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1/* Definitions for values of C expressions, for GDB.
2
3 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
4 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
5 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 2 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, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
23
24#if !defined (VALUE_H)
25#define VALUE_H 1
26
27#include "doublest.h"
28#include "frame.h" /* For struct frame_id. */
29
30struct block;
31struct expression;
32struct regcache;
33struct symbol;
34struct type;
35struct ui_file;
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
42struct value
43{
44 /* Type of value; either not an lval, or one of the various
45 different possible kinds of lval. */
46 enum lval_type lval;
47
48 /* Is it modifiable? Only relevant if lval != not_lval. */
49 int modifiable;
50
51 /* Location of value (if lval). */
52 union
53 {
54 /* If lval == lval_memory, this is the address in the inferior.
55 If lval == lval_register, this is the byte offset into the
56 registers structure. */
57 CORE_ADDR address;
58
59 /* Pointer to internal variable. */
60 struct internalvar *internalvar;
61
62 /* Number of register. Only used with lval_reg_frame_relative. */
63 int regnum;
64 } location;
65
66 /* Describes offset of a value within lval of a structure in bytes.
67 If lval == lval_memory, this is an offset to the address.
68 If lval == lval_register, this is a further offset from
69 location.address within the registers structure.
70 Note also the member embedded_offset below. */
71 int offset;
72
73 /* Only used for bitfields; number of bits contained in them. */
74 int bitsize;
75
76 /* Only used for bitfields; position of start of field.
77 For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
78 For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
79 int bitpos;
80
81 /* Frame value is relative to. In practice, this ID is only used if
82 the value is stored in several registers in other than the
83 current frame, and these registers have not all been saved at the
84 same place in memory. This will be described in the lval enum
85 above as "lval_reg_frame_relative". */
86 struct frame_id frame_id;
87
88 /* Type of the value. */
89 struct type *type;
90
91 /* If a value represents a C++ object, then the `type' field gives
92 the object's compile-time type. If the object actually belongs
93 to some class derived from `type', perhaps with other base
94 classes and additional members, then `type' is just a subobject
95 of the real thing, and the full object is probably larger than
96 `type' would suggest.
97
98 If `type' is a dynamic class (i.e. one with a vtable), then GDB
99 can actually determine the object's run-time type by looking at
100 the run-time type information in the vtable. When this
101 information is available, we may elect to read in the entire
102 object, for several reasons:
103
104 - When printing the value, the user would probably rather see the
105 full object, not just the limited portion apparent from the
106 compile-time type.
107
108 - If `type' has virtual base classes, then even printing `type'
109 alone may require reaching outside the `type' portion of the
110 object to wherever the virtual base class has been stored.
111
112 When we store the entire object, `enclosing_type' is the run-time
113 type -- the complete object -- and `embedded_offset' is the
114 offset of `type' within that larger type, in bytes. The
115 VALUE_CONTENTS macro takes `embedded_offset' into account, so
116 most GDB code continues to see the `type' portion of the value,
117 just as the inferior would.
118
119 If `type' is a pointer to an object, then `enclosing_type' is a
120 pointer to the object's run-time type, and `pointed_to_offset' is
121 the offset in bytes from the full object to the pointed-to object
122 -- that is, the value `embedded_offset' would have if we
123 followed the pointer and fetched the complete object. (I don't
124 really see the point. Why not just determine the run-time type
125 when you indirect, and avoid the special case? The contents
126 don't matter until you indirect anyway.)
127
128 If we're not doing anything fancy, `enclosing_type' is equal to
129 `type', and `embedded_offset' is zero, so everything works
130 normally. */
131 struct type *enclosing_type;
132 int embedded_offset;
133 int pointed_to_offset;
134
135 /* Values are stored in a chain, so that they can be deleted
136 easily over calls to the inferior. Values assigned to internal
137 variables or put into the value history are taken off this
138 list. */
139 struct value *next;
140
141 /* Register number if the value is from a register. */
142 short regno;
143
144 /* If zero, contents of this value are in the contents field. If
145 nonzero, contents are in inferior memory at address in the
146 location.address field plus the offset field (and the lval
147 field should be lval_memory).
