gdb/value.h

   1 /* Definitions for values of C expressions, for GDB.
   2
   3    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   4    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   5    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 2 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, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, USA.  */
  23
  24 #if !defined (VALUE_H)
  25 #define VALUE_H 1
  26
  27 #include "doublest.h"
  28 #include "frame.h"              /* For struct frame_id.  */
  29
  30 struct block;
  31 struct expression;
  32 struct regcache;
  33 struct symbol;
  34 struct type;
  35 struct ui_file;
  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 /* Values are stored in a chain, so that they can be deleted easily
  45    over calls to the inferior.  Values assigned to internal variables
  46    or put into the value history are taken off this list.  */
  47
  48 struct value *value_next (struct value *);
  49
  50 /* Type of the value.  */
  51
  52 extern struct type *value_type (struct value *);
  53
  54 /* This is being used to change the type of an existing value, that
  55    code should instead be creating a new value with the changed type
  56    (but possibly shared content).  */
  57
  58 extern void deprecated_set_value_type (struct value *value,
  59                                        struct type *type);
  60
  61 /* Only used for bitfields; number of bits contained in them.  */
  62
  63 extern int value_bitsize (struct value *);
  64 extern void set_value_bitsize (struct value *, int bit);
  65
  66 /* Only used for bitfields; position of start of field.  For
  67    BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.  For
  68    BITS_BIG_ENDIAN=1 targets, it is the position of the MSB.  */
  69
  70 extern int value_bitpos (struct value *);
  71 extern void set_value_bitpos (struct value *, int bit);
  72
  73 /* Describes offset of a value within lval of a structure in bytes.
  74    If lval == lval_memory, this is an offset to the address.  If lval
  75    == lval_register, this is a further offset from location.address
  76    within the registers structure.  Note also the member
  77    embedded_offset below.  */
  78
  79 extern int value_offset (struct value *);
  80 extern void set_value_offset (struct value *, int offset);
  81
  82 /* The comment from "struct value" reads: ``Is it modifiable?  Only
  83    relevant if lval != not_lval.''.  Shouldn't the value instead be
  84    not_lval and be done with it?  */
  85
  86 extern int deprecated_value_modifiable (struct value *value);
  87 extern void deprecated_set_value_modifiable (struct value *value,
  88                                              int modifiable);
  89
  90 /* If a value represents a C++ object, then the `type' field gives the
  91    object's compile-time type.  If the object actually belongs to some
  92    class derived from `type', perhaps with other base classes and
  93    additional members, then `type' is just a subobject of the real
  94    thing, and the full object is probably larger than `type' would
  95    suggest.
  96
  97    If `type' is a dynamic class (i.e. one with a vtable), then GDB can
  98    actually determine the object's run-time type by looking at the
  99    run-time type information in the vtable.  When this information is
 100    available, we may elect to read in the entire object, for several
 101    reasons:
 102
 103    - When printing the value, the user would probably rather see the
 104      full object, not just the limited portion apparent from the
 105      compile-time type.
 106
 107    - If `type' has virtual base classes, then even printing `type'
 108      alone may require reaching outside the `type' portion of the
 109      object to wherever the virtual base class has been stored.
 110
 111    When we store the entire object, `enclosing_type' is the run-time
 112    type -- the complete object -- and `embedded_offset' is the offset
 113    of `type' within that larger type, in bytes.  The value_contents()
 114    macro takes `embedded_offset' into account, so most GDB code
 115    continues to see the `type' portion of the value, just as the
 116    inferior would.
 117
 118    If `type' is a pointer to an object, then `enclosing_type' is a
 119    pointer to the object's run-time type, and `pointed_to_offset' is
 120    the offset in bytes from the full object to the pointed-to object
 121    -- that is, the value `embedded_offset' would have if we followed
 122    the pointer and fetched the complete object.  (I don't really see
 123    the point.  Why not just determine the run-time type when you
 124    indirect, and avoid the special case?  The contents don't matter
 125    until you indirect anyway.)
