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   } 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.
  65      If lval == lval_register, this is a further offset from
  66      location.address within the registers structure.
  67      Note also the 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.
  74      For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  75      For 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
 117      followed the pointer and fetched the complete object.  (I don't
 118      really see the point.  Why not just determine the run-time type
 119      when you indirect, and avoid the special case?  The contents
 120      don't matter 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
 130        easily 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
 141        field should be lval_memory).
 142
 143        WARNING: This field is used by the code which handles
 144        watchpoints (see breakpoint.c) to decide whether a particular
 145        value can be watched by hardware watchpoints.  If the lazy flag
 146        is set for some member of a value chain, it is assumed that
 147        this member of the chain doesn't need to be watched as part of
 148        watching the value itself.  This is how GDB avoids watching the
 149        entire struct or array when the user wants to watch a single
 150        struct member or array element.  If you ever change the way
 151        lazy flag is set and reset, be sure to consider this use as
 152        well!  */
 153     char lazy;
 154
 155     /* If nonzero, this is the value of a variable which does not
 156        actually exist in the program.  */
 157     char optimized_out;
 158
 159     /* Actual contents of the value.  For use of this value; setting
 160        it uses the stuff above.  Not valid if lazy is nonzero.
 161        Target byte-order.  We force it to be aligned properly for any
 162        possible value.  Note that a value therefore extends beyond
 163        what is declared here.  */
 164     union
 165     {
 166       long contents[1];
 167       DOUBLEST force_doublest_align;
 168       LONGEST force_longest_align;
 169       CORE_ADDR force_core_addr_align;
 170       void *force_pointer_align;
 171     } aligner;
 172     /* Do not add any new members here -- contents above will trash 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 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 182 #define VALUE_LAZY(val) (val)->lazy
 183
 184 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 185    the gdb buffer used to hold a copy of the contents of the lval.
 186    VALUE_CONTENTS is used when the contents of the buffer are needed
 187    -- it uses value_fetch_lazy() to load the buffer from the process
 188    being debugged if it hasn't already been loaded.
 189    VALUE_CONTENTS_RAW is used when data is being stored into the
 190    buffer, or when it is certain that the contents of the buffer are
 191    valid.
 192
 193    Note: The contents pointer is adjusted by the offset required to
 194    get to the real subobject, if the value happens to represent
 195    something embedded in a larger run-time object.  */
 196
 197 #define VALUE_CONTENTS_RAW(val) \
 198  ((char *) (val)->aligner.contents + (val)->embedded_offset)
 199 #define VALUE_CONTENTS(val) \
 200  ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)), VALUE_CONTENTS_RAW(val))
 201
 202 /* The ALL variants of the above two macros do not adjust the returned
 203    pointer by the embedded_offset value.  */
 204
 205 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 206 #define VALUE_CONTENTS_ALL(val) \
 207   ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)), \
 208    VALUE_CONTENTS_ALL_RAW(val))
 209
 210 extern int value_fetch_lazy (struct value *val);
 211
 212 #define VALUE_LVAL(val) (val)->lval
 213 #define VALUE_ADDRESS(val) (val)->location.address
 214 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 215 #define VALUE_FRAME_ID(val) ((val)->frame_id)
 216 #define VALUE_REGNUM(val) (val)->regnum
 217 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 218 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 219 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 220
 221 /* Convert a REF to the object referenced.  */
 222
 223 extern struct value *coerce_ref (struct value *value);
 224
 225 /* If ARG is an array, convert it to a pointer.
