1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986-2016 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"
37 #include "cli/cli-decode.h"
38 #include "extension.h"
40 #include "tracepoint.h"
42 #include "user-regs.h"
45 /* Prototypes for exported functions. */
47 void _initialize_values (void);
49 /* Definition of a user function. */
50 struct internal_function
52 /* The name of the function. It is a bit odd to have this in the
53 function itself -- the user might use a differently-named
54 convenience variable to hold the function. */
58 internal_function_fn handler;
60 /* User data for the handler. */
64 /* Defines an [OFFSET, OFFSET + LENGTH) range. */
68 /* Lowest offset in the range. */
71 /* Length of the range. */
75 typedef struct range range_s;
79 /* Returns true if the ranges defined by [offset1, offset1+len1) and
80 [offset2, offset2+len2) overlap. */
83 ranges_overlap (LONGEST offset1, LONGEST len1,
84 LONGEST offset2, LONGEST len2)
88 l = std::max (offset1, offset2);
89 h = std::min (offset1 + len1, offset2 + len2);
93 /* Returns true if the first argument is strictly less than the
94 second, useful for VEC_lower_bound. We keep ranges sorted by
95 offset and coalesce overlapping and contiguous ranges, so this just
96 compares the starting offset. */
99 range_lessthan (const range_s *r1, const range_s *r2)
101 return r1->offset < r2->offset;
104 /* Returns true if RANGES contains any range that overlaps [OFFSET,
108 ranges_contain (VEC(range_s) *ranges, LONGEST offset, LONGEST length)
113 what.offset = offset;
114 what.length = length;
116 /* We keep ranges sorted by offset and coalesce overlapping and
117 contiguous ranges, so to check if a range list contains a given
118 range, we can do a binary search for the position the given range
119 would be inserted if we only considered the starting OFFSET of
120 ranges. We call that position I. Since we also have LENGTH to
121 care for (this is a range afterall), we need to check if the
122 _previous_ range overlaps the I range. E.g.,
126 |---| |---| |------| ... |--|
131 In the case above, the binary search would return `I=1', meaning,
132 this OFFSET should be inserted at position 1, and the current
133 position 1 should be pushed further (and before 2). But, `0'
136 Then we need to check if the I range overlaps the I range itself.
141 |---| |---| |-------| ... |--|
147 i = VEC_lower_bound (range_s, ranges, &what, range_lessthan);
151 struct range *bef = VEC_index (range_s, ranges, i - 1);
153 if (ranges_overlap (bef->offset, bef->length, offset, length))
157 if (i < VEC_length (range_s, ranges))
159 struct range *r = VEC_index (range_s, ranges, i);
161 if (ranges_overlap (r->offset, r->length, offset, length))
168 static struct cmd_list_element *functionlist;
170 /* Note that the fields in this structure are arranged to save a bit
175 /* Type of value; either not an lval, or one of the various
176 different possible kinds of lval. */
179 /* Is it modifiable? Only relevant if lval != not_lval. */
180 unsigned int modifiable : 1;
182 /* If zero, contents of this value are in the contents field. If
183 nonzero, contents are in inferior. If the lval field is lval_memory,
184 the contents are in inferior memory at location.address plus offset.
185 The lval field may also be lval_register.
187 WARNING: This field is used by the code which handles watchpoints
188 (see breakpoint.c) to decide whether a particular value can be
189 watched by hardware watchpoints. If the lazy flag is set for
190 some member of a value chain, it is assumed that this member of
191 the chain doesn't need to be watched as part of watching the
192 value itself. This is how GDB avoids watching the entire struct
193 or array when the user wants to watch a single struct member or
194 array element. If you ever change the way lazy flag is set and
195 reset, be sure to consider this use as well! */
196 unsigned int lazy : 1;
198 /* If value is a variable, is it initialized or not. */
199 unsigned int initialized : 1;
201 /* If value is from the stack. If this is set, read_stack will be
202 used instead of read_memory to enable extra caching. */
203 unsigned int stack : 1;
205 /* If the value has been released. */
206 unsigned int released : 1;
208 /* Register number if the value is from a register. */
211 /* Location of value (if lval). */
214 /* If lval == lval_memory, this is the address in the inferior.
215 If lval == lval_register, this is the byte offset into the
216 registers structure. */
219 /* Pointer to internal variable. */
220 struct internalvar *internalvar;
222 /* Pointer to xmethod worker. */
223 struct xmethod_worker *xm_worker;
225 /* If lval == lval_computed, this is a set of function pointers
226 to use to access and describe the value, and a closure pointer
230 /* Functions to call. */
231 const struct lval_funcs *funcs;
233 /* Closure for those functions to use. */
238 /* Describes offset of a value within lval of a structure in target
239 addressable memory units. If lval == lval_memory, this is an offset to
240 the address. If lval == lval_register, this is a further offset from
241 location.address within the registers structure. Note also the member
242 embedded_offset below. */
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 /* Frame ID of "next" frame to which a register value is relative. A
266 register value is indicated when the lval enum (above) is set to
267 lval_register. So, if the register value is found relative to frame F,
268 then the frame id of F->next will be stored in next_frame_id. */
269 struct frame_id next_frame_id;
271 /* Type of the value. */
274 /* If a value represents a C++ object, then the `type' field gives
275 the object's compile-time type. If the object actually belongs
276 to some class derived from `type', perhaps with other base
277 classes and additional members, then `type' is just a subobject
278 of the real thing, and the full object is probably larger than
279 `type' would suggest.
281 If `type' is a dynamic class (i.e. one with a vtable), then GDB
282 can actually determine the object's run-time type by looking at
283 the run-time type information in the vtable. When this
284 information is available, we may elect to read in the entire
285 object, for several reasons:
287 - When printing the value, the user would probably rather see the
288 full object, not just the limited portion apparent from the
291 - If `type' has virtual base classes, then even printing `type'
292 alone may require reaching outside the `type' portion of the
293 object to wherever the virtual base class has been stored.
295 When we store the entire object, `enclosing_type' is the run-time
296 type -- the complete object -- and `embedded_offset' is the
297 offset of `type' within that larger type, in target addressable memory
298 units. The value_contents() macro takes `embedded_offset' into account,
299 so most GDB code continues to see the `type' portion of the value, just
300 as the inferior would.
302 If `type' is a pointer to an object, then `enclosing_type' is a
303 pointer to the object's run-time type, and `pointed_to_offset' is
304 the offset in target addressable memory units from the full object
305 to the pointed-to object -- that is, the value `embedded_offset' would
306 have if we followed the pointer and fetched the complete object.
307 (I don't really see the point. Why not just determine the
308 run-time type when you indirect, and avoid the special case? The
309 contents don't matter until you indirect anyway.)
311 If we're not doing anything fancy, `enclosing_type' is equal to
312 `type', and `embedded_offset' is zero, so everything works
314 struct type *enclosing_type;
315 LONGEST embedded_offset;
316 LONGEST pointed_to_offset;
318 /* Values are stored in a chain, so that they can be deleted easily
319 over calls to the inferior. Values assigned to internal
320 variables, put into the value history or exposed to Python are
321 taken off this list. */
324 /* Actual contents of the value. Target byte-order. NULL or not
325 valid if lazy is nonzero. */
328 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
329 rather than available, since the common and default case is for a
330 value to be available. This is filled in at value read time.
331 The unavailable ranges are tracked in bits. Note that a contents
332 bit that has been optimized out doesn't really exist in the
333 program, so it can't be marked unavailable either. */
334 VEC(range_s) *unavailable;
336 /* Likewise, but for optimized out contents (a chunk of the value of
337 a variable that does not actually exist in the program). If LVAL
338 is lval_register, this is a register ($pc, $sp, etc., never a
339 program variable) that has not been saved in the frame. Not
340 saved registers and optimized-out program variables values are
341 treated pretty much the same, except not-saved registers have a
342 different string representation and related error strings. */
343 VEC(range_s) *optimized_out;
349 get_value_arch (const struct value *value)
351 return get_type_arch (value_type (value));
355 value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
357 gdb_assert (!value->lazy);
359 return !ranges_contain (value->unavailable, offset, length);
363 value_bytes_available (const struct value *value,
364 LONGEST offset, LONGEST length)
366 return value_bits_available (value,
367 offset * TARGET_CHAR_BIT,
368 length * TARGET_CHAR_BIT);
372 value_bits_any_optimized_out (const struct value *value, int bit_offset, int bit_length)
374 gdb_assert (!value->lazy);
376 return ranges_contain (value->optimized_out, bit_offset, bit_length);
380 value_entirely_available (struct value *value)
382 /* We can only tell whether the whole value is available when we try
385 value_fetch_lazy (value);
387 if (VEC_empty (range_s, value->unavailable))
392 /* Returns true if VALUE is entirely covered by RANGES. If the value
393 is lazy, it'll be read now. Note that RANGE is a pointer to
394 pointer because reading the value might change *RANGE. */
397 value_entirely_covered_by_range_vector (struct value *value,
398 VEC(range_s) **ranges)
400 /* We can only tell whether the whole value is optimized out /
401 unavailable when we try to read it. */
403 value_fetch_lazy (value);
405 if (VEC_length (range_s, *ranges) == 1)
407 struct range *t = VEC_index (range_s, *ranges, 0);
410 && t->length == (TARGET_CHAR_BIT
411 * TYPE_LENGTH (value_enclosing_type (value))))
419 value_entirely_unavailable (struct value *value)
421 return value_entirely_covered_by_range_vector (value, &value->unavailable);
425 value_entirely_optimized_out (struct value *value)
427 return value_entirely_covered_by_range_vector (value, &value->optimized_out);
430 /* Insert into the vector pointed to by VECTORP the bit range starting of
431 OFFSET bits, and extending for the next LENGTH bits. */
434 insert_into_bit_range_vector (VEC(range_s) **vectorp,
435 LONGEST offset, LONGEST length)
440 /* Insert the range sorted. If there's overlap or the new range
441 would be contiguous with an existing range, merge. */
443 newr.offset = offset;
444 newr.length = length;
446 /* Do a binary search for the position the given range would be
447 inserted if we only considered the starting OFFSET of ranges.
448 Call that position I. Since we also have LENGTH to care for
449 (this is a range afterall), we need to check if the _previous_
450 range overlaps the I range. E.g., calling R the new range:
452 #1 - overlaps with previous
456 |---| |---| |------| ... |--|
461 In the case #1 above, the binary search would return `I=1',
462 meaning, this OFFSET should be inserted at position 1, and the
463 current position 1 should be pushed further (and become 2). But,
464 note that `0' overlaps with R, so we want to merge them.
466 A similar consideration needs to be taken if the new range would
467 be contiguous with the previous range:
469 #2 - contiguous with previous
473 |--| |---| |------| ... |--|
478 If there's no overlap with the previous range, as in:
480 #3 - not overlapping and not contiguous
484 |--| |---| |------| ... |--|
491 #4 - R is the range with lowest offset
495 |--| |---| |------| ... |--|
500 ... we just push the new range to I.
