gdb/value.h

   1 /* Definitions for values of C expressions, for GDB.
   2    Copyright 1986, 1987, 1989, 1992-1996, 2000 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #if !defined (VALUE_H)
  22 #define VALUE_H 1
  23
  24 /*
  25  * The structure which defines the type of a value.  It should never
  26  * be possible for a program lval value to survive over a call to the inferior
  27  * (ie to be put into the history list or an internal variable).
  28  */
  29
  30 struct value
  31   {
  32     /* Type of value; either not an lval, or one of the various
  33        different possible kinds of lval.  */
  34     enum lval_type lval;
  35     /* Is it modifiable?  Only relevant if lval != not_lval.  */
  36     int modifiable;
  37     /* Location of value (if lval).  */
  38     union
  39       {
  40         /* If lval == lval_memory, this is the address in the inferior.
  41            If lval == lval_register, this is the byte offset into the
  42            registers structure.  */
  43         CORE_ADDR address;
  44         /* Pointer to internal variable.  */
  45         struct internalvar *internalvar;
  46         /* Number of register.  Only used with
  47            lval_reg_frame_relative.  */
  48         int regnum;
  49       }
  50     location;
  51     /* Describes offset of a value within lval of a structure in bytes.
  52        If lval == lval_memory, this is an offset to the address.
  53        If lval == lval_register, this is a further offset from
  54           location.address within the registers structure.
  55        Note also the member embedded_offset below.  */
  56     int offset;
  57     /* Only used for bitfields; number of bits contained in them.  */
  58     int bitsize;
  59     /* Only used for bitfields; position of start of field.
  60        For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB.
  61        For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */
  62     int bitpos;
  63     /* Frame value is relative to.  In practice, this address is only
  64        used if the value is stored in several registers in other than
  65        the current frame, and these registers have not all been saved
  66        at the same place in memory.  This will be described in the
  67        lval enum above as "lval_reg_frame_relative".  */
  68     CORE_ADDR frame_addr;
  69     /* Type of the value.  */
  70     struct type *type;
  71     /* Type of the enclosing object if this is an embedded subobject.
  72        The member embedded_offset gives the real position of the subobject
  73        if type is not the same as enclosing_type.
  74
  75        If the type field is a pointer type, then enclosing_type is
  76        a pointer type pointing to the real (enclosing) type of the target
  77        object. */
  78     struct type *enclosing_type;
  79     /* Values are stored in a chain, so that they can be deleted
  80        easily over calls to the inferior.  Values assigned to internal
  81        variables or put into the value history are taken off this
  82        list.  */
  83     struct value *next;
  84
  85     /* ??? When is this used?  */
  86     union
  87       {
  88         CORE_ADDR memaddr;
  89         char *myaddr;
  90       }
  91     substring_addr;
  92
  93     /* Register number if the value is from a register.  Is not kept
  94        if you take a field of a structure that is stored in a
  95        register.  Shouldn't it be?  */
  96     short regno;
  97     /* If zero, contents of this value are in the contents field.
  98        If nonzero, contents are in inferior memory at address
  99        in the location.address field plus the offset field
 100        (and the lval field should be lval_memory).
 101
 102        WARNING: This field is used by the code which handles
 103        watchpoints (see breakpoint.c) to decide whether a particular
 104        value can be watched by hardware watchpoints.  If the lazy flag
 105        is set for some member of a value chain, it is assumed that
 106        this member of the chain doesn't need to be watched as part of
 107        watching the value itself.  This is how GDB avoids watching the
 108        entire struct or array when the user wants to watch a single
 109        struct member or array element.  If you ever change the way
 110        lazy flag is set and reset, be sure to consider this use as
 111        well!  */
 112     char lazy;
 113     /* If nonzero, this is the value of a variable which does not
 114        actually exist in the program.  */
 115     char optimized_out;
 116     /* If this value represents an object that is embedded inside a
 117        larger object (e.g., a base subobject in C++), this gives the
 118        offset (in bytes) from the start of the contents buffer where
 119        the embedded object begins. This is required because some C++
 120        runtime implementations lay out objects (especially virtual bases
 121        with possibly negative offsets to ancestors).
