0c8522382d95ca4404f21e6973e7b01066fed520
[deliverable/binutils-gdb.git] / gdb / value.h
1 /* Definitions for values of C expressions, for GDB.
2
3 Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
4 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
5 2008, 2009 Free Software Foundation, Inc.
6
7 This file is part of GDB.
8
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 3 of the License, or
12 (at your option) any later version.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program. If not, see <http://www.gnu.org/licenses/>. */
21
22 #if !defined (VALUE_H)
23 #define VALUE_H 1
24
25 #include "doublest.h"
26 #include "frame.h" /* For struct frame_id. */
27
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;
36
37 /* The structure which defines the type of a value. It should never
38 be possible for a program lval value to survive over a call to the
39 inferior (i.e. to be put into the history list or an internal
40 variable). */
41
42 struct value;
43
44 /* Needed if another module needs to maintain its own list of values. */
45
46 void value_prepend_to_list (struct value **head, struct value *val);
47 void value_remove_from_list (struct value **head, struct value *val);
48
49 /* Values are stored in a chain, so that they can be deleted easily
50 over calls to the inferior. Values assigned to internal variables,
51 put into the value history or exposed to Python are taken off this
52 list. */
53
54 struct value *value_next (struct value *);
55
56 /* Type of the value. */
57
58 extern struct type *value_type (struct value *);
59
60 /* This is being used to change the type of an existing value, that
61 code should instead be creating a new value with the changed type
62 (but possibly shared content). */
63
64 extern void deprecated_set_value_type (struct value *value,
65 struct type *type);
66
67 /* Only used for bitfields; number of bits contained in them. */
68
69 extern int value_bitsize (struct value *);
70 extern void set_value_bitsize (struct value *, int bit);
71
72 /* Only used for bitfields; position of start of field. For
73 gdbarch_bits_big_endian=0 targets, it is the position of the LSB. For
74 gdbarch_bits_big_endian=1 targets, it is the position of the MSB. */
75
76 extern int value_bitpos (struct value *);
77 extern void set_value_bitpos (struct value *, int bit);
78
79 /* Describes offset of a value within lval of a structure in bytes.
80 If lval == lval_memory, this is an offset to the address. If lval
81 == lval_register, this is a further offset from location.address
82 within the registers structure. Note also the member
83 embedded_offset below. */
84
85 extern int value_offset (struct value *);
86 extern void set_value_offset (struct value *, int offset);
87
88 /* The comment from "struct value" reads: ``Is it modifiable? Only
89 relevant if lval != not_lval.''. Shouldn't the value instead be
90 not_lval and be done with it? */
91
92 extern int deprecated_value_modifiable (struct value *value);
93 extern void deprecated_set_value_modifiable (struct value *value,
94 int modifiable);
95
96 /* If a value represents a C++ object, then the `type' field gives the
97 object's compile-time type. If the object actually belongs to some
98 class derived from `type', perhaps with other base classes and
99 additional members, then `type' is just a subobject of the real
100 thing, and the full object is probably larger than `type' would
101 suggest.
102
103 If `type' is a dynamic class (i.e. one with a vtable), then GDB can
104 actually determine the object's run-time type by looking at the
105 run-time type information in the vtable. When this information is
106 available, we may elect to read in the entire object, for several
107 reasons:
108
109 - When printing the value, the user would probably rather see the
110 full object, not just the limited portion apparent from the
111 compile-time type.
112
113 - If `type' has virtual base classes, then even printing `type'
114 alone may require reaching outside the `type' portion of the
115 object to wherever the virtual base class has been stored.
116
117 When we store the entire object, `enclosing_type' is the run-time
118 type -- the complete object -- and `embedded_offset' is the offset
119 of `type' within that larger type, in bytes. The value_contents()
120 macro takes `embedded_offset' into account, so most GDB code
121 continues to see the `type' portion of the value, just as the
122 inferior would.
123
124 If `type' is a pointer to an object, then `enclosing_type' is a
125 pointer to the object's run-time type, and `pointed_to_offset' is
126 the offset in bytes from the full object to the pointed-to object
127 -- that is, the value `embedded_offset' would have if we followed
128 the pointer and fetched the complete object. (I don't really see
129 the point. Why not just determine the run-time type when you
130 indirect, and avoid the special case? The contents don't matter
131 until you indirect anyway.)
