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. */
71 typedef struct range range_s;
75 /* Returns true if the ranges defined by [offset1, offset1+len1) and
76 [offset2, offset2+len2) overlap. */
79 ranges_overlap (LONGEST offset1, LONGEST len1,
80 LONGEST offset2, LONGEST len2)
84 l = std::max (offset1, offset2);
85 h = std::min (offset1 + len1, offset2 + len2);
89 /* Returns true if the first argument is strictly less than the
90 second, useful for VEC_lower_bound. We keep ranges sorted by
91 offset and coalesce overlapping and contiguous ranges, so this just
92 compares the starting offset. */
95 range_lessthan (const range_s *r1, const range_s *r2)
97 return r1->offset < r2->offset;
100 /* Returns true if RANGES contains any range that overlaps [OFFSET,
104 ranges_contain (VEC(range_s) *ranges, LONGEST offset, LONGEST length)
109 what.offset = offset;
110 what.length = length;
112 /* We keep ranges sorted by offset and coalesce overlapping and
113 contiguous ranges, so to check if a range list contains a given
114 range, we can do a binary search for the position the given range
115 would be inserted if we only considered the starting OFFSET of
116 ranges. We call that position I. Since we also have LENGTH to
117 care for (this is a range afterall), we need to check if the
118 _previous_ range overlaps the I range. E.g.,
122 |---| |---| |------| ... |--|
127 In the case above, the binary search would return `I=1', meaning,
128 this OFFSET should be inserted at position 1, and the current
129 position 1 should be pushed further (and before 2). But, `0'
132 Then we need to check if the I range overlaps the I range itself.
137 |---| |---| |-------| ... |--|
143 i = VEC_lower_bound (range_s, ranges, &what, range_lessthan);
147 struct range *bef = VEC_index (range_s, ranges, i - 1);
149 if (ranges_overlap (bef->offset, bef->length, offset, length))
153 if (i < VEC_length (range_s, ranges))
155 struct range *r = VEC_index (range_s, ranges, i);
157 if (ranges_overlap (r->offset, r->length, offset, length))
164 static struct cmd_list_element *functionlist;
166 /* Note that the fields in this structure are arranged to save a bit
171 /* Type of value; either not an lval, or one of the various
172 different possible kinds of lval. */
175 /* Is it modifiable? Only relevant if lval != not_lval. */
176 unsigned int modifiable : 1;
178 /* If zero, contents of this value are in the contents field. If
179 nonzero, contents are in inferior. If the lval field is lval_memory,
180 the contents are in inferior memory at location.address plus offset.
181 The lval field may also be lval_register.
183 WARNING: This field is used by the code which handles watchpoints
184 (see breakpoint.c) to decide whether a particular value can be
185 watched by hardware watchpoints. If the lazy flag is set for
186 some member of a value chain, it is assumed that this member of
187 the chain doesn't need to be watched as part of watching the
188 value itself. This is how GDB avoids watching the entire struct
189 or array when the user wants to watch a single struct member or
190 array element. If you ever change the way lazy flag is set and
191 reset, be sure to consider this use as well! */
192 unsigned int lazy : 1;
194 /* If value is a variable, is it initialized or not. */
195 unsigned int initialized : 1;
197 /* If value is from the stack. If this is set, read_stack will be
198 used instead of read_memory to enable extra caching. */
199 unsigned int stack : 1;
201 /* If the value has been released. */
202 unsigned int released : 1;
204 /* Location of value (if lval). */
207 /* If lval == lval_memory, this is the address in the inferior */
210 /*If lval == lval_register, the value is from a register. */
213 /* Register number. */
215 /* Frame ID of "next" frame to which a register value is relative.
216 If the register value is found relative to frame F, then the
217 frame id of F->next will be stored in next_frame_id. */
218 struct frame_id next_frame_id;
221 /* Pointer to internal variable. */
222 struct internalvar *internalvar;
224 /* Pointer to xmethod worker. */
225 struct xmethod_worker *xm_worker;
227 /* If lval == lval_computed, this is a set of function pointers
228 to use to access and describe the value, and a closure pointer
232 /* Functions to call. */
233 const struct lval_funcs *funcs;
235 /* Closure for those functions to use. */
240 /* Describes offset of a value within lval of a structure in target
241 addressable memory units. Note also the member embedded_offset
245 /* Only used for bitfields; number of bits contained in them. */
248 /* Only used for bitfields; position of start of field. For
249 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
250 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
253 /* The number of references to this value. When a value is created,
254 the value chain holds a reference, so REFERENCE_COUNT is 1. If
255 release_value is called, this value is removed from the chain but
256 the caller of release_value now has a reference to this value.
257 The caller must arrange for a call to value_free later. */
260 /* Only used for bitfields; the containing value. This allows a
261 single read from the target when displaying multiple
263 struct value *parent;
265 /* Type of the value. */
268 /* If a value represents a C++ object, then the `type' field gives
269 the object's compile-time type. If the object actually belongs
270 to some class derived from `type', perhaps with other base
271 classes and additional members, then `type' is just a subobject
272 of the real thing, and the full object is probably larger than
273 `type' would suggest.
275 If `type' is a dynamic class (i.e. one with a vtable), then GDB
276 can actually determine the object's run-time type by looking at
277 the run-time type information in the vtable. When this
278 information is available, we may elect to read in the entire
279 object, for several reasons:
281 - When printing the value, the user would probably rather see the
282 full object, not just the limited portion apparent from the
285 - If `type' has virtual base classes, then even printing `type'
286 alone may require reaching outside the `type' portion of the
287 object to wherever the virtual base class has been stored.
289 When we store the entire object, `enclosing_type' is the run-time
290 type -- the complete object -- and `embedded_offset' is the
291 offset of `type' within that larger type, in target addressable memory
292 units. The value_contents() macro takes `embedded_offset' into account,
293 so most GDB code continues to see the `type' portion of the value, just
294 as the inferior would.
296 If `type' is a pointer to an object, then `enclosing_type' is a
297 pointer to the object's run-time type, and `pointed_to_offset' is
298 the offset in target addressable memory units from the full object
299 to the pointed-to object -- that is, the value `embedded_offset' would
300 have if we followed the pointer and fetched the complete object.
301 (I don't really see the point. Why not just determine the
302 run-time type when you indirect, and avoid the special case? The
303 contents don't matter until you indirect anyway.)
305 If we're not doing anything fancy, `enclosing_type' is equal to
306 `type', and `embedded_offset' is zero, so everything works
308 struct type *enclosing_type;
309 LONGEST embedded_offset;
310 LONGEST pointed_to_offset;
312 /* Values are stored in a chain, so that they can be deleted easily
313 over calls to the inferior. Values assigned to internal
314 variables, put into the value history or exposed to Python are
315 taken off this list. */
318 /* Actual contents of the value. Target byte-order. NULL or not
319 valid if lazy is nonzero. */
322 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
323 rather than available, since the common and default case is for a
324 value to be available. This is filled in at value read time.
325 The unavailable ranges are tracked in bits. Note that a contents
326 bit that has been optimized out doesn't really exist in the
327 program, so it can't be marked unavailable either. */
328 VEC(range_s) *unavailable;
330 /* Likewise, but for optimized out contents (a chunk of the value of
331 a variable that does not actually exist in the program). If LVAL
332 is lval_register, this is a register ($pc, $sp, etc., never a
333 program variable) that has not been saved in the frame. Not
334 saved registers and optimized-out program variables values are
335 treated pretty much the same, except not-saved registers have a
336 different string representation and related error strings. */
337 VEC(range_s) *optimized_out;
343 get_value_arch (const struct value *value)
345 return get_type_arch (value_type (value));
349 value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
351 gdb_assert (!value->lazy);
353 return !ranges_contain (value->unavailable, offset, length);
357 value_bytes_available (const struct value *value,
358 LONGEST offset, LONGEST length)
360 return value_bits_available (value,
361 offset * TARGET_CHAR_BIT,
362 length * TARGET_CHAR_BIT);
366 value_bits_any_optimized_out (const struct value *value, int bit_offset, int bit_length)
368 gdb_assert (!value->lazy);
370 return ranges_contain (value->optimized_out, bit_offset, bit_length);
374 value_entirely_available (struct value *value)
376 /* We can only tell whether the whole value is available when we try
379 value_fetch_lazy (value);
381 if (VEC_empty (range_s, value->unavailable))
386 /* Returns true if VALUE is entirely covered by RANGES. If the value
387 is lazy, it'll be read now. Note that RANGE is a pointer to
388 pointer because reading the value might change *RANGE. */
391 value_entirely_covered_by_range_vector (struct value *value,
392 VEC(range_s) **ranges)
394 /* We can only tell whether the whole value is optimized out /
395 unavailable when we try to read it. */
397 value_fetch_lazy (value);
399 if (VEC_length (range_s, *ranges) == 1)
401 struct range *t = VEC_index (range_s, *ranges, 0);
404 && t->length == (TARGET_CHAR_BIT
405 * TYPE_LENGTH (value_enclosing_type (value))))
413 value_entirely_unavailable (struct value *value)
415 return value_entirely_covered_by_range_vector (value, &value->unavailable);
419 value_entirely_optimized_out (struct value *value)
421 return value_entirely_covered_by_range_vector (value, &value->optimized_out);
424 /* Insert into the vector pointed to by VECTORP the bit range starting of
425 OFFSET bits, and extending for the next LENGTH bits. */
428 insert_into_bit_range_vector (VEC(range_s) **vectorp,
429 LONGEST offset, LONGEST length)
434 /* Insert the range sorted. If there's overlap or the new range
435 would be contiguous with an existing range, merge. */
437 newr.offset = offset;
438 newr.length = length;
440 /* Do a binary search for the position the given range would be
441 inserted if we only considered the starting OFFSET of ranges.
442 Call that position I. Since we also have LENGTH to care for
443 (this is a range afterall), we need to check if the _previous_
444 range overlaps the I range. E.g., calling R the new range:
446 #1 - overlaps with previous
450 |---| |---| |------| ... |--|
455 In the case #1 above, the binary search would return `I=1',
456 meaning, this OFFSET should be inserted at position 1, and the
457 current position 1 should be pushed further (and become 2). But,
458 note that `0' overlaps with R, so we want to merge them.
460 A similar consideration needs to be taken if the new range would
461 be contiguous with the previous range:
463 #2 - contiguous with previous
467 |--| |---| |------| ... |--|
472 If there's no overlap with the previous range, as in:
474 #3 - not overlapping and not contiguous
478 |--| |---| |------| ... |--|
485 #4 - R is the range with lowest offset
489 |--| |---| |------| ... |--|
494 ... we just push the new range to I.
