2693 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2694 must admonish GDB hackers to make sure its behavior matches the
2695 compiler's, whenever possible.
2697 In general, I think GDB should evaluate expressions the same way
2698 the compiler does. When the user copies an expression out of
2699 their source code and hands it to a `print' command, they should
2700 get the same value the compiler would have computed. Any
2701 deviation from this rule can cause major confusion and annoyance,
2702 and needs to be justified carefully. In other words, GDB doesn't
2703 really have the freedom to do these conversions in clever and
2706 AndrewC pointed out that users aren't complaining about how GDB
2707 casts integers to pointers; they are complaining that they can't
2708 take an address from a disassembly listing and give it to `x/i'.
2709 This is certainly important.
2711 Adding an architecture method like integer_to_address() certainly
2712 makes it possible for GDB to "get it right" in all circumstances
2713 --- the target has complete control over how things get done, so
2714 people can Do The Right Thing for their target without breaking
2715 anyone else. The standard doesn't specify how integers get
2716 converted to pointers; usually, the ABI doesn't either, but
2717 ABI-specific code is a more reasonable place to handle it. */
2719 if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR
2720 && !TYPE_IS_REFERENCE (value_type (val))
2721 && gdbarch_integer_to_address_p (gdbarch))
2722 return gdbarch_integer_to_address (gdbarch, value_type (val),
2723 value_contents (val));
2725 return unpack_long (value_type (val), value_contents (val));
2729 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2730 as a long, or as a double, assuming the raw data is described
2731 by type TYPE. Knows how to convert different sizes of values
2732 and can convert between fixed and floating point. We don't assume
2733 any alignment for the raw data. Return value is in host byte order.
2735 If you want functions and arrays to be coerced to pointers, and
2736 references to be dereferenced, call value_as_long() instead.
2738 C++: It is assumed that the front-end has taken care of
2739 all matters concerning pointers to members. A pointer
2740 to member which reaches here is considered to be equivalent
2741 to an INT (or some size). After all, it is only an offset. */
2744 unpack_long (struct type *type, const gdb_byte *valaddr)
2746 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2747 enum type_code code = TYPE_CODE (type);
2748 int len = TYPE_LENGTH (type);
2749 int nosign = TYPE_UNSIGNED (type);
2753 case TYPE_CODE_TYPEDEF:
2754 return unpack_long (check_typedef (type), valaddr);
2755 case TYPE_CODE_ENUM:
2756 case TYPE_CODE_FLAGS:
2757 case TYPE_CODE_BOOL:
2759 case TYPE_CODE_CHAR:
2760 case TYPE_CODE_RANGE:
2761 case TYPE_CODE_MEMBERPTR:
2763 return extract_unsigned_integer (valaddr, len, byte_order);
2765 return extract_signed_integer (valaddr, len, byte_order);
2768 case TYPE_CODE_DECFLOAT:
2769 return target_float_to_longest (valaddr, type);
2773 case TYPE_CODE_RVALUE_REF:
2774 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2775 whether we want this to be true eventually. */
2776 return extract_typed_address (valaddr, type);
2779 error (_("Value can't be converted to integer."));
2781 return 0; /* Placate lint. */
2784 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2785 as a CORE_ADDR, assuming the raw data is described by type TYPE.
2786 We don't assume any alignment for the raw data. Return value is in
2789 If you want functions and arrays to be coerced to pointers, and
2790 references to be dereferenced, call value_as_address() instead.
