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, 2009 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 /* Set COMPONENT's location as appropriate for a component of WHOLE
 209    --- regardless of what kind of lvalue WHOLE is.  */
 210 extern void set_value_component_location (struct value *component,
 211                                           struct value *whole);
 212
 213 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 214    single value might have multiple LVALs), this hacked interface is
 215    limited to just the first PIECE.  Expect further change.  */
 216 /* Type of value; either not an lval, or one of the various different
 217    possible kinds of lval.  */
 218 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 219 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 220
 221 /* If lval == lval_memory, this is the address in the inferior.  If
 222    lval == lval_register, this is the byte offset into the registers
 223    structure.  */
 224 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 225 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 226
 227 /* Pointer to internal variable.  */
 228 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 229 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 230
 231 /* Frame register value is relative to.  This will be described in the
 232    lval enum above as "lval_register".  */
 233 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 234 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 235
 236 /* Register number if the value is from a register.  */
 237 extern short *deprecated_value_regnum_hack (struct value *);
 238 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 239
 240 /* Convert a REF to the object referenced.  */
 241
 242 extern struct value *coerce_ref (struct value *value);
 243
 244 /* If ARG is an array, convert it to a pointer.
 245    If ARG is a function, convert it to a function pointer.
 246
 247    References are dereferenced.  */
 248
 249 extern struct value *coerce_array (struct value *value);
 250
 251 /* Internal variables (variables for convenience of use of debugger)
 252    are recorded as a chain of these structures.  */
 253
 254 struct internalvar
 255 {
 256   struct internalvar *next;
 257   char *name;
 258   struct value *value;
 259   int endian;
 260 };
 261
 262 \f
 263
 264 #include "symtab.h"
 265 #include "gdbtypes.h"
 266 #include "expression.h"
 267
 268 struct frame_info;
 269 struct fn_field;
 270
 271 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 272
 273 extern LONGEST value_as_long (struct value *val);
 274 extern DOUBLEST value_as_double (struct value *val);
 275 extern CORE_ADDR value_as_address (struct value *val);
 276
 277 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
 278 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
 279                                int *invp);
 280 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
 281 extern LONGEST unpack_field_as_long (struct type *type,
 282                                      const gdb_byte *valaddr,
 283                                      int fieldno);
 284
 285 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
 286
 287 extern struct value *value_from_longest (struct type *type, LONGEST num);
 288 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 289 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 290 extern struct value *value_from_decfloat (struct type *type,
 291                                           const gdb_byte *decbytes);
 292 extern struct value *value_from_string (char *string);
 293
 294 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 295 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 296
 297 extern struct value *value_from_contents_and_address (struct type *,
 298                                                       const gdb_byte *,
 299                                                       CORE_ADDR);
 300
 301 extern struct value *default_value_from_register (struct type *type,
 302                                                   int regnum,
 303                                                   struct frame_info *frame);
 304
 305 extern struct value *value_from_register (struct type *type, int regnum,
 306                                           struct frame_info *frame);
 307
 308 extern CORE_ADDR address_from_register (struct type *type, int regnum,
 309                                         struct frame_info *frame);
 310
 311 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 312
 313 extern struct value *address_of_variable (struct symbol *var, struct block *b);
 314
 315 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 316
 317 struct value *value_of_register_lazy (struct frame_info *frame, int regnum);
 318
 319 extern int symbol_read_needs_frame (struct symbol *);
 320
 321 extern struct value *read_var_value (struct symbol *var,
 322                                      struct frame_info *frame);
 323
 324 extern struct value *allocate_value (struct type *type);
 325 extern struct value *allocate_value_lazy (struct type *type);
 326 extern void allocate_value_contents (struct value *value);
 327
 328 extern struct value *allocate_repeat_value (struct type *type, int count);
 329
 330 extern struct value *value_mark (void);
 331
 332 extern void value_free_to_mark (struct value *mark);
 333
 334 extern struct value *value_string (char *ptr, int len);
 335 extern struct value *value_bitstring (char *ptr, int len);
 336
 337 extern struct value *value_array (int lowbound, int highbound,
