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     /* Type of the value.  */
  72     struct type *type;
  73     /* Type of the enclosing object if this is an embedded subobject.
  74        The member embedded_offset gives the real position of the subobject
  75        if type is not the same as enclosing_type.
  76
  77        If the type field is a pointer type, then enclosing_type is
  78        a pointer type pointing to the real (enclosing) type of the target
  79        object. */
  80     struct type *enclosing_type;
  81     /* Values are stored in a chain, so that they can be deleted
  82        easily over calls to the inferior.  Values assigned to internal
  83        variables or put into the value history are taken off this
  84        list.  */
  85     struct value *next;
  86
  87     /* ??? When is this used?  */
  88     union
  89       {
  90         CORE_ADDR memaddr;
  91         char *myaddr;
  92       }
  93     substring_addr;
  94
  95     /* Register number if the value is from a register.  Is not kept
  96        if you take a field of a structure that is stored in a
  97        register.  Shouldn't it be?  */
  98     short regno;
  99     /* If zero, contents of this value are in the contents field.
 100        If nonzero, contents are in inferior memory at address
 101        in the location.address field plus the offset field
 102        (and the lval field should be lval_memory).
 103
 104        WARNING: This field is used by the code which handles
 105        watchpoints (see breakpoint.c) to decide whether a particular
 106        value can be watched by hardware watchpoints.  If the lazy flag
 107        is set for some member of a value chain, it is assumed that
 108        this member of the chain doesn't need to be watched as part of
 109        watching the value itself.  This is how GDB avoids watching the
 110        entire struct or array when the user wants to watch a single
 111        struct member or array element.  If you ever change the way
 112        lazy flag is set and reset, be sure to consider this use as
 113        well!  */
 114     char lazy;
 115     /* If nonzero, this is the value of a variable which does not
 116        actually exist in the program.  */
 117     char optimized_out;
 118     /* If this value represents an object that is embedded inside a
 119        larger object (e.g., a base subobject in C++), this gives the
 120        offset (in bytes) from the start of the contents buffer where
 121        the embedded object begins. This is required because some C++
 122        runtime implementations lay out objects (especially virtual bases
 123        with possibly negative offsets to ancestors).
 124        Note: This may be positive or negative! Also note that this offset
 125        is not used when retrieving contents from target memory; the entire
 126        enclosing object has to be retrieved always, and the offset for
 127        that is given by the member offset above. */
 128     int embedded_offset;
 129     /* If this value represents a pointer to an object that is embedded
 130        in another object, this gives the embedded_offset of the object
 131        that is pointed to. */
 132     int pointed_to_offset;
 133     /* The BFD section associated with this value.  */
 134     asection *bfd_section;
 135     /* Actual contents of the value.  For use of this value; setting
 136        it uses the stuff above.  Not valid if lazy is nonzero.
 137        Target byte-order.  We force it to be aligned properly for any
 138        possible value.  Note that a value therefore extends beyond
 139        what is declared here.  */
 140     union
 141       {
 142         long contents[1];
 143         double force_double_align;
 144         LONGEST force_longlong_align;
 145         char *literal_data;
 146       }
 147     aligner;
 148     /* Do not add any new members here -- contents above will trash them */
 149   };
 150
 151 typedef struct value *value_ptr;
 152
 153 #define VALUE_TYPE(val) (val)->type
 154 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 155 #define VALUE_LAZY(val) (val)->lazy
 156 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 157    the gdb buffer used to hold a copy of the contents of the lval.
 158    VALUE_CONTENTS is used when the contents of the buffer are needed --
 159    it uses value_fetch_lazy() to load the buffer from the process being
 160    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 161    used when data is being stored into the buffer, or when it is
 162    certain that the contents of the buffer are valid.