148
149 WARNING: This field is used by the code which handles
150 watchpoints (see breakpoint.c) to decide whether a particular
151 value can be watched by hardware watchpoints. If the lazy flag
152 is set for some member of a value chain, it is assumed that
153 this member of the chain doesn't need to be watched as part of
154 watching the value itself. This is how GDB avoids watching the
155 entire struct or array when the user wants to watch a single
156 struct member or array element. If you ever change the way
157 lazy flag is set and reset, be sure to consider this use as
158 well! */
159 char lazy;
160
161 /* If nonzero, this is the value of a variable which does not
162 actually exist in the program. */
163 char optimized_out;
164
165 /* The BFD section associated with this value. */
166 asection *bfd_section;
167
168 /* Actual contents of the value. For use of this value; setting
169 it uses the stuff above. Not valid if lazy is nonzero.
170 Target byte-order. We force it to be aligned properly for any
171 possible value. Note that a value therefore extends beyond
172 what is declared here. */
173 union
174 {
175 long contents[1];
176 DOUBLEST force_doublest_align;
177 LONGEST force_longest_align;
178 CORE_ADDR force_core_addr_align;
179 void *force_pointer_align;
180 } aligner;
181 /* Do not add any new members here -- contents above will trash them. */
182};
183
184#define VALUE_TYPE(val) (val)->type
185#define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
186#define VALUE_LAZY(val) (val)->lazy
187
188/* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
189 the gdb buffer used to hold a copy of the contents of the lval.
190 VALUE_CONTENTS is used when the contents of the buffer are needed
191 -- it uses value_fetch_lazy() to load the buffer from the process
192 being debugged if it hasn't already been loaded.
193 VALUE_CONTENTS_RAW is used when data is being stored into the
194 buffer, or when it is certain that the contents of the buffer are
195 valid.
196
197 Note: The contents pointer is adjusted by the offset required to
198 get to the real subobject, if the value happens to represent
199 something embedded in a larger run-time object. */
200
201#define VALUE_CONTENTS_RAW(val) \
202 ((char *) (val)->aligner.contents + (val)->embedded_offset)
203#define VALUE_CONTENTS(val) \
204 ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)), VALUE_CONTENTS_RAW(val))
205
206/* The ALL variants of the above two macros do not adjust the returned
207 pointer by the embedded_offset value. */
208
209#define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
210#define VALUE_CONTENTS_ALL(val) \
211 ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)), \
212 VALUE_CONTENTS_ALL_RAW(val))
213
214extern int value_fetch_lazy (struct value *val);
215
216#define VALUE_LVAL(val) (val)->lval
217#define VALUE_ADDRESS(val) (val)->location.address
218#define VALUE_INTERNALVAR(val) (val)->location.internalvar
219#define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
220#define VALUE_FRAME_ID(val) ((val)->frame_id)
221#define VALUE_OFFSET(val) (val)->offset
222#define VALUE_BITSIZE(val) (val)->bitsize
223#define VALUE_BITPOS(val) (val)->bitpos
224#define VALUE_NEXT(val) (val)->next
225#define VALUE_REGNO(val) (val)->regno
226#define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
227#define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
228#define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
229#define VALUE_BFD_SECTION(val) ((val)->bfd_section)
230
231/* Convert a REF to the object referenced. */
232
233#define COERCE_REF(arg) \
234 do { \
235 struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg)); \
236 if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF) \
237 arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp), \
238 unpack_pointer (VALUE_TYPE (arg), \
239 VALUE_CONTENTS (arg)), \
240 VALUE_BFD_SECTION (arg)); \
241 } while (0)
242
243/* If ARG is an array, convert it to a pointer.