502 All the 4 cases above need to consider that the new range may
503 also overlap several of the ranges that follow, or that R may be
504 contiguous with the following range, and merge. E.g.,
506 #5 - overlapping following ranges
509 |------------------------|
510 |--| |---| |------| ... |--|
519 |--| |---| |------| ... |--|
526 i = VEC_lower_bound (range_s, *vectorp, &newr, range_lessthan);
529 struct range *bef = VEC_index (range_s, *vectorp, i - 1);
531 if (ranges_overlap (bef->offset, bef->length, offset, length))
534 ULONGEST l = std::min (bef->offset, offset);
535 ULONGEST h = std::max (bef->offset + bef->length, offset + length);
541 else if (offset == bef->offset + bef->length)
544 bef->length += length;
550 VEC_safe_insert (range_s, *vectorp, i, &newr);
556 VEC_safe_insert (range_s, *vectorp, i, &newr);
559 /* Check whether the ranges following the one we've just added or
560 touched can be folded in (#5 above). */
561 if (i + 1 < VEC_length (range_s, *vectorp))
568 /* Get the range we just touched. */
569 t = VEC_index (range_s, *vectorp, i);
573 for (; VEC_iterate (range_s, *vectorp, i, r); i++)
574 if (r->offset <= t->offset + t->length)
578 l = std::min (t->offset, r->offset);
579 h = std::max (t->offset + t->length, r->offset + r->length);
588 /* If we couldn't merge this one, we won't be able to
589 merge following ones either, since the ranges are
590 always sorted by OFFSET. */
595 VEC_block_remove (range_s, *vectorp, next, removed);
600 mark_value_bits_unavailable (struct value *value,
601 LONGEST offset, LONGEST length)
603 insert_into_bit_range_vector (&value->unavailable, offset, length);
607 mark_value_bytes_unavailable (struct value *value,
608 LONGEST offset, LONGEST length)
610 mark_value_bits_unavailable (value,
611 offset * TARGET_CHAR_BIT,
612 length * TARGET_CHAR_BIT);
615 /* Find the first range in RANGES that overlaps the range defined by
616 OFFSET and LENGTH, starting at element POS in the RANGES vector,
617 Returns the index into RANGES where such overlapping range was
618 found, or -1 if none was found. */
621 find_first_range_overlap (VEC(range_s) *ranges, int pos,
622 LONGEST offset, LONGEST length)
627 for (i = pos; VEC_iterate (range_s, ranges, i, r); i++)
628 if (ranges_overlap (r->offset, r->length, offset, length))
634 /* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
635 PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
638 It must always be the case that:
639 OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
641 It is assumed that memory can be accessed from:
642 PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
644 PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
645 / TARGET_CHAR_BIT) */
647 memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
648 const gdb_byte *ptr2, size_t offset2_bits,
651 gdb_assert (offset1_bits % TARGET_CHAR_BIT
652 == offset2_bits % TARGET_CHAR_BIT);
654 if (offset1_bits % TARGET_CHAR_BIT != 0)
657 gdb_byte mask, b1, b2;
659 /* The offset from the base pointers PTR1 and PTR2 is not a complete
660 number of bytes. A number of bits up to either the next exact
661 byte boundary, or LENGTH_BITS (which ever is sooner) will be
663 bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
664 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
665 mask = (1 << bits) - 1;
667 if (length_bits < bits)
669 mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
673 /* Now load the two bytes and mask off the bits we care about. */
674 b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
675 b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
680 /* Now update the length and offsets to take account of the bits
681 we've just compared. */
683 offset1_bits += bits;
684 offset2_bits += bits;
687 if (length_bits % TARGET_CHAR_BIT != 0)
691 gdb_byte mask, b1, b2;
693 /* The length is not an exact number of bytes. After the previous
694 IF.. block then the offsets are byte aligned, or the
695 length is zero (in which case this code is not reached). Compare
696 a number of bits at the end of the region, starting from an exact
698 bits = length_bits % TARGET_CHAR_BIT;
699 o1 = offset1_bits + length_bits - bits;
700 o2 = offset2_bits + length_bits - bits;
702 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
703 mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
705 gdb_assert (o1 % TARGET_CHAR_BIT == 0);
706 gdb_assert (o2 % TARGET_CHAR_BIT == 0);
708 b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
709 b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
719 /* We've now taken care of any stray "bits" at the start, or end of
720 the region to compare, the remainder can be covered with a simple
722 gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
723 gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
724 gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
726 return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
727 ptr2 + offset2_bits / TARGET_CHAR_BIT,
728 length_bits / TARGET_CHAR_BIT);
731 /* Length is zero, regions match. */
735 /* Helper struct for find_first_range_overlap_and_match and
736 value_contents_bits_eq. Keep track of which slot of a given ranges
737 vector have we last looked at. */
739 struct ranges_and_idx
742 VEC(range_s) *ranges;
744 /* The range we've last found in RANGES. Given ranges are sorted,
745 we can start the next lookup here. */
749 /* Helper function for value_contents_bits_eq. Compare LENGTH bits of
750 RP1's ranges starting at OFFSET1 bits with LENGTH bits of RP2's
751 ranges starting at OFFSET2 bits. Return true if the ranges match
752 and fill in *L and *H with the overlapping window relative to
753 (both) OFFSET1 or OFFSET2. */
756 find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
757 struct ranges_and_idx *rp2,
758 LONGEST offset1, LONGEST offset2,
759 LONGEST length, ULONGEST *l, ULONGEST *h)
761 rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
763 rp2->idx = find_first_range_overlap (rp2->ranges, rp2->idx,
766 if (rp1->idx == -1 && rp2->idx == -1)
772 else if (rp1->idx == -1 || rp2->idx == -1)
780 r1 = VEC_index (range_s, rp1->ranges, rp1->idx);
781 r2 = VEC_index (range_s, rp2->ranges, rp2->idx);
783 /* Get the unavailable windows intersected by the incoming
784 ranges. The first and last ranges that overlap the argument
785 range may be wider than said incoming arguments ranges. */
786 l1 = std::max (offset1, r1->offset);
787 h1 = std::min (offset1 + length, r1->offset + r1->length);
789 l2 = std::max (offset2, r2->offset);
790 h2 = std::min (offset2 + length, offset2 + r2->length);
792 /* Make them relative to the respective start offsets, so we can
793 compare them for equality. */
800 /* Different ranges, no match. */
801 if (l1 != l2 || h1 != h2)
810 /* Helper function for value_contents_eq. The only difference is that
811 this function is bit rather than byte based.
813 Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits
814 with LENGTH bits of VAL2's contents starting at OFFSET2 bits.
815 Return true if the available bits match. */
818 value_contents_bits_eq (const struct value *val1, int offset1,
819 const struct value *val2, int offset2,
822 /* Each array element corresponds to a ranges source (unavailable,
823 optimized out). '1' is for VAL1, '2' for VAL2. */
824 struct ranges_and_idx rp1[2], rp2[2];
826 /* See function description in value.h. */
827 gdb_assert (!val1->lazy && !val2->lazy);
829 /* We shouldn't be trying to compare past the end of the values. */
830 gdb_assert (offset1 + length
831 <= TYPE_LENGTH (val1->enclosing_type) * TARGET_CHAR_BIT);
832 gdb_assert (offset2 + length
833 <= TYPE_LENGTH (val2->enclosing_type) * TARGET_CHAR_BIT);
835 memset (&rp1, 0, sizeof (rp1));
836 memset (&rp2, 0, sizeof (rp2));
837 rp1[0].ranges = val1->unavailable;
838 rp2[0].ranges = val2->unavailable;
839 rp1[1].ranges = val1->optimized_out;
840 rp2[1].ranges = val2->optimized_out;
844 ULONGEST l = 0, h = 0; /* init for gcc -Wall */
847 for (i = 0; i < 2; i++)
849 ULONGEST l_tmp, h_tmp;
851 /* The contents only match equal if the invalid/unavailable
852 contents ranges match as well. */
853 if (!find_first_range_overlap_and_match (&rp1[i], &rp2[i],
854 offset1, offset2, length,
858 /* We're interested in the lowest/first range found. */
859 if (i == 0 || l_tmp < l)
866 /* Compare the available/valid contents. */
867 if (memcmp_with_bit_offsets (val1->contents, offset1,
868 val2->contents, offset2, l) != 0)
880 value_contents_eq (const struct value *val1, LONGEST offset1,
881 const struct value *val2, LONGEST offset2,
884 return value_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
885 val2, offset2 * TARGET_CHAR_BIT,
886 length * TARGET_CHAR_BIT);
889 /* Prototypes for local functions. */
891 static void show_values (char *, int);
893 static void show_convenience (char *, int);
896 /* The value-history records all the values printed
897 by print commands during this session. Each chunk
898 records 60 consecutive values. The first chunk on
899 the chain records the most recent values.
900 The total number of values is in value_history_count. */
902 #define VALUE_HISTORY_CHUNK 60
904 struct value_history_chunk
906 struct value_history_chunk *next;
907 struct value *values[VALUE_HISTORY_CHUNK];
910 /* Chain of chunks now in use. */
912 static struct value_history_chunk *value_history_chain;
914 static int value_history_count; /* Abs number of last entry stored. */
917 /* List of all value objects currently allocated
918 (except for those released by calls to release_value)
919 This is so they can be freed after each command. */
921 static struct value *all_values;
923 /* Allocate a lazy value for type TYPE. Its actual content is
924 "lazily" allocated too: the content field of the return value is
925 NULL; it will be allocated when it is fetched from the target. */
928 allocate_value_lazy (struct type *type)
932 /* Call check_typedef on our type to make sure that, if TYPE
933 is a TYPE_CODE_TYPEDEF, its length is set to the length
934 of the target type instead of zero. However, we do not
935 replace the typedef type by the target type, because we want
936 to keep the typedef in order to be able to set the VAL's type
937 description correctly. */
938 check_typedef (type);
940 val = XCNEW (struct value);
941 val->contents = NULL;
942 val->next = all_values;
945 val->enclosing_type = type;
946 VALUE_LVAL (val) = not_lval;
947 val->location.address = 0;
948 VALUE_NEXT_FRAME_ID (val) = null_frame_id;
952 VALUE_REGNUM (val) = -1;
954 val->embedded_offset = 0;
955 val->pointed_to_offset = 0;
957 val->initialized = 1; /* Default to initialized. */
959 /* Values start out on the all_values chain. */
960 val->reference_count = 1;
965 /* The maximum size, in bytes, that GDB will try to allocate for a value.
966 The initial value of 64k was not selected for any specific reason, it is
967 just a reasonable starting point. */
969 static int max_value_size = 65536; /* 64k bytes */
971 /* It is critical that the MAX_VALUE_SIZE is at least as big as the size of
972 LONGEST, otherwise GDB will not be able to parse integer values from the
973 CLI; for example if the MAX_VALUE_SIZE could be set to 1 then GDB would
974 be unable to parse "set max-value-size 2".
976 As we want a consistent GDB experience across hosts with different sizes
977 of LONGEST, this arbitrary minimum value was selected, so long as this
978 is bigger than LONGEST on all GDB supported hosts we're fine. */
980 #define MIN_VALUE_FOR_MAX_VALUE_SIZE 16
981 gdb_static_assert (sizeof (LONGEST) <= MIN_VALUE_FOR_MAX_VALUE_SIZE);
983 /* Implement the "set max-value-size" command. */
986 set_max_value_size (char *args, int from_tty,
987 struct cmd_list_element *c)
989 gdb_assert (max_value_size == -1 || max_value_size >= 0);
991 if (max_value_size > -1 && max_value_size < MIN_VALUE_FOR_MAX_VALUE_SIZE)
993 max_value_size = MIN_VALUE_FOR_MAX_VALUE_SIZE;
994 error (_("max-value-size set too low, increasing to %d bytes"),
999 /* Implement the "show max-value-size" command. */
1002 show_max_value_size (struct ui_file *file, int from_tty,
1003 struct cmd_list_element *c, const char *value)
1005 if (max_value_size == -1)
1006 fprintf_filtered (file, _("Maximum value size is unlimited.\n"));
1008 fprintf_filtered (file, _("Maximum value size is %d bytes.\n"),
1012 /* Called before we attempt to allocate or reallocate a buffer for the
1013 contents of a value. TYPE is the type of the value for which we are
1014 allocating the buffer. If the buffer is too large (based on the user
1015 controllable setting) then throw an error. If this function returns
1016 then we should attempt to allocate the buffer. */
1019 check_type_length_before_alloc (const struct type *type)
1021 unsigned int length = TYPE_LENGTH (type);
1023 if (max_value_size > -1 && length > max_value_size)
1025 if (TYPE_NAME (type) != NULL)
1026 error (_("value of type `%s' requires %u bytes, which is more "
1027 "than max-value-size"), TYPE_NAME (type), length);
1029 error (_("value requires %u bytes, which is more than "
1030 "max-value-size"), length);
1034 /* Allocate the contents of VAL if it has not been allocated yet. */
1037 allocate_value_contents (struct value *val)
1041 check_type_length_before_alloc (val->enclosing_type);
1043 = (gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type));
1047 /* Allocate a value and its contents for type TYPE. */
1050 allocate_value (struct type *type)
1052 struct value *val = allocate_value_lazy (type);
1054 allocate_value_contents (val);
1059 /* Allocate a value that has the correct length
1060 for COUNT repetitions of type TYPE. */
1063 allocate_repeat_value (struct type *type, int count)
1065 int low_bound = current_language->string_lower_bound; /* ??? */
1066 /* FIXME-type-allocation: need a way to free this type when we are
1068 struct type *array_type
1069 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