2792 C++: It is assumed that the front-end has taken care of
2793 all matters concerning pointers to members. A pointer
2794 to member which reaches here is considered to be equivalent
2795 to an INT (or some size). After all, it is only an offset. */
2798 unpack_pointer (struct type *type, const gdb_byte *valaddr)
2800 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2801 whether we want this to be true eventually. */
2802 return unpack_long (type, valaddr);
2806 is_floating_value (struct value *val)
2808 struct type *type = check_typedef (value_type (val));
2810 if (is_floating_type (type))
2812 if (!target_float_is_valid (value_contents (val), type))
2813 error (_("Invalid floating value found in program."));
2821 /* Get the value of the FIELDNO'th field (which must be static) of
2825 value_static_field (struct type *type, int fieldno)
2827 struct value *retval;
2829 switch (TYPE_FIELD_LOC_KIND (type, fieldno))
2831 case FIELD_LOC_KIND_PHYSADDR:
2832 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
2833 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
2835 case FIELD_LOC_KIND_PHYSNAME:
2837 const char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
2838 /* TYPE_FIELD_NAME (type, fieldno); */
2839 struct block_symbol sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
2841 if (sym.symbol == NULL)
2843 /* With some compilers, e.g. HP aCC, static data members are
2844 reported as non-debuggable symbols. */
2845 struct bound_minimal_symbol msym
2846 = lookup_minimal_symbol (phys_name, NULL, NULL);
2847 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
2850 retval = allocate_optimized_out_value (field_type);
2852 retval = value_at_lazy (field_type, BMSYMBOL_VALUE_ADDRESS (msym));
2855 retval = value_of_variable (sym.symbol, sym.block);
2859 gdb_assert_not_reached ("unexpected field location kind");
2865 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
2866 You have to be careful here, since the size of the data area for the value
2867 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
2868 than the old enclosing type, you have to allocate more space for the
2872 set_value_enclosing_type (struct value *val, struct type *new_encl_type)
2874 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
2876 check_type_length_before_alloc (new_encl_type);
2878 .reset ((gdb_byte *) xrealloc (val->contents.release (),
2879 TYPE_LENGTH (new_encl_type)));
2882 val->enclosing_type = new_encl_type;
2885 /* Given a value ARG1 (offset by OFFSET bytes)
2886 of a struct or union type ARG_TYPE,
2887 extract and return the value of one of its (non-static) fields.
2888 FIELDNO says which field. */
2891 value_primitive_field (struct value *arg1, LONGEST offset,
2892 int fieldno, struct type *arg_type)
2896 struct gdbarch *arch = get_value_arch (arg1);
2897 int unit_size = gdbarch_addressable_memory_unit_size (arch);
2899 arg_type = check_typedef (arg_type);
2900 type = TYPE_FIELD_TYPE (arg_type, fieldno);
2902 /* Call check_typedef on our type to make sure that, if TYPE
2903 is a TYPE_CODE_TYPEDEF, its length is set to the length
2904 of the target type instead of zero. However, we do not
2905 replace the typedef type by the target type, because we want
2906 to keep the typedef in order to be able to print the type
2907 description correctly. */
2908 check_typedef (type);
2910 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
2912 /* Handle packed fields.
2914 Create a new value for the bitfield, with bitpos and bitsize
2915 set. If possible, arrange offset and bitpos so that we can
2916 do a single aligned read of the size of the containing type.
2917 Otherwise, adjust offset to the byte containing the first
2918 bit. Assume that the address, offset, and embedded offset
2919 are sufficiently aligned. */
2921 LONGEST bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
2922 LONGEST container_bitsize = TYPE_LENGTH (type) * 8;
2924 v = allocate_value_lazy (type);
2925 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
2926 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
2927 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
2928 v->bitpos = bitpos % container_bitsize;
2930 v->bitpos = bitpos % 8;
2931 v->offset = (value_embedded_offset (arg1)
2933 + (bitpos - v->bitpos) / 8);
2934 set_value_parent (v, arg1);
2935 if (!value_lazy (arg1))
2936 value_fetch_lazy (v);
2938 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
2940 /* This field is actually a base subobject, so preserve the
2941 entire object's contents for later references to virtual
2945 /* Lazy register values with offsets are not supported. */
2946 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
2947 value_fetch_lazy (arg1);
2949 /* We special case virtual inheritance here because this
2950 requires access to the contents, which we would rather avoid
2951 for references to ordinary fields of unavailable values. */
2952 if (BASETYPE_VIA_VIRTUAL (arg_type, fieldno))
2953 boffset = baseclass_offset (arg_type, fieldno,
2954 value_contents (arg1),
2955 value_embedded_offset (arg1),
2956 value_address (arg1),
2959 boffset = TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
2961 if (value_lazy (arg1))
2962 v = allocate_value_lazy (value_enclosing_type (arg1));
2965 v = allocate_value (value_enclosing_type (arg1));
2966 value_contents_copy_raw (v, 0, arg1, 0,
2967 TYPE_LENGTH (value_enclosing_type (arg1)));
2970 v->offset = value_offset (arg1);
2971 v->embedded_offset = offset + value_embedded_offset (arg1) + boffset;
2973 else if (NULL != TYPE_DATA_LOCATION (type))
2975 /* Field is a dynamic data member. */
2977 gdb_assert (0 == offset);
2978 /* We expect an already resolved data location. */
2979 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (type));
2980 /* For dynamic data types defer memory allocation
2981 until we actual access the value. */
2982 v = allocate_value_lazy (type);
2986 /* Plain old data member */
2987 offset += (TYPE_FIELD_BITPOS (arg_type, fieldno)
2988 / (HOST_CHAR_BIT * unit_size));
2990 /* Lazy register values with offsets are not supported. */
2991 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
2992 value_fetch_lazy (arg1);
2994 if (value_lazy (arg1))
2995 v = allocate_value_lazy (type);
2998 v = allocate_value (type);
2999 value_contents_copy_raw (v, value_embedded_offset (v),
3000 arg1, value_embedded_offset (arg1) + offset,
3001 type_length_units (type));
3003 v->offset = (value_offset (arg1) + offset
3004 + value_embedded_offset (arg1));
3006 set_value_component_location (v, arg1);
3010 /* Given a value ARG1 of a struct or union type,
3011 extract and return the value of one of its (non-static) fields.