 226    If ARG is an enum, convert it to an integer.
 227    If ARG is a function, convert it to a function pointer.
 228
 229    References are dereferenced.  */
 230
 231 extern struct value *coerce_array (struct value *value);
 232 extern struct value *coerce_number (struct value *value);
 233
 234 /* If ARG is an enum, convert it to an integer.  */
 235
 236 extern struct value *coerce_enum (struct value *value);
 237
 238 /* Internal variables (variables for convenience of use of debugger)
 239    are recorded as a chain of these structures.  */
 240
 241 struct internalvar
 242 {
 243   struct internalvar *next;
 244   char *name;
 245   struct value *value;
 246 };
 247
 248 /* Pointer to member function.  Depends on compiler implementation.  */
 249
 250 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 251 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 252 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 253 \f
 254
 255 #include "symtab.h"
 256 #include "gdbtypes.h"
 257 #include "expression.h"
 258
 259 struct frame_info;
 260 struct fn_field;
 261
 262 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 263
 264 extern LONGEST value_as_long (struct value *val);
 265 extern DOUBLEST value_as_double (struct value *val);
 266 extern CORE_ADDR value_as_address (struct value *val);
 267
 268 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 269 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 270                                int *invp);
 271 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 272 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 273                                      int fieldno);
 274
 275 extern struct value *value_from_longest (struct type *type, LONGEST num);
 276 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 277 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 278 extern struct value *value_from_string (char *string);
 279
 280 extern struct value *value_at (struct type *type, CORE_ADDR addr);
 281 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr);
 282
 283 extern struct value *value_from_register (struct type *type, int regnum,
 284                                           struct frame_info *frame);
 285
 286 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 287
 288 extern struct value *value_of_register (int regnum,
 289                                         struct frame_info *frame);
 290
 291 extern int symbol_read_needs_frame (struct symbol *);
 292
 293 extern struct value *read_var_value (struct symbol *var,
 294                                      struct frame_info *frame);
 295
 296 extern struct value *locate_var_value (struct symbol *var,
 297                                        struct frame_info *frame);
 298
 299 extern struct value *allocate_value (struct type *type);
 300
 301 extern struct value *allocate_repeat_value (struct type *type, int count);
 302
 303 extern struct value *value_change_enclosing_type (struct value *val,
 304                                                   struct type *new_type);
 305
 306 extern struct value *value_mark (void);
 307
 308 extern void value_free_to_mark (struct value *mark);
 309
 310 extern struct value *value_string (char *ptr, int len);
 311 extern struct value *value_bitstring (char *ptr, int len);
 312
 313 extern struct value *value_array (int lowbound, int highbound,
 314                                   struct value ** elemvec);
 315
 316 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 317
 318 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 319                                   enum exp_opcode op);
 320
 321 extern struct value *value_add (struct value *arg1, struct value *arg2);
 322
 323 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 324
 325 extern struct value *value_coerce_array (struct value *arg1);
 326
 327 extern struct value *value_coerce_function (struct value *arg1);
 328
 329 extern struct value *value_ind (struct value *arg1);
 330
 331 extern struct value *value_addr (struct value *arg1);
 332
 333 extern struct value *value_assign (struct value *toval, struct value *fromval);
 334
 335 extern struct value *value_neg (struct value *arg1);
 336
 337 extern struct value *value_complement (struct value *arg1);
 338
 339 extern struct value *value_struct_elt (struct value **argp,
 340                                        struct value **args,
 341                                        char *name, int *static_memfuncp,
 342                                        char *err);
 343
 344 extern struct value *value_aggregate_elt (struct type *curtype,
 345                                           char *name,
 346                                           enum noside noside);
 347
 348 extern struct value *value_static_field (struct type *type, int fieldno);
 349
 350 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 351                                                       int, int *,
 352                                                       struct type **, int *);
 353
 354 extern int find_overload_match (struct type **arg_types, int nargs,
 355                                 char *name, int method, int lax,
 356                                 struct value **objp, struct symbol *fsym,
 357                                 struct value **valp, struct symbol **symp,
 358                                 int *staticp);
 359
 360 extern struct value *value_field (struct value *arg1, int fieldno);
 361
 362 extern struct value *value_primitive_field (struct value *arg1, int offset,
 363                                             int fieldno,
 364                                             struct type *arg_type);
 365
 366
 367 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 368                                             int *);
 369
 370 extern struct value *value_full_object (struct value *, struct type *, int,
 371                                         int, int);
 372
 373 extern struct value *value_cast (struct type *type, struct value *arg2);
