1 /* Low level packing and unpacking of values for GDB, the GNU Debugger.
3 Copyright (C) 1986-2017 Free Software Foundation, Inc.
5 This file is part of GDB.
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21 #include "arch-utils.h"
33 #include "target-float.h"
36 #include "cli/cli-decode.h"
37 #include "extension.h"
39 #include "tracepoint.h"
41 #include "user-regs.h"
43 #include "completer.h"
45 /* Definition of a user function. */
46 struct internal_function
48 /* The name of the function. It is a bit odd to have this in the
49 function itself -- the user might use a differently-named
50 convenience variable to hold the function. */
54 internal_function_fn handler;
56 /* User data for the handler. */
60 /* Defines an [OFFSET, OFFSET + LENGTH) range. */
64 /* Lowest offset in the range. */
67 /* Length of the range. */
71 typedef struct range range_s;
75 /* Returns true if the ranges defined by [offset1, offset1+len1) and
76 [offset2, offset2+len2) overlap. */
79 ranges_overlap (LONGEST offset1, LONGEST len1,
80 LONGEST offset2, LONGEST len2)
84 l = std::max (offset1, offset2);
85 h = std::min (offset1 + len1, offset2 + len2);
89 /* Returns true if the first argument is strictly less than the
90 second, useful for VEC_lower_bound. We keep ranges sorted by
91 offset and coalesce overlapping and contiguous ranges, so this just
92 compares the starting offset. */
95 range_lessthan (const range_s *r1, const range_s *r2)
97 return r1->offset < r2->offset;
100 /* Returns true if RANGES contains any range that overlaps [OFFSET,
104 ranges_contain (VEC(range_s) *ranges, LONGEST offset, LONGEST length)
109 what.offset = offset;
110 what.length = length;
112 /* We keep ranges sorted by offset and coalesce overlapping and
113 contiguous ranges, so to check if a range list contains a given
114 range, we can do a binary search for the position the given range
115 would be inserted if we only considered the starting OFFSET of
116 ranges. We call that position I. Since we also have LENGTH to
117 care for (this is a range afterall), we need to check if the
118 _previous_ range overlaps the I range. E.g.,
122 |---| |---| |------| ... |--|
127 In the case above, the binary search would return `I=1', meaning,
128 this OFFSET should be inserted at position 1, and the current
129 position 1 should be pushed further (and before 2). But, `0'
132 Then we need to check if the I range overlaps the I range itself.
137 |---| |---| |-------| ... |--|
143 i = VEC_lower_bound (range_s, ranges, &what, range_lessthan);
147 struct range *bef = VEC_index (range_s, ranges, i - 1);
149 if (ranges_overlap (bef->offset, bef->length, offset, length))
153 if (i < VEC_length (range_s, ranges))
155 struct range *r = VEC_index (range_s, ranges, i);
157 if (ranges_overlap (r->offset, r->length, offset, length))
164 static struct cmd_list_element *functionlist;
166 /* Note that the fields in this structure are arranged to save a bit
171 /* Type of value; either not an lval, or one of the various
172 different possible kinds of lval. */
175 /* Is it modifiable? Only relevant if lval != not_lval. */
176 unsigned int modifiable : 1;
178 /* If zero, contents of this value are in the contents field. If
179 nonzero, contents are in inferior. If the lval field is lval_memory,
180 the contents are in inferior memory at location.address plus offset.
181 The lval field may also be lval_register.
183 WARNING: This field is used by the code which handles watchpoints
184 (see breakpoint.c) to decide whether a particular value can be
185 watched by hardware watchpoints. If the lazy flag is set for
186 some member of a value chain, it is assumed that this member of
187 the chain doesn't need to be watched as part of watching the
188 value itself. This is how GDB avoids watching the entire struct
189 or array when the user wants to watch a single struct member or
190 array element. If you ever change the way lazy flag is set and
191 reset, be sure to consider this use as well! */
192 unsigned int lazy : 1;
194 /* If value is a variable, is it initialized or not. */
195 unsigned int initialized : 1;
197 /* If value is from the stack. If this is set, read_stack will be
198 used instead of read_memory to enable extra caching. */
199 unsigned int stack : 1;
201 /* If the value has been released. */
202 unsigned int released : 1;
204 /* Location of value (if lval). */
207 /* If lval == lval_memory, this is the address in the inferior */
210 /*If lval == lval_register, the value is from a register. */
213 /* Register number. */
215 /* Frame ID of "next" frame to which a register value is relative.
216 If the register value is found relative to frame F, then the
217 frame id of F->next will be stored in next_frame_id. */
218 struct frame_id next_frame_id;
221 /* Pointer to internal variable. */
222 struct internalvar *internalvar;
224 /* Pointer to xmethod worker. */
225 struct xmethod_worker *xm_worker;
227 /* If lval == lval_computed, this is a set of function pointers
228 to use to access and describe the value, and a closure pointer
232 /* Functions to call. */
233 const struct lval_funcs *funcs;
235 /* Closure for those functions to use. */
240 /* Describes offset of a value within lval of a structure in target
241 addressable memory units. Note also the member embedded_offset
245 /* Only used for bitfields; number of bits contained in them. */
248 /* Only used for bitfields; position of start of field. For
249 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
250 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
253 /* The number of references to this value. When a value is created,
254 the value chain holds a reference, so REFERENCE_COUNT is 1. If
255 release_value is called, this value is removed from the chain but
256 the caller of release_value now has a reference to this value.
257 The caller must arrange for a call to value_free later. */
260 /* Only used for bitfields; the containing value. This allows a
261 single read from the target when displaying multiple
263 struct value *parent;
265 /* Type of the value. */
268 /* If a value represents a C++ object, then the `type' field gives
269 the object's compile-time type. If the object actually belongs
270 to some class derived from `type', perhaps with other base
271 classes and additional members, then `type' is just a subobject
272 of the real thing, and the full object is probably larger than
273 `type' would suggest.
275 If `type' is a dynamic class (i.e. one with a vtable), then GDB
276 can actually determine the object's run-time type by looking at
277 the run-time type information in the vtable. When this
278 information is available, we may elect to read in the entire
279 object, for several reasons:
281 - When printing the value, the user would probably rather see the
282 full object, not just the limited portion apparent from the
285 - If `type' has virtual base classes, then even printing `type'
286 alone may require reaching outside the `type' portion of the
287 object to wherever the virtual base class has been stored.
289 When we store the entire object, `enclosing_type' is the run-time
290 type -- the complete object -- and `embedded_offset' is the
291 offset of `type' within that larger type, in target addressable memory
292 units. The value_contents() macro takes `embedded_offset' into account,
293 so most GDB code continues to see the `type' portion of the value, just
294 as the inferior would.
296 If `type' is a pointer to an object, then `enclosing_type' is a
297 pointer to the object's run-time type, and `pointed_to_offset' is
298 the offset in target addressable memory units from the full object
299 to the pointed-to object -- that is, the value `embedded_offset' would
300 have if we followed the pointer and fetched the complete object.
301 (I don't really see the point. Why not just determine the
302 run-time type when you indirect, and avoid the special case? The
303 contents don't matter until you indirect anyway.)
305 If we're not doing anything fancy, `enclosing_type' is equal to
306 `type', and `embedded_offset' is zero, so everything works
308 struct type *enclosing_type;
309 LONGEST embedded_offset;
310 LONGEST pointed_to_offset;
312 /* Values are stored in a chain, so that they can be deleted easily
313 over calls to the inferior. Values assigned to internal
314 variables, put into the value history or exposed to Python are
315 taken off this list. */
318 /* Actual contents of the value. Target byte-order. NULL or not
319 valid if lazy is nonzero. */
322 /* Unavailable ranges in CONTENTS. We mark unavailable ranges,
323 rather than available, since the common and default case is for a
324 value to be available. This is filled in at value read time.
325 The unavailable ranges are tracked in bits. Note that a contents
326 bit that has been optimized out doesn't really exist in the
327 program, so it can't be marked unavailable either. */
328 VEC(range_s) *unavailable;
330 /* Likewise, but for optimized out contents (a chunk of the value of
331 a variable that does not actually exist in the program). If LVAL
332 is lval_register, this is a register ($pc, $sp, etc., never a
333 program variable) that has not been saved in the frame. Not
334 saved registers and optimized-out program variables values are
335 treated pretty much the same, except not-saved registers have a
336 different string representation and related error strings. */
337 VEC(range_s) *optimized_out;
343 get_value_arch (const struct value *value)
345 return get_type_arch (value_type (value));
349 value_bits_available (const struct value *value, LONGEST offset, LONGEST length)
351 gdb_assert (!value->lazy);
353 return !ranges_contain (value->unavailable, offset, length);
357 value_bytes_available (const struct value *value,
358 LONGEST offset, LONGEST length)
360 return value_bits_available (value,
361 offset * TARGET_CHAR_BIT,
362 length * TARGET_CHAR_BIT);
366 value_bits_any_optimized_out (const struct value *value, int bit_offset, int bit_length)
368 gdb_assert (!value->lazy);
370 return ranges_contain (value->optimized_out, bit_offset, bit_length);
374 value_entirely_available (struct value *value)
376 /* We can only tell whether the whole value is available when we try
379 value_fetch_lazy (value);
381 if (VEC_empty (range_s, value->unavailable))
386 /* Returns true if VALUE is entirely covered by RANGES. If the value
387 is lazy, it'll be read now. Note that RANGE is a pointer to
388 pointer because reading the value might change *RANGE. */
391 value_entirely_covered_by_range_vector (struct value *value,
392 VEC(range_s) **ranges)
394 /* We can only tell whether the whole value is optimized out /
395 unavailable when we try to read it. */
397 value_fetch_lazy (value);
399 if (VEC_length (range_s, *ranges) == 1)
401 struct range *t = VEC_index (range_s, *ranges, 0);
404 && t->length == (TARGET_CHAR_BIT
405 * TYPE_LENGTH (value_enclosing_type (value))))
413 value_entirely_unavailable (struct value *value)
415 return value_entirely_covered_by_range_vector (value, &value->unavailable);
419 value_entirely_optimized_out (struct value *value)
421 return value_entirely_covered_by_range_vector (value, &value->optimized_out);
424 /* Insert into the vector pointed to by VECTORP the bit range starting of
425 OFFSET bits, and extending for the next LENGTH bits. */
428 insert_into_bit_range_vector (VEC(range_s) **vectorp,
429 LONGEST offset, LONGEST length)
434 /* Insert the range sorted. If there's overlap or the new range
435 would be contiguous with an existing range, merge. */
437 newr.offset = offset;
438 newr.length = length;
440 /* Do a binary search for the position the given range would be
441 inserted if we only considered the starting OFFSET of ranges.
442 Call that position I. Since we also have LENGTH to care for
443 (this is a range afterall), we need to check if the _previous_
444 range overlaps the I range. E.g., calling R the new range:
446 #1 - overlaps with previous
450 |---| |---| |------| ... |--|
455 In the case #1 above, the binary search would return `I=1',
456 meaning, this OFFSET should be inserted at position 1, and the
457 current position 1 should be pushed further (and become 2). But,
458 note that `0' overlaps with R, so we want to merge them.
460 A similar consideration needs to be taken if the new range would
461 be contiguous with the previous range:
463 #2 - contiguous with previous
467 |--| |---| |------| ... |--|
472 If there's no overlap with the previous range, as in:
474 #3 - not overlapping and not contiguous
478 |--| |---| |------| ... |--|
485 #4 - R is the range with lowest offset
489 |--| |---| |------| ... |--|
494 ... we just push the new range to I.