3012 FIELDNO says which field. */
3015 value_field (struct value *arg1, int fieldno)
3017 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
3020 /* Return a non-virtual function as a value.
3021 F is the list of member functions which contains the desired method.
3022 J is an index into F which provides the desired method.
3024 We only use the symbol for its address, so be happy with either a
3025 full symbol or a minimal symbol. */
3028 value_fn_field (struct value **arg1p, struct fn_field *f,
3029 int j, struct type *type,
3033 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
3034 const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
3036 struct bound_minimal_symbol msym;
3038 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0).symbol;
3041 memset (&msym, 0, sizeof (msym));
3045 gdb_assert (sym == NULL);
3046 msym = lookup_bound_minimal_symbol (physname);
3047 if (msym.minsym == NULL)
3051 v = allocate_value (ftype);
3052 VALUE_LVAL (v) = lval_memory;
3055 set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (sym)));
3059 /* The minimal symbol might point to a function descriptor;
3060 resolve it to the actual code address instead. */
3061 struct objfile *objfile = msym.objfile;
3062 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3064 set_value_address (v,
3065 gdbarch_convert_from_func_ptr_addr
3066 (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), ¤t_target));
3071 if (type != value_type (*arg1p))
3072 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
3073 value_addr (*arg1p)));
3075 /* Move the `this' pointer according to the offset.
3076 VALUE_OFFSET (*arg1p) += offset; */
3084 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at
3085 VALADDR, and store the result in *RESULT.
3086 The bitfield starts at BITPOS bits and contains BITSIZE bits; if
3087 BITSIZE is zero, then the length is taken from FIELD_TYPE.
3089 Extracting bits depends on endianness of the machine. Compute the
3090 number of least significant bits to discard. For big endian machines,
3091 we compute the total number of bits in the anonymous object, subtract
3092 off the bit count from the MSB of the object to the MSB of the
3093 bitfield, then the size of the bitfield, which leaves the LSB discard
3094 count. For little endian machines, the discard count is simply the
3095 number of bits from the LSB of the anonymous object to the LSB of the
3098 If the field is signed, we also do sign extension. */
3101 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
3102 LONGEST bitpos, LONGEST bitsize)
3104 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
3109 LONGEST read_offset;
3111 /* Read the minimum number of bytes required; there may not be
3112 enough bytes to read an entire ULONGEST. */
3113 field_type = check_typedef (field_type);
3115 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
3118 bytes_read = TYPE_LENGTH (field_type);
3119 bitsize = 8 * bytes_read;
3122 read_offset = bitpos / 8;
3124 val = extract_unsigned_integer (valaddr + read_offset,
3125 bytes_read, byte_order);
3127 /* Extract bits. See comment above. */
3129 if (gdbarch_bits_big_endian (get_type_arch (field_type)))
3130 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
3132 lsbcount = (bitpos % 8);
3135 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
3136 If the field is signed, and is negative, then sign extend. */
3138 if (bitsize < 8 * (int) sizeof (val))
3140 valmask = (((ULONGEST) 1) << bitsize) - 1;
3142 if (!TYPE_UNSIGNED (field_type))
3144 if (val & (valmask ^ (valmask >> 1)))
3154 /* Unpack a field FIELDNO of the specified TYPE, from the object at
3155 VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
3156 ORIGINAL_VALUE, which must not be NULL. See
3157 unpack_value_bits_as_long for more details. */
3160 unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
3161 LONGEST embedded_offset, int fieldno,
3162 const struct value *val, LONGEST *result)
3164 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3165 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3166 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3169 gdb_assert (val != NULL);
3171 bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3172 if (value_bits_any_optimized_out (val, bit_offset, bitsize)
