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
 176 extern struct type *value_type (struct value *);
 177 extern int value_bitsize (struct value *);
 178 extern int value_bitpos (struct value *);
 179 extern int value_offset (struct value *);
 180
 181 extern struct type *value_enclosing_type (struct value *);
 182 extern int value_lazy (struct value *);
 183 extern void set_value_lazy (struct value *value, int val);
 184
 185 /* value_contents() and value_contents_raw() both return the address
 186    of the gdb buffer used to hold a copy of the contents of the lval.
 187    value_contents() is used when the contents of the buffer are needed
 188    -- it uses value_fetch_lazy() to load the buffer from the process
 189    being debugged if it hasn't already been loaded
 190    (value_contents_writeable() is used when a writeable but fetched
 191    buffer is required)..  value_contents_raw() is used when data is
 192    being stored into the buffer, or when it is certain that the
 193    contents of the buffer are valid.
 194
 195    Note: The contents pointer is adjusted by the offset required to
 196    get to the real subobject, if the value happens to represent
 197    something embedded in a larger run-time object.  */
 198
 199 extern bfd_byte *value_contents_raw (struct value *);
 200 extern const bfd_byte *value_contents (struct value *);
 201 extern bfd_byte *value_contents_writeable (struct value *);
 202
 203 /* The ALL variants of the above two macros do not adjust the returned
 204    pointer by the embedded_offset value.  */
 205
 206 extern bfd_byte *value_contents_all_raw (struct value *);
 207 extern const bfd_byte *value_contents_all (struct value *);
 208
 209 extern int value_fetch_lazy (struct value *val);
 210
 211 #define VALUE_LVAL(val) (val)->lval
 212 #define VALUE_ADDRESS(val) (val)->location.address
 213 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 214 #define VALUE_FRAME_ID(val) ((val)->frame_id)
 215 #define VALUE_REGNUM(val) (val)->regnum
 216 extern int value_optimized_out (struct value *value);
 217 extern void set_value_optimized_out (struct value *value, int val);
 218 extern int value_embedded_offset (struct value *value);
 219 extern void set_value_embedded_offset (struct value *value, int val);
 220 extern int value_pointed_to_offset (struct value *value);
 221 extern void set_value_pointed_to_offset (struct value *value, int val);
 222
 223 /* Convert a REF to the object referenced.  */
 224
 225 extern struct value *coerce_ref (struct value *value);
 226
 227 /* If ARG is an array, convert it to a pointer.
 228    If ARG is an enum, convert it to an integer.
 229    If ARG is a function, convert it to a function pointer.
 230
 231    References are dereferenced.  */
 232
 233 extern struct value *coerce_array (struct value *value);
 234 extern struct value *coerce_number (struct value *value);
 235
 236 /* If ARG is an enum, convert it to an integer.  */
 237
 238 extern struct value *coerce_enum (struct value *value);
 239
 240 /* Internal variables (variables for convenience of use of debugger)
 241    are recorded as a chain of these structures.  */
 242
 243 struct internalvar
 244 {
 245   struct internalvar *next;
 246   char *name;
 247   struct value *value;
 248 };
 249
 250 /* Pointer to member function.  Depends on compiler implementation.  */
 251
 252 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 253 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 254 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 255 \f
 256
 257 #include "symtab.h"
 258 #include "gdbtypes.h"
 259 #include "expression.h"
 260
 261 struct frame_info;
 262 struct fn_field;
 263
 264 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 265
 266 extern LONGEST value_as_long (struct value *val);
 267 extern DOUBLEST value_as_double (struct value *val);
 268 extern CORE_ADDR value_as_address (struct value *val);
 269
 270 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 271 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 272                                int *invp);
 273 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 274 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 275                                      int fieldno);
 276
 277 extern struct value *value_from_longest (struct type *type, LONGEST num);
 278 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 279 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 280 extern struct value *value_from_string (char *string);
 281
 282 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 283 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 284
 285 extern struct value *value_from_register (struct type *type, int regnum,
 286                                           struct frame_info *frame);
 287
 288 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 289
 290 extern struct value *value_of_register (int regnum, struct frame_info *frame);
 291
 292 extern int symbol_read_needs_frame (struct symbol *);
 293
 294 extern struct value *read_var_value (struct symbol *var,
 295                                      struct frame_info *frame);
 296
 297 extern struct value *locate_var_value (struct symbol *var,
 298                                        struct frame_info *frame);
 299
 300 extern struct value *allocate_value (struct type *type);
 301
 302 extern struct value *allocate_repeat_value (struct type *type, int count);
 303
 304 extern struct value *value_change_enclosing_type (struct value *val,
 305                                                   struct type *new_type);
 306
 307 extern struct value *value_mark (void);
 308
 309 extern void value_free_to_mark (struct value *mark);
 310
 311 extern struct value *value_string (char *ptr, int len);
 312 extern struct value *value_bitstring (char *ptr, int len);
 313
 314 extern struct value *value_array (int lowbound, int highbound,
 315                                   struct value **elemvec);
 316
 317 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 318
 319 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 320                                   enum exp_opcode op);
 321
 322 extern struct value *value_add (struct value *arg1, struct value *arg2);
 323
 324 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 325
 326 extern struct value *value_coerce_array (struct value *arg1);
 327
 328 extern struct value *value_coerce_function (struct value *arg1);
 329
 330 extern struct value *value_ind (struct value *arg1);
 331
 332 extern struct value *value_addr (struct value *arg1);
 333
 334 extern struct value *value_assign (struct value *toval,
 335                                    struct value *fromval);
 336
 337 extern struct value *value_neg (struct value *arg1);
 338
 339 extern struct value *value_complement (struct value *arg1);
 340
 341 extern struct value *value_struct_elt (struct value **argp,
 342                                        struct value **args,
