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 ui_file;
  27 struct expression;
  28 struct symbol;
  29 struct type;
  30 struct regcache;
  31 struct block;
  32
  33 #include "doublest.h"
  34
  35 /*
  36  * The structure which defines the type of a value.  It should never
  37  * be possible for a program lval value to survive over a call to the inferior
  38  * (ie to be put into the history list or an internal variable).
  39  */
  40
  41 struct value
  42   {
  43     /* Type of value; either not an lval, or one of the various
  44        different possible kinds of lval.  */
  45     enum lval_type lval;
  46     /* Is it modifiable?  Only relevant if lval != not_lval.  */
  47     int modifiable;
  48     /* Location of value (if lval).  */
  49     union
  50       {
  51         /* If lval == lval_memory, this is the address in the inferior.
  52            If lval == lval_register, this is the byte offset into the
  53            registers structure.  */
  54         CORE_ADDR address;
  55         /* Pointer to internal variable.  */
  56         struct internalvar *internalvar;
  57         /* Number of register.  Only used with
  58            lval_reg_frame_relative.  */
  59         int regnum;
  60       }
  61     location;
  62     /* Describes offset of a value within lval of a structure in bytes.
  63        If lval == lval_memory, this is an offset to the address.
  64        If lval == lval_register, this is a further offset from
  65           location.address within the registers structure.
  66        Note also the member embedded_offset below.  */
  67     int offset;
  68     /* Only used for bitfields; number of bits contained in them.  */
  69     int bitsize;
  70     /* Only used for bitfields; position of start of field.
  71        For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  72        For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  73     int bitpos;
  74     /* Frame value is relative to.  In practice, this address is only
  75        used if the value is stored in several registers in other than
  76        the current frame, and these registers have not all been saved
  77        at the same place in memory.  This will be described in the
  78        lval enum above as "lval_reg_frame_relative".  */
  79     CORE_ADDR frame_addr;
  80
  81     /* Type of the value.  */
  82     struct type *type;
  83
  84     /* If a value represents a C++ object, then the `type' field gives
  85        the object's compile-time type.  If the object actually belongs
  86        to some class derived from `type', perhaps with other base
  87        classes and additional members, then `type' is just a subobject
  88        of the real thing, and the full object is probably larger than
  89        `type' would suggest.
  90
  91        If `type' is a dynamic class (i.e. one with a vtable), then GDB
  92        can actually determine the object's run-time type by looking at
  93        the run-time type information in the vtable.  When this
  94        information is available, we may elect to read in the entire
  95        object, for several reasons:
  96
  97          - When printing the value, the user would probably rather see
  98            the full object, not just the limited portion apparent from
  99            the compile-time type.
 100
 101          - If `type' has virtual base classes, then even printing
 102            `type' alone may require reaching outside the `type'
 103            portion of the object to wherever the virtual base class
 104            has been stored.
 105
 106        When we store the entire object, `enclosing_type' is the
 107        run-time type --- the complete object --- and `embedded_offset'
 108        is the 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'
 115        is the offset in bytes from the full object to the pointed-to
 116        object --- that is, the value `embedded_offset' would have if
 117        we followed the pointer and fetched the complete object.  (I
 118        don't really see the point.  Why not just determine the
 119        run-time type when you indirect, and avoid the special case?
 120        The contents 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 regno;
 137     /* If zero, contents of this value are in the contents field.
 138        If nonzero, contents are in inferior memory at address
 139        in the location.address field plus the offset field
 140        (and the lval field should be lval_memory).
 141
 142        WARNING: This field is used by the code which handles
 143        watchpoints (see breakpoint.c) to decide whether a particular
 144        value can be watched by hardware watchpoints.  If the lazy flag
 145        is set for some member of a value chain, it is assumed that
 146        this member of the chain doesn't need to be watched as part of
 147        watching the value itself.  This is how GDB avoids watching the
 148        entire struct or array when the user wants to watch a single
 149        struct member or array element.  If you ever change the way
 150        lazy flag is set and reset, be sure to consider this use as
 151        well!  */
 152     char lazy;
 153     /* If nonzero, this is the value of a variable which does not
 154        actually exist in the program.  */
 155     char optimized_out;
 156     /* The BFD section associated with this value.  */
 157     asection *bfd_section;
 158     /* Actual contents of the value.  For use of this value; setting
 159        it uses the stuff above.  Not valid if lazy is nonzero.
