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 /* Set or return field indicating whether a variable is initialized or
 197    not, based on debugging information supplied by the compiler.
 198    1 = initialized; 0 = uninitialized.  */
 199 extern int value_initialized (struct value *);
 200 extern void set_value_initialized (struct value *, int);
 201
 202 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 203    single value might have multiple LVALs), this hacked interface is
 204    limited to just the first PIECE.  Expect further change.  */
 205 /* Type of value; either not an lval, or one of the various different
 206    possible kinds of lval.  */
 207 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 208 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 209
 210 /* If lval == lval_memory, this is the address in the inferior.  If
 211    lval == lval_register, this is the byte offset into the registers
 212    structure.  */
 213 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 214 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 215
 216 /* Pointer to internal variable.  */
 217 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 218 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 219
 220 /* Frame register value is relative to.  This will be described in the
 221    lval enum above as "lval_register".  */
 222 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 223 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 224
 225 /* Register number if the value is from a register.  */
 226 extern short *deprecated_value_regnum_hack (struct value *);
 227 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 228
 229 /* Convert a REF to the object referenced.  */
 230
 231 extern struct value *coerce_ref (struct value *value);
 232
 233 /* If ARG is an array, convert it to a pointer.
 234    If ARG is an enum, convert it to an integer.
 235    If ARG is a function, convert it to a function pointer.
 236
 237    References are dereferenced.  */
 238
 239 extern struct value *coerce_array (struct value *value);
 240 extern struct value *coerce_number (struct value *value);
 241
 242 /* If ARG is an enum, convert it to an integer.  */
 243
 244 extern struct value *coerce_enum (struct value *value);
 245
 246 /* Internal variables (variables for convenience of use of debugger)
 247    are recorded as a chain of these structures.  */
 248
 249 struct internalvar
 250 {
 251   struct internalvar *next;
 252   char *name;
 253   struct value *value;
 254   int endian;
 255 };
 256
 257 \f
 258
 259 #include "symtab.h"
 260 #include "gdbtypes.h"
 261 #include "expression.h"
 262
 263 struct frame_info;
 264 struct fn_field;
 265
 266 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 267
 268 extern LONGEST value_as_long (struct value *val);
 269 extern DOUBLEST value_as_double (struct value *val);
 270 extern CORE_ADDR value_as_address (struct value *val);
 271
 272 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr);
 273 extern DOUBLEST unpack_double (struct type *type, const gdb_byte *valaddr,
 274                                int *invp);
 275 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr);
 276 extern LONGEST unpack_field_as_long (struct type *type,
 277                                      const gdb_byte *valaddr,
 278                                      int fieldno);
 279
 280 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num);
 281
 282 extern struct value *value_from_longest (struct type *type, LONGEST num);
 283 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 284 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 285 extern struct value *value_from_string (char *string);
 286
 287 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 288 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 289
 290 extern struct value *default_value_from_register (struct type *type,
 291                                                   int regnum,
 292                                                   struct frame_info *frame);
 293
 294 extern struct value *value_from_register (struct type *type, int regnum,
 295                                           struct frame_info *frame);
 296
 297 extern CORE_ADDR address_from_register (struct type *type, int regnum,
 298                                         struct frame_info *frame);
 299
 300 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 301
 302 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 303
 304 extern int symbol_read_needs_frame (struct symbol *);
 305
 306 extern struct value *read_var_value (struct symbol *var,
 307                                      struct frame_info *frame);
 308
 309 extern struct value *locate_var_value (struct symbol *var,
 310                                        struct frame_info *frame);
 311
 312 extern struct value *allocate_value (struct type *type);
 313
 314 extern struct value *allocate_repeat_value (struct type *type, int count);
 315
 316 extern struct value *value_mark (void);
 317
 318 extern void value_free_to_mark (struct value *mark);
 319
 320 extern struct value *value_string (char *ptr, int len);
 321 extern struct value *value_bitstring (char *ptr, int len);
 322
 323 extern struct value *value_array (int lowbound, int highbound,
 324                                   struct value **elemvec);
 325
 326 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 327
 328 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 329                                   enum exp_opcode op);
 330
 331 extern struct value *value_add (struct value *arg1, struct value *arg2);
 332
 333 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 334
 335 extern struct value *value_coerce_array (struct value *arg1);
 336
 337 extern struct value *value_coerce_function (struct value *arg1);
 338
 339 extern struct value *value_ind (struct value *arg1);
 340
 341 extern struct value *value_addr (struct value *arg1);
 342
 343 extern struct value *value_ref (struct value *arg1);
 344
 345 extern struct value *value_assign (struct value *toval,
 346                                    struct value *fromval);
 347
 348 extern struct value *value_pos (struct value *arg1);
 349
 350 extern struct value *value_neg (struct value *arg1);
 351
 352 extern struct value *value_complement (struct value *arg1);
 353
 354 extern struct value *value_struct_elt (struct value **argp,
 355                                        struct value **args,
 356                                        char *name, int *static_memfuncp,
 357                                        char *err);
 358
 359 extern struct value *value_aggregate_elt (struct type *curtype,
 360                                           char *name,
 361                                           int want_address,
 362                                           enum noside noside);
 363
 364 extern struct value *value_static_field (struct type *type, int fieldno);
 365
 366 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 367                                                       int, int *,
 368                                                       struct type **, int *);
 369
 370 extern int find_overload_match (struct type **arg_types, int nargs,
 371                                 char *name, int method, int lax,
