gdb/value.h

   1 /* Definitions for values of C expressions, for GDB.
   2    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
   3    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003
   4    Free Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #if !defined (VALUE_H)
  24 #define VALUE_H 1
  25
  26 struct regcache;
  27
  28 #include "doublest.h"
  29
  30 /*
  31  * The structure which defines the type of a value.  It should never
  32  * be possible for a program lval value to survive over a call to the inferior
  33  * (ie to be put into the history list or an internal variable).
  34  */
  35
  36 struct value
  37   {
  38     /* Type of value; either not an lval, or one of the various
  39        different possible kinds of lval.  */
  40     enum lval_type lval;
  41     /* Is it modifiable?  Only relevant if lval != not_lval.  */
  42     int modifiable;
  43     /* Location of value (if lval).  */
  44     union
  45       {
  46         /* If lval == lval_memory, this is the address in the inferior.
  47            If lval == lval_register, this is the byte offset into the
  48            registers structure.  */
  49         CORE_ADDR address;
  50         /* Pointer to internal variable.  */
  51         struct internalvar *internalvar;
  52         /* Number of register.  Only used with
  53            lval_reg_frame_relative.  */
  54         int regnum;
  55       }
  56     location;
  57     /* Describes offset of a value within lval of a structure in bytes.
  58        If lval == lval_memory, this is an offset to the address.
  59        If lval == lval_register, this is a further offset from
  60           location.address within the registers structure.
  61        Note also the member embedded_offset below.  */
  62     int offset;
  63     /* Only used for bitfields; number of bits contained in them.  */
  64     int bitsize;
  65     /* Only used for bitfields; position of start of field.
  66        For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  67        For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  68     int bitpos;
  69     /* Frame value is relative to.  In practice, this address is only
  70        used if the value is stored in several registers in other than
  71        the current frame, and these registers have not all been saved
  72        at the same place in memory.  This will be described in the
  73        lval enum above as "lval_reg_frame_relative".  */
  74     CORE_ADDR frame_addr;
  75
  76     /* Type of the value.  */
  77     struct type *type;
  78
  79     /* If a value represents a C++ object, then the `type' field gives
  80        the object's compile-time type.  If the object actually belongs
  81        to some class derived from `type', perhaps with other base
  82        classes and additional members, then `type' is just a subobject
  83        of the real thing, and the full object is probably larger than
  84        `type' would suggest.
  85
  86        If `type' is a dynamic class (i.e. one with a vtable), then GDB
  87        can actually determine the object's run-time type by looking at
  88        the run-time type information in the vtable.  When this
  89        information is available, we may elect to read in the entire
  90        object, for several reasons:
  91
  92          - When printing the value, the user would probably rather see
  93            the full object, not just the limited portion apparent from
  94            the compile-time type.
  95
  96          - If `type' has virtual base classes, then even printing
  97            `type' alone may require reaching outside the `type'
  98            portion of the object to wherever the virtual base class
  99            has been stored.
 100
 101        When we store the entire object, `enclosing_type' is the
 102        run-time type --- the complete object --- and `embedded_offset'
 103        is the offset of `type' within that larger type, in bytes.  The
 104        VALUE_CONTENTS macro takes `embedded_offset' into account, so
 105        most GDB code continues to see the `type' portion of the value,
 106        just as the inferior would.
 107
 108        If `type' is a pointer to an object, then `enclosing_type' is a
 109        pointer to the object's run-time type, and `pointed_to_offset'
 110        is the offset in bytes from the full object to the pointed-to
 111        object --- that is, the value `embedded_offset' would have if
 112        we followed the pointer and fetched the complete object.  (I
 113        don't really see the point.  Why not just determine the
 114        run-time type when you indirect, and avoid the special case?
 115        The contents don't matter until you indirect anyway.)
 116
 117        If we're not doing anything fancy, `enclosing_type' is equal to
 118        `type', and `embedded_offset' is zero, so everything works
 119        normally.  */
 120     struct type *enclosing_type;
 121     int embedded_offset;
 122     int pointed_to_offset;
 123
 124     /* Values are stored in a chain, so that they can be deleted
 125        easily over calls to the inferior.  Values assigned to internal
 126        variables or put into the value history are taken off this
 127        list.  */
 128     struct value *next;
 129
 130     /* Register number if the value is from a register.  Is not kept
 131        if you take a field of a structure that is stored in a
 132        register.  Shouldn't it be?  */
 133     short regno;
 134     /* If zero, contents of this value are in the contents field.
 135        If nonzero, contents are in inferior memory at address
 136        in the location.address field plus the offset field
 137        (and the lval field should be lval_memory).
