gdb/value.h

   1 /* Definitions for values of C expressions, for GDB.
   2    Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995,
   3    1996, 1997, 1998, 1999, 2000, 2001
   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 /*
  27  * The structure which defines the type of a value.  It should never
  28  * be possible for a program lval value to survive over a call to the inferior
  29  * (ie to be put into the history list or an internal variable).
  30  */
  31
  32 struct value
  33   {
  34     /* Type of value; either not an lval, or one of the various
  35        different possible kinds of lval.  */
  36     enum lval_type lval;
  37     /* Is it modifiable?  Only relevant if lval != not_lval.  */
  38     int modifiable;
  39     /* Location of value (if lval).  */
  40     union
  41       {
  42         /* If lval == lval_memory, this is the address in the inferior.
  43            If lval == lval_register, this is the byte offset into the
  44            registers structure.  */
  45         CORE_ADDR address;
  46         /* Pointer to internal variable.  */
  47         struct internalvar *internalvar;
  48         /* Number of register.  Only used with
  49            lval_reg_frame_relative.  */
  50         int regnum;
  51       }
  52     location;
  53     /* Describes offset of a value within lval of a structure in bytes.
  54        If lval == lval_memory, this is an offset to the address.
  55        If lval == lval_register, this is a further offset from
  56           location.address within the registers structure.
  57        Note also the member embedded_offset below.  */
  58     int offset;
  59     /* Only used for bitfields; number of bits contained in them.  */
  60     int bitsize;
  61     /* Only used for bitfields; position of start of field.
  62        For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  63        For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  64     int bitpos;
  65     /* Frame value is relative to.  In practice, this address is only
  66        used if the value is stored in several registers in other than
  67        the current frame, and these registers have not all been saved
  68        at the same place in memory.  This will be described in the
  69        lval enum above as "lval_reg_frame_relative".  */
  70     CORE_ADDR frame_addr;
  71
  72     /* Type of the value.  */
  73     struct type *type;
  74
  75     /* If a value represents a C++ object, then the `type' field gives
  76        the object's compile-time type.  If the object actually belongs
  77        to some class derived from `type', perhaps with other base
  78        classes and additional members, then `type' is just a subobject
  79        of the real thing, and the full object is probably larger than
  80        `type' would suggest.
  81
  82        If `type' is a dynamic class (i.e. one with a vtable), then GDB
  83        can actually determine the object's run-time type by looking at
  84        the run-time type information in the vtable.  When this
  85        information is available, we may elect to read in the entire
  86        object, for several reasons:
  87
  88          - When printing the value, the user would probably rather see
  89            the full object, not just the limited portion apparent from
  90            the compile-time type.
  91
  92          - If `type' has virtual base classes, then even printing
  93            `type' alone may require reaching outside the `type'
  94            portion of the object to wherever the virtual base class
  95            has been stored.
  96
  97        When we store the entire object, `enclosing_type' is the
  98        run-time type --- the complete object --- and `embedded_offset'
  99        is the offset of `type' within that larger type, in bytes.  The
 100        VALUE_CONTENTS macro takes `embedded_offset' into account, so
 101        most GDB code continues to see the `type' portion of the value,
 102        just as the inferior would.
 103
 104        If `type' is a pointer to an object, then `enclosing_type' is a
 105        pointer to the object's run-time type, and `pointed_to_offset'
 106        is the offset in bytes from the full object to the pointed-to
 107        object --- that is, the value `embedded_offset' would have if
 108        we followed the pointer and fetched the complete object.  (I
 109        don't really see the point.  Why not just determine the
 110        run-time type when you indirect, and avoid the special case?
 111        The contents don't matter until you indirect anyway.)
 112
 113        If we're not doing anything fancy, `enclosing_type' is equal to
 114        `type', and `embedded_offset' is zero, so everything works
 115        normally.  */
 116     struct type *enclosing_type;
 117     int embedded_offset;
 118     int pointed_to_offset;
 119
 120     /* Values are stored in a chain, so that they can be deleted
 121        easily over calls to the inferior.  Values assigned to internal
 122        variables or put into the value history are taken off this
 123        list.  */
 124     struct value *next;
 125
 126     /* ??? When is this used?  */
 127     union
 128       {
 129         CORE_ADDR memaddr;
 130         char *myaddr;
 131       }
 132     substring_addr;
 133
 134     /* Register number if the value is from a register.  Is not kept
 135        if you take a field of a structure that is stored in a
 136        register.  Shouldn't it be?  */
 137     short regno;
 138     /* If zero, contents of this value are in the contents field.
 139        If nonzero, contents are in inferior memory at address
 140        in the location.address field plus the offset field
 141        (and the lval field should be lval_memory).
