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 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 /* If zero, contents of this value are in the contents field.  If
 146    nonzero, contents are in inferior.  If the lval field is lval_memory,
 147    the contents are in inferior memory at location.address plus offset.
 148    The lval field may also be lval_register.
 149
 150    WARNING: This field is used by the code which handles watchpoints
 151    (see breakpoint.c) to decide whether a particular value can be
 152    watched by hardware watchpoints.  If the lazy flag is set for some
 153    member of a value chain, it is assumed that this member of the
 154    chain doesn't need to be watched as part of watching the value
 155    itself.  This is how GDB avoids watching the entire struct or array
 156    when the user wants to watch a single struct member or array
 157    element.  If you ever change the way lazy flag is set and reset, be
 158    sure to consider this use as well!  */
 159
 160 extern int value_lazy (struct value *);
 161 extern void set_value_lazy (struct value *value, int val);
 162
 163 /* value_contents() and value_contents_raw() both return the address
 164    of the gdb buffer used to hold a copy of the contents of the lval.
 165    value_contents() is used when the contents of the buffer are needed
 166    -- it uses value_fetch_lazy() to load the buffer from the process
 167    being debugged if it hasn't already been loaded
 168    (value_contents_writeable() is used when a writeable but fetched
 169    buffer is required)..  value_contents_raw() is used when data is
 170    being stored into the buffer, or when it is certain that the
 171    contents of the buffer are valid.
 172
 173    Note: The contents pointer is adjusted by the offset required to
 174    get to the real subobject, if the value happens to represent
 175    something embedded in a larger run-time object.  */
 176
 177 extern gdb_byte *value_contents_raw (struct value *);
 178
 179 /* Actual contents of the value.  For use of this value; setting it
 180    uses the stuff above.  Not valid if lazy is nonzero.  Target
 181    byte-order.  We force it to be aligned properly for any possible
 182    value.  Note that a value therefore extends beyond what is
 183    declared here.  */
 184
 185 extern const gdb_byte *value_contents (struct value *);
 186 extern gdb_byte *value_contents_writeable (struct value *);
 187
 188 /* The ALL variants of the above two macros do not adjust the returned
 189    pointer by the embedded_offset value.  */
 190
 191 extern gdb_byte *value_contents_all_raw (struct value *);
 192 extern const gdb_byte *value_contents_all (struct value *);
 193
 194 extern int value_fetch_lazy (struct value *val);
 195 extern int value_contents_equal (struct value *val1, struct value *val2);
 196
 197 /* If nonzero, this is the value of a variable which does not actually
 198    exist in the program.  */
 199 extern int value_optimized_out (struct value *value);
 200 extern void set_value_optimized_out (struct value *value, int val);
 201
 202 /* Set or return field indicating whether a variable is initialized or
 203    not, based on debugging information supplied by the compiler.
 204    1 = initialized; 0 = uninitialized.  */
 205 extern int value_initialized (struct value *);
 206 extern void set_value_initialized (struct value *, int);
 207
 208 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 209    single value might have multiple LVALs), this hacked interface is
 210    limited to just the first PIECE.  Expect further change.  */
 211 /* Type of value; either not an lval, or one of the various different
 212    possible kinds of lval.  */
 213 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 214 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 215
 216 /* If lval == lval_memory, this is the address in the inferior.  If
 217    lval == lval_register, this is the byte offset into the registers
 218    structure.  */
 219 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 220 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 221
 222 /* Pointer to internal variable.  */
 223 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 224 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 225
 226 /* Frame register value is relative to.  This will be described in the
 227    lval enum above as "lval_register".  */
 228 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 229 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 230
 231 /* Register number if the value is from a register.  */
 232 extern short *deprecated_value_regnum_hack (struct value *);
 233 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 234
 235 /* Convert a REF to the object referenced.  */
 236
 237 extern struct value *coerce_ref (struct value *value);
 238
 239 /* If ARG is an array, convert it to a pointer.