496 All the 4 cases above need to consider that the new range may
497 also overlap several of the ranges that follow, or that R may be
498 contiguous with the following range, and merge. E.g.,
500 #5 - overlapping following ranges
503 |------------------------|
504 |--| |---| |------| ... |--|
513 |--| |---| |------| ... |--|
520 i = VEC_lower_bound (range_s, *vectorp, &newr, range_lessthan);
523 struct range *bef = VEC_index (range_s, *vectorp, i - 1);
525 if (ranges_overlap (bef->offset, bef->length, offset, length))
528 ULONGEST l = std::min (bef->offset, offset);
529 ULONGEST h = std::max (bef->offset + bef->length, offset + length);
535 else if (offset == bef->offset + bef->length)
538 bef->length += length;
544 VEC_safe_insert (range_s, *vectorp, i, &newr);
550 VEC_safe_insert (range_s, *vectorp, i, &newr);
553 /* Check whether the ranges following the one we've just added or
554 touched can be folded in (#5 above). */
555 if (i + 1 < VEC_length (range_s, *vectorp))
562 /* Get the range we just touched. */
563 t = VEC_index (range_s, *vectorp, i);
567 for (; VEC_iterate (range_s, *vectorp, i, r); i++)
568 if (r->offset <= t->offset + t->length)
572 l = std::min (t->offset, r->offset);
573 h = std::max (t->offset + t->length, r->offset + r->length);
582 /* If we couldn't merge this one, we won't be able to
583 merge following ones either, since the ranges are
584 always sorted by OFFSET. */
589 VEC_block_remove (range_s, *vectorp, next, removed);
594 mark_value_bits_unavailable (struct value *value,
595 LONGEST offset, LONGEST length)
597 insert_into_bit_range_vector (&value->unavailable, offset, length);
601 mark_value_bytes_unavailable (struct value *value,
602 LONGEST offset, LONGEST length)
604 mark_value_bits_unavailable (value,
605 offset * TARGET_CHAR_BIT,
606 length * TARGET_CHAR_BIT);
609 /* Find the first range in RANGES that overlaps the range defined by
610 OFFSET and LENGTH, starting at element POS in the RANGES vector,
611 Returns the index into RANGES where such overlapping range was
612 found, or -1 if none was found. */
615 find_first_range_overlap (VEC(range_s) *ranges, int pos,
616 LONGEST offset, LONGEST length)
621 for (i = pos; VEC_iterate (range_s, ranges, i, r); i++)
622 if (ranges_overlap (r->offset, r->length, offset, length))
628 /* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
629 PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
632 It must always be the case that:
633 OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
635 It is assumed that memory can be accessed from:
636 PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
638 PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
639 / TARGET_CHAR_BIT) */
641 memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
642 const gdb_byte *ptr2, size_t offset2_bits,
645 gdb_assert (offset1_bits % TARGET_CHAR_BIT
646 == offset2_bits % TARGET_CHAR_BIT);
648 if (offset1_bits % TARGET_CHAR_BIT != 0)
651 gdb_byte mask, b1, b2;
653 /* The offset from the base pointers PTR1 and PTR2 is not a complete
654 number of bytes. A number of bits up to either the next exact
655 byte boundary, or LENGTH_BITS (which ever is sooner) will be
657 bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
658 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
659 mask = (1 << bits) - 1;
661 if (length_bits < bits)
663 mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
667 /* Now load the two bytes and mask off the bits we care about. */
668 b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
669 b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
674 /* Now update the length and offsets to take account of the bits
675 we've just compared. */
677 offset1_bits += bits;
678 offset2_bits += bits;
681 if (length_bits % TARGET_CHAR_BIT != 0)
685 gdb_byte mask, b1, b2;
687 /* The length is not an exact number of bytes. After the previous
688 IF.. block then the offsets are byte aligned, or the
689 length is zero (in which case this code is not reached). Compare
690 a number of bits at the end of the region, starting from an exact
692 bits = length_bits % TARGET_CHAR_BIT;
693 o1 = offset1_bits + length_bits - bits;
694 o2 = offset2_bits + length_bits - bits;
696 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
697 mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
699 gdb_assert (o1 % TARGET_CHAR_BIT == 0);
700 gdb_assert (o2 % TARGET_CHAR_BIT == 0);
702 b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
703 b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
713 /* We've now taken care of any stray "bits" at the start, or end of
714 the region to compare, the remainder can be covered with a simple
716 gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
717 gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
718 gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
720 return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
721 ptr2 + offset2_bits / TARGET_CHAR_BIT,
722 length_bits / TARGET_CHAR_BIT);
725 /* Length is zero, regions match. */
729 /* Helper struct for find_first_range_overlap_and_match and
730 value_contents_bits_eq. Keep track of which slot of a given ranges
731 vector have we last looked at. */
733 struct ranges_and_idx
736 VEC(range_s) *ranges;
738 /* The range we've last found in RANGES. Given ranges are sorted,
739 we can start the next lookup here. */
743 /* Helper function for value_contents_bits_eq. Compare LENGTH bits of
744 RP1's ranges starting at OFFSET1 bits with LENGTH bits of RP2's
745 ranges starting at OFFSET2 bits. Return true if the ranges match
746 and fill in *L and *H with the overlapping window relative to
747 (both) OFFSET1 or OFFSET2. */
750 find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
751 struct ranges_and_idx *rp2,
752 LONGEST offset1, LONGEST offset2,
753 LONGEST length, ULONGEST *l, ULONGEST *h)
755 rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
757 rp2->idx = find_first_range_overlap (rp2->ranges, rp2->idx,
760 if (rp1->idx == -1 && rp2->idx == -1)
766 else if (rp1->idx == -1 || rp2->idx == -1)
774 r1 = VEC_index (range_s, rp1->ranges, rp1->idx);
775 r2 = VEC_index (range_s, rp2->ranges, rp2->idx);
777 /* Get the unavailable windows intersected by the incoming
778 ranges. The first and last ranges that overlap the argument
779 range may be wider than said incoming arguments ranges. */
780 l1 = std::max (offset1, r1->offset);
781 h1 = std::min (offset1 + length, r1->offset + r1->length);
783 l2 = std::max (offset2, r2->offset);
784 h2 = std::min (offset2 + length, offset2 + r2->length);
786 /* Make them relative to the respective start offsets, so we can
787 compare them for equality. */
794 /* Different ranges, no match. */
795 if (l1 != l2 || h1 != h2)
804 /* Helper function for value_contents_eq. The only difference is that
805 this function is bit rather than byte based.
807 Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits
808 with LENGTH bits of VAL2's contents starting at OFFSET2 bits.
809 Return true if the available bits match. */
812 value_contents_bits_eq (const struct value *val1, int offset1,
813 const struct value *val2, int offset2,
816 /* Each array element corresponds to a ranges source (unavailable,
817 optimized out). '1' is for VAL1, '2' for VAL2. */
818 struct ranges_and_idx rp1[2], rp2[2];
820 /* See function description in value.h. */
821 gdb_assert (!val1->lazy && !val2->lazy);
823 /* We shouldn't be trying to compare past the end of the values. */
824 gdb_assert (offset1 + length
825 <= TYPE_LENGTH (val1->enclosing_type) * TARGET_CHAR_BIT);
826 gdb_assert (offset2 + length
827 <= TYPE_LENGTH (val2->enclosing_type) * TARGET_CHAR_BIT);
829 memset (&rp1, 0, sizeof (rp1));
830 memset (&rp2, 0, sizeof (rp2));
831 rp1[0].ranges = val1->unavailable;
832 rp2[0].ranges = val2->unavailable;
833 rp1[1].ranges = val1->optimized_out;
834 rp2[1].ranges = val2->optimized_out;
838 ULONGEST l = 0, h = 0; /* init for gcc -Wall */
841 for (i = 0; i < 2; i++)
843 ULONGEST l_tmp, h_tmp;
845 /* The contents only match equal if the invalid/unavailable
846 contents ranges match as well. */
847 if (!find_first_range_overlap_and_match (&rp1[i], &rp2[i],
848 offset1, offset2, length,
852 /* We're interested in the lowest/first range found. */
853 if (i == 0 || l_tmp < l)
860 /* Compare the available/valid contents. */
861 if (memcmp_with_bit_offsets (val1->contents, offset1,
862 val2->contents, offset2, l) != 0)
874 value_contents_eq (const struct value *val1, LONGEST offset1,
875 const struct value *val2, LONGEST offset2,
878 return value_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
879 val2, offset2 * TARGET_CHAR_BIT,
880 length * TARGET_CHAR_BIT);
884 /* The value-history records all the values printed
885 by print commands during this session. Each chunk
886 records 60 consecutive values. The first chunk on
887 the chain records the most recent values.
888 The total number of values is in value_history_count. */
890 #define VALUE_HISTORY_CHUNK 60
892 struct value_history_chunk
894 struct value_history_chunk *next;
895 struct value *values[VALUE_HISTORY_CHUNK];
898 /* Chain of chunks now in use. */
900 static struct value_history_chunk *value_history_chain;
902 static int value_history_count; /* Abs number of last entry stored. */
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 struct value *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 = XCNEW (struct value);
929 val->contents = NULL;
930 val->next = all_values;
933 val->enclosing_type = type;
934 VALUE_LVAL (val) = not_lval;
935 val->location.address = 0;
940 val->embedded_offset = 0;
941 val->pointed_to_offset = 0;
943 val->initialized = 1; /* Default to initialized. */
945 /* Values start out on the all_values chain. */
946 val->reference_count = 1;
951 /* The maximum size, in bytes, that GDB will try to allocate for a value.
952 The initial value of 64k was not selected for any specific reason, it is
953 just a reasonable starting point. */
955 static int max_value_size = 65536; /* 64k bytes */
957 /* It is critical that the MAX_VALUE_SIZE is at least as big as the size of
958 LONGEST, otherwise GDB will not be able to parse integer values from the
959 CLI; for example if the MAX_VALUE_SIZE could be set to 1 then GDB would
960 be unable to parse "set max-value-size 2".
962 As we want a consistent GDB experience across hosts with different sizes
963 of LONGEST, this arbitrary minimum value was selected, so long as this
964 is bigger than LONGEST on all GDB supported hosts we're fine. */
966 #define MIN_VALUE_FOR_MAX_VALUE_SIZE 16
967 gdb_static_assert (sizeof (LONGEST) <= MIN_VALUE_FOR_MAX_VALUE_SIZE);
969 /* Implement the "set max-value-size" command. */
972 set_max_value_size (const char *args, int from_tty,
973 struct cmd_list_element *c)
975 gdb_assert (max_value_size == -1 || max_value_size >= 0);
977 if (max_value_size > -1 && max_value_size < MIN_VALUE_FOR_MAX_VALUE_SIZE)
979 max_value_size = MIN_VALUE_FOR_MAX_VALUE_SIZE;
980 error (_("max-value-size set too low, increasing to %d bytes"),
985 /* Implement the "show max-value-size" command. */
988 show_max_value_size (struct ui_file *file, int from_tty,
989 struct cmd_list_element *c, const char *value)
991 if (max_value_size == -1)
992 fprintf_filtered (file, _("Maximum value size is unlimited.\n"));
994 fprintf_filtered (file, _("Maximum value size is %d bytes.\n"),
998 /* Called before we attempt to allocate or reallocate a buffer for the
999 contents of a value. TYPE is the type of the value for which we are
1000 allocating the buffer. If the buffer is too large (based on the user
1001 controllable setting) then throw an error. If this function returns
1002 then we should attempt to allocate the buffer. */
1005 check_type_length_before_alloc (const struct type *type)
1007 unsigned int length = TYPE_LENGTH (type);
1009 if (max_value_size > -1 && length > max_value_size)
1011 if (TYPE_NAME (type) != NULL)
1012 error (_("value of type `%s' requires %u bytes, which is more "
1013 "than max-value-size"), TYPE_NAME (type), length);
1015 error (_("value requires %u bytes, which is more than "
1016 "max-value-size"), length);
1020 /* Allocate the contents of VAL if it has not been allocated yet. */
1023 allocate_value_contents (struct value *val)
1027 check_type_length_before_alloc (val->enclosing_type);
1029 = (gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type));
1033 /* Allocate a value and its contents for type TYPE. */
1036 allocate_value (struct type *type)
1038 struct value *val = allocate_value_lazy (type);
1040 allocate_value_contents (val);
1045 /* Allocate a value that has the correct length
1046 for COUNT repetitions of type TYPE. */
1049 allocate_repeat_value (struct type *type, int count)
1051 int low_bound = current_language->string_lower_bound; /* ??? */
1052 /* FIXME-type-allocation: need a way to free this type when we are
1054 struct type *array_type
1055 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
1057 return allocate_value (array_type);
1061 allocate_computed_value (struct type *type,
1062 const struct lval_funcs *funcs,
1065 struct value *v = allocate_value_lazy (type);
1067 VALUE_LVAL (v) = lval_computed;
1068 v->location.computed.funcs = funcs;
1069 v->location.computed.closure = closure;
