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[binutils-gdb/blckswan.git] / gdb / value.h
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1 /* Definitions for values of C expressions, for GDB.
3 Copyright (C) 1986-2022 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/>. */
20 #if !defined (VALUE_H)
21 #define VALUE_H 1
23 #include "frame.h" /* For struct frame_id. */
24 #include "extension.h"
25 #include "gdbsupport/gdb_ref_ptr.h"
26 #include "gmp-utils.h"
28 struct block;
29 struct expression;
30 struct regcache;
31 struct symbol;
32 struct type;
33 struct ui_file;
34 struct language_defn;
35 struct value_print_options;
37 /* Values can be partially 'optimized out' and/or 'unavailable'.
38 These are distinct states and have different string representations
39 and related error strings.
41 'unavailable' has a specific meaning in this context. It means the
42 value exists in the program (at the machine level), but GDB has no
43 means to get to it. Such a value is normally printed as
44 <unavailable>. Examples of how to end up with an unavailable value
45 would be:
47 - We're inspecting a traceframe, and the memory or registers the
48 debug information says the value lives on haven't been collected.
50 - We're inspecting a core dump, the memory or registers the debug
51 information says the value lives aren't present in the dump
52 (that is, we have a partial/trimmed core dump, or we don't fully
53 understand/handle the core dump's format).
55 - We're doing live debugging, but the debug API has no means to
56 get at where the value lives in the machine, like e.g., ptrace
57 not having access to some register or register set.
59 - Any other similar scenario.
61 OTOH, "optimized out" is about what the compiler decided to generate
62 (or not generate). A chunk of a value that was optimized out does
63 not actually exist in the program. There's no way to get at it
64 short of compiling the program differently.
66 A register that has not been saved in a frame is likewise considered
67 optimized out, except not-saved registers have a different string
68 representation and related error strings. E.g., we'll print them as
69 <not-saved> instead of <optimized out>, as in:
71 (gdb) p/x $rax
72 $1 = <not saved>
73 (gdb) info registers rax
74 rax <not saved>
76 If the debug info describes a variable as being in such a register,
77 we'll still print the variable as <optimized out>. IOW, <not saved>
78 is reserved for inspecting registers at the machine level.
80 When comparing value contents, optimized out chunks, unavailable
81 chunks, and valid contents data are all considered different. See
82 value_contents_eq for more info.
85 extern bool overload_resolution;
87 /* The structure which defines the type of a value. It should never
88 be possible for a program lval value to survive over a call to the
89 inferior (i.e. to be put into the history list or an internal
90 variable). */
92 struct value;
94 /* Increase VAL's reference count. */
96 extern void value_incref (struct value *val);
98 /* Decrease VAL's reference count. When the reference count drops to
99 0, VAL will be freed. */
101 extern void value_decref (struct value *val);
103 /* A policy class to interface gdb::ref_ptr with struct value. */
105 struct value_ref_policy
107 static void incref (struct value *ptr)
109 value_incref (ptr);
112 static void decref (struct value *ptr)
114 value_decref (ptr);
118 /* A gdb:;ref_ptr pointer to a struct value. */
120 typedef gdb::ref_ptr<struct value, value_ref_policy> value_ref_ptr;
122 /* Values are stored in a chain, so that they can be deleted easily
123 over calls to the inferior. Values assigned to internal variables,
124 put into the value history or exposed to Python are taken off this
125 list. */
127 struct value *value_next (const struct value *);
129 /* Type of the value. */
131 extern struct type *value_type (const struct value *);
133 /* Return the gdbarch associated with the value. */
135 extern struct gdbarch *get_value_arch (const struct value *value);
137 /* This is being used to change the type of an existing value, that
138 code should instead be creating a new value with the changed type
139 (but possibly shared content). */
141 extern void deprecated_set_value_type (struct value *value,
142 struct type *type);
144 /* Only used for bitfields; number of bits contained in them. */
146 extern LONGEST value_bitsize (const struct value *);
147 extern void set_value_bitsize (struct value *, LONGEST bit);
149 /* Only used for bitfields; position of start of field. For
150 little-endian targets, it is the position of the LSB. For
151 big-endian targets, it is the position of the MSB. */
153 extern LONGEST value_bitpos (const struct value *);
154 extern void set_value_bitpos (struct value *, LONGEST bit);
156 /* Only used for bitfields; the containing value. This allows a
157 single read from the target when displaying multiple
158 bitfields. */
160 struct value *value_parent (const struct value *);
161 extern void set_value_parent (struct value *value, struct value *parent);
163 /* Describes offset of a value within lval of a structure in bytes.
164 If lval == lval_memory, this is an offset to the address. If lval
165 == lval_register, this is a further offset from location.address
166 within the registers structure. Note also the member
167 embedded_offset below. */
169 extern LONGEST value_offset (const struct value *);
170 extern void set_value_offset (struct value *, LONGEST offset);
172 /* The comment from "struct value" reads: ``Is it modifiable? Only
173 relevant if lval != not_lval.''. Shouldn't the value instead be
174 not_lval and be done with it? */
176 extern int deprecated_value_modifiable (const struct value *value);
178 /* If a value represents a C++ object, then the `type' field gives the
179 object's compile-time type. If the object actually belongs to some
180 class derived from `type', perhaps with other base classes and
181 additional members, then `type' is just a subobject of the real
182 thing, and the full object is probably larger than `type' would
183 suggest.