 163    Note: The contents pointer is adjusted by the offset required to
 164    get to the real subobject, if the value happens to represent
 165    something embedded in a larger run-time object. */
 166
 167 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 168 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 169                              VALUE_CONTENTS_RAW(val))
 170
 171 /* The ALL variants of the above two macros do not adjust the returned
 172    pointer by the embedded_offset value. */
 173
 174 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 175 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 176                                  VALUE_CONTENTS_ALL_RAW(val))
 177
 178
 179 extern int value_fetch_lazy (value_ptr val);
 180
 181 #define VALUE_LVAL(val) (val)->lval
 182 #define VALUE_ADDRESS(val) (val)->location.address
 183 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 184 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 185 #define VALUE_FRAME(val) ((val)->frame_addr)
 186 #define VALUE_OFFSET(val) (val)->offset
 187 #define VALUE_BITSIZE(val) (val)->bitsize
 188 #define VALUE_BITPOS(val) (val)->bitpos
 189 #define VALUE_NEXT(val) (val)->next
 190 #define VALUE_REGNO(val) (val)->regno
 191 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 192 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 193 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 194 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 195
 196 /* Convert a REF to the object referenced. */
 197
 198 #define COERCE_REF(arg)    \
 199 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 200      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 201          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 202                               unpack_pointer (VALUE_TYPE (arg),         \
 203                                               VALUE_CONTENTS (arg)),    \
 204                               VALUE_BFD_SECTION (arg));                 \
 205     } while (0)
 206
 207 /* If ARG is an array, convert it to a pointer.
 208    If ARG is an enum, convert it to an integer.
 209    If ARG is a function, convert it to a function pointer.
 210
 211    References are dereferenced.  */
 212
 213 #define COERCE_ARRAY(arg)    \
 214 do { COERCE_REF(arg);                                                   \
 215   if (current_language->c_style_arrays                                  \
 216       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 217     arg = value_coerce_array (arg);                                     \
 218   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 219     arg = value_coerce_function (arg);                                  \
 220 } while (0)
 221
 222 #define COERCE_NUMBER(arg)  \
 223   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 224
 225 #define COERCE_VARYING_ARRAY(arg, real_arg_type)        \
 226 { if (chill_varying_type (real_arg_type))  \
 227     arg = varying_to_slice (arg), real_arg_type = VALUE_TYPE (arg); }
 228
 229 /* If ARG is an enum, convert it to an integer.  */
 230
 231 #define COERCE_ENUM(arg)   { \
 232   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 233     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 234 }
 235
 236 /* Internal variables (variables for convenience of use of debugger)
 237    are recorded as a chain of these structures.  */
 238
 239 struct internalvar
 240   {
 241     struct internalvar *next;
 242     char *name;
 243     value_ptr value;
 244   };
 245
 246 /* Pointer to member function.  Depends on compiler implementation. */
 247
 248 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 249 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 250 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 251 \f
 252
 253 #include "symtab.h"
 254 #include "gdbtypes.h"
 255 #include "expression.h"
 256
 257 struct frame_info;
 258 struct fn_field;
 259
 260 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 261
 262 extern LONGEST value_as_long (value_ptr val);
 263
 264 extern DOUBLEST value_as_double (value_ptr val);
 265
 266 extern CORE_ADDR value_as_pointer (value_ptr val);
 267
 268 extern LONGEST unpack_long (struct type *type, char *valaddr);
 269
 270 extern DOUBLEST unpack_double (struct type *type, char *valaddr, int *invp);
 271
 272 extern CORE_ADDR unpack_pointer (struct type *type, char *valaddr);
 273
 274 extern LONGEST unpack_field_as_long (struct type *type, char *valaddr,
 275                                      int fieldno);
 276
 277 extern value_ptr value_from_longest (struct type *type, LONGEST num);
 278
 279 extern value_ptr value_from_pointer (struct type *type, CORE_ADDR addr);
 280
 281 extern value_ptr value_from_double (struct type *type, DOUBLEST num);
 282
 283 extern value_ptr value_from_string (char *string);
 284
 285 extern value_ptr value_at (struct type *type, CORE_ADDR addr,
 286                            asection * sect);
 287
 288 extern value_ptr value_at_lazy (struct type *type, CORE_ADDR addr,
 289                                 asection * sect);
 290
