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