 338                                   struct value **elemvec);
 339
 340 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 341
 342 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 343                                   enum exp_opcode op);
 344
 345 extern struct value *value_ptradd (struct value *arg1, struct value *arg2);
 346
 347 extern struct value *value_ptrsub (struct value *arg1, struct value *arg2);
 348
 349 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2);
 350
 351 extern int value_must_coerce_to_target (struct value *arg1);
 352
 353 extern struct value *value_coerce_to_target (struct value *arg1);
 354
 355 extern struct value *value_coerce_array (struct value *arg1);
 356
 357 extern struct value *value_coerce_function (struct value *arg1);
 358
 359 extern struct value *value_ind (struct value *arg1);
 360
 361 extern struct value *value_addr (struct value *arg1);
 362
 363 extern struct value *value_ref (struct value *arg1);
 364
 365 extern struct value *value_assign (struct value *toval,
 366                                    struct value *fromval);
 367
 368 extern struct value *value_pos (struct value *arg1);
 369
 370 extern struct value *value_neg (struct value *arg1);
 371
 372 extern struct value *value_complement (struct value *arg1);
 373
 374 extern struct value *value_struct_elt (struct value **argp,
 375                                        struct value **args,
 376                                        char *name, int *static_memfuncp,
 377                                        char *err);
 378
 379 extern struct value *value_aggregate_elt (struct type *curtype,
 380                                           char *name,
 381                                           int want_address,
 382                                           enum noside noside);
 383
 384 extern struct value *value_static_field (struct type *type, int fieldno);
 385
 386 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 387                                                       int, int *,
 388                                                       struct type **, int *);
 389
 390 extern int find_overload_match (struct type **arg_types, int nargs,
 391                                 char *name, int method, int lax,
 392                                 struct value **objp, struct symbol *fsym,
 393                                 struct value **valp, struct symbol **symp,
 394                                 int *staticp);
 395
 396 extern struct value *value_field (struct value *arg1, int fieldno);
 397
 398 extern struct value *value_primitive_field (struct value *arg1, int offset,
 399                                             int fieldno,
 400                                             struct type *arg_type);
 401
 402
 403 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 404                                             int *);
 405
 406 extern struct value *value_full_object (struct value *, struct type *, int,
 407                                         int, int);
 408
 409 extern struct value *value_cast_pointers (struct type *, struct value *);
 410
 411 extern struct value *value_cast (struct type *type, struct value *arg2);
 412
 413 extern struct value *value_zero (struct type *type, enum lval_type lv);
 414
 415 extern struct value *value_one (struct type *type, enum lval_type lv);
 416
 417 extern struct value *value_repeat (struct value *arg1, int count);
 418
 419 extern struct value *value_subscript (struct value *array, struct value *idx);
 420
 421 extern struct value *value_bitstring_subscript (struct type *type,
 422                                                 struct value *bitstring,
 423                                                 struct value *idx);
 424
 425 extern struct value *register_value_being_returned (struct type *valtype,
 426                                                     struct regcache *retbuf);
 427
 428 extern int value_in (struct value *element, struct value *set);
 429
 430 extern int value_bit_index (struct type *type, const gdb_byte *addr,
 431                             int index);
 432
 433 extern int using_struct_return (struct type *func_type,
 434                                 struct type *value_type);
 435
 436 extern struct value *evaluate_expression (struct expression *exp);
 437
 438 extern struct value *evaluate_type (struct expression *exp);
 439
 440 extern struct value *evaluate_subexpression_type (struct expression *exp,
 441                                                   int subexp);
 442
 443 extern char *extract_field_op (struct expression *exp, int *subexp);
 444
 445 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 446                                                     int *, enum noside);
 447
 448 extern struct value *parse_and_eval (char *exp);
 449
 450 extern struct value *parse_to_comma_and_eval (char **expp);
 451
 452 extern struct type *parse_and_eval_type (char *p, int length);
 453
 454 extern CORE_ADDR parse_and_eval_address (char *exp);
 455
 456 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 457
 458 extern LONGEST parse_and_eval_long (char *exp);
 459
 460 extern void unop_promote (const struct language_defn *language,
 461                           struct gdbarch *gdbarch,
 462                           struct value **arg1);
 463
 464 extern void binop_promote (const struct language_defn *language,
 465                            struct gdbarch *gdbarch,
 466                            struct value **arg1, struct value **arg2);
 467
 468 extern struct value *access_value_history (int num);