 126
 127    If we're not doing anything fancy, `enclosing_type' is equal to
 128    `type', and `embedded_offset' is zero, so everything works
 129    normally.  */
 130
 131 extern struct type *value_enclosing_type (struct value *);
 132 extern struct value *value_change_enclosing_type (struct value *val,
 133                                                   struct type *new_type);
 134 extern int value_pointed_to_offset (struct value *value);
 135 extern void set_value_pointed_to_offset (struct value *value, int val);
 136 extern int value_embedded_offset (struct value *value);
 137 extern void set_value_embedded_offset (struct value *value, int val);
 138
 139 /* If zero, contents of this value are in the contents field.  If
 140    nonzero, contents are in inferior memory at address in the
 141    location.address field plus the offset field (and the lval field
 142    should be lval_memory).
 143
 144    WARNING: This field is used by the code which handles watchpoints
 145    (see breakpoint.c) to decide whether a particular value can be
 146    watched by hardware watchpoints.  If the lazy flag is set for some
 147    member of a value chain, it is assumed that this member of the
 148    chain doesn't need to be watched as part of watching the value
 149    itself.  This is how GDB avoids watching the entire struct or array
 150    when the user wants to watch a single struct member or array
 151    element.  If you ever change the way lazy flag is set and reset, be
 152    sure to consider this use as well!  */
 153
 154 extern int value_lazy (struct value *);
 155 extern void set_value_lazy (struct value *value, int val);
 156
 157 /* value_contents() and value_contents_raw() both return the address
 158    of the gdb buffer used to hold a copy of the contents of the lval.
 159    value_contents() is used when the contents of the buffer are needed
 160    -- it uses value_fetch_lazy() to load the buffer from the process
 161    being debugged if it hasn't already been loaded
 162    (value_contents_writeable() is used when a writeable but fetched
 163    buffer is required)..  value_contents_raw() is used when data is
 164    being stored into the buffer, or when it is certain that the
 165    contents of the buffer are valid.
 166
 167    Note: The contents pointer is adjusted by the offset required to
 168    get to the real subobject, if the value happens to represent
 169    something embedded in a larger run-time object.  */
 170
 171 extern bfd_byte *value_contents_raw (struct value *);
 172
 173 /* Actual contents of the value.  For use of this value; setting it
 174    uses the stuff above.  Not valid if lazy is nonzero.  Target
 175    byte-order.  We force it to be aligned properly for any possible
 176    value.  Note that a value therefore extends beyond what is
 177    declared here.  */
 178
 179 extern const bfd_byte *value_contents (struct value *);
 180 extern bfd_byte *value_contents_writeable (struct value *);
 181
 182 /* The ALL variants of the above two macros do not adjust the returned
 183    pointer by the embedded_offset value.  */
 184
 185 extern bfd_byte *value_contents_all_raw (struct value *);
 186 extern const bfd_byte *value_contents_all (struct value *);
 187
 188 extern int value_fetch_lazy (struct value *val);
 189 extern int value_contents_equal (struct value *val1, struct value *val2);
 190
 191 /* If nonzero, this is the value of a variable which does not actually
 192    exist in the program.  */
 193 extern int value_optimized_out (struct value *value);
 194 extern void set_value_optimized_out (struct value *value, int val);
 195
 196 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 197    single value might have multiple LVALs), this hacked interface is
 198    limited to just the first PIECE.  Expect further change.  */
 199 /* Type of value; either not an lval, or one of the various different
 200    possible kinds of lval.  */
 201 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 202 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 203
 204 /* If lval == lval_memory, this is the address in the inferior.  If
 205    lval == lval_register, this is the byte offset into the registers
 206    structure.  */
 207 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 208 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 209
 210 /* Pointer to internal variable.  */
 211 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 212 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 213
 214 /* Frame register value is relative to.  This will be described in the
 215    lval enum above as "lval_register".  */
 216 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 217 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 218
 219 /* Register number if the value is from a register.  */
 220 extern short *deprecated_value_regnum_hack (struct value *);
 221 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 222
 223 /* Convert a REF to the object referenced.  */
 224
 225 extern struct value *coerce_ref (struct value *value);
 226
 227 /* If ARG is an array, convert it to a pointer.