 138
 139        WARNING: This field is used by the code which handles
 140        watchpoints (see breakpoint.c) to decide whether a particular
 141        value can be watched by hardware watchpoints.  If the lazy flag
 142        is set for some member of a value chain, it is assumed that
 143        this member of the chain doesn't need to be watched as part of
 144        watching the value itself.  This is how GDB avoids watching the
 145        entire struct or array when the user wants to watch a single
 146        struct member or array element.  If you ever change the way
 147        lazy flag is set and reset, be sure to consider this use as
 148        well!  */
 149     char lazy;
 150     /* If nonzero, this is the value of a variable which does not
 151        actually exist in the program.  */
 152     char optimized_out;
 153     /* The BFD section associated with this value.  */
 154     asection *bfd_section;
 155     /* Actual contents of the value.  For use of this value; setting
 156        it uses the stuff above.  Not valid if lazy is nonzero.
 157        Target byte-order.  We force it to be aligned properly for any
 158        possible value.  Note that a value therefore extends beyond
 159        what is declared here.  */
 160     union
 161       {
 162         long contents[1];
 163         DOUBLEST force_doublest_align;
 164         LONGEST force_longest_align;
 165         CORE_ADDR force_core_addr_align;
 166         void *force_pointer_align;
 167       }
 168     aligner;
 169     /* Do not add any new members here -- contents above will trash them */
 170   };
 171
 172 #define VALUE_TYPE(val) (val)->type
 173 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 174 #define VALUE_LAZY(val) (val)->lazy
 175 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 176    the gdb buffer used to hold a copy of the contents of the lval.
 177    VALUE_CONTENTS is used when the contents of the buffer are needed --
 178    it uses value_fetch_lazy() to load the buffer from the process being
 179    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 180    used when data is being stored into the buffer, or when it is
 181    certain that the contents of the buffer are valid.
 182    Note: The contents pointer is adjusted by the offset required to
 183    get to the real subobject, if the value happens to represent
 184    something embedded in a larger run-time object. */
 185
 186 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 187 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 188                              VALUE_CONTENTS_RAW(val))
 189
 190 /* The ALL variants of the above two macros do not adjust the returned
 191    pointer by the embedded_offset value. */
 192
 193 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 194 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 195                                  VALUE_CONTENTS_ALL_RAW(val))
 196
 197
 198 extern int value_fetch_lazy (struct value *val);
 199
 200 #define VALUE_LVAL(val) (val)->lval
 201 #define VALUE_ADDRESS(val) (val)->location.address
 202 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 203 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 204 #define VALUE_FRAME(val) ((val)->frame_addr)
 205 #define VALUE_OFFSET(val) (val)->offset
 206 #define VALUE_BITSIZE(val) (val)->bitsize
 207 #define VALUE_BITPOS(val) (val)->bitpos
 208 #define VALUE_NEXT(val) (val)->next
 209 #define VALUE_REGNO(val) (val)->regno
 210 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 211 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 212 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 213 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 214
 215 /* Convert a REF to the object referenced. */
 216
 217 #define COERCE_REF(arg)    \
 218 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 219      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 220          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 221                               unpack_pointer (VALUE_TYPE (arg),         \
 222                                               VALUE_CONTENTS (arg)),    \
 223                               VALUE_BFD_SECTION (arg));                 \
 224     } while (0)
 225
 226 /* If ARG is an array, convert it to a pointer.
