2009-02-06 Pedro Alves <pedro@codesourcery.com>
[binutils-gdb.git] / gdb / value.h
blobaa43365efe575b316515b26a63ce71e20f7a9e50
1 /* Definitions for values of C expressions, for GDB.
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.
7 This file is part of GDB.
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.
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.
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/>. */
22 #if !defined (VALUE_H)
23 #define VALUE_H 1
25 #include "doublest.h"
26 #include "frame.h" /* For struct frame_id. */
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 /* 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). */
42 struct value;
44 /* Needed if another module needs to maintain its own list of values. */
46 void value_prepend_to_list (struct value **head, struct value *val);
47 void value_remove_from_list (struct value **head, struct value *val);
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. */
54 struct value *value_next (struct value *);
56 /* Type of the value. */
58 extern struct type *value_type (struct value *);
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). */
64 extern void deprecated_set_value_type (struct value *value,
65 struct type *type);
67 /* Only used for bitfields; number of bits contained in them. */
69 extern int value_bitsize (struct value *);
70 extern void set_value_bitsize (struct value *, int bit);
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. */
76 extern int value_bitpos (struct value *);
77 extern void set_value_bitpos (struct value *, int bit);
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. */
85 extern int value_offset (struct value *);
86 extern void set_value_offset (struct value *, int offset);
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? */
92 extern int deprecated_value_modifiable (struct value *value);
93 extern void deprecated_set_value_modifiable (struct value *value,
94 int modifiable);
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.
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:
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.
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.
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.
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.)
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. */
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);
145 /* For lval_computed values, this structure holds functions used to
146 retrieve and set the value (or portions of the value).
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. */
153 struct lval_funcs
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);
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);
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.
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);
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.
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);
183 /* Create a computed lvalue, with type TYPE, function pointers FUNCS,
184 and closure CLOSURE. */
186 extern struct value *allocate_computed_value (struct type *type,
187 struct lval_funcs *funcs,
188 void *closure);
190 /* If VALUE is lval_computed, return its lval_funcs structure. */
192 extern struct lval_funcs *value_computed_funcs (struct value *value);
194 /* If VALUE is lval_computed, return its closure. The meaning of the
195 returned value depends on the functions VALUE uses. */
197 extern void *value_computed_closure (struct value *value);
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.
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! */
214 extern int value_lazy (struct value *);
215 extern void set_value_lazy (struct value *value, int val);
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.
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. */
231 extern gdb_byte *value_contents_raw (struct value *);
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. */
239 extern const gdb_byte *value_contents (struct value *);
240 extern gdb_byte *value_contents_writeable (struct value *);
242 /* The ALL variants of the above two macros do not adjust the returned
243 pointer by the embedded_offset value. */
245 extern gdb_byte *value_contents_all_raw (struct value *);
246 extern const gdb_byte *value_contents_all (struct value *);
248 extern int value_fetch_lazy (struct value *val);
249 extern int value_contents_equal (struct value *val1, struct value *val2);
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);
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);
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);
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))
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))
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))
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))
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))
294 /* Convert a REF to the object referenced. */
296 extern struct value *coerce_ref (struct value *value);
298 /* If ARG is an array, convert it to a pointer.