244 If ARG is an enum, convert it to an integer.
245 If ARG is a function, convert it to a function pointer.
246
247 References are dereferenced. */
248
249#define COERCE_ARRAY(arg) \
250 do { \
251 COERCE_REF(arg); \
252 if (current_language->c_style_arrays \
253 && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY) \
254 arg = value_coerce_array (arg); \
255 if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC) \
256 arg = value_coerce_function (arg); \
257 } while (0)
258
259#define COERCE_NUMBER(arg) \
260 do { COERCE_ARRAY(arg); COERCE_ENUM(arg); } while (0)
261
262/* NOTE: cagney/2002-12-17: This macro was handling a chill language
263 problem but that language has gone away. */
264#define COERCE_VARYING_ARRAY(arg, real_arg_type)
265
266/* If ARG is an enum, convert it to an integer. */
267
268#define COERCE_ENUM(arg) \
269 do { \
270 if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM) \
271 arg = value_cast (builtin_type_unsigned_int, arg); \
272 } while (0)
273
274/* Internal variables (variables for convenience of use of debugger)
275 are recorded as a chain of these structures. */
276
277struct internalvar
278{
279 struct internalvar *next;
280 char *name;
281 struct value *value;
282};
283
284/* Pointer to member function. Depends on compiler implementation. */
285
286#define METHOD_PTR_IS_VIRTUAL(ADDR) ((ADDR) & 0x80000000)
287#define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
288#define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
289\f
290
291#include "symtab.h"
292#include "gdbtypes.h"
293#include "expression.h"
294
295struct frame_info;
296struct fn_field;
297
298extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
299
300extern LONGEST value_as_long (struct value *val);
301extern DOUBLEST value_as_double (struct value *val);
302extern CORE_ADDR value_as_address (struct value *val);
303
304extern LONGEST unpack_long (struct type *type, const char *valaddr);
305extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
306 int *invp);
307extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
308extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
309 int fieldno);
310
311extern struct value *value_from_longest (struct type *type, LONGEST num);
312extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
313extern struct value *value_from_double (struct type *type, DOUBLEST num);
314extern struct value *value_from_string (char *string);
315
316extern struct value *value_at (struct type *type, CORE_ADDR addr,
317 asection * sect);
318extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
319 asection * sect);
320
321extern struct value *value_from_register (struct type *type, int regnum,
322 struct frame_info *frame);
323
324extern struct value *value_of_variable (struct symbol *var, struct block *b);
325
326extern struct value *value_of_register (int regnum,
327 struct frame_info *frame);
328
329extern int symbol_read_needs_frame (struct symbol *);
330
331extern struct value *read_var_value (struct symbol *var,
332 struct frame_info *frame);
333
334extern struct value *locate_var_value (struct symbol *var,
335 struct frame_info *frame);
336
337extern struct value *allocate_value (struct type *type);
338
339extern struct value *allocate_repeat_value (struct type *type, int count);
340
341extern struct value *value_change_enclosing_type (struct value *val,
342 struct type *new_type);
343
344extern struct value *value_mark (void);
345
346extern void value_free_to_mark (struct value *mark);
347
348extern struct value *value_string (char *ptr, int len);
349extern struct value *value_bitstring (char *ptr, int len);
350
351extern struct value *value_array (int lowbound, int highbound,
352 struct value ** elemvec);
353
354extern struct value *value_concat (struct value *arg1, struct value *arg2);
355
356extern struct value *value_binop (struct value *arg1, struct value *arg2,
357 enum exp_opcode op);
358
359extern struct value *value_add (struct value *arg1, struct value *arg2);
360
361extern struct value *value_sub (struct value *arg1, struct value *arg2);
362
363extern struct value *value_coerce_array (struct value *arg1);
364
365extern struct value *value_coerce_function (struct value *arg1);
366
367extern struct value *value_ind (struct value *arg1);
368
369extern struct value *value_addr (struct value *arg1);
370
371extern struct value *value_assign (struct value *toval, struct value *fromval);
372
373extern struct value *value_neg (struct value *arg1);
374
375extern struct value *value_complement (struct value *arg1);
376
377extern struct value *value_struct_elt (struct value **argp,
378 struct value **args,
379 char *name, int *static_memfuncp,
380 char *err);
381
382extern struct value *value_aggregate_elt (struct type *curtype,
383 char *name,
384 enum noside noside);
385
386extern struct value *value_static_field (struct type *type, int fieldno);
387
388extern struct fn_field *value_find_oload_method_list (struct value **, char *,
389 int, int *,
390 struct type **, int *);
391
392extern int find_overload_match (struct type **arg_types, int nargs,
393 char *name, int method, int lax,
394 struct value **objp, struct symbol *fsym,
395 struct value **valp, struct symbol **symp,
396 int *staticp);
397
398extern struct value *value_field (struct value *arg1, int fieldno);
399
