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
   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 #include "doublest.h"
  27
  28 /*
  29  * The structure which defines the type of a value.  It should never
  30  * be possible for a program lval value to survive over a call to the inferior
  31  * (ie to be put into the history list or an internal variable).
  32  */
  33
  34 struct value
  35   {
  36     /* Type of value; either not an lval, or one of the various
  37        different possible kinds of lval.  */
  38     enum lval_type lval;
  39     /* Is it modifiable?  Only relevant if lval != not_lval.  */
  40     int modifiable;
  41     /* Location of value (if lval).  */
  42     union
  43       {
  44         /* If lval == lval_memory, this is the address in the inferior.
  45            If lval == lval_register, this is the byte offset into the
  46            registers structure.  */
  47         CORE_ADDR address;
  48         /* Pointer to internal variable.  */
  49         struct internalvar *internalvar;
  50         /* Number of register.  Only used with
  51            lval_reg_frame_relative.  */
  52         int regnum;
  53       }
  54     location;
  55     /* Describes offset of a value within lval of a structure in bytes.
  56        If lval == lval_memory, this is an offset to the address.
  57        If lval == lval_register, this is a further offset from
  58           location.address within the registers structure.
  59        Note also the member embedded_offset below.  */
  60     int offset;
  61     /* Only used for bitfields; number of bits contained in them.  */
  62     int bitsize;
  63     /* Only used for bitfields; position of start of field.
  64        For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  65        For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  66     int bitpos;
  67     /* Frame value is relative to.  In practice, this address is only
  68        used if the value is stored in several registers in other than
  69        the current frame, and these registers have not all been saved
  70        at the same place in memory.  This will be described in the
  71        lval enum above as "lval_reg_frame_relative".  */
  72     CORE_ADDR frame_addr;
  73
  74     /* Type of the value.  */
  75     struct type *type;
  76
  77     /* If a value represents a C++ object, then the `type' field gives
  78        the object's compile-time type.  If the object actually belongs
  79        to some class derived from `type', perhaps with other base
  80        classes and additional members, then `type' is just a subobject
  81        of the real thing, and the full object is probably larger than
  82        `type' would suggest.
  83
  84        If `type' is a dynamic class (i.e. one with a vtable), then GDB
  85        can actually determine the object's run-time type by looking at
  86        the run-time type information in the vtable.  When this
  87        information is available, we may elect to read in the entire
  88        object, for several reasons:
  89
  90          - When printing the value, the user would probably rather see
  91            the full object, not just the limited portion apparent from
  92            the compile-time type.
  93
  94          - If `type' has virtual base classes, then even printing
  95            `type' alone may require reaching outside the `type'
  96            portion of the object to wherever the virtual base class
  97            has been stored.
  98
  99        When we store the entire object, `enclosing_type' is the
 100        run-time type --- the complete object --- and `embedded_offset'
 101        is the offset of `type' within that larger type, in bytes.  The
 102        VALUE_CONTENTS macro takes `embedded_offset' into account, so
 103        most GDB code continues to see the `type' portion of the value,
 104        just as the inferior would.
 105
 106        If `type' is a pointer to an object, then `enclosing_type' is a
 107        pointer to the object's run-time type, and `pointed_to_offset'
 108        is the offset in bytes from the full object to the pointed-to
 109        object --- that is, the value `embedded_offset' would have if
 110        we followed the pointer and fetched the complete object.  (I
 111        don't really see the point.  Why not just determine the
 112        run-time type when you indirect, and avoid the special case?
 113        The contents don't matter until you indirect anyway.)
 114
 115        If we're not doing anything fancy, `enclosing_type' is equal to
 116        `type', and `embedded_offset' is zero, so everything works
 117        normally.  */
 118     struct type *enclosing_type;
 119     int embedded_offset;
 120     int pointed_to_offset;
 121
 122     /* Values are stored in a chain, so that they can be deleted
 123        easily over calls to the inferior.  Values assigned to internal
 124        variables or put into the value history are taken off this
 125        list.  */
 126     struct value *next;
 127
 128     /* Register number if the value is from a register.  Is not kept
 129        if you take a field of a structure that is stored in a
 130        register.  Shouldn't it be?  */
 131     short regno;
 132     /* If zero, contents of this value are in the contents field.
 133        If nonzero, contents are in inferior memory at address
 134        in the location.address field plus the offset field
 135        (and the lval field should be lval_memory).