185 If `type' is a dynamic class (i.e. one with a vtable), then GDB can
186 actually determine the object's run-time type by looking at the
187 run-time type information in the vtable. When this information is
188 available, we may elect to read in the entire object, for several
189 reasons:
191 - When printing the value, the user would probably rather see the
192 full object, not just the limited portion apparent from the
193 compile-time type.
195 - If `type' has virtual base classes, then even printing `type'
196 alone may require reaching outside the `type' portion of the
197 object to wherever the virtual base class has been stored.
199 When we store the entire object, `enclosing_type' is the run-time
200 type -- the complete object -- and `embedded_offset' is the offset
201 of `type' within that larger type, in bytes. The value_contents()
202 macro takes `embedded_offset' into account, so most GDB code
203 continues to see the `type' portion of the value, just as the
204 inferior would.
206 If `type' is a pointer to an object, then `enclosing_type' is a
207 pointer to the object's run-time type, and `pointed_to_offset' is
208 the offset in bytes from the full object to the pointed-to object
209 -- that is, the value `embedded_offset' would have if we followed
210 the pointer and fetched the complete object. (I don't really see
211 the point. Why not just determine the run-time type when you
212 indirect, and avoid the special case? The contents don't matter
213 until you indirect anyway.)
215 If we're not doing anything fancy, `enclosing_type' is equal to
216 `type', and `embedded_offset' is zero, so everything works
217 normally. */
219 extern struct type *value_enclosing_type (const struct value *);
220 extern void set_value_enclosing_type (struct value *val,
221 struct type *new_type);
223 /* Returns value_type or value_enclosing_type depending on
224 value_print_options.objectprint.
226 If RESOLVE_SIMPLE_TYPES is 0 the enclosing type will be resolved
227 only for pointers and references, else it will be returned
228 for all the types (e.g. structures). This option is useful
229 to prevent retrieving enclosing type for the base classes fields.
231 REAL_TYPE_FOUND is used to inform whether the real type was found
232 (or just static type was used). The NULL may be passed if it is not
233 necessary. */
235 extern struct type *value_actual_type (struct value *value,
236 int resolve_simple_types,
237 int *real_type_found);
239 extern LONGEST value_pointed_to_offset (const struct value *value);
240 extern void set_value_pointed_to_offset (struct value *value, LONGEST val);
241 extern LONGEST value_embedded_offset (const struct value *value);
242 extern void set_value_embedded_offset (struct value *value, LONGEST val);
244 /* For lval_computed values, this structure holds functions used to
245 retrieve and set the value (or portions of the value).
247 For each function, 'V' is the 'this' pointer: an lval_funcs
248 function F may always assume that the V it receives is an
249 lval_computed value, and has F in the appropriate slot of its
250 lval_funcs structure. */
252 struct lval_funcs
254 /* Fill in VALUE's contents. This is used to "un-lazy" values. If
255 a problem arises in obtaining VALUE's bits, this function should
256 call 'error'. If it is NULL value_fetch_lazy on "un-lazy"
257 non-optimized-out value is an internal error. */
258 void (*read) (struct value *v);
260 /* Handle an assignment TOVAL = FROMVAL by writing the value of
261 FROMVAL to TOVAL's location. The contents of TOVAL have not yet
262 been updated. If a problem arises in doing so, this function
263 should call 'error'. If it is NULL such TOVAL assignment is an error as
264 TOVAL is not considered as an lvalue. */
265 void (*write) (struct value *toval, struct value *fromval);
267 /* Return true if any part of V is optimized out, false otherwise.
268 This will only be called for lazy values -- if the value has been
269 fetched, then the value's optimized-out bits are consulted
270 instead. */
271 bool (*is_optimized_out) (struct value *v);
273 /* If non-NULL, this is used to implement pointer indirection for
274 this value. This method may return NULL, in which case value_ind
275 will fall back to ordinary indirection. */
276 struct value *(*indirect) (struct value *value);
278 /* If non-NULL, this is used to implement reference resolving for
279 this value. This method may return NULL, in which case coerce_ref
280 will fall back to ordinary references resolving. */
281 struct value *(*coerce_ref) (const struct value *value);
283 /* If non-NULL, this is used to determine whether the indicated bits
284 of VALUE are a synthetic pointer. */
285 int (*check_synthetic_pointer) (const struct value *value,
286 LONGEST offset, int length);
288 /* Return a duplicate of VALUE's closure, for use in a new value.
289 This may simply return the same closure, if VALUE's is
290 reference-counted or statically allocated.
292 This may be NULL, in which case VALUE's closure is re-used in the
293 new value. */
294 void *(*copy_closure) (const struct value *v);
296 /* Drop VALUE's reference to its closure. Maybe this frees the
297 closure; maybe this decrements a reference count; maybe the
298 closure is statically allocated and this does nothing.