 122        Note: This may be positive or negative! Also note that this offset
 123        is not used when retrieving contents from target memory; the entire
 124        enclosing object has to be retrieved always, and the offset for
 125        that is given by the member offset above. */
 126     int embedded_offset;
 127     /* If this value represents a pointer to an object that is embedded
 128        in another object, this gives the embedded_offset of the object
 129        that is pointed to. */
 130     int pointed_to_offset;
 131     /* The BFD section associated with this value.  */
 132     asection *bfd_section;
 133     /* Actual contents of the value.  For use of this value; setting
 134        it uses the stuff above.  Not valid if lazy is nonzero.
 135        Target byte-order.  We force it to be aligned properly for any
 136        possible value.  Note that a value therefore extends beyond
 137        what is declared here.  */
 138     union
 139       {
 140         long contents[1];
 141         double force_double_align;
 142         LONGEST force_longlong_align;
 143         char *literal_data;
 144       }
 145     aligner;
 146     /* Do not add any new members here -- contents above will trash them */
 147   };
 148
 149 typedef struct value *value_ptr;
 150
 151 #define VALUE_TYPE(val) (val)->type
 152 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type
 153 #define VALUE_LAZY(val) (val)->lazy
 154 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of
 155    the gdb buffer used to hold a copy of the contents of the lval.
 156    VALUE_CONTENTS is used when the contents of the buffer are needed --
 157    it uses value_fetch_lazy() to load the buffer from the process being
 158    debugged if it hasn't already been loaded.  VALUE_CONTENTS_RAW is
 159    used when data is being stored into the buffer, or when it is
 160    certain that the contents of the buffer are valid.
 161    Note: The contents pointer is adjusted by the offset required to
 162    get to the real subobject, if the value happens to represent
 163    something embedded in a larger run-time object. */
 164
 165 #define VALUE_CONTENTS_RAW(val) ((char *) (val)->aligner.contents + (val)->embedded_offset)
 166 #define VALUE_CONTENTS(val) ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)),\
 167                              VALUE_CONTENTS_RAW(val))
 168
 169 /* The ALL variants of the above two macros do not adjust the returned
 170    pointer by the embedded_offset value. */
 171
 172 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents)
 173 #define VALUE_CONTENTS_ALL(val) ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)),\
 174                                  VALUE_CONTENTS_ALL_RAW(val))
 175
 176
 177 extern int value_fetch_lazy (value_ptr val);
 178
 179 #define VALUE_LVAL(val) (val)->lval
 180 #define VALUE_ADDRESS(val) (val)->location.address
 181 #define VALUE_INTERNALVAR(val) (val)->location.internalvar
 182 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum)
 183 #define VALUE_FRAME(val) ((val)->frame_addr)
 184 #define VALUE_OFFSET(val) (val)->offset
 185 #define VALUE_BITSIZE(val) (val)->bitsize
 186 #define VALUE_BITPOS(val) (val)->bitpos
 187 #define VALUE_NEXT(val) (val)->next
 188 #define VALUE_REGNO(val) (val)->regno
 189 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out)
 190 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset)
 191 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset)
 192 #define VALUE_BFD_SECTION(val) ((val)->bfd_section)
 193
 194 /* Convert a REF to the object referenced. */
 195
 196 #define COERCE_REF(arg)    \
 197 do { struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg));\
 198      if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF)               \
 199          arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp),    \
 200                               unpack_pointer (VALUE_TYPE (arg),         \
 201                                               VALUE_CONTENTS (arg)),    \
 202                               VALUE_BFD_SECTION (arg));                 \
 203     } while (0)
 204
 205 /* If ARG is an array, convert it to a pointer.
