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     /* ??? When is this used?  */
 129     union
 130       {
 131         CORE_ADDR memaddr;
 132         char *myaddr;
 133       }
 134     substring_addr;
 135
 136     /* Register number if the value is from a register.  Is not kept
 137        if you take a field of a structure that is stored in a
 138        register.  Shouldn't it be?  */
 139     short regno;
 140     /* If zero, contents of this value are in the contents field.
 141        If nonzero, contents are in inferior memory at address
 142        in the location.address field plus the offset field
 143        (and the lval field should be lval_memory).
 144
 145        WARNING: This field is used by the code which handles
 146        watchpoints (see breakpoint.c) to decide whether a particular
 147        value can be watched by hardware watchpoints.  If the lazy flag
 148        is set for some member of a value chain, it is assumed that
 149        this member of the chain doesn't need to be watched as part of
 150        watching the value itself.  This is how GDB avoids watching the
 151        entire struct or array when the user wants to watch a single
 152        struct member or array element.  If you ever change the way
 153        lazy flag is set and reset, be sure to consider this use as
 154        well!  */
 155     char lazy;
 156     /* If nonzero, this is the value of a variable which does not
 157        actually exist in the program.  */
 158     char optimized_out;
 159     /* The BFD section associated with this value.  */
 160     asection *bfd_section;
 161     /* Actual contents of the value.  For use of this value; setting
 162        it uses the stuff above.  Not valid if lazy is nonzero.
 163        Target byte-order.  We force it to be aligned properly for any
 164        possible value.  Note that a value therefore extends beyond
 165        what is declared here.  */
 166     union
 167       {
 168         long contents[1];
 169         double force_double_align;
 170         LONGEST force_longlong_align;
 171         char *literal_data;
 172       }
 173     aligner;
 174     /* Do not add any new members here -- contents above will trash them */
 175   };
 176
 177 #define VALUE_TYPE(val) (val)->type
 178 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 179 #define VALUE_LAZY(val) (val)->lazy
 180 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 181    the gdb buffer used to hold a copy of the contents of the lval.
 182    VALUE_CONTENTS is used when the contents of the buffer are needed --
 183    it uses value_fetch_lazy() to load the buffer from the process being
 184    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 185    used when data is being stored into the buffer, or when it is
 186    certain that the contents of the buffer are valid.
 187    Note: The contents pointer is adjusted by the offset required to
 188    get to the real subobject, if the value happens to represent
 189    something embedded in a larger run-time object. */
 190
 191 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 192 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 193                              VALUE_CONTENTS_RAW(val))
 194
 195 /* The ALL variants of the above two macros do not adjust the returned
 196    pointer by the embedded_offset value. */
 197
 198 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 199 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 200                                  VALUE_CONTENTS_ALL_RAW(val))
 201
 202
 203 extern int value_fetch_lazy (struct value *val);
 204
 205 #define VALUE_LVAL(val) (val)->lval
 206 #define VALUE_ADDRESS(val) (val)->location.address
 207 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 208 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 209 #define VALUE_FRAME(val) ((val)->frame_addr)
 210 #define VALUE_OFFSET(val) (val)->offset
 211 #define VALUE_BITSIZE(val) (val)->bitsize
 212 #define VALUE_BITPOS(val) (val)->bitpos
 213 #define VALUE_NEXT(val) (val)->next
 214 #define VALUE_REGNO(val) (val)->regno
 215 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 216 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 217 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 218 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 219
 220 /* Convert a REF to the object referenced. */
 221
 222 #define COERCE_REF(arg)    \
 223 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 224      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 225          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 226                               unpack_pointer (VALUE_TYPE (arg),         \
 227                                               VALUE_CONTENTS (arg)),    \
 228                               VALUE_BFD_SECTION (arg));                 \
 229     } while (0)
 230
 231 /* If ARG is an array, convert it to a pointer.