 240    If ARG is a function, convert it to a function pointer.
 241
 242    References are dereferenced.  */
 243
 244 extern struct value *coerce_array (struct value *value);
 245
 246 /* Internal variables (variables for convenience of use of debugger)
 247    are recorded as a chain of these structures.  */
 248
 249 struct internalvar
 250 {
 251   struct internalvar *next;
 252   char *name;
 253   struct value *value;
 254   int endian;
 255 };
 256
 257 \f
 258
 259 #include "symtab.h"
 260 #include "gdbtypes.h"
 261 #include "expression.h"
 262
 263 struct frame_info;
 264 struct fn_field;
 265
 266 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 267
 268 extern LONGEST value_as_long (struct value *val);
 269 extern DOUBLEST value_as_double (struct value *val);
 270 extern CORE_ADDR value_as_address (struct value *val);
 271
 272 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
 273 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
 274                                int *invp);
 275 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
 276 extern LONGEST unpack_field_as_long (struct type *type,
 277                                      const gdb_byte *valaddr,
 278                                      int fieldno);
 279
 280 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
 281
 282 extern struct value *value_from_longest (struct type *type, LONGEST num);
 283 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 284 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 285 extern struct value *value_from_decfloat (struct type *type,
 286                                           const gdb_byte *decbytes);
 287 extern struct value *value_from_string (char *string);
 288
 289 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 290 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 291
 292 extern struct value *default_value_from_register (struct type *type,
 293                                                   int regnum,
 294                                                   struct frame_info *frame);
 295
 296 extern struct value *value_from_register (struct type *type, int regnum,
 297                                           struct frame_info *frame);
 298
 299 extern CORE_ADDR address_from_register (struct type *type, int regnum,
 300                                         struct frame_info *frame);
 301
 302 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 303
 304 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 305
 306 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
 307
 308 extern int symbol_read_needs_frame (struct symbol *);
 309
 310 extern struct value *read_var_value (struct symbol *var,
 311                                      struct frame_info *frame);
 312
 313 extern struct value *locate_var_value (struct symbol *var,
 314                                        struct frame_info *frame);
 315
 316 extern struct value *allocate_value (struct type *type);
 317
 318 extern struct value *allocate_repeat_value (struct type *type, int count);
 319
 320 extern struct value *value_mark (void);
 321
 322 extern void value_free_to_mark (struct value *mark);
 323
 324 extern struct value *value_string (char *ptr, int len);
 325 extern struct value *value_bitstring (char *ptr, int len);
 326
 327 extern struct value *value_array (int lowbound, int highbound,
 328                                   struct value **elemvec);
 329
 330 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 331
 332 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 333                                   enum exp_opcode op);
 334
 335 extern struct value *value_ptradd (struct value *arg1, struct value *arg2);
 336
 337 extern struct value *value_ptrsub (struct value *arg1, struct value *arg2);
 338
 339 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
 340
 341 extern int value_must_coerce_to_target (struct value *arg1);
 342
 343 extern struct value *value_coerce_to_target (struct value *arg1);
 344
 345 extern struct value *value_coerce_array (struct value *arg1);
 346
 347 extern struct value *value_coerce_function (struct value *arg1);
 348
 349 extern struct value *value_ind (struct value *arg1);
 350
 351 extern struct value *value_addr (struct value *arg1);
 352
 353 extern struct value *value_ref (struct value *arg1);
 354
 355 extern struct value *value_assign (struct value *toval,
 356                                    struct value *fromval);
 357
 358 extern struct value *value_pos (struct value *arg1);
 359
 360 extern struct value *value_neg (struct value *arg1);
 361
 362 extern struct value *value_complement (struct value *arg1);
 363
 364 extern struct value *value_struct_elt (struct value **argp,
 365                                        struct value **args,
 366                                        char *name, int *static_memfuncp,
 367                                        char *err);
 368
 369 extern struct value *value_aggregate_elt (struct type *curtype,
 370                                           char *name,
 371                                           int want_address,
 372                                           enum noside noside);
 373
 374 extern struct value *value_static_field (struct type *type, int fieldno);
 375
 376 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 377                                                       int, int *,
 378                                                       struct type **, int *);
 379
 380 extern int find_overload_match (struct type **arg_types, int nargs,
 381                                 char *name, int method, int lax,
 382                                 struct value **objp, struct symbol *fsym,
 383                                 struct value **valp, struct symbol **symp,
 384                                 int *staticp);
 385
 386 extern struct value *value_field (struct value *arg1, int fieldno);
 387
 388 extern struct value *value_primitive_field (struct value *arg1, int offset,
 389                                             int fieldno,
 390                                             struct type *arg_type);
 391
 392
 393 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 394                                             int *);
 395
 396 extern struct value *value_full_object (struct value *, struct type *, int,
 397                                         int, int);
 398
 399 extern struct value *value_cast_pointers (struct type *, struct value *);
 400
 401 extern struct value *value_cast (struct type *type, struct value *arg2);
 402
 403 extern struct value *value_zero (struct type *type, enum lval_type lv);
 404
 405 extern struct value *value_one (struct type *type, enum lval_type lv);
 406
 407 extern struct value *value_repeat (struct value *arg1, int count);
 408
 409 extern struct value *value_subscript (struct value *array, struct value *idx);
 410
 411 extern struct value *value_bitstring_subscript (struct type *type,
 412                                                 struct value *bitstring,
 413                                                 struct value *idx);
 414
 415 extern struct value *register_value_being_returned (struct type *valtype,
