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
   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
  62     /* Number of register.  Only used with lval_reg_frame_relative.  */
  63     int regnum;
  64   } location;
  65
  66   /* Describes offset of a value within lval of a structure in bytes.
  67      If lval == lval_memory, this is an offset to the address.
  68      If lval == lval_register, this is a further offset from
  69      location.address within the registers structure.
  70      Note also the member embedded_offset below.  */
  71   int offset;
  72
  73   /* Only used for bitfields; number of bits contained in them.  */
  74   int bitsize;
  75
  76   /* Only used for bitfields; position of start of field.
  77      For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  78      For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  79     int bitpos;
  80
  81   /* Frame value is relative to.  In practice, this ID is only used if
  82      the value is stored in several registers in other than the
  83      current frame, and these registers have not all been saved at the
  84      same place in memory.  This will be described in the lval enum
  85      above as "lval_reg_frame_relative".  */
  86   struct frame_id frame_id;
  87
  88   /* Type of the value.  */
  89   struct type *type;
  90
  91   /* If a value represents a C++ object, then the `type' field gives
  92      the object's compile-time type.  If the object actually belongs
  93      to some class derived from `type', perhaps with other base
  94      classes and additional members, then `type' is just a subobject
  95      of the real thing, and the full object is probably larger than
  96      `type' would suggest.
  97
  98      If `type' is a dynamic class (i.e. one with a vtable), then GDB
  99      can actually determine the object's run-time type by looking at
 100      the run-time type information in the vtable.  When this
 101      information is available, we may elect to read in the entire
 102      object, for several reasons:
 103
 104      - When printing the value, the user would probably rather see the
 105        full object, not just the limited portion apparent from the
 106        compile-time type.
 107
 108      - If `type' has virtual base classes, then even printing `type'
 109        alone may require reaching outside the `type' portion of the
 110        object to wherever the virtual base class has been stored.
 111
 112      When we store the entire object, `enclosing_type' is the run-time
 113      type -- the complete object -- and `embedded_offset' is the
 114      offset of `type' within that larger type, in bytes.  The
 115      VALUE_CONTENTS macro takes `embedded_offset' into account, so
 116      most GDB code continues to see the `type' portion of the value,
 117      just as the inferior would.
 118
 119      If `type' is a pointer to an object, then `enclosing_type' is a
 120      pointer to the object's run-time type, and `pointed_to_offset' is
 121      the offset in bytes from the full object to the pointed-to object
 122      -- that is, the value `embedded_offset' would have if we
 123      followed the pointer and fetched the complete object.  (I don't
 124      really see the point.  Why not just determine the run-time type
 125      when you indirect, and avoid the special case?  The contents
 126      don't matter until you indirect anyway.)
 127
 128      If we're not doing anything fancy, `enclosing_type' is equal to
 129      `type', and `embedded_offset' is zero, so everything works
 130      normally.  */
 131     struct type *enclosing_type;
 132     int embedded_offset;
 133     int pointed_to_offset;
 134
 135     /* Values are stored in a chain, so that they can be deleted
 136        easily over calls to the inferior.  Values assigned to internal
 137        variables or put into the value history are taken off this
 138        list.  */
 139     struct value *next;
 140
 141     /* Register number if the value is from a register.  */
 142     short regno;
 143
 144     /* If zero, contents of this value are in the contents field.  If
 145        nonzero, contents are in inferior memory at address in the
 146        location.address field plus the offset field (and the lval
 147        field should be lval_memory).
 148
 149        WARNING: This field is used by the code which handles
 150        watchpoints (see breakpoint.c) to decide whether a particular
 151        value can be watched by hardware watchpoints.  If the lazy flag
 152        is set for some member of a value chain, it is assumed that
 153        this member of the chain doesn't need to be watched as part of
 154        watching the value itself.  This is how GDB avoids watching the
 155        entire struct or array when the user wants to watch a single
 156        struct member or array element.  If you ever change the way
 157        lazy flag is set and reset, be sure to consider this use as
 158        well!  */
 159     char lazy;
 160
 161     /* If nonzero, this is the value of a variable which does not
 162        actually exist in the program.  */
 163     char optimized_out;
 164
 165     /* Actual contents of the value.  For use of this value; setting
 166        it uses the stuff above.  Not valid if lazy is nonzero.
