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 /* Pointer to member function.  Depends on compiler implementation.  */
 250
 251 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 252 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 253 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 254 \f
 255
 256 #include "symtab.h"
 257 #include "gdbtypes.h"
 258 #include "expression.h"
 259
 260 struct frame_info;
 261 struct fn_field;
 262
 263 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 264
 265 extern LONGEST value_as_long (struct value *val);
 266 extern DOUBLEST value_as_double (struct value *val);
 267 extern CORE_ADDR value_as_address (struct value *val);
 268
 269 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 270 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 271                                int *invp);
 272 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 273 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 274                                      int fieldno);
 275
 276 extern struct value *value_from_longest (struct type *type, LONGEST num);
 277 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 278 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 279 extern struct value *value_from_string (char *string);
 280
 281 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 282 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 283
 284 extern struct value *value_from_register (struct type *type, int regnum,
 285                                           struct frame_info *frame);
 286
 287 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 288
 289 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 290
 291 extern int symbol_read_needs_frame (struct symbol *);
 292
 293 extern struct value *read_var_value (struct symbol *var,
 294                                      struct frame_info *frame);
 295
 296 extern struct value *locate_var_value (struct symbol *var,
 297                                        struct frame_info *frame);
 298
 299 extern struct value *allocate_value (struct type *type);
 300
 301 extern struct value *allocate_repeat_value (struct type *type, int count);
 302
 303 extern struct value *value_mark (void);
 304
 305 extern void value_free_to_mark (struct value *mark);
 306
 307 extern struct value *value_string (char *ptr, int len);
 308 extern struct value *value_bitstring (char *ptr, int len);
 309
 310 extern struct value *value_array (int lowbound, int highbound,
 311                                   struct value **elemvec);
 312
 313 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 314
 315 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 316                                   enum exp_opcode op);
 317
 318 extern struct value *value_add (struct value *arg1, struct value *arg2);
 319
 320 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 321
 322 extern struct value *value_coerce_array (struct value *arg1);
 323
 324 extern struct value *value_coerce_function (struct value *arg1);
 325
 326 extern struct value *value_ind (struct value *arg1);
 327
 328 extern struct value *value_addr (struct value *arg1);
 329
 330 extern struct value *value_assign (struct value *toval,
 331                                    struct value *fromval);
 332
 333 extern struct value *value_neg (struct value *arg1);
 334
 335 extern struct value *value_complement (struct value *arg1);
 336
 337 extern struct value *value_struct_elt (struct value **argp,
 338                                        struct value **args,
 339                                        char *name, int *static_memfuncp,
 340                                        char *err);
 341
 342 extern struct value *value_aggregate_elt (struct type *curtype,
 343                                           char *name, enum noside noside);
 344
 345 extern struct value *value_static_field (struct type *type, int fieldno);
 346
 347 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 348                                                       int, int *,
 349                                                       struct type **, int *);
 350
 351 extern int find_overload_match (struct type **arg_types, int nargs,
 352                                 char *name, int method, int lax,
 353                                 struct value **objp, struct symbol *fsym,
 354                                 struct value **valp, struct symbol **symp,
 355                                 int *staticp);
 356
 357 extern struct value *value_field (struct value *arg1, int fieldno);
 358
 359 extern struct value *value_primitive_field (struct value *arg1, int offset,
 360                                             int fieldno,
 361                                             struct type *arg_type);
 362
 363
 364 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 365                                             int *);
 366
 367 extern struct value *value_full_object (struct value *, struct type *, int,
 368                                         int, int);
 369
 370 extern struct value *value_cast (struct type *type, struct value *arg2);
 371
 372 extern struct value *value_zero (struct type *type, enum lval_type lv);
 373
 374 extern struct value *value_repeat (struct value *arg1, int count);
 375
 376 extern struct value *value_subscript (struct value *array, struct value *idx);
 377
 378 extern struct value *register_value_being_returned (struct type *valtype,
 379                                                     struct regcache *retbuf);
 380
 381 extern struct value *value_in (struct value *element, struct value *set);