300 This may be NULL, in which case no action is taken to free
301 VALUE's closure. */
302 void (*free_closure) (struct value *v);
305 /* Create a computed lvalue, with type TYPE, function pointers FUNCS,
306 and closure CLOSURE. */
308 extern struct value *allocate_computed_value (struct type *type,
309 const struct lval_funcs *funcs,
310 void *closure);
312 extern struct value *allocate_optimized_out_value (struct type *type);
314 /* If VALUE is lval_computed, return its lval_funcs structure. */
316 extern const struct lval_funcs *value_computed_funcs (const struct value *);
318 /* If VALUE is lval_computed, return its closure. The meaning of the
319 returned value depends on the functions VALUE uses. */
321 extern void *value_computed_closure (const struct value *value);
323 /* If zero, contents of this value are in the contents field. If
324 nonzero, contents are in inferior. If the lval field is lval_memory,
325 the contents are in inferior memory at location.address plus offset.
326 The lval field may also be lval_register.
328 WARNING: This field is used by the code which handles watchpoints
329 (see breakpoint.c) to decide whether a particular value can be
330 watched by hardware watchpoints. If the lazy flag is set for some
331 member of a value chain, it is assumed that this member of the
332 chain doesn't need to be watched as part of watching the value
333 itself. This is how GDB avoids watching the entire struct or array
334 when the user wants to watch a single struct member or array
335 element. If you ever change the way lazy flag is set and reset, be
336 sure to consider this use as well! */
338 extern int value_lazy (const struct value *);
339 extern void set_value_lazy (struct value *value, int val);
341 extern int value_stack (const struct value *);
342 extern void set_value_stack (struct value *value, int val);
344 /* Throw an error complaining that the value has been optimized
345 out. */
347 extern void error_value_optimized_out (void);
349 /* value_contents() and value_contents_raw() both return the address
350 of the gdb buffer used to hold a copy of the contents of the lval.
351 value_contents() is used when the contents of the buffer are needed
352 -- it uses value_fetch_lazy() to load the buffer from the process
353 being debugged if it hasn't already been loaded
354 (value_contents_writeable() is used when a writeable but fetched
355 buffer is required).. value_contents_raw() is used when data is
356 being stored into the buffer, or when it is certain that the
357 contents of the buffer are valid.
359 Note: The contents pointer is adjusted by the offset required to
360 get to the real subobject, if the value happens to represent
361 something embedded in a larger run-time object. */
363 extern gdb::array_view<gdb_byte> value_contents_raw (struct value *);
365 /* Actual contents of the value. For use of this value; setting it
366 uses the stuff above. Not valid if lazy is nonzero. Target
367 byte-order. We force it to be aligned properly for any possible
368 value. Note that a value therefore extends beyond what is
369 declared here. */
371 extern gdb::array_view<const gdb_byte> value_contents (struct value *);
372 extern gdb::array_view<gdb_byte> value_contents_writeable (struct value *);
374 /* The ALL variants of the above two macros do not adjust the returned
375 pointer by the embedded_offset value. */
377 extern gdb::array_view<gdb_byte> value_contents_all_raw (struct value *);
378 extern gdb::array_view<const gdb_byte> value_contents_all (struct value *);
380 /* Like value_contents_all, but does not require that the returned
381 bits be valid. This should only be used in situations where you
382 plan to check the validity manually. */
383 extern gdb::array_view<const gdb_byte> value_contents_for_printing (struct value *value);
385 /* Like value_contents_for_printing, but accepts a constant value
386 pointer. Unlike value_contents_for_printing however, the pointed
387 value must _not_ be lazy. */
388 extern gdb::array_view<const gdb_byte>
389 value_contents_for_printing_const (const struct value *value);
391 extern void value_fetch_lazy (struct value *val);
393 /* If nonzero, this is the value of a variable which does not actually
394 exist in the program, at least partially. If the value is lazy,
395 this may fetch it now. */
396 extern int value_optimized_out (struct value *value);
398 /* Given a value, return true if any of the contents bits starting at
399 OFFSET and extending for LENGTH bits is optimized out, false
400 otherwise. */
402 extern int value_bits_any_optimized_out (const struct value *value,
403 int bit_offset, int bit_length);
405 /* Like value_optimized_out, but return true iff the whole value is
406 optimized out. */
407 extern int value_entirely_optimized_out (struct value *value);
409 /* Mark VALUE's content bytes starting at OFFSET and extending for
410 LENGTH bytes as optimized out. */
412 extern void mark_value_bytes_optimized_out (struct value *value,
413 int offset, int length);
415 /* Mark VALUE's content bits starting at OFFSET and extending for
416 LENGTH bits as optimized out. */
418 extern void mark_value_bits_optimized_out (struct value *value,
419 LONGEST offset, LONGEST length);
421 /* Set or return field indicating whether a variable is initialized or
422 not, based on debugging information supplied by the compiler.