1071 return allocate_value (array_type);
1075 allocate_computed_value (struct type *type,
1076 const struct lval_funcs *funcs,
1079 struct value *v = allocate_value_lazy (type);
1081 VALUE_LVAL (v) = lval_computed;
1082 v->location.computed.funcs = funcs;
1083 v->location.computed.closure = closure;
1088 /* Allocate NOT_LVAL value for type TYPE being OPTIMIZED_OUT. */
1091 allocate_optimized_out_value (struct type *type)
1093 struct value *retval = allocate_value_lazy (type);
1095 mark_value_bytes_optimized_out (retval, 0, TYPE_LENGTH (type));
1096 set_value_lazy (retval, 0);
1100 /* Accessor methods. */
1103 value_next (const struct value *value)
1109 value_type (const struct value *value)
1114 deprecated_set_value_type (struct value *value, struct type *type)
1120 value_offset (const struct value *value)
1122 return value->offset;
1125 set_value_offset (struct value *value, LONGEST offset)
1127 value->offset = offset;
1131 value_bitpos (const struct value *value)
1133 return value->bitpos;
1136 set_value_bitpos (struct value *value, LONGEST bit)
1138 value->bitpos = bit;
1142 value_bitsize (const struct value *value)
1144 return value->bitsize;
1147 set_value_bitsize (struct value *value, LONGEST bit)
1149 value->bitsize = bit;
1153 value_parent (const struct value *value)
1155 return value->parent;
1161 set_value_parent (struct value *value, struct value *parent)
1163 struct value *old = value->parent;
1165 value->parent = parent;
1167 value_incref (parent);
1172 value_contents_raw (struct value *value)
1174 struct gdbarch *arch = get_value_arch (value);
1175 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1177 allocate_value_contents (value);
1178 return value->contents + value->embedded_offset * unit_size;
1182 value_contents_all_raw (struct value *value)
1184 allocate_value_contents (value);
1185 return value->contents;
1189 value_enclosing_type (const struct value *value)
1191 return value->enclosing_type;
1194 /* Look at value.h for description. */
1197 value_actual_type (struct value *value, int resolve_simple_types,
1198 int *real_type_found)
1200 struct value_print_options opts;
1201 struct type *result;
1203 get_user_print_options (&opts);
1205 if (real_type_found)
1206 *real_type_found = 0;
1207 result = value_type (value);
1208 if (opts.objectprint)
1210 /* If result's target type is TYPE_CODE_STRUCT, proceed to
1211 fetch its rtti type. */
1212 if ((TYPE_CODE (result) == TYPE_CODE_PTR
1213 || TYPE_CODE (result) == TYPE_CODE_REF)
1214 && TYPE_CODE (check_typedef (TYPE_TARGET_TYPE (result)))
1216 && !value_optimized_out (value))
1218 struct type *real_type;
1220 real_type = value_rtti_indirect_type (value, NULL, NULL, NULL);
1223 if (real_type_found)
1224 *real_type_found = 1;
1228 else if (resolve_simple_types)
1230 if (real_type_found)
1231 *real_type_found = 1;
1232 result = value_enclosing_type (value);
1240 error_value_optimized_out (void)
1242 error (_("value has been optimized out"));
1246 require_not_optimized_out (const struct value *value)
1248 if (!VEC_empty (range_s, value->optimized_out))
1250 if (value->lval == lval_register)
1251 error (_("register has not been saved in frame"));
1253 error_value_optimized_out ();
1258 require_available (const struct value *value)
1260 if (!VEC_empty (range_s, value->unavailable))
1261 throw_error (NOT_AVAILABLE_ERROR, _("value is not available"));
1265 value_contents_for_printing (struct value *value)
1268 value_fetch_lazy (value);
1269 return value->contents;
1273 value_contents_for_printing_const (const struct value *value)
1275 gdb_assert (!value->lazy);
1276 return value->contents;
1280 value_contents_all (struct value *value)
1282 const gdb_byte *result = value_contents_for_printing (value);
1283 require_not_optimized_out (value);
1284 require_available (value);
1288 /* Copy ranges in SRC_RANGE that overlap [SRC_BIT_OFFSET,
1289 SRC_BIT_OFFSET+BIT_LENGTH) ranges into *DST_RANGE, adjusted. */
1292 ranges_copy_adjusted (VEC (range_s) **dst_range, int dst_bit_offset,
1293 VEC (range_s) *src_range, int src_bit_offset,
1299 for (i = 0; VEC_iterate (range_s, src_range, i, r); i++)
1303 l = std::max (r->offset, (LONGEST) src_bit_offset);
1304 h = std::min (r->offset + r->length,
1305 (LONGEST) src_bit_offset + bit_length);
1308 insert_into_bit_range_vector (dst_range,
1309 dst_bit_offset + (l - src_bit_offset),
1314 /* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
1315 SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
1318 value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
1319 const struct value *src, int src_bit_offset,
1322 ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
1323 src->unavailable, src_bit_offset,
1325 ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
1326 src->optimized_out, src_bit_offset,
1330 /* Copy LENGTH target addressable memory units of SRC value's (all) contents
1331 (value_contents_all) starting at SRC_OFFSET, into DST value's (all)
1332 contents, starting at DST_OFFSET. If unavailable contents are
1333 being copied from SRC, the corresponding DST contents are marked
1334 unavailable accordingly. Neither DST nor SRC may be lazy
1337 It is assumed the contents of DST in the [DST_OFFSET,
1338 DST_OFFSET+LENGTH) range are wholly available. */
1341 value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
1342 struct value *src, LONGEST src_offset, LONGEST length)
1344 LONGEST src_bit_offset, dst_bit_offset, bit_length;
1345 struct gdbarch *arch = get_value_arch (src);
1346 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1348 /* A lazy DST would make that this copy operation useless, since as
1349 soon as DST's contents were un-lazied (by a later value_contents
1350 call, say), the contents would be overwritten. A lazy SRC would
1351 mean we'd be copying garbage. */
1352 gdb_assert (!dst->lazy && !src->lazy);
1354 /* The overwritten DST range gets unavailability ORed in, not
1355 replaced. Make sure to remember to implement replacing if it
1356 turns out actually necessary. */
1357 gdb_assert (value_bytes_available (dst, dst_offset, length));
1358 gdb_assert (!value_bits_any_optimized_out (dst,
1359 TARGET_CHAR_BIT * dst_offset,
1360 TARGET_CHAR_BIT * length));
1362 /* Copy the data. */
1363 memcpy (value_contents_all_raw (dst) + dst_offset * unit_size,
1364 value_contents_all_raw (src) + src_offset * unit_size,
1365 length * unit_size);
1367 /* Copy the meta-data, adjusted. */
1368 src_bit_offset = src_offset * unit_size * HOST_CHAR_BIT;
1369 dst_bit_offset = dst_offset * unit_size * HOST_CHAR_BIT;
1370 bit_length = length * unit_size * HOST_CHAR_BIT;
1372 value_ranges_copy_adjusted (dst, dst_bit_offset,
1373 src, src_bit_offset,
1377 /* Copy LENGTH bytes of SRC value's (all) contents
1378 (value_contents_all) starting at SRC_OFFSET byte, into DST value's
1379 (all) contents, starting at DST_OFFSET. If unavailable contents
1380 are being copied from SRC, the corresponding DST contents are
1381 marked unavailable accordingly. DST must not be lazy. If SRC is
1382 lazy, it will be fetched now.
1384 It is assumed the contents of DST in the [DST_OFFSET,
1385 DST_OFFSET+LENGTH) range are wholly available. */
1388 value_contents_copy (struct value *dst, LONGEST dst_offset,
1389 struct value *src, LONGEST src_offset, LONGEST length)
1392 value_fetch_lazy (src);
1394 value_contents_copy_raw (dst, dst_offset, src, src_offset, length);
1398 value_lazy (const struct value *value)
1404 set_value_lazy (struct value *value, int val)
1410 value_stack (const struct value *value)
1412 return value->stack;
1416 set_value_stack (struct value *value, int val)
1422 value_contents (struct value *value)
1424 const gdb_byte *result = value_contents_writeable (value);
1425 require_not_optimized_out (value);
1426 require_available (value);
1431 value_contents_writeable (struct value *value)
1434 value_fetch_lazy (value);
1435 return value_contents_raw (value);
1439 value_optimized_out (struct value *value)
1441 /* We can only know if a value is optimized out once we have tried to
1443 if (VEC_empty (range_s, value->optimized_out) && value->lazy)
1447 value_fetch_lazy (value);
1449 CATCH (ex, RETURN_MASK_ERROR)
1451 /* Fall back to checking value->optimized_out. */
1456 return !VEC_empty (range_s, value->optimized_out);
1459 /* Mark contents of VALUE as optimized out, starting at OFFSET bytes, and
1460 the following LENGTH bytes. */
1463 mark_value_bytes_optimized_out (struct value *value, int offset, int length)
1465 mark_value_bits_optimized_out (value,
1466 offset * TARGET_CHAR_BIT,
1467 length * TARGET_CHAR_BIT);
1473 mark_value_bits_optimized_out (struct value *value,
1474 LONGEST offset, LONGEST length)
1476 insert_into_bit_range_vector (&value->optimized_out, offset, length);
1480 value_bits_synthetic_pointer (const struct value *value,
1481 LONGEST offset, LONGEST length)
1483 if (value->lval != lval_computed
1484 || !value->location.computed.funcs->check_synthetic_pointer)
1486 return value->location.computed.funcs->check_synthetic_pointer (value,
1492 value_embedded_offset (const struct value *value)
1494 return value->embedded_offset;
1498 set_value_embedded_offset (struct value *value, LONGEST val)
1500 value->embedded_offset = val;
1504 value_pointed_to_offset (const struct value *value)
1506 return value->pointed_to_offset;
1510 set_value_pointed_to_offset (struct value *value, LONGEST val)
1512 value->pointed_to_offset = val;
1515 const struct lval_funcs *
1516 value_computed_funcs (const struct value *v)
1518 gdb_assert (value_lval_const (v) == lval_computed);
1520 return v->location.computed.funcs;
1524 value_computed_closure (const struct value *v)
1526 gdb_assert (v->lval == lval_computed);
1528 return v->location.computed.closure;
1532 deprecated_value_lval_hack (struct value *value)
1534 return &value->lval;
1538 value_lval_const (const struct value *value)
1544 value_address (const struct value *value)
1546 if (value->lval == lval_internalvar
1547 || value->lval == lval_internalvar_component
1548 || value->lval == lval_xcallable)
1550 if (value->parent != NULL)
1551 return value_address (value->parent) + value->offset;
1552 if (NULL != TYPE_DATA_LOCATION (value_type (value)))
1554 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (value_type (value)));
1555 return TYPE_DATA_LOCATION_ADDR (value_type (value));
1558 return value->location.address + value->offset;
1562 value_raw_address (const struct value *value)
1564 if (value->lval == lval_internalvar
1565 || value->lval == lval_internalvar_component
1566 || value->lval == lval_xcallable)
1568 return value->location.address;
1572 set_value_address (struct value *value, CORE_ADDR addr)
1574 gdb_assert (value->lval != lval_internalvar
1575 && value->lval != lval_internalvar_component
1576 && value->lval != lval_xcallable);
1577 value->location.address = addr;
1580 struct internalvar **
1581 deprecated_value_internalvar_hack (struct value *value)
1583 return &value->location.internalvar;
1587 deprecated_value_next_frame_id_hack (struct value *value)
1589 return &value->next_frame_id;
1593 deprecated_value_regnum_hack (struct value *value)
1595 return &value->regnum;
1599 deprecated_value_modifiable (const struct value *value)
1601 return value->modifiable;
1604 /* Return a mark in the value chain. All values allocated after the
1605 mark is obtained (except for those released) are subject to being freed
1606 if a subsequent value_free_to_mark is passed the mark. */
1613 /* Take a reference to VAL. VAL will not be deallocated until all
1614 references are released. */
1617 value_incref (struct value *val)
1619 val->reference_count++;
1622 /* Release a reference to VAL, which was acquired with value_incref.
1623 This function is also called to deallocate values from the value
1627 value_free (struct value *val)
1631 gdb_assert (val->reference_count > 0);
1632 val->reference_count--;
1633 if (val->reference_count > 0)
1636 /* If there's an associated parent value, drop our reference to
1638 if (val->parent != NULL)
1639 value_free (val->parent);
1641 if (VALUE_LVAL (val) == lval_computed)
1643 const struct lval_funcs *funcs = val->location.computed.funcs;
1645 if (funcs->free_closure)
1646 funcs->free_closure (val);
1648 else if (VALUE_LVAL (val) == lval_xcallable)
1649 free_xmethod_worker (val->location.xm_worker);
1651 xfree (val->contents);
1652 VEC_free (range_s, val->unavailable);
1657 /* Free all values allocated since MARK was obtained by value_mark
1658 (except for those released). */
1660 value_free_to_mark (const struct value *mark)
1665 for (val = all_values; val && val != mark; val = next)
1674 /* Free all the values that have been allocated (except for those released).
1675 Call after each command, successful or not.
1676 In practice this is called before each command, which is sufficient. */
1679 free_all_values (void)
1684 for (val = all_values; val; val = next)
1694 /* Frees all the elements in a chain of values. */
1697 free_value_chain (struct value *v)
1703 next = value_next (v);
1708 /* Remove VAL from the chain all_values
1709 so it will not be freed automatically. */
1712 release_value (struct value *val)
1716 if (all_values == val)
1718 all_values = val->next;
1724 for (v = all_values; v; v = v->next)
1728 v->next = val->next;
1736 /* If the value is not already released, release it.
1737 If the value is already released, increment its reference count.
1738 That is, this function ensures that the value is released from the
1739 value chain and that the caller owns a reference to it. */
1742 release_value_or_incref (struct value *val)
1747 release_value (val);
1750 /* Release all values up to mark */
1752 value_release_to_mark (const struct value *mark)
1757 for (val = next = all_values; next; next = next->next)
1759 if (next->next == mark)
1761 all_values = next->next;
1771 /* Return a copy of the value ARG.