1074 /* Allocate NOT_LVAL value for type TYPE being OPTIMIZED_OUT. */
1077 allocate_optimized_out_value (struct type *type)
1079 struct value *retval = allocate_value_lazy (type);
1081 mark_value_bytes_optimized_out (retval, 0, TYPE_LENGTH (type));
1082 set_value_lazy (retval, 0);
1086 /* Accessor methods. */
1089 value_next (const struct value *value)
1095 value_type (const struct value *value)
1100 deprecated_set_value_type (struct value *value, struct type *type)
1106 value_offset (const struct value *value)
1108 return value->offset;
1111 set_value_offset (struct value *value, LONGEST offset)
1113 value->offset = offset;
1117 value_bitpos (const struct value *value)
1119 return value->bitpos;
1122 set_value_bitpos (struct value *value, LONGEST bit)
1124 value->bitpos = bit;
1128 value_bitsize (const struct value *value)
1130 return value->bitsize;
1133 set_value_bitsize (struct value *value, LONGEST bit)
1135 value->bitsize = bit;
1139 value_parent (const struct value *value)
1141 return value->parent;
1147 set_value_parent (struct value *value, struct value *parent)
1149 struct value *old = value->parent;
1151 value->parent = parent;
1153 value_incref (parent);
1158 value_contents_raw (struct value *value)
1160 struct gdbarch *arch = get_value_arch (value);
1161 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1163 allocate_value_contents (value);
1164 return value->contents + value->embedded_offset * unit_size;
1168 value_contents_all_raw (struct value *value)
1170 allocate_value_contents (value);
1171 return value->contents;
1175 value_enclosing_type (const struct value *value)
1177 return value->enclosing_type;
1180 /* Look at value.h for description. */
1183 value_actual_type (struct value *value, int resolve_simple_types,
1184 int *real_type_found)
1186 struct value_print_options opts;
1187 struct type *result;
1189 get_user_print_options (&opts);
1191 if (real_type_found)
1192 *real_type_found = 0;
1193 result = value_type (value);
1194 if (opts.objectprint)
1196 /* If result's target type is TYPE_CODE_STRUCT, proceed to
1197 fetch its rtti type. */
1198 if ((TYPE_CODE (result) == TYPE_CODE_PTR || TYPE_IS_REFERENCE (result))
1199 && TYPE_CODE (check_typedef (TYPE_TARGET_TYPE (result)))
1201 && !value_optimized_out (value))
1203 struct type *real_type;
1205 real_type = value_rtti_indirect_type (value, NULL, NULL, NULL);
1208 if (real_type_found)
1209 *real_type_found = 1;
1213 else if (resolve_simple_types)
1215 if (real_type_found)
1216 *real_type_found = 1;
1217 result = value_enclosing_type (value);
1225 error_value_optimized_out (void)
1227 error (_("value has been optimized out"));
1231 require_not_optimized_out (const struct value *value)
1233 if (!VEC_empty (range_s, value->optimized_out))
1235 if (value->lval == lval_register)
1236 error (_("register has not been saved in frame"));
1238 error_value_optimized_out ();
1243 require_available (const struct value *value)
1245 if (!VEC_empty (range_s, value->unavailable))
1246 throw_error (NOT_AVAILABLE_ERROR, _("value is not available"));
1250 value_contents_for_printing (struct value *value)
1253 value_fetch_lazy (value);
1254 return value->contents;
1258 value_contents_for_printing_const (const struct value *value)
1260 gdb_assert (!value->lazy);
1261 return value->contents;
1265 value_contents_all (struct value *value)
1267 const gdb_byte *result = value_contents_for_printing (value);
1268 require_not_optimized_out (value);
1269 require_available (value);
1273 /* Copy ranges in SRC_RANGE that overlap [SRC_BIT_OFFSET,
1274 SRC_BIT_OFFSET+BIT_LENGTH) ranges into *DST_RANGE, adjusted. */
1277 ranges_copy_adjusted (VEC (range_s) **dst_range, int dst_bit_offset,
1278 VEC (range_s) *src_range, int src_bit_offset,
1284 for (i = 0; VEC_iterate (range_s, src_range, i, r); i++)
1288 l = std::max (r->offset, (LONGEST) src_bit_offset);
1289 h = std::min (r->offset + r->length,
1290 (LONGEST) src_bit_offset + bit_length);
1293 insert_into_bit_range_vector (dst_range,
1294 dst_bit_offset + (l - src_bit_offset),
1299 /* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
1300 SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
1303 value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
1304 const struct value *src, int src_bit_offset,
1307 ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
1308 src->unavailable, src_bit_offset,
1310 ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
1311 src->optimized_out, src_bit_offset,
1315 /* Copy LENGTH target addressable memory units of SRC value's (all) contents
1316 (value_contents_all) starting at SRC_OFFSET, into DST value's (all)
1317 contents, starting at DST_OFFSET. If unavailable contents are
1318 being copied from SRC, the corresponding DST contents are marked
1319 unavailable accordingly. Neither DST nor SRC may be lazy
1322 It is assumed the contents of DST in the [DST_OFFSET,
1323 DST_OFFSET+LENGTH) range are wholly available. */
1326 value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
1327 struct value *src, LONGEST src_offset, LONGEST length)
1329 LONGEST src_bit_offset, dst_bit_offset, bit_length;
1330 struct gdbarch *arch = get_value_arch (src);
1331 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1333 /* A lazy DST would make that this copy operation useless, since as
1334 soon as DST's contents were un-lazied (by a later value_contents
1335 call, say), the contents would be overwritten. A lazy SRC would
1336 mean we'd be copying garbage. */
1337 gdb_assert (!dst->lazy && !src->lazy);
1339 /* The overwritten DST range gets unavailability ORed in, not
1340 replaced. Make sure to remember to implement replacing if it
1341 turns out actually necessary. */
1342 gdb_assert (value_bytes_available (dst, dst_offset, length));
1343 gdb_assert (!value_bits_any_optimized_out (dst,
1344 TARGET_CHAR_BIT * dst_offset,
1345 TARGET_CHAR_BIT * length));
1347 /* Copy the data. */
1348 memcpy (value_contents_all_raw (dst) + dst_offset * unit_size,
1349 value_contents_all_raw (src) + src_offset * unit_size,
1350 length * unit_size);
1352 /* Copy the meta-data, adjusted. */
1353 src_bit_offset = src_offset * unit_size * HOST_CHAR_BIT;
1354 dst_bit_offset = dst_offset * unit_size * HOST_CHAR_BIT;
1355 bit_length = length * unit_size * HOST_CHAR_BIT;
1357 value_ranges_copy_adjusted (dst, dst_bit_offset,
1358 src, src_bit_offset,
1362 /* Copy LENGTH bytes of SRC value's (all) contents
1363 (value_contents_all) starting at SRC_OFFSET byte, into DST value's
1364 (all) contents, starting at DST_OFFSET. If unavailable contents
1365 are being copied from SRC, the corresponding DST contents are
1366 marked unavailable accordingly. DST must not be lazy. If SRC is
1367 lazy, it will be fetched now.
1369 It is assumed the contents of DST in the [DST_OFFSET,
1370 DST_OFFSET+LENGTH) range are wholly available. */
1373 value_contents_copy (struct value *dst, LONGEST dst_offset,
1374 struct value *src, LONGEST src_offset, LONGEST length)
1377 value_fetch_lazy (src);
1379 value_contents_copy_raw (dst, dst_offset, src, src_offset, length);
1383 value_lazy (const struct value *value)
1389 set_value_lazy (struct value *value, int val)
1395 value_stack (const struct value *value)
1397 return value->stack;
1401 set_value_stack (struct value *value, int val)
1407 value_contents (struct value *value)
1409 const gdb_byte *result = value_contents_writeable (value);
1410 require_not_optimized_out (value);
1411 require_available (value);
1416 value_contents_writeable (struct value *value)
1419 value_fetch_lazy (value);
1420 return value_contents_raw (value);
1424 value_optimized_out (struct value *value)
1426 /* We can only know if a value is optimized out once we have tried to
1428 if (VEC_empty (range_s, value->optimized_out) && value->lazy)
1432 value_fetch_lazy (value);
1434 CATCH (ex, RETURN_MASK_ERROR)
1436 /* Fall back to checking value->optimized_out. */
1441 return !VEC_empty (range_s, value->optimized_out);
1444 /* Mark contents of VALUE as optimized out, starting at OFFSET bytes, and
1445 the following LENGTH bytes. */
1448 mark_value_bytes_optimized_out (struct value *value, int offset, int length)
1450 mark_value_bits_optimized_out (value,
1451 offset * TARGET_CHAR_BIT,
1452 length * TARGET_CHAR_BIT);
1458 mark_value_bits_optimized_out (struct value *value,
1459 LONGEST offset, LONGEST length)
1461 insert_into_bit_range_vector (&value->optimized_out, offset, length);
1465 value_bits_synthetic_pointer (const struct value *value,
1466 LONGEST offset, LONGEST length)
1468 if (value->lval != lval_computed
1469 || !value->location.computed.funcs->check_synthetic_pointer)
1471 return value->location.computed.funcs->check_synthetic_pointer (value,
1477 value_embedded_offset (const struct value *value)
1479 return value->embedded_offset;
1483 set_value_embedded_offset (struct value *value, LONGEST val)
1485 value->embedded_offset = val;
1489 value_pointed_to_offset (const struct value *value)
1491 return value->pointed_to_offset;
1495 set_value_pointed_to_offset (struct value *value, LONGEST val)
1497 value->pointed_to_offset = val;
1500 const struct lval_funcs *
1501 value_computed_funcs (const struct value *v)
1503 gdb_assert (value_lval_const (v) == lval_computed);
1505 return v->location.computed.funcs;
1509 value_computed_closure (const struct value *v)
1511 gdb_assert (v->lval == lval_computed);
1513 return v->location.computed.closure;
1517 deprecated_value_lval_hack (struct value *value)
1519 return &value->lval;
1523 value_lval_const (const struct value *value)
1529 value_address (const struct value *value)
1531 if (value->lval != lval_memory)
1533 if (value->parent != NULL)
1534 return value_address (value->parent) + value->offset;
1535 if (NULL != TYPE_DATA_LOCATION (value_type (value)))
1537 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (value_type (value)));
1538 return TYPE_DATA_LOCATION_ADDR (value_type (value));
1541 return value->location.address + value->offset;
1545 value_raw_address (const struct value *value)
1547 if (value->lval != lval_memory)
1549 return value->location.address;
1553 set_value_address (struct value *value, CORE_ADDR addr)
1555 gdb_assert (value->lval == lval_memory);
1556 value->location.address = addr;
1559 struct internalvar **
1560 deprecated_value_internalvar_hack (struct value *value)
1562 return &value->location.internalvar;
1566 deprecated_value_next_frame_id_hack (struct value *value)
1568 gdb_assert (value->lval == lval_register);
1569 return &value->location.reg.next_frame_id;
1573 deprecated_value_regnum_hack (struct value *value)
1575 gdb_assert (value->lval == lval_register);
1576 return &value->location.reg.regnum;
1580 deprecated_value_modifiable (const struct value *value)
1582 return value->modifiable;
1585 /* Return a mark in the value chain. All values allocated after the
1586 mark is obtained (except for those released) are subject to being freed
1587 if a subsequent value_free_to_mark is passed the mark. */
1594 /* Take a reference to VAL. VAL will not be deallocated until all
1595 references are released. */
1598 value_incref (struct value *val)
1600 val->reference_count++;
1604 /* Release a reference to VAL, which was acquired with value_incref.
1605 This function is also called to deallocate values from the value
1609 value_decref (struct value *val)
1613 gdb_assert (val->reference_count > 0);
1614 val->reference_count--;
1615 if (val->reference_count > 0)
1618 /* If there's an associated parent value, drop our reference to
1620 if (val->parent != NULL)
1621 value_decref (val->parent);
1623 if (VALUE_LVAL (val) == lval_computed)
1625 const struct lval_funcs *funcs = val->location.computed.funcs;
1627 if (funcs->free_closure)
1628 funcs->free_closure (val);
1630 else if (VALUE_LVAL (val) == lval_xcallable)
1631 delete val->location.xm_worker;
1633 xfree (val->contents);
1634 VEC_free (range_s, val->unavailable);
1639 /* Free all values allocated since MARK was obtained by value_mark
1640 (except for those released). */
1642 value_free_to_mark (const struct value *mark)
1647 for (val = all_values; val && val != mark; val = next)
1656 /* Free all the values that have been allocated (except for those released).
1657 Call after each command, successful or not.
1658 In practice this is called before each command, which is sufficient. */
1661 free_all_values (void)
1666 for (val = all_values; val; val = next)
1676 /* Frees all the elements in a chain of values. */
1679 free_value_chain (struct value *v)
1685 next = value_next (v);
1690 /* Remove VAL from the chain all_values
1691 so it will not be freed automatically. */
1694 release_value (struct value *val)
1697 bool released = false;
1700 return value_ref_ptr ();
1702 if (all_values == val)
1704 all_values = val->next;
1710 for (v = all_values; v; v = v->next)
1714 v->next = val->next;
1724 /* We must always return an owned reference. Normally this
1725 happens because we transfer the reference from the value
1726 chain, but in this case the value was not on the chain. */
1730 return value_ref_ptr (val);
1733 /* Release all values up to mark */
1735 value_release_to_mark (const struct value *mark)
1740 for (val = next = all_values; next; next = next->next)
1742 if (next->next == mark)
1744 all_values = next->next;
1754 /* Return a copy of the value ARG.