 167        Target byte-order.  We force it to be aligned properly for any
 168        possible value.  Note that a value therefore extends beyond
 169        what is declared here.  */
 170     union
 171     {
 172       long contents[1];
 173       DOUBLEST force_doublest_align;
 174       LONGEST force_longest_align;
 175       CORE_ADDR force_core_addr_align;
 176       void *force_pointer_align;
 177     } aligner;
 178     /* Do not add any new members here -- contents above will trash them.  */
 179 };
 180
 181 #define VALUE_TYPE(val) (val)->type
 182 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 183 #define VALUE_LAZY(val) (val)->lazy
 184
 185 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 186    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_RAW is used when data is being stored into the
 191    buffer, or when it is certain that the contents of the buffer are
 192    valid.
 193
 194    Note: The contents pointer is adjusted by the offset required to
 195    get to the real subobject, if the value happens to represent
 196    something embedded in a larger run-time object.  */
 197
 198 #define VALUE_CONTENTS_RAW(val) \
 199  ((char *) (val)->aligner.contents + (val)->embedded_offset)
 200 #define VALUE_CONTENTS(val) \
 201  ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)), VALUE_CONTENTS_RAW(val))
 202
 203 /* The ALL variants of the above two macros do not adjust the returned
 204    pointer by the embedded_offset value.  */
 205
 206 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 207 #define VALUE_CONTENTS_ALL(val) \
 208   ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)), \
 209    VALUE_CONTENTS_ALL_RAW(val))
 210
 211 extern int value_fetch_lazy (struct value *val);
 212
 213 #define VALUE_LVAL(val) (val)->lval
 214 #define VALUE_ADDRESS(val) (val)->location.address
 215 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 216 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 217 #define VALUE_FRAME_ID(val) ((val)->frame_id)
 218 #define VALUE_OFFSET(val) (val)->offset
 219 #define VALUE_BITSIZE(val) (val)->bitsize
 220 #define VALUE_BITPOS(val) (val)->bitpos
 221 #define VALUE_NEXT(val) (val)->next
 222 #define VALUE_REGNO(val) (val)->regno
 223 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 224 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 225 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 226
 227 /* Convert a REF to the object referenced.  */
 228
 229 extern struct value *coerce_ref (struct value *value);
 230
 231 /* If ARG is an array, convert it to a pointer.
 232    If ARG is an enum, convert it to an integer.
 233    If ARG is a function, convert it to a function pointer.
 234
 235    References are dereferenced.  */
 236
 237 extern struct value *coerce_array (struct value *value);
 238 extern struct value *coerce_number (struct value *value);
 239
 240 /* If ARG is an enum, convert it to an integer.  */
 241
 242 extern struct value *coerce_enum (struct value *value);
 243
 244 /* Internal variables (variables for convenience of use of debugger)
 245    are recorded as a chain of these structures.  */
 246
 247 struct internalvar
 248 {
 249   struct internalvar *next;
 250   char *name;
 251   struct value *value;
 252 };
 253
 254 /* Pointer to member function.  Depends on compiler implementation.  */
 255
 256 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 257 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 258 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 259 \f
 260
 261 #include "symtab.h"
 262 #include "gdbtypes.h"
 263 #include "expression.h"
 264
 265 struct frame_info;
 266 struct fn_field;
 267
 268 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 269
 270 extern LONGEST value_as_long (struct value *val);
 271 extern DOUBLEST value_as_double (struct value *val);
 272 extern CORE_ADDR value_as_address (struct value *val);
 273
 274 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 275 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 276                                int *invp);
 277 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 278 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 279                                      int fieldno);
 280
 281 extern struct value *value_from_longest (struct type *type, LONGEST num);
 282 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 283 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 284 extern struct value *value_from_string (char *string);
 285
 286 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 287 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 288
 289 extern struct value *value_from_register (struct type *type, int regnum,
 290                                           struct frame_info *frame);
 291
 292 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 293