496 All the 4 cases above need to consider that the new range may
497 also overlap several of the ranges that follow, or that R may be
498 contiguous with the following range, and merge. E.g.,
500 #5 - overlapping following ranges
503 |------------------------|
504 |--| |---| |------| ... |--|
513 |--| |---| |------| ... |--|
520 i = VEC_lower_bound (range_s, *vectorp, &newr, range_lessthan);
523 struct range *bef = VEC_index (range_s, *vectorp, i - 1);
525 if (ranges_overlap (bef->offset, bef->length, offset, length))
528 ULONGEST l = std::min (bef->offset, offset);
529 ULONGEST h = std::max (bef->offset + bef->length, offset + length);
535 else if (offset == bef->offset + bef->length)
538 bef->length += length;
544 VEC_safe_insert (range_s, *vectorp, i, &newr);
550 VEC_safe_insert (range_s, *vectorp, i, &newr);
553 /* Check whether the ranges following the one we've just added or
554 touched can be folded in (#5 above). */
555 if (i + 1 < VEC_length (range_s, *vectorp))
562 /* Get the range we just touched. */
563 t = VEC_index (range_s, *vectorp, i);
567 for (; VEC_iterate (range_s, *vectorp, i, r); i++)
568 if (r->offset <= t->offset + t->length)
572 l = std::min (t->offset, r->offset);
573 h = std::max (t->offset + t->length, r->offset + r->length);
582 /* If we couldn't merge this one, we won't be able to
583 merge following ones either, since the ranges are
584 always sorted by OFFSET. */
589 VEC_block_remove (range_s, *vectorp, next, removed);
594 mark_value_bits_unavailable (struct value *value,
595 LONGEST offset, LONGEST length)
597 insert_into_bit_range_vector (&value->unavailable, offset, length);
601 mark_value_bytes_unavailable (struct value *value,
602 LONGEST offset, LONGEST length)
604 mark_value_bits_unavailable (value,
605 offset * TARGET_CHAR_BIT,
606 length * TARGET_CHAR_BIT);
609 /* Find the first range in RANGES that overlaps the range defined by
610 OFFSET and LENGTH, starting at element POS in the RANGES vector,
611 Returns the index into RANGES where such overlapping range was
612 found, or -1 if none was found. */
615 find_first_range_overlap (VEC(range_s) *ranges, int pos,
616 LONGEST offset, LONGEST length)
621 for (i = pos; VEC_iterate (range_s, ranges, i, r); i++)
622 if (ranges_overlap (r->offset, r->length, offset, length))
628 /* Compare LENGTH_BITS of memory at PTR1 + OFFSET1_BITS with the memory at
629 PTR2 + OFFSET2_BITS. Return 0 if the memory is the same, otherwise
632 It must always be the case that:
633 OFFSET1_BITS % TARGET_CHAR_BIT == OFFSET2_BITS % TARGET_CHAR_BIT
635 It is assumed that memory can be accessed from:
636 PTR + (OFFSET_BITS / TARGET_CHAR_BIT)
638 PTR + ((OFFSET_BITS + LENGTH_BITS + TARGET_CHAR_BIT - 1)
639 / TARGET_CHAR_BIT) */
641 memcmp_with_bit_offsets (const gdb_byte *ptr1, size_t offset1_bits,
642 const gdb_byte *ptr2, size_t offset2_bits,
645 gdb_assert (offset1_bits % TARGET_CHAR_BIT
646 == offset2_bits % TARGET_CHAR_BIT);
648 if (offset1_bits % TARGET_CHAR_BIT != 0)
651 gdb_byte mask, b1, b2;
653 /* The offset from the base pointers PTR1 and PTR2 is not a complete
654 number of bytes. A number of bits up to either the next exact
655 byte boundary, or LENGTH_BITS (which ever is sooner) will be
657 bits = TARGET_CHAR_BIT - offset1_bits % TARGET_CHAR_BIT;
658 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
659 mask = (1 << bits) - 1;
661 if (length_bits < bits)
663 mask &= ~(gdb_byte) ((1 << (bits - length_bits)) - 1);
667 /* Now load the two bytes and mask off the bits we care about. */
668 b1 = *(ptr1 + offset1_bits / TARGET_CHAR_BIT) & mask;
669 b2 = *(ptr2 + offset2_bits / TARGET_CHAR_BIT) & mask;
674 /* Now update the length and offsets to take account of the bits
675 we've just compared. */
677 offset1_bits += bits;
678 offset2_bits += bits;
681 if (length_bits % TARGET_CHAR_BIT != 0)
685 gdb_byte mask, b1, b2;
687 /* The length is not an exact number of bytes. After the previous
688 IF.. block then the offsets are byte aligned, or the
689 length is zero (in which case this code is not reached). Compare
690 a number of bits at the end of the region, starting from an exact
692 bits = length_bits % TARGET_CHAR_BIT;
693 o1 = offset1_bits + length_bits - bits;
694 o2 = offset2_bits + length_bits - bits;
696 gdb_assert (bits < sizeof (mask) * TARGET_CHAR_BIT);
697 mask = ((1 << bits) - 1) << (TARGET_CHAR_BIT - bits);
699 gdb_assert (o1 % TARGET_CHAR_BIT == 0);
700 gdb_assert (o2 % TARGET_CHAR_BIT == 0);
702 b1 = *(ptr1 + o1 / TARGET_CHAR_BIT) & mask;
703 b2 = *(ptr2 + o2 / TARGET_CHAR_BIT) & mask;
713 /* We've now taken care of any stray "bits" at the start, or end of
714 the region to compare, the remainder can be covered with a simple
716 gdb_assert (offset1_bits % TARGET_CHAR_BIT == 0);
717 gdb_assert (offset2_bits % TARGET_CHAR_BIT == 0);
718 gdb_assert (length_bits % TARGET_CHAR_BIT == 0);
720 return memcmp (ptr1 + offset1_bits / TARGET_CHAR_BIT,
721 ptr2 + offset2_bits / TARGET_CHAR_BIT,
722 length_bits / TARGET_CHAR_BIT);
725 /* Length is zero, regions match. */
729 /* Helper struct for find_first_range_overlap_and_match and
730 value_contents_bits_eq. Keep track of which slot of a given ranges
731 vector have we last looked at. */
733 struct ranges_and_idx
736 VEC(range_s) *ranges;
738 /* The range we've last found in RANGES. Given ranges are sorted,
739 we can start the next lookup here. */
743 /* Helper function for value_contents_bits_eq. Compare LENGTH bits of
744 RP1's ranges starting at OFFSET1 bits with LENGTH bits of RP2's
745 ranges starting at OFFSET2 bits. Return true if the ranges match
746 and fill in *L and *H with the overlapping window relative to
747 (both) OFFSET1 or OFFSET2. */
750 find_first_range_overlap_and_match (struct ranges_and_idx *rp1,
751 struct ranges_and_idx *rp2,
752 LONGEST offset1, LONGEST offset2,
753 LONGEST length, ULONGEST *l, ULONGEST *h)
755 rp1->idx = find_first_range_overlap (rp1->ranges, rp1->idx,
757 rp2->idx = find_first_range_overlap (rp2->ranges, rp2->idx,
760 if (rp1->idx == -1 && rp2->idx == -1)
766 else if (rp1->idx == -1 || rp2->idx == -1)
774 r1 = VEC_index (range_s, rp1->ranges, rp1->idx);
775 r2 = VEC_index (range_s, rp2->ranges, rp2->idx);
777 /* Get the unavailable windows intersected by the incoming
778 ranges. The first and last ranges that overlap the argument
779 range may be wider than said incoming arguments ranges. */
780 l1 = std::max (offset1, r1->offset);
781 h1 = std::min (offset1 + length, r1->offset + r1->length);
783 l2 = std::max (offset2, r2->offset);
784 h2 = std::min (offset2 + length, offset2 + r2->length);
786 /* Make them relative to the respective start offsets, so we can
787 compare them for equality. */
794 /* Different ranges, no match. */
795 if (l1 != l2 || h1 != h2)
804 /* Helper function for value_contents_eq. The only difference is that
805 this function is bit rather than byte based.
807 Compare LENGTH bits of VAL1's contents starting at OFFSET1 bits
808 with LENGTH bits of VAL2's contents starting at OFFSET2 bits.
809 Return true if the available bits match. */
812 value_contents_bits_eq (const struct value *val1, int offset1,
813 const struct value *val2, int offset2,
816 /* Each array element corresponds to a ranges source (unavailable,
817 optimized out). '1' is for VAL1, '2' for VAL2. */
818 struct ranges_and_idx rp1[2], rp2[2];
820 /* See function description in value.h. */
821 gdb_assert (!val1->lazy && !val2->lazy);
823 /* We shouldn't be trying to compare past the end of the values. */
824 gdb_assert (offset1 + length
825 <= TYPE_LENGTH (val1->enclosing_type) * TARGET_CHAR_BIT);
826 gdb_assert (offset2 + length
827 <= TYPE_LENGTH (val2->enclosing_type) * TARGET_CHAR_BIT);
829 memset (&rp1, 0, sizeof (rp1));
830 memset (&rp2, 0, sizeof (rp2));
831 rp1[0].ranges = val1->unavailable;
832 rp2[0].ranges = val2->unavailable;
833 rp1[1].ranges = val1->optimized_out;
834 rp2[1].ranges = val2->optimized_out;
838 ULONGEST l = 0, h = 0; /* init for gcc -Wall */
841 for (i = 0; i < 2; i++)
843 ULONGEST l_tmp, h_tmp;
845 /* The contents only match equal if the invalid/unavailable
846 contents ranges match as well. */
847 if (!find_first_range_overlap_and_match (&rp1[i], &rp2[i],
848 offset1, offset2, length,
852 /* We're interested in the lowest/first range found. */
853 if (i == 0 || l_tmp < l)
860 /* Compare the available/valid contents. */
861 if (memcmp_with_bit_offsets (val1->contents, offset1,
862 val2->contents, offset2, l) != 0)
874 value_contents_eq (const struct value *val1, LONGEST offset1,
875 const struct value *val2, LONGEST offset2,
878 return value_contents_bits_eq (val1, offset1 * TARGET_CHAR_BIT,
879 val2, offset2 * TARGET_CHAR_BIT,
880 length * TARGET_CHAR_BIT);
883 /* Prototypes for local functions. */
885 static void show_values (char *, int);
888 /* The value-history records all the values printed
889 by print commands during this session. Each chunk
890 records 60 consecutive values. The first chunk on
891 the chain records the most recent values.
892 The total number of values is in value_history_count. */
894 #define VALUE_HISTORY_CHUNK 60
896 struct value_history_chunk
898 struct value_history_chunk *next;
899 struct value *values[VALUE_HISTORY_CHUNK];
902 /* Chain of chunks now in use. */
904 static struct value_history_chunk *value_history_chain;
906 static int value_history_count; /* Abs number of last entry stored. */
909 /* List of all value objects currently allocated
910 (except for those released by calls to release_value)
911 This is so they can be freed after each command. */
913 static struct value *all_values;
915 /* Allocate a lazy value for type TYPE. Its actual content is
916 "lazily" allocated too: the content field of the return value is
917 NULL; it will be allocated when it is fetched from the target. */
920 allocate_value_lazy (struct type *type)
924 /* Call check_typedef on our type to make sure that, if TYPE
925 is a TYPE_CODE_TYPEDEF, its length is set to the length
926 of the target type instead of zero. However, we do not
927 replace the typedef type by the target type, because we want
928 to keep the typedef in order to be able to set the VAL's type
929 description correctly. */
930 check_typedef (type);
932 val = XCNEW (struct value);
933 val->contents = NULL;
934 val->next = all_values;
937 val->enclosing_type = type;
938 VALUE_LVAL (val) = not_lval;
939 val->location.address = 0;
944 val->embedded_offset = 0;
945 val->pointed_to_offset = 0;
947 val->initialized = 1; /* Default to initialized. */
949 /* Values start out on the all_values chain. */
950 val->reference_count = 1;
955 /* The maximum size, in bytes, that GDB will try to allocate for a value.
956 The initial value of 64k was not selected for any specific reason, it is
957 just a reasonable starting point. */
959 static int max_value_size = 65536; /* 64k bytes */
961 /* It is critical that the MAX_VALUE_SIZE is at least as big as the size of
962 LONGEST, otherwise GDB will not be able to parse integer values from the
963 CLI; for example if the MAX_VALUE_SIZE could be set to 1 then GDB would
964 be unable to parse "set max-value-size 2".