1772 It contains the same contents, for same memory address,
1773 but it's a different block of storage. */
1776 value_copy (struct value *arg)
1778 struct type *encl_type = value_enclosing_type (arg);
1781 if (value_lazy (arg))
1782 val = allocate_value_lazy (encl_type);
1784 val = allocate_value (encl_type);
1785 val->type = arg->type;
1786 VALUE_LVAL (val) = VALUE_LVAL (arg);
1787 val->location = arg->location;
1788 val->offset = arg->offset;
1789 val->bitpos = arg->bitpos;
1790 val->bitsize = arg->bitsize;
1791 VALUE_NEXT_FRAME_ID (val) = VALUE_NEXT_FRAME_ID (arg);
1792 VALUE_REGNUM (val) = VALUE_REGNUM (arg);
1793 val->lazy = arg->lazy;
1794 val->embedded_offset = value_embedded_offset (arg);
1795 val->pointed_to_offset = arg->pointed_to_offset;
1796 val->modifiable = arg->modifiable;
1797 if (!value_lazy (val))
1799 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
1800 TYPE_LENGTH (value_enclosing_type (arg)));
1803 val->unavailable = VEC_copy (range_s, arg->unavailable);
1804 val->optimized_out = VEC_copy (range_s, arg->optimized_out);
1805 set_value_parent (val, arg->parent);
1806 if (VALUE_LVAL (val) == lval_computed)
1808 const struct lval_funcs *funcs = val->location.computed.funcs;
1810 if (funcs->copy_closure)
1811 val->location.computed.closure = funcs->copy_closure (val);
1816 /* Return a "const" and/or "volatile" qualified version of the value V.
1817 If CNST is true, then the returned value will be qualified with
1819 if VOLTL is true, then the returned value will be qualified with
1823 make_cv_value (int cnst, int voltl, struct value *v)
1825 struct type *val_type = value_type (v);
1826 struct type *enclosing_type = value_enclosing_type (v);
1827 struct value *cv_val = value_copy (v);
1829 deprecated_set_value_type (cv_val,
1830 make_cv_type (cnst, voltl, val_type, NULL));
1831 set_value_enclosing_type (cv_val,
1832 make_cv_type (cnst, voltl, enclosing_type, NULL));
1837 /* Return a version of ARG that is non-lvalue. */
1840 value_non_lval (struct value *arg)
1842 if (VALUE_LVAL (arg) != not_lval)
1844 struct type *enc_type = value_enclosing_type (arg);
1845 struct value *val = allocate_value (enc_type);
1847 memcpy (value_contents_all_raw (val), value_contents_all (arg),
1848 TYPE_LENGTH (enc_type));
1849 val->type = arg->type;
1850 set_value_embedded_offset (val, value_embedded_offset (arg));
1851 set_value_pointed_to_offset (val, value_pointed_to_offset (arg));
1857 /* Write contents of V at ADDR and set its lval type to be LVAL_MEMORY. */
1860 value_force_lval (struct value *v, CORE_ADDR addr)
1862 gdb_assert (VALUE_LVAL (v) == not_lval);
1864 write_memory (addr, value_contents_raw (v), TYPE_LENGTH (value_type (v)));
1865 v->lval = lval_memory;
1866 v->location.address = addr;
1870 set_value_component_location (struct value *component,
1871 const struct value *whole)
1875 gdb_assert (whole->lval != lval_xcallable);
1877 if (whole->lval == lval_internalvar)
1878 VALUE_LVAL (component) = lval_internalvar_component;
1880 VALUE_LVAL (component) = whole->lval;
1882 component->location = whole->location;
1883 if (whole->lval == lval_computed)
1885 const struct lval_funcs *funcs = whole->location.computed.funcs;
1887 if (funcs->copy_closure)
1888 component->location.computed.closure = funcs->copy_closure (whole);
1891 /* If type has a dynamic resolved location property
1892 update it's value address. */
1893 type = value_type (whole);
1894 if (NULL != TYPE_DATA_LOCATION (type)
1895 && TYPE_DATA_LOCATION_KIND (type) == PROP_CONST)
1896 set_value_address (component, TYPE_DATA_LOCATION_ADDR (type));
1899 /* Access to the value history. */
1901 /* Record a new value in the value history.
1902 Returns the absolute history index of the entry. */
1905 record_latest_value (struct value *val)
1909 /* We don't want this value to have anything to do with the inferior anymore.
1910 In particular, "set $1 = 50" should not affect the variable from which
1911 the value was taken, and fast watchpoints should be able to assume that
1912 a value on the value history never changes. */
1913 if (value_lazy (val))
1914 value_fetch_lazy (val);
1915 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1916 from. This is a bit dubious, because then *&$1 does not just return $1
1917 but the current contents of that location. c'est la vie... */
1918 val->modifiable = 0;
1920 /* The value may have already been released, in which case we're adding a
1921 new reference for its entry in the history. That is why we call
1922 release_value_or_incref here instead of release_value. */
1923 release_value_or_incref (val);
1925 /* Here we treat value_history_count as origin-zero
1926 and applying to the value being stored now. */
1928 i = value_history_count % VALUE_HISTORY_CHUNK;
1931 struct value_history_chunk *newobj = XCNEW (struct value_history_chunk);
1933 newobj->next = value_history_chain;
1934 value_history_chain = newobj;
1937 value_history_chain->values[i] = val;
1939 /* Now we regard value_history_count as origin-one
1940 and applying to the value just stored. */
1942 return ++value_history_count;
1945 /* Return a copy of the value in the history with sequence number NUM. */
1948 access_value_history (int num)
1950 struct value_history_chunk *chunk;
1955 absnum += value_history_count;
1960 error (_("The history is empty."));
1962 error (_("There is only one value in the history."));
1964 error (_("History does not go back to $$%d."), -num);
1966 if (absnum > value_history_count)
1967 error (_("History has not yet reached $%d."), absnum);
1971 /* Now absnum is always absolute and origin zero. */
1973 chunk = value_history_chain;
1974 for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK
1975 - absnum / VALUE_HISTORY_CHUNK;
1977 chunk = chunk->next;
1979 return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
1983 show_values (char *num_exp, int from_tty)
1991 /* "show values +" should print from the stored position.
1992 "show values <exp>" should print around value number <exp>. */
1993 if (num_exp[0] != '+' || num_exp[1] != '\0')
1994 num = parse_and_eval_long (num_exp) - 5;
1998 /* "show values" means print the last 10 values. */
1999 num = value_history_count - 9;
2005 for (i = num; i < num + 10 && i <= value_history_count; i++)
2007 struct value_print_options opts;
2009 val = access_value_history (i);
2010 printf_filtered (("$%d = "), i);
2011 get_user_print_options (&opts);
2012 value_print (val, gdb_stdout, &opts);
2013 printf_filtered (("\n"));
2016 /* The next "show values +" should start after what we just printed. */
2019 /* Hitting just return after this command should do the same thing as
2020 "show values +". If num_exp is null, this is unnecessary, since
2021 "show values +" is not useful after "show values". */
2022 if (from_tty && num_exp)
2029 enum internalvar_kind
2031 /* The internal variable is empty. */
2034 /* The value of the internal variable is provided directly as
2035 a GDB value object. */
2038 /* A fresh value is computed via a call-back routine on every
2039 access to the internal variable. */
2040 INTERNALVAR_MAKE_VALUE,
2042 /* The internal variable holds a GDB internal convenience function. */
2043 INTERNALVAR_FUNCTION,
2045 /* The variable holds an integer value. */
2046 INTERNALVAR_INTEGER,
2048 /* The variable holds a GDB-provided string. */
2052 union internalvar_data
2054 /* A value object used with INTERNALVAR_VALUE. */
2055 struct value *value;
2057 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
2060 /* The functions to call. */
2061 const struct internalvar_funcs *functions;
2063 /* The function's user-data. */
2067 /* The internal function used with INTERNALVAR_FUNCTION. */
2070 struct internal_function *function;
2071 /* True if this is the canonical name for the function. */
2075 /* An integer value used with INTERNALVAR_INTEGER. */
2078 /* If type is non-NULL, it will be used as the type to generate
2079 a value for this internal variable. If type is NULL, a default
2080 integer type for the architecture is used. */
2085 /* A string value used with INTERNALVAR_STRING. */
2089 /* Internal variables. These are variables within the debugger
2090 that hold values assigned by debugger commands.
2091 The user refers to them with a '$' prefix
2092 that does not appear in the variable names stored internally. */
2096 struct internalvar *next;
2099 /* We support various different kinds of content of an internal variable.
2100 enum internalvar_kind specifies the kind, and union internalvar_data
2101 provides the data associated with this particular kind. */
2103 enum internalvar_kind kind;
2105 union internalvar_data u;
2108 static struct internalvar *internalvars;
2110 /* If the variable does not already exist create it and give it the
2111 value given. If no value is given then the default is zero. */
2113 init_if_undefined_command (char* args, int from_tty)
2115 struct internalvar* intvar;
2117 /* Parse the expression - this is taken from set_command(). */
2118 expression_up expr = parse_expression (args);
2120 /* Validate the expression.
2121 Was the expression an assignment?
2122 Or even an expression at all? */
2123 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
2124 error (_("Init-if-undefined requires an assignment expression."));
2126 /* Extract the variable from the parsed expression.
2127 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
2128 if (expr->elts[1].opcode != OP_INTERNALVAR)
2129 error (_("The first parameter to init-if-undefined "
2130 "should be a GDB variable."));
2131 intvar = expr->elts[2].internalvar;
2133 /* Only evaluate the expression if the lvalue is void.
2134 This may still fail if the expresssion is invalid. */
2135 if (intvar->kind == INTERNALVAR_VOID)
2136 evaluate_expression (expr.get ());
2140 /* Look up an internal variable with name NAME. NAME should not
2141 normally include a dollar sign.
2143 If the specified internal variable does not exist,
2144 the return value is NULL. */
2146 struct internalvar *
2147 lookup_only_internalvar (const char *name)
2149 struct internalvar *var;
2151 for (var = internalvars; var; var = var->next)
2152 if (strcmp (var->name, name) == 0)
2158 /* Complete NAME by comparing it to the names of internal variables.
2159 Returns a vector of newly allocated strings, or NULL if no matches
2163 complete_internalvar (const char *name)
2165 VEC (char_ptr) *result = NULL;
2166 struct internalvar *var;
2169 len = strlen (name);
2171 for (var = internalvars; var; var = var->next)
2172 if (strncmp (var->name, name, len) == 0)
2174 char *r = xstrdup (var->name);
2176 VEC_safe_push (char_ptr, result, r);
2182 /* Create an internal variable with name NAME and with a void value.
2183 NAME should not normally include a dollar sign. */
2185 struct internalvar *
2186 create_internalvar (const char *name)
2188 struct internalvar *var = XNEW (struct internalvar);
2190 var->name = concat (name, (char *)NULL);
2191 var->kind = INTERNALVAR_VOID;
2192 var->next = internalvars;
2197 /* Create an internal variable with name NAME and register FUN as the
2198 function that value_of_internalvar uses to create a value whenever
2199 this variable is referenced. NAME should not normally include a
2200 dollar sign. DATA is passed uninterpreted to FUN when it is
2201 called. CLEANUP, if not NULL, is called when the internal variable
2202 is destroyed. It is passed DATA as its only argument. */
2204 struct internalvar *
2205 create_internalvar_type_lazy (const char *name,
2206 const struct internalvar_funcs *funcs,
2209 struct internalvar *var = create_internalvar (name);
2211 var->kind = INTERNALVAR_MAKE_VALUE;
2212 var->u.make_value.functions = funcs;
2213 var->u.make_value.data = data;
2217 /* See documentation in value.h. */
2220 compile_internalvar_to_ax (struct internalvar *var,
2221 struct agent_expr *expr,
2222 struct axs_value *value)
2224 if (var->kind != INTERNALVAR_MAKE_VALUE
2225 || var->u.make_value.functions->compile_to_ax == NULL)
2228 var->u.make_value.functions->compile_to_ax (var, expr, value,
2229 var->u.make_value.data);
2233 /* Look up an internal variable with name NAME. NAME should not
2234 normally include a dollar sign.
2236 If the specified internal variable does not exist,
2237 one is created, with a void value. */
2239 struct internalvar *
2240 lookup_internalvar (const char *name)
2242 struct internalvar *var;
2244 var = lookup_only_internalvar (name);
2248 return create_internalvar (name);
2251 /* Return current value of internal variable VAR. For variables that
2252 are not inherently typed, use a value type appropriate for GDBARCH. */
2255 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
2258 struct trace_state_variable *tsv;
2260 /* If there is a trace state variable of the same name, assume that
2261 is what we really want to see. */
2262 tsv = find_trace_state_variable (var->name);
2265 tsv->value_known = target_get_trace_state_variable_value (tsv->number,
2267 if (tsv->value_known)
2268 val = value_from_longest (builtin_type (gdbarch)->builtin_int64,
2271 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2277 case INTERNALVAR_VOID:
2278 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2281 case INTERNALVAR_FUNCTION:
2282 val = allocate_value (builtin_type (gdbarch)->internal_fn);
2285 case INTERNALVAR_INTEGER:
2286 if (!var->u.integer.type)
2287 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
2288 var->u.integer.val);
2290 val = value_from_longest (var->u.integer.type, var->u.integer.val);
2293 case INTERNALVAR_STRING:
2294 val = value_cstring (var->u.string, strlen (var->u.string),
2295 builtin_type (gdbarch)->builtin_char);
2298 case INTERNALVAR_VALUE:
2299 val = value_copy (var->u.value);
2300 if (value_lazy (val))
2301 value_fetch_lazy (val);
2304 case INTERNALVAR_MAKE_VALUE:
2305 val = (*var->u.make_value.functions->make_value) (gdbarch, var,
2306 var->u.make_value.data);
2310 internal_error (__FILE__, __LINE__, _("bad kind"));
2313 /* Change the VALUE_LVAL to lval_internalvar so that future operations
2314 on this value go back to affect the original internal variable.
