1 /* Definitions for values of C expressions, for GDB. 2 3 Copyright 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 4 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 5 Free Software Foundation, Inc. 6 7 This file is part of GDB. 8 9 This program is free software; you can redistribute it and/or modify 10 it under the terms of the GNU General Public License as published by 11 the Free Software Foundation; either version 2 of the License, or 12 (at your option) any later version. 13 14 This program is distributed in the hope that it will be useful, 15 but WITHOUT ANY WARRANTY; without even the implied warranty of 16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 GNU General Public License for more details. 18 19 You should have received a copy of the GNU General Public License 20 along with this program; if not, write to the Free Software 21 Foundation, Inc., 59 Temple Place - Suite 330, 22 Boston, MA 02111-1307, USA. */ 23 24 #if !defined (VALUE_H) 25 #define VALUE_H 1 26 27 #include "doublest.h" 28 #include "frame.h" /* For struct frame_id. */ 29 30 struct block; 31 struct expression; 32 struct regcache; 33 struct symbol; 34 struct type; 35 struct ui_file; 36 37 /* The structure which defines the type of a value. It should never 38 be possible for a program lval value to survive over a call to the 39 inferior (i.e. to be put into the history list or an internal 40 variable). */ 41 42 struct value 43 { 44 /* Type of value; either not an lval, or one of the various 45 different possible kinds of lval. */ 46 enum lval_type lval; 47 48 /* Is it modifiable? Only relevant if lval != not_lval. */ 49 int modifiable; 50 51 /* Location of value (if lval). */ 52 union 53 { 54 /* If lval == lval_memory, this is the address in the inferior. 55 If lval == lval_register, this is the byte offset into the 56 registers structure. */ 57 CORE_ADDR address; 58 59 /* Pointer to internal variable. */ 60 struct internalvar *internalvar; 61 62 /* Number of register. Only used with lval_reg_frame_relative. */ 63 int regnum; 64 } location; 65 66 /* Describes offset of a value within lval of a structure in bytes. 67 If lval == lval_memory, this is an offset to the address. 68 If lval == lval_register, this is a further offset from 69 location.address within the registers structure. 70 Note also the member embedded_offset below. */ 71 int offset; 72 73 /* Only used for bitfields; number of bits contained in them. */ 74 int bitsize; 75 76 /* Only used for bitfields; position of start of field. 77 For BITS_BIG_ENDIAN=0 targets, it is the position of the LSB. 78 For BITS_BIG_ENDIAN=1 targets, it is the position of the MSB. */ 79 int bitpos; 80 81 /* Frame value is relative to. In practice, this ID is only used if 82 the value is stored in several registers in other than the 83 current frame, and these registers have not all been saved at the 84 same place in memory. This will be described in the lval enum 85 above as "lval_reg_frame_relative". */ 86 struct frame_id frame_id; 87 88 /* Type of the value. */ 89 struct type *type; 90 91 /* If a value represents a C++ object, then the `type' field gives 92 the object's compile-time type. If the object actually belongs 93 to some class derived from `type', perhaps with other base 94 classes and additional members, then `type' is just a subobject 95 of the real thing, and the full object is probably larger than 96 `type' would suggest. 97 98 If `type' is a dynamic class (i.e. one with a vtable), then GDB 99 can actually determine the object's run-time type by looking at 100 the run-time type information in the vtable. When this 101 information is available, we may elect to read in the entire 102 object, for several reasons: 103 104 - When printing the value, the user would probably rather see the 105 full object, not just the limited portion apparent from the 106 compile-time type. 107 108 - If `type' has virtual base classes, then even printing `type' 109 alone may require reaching outside the `type' portion of the 110 object to wherever the virtual base class has been stored. 111 112 When we store the entire object, `enclosing_type' is the run-time 113 type -- the complete object -- and `embedded_offset' is the 114 offset of `type' within that larger type, in bytes. The 115 VALUE_CONTENTS macro takes `embedded_offset' into account, so 116 most GDB code continues to see the `type' portion of the value, 117 just as the inferior would. 