966 As we want a consistent GDB experience across hosts with different sizes
967 of LONGEST, this arbitrary minimum value was selected, so long as this
968 is bigger than LONGEST on all GDB supported hosts we're fine. */
970 #define MIN_VALUE_FOR_MAX_VALUE_SIZE 16
971 gdb_static_assert (sizeof (LONGEST) <= MIN_VALUE_FOR_MAX_VALUE_SIZE);
973 /* Implement the "set max-value-size" command. */
976 set_max_value_size (char *args, int from_tty,
977 struct cmd_list_element *c)
979 gdb_assert (max_value_size == -1 || max_value_size >= 0);
981 if (max_value_size > -1 && max_value_size < MIN_VALUE_FOR_MAX_VALUE_SIZE)
983 max_value_size = MIN_VALUE_FOR_MAX_VALUE_SIZE;
984 error (_("max-value-size set too low, increasing to %d bytes"),
989 /* Implement the "show max-value-size" command. */
992 show_max_value_size (struct ui_file *file, int from_tty,
993 struct cmd_list_element *c, const char *value)
995 if (max_value_size == -1)
996 fprintf_filtered (file, _("Maximum value size is unlimited.\n"));
998 fprintf_filtered (file, _("Maximum value size is %d bytes.\n"),
1002 /* Called before we attempt to allocate or reallocate a buffer for the
1003 contents of a value. TYPE is the type of the value for which we are
1004 allocating the buffer. If the buffer is too large (based on the user
1005 controllable setting) then throw an error. If this function returns
1006 then we should attempt to allocate the buffer. */
1009 check_type_length_before_alloc (const struct type *type)
1011 unsigned int length = TYPE_LENGTH (type);
1013 if (max_value_size > -1 && length > max_value_size)
1015 if (TYPE_NAME (type) != NULL)
1016 error (_("value of type `%s' requires %u bytes, which is more "
1017 "than max-value-size"), TYPE_NAME (type), length);
1019 error (_("value requires %u bytes, which is more than "
1020 "max-value-size"), length);
1024 /* Allocate the contents of VAL if it has not been allocated yet. */
1027 allocate_value_contents (struct value *val)
1031 check_type_length_before_alloc (val->enclosing_type);
1033 = (gdb_byte *) xzalloc (TYPE_LENGTH (val->enclosing_type));
1037 /* Allocate a value and its contents for type TYPE. */
1040 allocate_value (struct type *type)
1042 struct value *val = allocate_value_lazy (type);
1044 allocate_value_contents (val);
1049 /* Allocate a value that has the correct length
1050 for COUNT repetitions of type TYPE. */
1053 allocate_repeat_value (struct type *type, int count)
1055 int low_bound = current_language->string_lower_bound; /* ??? */
1056 /* FIXME-type-allocation: need a way to free this type when we are
1058 struct type *array_type
1059 = lookup_array_range_type (type, low_bound, count + low_bound - 1);
1061 return allocate_value (array_type);
1065 allocate_computed_value (struct type *type,
1066 const struct lval_funcs *funcs,
1069 struct value *v = allocate_value_lazy (type);
1071 VALUE_LVAL (v) = lval_computed;
1072 v->location.computed.funcs = funcs;
1073 v->location.computed.closure = closure;
1078 /* Allocate NOT_LVAL value for type TYPE being OPTIMIZED_OUT. */
1081 allocate_optimized_out_value (struct type *type)
1083 struct value *retval = allocate_value_lazy (type);
1085 mark_value_bytes_optimized_out (retval, 0, TYPE_LENGTH (type));
1086 set_value_lazy (retval, 0);
1090 /* Accessor methods. */
1093 value_next (const struct value *value)
1099 value_type (const struct value *value)
1104 deprecated_set_value_type (struct value *value, struct type *type)
1110 value_offset (const struct value *value)
1112 return value->offset;
1115 set_value_offset (struct value *value, LONGEST offset)
1117 value->offset = offset;
1121 value_bitpos (const struct value *value)
1123 return value->bitpos;
1126 set_value_bitpos (struct value *value, LONGEST bit)
1128 value->bitpos = bit;
1132 value_bitsize (const struct value *value)
1134 return value->bitsize;
1137 set_value_bitsize (struct value *value, LONGEST bit)
1139 value->bitsize = bit;
1143 value_parent (const struct value *value)
1145 return value->parent;
1151 set_value_parent (struct value *value, struct value *parent)
1153 struct value *old = value->parent;
1155 value->parent = parent;
1157 value_incref (parent);
1162 value_contents_raw (struct value *value)
1164 struct gdbarch *arch = get_value_arch (value);
1165 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1167 allocate_value_contents (value);
1168 return value->contents + value->embedded_offset * unit_size;
1172 value_contents_all_raw (struct value *value)
1174 allocate_value_contents (value);
1175 return value->contents;
1179 value_enclosing_type (const struct value *value)
1181 return value->enclosing_type;
1184 /* Look at value.h for description. */
1187 value_actual_type (struct value *value, int resolve_simple_types,
1188 int *real_type_found)
1190 struct value_print_options opts;
1191 struct type *result;
1193 get_user_print_options (&opts);
1195 if (real_type_found)
1196 *real_type_found = 0;
1197 result = value_type (value);
1198 if (opts.objectprint)
1200 /* If result's target type is TYPE_CODE_STRUCT, proceed to
1201 fetch its rtti type. */
1202 if ((TYPE_CODE (result) == TYPE_CODE_PTR || TYPE_IS_REFERENCE (result))
1203 && TYPE_CODE (check_typedef (TYPE_TARGET_TYPE (result)))
1205 && !value_optimized_out (value))
1207 struct type *real_type;
1209 real_type = value_rtti_indirect_type (value, NULL, NULL, NULL);
1212 if (real_type_found)
1213 *real_type_found = 1;
1217 else if (resolve_simple_types)
1219 if (real_type_found)
1220 *real_type_found = 1;
1221 result = value_enclosing_type (value);
1229 error_value_optimized_out (void)
1231 error (_("value has been optimized out"));
1235 require_not_optimized_out (const struct value *value)
1237 if (!VEC_empty (range_s, value->optimized_out))
1239 if (value->lval == lval_register)
1240 error (_("register has not been saved in frame"));
1242 error_value_optimized_out ();
1247 require_available (const struct value *value)
1249 if (!VEC_empty (range_s, value->unavailable))
1250 throw_error (NOT_AVAILABLE_ERROR, _("value is not available"));
1254 value_contents_for_printing (struct value *value)
1257 value_fetch_lazy (value);
1258 return value->contents;
1262 value_contents_for_printing_const (const struct value *value)
1264 gdb_assert (!value->lazy);
1265 return value->contents;
1269 value_contents_all (struct value *value)
1271 const gdb_byte *result = value_contents_for_printing (value);
1272 require_not_optimized_out (value);
1273 require_available (value);
1277 /* Copy ranges in SRC_RANGE that overlap [SRC_BIT_OFFSET,
1278 SRC_BIT_OFFSET+BIT_LENGTH) ranges into *DST_RANGE, adjusted. */
1281 ranges_copy_adjusted (VEC (range_s) **dst_range, int dst_bit_offset,
1282 VEC (range_s) *src_range, int src_bit_offset,
1288 for (i = 0; VEC_iterate (range_s, src_range, i, r); i++)
1292 l = std::max (r->offset, (LONGEST) src_bit_offset);
1293 h = std::min (r->offset + r->length,
1294 (LONGEST) src_bit_offset + bit_length);
1297 insert_into_bit_range_vector (dst_range,
1298 dst_bit_offset + (l - src_bit_offset),
1303 /* Copy the ranges metadata in SRC that overlaps [SRC_BIT_OFFSET,
1304 SRC_BIT_OFFSET+BIT_LENGTH) into DST, adjusted. */
1307 value_ranges_copy_adjusted (struct value *dst, int dst_bit_offset,
1308 const struct value *src, int src_bit_offset,
1311 ranges_copy_adjusted (&dst->unavailable, dst_bit_offset,
1312 src->unavailable, src_bit_offset,
1314 ranges_copy_adjusted (&dst->optimized_out, dst_bit_offset,
1315 src->optimized_out, src_bit_offset,
1319 /* Copy LENGTH target addressable memory units of SRC value's (all) contents
1320 (value_contents_all) starting at SRC_OFFSET, into DST value's (all)
1321 contents, starting at DST_OFFSET. If unavailable contents are
1322 being copied from SRC, the corresponding DST contents are marked
1323 unavailable accordingly. Neither DST nor SRC may be lazy
1326 It is assumed the contents of DST in the [DST_OFFSET,
1327 DST_OFFSET+LENGTH) range are wholly available. */
1330 value_contents_copy_raw (struct value *dst, LONGEST dst_offset,
1331 struct value *src, LONGEST src_offset, LONGEST length)
1333 LONGEST src_bit_offset, dst_bit_offset, bit_length;
1334 struct gdbarch *arch = get_value_arch (src);
1335 int unit_size = gdbarch_addressable_memory_unit_size (arch);
1337 /* A lazy DST would make that this copy operation useless, since as
1338 soon as DST's contents were un-lazied (by a later value_contents
1339 call, say), the contents would be overwritten. A lazy SRC would
1340 mean we'd be copying garbage. */
1341 gdb_assert (!dst->lazy && !src->lazy);
1343 /* The overwritten DST range gets unavailability ORed in, not
1344 replaced. Make sure to remember to implement replacing if it
1345 turns out actually necessary. */
1346 gdb_assert (value_bytes_available (dst, dst_offset, length));
1347 gdb_assert (!value_bits_any_optimized_out (dst,
1348 TARGET_CHAR_BIT * dst_offset,
1349 TARGET_CHAR_BIT * length));
1351 /* Copy the data. */
1352 memcpy (value_contents_all_raw (dst) + dst_offset * unit_size,
1353 value_contents_all_raw (src) + src_offset * unit_size,
1354 length * unit_size);
1356 /* Copy the meta-data, adjusted. */
1357 src_bit_offset = src_offset * unit_size * HOST_CHAR_BIT;
1358 dst_bit_offset = dst_offset * unit_size * HOST_CHAR_BIT;
1359 bit_length = length * unit_size * HOST_CHAR_BIT;
1361 value_ranges_copy_adjusted (dst, dst_bit_offset,
1362 src, src_bit_offset,
1366 /* Copy LENGTH bytes of SRC value's (all) contents
1367 (value_contents_all) starting at SRC_OFFSET byte, into DST value's
1368 (all) contents, starting at DST_OFFSET. If unavailable contents
1369 are being copied from SRC, the corresponding DST contents are
1370 marked unavailable accordingly. DST must not be lazy. If SRC is
1371 lazy, it will be fetched now.
1373 It is assumed the contents of DST in the [DST_OFFSET,
1374 DST_OFFSET+LENGTH) range are wholly available. */
1377 value_contents_copy (struct value *dst, LONGEST dst_offset,
1378 struct value *src, LONGEST src_offset, LONGEST length)
1381 value_fetch_lazy (src);
1383 value_contents_copy_raw (dst, dst_offset, src, src_offset, length);
1387 value_lazy (const struct value *value)
1393 set_value_lazy (struct value *value, int val)
1399 value_stack (const struct value *value)
1401 return value->stack;
1405 set_value_stack (struct value *value, int val)
1411 value_contents (struct value *value)
1413 const gdb_byte *result = value_contents_writeable (value);
1414 require_not_optimized_out (value);
1415 require_available (value);
1420 value_contents_writeable (struct value *value)
1423 value_fetch_lazy (value);
1424 return value_contents_raw (value);
1428 value_optimized_out (struct value *value)
1430 /* We can only know if a value is optimized out once we have tried to
1432 if (VEC_empty (range_s, value->optimized_out) && value->lazy)
1436 value_fetch_lazy (value);
1438 CATCH (ex, RETURN_MASK_ERROR)
1440 /* Fall back to checking value->optimized_out. */
1445 return !VEC_empty (range_s, value->optimized_out);
1448 /* Mark contents of VALUE as optimized out, starting at OFFSET bytes, and
1449 the following LENGTH bytes. */
1452 mark_value_bytes_optimized_out (struct value *value, int offset, int length)
1454 mark_value_bits_optimized_out (value,
1455 offset * TARGET_CHAR_BIT,
1456 length * TARGET_CHAR_BIT);
1462 mark_value_bits_optimized_out (struct value *value,
1463 LONGEST offset, LONGEST length)
1465 insert_into_bit_range_vector (&value->optimized_out, offset, length);
1469 value_bits_synthetic_pointer (const struct value *value,
1470 LONGEST offset, LONGEST length)
1472 if (value->lval != lval_computed
1473 || !value->location.computed.funcs->check_synthetic_pointer)
1475 return value->location.computed.funcs->check_synthetic_pointer (value,
1481 value_embedded_offset (const struct value *value)
1483 return value->embedded_offset;
1487 set_value_embedded_offset (struct value *value, LONGEST val)
1489 value->embedded_offset = val;
1493 value_pointed_to_offset (const struct value *value)
1495 return value->pointed_to_offset;
1499 set_value_pointed_to_offset (struct value *value, LONGEST val)
1501 value->pointed_to_offset = val;
1504 const struct lval_funcs *
1505 value_computed_funcs (const struct value *v)
1507 gdb_assert (value_lval_const (v) == lval_computed);
1509 return v->location.computed.funcs;
1513 value_computed_closure (const struct value *v)
1515 gdb_assert (v->lval == lval_computed);
1517 return v->location.computed.closure;
1521 deprecated_value_lval_hack (struct value *value)
1523 return &value->lval;
1527 value_lval_const (const struct value *value)
1533 value_address (const struct value *value)
1535 if (value->lval != lval_memory)
1537 if (value->parent != NULL)
1538 return value_address (value->parent) + value->offset;
1539 if (NULL != TYPE_DATA_LOCATION (value_type (value)))
1541 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (value_type (value)));
1542 return TYPE_DATA_LOCATION_ADDR (value_type (value));
1545 return value->location.address + value->offset;
1549 value_raw_address (const struct value *value)
1551 if (value->lval != lval_memory)
1553 return value->location.address;
1557 set_value_address (struct value *value, CORE_ADDR addr)
1559 gdb_assert (value->lval == lval_memory);
1560 value->location.address = addr;
1563 struct internalvar **
1564 deprecated_value_internalvar_hack (struct value *value)
1566 return &value->location.internalvar;
1570 deprecated_value_next_frame_id_hack (struct value *value)
1572 gdb_assert (value->lval == lval_register);
1573 return &value->location.reg.next_frame_id;
1577 deprecated_value_regnum_hack (struct value *value)
1579 gdb_assert (value->lval == lval_register);
1580 return &value->location.reg.regnum;
1584 deprecated_value_modifiable (const struct value *value)
1586 return value->modifiable;
1589 /* Return a mark in the value chain. All values allocated after the
1590 mark is obtained (except for those released) are subject to being freed
1591 if a subsequent value_free_to_mark is passed the mark. */
1598 /* Take a reference to VAL. VAL will not be deallocated until all
1599 references are released. */
1602 value_incref (struct value *val)
1604 val->reference_count++;
1607 /* Release a reference to VAL, which was acquired with value_incref.
1608 This function is also called to deallocate values from the value
1612 value_free (struct value *val)
1616 gdb_assert (val->reference_count > 0);
1617 val->reference_count--;
1618 if (val->reference_count > 0)
1621 /* If there's an associated parent value, drop our reference to
1623 if (val->parent != NULL)
1624 value_free (val->parent);
1626 if (VALUE_LVAL (val) == lval_computed)
1628 const struct lval_funcs *funcs = val->location.computed.funcs;
1630 if (funcs->free_closure)
1631 funcs->free_closure (val);
1633 else if (VALUE_LVAL (val) == lval_xcallable)
1634 free_xmethod_worker (val->location.xm_worker);
1636 xfree (val->contents);
1637 VEC_free (range_s, val->unavailable);
1642 /* Free all values allocated since MARK was obtained by value_mark
1643 (except for those released). */
1645 value_free_to_mark (const struct value *mark)
1650 for (val = all_values; val && val != mark; val = next)
1659 /* Free all the values that have been allocated (except for those released).
1660 Call after each command, successful or not.
1661 In practice this is called before each command, which is sufficient. */
1664 free_all_values (void)
1669 for (val = all_values; val; val = next)
1679 /* Frees all the elements in a chain of values. */
1682 free_value_chain (struct value *v)
1688 next = value_next (v);
1693 /* Remove VAL from the chain all_values
1694 so it will not be freed automatically. */
1697 release_value (struct value *val)
1701 if (all_values == val)
1703 all_values = val->next;
1709 for (v = all_values; v; v = v->next)
1713 v->next = val->next;
1721 /* If the value is not already released, release it.
1722 If the value is already released, increment its reference count.
1723 That is, this function ensures that the value is released from the
1724 value chain and that the caller owns a reference to it. */
1727 release_value_or_incref (struct value *val)
1732 release_value (val);
1735 /* Release all values up to mark */
1737 value_release_to_mark (const struct value *mark)
1742 for (val = next = all_values; next; next = next->next)
1744 if (next->next == mark)
1746 all_values = next->next;
1756 /* Return a copy of the value ARG.