2316 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
2317 no underlying modifyable state in the internal variable.
2319 Likewise, if the variable's value is a computed lvalue, we want
2320 references to it to produce another computed lvalue, where
2321 references and assignments actually operate through the
2322 computed value's functions.
2324 This means that internal variables with computed values
2325 behave a little differently from other internal variables:
2326 assignments to them don't just replace the previous value
2327 altogether. At the moment, this seems like the behavior we
2330 if (var->kind != INTERNALVAR_MAKE_VALUE
2331 && val->lval != lval_computed)
2333 VALUE_LVAL (val) = lval_internalvar;
2334 VALUE_INTERNALVAR (val) = var;
2341 get_internalvar_integer (struct internalvar *var, LONGEST *result)
2343 if (var->kind == INTERNALVAR_INTEGER)
2345 *result = var->u.integer.val;
2349 if (var->kind == INTERNALVAR_VALUE)
2351 struct type *type = check_typedef (value_type (var->u.value));
2353 if (TYPE_CODE (type) == TYPE_CODE_INT)
2355 *result = value_as_long (var->u.value);
2364 get_internalvar_function (struct internalvar *var,
2365 struct internal_function **result)
2369 case INTERNALVAR_FUNCTION:
2370 *result = var->u.fn.function;
2379 set_internalvar_component (struct internalvar *var,
2380 LONGEST offset, LONGEST bitpos,
2381 LONGEST bitsize, struct value *newval)
2384 struct gdbarch *arch;
2389 case INTERNALVAR_VALUE:
2390 addr = value_contents_writeable (var->u.value);
2391 arch = get_value_arch (var->u.value);
2392 unit_size = gdbarch_addressable_memory_unit_size (arch);
2395 modify_field (value_type (var->u.value), addr + offset,
2396 value_as_long (newval), bitpos, bitsize);
2398 memcpy (addr + offset * unit_size, value_contents (newval),
2399 TYPE_LENGTH (value_type (newval)));
2403 /* We can never get a component of any other kind. */
2404 internal_error (__FILE__, __LINE__, _("set_internalvar_component"));
2409 set_internalvar (struct internalvar *var, struct value *val)
2411 enum internalvar_kind new_kind;
2412 union internalvar_data new_data = { 0 };
2414 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
2415 error (_("Cannot overwrite convenience function %s"), var->name);
2417 /* Prepare new contents. */
2418 switch (TYPE_CODE (check_typedef (value_type (val))))
2420 case TYPE_CODE_VOID:
2421 new_kind = INTERNALVAR_VOID;
2424 case TYPE_CODE_INTERNAL_FUNCTION:
2425 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2426 new_kind = INTERNALVAR_FUNCTION;
2427 get_internalvar_function (VALUE_INTERNALVAR (val),
2428 &new_data.fn.function);
2429 /* Copies created here are never canonical. */
2433 new_kind = INTERNALVAR_VALUE;
2434 new_data.value = value_copy (val);
2435 new_data.value->modifiable = 1;
2437 /* Force the value to be fetched from the target now, to avoid problems
2438 later when this internalvar is referenced and the target is gone or
2440 if (value_lazy (new_data.value))
2441 value_fetch_lazy (new_data.value);
2443 /* Release the value from the value chain to prevent it from being
2444 deleted by free_all_values. From here on this function should not
2445 call error () until new_data is installed into the var->u to avoid
2447 release_value (new_data.value);
2449 /* Internal variables which are created from values with a dynamic
2450 location don't need the location property of the origin anymore.
2451 The resolved dynamic location is used prior then any other address
2452 when accessing the value.
2453 If we keep it, we would still refer to the origin value.
2454 Remove the location property in case it exist. */
2455 remove_dyn_prop (DYN_PROP_DATA_LOCATION, value_type (new_data.value));
2460 /* Clean up old contents. */
2461 clear_internalvar (var);
2464 var->kind = new_kind;
2466 /* End code which must not call error(). */
2470 set_internalvar_integer (struct internalvar *var, LONGEST l)
2472 /* Clean up old contents. */
2473 clear_internalvar (var);
2475 var->kind = INTERNALVAR_INTEGER;
2476 var->u.integer.type = NULL;
2477 var->u.integer.val = l;
2481 set_internalvar_string (struct internalvar *var, const char *string)
2483 /* Clean up old contents. */
2484 clear_internalvar (var);
2486 var->kind = INTERNALVAR_STRING;
2487 var->u.string = xstrdup (string);
2491 set_internalvar_function (struct internalvar *var, struct internal_function *f)
2493 /* Clean up old contents. */
2494 clear_internalvar (var);
2496 var->kind = INTERNALVAR_FUNCTION;
2497 var->u.fn.function = f;
2498 var->u.fn.canonical = 1;
2499 /* Variables installed here are always the canonical version. */
2503 clear_internalvar (struct internalvar *var)
2505 /* Clean up old contents. */
2508 case INTERNALVAR_VALUE:
2509 value_free (var->u.value);
2512 case INTERNALVAR_STRING:
2513 xfree (var->u.string);
2516 case INTERNALVAR_MAKE_VALUE:
2517 if (var->u.make_value.functions->destroy != NULL)
2518 var->u.make_value.functions->destroy (var->u.make_value.data);
2525 /* Reset to void kind. */
2526 var->kind = INTERNALVAR_VOID;
2530 internalvar_name (const struct internalvar *var)
2535 static struct internal_function *
2536 create_internal_function (const char *name,
2537 internal_function_fn handler, void *cookie)
2539 struct internal_function *ifn = XNEW (struct internal_function);
2541 ifn->name = xstrdup (name);
2542 ifn->handler = handler;
2543 ifn->cookie = cookie;
2548 value_internal_function_name (struct value *val)
2550 struct internal_function *ifn;
2553 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2554 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
2555 gdb_assert (result);
2561 call_internal_function (struct gdbarch *gdbarch,
2562 const struct language_defn *language,
2563 struct value *func, int argc, struct value **argv)
2565 struct internal_function *ifn;
2568 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
2569 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
2570 gdb_assert (result);
2572 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
2575 /* The 'function' command. This does nothing -- it is just a
2576 placeholder to let "help function NAME" work. This is also used as
2577 the implementation of the sub-command that is created when
2578 registering an internal function. */
2580 function_command (char *command, int from_tty)
2585 /* Clean up if an internal function's command is destroyed. */
2587 function_destroyer (struct cmd_list_element *self, void *ignore)
2589 xfree ((char *) self->name);
2590 xfree ((char *) self->doc);
2593 /* Add a new internal function. NAME is the name of the function; DOC
2594 is a documentation string describing the function. HANDLER is
2595 called when the function is invoked. COOKIE is an arbitrary
2596 pointer which is passed to HANDLER and is intended for "user
2599 add_internal_function (const char *name, const char *doc,
2600 internal_function_fn handler, void *cookie)
2602 struct cmd_list_element *cmd;
2603 struct internal_function *ifn;
2604 struct internalvar *var = lookup_internalvar (name);
2606 ifn = create_internal_function (name, handler, cookie);
2607 set_internalvar_function (var, ifn);
2609 cmd = add_cmd (xstrdup (name), no_class, function_command, (char *) doc,
2611 cmd->destroyer = function_destroyer;
2614 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
2615 prevent cycles / duplicates. */
2618 preserve_one_value (struct value *value, struct objfile *objfile,
2619 htab_t copied_types)
2621 if (TYPE_OBJFILE (value->type) == objfile)
2622 value->type = copy_type_recursive (objfile, value->type, copied_types);
2624 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
2625 value->enclosing_type = copy_type_recursive (objfile,
2626 value->enclosing_type,
2630 /* Likewise for internal variable VAR. */
2633 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
2634 htab_t copied_types)
2638 case INTERNALVAR_INTEGER:
2639 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
2641 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
2644 case INTERNALVAR_VALUE:
2645 preserve_one_value (var->u.value, objfile, copied_types);
2650 /* Update the internal variables and value history when OBJFILE is
2651 discarded; we must copy the types out of the objfile. New global types
2652 will be created for every convenience variable which currently points to
2653 this objfile's types, and the convenience variables will be adjusted to
2654 use the new global types. */
2657 preserve_values (struct objfile *objfile)
2659 htab_t copied_types;
2660 struct value_history_chunk *cur;
2661 struct internalvar *var;
2664 /* Create the hash table. We allocate on the objfile's obstack, since
2665 it is soon to be deleted. */
2666 copied_types = create_copied_types_hash (objfile);
2668 for (cur = value_history_chain; cur; cur = cur->next)
2669 for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
2671 preserve_one_value (cur->values[i], objfile, copied_types);
2673 for (var = internalvars; var; var = var->next)
2674 preserve_one_internalvar (var, objfile, copied_types);
2676 preserve_ext_lang_values (objfile, copied_types);
2678 htab_delete (copied_types);
2682 show_convenience (char *ignore, int from_tty)
2684 struct gdbarch *gdbarch = get_current_arch ();
2685 struct internalvar *var;
2687 struct value_print_options opts;
2689 get_user_print_options (&opts);
2690 for (var = internalvars; var; var = var->next)
2697 printf_filtered (("$%s = "), var->name);
2703 val = value_of_internalvar (gdbarch, var);
2704 value_print (val, gdb_stdout, &opts);
2706 CATCH (ex, RETURN_MASK_ERROR)
2708 fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
2712 printf_filtered (("\n"));
2716 /* This text does not mention convenience functions on purpose.
2717 The user can't create them except via Python, and if Python support
2718 is installed this message will never be printed ($_streq will
2720 printf_unfiltered (_("No debugger convenience variables now defined.\n"
2721 "Convenience variables have "
2722 "names starting with \"$\";\n"
2723 "use \"set\" as in \"set "
2724 "$foo = 5\" to define them.\n"));
2728 /* Return the TYPE_CODE_XMETHOD value corresponding to WORKER. */
2731 value_of_xmethod (struct xmethod_worker *worker)
2733 if (worker->value == NULL)
2737 v = allocate_value (builtin_type (target_gdbarch ())->xmethod);
2738 v->lval = lval_xcallable;
2739 v->location.xm_worker = worker;
2744 return worker->value;
2747 /* Return the type of the result of TYPE_CODE_XMETHOD value METHOD. */
2750 result_type_of_xmethod (struct value *method, int argc, struct value **argv)
2752 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2753 && method->lval == lval_xcallable && argc > 0);
2755 return get_xmethod_result_type (method->location.xm_worker,
2756 argv[0], argv + 1, argc - 1);
2759 /* Call the xmethod corresponding to the TYPE_CODE_XMETHOD value METHOD. */
2762 call_xmethod (struct value *method, int argc, struct value **argv)
2764 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2765 && method->lval == lval_xcallable && argc > 0);
2767 return invoke_xmethod (method->location.xm_worker,
2768 argv[0], argv + 1, argc - 1);
2771 /* Extract a value as a C number (either long or double).
2772 Knows how to convert fixed values to double, or
2773 floating values to long.
2774 Does not deallocate the value. */
2777 value_as_long (struct value *val)
2779 /* This coerces arrays and functions, which is necessary (e.g.
2780 in disassemble_command). It also dereferences references, which
2781 I suspect is the most logical thing to do. */
2782 val = coerce_array (val);
2783 return unpack_long (value_type (val), value_contents (val));
2787 value_as_double (struct value *val)
2792 foo = unpack_double (value_type (val), value_contents (val), &inv);
2794 error (_("Invalid floating value found in program."));
2798 /* Extract a value as a C pointer. Does not deallocate the value.
2799 Note that val's type may not actually be a pointer; value_as_long
2800 handles all the cases. */
2802 value_as_address (struct value *val)
2804 struct gdbarch *gdbarch = get_type_arch (value_type (val));
2806 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2807 whether we want this to be true eventually. */
2809 /* gdbarch_addr_bits_remove is wrong if we are being called for a
2810 non-address (e.g. argument to "signal", "info break", etc.), or
2811 for pointers to char, in which the low bits *are* significant. */
2812 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
2815 /* There are several targets (IA-64, PowerPC, and others) which
2816 don't represent pointers to functions as simply the address of
2817 the function's entry point. For example, on the IA-64, a
2818 function pointer points to a two-word descriptor, generated by
2819 the linker, which contains the function's entry point, and the
2820 value the IA-64 "global pointer" register should have --- to
2821 support position-independent code. The linker generates
2822 descriptors only for those functions whose addresses are taken.