 469
 470 extern struct value *value_of_internalvar (struct internalvar *var);
 471
 472 extern void set_internalvar (struct internalvar *var, struct value *val);
 473
 474 extern void set_internalvar_component (struct internalvar *var,
 475                                        int offset,
 476                                        int bitpos, int bitsize,
 477                                        struct value *newvalue);
 478
 479 extern struct internalvar *lookup_only_internalvar (char *name);
 480
 481 extern struct internalvar *create_internalvar (char *name);
 482
 483 extern struct internalvar *lookup_internalvar (char *name);
 484
 485 extern int value_equal (struct value *arg1, struct value *arg2);
 486
 487 extern int value_less (struct value *arg1, struct value *arg2);
 488
 489 extern int value_logical_not (struct value *arg1);
 490
 491 /* C++ */
 492
 493 extern struct value *value_of_this (int complain);
 494
 495 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 496                                     enum exp_opcode op,
 497                                     enum exp_opcode otherop,
 498                                     enum noside noside);
 499
 500 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 501                                    enum noside noside);
 502
 503 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 504                                      int j, struct type *type, int offset);
 505
 506 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 507                                  struct value *arg2);
 508
 509 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 510
 511 extern int destructor_name_p (const char *name, const struct type *type);
 512
 513 extern void value_free (struct value *val);
 514
 515 extern void free_all_values (void);
 516
 517 extern void release_value (struct value *val);
 518
 519 extern int record_latest_value (struct value *val);
 520
 521 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
 522                           int bitsize);
 523
 524 extern void type_print (struct type *type, char *varstring,
 525                         struct ui_file *stream, int show);
 526
 527 extern gdb_byte *baseclass_addr (struct type *type, int index,
 528                                  gdb_byte *valaddr,
 529                                  struct value **valuep, int *errp);
 530
 531 extern void print_longest (struct ui_file *stream, int format,
 532                            int use_local, LONGEST val);
 533
 534 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 535                             struct ui_file *stream);
 536
 537 extern void print_decimal_floating (const gdb_byte *valaddr, struct type *type,
 538                                     struct ui_file *stream);
 539
 540 extern int value_print (struct value *val, struct ui_file *stream,
 541                         const struct value_print_options *options);
 542
 543 extern void value_print_array_elements (struct value *val,
 544                                         struct ui_file *stream, int format,
 545                                         enum val_prettyprint pretty);
 546
 547 extern struct value *value_release_to_mark (struct value *mark);
 548
 549 extern int val_print (struct type *type, const gdb_byte *valaddr,
 550                       int embedded_offset, CORE_ADDR address,
 551                       struct ui_file *stream, int recurse,
 552                       const struct value_print_options *options,
 553                       const struct language_defn *language);
 554
 555 extern int common_val_print (struct value *val,
 556                              struct ui_file *stream, int recurse,
 557                              const struct value_print_options *options,
 558                              const struct language_defn *language);
 559
 560 extern int val_print_string (CORE_ADDR addr, int len, int width,
 561                              struct ui_file *stream,
 562                              const struct value_print_options *options);
 563
 564 extern void print_variable_and_value (const char *name,
 565                                       struct symbol *var,
 566                                       struct frame_info *frame,
 567                                       struct ui_file *stream,
 568                                       int indent);
 569
 570 extern int check_field (struct type *, const char *);
 571
 572 extern void typedef_print (struct type *type, struct symbol *news,
 573                            struct ui_file *stream);
 574
 575 extern char *internalvar_name (struct internalvar *var);
 576
 577 extern void preserve_values (struct objfile *);
 578
 579 /* From values.c */
 580
 581 extern struct value *value_copy (struct value *);
 582
 583 /* From valops.c */
 584
 585 extern struct value *varying_to_slice (struct value *);
 586
 587 extern struct value *value_slice (struct value *, int, int);
 588
 589 extern struct value *value_literal_complex (struct value *, struct value *,
 590                                             struct type *);
 591
 592 extern struct value *find_function_in_inferior (const char *,
 593                                                 struct objfile **);
 594
 595 extern struct value *value_allocate_space_in_inferior (int);
 596
 597 extern struct value *value_of_local (const char *name, int complain);
 598
 599 extern struct value * value_subscripted_rvalue (struct value *array, struct value *idx, int lowerbound);
 600 #endif /* !defined (VALUE_H) */