132
133 If we're not doing anything fancy, `enclosing_type' is equal to
134 `type', and `embedded_offset' is zero, so everything works
135 normally. */
136
137 extern struct type *value_enclosing_type (struct value *);
138 extern struct value *value_change_enclosing_type (struct value *val,
139 struct type *new_type);
140 extern int value_pointed_to_offset (struct value *value);
141 extern void set_value_pointed_to_offset (struct value *value, int val);
142 extern int value_embedded_offset (struct value *value);
143 extern void set_value_embedded_offset (struct value *value, int val);
144
145 /* For lval_computed values, this structure holds functions used to
146 retrieve and set the value (or portions of the value).
147
148 For each function, 'V' is the 'this' pointer: an lval_funcs
149 function F may always assume that the V it receives is an
150 lval_computed value, and has F in the appropriate slot of its
151 lval_funcs structure. */
152
153 struct lval_funcs
154 {
155 /* Fill in VALUE's contents. This is used to "un-lazy" values. If
156 a problem arises in obtaining VALUE's bits, this function should
157 call 'error'. */
158 void (*read) (struct value *v);
159
160 /* Handle an assignment TOVAL = FROMVAL by writing the value of
161 FROMVAL to TOVAL's location. The contents of TOVAL have not yet
162 been updated. If a problem arises in doing so, this function
163 should call 'error'. */
164 void (*write) (struct value *toval, struct value *fromval);
165
166 /* Return a duplicate of VALUE's closure, for use in a new value.
167 This may simply return the same closure, if VALUE's is
168 reference-counted or statically allocated.
169
170 This may be NULL, in which case VALUE's closure is re-used in the
171 new value. */
172 void *(*copy_closure) (struct value *v);
173
174 /* Drop VALUE's reference to its closure. Maybe this frees the
175 closure; maybe this decrements a reference count; maybe the
176 closure is statically allocated and this does nothing.
177
178 This may be NULL, in which case no action is taken to free
179 VALUE's closure. */
180 void (*free_closure) (struct value *v);
181 };
182
183 /* Create a computed lvalue, with type TYPE, function pointers FUNCS,
184 and closure CLOSURE. */
185
186 extern struct value *allocate_computed_value (struct type *type,
187 struct lval_funcs *funcs,
188 void *closure);
189
190 /* If VALUE is lval_computed, return its lval_funcs structure. */
191
192 extern struct lval_funcs *value_computed_funcs (struct value *value);
193
194 /* If VALUE is lval_computed, return its closure. The meaning of the
195 returned value depends on the functions VALUE uses. */
196
197 extern void *value_computed_closure (struct value *value);
198
199 /* If zero, contents of this value are in the contents field. If
200 nonzero, contents are in inferior. If the lval field is lval_memory,
201 the contents are in inferior memory at location.address plus offset.
202 The lval field may also be lval_register.
203
204 WARNING: This field is used by the code which handles watchpoints
205 (see breakpoint.c) to decide whether a particular value can be
206 watched by hardware watchpoints. If the lazy flag is set for some
207 member of a value chain, it is assumed that this member of the
208 chain doesn't need to be watched as part of watching the value
209 itself. This is how GDB avoids watching the entire struct or array
210 when the user wants to watch a single struct member or array
211 element. If you ever change the way lazy flag is set and reset, be
212 sure to consider this use as well! */
213
214 extern int value_lazy (struct value *);
215 extern void set_value_lazy (struct value *value, int val);
216
217 /* value_contents() and value_contents_raw() both return the address
218 of the gdb buffer used to hold a copy of the contents of the lval.
219 value_contents() is used when the contents of the buffer are needed
220 -- it uses value_fetch_lazy() to load the buffer from the process
221 being debugged if it hasn't already been loaded
222 (value_contents_writeable() is used when a writeable but fetched
223 buffer is required).. value_contents_raw() is used when data is
224 being stored into the buffer, or when it is certain that the
225 contents of the buffer are valid.