1755 It contains the same contents, for same memory address,
1756 but it's a different block of storage. */
1759 value_copy (struct value *arg)
1761 struct type *encl_type = value_enclosing_type (arg);
1764 if (value_lazy (arg))
1765 val = allocate_value_lazy (encl_type);
1767 val = allocate_value (encl_type);
1768 val->type = arg->type;
1769 VALUE_LVAL (val) = VALUE_LVAL (arg);
1770 val->location = arg->location;
1771 val->offset = arg->offset;
1772 val->bitpos = arg->bitpos;
1773 val->bitsize = arg->bitsize;
1774 val->lazy = arg->lazy;
1775 val->embedded_offset = value_embedded_offset (arg);
1776 val->pointed_to_offset = arg->pointed_to_offset;
1777 val->modifiable = arg->modifiable;
1778 if (!value_lazy (val))
1780 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
1781 TYPE_LENGTH (value_enclosing_type (arg)));
1784 val->unavailable = VEC_copy (range_s, arg->unavailable);
1785 val->optimized_out = VEC_copy (range_s, arg->optimized_out);
1786 set_value_parent (val, arg->parent);
1787 if (VALUE_LVAL (val) == lval_computed)
1789 const struct lval_funcs *funcs = val->location.computed.funcs;
1791 if (funcs->copy_closure)
1792 val->location.computed.closure = funcs->copy_closure (val);
1797 /* Return a "const" and/or "volatile" qualified version of the value V.
1798 If CNST is true, then the returned value will be qualified with
1800 if VOLTL is true, then the returned value will be qualified with
1804 make_cv_value (int cnst, int voltl, struct value *v)
1806 struct type *val_type = value_type (v);
1807 struct type *enclosing_type = value_enclosing_type (v);
1808 struct value *cv_val = value_copy (v);
1810 deprecated_set_value_type (cv_val,
1811 make_cv_type (cnst, voltl, val_type, NULL));
1812 set_value_enclosing_type (cv_val,
1813 make_cv_type (cnst, voltl, enclosing_type, NULL));
1818 /* Return a version of ARG that is non-lvalue. */
1821 value_non_lval (struct value *arg)
1823 if (VALUE_LVAL (arg) != not_lval)
1825 struct type *enc_type = value_enclosing_type (arg);
1826 struct value *val = allocate_value (enc_type);
1828 memcpy (value_contents_all_raw (val), value_contents_all (arg),
1829 TYPE_LENGTH (enc_type));
1830 val->type = arg->type;
1831 set_value_embedded_offset (val, value_embedded_offset (arg));
1832 set_value_pointed_to_offset (val, value_pointed_to_offset (arg));
1838 /* Write contents of V at ADDR and set its lval type to be LVAL_MEMORY. */
1841 value_force_lval (struct value *v, CORE_ADDR addr)
1843 gdb_assert (VALUE_LVAL (v) == not_lval);
1845 write_memory (addr, value_contents_raw (v), TYPE_LENGTH (value_type (v)));
1846 v->lval = lval_memory;
1847 v->location.address = addr;
1851 set_value_component_location (struct value *component,
1852 const struct value *whole)
1856 gdb_assert (whole->lval != lval_xcallable);
1858 if (whole->lval == lval_internalvar)
1859 VALUE_LVAL (component) = lval_internalvar_component;
1861 VALUE_LVAL (component) = whole->lval;
1863 component->location = whole->location;
1864 if (whole->lval == lval_computed)
1866 const struct lval_funcs *funcs = whole->location.computed.funcs;
1868 if (funcs->copy_closure)
1869 component->location.computed.closure = funcs->copy_closure (whole);
1872 /* If type has a dynamic resolved location property
1873 update it's value address. */
1874 type = value_type (whole);
1875 if (NULL != TYPE_DATA_LOCATION (type)
1876 && TYPE_DATA_LOCATION_KIND (type) == PROP_CONST)
1877 set_value_address (component, TYPE_DATA_LOCATION_ADDR (type));
1880 /* Access to the value history. */
1882 /* Record a new value in the value history.
1883 Returns the absolute history index of the entry. */
1886 record_latest_value (struct value *val)
1890 /* We don't want this value to have anything to do with the inferior anymore.
1891 In particular, "set $1 = 50" should not affect the variable from which
1892 the value was taken, and fast watchpoints should be able to assume that
1893 a value on the value history never changes. */
1894 if (value_lazy (val))
1895 value_fetch_lazy (val);
1896 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1897 from. This is a bit dubious, because then *&$1 does not just return $1
1898 but the current contents of that location. c'est la vie... */
1899 val->modifiable = 0;
1901 /* Here we treat value_history_count as origin-zero
1902 and applying to the value being stored now. */
1904 i = value_history_count % VALUE_HISTORY_CHUNK;
1907 struct value_history_chunk *newobj = XCNEW (struct value_history_chunk);
1909 newobj->next = value_history_chain;
1910 value_history_chain = newobj;
1913 value_history_chain->values[i] = release_value (val).release ();
1915 /* Now we regard value_history_count as origin-one
1916 and applying to the value just stored. */
1918 return ++value_history_count;
1921 /* Return a copy of the value in the history with sequence number NUM. */
1924 access_value_history (int num)
1926 struct value_history_chunk *chunk;
1931 absnum += value_history_count;
1936 error (_("The history is empty."));
1938 error (_("There is only one value in the history."));
1940 error (_("History does not go back to $$%d."), -num);
1942 if (absnum > value_history_count)
1943 error (_("History has not yet reached $%d."), absnum);
1947 /* Now absnum is always absolute and origin zero. */
1949 chunk = value_history_chain;
1950 for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK
1951 - absnum / VALUE_HISTORY_CHUNK;
1953 chunk = chunk->next;
1955 return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
1959 show_values (const char *num_exp, int from_tty)
1967 /* "show values +" should print from the stored position.
1968 "show values <exp>" should print around value number <exp>. */
1969 if (num_exp[0] != '+' || num_exp[1] != '\0')
1970 num = parse_and_eval_long (num_exp) - 5;
1974 /* "show values" means print the last 10 values. */
1975 num = value_history_count - 9;
1981 for (i = num; i < num + 10 && i <= value_history_count; i++)
1983 struct value_print_options opts;
1985 val = access_value_history (i);
1986 printf_filtered (("$%d = "), i);
1987 get_user_print_options (&opts);
1988 value_print (val, gdb_stdout, &opts);
1989 printf_filtered (("\n"));
1992 /* The next "show values +" should start after what we just printed. */
1995 /* Hitting just return after this command should do the same thing as
1996 "show values +". If num_exp is null, this is unnecessary, since
1997 "show values +" is not useful after "show values". */
1998 if (from_tty && num_exp)
1999 set_repeat_arguments ("+");
2002 enum internalvar_kind
2004 /* The internal variable is empty. */
2007 /* The value of the internal variable is provided directly as
2008 a GDB value object. */
2011 /* A fresh value is computed via a call-back routine on every
2012 access to the internal variable. */
2013 INTERNALVAR_MAKE_VALUE,
2015 /* The internal variable holds a GDB internal convenience function. */
2016 INTERNALVAR_FUNCTION,
2018 /* The variable holds an integer value. */
2019 INTERNALVAR_INTEGER,
2021 /* The variable holds a GDB-provided string. */
2025 union internalvar_data
2027 /* A value object used with INTERNALVAR_VALUE. */
2028 struct value *value;
2030 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
2033 /* The functions to call. */
2034 const struct internalvar_funcs *functions;
2036 /* The function's user-data. */
2040 /* The internal function used with INTERNALVAR_FUNCTION. */
2043 struct internal_function *function;
2044 /* True if this is the canonical name for the function. */
2048 /* An integer value used with INTERNALVAR_INTEGER. */
2051 /* If type is non-NULL, it will be used as the type to generate
2052 a value for this internal variable. If type is NULL, a default
2053 integer type for the architecture is used. */
2058 /* A string value used with INTERNALVAR_STRING. */
2062 /* Internal variables. These are variables within the debugger
2063 that hold values assigned by debugger commands.
2064 The user refers to them with a '$' prefix
2065 that does not appear in the variable names stored internally. */
2069 struct internalvar *next;
2072 /* We support various different kinds of content of an internal variable.
2073 enum internalvar_kind specifies the kind, and union internalvar_data
2074 provides the data associated with this particular kind. */
2076 enum internalvar_kind kind;
2078 union internalvar_data u;
2081 static struct internalvar *internalvars;
2083 /* If the variable does not already exist create it and give it the
2084 value given. If no value is given then the default is zero. */
2086 init_if_undefined_command (const char* args, int from_tty)
2088 struct internalvar* intvar;
2090 /* Parse the expression - this is taken from set_command(). */
2091 expression_up expr = parse_expression (args);
2093 /* Validate the expression.
2094 Was the expression an assignment?
2095 Or even an expression at all? */
2096 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
2097 error (_("Init-if-undefined requires an assignment expression."));
2099 /* Extract the variable from the parsed expression.
2100 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
2101 if (expr->elts[1].opcode != OP_INTERNALVAR)
2102 error (_("The first parameter to init-if-undefined "
2103 "should be a GDB variable."));
2104 intvar = expr->elts[2].internalvar;
2106 /* Only evaluate the expression if the lvalue is void.
2107 This may still fail if the expresssion is invalid. */
2108 if (intvar->kind == INTERNALVAR_VOID)
2109 evaluate_expression (expr.get ());
2113 /* Look up an internal variable with name NAME. NAME should not
2114 normally include a dollar sign.
2116 If the specified internal variable does not exist,
2117 the return value is NULL. */
2119 struct internalvar *
2120 lookup_only_internalvar (const char *name)
2122 struct internalvar *var;
2124 for (var = internalvars; var; var = var->next)
2125 if (strcmp (var->name, name) == 0)
2131 /* Complete NAME by comparing it to the names of internal
2135 complete_internalvar (completion_tracker &tracker, const char *name)
2137 struct internalvar *var;
2140 len = strlen (name);
2142 for (var = internalvars; var; var = var->next)
2143 if (strncmp (var->name, name, len) == 0)
2145 gdb::unique_xmalloc_ptr<char> copy (xstrdup (var->name));
2147 tracker.add_completion (std::move (copy));
2151 /* Create an internal variable with name NAME and with a void value.
2152 NAME should not normally include a dollar sign. */
2154 struct internalvar *
2155 create_internalvar (const char *name)
2157 struct internalvar *var = XNEW (struct internalvar);
2159 var->name = concat (name, (char *)NULL);
2160 var->kind = INTERNALVAR_VOID;
2161 var->next = internalvars;
2166 /* Create an internal variable with name NAME and register FUN as the
2167 function that value_of_internalvar uses to create a value whenever
2168 this variable is referenced. NAME should not normally include a
2169 dollar sign. DATA is passed uninterpreted to FUN when it is
2170 called. CLEANUP, if not NULL, is called when the internal variable
2171 is destroyed. It is passed DATA as its only argument. */
2173 struct internalvar *
2174 create_internalvar_type_lazy (const char *name,
2175 const struct internalvar_funcs *funcs,
2178 struct internalvar *var = create_internalvar (name);
2180 var->kind = INTERNALVAR_MAKE_VALUE;
2181 var->u.make_value.functions = funcs;
2182 var->u.make_value.data = data;
2186 /* See documentation in value.h. */
2189 compile_internalvar_to_ax (struct internalvar *var,
2190 struct agent_expr *expr,
2191 struct axs_value *value)
2193 if (var->kind != INTERNALVAR_MAKE_VALUE
2194 || var->u.make_value.functions->compile_to_ax == NULL)
2197 var->u.make_value.functions->compile_to_ax (var, expr, value,
2198 var->u.make_value.data);
2202 /* Look up an internal variable with name NAME. NAME should not
2203 normally include a dollar sign.