 291 extern value_ptr value_from_register (struct type *type, int regnum,
 292                                       struct frame_info *frame);
 293
 294 extern value_ptr value_of_variable (struct symbol *var, struct block *b);
 295
 296 extern value_ptr value_of_register (int regnum);
 297
 298 extern int symbol_read_needs_frame (struct symbol *);
 299
 300 extern value_ptr read_var_value (struct symbol *var,
 301                                  struct frame_info *frame);
 302
 303 extern value_ptr locate_var_value (struct symbol *var,
 304                                    struct frame_info *frame);
 305
 306 extern value_ptr allocate_value (struct type *type);
 307
 308 extern value_ptr allocate_repeat_value (struct type *type, int count);
 309
 310 extern value_ptr value_change_enclosing_type (value_ptr val, struct type *new_type);
 311
 312 extern value_ptr value_mark (void);
 313
 314 extern void value_free_to_mark (value_ptr mark);
 315
 316 extern value_ptr value_string (char *ptr, int len);
 317 extern value_ptr value_bitstring (char *ptr, int len);
 318
 319 extern value_ptr value_array (int lowbound, int highbound,
 320                               value_ptr * elemvec);
 321
 322 extern value_ptr value_concat (value_ptr arg1, value_ptr arg2);
 323
 324 extern value_ptr value_binop (value_ptr arg1, value_ptr arg2,
 325                               enum exp_opcode op);
 326
 327 extern value_ptr value_add (value_ptr arg1, value_ptr arg2);
 328
 329 extern value_ptr value_sub (value_ptr arg1, value_ptr arg2);
 330
 331 extern value_ptr value_coerce_array (value_ptr arg1);
 332
 333 extern value_ptr value_coerce_function (value_ptr arg1);
 334
 335 extern value_ptr value_ind (value_ptr arg1);
 336
 337 extern value_ptr value_addr (value_ptr arg1);
 338
 339 extern value_ptr value_assign (value_ptr toval, value_ptr fromval);
 340
 341 extern value_ptr value_neg (value_ptr arg1);
 342
 343 extern value_ptr value_complement (value_ptr arg1);
 344
 345 extern value_ptr value_struct_elt (value_ptr * argp, value_ptr * args,
 346                                    char *name,
 347                                    int *static_memfuncp, char *err);
 348
 349 extern value_ptr value_struct_elt_for_reference (struct type *domain,
 350                                                  int offset,
 351                                                  struct type *curtype,
 352                                                  char *name,
 353                                                  struct type *intype);
 354
 355 extern value_ptr value_static_field (struct type *type, int fieldno);
 356
 357 extern struct fn_field *value_find_oload_method_list (value_ptr *, char *,
 358                                                       int, int *, int *,
 359                                                       struct type **, int *);
 360
 361 extern int find_overload_match (struct type **arg_types, int nargs,
 362                                 char *name, int method, int lax,
 363                                 value_ptr obj, struct symbol *fsym,
 364                                 value_ptr * valp, struct symbol **symp,
 365                                 int *staticp);
 366
 367 extern value_ptr value_field (value_ptr arg1, int fieldno);
 368
 369 extern value_ptr value_primitive_field (value_ptr arg1, int offset,
 370                                         int fieldno, struct type *arg_type);
 371
 372
 373 extern struct type *value_rtti_target_type (value_ptr, int *, int *, int *);
 374
 375 extern value_ptr value_full_object (value_ptr, struct type *, int, int, int);
 376
 377 extern value_ptr value_cast (struct type *type, value_ptr arg2);
 378
 379 extern value_ptr value_zero (struct type *type, enum lval_type lv);
 380
 381 extern value_ptr value_repeat (value_ptr arg1, int count);
 382
 383 extern value_ptr value_subscript (value_ptr array, value_ptr idx);
 384
 385 extern value_ptr value_from_vtable_info (value_ptr arg, struct type *type);
 386
 387 extern value_ptr value_being_returned (struct type *valtype,
 388                                        char *retbuf, int struct_return);
 389
 390 extern value_ptr value_in (value_ptr element, value_ptr set);
 391
 392 extern int value_bit_index (struct type *type, char *addr, int index);
 393
 394 extern int using_struct_return (value_ptr function, CORE_ADDR funcaddr,
 395                                 struct type *value_type, int gcc_p);
 396
 397 extern void set_return_value (value_ptr val);
 398
 399 extern value_ptr evaluate_expression (struct expression *exp);
 400
 401 extern value_ptr evaluate_type (struct expression *exp);
 402
 403 extern value_ptr evaluate_subexp_with_coercion (struct expression *,
 404                                                 int *, enum noside);
 405
 406 extern value_ptr parse_and_eval (char *exp);
 407
 408 extern value_ptr parse_to_comma_and_eval (char **expp);
 409
 410 extern struct type *parse_and_eval_type (char *p, int length);
 411
 412 extern CORE_ADDR parse_and_eval_address (char *exp);
 413
 414 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 415