1757 It contains the same contents, for same memory address,
1758 but it's a different block of storage. */
1761 value_copy (struct value *arg)
1763 struct type *encl_type = value_enclosing_type (arg);
1766 if (value_lazy (arg))
1767 val = allocate_value_lazy (encl_type);
1769 val = allocate_value (encl_type);
1770 val->type = arg->type;
1771 VALUE_LVAL (val) = VALUE_LVAL (arg);
1772 val->location = arg->location;
1773 val->offset = arg->offset;
1774 val->bitpos = arg->bitpos;
1775 val->bitsize = arg->bitsize;
1776 val->lazy = arg->lazy;
1777 val->embedded_offset = value_embedded_offset (arg);
1778 val->pointed_to_offset = arg->pointed_to_offset;
1779 val->modifiable = arg->modifiable;
1780 if (!value_lazy (val))
1782 memcpy (value_contents_all_raw (val), value_contents_all_raw (arg),
1783 TYPE_LENGTH (value_enclosing_type (arg)));
1786 val->unavailable = VEC_copy (range_s, arg->unavailable);
1787 val->optimized_out = VEC_copy (range_s, arg->optimized_out);
1788 set_value_parent (val, arg->parent);
1789 if (VALUE_LVAL (val) == lval_computed)
1791 const struct lval_funcs *funcs = val->location.computed.funcs;
1793 if (funcs->copy_closure)
1794 val->location.computed.closure = funcs->copy_closure (val);
1799 /* Return a "const" and/or "volatile" qualified version of the value V.
1800 If CNST is true, then the returned value will be qualified with
1802 if VOLTL is true, then the returned value will be qualified with
1806 make_cv_value (int cnst, int voltl, struct value *v)
1808 struct type *val_type = value_type (v);
1809 struct type *enclosing_type = value_enclosing_type (v);
1810 struct value *cv_val = value_copy (v);
1812 deprecated_set_value_type (cv_val,
1813 make_cv_type (cnst, voltl, val_type, NULL));
1814 set_value_enclosing_type (cv_val,
1815 make_cv_type (cnst, voltl, enclosing_type, NULL));
1820 /* Return a version of ARG that is non-lvalue. */
1823 value_non_lval (struct value *arg)
1825 if (VALUE_LVAL (arg) != not_lval)
1827 struct type *enc_type = value_enclosing_type (arg);
1828 struct value *val = allocate_value (enc_type);
1830 memcpy (value_contents_all_raw (val), value_contents_all (arg),
1831 TYPE_LENGTH (enc_type));
1832 val->type = arg->type;
1833 set_value_embedded_offset (val, value_embedded_offset (arg));
1834 set_value_pointed_to_offset (val, value_pointed_to_offset (arg));
1840 /* Write contents of V at ADDR and set its lval type to be LVAL_MEMORY. */
1843 value_force_lval (struct value *v, CORE_ADDR addr)
1845 gdb_assert (VALUE_LVAL (v) == not_lval);
1847 write_memory (addr, value_contents_raw (v), TYPE_LENGTH (value_type (v)));
1848 v->lval = lval_memory;
1849 v->location.address = addr;
1853 set_value_component_location (struct value *component,
1854 const struct value *whole)
1858 gdb_assert (whole->lval != lval_xcallable);
1860 if (whole->lval == lval_internalvar)
1861 VALUE_LVAL (component) = lval_internalvar_component;
1863 VALUE_LVAL (component) = whole->lval;
1865 component->location = whole->location;
1866 if (whole->lval == lval_computed)
1868 const struct lval_funcs *funcs = whole->location.computed.funcs;
1870 if (funcs->copy_closure)
1871 component->location.computed.closure = funcs->copy_closure (whole);
1874 /* If type has a dynamic resolved location property
1875 update it's value address. */
1876 type = value_type (whole);
1877 if (NULL != TYPE_DATA_LOCATION (type)
1878 && TYPE_DATA_LOCATION_KIND (type) == PROP_CONST)
1879 set_value_address (component, TYPE_DATA_LOCATION_ADDR (type));
1882 /* Access to the value history. */
1884 /* Record a new value in the value history.
1885 Returns the absolute history index of the entry. */
1888 record_latest_value (struct value *val)
1892 /* We don't want this value to have anything to do with the inferior anymore.
1893 In particular, "set $1 = 50" should not affect the variable from which
1894 the value was taken, and fast watchpoints should be able to assume that
1895 a value on the value history never changes. */
1896 if (value_lazy (val))
1897 value_fetch_lazy (val);
1898 /* We preserve VALUE_LVAL so that the user can find out where it was fetched
1899 from. This is a bit dubious, because then *&$1 does not just return $1
1900 but the current contents of that location. c'est la vie... */
1901 val->modifiable = 0;
1903 /* The value may have already been released, in which case we're adding a
1904 new reference for its entry in the history. That is why we call
1905 release_value_or_incref here instead of release_value. */
1906 release_value_or_incref (val);
1908 /* Here we treat value_history_count as origin-zero
1909 and applying to the value being stored now. */
1911 i = value_history_count % VALUE_HISTORY_CHUNK;
1914 struct value_history_chunk *newobj = XCNEW (struct value_history_chunk);
1916 newobj->next = value_history_chain;
1917 value_history_chain = newobj;
1920 value_history_chain->values[i] = val;
1922 /* Now we regard value_history_count as origin-one
1923 and applying to the value just stored. */
1925 return ++value_history_count;
1928 /* Return a copy of the value in the history with sequence number NUM. */
1931 access_value_history (int num)
1933 struct value_history_chunk *chunk;
1938 absnum += value_history_count;
1943 error (_("The history is empty."));
1945 error (_("There is only one value in the history."));
1947 error (_("History does not go back to $$%d."), -num);
1949 if (absnum > value_history_count)
1950 error (_("History has not yet reached $%d."), absnum);
1954 /* Now absnum is always absolute and origin zero. */
1956 chunk = value_history_chain;
1957 for (i = (value_history_count - 1) / VALUE_HISTORY_CHUNK
1958 - absnum / VALUE_HISTORY_CHUNK;
1960 chunk = chunk->next;
1962 return value_copy (chunk->values[absnum % VALUE_HISTORY_CHUNK]);
1966 show_values (char *num_exp, int from_tty)
1974 /* "show values +" should print from the stored position.
1975 "show values <exp>" should print around value number <exp>. */
1976 if (num_exp[0] != '+' || num_exp[1] != '\0')
1977 num = parse_and_eval_long (num_exp) - 5;
1981 /* "show values" means print the last 10 values. */
1982 num = value_history_count - 9;
1988 for (i = num; i < num + 10 && i <= value_history_count; i++)
1990 struct value_print_options opts;
1992 val = access_value_history (i);
1993 printf_filtered (("$%d = "), i);
1994 get_user_print_options (&opts);
1995 value_print (val, gdb_stdout, &opts);
1996 printf_filtered (("\n"));
1999 /* The next "show values +" should start after what we just printed. */
2002 /* Hitting just return after this command should do the same thing as
2003 "show values +". If num_exp is null, this is unnecessary, since
2004 "show values +" is not useful after "show values". */
2005 if (from_tty && num_exp)
2006 set_repeat_arguments ("+");
2009 enum internalvar_kind
2011 /* The internal variable is empty. */
2014 /* The value of the internal variable is provided directly as
2015 a GDB value object. */
2018 /* A fresh value is computed via a call-back routine on every
2019 access to the internal variable. */
2020 INTERNALVAR_MAKE_VALUE,
2022 /* The internal variable holds a GDB internal convenience function. */
2023 INTERNALVAR_FUNCTION,
2025 /* The variable holds an integer value. */
2026 INTERNALVAR_INTEGER,
2028 /* The variable holds a GDB-provided string. */
2032 union internalvar_data
2034 /* A value object used with INTERNALVAR_VALUE. */
2035 struct value *value;
2037 /* The call-back routine used with INTERNALVAR_MAKE_VALUE. */
2040 /* The functions to call. */
2041 const struct internalvar_funcs *functions;
2043 /* The function's user-data. */
2047 /* The internal function used with INTERNALVAR_FUNCTION. */
2050 struct internal_function *function;
2051 /* True if this is the canonical name for the function. */
2055 /* An integer value used with INTERNALVAR_INTEGER. */
2058 /* If type is non-NULL, it will be used as the type to generate
2059 a value for this internal variable. If type is NULL, a default
2060 integer type for the architecture is used. */
2065 /* A string value used with INTERNALVAR_STRING. */
2069 /* Internal variables. These are variables within the debugger
2070 that hold values assigned by debugger commands.
2071 The user refers to them with a '$' prefix
2072 that does not appear in the variable names stored internally. */
2076 struct internalvar *next;
2079 /* We support various different kinds of content of an internal variable.
2080 enum internalvar_kind specifies the kind, and union internalvar_data
2081 provides the data associated with this particular kind. */
2083 enum internalvar_kind kind;
2085 union internalvar_data u;
2088 static struct internalvar *internalvars;
2090 /* If the variable does not already exist create it and give it the
2091 value given. If no value is given then the default is zero. */
2093 init_if_undefined_command (const char* args, int from_tty)
2095 struct internalvar* intvar;
2097 /* Parse the expression - this is taken from set_command(). */
2098 expression_up expr = parse_expression (args);
2100 /* Validate the expression.
2101 Was the expression an assignment?
2102 Or even an expression at all? */
2103 if (expr->nelts == 0 || expr->elts[0].opcode != BINOP_ASSIGN)
2104 error (_("Init-if-undefined requires an assignment expression."));
2106 /* Extract the variable from the parsed expression.
2107 In the case of an assign the lvalue will be in elts[1] and elts[2]. */
2108 if (expr->elts[1].opcode != OP_INTERNALVAR)
2109 error (_("The first parameter to init-if-undefined "
2110 "should be a GDB variable."));
2111 intvar = expr->elts[2].internalvar;
2113 /* Only evaluate the expression if the lvalue is void.
2114 This may still fail if the expresssion is invalid. */
2115 if (intvar->kind == INTERNALVAR_VOID)
2116 evaluate_expression (expr.get ());
2120 /* Look up an internal variable with name NAME. NAME should not
2121 normally include a dollar sign.
2123 If the specified internal variable does not exist,
2124 the return value is NULL. */
2126 struct internalvar *
2127 lookup_only_internalvar (const char *name)
2129 struct internalvar *var;
2131 for (var = internalvars; var; var = var->next)
2132 if (strcmp (var->name, name) == 0)
2138 /* Complete NAME by comparing it to the names of internal
2142 complete_internalvar (completion_tracker &tracker, const char *name)
2144 struct internalvar *var;
2147 len = strlen (name);
2149 for (var = internalvars; var; var = var->next)
2150 if (strncmp (var->name, name, len) == 0)
2152 gdb::unique_xmalloc_ptr<char> copy (xstrdup (var->name));
2154 tracker.add_completion (std::move (copy));
2158 /* Create an internal variable with name NAME and with a void value.
2159 NAME should not normally include a dollar sign. */
2161 struct internalvar *
2162 create_internalvar (const char *name)
2164 struct internalvar *var = XNEW (struct internalvar);
2166 var->name = concat (name, (char *)NULL);
2167 var->kind = INTERNALVAR_VOID;
2168 var->next = internalvars;
2173 /* Create an internal variable with name NAME and register FUN as the
2174 function that value_of_internalvar uses to create a value whenever
2175 this variable is referenced. NAME should not normally include a
2176 dollar sign. DATA is passed uninterpreted to FUN when it is
2177 called. CLEANUP, if not NULL, is called when the internal variable
2178 is destroyed. It is passed DATA as its only argument. */
2180 struct internalvar *
2181 create_internalvar_type_lazy (const char *name,
2182 const struct internalvar_funcs *funcs,
2185 struct internalvar *var = create_internalvar (name);
2187 var->kind = INTERNALVAR_MAKE_VALUE;
2188 var->u.make_value.functions = funcs;
2189 var->u.make_value.data = data;
2193 /* See documentation in value.h. */
2196 compile_internalvar_to_ax (struct internalvar *var,
2197 struct agent_expr *expr,
2198 struct axs_value *value)
2200 if (var->kind != INTERNALVAR_MAKE_VALUE
2201 || var->u.make_value.functions->compile_to_ax == NULL)
2204 var->u.make_value.functions->compile_to_ax (var, expr, value,
2205 var->u.make_value.data);
2209 /* Look up an internal variable with name NAME. NAME should not
2210 normally include a dollar sign.
2212 If the specified internal variable does not exist,
2213 one is created, with a void value. */
2215 struct internalvar *
2216 lookup_internalvar (const char *name)
2218 struct internalvar *var;
2220 var = lookup_only_internalvar (name);
2224 return create_internalvar (name);
2227 /* Return current value of internal variable VAR. For variables that
2228 are not inherently typed, use a value type appropriate for GDBARCH. */
2231 value_of_internalvar (struct gdbarch *gdbarch, struct internalvar *var)
2234 struct trace_state_variable *tsv;
2236 /* If there is a trace state variable of the same name, assume that
2237 is what we really want to see. */
2238 tsv = find_trace_state_variable (var->name);
2241 tsv->value_known = target_get_trace_state_variable_value (tsv->number,
2243 if (tsv->value_known)
2244 val = value_from_longest (builtin_type (gdbarch)->builtin_int64,
2247 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2253 case INTERNALVAR_VOID:
2254 val = allocate_value (builtin_type (gdbarch)->builtin_void);
2257 case INTERNALVAR_FUNCTION:
2258 val = allocate_value (builtin_type (gdbarch)->internal_fn);
2261 case INTERNALVAR_INTEGER:
2262 if (!var->u.integer.type)
2263 val = value_from_longest (builtin_type (gdbarch)->builtin_int,
2264 var->u.integer.val);
2266 val = value_from_longest (var->u.integer.type, var->u.integer.val);
2269 case INTERNALVAR_STRING:
2270 val = value_cstring (var->u.string, strlen (var->u.string),
2271 builtin_type (gdbarch)->builtin_char);
2274 case INTERNALVAR_VALUE:
2275 val = value_copy (var->u.value);
2276 if (value_lazy (val))
2277 value_fetch_lazy (val);
2280 case INTERNALVAR_MAKE_VALUE:
2281 val = (*var->u.make_value.functions->make_value) (gdbarch, var,
2282 var->u.make_value.data);
2286 internal_error (__FILE__, __LINE__, _("bad kind"));
2289 /* Change the VALUE_LVAL to lval_internalvar so that future operations
2290 on this value go back to affect the original internal variable.
