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