gdb/value.h

   1 /* Definitions for values of C expressions, for GDB.
   2
   3    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   4    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
   5    Free Software Foundation, Inc.
   6
   7    This file is part of GDB.
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 2 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program; if not, write to the Free Software
  21    Foundation, Inc., 59 Temple Place - Suite 330,
  22    Boston, MA 02111-1307, USA.  */
  23
  24 #if !defined (VALUE_H)
  25 #define VALUE_H 1
  26
  27 #include "doublest.h"
  28 #include "frame.h"              /* For struct frame_id.  */
  29
  30 struct block;
  31 struct expression;
  32 struct regcache;
  33 struct symbol;
  34 struct type;
  35 struct ui_file;
  36
  37 /* The structure which defines the type of a value.  It should never
  38    be possible for a program lval value to survive over a call to the
  39    inferior (i.e. to be put into the history list or an internal
  40    variable).  */
  41
  42 struct value
  43 {
  44   /* Type of value; either not an lval, or one of the various
  45      different possible kinds of lval.  */
  46   enum lval_type lval;
  47
  48   /* Is it modifiable?  Only relevant if lval != not_lval.  */
  49   int modifiable;
  50
  51   /* Location of value (if lval).  */
  52   union
  53   {
  54     /* If lval == lval_memory, this is the address in the inferior.
  55        If lval == lval_register, this is the byte offset into the
  56        registers structure.  */
  57     CORE_ADDR address;
  58
  59     /* Pointer to internal variable.  */
  60     struct internalvar *internalvar;
  61   } location;
  62
  63   /* Describes offset of a value within lval of a structure in bytes.
  64      If lval == lval_memory, this is an offset to the address.  If
  65      lval == lval_register, this is a further offset from
  66      location.address within the registers structure.  Note also the
  67      member embedded_offset below.  */
  68   int offset;
  69
  70   /* Only used for bitfields; number of bits contained in them.  */
  71   int bitsize;
  72
  73   /* Only used for bitfields; position of start of field.  For
  74      BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.  For
  75      BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  76   int bitpos;
  77
  78   /* Frame register value is relative to.  This will be described in
  79      the lval enum above as "lval_register".  */
  80   struct frame_id frame_id;
  81
  82   /* Type of the value.  */
  83   struct type *type;
  84
  85   /* If a value represents a C++ object, then the `type' field gives
  86      the object's compile-time type.  If the object actually belongs
  87      to some class derived from `type', perhaps with other base
  88      classes and additional members, then `type' is just a subobject
  89      of the real thing, and the full object is probably larger than
  90      `type' would suggest.
  91
  92      If `type' is a dynamic class (i.e. one with a vtable), then GDB
  93      can actually determine the object's run-time type by looking at
  94      the run-time type information in the vtable.  When this
  95      information is available, we may elect to read in the entire
  96      object, for several reasons:
  97
  98      - When printing the value, the user would probably rather see the
  99      full object, not just the limited portion apparent from the
 100      compile-time type.
 101
 102      - If `type' has virtual base classes, then even printing `type'
 103      alone may require reaching outside the `type' portion of the
 104      object to wherever the virtual base class has been stored.
 105
 106      When we store the entire object, `enclosing_type' is the run-time
 107      type -- the complete object -- and `embedded_offset' is the
 108      offset of `type' within that larger type, in bytes.  The
 109      value_contents() macro takes `embedded_offset' into account, so
 110      most GDB code continues to see the `type' portion of the value,
 111      just as the inferior would.
 112
 113      If `type' is a pointer to an object, then `enclosing_type' is a
 114      pointer to the object's run-time type, and `pointed_to_offset' is
 115      the offset in bytes from the full object to the pointed-to object
 116      -- that is, the value `embedded_offset' would have if we followed
 117      the pointer and fetched the complete object.  (I don't really see
 118      the point.  Why not just determine the run-time type when you
 119      indirect, and avoid the special case?  The contents don't matter
 120      until you indirect anyway.)
 121
 122      If we're not doing anything fancy, `enclosing_type' is equal to
 123      `type', and `embedded_offset' is zero, so everything works
 124      normally.  */
 125   struct type *enclosing_type;
 126   int embedded_offset;
 127   int pointed_to_offset;
 128
 129   /* Values are stored in a chain, so that they can be deleted easily
 130      over calls to the inferior.  Values assigned to internal
 131      variables or put into the value history are taken off this
 132      list.  */
 133   struct value *next;
 134
 135   /* Register number if the value is from a register.  */
 136   short regnum;
 137
 138   /* If zero, contents of this value are in the contents field.  If
 139      nonzero, contents are in inferior memory at address in the
 140      location.address field plus the offset field (and the lval field
 141      should be lval_memory).