3173 || !value_bits_available (val, bit_offset, bitsize))
3176 *result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3181 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous
3182 object at VALADDR. See unpack_bits_as_long for more details. */
3185 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
3187 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3188 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3189 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3191 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
3194 /* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
3195 VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
3196 the contents in DEST_VAL, zero or sign extending if the type of
3197 DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
3198 VAL. If the VAL's contents required to extract the bitfield from
3199 are unavailable/optimized out, DEST_VAL is correspondingly
3200 marked unavailable/optimized out. */
3203 unpack_value_bitfield (struct value *dest_val,
3204 LONGEST bitpos, LONGEST bitsize,
3205 const gdb_byte *valaddr, LONGEST embedded_offset,
3206 const struct value *val)
3208 enum bfd_endian byte_order;
3211 struct type *field_type = value_type (dest_val);
3213 byte_order = gdbarch_byte_order (get_type_arch (field_type));
3215 /* First, unpack and sign extend the bitfield as if it was wholly
3216 valid. Optimized out/unavailable bits are read as zero, but
3217 that's OK, as they'll end up marked below. If the VAL is
3218 wholly-invalid we may have skipped allocating its contents,
3219 though. See allocate_optimized_out_value. */
3220 if (valaddr != NULL)
3224 num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3226 store_signed_integer (value_contents_raw (dest_val),
3227 TYPE_LENGTH (field_type), byte_order, num);
3230 /* Now copy the optimized out / unavailability ranges to the right
3232 src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3233 if (byte_order == BFD_ENDIAN_BIG)
3234 dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
3237 value_ranges_copy_adjusted (dest_val, dst_bit_offset,
3238 val, src_bit_offset, bitsize);
3241 /* Return a new value with type TYPE, which is FIELDNO field of the
3242 object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
3243 of VAL. If the VAL's contents required to extract the bitfield
3244 from are unavailable/optimized out, the new value is
3245 correspondingly marked unavailable/optimized out. */
3248 value_field_bitfield (struct type *type, int fieldno,
3249 const gdb_byte *valaddr,
3250 LONGEST embedded_offset, const struct value *val)
3252 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3253 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3254 struct value *res_val = allocate_value (TYPE_FIELD_TYPE (type, fieldno));
3256 unpack_value_bitfield (res_val, bitpos, bitsize,
3257 valaddr, embedded_offset, val);
3262 /* Modify the value of a bitfield. ADDR points to a block of memory in
3263 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
3264 is the desired value of the field, in host byte order. BITPOS and BITSIZE
3265 indicate which bits (in target bit order) comprise the bitfield.
3266 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
3267 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
3270 modify_field (struct type *type, gdb_byte *addr,
3271 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
3273 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3275 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
3278 /* Normalize BITPOS. */
3282 /* If a negative fieldval fits in the field in question, chop
3283 off the sign extension bits. */
3284 if ((~fieldval & ~(mask >> 1)) == 0)
3287 /* Warn if value is too big to fit in the field in question. */
3288 if (0 != (fieldval & ~mask))
3290 /* FIXME: would like to include fieldval in the message, but
3291 we don't have a sprintf_longest. */
3292 warning (_("Value does not fit in %s bits."), plongest (bitsize));
3294 /* Truncate it, otherwise adjoining fields may be corrupted. */
3298 /* Ensure no bytes outside of the modified ones get accessed as it may cause
3299 false valgrind reports. */
3301 bytesize = (bitpos + bitsize + 7) / 8;
3302 oword = extract_unsigned_integer (addr, bytesize, byte_order);
