1 /* Definitions for values of C expressions, for GDB. 2 3 Copyright (C) 1986-2020 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #if !defined (VALUE_H) 21 #define VALUE_H 1 22 23 #include "frame.h" /* For struct frame_id. */ 24 #include "extension.h" 25 #include "gdbsupport/gdb_ref_ptr.h" 26 27 struct block; 28 struct expression; 29 struct regcache; 30 struct symbol; 31 struct type; 32 struct ui_file; 33 struct language_defn; 34 struct value_print_options; 35 36 /* Values can be partially 'optimized out' and/or 'unavailable'. 37 These are distinct states and have different string representations 38 and related error strings. 39 40 'unavailable' has a specific meaning in this context. It means the 41 value exists in the program (at the machine level), but GDB has no 42 means to get to it. Such a value is normally printed as 43 <unavailable>. Examples of how to end up with an unavailable value 44 would be: 45 46 - We're inspecting a traceframe, and the memory or registers the 47 debug information says the value lives on haven't been collected. 48 49 - We're inspecting a core dump, the memory or registers the debug 50 information says the value lives aren't present in the dump 51 (that is, we have a partial/trimmed core dump, or we don't fully 52 understand/handle the core dump's format). 53 54 - We're doing live debugging, but the debug API has no means to 55 get at where the value lives in the machine, like e.g., ptrace 56 not having access to some register or register set. 57 58 - Any other similar scenario. 59 60 OTOH, "optimized out" is about what the compiler decided to generate 61 (or not generate). A chunk of a value that was optimized out does 62 not actually exist in the program. There's no way to get at it 63 short of compiling the program differently. 64 65 A register that has not been saved in a frame is likewise considered 66 optimized out, except not-saved registers have a different string 67 representation and related error strings. E.g., we'll print them as 68 <not-saved> instead of <optimized out>, as in: 69 70 (gdb) p/x $rax 71 $1 = <not saved> 72 (gdb) info registers rax 73 rax <not saved> 74 75 If the debug info describes a variable as being in such a register, 76 we'll still print the variable as <optimized out>. IOW, <not saved> 77 is reserved for inspecting registers at the machine level. 78 79 When comparing value contents, optimized out chunks, unavailable 80 chunks, and valid contents data are all considered different. See 81 value_contents_eq for more info. 82 */ 83 84 extern bool overload_resolution; 85 86 /* The structure which defines the type of a value. It should never 87 be possible for a program lval value to survive over a call to the 88 inferior (i.e. to be put into the history list or an internal 89 variable). */ 90 91 struct value; 92 93 /* Increase VAL's reference count. */ 94 95 extern void value_incref (struct value *val); 96 97 /* Decrease VAL's reference count. When the reference count drops to 98 0, VAL will be freed. */ 99 100 extern void value_decref (struct value *val); 101 102 /* A policy class to interface gdb::ref_ptr with struct value. */ 103 104 struct value_ref_policy 105 { 106 static void incref (struct value *ptr) 107 { 108 value_incref (ptr); 109 } 110 111 static void decref (struct value *ptr) 112 { 113 value_decref (ptr); 114 } 115 }; 116 117 /* A gdb:;ref_ptr pointer to a struct value. */ 118 119 typedef gdb::ref_ptr<struct value, value_ref_policy> value_ref_ptr; 120 121 /* Values are stored in a chain, so that they can be deleted easily 122 over calls to the inferior. Values assigned to internal variables, 123 put into the value history or exposed to Python are taken off this 124 list. */ 125 126 struct value *value_next (const struct value *); 127 128 /* Type of the value. */ 129 130 extern struct type *value_type (const struct value *); 131 132 /* Return the gdbarch associated with the value. */ 133 134 extern struct gdbarch *get_value_arch (const struct value *value); 135 136 /* This is being used to change the type of an existing value, that 137 code should instead be creating a new value with the changed type 138 (but possibly shared content). */ 139 140 extern void