423 1 = initialized; 0 = uninitialized. */
424 extern int value_initialized (const struct value *);
425 extern void set_value_initialized (struct value *, int);
427 /* Set COMPONENT's location as appropriate for a component of WHOLE
428 --- regardless of what kind of lvalue WHOLE is. */
429 extern void set_value_component_location (struct value *component,
430 const struct value *whole);
432 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
433 single value might have multiple LVALs), this hacked interface is
434 limited to just the first PIECE. Expect further change. */
435 /* Type of value; either not an lval, or one of the various different
436 possible kinds of lval. */
437 extern enum lval_type *deprecated_value_lval_hack (struct value *);
438 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
440 /* Like VALUE_LVAL, except the parameter can be const. */
441 extern enum lval_type value_lval_const (const struct value *value);
443 /* If lval == lval_memory, return the address in the inferior. If
444 lval == lval_register, return the byte offset into the registers
445 structure. Otherwise, return 0. The returned address
446 includes the offset, if any. */
447 extern CORE_ADDR value_address (const struct value *);
449 /* Like value_address, except the result does not include value's
450 offset. */
451 extern CORE_ADDR value_raw_address (const struct value *);
453 /* Set the address of a value. */
454 extern void set_value_address (struct value *, CORE_ADDR);
456 /* Pointer to internal variable. */
457 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
458 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
460 /* Frame ID of "next" frame to which a register value is relative. A
461 register value is indicated by VALUE_LVAL being set to lval_register.
462 So, if the register value is found relative to frame F, then the
463 frame id of F->next will be stored in VALUE_NEXT_FRAME_ID. */
464 extern struct frame_id *deprecated_value_next_frame_id_hack (struct value *);
465 #define VALUE_NEXT_FRAME_ID(val) (*deprecated_value_next_frame_id_hack (val))
467 /* Register number if the value is from a register. */
468 extern int *deprecated_value_regnum_hack (struct value *);
469 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
471 /* Return value after lval_funcs->coerce_ref (after check_typedef). Return
472 NULL if lval_funcs->coerce_ref is not applicable for whatever reason. */
474 extern struct value *coerce_ref_if_computed (const struct value *arg);
476 /* Setup a new value type and enclosing value type for dereferenced value VALUE.
477 ENC_TYPE is the new enclosing type that should be set. ORIGINAL_TYPE and
478 ORIGINAL_VAL are the type and value of the original reference or
479 pointer. ORIGINAL_VALUE_ADDRESS is the address within VALUE, that is
480 the address that was dereferenced.
482 Note, that VALUE is modified by this function.
484 It is a common implementation for coerce_ref and value_ind. */
486 extern struct value * readjust_indirect_value_type (struct value *value,
487 struct type *enc_type,
488 const struct type *original_type,
489 struct value *original_val,
490 CORE_ADDR original_value_address);
492 /* Convert a REF to the object referenced. */
494 extern struct value *coerce_ref (struct value *value);
496 /* If ARG is an array, convert it to a pointer.
497 If ARG is a function, convert it to a function pointer.
499 References are dereferenced. */
501 extern struct value *coerce_array (struct value *value);
503 /* Given a value, determine whether the bits starting at OFFSET and
504 extending for LENGTH bits are a synthetic pointer. */
506 extern int value_bits_synthetic_pointer (const struct value *value,
507 LONGEST offset, LONGEST length);
509 /* Given a value, determine whether the contents bytes starting at
510 OFFSET and extending for LENGTH bytes are available. This returns
511 nonzero if all bytes in the given range are available, zero if any
512 byte is unavailable. */
514 extern int value_bytes_available (const struct value *value,
515 LONGEST offset, LONGEST length);
517 /* Given a value, determine whether the contents bits starting at
518 OFFSET and extending for LENGTH bits are available. This returns
519 nonzero if all bits in the given range are available, zero if any
520 bit is unavailable. */
522 extern int value_bits_available (const struct value *value,
523 LONGEST offset, LONGEST length);
525 /* Like value_bytes_available, but return false if any byte in the
526 whole object is unavailable. */
527 extern int value_entirely_available (struct value *value);
529 /* Like value_entirely_available, but return false if any byte in the
530 whole object is available. */
531 extern int value_entirely_unavailable (struct value *value);
533 /* Mark VALUE's content bytes starting at OFFSET and extending for
534 LENGTH bytes as unavailable. */
536 extern void mark_value_bytes_unavailable (struct value *value,
537 LONGEST offset, LONGEST length);
539 /* Mark VALUE's content bits starting at OFFSET and extending for
540 LENGTH bits as unavailable. */
542 extern void mark_value_bits_unavailable (struct value *value,
543 LONGEST offset, LONGEST length);
545 /* Compare LENGTH bytes of VAL1's contents starting at OFFSET1 with
546 LENGTH bytes of VAL2's contents starting at OFFSET2.
548 Note that "contents" refers to the whole value's contents
549 (value_contents_all), without any embedded offset adjustment. For
550 example, to compare a complete object value with itself, including
551 its enclosing type chunk, you'd do:
553 int len = TYPE_LENGTH (check_typedef (value_enclosing_type (val)));
554 value_contents_eq (val, 0, val, 0, len);
556 Returns true iff the set of available/valid contents match.
558 Optimized-out contents are equal to optimized-out contents, and are
559 not equal to non-optimized-out contents.
561 Unavailable contents are equal to unavailable contents, and are not
562 equal to non-unavailable contents.