2205 If the specified internal variable does not exist,
2206 one is created, with a void value. */
2208 struct internalvar *
2209 lookup_internalvar (const char *name)
2211 struct internalvar *var;
2213 var = lookup_only_internalvar (name);
2217 return create_internalvar (name);
2220 /* Return current value of internal variable VAR. For variables that
2221 are not inherently typed, use a value type appropriate for GDBARCH. */
2224 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
2227 struct trace_state_variable *tsv;
2229 /* If there is a trace state variable of the same name, assume that
2230 is what we really want to see. */
2231 tsv = find_trace_state_variable (var->name);
2234 tsv->value_known = target_get_trace_state_variable_value (tsv->number,
2236 if (tsv->value_known)
2237 val = value_from_longest (builtin_type (gdbarch)->builtin_int64,
2240 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2246 case INTERNALVAR_VOID:
2247 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2250 case INTERNALVAR_FUNCTION:
2251 val = allocate_value (builtin_type (gdbarch)->internal_fn);
2254 case INTERNALVAR_INTEGER:
2255 if (!var->u.integer.type)
2256 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
2257 var->u.integer.val);
2259 val = value_from_longest (var->u.integer.type, var->u.integer.val);
2262 case INTERNALVAR_STRING:
2263 val = value_cstring (var->u.string, strlen (var->u.string),
2264 builtin_type (gdbarch)->builtin_char);
2267 case INTERNALVAR_VALUE:
2268 val = value_copy (var->u.value);
2269 if (value_lazy (val))
2270 value_fetch_lazy (val);
2273 case INTERNALVAR_MAKE_VALUE:
2274 val = (*var->u.make_value.functions->make_value) (gdbarch, var,
2275 var->u.make_value.data);
2279 internal_error (__FILE__, __LINE__, _("bad kind"));
2282 /* Change the VALUE_LVAL to lval_internalvar so that future operations
2283 on this value go back to affect the original internal variable.
2285 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
2286 no underlying modifyable state in the internal variable.
2288 Likewise, if the variable's value is a computed lvalue, we want
2289 references to it to produce another computed lvalue, where
2290 references and assignments actually operate through the
2291 computed value's functions.
2293 This means that internal variables with computed values
2294 behave a little differently from other internal variables:
2295 assignments to them don't just replace the previous value
2296 altogether. At the moment, this seems like the behavior we
2299 if (var->kind != INTERNALVAR_MAKE_VALUE
2300 && val->lval != lval_computed)
2302 VALUE_LVAL (val) = lval_internalvar;
2303 VALUE_INTERNALVAR (val) = var;
2310 get_internalvar_integer (struct internalvar *var, LONGEST *result)
2312 if (var->kind == INTERNALVAR_INTEGER)
2314 *result = var->u.integer.val;
2318 if (var->kind == INTERNALVAR_VALUE)
2320 struct type *type = check_typedef (value_type (var->u.value));
2322 if (TYPE_CODE (type) == TYPE_CODE_INT)
2324 *result = value_as_long (var->u.value);
2333 get_internalvar_function (struct internalvar *var,
2334 struct internal_function **result)
2338 case INTERNALVAR_FUNCTION:
2339 *result = var->u.fn.function;
2348 set_internalvar_component (struct internalvar *var,
2349 LONGEST offset, LONGEST bitpos,
2350 LONGEST bitsize, struct value *newval)
2353 struct gdbarch *arch;
2358 case INTERNALVAR_VALUE:
2359 addr = value_contents_writeable (var->u.value);
2360 arch = get_value_arch (var->u.value);
2361 unit_size = gdbarch_addressable_memory_unit_size (arch);
2364 modify_field (value_type (var->u.value), addr + offset,
2365 value_as_long (newval), bitpos, bitsize);
2367 memcpy (addr + offset * unit_size, value_contents (newval),
2368 TYPE_LENGTH (value_type (newval)));
2372 /* We can never get a component of any other kind. */
2373 internal_error (__FILE__, __LINE__, _("set_internalvar_component"));
2378 set_internalvar (struct internalvar *var, struct value *val)
2380 enum internalvar_kind new_kind;
2381 union internalvar_data new_data = { 0 };
2383 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
2384 error (_("Cannot overwrite convenience function %s"), var->name);
2386 /* Prepare new contents. */
2387 switch (TYPE_CODE (check_typedef (value_type (val))))
2389 case TYPE_CODE_VOID:
2390 new_kind = INTERNALVAR_VOID;
2393 case TYPE_CODE_INTERNAL_FUNCTION:
2394 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2395 new_kind = INTERNALVAR_FUNCTION;
2396 get_internalvar_function (VALUE_INTERNALVAR (val),
2397 &new_data.fn.function);
2398 /* Copies created here are never canonical. */
2402 new_kind = INTERNALVAR_VALUE;
2403 new_data.value = value_copy (val);
2404 new_data.value->modifiable = 1;
2406 /* Force the value to be fetched from the target now, to avoid problems
2407 later when this internalvar is referenced and the target is gone or
2409 if (value_lazy (new_data.value))
2410 value_fetch_lazy (new_data.value);
2412 /* Release the value from the value chain to prevent it from being
2413 deleted by free_all_values. From here on this function should not
2414 call error () until new_data is installed into the var->u to avoid
2416 release_value (new_data.value).release ();
2418 /* Internal variables which are created from values with a dynamic
2419 location don't need the location property of the origin anymore.
2420 The resolved dynamic location is used prior then any other address
2421 when accessing the value.
2422 If we keep it, we would still refer to the origin value.
2423 Remove the location property in case it exist. */
2424 remove_dyn_prop (DYN_PROP_DATA_LOCATION, value_type (new_data.value));
2429 /* Clean up old contents. */
2430 clear_internalvar (var);
2433 var->kind = new_kind;
2435 /* End code which must not call error(). */
2439 set_internalvar_integer (struct internalvar *var, LONGEST l)
2441 /* Clean up old contents. */
2442 clear_internalvar (var);
2444 var->kind = INTERNALVAR_INTEGER;
2445 var->u.integer.type = NULL;
2446 var->u.integer.val = l;
2450 set_internalvar_string (struct internalvar *var, const char *string)
2452 /* Clean up old contents. */
2453 clear_internalvar (var);
2455 var->kind = INTERNALVAR_STRING;
2456 var->u.string = xstrdup (string);
2460 set_internalvar_function (struct internalvar *var, struct internal_function *f)
2462 /* Clean up old contents. */
2463 clear_internalvar (var);
2465 var->kind = INTERNALVAR_FUNCTION;
2466 var->u.fn.function = f;
2467 var->u.fn.canonical = 1;
2468 /* Variables installed here are always the canonical version. */
2472 clear_internalvar (struct internalvar *var)
2474 /* Clean up old contents. */
2477 case INTERNALVAR_VALUE:
2478 value_decref (var->u.value);
2481 case INTERNALVAR_STRING:
2482 xfree (var->u.string);
2485 case INTERNALVAR_MAKE_VALUE:
2486 if (var->u.make_value.functions->destroy != NULL)
2487 var->u.make_value.functions->destroy (var->u.make_value.data);
2494 /* Reset to void kind. */
2495 var->kind = INTERNALVAR_VOID;
2499 internalvar_name (const struct internalvar *var)
2504 static struct internal_function *
2505 create_internal_function (const char *name,
2506 internal_function_fn handler, void *cookie)
2508 struct internal_function *ifn = XNEW (struct internal_function);
2510 ifn->name = xstrdup (name);
2511 ifn->handler = handler;
2512 ifn->cookie = cookie;
2517 value_internal_function_name (struct value *val)
2519 struct internal_function *ifn;
2522 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2523 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
2524 gdb_assert (result);
2530 call_internal_function (struct gdbarch *gdbarch,
2531 const struct language_defn *language,
2532 struct value *func, int argc, struct value **argv)
2534 struct internal_function *ifn;
2537 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
2538 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
2539 gdb_assert (result);
2541 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
2544 /* The 'function' command. This does nothing -- it is just a
2545 placeholder to let "help function NAME" work. This is also used as
2546 the implementation of the sub-command that is created when
2547 registering an internal function. */
2549 function_command (const char *command, int from_tty)
2554 /* Clean up if an internal function's command is destroyed. */
2556 function_destroyer (struct cmd_list_element *self, void *ignore)
2558 xfree ((char *) self->name);
2559 xfree ((char *) self->doc);
2562 /* Add a new internal function. NAME is the name of the function; DOC
2563 is a documentation string describing the function. HANDLER is
2564 called when the function is invoked. COOKIE is an arbitrary
2565 pointer which is passed to HANDLER and is intended for "user
2568 add_internal_function (const char *name, const char *doc,
2569 internal_function_fn handler, void *cookie)
2571 struct cmd_list_element *cmd;
2572 struct internal_function *ifn;
2573 struct internalvar *var = lookup_internalvar (name);
2575 ifn = create_internal_function (name, handler, cookie);
2576 set_internalvar_function (var, ifn);
2578 cmd = add_cmd (xstrdup (name), no_class, function_command, (char *) doc,
2580 cmd->destroyer = function_destroyer;
2583 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
2584 prevent cycles / duplicates. */
2587 preserve_one_value (struct value *value, struct objfile *objfile,
2588 htab_t copied_types)
2590 if (TYPE_OBJFILE (value->type) == objfile)
2591 value->type = copy_type_recursive (objfile, value->type, copied_types);
2593 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
2594 value->enclosing_type = copy_type_recursive (objfile,
2595 value->enclosing_type,
2599 /* Likewise for internal variable VAR. */
2602 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
2603 htab_t copied_types)
2607 case INTERNALVAR_INTEGER:
2608 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
2610 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
2613 case INTERNALVAR_VALUE:
2614 preserve_one_value (var->u.value, objfile, copied_types);
2619 /* Update the internal variables and value history when OBJFILE is
2620 discarded; we must copy the types out of the objfile. New global types
2621 will be created for every convenience variable which currently points to
2622 this objfile's types, and the convenience variables will be adjusted to
2623 use the new global types. */
2626 preserve_values (struct objfile *objfile)
2628 htab_t copied_types;
2629 struct value_history_chunk *cur;
2630 struct internalvar *var;
2633 /* Create the hash table. We allocate on the objfile's obstack, since
2634 it is soon to be deleted. */
2635 copied_types = create_copied_types_hash (objfile);
2637 for (cur = value_history_chain; cur; cur = cur->next)
2638 for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
2640 preserve_one_value (cur->values[i], objfile, copied_types);
2642 for (var = internalvars; var; var = var->next)
2643 preserve_one_internalvar (var, objfile, copied_types);
2645 preserve_ext_lang_values (objfile, copied_types);
2647 htab_delete (copied_types);
2651 show_convenience (const char *ignore, int from_tty)
2653 struct gdbarch *gdbarch = get_current_arch ();
2654 struct internalvar *var;
2656 struct value_print_options opts;
2658 get_user_print_options (&opts);
2659 for (var = internalvars; var; var = var->next)
2666 printf_filtered (("$%s = "), var->name);
2672 val = value_of_internalvar (gdbarch, var);
2673 value_print (val, gdb_stdout, &opts);
2675 CATCH (ex, RETURN_MASK_ERROR)
2677 fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
2681 printf_filtered (("\n"));
2685 /* This text does not mention convenience functions on purpose.
2686 The user can't create them except via Python, and if Python support
2687 is installed this message will never be printed ($_streq will
2689 printf_unfiltered (_("No debugger convenience variables now defined.\n"
2690 "Convenience variables have "
2691 "names starting with \"$\";\n"
2692 "use \"set\" as in \"set "
2693 "$foo = 5\" to define them.\n"));
2701 value_from_xmethod (xmethod_worker_up &&worker)
2705 v = allocate_value (builtin_type (target_gdbarch ())->xmethod);
2706 v->lval = lval_xcallable;
2707 v->location.xm_worker = worker.release ();
2713 /* Return the type of the result of TYPE_CODE_XMETHOD value METHOD. */
2716 result_type_of_xmethod (struct value *method, int argc, struct value **argv)
2718 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2719 && method->lval == lval_xcallable && argc > 0);
2721 return method->location.xm_worker->get_result_type
2722 (argv[0], argv + 1, argc - 1);
2725 /* Call the xmethod corresponding to the TYPE_CODE_XMETHOD value METHOD. */
2728 call_xmethod (struct value *method, int argc, struct value **argv)
2730 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2731 && method->lval == lval_xcallable && argc > 0);
2733 return method->location.xm_worker->invoke (argv[0], argv + 1, argc - 1);
2736 /* Extract a value as a C number (either long or double).
2737 Knows how to convert fixed values to double, or
2738 floating values to long.
2739 Does not deallocate the value. */
2742 value_as_long (struct value *val)
2744 /* This coerces arrays and functions, which is necessary (e.g.
2745 in disassemble_command). It also dereferences references, which
2746 I suspect is the most logical thing to do. */
2747 val = coerce_array (val);
2748 return unpack_long (value_type (val), value_contents (val));
2751 /* Extract a value as a C pointer. Does not deallocate the value.