 206    If ARG is an enum, convert it to an integer.
 207    If ARG is a function, convert it to a function pointer.
 208
 209    References are dereferenced.  */
 210
 211 #define COERCE_ARRAY(arg)    \
 212 do { COERCE_REF(arg);                                                   \
 213   if (current_language->c_style_arrays                                  \
 214       && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY)               \
 215     arg = value_coerce_array (arg);                                     \
 216   if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC)                   \
 217     arg = value_coerce_function (arg);                                  \
 218 } while (0)
 219
 220 #define COERCE_NUMBER(arg)  \
 221   do { COERCE_ARRAY(arg);  COERCE_ENUM(arg); } while (0)
 222
 223 #define COERCE_VARYING_ARRAY(arg, real_arg_type)        \
 224 { if (chill_varying_type (real_arg_type))  \
 225     arg = varying_to_slice (arg), real_arg_type = VALUE_TYPE (arg); }
 226
 227 /* If ARG is an enum, convert it to an integer.  */
 228
 229 #define COERCE_ENUM(arg)   { \
 230   if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM)   \
 231     arg = value_cast (builtin_type_unsigned_int, arg);                  \
 232 }
 233
 234 /* Internal variables (variables for convenience of use of debugger)
 235    are recorded as a chain of these structures.  */
 236
 237 struct internalvar
 238   {
 239     struct internalvar *next;
 240     char *name;
 241     value_ptr value;
 242   };
 243
 244 /* Pointer to member function.  Depends on compiler implementation. */
 245
 246 #define METHOD_PTR_IS_VIRTUAL(ADDR)  ((ADDR) & 0x80000000)
 247 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET))
 248 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR))
 249 \f
 250
 251 #include "symtab.h"
 252 #include "gdbtypes.h"
 253 #include "expression.h"
 254
 255 struct frame_info;
 256 struct fn_field;
 257
 258 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int);
 259
 260 extern LONGEST value_as_long (value_ptr val);
 261
 262 extern DOUBLEST value_as_double (value_ptr val);
 263
 264 extern CORE_ADDR value_as_pointer (value_ptr val);
 265
 266 extern LONGEST unpack_long (struct type *type, char *valaddr);
 267
 268 extern DOUBLEST unpack_double (struct type *type, char *valaddr, int *invp);
 269
 270 extern CORE_ADDR unpack_pointer (struct type *type, char *valaddr);
 271
 272 extern LONGEST unpack_field_as_long (struct type *type, char *valaddr,
 273                                      int fieldno);
 274
 275 extern value_ptr value_from_longest (struct type *type, LONGEST num);
 276
 277 extern value_ptr value_from_pointer (struct type *type, CORE_ADDR addr);
 278
 279 extern value_ptr value_from_double (struct type *type, DOUBLEST num);
 280
 281 extern value_ptr value_from_string (char *string);
 282
 283 extern value_ptr value_at (struct type *type, CORE_ADDR addr,
 284                            asection * sect);
 285
 286 extern value_ptr value_at_lazy (struct type *type, CORE_ADDR addr,
 287                                 asection * sect);
 288
 289 extern value_ptr value_from_register (struct type *type, int regnum,
 290                                       struct frame_info *frame);
 291
 292 extern value_ptr value_of_variable (struct symbol *var, struct block *b);
 293
 294 extern value_ptr value_of_register (int regnum);
 295
 296 extern int symbol_read_needs_frame (struct symbol *);
 297
 298 extern value_ptr read_var_value (struct symbol *var,
 299                                  struct frame_info *frame);
 300
 301 extern value_ptr locate_var_value (struct symbol *var,
 302                                    struct frame_info *frame);
 303
 304 extern value_ptr allocate_value (struct type *type);
 305
 306 extern value_ptr allocate_repeat_value (struct type *type, int count);
 307
 308 extern value_ptr value_mark (void);
 309
 310 extern void value_free_to_mark (value_ptr mark);
 311
 312 extern value_ptr value_string (char *ptr, int len);
 313 extern value_ptr value_bitstring (char *ptr, int len);
 314
 315 extern value_ptr value_array (int lowbound, int highbound,
 316                               value_ptr * elemvec);
 317
 318 extern value_ptr value_concat (value_ptr arg1, value_ptr arg2);
 319
 320 extern value_ptr value_binop (value_ptr arg1, value_ptr arg2,
 321                               enum exp_opcode op);
 322
 323 extern value_ptr value_add (value_ptr arg1, value_ptr arg2);
 324
 325 extern value_ptr value_sub (value_ptr arg1, value_ptr arg2);
 326
 327 extern value_ptr value_coerce_array (value_ptr arg1);
 328
 329 extern value_ptr value_coerce_function (value_ptr arg1);
 330
 331 extern value_ptr value_ind (value_ptr arg1);
 332
 333 extern value_ptr value_addr (value_ptr arg1);
 334
 335 extern value_ptr value_assign (value_ptr toval, value_ptr fromval);
 336
 337 extern value_ptr value_neg (value_ptr arg1);
