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