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   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 *value_from_register (struct type *type, int regnum,
 283                                           struct frame_info *frame);
 284
 285 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 286
 287 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 288
 289 extern int symbol_read_needs_frame (struct symbol *);
 290
 291 extern struct value *read_var_value (struct symbol *var,
 292                                      struct frame_info *frame);
 293
 294 extern struct value *locate_var_value (struct symbol *var,
 295                                        struct frame_info *frame);
 296
 297 extern struct value *allocate_value (struct type *type);
 298
 299 extern struct value *allocate_repeat_value (struct type *type, int count);
 300
 301 extern struct value *value_mark (void);
 302
 303 extern void value_free_to_mark (struct value *mark);
 304
 305 extern struct value *value_string (char *ptr, int len);
 306 extern struct value *value_bitstring (char *ptr, int len);
 307
 308 extern struct value *value_array (int lowbound, int highbound,
 309                                   struct value **elemvec);
 310
 311 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 312
 313 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 314                                   enum exp_opcode op);
 315
 316 extern struct value *value_add (struct value *arg1, struct value *arg2);
 317
 318 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 319
 320 extern struct value *value_coerce_array (struct value *arg1);
 321
 322 extern struct value *value_coerce_function (struct value *arg1);
 323
 324 extern struct value *value_ind (struct value *arg1);
 325
 326 extern struct value *value_addr (struct value *arg1);
 327
 328 extern struct value *value_assign (struct value *toval,
 329                                    struct value *fromval);
 330
 331 extern struct value *value_pos (struct value *arg1);
 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 gdb_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 (gdb_byte *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 gdb_byte *baseclass_addr (struct type *type, int index,
 463                                  gdb_byte *valaddr,
 464                                  struct value **valuep, int *errp);
 465
 466 extern void print_longest (struct ui_file *stream, int format,
 467                            int use_local, LONGEST val);
 468
 469 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 470                             struct ui_file *stream);
 471
 472 extern int value_print (struct value *val, struct ui_file *stream, int format,
 473                         enum val_prettyprint pretty);
 474
 475 extern void value_print_array_elements (struct value *val,
 476                                         struct ui_file *stream, int format,
 477                                         enum val_prettyprint pretty);
 478
 479 extern struct value *value_release_to_mark (struct value *mark);
 480
 481 extern int val_print (struct type *type, const gdb_byte *valaddr,
 482                       int embedded_offset, CORE_ADDR address,
 483                       struct ui_file *stream, int format,
 484                       int deref_ref, int recurse,
 485                       enum val_prettyprint pretty);
 486
 487 extern int common_val_print (struct value *val,
 488                              struct ui_file *stream, int format,
 489                              int deref_ref, int recurse,
 490                              enum val_prettyprint pretty);
 491
 492 extern int val_print_string (CORE_ADDR addr, int len, int width,
 493                              struct ui_file *stream);
 494
 495 extern void print_variable_value (struct symbol *var,
 496                                   struct frame_info *frame,
 497                                   struct ui_file *stream);
 498
 499 extern int check_field (struct value *, const char *);
 500
 501 extern void typedef_print (struct type *type, struct symbol *news,
 502                            struct ui_file *stream);
 503
 504 extern char *internalvar_name (struct internalvar *var);
 505
 506 extern void preserve_values (struct objfile *);
 507
 508 /* From values.c */
 509
 510 extern struct value *value_copy (struct value *);
 511
 512 /* From valops.c */
 513
 514 extern struct value *varying_to_slice (struct value *);
 515
 516 extern struct value *value_slice (struct value *, int, int);
 517
 518 extern struct value *value_literal_complex (struct value *, struct value *,
 519                                             struct type *);
 520
 521 extern void find_rt_vbase_offset (struct type *, struct type *,
 522                                   const gdb_byte *, int, int *, int *);
 523
 524 extern struct value *find_function_in_inferior (const char *);
 525
 526 extern struct value *value_allocate_space_in_inferior (int);
 527
 528 extern struct value *value_of_local (const char *name, int complain);
 529
 530 #endif /* !defined (VALUE_H) */