400extern struct value *value_primitive_field (struct value *arg1, int offset,
401 int fieldno,
402 struct type *arg_type);
403
404
405extern struct type *value_rtti_target_type (struct value *, int *, int *,
406 int *);
407
408extern struct value *value_full_object (struct value *, struct type *, int,
409 int, int);
410
411extern struct value *value_cast (struct type *type, struct value *arg2);
412
413extern struct value *value_zero (struct type *type, enum lval_type lv);
414
415extern struct value *value_repeat (struct value *arg1, int count);
416
417extern struct value *value_subscript (struct value *array, struct value *idx);
418
419extern struct value *register_value_being_returned (struct type *valtype,
420 struct regcache *retbuf);
421
422extern struct value *value_in (struct value *element, struct value *set);
423
424extern int value_bit_index (struct type *type, char *addr, int index);
425
426extern int using_struct_return (struct type *value_type, int gcc_p);
427
428extern struct value *evaluate_expression (struct expression *exp);
429
430extern struct value *evaluate_type (struct expression *exp);
431
432extern struct value *evaluate_subexp_with_coercion (struct expression *,
433 int *, enum noside);
434
435extern struct value *parse_and_eval (char *exp);
436
437extern struct value *parse_to_comma_and_eval (char **expp);
438
439extern struct type *parse_and_eval_type (char *p, int length);
440
441extern CORE_ADDR parse_and_eval_address (char *exp);
442
443extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
444
445extern LONGEST parse_and_eval_long (char *exp);
446
447extern struct value *access_value_history (int num);
448
449extern struct value *value_of_internalvar (struct internalvar *var);
450
451extern void set_internalvar (struct internalvar *var, struct value *val);
452
453extern void set_internalvar_component (struct internalvar *var,
454 int offset,
455 int bitpos, int bitsize,
456 struct value *newvalue);
457
458extern struct internalvar *lookup_internalvar (char *name);
459
460extern int value_equal (struct value *arg1, struct value *arg2);
461
462extern int value_less (struct value *arg1, struct value *arg2);
463
464extern int value_logical_not (struct value *arg1);
465
466/* C++ */
467
468extern struct value *value_of_this (int complain);
469
470extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
471 enum exp_opcode op,
472 enum exp_opcode otherop,
473 enum noside noside);
474
475extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
476 enum noside noside);
477
478extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
479 int j, struct type *type, int offset);
480
481extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
482 struct value *arg2);
483
484extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
485
486extern int destructor_name_p (const char *name, const struct type *type);
487
488#define value_free(val) xfree (val)
489
490extern void free_all_values (void);
491
492extern void release_value (struct value *val);
493
494extern int record_latest_value (struct value *val);
495
496extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
497 int bitsize);
498
499extern void type_print (struct type * type, char *varstring,
500 struct ui_file * stream, int show);
501
502extern char *baseclass_addr (struct type *type, int index, char *valaddr,
503 struct value **valuep, int *errp);
504
505extern void print_longest (struct ui_file * stream, int format,
506 int use_local, LONGEST val);
507
508extern void print_floating (char *valaddr, struct type * type,
509 struct ui_file * stream);
510
511extern int value_print (struct value *val, struct ui_file *stream, int format,
512 enum val_prettyprint pretty);
513
514extern void value_print_array_elements (struct value *val,
515 struct ui_file *stream, int format,
516 enum val_prettyprint pretty);
517
518extern struct value *value_release_to_mark (struct value *mark);
519
520extern int val_print (struct type * type, char *valaddr,
521 int embedded_offset, CORE_ADDR address,
522 struct ui_file * stream, int format,
523 int deref_ref, int recurse,
524 enum val_prettyprint pretty);
525
526extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
527
528extern void print_variable_value (struct symbol * var,
529 struct frame_info * frame,
530 struct ui_file *stream);
531
532extern int check_field (struct value *, const char *);
533
534extern void typedef_print (struct type * type, struct symbol * news,
535 struct ui_file * stream);
536
537extern char *internalvar_name (struct internalvar *var);
538
539extern void clear_value_history (void);
540
541extern void clear_internalvars (void);
542
543/* From values.c */
544
545extern struct value *value_copy (struct value *);
546
547/* From valops.c */
548
549extern struct value *varying_to_slice (struct value *);
550
551extern struct value *value_slice (struct value *, int, int);
552
553extern struct value *value_literal_complex (struct value *, struct value *,
554 struct type *);
555
556extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
557 int *, int *);
558
559extern struct value *find_function_in_inferior (const char *);
560
561extern struct value *value_allocate_space_in_inferior (int);
562
563extern struct value *value_of_local (const char *name, int complain);
564
565#endif /* !defined (VALUE_H) */
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