 136
 137        WARNING: This field is used by the code which handles
 138        watchpoints (see breakpoint.c) to decide whether a particular
 139        value can be watched by hardware watchpoints.  If the lazy flag
 140        is set for some member of a value chain, it is assumed that
 141        this member of the chain doesn't need to be watched as part of
 142        watching the value itself.  This is how GDB avoids watching the
 143        entire struct or array when the user wants to watch a single
 144        struct member or array element.  If you ever change the way
 145        lazy flag is set and reset, be sure to consider this use as
 146        well!  */
 147     char lazy;
 148     /* If nonzero, this is the value of a variable which does not
 149        actually exist in the program.  */
 150     char optimized_out;
 151     /* The BFD section associated with this value.  */
 152     asection *bfd_section;
 153     /* Actual contents of the value.  For use of this value; setting
 154        it uses the stuff above.  Not valid if lazy is nonzero.
 155        Target byte-order.  We force it to be aligned properly for any
 156        possible value.  Note that a value therefore extends beyond
 157        what is declared here.  */
 158     union
 159       {
 160         long contents[1];
 161         DOUBLEST force_doublest_align;
 162         LONGEST force_longest_align;
 163         CORE_ADDR force_core_addr_align;
 164         void *force_pointer_align;
 165       }
 166     aligner;
 167     /* Do not add any new members here -- contents above will trash them */
 168   };
 169
 170 #define VALUE_TYPE(val) (val)->type
 171 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 172 #define VALUE_LAZY(val) (val)->lazy
 173 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 174    the gdb buffer used to hold a copy of the contents of the lval.
 175    VALUE_CONTENTS is used when the contents of the buffer are needed --
 176    it uses value_fetch_lazy() to load the buffer from the process being
 177    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 178    used when data is being stored into the buffer, or when it is
 179    certain that the contents of the buffer are valid.
 180    Note: The contents pointer is adjusted by the offset required to
 181    get to the real subobject, if the value happens to represent
 182    something embedded in a larger run-time object. */
 183
 184 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 185 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 186                              VALUE_CONTENTS_RAW(val))
 187
 188 /* The ALL variants of the above two macros do not adjust the returned
 189    pointer by the embedded_offset value. */
 190
 191 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 192 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 193                                  VALUE_CONTENTS_ALL_RAW(val))
 194
 195
 196 extern int value_fetch_lazy (struct value *val);
 197
 198 #define VALUE_LVAL(val) (val)->lval
 199 #define VALUE_ADDRESS(val) (val)->location.address
 200 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 201 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 202 #define VALUE_FRAME(val) ((val)->frame_addr)
 203 #define VALUE_OFFSET(val) (val)->offset
 204 #define VALUE_BITSIZE(val) (val)->bitsize
 205 #define VALUE_BITPOS(val) (val)->bitpos
 206 #define VALUE_NEXT(val) (val)->next
 207 #define VALUE_REGNO(val) (val)->regno
 208 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 209 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 210 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 211 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 212
 213 /* Convert a REF to the object referenced. */
 214
 215 #define COERCE_REF(arg)    \
 216 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 217      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 218          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 219                               unpack_pointer (VALUE_TYPE (arg),         \
 220                                               VALUE_CONTENTS (arg)),    \
 221                               VALUE_BFD_SECTION (arg));                 \
 222     } while (0)
 223
 224 /* If ARG is an array, convert it to a pointer.
 225    If ARG is an enum, convert it to an integer.
 226    If ARG is a function, convert it to a function pointer.
 227
 228    References are dereferenced.  */
 229
 230 #define COERCE_ARRAY(arg)    \
 231 do { COERCE_REF(arg);                                                   \
 232   if (current_language->c_style_arrays                                  \
 233       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 234     arg = value_coerce_array (arg);                                     \
 235   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 236     arg = value_coerce_function (arg);                                  \
 237 } while (0)
 238
 239 #define COERCE_NUMBER(arg)  \
 240   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 241
 242 #define COERCE_VARYING_ARRAY(arg, real_arg_type)        \
 243 { if (chill_varying_type (real_arg_type))  \
 244     arg = varying_to_slice (arg), real_arg_type = VALUE_TYPE (arg); }
 245
 246 /* If ARG is an enum, convert it to an integer.  */
 247
 248 #define COERCE_ENUM(arg)   { \
 249   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 250     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 251 }
 252
 253 /* Internal variables (variables for convenience of use of debugger)
 254    are recorded as a chain of these structures.  */
 255
 256 struct internalvar
 257   {
 258     struct internalvar *next;
 259     char *name;
 260     struct value *value;
 261   };
 262
 263 /* Pointer to member function.  Depends on compiler implementation. */
 264
 265 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 266 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 267 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 268 \f
 269
 270 #include "symtab.h"
 271 #include "gdbtypes.h"
 272 #include "expression.h"
 273
 274 struct frame_info;
 275 struct fn_field;
 276
 277 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 278
 279 extern LONGEST value_as_long (struct value *val);
 280
 281 extern DOUBLEST value_as_double (struct value *val);
 282
 283 extern CORE_ADDR value_as_address (struct value *val);
 284