 142
 143        WARNING: This field is used by the code which handles
 144        watchpoints (see breakpoint.c) to decide whether a particular
 145        value can be watched by hardware watchpoints.  If the lazy flag
 146        is set for some member of a value chain, it is assumed that
 147        this member of the chain doesn't need to be watched as part of
 148        watching the value itself.  This is how GDB avoids watching the
 149        entire struct or array when the user wants to watch a single
 150        struct member or array element.  If you ever change the way
 151        lazy flag is set and reset, be sure to consider this use as
 152        well!  */
 153     char lazy;
 154     /* If nonzero, this is the value of a variable which does not
 155        actually exist in the program.  */
 156     char optimized_out;
 157     /* The BFD section associated with this value.  */
 158     asection *bfd_section;
 159     /* Actual contents of the value.  For use of this value; setting
 160        it uses the stuff above.  Not valid if lazy is nonzero.
 161        Target byte-order.  We force it to be aligned properly for any
 162        possible value.  Note that a value therefore extends beyond
 163        what is declared here.  */
 164     union
 165       {
 166         long contents[1];
 167         double force_double_align;
 168         LONGEST force_longlong_align;
 169         char *literal_data;
 170       }
 171     aligner;
 172     /* Do not add any new members here -- contents above will trash them */
 173   };
 174
 175 typedef struct value *value_ptr;
 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 (value_ptr 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     value_ptr 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 (value_ptr val);
 287
 288 extern DOUBLEST value_as_double (value_ptr val);
 289
 290 extern CORE_ADDR value_as_pointer (value_ptr 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 value_ptr value_from_longest (struct type *type, LONGEST num);
 302
 303 extern value_ptr value_from_pointer (struct type *type, CORE_ADDR addr);
 304
 305 extern value_ptr value_from_double (struct type *type, DOUBLEST num);
 306
 307 extern value_ptr value_from_string (char *string);
 308
 309 extern value_ptr value_at (struct type *type, CORE_ADDR addr,
 310                            asection * sect);
 311
 312 extern value_ptr value_at_lazy (struct type *type, CORE_ADDR addr,
 313                                 asection * sect);
 314
 315 extern value_ptr value_from_register (struct type *type, int regnum,
 316                                       struct frame_info *frame);
 317
 318 extern value_ptr value_of_variable (struct symbol *var, struct block *b);
 319
 320 extern value_ptr value_of_register (int regnum);
 321
 322 extern int symbol_read_needs_frame (struct symbol *);
 323
 324 extern value_ptr read_var_value (struct symbol *var,
 325                                  struct frame_info *frame);
 326
 327 extern value_ptr locate_var_value (struct symbol *var,
 328                                    struct frame_info *frame);
 329
 330 extern value_ptr allocate_value (struct type *type);
 331
 332 extern value_ptr allocate_repeat_value (struct type *type, int count);
 333
 334 extern value_ptr value_change_enclosing_type (value_ptr val, struct type *new_type);
 335
 336 extern value_ptr value_mark (void);
 337
 338 extern void value_free_to_mark (value_ptr mark);
 339
 340 extern value_ptr value_string (char *ptr, int len);
 341 extern value_ptr value_bitstring (char *ptr, int len);
 342
 343 extern value_ptr value_array (int lowbound, int highbound,
 344                               value_ptr * elemvec);
 345
 346 extern value_ptr value_concat (value_ptr arg1, value_ptr arg2);
 347
 348 extern value_ptr value_binop (value_ptr arg1, value_ptr arg2,
 349                               enum exp_opcode op);
 350
 351 extern value_ptr value_add (value_ptr arg1, value_ptr arg2);
 352
 353 extern value_ptr value_sub (value_ptr arg1, value_ptr arg2);
 354
 355 extern value_ptr value_coerce_array (value_ptr arg1);
 356
 357 extern value_ptr value_coerce_function (value_ptr arg1);
 358
 359 extern value_ptr value_ind (value_ptr arg1);
 360
 361 extern value_ptr value_addr (value_ptr arg1);
 362
 363 extern value_ptr value_assign (value_ptr toval, value_ptr fromval);
 364
 365 extern value_ptr value_neg (value_ptr arg1);
 366
 367 extern value_ptr value_complement (value_ptr arg1);
 368
 369 extern value_ptr value_struct_elt (value_ptr * argp, value_ptr * args,
 370                                    char *name,
 371                                    int *static_memfuncp, char *err);
 372
 373 extern value_ptr value_struct_elt_for_reference (struct type *domain,
 374                                                  int offset,
 375                                                  struct type *curtype,
 376                                                  char *name,
 377                                                  struct type *intype);
 378
 379 extern value_ptr value_static_field (struct type *type, int fieldno);
 380
 381 extern struct fn_field *value_find_oload_method_list (value_ptr *, char *,
 382                                                       int, int *, int *,
 383                                                       struct type **, int *);
 384
 385 extern int find_overload_match (struct type **arg_types, int nargs,
 386                                 char *name, int method, int lax,
 387                                 value_ptr obj, struct symbol *fsym,
 388                                 value_ptr * valp, struct symbol **symp,
 389                                 int *staticp);
 390
 391 extern value_ptr value_field (value_ptr arg1, int fieldno);
 392