2752 Note that val's type may not actually be a pointer; value_as_long
2753 handles all the cases. */
2755 value_as_address (struct value *val)
2757 struct gdbarch *gdbarch = get_type_arch (value_type (val));
2759 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2760 whether we want this to be true eventually. */
2762 /* gdbarch_addr_bits_remove is wrong if we are being called for a
2763 non-address (e.g. argument to "signal", "info break", etc.), or
2764 for pointers to char, in which the low bits *are* significant. */
2765 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
2768 /* There are several targets (IA-64, PowerPC, and others) which
2769 don't represent pointers to functions as simply the address of
2770 the function's entry point. For example, on the IA-64, a
2771 function pointer points to a two-word descriptor, generated by
2772 the linker, which contains the function's entry point, and the
2773 value the IA-64 "global pointer" register should have --- to
2774 support position-independent code. The linker generates
2775 descriptors only for those functions whose addresses are taken.
2777 On such targets, it's difficult for GDB to convert an arbitrary
2778 function address into a function pointer; it has to either find
2779 an existing descriptor for that function, or call malloc and
2780 build its own. On some targets, it is impossible for GDB to
2781 build a descriptor at all: the descriptor must contain a jump
2782 instruction; data memory cannot be executed; and code memory
2785 Upon entry to this function, if VAL is a value of type `function'
2786 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2787 value_address (val) is the address of the function. This is what
2788 you'll get if you evaluate an expression like `main'. The call
2789 to COERCE_ARRAY below actually does all the usual unary
2790 conversions, which includes converting values of type `function'
2791 to `pointer to function'. This is the challenging conversion
2792 discussed above. Then, `unpack_long' will convert that pointer
2793 back into an address.
2795 So, suppose the user types `disassemble foo' on an architecture
2796 with a strange function pointer representation, on which GDB
2797 cannot build its own descriptors, and suppose further that `foo'
2798 has no linker-built descriptor. The address->pointer conversion
2799 will signal an error and prevent the command from running, even
2800 though the next step would have been to convert the pointer
2801 directly back into the same address.
2803 The following shortcut avoids this whole mess. If VAL is a
2804 function, just return its address directly. */
2805 if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
2806 || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
2807 return value_address (val);
2809 val = coerce_array (val);
2811 /* Some architectures (e.g. Harvard), map instruction and data
2812 addresses onto a single large unified address space. For
2813 instance: An architecture may consider a large integer in the
2814 range 0x10000000 .. 0x1000ffff to already represent a data
2815 addresses (hence not need a pointer to address conversion) while
2816 a small integer would still need to be converted integer to
2817 pointer to address. Just assume such architectures handle all
2818 integer conversions in a single function. */
2822 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2823 must admonish GDB hackers to make sure its behavior matches the
2824 compiler's, whenever possible.
2826 In general, I think GDB should evaluate expressions the same way
2827 the compiler does. When the user copies an expression out of
2828 their source code and hands it to a `print' command, they should
2829 get the same value the compiler would have computed. Any
2830 deviation from this rule can cause major confusion and annoyance,
2831 and needs to be justified carefully. In other words, GDB doesn't
2832 really have the freedom to do these conversions in clever and
2835 AndrewC pointed out that users aren't complaining about how GDB
2836 casts integers to pointers; they are complaining that they can't
2837 take an address from a disassembly listing and give it to `x/i'.
2838 This is certainly important.
2840 Adding an architecture method like integer_to_address() certainly
2841 makes it possible for GDB to "get it right" in all circumstances
2842 --- the target has complete control over how things get done, so
2843 people can Do The Right Thing for their target without breaking
2844 anyone else. The standard doesn't specify how integers get
2845 converted to pointers; usually, the ABI doesn't either, but
2846 ABI-specific code is a more reasonable place to handle it. */
2848 if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR
2849 && !TYPE_IS_REFERENCE (value_type (val))
2850 && gdbarch_integer_to_address_p (gdbarch))
2851 return gdbarch_integer_to_address (gdbarch, value_type (val),
2852 value_contents (val));
2854 return unpack_long (value_type (val), value_contents (val));
2858 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2859 as a long, or as a double, assuming the raw data is described
2860 by type TYPE. Knows how to convert different sizes of values
2861 and can convert between fixed and floating point. We don't assume
2862 any alignment for the raw data. Return value is in host byte order.
2864 If you want functions and arrays to be coerced to pointers, and
2865 references to be dereferenced, call value_as_long() instead.
2867 C++: It is assumed that the front-end has taken care of
2868 all matters concerning pointers to members. A pointer
2869 to member which reaches here is considered to be equivalent
2870 to an INT (or some size). After all, it is only an offset. */
2873 unpack_long (struct type *type, const gdb_byte *valaddr)
2875 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2876 enum type_code code = TYPE_CODE (type);
2877 int len = TYPE_LENGTH (type);
2878 int nosign = TYPE_UNSIGNED (type);
2882 case TYPE_CODE_TYPEDEF:
2883 return unpack_long (check_typedef (type), valaddr);
2884 case TYPE_CODE_ENUM:
2885 case TYPE_CODE_FLAGS:
2886 case TYPE_CODE_BOOL:
2888 case TYPE_CODE_CHAR:
2889 case TYPE_CODE_RANGE:
2890 case TYPE_CODE_MEMBERPTR:
2892 return extract_unsigned_integer (valaddr, len, byte_order);
2894 return extract_signed_integer (valaddr, len, byte_order);
2897 case TYPE_CODE_DECFLOAT:
2898 return target_float_to_longest (valaddr, type);
2902 case TYPE_CODE_RVALUE_REF:
2903 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2904 whether we want this to be true eventually. */
2905 return extract_typed_address (valaddr, type);
2908 error (_("Value can't be converted to integer."));
2910 return 0; /* Placate lint. */
2913 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2914 as a CORE_ADDR, assuming the raw data is described by type TYPE.
2915 We don't assume any alignment for the raw data. Return value is in
2918 If you want functions and arrays to be coerced to pointers, and
2919 references to be dereferenced, call value_as_address() instead.
2921 C++: It is assumed that the front-end has taken care of
2922 all matters concerning pointers to members. A pointer
2923 to member which reaches here is considered to be equivalent
2924 to an INT (or some size). After all, it is only an offset. */
2927 unpack_pointer (struct type *type, const gdb_byte *valaddr)
2929 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2930 whether we want this to be true eventually. */
2931 return unpack_long (type, valaddr);
2935 is_floating_value (struct value *val)
2937 struct type *type = check_typedef (value_type (val));
2939 if (is_floating_type (type))
2941 if (!target_float_is_valid (value_contents (val), type))
2942 error (_("Invalid floating value found in program."));
2950 /* Get the value of the FIELDNO'th field (which must be static) of
2954 value_static_field (struct type *type, int fieldno)
2956 struct value *retval;
2958 switch (TYPE_FIELD_LOC_KIND (type, fieldno))
2960 case FIELD_LOC_KIND_PHYSADDR:
2961 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
2962 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
2964 case FIELD_LOC_KIND_PHYSNAME:
2966 const char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
2967 /* TYPE_FIELD_NAME (type, fieldno); */
2968 struct block_symbol sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
2970 if (sym.symbol == NULL)
2972 /* With some compilers, e.g. HP aCC, static data members are
2973 reported as non-debuggable symbols. */
2974 struct bound_minimal_symbol msym
2975 = lookup_minimal_symbol (phys_name, NULL, NULL);
2976 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
2979 retval = allocate_optimized_out_value (field_type);
2981 retval = value_at_lazy (field_type, BMSYMBOL_VALUE_ADDRESS (msym));
2984 retval = value_of_variable (sym.symbol, sym.block);
2988 gdb_assert_not_reached ("unexpected field location kind");
2994 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
2995 You have to be careful here, since the size of the data area for the value
2996 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
2997 than the old enclosing type, you have to allocate more space for the
3001 set_value_enclosing_type (struct value *val, struct type *new_encl_type)
3003 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
3005 check_type_length_before_alloc (new_encl_type);
3007 = (gdb_byte *) xrealloc (val->contents, TYPE_LENGTH (new_encl_type));
3010 val->enclosing_type = new_encl_type;
3013 /* Given a value ARG1 (offset by OFFSET bytes)
3014 of a struct or union type ARG_TYPE,
3015 extract and return the value of one of its (non-static) fields.
3016 FIELDNO says which field. */
3019 value_primitive_field (struct value *arg1, LONGEST offset,
3020 int fieldno, struct type *arg_type)
3024 struct gdbarch *arch = get_value_arch (arg1);
3025 int unit_size = gdbarch_addressable_memory_unit_size (arch);
3027 arg_type = check_typedef (arg_type);
3028 type = TYPE_FIELD_TYPE (arg_type, fieldno);
3030 /* Call check_typedef on our type to make sure that, if TYPE
3031 is a TYPE_CODE_TYPEDEF, its length is set to the length
3032 of the target type instead of zero. However, we do not
3033 replace the typedef type by the target type, because we want
3034 to keep the typedef in order to be able to print the type
3035 description correctly. */
3036 check_typedef (type);
3038 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
3040 /* Handle packed fields.
3042 Create a new value for the bitfield, with bitpos and bitsize
3043 set. If possible, arrange offset and bitpos so that we can
3044 do a single aligned read of the size of the containing type.
3045 Otherwise, adjust offset to the byte containing the first
3046 bit. Assume that the address, offset, and embedded offset
3047 are sufficiently aligned. */
3049 LONGEST bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
3050 LONGEST container_bitsize = TYPE_LENGTH (type) * 8;
3052 v = allocate_value_lazy (type);
3053 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
3054 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
3055 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
3056 v->bitpos = bitpos % container_bitsize;
3058 v->bitpos = bitpos % 8;
3059 v->offset = (value_embedded_offset (arg1)
3061 + (bitpos - v->bitpos) / 8);
3062 set_value_parent (v, arg1);
3063 if (!value_lazy (arg1))
3064 value_fetch_lazy (v);
3066 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
3068 /* This field is actually a base subobject, so preserve the
3069 entire object's contents for later references to virtual
3073 /* Lazy register values with offsets are not supported. */
3074 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3075 value_fetch_lazy (arg1);
3077 /* We special case virtual inheritance here because this
3078 requires access to the contents, which we would rather avoid
3079 for references to ordinary fields of unavailable values. */
3080 if (BASETYPE_VIA_VIRTUAL (arg_type, fieldno))
3081 boffset = baseclass_offset (arg_type, fieldno,
3082 value_contents (arg1),
3083 value_embedded_offset (arg1),
3084 value_address (arg1),
3087 boffset = TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
3089 if (value_lazy (arg1))
3090 v = allocate_value_lazy (value_enclosing_type (arg1));
3093 v = allocate_value (value_enclosing_type (arg1));
3094 value_contents_copy_raw (v, 0, arg1, 0,
3095 TYPE_LENGTH (value_enclosing_type (arg1)));
3098 v->offset = value_offset (arg1);
3099 v->embedded_offset = offset + value_embedded_offset (arg1) + boffset;
3101 else if (NULL != TYPE_DATA_LOCATION (type))
3103 /* Field is a dynamic data member. */
3105 gdb_assert (0 == offset);
3106 /* We expect an already resolved data location. */
3107 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (type));
3108 /* For dynamic data types defer memory allocation
3109 until we actual access the value. */
3110 v = allocate_value_lazy (type);
3114 /* Plain old data member */
3115 offset += (TYPE_FIELD_BITPOS (arg_type, fieldno)
3116 / (HOST_CHAR_BIT * unit_size));
3118 /* Lazy register values with offsets are not supported. */
3119 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3120 value_fetch_lazy (arg1);
3122 if (value_lazy (arg1))
3123 v = allocate_value_lazy (type);
3126 v = allocate_value (type);
3127 value_contents_copy_raw (v, value_embedded_offset (v),
3128 arg1, value_embedded_offset (arg1) + offset,
3129 type_length_units (type));
3131 v->offset = (value_offset (arg1) + offset
3132 + value_embedded_offset (arg1));
3134 set_value_component_location (v, arg1);
3138 /* Given a value ARG1 of a struct or union type,
3139 extract and return the value of one of its (non-static) fields.
3140 FIELDNO says which field. */
3143 value_field (struct value *arg1, int fieldno)
3145 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
3148 /* Return a non-virtual function as a value.