 228    If ARG is an enum, convert it to an integer.
 229    If ARG is a function, convert it to a function pointer.
 230
 231    References are dereferenced.  */
 232
 233 extern struct value *coerce_array (struct value *value);
 234 extern struct value *coerce_number (struct value *value);
 235
 236 /* If ARG is an enum, convert it to an integer.  */
 237
 238 extern struct value *coerce_enum (struct value *value);
 239
 240 /* Internal variables (variables for convenience of use of debugger)
 241    are recorded as a chain of these structures.  */
 242
 243 struct internalvar
 244 {
 245   struct internalvar *next;
 246   char *name;
 247   struct value *value;
 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 char *valaddr);
 266 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 267                                int *invp);
 268 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 269 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 270                                      int fieldno);
 271
 272 extern struct value *value_from_longest (struct type *type, LONGEST num);
 273 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 274 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 275 extern struct value *value_from_string (char *string);
 276
 277 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 278 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 279
 280 extern struct value *value_from_register (struct type *type, int regnum,
 281                                           struct frame_info *frame);
 282
 283 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 284
 285 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 286
 287 extern int symbol_read_needs_frame (struct symbol *);
 288
 289 extern struct value *read_var_value (struct symbol *var,
 290                                      struct frame_info *frame);
 291
 292 extern struct value *locate_var_value (struct symbol *var,
 293                                        struct frame_info *frame);
 294
 295 extern struct value *allocate_value (struct type *type);
 296
 297 extern struct value *allocate_repeat_value (struct type *type, int count);
 298
 299 extern struct value *value_mark (void);
 300
 301 extern void value_free_to_mark (struct value *mark);
 302
 303 extern struct value *value_string (char *ptr, int len);
 304 extern struct value *value_bitstring (char *ptr, int len);
 305
 306 extern struct value *value_array (int lowbound, int highbound,
 307                                   struct value **elemvec);
 308
 309 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 310
 311 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 312                                   enum exp_opcode op);
 313
 314 extern struct value *value_add (struct value *arg1, struct value *arg2);
 315
 316 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 317
 318 extern struct value *value_coerce_array (struct value *arg1);
 319
 320 extern struct value *value_coerce_function (struct value *arg1);
 321
 322 extern struct value *value_ind (struct value *arg1);
 323
 324 extern struct value *value_addr (struct value *arg1);
 325
 326 extern struct value *value_assign (struct value *toval,
 327                                    struct value *fromval);
 328
 329 extern struct value *value_neg (struct value *arg1);
 330
 331 extern struct value *value_complement (struct value *arg1);
 332
 333 extern struct value *value_struct_elt (struct value **argp,
 334                                        struct value **args,
 335                                        char *name, int *static_memfuncp,
 336                                        char *err);
 337
 338 extern struct value *value_aggregate_elt (struct type *curtype,
 339                                           char *name, enum noside noside);
 340
 341 extern struct value *value_static_field (struct type *type, int fieldno);
 342
 343 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 344                                                       int, int *,
 345                                                       struct type **, int *);
 346
 347 extern int find_overload_match (struct type **arg_types, int nargs,
 348                                 char *name, int method, int lax,
 349                                 struct value **objp, struct symbol *fsym,
 350                                 struct value **valp, struct symbol **symp,
 351                                 int *staticp);
 352
 353 extern struct value *value_field (struct value *arg1, int fieldno);
 354
 355 extern struct value *value_primitive_field (struct value *arg1, int offset,
 356                                             int fieldno,
 357                                             struct type *arg_type);
 358
 359
 360 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 361                                             int *);
 362
 363 extern struct value *value_full_object (struct value *, struct type *, int,
 364                                         int, int);
 365
 366 extern struct value *value_cast (struct type *type, struct value *arg2);
 367
 368 extern struct value *value_zero (struct type *type, enum lval_type lv);
 369
 370 extern struct value *value_repeat (struct value *arg1, int count);
 371
 372 extern struct value *value_subscript (struct value *array, struct value *idx);
 373
 374 extern struct value *register_value_being_returned (struct type *valtype,
 375                                                     struct regcache *retbuf);
 376
 377 extern struct value *value_in (struct value *element, struct value *set);
