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    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., 51 Franklin Street, Fifth Floor,
  22    Boston, MA 02110-1301, 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 gdb_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 gdb_byte *value_contents (struct value *);
 180 extern gdb_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 gdb_byte *value_contents_all_raw (struct value *);
 186 extern const gdb_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   int endian;
 249 };
 250
 251 \f
 252
 253 #include "symtab.h"
 254 #include "gdbtypes.h"
 255 #include "expression.h"
 256
 257 struct frame_info;
 258 struct fn_field;
 259
 260 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 261
 262 extern LONGEST value_as_long (struct value *val);
 263 extern DOUBLEST value_as_double (struct value *val);
 264 extern CORE_ADDR value_as_address (struct value *val);
 265
 266 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
 267 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
 268                                int *invp);
 269 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
 270 extern LONGEST unpack_field_as_long (struct type *type,
 271                                      const gdb_byte *valaddr,
 272                                      int fieldno);
 273
 274 extern struct value *value_from_longest (struct type *type, LONGEST num);
 275 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 276 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 277 extern struct value *value_from_string (char *string);
 278
 279 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 280 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 281
 282 extern struct value *default_value_from_register (struct type *type,
 283                                                   int regnum,
 284                                                   struct frame_info *frame);
 285
 286 extern struct value *value_from_register (struct type *type, int regnum,
 287                                           struct frame_info *frame);
 288
 289 extern CORE_ADDR address_from_register (struct type *type, int regnum,
 290                                         struct frame_info *frame);
 291
 292 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 293
 294 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 295
 296 extern int symbol_read_needs_frame (struct symbol *);
 297
 298 extern struct value *read_var_value (struct symbol *var,
 299                                      struct frame_info *frame);
 300
 301 extern struct value *locate_var_value (struct symbol *var,
 302                                        struct frame_info *frame);
 303
 304 extern struct value *allocate_value (struct type *type);
 305
 306 extern struct value *allocate_repeat_value (struct type *type, int count);
 307
 308 extern struct value *value_mark (void);
 309
 310 extern void value_free_to_mark (struct value *mark);
 311
 312 extern struct value *value_string (char *ptr, int len);
 313 extern struct value *value_bitstring (char *ptr, int len);
 314
 315 extern struct value *value_array (int lowbound, int highbound,
 316                                   struct value **elemvec);
 317
 318 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 319
 320 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 321                                   enum exp_opcode op);
 322
 323 extern struct value *value_add (struct value *arg1, struct value *arg2);
 324
 325 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 326
 327 extern struct value *value_coerce_array (struct value *arg1);
 328
 329 extern struct value *value_coerce_function (struct value *arg1);
 330
 331 extern struct value *value_ind (struct value *arg1);
 332
 333 extern struct value *value_addr (struct value *arg1);
 334
 335 extern struct value *value_ref (struct value *arg1);
 336
 337 extern struct value *value_assign (struct value *toval,
 338                                    struct value *fromval);
 339
 340 extern struct value *value_pos (struct value *arg1);
 341
 342 extern struct value *value_neg (struct value *arg1);
 343
 344 extern struct value *value_complement (struct value *arg1);
 345
 346 extern struct value *value_struct_elt (struct value **argp,
 347                                        struct value **args,
 348                                        char *name, int *static_memfuncp,
 349                                        char *err);
 350
 351 extern struct value *value_aggregate_elt (struct type *curtype,
 352                                           char *name,
 353                                           int want_address,
 354                                           enum noside noside);
 355
 356 extern struct value *value_static_field (struct type *type, int fieldno);
 357
 358 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 359                                                       int, int *,
 360                                                       struct type **, int *);
 361
 362 extern int find_overload_match (struct type **arg_types, int nargs,
 363                                 char *name, int method, int lax,
 364                                 struct value **objp, struct symbol *fsym,
 365                                 struct value **valp, struct symbol **symp,
 366                                 int *staticp);
 367
 368 extern struct value *value_field (struct value *arg1, int fieldno);
 369
 370 extern struct value *value_primitive_field (struct value *arg1, int offset,
 371                                             int fieldno,
 372                                             struct type *arg_type);
 373
 374
 375 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 376                                             int *);
 377
 378 extern struct value *value_full_object (struct value *, struct type *, int,
 379                                         int, int);
 380
 381 extern struct value *value_cast_pointers (struct type *, struct value *);
 382
 383 extern struct value *value_cast (struct type *type, struct value *arg2);
 384
 385 extern struct value *value_zero (struct type *type, enum lval_type lv);
 386