 343                                        char *name, int *static_memfuncp,
 344                                        char *err);
 345
 346 extern struct value *value_aggregate_elt (struct type *curtype,
 347                                           char *name, enum noside noside);
 348
 349 extern struct value *value_static_field (struct type *type, int fieldno);
 350
 351 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 352                                                       int, int *,
 353                                                       struct type **, int *);
 354
 355 extern int find_overload_match (struct type **arg_types, int nargs,
 356                                 char *name, int method, int lax,
 357                                 struct value **objp, struct symbol *fsym,
 358                                 struct value **valp, struct symbol **symp,
 359                                 int *staticp);
 360
 361 extern struct value *value_field (struct value *arg1, int fieldno);
 362
 363 extern struct value *value_primitive_field (struct value *arg1, int offset,
 364                                             int fieldno,
 365                                             struct type *arg_type);
 366
 367
 368 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 369                                             int *);
 370
 371 extern struct value *value_full_object (struct value *, struct type *, int,
 372                                         int, int);
 373
 374 extern struct value *value_cast (struct type *type, struct value *arg2);
 375
 376 extern struct value *value_zero (struct type *type, enum lval_type lv);
 377
 378 extern struct value *value_repeat (struct value *arg1, int count);
 379
 380 extern struct value *value_subscript (struct value *array, struct value *idx);
 381
 382 extern struct value *register_value_being_returned (struct type *valtype,
 383                                                     struct regcache *retbuf);
 384
 385 extern struct value *value_in (struct value *element, struct value *set);
 386
 387 extern int value_bit_index (struct type *type, const bfd_byte *addr,
 388                             int index);
 389
 390 extern int using_struct_return (struct type *value_type, int gcc_p);
 391
 392 extern struct value *evaluate_expression (struct expression *exp);
 393
 394 extern struct value *evaluate_type (struct expression *exp);
 395
 396 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 397                                                     int *, enum noside);
 398
 399 extern struct value *parse_and_eval (char *exp);
 400
 401 extern struct value *parse_to_comma_and_eval (char **expp);
 402
 403 extern struct type *parse_and_eval_type (char *p, int length);
 404
 405 extern CORE_ADDR parse_and_eval_address (char *exp);
 406
 407 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 408
 409 extern LONGEST parse_and_eval_long (char *exp);
 410
 411 extern struct value *access_value_history (int num);
 412
 413 extern struct value *value_of_internalvar (struct internalvar *var);
 414
 415 extern void set_internalvar (struct internalvar *var, struct value *val);
 416
 417 extern void set_internalvar_component (struct internalvar *var,
 418                                        int offset,
 419                                        int bitpos, int bitsize,
 420                                        struct value *newvalue);
 421
 422 extern struct internalvar *lookup_internalvar (char *name);
 423
 424 extern int value_equal (struct value *arg1, struct value *arg2);
 425
 426 extern int value_less (struct value *arg1, struct value *arg2);
 427
 428 extern int value_logical_not (struct value *arg1);
 429
 430 /* C++ */
 431
 432 extern struct value *value_of_this (int complain);
 433
 434 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 435                                     enum exp_opcode op,
 436                                     enum exp_opcode otherop,
 437                                     enum noside noside);
 438
 439 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 440                                    enum noside noside);
 441
 442 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f,
 443                                      int j, struct type *type, int offset);
 444
 445 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 446                                  struct value *arg2);
 447
 448 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 449
 450 extern int destructor_name_p (const char *name, const struct type *type);
 451
 452 #define value_free(val) xfree (val)
 453
 454 extern void free_all_values (void);
 455
 456 extern void release_value (struct value *val);
 457
 458 extern int record_latest_value (struct value *val);
 459
 460 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 461                           int bitsize);
 462
 463 extern void type_print (struct type *type, char *varstring,
 464                         struct ui_file *stream, int show);
 465
 466 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 467                              struct value **valuep, int *errp);
 468
 469 extern void print_longest (struct ui_file *stream, int format,
 470                            int use_local, LONGEST val);
 471
 472 extern void print_floating (const bfd_byte *valaddr, struct type *type,
 473                             struct ui_file *stream);
 474
 475 extern int value_print (struct value *val, struct ui_file *stream, int format,
 476                         enum val_prettyprint pretty);
 477
 478 extern void value_print_array_elements (struct value *val,
 479                                         struct ui_file *stream, int format,
 480                                         enum val_prettyprint pretty);
 481
 482 extern struct value *value_release_to_mark (struct value *mark);
 483
 484 extern int val_print (struct type *type, const bfd_byte *valaddr,
 485                       int embedded_offset, CORE_ADDR address,
 486                       struct ui_file *stream, int format,
 487                       int deref_ref, int recurse,
 488                       enum val_prettyprint pretty);
 489
 490 extern int val_print_string (CORE_ADDR addr, int len, int width,
 491                              struct ui_file *stream);
 492
 493 extern void print_variable_value (struct symbol *var,
 494                                   struct frame_info *frame,
 495                                   struct ui_file *stream);
 496
 497 extern int check_field (struct value *, const char *);
 498
 499 extern void typedef_print (struct type *type, struct symbol *news,
 500                            struct ui_file *stream);
 501
 502 extern char *internalvar_name (struct internalvar *var);
 503
 504 extern void clear_value_history (void);
 505
 506 extern void clear_internalvars (void);
 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 bfd_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) */