564 For example, if 'x's represent an unavailable byte, and 'V' and 'Z'
565 represent different available/valid bytes, in a value with length
568 offset: 0 4 8 12 16
569 contents: xxxxVVVVxxxxVVZZ
571 then:
573 value_contents_eq(val, 0, val, 8, 6) => true
574 value_contents_eq(val, 0, val, 4, 4) => false
575 value_contents_eq(val, 0, val, 8, 8) => false
576 value_contents_eq(val, 4, val, 12, 2) => true
577 value_contents_eq(val, 4, val, 12, 4) => true
578 value_contents_eq(val, 3, val, 4, 4) => true
580 If 'x's represent an unavailable byte, 'o' represents an optimized
581 out byte, in a value with length 8:
583 offset: 0 4 8
584 contents: xxxxoooo
586 then:
588 value_contents_eq(val, 0, val, 2, 2) => true
589 value_contents_eq(val, 4, val, 6, 2) => true
590 value_contents_eq(val, 0, val, 4, 4) => true
592 We only know whether a value chunk is unavailable or optimized out
593 if we've tried to read it. As this routine is used by printing
594 routines, which may be printing values in the value history, long
595 after the inferior is gone, it works with const values. Therefore,
596 this routine must not be called with lazy values. */
598 extern bool value_contents_eq (const struct value *val1, LONGEST offset1,
599 const struct value *val2, LONGEST offset2,
600 LONGEST length);
602 /* Read LENGTH addressable memory units starting at MEMADDR into BUFFER,
603 which is (or will be copied to) VAL's contents buffer offset by
604 BIT_OFFSET bits. Marks value contents ranges as unavailable if
605 the corresponding memory is likewise unavailable. STACK indicates
606 whether the memory is known to be stack memory. */
608 extern void read_value_memory (struct value *val, LONGEST bit_offset,
609 int stack, CORE_ADDR memaddr,
610 gdb_byte *buffer, size_t length);
612 /* Cast SCALAR_VALUE to the element type of VECTOR_TYPE, then replicate
613 into each element of a new vector value with VECTOR_TYPE. */
615 struct value *value_vector_widen (struct value *scalar_value,
616 struct type *vector_type);
620 #include "symtab.h"
621 #include "gdbtypes.h"
622 #include "expression.h"
624 struct frame_info;
625 struct fn_field;
627 extern int print_address_demangle (const struct value_print_options *,
628 struct gdbarch *, CORE_ADDR,
629 struct ui_file *, int);
631 /* Returns true if VAL is of floating-point type. In addition,
632 throws an error if the value is an invalid floating-point value. */
633 extern bool is_floating_value (struct value *val);
635 extern LONGEST value_as_long (struct value *val);
636 extern CORE_ADDR value_as_address (struct value *val);
638 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
639 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
641 extern LONGEST unpack_field_as_long (struct type *type,
642 const gdb_byte *valaddr,
643 int fieldno);
645 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at
646 VALADDR, and store the result in *RESULT.
647 The bitfield starts at BITPOS bits and contains BITSIZE bits; if
648 BITSIZE is zero, then the length is taken from FIELD_TYPE.
650 Extracting bits depends on endianness of the machine. Compute the
651 number of least significant bits to discard. For big endian machines,
652 we compute the total number of bits in the anonymous object, subtract
653 off the bit count from the MSB of the object to the MSB of the
654 bitfield, then the size of the bitfield, which leaves the LSB discard
655 count. For little endian machines, the discard count is simply the
656 number of bits from the LSB of the anonymous object to the LSB of the
657 bitfield.
659 If the field is signed, we also do sign extension. */
661 extern LONGEST unpack_bits_as_long (struct type *field_type,
662 const gdb_byte *valaddr,
663 LONGEST bitpos, LONGEST bitsize);
665 extern int unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr,
666 LONGEST embedded_offset, int fieldno,
667 const struct value *val, LONGEST *result);
669 extern void unpack_value_bitfield (struct value *dest_val,
670 LONGEST bitpos, LONGEST bitsize,
671 const gdb_byte *valaddr,
672 LONGEST embedded_offset,
673 const struct value *val);
675 extern struct value *value_field_bitfield (struct type *type, int fieldno,
676 const gdb_byte *valaddr,
677 LONGEST embedded_offset,
678 const struct value *val);
680 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
682 extern struct value *value_from_longest (struct type *type, LONGEST num);
683 extern struct value *value_from_ulongest (struct type *type, ULONGEST num);
684 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
685 extern struct value *value_from_host_double (struct type *type, double d);
686 extern struct value *value_from_history_ref (const char *, const char **);
687 extern struct value *value_from_component (struct value *, struct type *,
688 LONGEST);
690 extern struct value *value_at (struct type *type, CORE_ADDR addr);
691 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
693 extern struct value *value_from_contents_and_address_unresolved
694 (struct type *, const gdb_byte *, CORE_ADDR);
695 extern struct value *value_from_contents_and_address (struct type *,
696 const gdb_byte *,
697 CORE_ADDR);
698 extern struct value *value_from_contents (struct type *, const gdb_byte *);
700 extern struct value *default_value_from_register (struct gdbarch *gdbarch,
701 struct type *type,
702 int regnum,
703 struct frame_id frame_id);
705 extern void read_frame_register_value (struct value *value,
706 struct frame_info *frame);
708 extern struct value *value_from_register (struct type *type, int regnum,