 285 extern LONGEST unpack_long (struct type *type, char *valaddr);
 286
 287 extern DOUBLEST unpack_double (struct type *type, char *valaddr, int *invp);
 288
 289 extern CORE_ADDR unpack_pointer (struct type *type, char *valaddr);
 290
 291 extern LONGEST unpack_field_as_long (struct type *type, char *valaddr,
 292                                      int fieldno);
 293
 294 extern struct value *value_from_longest (struct type *type, LONGEST num);
 295
 296 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 297
 298 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 299
 300 extern struct value *value_from_string (char *string);
 301
 302 extern struct value *value_at (struct type *type, CORE_ADDR addr,
 303                                asection * sect);
 304
 305 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
 306                                     asection * sect);
 307
 308 extern struct value *value_from_register (struct type *type, int regnum,
 309                                           struct frame_info *frame);
 310
 311 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 312
 313 extern struct value *value_of_register (int regnum,
 314                                         struct frame_info *frame);
 315
 316 extern int symbol_read_needs_frame (struct symbol *);
 317
 318 extern struct value *read_var_value (struct symbol *var,
 319                                      struct frame_info *frame);
 320
 321 extern struct value *locate_var_value (struct symbol *var,
 322                                        struct frame_info *frame);
 323
 324 extern struct value *allocate_value (struct type *type);
 325
 326 extern struct value *allocate_repeat_value (struct type *type, int count);
 327
 328 extern struct value *value_change_enclosing_type (struct value *val,
 329                                                   struct type *new_type);
 330
 331 extern struct value *value_mark (void);
 332
 333 extern void value_free_to_mark (struct value *mark);
 334
 335 extern struct value *value_string (char *ptr, int len);
 336 extern struct value *value_bitstring (char *ptr, int len);
 337
 338 extern struct value *value_array (int lowbound, int highbound,
 339                                   struct value ** elemvec);
 340
 341 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 342
 343 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 344                                   enum exp_opcode op);
 345
 346 extern struct value *value_add (struct value *arg1, struct value *arg2);
 347
 348 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 349
 350 extern struct value *value_coerce_array (struct value *arg1);
 351
 352 extern struct value *value_coerce_function (struct value *arg1);
 353
 354 extern struct value *value_ind (struct value *arg1);
 355
 356 extern struct value *value_addr (struct value *arg1);
 357
 358 extern struct value *value_assign (struct value *toval, struct value *fromval);
 359
 360 extern struct value *value_neg (struct value *arg1);
 361
 362 extern struct value *value_complement (struct value *arg1);
 363
 364 extern struct value *value_struct_elt (struct value **argp,
 365                                        struct value **args,
 366                                        char *name, int *static_memfuncp,
 367                                        char *err);
 368
 369 extern struct value *value_struct_elt_for_reference (struct type *domain,
 370                                                      int offset,
 371                                                      struct type *curtype,
 372                                                      char *name,
 373                                                      struct type *intype);
 374
 375 extern struct value *value_static_field (struct type *type, int fieldno);
 376
 377 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 378                                                       int, int *, int *,
 379                                                       struct type **, int *);
 380
 381 extern int find_overload_match (struct type **arg_types, int nargs,
 382                                 char *name, int method, int lax,
 383                                 struct value **objp, struct symbol *fsym,
 384                                 struct value **valp, struct symbol **symp,
 385                                 int *staticp);
 386
 387 extern struct value *value_field (struct value *arg1, int fieldno);
 388
 389 extern struct value *value_primitive_field (struct value *arg1, int offset,
 390                                             int fieldno,
 391                                             struct type *arg_type);
 392
 393
 394 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 395                                             int *);
 396
 397 extern struct value *value_full_object (struct value *, struct type *, int,
 398                                         int, int);
 399
 400 extern struct value *value_cast (struct type *type, struct value *arg2);
 401
 402 extern struct value *value_zero (struct type *type, enum lval_type lv);
 403
 404 extern struct value *value_repeat (struct value *arg1, int count);
 405
 406 extern struct value *value_subscript (struct value *array, struct value *idx);
 407
 408 extern struct value *value_from_vtable_info (struct value *arg,
 409                                              struct type *type);
 410
 411 extern struct value *value_being_returned (struct type *valtype,
 412                                            char *retbuf, 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 int default_coerce_float_to_double (struct type *, struct type *);
 552
 553 extern int standard_coerce_float_to_double (struct type *, struct type *);
 554
 555 extern struct value *value_literal_complex (struct value *, struct value *,
 556                                             struct type *);
 557
 558 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 559                                   int *, int *);
 560
 561 extern struct value *find_function_in_inferior (char *);
 562
 563 extern struct value *value_allocate_space_in_inferior (int);
 564
 565 extern CORE_ADDR default_push_arguments (int nargs, struct value ** args,
 566                                          CORE_ADDR sp, int struct_return,
 567                                          CORE_ADDR struct_addr);
 568
 569 #endif /* !defined (VALUE_H) */