 232    If ARG is an enum, convert it to an integer.
 233    If ARG is a function, convert it to a function pointer.
 234
 235    References are dereferenced.  */
 236
 237 #define COERCE_ARRAY(arg)    \
 238 do { COERCE_REF(arg);                                                   \
 239   if (current_language->c_style_arrays                                  \
 240       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 241     arg = value_coerce_array (arg);                                     \
 242   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 243     arg = value_coerce_function (arg);                                  \
 244 } while (0)
 245
 246 #define COERCE_NUMBER(arg)  \
 247   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 248
 249 #define COERCE_VARYING_ARRAY(arg, real_arg_type)        \
 250 { if (chill_varying_type (real_arg_type))  \
 251     arg = varying_to_slice (arg), real_arg_type = VALUE_TYPE (arg); }
 252
 253 /* If ARG is an enum, convert it to an integer.  */
 254
 255 #define COERCE_ENUM(arg)   { \
 256   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 257     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 258 }
 259
 260 /* Internal variables (variables for convenience of use of debugger)
 261    are recorded as a chain of these structures.  */
 262
 263 struct internalvar
 264   {
 265     struct internalvar *next;
 266     char *name;
 267     struct value *value;
 268   };
 269
 270 /* Pointer to member function.  Depends on compiler implementation. */
 271
 272 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 273 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 274 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 275 \f
 276
 277 #include "symtab.h"
 278 #include "gdbtypes.h"
 279 #include "expression.h"
 280
 281 struct frame_info;
 282 struct fn_field;
 283
 284 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 285
 286 extern LONGEST value_as_long (struct value *val);
 287
 288 extern DOUBLEST value_as_double (struct value *val);
 289
 290 extern CORE_ADDR value_as_address (struct value *val);
 291
 292 extern LONGEST unpack_long (struct type *type, char *valaddr);
 293
 294 extern DOUBLEST unpack_double (struct type *type, char *valaddr, int *invp);
 295
 296 extern CORE_ADDR unpack_pointer (struct type *type, char *valaddr);
 297
 298 extern LONGEST unpack_field_as_long (struct type *type, char *valaddr,
 299                                      int fieldno);
 300
 301 extern struct value *value_from_longest (struct type *type, LONGEST num);
 302
 303 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr);
 304
 305 extern struct value *value_from_double (struct type *type, DOUBLEST num);
 306
 307 extern struct value *value_from_string (char *string);
 308
 309 extern struct value *value_at (struct type *type, CORE_ADDR addr,
 310                                asection * sect);
 311
 312 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr,
 313                                     asection * sect);
 314
 315 extern struct value *value_from_register (struct type *type, int regnum,
 316                                           struct frame_info *frame);
 317
 318 extern struct value *value_of_variable (struct symbol *var, struct block *b);
 319
 320 extern struct value *value_of_register (int regnum,
 321                                         struct frame_info *frame);
 322
 323 extern int symbol_read_needs_frame (struct symbol *);
 324
 325 extern struct value *read_var_value (struct symbol *var,
 326                                      struct frame_info *frame);
 327
 328 extern struct value *locate_var_value (struct symbol *var,
 329                                        struct frame_info *frame);
 330
 331 extern struct value *allocate_value (struct type *type);
 332
 333 extern struct value *allocate_repeat_value (struct type *type, int count);
 334
 335 extern struct value *value_change_enclosing_type (struct value *val,
 336                                                   struct type *new_type);
 337
 338 extern struct value *value_mark (void);
 339
 340 extern void value_free_to_mark (struct value *mark);
 341
 342 extern struct value *value_string (char *ptr, int len);
 343 extern struct value *value_bitstring (char *ptr, int len);
 344
 345 extern struct value *value_array (int lowbound, int highbound,
 346                                   struct value ** elemvec);
 347
 348 extern struct value *value_concat (struct value *arg1, struct value *arg2);
 349
 350 extern struct value *value_binop (struct value *arg1, struct value *arg2,
 351                                   enum exp_opcode op);
 352
 353 extern struct value *value_add (struct value *arg1, struct value *arg2);