 338
 339 extern value_ptr value_complement (value_ptr arg1);
 340
 341 extern value_ptr value_struct_elt (value_ptr * argp, value_ptr * args,
 342                                    char *name,
 343                                    int *static_memfuncp, char *err);
 344
 345 extern value_ptr value_struct_elt_for_reference (struct type *domain,
 346                                                  int offset,
 347                                                  struct type *curtype,
 348                                                  char *name,
 349                                                  struct type *intype);
 350
 351 extern value_ptr value_static_field (struct type *type, int fieldno);
 352
 353 extern struct fn_field *value_find_oload_method_list (value_ptr *, char *,
 354                                                       int, int *, int *,
 355                                                       struct type **, int *);
 356
 357 extern int find_overload_match (struct type **arg_types, int nargs,
 358                                 char *name, int method, int lax,
 359                                 value_ptr obj, struct symbol *fsym,
 360                                 value_ptr * valp, struct symbol **symp,
 361                                 int *staticp);
 362
 363 extern value_ptr value_field (value_ptr arg1, int fieldno);
 364
 365 extern value_ptr value_primitive_field (value_ptr arg1, int offset,
 366                                         int fieldno, struct type *arg_type);
 367
 368 extern struct type *value_rtti_type (value_ptr, int *, int *, int *);
 369
 370 extern struct type *value_rtti_target_type (value_ptr, int *, int *, int *);
 371
 372 extern value_ptr value_full_object (value_ptr, struct type *, int, int, int);
 373
 374 extern value_ptr value_cast (struct type *type, value_ptr arg2);
 375
 376 extern value_ptr value_zero (struct type *type, enum lval_type lv);
 377
 378 extern value_ptr value_repeat (value_ptr arg1, int count);
 379
 380 extern value_ptr value_subscript (value_ptr array, value_ptr idx);
 381
 382 extern value_ptr value_from_vtable_info (value_ptr arg, struct type *type);
 383
 384 extern value_ptr value_being_returned (struct type *valtype,
 385                                        char *retbuf, int struct_return);
 386
 387 extern value_ptr value_in (value_ptr element, value_ptr set);
 388
 389 extern int value_bit_index (struct type *type, char *addr, int index);
 390
 391 extern int using_struct_return (value_ptr function, CORE_ADDR funcaddr,
 392                                 struct type *value_type, int gcc_p);
 393
 394 extern void set_return_value (value_ptr val);
 395
 396 extern value_ptr evaluate_expression (struct expression *exp);
 397
 398 extern value_ptr evaluate_type (struct expression *exp);
 399
 400 extern value_ptr evaluate_subexp_with_coercion (struct expression *,
 401                                                 int *, enum noside);
 402
 403 extern value_ptr parse_and_eval (char *exp);
 404
 405 extern value_ptr parse_to_comma_and_eval (char **expp);
 406
 407 extern struct type *parse_and_eval_type (char *p, int length);
 408
 409 extern CORE_ADDR parse_and_eval_address (char *exp);
 410
 411 extern CORE_ADDR parse_and_eval_address_1 (char **expptr);
 412
 413 extern value_ptr access_value_history (int num);
 414
 415 extern value_ptr value_of_internalvar (struct internalvar *var);
 416
 417 extern void set_internalvar (struct internalvar *var, value_ptr val);
 418
 419 extern void set_internalvar_component (struct internalvar *var,
 420                                        int offset,
 421                                        int bitpos, int bitsize,
 422                                        value_ptr newvalue);
 423
 424 extern struct internalvar *lookup_internalvar (char *name);
 425
 426 extern int value_equal (value_ptr arg1, value_ptr arg2);
 427
 428 extern int value_less (value_ptr arg1, value_ptr arg2);
 429
 430 extern int value_logical_not (value_ptr arg1);
 431
 432 /* C++ */
 433
 434 extern value_ptr value_of_this (int complain);
 435
 436 extern value_ptr value_x_binop (value_ptr arg1, value_ptr arg2,
 437                                 enum exp_opcode op,
 438                                 enum exp_opcode otherop, enum noside noside);
 439
 440 extern value_ptr value_x_unop (value_ptr arg1, enum exp_opcode op,
 441                                enum noside noside);
 442
 443 extern value_ptr value_fn_field (value_ptr * arg1p, struct fn_field *f,
 444                                  int j, struct type *type, int offset);
 445
 446 extern value_ptr value_virtual_fn_field (value_ptr * arg1p,
 447                                          struct fn_field *f, int j,
 448                                          struct type *type, int offset);
 449
 450 extern int binop_user_defined_p (enum exp_opcode op,