226
227 Note: The contents pointer is adjusted by the offset required to
228 get to the real subobject, if the value happens to represent
229 something embedded in a larger run-time object. */
230
231 extern gdb_byte *value_contents_raw (struct value *);
232
233 /* Actual contents of the value. For use of this value; setting it
234 uses the stuff above. Not valid if lazy is nonzero. Target
235 byte-order. We force it to be aligned properly for any possible
236 value. Note that a value therefore extends beyond what is
237 declared here. */
238
239 extern const gdb_byte *value_contents (struct value *);
240 extern gdb_byte *value_contents_writeable (struct value *);
241
242 /* The ALL variants of the above two macros do not adjust the returned
243 pointer by the embedded_offset value. */
244
245 extern gdb_byte *value_contents_all_raw (struct value *);
246 extern const gdb_byte *value_contents_all (struct value *);
247
248 extern int value_fetch_lazy (struct value *val);
249 extern int value_contents_equal (struct value *val1, struct value *val2);
250
251 /* If nonzero, this is the value of a variable which does not actually
252 exist in the program. */
253 extern int value_optimized_out (struct value *value);
254 extern void set_value_optimized_out (struct value *value, int val);
255
256 /* Set or return field indicating whether a variable is initialized or
257 not, based on debugging information supplied by the compiler.
258 1 = initialized; 0 = uninitialized. */
259 extern int value_initialized (struct value *);
260 extern void set_value_initialized (struct value *, int);
261
262 /* Set COMPONENT's location as appropriate for a component of WHOLE
263 --- regardless of what kind of lvalue WHOLE is. */
264 extern void set_value_component_location (struct value *component,
265 struct value *whole);
266
267 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
268 single value might have multiple LVALs), this hacked interface is
269 limited to just the first PIECE. Expect further change. */
270 /* Type of value; either not an lval, or one of the various different
271 possible kinds of lval. */
272 extern enum lval_type *deprecated_value_lval_hack (struct value *);
273 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
274
275 /* If lval == lval_memory, this is the address in the inferior. If
276 lval == lval_register, this is the byte offset into the registers
277 structure. */
278 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
279 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
280
281 /* Pointer to internal variable. */
282 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
283 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
284
285 /* Frame register value is relative to. This will be described in the
286 lval enum above as "lval_register". */
287 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
288 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
289
290 /* Register number if the value is from a register. */
291 extern short *deprecated_value_regnum_hack (struct value *);
292 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
293
294 /* Convert a REF to the object referenced. */
295
296 extern struct value *coerce_ref (struct value *value);
297
298 /* If ARG is an array, convert it to a pointer.
299 If ARG is a function, convert it to a function pointer.
300
301 References are dereferenced. */
302
303 extern struct value *coerce_array (struct value *value);
304
305 /* Internal variables (variables for convenience of use of debugger)
306 are recorded as a chain of these structures. */
307
308 struct internalvar
309 {
310 struct internalvar *next;
311 char *name;
312 struct value *value;
313 int endian;
314 };
315
316 \f
317
318 #include "symtab.h"
319 #include "gdbtypes.h"
320 #include "expression.h"
321
322 struct frame_info;
323 struct fn_field;
324
325 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
326
327 extern LONGEST value_as_long (struct value *val);
328 extern DOUBLEST value_as_double (struct value *val);
329 extern CORE_ADDR value_as_address (struct value *val);
330
331 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
332 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
333 int *invp);
334 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
335 extern LONGEST unpack_field_as_long (struct type *type,
336 const gdb_byte *valaddr,
337 int fieldno);
338
339 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
340
341 extern struct value *value_from_longest (struct type *type, LONGEST num);
342 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
343 extern struct value *value_from_double (struct type *type, DOUBLEST num);
344 extern struct value *value_from_decfloat (struct type *type,
345 const gdb_byte *decbytes);
346 extern struct value *value_from_string (char *string);
347
348 extern struct value *value_at (struct type *type, CORE_ADDR addr);
349 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
350
351 extern struct value *value_from_contents_and_address (struct type *,
352 const gdb_byte *,
353 CORE_ADDR);
354