 142
 143      WARNING: This field is used by the code which handles watchpoints
 144      (see breakpoint.c) to decide whether a particular value can be
 145      watched by hardware watchpoints.  If the lazy flag is set for
 146      some member of a value chain, it is assumed that this member of
 147      the chain doesn't need to be watched as part of watching the
 148      value itself.  This is how GDB avoids watching the entire struct
 149      or array when the user wants to watch a single struct member or
 150      array element.  If you ever change the way lazy flag is set and
 151      reset, be sure to consider this use as well!  */
 152   char lazy;
 153
 154   /* If nonzero, this is the value of a variable which does not
 155      actually exist in the program.  */
 156   char optimized_out;
 157
 158   /* Actual contents of the value.  For use of this value; setting it
 159      uses the stuff above.  Not valid if lazy is nonzero.  Target
 160      byte-order.  We force it to be aligned properly for any possible
 161      value.  Note that a value therefore extends beyond what is
 162      declared here.  */
 163   union
 164   {
 165     bfd_byte contents[1];
 166     DOUBLEST force_doublest_align;
 167     LONGEST force_longest_align;
 168     CORE_ADDR force_core_addr_align;
 169     void *force_pointer_align;
 170   } aligner;
 171   /* Do not add any new members here -- contents above will trash
 172      them.  */
 173 };
 174
 175 /* Values are stored in a chain, so that they can be deleted easily
 176    over calls to the inferior.  Values assigned to internal variables
 177    or put into the value history are taken off this list.  */
 178 struct value *value_next (struct value *);
 179
 180 extern struct type *value_type (struct value *);
 181 /* This is being used to change the type of an existing value, that
 182    code should instead be creating a new value with the changed type
 183    (but possibly shared content).  */
 184 extern void deprecated_set_value_type (struct value *value,
 185                                        struct type *type);
 186 extern int value_bitsize (struct value *);
 187 extern int value_bitpos (struct value *);
 188
 189 extern int value_offset (struct value *);
 190 extern void set_value_offset (struct value *, int offset);
 191
 192 /* The comment from "struct value" reads: ``Is it modifiable?  Only
 193    relevant if lval != not_lval.''.  Shouldn't the value instead be
 194    not_lval and be done with it?  */
 195 extern int deprecated_value_modifiable (struct value *value);
 196 extern void deprecated_set_value_modifiable (struct value *value,
 197                                              int modifiable);
 198
 199 extern struct type *value_enclosing_type (struct value *);
 200 extern int value_lazy (struct value *);
 201 extern void set_value_lazy (struct value *value, int val);
 202
 203 /* value_contents() and value_contents_raw() both return the address
 204    of the gdb buffer used to hold a copy of the contents of the lval.
 205    value_contents() is used when the contents of the buffer are needed
 206    -- it uses value_fetch_lazy() to load the buffer from the process
 207    being debugged if it hasn't already been loaded
 208    (value_contents_writeable() is used when a writeable but fetched
 209    buffer is required)..  value_contents_raw() is used when data is
 210    being stored into the buffer, or when it is certain that the
 211    contents of the buffer are valid.
 212
 213    Note: The contents pointer is adjusted by the offset required to
 214    get to the real subobject, if the value happens to represent
 215    something embedded in a larger run-time object.  */
 216
 217 extern bfd_byte *value_contents_raw (struct value *);
 218 extern const bfd_byte *value_contents (struct value *);
 219 extern bfd_byte *value_contents_writeable (struct value *);
 220
 221 /* The ALL variants of the above two macros do not adjust the returned
 222    pointer by the embedded_offset value.  */
 223
 224 extern bfd_byte *value_contents_all_raw (struct value *);
 225 extern const bfd_byte *value_contents_all (struct value *);
 226
 227 extern int value_fetch_lazy (struct value *val);
 228
 229 extern int value_optimized_out (struct value *value);
 230 extern void set_value_optimized_out (struct value *value, int val);
 231 extern int value_embedded_offset (struct value *value);
 232 extern void set_value_embedded_offset (struct value *value, int val);
 233 extern int value_pointed_to_offset (struct value *value);
 234 extern void set_value_pointed_to_offset (struct value *value, int val);
 235
 236 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 237    single value might have multiple LVALs), this hacked interface is
 238    limited to just the first PIECE.  Expect further change.  */
 239 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 240 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 241 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 242 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 243 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 244 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 245 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 246 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 247 extern short *deprecated_value_regnum_hack (struct value *);
 248 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 249
 250 /* Convert a REF to the object referenced.  */
 251
 252 extern struct value *coerce_ref (struct value *value);
 253
 254 /* If ARG is an array, convert it to a pointer.