118 119 If `type' is a pointer to an object, then `enclosing_type' is a 120 pointer to the object's run-time type, and `pointed_to_offset' is 121 the offset in bytes from the full object to the pointed-to object 122 -- that is, the value `embedded_offset' would have if we 123 followed the pointer and fetched the complete object. (I don't 124 really see the point. Why not just determine the run-time type 125 when you indirect, and avoid the special case? The contents 126 don't matter until you indirect anyway.) 127 128 If we're not doing anything fancy, `enclosing_type' is equal to 129 `type', and `embedded_offset' is zero, so everything works 130 normally. */ 131 struct type *enclosing_type; 132 int embedded_offset; 133 int pointed_to_offset; 134 135 /* Values are stored in a chain, so that they can be deleted 136 easily over calls to the inferior. Values assigned to internal 137 variables or put into the value history are taken off this 138 list. */ 139 struct value *next; 140 141 /* Register number if the value is from a register. */ 142 short regno; 143 144 /* If zero, contents of this value are in the contents field. If 145 nonzero, contents are in inferior memory at address in the 146 location.address field plus the offset field (and the lval 147 field should be lval_memory). 148 149 WARNING: This field is used by the code which handles 150 watchpoints (see breakpoint.c) to decide whether a particular 151 value can be watched by hardware watchpoints. If the lazy flag 152 is set for some member of a value chain, it is assumed that 153 this member of the chain doesn't need to be watched as part of 154 watching the value itself. This is how GDB avoids watching the 155 entire struct or array when the user wants to watch a single 156 struct member or array element. If you ever change the way 157 lazy flag is set and reset, be sure to consider this use as 158 well! */ 159 char lazy; 160 161 /* If nonzero, this is the value of a variable which does not 162 actually exist in the program. */ 163 char optimized_out; 164 165 /* The BFD section associated with this value. */ 166 asection *bfd_section; 167 168 /* If value is a variable, is it initialized or not. */ 169 int initialized; 170 171 /* Actual contents of the value. For use of this value; setting 172 it uses the stuff above. Not valid if lazy is nonzero. 173 Target byte-order. We force it to be aligned properly for any 174 possible value. Note that a value therefore extends beyond 175 what is declared here. */ 176 union 177 { 178 long contents[1]; 179 DOUBLEST force_doublest_align; 180 LONGEST force_longest_align; 181 CORE_ADDR force_core_addr_align; 182 void *force_pointer_align; 183 } aligner; 184 /* Do not add any new members here -- contents above will trash them. */ 185 }; 186 187 #define VALUE_TYPE(val) (val)->type 188 #define VALUE_ENCLOSING_TYPE(val) (val)->enclosing_type 189 #define VALUE_LAZY(val) (val)->lazy 190 191 /* VALUE_CONTENTS and VALUE_CONTENTS_RAW both return the address of 192 the gdb buffer used to hold a copy of the contents of the lval. 193 VALUE_CONTENTS is used when the contents of the buffer are needed 194 -- it uses value_fetch_lazy() to load the buffer from the process 195 being debugged if it hasn't already been loaded. 196 VALUE_CONTENTS_RAW is used when data is being stored into the 197 buffer, or when it is certain that the contents of the buffer are 198 valid. 199 200 Note: The contents pointer is adjusted by the offset required to 201 get to the real subobject, if the value happens to represent 202 something embedded in a larger run-time object. */ 203 204 #define VALUE_CONTENTS_RAW(val) \ 205 ((char *) (val)->aligner.contents + (val)->embedded_offset) 206 #define VALUE_CONTENTS(val) \ 207 ((void)(VALUE_LAZY(val) && value_fetch_lazy(val)), VALUE_CONTENTS_RAW(val)) 208 209 /* The ALL variants of the above two macros do not adjust the returned 210 pointer by the embedded_offset value. */ 211 212 #define VALUE_CONTENTS_ALL_RAW(val) ((char *) (val)->aligner.contents) 213 #define VALUE_CONTENTS_ALL(val) \ 214 ((void) (VALUE_LAZY(val) && value_fetch_lazy(val)), \ 215 VALUE_CONTENTS_ALL_RAW(val)) 216 217 extern int value_fetch_lazy (struct value *val); 218 219 #define VALUE_LVAL(val) (val)->lval 220 #define VALUE_ADDRESS(val) (val)->location.address 221 #define VALUE_INTERNALVAR(val) (val)->location.internalvar 222 #define VALUE_FRAME_REGNUM(val) ((val)->location.regnum) 223 #define VALUE_FRAME_ID(val) ((val)->frame_id) 224 #define VALUE_OFFSET(val) (val)->offset 225 #define VALUE_BITSIZE(val) (val)->bitsize 226 #define VALUE_BITPOS(val) (val)->bitpos 227 #define VALUE_NEXT(val) (val)->next 228 #define VALUE_REGNO(val) (val)->regno 229 #define VALUE_OPTIMIZED_OUT(val) ((val)->optimized_out) 230 #define VALUE_EMBEDDED_OFFSET(val) ((val)->embedded_offset) 231 #define VALUE_POINTED_TO_OFFSET(val) ((val)->pointed_to_offset) 232 #define VALUE_BFD_SECTION(val) ((val)->bfd_section) 233 234 /* Convert a REF to the object referenced. */ 235 236 #define COERCE_REF(arg) \ 237 do { \ 238 struct type *value_type_arg_tmp = check_typedef (VALUE_TYPE (arg)); \ 239 if (TYPE_CODE (value_type_arg_tmp) == TYPE_CODE_REF) \ 240 arg = value_at_lazy (TYPE_TARGET_TYPE (value_type_arg_tmp), \ 241 unpack_pointer (VALUE_TYPE (arg), \ 242 VALUE_CONTENTS (arg)), \ 243 VALUE_BFD_SECTION (arg)); \ 244 } while (0) 245 246 /* If ARG is an array, convert it to a pointer. 247 If ARG is an enum, convert it to an integer. 248 If ARG is a function, convert it to a function pointer. 249 250 References are dereferenced. */ 251 252 #define COERCE_ARRAY(arg) \ 253 do { \ 254 COERCE_REF(arg); \ 255 if (current_language->c_style_arrays \ 256 && TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_ARRAY) \ 257 arg = value_coerce_array (arg); \ 258 if (TYPE_CODE (VALUE_TYPE (arg)) == TYPE_CODE_FUNC) \ 259 arg = value_coerce_function (arg); \ 260 } while (0) 261 262 #define COERCE_NUMBER(arg) \ 263 do { COERCE_ARRAY(arg); COERCE_ENUM(arg); } while (0) 264 265 /* NOTE: cagney/2002-12-17: This macro was handling a chill language 266 problem but that language has gone away. */ 267 #define COERCE_VARYING_ARRAY(arg, real_arg_type) 268 269 /* If ARG is an enum, convert it to an integer. */ 270 271 #define COERCE_ENUM(arg) \ 272 do { \ 273 if (TYPE_CODE (check_typedef (VALUE_TYPE (arg))) == TYPE_CODE_ENUM) \ 274 arg = value_cast (builtin_type_unsigned_int, arg); \ 275 } while (0) 276 277 /* Internal variables (variables for convenience of use of debugger) 278 are recorded as a chain of these structures. */ 279 280 struct internalvar 281 { 282 struct internalvar *next; 283 char *name; 284 struct value *value; 285 }; 286 287 /* Pointer to member function. Depends on compiler implementation. */ 288 289 #define METHOD_PTR_IS_VIRTUAL(ADDR) ((ADDR) & 0x80000000) 290 #define METHOD_PTR_FROM_VOFFSET(OFFSET) (0x80000000 + (OFFSET)) 291 #define METHOD_PTR_TO_VOFFSET(ADDR) (~0x80000000 & (ADDR)) 292 293 294 #include "symtab.h" 295 #include "gdbtypes.h" 296 #include "expression.h" 297 298 struct frame_info; 299 struct fn_field; 300 301 extern void print_address_demangle (CORE_ADDR, struct ui_file *, int); 302 303 extern LONGEST value_as_long (struct value *val); 304 extern DOUBLEST value_as_double (struct value *val); 305 extern CORE_ADDR value_as_address (struct value *val); 306 307 extern LONGEST unpack_long (struct type *type, const char *valaddr); 308 extern DOUBLEST unpack_double (struct type *type, const char *valaddr, 309 int *invp); 310 extern CORE_ADDR unpack_pointer (struct type *type, const char *valaddr); 311 extern LONGEST unpack_field_as_long (struct type *type, const char *valaddr, 312 int fieldno); 313 314 extern struct value *value_from_longest (struct type *type, LONGEST num); 315 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr); 316 extern struct value *value_from_double (struct type *type, DOUBLEST num); 317 extern struct value *value_from_string (char *string); 318 319 extern struct value *value_at (struct type *type, CORE_ADDR addr, 320 asection * sect); 321 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr, 322 asection * sect); 323 324 extern struct value *value_from_register (struct type *type, int regnum, 325 struct frame_info *frame); 326 327 extern struct value *value_of_variable (struct symbol *var, struct block *b); 328 329 extern struct value *value_of_register (int regnum, 330 struct frame_info *frame); 331 332 extern int symbol_read_needs_frame (struct symbol *); 333 334 extern struct value *read_var_value (struct symbol *var, 335 struct frame_info *frame); 336 337 extern struct value *locate_var_value (struct symbol *var, 338 struct frame_info *frame); 339 340 extern struct value *allocate_value (struct type *type); 341 342 extern struct value *allocate_repeat_value (struct type *type, int count); 343 344 extern struct value *value_change_enclosing_type (struct value *val, 345 struct type *new_type); 346 347 extern struct value *value_mark (void); 348 349 extern void value_free_to_mark (struct value *mark); 350 351 extern struct value *value_string (char *ptr, int len); 352 extern struct value *value_bitstring (char *ptr, int len); 353 354 extern struct value *value_array (int lowbound, int highbound, 355 struct value ** elemvec); 356 357 extern struct value *value_concat (struct value *arg1, struct value *arg2); 358 359 extern struct value *value_binop (struct value *arg1, struct value *arg2, 360 enum exp_opcode op); 361 362 extern struct value *value_add (struct value *arg1, struct value *arg2); 363 364 extern struct value *value_sub (struct value *arg1, struct value *arg2); 365 366 extern struct value *value_coerce_array (struct value *arg1); 367 368 extern struct value *value_coerce_function (struct value *arg1); 369 370 extern struct value *value_ind (struct value *arg1); 371 372 extern struct value *value_addr (struct value *arg1); 373 374 extern struct value *value_assign (struct value *toval, struct value *fromval); 375 376 extern struct value *value_neg (struct value *arg1); 377 378 extern struct value *value_complement (struct value *arg1); 379 380 extern struct value *value_struct_elt (struct value **argp, 381 struct value **args, 382 char *name, int *static_memfuncp, 383 char *err); 384 385 extern struct value *value_aggregate_elt (struct type *curtype, 386 char *name, 387 enum noside noside); 388 389 extern struct value *value_static_field (struct type *type, int fieldno); 390 391 extern struct fn_field *value_find_oload_method_list (struct value **, char *, 392 int, int *, 393 struct type **, int *); 394 395 extern int find_overload_match (struct type **arg_types, int nargs, 396 char *name, int method, int lax, 397 struct value **objp, struct symbol *fsym, 398 struct value **valp, struct symbol **symp, 399 int *staticp); 400 401 extern struct value *value_field (struct value *arg1, int fieldno); 402 403 extern struct value *value_primitive_field (struct value *arg1, int offset, 404 int fieldno, 405 struct type *arg_type); 406 407 408 extern struct type *value_rtti_target_type (struct value *, int *, int *, 409 int *); 410 411 extern struct value *value_full_object (struct value *, struct type *, int, 412 int, int); 413 414 extern struct value *value_cast (struct type *type, struct value *arg2); 415 416 extern struct value *value_zero (struct type *type, enum lval_type lv); 417 418 extern struct value *value_repeat (struct value *arg1, int count); 419 420 extern struct value *value_subscript (struct value *array, struct value *idx); 421 422 extern struct value *register_value_being_returned (struct type *valtype, 423 struct regcache *retbuf); 424 425 extern struct value *value_in (struct value *element, struct value *set); 426 427 extern int value_bit_index (struct type *type, char *addr, int index); 428 429 extern int using_struct_return (struct type *value_type, int gcc_p); 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 modify_field (char *addr, LONGEST fieldval, int bitpos, 500 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 common_val_print (struct value *val, 530 struct ui_file *stream, int format, 531 int deref_ref, int recurse, 532 enum val_prettyprint pretty); 533 534 extern int val_print_string (CORE_ADDR addr, int len, int width, struct ui_file *stream); 535 536 extern void print_variable_value (struct symbol * var, 537 struct frame_info * frame, 538 struct ui_file *stream); 539 540 extern int check_field (struct value *, const char *); 541 542 extern void typedef_print (struct type * type, struct symbol * news, 543 struct ui_file * stream); 544 545 extern char *internalvar_name (struct internalvar *var); 546 547 extern void clear_value_history (void); 548 549 extern void clear_internalvars (void); 550 551 /* From values.c */ 552 553 extern struct value *value_copy (struct value *); 554 555 /* From valops.c */ 556 557 extern struct value *varying_to_slice (struct value *); 558 559 extern struct value *value_slice (struct value *, int, int); 560 561 extern struct value *value_literal_complex (struct value *, struct value *, 562 struct type *); 563 564 extern void find_rt_vbase_offset (struct type *, struct type *, char *, int, 565 int *, int *); 566 567 extern struct value *find_function_in_inferior (const char *); 568 569 extern struct value *value_allocate_space_in_inferior (int); 570 571 extern CORE_ADDR legacy_push_arguments (int nargs, struct value ** args, 572 CORE_ADDR sp, int struct_return, 573 CORE_ADDR struct_addr); 574 575 extern struct value *value_of_local (const char *name, int complain); 576 577 #endif /* !defined (VALUE_H) */ 578