deprecated_set_value_type (struct value *value, 141 struct type *type); 142 143 /* Only used for bitfields; number of bits contained in them. */ 144 145 extern LONGEST value_bitsize (const struct value *); 146 extern void set_value_bitsize (struct value *, LONGEST bit); 147 148 /* Only used for bitfields; position of start of field. For 149 little-endian targets, it is the position of the LSB. For 150 big-endian targets, it is the position of the MSB. */ 151 152 extern LONGEST value_bitpos (const struct value *); 153 extern void set_value_bitpos (struct value *, LONGEST bit); 154 155 /* Only used for bitfields; the containing value. This allows a 156 single read from the target when displaying multiple 157 bitfields. */ 158 159 struct value *value_parent (const struct value *); 160 extern void set_value_parent (struct value *value, struct value *parent); 161 162 /* Describes offset of a value within lval of a structure in bytes. 163 If lval == lval_memory, this is an offset to the address. If lval 164 == lval_register, this is a further offset from location.address 165 within the registers structure. Note also the member 166 embedded_offset below. */ 167 168 extern LONGEST value_offset (const struct value *); 169 extern void set_value_offset (struct value *, LONGEST offset); 170 171 /* The comment from "struct value" reads: ``Is it modifiable? Only 172 relevant if lval != not_lval.''. Shouldn't the value instead be 173 not_lval and be done with it? */ 174 175 extern int deprecated_value_modifiable (const struct value *value); 176 177 /* If a value represents a C++ object, then the `type' field gives the 178 object's compile-time type. If the object actually belongs to some 179 class derived from `type', perhaps with other base classes and 180 additional members, then `type' is just a subobject of the real 181 thing, and the full object is probably larger than `type' would 182 suggest. 183 184 If `type' is a dynamic class (i.e. one with a vtable), then GDB can 185 actually determine the object's run-time type by looking at the 186 run-time type information in the vtable. When this information is 187 available, we may elect to read in the entire object, for several 188 reasons: 189 190 - When printing the value, the user would probably rather see the 191 full object, not just the limited portion apparent from the 192 compile-time type. 193 194 - If `type' has virtual base classes, then even printing `type' 195 alone may require reaching outside the `type' portion of the 196 object to wherever the virtual base class has been stored. 197 198 When we store the entire object, `enclosing_type' is the run-time 199 type -- the complete object -- and `embedded_offset' is the offset 200 of `type' within that larger type, in bytes. The value_contents() 201 macro takes `embedded_offset' into account, so most GDB code 202 continues to see the `type' portion of the value, just as the 203 inferior would. 204 205 If `type' is a pointer to an object, then `enclosing_type' is a 206 pointer to the object's run-time type, and `pointed_to_offset' is 207 the offset in bytes from the full object to the pointed-to object 208 -- that is, the value `embedded_offset' would have if we followed 209 the pointer and fetched the complete object. (I don't really see 210 the point. Why not just determine the run-time type when you 211 indirect, and avoid the special case? The contents don't matter 212 until you indirect anyway.) 213 214 If we're not doing anything fancy, `enclosing_type' is equal to 215 `type', and `embedded_offset' is zero, so everything works 216 normally. */ 217 218 extern struct type *value_enclosing_type (const struct value *); 219 extern void set_value_enclosing_type (struct value *val, 220 struct type *new_type); 221 222 /* Returns value_type or value_enclosing_type depending on 223 value_print_options.objectprint. 224 225 If RESOLVE_SIMPLE_TYPES is 0 the enclosing type will be resolved 226 only for pointers and references, else it will be returned 227 for all the types (e.g. structures). This option is useful 228 to prevent retrieving enclosing type for the base classes fields. 