 255    If ARG is an enum, convert it to an integer.
 256    If ARG is a function, convert it to a function pointer.
 257
 258    References are dereferenced.  */
 259
 260 extern struct value *coerce_array (struct value *value);
 261 extern struct value *coerce_number (struct value *value);
 262
 263 /* If ARG is an enum, convert it to an integer.  */
 264
 265 extern struct value *coerce_enum (struct value *value);
 266
 267 /* Internal variables (variables for convenience of use of debugger)
 268    are recorded as a chain of these structures.  */
 269
 270 struct internalvar
 271 {
 272   struct internalvar *next;
 273   char *name;
 274   struct value *value;
 275 };
 276
 277 /* Pointer to member function.  Depends on compiler implementation.  */
 278
 279 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 280 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 281 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 282 \f
 283
 284 #include "symtab.h"
 285 #include "gdbtypes.h"
 286 #include "expression.h"
 287
 288 struct frame_info;
 289 struct fn_field;
 290
 291 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 292
 293 extern LONGEST value_as_long (struct value *val);
 294 extern DOUBLEST value_as_double (struct value *val);
 295 extern CORE_ADDR value_as_address (struct value *val);
 296
 297 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 298 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 299                                int *invp);
 300 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 301 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 302                                      int fieldno);
 303
 304 extern struct value *value_from_longest (struct type *type, LONGEST num);
 305 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 306 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 307 extern struct value *value_from_string (char *string);
 308
 309 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 310 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 311
 312 extern struct value *value_from_register (struct type *type, int regnum,
 313                                           struct frame_info *frame);
 314
 315 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 316
 317 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 318
 319 extern int symbol_read_needs_frame (struct symbol *);
 320
 321 extern struct value *read_var_value (struct symbol *var,
 322                                      struct frame_info *frame);
 323
 324 extern struct value *locate_var_value (struct symbol *var,
 325                                        struct frame_info *frame);
 326
 327 extern struct value *allocate_value (struct type *type);
 328
 329 extern struct value *allocate_repeat_value (struct type *type, int count);
 330
 331 extern struct value *value_change_enclosing_type (struct value *val,
 332                                                   struct type *new_type);
 333
 334 extern struct value *value_mark (void);
 335
 336 extern void value_free_to_mark (struct value *mark);
 337
 338 extern struct value *value_string (char *ptr, int len);
 339 extern struct value *value_bitstring (char *ptr, int len);
 340
 341 extern struct value *value_array (int lowbound, int highbound,
 342                                   struct value **elemvec);
 343
 344 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 345
 346 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 347                                   enum exp_opcode op);
 348
 349 extern struct value *value_add (struct value *arg1, struct value *arg2);
 350
 351 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 352
 353 extern struct value *value_coerce_array (struct value *arg1);
 354
 355 extern struct value *value_coerce_function (struct value *arg1);
 356
 357 extern struct value *value_ind (struct value *arg1);
 358
 359 extern struct value *value_addr (struct value *arg1);
 360
 361 extern struct value *value_assign (struct value *toval,
 362                                    struct value *fromval);
 363
 364 extern struct value *value_neg (struct value *arg1);
 365
 366 extern struct value *value_complement (struct value *arg1);
 367
 368 extern struct value *value_struct_elt (struct value **argp,
 369                                        struct value **args,
 370                                        char *name, int *static_memfuncp,
 371                                        char *err);
 372
 373 extern struct value *value_aggregate_elt (struct type *curtype,
 374                                           char *name, enum noside noside);
 375
 376 extern struct value *value_static_field (struct type *type, int fieldno);
 377
 378 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 379                                                       int, int *,
 380                                                       struct type **, int *);
 381
 382 extern int find_overload_match (struct type **arg_types, int nargs,
 383                                 char *name, int method, int lax,
 384                                 struct value **objp, struct symbol *fsym,
 385                                 struct value **valp, struct symbol **symp,
 386                                 int *staticp);
 387
 388 extern struct value *value_field (struct value *arg1, int fieldno);
 389
 390 extern struct value *value_primitive_field (struct value *arg1, int offset,
 391                                             int fieldno,
 392                                             struct type *arg_type);
 393
 394
 395 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 396                                             int *);
 397
 398 extern struct value *value_full_object (struct value *, struct type *, int,
 399                                         int, int);
 400
 401 extern struct value *value_cast (struct type *type, struct value *arg2);
 402
 403 extern struct value *value_zero (struct type *type, enum lval_type lv);
 404