 387 extern struct value *value_repeat (struct value *arg1, int count);
 388
 389 extern struct value *value_subscript (struct value *array, struct value *idx);
 390
 391 extern struct value *register_value_being_returned (struct type *valtype,
 392                                                     struct regcache *retbuf);
 393
 394 extern struct value *value_in (struct value *element, struct value *set);
 395
 396 extern int value_bit_index (struct type *type, const gdb_byte *addr,
 397                             int index);
 398
 399 extern int using_struct_return (struct type *value_type, int gcc_p);
 400
 401 extern struct value *evaluate_expression (struct expression *exp);
 402
 403 extern struct value *evaluate_type (struct expression *exp);
 404
 405 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 406                                                     int *, enum noside);
 407
 408 extern struct value *parse_and_eval (char *exp);
 409
 410 extern struct value *parse_to_comma_and_eval (char **expp);
 411
 412 extern struct type *parse_and_eval_type (char *p, int length);
 413
 414 extern CORE_ADDR parse_and_eval_address (char *exp);
 415
 416 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 417
 418 extern LONGEST parse_and_eval_long (char *exp);
 419
 420 extern struct value *access_value_history (int num);
 421
 422 extern struct value *value_of_internalvar (struct internalvar *var);
 423
 424 extern void set_internalvar (struct internalvar *var, struct value *val);
 425
 426 extern void set_internalvar_component (struct internalvar *var,
 427                                        int offset,
 428                                        int bitpos, int bitsize,
 429                                        struct value *newvalue);
 430
 431 extern struct internalvar *lookup_internalvar (char *name);
 432
 433 extern int value_equal (struct value *arg1, struct value *arg2);
 434
 435 extern int value_less (struct value *arg1, struct value *arg2);
 436
 437 extern int value_logical_not (struct value *arg1);
 438
 439 /* C++ */
 440
 441 extern struct value *value_of_this (int complain);
 442
 443 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 444                                     enum exp_opcode op,
 445                                     enum exp_opcode otherop,
 446                                     enum noside noside);
 447
 448 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 449                                    enum noside noside);
 450
 451 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 452                                      int j, struct type *type, int offset);
 453
 454 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 455                                  struct value *arg2);
 456
 457 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 458
 459 extern int destructor_name_p (const char *name, const struct type *type);
 460
 461 #define value_free(val) xfree (val)
 462
 463 extern void free_all_values (void);
 464
 465 extern void release_value (struct value *val);
 466
 467 extern int record_latest_value (struct value *val);
 468
 469 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
 470                           int bitsize);
 471
 472 extern void type_print (struct type *type, char *varstring,
 473                         struct ui_file *stream, int show);
 474
 475 extern gdb_byte *baseclass_addr (struct type *type, int index,
 476                                  gdb_byte *valaddr,
 477                                  struct value **valuep, int *errp);
 478
 479 extern void print_longest (struct ui_file *stream, int format,
 480                            int use_local, LONGEST val);
 481
 482 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 483                             struct ui_file *stream);
 484
 485 extern int value_print (struct value *val, struct ui_file *stream, int format,
 486                         enum val_prettyprint pretty);
 487
 488 extern void value_print_array_elements (struct value *val,
 489                                         struct ui_file *stream, int format,
 490                                         enum val_prettyprint pretty);
 491
 492 extern struct value *value_release_to_mark (struct value *mark);
 493
 494 extern int val_print (struct type *type, const gdb_byte *valaddr,
 495                       int embedded_offset, CORE_ADDR address,
 496                       struct ui_file *stream, int format,
 497                       int deref_ref, int recurse,
 498                       enum val_prettyprint pretty);
 499
 500 extern int common_val_print (struct value *val,
 501                              struct ui_file *stream, int format,
 502                              int deref_ref, int recurse,
 503                              enum val_prettyprint pretty);
 504
 505 extern int val_print_string (CORE_ADDR addr, int len, int width,
 506                              struct ui_file *stream);
 507
 508 extern void print_variable_value (struct symbol *var,
 509                                   struct frame_info *frame,
 510                                   struct ui_file *stream);
 511
 512 extern int check_field (struct value *, const char *);
 513
 514 extern void typedef_print (struct type *type, struct symbol *news,
 515                            struct ui_file *stream);
 516
 517 extern char *internalvar_name (struct internalvar *var);
 518
 519 extern void preserve_values (struct objfile *);
 520
 521 /* From values.c */
 522
 523 extern struct value *value_copy (struct value *);
 524
 525 /* From valops.c */
 526
 527 extern struct value *varying_to_slice (struct value *);
 528
 529 extern struct value *value_slice (struct value *, int, int);
 530
 531 extern struct value *value_literal_complex (struct value *, struct value *,
 532                                             struct type *);
 533
 534 extern void find_rt_vbase_offset (struct type *, struct type *,
 535                                   const gdb_byte *, int, int *, int *);
 536
 537 extern struct value *find_function_in_inferior (const char *);
 538
 539 extern struct value *value_allocate_space_in_inferior (int);
 540
 541 extern struct value *value_of_local (const char *name, int complain);
 542
 543 #endif /* !defined (VALUE_H) */