 354
 355 extern struct value *value_sub (struct value *arg1, struct value *arg2);
 356
 357 extern struct value *value_coerce_array (struct value *arg1);
 358
 359 extern struct value *value_coerce_function (struct value *arg1);
 360
 361 extern struct value *value_ind (struct value *arg1);
 362
 363 extern struct value *value_addr (struct value *arg1);
 364
 365 extern struct value *value_assign (struct value *toval, struct value *fromval);
 366
 367 extern struct value *value_neg (struct value *arg1);
 368
 369 extern struct value *value_complement (struct value *arg1);
 370
 371 extern struct value *value_struct_elt (struct value **argp,
 372                                        struct value **args,
 373                                        char *name, int *static_memfuncp,
 374                                        char *err);
 375
 376 extern struct value *value_struct_elt_for_reference (struct type *domain,
 377                                                      int offset,
 378                                                      struct type *curtype,
 379                                                      char *name,
 380                                                      struct type *intype);
 381
 382 extern struct value *value_static_field (struct type *type, int fieldno);
 383
 384 extern struct fn_field *value_find_oload_method_list (struct value **, char *,
 385                                                       int, int *, int *,
 386                                                       struct type **, int *);
 387
 388 extern int find_overload_match (struct type **arg_types, int nargs,
 389                                 char *name, int method, int lax,
 390                                 struct value **objp, struct symbol *fsym,
 391                                 struct value **valp, struct symbol **symp,
 392                                 int *staticp);
 393
 394 extern struct value *value_field (struct value *arg1, int fieldno);
 395
 396 extern struct value *value_primitive_field (struct value *arg1, int offset,
 397                                             int fieldno,
 398                                             struct type *arg_type);
 399
 400
 401 extern struct type *value_rtti_target_type (struct value *, int *, int *,
 402                                             int *);
 403
 404 extern struct value *value_full_object (struct value *, struct type *, int,
 405                                         int, int);
 406
 407 extern struct value *value_cast (struct type *type, struct value *arg2);
 408
 409 extern struct value *value_zero (struct type *type, enum lval_type lv);
 410
 411 extern struct value *value_repeat (struct value *arg1, int count);
 412
 413 extern struct value *value_subscript (struct value *array, struct value *idx);
 414
 415 extern struct value *value_from_vtable_info (struct value *arg,
 416                                              struct type *type);
 417
 418 extern struct value *value_being_returned (struct type *valtype,
 419                                            char *retbuf, int struct_return);
 420
 421 extern struct value *value_in (struct value *element, struct value *set);
 422
 423 extern int value_bit_index (struct type *type, char *addr, int index);
 424
 425 extern int using_struct_return (struct value *function, CORE_ADDR funcaddr,
 426                                 struct type *value_type, int gcc_p);
 427
 428 extern void set_return_value (struct value *val);
 429
 430 extern struct value *evaluate_expression (struct expression *exp);
 431
 432 extern struct value *evaluate_type (struct expression *exp);
 433
 434 extern struct value *evaluate_subexp_with_coercion (struct expression *,
 435                                                     int *, enum noside);
 436
 437 extern struct value *parse_and_eval (char *exp);
 438
 439 extern struct value *parse_to_comma_and_eval (char **expp);
 440
 441 extern struct type *parse_and_eval_type (char *p, int length);
 442
 443 extern CORE_ADDR parse_and_eval_address (char *exp);
 444
 445 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 446
 447 extern LONGEST parse_and_eval_long (char *exp);
 448
 449 extern struct value *access_value_history (int num);
 450
 451 extern struct value *value_of_internalvar (struct internalvar *var);
 452
 453 extern void set_internalvar (struct internalvar *var, struct value *val);
 454
 455 extern void set_internalvar_component (struct internalvar *var,
 456                                        int offset,
 457                                        int bitpos, int bitsize,
 458                                        struct value *newvalue);