355 extern struct value *default_value_from_register (struct type *type,
356 int regnum,
357 struct frame_info *frame);
358
359 extern struct value *value_from_register (struct type *type, int regnum,
360 struct frame_info *frame);
361
362 extern CORE_ADDR address_from_register (struct type *type, int regnum,
363 struct frame_info *frame);
364
365 extern struct value *value_of_variable (struct symbol *var, struct block *b);
366
367 extern struct value *address_of_variable (struct symbol *var, struct block *b);
368
369 extern struct value *value_of_register (int regnum, struct frame_info *frame);
370
371 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
372
373 extern int symbol_read_needs_frame (struct symbol *);
374
375 extern struct value *read_var_value (struct symbol *var,
376 struct frame_info *frame);
377
378 extern struct value *allocate_value (struct type *type);
379 extern struct value *allocate_value_lazy (struct type *type);
380 extern void allocate_value_contents (struct value *value);
381
382 extern struct value *allocate_repeat_value (struct type *type, int count);
383
384 extern struct value *value_mark (void);
385
386 extern void value_free_to_mark (struct value *mark);
387
388 extern struct value *value_string (char *ptr, int len);
389 extern struct value *value_bitstring (char *ptr, int len);
390
391 extern struct value *value_array (int lowbound, int highbound,
392 struct value **elemvec);
393
394 extern struct value *value_concat (struct value *arg1, struct value *arg2);
395
396 extern struct value *value_binop (struct value *arg1, struct value *arg2,
397 enum exp_opcode op);
398
399 extern struct value *value_ptradd (struct value *arg1, struct value *arg2);
400
401 extern struct value *value_ptrsub (struct value *arg1, struct value *arg2);
402
403 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
404
405 extern int value_must_coerce_to_target (struct value *arg1);
406
407 extern struct value *value_coerce_to_target (struct value *arg1);
408
409 extern struct value *value_coerce_array (struct value *arg1);
410
411 extern struct value *value_coerce_function (struct value *arg1);
412
413 extern struct value *value_ind (struct value *arg1);
414
415 extern struct value *value_addr (struct value *arg1);
416
417 extern struct value *value_ref (struct value *arg1);
418
419 extern struct value *value_assign (struct value *toval,
420 struct value *fromval);
421
422 extern struct value *value_pos (struct value *arg1);
423
424 extern struct value *value_neg (struct value *arg1);
425
426 extern struct value *value_complement (struct value *arg1);
427
428 extern struct value *value_struct_elt (struct value **argp,
429 struct value **args,
430 char *name, int *static_memfuncp,
431 char *err);
432
433 extern struct value *value_aggregate_elt (struct type *curtype,
434 char *name,
435 int want_address,
436 enum noside noside);
437
438 extern struct value *value_static_field (struct type *type, int fieldno);
439
440 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
441 int, int *,
442 struct type **, int *);
443
444 extern int find_overload_match (struct type **arg_types, int nargs,
445 char *name, int method, int lax,
446 struct value **objp, struct symbol *fsym,
447 struct value **valp, struct symbol **symp,
448 int *staticp);
449
450 extern struct value *value_field (struct value *arg1, int fieldno);
451
452 extern struct value *value_primitive_field (struct value *arg1, int offset,
453 int fieldno,
454 struct type *arg_type);
455
456
457 extern struct type *value_rtti_target_type (struct value *, int *, int *,
458 int *);
459
460 extern struct value *value_full_object (struct value *, struct type *, int,
461 int, int);
462
463 extern struct value *value_cast_pointers (struct type *, struct value *);
464
465 extern struct value *value_cast (struct type *type, struct value *arg2);
466
467 extern struct value *value_zero (struct type *type, enum lval_type lv);
468
469 extern struct value *value_one (struct type *type, enum lval_type lv);
470
471 extern struct value *value_repeat (struct value *arg1, int count);
472
473 extern struct value *value_subscript (struct value *array, struct value *idx);
474
475 extern struct value *value_bitstring_subscript (struct type *type,
476 struct value *bitstring,
477 struct value *idx);
478
479 extern struct value *register_value_being_returned (struct type *valtype,
480 struct regcache *retbuf);
481
482 extern int value_in (struct value *element, struct value *set);
483
484 extern int value_bit_index (struct type *type, const gdb_byte *addr,
485 int index);
486
487 extern int using_struct_return (struct type *func_type,
488 struct type *value_type);
489
490 extern struct value *evaluate_expression (struct expression *exp);
491
492 extern struct value *evaluate_type (struct expression *exp);
493
494 extern struct value *evaluate_subexpression_type (struct expression *exp,
495 int subexp);
496
497 extern char *extract_field_op (struct expression *exp, int *subexp);
498
499 extern struct value *evaluate_subexp_with_coercion (struct expression *,
500 int *, enum noside);
501