709 struct frame_info *frame);
711 extern CORE_ADDR address_from_register (int regnum,
712 struct frame_info *frame);
714 extern struct value *value_of_variable (struct symbol *var,
715 const struct block *b);
717 extern struct value *address_of_variable (struct symbol *var,
718 const struct block *b);
720 extern struct value *value_of_register (int regnum, struct frame_info *frame);
722 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
724 /* Return the symbol's reading requirement. */
726 extern enum symbol_needs_kind symbol_read_needs (struct symbol *);
728 /* Return true if the symbol needs a frame. This is a wrapper for
729 symbol_read_needs that simply checks for SYMBOL_NEEDS_FRAME. */
731 extern int symbol_read_needs_frame (struct symbol *);
733 extern struct value *read_var_value (struct symbol *var,
734 const struct block *var_block,
735 struct frame_info *frame);
737 extern struct value *allocate_value (struct type *type);
738 extern struct value *allocate_value_lazy (struct type *type);
739 extern void value_contents_copy (struct value *dst, LONGEST dst_offset,
740 struct value *src, LONGEST src_offset,
741 LONGEST length);
743 extern struct value *allocate_repeat_value (struct type *type, int count);
745 extern struct value *value_mark (void);
747 extern void value_free_to_mark (const struct value *mark);
749 /* A helper class that uses value_mark at construction time and calls
750 value_free_to_mark in the destructor. This is used to clear out
751 temporary values created during the lifetime of this object. */
752 class scoped_value_mark
754 public:
756 scoped_value_mark ()
757 : m_value (value_mark ())
761 ~scoped_value_mark ()
763 free_to_mark ();
766 scoped_value_mark (scoped_value_mark &&other) = default;
768 DISABLE_COPY_AND_ASSIGN (scoped_value_mark);
770 /* Free the values currently on the value stack. */
771 void free_to_mark ()
773 if (m_value != NULL)
775 value_free_to_mark (m_value);
776 m_value = NULL;
780 private:
782 const struct value *m_value;
785 extern struct value *value_cstring (const char *ptr, ssize_t len,
786 struct type *char_type);
787 extern struct value *value_string (const char *ptr, ssize_t len,
788 struct type *char_type);
790 extern struct value *value_array (int lowbound, int highbound,
791 struct value **elemvec);
793 extern struct value *value_concat (struct value *arg1, struct value *arg2);
795 extern struct value *value_binop (struct value *arg1, struct value *arg2,
796 enum exp_opcode op);
798 extern struct value *value_ptradd (struct value *arg1, LONGEST arg2);
800 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
802 /* Return true if VAL does not live in target memory, but should in order
803 to operate on it. Otherwise return false. */
805 extern bool value_must_coerce_to_target (struct value *arg1);
807 extern struct value *value_coerce_to_target (struct value *arg1);
809 extern struct value *value_coerce_array (struct value *arg1);
811 extern struct value *value_coerce_function (struct value *arg1);
813 extern struct value *value_ind (struct value *arg1);
815 extern struct value *value_addr (struct value *arg1);
817 extern struct value *value_ref (struct value *arg1, enum type_code refcode);
819 extern struct value *value_assign (struct value *toval,
820 struct value *fromval);
822 extern struct value *value_pos (struct value *arg1);
824 extern struct value *value_neg (struct value *arg1);
826 extern struct value *value_complement (struct value *arg1);
828 extern struct value *value_struct_elt (struct value **argp,
829 gdb::optional<gdb::array_view <value *>> args,
830 const char *name, int *static_memfuncp,
831 const char *err);
833 extern struct value *value_struct_elt_bitpos (struct value **argp,
834 int bitpos,
835 struct type *field_type,
836 const char *err);
838 extern struct value *value_aggregate_elt (struct type *curtype,
839 const char *name,
840 struct type *expect_type,
841 int want_address,
842 enum noside noside);
844 extern struct value *value_static_field (struct type *type, int fieldno);
846 enum oload_search_type { NON_METHOD, METHOD, BOTH };
848 extern int find_overload_match (gdb::array_view<value *> args,
849 const char *name,
850 enum oload_search_type method,
851 struct value **objp, struct symbol *fsym,
852 struct value **valp, struct symbol **symp,
853 int *staticp, const int no_adl,
854 enum noside noside);
856 extern struct value *value_field (struct value *arg1, int fieldno);
858 extern struct value *value_primitive_field (struct value *arg1, LONGEST offset,
859 int fieldno,
860 struct type *arg_type);
863 extern struct type *value_rtti_indirect_type (struct value *, int *, LONGEST *,
864 int *);
866 extern struct value *value_full_object (struct value *, struct type *, int,
867 int, int);
869 extern struct value *value_cast_pointers (struct type *, struct value *, int);
871 extern struct value *value_cast (struct type *type, struct value *arg2);
873 extern struct value *value_reinterpret_cast (struct type *type,
874 struct value *arg);
876 extern struct value *value_dynamic_cast (struct type *type, struct value *arg);
878 extern struct value *value_zero (struct type *type, enum lval_type lv);
880 extern struct value *value_one (struct type *type);
882 extern struct value *value_repeat (struct value *arg1, int count);
884 extern struct value *value_subscript (struct value *array, LONGEST index);
886 extern struct value *value_bitstring_subscript (struct type *type,
887 struct value *bitstring,
888 LONGEST index);
