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 #ifdef VALUE_C
  84   struct type *type;
  85 #else
  86   struct type *xtype;
  87 #endif
  88
  89   /* If a value represents a C++ object, then the `type' field gives
  90      the object's compile-time type.  If the object actually belongs
  91      to some class derived from `type', perhaps with other base
  92      classes and additional members, then `type' is just a subobject
  93      of the real thing, and the full object is probably larger than
  94      `type' would suggest.
  95
  96      If `type' is a dynamic class (i.e. one with a vtable), then GDB
  97      can actually determine the object's run-time type by looking at
  98      the run-time type information in the vtable.  When this
  99      information is available, we may elect to read in the entire
 100      object, for several reasons:
 101
 102      - When printing the value, the user would probably rather see the
 103      full object, not just the limited portion apparent from the
 104      compile-time type.
 105
 106      - If `type' has virtual base classes, then even printing `type'
 107      alone may require reaching outside the `type' portion of the
 108      object to wherever the virtual base class has been stored.
 109
 110      When we store the entire object, `enclosing_type' is the run-time
 111      type -- the complete object -- and `embedded_offset' is the
 112      offset of `type' within that larger type, in bytes.  The
 113      value_contents() macro takes `embedded_offset' into account, so
 114      most GDB code continues to see the `type' portion of the value,
 115      just as the inferior would.
 116
 117      If `type' is a pointer to an object, then `enclosing_type' is a
 118      pointer to the object's run-time type, and `pointed_to_offset' is
 119      the offset in bytes from the full object to the pointed-to object
 120      -- that is, the value `embedded_offset' would have if we followed
 121      the pointer and fetched the complete object.  (I don't really see
 122      the point.  Why not just determine the run-time type when you
 123      indirect, and avoid the special case?  The contents don't matter
 124      until you indirect anyway.)
 125
 126      If we're not doing anything fancy, `enclosing_type' is equal to
 127      `type', and `embedded_offset' is zero, so everything works
 128      normally.  */
 129   struct type *enclosing_type;
 130   int embedded_offset;
 131   int pointed_to_offset;
 132
 133   /* Values are stored in a chain, so that they can be deleted easily
 134      over calls to the inferior.  Values assigned to internal
 135      variables or put into the value history are taken off this
 136      list.  */
 137   struct value *next;
 138
 139   /* Register number if the value is from a register.  */
 140   short regnum;
 141
 142   /* If zero, contents of this value are in the contents field.  If
 143      nonzero, contents are in inferior memory at address in the
 144      location.address field plus the offset field (and the lval field
 145      should be lval_memory).
 146
 147      WARNING: This field is used by the code which handles watchpoints
 148      (see breakpoint.c) to decide whether a particular value can be
 149      watched by hardware watchpoints.  If the lazy flag is set for
 150      some member of a value chain, it is assumed that this member of
 151      the chain doesn't need to be watched as part of watching the
 152      value itself.  This is how GDB avoids watching the entire struct
 153      or array when the user wants to watch a single struct member or
 154      array element.  If you ever change the way lazy flag is set and
 155      reset, be sure to consider this use as well!  */
 156   char lazy;
 157
 158   /* If nonzero, this is the value of a variable which does not
 159      actually exist in the program.  */
 160   char optimized_out;
 161
 162   /* Actual contents of the value.  For use of this value; setting it
 163      uses the stuff above.  Not valid if lazy is nonzero.  Target
 164      byte-order.  We force it to be aligned properly for any possible
 165      value.  Note that a value therefore extends beyond what is
 166      declared here.  */
 167   union
 168   {
 169     bfd_byte contents[1];
 170     DOUBLEST force_doublest_align;
 171     LONGEST force_longest_align;
 172     CORE_ADDR force_core_addr_align;
 173     void *force_pointer_align;
 174   } aligner;
 175   /* Do not add any new members here -- contents above will trash
 176      them.  */
 177 };
 178
 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 extern int value_offset (struct value *);
 189
 190 extern struct type *value_enclosing_type (struct value *);
 191 extern int value_lazy (struct value *);
 192 extern void set_value_lazy (struct value *value, int val);
 193
 194 /* value_contents() and value_contents_raw() both return the address
 195    of the gdb buffer used to hold a copy of the contents of the lval.
 196    value_contents() is used when the contents of the buffer are needed
 197    -- it uses value_fetch_lazy() to load the buffer from the process
 198    being debugged if it hasn't already been loaded
 199    (value_contents_writeable() is used when a writeable but fetched
 200    buffer is required)..  value_contents_raw() is used when data is
 201    being stored into the buffer, or when it is certain that the
 202    contents of the buffer are valid.