 372                                 struct value **objp, struct symbol *fsym,
 373                                 struct value **valp, struct symbol **symp,
 374                                 int *staticp);
 375
 376 extern struct value *value_field (struct value *arg1, int fieldno);
 377
 378 extern struct value *value_primitive_field (struct value *arg1, int offset,
 379                                             int fieldno,
 380                                             struct type *arg_type);
 381
 382
 383 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 384                                             int *);
 385
 386 extern struct value *value_full_object (struct value *, struct type *, int,
 387                                         int, int);
 388
 389 extern struct value *value_cast_pointers (struct type *, struct value *);
 390
 391 extern struct value *value_cast (struct type *type, struct value *arg2);
 392
 393 extern struct value *value_zero (struct type *type, enum lval_type lv);
 394
 395 extern struct value *value_repeat (struct value *arg1, int count);
 396
 397 extern struct value *value_subscript (struct value *array, struct value *idx);
 398
 399 extern struct value *register_value_being_returned (struct type *valtype,
 400                                                     struct regcache *retbuf);
 401
 402 extern struct value *value_in (struct value *element, struct value *set);
 403
 404 extern int value_bit_index (struct type *type, const gdb_byte *addr,
 405                             int index);
 406
 407 extern int using_struct_return (struct type *value_type, int gcc_p);
 408
 409 extern struct value *evaluate_expression (struct expression *exp);
 410
 411 extern struct value *evaluate_type (struct expression *exp);
 412
 413 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 414                                                     int *, enum noside);
 415
 416 extern struct value *parse_and_eval (char *exp);
 417
 418 extern struct value *parse_to_comma_and_eval (char **expp);
 419
 420 extern struct type *parse_and_eval_type (char *p, int length);
 421
 422 extern CORE_ADDR parse_and_eval_address (char *exp);
 423
 424 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 425
 426 extern LONGEST parse_and_eval_long (char *exp);
 427
 428 extern struct value *access_value_history (int num);
 429
 430 extern struct value *value_of_internalvar (struct internalvar *var);
 431
 432 extern void set_internalvar (struct internalvar *var, struct value *val);
 433
 434 extern void set_internalvar_component (struct internalvar *var,
 435                                        int offset,
 436                                        int bitpos, int bitsize,
 437                                        struct value *newvalue);
 438
 439 extern struct internalvar *lookup_internalvar (char *name);
 440
 441 extern int value_equal (struct value *arg1, struct value *arg2);
 442
 443 extern int value_less (struct value *arg1, struct value *arg2);
 444
 445 extern int value_logical_not (struct value *arg1);
 446
 447 /* C++ */
 448
 449 extern struct value *value_of_this (int complain);
 450
 451 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 452                                     enum exp_opcode op,
 453                                     enum exp_opcode otherop,
 454                                     enum noside noside);
 455
 456 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 457                                    enum noside noside);
 458
 459 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 460                                      int j, struct type *type, int offset);
 461
 462 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 463                                  struct value *arg2);
 464
 465 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 466
 467 extern int destructor_name_p (const char *name, const struct type *type);
 468
 469 #define value_free(val) xfree (val)
 470
 471 extern void free_all_values (void);
 472
 473 extern void release_value (struct value *val);
 474
 475 extern int record_latest_value (struct value *val);
 476
 477 extern void modify_field (gdb_byte *addr, LONGEST fieldval, int bitpos,
 478                           int bitsize);
 479
 480 extern void type_print (struct type *type, char *varstring,
 481                         struct ui_file *stream, int show);
 482
 483 extern gdb_byte *baseclass_addr (struct type *type, int index,
 484                                  gdb_byte *valaddr,
 485                                  struct value **valuep, int *errp);
 486
 487 extern void print_longest (struct ui_file *stream, int format,
 488                            int use_local, LONGEST val);
 489
 490 extern void print_floating (const gdb_byte *valaddr, struct type *type,
 491                             struct ui_file *stream);
 492
 493 extern int value_print (struct value *val, struct ui_file *stream, int format,
 494                         enum val_prettyprint pretty);
 495
 496 extern void value_print_array_elements (struct value *val,
 497                                         struct ui_file *stream, int format,
 498                                         enum val_prettyprint pretty);
 499
 500 extern struct value *value_release_to_mark (struct value *mark);
 501
 502 extern int val_print (struct type *type, const gdb_byte *valaddr,
 503                       int embedded_offset, CORE_ADDR address,
 504                       struct ui_file *stream, int format,
 505                       int deref_ref, int recurse,
 506                       enum val_prettyprint pretty);
 507
 508 extern int common_val_print (struct value *val,
 509                              struct ui_file *stream, int format,
 510                              int deref_ref, int recurse,
 511                              enum val_prettyprint pretty);
 512
 513 extern int val_print_string (CORE_ADDR addr, int len, int width,
 514                              struct ui_file *stream);
 515
 516 extern void print_variable_value (struct symbol *var,
 517                                   struct frame_info *frame,
 518                                   struct ui_file *stream);
 519
 520 extern int check_field (struct value *, const char *);
 521
 522 extern void typedef_print (struct type *type, struct symbol *news,
 523                            struct ui_file *stream);
 524
 525 extern char *internalvar_name (struct internalvar *var);
 526
 527 extern void preserve_values (struct objfile *);
 528
 529 /* From values.c */
 530
 531 extern struct value *value_copy (struct value *);
 532
 533 /* From valops.c */
 534
 535 extern struct value *varying_to_slice (struct value *);
 536
 537 extern struct value *value_slice (struct value *, int, int);
 538
 539 extern struct value *value_literal_complex (struct value *, struct value *,
 540                                             struct type *);
 541
 542 extern void find_rt_vbase_offset (struct type *, struct type *,
 543                                   const gdb_byte *, int, int *, int *);
 544
 545 extern struct value *find_function_in_inferior (const char *);
 546
 547 extern struct value *value_allocate_space_in_inferior (int);
 548
 549 extern struct value *value_of_local (const char *name, int complain);
 550
 551 #endif /* !defined (VALUE_H) */