 416                                                     struct regcache *retbuf);
 417
 418 extern int value_in (struct value *element, struct value *set);
 419
 420 extern int value_bit_index (struct type *type, const gdb_byte *addr,
 421                             int index);
 422
 423 extern int using_struct_return (struct type *func_type,
 424                                 struct type *value_type);
 425
 426 extern struct value *evaluate_expression (struct expression *exp);
 427
 428 extern struct value *evaluate_type (struct expression *exp);
 429
 430 extern struct value *evaluate_subexpression_type (struct expression *exp,
 431                                                   int subexp);
 432
 433 extern char *extract_field_op (struct expression *exp, int *subexp);
 434
 435 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 436                                                     int *, enum noside);
 437
 438 extern struct value *parse_and_eval (char *exp);
 439
 440 extern struct value *parse_to_comma_and_eval (char **expp);
 441
 442 extern struct type *parse_and_eval_type (char *p, int length);
 443
 444 extern CORE_ADDR parse_and_eval_address (char *exp);
 445
 446 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 447
 448 extern LONGEST parse_and_eval_long (char *exp);
 449
 450 extern void unop_promote (const struct language_defn *language,
 451                           struct gdbarch *gdbarch,
 452                           struct value **arg1);
 453
 454 extern void binop_promote (const struct language_defn *language,
 455                            struct gdbarch *gdbarch,
 456                            struct value **arg1, struct value **arg2);
 457
 458 extern struct value *access_value_history (int num);
 459
 460 extern struct value *value_of_internalvar (struct internalvar *var);
 461
 462 extern void set_internalvar (struct internalvar *var, struct value *val);
 463
 464 extern void set_internalvar_component (struct internalvar *var,
 465                                        int offset,
 466                                        int bitpos, int bitsize,
 467                                        struct value *newvalue);
 468
 469 extern struct internalvar *lookup_only_internalvar (char *name);
 470
 471 extern struct internalvar *create_internalvar (char *name);
 472
 473 extern struct internalvar *lookup_internalvar (char *name);
 474
 475 extern int value_equal (struct value *arg1, struct value *arg2);
 476
 477 extern int value_less (struct value *arg1, struct value *arg2);
 478
 479 extern int value_logical_not (struct value *arg1);
 480
 481 /* C++ */
 482
 483 extern struct value *value_of_this (int complain);
 484
 485 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 486                                     enum exp_opcode op,
 487                                     enum exp_opcode otherop,
 488                                     enum noside noside);
 489
 490 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 491                                    enum noside noside);
 492
 493 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 494                                      int j, struct type *type, int offset);
 495
 496 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 497                                  struct value *arg2);
 498
 499 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 500
 501 extern int destructor_name_p (const char *name, const struct type *type);
 502
 503 #define value_free(val) xfree (val)
 504
 505 extern void free_all_values (void);
 506
 507 extern void release_value (struct value *val);
 508
 509 extern int record_latest_value (struct value *val);
 510
 511 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
 512                           int bitsize);
 513
 514 extern void type_print (struct type *type, char *varstring,
 515                         struct ui_file *stream, int show);
 516
 517 extern gdb_byte *baseclass_addr (struct type *type, int index,
 518                                  gdb_byte *valaddr,
 519                                  struct value **valuep, int *errp);
 520
 521 extern void print_longest (struct ui_file *stream, int format,
 522                            int use_local, LONGEST val);
 523
 524 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 525                             struct ui_file *stream);
 526
 527 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
 528                                     struct ui_file *stream);
 529
 530 extern int value_print (struct value *val, struct ui_file *stream,
 531                         const struct value_print_options *options);
 532
 533 extern void value_print_array_elements (struct value *val,
 534                                         struct ui_file *stream, int format,
 535                                         enum val_prettyprint pretty);
 536
 537 extern struct value *value_release_to_mark (struct value *mark);
 538
 539 extern int val_print (struct type *type, const gdb_byte *valaddr,
 540                       int embedded_offset, CORE_ADDR address,
 541                       struct ui_file *stream, int recurse,
 542                       const struct value_print_options *options,
 543                       const struct language_defn *language);
 544
 545 extern int common_val_print (struct value *val,
 546                              struct ui_file *stream, int recurse,
 547                              const struct value_print_options *options,
 548                              const struct language_defn *language);
 549
 550 extern int val_print_string (CORE_ADDR addr, int len, int width,
 551                              struct ui_file *stream,
 552                              const struct value_print_options *options);
 553
 554 extern void print_variable_value (struct symbol *var,
 555                                   struct frame_info *frame,
 556                                   struct ui_file *stream);
 557
 558 extern int check_field (struct type *, const char *);
 559
 560 extern void typedef_print (struct type *type, struct symbol *news,
 561                            struct ui_file *stream);
 562
 563 extern char *internalvar_name (struct internalvar *var);
 564
 565 extern void preserve_values (struct objfile *);
 566
 567 /* From values.c */
 568
 569 extern struct value *value_copy (struct value *);
 570
 571 /* From valops.c */
 572
 573 extern struct value *varying_to_slice (struct value *);
 574
 575 extern struct value *value_slice (struct value *, int, int);
 576
 577 extern struct value *value_literal_complex (struct value *, struct value *,
 578                                             struct type *);
 579
 580 extern struct value *find_function_in_inferior (const char *,
 581                                                 struct objfile **);
 582
 583 extern struct value *value_allocate_space_in_inferior (int);
 584
 585 extern struct value *value_of_local (const char *name, int complain);
 586
 587 extern struct value * value_subscripted_rvalue (struct value *array, struct value *idx, int lowerbound);
 588 #endif /* !defined (VALUE_H) */