3149 F is the list of member functions which contains the desired method.
3150 J is an index into F which provides the desired method.
3152 We only use the symbol for its address, so be happy with either a
3153 full symbol or a minimal symbol. */
3156 value_fn_field (struct value **arg1p, struct fn_field *f,
3157 int j, struct type *type,
3161 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
3162 const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
3164 struct bound_minimal_symbol msym;
3166 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0).symbol;
3169 memset (&msym, 0, sizeof (msym));
3173 gdb_assert (sym == NULL);
3174 msym = lookup_bound_minimal_symbol (physname);
3175 if (msym.minsym == NULL)
3179 v = allocate_value (ftype);
3180 VALUE_LVAL (v) = lval_memory;
3183 set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (sym)));
3187 /* The minimal symbol might point to a function descriptor;
3188 resolve it to the actual code address instead. */
3189 struct objfile *objfile = msym.objfile;
3190 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3192 set_value_address (v,
3193 gdbarch_convert_from_func_ptr_addr
3194 (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), ¤t_target));
3199 if (type != value_type (*arg1p))
3200 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
3201 value_addr (*arg1p)));
3203 /* Move the `this' pointer according to the offset.
3204 VALUE_OFFSET (*arg1p) += offset; */
3212 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at
3213 VALADDR, and store the result in *RESULT.
3214 The bitfield starts at BITPOS bits and contains BITSIZE bits; if
3215 BITSIZE is zero, then the length is taken from FIELD_TYPE.
3217 Extracting bits depends on endianness of the machine. Compute the
3218 number of least significant bits to discard. For big endian machines,
3219 we compute the total number of bits in the anonymous object, subtract
3220 off the bit count from the MSB of the object to the MSB of the
3221 bitfield, then the size of the bitfield, which leaves the LSB discard
3222 count. For little endian machines, the discard count is simply the
3223 number of bits from the LSB of the anonymous object to the LSB of the
3226 If the field is signed, we also do sign extension. */
3229 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
3230 LONGEST bitpos, LONGEST bitsize)
3232 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
3237 LONGEST read_offset;
3239 /* Read the minimum number of bytes required; there may not be
3240 enough bytes to read an entire ULONGEST. */
3241 field_type = check_typedef (field_type);
3243 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
3246 bytes_read = TYPE_LENGTH (field_type);
3247 bitsize = 8 * bytes_read;
3250 read_offset = bitpos / 8;
3252 val = extract_unsigned_integer (valaddr + read_offset,
3253 bytes_read, byte_order);
3255 /* Extract bits. See comment above. */
3257 if (gdbarch_bits_big_endian (get_type_arch (field_type)))
3258 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
3260 lsbcount = (bitpos % 8);
3263 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
3264 If the field is signed, and is negative, then sign extend. */
3266 if (bitsize < 8 * (int) sizeof (val))
3268 valmask = (((ULONGEST) 1) << bitsize) - 1;
3270 if (!TYPE_UNSIGNED (field_type))
3272 if (val & (valmask ^ (valmask >> 1)))
3282 /* Unpack a field FIELDNO of the specified TYPE, from the object at
3283 VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
3284 ORIGINAL_VALUE, which must not be NULL. See
3285 unpack_value_bits_as_long for more details. */
3288 unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
3289 LONGEST embedded_offset, int fieldno,
3290 const struct value *val, LONGEST *result)
3292 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3293 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3294 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3297 gdb_assert (val != NULL);
3299 bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3300 if (value_bits_any_optimized_out (val, bit_offset, bitsize)
3301 || !value_bits_available (val, bit_offset, bitsize))
3304 *result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3309 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous
3310 object at VALADDR. See unpack_bits_as_long for more details. */
3313 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
3315 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3316 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3317 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3319 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
3322 /* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
3323 VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
3324 the contents in DEST_VAL, zero or sign extending if the type of
3325 DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
3326 VAL. If the VAL's contents required to extract the bitfield from
3327 are unavailable/optimized out, DEST_VAL is correspondingly
3328 marked unavailable/optimized out. */
3331 unpack_value_bitfield (struct value *dest_val,
3332 LONGEST bitpos, LONGEST bitsize,
3333 const gdb_byte *valaddr, LONGEST embedded_offset,
3334 const struct value *val)
3336 enum bfd_endian byte_order;
3339 struct type *field_type = value_type (dest_val);
3341 byte_order = gdbarch_byte_order (get_type_arch (field_type));
3343 /* First, unpack and sign extend the bitfield as if it was wholly
3344 valid. Optimized out/unavailable bits are read as zero, but
3345 that's OK, as they'll end up marked below. If the VAL is
3346 wholly-invalid we may have skipped allocating its contents,
3347 though. See allocate_optimized_out_value. */
3348 if (valaddr != NULL)
3352 num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3354 store_signed_integer (value_contents_raw (dest_val),
3355 TYPE_LENGTH (field_type), byte_order, num);
3358 /* Now copy the optimized out / unavailability ranges to the right
3360 src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3361 if (byte_order == BFD_ENDIAN_BIG)
3362 dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
3365 value_ranges_copy_adjusted (dest_val, dst_bit_offset,
3366 val, src_bit_offset, bitsize);
3369 /* Return a new value with type TYPE, which is FIELDNO field of the
3370 object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
3371 of VAL. If the VAL's contents required to extract the bitfield
3372 from are unavailable/optimized out, the new value is
3373 correspondingly marked unavailable/optimized out. */
3376 value_field_bitfield (struct type *type, int fieldno,
3377 const gdb_byte *valaddr,
3378 LONGEST embedded_offset, const struct value *val)
3380 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3381 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3382 struct value *res_val = allocate_value (TYPE_FIELD_TYPE (type, fieldno));
3384 unpack_value_bitfield (res_val, bitpos, bitsize,
3385 valaddr, embedded_offset, val);
3390 /* Modify the value of a bitfield. ADDR points to a block of memory in
3391 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
3392 is the desired value of the field, in host byte order. BITPOS and BITSIZE
3393 indicate which bits (in target bit order) comprise the bitfield.
3394 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
3395 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
3398 modify_field (struct type *type, gdb_byte *addr,
3399 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
3401 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3403 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
3406 /* Normalize BITPOS. */
3410 /* If a negative fieldval fits in the field in question, chop
3411 off the sign extension bits. */
3412 if ((~fieldval & ~(mask >> 1)) == 0)
3415 /* Warn if value is too big to fit in the field in question. */
3416 if (0 != (fieldval & ~mask))
3418 /* FIXME: would like to include fieldval in the message, but
3419 we don't have a sprintf_longest. */
3420 warning (_("Value does not fit in %s bits."), plongest (bitsize));
3422 /* Truncate it, otherwise adjoining fields may be corrupted. */
3426 /* Ensure no bytes outside of the modified ones get accessed as it may cause
3427 false valgrind reports. */
3429 bytesize = (bitpos + bitsize + 7) / 8;
3430 oword = extract_unsigned_integer (addr, bytesize, byte_order);
3432 /* Shifting for bit field depends on endianness of the target machine. */
3433 if (gdbarch_bits_big_endian (get_type_arch (type)))
3434 bitpos = bytesize * 8 - bitpos - bitsize;
3436 oword &= ~(mask << bitpos);
3437 oword |= fieldval << bitpos;
3439 store_unsigned_integer (addr, bytesize, byte_order, oword);
3442 /* Pack NUM into BUF using a target format of TYPE. */
3445 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
3447 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3450 type = check_typedef (type);
3451 len = TYPE_LENGTH (type);
3453 switch (TYPE_CODE (type))
3456 case TYPE_CODE_CHAR:
3457 case TYPE_CODE_ENUM:
3458 case TYPE_CODE_FLAGS:
3459 case TYPE_CODE_BOOL:
3460 case TYPE_CODE_RANGE:
3461 case TYPE_CODE_MEMBERPTR:
3462 store_signed_integer (buf, len, byte_order, num);
3466 case TYPE_CODE_RVALUE_REF:
3468 store_typed_address (buf, type, (CORE_ADDR) num);
3472 case TYPE_CODE_DECFLOAT:
3473 target_float_from_longest (buf, type, num);
3477 error (_("Unexpected type (%d) encountered for integer constant."),
3483 /* Pack NUM into BUF using a target format of TYPE. */
3486 pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
3489 enum bfd_endian byte_order;
3491 type = check_typedef (type);
3492 len = TYPE_LENGTH (type);
3493 byte_order = gdbarch_byte_order (get_type_arch (type));
3495 switch (TYPE_CODE (type))
3498 case TYPE_CODE_CHAR:
3499 case TYPE_CODE_ENUM:
3500 case TYPE_CODE_FLAGS:
3501 case TYPE_CODE_BOOL:
3502 case TYPE_CODE_RANGE:
3503 case TYPE_CODE_MEMBERPTR:
3504 store_unsigned_integer (buf, len, byte_order, num);
3508 case TYPE_CODE_RVALUE_REF:
3510 store_typed_address (buf, type, (CORE_ADDR) num);
3514 case TYPE_CODE_DECFLOAT:
3515 target_float_from_ulongest (buf, type, num);
3519 error (_("Unexpected type (%d) encountered "
3520 "for unsigned integer constant."),
3526 /* Convert C numbers into newly allocated values. */
3529 value_from_longest (struct type *type, LONGEST num)
3531 struct value *val = allocate_value (type);
3533 pack_long (value_contents_raw (val), type, num);
3538 /* Convert C unsigned numbers into newly allocated values. */
3541 value_from_ulongest (struct type *type, ULONGEST num)
3543 struct value *val = allocate_value (type);
3545 pack_unsigned_long (value_contents_raw (val), type, num);
3551 /* Create a value representing a pointer of type TYPE to the address
3555 value_from_pointer (struct type *type, CORE_ADDR addr)
3557 struct value *val = allocate_value (type);
3559 store_typed_address (value_contents_raw (val),
3560 check_typedef (type), addr);
3565 /* Create a value of type TYPE whose contents come from VALADDR, if it
3566 is non-null, and whose memory address (in the inferior) is
3567 ADDRESS. The type of the created value may differ from the passed
3568 type TYPE. Make sure to retrieve values new type after this call.
3569 Note that TYPE is not passed through resolve_dynamic_type; this is
3570 a special API intended for use only by Ada. */
3573 value_from_contents_and_address_unresolved (struct type *type,
3574 const gdb_byte *valaddr,
3579 if (valaddr == NULL)
3580 v = allocate_value_lazy (type);
3582 v = value_from_contents (type, valaddr);
3583 VALUE_LVAL (v) = lval_memory;
3584 set_value_address (v, address);
3588 /* Create a value of type TYPE whose contents come from VALADDR, if it
3589 is non-null, and whose memory address (in the inferior) is
3590 ADDRESS. The type of the created value may differ from the passed
3591 type TYPE. Make sure to retrieve values new type after this call. */
3594 value_from_contents_and_address (struct type *type,
3595 const gdb_byte *valaddr,
3598 struct type *resolved_type = resolve_dynamic_type (type, valaddr, address);
3599 struct type *resolved_type_no_typedef = check_typedef (resolved_type);
3602 if (valaddr == NULL)
3603 v = allocate_value_lazy (resolved_type);
3605 v = value_from_contents (resolved_type, valaddr);
3606 if (TYPE_DATA_LOCATION (resolved_type_no_typedef) != NULL
3607 && TYPE_DATA_LOCATION_KIND (resolved_type_no_typedef) == PROP_CONST)
3608 address = TYPE_DATA_LOCATION_ADDR (resolved_type_no_typedef);
3609 VALUE_LVAL (v) = lval_memory;
3610 set_value_address (v, address);
3614 /* Create a value of type TYPE holding the contents CONTENTS.