 459
 460 extern struct internalvar *lookup_internalvar (char *name);
 461
 462 extern int value_equal (struct value *arg1, struct value *arg2);
 463
 464 extern int value_less (struct value *arg1, struct value *arg2);
 465
 466 extern int value_logical_not (struct value *arg1);
 467
 468 /* C++ */
 469
 470 extern struct value *value_of_this (int complain);
 471
 472 extern struct value *value_x_binop (struct value *arg1, struct value *arg2,
 473                                     enum exp_opcode op,
 474                                     enum exp_opcode otherop,
 475                                     enum noside noside);
 476
 477 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op,
 478                                    enum noside noside);
 479
 480 extern struct value *value_fn_field (struct value ** arg1p, struct fn_field *f,
 481                                      int j, struct type *type, int offset);
 482
 483 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1,
 484                                  struct value *arg2);
 485
 486 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1);
 487
 488 extern int destructor_name_p (const char *name, const struct type *type);
 489
 490 #define value_free(val) xfree (val)
 491
 492 extern void free_all_values (void);
 493
 494 extern void release_value (struct value *val);
 495
 496 extern int record_latest_value (struct value *val);
 497
 498 extern void
 499 modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize);
 500
 501 extern void type_print (struct type * type, char *varstring,
 502                         struct ui_file * stream, int show);
 503
 504 extern char *baseclass_addr (struct type *type, int index, char *valaddr,
 505                              struct value **valuep, int *errp);
 506
 507 extern void print_longest (struct ui_file * stream, int format,
 508                            int use_local, LONGEST val);
 509
 510 extern void print_floating (char *valaddr, struct type * type,
 511                             struct ui_file * stream);
 512
 513 extern int value_print (struct value *val, struct ui_file *stream, int format,
 514                         enum val_prettyprint pretty);
 515
 516 extern void value_print_array_elements (struct value *val,
 517                                         struct ui_file *stream, int format,
 518                                         enum val_prettyprint pretty);
 519
 520 extern struct value *value_release_to_mark (struct value *mark);
 521
 522 extern int val_print (struct type * type, char *valaddr,
 523                       int embedded_offset, CORE_ADDR address,
 524                       struct ui_file * stream, int format,
 525                       int deref_ref, int recurse,
 526                       enum val_prettyprint pretty);
 527
 528 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 529
 530 extern void print_variable_value (struct symbol * var,
 531                                   struct frame_info * frame,
 532                                   struct ui_file *stream);
 533
 534 extern int check_field (struct value *, const char *);
 535
 536 extern void typedef_print (struct type * type, struct symbol * news,
 537                              struct ui_file * stream);
 538
 539 extern char *internalvar_name (struct internalvar *var);
 540
 541 extern void clear_value_history (void);
 542
 543 extern void clear_internalvars (void);
 544
 545 /* From values.c */
 546
 547 extern struct value *value_copy (struct value *);
 548
 549 /* From valops.c */
 550
 551 extern struct value *varying_to_slice (struct value *);
 552
 553 extern struct value *value_slice (struct value *, int, int);
 554
 555 extern struct value *call_function_by_hand (struct value *, int,
 556                                             struct value **);
 557
 558 extern int default_coerce_float_to_double (struct type *, struct type *);
 559
 560 extern int standard_coerce_float_to_double (struct type *, struct type *);
 561
 562 extern struct value *value_literal_complex (struct value *, struct value *,
 563                                             struct type *);
 564
 565 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 566                                   int *, int *);
 567
 568 extern struct value *find_function_in_inferior (char *);
 569
 570 extern struct value *value_allocate_space_in_inferior (int);
 571
 572 extern CORE_ADDR default_push_arguments (int nargs, struct value ** args,
 573                                          CORE_ADDR sp, int struct_return,
 574                                          CORE_ADDR struct_addr);
 575
 576 #endif /* !defined (VALUE_H) */