 203
 204    Note: The contents pointer is adjusted by the offset required to
 205    get to the real subobject, if the value happens to represent
 206    something embedded in a larger run-time object.  */
 207
 208 extern bfd_byte *value_contents_raw (struct value *);
 209 extern const bfd_byte *value_contents (struct value *);
 210 extern bfd_byte *value_contents_writeable (struct value *);
 211
 212 /* The ALL variants of the above two macros do not adjust the returned
 213    pointer by the embedded_offset value.  */
 214
 215 extern bfd_byte *value_contents_all_raw (struct value *);
 216 extern const bfd_byte *value_contents_all (struct value *);
 217
 218 extern int value_fetch_lazy (struct value *val);
 219
 220 extern int value_optimized_out (struct value *value);
 221 extern void set_value_optimized_out (struct value *value, int val);
 222 extern int value_embedded_offset (struct value *value);
 223 extern void set_value_embedded_offset (struct value *value, int val);
 224 extern int value_pointed_to_offset (struct value *value);
 225 extern void set_value_pointed_to_offset (struct value *value, int val);
 226
 227 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a
 228    single value might have multiple LVALs), this hacked interface is
 229    limited to just the first PIECE.  Expect further change.  */
 230 extern enum lval_type *deprecated_value_lval_hack (struct value *);
 231 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val))
 232 extern CORE_ADDR *deprecated_value_address_hack (struct value *);
 233 #define VALUE_ADDRESS(val) (*deprecated_value_address_hack (val))
 234 extern struct internalvar **deprecated_value_internalvar_hack (struct value *);
 235 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val))
 236 extern struct frame_id *deprecated_value_frame_id_hack (struct value *);
 237 #define VALUE_FRAME_ID(val) (*deprecated_value_frame_id_hack (val))
 238 extern short *deprecated_value_regnum_hack (struct value *);
 239 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val))
 240
 241 /* Convert a REF to the object referenced.  */
 242
 243 extern struct value *coerce_ref (struct value *value);
 244
 245 /* If ARG is an array, convert it to a pointer.
 246    If ARG is an enum, convert it to an integer.
 247    If ARG is a function, convert it to a function pointer.
 248
 249    References are dereferenced.  */
 250
 251 extern struct value *coerce_array (struct value *value);
 252 extern struct value *coerce_number (struct value *value);
 253
 254 /* If ARG is an enum, convert it to an integer.  */
 255
 256 extern struct value *coerce_enum (struct value *value);
 257
 258 /* Internal variables (variables for convenience of use of debugger)
 259    are recorded as a chain of these structures.  */
 260
 261 struct internalvar
 262 {
 263   struct internalvar *next;
 264   char *name;
 265   struct value *value;
 266 };
 267
 268 /* Pointer to member function.  Depends on compiler implementation.  */
 269
 270 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 271 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 272 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 273 \f
 274
 275 #include "symtab.h"
 276 #include "gdbtypes.h"
 277 #include "expression.h"
 278
 279 struct frame_info;
 280 struct fn_field;
 281
 282 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 283
 284 extern LONGEST value_as_long (struct value *val);
 285 extern DOUBLEST value_as_double (struct value *val);
 286 extern CORE_ADDR value_as_address (struct value *val);
 287
 288 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 289 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 290                                int *invp);
 291 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 292 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 293                                      int fieldno);
 294
 295 extern struct value *value_from_longest (struct type *type, LONGEST num);
 296 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 297 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 298 extern struct value *value_from_string (char *string);
 299
 300 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 301 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 302
 303 extern struct value *value_from_register (struct type *type, int regnum,
 304                                           struct frame_info *frame);
 305
 306 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 307
 308 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 309
 310 extern int symbol_read_needs_frame (struct symbol *);
 311
 312 extern struct value *read_var_value (struct symbol *var,
 313                                      struct frame_info *frame);
 314
 315 extern struct value *locate_var_value (struct symbol *var,
 316                                        struct frame_info *frame);
 317
 318 extern struct value *allocate_value (struct type *type);
 319
 320 extern struct value *allocate_repeat_value (struct type *type, int count);
 321
 322 extern struct value *value_change_enclosing_type (struct value *val,
 323                                                   struct type *new_type);
 324
 325 extern struct value *value_mark (void);
 326
 327 extern void value_free_to_mark (struct value *mark);
 328
 329 extern struct value *value_string (char *ptr, int len);
 330 extern struct value *value_bitstring (char *ptr, int len);
 331
 332 extern struct value *value_array (int lowbound, int highbound,
 333                                   struct value **elemvec);
 334
 335 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 336
 337 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 338                                   enum exp_opcode op);
 339
 340 extern struct value *value_add (struct value *arg1, struct value *arg2);
 341
 342 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 343
 344 extern struct value *value_coerce_array (struct value *arg1);
 345
 346 extern struct value *value_coerce_function (struct value *arg1);
 347
 348 extern struct value *value_ind (struct value *arg1);
 349
 350 extern struct value *value_addr (struct value *arg1);
 351
 352 extern struct value *value_assign (struct value *toval,
 353                                    struct value *fromval);
 354
 355 extern struct value *value_neg (struct value *arg1);
 356
 357 extern struct value *value_complement (struct value *arg1);
 358
 359 extern struct value *value_struct_elt (struct value **argp,
 360                                        struct value **args,
 361                                        char *name, int *static_memfuncp,