299 If ARG is a function, convert it to a function pointer.
301 References are dereferenced. */
303 extern struct value *coerce_array (struct value *value);
305 /* Internal variables (variables for convenience of use of debugger)
306 are recorded as a chain of these structures. */
308 typedef struct value * (*internalvar_make_value) (struct internalvar *);
310 struct internalvar
312 struct internalvar *next;
313 char *name;
314 struct value *value;
315 internalvar_make_value make_value;
316 int endian;
321 #include "symtab.h"
322 #include "gdbtypes.h"
323 #include "expression.h"
325 struct frame_info;
326 struct fn_field;
328 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
330 extern LONGEST value_as_long (struct value *val);
331 extern DOUBLEST value_as_double (struct value *val);
332 extern CORE_ADDR value_as_address (struct value *val);
334 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
335 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
336 int *invp);
337 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
338 extern LONGEST unpack_field_as_long (struct type *type,
339 const gdb_byte *valaddr,
340 int fieldno);
342 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
344 extern struct value *value_from_longest (struct type *type, LONGEST num);
345 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
346 extern struct value *value_from_double (struct type *type, DOUBLEST num);
347 extern struct value *value_from_decfloat (struct type *type,
348 const gdb_byte *decbytes);
349 extern struct value *value_from_string (char *string);
351 extern struct value *value_at (struct type *type, CORE_ADDR addr);
352 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
354 extern struct value *value_from_contents_and_address (struct type *,
355 const gdb_byte *,
356 CORE_ADDR);
358 extern struct value *default_value_from_register (struct type *type,
359 int regnum,
360 struct frame_info *frame);
362 extern struct value *value_from_register (struct type *type, int regnum,
363 struct frame_info *frame);
365 extern CORE_ADDR address_from_register (struct type *type, int regnum,
366 struct frame_info *frame);
368 extern struct value *value_of_variable (struct symbol *var, struct block *b);
370 extern struct value *address_of_variable (struct symbol *var, struct block *b);
372 extern struct value *value_of_register (int regnum, struct frame_info *frame);
374 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
376 extern int symbol_read_needs_frame (struct symbol *);
378 extern struct value *read_var_value (struct symbol *var,
379 struct frame_info *frame);
381 extern struct value *allocate_value (struct type *type);
382 extern struct value *allocate_value_lazy (struct type *type);
383 extern void allocate_value_contents (struct value *value);
385 extern struct value *allocate_repeat_value (struct type *type, int count);
387 extern struct value *value_mark (void);
389 extern void value_free_to_mark (struct value *mark);
391 extern struct value *value_string (char *ptr, int len);
392 extern struct value *value_bitstring (char *ptr, int len);
394 extern struct value *value_array (int lowbound, int highbound,
395 struct value **elemvec);
397 extern struct value *value_concat (struct value *arg1, struct value *arg2);
399 extern struct value *value_binop (struct value *arg1, struct value *arg2,
400 enum exp_opcode op);
402 extern struct value *value_ptradd (struct value *arg1, struct value *arg2);
404 extern struct value *value_ptrsub (struct value *arg1, struct value *arg2);
406 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
408 extern int value_must_coerce_to_target (struct value *arg1);
410 extern struct value *value_coerce_to_target (struct value *arg1);
412 extern struct value *value_coerce_array (struct value *arg1);
414 extern struct value *value_coerce_function (struct value *arg1);
416 extern struct value *value_ind (struct value *arg1);
418 extern struct value *value_addr (struct value *arg1);
420 extern struct value *value_ref (struct value *arg1);
422 extern struct value *value_assign (struct value *toval,
423 struct value *fromval);
425 extern struct value *value_pos (struct value *arg1);
427 extern struct value *value_neg (struct value *arg1);
429 extern struct value *value_complement (struct value *arg1);
431 extern struct value *value_struct_elt (struct value **argp,
432 struct value **args,
433 char *name, int *static_memfuncp,
434 char *err);
436 extern struct value *value_aggregate_elt (struct type *curtype,
437 char *name,
438 int want_address,
439 enum noside noside);
441 extern struct value *value_static_field (struct type *type, int fieldno);
443 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
444 int, int *,
445 struct type **, int *);
447 extern int find_overload_match (struct type **arg_types, int nargs,
448 char *name, int method, int lax,
449 struct value **objp, struct symbol *fsym,
450 struct value **valp, struct symbol **symp,
451 int *staticp);
453 extern struct value *value_field (struct value *arg1, int fieldno);
455 extern struct value *value_primitive_field (struct value *arg1, int offset,
456 int fieldno,
457 struct type *arg_type);
460 extern struct type *value_rtti_target_type (struct value *, int *, int *,
461 int *);
463 extern struct value *value_full_object (struct value *, struct type *, int,
464 int, int);
466 extern struct value *value_cast_pointers (struct type *, struct value *);
468 extern struct value *value_cast (struct type *type, struct value *arg2);
470 extern struct value *value_zero (struct type *type, enum lval_type lv);
472 extern struct value *value_one (struct type *type, enum lval_type lv);
474 extern struct value *value_repeat (struct value *arg1, int count);
476 extern struct value *value_subscript (struct value *array, struct value *idx);