2292 Do not do this for INTERNALVAR_MAKE_VALUE variables, as those have
2293 no underlying modifyable state in the internal variable.
2295 Likewise, if the variable's value is a computed lvalue, we want
2296 references to it to produce another computed lvalue, where
2297 references and assignments actually operate through the
2298 computed value's functions.
2300 This means that internal variables with computed values
2301 behave a little differently from other internal variables:
2302 assignments to them don't just replace the previous value
2303 altogether. At the moment, this seems like the behavior we
2306 if (var->kind != INTERNALVAR_MAKE_VALUE
2307 && val->lval != lval_computed)
2309 VALUE_LVAL (val) = lval_internalvar;
2310 VALUE_INTERNALVAR (val) = var;
2317 get_internalvar_integer (struct internalvar *var, LONGEST *result)
2319 if (var->kind == INTERNALVAR_INTEGER)
2321 *result = var->u.integer.val;
2325 if (var->kind == INTERNALVAR_VALUE)
2327 struct type *type = check_typedef (value_type (var->u.value));
2329 if (TYPE_CODE (type) == TYPE_CODE_INT)
2331 *result = value_as_long (var->u.value);
2340 get_internalvar_function (struct internalvar *var,
2341 struct internal_function **result)
2345 case INTERNALVAR_FUNCTION:
2346 *result = var->u.fn.function;
2355 set_internalvar_component (struct internalvar *var,
2356 LONGEST offset, LONGEST bitpos,
2357 LONGEST bitsize, struct value *newval)
2360 struct gdbarch *arch;
2365 case INTERNALVAR_VALUE:
2366 addr = value_contents_writeable (var->u.value);
2367 arch = get_value_arch (var->u.value);
2368 unit_size = gdbarch_addressable_memory_unit_size (arch);
2371 modify_field (value_type (var->u.value), addr + offset,
2372 value_as_long (newval), bitpos, bitsize);
2374 memcpy (addr + offset * unit_size, value_contents (newval),
2375 TYPE_LENGTH (value_type (newval)));
2379 /* We can never get a component of any other kind. */
2380 internal_error (__FILE__, __LINE__, _("set_internalvar_component"));
2385 set_internalvar (struct internalvar *var, struct value *val)
2387 enum internalvar_kind new_kind;
2388 union internalvar_data new_data = { 0 };
2390 if (var->kind == INTERNALVAR_FUNCTION && var->u.fn.canonical)
2391 error (_("Cannot overwrite convenience function %s"), var->name);
2393 /* Prepare new contents. */
2394 switch (TYPE_CODE (check_typedef (value_type (val))))
2396 case TYPE_CODE_VOID:
2397 new_kind = INTERNALVAR_VOID;
2400 case TYPE_CODE_INTERNAL_FUNCTION:
2401 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2402 new_kind = INTERNALVAR_FUNCTION;
2403 get_internalvar_function (VALUE_INTERNALVAR (val),
2404 &new_data.fn.function);
2405 /* Copies created here are never canonical. */
2409 new_kind = INTERNALVAR_VALUE;
2410 new_data.value = value_copy (val);
2411 new_data.value->modifiable = 1;
2413 /* Force the value to be fetched from the target now, to avoid problems
2414 later when this internalvar is referenced and the target is gone or
2416 if (value_lazy (new_data.value))
2417 value_fetch_lazy (new_data.value);
2419 /* Release the value from the value chain to prevent it from being
2420 deleted by free_all_values. From here on this function should not
2421 call error () until new_data is installed into the var->u to avoid
2423 release_value (new_data.value);
2425 /* Internal variables which are created from values with a dynamic
2426 location don't need the location property of the origin anymore.
2427 The resolved dynamic location is used prior then any other address
2428 when accessing the value.
2429 If we keep it, we would still refer to the origin value.
2430 Remove the location property in case it exist. */
2431 remove_dyn_prop (DYN_PROP_DATA_LOCATION, value_type (new_data.value));
2436 /* Clean up old contents. */
2437 clear_internalvar (var);
2440 var->kind = new_kind;
2442 /* End code which must not call error(). */
2446 set_internalvar_integer (struct internalvar *var, LONGEST l)
2448 /* Clean up old contents. */
2449 clear_internalvar (var);
2451 var->kind = INTERNALVAR_INTEGER;
2452 var->u.integer.type = NULL;
2453 var->u.integer.val = l;
2457 set_internalvar_string (struct internalvar *var, const char *string)
2459 /* Clean up old contents. */
2460 clear_internalvar (var);
2462 var->kind = INTERNALVAR_STRING;
2463 var->u.string = xstrdup (string);
2467 set_internalvar_function (struct internalvar *var, struct internal_function *f)
2469 /* Clean up old contents. */
2470 clear_internalvar (var);
2472 var->kind = INTERNALVAR_FUNCTION;
2473 var->u.fn.function = f;
2474 var->u.fn.canonical = 1;
2475 /* Variables installed here are always the canonical version. */
2479 clear_internalvar (struct internalvar *var)
2481 /* Clean up old contents. */
2484 case INTERNALVAR_VALUE:
2485 value_free (var->u.value);
2488 case INTERNALVAR_STRING:
2489 xfree (var->u.string);
2492 case INTERNALVAR_MAKE_VALUE:
2493 if (var->u.make_value.functions->destroy != NULL)
2494 var->u.make_value.functions->destroy (var->u.make_value.data);
2501 /* Reset to void kind. */
2502 var->kind = INTERNALVAR_VOID;
2506 internalvar_name (const struct internalvar *var)
2511 static struct internal_function *
2512 create_internal_function (const char *name,
2513 internal_function_fn handler, void *cookie)
2515 struct internal_function *ifn = XNEW (struct internal_function);
2517 ifn->name = xstrdup (name);
2518 ifn->handler = handler;
2519 ifn->cookie = cookie;
2524 value_internal_function_name (struct value *val)
2526 struct internal_function *ifn;
2529 gdb_assert (VALUE_LVAL (val) == lval_internalvar);
2530 result = get_internalvar_function (VALUE_INTERNALVAR (val), &ifn);
2531 gdb_assert (result);
2537 call_internal_function (struct gdbarch *gdbarch,
2538 const struct language_defn *language,
2539 struct value *func, int argc, struct value **argv)
2541 struct internal_function *ifn;
2544 gdb_assert (VALUE_LVAL (func) == lval_internalvar);
2545 result = get_internalvar_function (VALUE_INTERNALVAR (func), &ifn);
2546 gdb_assert (result);
2548 return (*ifn->handler) (gdbarch, language, ifn->cookie, argc, argv);
2551 /* The 'function' command. This does nothing -- it is just a
2552 placeholder to let "help function NAME" work. This is also used as
2553 the implementation of the sub-command that is created when
2554 registering an internal function. */
2556 function_command (const char *command, int from_tty)
2561 /* Clean up if an internal function's command is destroyed. */
2563 function_destroyer (struct cmd_list_element *self, void *ignore)
2565 xfree ((char *) self->name);
2566 xfree ((char *) self->doc);
2569 /* Add a new internal function. NAME is the name of the function; DOC
2570 is a documentation string describing the function. HANDLER is
2571 called when the function is invoked. COOKIE is an arbitrary
2572 pointer which is passed to HANDLER and is intended for "user
2575 add_internal_function (const char *name, const char *doc,
2576 internal_function_fn handler, void *cookie)
2578 struct cmd_list_element *cmd;
2579 struct internal_function *ifn;
2580 struct internalvar *var = lookup_internalvar (name);
2582 ifn = create_internal_function (name, handler, cookie);
2583 set_internalvar_function (var, ifn);
2585 cmd = add_cmd (xstrdup (name), no_class, function_command, (char *) doc,
2587 cmd->destroyer = function_destroyer;
2590 /* Update VALUE before discarding OBJFILE. COPIED_TYPES is used to
2591 prevent cycles / duplicates. */
2594 preserve_one_value (struct value *value, struct objfile *objfile,
2595 htab_t copied_types)
2597 if (TYPE_OBJFILE (value->type) == objfile)
2598 value->type = copy_type_recursive (objfile, value->type, copied_types);
2600 if (TYPE_OBJFILE (value->enclosing_type) == objfile)
2601 value->enclosing_type = copy_type_recursive (objfile,
2602 value->enclosing_type,
2606 /* Likewise for internal variable VAR. */
2609 preserve_one_internalvar (struct internalvar *var, struct objfile *objfile,
2610 htab_t copied_types)
2614 case INTERNALVAR_INTEGER:
2615 if (var->u.integer.type && TYPE_OBJFILE (var->u.integer.type) == objfile)
2617 = copy_type_recursive (objfile, var->u.integer.type, copied_types);
2620 case INTERNALVAR_VALUE:
2621 preserve_one_value (var->u.value, objfile, copied_types);
2626 /* Update the internal variables and value history when OBJFILE is
2627 discarded; we must copy the types out of the objfile. New global types
2628 will be created for every convenience variable which currently points to
2629 this objfile's types, and the convenience variables will be adjusted to
2630 use the new global types. */
2633 preserve_values (struct objfile *objfile)
2635 htab_t copied_types;
2636 struct value_history_chunk *cur;
2637 struct internalvar *var;
2640 /* Create the hash table. We allocate on the objfile's obstack, since
2641 it is soon to be deleted. */
2642 copied_types = create_copied_types_hash (objfile);
2644 for (cur = value_history_chain; cur; cur = cur->next)
2645 for (i = 0; i < VALUE_HISTORY_CHUNK; i++)
2647 preserve_one_value (cur->values[i], objfile, copied_types);
2649 for (var = internalvars; var; var = var->next)
2650 preserve_one_internalvar (var, objfile, copied_types);
2652 preserve_ext_lang_values (objfile, copied_types);
2654 htab_delete (copied_types);
2658 show_convenience (const char *ignore, int from_tty)
2660 struct gdbarch *gdbarch = get_current_arch ();
2661 struct internalvar *var;
2663 struct value_print_options opts;
2665 get_user_print_options (&opts);
2666 for (var = internalvars; var; var = var->next)
2673 printf_filtered (("$%s = "), var->name);
2679 val = value_of_internalvar (gdbarch, var);
2680 value_print (val, gdb_stdout, &opts);
2682 CATCH (ex, RETURN_MASK_ERROR)
2684 fprintf_filtered (gdb_stdout, _("<error: %s>"), ex.message);
2688 printf_filtered (("\n"));
2692 /* This text does not mention convenience functions on purpose.
2693 The user can't create them except via Python, and if Python support
2694 is installed this message will never be printed ($_streq will
2696 printf_unfiltered (_("No debugger convenience variables now defined.\n"
2697 "Convenience variables have "
2698 "names starting with \"$\";\n"
2699 "use \"set\" as in \"set "
2700 "$foo = 5\" to define them.\n"));
2704 /* Return the TYPE_CODE_XMETHOD value corresponding to WORKER. */
2707 value_of_xmethod (struct xmethod_worker *worker)
2709 if (worker->value == NULL)
2713 v = allocate_value (builtin_type (target_gdbarch ())->xmethod);
2714 v->lval = lval_xcallable;
2715 v->location.xm_worker = worker;
2720 return worker->value;
2723 /* Return the type of the result of TYPE_CODE_XMETHOD value METHOD. */
2726 result_type_of_xmethod (struct value *method, int argc, struct value **argv)
2728 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2729 && method->lval == lval_xcallable && argc > 0);
2731 return get_xmethod_result_type (method->location.xm_worker,
2732 argv[0], argv + 1, argc - 1);
2735 /* Call the xmethod corresponding to the TYPE_CODE_XMETHOD value METHOD. */
2738 call_xmethod (struct value *method, int argc, struct value **argv)
2740 gdb_assert (TYPE_CODE (value_type (method)) == TYPE_CODE_XMETHOD
2741 && method->lval == lval_xcallable && argc > 0);
2743 return invoke_xmethod (method->location.xm_worker,
2744 argv[0], argv + 1, argc - 1);
2747 /* Extract a value as a C number (either long or double).
2748 Knows how to convert fixed values to double, or
2749 floating values to long.
2750 Does not deallocate the value. */
2753 value_as_long (struct value *val)
2755 /* This coerces arrays and functions, which is necessary (e.g.
2756 in disassemble_command). It also dereferences references, which
2757 I suspect is the most logical thing to do. */
2758 val = coerce_array (val);
2759 return unpack_long (value_type (val), value_contents (val));
2762 /* Extract a value as a C pointer. Does not deallocate the value.
2763 Note that val's type may not actually be a pointer; value_as_long
2764 handles all the cases. */
2766 value_as_address (struct value *val)
2768 struct gdbarch *gdbarch = get_type_arch (value_type (val));
2770 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2771 whether we want this to be true eventually. */
2773 /* gdbarch_addr_bits_remove is wrong if we are being called for a
2774 non-address (e.g. argument to "signal", "info break", etc.), or
2775 for pointers to char, in which the low bits *are* significant. */
2776 return gdbarch_addr_bits_remove (gdbarch, value_as_long (val));
2779 /* There are several targets (IA-64, PowerPC, and others) which
2780 don't represent pointers to functions as simply the address of
2781 the function's entry point. For example, on the IA-64, a
2782 function pointer points to a two-word descriptor, generated by
2783 the linker, which contains the function's entry point, and the
2784 value the IA-64 "global pointer" register should have --- to
2785 support position-independent code. The linker generates
2786 descriptors only for those functions whose addresses are taken.