2824 On such targets, it's difficult for GDB to convert an arbitrary
2825 function address into a function pointer; it has to either find
2826 an existing descriptor for that function, or call malloc and
2827 build its own. On some targets, it is impossible for GDB to
2828 build a descriptor at all: the descriptor must contain a jump
2829 instruction; data memory cannot be executed; and code memory
2832 Upon entry to this function, if VAL is a value of type `function'
2833 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2834 value_address (val) is the address of the function. This is what
2835 you'll get if you evaluate an expression like `main'. The call
2836 to COERCE_ARRAY below actually does all the usual unary
2837 conversions, which includes converting values of type `function'
2838 to `pointer to function'. This is the challenging conversion
2839 discussed above. Then, `unpack_long' will convert that pointer
2840 back into an address.
2842 So, suppose the user types `disassemble foo' on an architecture
2843 with a strange function pointer representation, on which GDB
2844 cannot build its own descriptors, and suppose further that `foo'
2845 has no linker-built descriptor. The address->pointer conversion
2846 will signal an error and prevent the command from running, even
2847 though the next step would have been to convert the pointer
2848 directly back into the same address.
2850 The following shortcut avoids this whole mess. If VAL is a
2851 function, just return its address directly. */
2852 if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
2853 || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
2854 return value_address (val);
2856 val = coerce_array (val);
2858 /* Some architectures (e.g. Harvard), map instruction and data
2859 addresses onto a single large unified address space. For
2860 instance: An architecture may consider a large integer in the
2861 range 0x10000000 .. 0x1000ffff to already represent a data
2862 addresses (hence not need a pointer to address conversion) while
2863 a small integer would still need to be converted integer to
2864 pointer to address. Just assume such architectures handle all
2865 integer conversions in a single function. */
2869 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2870 must admonish GDB hackers to make sure its behavior matches the
2871 compiler's, whenever possible.
2873 In general, I think GDB should evaluate expressions the same way
2874 the compiler does. When the user copies an expression out of
2875 their source code and hands it to a `print' command, they should
2876 get the same value the compiler would have computed. Any
2877 deviation from this rule can cause major confusion and annoyance,
2878 and needs to be justified carefully. In other words, GDB doesn't
2879 really have the freedom to do these conversions in clever and
2882 AndrewC pointed out that users aren't complaining about how GDB
2883 casts integers to pointers; they are complaining that they can't
2884 take an address from a disassembly listing and give it to `x/i'.
2885 This is certainly important.
2887 Adding an architecture method like integer_to_address() certainly
2888 makes it possible for GDB to "get it right" in all circumstances
2889 --- the target has complete control over how things get done, so
2890 people can Do The Right Thing for their target without breaking
2891 anyone else. The standard doesn't specify how integers get
2892 converted to pointers; usually, the ABI doesn't either, but
2893 ABI-specific code is a more reasonable place to handle it. */
2895 if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR
2896 && TYPE_CODE (value_type (val)) != TYPE_CODE_REF
2897 && gdbarch_integer_to_address_p (gdbarch))
2898 return gdbarch_integer_to_address (gdbarch, value_type (val),
2899 value_contents (val));
2901 return unpack_long (value_type (val), value_contents (val));
2905 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2906 as a long, or as a double, assuming the raw data is described
2907 by type TYPE. Knows how to convert different sizes of values
2908 and can convert between fixed and floating point. We don't assume
2909 any alignment for the raw data. Return value is in host byte order.
2911 If you want functions and arrays to be coerced to pointers, and
2912 references to be dereferenced, call value_as_long() instead.
2914 C++: It is assumed that the front-end has taken care of
2915 all matters concerning pointers to members. A pointer
2916 to member which reaches here is considered to be equivalent
2917 to an INT (or some size). After all, it is only an offset. */
2920 unpack_long (struct type *type, const gdb_byte *valaddr)
2922 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2923 enum type_code code = TYPE_CODE (type);
2924 int len = TYPE_LENGTH (type);
2925 int nosign = TYPE_UNSIGNED (type);
2929 case TYPE_CODE_TYPEDEF:
2930 return unpack_long (check_typedef (type), valaddr);
2931 case TYPE_CODE_ENUM:
2932 case TYPE_CODE_FLAGS:
2933 case TYPE_CODE_BOOL:
2935 case TYPE_CODE_CHAR:
2936 case TYPE_CODE_RANGE:
2937 case TYPE_CODE_MEMBERPTR:
2939 return extract_unsigned_integer (valaddr, len, byte_order);
2941 return extract_signed_integer (valaddr, len, byte_order);
2944 return (LONGEST) extract_typed_floating (valaddr, type);
2946 case TYPE_CODE_DECFLOAT:
2947 /* libdecnumber has a function to convert from decimal to integer, but
2948 it doesn't work when the decimal number has a fractional part. */
2949 return (LONGEST) decimal_to_doublest (valaddr, len, byte_order);
2953 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2954 whether we want this to be true eventually. */
2955 return extract_typed_address (valaddr, type);
2958 error (_("Value can't be converted to integer."));
2960 return 0; /* Placate lint. */
2963 /* Return a double value from the specified type and address.
2964 INVP points to an int which is set to 0 for valid value,
2965 1 for invalid value (bad float format). In either case,
2966 the returned double is OK to use. Argument is in target
2967 format, result is in host format. */
2970 unpack_double (struct type *type, const gdb_byte *valaddr, int *invp)
2972 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2973 enum type_code code;
2977 *invp = 0; /* Assume valid. */
2978 type = check_typedef (type);
2979 code = TYPE_CODE (type);
2980 len = TYPE_LENGTH (type);
2981 nosign = TYPE_UNSIGNED (type);
2982 if (code == TYPE_CODE_FLT)
2984 /* NOTE: cagney/2002-02-19: There was a test here to see if the
2985 floating-point value was valid (using the macro
2986 INVALID_FLOAT). That test/macro have been removed.
2988 It turns out that only the VAX defined this macro and then
2989 only in a non-portable way. Fixing the portability problem
2990 wouldn't help since the VAX floating-point code is also badly
2991 bit-rotten. The target needs to add definitions for the
2992 methods gdbarch_float_format and gdbarch_double_format - these
2993 exactly describe the target floating-point format. The
2994 problem here is that the corresponding floatformat_vax_f and
2995 floatformat_vax_d values these methods should be set to are
2996 also not defined either. Oops!
2998 Hopefully someone will add both the missing floatformat
2999 definitions and the new cases for floatformat_is_valid (). */
3001 if (!floatformat_is_valid (floatformat_from_type (type), valaddr))
3007 return extract_typed_floating (valaddr, type);
3009 else if (code == TYPE_CODE_DECFLOAT)
3010 return decimal_to_doublest (valaddr, len, byte_order);
3013 /* Unsigned -- be sure we compensate for signed LONGEST. */
3014 return (ULONGEST) unpack_long (type, valaddr);
3018 /* Signed -- we are OK with unpack_long. */
3019 return unpack_long (type, valaddr);
3023 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
3024 as a CORE_ADDR, assuming the raw data is described by type TYPE.
3025 We don't assume any alignment for the raw data. Return value is in
3028 If you want functions and arrays to be coerced to pointers, and
3029 references to be dereferenced, call value_as_address() instead.
3031 C++: It is assumed that the front-end has taken care of
3032 all matters concerning pointers to members. A pointer
3033 to member which reaches here is considered to be equivalent
3034 to an INT (or some size). After all, it is only an offset. */
3037 unpack_pointer (struct type *type, const gdb_byte *valaddr)
3039 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
3040 whether we want this to be true eventually. */
3041 return unpack_long (type, valaddr);
3045 /* Get the value of the FIELDNO'th field (which must be static) of
3049 value_static_field (struct type *type, int fieldno)
3051 struct value *retval;
3053 switch (TYPE_FIELD_LOC_KIND (type, fieldno))
3055 case FIELD_LOC_KIND_PHYSADDR:
3056 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
3057 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
3059 case FIELD_LOC_KIND_PHYSNAME:
3061 const char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
3062 /* TYPE_FIELD_NAME (type, fieldno); */
3063 struct block_symbol sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
3065 if (sym.symbol == NULL)
3067 /* With some compilers, e.g. HP aCC, static data members are
3068 reported as non-debuggable symbols. */
3069 struct bound_minimal_symbol msym
3070 = lookup_minimal_symbol (phys_name, NULL, NULL);
3073 return allocate_optimized_out_value (type);
3076 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
3077 BMSYMBOL_VALUE_ADDRESS (msym));
3081 retval = value_of_variable (sym.symbol, sym.block);
3085 gdb_assert_not_reached ("unexpected field location kind");
3091 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
3092 You have to be careful here, since the size of the data area for the value
3093 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
3094 than the old enclosing type, you have to allocate more space for the
3098 set_value_enclosing_type (struct value *val, struct type *new_encl_type)
3100 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
3102 check_type_length_before_alloc (new_encl_type);
3104 = (gdb_byte *) xrealloc (val->contents, TYPE_LENGTH (new_encl_type));
3107 val->enclosing_type = new_encl_type;
3110 /* Given a value ARG1 (offset by OFFSET bytes)
3111 of a struct or union type ARG_TYPE,
3112 extract and return the value of one of its (non-static) fields.
3113 FIELDNO says which field. */
3116 value_primitive_field (struct value *arg1, LONGEST offset,
3117 int fieldno, struct type *arg_type)
3121 struct gdbarch *arch = get_value_arch (arg1);
3122 int unit_size = gdbarch_addressable_memory_unit_size (arch);
3124 arg_type = check_typedef (arg_type);
3125 type = TYPE_FIELD_TYPE (arg_type, fieldno);
3127 /* Call check_typedef on our type to make sure that, if TYPE
3128 is a TYPE_CODE_TYPEDEF, its length is set to the length
3129 of the target type instead of zero. However, we do not
3130 replace the typedef type by the target type, because we want
3131 to keep the typedef in order to be able to print the type
3132 description correctly. */
3133 check_typedef (type);
3135 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
3137 /* Handle packed fields.
3139 Create a new value for the bitfield, with bitpos and bitsize
3140 set. If possible, arrange offset and bitpos so that we can
3141 do a single aligned read of the size of the containing type.
3142 Otherwise, adjust offset to the byte containing the first
3143 bit. Assume that the address, offset, and embedded offset
3144 are sufficiently aligned. */
3146 LONGEST bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
3147 LONGEST container_bitsize = TYPE_LENGTH (type) * 8;
3149 v = allocate_value_lazy (type);
3150 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
3151 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
3152 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
3153 v->bitpos = bitpos % container_bitsize;
3155 v->bitpos = bitpos % 8;
3156 v->offset = (value_embedded_offset (arg1)
3158 + (bitpos - v->bitpos) / 8);
3159 set_value_parent (v, arg1);
3160 if (!value_lazy (arg1))
3161 value_fetch_lazy (v);
3163 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
3165 /* This field is actually a base subobject, so preserve the
3166 entire object's contents for later references to virtual
3170 /* Lazy register values with offsets are not supported. */
3171 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3172 value_fetch_lazy (arg1);
3174 /* We special case virtual inheritance here because this
3175 requires access to the contents, which we would rather avoid
3176 for references to ordinary fields of unavailable values. */
3177 if (BASETYPE_VIA_VIRTUAL (arg_type, fieldno))
3178 boffset = baseclass_offset (arg_type, fieldno,
3179 value_contents (arg1),
3180 value_embedded_offset (arg1),
3181 value_address (arg1),
3184 boffset = TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
3186 if (value_lazy (arg1))
3187 v = allocate_value_lazy (value_enclosing_type (arg1));
3190 v = allocate_value (value_enclosing_type (arg1));
3191 value_contents_copy_raw (v, 0, arg1, 0,
3192 TYPE_LENGTH (value_enclosing_type (arg1)));
3195 v->offset = value_offset (arg1);
3196 v->embedded_offset = offset + value_embedded_offset (arg1) + boffset;
3198 else if (NULL != TYPE_DATA_LOCATION (type))
3200 /* Field is a dynamic data member. */
3202 gdb_assert (0 == offset);
3203 /* We expect an already resolved data location. */
3204 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (type));
3205 /* For dynamic data types defer memory allocation
3206 until we actual access the value. */
3207 v = allocate_value_lazy (type);
3211 /* Plain old data member */
3212 offset += (TYPE_FIELD_BITPOS (arg_type, fieldno)
3213 / (HOST_CHAR_BIT * unit_size));
3215 /* Lazy register values with offsets are not supported. */
3216 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3217 value_fetch_lazy (arg1);
3219 if (value_lazy (arg1))
3220 v = allocate_value_lazy (type);
3223 v = allocate_value (type);
3224 value_contents_copy_raw (v, value_embedded_offset (v),
3225 arg1, value_embedded_offset (arg1) + offset,
3226 type_length_units (type));
3228 v->offset = (value_offset (arg1) + offset
3229 + value_embedded_offset (arg1));
3231 set_value_component_location (v, arg1);
3232 VALUE_REGNUM (v) = VALUE_REGNUM (arg1);
3233 VALUE_NEXT_FRAME_ID (v) = VALUE_NEXT_FRAME_ID (arg1);
3237 /* Given a value ARG1 of a struct or union type,
3238 extract and return the value of one of its (non-static) fields.