3304 /* Shifting for bit field depends on endianness of the target machine. */
3305 if (gdbarch_bits_big_endian (get_type_arch (type)))
3306 bitpos = bytesize * 8 - bitpos - bitsize;
3308 oword &= ~(mask << bitpos);
3309 oword |= fieldval << bitpos;
3311 store_unsigned_integer (addr, bytesize, byte_order, oword);
3314 /* Pack NUM into BUF using a target format of TYPE. */
3317 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
3319 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3322 type = check_typedef (type);
3323 len = TYPE_LENGTH (type);
3325 switch (TYPE_CODE (type))
3328 case TYPE_CODE_CHAR:
3329 case TYPE_CODE_ENUM:
3330 case TYPE_CODE_FLAGS:
3331 case TYPE_CODE_BOOL:
3332 case TYPE_CODE_RANGE:
3333 case TYPE_CODE_MEMBERPTR:
3334 store_signed_integer (buf, len, byte_order, num);
3338 case TYPE_CODE_RVALUE_REF:
3340 store_typed_address (buf, type, (CORE_ADDR) num);
3344 case TYPE_CODE_DECFLOAT:
3345 target_float_from_longest (buf, type, num);
3349 error (_("Unexpected type (%d) encountered for integer constant."),
3355 /* Pack NUM into BUF using a target format of TYPE. */
3358 pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
3361 enum bfd_endian byte_order;
3363 type = check_typedef (type);
3364 len = TYPE_LENGTH (type);
3365 byte_order = gdbarch_byte_order (get_type_arch (type));
3367 switch (TYPE_CODE (type))
3370 case TYPE_CODE_CHAR:
3371 case TYPE_CODE_ENUM:
3372 case TYPE_CODE_FLAGS:
3373 case TYPE_CODE_BOOL:
3374 case TYPE_CODE_RANGE:
3375 case TYPE_CODE_MEMBERPTR:
3376 store_unsigned_integer (buf, len, byte_order, num);
3380 case TYPE_CODE_RVALUE_REF:
3382 store_typed_address (buf, type, (CORE_ADDR) num);
3386 case TYPE_CODE_DECFLOAT:
3387 target_float_from_ulongest (buf, type, num);
3391 error (_("Unexpected type (%d) encountered "
3392 "for unsigned integer constant."),
3398 /* Convert C numbers into newly allocated values. */
3401 value_from_longest (struct type *type, LONGEST num)
3403 struct value *val = allocate_value (type);
3405 pack_long (value_contents_raw (val), type, num);
3410 /* Convert C unsigned numbers into newly allocated values. */
3413 value_from_ulongest (struct type *type, ULONGEST num)
3415 struct value *val = allocate_value (type);
3417 pack_unsigned_long (value_contents_raw (val), type, num);
3423 /* Create a value representing a pointer of type TYPE to the address
3427 value_from_pointer (struct type *type, CORE_ADDR addr)
3429 struct value *val = allocate_value (type);
3431 store_typed_address (value_contents_raw (val),
3432 check_typedef (type), addr);
3437 /* Create a value of type TYPE whose contents come from VALADDR, if it
3438 is non-null, and whose memory address (in the inferior) is
3439 ADDRESS. The type of the created value may differ from the passed
3440 type TYPE. Make sure to retrieve values new type after this call.
3441 Note that TYPE is not passed through resolve_dynamic_type; this is
3442 a special API intended for use only by Ada. */
3445 value_from_contents_and_address_unresolved (struct type *type,
3446 const gdb_byte *valaddr,
3451 if (valaddr == NULL)
3452 v = allocate_value_lazy (type);
3454 v = value_from_contents (type, valaddr);
3455 VALUE_LVAL (v) = lval_memory;
3456 set_value_address (v, address);
3460 /* Create a value of type TYPE whose contents come from VALADDR, if it
3461 is non-null, and whose memory address (in the inferior) is
3462 ADDRESS. The type of the created value may differ from the passed
3463 type TYPE. Make sure to retrieve values new type after this call. */
3466 value_from_contents_and_address (struct type *type,
3467 const gdb_byte *valaddr,
3470 struct type *resolved_type = resolve_dynamic_type (type, valaddr, address);
3471 struct type *resolved_type_no_typedef = check_typedef (resolved_type);
3474 if (valaddr == NULL)
3475 v = allocate_value_lazy (resolved_type);
3477 v = value_from_contents (resolved_type, valaddr);
3478 if (TYPE_DATA_LOCATION (resolved_type_no_typedef) != NULL
3479 && TYPE_DATA_LOCATION_KIND (resolved_type_no_typedef) == PROP_CONST)
3480 address = TYPE_DATA_LOCATION_ADDR (resolved_type_no_typedef);
3481 VALUE_LVAL (v) = lval_memory;
3482 set_value_address (v, address);
3486 /* Create a value of type TYPE holding the contents CONTENTS.