 362                                        char *err);
 363
 364 extern struct value *value_aggregate_elt (struct type *curtype,
 365                                           char *name, enum noside noside);
 366
 367 extern struct value *value_static_field (struct type *type, int fieldno);
 368
 369 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 370                                                       int, int *,
 371                                                       struct type **, int *);
 372
 373 extern int find_overload_match (struct type **arg_types, int nargs,
 374                                 char *name, int method, int lax,
 375                                 struct value **objp, struct symbol *fsym,
 376                                 struct value **valp, struct symbol **symp,
 377                                 int *staticp);
 378
 379 extern struct value *value_field (struct value *arg1, int fieldno);
 380
 381 extern struct value *value_primitive_field (struct value *arg1, int offset,
 382                                             int fieldno,
 383                                             struct type *arg_type);
 384
 385
 386 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 387                                             int *);
 388
 389 extern struct value *value_full_object (struct value *, struct type *, int,
 390                                         int, int);
 391
 392 extern struct value *value_cast (struct type *type, struct value *arg2);
 393
 394 extern struct value *value_zero (struct type *type, enum lval_type lv);
 395
 396 extern struct value *value_repeat (struct value *arg1, int count);
 397
 398 extern struct value *value_subscript (struct value *array, struct value *idx);
 399
 400 extern struct value *register_value_being_returned (struct type *valtype,
 401                                                     struct regcache *retbuf);
 402
 403 extern struct value *value_in (struct value *element, struct value *set);
 404
 405 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 406                             int index);
 407
 408 extern int using_struct_return (struct type *value_type, int gcc_p);
 409
 410 extern struct value *evaluate_expression (struct expression *exp);
 411
 412 extern struct value *evaluate_type (struct expression *exp);
 413
 414 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 415                                                     int *, enum noside);
 416
 417 extern struct value *parse_and_eval (char *exp);
 418
 419 extern struct value *parse_to_comma_and_eval (char **expp);
 420
 421 extern struct type *parse_and_eval_type (char *p, int length);
 422
 423 extern CORE_ADDR parse_and_eval_address (char *exp);
 424
 425 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 426
 427 extern LONGEST parse_and_eval_long (char *exp);
 428
 429 extern struct value *access_value_history (int num);
 430
 431 extern struct value *value_of_internalvar (struct internalvar *var);
 432
 433 extern void set_internalvar (struct internalvar *var, struct value *val);
 434
 435 extern void set_internalvar_component (struct internalvar *var,
 436                                        int offset,
 437                                        int bitpos, int bitsize,
 438                                        struct value *newvalue);
 439
 440 extern struct internalvar *lookup_internalvar (char *name);
 441
 442 extern int value_equal (struct value *arg1, struct value *arg2);
 443
 444 extern int value_less (struct value *arg1, struct value *arg2);
 445
 446 extern int value_logical_not (struct value *arg1);
 447
 448 /* C++ */
 449
 450 extern struct value *value_of_this (int complain);
 451
 452 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 453                                     enum exp_opcode op,
 454                                     enum exp_opcode otherop,
 455                                     enum noside noside);
 456
 457 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 458                                    enum noside noside);
 459
 460 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 461                                      int j, struct type *type, int offset);
 462
 463 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 464                                  struct value *arg2);
 465
 466 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 467
 468 extern int destructor_name_p (const char *name, const struct type *type);
 469
 470 #define value_free(val) xfree (val)
 471
 472 extern void free_all_values (void);
 473
 474 extern void release_value (struct value *val);
 475
 476 extern int record_latest_value (struct value *val);
 477
 478 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 479                           int bitsize);
 480
 481 extern void type_print (struct type *type, char *varstring,
 482                         struct ui_file *stream, int show);
 483
 484 extern char *baseclass_addr (struct type *type, int index, char *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 bfd_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 bfd_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 val_print_string (CORE_ADDR addr, int len, int width,
 509                              struct ui_file *stream);
 510
 511 extern void print_variable_value (struct symbol *var,
 512                                   struct frame_info *frame,
 513                                   struct ui_file *stream);
 514
 515 extern int check_field (struct value *, const char *);
 516
 517 extern void typedef_print (struct type *type, struct symbol *news,
 518                            struct ui_file *stream);
 519
 520 extern char *internalvar_name (struct internalvar *var);
 521
 522 extern void clear_value_history (void);
 523
 524 extern void clear_internalvars (void);
 525
 526 /* From values.c */
 527
 528 extern struct value *value_copy (struct value *);
 529
 530 /* From valops.c */
 531
 532 extern struct value *varying_to_slice (struct value *);
 533
 534 extern struct value *value_slice (struct value *, int, int);
 535
 536 extern struct value *value_literal_complex (struct value *, struct value *,
 537                                             struct type *);
 538
 539 extern void find_rt_vbase_offset (struct type *, struct type *,
 540                                   const bfd_byte *, int, int *, int *);
 541
 542 extern struct value *find_function_in_inferior (const char *);
 543
 544 extern struct value *value_allocate_space_in_inferior (int);
 545
 546 extern struct value *value_of_local (const char *name, int complain);
 547
 548 #endif /* !defined (VALUE_H) */