2788 On such targets, it's difficult for GDB to convert an arbitrary
2789 function address into a function pointer; it has to either find
2790 an existing descriptor for that function, or call malloc and
2791 build its own. On some targets, it is impossible for GDB to
2792 build a descriptor at all: the descriptor must contain a jump
2793 instruction; data memory cannot be executed; and code memory
2796 Upon entry to this function, if VAL is a value of type `function'
2797 (that is, TYPE_CODE (VALUE_TYPE (val)) == TYPE_CODE_FUNC), then
2798 value_address (val) is the address of the function. This is what
2799 you'll get if you evaluate an expression like `main'. The call
2800 to COERCE_ARRAY below actually does all the usual unary
2801 conversions, which includes converting values of type `function'
2802 to `pointer to function'. This is the challenging conversion
2803 discussed above. Then, `unpack_long' will convert that pointer
2804 back into an address.
2806 So, suppose the user types `disassemble foo' on an architecture
2807 with a strange function pointer representation, on which GDB
2808 cannot build its own descriptors, and suppose further that `foo'
2809 has no linker-built descriptor. The address->pointer conversion
2810 will signal an error and prevent the command from running, even
2811 though the next step would have been to convert the pointer
2812 directly back into the same address.
2814 The following shortcut avoids this whole mess. If VAL is a
2815 function, just return its address directly. */
2816 if (TYPE_CODE (value_type (val)) == TYPE_CODE_FUNC
2817 || TYPE_CODE (value_type (val)) == TYPE_CODE_METHOD)
2818 return value_address (val);
2820 val = coerce_array (val);
2822 /* Some architectures (e.g. Harvard), map instruction and data
2823 addresses onto a single large unified address space. For
2824 instance: An architecture may consider a large integer in the
2825 range 0x10000000 .. 0x1000ffff to already represent a data
2826 addresses (hence not need a pointer to address conversion) while
2827 a small integer would still need to be converted integer to
2828 pointer to address. Just assume such architectures handle all
2829 integer conversions in a single function. */
2833 I think INTEGER_TO_ADDRESS is a good idea as proposed --- but we
2834 must admonish GDB hackers to make sure its behavior matches the
2835 compiler's, whenever possible.
2837 In general, I think GDB should evaluate expressions the same way
2838 the compiler does. When the user copies an expression out of
2839 their source code and hands it to a `print' command, they should
2840 get the same value the compiler would have computed. Any
2841 deviation from this rule can cause major confusion and annoyance,
2842 and needs to be justified carefully. In other words, GDB doesn't
2843 really have the freedom to do these conversions in clever and
2846 AndrewC pointed out that users aren't complaining about how GDB
2847 casts integers to pointers; they are complaining that they can't
2848 take an address from a disassembly listing and give it to `x/i'.
2849 This is certainly important.
2851 Adding an architecture method like integer_to_address() certainly
2852 makes it possible for GDB to "get it right" in all circumstances
2853 --- the target has complete control over how things get done, so
2854 people can Do The Right Thing for their target without breaking
2855 anyone else. The standard doesn't specify how integers get
2856 converted to pointers; usually, the ABI doesn't either, but
2857 ABI-specific code is a more reasonable place to handle it. */
2859 if (TYPE_CODE (value_type (val)) != TYPE_CODE_PTR
2860 && !TYPE_IS_REFERENCE (value_type (val))
2861 && gdbarch_integer_to_address_p (gdbarch))
2862 return gdbarch_integer_to_address (gdbarch, value_type (val),
2863 value_contents (val));
2865 return unpack_long (value_type (val), value_contents (val));
2869 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2870 as a long, or as a double, assuming the raw data is described
2871 by type TYPE. Knows how to convert different sizes of values
2872 and can convert between fixed and floating point. We don't assume
2873 any alignment for the raw data. Return value is in host byte order.
2875 If you want functions and arrays to be coerced to pointers, and
2876 references to be dereferenced, call value_as_long() instead.
2878 C++: It is assumed that the front-end has taken care of
2879 all matters concerning pointers to members. A pointer
2880 to member which reaches here is considered to be equivalent
2881 to an INT (or some size). After all, it is only an offset. */
2884 unpack_long (struct type *type, const gdb_byte *valaddr)
2886 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
2887 enum type_code code = TYPE_CODE (type);
2888 int len = TYPE_LENGTH (type);
2889 int nosign = TYPE_UNSIGNED (type);
2893 case TYPE_CODE_TYPEDEF:
2894 return unpack_long (check_typedef (type), valaddr);
2895 case TYPE_CODE_ENUM:
2896 case TYPE_CODE_FLAGS:
2897 case TYPE_CODE_BOOL:
2899 case TYPE_CODE_CHAR:
2900 case TYPE_CODE_RANGE:
2901 case TYPE_CODE_MEMBERPTR:
2903 return extract_unsigned_integer (valaddr, len, byte_order);
2905 return extract_signed_integer (valaddr, len, byte_order);
2908 case TYPE_CODE_DECFLOAT:
2909 return target_float_to_longest (valaddr, type);
2913 case TYPE_CODE_RVALUE_REF:
2914 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2915 whether we want this to be true eventually. */
2916 return extract_typed_address (valaddr, type);
2919 error (_("Value can't be converted to integer."));
2921 return 0; /* Placate lint. */
2924 /* Unpack raw data (copied from debugee, target byte order) at VALADDR
2925 as a CORE_ADDR, assuming the raw data is described by type TYPE.
2926 We don't assume any alignment for the raw data. Return value is in
2929 If you want functions and arrays to be coerced to pointers, and
2930 references to be dereferenced, call value_as_address() instead.
2932 C++: It is assumed that the front-end has taken care of
2933 all matters concerning pointers to members. A pointer
2934 to member which reaches here is considered to be equivalent
2935 to an INT (or some size). After all, it is only an offset. */
2938 unpack_pointer (struct type *type, const gdb_byte *valaddr)
2940 /* Assume a CORE_ADDR can fit in a LONGEST (for now). Not sure
2941 whether we want this to be true eventually. */
2942 return unpack_long (type, valaddr);
2946 is_floating_value (struct value *val)
2948 struct type *type = check_typedef (value_type (val));
2950 if (is_floating_type (type))
2952 if (!target_float_is_valid (value_contents (val), type))
2953 error (_("Invalid floating value found in program."));
2961 /* Get the value of the FIELDNO'th field (which must be static) of
2965 value_static_field (struct type *type, int fieldno)
2967 struct value *retval;
2969 switch (TYPE_FIELD_LOC_KIND (type, fieldno))
2971 case FIELD_LOC_KIND_PHYSADDR:
2972 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
2973 TYPE_FIELD_STATIC_PHYSADDR (type, fieldno));
2975 case FIELD_LOC_KIND_PHYSNAME:
2977 const char *phys_name = TYPE_FIELD_STATIC_PHYSNAME (type, fieldno);
2978 /* TYPE_FIELD_NAME (type, fieldno); */
2979 struct block_symbol sym = lookup_symbol (phys_name, 0, VAR_DOMAIN, 0);
2981 if (sym.symbol == NULL)
2983 /* With some compilers, e.g. HP aCC, static data members are
2984 reported as non-debuggable symbols. */
2985 struct bound_minimal_symbol msym
2986 = lookup_minimal_symbol (phys_name, NULL, NULL);
2989 return allocate_optimized_out_value (type);
2992 retval = value_at_lazy (TYPE_FIELD_TYPE (type, fieldno),
2993 BMSYMBOL_VALUE_ADDRESS (msym));
2997 retval = value_of_variable (sym.symbol, sym.block);
3001 gdb_assert_not_reached ("unexpected field location kind");
3007 /* Change the enclosing type of a value object VAL to NEW_ENCL_TYPE.
3008 You have to be careful here, since the size of the data area for the value
3009 is set by the length of the enclosing type. So if NEW_ENCL_TYPE is bigger
3010 than the old enclosing type, you have to allocate more space for the
3014 set_value_enclosing_type (struct value *val, struct type *new_encl_type)
3016 if (TYPE_LENGTH (new_encl_type) > TYPE_LENGTH (value_enclosing_type (val)))
3018 check_type_length_before_alloc (new_encl_type);
3020 = (gdb_byte *) xrealloc (val->contents, TYPE_LENGTH (new_encl_type));
3023 val->enclosing_type = new_encl_type;
3026 /* Given a value ARG1 (offset by OFFSET bytes)
3027 of a struct or union type ARG_TYPE,
3028 extract and return the value of one of its (non-static) fields.
3029 FIELDNO says which field. */
3032 value_primitive_field (struct value *arg1, LONGEST offset,
3033 int fieldno, struct type *arg_type)
3037 struct gdbarch *arch = get_value_arch (arg1);
3038 int unit_size = gdbarch_addressable_memory_unit_size (arch);
3040 arg_type = check_typedef (arg_type);
3041 type = TYPE_FIELD_TYPE (arg_type, fieldno);
3043 /* Call check_typedef on our type to make sure that, if TYPE
3044 is a TYPE_CODE_TYPEDEF, its length is set to the length
3045 of the target type instead of zero. However, we do not
3046 replace the typedef type by the target type, because we want
3047 to keep the typedef in order to be able to print the type
3048 description correctly. */
3049 check_typedef (type);
3051 if (TYPE_FIELD_BITSIZE (arg_type, fieldno))
3053 /* Handle packed fields.
3055 Create a new value for the bitfield, with bitpos and bitsize
3056 set. If possible, arrange offset and bitpos so that we can
3057 do a single aligned read of the size of the containing type.
3058 Otherwise, adjust offset to the byte containing the first
3059 bit. Assume that the address, offset, and embedded offset
3060 are sufficiently aligned. */
3062 LONGEST bitpos = TYPE_FIELD_BITPOS (arg_type, fieldno);
3063 LONGEST container_bitsize = TYPE_LENGTH (type) * 8;
3065 v = allocate_value_lazy (type);
3066 v->bitsize = TYPE_FIELD_BITSIZE (arg_type, fieldno);
3067 if ((bitpos % container_bitsize) + v->bitsize <= container_bitsize
3068 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST))
3069 v->bitpos = bitpos % container_bitsize;
3071 v->bitpos = bitpos % 8;
3072 v->offset = (value_embedded_offset (arg1)
3074 + (bitpos - v->bitpos) / 8);
3075 set_value_parent (v, arg1);
3076 if (!value_lazy (arg1))
3077 value_fetch_lazy (v);
3079 else if (fieldno < TYPE_N_BASECLASSES (arg_type))
3081 /* This field is actually a base subobject, so preserve the
3082 entire object's contents for later references to virtual
3086 /* Lazy register values with offsets are not supported. */
3087 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3088 value_fetch_lazy (arg1);
3090 /* We special case virtual inheritance here because this
3091 requires access to the contents, which we would rather avoid
3092 for references to ordinary fields of unavailable values. */
3093 if (BASETYPE_VIA_VIRTUAL (arg_type, fieldno))
3094 boffset = baseclass_offset (arg_type, fieldno,
3095 value_contents (arg1),
3096 value_embedded_offset (arg1),
3097 value_address (arg1),
3100 boffset = TYPE_FIELD_BITPOS (arg_type, fieldno) / 8;
3102 if (value_lazy (arg1))
3103 v = allocate_value_lazy (value_enclosing_type (arg1));
3106 v = allocate_value (value_enclosing_type (arg1));
3107 value_contents_copy_raw (v, 0, arg1, 0,
3108 TYPE_LENGTH (value_enclosing_type (arg1)));
3111 v->offset = value_offset (arg1);
3112 v->embedded_offset = offset + value_embedded_offset (arg1) + boffset;
3114 else if (NULL != TYPE_DATA_LOCATION (type))
3116 /* Field is a dynamic data member. */
3118 gdb_assert (0 == offset);
3119 /* We expect an already resolved data location. */
3120 gdb_assert (PROP_CONST == TYPE_DATA_LOCATION_KIND (type));
3121 /* For dynamic data types defer memory allocation
3122 until we actual access the value. */
3123 v = allocate_value_lazy (type);
3127 /* Plain old data member */
3128 offset += (TYPE_FIELD_BITPOS (arg_type, fieldno)
3129 / (HOST_CHAR_BIT * unit_size));
3131 /* Lazy register values with offsets are not supported. */
3132 if (VALUE_LVAL (arg1) == lval_register && value_lazy (arg1))
3133 value_fetch_lazy (arg1);
3135 if (value_lazy (arg1))
3136 v = allocate_value_lazy (type);
3139 v = allocate_value (type);
3140 value_contents_copy_raw (v, value_embedded_offset (v),
3141 arg1, value_embedded_offset (arg1) + offset,
3142 type_length_units (type));
3144 v->offset = (value_offset (arg1) + offset
3145 + value_embedded_offset (arg1));
3147 set_value_component_location (v, arg1);
3151 /* Given a value ARG1 of a struct or union type,
3152 extract and return the value of one of its (non-static) fields.
3153 FIELDNO says which field. */
3156 value_field (struct value *arg1, int fieldno)
3158 return value_primitive_field (arg1, 0, fieldno, value_type (arg1));
3161 /* Return a non-virtual function as a value.