3487 The new value is `not_lval'. */
3490 value_from_contents (struct type *type, const gdb_byte *contents)
3492 struct value *result;
3494 result = allocate_value (type);
3495 memcpy (value_contents_raw (result), contents, TYPE_LENGTH (type));
3499 /* Extract a value from the history file. Input will be of the form
3500 $digits or $$digits. See block comment above 'write_dollar_variable'
3504 value_from_history_ref (const char *h, const char **endp)
3516 /* Find length of numeral string. */
3517 for (; isdigit (h[len]); len++)
3520 /* Make sure numeral string is not part of an identifier. */
3521 if (h[len] == '_' || isalpha (h[len]))
3524 /* Now collect the index value. */
3529 /* For some bizarre reason, "$$" is equivalent to "$$1",
3530 rather than to "$$0" as it ought to be! */
3538 index = -strtol (&h[2], &local_end, 10);
3546 /* "$" is equivalent to "$0". */
3554 index = strtol (&h[1], &local_end, 10);
3559 return access_value_history (index);
3562 /* Get the component value (offset by OFFSET bytes) of a struct or
3563 union WHOLE. Component's type is TYPE. */
3566 value_from_component (struct value *whole, struct type *type, LONGEST offset)
3570 if (VALUE_LVAL (whole) == lval_memory && value_lazy (whole))
3571 v = allocate_value_lazy (type);
3574 v = allocate_value (type);
3575 value_contents_copy (v, value_embedded_offset (v),
3576 whole, value_embedded_offset (whole) + offset,
3577 type_length_units (type));
3579 v->offset = value_offset (whole) + offset + value_embedded_offset (whole);
3580 set_value_component_location (v, whole);
3586 coerce_ref_if_computed (const struct value *arg)
3588 const struct lval_funcs *funcs;
3590 if (!TYPE_IS_REFERENCE (check_typedef (value_type (arg))))
3593 if (value_lval_const (arg) != lval_computed)
3596 funcs = value_computed_funcs (arg);
3597 if (funcs->coerce_ref == NULL)
3600 return funcs->coerce_ref (arg);
3603 /* Look at value.h for description. */
3606 readjust_indirect_value_type (struct value *value, struct type *enc_type,
3607 const struct type *original_type,
3608 const struct value *original_value)
3610 /* Re-adjust type. */
3611 deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
3613 /* Add embedding info. */
3614 set_value_enclosing_type (value, enc_type);
3615 set_value_embedded_offset (value, value_pointed_to_offset (original_value));
3617 /* We may be pointing to an object of some derived type. */
3618 return value_full_object (value, NULL, 0, 0, 0);
3622 coerce_ref (struct value *arg)
3624 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
3625 struct value *retval;
3626 struct type *enc_type;
3628 retval = coerce_ref_if_computed (arg);
3632 if (!TYPE_IS_REFERENCE (value_type_arg_tmp))
3635 enc_type = check_typedef (value_enclosing_type (arg));
3636 enc_type = TYPE_TARGET_TYPE (enc_type);
3638 retval = value_at_lazy (enc_type,
3639 unpack_pointer (value_type (arg),
3640 value_contents (arg)));
3641 enc_type = value_type (retval);
3642 return readjust_indirect_value_type (retval, enc_type,
3643 value_type_arg_tmp, arg);
3647 coerce_array (struct value *arg)
3651 arg = coerce_ref (arg);
3652 type = check_typedef (value_type (arg));
3654 switch (TYPE_CODE (type))
3656 case TYPE_CODE_ARRAY:
3657 if (!TYPE_VECTOR (type) && current_language->c_style_arrays)
3658 arg = value_coerce_array (arg);
3660 case TYPE_CODE_FUNC:
3661 arg = value_coerce_function (arg);
3668 /* Return the return value convention that will be used for the
3671 enum return_value_convention
3672 struct_return_convention (struct gdbarch *gdbarch,
3673 struct value *function, struct type *value_type)
3675 enum type_code code = TYPE_CODE (value_type);
3677 if (code == TYPE_CODE_ERROR)
3678 error (_("Function return type unknown."));
3680 /* Probe the architecture for the return-value convention. */
3681 return gdbarch_return_value (gdbarch, function, value_type,
3685 /* Return true if the function returning the specified type is using
3686 the convention of returning structures in memory (passing in the
3687 address as a hidden first parameter). */
3690 using_struct_return (struct gdbarch *gdbarch,
3691 struct value *function, struct type *value_type)
3693 if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
3694 /* A void return value is never in memory. See also corresponding
3695 code in "print_return_value". */
3698 return (struct_return_convention (gdbarch, function, value_type)
3699 != RETURN_VALUE_REGISTER_CONVENTION);
3702 /* Set the initialized field in a value struct. */
3705 set_value_initialized (struct value *val, int status)
3707 val->initialized = status;
3710 /* Return the initialized field in a value struct. */
3713 value_initialized (const struct value *val)
3715 return val->initialized;
3718 /* Load the actual content of a lazy value. Fetch the data from the
3719 user's process and clear the lazy flag to indicate that the data in
3720 the buffer is valid.