 294 extern struct value *value_of_register (int regnum,
 295                                         struct frame_info *frame);
 296
 297 extern int symbol_read_needs_frame (struct symbol *);
 298
 299 extern struct value *read_var_value (struct symbol *var,
 300                                      struct frame_info *frame);
 301
 302 extern struct value *locate_var_value (struct symbol *var,
 303                                        struct frame_info *frame);
 304
 305 extern struct value *allocate_value (struct type *type);
 306
 307 extern struct value *allocate_repeat_value (struct type *type, int count);
 308
 309 extern struct value *value_change_enclosing_type (struct value *val,
 310                                                   struct type *new_type);
 311
 312 extern struct value *value_mark (void);
 313
 314 extern void value_free_to_mark (struct value *mark);
 315
 316 extern struct value *value_string (char *ptr, int len);
 317 extern struct value *value_bitstring (char *ptr, int len);
 318
 319 extern struct value *value_array (int lowbound, int highbound,
 320                                   struct value ** elemvec);
 321
 322 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 323
 324 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 325                                   enum exp_opcode op);
 326
 327 extern struct value *value_add (struct value *arg1, struct value *arg2);
 328
 329 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 330
 331 extern struct value *value_coerce_array (struct value *arg1);
 332
 333 extern struct value *value_coerce_function (struct value *arg1);
 334
 335 extern struct value *value_ind (struct value *arg1);
 336
 337 extern struct value *value_addr (struct value *arg1);
 338
 339 extern struct value *value_assign (struct value *toval, struct value *fromval);
 340
 341 extern struct value *value_neg (struct value *arg1);
 342
 343 extern struct value *value_complement (struct value *arg1);
 344
 345 extern struct value *value_struct_elt (struct value **argp,
 346                                        struct value **args,
 347                                        char *name, int *static_memfuncp,
 348                                        char *err);
 349
 350 extern struct value *value_aggregate_elt (struct type *curtype,
 351                                           char *name,
 352                                           enum noside noside);
 353
 354 extern struct value *value_static_field (struct type *type, int fieldno);
 355
 356 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 357                                                       int, int *,
 358                                                       struct type **, int *);
 359
 360 extern int find_overload_match (struct type **arg_types, int nargs,
 361                                 char *name, int method, int lax,
 362                                 struct value **objp, struct symbol *fsym,
 363                                 struct value **valp, struct symbol **symp,
 364                                 int *staticp);
 365
 366 extern struct value *value_field (struct value *arg1, int fieldno);
 367
 368 extern struct value *value_primitive_field (struct value *arg1, int offset,
 369                                             int fieldno,
 370                                             struct type *arg_type);
 371
 372
 373 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 374                                             int *);
 375
 376 extern struct value *value_full_object (struct value *, struct type *, int,
 377                                         int, int);
 378
 379 extern struct value *value_cast (struct type *type, struct value *arg2);
 380
 381 extern struct value *value_zero (struct type *type, enum lval_type lv);
 382
 383 extern struct value *value_repeat (struct value *arg1, int count);
 384
 385 extern struct value *value_subscript (struct value *array, struct value *idx);
 386
 387 extern struct value *register_value_being_returned (struct type *valtype,
 388                                                     struct regcache *retbuf);
 389
 390 extern struct value *value_in (struct value *element, struct value *set);
 391
 392 extern int value_bit_index (struct type *type, char *addr, int index);
 393
 394 extern int using_struct_return (struct type *value_type, int gcc_p);
 395
 396 extern struct value *evaluate_expression (struct expression *exp);
 397
 398 extern struct value *evaluate_type (struct expression *exp);
 399
 400 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 401                                                     int *, enum noside);
 402
 403 extern struct value *parse_and_eval (char *exp);
 404
 405 extern struct value *parse_to_comma_and_eval (char **expp);
 406
 407 extern struct type *parse_and_eval_type (char *p, int length);