 393 extern value_ptr value_primitive_field (value_ptr arg1, int offset,
 394                                         int fieldno, struct type *arg_type);
 395
 396
 397 extern struct type *value_rtti_target_type (value_ptr, int *, int *, int *);
 398
 399 extern value_ptr value_full_object (value_ptr, struct type *, int, int, int);
 400
 401 extern value_ptr value_cast (struct type *type, value_ptr arg2);
 402
 403 extern value_ptr value_zero (struct type *type, enum lval_type lv);
 404
 405 extern value_ptr value_repeat (value_ptr arg1, int count);
 406
 407 extern value_ptr value_subscript (value_ptr array, value_ptr idx);
 408
 409 extern value_ptr value_from_vtable_info (value_ptr arg, struct type *type);
 410
 411 extern value_ptr value_being_returned (struct type *valtype,
 412                                        char *retbuf, int struct_return);
 413
 414 extern value_ptr value_in (value_ptr element, value_ptr set);
 415
 416 extern int value_bit_index (struct type *type, char *addr, int index);
 417
 418 extern int using_struct_return (value_ptr function, CORE_ADDR funcaddr,
 419                                 struct type *value_type, int gcc_p);
 420
 421 extern void set_return_value (value_ptr val);
 422
 423 extern value_ptr evaluate_expression (struct expression *exp);
 424
 425 extern value_ptr evaluate_type (struct expression *exp);
 426
 427 extern value_ptr evaluate_subexp_with_coercion (struct expression *,
 428                                                 int *, enum noside);
 429
 430 extern value_ptr parse_and_eval (char *exp);
 431
 432 extern value_ptr 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 value_ptr access_value_history (int num);
 443
 444 extern value_ptr value_of_internalvar (struct internalvar *var);
 445
 446 extern void set_internalvar (struct internalvar *var, value_ptr val);
 447
 448 extern void set_internalvar_component (struct internalvar *var,
 449                                        int offset,
 450                                        int bitpos, int bitsize,
 451                                        value_ptr newvalue);
 452
 453 extern struct internalvar *lookup_internalvar (char *name);
 454
 455 extern int value_equal (value_ptr arg1, value_ptr arg2);
 456
 457 extern int value_less (value_ptr arg1, value_ptr arg2);
 458
 459 extern int value_logical_not (value_ptr arg1);
 460
 461 /* C++ */
 462
 463 extern value_ptr value_of_this (int complain);
 464
 465 extern value_ptr value_x_binop (value_ptr arg1, value_ptr arg2,
 466                                 enum exp_opcode op,
 467                                 enum exp_opcode otherop, enum noside noside);
 468
 469 extern value_ptr value_x_unop (value_ptr arg1, enum exp_opcode op,
 470                                enum noside noside);
 471
 472 extern value_ptr value_fn_field (value_ptr * arg1p, struct fn_field *f,
 473                                  int j, struct type *type, int offset);
 474
 475 extern int binop_user_defined_p (enum exp_opcode op,
 476                                  value_ptr arg1, value_ptr arg2);
 477
 478 extern int unop_user_defined_p (enum exp_opcode op, value_ptr arg1);
 479
 480 extern int destructor_name_p (const char *name, const struct type *type);
 481
 482 #define value_free(val) xfree (val)
 483
 484 extern void free_all_values (void);
 485
 486 extern void release_value (value_ptr val);
 487
 488 extern int record_latest_value (value_ptr val);
 489
 490 extern void
 491 modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize);
 492
 493 extern void type_print (struct type * type, char *varstring,
 494                         struct ui_file * stream, int show);
 495
 496 extern char *baseclass_addr (struct type *type, int index,
 497                              char *valaddr, value_ptr * valuep, int *errp);
 498
 499 extern void print_longest (struct ui_file * stream, int format,
 500                            int use_local, LONGEST val);
 501
 502 extern void print_floating (char *valaddr, struct type * type,
 503                             struct ui_file * stream);
 504
 505 extern int value_print (value_ptr val, struct ui_file *stream, int format,
 506                         enum val_prettyprint pretty);
 507
 508 extern void value_print_array_elements (value_ptr val,
 509                                         struct ui_file *stream,
 510                                         int format,
 511                                         enum val_prettyprint pretty);
 512
 513 extern value_ptr value_release_to_mark (value_ptr 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 (value_ptr, 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 value_ptr value_copy (value_ptr);
 541
 542 extern int baseclass_offset (struct type *, int, char *, CORE_ADDR);
 543
 544 /* From valops.c */
 545
 546 extern value_ptr varying_to_slice (value_ptr);
 547
 548 extern value_ptr value_slice (value_ptr, int, int);
 549
 550 extern value_ptr call_function_by_hand (value_ptr, int, value_ptr *);
 551
 552 extern int default_coerce_float_to_double (struct type *, struct type *);
 553
 554 extern int standard_coerce_float_to_double (struct type *, struct type *);
 555
 556 extern value_ptr value_literal_complex (value_ptr, value_ptr, struct type *);
 557
 558 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 559                                   int *, int *);
 560
 561 extern value_ptr find_function_in_inferior (char *);
 562
 563 extern value_ptr value_allocate_space_in_inferior (int);
 564
 565 extern CORE_ADDR default_push_arguments (int nargs, value_ptr * args,
 566                                          CORE_ADDR sp,
 567                                          int struct_return,
 568                                          CORE_ADDR struct_addr);
 569
 570 #endif /* !defined (VALUE_H) */