3722 If the value is zero-length, we avoid calling read_memory, which
3723 would abort. We mark the value as fetched anyway -- all 0 bytes of
3727 value_fetch_lazy (struct value *val)
3729 gdb_assert (value_lazy (val));
3730 allocate_value_contents (val);
3731 /* A value is either lazy, or fully fetched. The
3732 availability/validity is only established as we try to fetch a
3734 gdb_assert (val->optimized_out.empty ());
3735 gdb_assert (val->unavailable.empty ());
3736 if (value_bitsize (val))
3738 /* To read a lazy bitfield, read the entire enclosing value. This
3739 prevents reading the same block of (possibly volatile) memory once
3740 per bitfield. It would be even better to read only the containing
3741 word, but we have no way to record that just specific bits of a
3742 value have been fetched. */
3743 struct type *type = check_typedef (value_type (val));
3744 struct value *parent = value_parent (val);
3746 if (value_lazy (parent))
3747 value_fetch_lazy (parent);
3749 unpack_value_bitfield (val,
3750 value_bitpos (val), value_bitsize (val),
3751 value_contents_for_printing (parent),
3752 value_offset (val), parent);
3754 else if (VALUE_LVAL (val) == lval_memory)
3756 CORE_ADDR addr = value_address (val);
3757 struct type *type = check_typedef (value_enclosing_type (val));
3759 if (TYPE_LENGTH (type))
3760 read_value_memory (val, 0, value_stack (val),
3761 addr, value_contents_all_raw (val),
3762 type_length_units (type));
3764 else if (VALUE_LVAL (val) == lval_register)
3766 struct frame_info *next_frame;
3768 struct type *type = check_typedef (value_type (val));
3769 struct value *new_val = val, *mark = value_mark ();
3771 /* Offsets are not supported here; lazy register values must
3772 refer to the entire register. */
3773 gdb_assert (value_offset (val) == 0);
3775 while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
3777 struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
3779 next_frame = frame_find_by_id (next_frame_id);
3780 regnum = VALUE_REGNUM (new_val);
3782 gdb_assert (next_frame != NULL);
3784 /* Convertible register routines are used for multi-register
3785 values and for interpretation in different types
3786 (e.g. float or int from a double register). Lazy
3787 register values should have the register's natural type,
3788 so they do not apply. */
3789 gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
3792 /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
3793 Since a "->next" operation was performed when setting
3794 this field, we do not need to perform a "next" operation
3795 again when unwinding the register. That's why
3796 frame_unwind_register_value() is called here instead of
3797 get_frame_register_value(). */
3798 new_val = frame_unwind_register_value (next_frame, regnum);
3800 /* If we get another lazy lval_register value, it means the
3801 register is found by reading it from NEXT_FRAME's next frame.