 378
 379 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 380                             int index);
 381
 382 extern int using_struct_return (struct type *value_type, int gcc_p);
 383
 384 extern struct value *evaluate_expression (struct expression *exp);
 385
 386 extern struct value *evaluate_type (struct expression *exp);
 387
 388 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 389                                                     int *, enum noside);
 390
 391 extern struct value *parse_and_eval (char *exp);
 392
 393 extern struct value *parse_to_comma_and_eval (char **expp);
 394
 395 extern struct type *parse_and_eval_type (char *p, int length);
 396
 397 extern CORE_ADDR parse_and_eval_address (char *exp);
 398
 399 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 400
 401 extern LONGEST parse_and_eval_long (char *exp);
 402
 403 extern struct value *access_value_history (int num);
 404
 405 extern struct value *value_of_internalvar (struct internalvar *var);
 406
 407 extern void set_internalvar (struct internalvar *var, struct value *val);
 408
 409 extern void set_internalvar_component (struct internalvar *var,
 410                                        int offset,
 411                                        int bitpos, int bitsize,
 412                                        struct value *newvalue);
 413
 414 extern struct internalvar *lookup_internalvar (char *name);
 415
 416 extern int value_equal (struct value *arg1, struct value *arg2);
 417
 418 extern int value_less (struct value *arg1, struct value *arg2);
 419
 420 extern int value_logical_not (struct value *arg1);
 421
 422 /* C++ */
 423
 424 extern struct value *value_of_this (int complain);
 425
 426 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 427                                     enum exp_opcode op,
 428                                     enum exp_opcode otherop,
 429                                     enum noside noside);
 430
 431 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 432                                    enum noside noside);
 433
 434 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 435                                      int j, struct type *type, int offset);
 436
 437 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 438                                  struct value *arg2);
 439
 440 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 441
 442 extern int destructor_name_p (const char *name, const struct type *type);
 443
 444 #define value_free(val) xfree (val)
 445
 446 extern void free_all_values (void);
 447
 448 extern void release_value (struct value *val);
 449
 450 extern int record_latest_value (struct value *val);
 451
 452 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 453                           int bitsize);
 454
 455 extern void type_print (struct type *type, char *varstring,
 456                         struct ui_file *stream, int show);
 457
 458 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 459                              struct value **valuep, int *errp);
 460
 461 extern void print_longest (struct ui_file *stream, int format,
 462                            int use_local, LONGEST val);
 463
 464 extern void print_floating (const bfd_byte *valaddr, struct type *type,
 465                             struct ui_file *stream);
 466
 467 extern int value_print (struct value *val, struct ui_file *stream, int format,
 468                         enum val_prettyprint pretty);
 469
 470 extern void value_print_array_elements (struct value *val,
 471                                         struct ui_file *stream, int format,
 472                                         enum val_prettyprint pretty);
 473
 474 extern struct value *value_release_to_mark (struct value *mark);
 475
 476 extern int val_print (struct type *type, const bfd_byte *valaddr,
 477                       int embedded_offset, CORE_ADDR address,
 478                       struct ui_file *stream, int format,
 479                       int deref_ref, int recurse,
 480                       enum val_prettyprint pretty);
 481
 482 extern int val_print_string (CORE_ADDR addr, int len, int width,
 483                              struct ui_file *stream);
 484
 485 extern void print_variable_value (struct symbol *var,
 486                                   struct frame_info *frame,
 487                                   struct ui_file *stream);
 488
 489 extern int check_field (struct value *, const char *);
 490
 491 extern void typedef_print (struct type *type, struct symbol *news,
 492                            struct ui_file *stream);
 493
 494 extern char *internalvar_name (struct internalvar *var);
 495
 496 extern void clear_value_history (void);
 497
 498 extern void clear_internalvars (void);
 499
 500 /* From values.c */
 501
 502 extern struct value *value_copy (struct value *);
 503
 504 /* From valops.c */
 505
 506 extern struct value *varying_to_slice (struct value *);
 507
 508 extern struct value *value_slice (struct value *, int, int);
 509
 510 extern struct value *value_literal_complex (struct value *, struct value *,
 511                                             struct type *);
 512
 513 extern void find_rt_vbase_offset (struct type *, struct type *,
 514                                   const bfd_byte *, int, int *, int *);
 515
 516 extern struct value *find_function_in_inferior (const char *);
 517
 518 extern struct value *value_allocate_space_in_inferior (int);
 519
 520 extern struct value *value_of_local (const char *name, int complain);
 521
 522 #endif /* !defined (VALUE_H) */