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