3239 FIELDNO says which field. */
3242 value_field (struct value *arg1, int fieldno)
3244 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
3247 /* Return a non-virtual function as a value.
3248 F is the list of member functions which contains the desired method.
3249 J is an index into F which provides the desired method.
3251 We only use the symbol for its address, so be happy with either a
3252 full symbol or a minimal symbol. */
3255 value_fn_field (struct value **arg1p, struct fn_field *f,
3256 int j, struct type *type,
3260 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
3261 const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
3263 struct bound_minimal_symbol msym;
3265 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0).symbol;
3268 memset (&msym, 0, sizeof (msym));
3272 gdb_assert (sym == NULL);
3273 msym = lookup_bound_minimal_symbol (physname);
3274 if (msym.minsym == NULL)
3278 v = allocate_value (ftype);
3281 set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (sym)));
3285 /* The minimal symbol might point to a function descriptor;
3286 resolve it to the actual code address instead. */
3287 struct objfile *objfile = msym.objfile;
3288 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3290 set_value_address (v,
3291 gdbarch_convert_from_func_ptr_addr
3292 (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), ¤t_target));
3297 if (type != value_type (*arg1p))
3298 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
3299 value_addr (*arg1p)));
3301 /* Move the `this' pointer according to the offset.
3302 VALUE_OFFSET (*arg1p) += offset; */
3310 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at
3311 VALADDR, and store the result in *RESULT.
3312 The bitfield starts at BITPOS bits and contains BITSIZE bits.
3314 Extracting bits depends on endianness of the machine. Compute the
3315 number of least significant bits to discard. For big endian machines,
3316 we compute the total number of bits in the anonymous object, subtract
3317 off the bit count from the MSB of the object to the MSB of the
3318 bitfield, then the size of the bitfield, which leaves the LSB discard
3319 count. For little endian machines, the discard count is simply the
3320 number of bits from the LSB of the anonymous object to the LSB of the
3323 If the field is signed, we also do sign extension. */
3326 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
3327 LONGEST bitpos, LONGEST bitsize)
3329 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
3334 LONGEST read_offset;
3336 /* Read the minimum number of bytes required; there may not be
3337 enough bytes to read an entire ULONGEST. */
3338 field_type = check_typedef (field_type);
3340 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
3342 bytes_read = TYPE_LENGTH (field_type);
3344 read_offset = bitpos / 8;
3346 val = extract_unsigned_integer (valaddr + read_offset,
3347 bytes_read, byte_order);
3349 /* Extract bits. See comment above. */
3351 if (gdbarch_bits_big_endian (get_type_arch (field_type)))
3352 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
3354 lsbcount = (bitpos % 8);
3357 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
3358 If the field is signed, and is negative, then sign extend. */
3360 if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val)))
3362 valmask = (((ULONGEST) 1) << bitsize) - 1;
3364 if (!TYPE_UNSIGNED (field_type))
3366 if (val & (valmask ^ (valmask >> 1)))
3376 /* Unpack a field FIELDNO of the specified TYPE, from the object at
3377 VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
3378 ORIGINAL_VALUE, which must not be NULL. See
3379 unpack_value_bits_as_long for more details. */
3382 unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
3383 LONGEST embedded_offset, int fieldno,
3384 const struct value *val, LONGEST *result)
3386 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3387 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3388 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3391 gdb_assert (val != NULL);
3393 bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3394 if (value_bits_any_optimized_out (val, bit_offset, bitsize)
3395 || !value_bits_available (val, bit_offset, bitsize))
3398 *result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3403 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous
3404 object at VALADDR. See unpack_bits_as_long for more details. */
3407 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
3409 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3410 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3411 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3413 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
3416 /* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
3417 VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
3418 the contents in DEST_VAL, zero or sign extending if the type of
3419 DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
3420 VAL. If the VAL's contents required to extract the bitfield from
3421 are unavailable/optimized out, DEST_VAL is correspondingly
3422 marked unavailable/optimized out. */
3425 unpack_value_bitfield (struct value *dest_val,
3426 LONGEST bitpos, LONGEST bitsize,
3427 const gdb_byte *valaddr, LONGEST embedded_offset,
3428 const struct value *val)
3430 enum bfd_endian byte_order;
3433 struct type *field_type = value_type (dest_val);
3435 byte_order = gdbarch_byte_order (get_type_arch (field_type));
3437 /* First, unpack and sign extend the bitfield as if it was wholly
3438 valid. Optimized out/unavailable bits are read as zero, but
3439 that's OK, as they'll end up marked below. If the VAL is
3440 wholly-invalid we may have skipped allocating its contents,
3441 though. See allocate_optimized_out_value. */
3442 if (valaddr != NULL)
3446 num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3448 store_signed_integer (value_contents_raw (dest_val),
3449 TYPE_LENGTH (field_type), byte_order, num);
3452 /* Now copy the optimized out / unavailability ranges to the right
3454 src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3455 if (byte_order == BFD_ENDIAN_BIG)
3456 dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
3459 value_ranges_copy_adjusted (dest_val, dst_bit_offset,
3460 val, src_bit_offset, bitsize);
3463 /* Return a new value with type TYPE, which is FIELDNO field of the
3464 object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
3465 of VAL. If the VAL's contents required to extract the bitfield
3466 from are unavailable/optimized out, the new value is
3467 correspondingly marked unavailable/optimized out. */
3470 value_field_bitfield (struct type *type, int fieldno,
3471 const gdb_byte *valaddr,
3472 LONGEST embedded_offset, const struct value *val)
3474 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3475 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3476 struct value *res_val = allocate_value (TYPE_FIELD_TYPE (type, fieldno));
3478 unpack_value_bitfield (res_val, bitpos, bitsize,
3479 valaddr, embedded_offset, val);
3484 /* Modify the value of a bitfield. ADDR points to a block of memory in
3485 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
3486 is the desired value of the field, in host byte order. BITPOS and BITSIZE
3487 indicate which bits (in target bit order) comprise the bitfield.
3488 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
3489 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
3492 modify_field (struct type *type, gdb_byte *addr,
3493 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
3495 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3497 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
3500 /* Normalize BITPOS. */
3504 /* If a negative fieldval fits in the field in question, chop
3505 off the sign extension bits. */
3506 if ((~fieldval & ~(mask >> 1)) == 0)
3509 /* Warn if value is too big to fit in the field in question. */
3510 if (0 != (fieldval & ~mask))
3512 /* FIXME: would like to include fieldval in the message, but
3513 we don't have a sprintf_longest. */
3514 warning (_("Value does not fit in %s bits."), plongest (bitsize));
3516 /* Truncate it, otherwise adjoining fields may be corrupted. */
3520 /* Ensure no bytes outside of the modified ones get accessed as it may cause
3521 false valgrind reports. */
3523 bytesize = (bitpos + bitsize + 7) / 8;
3524 oword = extract_unsigned_integer (addr, bytesize, byte_order);
3526 /* Shifting for bit field depends on endianness of the target machine. */
3527 if (gdbarch_bits_big_endian (get_type_arch (type)))
3528 bitpos = bytesize * 8 - bitpos - bitsize;
3530 oword &= ~(mask << bitpos);
3531 oword |= fieldval << bitpos;
3533 store_unsigned_integer (addr, bytesize, byte_order, oword);
3536 /* Pack NUM into BUF using a target format of TYPE. */
3539 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
3541 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3544 type = check_typedef (type);
3545 len = TYPE_LENGTH (type);
3547 switch (TYPE_CODE (type))
3550 case TYPE_CODE_CHAR:
3551 case TYPE_CODE_ENUM:
3552 case TYPE_CODE_FLAGS:
3553 case TYPE_CODE_BOOL:
3554 case TYPE_CODE_RANGE:
3555 case TYPE_CODE_MEMBERPTR:
3556 store_signed_integer (buf, len, byte_order, num);
3561 store_typed_address (buf, type, (CORE_ADDR) num);
3565 error (_("Unexpected type (%d) encountered for integer constant."),
3571 /* Pack NUM into BUF using a target format of TYPE. */
3574 pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
3577 enum bfd_endian byte_order;
3579 type = check_typedef (type);
3580 len = TYPE_LENGTH (type);
3581 byte_order = gdbarch_byte_order (get_type_arch (type));
3583 switch (TYPE_CODE (type))
3586 case TYPE_CODE_CHAR:
3587 case TYPE_CODE_ENUM:
3588 case TYPE_CODE_FLAGS:
3589 case TYPE_CODE_BOOL:
3590 case TYPE_CODE_RANGE:
3591 case TYPE_CODE_MEMBERPTR:
3592 store_unsigned_integer (buf, len, byte_order, num);
3597 store_typed_address (buf, type, (CORE_ADDR) num);
3601 error (_("Unexpected type (%d) encountered "
3602 "for unsigned integer constant."),
3608 /* Convert C numbers into newly allocated values. */
3611 value_from_longest (struct type *type, LONGEST num)
3613 struct value *val = allocate_value (type);
3615 pack_long (value_contents_raw (val), type, num);
3620 /* Convert C unsigned numbers into newly allocated values. */
3623 value_from_ulongest (struct type *type, ULONGEST num)
3625 struct value *val = allocate_value (type);
3627 pack_unsigned_long (value_contents_raw (val), type, num);
3633 /* Create a value representing a pointer of type TYPE to the address
3637 value_from_pointer (struct type *type, CORE_ADDR addr)
3639 struct value *val = allocate_value (type);
3641 store_typed_address (value_contents_raw (val),
3642 check_typedef (type), addr);
3647 /* Create a value of type TYPE whose contents come from VALADDR, if it
3648 is non-null, and whose memory address (in the inferior) is
3649 ADDRESS. The type of the created value may differ from the passed
3650 type TYPE. Make sure to retrieve values new type after this call.
3651 Note that TYPE is not passed through resolve_dynamic_type; this is
3652 a special API intended for use only by Ada. */
3655 value_from_contents_and_address_unresolved (struct type *type,
3656 const gdb_byte *valaddr,
3661 if (valaddr == NULL)
3662 v = allocate_value_lazy (type);
3664 v = value_from_contents (type, valaddr);
3665 set_value_address (v, address);
3666 VALUE_LVAL (v) = lval_memory;
3670 /* Create a value of type TYPE whose contents come from VALADDR, if it
3671 is non-null, and whose memory address (in the inferior) is
3672 ADDRESS. The type of the created value may differ from the passed
3673 type TYPE. Make sure to retrieve values new type after this call. */
3676 value_from_contents_and_address (struct type *type,
3677 const gdb_byte *valaddr,
3680 struct type *resolved_type = resolve_dynamic_type (type, valaddr, address);
3681 struct type *resolved_type_no_typedef = check_typedef (resolved_type);
3684 if (valaddr == NULL)
3685 v = allocate_value_lazy (resolved_type);
3687 v = value_from_contents (resolved_type, valaddr);
3688 if (TYPE_DATA_LOCATION (resolved_type_no_typedef) != NULL
3689 && TYPE_DATA_LOCATION_KIND (resolved_type_no_typedef) == PROP_CONST)
3690 address = TYPE_DATA_LOCATION_ADDR (resolved_type_no_typedef);
3691 set_value_address (v, address);
3692 VALUE_LVAL (v) = lval_memory;
3696 /* Create a value of type TYPE holding the contents CONTENTS.
