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 an enum, convert it to an integer.
 234    If ARG is a function, convert it to a function pointer.
 235
 236    References are dereferenced.  */
 237
 238 extern struct value *coerce_array (struct value *value);
 239 extern struct value *coerce_number (struct value *value);
 240
 241 /* If ARG is an enum, convert it to an integer.  */
 242
 243 extern struct value *coerce_enum (struct value *value);
 244
 245 /* Internal variables (variables for convenience of use of debugger)
 246    are recorded as a chain of these structures.  */
 247
 248 struct internalvar
 249 {
 250   struct internalvar *next;
 251   char *name;
 252   struct value *value;
 253   int endian;
 254 };
 255
 256 \f
 257
 258 #include "symtab.h"
 259 #include "gdbtypes.h"
 260 #include "expression.h"
 261
 262 struct frame_info;
 263 struct fn_field;
 264
 265 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 266
 267 extern LONGEST value_as_long (struct value *val);
 268 extern DOUBLEST value_as_double (struct value *val);
 269 extern CORE_ADDR value_as_address (struct value *val);
 270
 271 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
 272 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
 273                                int *invp);
 274 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
 275 extern LONGEST unpack_field_as_long (struct type *type,
 276                                      const gdb_byte *valaddr,
 277                                      int fieldno);
 278
 279 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
 280
 281 extern struct value *value_from_longest (struct type *type, LONGEST num);
 282 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 283 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 284 extern struct value *value_from_decfloat (struct type *type,
 285                                           const gdb_byte *decbytes);
 286 extern struct value *value_from_string (char *string);
 287
 288 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 289 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 290
 291 extern struct value *default_value_from_register (struct type *type,
 292                                                   int regnum,
 293                                                   struct frame_info *frame);
 294
 295 extern struct value *value_from_register (struct type *type, int regnum,
 296                                           struct frame_info *frame);
 297
 298 extern CORE_ADDR address_from_register (struct type *type, int regnum,
 299                                         struct frame_info *frame);
 300
 301 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 302
 303 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 304
 305 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
 306
 307 extern int symbol_read_needs_frame (struct symbol *);
 308
 309 extern struct value *read_var_value (struct symbol *var,
 310                                      struct frame_info *frame);
 311
 312 extern struct value *locate_var_value (struct symbol *var,
 313                                        struct frame_info *frame);
 314
 315 extern struct value *allocate_value (struct type *type);
 316
 317 extern struct value *allocate_repeat_value (struct type *type, int count);
 318
 319 extern struct value *value_mark (void);
 320
 321 extern void value_free_to_mark (struct value *mark);
 322
 323 extern struct value *value_string (char *ptr, int len);
 324 extern struct value *value_bitstring (char *ptr, int len);
 325
 326 extern struct value *value_array (int lowbound, int highbound,
 327                                   struct value **elemvec);
 328
 329 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 330
 331 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 332                                   enum exp_opcode op);
 333
 334 extern struct value *value_add (struct value *arg1, struct value *arg2);
 335
 336 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 337
 338 extern int value_must_coerce_to_target (struct value *arg1);
 339
 340 extern struct value *value_coerce_to_target (struct value *arg1);
 341
 342 extern struct value *value_coerce_array (struct value *arg1);
 343
 344 extern struct value *value_coerce_function (struct value *arg1);
 345
 346 extern struct value *value_ind (struct value *arg1);
 347
 348 extern struct value *value_addr (struct value *arg1);
 349
 350 extern struct value *value_ref (struct value *arg1);
 351
 352 extern struct value *value_assign (struct value *toval,
 353                                    struct value *fromval);
 354
 355 extern struct value *value_pos (struct value *arg1);
 356
 357 extern struct value *value_neg (struct value *arg1);
 358
 359 extern struct value *value_complement (struct value *arg1);
 360
 361 extern struct value *value_struct_elt (struct value **argp,
 362                                        struct value **args,
 363                                        char *name, int *static_memfuncp,
 364                                        char *err);
 365
 366 extern struct value *value_aggregate_elt (struct type *curtype,
 367                                           char *name,
 368                                           int want_address,
 369                                           enum noside noside);
 370
 371 extern struct value *value_static_field (struct type *type, int fieldno);
 372
 373 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 374                                                       int, int *,
 375                                                       struct type **, int *);
 376
 377 extern int find_overload_match (struct type **arg_types, int nargs,
 378                                 char *name, int method, int lax,
 379                                 struct value **objp, struct symbol *fsym,
 380                                 struct value **valp, struct symbol **symp,
 381                                 int *staticp);
 382
 383 extern struct value *value_field (struct value *arg1, int fieldno);
 384
 385 extern struct value *value_primitive_field (struct value *arg1, int offset,
 386                                             int fieldno,
 387                                             struct type *arg_type);
 388
 389
 390 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 391                                             int *);
 392
 393 extern struct value *value_full_object (struct value *, struct type *, int,
 394                                         int, int);
 395
 396 extern struct value *value_cast_pointers (struct type *, struct value *);
 397
 398 extern struct value *value_cast (struct type *type, struct value *arg2);
 399
 400 extern struct value *value_zero (struct type *type, enum lval_type lv);
 401
 402 extern struct value *value_one (struct type *type, enum lval_type lv);
 403
 404 extern struct value *value_repeat (struct value *arg1, int count);
 405
 406 extern struct value *value_subscript (struct value *array, struct value *idx);