502 extern struct value *parse_and_eval (char *exp);
503
504 extern struct value *parse_to_comma_and_eval (char **expp);
505
506 extern struct type *parse_and_eval_type (char *p, int length);
507
508 extern CORE_ADDR parse_and_eval_address (char *exp);
509
510 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
511
512 extern LONGEST parse_and_eval_long (char *exp);
513
514 extern void unop_promote (const struct language_defn *language,
515 struct gdbarch *gdbarch,
516 struct value **arg1);
517
518 extern void binop_promote (const struct language_defn *language,
519 struct gdbarch *gdbarch,
520 struct value **arg1, struct value **arg2);
521
522 extern struct value *access_value_history (int num);
523
524 extern struct value *value_of_internalvar (struct internalvar *var);
525
526 extern void set_internalvar (struct internalvar *var, struct value *val);
527
528 extern void set_internalvar_component (struct internalvar *var,
529 int offset,
530 int bitpos, int bitsize,
531 struct value *newvalue);
532
533 extern struct internalvar *lookup_only_internalvar (char *name);
534
535 extern struct internalvar *create_internalvar (char *name);
536
537 extern struct internalvar *lookup_internalvar (char *name);
538
539 extern int value_equal (struct value *arg1, struct value *arg2);
540
541 extern int value_less (struct value *arg1, struct value *arg2);
542
543 extern int value_logical_not (struct value *arg1);
544
545 /* C++ */
546
547 extern struct value *value_of_this (int complain);
548
549 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
550 enum exp_opcode op,
551 enum exp_opcode otherop,
552 enum noside noside);
553
554 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
555 enum noside noside);
556
557 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
558 int j, struct type *type, int offset);
559
560 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
561 struct value *arg2);
562
563 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
564
565 extern int destructor_name_p (const char *name, const struct type *type);
566
567 extern void value_free (struct value *val);
568
569 extern void free_all_values (void);
570
571 extern void release_value (struct value *val);
572
573 extern int record_latest_value (struct value *val);
574
575 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
576 int bitsize);
577
578 extern void type_print (struct type *type, char *varstring,
579 struct ui_file *stream, int show);
580
581 extern char *type_to_string (struct type *type);
582
583 extern gdb_byte *baseclass_addr (struct type *type, int index,
584 gdb_byte *valaddr,
585 struct value **valuep, int *errp);
586
587 extern void print_longest (struct ui_file *stream, int format,
588 int use_local, LONGEST val);
589
590 extern void print_floating (const gdb_byte *valaddr, struct type *type,
591 struct ui_file *stream);
592
593 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
594 struct ui_file *stream);
595
596 extern int value_print (struct value *val, struct ui_file *stream,
597 const struct value_print_options *options);
598
599 extern void value_print_array_elements (struct value *val,
600 struct ui_file *stream, int format,
601 enum val_prettyprint pretty);
602
603 extern struct value *value_release_to_mark (struct value *mark);
604
605 extern int val_print (struct type *type, const gdb_byte *valaddr,
606 int embedded_offset, CORE_ADDR address,
607 struct ui_file *stream, int recurse,
608 const struct value_print_options *options,
609 const struct language_defn *language);
610
611 extern int common_val_print (struct value *val,
612 struct ui_file *stream, int recurse,
613 const struct value_print_options *options,
614 const struct language_defn *language);
615
616 extern int val_print_string (CORE_ADDR addr, int len, int width,
617 struct ui_file *stream,
618 const struct value_print_options *options);
619
620 extern void print_variable_and_value (const char *name,
621 struct symbol *var,
622 struct frame_info *frame,
623 struct ui_file *stream,
624 int indent);
625
626 extern int check_field (struct type *, const char *);
627
628 extern void typedef_print (struct type *type, struct symbol *news,
629 struct ui_file *stream);
630
631 extern char *internalvar_name (struct internalvar *var);
632
633 extern void preserve_values (struct objfile *);
634
635 /* From values.c */
636
637 extern struct value *value_copy (struct value *);
638
639 /* From valops.c */
640
641 extern struct value *varying_to_slice (struct value *);
642
643 extern struct value *value_slice (struct value *, int, int);
644
645 extern struct value *value_literal_complex (struct value *, struct value *,
646 struct type *);
647
648 extern struct value *find_function_in_inferior (const char *,
649 struct objfile **);
650
651 extern struct value *value_allocate_space_in_inferior (int);
652
653 extern struct value *value_of_local (const char *name, int complain);
654
655 extern struct value * value_subscripted_rvalue (struct value *array, struct value *idx, int lowerbound);
656 #endif /* !defined (VALUE_H) */
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