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
 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 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 196    single value might have multiple LVALs), this hacked interface is
 197    limited to just the first PIECE.  Expect further change.  */
 198 /* Type of value; either not an lval, or one of the various different
 199    possible kinds of lval.  */
 200 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 201 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 202
 203 /* If lval == lval_memory, this is the address in the inferior.  If
 204    lval == lval_register, this is the byte offset into the registers
 205    structure.  */
 206 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 207 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 208
 209 /* Pointer to internal variable.  */
 210 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 211 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 212
 213 /* Frame register value is relative to.  This will be described in the
 214    lval enum above as "lval_register".  */
 215 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 216 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 217
 218 /* Register number if the value is from a register.  */
 219 extern short *deprecated_value_regnum_hack (struct value *);
 220 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 221
 222 /* Convert a REF to the object referenced.  */
 223
 224 extern struct value *coerce_ref (struct value *value);
 225
 226 /* If ARG is an array, convert it to a pointer.
 227    If ARG is an enum, convert it to an integer.
 228    If ARG is a function, convert it to a function pointer.
 229
 230    References are dereferenced.  */
 231
 232 extern struct value *coerce_array (struct value *value);
 233 extern struct value *coerce_number (struct value *value);
 234
 235 /* If ARG is an enum, convert it to an integer.  */
 236
 237 extern struct value *coerce_enum (struct value *value);
 238
 239 /* Internal variables (variables for convenience of use of debugger)
 240    are recorded as a chain of these structures.  */
 241
 242 struct internalvar
 243 {
 244   struct internalvar *next;
 245   char *name;
 246   struct value *value;
 247 };
 248
 249 \f
 250
 251 #include "symtab.h"
 252 #include "gdbtypes.h"
 253 #include "expression.h"
 254
 255 struct frame_info;
 256 struct fn_field;
 257
 258 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 259
 260 extern LONGEST value_as_long (struct value *val);
 261 extern DOUBLEST value_as_double (struct value *val);
 262 extern CORE_ADDR value_as_address (struct value *val);
 263
 264 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 265 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 266                                int *invp);
 267 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 268 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 269                                      int fieldno);
 270
 271 extern struct value *value_from_longest (struct type *type, LONGEST num);
 272 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 273 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 274 extern struct value *value_from_string (char *string);
 275
 276 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 277 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 278
 279 extern struct value *value_from_register (struct type *type, int regnum,
 280                                           struct frame_info *frame);
 281
 282 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 283
 284 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 285
 286 extern int symbol_read_needs_frame (struct symbol *);
 287
 288 extern struct value *read_var_value (struct symbol *var,
 289                                      struct frame_info *frame);
 290
 291 extern struct value *locate_var_value (struct symbol *var,
 292                                        struct frame_info *frame);
 293
 294 extern struct value *allocate_value (struct type *type);
 295
 296 extern struct value *allocate_repeat_value (struct type *type, int count);
 297
 298 extern struct value *value_mark (void);
 299
 300 extern void value_free_to_mark (struct value *mark);
 301
 302 extern struct value *value_string (char *ptr, int len);
 303 extern struct value *value_bitstring (char *ptr, int len);
 304
 305 extern struct value *value_array (int lowbound, int highbound,
 306                                   struct value **elemvec);
 307
 308 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 309
 310 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 311                                   enum exp_opcode op);
 312
 313 extern struct value *value_add (struct value *arg1, struct value *arg2);
 314
 315 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 316
 317 extern struct value *value_coerce_array (struct value *arg1);
 318
 319 extern struct value *value_coerce_function (struct value *arg1);
 320
 321 extern struct value *value_ind (struct value *arg1);
 322
 323 extern struct value *value_addr (struct value *arg1);
 324
 325 extern struct value *value_assign (struct value *toval,
 326                                    struct value *fromval);
 327
 328 extern struct value *value_neg (struct value *arg1);
 329
 330 extern struct value *value_complement (struct value *arg1);
 331
 332 extern struct value *value_struct_elt (struct value **argp,
 333                                        struct value **args,
 334                                        char *name, int *static_memfuncp,
 335                                        char *err);
 336
 337 extern struct value *value_aggregate_elt (struct type *curtype,
 338                                           char *name, enum noside noside);
 339
 340 extern struct value *value_static_field (struct type *type, int fieldno);
 341
 342 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 343                                                       int, int *,
 344                                                       struct type **, int *);
 345
 346 extern int find_overload_match (struct type **arg_types, int nargs,
 347                                 char *name, int method, int lax,
 348                                 struct value **objp, struct symbol *fsym,
 349                                 struct value **valp, struct symbol **symp,
 350                                 int *staticp);
 351
 352 extern struct value *value_field (struct value *arg1, int fieldno);
 353
 354 extern struct value *value_primitive_field (struct value *arg1, int offset,