229 230 REAL_TYPE_FOUND is used to inform whether the real type was found 231 (or just static type was used). The NULL may be passed if it is not 232 necessary. */ 233 234 extern struct type *value_actual_type (struct value *value, 235 int resolve_simple_types, 236 int *real_type_found); 237 238 extern LONGEST value_pointed_to_offset (const struct value *value); 239 extern void set_value_pointed_to_offset (struct value *value, LONGEST val); 240 extern LONGEST value_embedded_offset (const struct value *value); 241 extern void set_value_embedded_offset (struct value *value, LONGEST val); 242 243 /* For lval_computed values, this structure holds functions used to 244 retrieve and set the value (or portions of the value). 245 246 For each function, 'V' is the 'this' pointer: an lval_funcs 247 function F may always assume that the V it receives is an 248 lval_computed value, and has F in the appropriate slot of its 249 lval_funcs structure. */ 250 251 struct lval_funcs 252 { 253 /* Fill in VALUE's contents. This is used to "un-lazy" values. If 254 a problem arises in obtaining VALUE's bits, this function should 255 call 'error'. If it is NULL value_fetch_lazy on "un-lazy" 256 non-optimized-out value is an internal error. */ 257 void (*read) (struct value *v); 258 259 /* Handle an assignment TOVAL = FROMVAL by writing the value of 260 FROMVAL to TOVAL's location. The contents of TOVAL have not yet 261 been updated. If a problem arises in doing so, this function 262 should call 'error'. If it is NULL such TOVAL assignment is an error as 263 TOVAL is not considered as an lvalue. */ 264 void (*write) (struct value *toval, struct value *fromval); 265 266 /* If non-NULL, this is used to implement pointer indirection for 267 this value. This method may return NULL, in which case value_ind 268 will fall back to ordinary indirection. */ 269 struct value *(*indirect) (struct value *value); 270 271 /* If non-NULL, this is used to implement reference resolving for 272 this value. This method may return NULL, in which case coerce_ref 273 will fall back to ordinary references resolving. */ 274 struct value *(*coerce_ref) (const struct value *value); 275 276 /* If non-NULL, this is used to determine whether the indicated bits 277 of VALUE are a synthetic pointer. */ 278 int (*check_synthetic_pointer) (const struct value *value, 279 LONGEST offset, int length); 280 281 /* Return a duplicate of VALUE's closure, for use in a new value. 282 This may simply return the same closure, if VALUE's is 283 reference-counted or statically allocated. 284 285 This may be NULL, in which case VALUE's closure is re-used in the 286 new value. */ 287 void *(*copy_closure) (const struct value *v); 288 289 /* Drop VALUE's reference to its closure. Maybe this frees the 290 closure; maybe this decrements a reference count; maybe the 291 closure is statically allocated and this does nothing. 292 293 This may be NULL, in which case no action is taken to free 294 VALUE's closure. */ 295 void (*free_closure) (struct value *v); 296 }; 297 298 /* Create a computed lvalue, with type TYPE, function pointers FUNCS, 299 and closure CLOSURE. */ 300 301 extern struct value *allocate_computed_value (struct type *type, 302 const struct lval_funcs *funcs, 303 void *closure); 304 305 extern struct value *allocate_optimized_out_value (struct type *type); 306 307 /* If VALUE is lval_computed, return its lval_funcs structure. */ 308 309 extern const struct lval_funcs *value_computed_funcs (const struct value *); 310 311 /* If VALUE is lval_computed, return its closure. The meaning of the 312 returned value depends on the functions VALUE uses. */ 313 314 extern void *value_computed_closure (const struct value *value); 315 316 /* If zero, contents of this value are in the contents field. If 317 nonzero, contents are in inferior. If the lval field is lval_memory, 318 the contents are in inferior memory at location.address plus offset. 319 The lval field may also be lval_register. 