 160        Target byte-order.  We force it to be aligned properly for any
 161        possible value.  Note that a value therefore extends beyond
 162        what is declared here.  */
 163     union
 164       {
 165         long contents[1];
 166         DOUBLEST force_doublest_align;
 167         LONGEST force_longest_align;
 168         CORE_ADDR force_core_addr_align;
 169         void *force_pointer_align;
 170       }
 171     aligner;
 172     /* Do not add any new members here -- contents above will trash them */
 173   };
 174
 175 #define VALUE_TYPE(val) (val)->type
 176 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 177 #define VALUE_LAZY(val) (val)->lazy
 178 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 179    the gdb buffer used to hold a copy of the contents of the lval.
 180    VALUE_CONTENTS is used when the contents of the buffer are needed --
 181    it uses value_fetch_lazy() to load the buffer from the process being
 182    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 183    used when data is being stored into the buffer, or when it is
 184    certain that the contents of the buffer are valid.
 185    Note: The contents pointer is adjusted by the offset required to
 186    get to the real subobject, if the value happens to represent
 187    something embedded in a larger run-time object. */
 188
 189 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 190 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 191                              VALUE_CONTENTS_RAW(val))
 192
 193 /* The ALL variants of the above two macros do not adjust the returned
 194    pointer by the embedded_offset value. */
 195
 196 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 197 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 198                                  VALUE_CONTENTS_ALL_RAW(val))
 199
 200
 201 extern int value_fetch_lazy (struct value *val);
 202
 203 #define VALUE_LVAL(val) (val)->lval
 204 #define VALUE_ADDRESS(val) (val)->location.address
 205 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 206 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 207 #define VALUE_FRAME(val) ((val)->frame_addr)
 208 #define VALUE_OFFSET(val) (val)->offset
 209 #define VALUE_BITSIZE(val) (val)->bitsize
 210 #define VALUE_BITPOS(val) (val)->bitpos
 211 #define VALUE_NEXT(val) (val)->next
 212 #define VALUE_REGNO(val) (val)->regno
 213 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 214 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 215 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 216 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 217
 218 /* Convert a REF to the object referenced. */
 219
 220 #define COERCE_REF(arg)    \
 221 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 222      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 223          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 224                               unpack_pointer (VALUE_TYPE (arg),         \
 225                                               VALUE_CONTENTS (arg)),    \
 226                               VALUE_BFD_SECTION (arg));                 \
 227     } while (0)
 228
 229 /* If ARG is an array, convert it to a pointer.
 230    If ARG is an enum, convert it to an integer.
 231    If ARG is a function, convert it to a function pointer.
 232
 233    References are dereferenced.  */
 234
 235 #define COERCE_ARRAY(arg)    \
 236 do { COERCE_REF(arg);                                                   \
 237   if (current_language->c_style_arrays                                  \
 238       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 239     arg = value_coerce_array (arg);                                     \
 240   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 241     arg = value_coerce_function (arg);                                  \
 242 } while (0)
 243
 244 #define COERCE_NUMBER(arg)  \
 245   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 246
 247 /* NOTE: cagney/2002-12-17: This macro was handling a chill language
 248    problem but that language has gone away.  */
 249 #define COERCE_VARYING_ARRAY(arg, real_arg_type)
 250
 251 /* If ARG is an enum, convert it to an integer.  */
 252
 253 #define COERCE_ENUM(arg)   { \
 254   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 255     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 256 }
 257
 258 /* Internal variables (variables for convenience of use of debugger)
 259    are recorded as a chain of these structures.  */
 260
 261 struct internalvar
 262   {
 263     struct internalvar *next;
 264     char *name;
 265     struct value *value;
 266   };
 267
 268 /* Pointer to member function.  Depends on compiler implementation. */
 269
 270 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 271 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 272 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 273 \f
 274
 275 #include "symtab.h"
 276 #include "gdbtypes.h"
 277 #include "expression.h"
 278
 279 struct frame_info;
 280 struct fn_field;
 281
 282 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 283
 284 extern LONGEST value_as_long (struct value *val);
 285
 286 extern DOUBLEST value_as_double (struct value *val);
 287
 288 extern CORE_ADDR value_as_address (struct value *val);
 289
 290 extern LONGEST unpack_long (struct type *type, const char *valaddr);
 291
 292 extern DOUBLEST unpack_double (struct type *type, const char *valaddr,
 293                                int *invp);
 294