 405 extern struct value *value_repeat (struct value *arg1, int count);
 406
 407 extern struct value *value_subscript (struct value *array, struct value *idx);
 408
 409 extern struct value *register_value_being_returned (struct type *valtype,
 410                                                     struct regcache *retbuf);
 411
 412 extern struct value *value_in (struct value *element, struct value *set);
 413
 414 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 415                             int index);
 416
 417 extern int using_struct_return (struct type *value_type, int gcc_p);
 418
 419 extern struct value *evaluate_expression (struct expression *exp);
 420
 421 extern struct value *evaluate_type (struct expression *exp);
 422
 423 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 424                                                     int *, enum noside);
 425
 426 extern struct value *parse_and_eval (char *exp);
 427
 428 extern struct value *parse_to_comma_and_eval (char **expp);
 429
 430 extern struct type *parse_and_eval_type (char *p, int length);
 431
 432 extern CORE_ADDR parse_and_eval_address (char *exp);
 433
 434 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 435
 436 extern LONGEST parse_and_eval_long (char *exp);
 437
 438 extern struct value *access_value_history (int num);
 439
 440 extern struct value *value_of_internalvar (struct internalvar *var);
 441
 442 extern void set_internalvar (struct internalvar *var, struct value *val);
 443
 444 extern void set_internalvar_component (struct internalvar *var,
 445                                        int offset,
 446                                        int bitpos, int bitsize,
 447                                        struct value *newvalue);
 448
 449 extern struct internalvar *lookup_internalvar (char *name);
 450
 451 extern int value_equal (struct value *arg1, struct value *arg2);
 452
 453 extern int value_less (struct value *arg1, struct value *arg2);
 454
 455 extern int value_logical_not (struct value *arg1);
 456
 457 /* C++ */
 458
 459 extern struct value *value_of_this (int complain);
 460
 461 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 462                                     enum exp_opcode op,
 463                                     enum exp_opcode otherop,
 464                                     enum noside noside);
 465
 466 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 467                                    enum noside noside);
 468
 469 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 470                                      int j, struct type *type, int offset);
 471
 472 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 473                                  struct value *arg2);
 474
 475 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 476
 477 extern int destructor_name_p (const char *name, const struct type *type);
 478
 479 #define value_free(val) xfree (val)
 480
 481 extern void free_all_values (void);
 482
 483 extern void release_value (struct value *val);
 484
 485 extern int record_latest_value (struct value *val);
 486
 487 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 488                           int bitsize);
 489
 490 extern void type_print (struct type *type, char *varstring,
 491                         struct ui_file *stream, int show);
 492
 493 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 494                              struct value **valuep, int *errp);
 495
 496 extern void print_longest (struct ui_file *stream, int format,
 497                            int use_local, LONGEST val);
 498
 499 extern void print_floating (const bfd_byte *valaddr, struct type *type,
 500                             struct ui_file *stream);
 501
 502 extern int value_print (struct value *val, struct ui_file *stream, int format,
 503                         enum val_prettyprint pretty);
 504
 505 extern void value_print_array_elements (struct value *val,
 506                                         struct ui_file *stream, int format,
 507                                         enum val_prettyprint pretty);
 508
 509 extern struct value *value_release_to_mark (struct value *mark);
 510
 511 extern int val_print (struct type *type, const bfd_byte *valaddr,
 512                       int embedded_offset, CORE_ADDR address,
 513                       struct ui_file *stream, int format,
 514                       int deref_ref, int recurse,
 515                       enum val_prettyprint pretty);
 516
 517 extern int val_print_string (CORE_ADDR addr, int len, int width,
 518                              struct ui_file *stream);
 519
 520 extern void print_variable_value (struct symbol *var,
 521                                   struct frame_info *frame,
 522                                   struct ui_file *stream);
 523
 524 extern int check_field (struct value *, const char *);
 525
 526 extern void typedef_print (struct type *type, struct symbol *news,
 527                            struct ui_file *stream);
 528
 529 extern char *internalvar_name (struct internalvar *var);
 530
 531 extern void clear_value_history (void);
 532
 533 extern void clear_internalvars (void);
 534
 535 /* From values.c */
 536
 537 extern struct value *value_copy (struct value *);
 538
 539 /* From valops.c */
 540
 541 extern struct value *varying_to_slice (struct value *);
 542
 543 extern struct value *value_slice (struct value *, int, int);
 544
 545 extern struct value *value_literal_complex (struct value *, struct value *,
 546                                             struct type *);
 547
 548 extern void find_rt_vbase_offset (struct type *, struct type *,
 549                                   const bfd_byte *, int, int *, int *);
 550
 551 extern struct value *find_function_in_inferior (const char *);
 552
 553 extern struct value *value_allocate_space_in_inferior (int);
 554
 555 extern struct value *value_of_local (const char *name, int complain);
 556
 557 #endif /* !defined (VALUE_H) */