320 321 WARNING: This field is used by the code which handles watchpoints 322 (see breakpoint.c) to decide whether a particular value can be 323 watched by hardware watchpoints. If the lazy flag is set for some 324 member of a value chain, it is assumed that this member of the 325 chain doesn't need to be watched as part of watching the value 326 itself. This is how GDB avoids watching the entire struct or array 327 when the user wants to watch a single struct member or array 328 element. If you ever change the way lazy flag is set and reset, be 329 sure to consider this use as well! */ 330 331 extern int value_lazy (const struct value *); 332 extern void set_value_lazy (struct value *value, int val); 333 334 extern int value_stack (const struct value *); 335 extern void set_value_stack (struct value *value, int val); 336 337 /* Throw an error complaining that the value has been optimized 338 out. */ 339 340 extern void error_value_optimized_out (void); 341 342 /* value_contents() and value_contents_raw() both return the address 343 of the gdb buffer used to hold a copy of the contents of the lval. 344 value_contents() is used when the contents of the buffer are needed 345 -- it uses value_fetch_lazy() to load the buffer from the process 346 being debugged if it hasn't already been loaded 347 (value_contents_writeable() is used when a writeable but fetched 348 buffer is required).. value_contents_raw() is used when data is 349 being stored into the buffer, or when it is certain that the 350 contents of the buffer are valid. 351 352 Note: The contents pointer is adjusted by the offset required to 353 get to the real subobject, if the value happens to represent 354 something embedded in a larger run-time object. */ 355 356 extern gdb_byte *value_contents_raw (struct value *); 357 358 /* Actual contents of the value. For use of this value; setting it 359 uses the stuff above. Not valid if lazy is nonzero. Target 360 byte-order. We force it to be aligned properly for any possible 361 value. Note that a value therefore extends beyond what is 362 declared here. */ 363 364 extern const gdb_byte *value_contents (struct value *); 365 extern gdb_byte *value_contents_writeable (struct value *); 366 367 /* The ALL variants of the above two macros do not adjust the returned 368 pointer by the embedded_offset value. */ 369 370 extern gdb_byte *value_contents_all_raw (struct value *); 371 extern const gdb_byte *value_contents_all (struct value *); 372 373 /* Like value_contents_all, but does not require that the returned 374 bits be valid. This should only be used in situations where you 375 plan to check the validity manually. */ 376 extern const gdb_byte *value_contents_for_printing (struct value *value); 377 378 /* Like value_contents_for_printing, but accepts a constant value 379 pointer. Unlike value_contents_for_printing however, the pointed 380 value must _not_ be lazy. */ 381 extern const gdb_byte * 382 value_contents_for_printing_const (const struct value *value); 383 384 extern void value_fetch_lazy (struct value *val); 385 386 /* If nonzero, this is the value of a variable which does not actually 387 exist in the program, at least partially. If the value is lazy, 388 this may fetch it now. */ 389 extern int value_optimized_out (struct value *value); 390 391 /* Given a value, return true if any of the contents bits starting at 392 OFFSET and extending for LENGTH bits is optimized out, false 393 otherwise. */ 394 395 extern int value_bits_any_optimized_out (const struct value *value, 396 int bit_offset, int bit_length); 397 398 /* Like value_optimized_out, but return true iff the whole value is 399 optimized out. */ 400 extern int value_entirely_optimized_out (struct value *value); 401 402 /* Mark VALUE's content bytes starting at OFFSET and extending for 403 LENGTH bytes as optimized out. */ 404 405 extern void mark_value_bytes_optimized_out (struct value *value, 406 int offset, int length); 407 408 /* Mark VALUE's content bits starting at OFFSET and extending for 409 LENGTH bits as optimized out. */ 410 411 extern void mark_value_bits_optimized_out (struct value *value, 412 LONGEST offset, LONGEST length); 413 414 /* Set or return field indicating whether a variable is initialized or 415 not, based on debugging information supplied by the compiler. 