 295 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr);
 296
 297 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr,
 298                                      int fieldno);
 299
 300 extern struct value *value_from_longest (struct type *type, LONGEST num);
 301
 302 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 303
 304 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 305
 306 extern struct value *value_from_string (char *string);
 307
 308 extern struct value *value_at (struct type *type, CORE_ADDR addr,
 309                                asection * sect);
 310
 311 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
 312                                     asection * sect);
 313
 314 extern struct value *value_from_register (struct type *type, int regnum,
 315                                           struct frame_info *frame);
 316
 317 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 318
 319 extern struct value *value_of_register (int regnum,
 320                                         struct frame_info *frame);
 321
 322 extern int symbol_read_needs_frame (struct symbol *);
 323
 324 extern struct value *read_var_value (struct symbol *var,
 325                                      struct frame_info *frame);
 326
 327 extern struct value *locate_var_value (struct symbol *var,
 328                                        struct frame_info *frame);
 329
 330 extern struct value *allocate_value (struct type *type);
 331
 332 extern struct value *allocate_repeat_value (struct type *type, int count);
 333
 334 extern struct value *value_change_enclosing_type (struct value *val,
 335                                                   struct type *new_type);
 336
 337 extern struct value *value_mark (void);
 338
 339 extern void value_free_to_mark (struct value *mark);
 340
 341 extern struct value *value_string (char *ptr, int len);
 342 extern struct value *value_bitstring (char *ptr, int len);
 343
 344 extern struct value *value_array (int lowbound, int highbound,
 345                                   struct value ** elemvec);
 346
 347 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 348
 349 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 350                                   enum exp_opcode op);
 351
 352 extern struct value *value_add (struct value *arg1, struct value *arg2);
 353
 354 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 355
 356 extern struct value *value_coerce_array (struct value *arg1);
 357
 358 extern struct value *value_coerce_function (struct value *arg1);
 359
 360 extern struct value *value_ind (struct value *arg1);
 361
 362 extern struct value *value_addr (struct value *arg1);
 363
 364 extern struct value *value_assign (struct value *toval, struct value *fromval);
 365
 366 extern struct value *value_neg (struct value *arg1);
 367
 368 extern struct value *value_complement (struct value *arg1);
 369
 370 extern struct value *value_struct_elt (struct value **argp,
 371                                        struct value **args,
 372                                        char *name, int *static_memfuncp,
 373                                        char *err);
 374
 375 extern struct value *value_struct_elt_for_reference (struct type *domain,
 376                                                      int offset,
 377                                                      struct type *curtype,
 378                                                      char *name,
 379                                                      struct type *intype);
 380
 381 extern struct value *value_static_field (struct type *type, int fieldno);
 382
 383 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 384                                                       int, int *,
 385                                                       struct type **, int *);
 386
 387 extern int find_overload_match (struct type **arg_types, int nargs,
 388                                 char *name, int method, int lax,
 389                                 struct value **objp, struct symbol *fsym,
 390                                 struct value **valp, struct symbol **symp,
 391                                 int *staticp);
 392
 393 extern struct value *value_field (struct value *arg1, int fieldno);
 394
 395 extern struct value *value_primitive_field (struct value *arg1, int offset,
 396                                             int fieldno,
 397                                             struct type *arg_type);
 398
 399
 400 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 401                                             int *);
 402
 403 extern struct value *value_full_object (struct value *, struct type *, int,
 404                                         int, int);
 405
 406 extern struct value *value_cast (struct type *type, struct value *arg2);
 407
 408 extern struct value *value_zero (struct type *type, enum lval_type lv);
 409
 410 extern struct value *value_repeat (struct value *arg1, int count);
 411
 412 extern struct value *value_subscript (struct value *array, struct value *idx);
 413
 414 extern struct value *value_being_returned (struct type *valtype,
 415                                            struct regcache *retbuf,
 416                                            int struct_return);
 417
 418 extern struct value *value_in (struct value *element, struct value *set);
 419
 420 extern int value_bit_index (struct type *type, char *addr, int index);
 421
 422 extern int using_struct_return (struct value *function, CORE_ADDR funcaddr,