 374
 375 extern struct value *value_zero (struct type *type, enum lval_type lv);
 376
 377 extern struct value *value_repeat (struct value *arg1, int count);
 378
 379 extern struct value *value_subscript (struct value *array, struct value *idx);
 380
 381 extern struct value *register_value_being_returned (struct type *valtype,
 382                                                     struct regcache *retbuf);
 383
 384 extern struct value *value_in (struct value *element, struct value *set);
 385
 386 extern int value_bit_index (struct type *type, char *addr, int index);
 387
 388 extern int using_struct_return (struct type *value_type, int gcc_p);
 389
 390 extern struct value *evaluate_expression (struct expression *exp);
 391
 392 extern struct value *evaluate_type (struct expression *exp);
 393
 394 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 395                                                     int *, enum noside);
 396
 397 extern struct value *parse_and_eval (char *exp);
 398
 399 extern struct value *parse_to_comma_and_eval (char **expp);
 400
 401 extern struct type *parse_and_eval_type (char *p, int length);
 402
 403 extern CORE_ADDR parse_and_eval_address (char *exp);
 404
 405 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 406
 407 extern LONGEST parse_and_eval_long (char *exp);
 408
 409 extern struct value *access_value_history (int num);
 410
 411 extern struct value *value_of_internalvar (struct internalvar *var);
 412
 413 extern void set_internalvar (struct internalvar *var, struct value *val);
 414
 415 extern void set_internalvar_component (struct internalvar *var,
 416                                        int offset,
 417                                        int bitpos, int bitsize,
 418                                        struct value *newvalue);
 419
 420 extern struct internalvar *lookup_internalvar (char *name);
 421
 422 extern int value_equal (struct value *arg1, struct value *arg2);
 423
 424 extern int value_less (struct value *arg1, struct value *arg2);
 425
 426 extern int value_logical_not (struct value *arg1);
 427
 428 /* C++ */
 429
 430 extern struct value *value_of_this (int complain);
 431
 432 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 433                                     enum exp_opcode op,
 434                                     enum exp_opcode otherop,
 435                                     enum noside noside);
 436
 437 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 438                                    enum noside noside);
 439
 440 extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
 441                                      int j, struct type *type, int offset);
 442
 443 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 444                                  struct value *arg2);
 445
 446 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 447
 448 extern int destructor_name_p (const char *name, const struct type *type);
 449
 450 #define value_free(val) xfree (val)
 451
 452 extern void free_all_values (void);
 453
 454 extern void release_value (struct value *val);
 455
 456 extern int record_latest_value (struct value *val);
 457
 458 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 459                           int bitsize);
 460
 461 extern void type_print (struct type * type, char *varstring,
 462                         struct ui_file * stream, int show);
 463
 464 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 465                              struct value **valuep, int *errp);
 466
 467 extern void print_longest (struct ui_file * stream, int format,
 468                            int use_local, LONGEST val);
 469
 470 extern void print_floating (char *valaddr, struct type * type,
 471                             struct ui_file * stream);
 472
 473 extern int value_print (struct value *val, struct ui_file *stream, int format,
 474                         enum val_prettyprint pretty);
 475
 476 extern void value_print_array_elements (struct value *val,
 477                                         struct ui_file *stream, int format,
 478                                         enum val_prettyprint pretty);
 479
 480 extern struct value *value_release_to_mark (struct value *mark);
 481
 482 extern int val_print (struct type * type, char *valaddr,
 483                       int embedded_offset, CORE_ADDR address,
 484                       struct ui_file * stream, int format,
 485                       int deref_ref, int recurse,
 486                       enum val_prettyprint pretty);
 487
 488 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 489
 490 extern void print_variable_value (struct symbol * var,
 491                                   struct frame_info * frame,
 492                                   struct ui_file *stream);
 493
 494 extern int check_field (struct value *, const char *);
 495
 496 extern void typedef_print (struct type * type, struct symbol * news,
 497                              struct ui_file * stream);
 498
 499 extern char *internalvar_name (struct internalvar *var);
 500
 501 extern void clear_value_history (void);
 502
 503 extern void clear_internalvars (void);
 504
 505 /* From values.c */
 506
 507 extern struct value *value_copy (struct value *);
 508
 509 /* From valops.c */
 510
 511 extern struct value *varying_to_slice (struct value *);
 512
 513 extern struct value *value_slice (struct value *, int, int);
 514
 515 extern struct value *value_literal_complex (struct value *, struct value *,
 516                                             struct type *);
 517
 518 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 519                                   int *, int *);
 520
 521 extern struct value *find_function_in_inferior (const char *);
 522
 523 extern struct value *value_allocate_space_in_inferior (int);
 524
 525 extern struct value *value_of_local (const char *name, int complain);
 526
 527 #endif /* !defined (VALUE_H) */