416 1 = initialized; 0 = uninitialized. */ 417 extern int value_initialized (const struct value *); 418 extern void set_value_initialized (struct value *, int); 419 420 /* Set COMPONENT's location as appropriate for a component of WHOLE 421 --- regardless of what kind of lvalue WHOLE is. */ 422 extern void set_value_component_location (struct value *component, 423 const struct value *whole); 424 425 /* While the following fields are per- VALUE .CONTENT .PIECE (i.e., a 426 single value might have multiple LVALs), this hacked interface is 427 limited to just the first PIECE. Expect further change. */ 428 /* Type of value; either not an lval, or one of the various different 429 possible kinds of lval. */ 430 extern enum lval_type *deprecated_value_lval_hack (struct value *); 431 #define VALUE_LVAL(val) (*deprecated_value_lval_hack (val)) 432 433 /* Like VALUE_LVAL, except the parameter can be const. */ 434 extern enum lval_type value_lval_const (const struct value *value); 435 436 /* If lval == lval_memory, return the address in the inferior. If 437 lval == lval_register, return the byte offset into the registers 438 structure. Otherwise, return 0. The returned address 439 includes the offset, if any. */ 440 extern CORE_ADDR value_address (const struct value *); 441 442 /* Like value_address, except the result does not include value's 443 offset. */ 444 extern CORE_ADDR value_raw_address (const struct value *); 445 446 /* Set the address of a value. */ 447 extern void set_value_address (struct value *, CORE_ADDR); 448 449 /* Pointer to internal variable. */ 450 extern struct internalvar **deprecated_value_internalvar_hack (struct value *); 451 #define VALUE_INTERNALVAR(val) (*deprecated_value_internalvar_hack (val)) 452 453 /* Frame ID of "next" frame to which a register value is relative. A 454 register value is indicated by VALUE_LVAL being set to lval_register. 455 So, if the register value is found relative to frame F, then the 456 frame id of F->next will be stored in VALUE_NEXT_FRAME_ID. */ 457 extern struct frame_id *deprecated_value_next_frame_id_hack (struct value *); 458 #define VALUE_NEXT_FRAME_ID(val) (*deprecated_value_next_frame_id_hack (val)) 459 460 /* Frame ID of frame to which a register value is relative. This is 461 similar to VALUE_NEXT_FRAME_ID, above, but may not be assigned to. 462 Note that VALUE_FRAME_ID effectively undoes the "next" operation 463 that was performed during the assignment to VALUE_NEXT_FRAME_ID. */ 464 #define VALUE_FRAME_ID(val) (get_prev_frame_id_by_id (VALUE_NEXT_FRAME_ID (val))) 465 466 /* Register number if the value is from a register. */ 467 extern int *deprecated_value_regnum_hack (struct value *); 468 #define VALUE_REGNUM(val) (*deprecated_value_regnum_hack (val)) 469 470 /* Return value after lval_funcs->coerce_ref (after check_typedef). Return 471 NULL if lval_funcs->coerce_ref is not applicable for whatever reason. */ 472 473 extern struct value *coerce_ref_if_computed (const struct value *arg); 474 475 /* Setup a new value type and enclosing value type for dereferenced value VALUE. 476 ENC_TYPE is the new enclosing type that should be set. ORIGINAL_TYPE and 477 ORIGINAL_VAL are the type and value of the original reference or 478 pointer. ORIGINAL_VALUE_ADDRESS is the address within VALUE, that is 479 the address that was dereferenced. 480 481 Note, that VALUE is modified by this function. 482 483 It is a common implementation for coerce_ref and value_ind. */ 484 485 extern struct value * readjust_indirect_value_type (struct value *value, 486 struct type *enc_type, 487 const struct type *original_type, 488 struct value *original_val, 489 CORE_ADDR original_value_address); 490 491 /* Convert a REF to the object referenced. */ 492 493 extern struct value *coerce_ref (struct value *value); 494 495 /* If ARG is an array, convert it to a pointer. 496 If ARG is a function, convert it to a function pointer. 