 227    If ARG is an enum, convert it to an integer.
 228    If ARG is a function, convert it to a function pointer.
 229
 230    References are dereferenced.  */
 231
 232 #define COERCE_ARRAY(arg)    \
 233 do { COERCE_REF(arg);                                                   \
 234   if (current_language->c_style_arrays                                  \
 235       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 236     arg = value_coerce_array (arg);                                     \
 237   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 238     arg = value_coerce_function (arg);                                  \
 239 } while (0)
 240
 241 #define COERCE_NUMBER(arg)  \
 242   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 243
 244 /* NOTE: cagney/2002-12-17: This macro was handling a chill language
 245    problem but that language has gone away.  */
 246 #define COERCE_VARYING_ARRAY(arg, real_arg_type)
 247
 248 /* If ARG is an enum, convert it to an integer.  */
 249
 250 #define COERCE_ENUM(arg)   { \
 251   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 252     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 253 }
 254
 255 /* Internal variables (variables for convenience of use of debugger)
 256    are recorded as a chain of these structures.  */
 257
 258 struct internalvar
 259   {
 260     struct internalvar *next;
 261     char *name;
 262     struct value *value;
 263   };
 264
 265 /* Pointer to member function.  Depends on compiler implementation. */
 266
 267 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 268 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 269 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 270 \f
 271
 272 #include "symtab.h"
 273 #include "gdbtypes.h"
 274 #include "expression.h"
 275
 276 struct frame_info;
 277 struct fn_field;
 278
 279 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 280
 281 extern LONGEST value_as_long (struct value *val);
 282
 283 extern DOUBLEST value_as_double (struct value *val);
 284
 285 extern CORE_ADDR value_as_address (struct value *val);
 286
 287 extern LONGEST unpack_long (struct type *type, char *valaddr);
 288
 289 extern DOUBLEST unpack_double (struct type *type, char *valaddr, int *invp);
 290
 291 extern CORE_ADDR unpack_pointer (struct type *type, char *valaddr);
 292
 293 extern LONGEST unpack_field_as_long (struct type *type, char *valaddr,
 294                                      int fieldno);
 295
 296 extern struct value *value_from_longest (struct type *type, LONGEST num);
 297
 298 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 299
 300 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 301
 302 extern struct value *value_from_string (char *string);
 303
 304 extern struct value *value_at (struct type *type, CORE_ADDR addr,
 305                                asection * sect);
 306
 307 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
 308                                     asection * sect);
 309
 310 extern struct value *value_from_register (struct type *type, int regnum,
 311                                           struct frame_info *frame);
 312
 313 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 314
 315 extern struct value *value_of_register (int regnum,
 316                                         struct frame_info *frame);
 317
 318 extern int symbol_read_needs_frame (struct symbol *);
 319
 320 extern struct value *read_var_value (struct symbol *var,
 321                                      struct frame_info *frame);
 322
 323 extern struct value *locate_var_value (struct symbol *var,
 324                                        struct frame_info *frame);
 325
 326 extern struct value *allocate_value (struct type *type);
 327
 328 extern struct value *allocate_repeat_value (struct type *type, int count);
 329
 330 extern struct value *value_change_enclosing_type (struct value *val,
 331                                                   struct type *new_type);
 332
 333 extern struct value *value_mark (void);
 334
 335 extern void value_free_to_mark (struct value *mark);
 336
 337 extern struct value *value_string (char *ptr, int len);
 338 extern struct value *value_bitstring (char *ptr, int len);
 339
 340 extern struct value *value_array (int lowbound, int highbound,
 341                                   struct value ** elemvec);
 342
 343 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 344
 345 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 346                                   enum exp_opcode op);
 347
 348 extern struct value *value_add (struct value *arg1, struct value *arg2);
 349
 350 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 351
 352 extern struct value *value_coerce_array (struct value *arg1);
 353
 354 extern struct value *value_coerce_function (struct value *arg1);
 355
 356 extern struct value *value_ind (struct value *arg1);
 357
 358 extern struct value *value_addr (struct value *arg1);
 359
 360 extern struct value *value_assign (struct value *toval, struct value *fromval);
 361
 362 extern struct value *value_neg (struct value *arg1);
 363
 364 extern struct value *value_complement (struct value *arg1);
 365
 366 extern struct value *value_struct_elt (struct value **argp,
 367                                        struct value **args,
 368                                        char *name, int *static_memfuncp,
 369                                        char *err);
 370
 371 extern struct value *value_struct_elt_for_reference (struct type *domain,
 372                                                      int offset,
 373                                                      struct type *curtype,
 374                                                      char *name,
 375                                                      struct type *intype);
 376
 377 extern struct value *value_static_field (struct type *type, int fieldno);
 378
 379 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 380                                                       int, int *,
 381                                                       struct type **, int *);
 382
 383 extern int find_overload_match (struct type **arg_types, int nargs,
 384                                 char *name, int method, int lax,
 385                                 struct value **objp, struct symbol *fsym,
 386                                 struct value **valp, struct symbol **symp,
 387                                 int *staticp);
 388
 389 extern struct value *value_field (struct value *arg1, int fieldno);
 390
 391 extern struct value *value_primitive_field (struct value *arg1, int offset,
 392                                             int fieldno,
 393                                             struct type *arg_type);
 394
 395