3697 The new value is `not_lval'. */
3700 value_from_contents (struct type *type, const gdb_byte *contents)
3702 struct value *result;
3704 result = allocate_value (type);
3705 memcpy (value_contents_raw (result), contents, TYPE_LENGTH (type));
3710 value_from_double (struct type *type, DOUBLEST num)
3712 struct value *val = allocate_value (type);
3713 struct type *base_type = check_typedef (type);
3714 enum type_code code = TYPE_CODE (base_type);
3716 if (code == TYPE_CODE_FLT)
3718 store_typed_floating (value_contents_raw (val), base_type, num);
3721 error (_("Unexpected type encountered for floating constant."));
3727 value_from_decfloat (struct type *type, const gdb_byte *dec)
3729 struct value *val = allocate_value (type);
3731 memcpy (value_contents_raw (val), dec, TYPE_LENGTH (type));
3735 /* Extract a value from the history file. Input will be of the form
3736 $digits or $$digits. See block comment above 'write_dollar_variable'
3740 value_from_history_ref (const char *h, const char **endp)
3752 /* Find length of numeral string. */
3753 for (; isdigit (h[len]); len++)
3756 /* Make sure numeral string is not part of an identifier. */
3757 if (h[len] == '_' || isalpha (h[len]))
3760 /* Now collect the index value. */
3765 /* For some bizarre reason, "$$" is equivalent to "$$1",
3766 rather than to "$$0" as it ought to be! */
3774 index = -strtol (&h[2], &local_end, 10);
3782 /* "$" is equivalent to "$0". */
3790 index = strtol (&h[1], &local_end, 10);
3795 return access_value_history (index);
3798 /* Get the component value (offset by OFFSET bytes) of a struct or
3799 union WHOLE. Component's type is TYPE. */
3802 value_from_component (struct value *whole, struct type *type, LONGEST offset)
3806 if (VALUE_LVAL (whole) == lval_memory && value_lazy (whole))
3807 v = allocate_value_lazy (type);
3810 v = allocate_value (type);
3811 value_contents_copy (v, value_embedded_offset (v),
3812 whole, value_embedded_offset (whole) + offset,
3813 type_length_units (type));
3815 v->offset = value_offset (whole) + offset + value_embedded_offset (whole);
3816 set_value_component_location (v, whole);
3817 VALUE_REGNUM (v) = VALUE_REGNUM (whole);
3818 VALUE_NEXT_FRAME_ID (v) = VALUE_NEXT_FRAME_ID (whole);
3824 coerce_ref_if_computed (const struct value *arg)
3826 const struct lval_funcs *funcs;
3828 if (TYPE_CODE (check_typedef (value_type (arg))) != TYPE_CODE_REF)
3831 if (value_lval_const (arg) != lval_computed)
3834 funcs = value_computed_funcs (arg);
3835 if (funcs->coerce_ref == NULL)
3838 return funcs->coerce_ref (arg);
3841 /* Look at value.h for description. */
3844 readjust_indirect_value_type (struct value *value, struct type *enc_type,
3845 const struct type *original_type,
3846 const struct value *original_value)
3848 /* Re-adjust type. */
3849 deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
3851 /* Add embedding info. */
3852 set_value_enclosing_type (value, enc_type);
3853 set_value_embedded_offset (value, value_pointed_to_offset (original_value));
3855 /* We may be pointing to an object of some derived type. */
3856 return value_full_object (value, NULL, 0, 0, 0);
3860 coerce_ref (struct value *arg)
3862 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
3863 struct value *retval;
3864 struct type *enc_type;
3866 retval = coerce_ref_if_computed (arg);
3870 if (TYPE_CODE (value_type_arg_tmp) != TYPE_CODE_REF)
3873 enc_type = check_typedef (value_enclosing_type (arg));
3874 enc_type = TYPE_TARGET_TYPE (enc_type);
3876 retval = value_at_lazy (enc_type,
3877 unpack_pointer (value_type (arg),
3878 value_contents (arg)));
3879 enc_type = value_type (retval);
3880 return readjust_indirect_value_type (retval, enc_type,
3881 value_type_arg_tmp, arg);
3885 coerce_array (struct value *arg)
3889 arg = coerce_ref (arg);
3890 type = check_typedef (value_type (arg));
3892 switch (TYPE_CODE (type))
3894 case TYPE_CODE_ARRAY:
3895 if (!TYPE_VECTOR (type) && current_language->c_style_arrays)
3896 arg = value_coerce_array (arg);
3898 case TYPE_CODE_FUNC:
3899 arg = value_coerce_function (arg);
3906 /* Return the return value convention that will be used for the
3909 enum return_value_convention
3910 struct_return_convention (struct gdbarch *gdbarch,
3911 struct value *function, struct type *value_type)
3913 enum type_code code = TYPE_CODE (value_type);
3915 if (code == TYPE_CODE_ERROR)
3916 error (_("Function return type unknown."));
3918 /* Probe the architecture for the return-value convention. */
3919 return gdbarch_return_value (gdbarch, function, value_type,
3923 /* Return true if the function returning the specified type is using
3924 the convention of returning structures in memory (passing in the
3925 address as a hidden first parameter). */
3928 using_struct_return (struct gdbarch *gdbarch,
3929 struct value *function, struct type *value_type)
3931 if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
3932 /* A void return value is never in memory. See also corresponding
3933 code in "print_return_value". */
3936 return (struct_return_convention (gdbarch, function, value_type)
3937 != RETURN_VALUE_REGISTER_CONVENTION);
3940 /* Set the initialized field in a value struct. */
3943 set_value_initialized (struct value *val, int status)
3945 val->initialized = status;
3948 /* Return the initialized field in a value struct. */
3951 value_initialized (const struct value *val)
3953 return val->initialized;
3956 /* Load the actual content of a lazy value. Fetch the data from the
3957 user's process and clear the lazy flag to indicate that the data in
3958 the buffer is valid.
3960 If the value is zero-length, we avoid calling read_memory, which
3961 would abort. We mark the value as fetched anyway -- all 0 bytes of
3965 value_fetch_lazy (struct value *val)
3967 gdb_assert (value_lazy (val));
3968 allocate_value_contents (val);
3969 /* A value is either lazy, or fully fetched. The
3970 availability/validity is only established as we try to fetch a
3972 gdb_assert (VEC_empty (range_s, val->optimized_out));
3973 gdb_assert (VEC_empty (range_s, val->unavailable));
3974 if (value_bitsize (val))
3976 /* To read a lazy bitfield, read the entire enclosing value. This
3977 prevents reading the same block of (possibly volatile) memory once
3978 per bitfield. It would be even better to read only the containing
3979 word, but we have no way to record that just specific bits of a
3980 value have been fetched. */
3981 struct type *type = check_typedef (value_type (val));
3982 struct value *parent = value_parent (val);
3984 if (value_lazy (parent))
3985 value_fetch_lazy (parent);
3987 unpack_value_bitfield (val,
3988 value_bitpos (val), value_bitsize (val),
3989 value_contents_for_printing (parent),
3990 value_offset (val), parent);
3992 else if (VALUE_LVAL (val) == lval_memory)
3994 CORE_ADDR addr = value_address (val);
3995 struct type *type = check_typedef (value_enclosing_type (val));
3997 if (TYPE_LENGTH (type))
3998 read_value_memory (val, 0, value_stack (val),
3999 addr, value_contents_all_raw (val),
4000 type_length_units (type));
4002 else if (VALUE_LVAL (val) == lval_register)
4004 struct frame_info *next_frame;
4006 struct type *type = check_typedef (value_type (val));
4007 struct value *new_val = val, *mark = value_mark ();
4009 /* Offsets are not supported here; lazy register values must
4010 refer to the entire register. */
4011 gdb_assert (value_offset (val) == 0);
4013 while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
4015 struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
4017 next_frame = frame_find_by_id (next_frame_id);
4018 regnum = VALUE_REGNUM (new_val);
4020 gdb_assert (next_frame != NULL);
4022 /* Convertible register routines are used for multi-register
4023 values and for interpretation in different types
4024 (e.g. float or int from a double register). Lazy
4025 register values should have the register's natural type,
4026 so they do not apply. */
4027 gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
4030 /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
4031 Since a "->next" operation was performed when setting
4032 this field, we do not need to perform a "next" operation
4033 again when unwinding the register. That's why
4034 frame_unwind_register_value() is called here instead of
4035 get_frame_register_value(). */
4036 new_val = frame_unwind_register_value (next_frame, regnum);
4038 /* If we get another lazy lval_register value, it means the
4039 register is found by reading it from NEXT_FRAME's next frame.
4040 frame_unwind_register_value should never return a value with
4041 the frame id pointing to NEXT_FRAME. If it does, it means we
4042 either have two consecutive frames with the same frame id
4043 in the frame chain, or some code is trying to unwind
4044 behind get_prev_frame's back (e.g., a frame unwind
4045 sniffer trying to unwind), bypassing its validations. In
4046 any case, it should always be an internal error to end up
4047 in this situation. */
4048 if (VALUE_LVAL (new_val) == lval_register
4049 && value_lazy (new_val)
4050 && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
4051 internal_error (__FILE__, __LINE__,
4052 _("infinite loop while fetching a register"));
4055 /* If it's still lazy (for instance, a saved register on the
4056 stack), fetch it. */
4057 if (value_lazy (new_val))
4058 value_fetch_lazy (new_val);
4060 /* Copy the contents and the unavailability/optimized-out
4061 meta-data from NEW_VAL to VAL. */
4062 set_value_lazy (val, 0);
4063 value_contents_copy (val, value_embedded_offset (val),
4064 new_val, value_embedded_offset (new_val),
4065 type_length_units (type));
4069 struct gdbarch *gdbarch;
4070 struct frame_info *frame;
4071 /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
4072 so that the frame level will be shown correctly. */
4073 frame = frame_find_by_id (VALUE_FRAME_ID (val));
4074 regnum = VALUE_REGNUM (val);
4075 gdbarch = get_frame_arch (frame);
4077 fprintf_unfiltered (gdb_stdlog,
4078 "{ value_fetch_lazy "
4079 "(frame=%d,regnum=%d(%s),...) ",
4080 frame_relative_level (frame), regnum,
4081 user_reg_map_regnum_to_name (gdbarch, regnum));
4083 fprintf_unfiltered (gdb_stdlog, "->");
4084 if (value_optimized_out (new_val))
4086 fprintf_unfiltered (gdb_stdlog, " ");
4087 val_print_optimized_out (new_val, gdb_stdlog);
4092 const gdb_byte *buf = value_contents (new_val);
4094 if (VALUE_LVAL (new_val) == lval_register)
4095 fprintf_unfiltered (gdb_stdlog, " register=%d",
4096 VALUE_REGNUM (new_val));
4097 else if (VALUE_LVAL (new_val) == lval_memory)
4098 fprintf_unfiltered (gdb_stdlog, " address=%s",
4100 value_address (new_val)));
4102 fprintf_unfiltered (gdb_stdlog, " computed");
4104 fprintf_unfiltered (gdb_stdlog, " bytes=");
4105 fprintf_unfiltered (gdb_stdlog, "[");
4106 for (i = 0; i < register_size (gdbarch, regnum); i++)
4107 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
4108 fprintf_unfiltered (gdb_stdlog, "]");
4111 fprintf_unfiltered (gdb_stdlog, " }\n");
4114 /* Dispose of the intermediate values. This prevents
4115 watchpoints from trying to watch the saved frame pointer. */
4116 value_free_to_mark (mark);
4118 else if (VALUE_LVAL (val) == lval_computed
4119 && value_computed_funcs (val)->read != NULL)
4120 value_computed_funcs (val)->read (val);
4122 internal_error (__FILE__, __LINE__, _("Unexpected lazy value type."));
4124 set_value_lazy (val, 0);
4127 /* Implementation of the convenience function $_isvoid. */
4129 static struct value *
4130 isvoid_internal_fn (struct gdbarch *gdbarch,
4131 const struct language_defn *language,
4132 void *cookie, int argc, struct value **argv)
4137 error (_("You must provide one argument for $_isvoid."));
4139 ret = TYPE_CODE (value_type (argv[0])) == TYPE_CODE_VOID;
4141 return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
4145 _initialize_values (void)
4147 add_cmd ("convenience", no_class, show_convenience, _("\
4148 Debugger convenience (\"$foo\") variables and functions.\n\
4149 Convenience variables are created when you assign them values;\n\
4150 thus, \"set $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
4152 A few convenience variables are given values automatically:\n\
4153 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
4154 \"$__\" holds the contents of the last address examined with \"x\"."
4157 Convenience functions are defined via the Python API."
4160 add_alias_cmd ("conv", "convenience", no_class, 1, &showlist);
4162 add_cmd ("values", no_set_class, show_values, _("\
4163 Elements of value history around item number IDX (or last ten)."),
4166 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
4167 Initialize a convenience variable if necessary.\n\
4168 init-if-undefined VARIABLE = EXPRESSION\n\
4169 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
4170 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
4171 VARIABLE is already initialized."));
4173 add_prefix_cmd ("function", no_class, function_command, _("\
4174 Placeholder command for showing help on convenience functions."),
4175 &functionlist, "function ", 0, &cmdlist);
4177 add_internal_function ("_isvoid", _("\
4178 Check whether an expression is void.\n\
4179 Usage: $_isvoid (expression)\n\
4180 Return 1 if the expression is void, zero otherwise."),
4181 isvoid_internal_fn, NULL);
4183 add_setshow_zuinteger_unlimited_cmd ("max-value-size",
4184 class_support, &max_value_size, _("\
4185 Set maximum sized value gdb will load from the inferior."), _("\
4186 Show maximum sized value gdb will load from the inferior."), _("\
4187 Use this to control the maximum size, in bytes, of a value that gdb\n\
4188 will load from the inferior. Setting this value to 'unlimited'\n\
4189 disables checking.\n\
4190 Setting this does not invalidate already allocated values, it only\n\
4191 prevents future values, larger than this size, from being allocated."),
4193 show_max_value_size,
4194 &setlist, &showlist);