 423                                 struct type *value_type, int gcc_p);
 424
 425 extern void set_return_value (struct value *val);
 426
 427 extern struct value *evaluate_expression (struct expression *exp);
 428
 429 extern struct value *evaluate_type (struct expression *exp);
 430
 431 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 432                                                     int *, enum noside);
 433
 434 extern struct value *parse_and_eval (char *exp);
 435
 436 extern struct value *parse_to_comma_and_eval (char **expp);
 437
 438 extern struct type *parse_and_eval_type (char *p, int length);
 439
 440 extern CORE_ADDR parse_and_eval_address (char *exp);
 441
 442 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 443
 444 extern LONGEST parse_and_eval_long (char *exp);
 445
 446 extern struct value *access_value_history (int num);
 447
 448 extern struct value *value_of_internalvar (struct internalvar *var);
 449
 450 extern void set_internalvar (struct internalvar *var, struct value *val);
 451
 452 extern void set_internalvar_component (struct internalvar *var,
 453                                        int offset,
 454                                        int bitpos, int bitsize,
 455                                        struct value *newvalue);
 456
 457 extern struct internalvar *lookup_internalvar (char *name);
 458
 459 extern int value_equal (struct value *arg1, struct value *arg2);
 460
 461 extern int value_less (struct value *arg1, struct value *arg2);
 462
 463 extern int value_logical_not (struct value *arg1);
 464
 465 /* C++ */
 466
 467 extern struct value *value_of_this (int complain);
 468
 469 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 470                                     enum exp_opcode op,
 471                                     enum exp_opcode otherop,
 472                                     enum noside noside);
 473
 474 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 475                                    enum noside noside);
 476
 477 extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
 478                                      int j, struct type *type, int offset);
 479
 480 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 481                                  struct value *arg2);
 482
 483 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 484
 485 extern int destructor_name_p (const char *name, const struct type *type);
 486
 487 #define value_free(val) xfree (val)
 488
 489 extern void free_all_values (void);
 490
 491 extern void release_value (struct value *val);
 492
 493 extern int record_latest_value (struct value *val);
 494
 495 extern void modify_field (char *addr, LONGEST fieldval, int bitpos,
 496                           int bitsize);
 497
 498 extern void type_print (struct type * type, char *varstring,
 499                         struct ui_file * stream, int show);
 500
 501 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 502                              struct value **valuep, int *errp);
 503
 504 extern void print_longest (struct ui_file * stream, int format,
 505                            int use_local, LONGEST val);
 506
 507 extern void print_floating (char *valaddr, struct type * type,
 508                             struct ui_file * stream);
 509
 510 extern int value_print (struct value *val, struct ui_file *stream, int format,
 511                         enum val_prettyprint pretty);
 512
 513 extern void value_print_array_elements (struct value *val,
 514                                         struct ui_file *stream, int format,
 515                                         enum val_prettyprint pretty);
 516
 517 extern struct value *value_release_to_mark (struct value *mark);
 518
 519 extern int val_print (struct type * type, char *valaddr,
 520                       int embedded_offset, CORE_ADDR address,
 521                       struct ui_file * stream, int format,
 522                       int deref_ref, int recurse,
 523                       enum val_prettyprint pretty);
 524
 525 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 526
 527 extern void print_variable_value (struct symbol * var,
 528                                   struct frame_info * frame,
 529                                   struct ui_file *stream);
 530
 531 extern int check_field (struct value *, const char *);
 532
 533 extern void typedef_print (struct type * type, struct symbol * news,
 534                              struct ui_file * stream);
 535
 536 extern char *internalvar_name (struct internalvar *var);
 537
 538 extern void clear_value_history (void);
 539
 540 extern void clear_internalvars (void);
 541
 542 /* From values.c */
 543
 544 extern struct value *value_copy (struct value *);
 545
 546 /* From valops.c */
 547
 548 extern struct value *varying_to_slice (struct value *);
 549
 550 extern struct value *value_slice (struct value *, int, int);
 551
 552 extern struct value *call_function_by_hand (struct value *, int,
 553                                             struct value **);
 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 (const char *);
 562
 563 extern struct value *value_allocate_space_in_inferior (int);
 564
 565 extern CORE_ADDR legacy_push_arguments (int nargs, struct value ** args,
 566                                         CORE_ADDR sp, int struct_return,
 567                                         CORE_ADDR struct_addr);
 568
 569 extern struct value *value_of_local (const char *name, int complain);
 570
 571 #endif /* !defined (VALUE_H) */