 451                                  value_ptr arg1, value_ptr arg2);
 452
 453 extern int unop_user_defined_p (enum exp_opcode op, value_ptr arg1);
 454
 455 extern int destructor_name_p (const char *name, const struct type *type);
 456
 457 #define value_free(val) free ((PTR)val)
 458
 459 extern void free_all_values (void);
 460
 461 extern void release_value (value_ptr val);
 462
 463 extern int record_latest_value (value_ptr val);
 464
 465 extern void registers_changed (void);
 466
 467 extern void read_register_bytes (int regbyte, char *myaddr, int len);
 468
 469 extern void write_register_bytes (int regbyte, char *myaddr, int len);
 470
 471 extern void read_register_gen (int regno, char *myaddr);
 472
 473 extern void write_register_gen (int regno, char *myaddr);
 474
 475 /* Rename to read_unsigned_register()? */
 476 extern ULONGEST read_register (int regno);
 477
 478 extern LONGEST read_signed_register (int regno);
 479
 480 /* Rename to read_unsigned_register_pid()? */
 481 extern ULONGEST read_register_pid (int regno, int pid);
 482
 483 extern LONGEST read_signed_register_pid (int regno, int pid);
 484
 485 extern void write_register (int regno, LONGEST val);
 486
 487 extern void write_register_pid (int regno, CORE_ADDR val, int pid);
 488
 489 extern void supply_register (int regno, char *val);
 490
 491 extern int register_cached (int regno);
 492
 493 extern void register_changed (int regnum);
 494
 495 extern void get_saved_register (char *raw_buffer, int *optimized,
 496                                 CORE_ADDR * addrp,
 497                                 struct frame_info *frame,
 498                                 int regnum, enum lval_type *lval);
 499
 500 extern void
 501 modify_field (char *addr, LONGEST fieldval, int bitpos, int bitsize);
 502
 503 extern void type_print (struct type * type, char *varstring,
 504                         struct ui_file * stream, int show);
 505
 506 extern char *baseclass_addr (struct type *type, int index,
 507                              char *valaddr, value_ptr * valuep, int *errp);
 508
 509 extern void print_longest (struct ui_file * stream, int format,
 510                            int use_local, LONGEST val);
 511
 512 extern void print_floating (char *valaddr, struct type * type,
 513                             struct ui_file * stream);
 514
 515 extern int value_print (value_ptr val, struct ui_file *stream, int format,
 516                         enum val_prettyprint pretty);
 517
 518 extern void value_print_array_elements (value_ptr val,
 519                                         struct ui_file *stream,
 520                                         int format,
 521                                         enum val_prettyprint pretty);
 522
 523 extern value_ptr value_release_to_mark (value_ptr mark);
 524
 525 extern int val_print (struct type * type, char *valaddr,
 526                       int embedded_offset, CORE_ADDR address,
 527                       struct ui_file * stream, int format,
 528                       int deref_ref, int recurse,
 529                       enum val_prettyprint pretty);
 530
 531 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream);
 532
 533 extern void print_variable_value (struct symbol * var,
 534                                   struct frame_info * frame,
 535                                   struct ui_file *stream);
 536
 537 extern int check_field (value_ptr, const char *);
 538
 539 extern void typedef_print (struct type * type, struct symbol * news,
 540                              struct ui_file * stream);
 541
 542 extern char *internalvar_name (struct internalvar *var);
 543
 544 extern void clear_value_history (void);
 545
 546 extern void clear_internalvars (void);
 547
 548 /* From values.c */
 549
 550 extern value_ptr value_copy (value_ptr);
 551
 552 extern int baseclass_offset (struct type *, int, char *, CORE_ADDR);
 553
 554 /* From valops.c */
 555
 556 extern value_ptr varying_to_slice (value_ptr);
 557
 558 extern value_ptr value_slice (value_ptr, int, int);
 559
 560 extern value_ptr call_function_by_hand (value_ptr, int, value_ptr *);
 561
 562 extern int default_coerce_float_to_double (struct type *, struct type *);
 563
 564 extern int standard_coerce_float_to_double (struct type *, struct type *);
 565
 566 extern value_ptr value_literal_complex (value_ptr, value_ptr, struct type *);
 567
 568 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int,
 569                                   int *, int *);
 570
 571 extern value_ptr find_function_in_inferior (char *);
 572
 573 extern value_ptr value_allocate_space_in_inferior (int);
 574
 575 extern CORE_ADDR default_push_arguments (int nargs, value_ptr * args,
 576                                          CORE_ADDR sp,
 577                                          int struct_return,
 578                                          CORE_ADDR struct_addr);
 579
 580 #endif /* !defined (VALUE_H) */