3162 F is the list of member functions which contains the desired method.
3163 J is an index into F which provides the desired method.
3165 We only use the symbol for its address, so be happy with either a
3166 full symbol or a minimal symbol. */
3169 value_fn_field (struct value **arg1p, struct fn_field *f,
3170 int j, struct type *type,
3174 struct type *ftype = TYPE_FN_FIELD_TYPE (f, j);
3175 const char *physname = TYPE_FN_FIELD_PHYSNAME (f, j);
3177 struct bound_minimal_symbol msym;
3179 sym = lookup_symbol (physname, 0, VAR_DOMAIN, 0).symbol;
3182 memset (&msym, 0, sizeof (msym));
3186 gdb_assert (sym == NULL);
3187 msym = lookup_bound_minimal_symbol (physname);
3188 if (msym.minsym == NULL)
3192 v = allocate_value (ftype);
3193 VALUE_LVAL (v) = lval_memory;
3196 set_value_address (v, BLOCK_START (SYMBOL_BLOCK_VALUE (sym)));
3200 /* The minimal symbol might point to a function descriptor;
3201 resolve it to the actual code address instead. */
3202 struct objfile *objfile = msym.objfile;
3203 struct gdbarch *gdbarch = get_objfile_arch (objfile);
3205 set_value_address (v,
3206 gdbarch_convert_from_func_ptr_addr
3207 (gdbarch, BMSYMBOL_VALUE_ADDRESS (msym), ¤t_target));
3212 if (type != value_type (*arg1p))
3213 *arg1p = value_ind (value_cast (lookup_pointer_type (type),
3214 value_addr (*arg1p)));
3216 /* Move the `this' pointer according to the offset.
3217 VALUE_OFFSET (*arg1p) += offset; */
3225 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at
3226 VALADDR, and store the result in *RESULT.
3227 The bitfield starts at BITPOS bits and contains BITSIZE bits.
3229 Extracting bits depends on endianness of the machine. Compute the
3230 number of least significant bits to discard. For big endian machines,
3231 we compute the total number of bits in the anonymous object, subtract
3232 off the bit count from the MSB of the object to the MSB of the
3233 bitfield, then the size of the bitfield, which leaves the LSB discard
3234 count. For little endian machines, the discard count is simply the
3235 number of bits from the LSB of the anonymous object to the LSB of the
3238 If the field is signed, we also do sign extension. */
3241 unpack_bits_as_long (struct type *field_type, const gdb_byte *valaddr,
3242 LONGEST bitpos, LONGEST bitsize)
3244 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (field_type));
3249 LONGEST read_offset;
3251 /* Read the minimum number of bytes required; there may not be
3252 enough bytes to read an entire ULONGEST. */
3253 field_type = check_typedef (field_type);
3255 bytes_read = ((bitpos % 8) + bitsize + 7) / 8;
3257 bytes_read = TYPE_LENGTH (field_type);
3259 read_offset = bitpos / 8;
3261 val = extract_unsigned_integer (valaddr + read_offset,
3262 bytes_read, byte_order);
3264 /* Extract bits. See comment above. */
3266 if (gdbarch_bits_big_endian (get_type_arch (field_type)))
3267 lsbcount = (bytes_read * 8 - bitpos % 8 - bitsize);
3269 lsbcount = (bitpos % 8);
3272 /* If the field does not entirely fill a LONGEST, then zero the sign bits.
3273 If the field is signed, and is negative, then sign extend. */
3275 if ((bitsize > 0) && (bitsize < 8 * (int) sizeof (val)))
3277 valmask = (((ULONGEST) 1) << bitsize) - 1;
3279 if (!TYPE_UNSIGNED (field_type))
3281 if (val & (valmask ^ (valmask >> 1)))
3291 /* Unpack a field FIELDNO of the specified TYPE, from the object at
3292 VALADDR + EMBEDDED_OFFSET. VALADDR points to the contents of
3293 ORIGINAL_VALUE, which must not be NULL. See
3294 unpack_value_bits_as_long for more details. */
3297 unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
3298 LONGEST embedded_offset, int fieldno,
3299 const struct value *val, LONGEST *result)
3301 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3302 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3303 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3306 gdb_assert (val != NULL);
3308 bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3309 if (value_bits_any_optimized_out (val, bit_offset, bitsize)
3310 || !value_bits_available (val, bit_offset, bitsize))
3313 *result = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3318 /* Unpack a field FIELDNO of the specified TYPE, from the anonymous
3319 object at VALADDR. See unpack_bits_as_long for more details. */
3322 unpack_field_as_long (struct type *type, const gdb_byte *valaddr, int fieldno)
3324 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3325 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3326 struct type *field_type = TYPE_FIELD_TYPE (type, fieldno);
3328 return unpack_bits_as_long (field_type, valaddr, bitpos, bitsize);
3331 /* Unpack a bitfield of BITSIZE bits found at BITPOS in the object at
3332 VALADDR + EMBEDDEDOFFSET that has the type of DEST_VAL and store
3333 the contents in DEST_VAL, zero or sign extending if the type of
3334 DEST_VAL is wider than BITSIZE. VALADDR points to the contents of
3335 VAL. If the VAL's contents required to extract the bitfield from
3336 are unavailable/optimized out, DEST_VAL is correspondingly
3337 marked unavailable/optimized out. */
3340 unpack_value_bitfield (struct value *dest_val,
3341 LONGEST bitpos, LONGEST bitsize,
3342 const gdb_byte *valaddr, LONGEST embedded_offset,
3343 const struct value *val)
3345 enum bfd_endian byte_order;
3348 struct type *field_type = value_type (dest_val);
3350 byte_order = gdbarch_byte_order (get_type_arch (field_type));
3352 /* First, unpack and sign extend the bitfield as if it was wholly
3353 valid. Optimized out/unavailable bits are read as zero, but
3354 that's OK, as they'll end up marked below. If the VAL is
3355 wholly-invalid we may have skipped allocating its contents,
3356 though. See allocate_optimized_out_value. */
3357 if (valaddr != NULL)
3361 num = unpack_bits_as_long (field_type, valaddr + embedded_offset,
3363 store_signed_integer (value_contents_raw (dest_val),
3364 TYPE_LENGTH (field_type), byte_order, num);
3367 /* Now copy the optimized out / unavailability ranges to the right
3369 src_bit_offset = embedded_offset * TARGET_CHAR_BIT + bitpos;
3370 if (byte_order == BFD_ENDIAN_BIG)
3371 dst_bit_offset = TYPE_LENGTH (field_type) * TARGET_CHAR_BIT - bitsize;
3374 value_ranges_copy_adjusted (dest_val, dst_bit_offset,
3375 val, src_bit_offset, bitsize);
3378 /* Return a new value with type TYPE, which is FIELDNO field of the
3379 object at VALADDR + EMBEDDEDOFFSET. VALADDR points to the contents
3380 of VAL. If the VAL's contents required to extract the bitfield
3381 from are unavailable/optimized out, the new value is
3382 correspondingly marked unavailable/optimized out. */
3385 value_field_bitfield (struct type *type, int fieldno,
3386 const gdb_byte *valaddr,
3387 LONGEST embedded_offset, const struct value *val)
3389 int bitpos = TYPE_FIELD_BITPOS (type, fieldno);
3390 int bitsize = TYPE_FIELD_BITSIZE (type, fieldno);
3391 struct value *res_val = allocate_value (TYPE_FIELD_TYPE (type, fieldno));
3393 unpack_value_bitfield (res_val, bitpos, bitsize,
3394 valaddr, embedded_offset, val);
3399 /* Modify the value of a bitfield. ADDR points to a block of memory in
3400 target byte order; the bitfield starts in the byte pointed to. FIELDVAL
3401 is the desired value of the field, in host byte order. BITPOS and BITSIZE
3402 indicate which bits (in target bit order) comprise the bitfield.
3403 Requires 0 < BITSIZE <= lbits, 0 <= BITPOS % 8 + BITSIZE <= lbits, and
3404 0 <= BITPOS, where lbits is the size of a LONGEST in bits. */
3407 modify_field (struct type *type, gdb_byte *addr,
3408 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize)
3410 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3412 ULONGEST mask = (ULONGEST) -1 >> (8 * sizeof (ULONGEST) - bitsize);
3415 /* Normalize BITPOS. */
3419 /* If a negative fieldval fits in the field in question, chop
3420 off the sign extension bits. */
3421 if ((~fieldval & ~(mask >> 1)) == 0)
3424 /* Warn if value is too big to fit in the field in question. */
3425 if (0 != (fieldval & ~mask))
3427 /* FIXME: would like to include fieldval in the message, but
3428 we don't have a sprintf_longest. */
3429 warning (_("Value does not fit in %s bits."), plongest (bitsize));
3431 /* Truncate it, otherwise adjoining fields may be corrupted. */
3435 /* Ensure no bytes outside of the modified ones get accessed as it may cause
3436 false valgrind reports. */
3438 bytesize = (bitpos + bitsize + 7) / 8;
3439 oword = extract_unsigned_integer (addr, bytesize, byte_order);
3441 /* Shifting for bit field depends on endianness of the target machine. */
3442 if (gdbarch_bits_big_endian (get_type_arch (type)))
3443 bitpos = bytesize * 8 - bitpos - bitsize;
3445 oword &= ~(mask << bitpos);
3446 oword |= fieldval << bitpos;
3448 store_unsigned_integer (addr, bytesize, byte_order, oword);
3451 /* Pack NUM into BUF using a target format of TYPE. */
3454 pack_long (gdb_byte *buf, struct type *type, LONGEST num)
3456 enum bfd_endian byte_order = gdbarch_byte_order (get_type_arch (type));
3459 type = check_typedef (type);
3460 len = TYPE_LENGTH (type);
3462 switch (TYPE_CODE (type))
3465 case TYPE_CODE_CHAR:
3466 case TYPE_CODE_ENUM:
3467 case TYPE_CODE_FLAGS:
3468 case TYPE_CODE_BOOL:
3469 case TYPE_CODE_RANGE:
3470 case TYPE_CODE_MEMBERPTR:
3471 store_signed_integer (buf, len, byte_order, num);
3475 case TYPE_CODE_RVALUE_REF:
3477 store_typed_address (buf, type, (CORE_ADDR) num);
3481 case TYPE_CODE_DECFLOAT:
3482 target_float_from_longest (buf, type, num);
3486 error (_("Unexpected type (%d) encountered for integer constant."),
3492 /* Pack NUM into BUF using a target format of TYPE. */
3495 pack_unsigned_long (gdb_byte *buf, struct type *type, ULONGEST num)
3498 enum bfd_endian byte_order;
3500 type = check_typedef (type);
3501 len = TYPE_LENGTH (type);
3502 byte_order = gdbarch_byte_order (get_type_arch (type));
3504 switch (TYPE_CODE (type))
3507 case TYPE_CODE_CHAR:
3508 case TYPE_CODE_ENUM:
3509 case TYPE_CODE_FLAGS:
3510 case TYPE_CODE_BOOL:
3511 case TYPE_CODE_RANGE:
3512 case TYPE_CODE_MEMBERPTR:
3513 store_unsigned_integer (buf, len, byte_order, num);
3517 case TYPE_CODE_RVALUE_REF:
3519 store_typed_address (buf, type, (CORE_ADDR) num);
3523 case TYPE_CODE_DECFLOAT:
3524 target_float_from_ulongest (buf, type, num);
3528 error (_("Unexpected type (%d) encountered "
3529 "for unsigned integer constant."),
3535 /* Convert C numbers into newly allocated values. */
3538 value_from_longest (struct type *type, LONGEST num)
3540 struct value *val = allocate_value (type);
3542 pack_long (value_contents_raw (val), type, num);
3547 /* Convert C unsigned numbers into newly allocated values. */
3550 value_from_ulongest (struct type *type, ULONGEST num)
3552 struct value *val = allocate_value (type);
3554 pack_unsigned_long (value_contents_raw (val), type, num);
3560 /* Create a value representing a pointer of type TYPE to the address
3564 value_from_pointer (struct type *type, CORE_ADDR addr)
3566 struct value *val = allocate_value (type);
3568 store_typed_address (value_contents_raw (val),
3569 check_typedef (type), addr);
3574 /* Create a value of type TYPE whose contents come from VALADDR, if it
3575 is non-null, and whose memory address (in the inferior) is
3576 ADDRESS. The type of the created value may differ from the passed
3577 type TYPE. Make sure to retrieve values new type after this call.
3578 Note that TYPE is not passed through resolve_dynamic_type; this is
3579 a special API intended for use only by Ada. */
3582 value_from_contents_and_address_unresolved (struct type *type,
3583 const gdb_byte *valaddr,
3588 if (valaddr == NULL)
3589 v = allocate_value_lazy (type);
3591 v = value_from_contents (type, valaddr);
3592 VALUE_LVAL (v) = lval_memory;
3593 set_value_address (v, address);
3597 /* Create a value of type TYPE whose contents come from VALADDR, if it
3598 is non-null, and whose memory address (in the inferior) is
3599 ADDRESS. The type of the created value may differ from the passed
3600 type TYPE. Make sure to retrieve values new type after this call. */
3603 value_from_contents_and_address (struct type *type,
3604 const gdb_byte *valaddr,
3607 struct type *resolved_type = resolve_dynamic_type (type, valaddr, address);
3608 struct type *resolved_type_no_typedef = check_typedef (resolved_type);
3611 if (valaddr == NULL)
3612 v = allocate_value_lazy (resolved_type);
3614 v = value_from_contents (resolved_type, valaddr);
3615 if (TYPE_DATA_LOCATION (resolved_type_no_typedef) != NULL
3616 && TYPE_DATA_LOCATION_KIND (resolved_type_no_typedef) == PROP_CONST)
3617 address = TYPE_DATA_LOCATION_ADDR (resolved_type_no_typedef);
3618 VALUE_LVAL (v) = lval_memory;
3619 set_value_address (v, address);
3623 /* Create a value of type TYPE holding the contents CONTENTS.