890 extern struct value *register_value_being_returned (struct type *valtype,
891 struct regcache *retbuf);
893 extern int value_in (struct value *element, struct value *set);
895 extern int value_bit_index (struct type *type, const gdb_byte *addr,
896 int index);
898 extern enum return_value_convention
899 struct_return_convention (struct gdbarch *gdbarch, struct value *function,
900 struct type *value_type);
902 extern int using_struct_return (struct gdbarch *gdbarch,
903 struct value *function,
904 struct type *value_type);
906 /* Evaluate the expression EXP. If set, EXPECT_TYPE is passed to the
907 outermost operation's evaluation. This is ignored by most
908 operations, but may be used, e.g., to determine the type of an
909 otherwise untyped symbol. The caller should not assume that the
910 returned value has this type. */
912 extern struct value *evaluate_expression (struct expression *exp,
913 struct type *expect_type = nullptr);
915 extern struct value *evaluate_type (struct expression *exp);
917 extern value *evaluate_var_value (enum noside noside, const block *blk,
918 symbol *var);
920 extern value *evaluate_var_msym_value (enum noside noside,
921 struct objfile *objfile,
922 minimal_symbol *msymbol);
924 namespace expr { class operation; };
925 extern void fetch_subexp_value (struct expression *exp,
926 expr::operation *op,
927 struct value **valp, struct value **resultp,
928 std::vector<value_ref_ptr> *val_chain,
929 bool preserve_errors);
931 extern struct value *parse_and_eval (const char *exp);
933 extern struct value *parse_to_comma_and_eval (const char **expp);
935 extern struct type *parse_and_eval_type (const char *p, int length);
937 extern CORE_ADDR parse_and_eval_address (const char *exp);
939 extern LONGEST parse_and_eval_long (const char *exp);
941 extern void unop_promote (const struct language_defn *language,
942 struct gdbarch *gdbarch,
943 struct value **arg1);
945 extern void binop_promote (const struct language_defn *language,
946 struct gdbarch *gdbarch,
947 struct value **arg1, struct value **arg2);
949 extern struct value *access_value_history (int num);
951 /* Return the number of items in the value history. */
953 extern ULONGEST value_history_count ();
955 extern struct value *value_of_internalvar (struct gdbarch *gdbarch,
956 struct internalvar *var);
958 extern int get_internalvar_integer (struct internalvar *var, LONGEST *l);
960 extern void set_internalvar (struct internalvar *var, struct value *val);
962 extern void set_internalvar_integer (struct internalvar *var, LONGEST l);
964 extern void set_internalvar_string (struct internalvar *var,
965 const char *string);
967 extern void clear_internalvar (struct internalvar *var);
969 extern void set_internalvar_component (struct internalvar *var,
970 LONGEST offset,
971 LONGEST bitpos, LONGEST bitsize,
972 struct value *newvalue);
974 extern struct internalvar *lookup_only_internalvar (const char *name);
976 extern struct internalvar *create_internalvar (const char *name);
978 extern void complete_internalvar (completion_tracker &tracker,
979 const char *name);
981 /* An internalvar can be dynamically computed by supplying a vector of
982 function pointers to perform various operations. */
984 struct internalvar_funcs
986 /* Compute the value of the variable. The DATA argument passed to
987 the function is the same argument that was passed to
988 `create_internalvar_type_lazy'. */
990 struct value *(*make_value) (struct gdbarch *arch,
991 struct internalvar *var,
992 void *data);
994 /* Update the agent expression EXPR with bytecode to compute the
995 value. VALUE is the agent value we are updating. The DATA
996 argument passed to this function is the same argument that was
997 passed to `create_internalvar_type_lazy'. If this pointer is
998 NULL, then the internalvar cannot be compiled to an agent
999 expression. */
1001 void (*compile_to_ax) (struct internalvar *var,
1002 struct agent_expr *expr,
1003 struct axs_value *value,
1004 void *data);
1007 extern struct internalvar *create_internalvar_type_lazy (const char *name,
1008 const struct internalvar_funcs *funcs,
1009 void *data);
1011 /* Compile an internal variable to an agent expression. VAR is the
1012 variable to compile; EXPR and VALUE are the agent expression we are
1013 updating. This will return 0 if there is no known way to compile
1014 VAR, and 1 if VAR was successfully compiled. It may also throw an
1015 exception on error. */
1017 extern int compile_internalvar_to_ax (struct internalvar *var,
1018 struct agent_expr *expr,
1019 struct axs_value *value);
1021 extern struct internalvar *lookup_internalvar (const char *name);
1023 extern int value_equal (struct value *arg1, struct value *arg2);
1025 extern int value_equal_contents (struct value *arg1, struct value *arg2);
1027 extern int value_less (struct value *arg1, struct value *arg2);
1029 /* Simulate the C operator ! -- return true if ARG1 contains zero. */
1030 extern bool value_logical_not (struct value *arg1);
1032 /* Returns true if the value VAL represents a true value. */
1033 static inline bool
1034 value_true (struct value *val)
1036 return !value_logical_not (val);
1039 /* C++ */
1041 extern struct value *value_of_this (const struct language_defn *lang);
1043 extern struct value *value_of_this_silent (const struct language_defn *lang);
1045 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
1046 enum exp_opcode op,
1047 enum exp_opcode otherop,
1048 enum noside noside);
1050 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
1051 enum noside noside);