 382
 383 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 384                             int index);
 385
 386 extern int using_struct_return (struct type *value_type, int gcc_p);
 387
 388 extern struct value *evaluate_expression (struct expression *exp);
 389
 390 extern struct value *evaluate_type (struct expression *exp);
 391
 392 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 393                                                     int *, enum noside);
 394
 395 extern struct value *parse_and_eval (char *exp);
 396
 397 extern struct value *parse_to_comma_and_eval (char **expp);
 398
 399 extern struct type *parse_and_eval_type (char *p, int length);
 400
 401 extern CORE_ADDR parse_and_eval_address (char *exp);
 402
 403 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 404
 405 extern LONGEST parse_and_eval_long (char *exp);
 406
 407 extern struct value *access_value_history (int num);
 408
 409 extern struct value *value_of_internalvar (struct internalvar *var);
 410
 411 extern void set_internalvar (struct internalvar *var, struct value *val);
 412
 413 extern void set_internalvar_component (struct internalvar *var,
 414                                        int offset,
 415                                        int bitpos, int bitsize,
 416                                        struct value *newvalue);
 417
 418 extern struct internalvar *lookup_internalvar (char *name);
 419
 420 extern int value_equal (struct value *arg1, struct value *arg2);
 421
 422 extern int value_less (struct value *arg1, struct value *arg2);
 423
 424 extern int value_logical_not (struct value *arg1);
 425
 426 /* C++ */
 427
 428 extern struct value *value_of_this (int complain);
 429
 430 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 431                                     enum exp_opcode op,
 432                                     enum exp_opcode otherop,
 433                                     enum noside noside);
 434
 435 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 436                                    enum noside noside);
 437
 438 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 439                                      int j, struct type *type, int offset);
 440
 441 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 442                                  struct value *arg2);
 443
 444 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 445
 446 extern int destructor_name_p (const char *name, const struct type *type);
 447
 448 #define value_free(val) xfree (val)
 449
 450 extern void free_all_values (void);
 451
 452 extern void release_value (struct value *val);
 453
 454 extern int record_latest_value (struct value *val);
 455
 456 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 457                           int bitsize);
 458
 459 extern void type_print (struct type *type, char *varstring,
 460                         struct ui_file *stream, int show);
 461
 462 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 463                              struct value **valuep, int *errp);
 464
 465 extern void print_longest (struct ui_file *stream, int format,
 466                            int use_local, LONGEST val);
 467
 468 extern void print_floating (const bfd_byte *valaddr, struct type *type,
 469                             struct ui_file *stream);
 470
 471 extern int value_print (struct value *val, struct ui_file *stream, int format,
 472                         enum val_prettyprint pretty);
 473
 474 extern void value_print_array_elements (struct value *val,
 475                                         struct ui_file *stream, int format,
 476                                         enum val_prettyprint pretty);
 477
 478 extern struct value *value_release_to_mark (struct value *mark);
 479
 480 extern int val_print (struct type *type, const bfd_byte *valaddr,
 481                       int embedded_offset, CORE_ADDR address,
 482                       struct ui_file *stream, int format,
 483                       int deref_ref, int recurse,
 484                       enum val_prettyprint pretty);
 485
 486 extern int val_print_string (CORE_ADDR addr, int len, int width,
 487                              struct ui_file *stream);
 488
 489 extern void print_variable_value (struct symbol *var,
 490                                   struct frame_info *frame,
 491                                   struct ui_file *stream);
 492
 493 extern int check_field (struct value *, const char *);
 494
 495 extern void typedef_print (struct type *type, struct symbol *news,
 496                            struct ui_file *stream);
 497
 498 extern char *internalvar_name (struct internalvar *var);
 499
 500 extern void clear_value_history (void);
 501
 502 extern void clear_internalvars (void);
 503
 504 /* From values.c */
 505
 506 extern struct value *value_copy (struct value *);
 507
 508 /* From valops.c */
 509
 510 extern struct value *varying_to_slice (struct value *);
 511
 512 extern struct value *value_slice (struct value *, int, int);
 513
 514 extern struct value *value_literal_complex (struct value *, struct value *,
 515                                             struct type *);
 516
 517 extern void find_rt_vbase_offset (struct type *, struct type *,
 518                                   const bfd_byte *, int, int *, int *);
 519
 520 extern struct value *find_function_in_inferior (const char *);
 521
 522 extern struct value *value_allocate_space_in_inferior (int);
 523
 524 extern struct value *value_of_local (const char *name, int complain);
 525
 526 #endif /* !defined (VALUE_H) */