3624 The new value is `not_lval'. */
3627 value_from_contents (struct type *type, const gdb_byte *contents)
3629 struct value *result;
3631 result = allocate_value (type);
3632 memcpy (value_contents_raw (result), contents, TYPE_LENGTH (type));
3636 /* Extract a value from the history file. Input will be of the form
3637 $digits or $$digits. See block comment above 'write_dollar_variable'
3641 value_from_history_ref (const char *h, const char **endp)
3653 /* Find length of numeral string. */
3654 for (; isdigit (h[len]); len++)
3657 /* Make sure numeral string is not part of an identifier. */
3658 if (h[len] == '_' || isalpha (h[len]))
3661 /* Now collect the index value. */
3666 /* For some bizarre reason, "$$" is equivalent to "$$1",
3667 rather than to "$$0" as it ought to be! */
3675 index = -strtol (&h[2], &local_end, 10);
3683 /* "$" is equivalent to "$0". */
3691 index = strtol (&h[1], &local_end, 10);
3696 return access_value_history (index);
3699 /* Get the component value (offset by OFFSET bytes) of a struct or
3700 union WHOLE. Component's type is TYPE. */
3703 value_from_component (struct value *whole, struct type *type, LONGEST offset)
3707 if (VALUE_LVAL (whole) == lval_memory && value_lazy (whole))
3708 v = allocate_value_lazy (type);
3711 v = allocate_value (type);
3712 value_contents_copy (v, value_embedded_offset (v),
3713 whole, value_embedded_offset (whole) + offset,
3714 type_length_units (type));
3716 v->offset = value_offset (whole) + offset + value_embedded_offset (whole);
3717 set_value_component_location (v, whole);
3723 coerce_ref_if_computed (const struct value *arg)
3725 const struct lval_funcs *funcs;
3727 if (!TYPE_IS_REFERENCE (check_typedef (value_type (arg))))
3730 if (value_lval_const (arg) != lval_computed)
3733 funcs = value_computed_funcs (arg);
3734 if (funcs->coerce_ref == NULL)
3737 return funcs->coerce_ref (arg);
3740 /* Look at value.h for description. */
3743 readjust_indirect_value_type (struct value *value, struct type *enc_type,
3744 const struct type *original_type,
3745 const struct value *original_value)
3747 /* Re-adjust type. */
3748 deprecated_set_value_type (value, TYPE_TARGET_TYPE (original_type));
3750 /* Add embedding info. */
3751 set_value_enclosing_type (value, enc_type);
3752 set_value_embedded_offset (value, value_pointed_to_offset (original_value));
3754 /* We may be pointing to an object of some derived type. */
3755 return value_full_object (value, NULL, 0, 0, 0);
3759 coerce_ref (struct value *arg)
3761 struct type *value_type_arg_tmp = check_typedef (value_type (arg));
3762 struct value *retval;
3763 struct type *enc_type;
3765 retval = coerce_ref_if_computed (arg);
3769 if (!TYPE_IS_REFERENCE (value_type_arg_tmp))
3772 enc_type = check_typedef (value_enclosing_type (arg));
3773 enc_type = TYPE_TARGET_TYPE (enc_type);
3775 retval = value_at_lazy (enc_type,
3776 unpack_pointer (value_type (arg),
3777 value_contents (arg)));
3778 enc_type = value_type (retval);
3779 return readjust_indirect_value_type (retval, enc_type,
3780 value_type_arg_tmp, arg);
3784 coerce_array (struct value *arg)
3788 arg = coerce_ref (arg);
3789 type = check_typedef (value_type (arg));
3791 switch (TYPE_CODE (type))
3793 case TYPE_CODE_ARRAY:
3794 if (!TYPE_VECTOR (type) && current_language->c_style_arrays)
3795 arg = value_coerce_array (arg);
3797 case TYPE_CODE_FUNC:
3798 arg = value_coerce_function (arg);
3805 /* Return the return value convention that will be used for the
3808 enum return_value_convention
3809 struct_return_convention (struct gdbarch *gdbarch,
3810 struct value *function, struct type *value_type)
3812 enum type_code code = TYPE_CODE (value_type);
3814 if (code == TYPE_CODE_ERROR)
3815 error (_("Function return type unknown."));
3817 /* Probe the architecture for the return-value convention. */
3818 return gdbarch_return_value (gdbarch, function, value_type,
3822 /* Return true if the function returning the specified type is using
3823 the convention of returning structures in memory (passing in the
3824 address as a hidden first parameter). */
3827 using_struct_return (struct gdbarch *gdbarch,
3828 struct value *function, struct type *value_type)
3830 if (TYPE_CODE (value_type) == TYPE_CODE_VOID)
3831 /* A void return value is never in memory. See also corresponding
3832 code in "print_return_value". */
3835 return (struct_return_convention (gdbarch, function, value_type)
3836 != RETURN_VALUE_REGISTER_CONVENTION);
3839 /* Set the initialized field in a value struct. */
3842 set_value_initialized (struct value *val, int status)
3844 val->initialized = status;
3847 /* Return the initialized field in a value struct. */
3850 value_initialized (const struct value *val)
3852 return val->initialized;
3855 /* Load the actual content of a lazy value. Fetch the data from the
3856 user's process and clear the lazy flag to indicate that the data in
3857 the buffer is valid.
3859 If the value is zero-length, we avoid calling read_memory, which
3860 would abort. We mark the value as fetched anyway -- all 0 bytes of
3864 value_fetch_lazy (struct value *val)
3866 gdb_assert (value_lazy (val));
3867 allocate_value_contents (val);
3868 /* A value is either lazy, or fully fetched. The
3869 availability/validity is only established as we try to fetch a
3871 gdb_assert (VEC_empty (range_s, val->optimized_out));
3872 gdb_assert (VEC_empty (range_s, val->unavailable));
3873 if (value_bitsize (val))
3875 /* To read a lazy bitfield, read the entire enclosing value. This
3876 prevents reading the same block of (possibly volatile) memory once
3877 per bitfield. It would be even better to read only the containing
3878 word, but we have no way to record that just specific bits of a
3879 value have been fetched. */
3880 struct type *type = check_typedef (value_type (val));
3881 struct value *parent = value_parent (val);
3883 if (value_lazy (parent))
3884 value_fetch_lazy (parent);
3886 unpack_value_bitfield (val,
3887 value_bitpos (val), value_bitsize (val),
3888 value_contents_for_printing (parent),
3889 value_offset (val), parent);
3891 else if (VALUE_LVAL (val) == lval_memory)
3893 CORE_ADDR addr = value_address (val);
3894 struct type *type = check_typedef (value_enclosing_type (val));
3896 if (TYPE_LENGTH (type))
3897 read_value_memory (val, 0, value_stack (val),
3898 addr, value_contents_all_raw (val),
3899 type_length_units (type));
3901 else if (VALUE_LVAL (val) == lval_register)
3903 struct frame_info *next_frame;
3905 struct type *type = check_typedef (value_type (val));
3906 struct value *new_val = val, *mark = value_mark ();
3908 /* Offsets are not supported here; lazy register values must
3909 refer to the entire register. */
3910 gdb_assert (value_offset (val) == 0);
3912 while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
3914 struct frame_id next_frame_id = VALUE_NEXT_FRAME_ID (new_val);
3916 next_frame = frame_find_by_id (next_frame_id);
3917 regnum = VALUE_REGNUM (new_val);
3919 gdb_assert (next_frame != NULL);
3921 /* Convertible register routines are used for multi-register
3922 values and for interpretation in different types
3923 (e.g. float or int from a double register). Lazy
3924 register values should have the register's natural type,
3925 so they do not apply. */
3926 gdb_assert (!gdbarch_convert_register_p (get_frame_arch (next_frame),
3929 /* FRAME was obtained, above, via VALUE_NEXT_FRAME_ID.
3930 Since a "->next" operation was performed when setting
3931 this field, we do not need to perform a "next" operation
3932 again when unwinding the register. That's why
3933 frame_unwind_register_value() is called here instead of
3934 get_frame_register_value(). */
3935 new_val = frame_unwind_register_value (next_frame, regnum);
3937 /* If we get another lazy lval_register value, it means the
3938 register is found by reading it from NEXT_FRAME's next frame.
3939 frame_unwind_register_value should never return a value with
3940 the frame id pointing to NEXT_FRAME. If it does, it means we
3941 either have two consecutive frames with the same frame id
3942 in the frame chain, or some code is trying to unwind
3943 behind get_prev_frame's back (e.g., a frame unwind
3944 sniffer trying to unwind), bypassing its validations. In
3945 any case, it should always be an internal error to end up
3946 in this situation. */
3947 if (VALUE_LVAL (new_val) == lval_register
3948 && value_lazy (new_val)
3949 && frame_id_eq (VALUE_NEXT_FRAME_ID (new_val), next_frame_id))
3950 internal_error (__FILE__, __LINE__,
3951 _("infinite loop while fetching a register"));
3954 /* If it's still lazy (for instance, a saved register on the
3955 stack), fetch it. */
3956 if (value_lazy (new_val))
3957 value_fetch_lazy (new_val);
3959 /* Copy the contents and the unavailability/optimized-out
3960 meta-data from NEW_VAL to VAL. */
3961 set_value_lazy (val, 0);
3962 value_contents_copy (val, value_embedded_offset (val),
3963 new_val, value_embedded_offset (new_val),
3964 type_length_units (type));
3968 struct gdbarch *gdbarch;
3969 struct frame_info *frame;
3970 /* VALUE_FRAME_ID is used here, instead of VALUE_NEXT_FRAME_ID,
3971 so that the frame level will be shown correctly. */
3972 frame = frame_find_by_id (VALUE_FRAME_ID (val));
3973 regnum = VALUE_REGNUM (val);
3974 gdbarch = get_frame_arch (frame);
3976 fprintf_unfiltered (gdb_stdlog,
3977 "{ value_fetch_lazy "
3978 "(frame=%d,regnum=%d(%s),...) ",
3979 frame_relative_level (frame), regnum,
3980 user_reg_map_regnum_to_name (gdbarch, regnum));
3982 fprintf_unfiltered (gdb_stdlog, "->");
3983 if (value_optimized_out (new_val))
3985 fprintf_unfiltered (gdb_stdlog, " ");
3986 val_print_optimized_out (new_val, gdb_stdlog);
3991 const gdb_byte *buf = value_contents (new_val);
3993 if (VALUE_LVAL (new_val) == lval_register)
3994 fprintf_unfiltered (gdb_stdlog, " register=%d",
3995 VALUE_REGNUM (new_val));
3996 else if (VALUE_LVAL (new_val) == lval_memory)
3997 fprintf_unfiltered (gdb_stdlog, " address=%s",
3999 value_address (new_val)));
4001 fprintf_unfiltered (gdb_stdlog, " computed");
4003 fprintf_unfiltered (gdb_stdlog, " bytes=");
4004 fprintf_unfiltered (gdb_stdlog, "[");
4005 for (i = 0; i < register_size (gdbarch, regnum); i++)
4006 fprintf_unfiltered (gdb_stdlog, "%02x", buf[i]);
4007 fprintf_unfiltered (gdb_stdlog, "]");
4010 fprintf_unfiltered (gdb_stdlog, " }\n");
4013 /* Dispose of the intermediate values. This prevents
4014 watchpoints from trying to watch the saved frame pointer. */
4015 value_free_to_mark (mark);
4017 else if (VALUE_LVAL (val) == lval_computed
4018 && value_computed_funcs (val)->read != NULL)
4019 value_computed_funcs (val)->read (val);
4021 internal_error (__FILE__, __LINE__, _("Unexpected lazy value type."));
4023 set_value_lazy (val, 0);
4026 /* Implementation of the convenience function $_isvoid. */
4028 static struct value *
4029 isvoid_internal_fn (struct gdbarch *gdbarch,
4030 const struct language_defn *language,
4031 void *cookie, int argc, struct value **argv)
4036 error (_("You must provide one argument for $_isvoid."));
4038 ret = TYPE_CODE (value_type (argv[0])) == TYPE_CODE_VOID;
4040 return value_from_longest (builtin_type (gdbarch)->builtin_int, ret);
4044 _initialize_values (void)
4046 add_cmd ("convenience", no_class, show_convenience, _("\
4047 Debugger convenience (\"$foo\") variables and functions.\n\
4048 Convenience variables are created when you assign them values;\n\
4049 thus, \"set $foo=1\" gives \"$foo\" the value 1. Values may be any type.\n\
4051 A few convenience variables are given values automatically:\n\
4052 \"$_\"holds the last address examined with \"x\" or \"info lines\",\n\
4053 \"$__\" holds the contents of the last address examined with \"x\"."
4056 Convenience functions are defined via the Python API."
4059 add_alias_cmd ("conv", "convenience", no_class, 1, &showlist);
4061 add_cmd ("values", no_set_class, show_values, _("\
4062 Elements of value history around item number IDX (or last ten)."),
4065 add_com ("init-if-undefined", class_vars, init_if_undefined_command, _("\
4066 Initialize a convenience variable if necessary.\n\
4067 init-if-undefined VARIABLE = EXPRESSION\n\
4068 Set an internal VARIABLE to the result of the EXPRESSION if it does not\n\
4069 exist or does not contain a value. The EXPRESSION is not evaluated if the\n\
4070 VARIABLE is already initialized."));
4072 add_prefix_cmd ("function", no_class, function_command, _("\
4073 Placeholder command for showing help on convenience functions."),
4074 &functionlist, "function ", 0, &cmdlist);
4076 add_internal_function ("_isvoid", _("\
4077 Check whether an expression is void.\n\
4078 Usage: $_isvoid (expression)\n\
4079 Return 1 if the expression is void, zero otherwise."),
4080 isvoid_internal_fn, NULL);
4082 add_setshow_zuinteger_unlimited_cmd ("max-value-size",
4083 class_support, &max_value_size, _("\
4084 Set maximum sized value gdb will load from the inferior."), _("\
4085 Show maximum sized value gdb will load from the inferior."), _("\
4086 Use this to control the maximum size, in bytes, of a value that gdb\n\
4087 will load from the inferior. Setting this value to 'unlimited'\n\
4088 disables checking.\n\
4089 Setting this does not invalidate already allocated values, it only\n\
4090 prevents future values, larger than this size, from being allocated."),
4092 show_max_value_size,
4093 &setlist, &showlist);