1053 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
1054 int j, struct type *type, LONGEST offset);
1056 extern int binop_types_user_defined_p (enum exp_opcode op,
1057 struct type *type1,
1058 struct type *type2);
1060 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
1061 struct value *arg2);
1063 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
1065 extern int destructor_name_p (const char *name, struct type *type);
1067 extern value_ref_ptr release_value (struct value *val);
1069 extern int record_latest_value (struct value *val);
1071 extern void modify_field (struct type *type, gdb_byte *addr,
1072 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize);
1074 extern void type_print (struct type *type, const char *varstring,
1075 struct ui_file *stream, int show);
1077 extern std::string type_to_string (struct type *type);
1079 extern gdb_byte *baseclass_addr (struct type *type, int index,
1080 gdb_byte *valaddr,
1081 struct value **valuep, int *errp);
1083 extern void print_longest (struct ui_file *stream, int format,
1084 int use_local, LONGEST val);
1086 extern void print_floating (const gdb_byte *valaddr, struct type *type,
1087 struct ui_file *stream);
1089 extern void value_print (struct value *val, struct ui_file *stream,
1090 const struct value_print_options *options);
1092 /* Release values from the value chain and return them. Values
1093 created after MARK are released. If MARK is nullptr, or if MARK is
1094 not found on the value chain, then all values are released. Values
1095 are returned in reverse order of creation; that is, newest
1096 first. */
1098 extern std::vector<value_ref_ptr> value_release_to_mark
1099 (const struct value *mark);
1101 extern void common_val_print (struct value *val,
1102 struct ui_file *stream, int recurse,
1103 const struct value_print_options *options,
1104 const struct language_defn *language);
1106 extern int val_print_string (struct type *elttype, const char *encoding,
1107 CORE_ADDR addr, int len,
1108 struct ui_file *stream,
1109 const struct value_print_options *options);
1111 extern void print_variable_and_value (const char *name,
1112 struct symbol *var,
1113 struct frame_info *frame,
1114 struct ui_file *stream,
1115 int indent);
1117 extern void typedef_print (struct type *type, struct symbol *news,
1118 struct ui_file *stream);
1120 extern const char *internalvar_name (const struct internalvar *var);
1122 extern void preserve_values (struct objfile *);
1124 /* From values.c */
1126 extern struct value *value_copy (const value *);
1128 extern struct value *value_non_lval (struct value *);
1130 extern void value_force_lval (struct value *, CORE_ADDR);
1132 extern struct value *make_cv_value (int, int, struct value *);
1134 extern void preserve_one_value (struct value *, struct objfile *, htab_t);
1136 /* From valops.c */
1138 extern struct value *varying_to_slice (struct value *);
1140 extern struct value *value_slice (struct value *, int, int);
1142 /* Create a complex number. The type is the complex type; the values
1143 are cast to the underlying scalar type before the complex number is
1144 created. */
1146 extern struct value *value_literal_complex (struct value *, struct value *,
1147 struct type *);
1149 /* Return the real part of a complex value. */
1151 extern struct value *value_real_part (struct value *value);
1153 /* Return the imaginary part of a complex value. */
1155 extern struct value *value_imaginary_part (struct value *value);
1157 extern struct value *find_function_in_inferior (const char *,
1158 struct objfile **);
1160 extern struct value *value_allocate_space_in_inferior (int);
1162 /* User function handler. */
1164 typedef struct value *(*internal_function_fn) (struct gdbarch *gdbarch,
1165 const struct language_defn *language,
1166 void *cookie,
1167 int argc,
1168 struct value **argv);
1170 /* Add a new internal function. NAME is the name of the function; DOC
1171 is a documentation string describing the function. HANDLER is
1172 called when the function is invoked. COOKIE is an arbitrary
1173 pointer which is passed to HANDLER and is intended for "user
1174 data". */
1176 extern void add_internal_function (const char *name, const char *doc,
1177 internal_function_fn handler,
1178 void *cookie);
1180 /* This overload takes an allocated documentation string. */
1182 extern void add_internal_function (gdb::unique_xmalloc_ptr<char> &&name,
1183 gdb::unique_xmalloc_ptr<char> &&doc,
1184 internal_function_fn handler,
1185 void *cookie);
1187 struct value *call_internal_function (struct gdbarch *gdbarch,
1188 const struct language_defn *language,
1189 struct value *function,
1190 int argc, struct value **argv);
1192 const char *value_internal_function_name (struct value *);
1194 /* Build a value wrapping and representing WORKER. The value takes ownership
1195 of the xmethod_worker object. */
1197 extern struct value *value_from_xmethod (xmethod_worker_up &&worker);
1199 extern struct type *result_type_of_xmethod (struct value *method,
1200 gdb::array_view<value *> argv);
1202 extern struct value *call_xmethod (struct value *method,
1203 gdb::array_view<value *> argv);
1205 /* Destroy the values currently allocated. This is called when GDB is
1206 exiting (e.g., on quit_force). */
1207 extern void finalize_values ();
1209 /* Convert VALUE to a gdb_mpq. The caller must ensure that VALUE is
1210 of floating-point, fixed-point, or integer type. */
1211 extern gdb_mpq value_to_gdb_mpq (struct value *value);
1213 #endif /* !defined (VALUE_H) */