3802 frame_unwind_register_value should never return a value with
3803 the frame id pointing to NEXT_FRAME. If it does, it means we
3804 either have two consecutive frames with the same frame id
3805 in the frame chain, or some code is trying to unwind
3806 behind get_prev_frame's back (e.g., a frame unwind
3807 sniffer trying to unwind), bypassing its validations. In
3808 any case, it should always be an internal error to end up
3809 in this situation. */
3810 if (VALUE_LVAL (new_val) == lval_register
3811 && value_lazy (new_val)
3812 && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
3813 internal_error (__FILE__, __LINE__,
3814 _("infinite loop while fetching a register"));
3817 /* If it's still lazy (for instance, a saved register on the
3818 stack), fetch it. */
3819 if (value_lazy (new_val))
3820 value_fetch_lazy (new_val);
3822 /* Copy the contents and the unavailability/optimized-out
3823 meta-data from NEW_VAL to VAL. */
3824 set_value_lazy (val, 0);
3825 value_contents_copy (val, value_embedded_offset (val),
3826 new_val, value_embedded_offset (new_val),
3827 type_length_units (type));
3831 struct gdbarch *gdbarch;
3832 struct frame_info *frame;
3833 /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
3834 so that the frame level will be shown correctly. */
3835 frame = frame_find_by_id (VALUE_FRAME_ID (val));
3836 regnum = VALUE_REGNUM (val);
3837 gdbarch = get_frame_arch (frame);
3839 fprintf_unfiltered (gdb_stdlog,
3840 "{ value_fetch_lazy "
3841 "(frame=%d,regnum=%d(%s),...) ",
3842 frame_relative_level (frame), regnum,
3843 user_reg_map_regnum_to_name (gdbarch, regnum));
3845 fprintf_unfiltered (gdb_stdlog, "->");
3846 if (value_optimized_out (new_val))
3848 fprintf_unfiltered (gdb_stdlog, " ");
3849 val_print_optimized_out (new_val, gdb_stdlog);
3854 const gdb_byte *buf = value_contents (new_val);
3856 if (VALUE_LVAL (new_val) == lval_register)
3857 fprintf_unfiltered (gdb_stdlog, " register=%d",
3858 VALUE_REGNUM (new_val));
3859 else if (VALUE_LVAL (new_val) == lval_memory)
3860 fprintf_unfiltered (gdb_stdlog, " address=%s",
3862 value_address (new_val)));
3864 fprintf_unfiltered (gdb_stdlog, " computed");
3866 fprintf_unfiltered (gdb_stdlog, " bytes=");
3867 fprintf_unfiltered (gdb_stdlog, "[");
3868 for (i = 0; i < register_size (gdbarch, regnum); i++)
3869 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
3870 fprintf_unfiltered (gdb_stdlog, "]");
3873 fprintf_unfiltered (gdb_stdlog, " }\n");
3876 /* Dispose of the intermediate values. This prevents
3877 watchpoints from trying to watch the saved frame pointer. */
3878 value_free_to_mark (mark);
3880 else if (VALUE_LVAL (val) == lval_computed
3881 && value_computed_funcs (val)->read != NULL)
3882 value_computed_funcs (val)->read (val);
3884 internal_error (__FILE__, __LINE__, _("Unexpected lazy value type."));
3886 set_value_lazy (val, 0);
3889 /* Implementation of the convenience function $_isvoid. */
3891 static struct value *
3892 isvoid_internal_fn (struct gdbarch *gdbarch,
3893 const struct language_defn *language,
3894 void *cookie, int argc, struct value **argv)
3899 error (_("You must provide one argument for $_isvoid."));
3901 ret = TYPE_CODE (value_type (argv[0])) == TYPE_CODE_VOID;
3903 return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
3907 _initialize_values (void)
3909 add_cmd ("convenience", no_class, show_convenience, _("\
3910 Debugger convenience (\"$foo\") variables and functions.\n\
3911 Convenience variables are created when you assign them values;\n\
3912 thus, \"set $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
3914 A few convenience variables are given values automatically:\n\
3915 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
3916 \"$__\" holds the contents of the last address examined with \"x\"."
3919 Convenience functions are defined via the Python API."
3922 add_alias_cmd ("conv", "convenience", no_class, 1, &showlist);
3924 add_cmd ("values", no_set_class, show_values, _("\
3925 Elements of value history around item number IDX (or last ten)."),
3928 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
3929 Initialize a convenience variable if necessary.\n\
3930 init-if-undefined VARIABLE = EXPRESSION\n\
3931 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
3932 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
3933 VARIABLE is already initialized."));
3935 add_prefix_cmd ("function", no_class, function_command, _("\
3936 Placeholder command for showing help on convenience functions."),
3937 &functionlist, "function ", 0, &cmdlist);
3939 add_internal_function ("_isvoid", _("\
3940 Check whether an expression is void.\n\
3941 Usage: $_isvoid (expression)\n\
3942 Return 1 if the expression is void, zero otherwise."),
3943 isvoid_internal_fn, NULL);
3945 add_setshow_zuinteger_unlimited_cmd ("max-value-size",
3946 class_support, &max_value_size, _("\
3947 Set maximum sized value gdb will load from the inferior."), _("\
3948 Show maximum sized value gdb will load from the inferior."), _("\
3949 Use this to control the maximum size, in bytes, of a value that gdb\n\
3950 will load from the inferior. Setting this value to 'unlimited'\n\
3951 disables checking.\n\
3952 Setting this does not invalidate already allocated values, it only\n\
3953 prevents future values, larger than this size, from being allocated."),
3955 show_max_value_size,
3956 &setlist, &showlist);