 408
 409 extern CORE_ADDR parse_and_eval_address (char *exp);
 410
 411 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 412
 413 extern LONGEST parse_and_eval_long (char *exp);
 414
 415 extern struct value *access_value_history (int num);
 416
 417 extern struct value *value_of_internalvar (struct internalvar *var);
 418
 419 extern void set_internalvar (struct internalvar *var, struct value *val);
 420
 421 extern void set_internalvar_component (struct internalvar *var,
 422                                        int offset,
 423                                        int bitpos, int bitsize,
 424                                        struct value *newvalue);
 425
 426 extern struct internalvar *lookup_internalvar (char *name);
 427
 428 extern int value_equal (struct value *arg1, struct value *arg2);
 429
 430 extern int value_less (struct value *arg1, struct value *arg2);
 431
 432 extern int value_logical_not (struct value *arg1);
 433
 434 /* C++ */
 435
 436 extern struct value *value_of_this (int complain);
 437
 438 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 439                                     enum exp_opcode op,
 440                                     enum exp_opcode otherop,
 441                                     enum noside noside);
 442
 443 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 444                                    enum noside noside);
 445
 446 extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
 447                                      int j, struct type *type, int offset);
 448
 449 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 450                                  struct value *arg2);
 451
 452 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 453
 454 extern int destructor_name_p (const char *name, const struct type *type);
 455
 456 #define value_free(val) xfree (val)
 457
 458 extern void free_all_values (void);
 459
 460 extern void release_value (struct value *val);
 461
 462 extern int record_latest_value (struct value *val);
 463
 464 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 465                           int bitsize);
 466
 467 extern void type_print (struct type * type, char *varstring,
 468                         struct ui_file * stream, int show);
 469
 470 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 471                              struct value **valuep, int *errp);
 472
 473 extern void print_longest (struct ui_file * stream, int format,
 474                            int use_local, LONGEST val);
 475
 476 extern void print_floating (char *valaddr, struct type * type,
 477                             struct ui_file * stream);
 478
 479 extern int value_print (struct value *val, struct ui_file *stream, int format,
 480                         enum val_prettyprint pretty);
 481
 482 extern void value_print_array_elements (struct value *val,
 483                                         struct ui_file *stream, int format,
 484                                         enum val_prettyprint pretty);
 485
 486 extern struct value *value_release_to_mark (struct value *mark);
 487
 488 extern int val_print (struct type * type, char *valaddr,
 489                       int embedded_offset, CORE_ADDR address,
 490                       struct ui_file * stream, int format,
 491                       int deref_ref, int recurse,
 492                       enum val_prettyprint pretty);
 493
 494 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 495
 496 extern void print_variable_value (struct symbol * var,
 497                                   struct frame_info * frame,
 498                                   struct ui_file *stream);
 499
 500 extern int check_field (struct value *, const char *);
 501
 502 extern void typedef_print (struct type * type, struct symbol * news,
 503                              struct ui_file * stream);
 504
 505 extern char *internalvar_name (struct internalvar *var);
 506
 507 extern void clear_value_history (void);
 508
 509 extern void clear_internalvars (void);
 510
 511 /* From values.c */
 512
 513 extern struct value *value_copy (struct value *);
 514
 515 /* From valops.c */
 516
 517 extern struct value *varying_to_slice (struct value *);
 518
 519 extern struct value *value_slice (struct value *, int, int);
 520
 521 extern struct value *value_literal_complex (struct value *, struct value *,
 522                                             struct type *);
 523
 524 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 525                                   int *, int *);
 526
 527 extern struct value *find_function_in_inferior (const char *);
 528
 529 extern struct value *value_allocate_space_in_inferior (int);
 530
 531 extern struct value *value_of_local (const char *name, int complain);
 532
 533 #endif /* !defined (VALUE_H) */