 396 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 397                                             int *);
 398
 399 extern struct value *value_full_object (struct value *, struct type *, int,
 400                                         int, int);
 401
 402 extern struct value *value_cast (struct type *type, struct value *arg2);
 403
 404 extern struct value *value_zero (struct type *type, enum lval_type lv);
 405
 406 extern struct value *value_repeat (struct value *arg1, int count);
 407
 408 extern struct value *value_subscript (struct value *array, struct value *idx);
 409
 410 extern struct value *value_being_returned (struct type *valtype,
 411                                            struct regcache *retbuf,
 412                                            int struct_return);
 413
 414 extern struct value *value_in (struct value *element, struct value *set);
 415
 416 extern int value_bit_index (struct type *type, char *addr, int index);
 417
 418 extern int using_struct_return (struct value *function, CORE_ADDR funcaddr,
 419                                 struct type *value_type, int gcc_p);
 420
 421 extern void set_return_value (struct value *val);
 422
 423 extern struct value *evaluate_expression (struct expression *exp);
 424
 425 extern struct value *evaluate_type (struct expression *exp);
 426
 427 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 428                                                     int *, enum noside);
 429
 430 extern struct value *parse_and_eval (char *exp);
 431
 432 extern struct value *parse_to_comma_and_eval (char **expp);
 433
 434 extern struct type *parse_and_eval_type (char *p, int length);
 435
 436 extern CORE_ADDR parse_and_eval_address (char *exp);
 437
 438 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 439
 440 extern LONGEST parse_and_eval_long (char *exp);
 441
 442 extern struct value *access_value_history (int num);
 443
 444 extern struct value *value_of_internalvar (struct internalvar *var);
 445
 446 extern void set_internalvar (struct internalvar *var, struct value *val);
 447
 448 extern void set_internalvar_component (struct internalvar *var,
 449                                        int offset,
 450                                        int bitpos, int bitsize,
 451                                        struct value *newvalue);
 452
 453 extern struct internalvar *lookup_internalvar (char *name);
 454
 455 extern int value_equal (struct value *arg1, struct value *arg2);
 456
 457 extern int value_less (struct value *arg1, struct value *arg2);
 458
 459 extern int value_logical_not (struct value *arg1);
 460
 461 /* C++ */
 462
 463 extern struct value *value_of_this (int complain);
 464
 465 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 466                                     enum exp_opcode op,
 467                                     enum exp_opcode otherop,
 468                                     enum noside noside);
 469
 470 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 471                                    enum noside noside);
 472
 473 extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
 474                                      int j, struct type *type, int offset);
 475
 476 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 477                                  struct value *arg2);
 478
 479 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 480
 481 extern int destructor_name_p (const char *name, const struct type *type);
 482
 483 #define value_free(val) xfree (val)
 484
 485 extern void free_all_values (void);
 486
 487 extern void release_value (struct value *val);
 488
 489 extern int record_latest_value (struct value *val);
 490
 491 extern void
 492 modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize);
 493
 494 extern void type_print (struct type * type, char *varstring,
 495                         struct ui_file * stream, int show);
 496
 497 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 498                              struct value **valuep, int *errp);
 499
 500 extern void print_longest (struct ui_file * stream, int format,
 501                            int use_local, LONGEST val);
 502
 503 extern void print_floating (char *valaddr, struct type * type,
 504                             struct ui_file * stream);
 505
 506 extern int value_print (struct value *val, struct ui_file *stream, int format,
 507                         enum val_prettyprint pretty);
 508
 509 extern void value_print_array_elements (struct value *val,
 510                                         struct ui_file *stream, int format,
 511                                         enum val_prettyprint pretty);
 512
 513 extern struct value *value_release_to_mark (struct value *mark);
 514
 515 extern int val_print (struct type * type, char *valaddr,
 516                       int embedded_offset, CORE_ADDR address,
 517                       struct ui_file * stream, int format,
 518                       int deref_ref, int recurse,
 519                       enum val_prettyprint pretty);
 520
 521 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 522
 523 extern void print_variable_value (struct symbol * var,
 524                                   struct frame_info * frame,
 525                                   struct ui_file *stream);
 526
 527 extern int check_field (struct value *, const char *);
 528
 529 extern void typedef_print (struct type * type, struct symbol * news,
 530                              struct ui_file * stream);
 531
 532 extern char *internalvar_name (struct internalvar *var);
 533
 534 extern void clear_value_history (void);
 535
 536 extern void clear_internalvars (void);
 537
 538 /* From values.c */
 539
 540 extern struct value *value_copy (struct value *);
 541
 542 /* From valops.c */
 543
 544 extern struct value *varying_to_slice (struct value *);
 545
 546 extern struct value *value_slice (struct value *, int, int);
 547
 548 extern struct value *call_function_by_hand (struct value *, int,
 549                                             struct value **);
 550
 551 extern struct value *value_literal_complex (struct value *, struct value *,
 552                                             struct type *);
 553
 554 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 555                                   int *, int *);
 556
 557 extern struct value *find_function_in_inferior (const char *);
 558
 559 extern struct value *value_allocate_space_in_inferior (int);
 560
 561 extern CORE_ADDR default_push_arguments (int nargs, struct value ** args,
 562                                          CORE_ADDR sp, int struct_return,
 563                                          CORE_ADDR struct_addr);
 564
 565 extern struct value *value_of_local (const char *name, int complain);
 566
 567 #endif /* !defined (VALUE_H) */