 416 extern LONGEST parse_and_eval_long (char *exp);
 417
 418 extern value_ptr access_value_history (int num);
 419
 420 extern value_ptr value_of_internalvar (struct internalvar *var);
 421
 422 extern void set_internalvar (struct internalvar *var, value_ptr val);
 423
 424 extern void set_internalvar_component (struct internalvar *var,
 425                                        int offset,
 426                                        int bitpos, int bitsize,
 427                                        value_ptr newvalue);
 428
 429 extern struct internalvar *lookup_internalvar (char *name);
 430
 431 extern int value_equal (value_ptr arg1, value_ptr arg2);
 432
 433 extern int value_less (value_ptr arg1, value_ptr arg2);
 434
 435 extern int value_logical_not (value_ptr arg1);
 436
 437 /* C++ */
 438
 439 extern value_ptr value_of_this (int complain);
 440
 441 extern value_ptr value_x_binop (value_ptr arg1, value_ptr arg2,
 442                                 enum exp_opcode op,
 443                                 enum exp_opcode otherop, enum noside noside);
 444
 445 extern value_ptr value_x_unop (value_ptr arg1, enum exp_opcode op,
 446                                enum noside noside);
 447
 448 extern value_ptr value_fn_field (value_ptr * arg1p, struct fn_field *f,
 449                                  int j, struct type *type, int offset);
 450
 451 extern int binop_user_defined_p (enum exp_opcode op,
 452                                  value_ptr arg1, value_ptr arg2);
 453
 454 extern int unop_user_defined_p (enum exp_opcode op, value_ptr arg1);
 455
 456 extern int destructor_name_p (const char *name, const struct type *type);
 457
 458 #define value_free(val) xfree (val)
 459
 460 extern void free_all_values (void);
 461
 462 extern void release_value (value_ptr val);
 463
 464 extern int record_latest_value (value_ptr val);
 465
 466 extern void
 467 modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize);
 468
 469 extern void type_print (struct type * type, char *varstring,
 470                         struct ui_file * stream, int show);
 471
 472 extern char *baseclass_addr (struct type *type, int index,
 473                              char *valaddr, value_ptr * valuep, int *errp);
 474
 475 extern void print_longest (struct ui_file * stream, int format,
 476                            int use_local, LONGEST val);
 477
 478 extern void print_floating (char *valaddr, struct type * type,
 479                             struct ui_file * stream);
 480
 481 extern int value_print (value_ptr val, struct ui_file *stream, int format,
 482                         enum val_prettyprint pretty);
 483
 484 extern void value_print_array_elements (value_ptr val,
 485                                         struct ui_file *stream,
 486                                         int format,
 487                                         enum val_prettyprint pretty);
 488
 489 extern value_ptr value_release_to_mark (value_ptr mark);
 490
 491 extern int val_print (struct type * type, char *valaddr,
 492                       int embedded_offset, CORE_ADDR address,
 493                       struct ui_file * stream, int format,
 494                       int deref_ref, int recurse,
 495                       enum val_prettyprint pretty);
 496
 497 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 498
 499 extern void print_variable_value (struct symbol * var,
 500                                   struct frame_info * frame,
 501                                   struct ui_file *stream);
 502
 503 extern int check_field (value_ptr, const char *);
 504
 505 extern void typedef_print (struct type * type, struct symbol * news,
 506                              struct ui_file * stream);
 507
 508 extern char *internalvar_name (struct internalvar *var);
 509
 510 extern void clear_value_history (void);
 511
 512 extern void clear_internalvars (void);
 513
 514 /* From values.c */
 515
 516 extern value_ptr value_copy (value_ptr);
 517
 518 extern int baseclass_offset (struct type *, int, char *, CORE_ADDR);
 519
 520 /* From valops.c */
 521
 522 extern value_ptr varying_to_slice (value_ptr);
 523
 524 extern value_ptr value_slice (value_ptr, int, int);
 525
 526 extern value_ptr call_function_by_hand (value_ptr, int, value_ptr *);
 527
 528 extern int default_coerce_float_to_double (struct type *, struct type *);
 529
 530 extern int standard_coerce_float_to_double (struct type *, struct type *);
 531
 532 extern value_ptr value_literal_complex (value_ptr, value_ptr, struct type *);
 533
 534 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 535                                   int *, int *);
 536
 537 extern value_ptr find_function_in_inferior (char *);
 538
 539 extern value_ptr value_allocate_space_in_inferior (int);
 540
 541 extern CORE_ADDR default_push_arguments (int nargs, value_ptr * args,
 542                                          CORE_ADDR sp,
 543                                          int struct_return,
 544                                          CORE_ADDR struct_addr);
 545
 546 #endif /* !defined (VALUE_H) */