478 extern struct value *value_bitstring_subscript (struct type *type,
479 struct value *bitstring,
480 struct value *idx);
482 extern struct value *register_value_being_returned (struct type *valtype,
483 struct regcache *retbuf);
485 extern int value_in (struct value *element, struct value *set);
487 extern int value_bit_index (struct type *type, const gdb_byte *addr,
488 int index);
490 extern int using_struct_return (struct type *func_type,
491 struct type *value_type);
493 extern struct value *evaluate_expression (struct expression *exp);
495 extern struct value *evaluate_type (struct expression *exp);
497 extern struct value *evaluate_subexpression_type (struct expression *exp,
498 int subexp);
500 extern char *extract_field_op (struct expression *exp, int *subexp);
502 extern struct value *evaluate_subexp_with_coercion (struct expression *,
503 int *, enum noside);
505 extern struct value *parse_and_eval (char *exp);
507 extern struct value *parse_to_comma_and_eval (char **expp);
509 extern struct type *parse_and_eval_type (char *p, int length);
511 extern CORE_ADDR parse_and_eval_address (char *exp);
513 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
515 extern LONGEST parse_and_eval_long (char *exp);
517 extern void unop_promote (const struct language_defn *language,
518 struct gdbarch *gdbarch,
519 struct value **arg1);
521 extern void binop_promote (const struct language_defn *language,
522 struct gdbarch *gdbarch,
523 struct value **arg1, struct value **arg2);
525 extern struct value *access_value_history (int num);
527 extern struct value *value_of_internalvar (struct internalvar *var);
529 extern void set_internalvar (struct internalvar *var, struct value *val);
531 extern void set_internalvar_component (struct internalvar *var,
532 int offset,
533 int bitpos, int bitsize,
534 struct value *newvalue);
536 extern struct internalvar *lookup_only_internalvar (char *name);
538 extern struct internalvar *create_internalvar (char *name);
540 extern struct internalvar *
541 create_internalvar_type_lazy (char *name, internalvar_make_value fun);
543 extern struct internalvar *lookup_internalvar (char *name);
545 extern int value_equal (struct value *arg1, struct value *arg2);
547 extern int value_less (struct value *arg1, struct value *arg2);
549 extern int value_logical_not (struct value *arg1);
551 /* C++ */
553 extern struct value *value_of_this (int complain);
555 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
556 enum exp_opcode op,
557 enum exp_opcode otherop,
558 enum noside noside);
560 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
561 enum noside noside);
563 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
564 int j, struct type *type, int offset);
566 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
567 struct value *arg2);
569 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
571 extern int destructor_name_p (const char *name, const struct type *type);
573 extern void value_free (struct value *val);
575 extern void free_all_values (void);
577 extern void release_value (struct value *val);
579 extern int record_latest_value (struct value *val);
581 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
582 int bitsize);
584 extern void type_print (struct type *type, char *varstring,
585 struct ui_file *stream, int show);
587 extern char *type_to_string (struct type *type);
589 extern gdb_byte *baseclass_addr (struct type *type, int index,
590 gdb_byte *valaddr,
591 struct value **valuep, int *errp);
593 extern void print_longest (struct ui_file *stream, int format,
594 int use_local, LONGEST val);
596 extern void print_floating (const gdb_byte *valaddr, struct type *type,
597 struct ui_file *stream);
599 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
600 struct ui_file *stream);
602 extern int value_print (struct value *val, struct ui_file *stream,
603 const struct value_print_options *options);
605 extern void value_print_array_elements (struct value *val,
606 struct ui_file *stream, int format,
607 enum val_prettyprint pretty);
609 extern struct value *value_release_to_mark (struct value *mark);
611 extern int val_print (struct type *type, const gdb_byte *valaddr,
612 int embedded_offset, CORE_ADDR address,
613 struct ui_file *stream, int recurse,
614 const struct value_print_options *options,
615 const struct language_defn *language);
617 extern int common_val_print (struct value *val,
618 struct ui_file *stream, int recurse,
619 const struct value_print_options *options,
620 const struct language_defn *language);
622 extern int val_print_string (CORE_ADDR addr, int len, int width,
623 struct ui_file *stream,
624 const struct value_print_options *options);
626 extern void print_variable_and_value (const char *name,
627 struct symbol *var,
628 struct frame_info *frame,
629 struct ui_file *stream,
630 int indent);
632 extern int check_field (struct type *, const char *);
634 extern void typedef_print (struct type *type, struct symbol *news,
635 struct ui_file *stream);
637 extern char *internalvar_name (struct internalvar *var);
639 extern void preserve_values (struct objfile *);
641 /* From values.c */
643 extern struct value *value_copy (struct value *);
645 /* From valops.c */
647 extern struct value *varying_to_slice (struct value *);
649 extern struct value *value_slice (struct value *, int, int);
651 extern struct value *value_literal_complex (struct value *, struct value *,
652 struct type *);
654 extern struct value *find_function_in_inferior (const char *,
655 struct objfile **);
657 extern struct value *value_allocate_space_in_inferior (int);
659 extern struct value *value_of_local (const char *name, int complain);
661 extern struct value * value_subscripted_rvalue (struct value *array, struct value *idx, int lowerbound);
662 #endif /* !defined (VALUE_H) */