3615 The new value is `not_lval'. */
3618 value_from_contents (struct type *type, const gdb_byte *contents)
3620 struct value *result;
3622 result = allocate_value (type);
3623 memcpy (value_contents_raw (result), contents, TYPE_LENGTH (type));
3627 /* Extract a value from the history file. Input will be of the form
3628 $digits or $$digits. See block comment above 'write_dollar_variable'
3632 value_from_history_ref (const char *h, const char **endp)
3644 /* Find length of numeral string. */
3645 for (; isdigit (h[len]); len++)
3648 /* Make sure numeral string is not part of an identifier. */
3649 if (h[len] == '_' || isalpha (h[len]))
3652 /* Now collect the index value. */
3657 /* For some bizarre reason, "$$" is equivalent to "$$1",
3658 rather than to "$$0" as it ought to be! */
3666 index = -strtol (&h[2], &local_end, 10);
3674 /* "$" is equivalent to "$0". */
3682 index = strtol (&h[1], &local_end, 10);
3687 return access_value_history (index);
3690 /* Get the component value (offset by OFFSET bytes) of a struct or
3691 union WHOLE. Component's type is TYPE. */
3694 value_from_component (struct value *whole, struct type *type, LONGEST offset)
3698 if (VALUE_LVAL (whole) == lval_memory && value_lazy (whole))
3699 v = allocate_value_lazy (type);
3702 v = allocate_value (type);
3703 value_contents_copy (v, value_embedded_offset (v),
3704 whole, value_embedded_offset (whole) + offset,
3705 type_length_units (type));
3707 v->offset = value_offset (whole) + offset + value_embedded_offset (whole);
3708 set_value_component_location (v, whole);
3714 coerce_ref_if_computed (const struct value *arg)
3716 const struct lval_funcs *funcs;
3718 if (!TYPE_IS_REFERENCE (check_typedef (value_type (arg))))
3721 if (value_lval_const (arg) != lval_computed)
3724 funcs = value_computed_funcs (arg);
3725 if (funcs->coerce_ref == NULL)
3728 return funcs->coerce_ref (arg);
3731 /* Look at value.h for description. */
3734 readjust_indirect_value_type (struct value *value, struct type *enc_type,
3735 const struct type *original_type,
3736 const struct value *original_value)
3738 /* Re-adjust type. */
3739 deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
3741 /* Add embedding info. */
3742 set_value_enclosing_type (value, enc_type);
3743 set_value_embedded_offset (value, value_pointed_to_offset (original_value));
3745 /* We may be pointing to an object of some derived type. */
3746 return value_full_object (value, NULL, 0, 0, 0);
3750 coerce_ref (struct value *arg)
3752 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
3753 struct value *retval;
3754 struct type *enc_type;
3756 retval = coerce_ref_if_computed (arg);
3760 if (!TYPE_IS_REFERENCE (value_type_arg_tmp))
3763 enc_type = check_typedef (value_enclosing_type (arg));
3764 enc_type = TYPE_TARGET_TYPE (enc_type);
3766 retval = value_at_lazy (enc_type,
3767 unpack_pointer (value_type (arg),
3768 value_contents (arg)));
3769 enc_type = value_type (retval);
3770 return readjust_indirect_value_type (retval, enc_type,
3771 value_type_arg_tmp, arg);
3775 coerce_array (struct value *arg)
3779 arg = coerce_ref (arg);
3780 type = check_typedef (value_type (arg));
3782 switch (TYPE_CODE (type))
3784 case TYPE_CODE_ARRAY:
3785 if (!TYPE_VECTOR (type) && current_language->c_style_arrays)
3786 arg = value_coerce_array (arg);
3788 case TYPE_CODE_FUNC:
3789 arg = value_coerce_function (arg);
3796 /* Return the return value convention that will be used for the
3799 enum return_value_convention
3800 struct_return_convention (struct gdbarch *gdbarch,
3801 struct value *function, struct type *value_type)
3803 enum type_code code = TYPE_CODE (value_type);
3805 if (code == TYPE_CODE_ERROR)
3806 error (_("Function return type unknown."));
3808 /* Probe the architecture for the return-value convention. */
3809 return gdbarch_return_value (gdbarch, function, value_type,
3813 /* Return true if the function returning the specified type is using
3814 the convention of returning structures in memory (passing in the
3815 address as a hidden first parameter). */
3818 using_struct_return (struct gdbarch *gdbarch,
3819 struct value *function, struct type *value_type)
3821 if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
3822 /* A void return value is never in memory. See also corresponding
3823 code in "print_return_value". */
3826 return (struct_return_convention (gdbarch, function, value_type)
3827 != RETURN_VALUE_REGISTER_CONVENTION);
3830 /* Set the initialized field in a value struct. */
3833 set_value_initialized (struct value *val, int status)
3835 val->initialized = status;
3838 /* Return the initialized field in a value struct. */
3841 value_initialized (const struct value *val)
3843 return val->initialized;
3846 /* Load the actual content of a lazy value. Fetch the data from the
3847 user's process and clear the lazy flag to indicate that the data in
3848 the buffer is valid.
3850 If the value is zero-length, we avoid calling read_memory, which
3851 would abort. We mark the value as fetched anyway -- all 0 bytes of
3855 value_fetch_lazy (struct value *val)
3857 gdb_assert (value_lazy (val));
3858 allocate_value_contents (val);
3859 /* A value is either lazy, or fully fetched. The
3860 availability/validity is only established as we try to fetch a
3862 gdb_assert (VEC_empty (range_s, val->optimized_out));
3863 gdb_assert (VEC_empty (range_s, val->unavailable));
3864 if (value_bitsize (val))
3866 /* To read a lazy bitfield, read the entire enclosing value. This
3867 prevents reading the same block of (possibly volatile) memory once
3868 per bitfield. It would be even better to read only the containing
3869 word, but we have no way to record that just specific bits of a
3870 value have been fetched. */
3871 struct type *type = check_typedef (value_type (val));
3872 struct value *parent = value_parent (val);
3874 if (value_lazy (parent))
3875 value_fetch_lazy (parent);
3877 unpack_value_bitfield (val,
3878 value_bitpos (val), value_bitsize (val),
3879 value_contents_for_printing (parent),
3880 value_offset (val), parent);
3882 else if (VALUE_LVAL (val) == lval_memory)
3884 CORE_ADDR addr = value_address (val);
3885 struct type *type = check_typedef (value_enclosing_type (val));
3887 if (TYPE_LENGTH (type))
3888 read_value_memory (val, 0, value_stack (val),
3889 addr, value_contents_all_raw (val),
3890 type_length_units (type));
3892 else if (VALUE_LVAL (val) == lval_register)
3894 struct frame_info *next_frame;
3896 struct type *type = check_typedef (value_type (val));
3897 struct value *new_val = val, *mark = value_mark ();
3899 /* Offsets are not supported here; lazy register values must
3900 refer to the entire register. */
3901 gdb_assert (value_offset (val) == 0);
3903 while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
3905 struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
3907 next_frame = frame_find_by_id (next_frame_id);
3908 regnum = VALUE_REGNUM (new_val);
3910 gdb_assert (next_frame != NULL);
3912 /* Convertible register routines are used for multi-register
3913 values and for interpretation in different types
3914 (e.g. float or int from a double register). Lazy
3915 register values should have the register's natural type,
3916 so they do not apply. */
3917 gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
3920 /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
3921 Since a "->next" operation was performed when setting
3922 this field, we do not need to perform a "next" operation
3923 again when unwinding the register. That's why
3924 frame_unwind_register_value() is called here instead of
3925 get_frame_register_value(). */
3926 new_val = frame_unwind_register_value (next_frame, regnum);
3928 /* If we get another lazy lval_register value, it means the
3929 register is found by reading it from NEXT_FRAME's next frame.
3930 frame_unwind_register_value should never return a value with
3931 the frame id pointing to NEXT_FRAME. If it does, it means we
3932 either have two consecutive frames with the same frame id
3933 in the frame chain, or some code is trying to unwind
3934 behind get_prev_frame's back (e.g., a frame unwind
3935 sniffer trying to unwind), bypassing its validations. In
3936 any case, it should always be an internal error to end up
3937 in this situation. */
3938 if (VALUE_LVAL (new_val) == lval_register
3939 && value_lazy (new_val)
3940 && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
3941 internal_error (__FILE__, __LINE__,
3942 _("infinite loop while fetching a register"));
3945 /* If it's still lazy (for instance, a saved register on the
3946 stack), fetch it. */
3947 if (value_lazy (new_val))
3948 value_fetch_lazy (new_val);
3950 /* Copy the contents and the unavailability/optimized-out
3951 meta-data from NEW_VAL to VAL. */
3952 set_value_lazy (val, 0);
3953 value_contents_copy (val, value_embedded_offset (val),
3954 new_val, value_embedded_offset (new_val),
3955 type_length_units (type));
3959 struct gdbarch *gdbarch;
3960 struct frame_info *frame;
3961 /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
3962 so that the frame level will be shown correctly. */
3963 frame = frame_find_by_id (VALUE_FRAME_ID (val));
3964 regnum = VALUE_REGNUM (val);
3965 gdbarch = get_frame_arch (frame);
3967 fprintf_unfiltered (gdb_stdlog,
3968 "{ value_fetch_lazy "
3969 "(frame=%d,regnum=%d(%s),...) ",
3970 frame_relative_level (frame), regnum,
3971 user_reg_map_regnum_to_name (gdbarch, regnum));
3973 fprintf_unfiltered (gdb_stdlog, "->");
3974 if (value_optimized_out (new_val))
3976 fprintf_unfiltered (gdb_stdlog, " ");
3977 val_print_optimized_out (new_val, gdb_stdlog);
3982 const gdb_byte *buf = value_contents (new_val);
3984 if (VALUE_LVAL (new_val) == lval_register)
3985 fprintf_unfiltered (gdb_stdlog, " register=%d",
3986 VALUE_REGNUM (new_val));
3987 else if (VALUE_LVAL (new_val) == lval_memory)
3988 fprintf_unfiltered (gdb_stdlog, " address=%s",
3990 value_address (new_val)));
3992 fprintf_unfiltered (gdb_stdlog, " computed");
3994 fprintf_unfiltered (gdb_stdlog, " bytes=");
3995 fprintf_unfiltered (gdb_stdlog, "[");
3996 for (i = 0; i < register_size (gdbarch, regnum); i++)
3997 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
3998 fprintf_unfiltered (gdb_stdlog, "]");
4001 fprintf_unfiltered (gdb_stdlog, " }\n");
4004 /* Dispose of the intermediate values. This prevents
4005 watchpoints from trying to watch the saved frame pointer. */
4006 value_free_to_mark (mark);
4008 else if (VALUE_LVAL (val) == lval_computed
4009 && value_computed_funcs (val)->read != NULL)
4010 value_computed_funcs (val)->read (val);
4012 internal_error (__FILE__, __LINE__, _("Unexpected lazy value type."));
4014 set_value_lazy (val, 0);
4017 /* Implementation of the convenience function $_isvoid. */
4019 static struct value *
4020 isvoid_internal_fn (struct gdbarch *gdbarch,
4021 const struct language_defn *language,
4022 void *cookie, int argc, struct value **argv)
4027 error (_("You must provide one argument for $_isvoid."));
4029 ret = TYPE_CODE (value_type (argv[0])) == TYPE_CODE_VOID;
4031 return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
4035 _initialize_values (void)
4037 add_cmd ("convenience", no_class, show_convenience, _("\
4038 Debugger convenience (\"$foo\") variables and functions.\n\
4039 Convenience variables are created when you assign them values;\n\
4040 thus, \"set $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
4042 A few convenience variables are given values automatically:\n\
4043 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
4044 \"$__\" holds the contents of the last address examined with \"x\"."
4047 Convenience functions are defined via the Python API."
4050 add_alias_cmd ("conv", "convenience", no_class, 1, &showlist);
4052 add_cmd ("values", no_set_class, show_values, _("\
4053 Elements of value history around item number IDX (or last ten)."),
4056 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
4057 Initialize a convenience variable if necessary.\n\
4058 init-if-undefined VARIABLE = EXPRESSION\n\
4059 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
4060 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
4061 VARIABLE is already initialized."));
4063 add_prefix_cmd ("function", no_class, function_command, _("\
4064 Placeholder command for showing help on convenience functions."),
4065 &functionlist, "function ", 0, &cmdlist);
4067 add_internal_function ("_isvoid", _("\
4068 Check whether an expression is void.\n\
4069 Usage: $_isvoid (expression)\n\
4070 Return 1 if the expression is void, zero otherwise."),
4071 isvoid_internal_fn, NULL);
4073 add_setshow_zuinteger_unlimited_cmd ("max-value-size",
4074 class_support, &max_value_size, _("\
4075 Set maximum sized value gdb will load from the inferior."), _("\
4076 Show maximum sized value gdb will load from the inferior."), _("\
4077 Use this to control the maximum size, in bytes, of a value that gdb\n\
4078 will load from the inferior. Setting this value to 'unlimited'\n\
4079 disables checking.\n\
4080 Setting this does not invalidate already allocated values, it only\n\
4081 prevents future values, larger than this size, from being allocated."),
4083 show_max_value_size,
4084 &setlist, &showlist);