 407
 408 extern struct value *value_bitstring_subscript (struct type *type,
 409                                                 struct value *bitstring,
 410                                                 struct value *idx);
 411
 412 extern struct value *register_value_being_returned (struct type *valtype,
 413                                                     struct regcache *retbuf);
 414
 415 extern struct value *value_in (struct value *element, struct value *set);
 416
 417 extern int value_bit_index (struct type *type, const gdb_byte *addr,
 418                             int index);
 419
 420 extern int using_struct_return (struct type *func_type,
 421                                 struct type *value_type);
 422
 423 extern struct value *evaluate_expression (struct expression *exp);
 424
 425 extern struct value *evaluate_type (struct expression *exp);
 426
 427 extern struct value *evaluate_subexpression_type (struct expression *exp,
 428                                                   int subexp);
 429
 430 extern char *extract_field_op (struct expression *exp, int *subexp);
 431
 432 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 433                                                     int *, enum noside);
 434
 435 extern struct value *parse_and_eval (char *exp);
 436
 437 extern struct value *parse_to_comma_and_eval (char **expp);
 438
 439 extern struct type *parse_and_eval_type (char *p, int length);
 440
 441 extern CORE_ADDR parse_and_eval_address (char *exp);
 442
 443 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 444
 445 extern LONGEST parse_and_eval_long (char *exp);
 446
 447 extern struct value *access_value_history (int num);
 448
 449 extern struct value *value_of_internalvar (struct internalvar *var);
 450
 451 extern void set_internalvar (struct internalvar *var, struct value *val);
 452
 453 extern void set_internalvar_component (struct internalvar *var,
 454                                        int offset,
 455                                        int bitpos, int bitsize,
 456                                        struct value *newvalue);
 457
 458 extern struct internalvar *lookup_only_internalvar (char *name);
 459
 460 extern struct internalvar *create_internalvar (char *name);
 461
 462 extern struct internalvar *lookup_internalvar (char *name);
 463
 464 extern int value_equal (struct value *arg1, struct value *arg2);
 465
 466 extern int value_less (struct value *arg1, struct value *arg2);
 467
 468 extern int value_logical_not (struct value *arg1);
 469
 470 /* C++ */
 471
 472 extern struct value *value_of_this (int complain);
 473
 474 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 475                                     enum exp_opcode op,
 476                                     enum exp_opcode otherop,
 477                                     enum noside noside);
 478
 479 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 480                                    enum noside noside);
 481
 482 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 483                                      int j, struct type *type, int offset);
 484
 485 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 486                                  struct value *arg2);
 487
 488 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 489
 490 extern int destructor_name_p (const char *name, const struct type *type);
 491
 492 #define value_free(val) xfree (val)
 493
 494 extern void free_all_values (void);
 495
 496 extern void release_value (struct value *val);
 497
 498 extern int record_latest_value (struct value *val);
 499
 500 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
 501                           int bitsize);
 502
 503 extern void type_print (struct type *type, char *varstring,
 504                         struct ui_file *stream, int show);
 505
 506 extern gdb_byte *baseclass_addr (struct type *type, int index,
 507                                  gdb_byte *valaddr,
 508                                  struct value **valuep, int *errp);
 509
 510 extern void print_longest (struct ui_file *stream, int format,
 511                            int use_local, LONGEST val);
 512
 513 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 514                             struct ui_file *stream);
 515
 516 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
 517                                     struct ui_file *stream);
 518
 519 extern int value_print (struct value *val, struct ui_file *stream, int format,
 520                         enum val_prettyprint pretty);
 521
 522 extern void value_print_array_elements (struct value *val,
 523                                         struct ui_file *stream, int format,
 524                                         enum val_prettyprint pretty);
 525
 526 extern struct value *value_release_to_mark (struct value *mark);
 527
 528 extern int val_print (struct type *type, const gdb_byte *valaddr,
 529                       int embedded_offset, CORE_ADDR address,
 530                       struct ui_file *stream, int format,
 531                       int deref_ref, int recurse,
 532                       enum val_prettyprint pretty,
 533                       const struct language_defn *language);
 534
 535 extern int common_val_print (struct value *val,
 536                              struct ui_file *stream, int format,
 537                              int deref_ref, int recurse,
 538                              enum val_prettyprint pretty,
 539                              const struct language_defn *language);
 540
 541 extern int val_print_string (CORE_ADDR addr, int len, int width,
 542                              struct ui_file *stream);
 543
 544 extern void print_variable_value (struct symbol *var,
 545                                   struct frame_info *frame,
 546                                   struct ui_file *stream);
 547
 548 extern int check_field (struct type *, const char *);
 549
 550 extern void typedef_print (struct type *type, struct symbol *news,
 551                            struct ui_file *stream);
 552
 553 extern char *internalvar_name (struct internalvar *var);
 554
 555 extern void preserve_values (struct objfile *);
 556
 557 /* From values.c */
 558
 559 extern struct value *value_copy (struct value *);
 560
 561 /* From valops.c */
 562
 563 extern struct value *varying_to_slice (struct value *);
 564
 565 extern struct value *value_slice (struct value *, int, int);
 566
 567 extern struct value *value_literal_complex (struct value *, struct value *,
 568                                             struct type *);
 569
 570 extern struct value *find_function_in_inferior (const char *);
 571
 572 extern struct value *value_allocate_space_in_inferior (int);
 573
 574 extern struct value *value_of_local (const char *name, int complain);
 575
 576 extern struct value * value_subscripted_rvalue (struct value *array, struct value *idx, int lowerbound);
 577 #endif /* !defined (VALUE_H) */