 355                                             int fieldno,
 356                                             struct type *arg_type);
 357
 358
 359 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 360                                             int *);
 361
 362 extern struct value *value_full_object (struct value *, struct type *, int,
 363                                         int, int);
 364
 365 extern struct value *value_cast (struct type *type, struct value *arg2);
 366
 367 extern struct value *value_zero (struct type *type, enum lval_type lv);
 368
 369 extern struct value *value_repeat (struct value *arg1, int count);
 370
 371 extern struct value *value_subscript (struct value *array, struct value *idx);
 372
 373 extern struct value *register_value_being_returned (struct type *valtype,
 374                                                     struct regcache *retbuf);
 375
 376 extern struct value *value_in (struct value *element, struct value *set);
 377
 378 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 379                             int index);
 380
 381 extern int using_struct_return (struct type *value_type, int gcc_p);
 382
 383 extern struct value *evaluate_expression (struct expression *exp);
 384
 385 extern struct value *evaluate_type (struct expression *exp);
 386
 387 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 388                                                     int *, enum noside);
 389
 390 extern struct value *parse_and_eval (char *exp);
 391
 392 extern struct value *parse_to_comma_and_eval (char **expp);
 393
 394 extern struct type *parse_and_eval_type (char *p, int length);
 395
 396 extern CORE_ADDR parse_and_eval_address (char *exp);
 397
 398 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 399
 400 extern LONGEST parse_and_eval_long (char *exp);
 401
 402 extern struct value *access_value_history (int num);
 403
 404 extern struct value *value_of_internalvar (struct internalvar *var);
 405
 406 extern void set_internalvar (struct internalvar *var, struct value *val);
 407
 408 extern void set_internalvar_component (struct internalvar *var,
 409                                        int offset,
 410                                        int bitpos, int bitsize,
 411                                        struct value *newvalue);
 412
 413 extern struct internalvar *lookup_internalvar (char *name);
 414
 415 extern int value_equal (struct value *arg1, struct value *arg2);
 416
 417 extern int value_less (struct value *arg1, struct value *arg2);
 418
 419 extern int value_logical_not (struct value *arg1);
 420
 421 /* C++ */
 422
 423 extern struct value *value_of_this (int complain);
 424
 425 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 426                                     enum exp_opcode op,
 427                                     enum exp_opcode otherop,
 428                                     enum noside noside);
 429
 430 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 431                                    enum noside noside);
 432
 433 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 434                                      int j, struct type *type, int offset);
 435
 436 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 437                                  struct value *arg2);
 438
 439 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 440
 441 extern int destructor_name_p (const char *name, const struct type *type);
 442
 443 #define value_free(val) xfree (val)
 444
 445 extern void free_all_values (void);
 446
 447 extern void release_value (struct value *val);
 448
 449 extern int record_latest_value (struct value *val);
 450
 451 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 452                           int bitsize);
 453
 454 extern void type_print (struct type *type, char *varstring,
 455                         struct ui_file *stream, int show);
 456
 457 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 458                              struct value **valuep, int *errp);
 459
 460 extern void print_longest (struct ui_file *stream, int format,
 461                            int use_local, LONGEST val);
 462
 463 extern void print_floating (const bfd_byte *valaddr, struct type *type,
 464                             struct ui_file *stream);
 465
 466 extern int value_print (struct value *val, struct ui_file *stream, int format,
 467                         enum val_prettyprint pretty);
 468
 469 extern void value_print_array_elements (struct value *val,
 470                                         struct ui_file *stream, int format,
 471                                         enum val_prettyprint pretty);
 472
 473 extern struct value *value_release_to_mark (struct value *mark);
 474
 475 extern int val_print (struct type *type, const bfd_byte *valaddr,
 476                       int embedded_offset, CORE_ADDR address,
 477                       struct ui_file *stream, int format,
 478                       int deref_ref, int recurse,
 479                       enum val_prettyprint pretty);
 480
 481 extern int val_print_string (CORE_ADDR addr, int len, int width,
 482                              struct ui_file *stream);
 483
 484 extern void print_variable_value (struct symbol *var,
 485                                   struct frame_info *frame,
 486                                   struct ui_file *stream);
 487
 488 extern int check_field (struct value *, const char *);
 489
 490 extern void typedef_print (struct type *type, struct symbol *news,
 491                            struct ui_file *stream);
 492
 493 extern char *internalvar_name (struct internalvar *var);
 494
 495 extern void clear_value_history (void);
 496
 497 extern void clear_internalvars (void);
 498
 499 /* From values.c */
 500
 501 extern struct value *value_copy (struct value *);
 502
 503 /* From valops.c */
 504
 505 extern struct value *varying_to_slice (struct value *);
 506
 507 extern struct value *value_slice (struct value *, int, int);
 508
 509 extern struct value *value_literal_complex (struct value *, struct value *,
 510                                             struct type *);
 511
 512 extern void find_rt_vbase_offset (struct type *, struct type *,
 513                                   const bfd_byte *, int, int *, int *);
 514
 515 extern struct value *find_function_in_inferior (const char *);
 516
 517 extern struct value *value_allocate_space_in_inferior (int);
 518
 519 extern struct value *value_of_local (const char *name, int complain);
 520
 521 #endif /* !defined (VALUE_H) */