497 498 References are dereferenced. */ 499 500 extern struct value *coerce_array (struct value *value); 501 502 /* Given a value, determine whether the bits starting at OFFSET and 503 extending for LENGTH bits are a synthetic pointer. */ 504 505 extern int value_bits_synthetic_pointer (const struct value *value, 506 LONGEST offset, LONGEST length); 507 508 /* Given a value, determine whether the contents bytes starting at 509 OFFSET and extending for LENGTH bytes are available. This returns 510 nonzero if all bytes in the given range are available, zero if any 511 byte is unavailable. */ 512 513 extern int value_bytes_available (const struct value *value, 514 LONGEST offset, LONGEST length); 515 516 /* Given a value, determine whether the contents bits starting at 517 OFFSET and extending for LENGTH bits are available. This returns 518 nonzero if all bits in the given range are available, zero if any 519 bit is unavailable. */ 520 521 extern int value_bits_available (const struct value *value, 522 LONGEST offset, LONGEST length); 523 524 /* Like value_bytes_available, but return false if any byte in the 525 whole object is unavailable. */ 526 extern int value_entirely_available (struct value *value); 527 528 /* Like value_entirely_available, but return false if any byte in the 529 whole object is available. */ 530 extern int value_entirely_unavailable (struct value *value); 531 532 /* Mark VALUE's content bytes starting at OFFSET and extending for 533 LENGTH bytes as unavailable. */ 534 535 extern void mark_value_bytes_unavailable (struct value *value, 536 LONGEST offset, LONGEST length); 537 538 /* Mark VALUE's content bits starting at OFFSET and extending for 539 LENGTH bits as unavailable. */ 540 541 extern void mark_value_bits_unavailable (struct value *value, 542 LONGEST offset, LONGEST length); 543 544 /* Compare LENGTH bytes of VAL1's contents starting at OFFSET1 with 545 LENGTH bytes of VAL2's contents starting at OFFSET2. 546 547 Note that "contents" refers to the whole value's contents 548 (value_contents_all), without any embedded offset adjustment. For 549 example, to compare a complete object value with itself, including 550 its enclosing type chunk, you'd do: 551 552 int len = TYPE_LENGTH (check_typedef (value_enclosing_type (val))); 553 value_contents_eq (val, 0, val, 0, len); 554 555 Returns true iff the set of available/valid contents match. 556 557 Optimized-out contents are equal to optimized-out contents, and are 558 not equal to non-optimized-out contents. 559 560 Unavailable contents are equal to unavailable contents, and are not 561 equal to non-unavailable contents. 562 563 For example, if 'x's represent an unavailable byte, and 'V' and 'Z' 564 represent different available/valid bytes, in a value with length 565 16: 566 567 offset: 0 4 8 12 16 568 contents: xxxxVVVVxxxxVVZZ 569 570 then: 571 572 value_contents_eq(val, 0, val, 8, 6) => true 573 value_contents_eq(val, 0, val, 4, 4) => false 574 value_contents_eq(val, 0, val, 8, 8) => false 575 value_contents_eq(val, 4, val, 12, 2) => true 576 value_contents_eq(val, 4, val, 12, 4) => true 577 value_contents_eq(val, 3, val, 4, 4) => true 578 579 If 'x's represent an unavailable byte, 'o' represents an optimized 580 out byte, in a value with length 8: 581 582 offset: 0 4 8 583 contents: xxxxoooo 584 585 then: 586 587 value_contents_eq(val, 0, val, 2, 2) => true 588 value_contents_eq(val, 4, val, 6, 2) => true 589 value_contents_eq(val, 0, val, 4, 4) => true 590 591 We only know whether a value chunk is unavailable or optimized out 592 if we've tried to read it. As this routine is used by printing 593 routines, which may be printing values in the value history, long 594 after the inferior is gone, it works with const values. Therefore, 595 this routine must not be called with lazy values. */ 596 597 extern bool value_contents_eq (const struct value *val1, LONGEST offset1, 598 const struct value *val2, LONGEST offset2, 599 LONGEST length); 600 601 /* Read LENGTH addressable memory units starting at MEMADDR into BUFFER, 602 which is (or will be copied to) VAL's contents buffer offset by 603 BIT_OFFSET bits. Marks value contents ranges as unavailable if 604 the corresponding memory is likewise unavailable. STACK indicates 605 whether the memory is known to be stack memory. */ 606 607 extern void read_value_memory (struct value *val, LONGEST bit_offset, 608 int stack, CORE_ADDR memaddr, 609 gdb_byte *buffer, size_t length); 610 611 /* Cast SCALAR_VALUE to the element type of VECTOR_TYPE, then replicate 612 into each element of a new vector value with VECTOR_TYPE. */ 613 614 struct value *value_vector_widen (struct value *scalar_value, 615 struct type *vector_type); 616 617 618 619 #include "symtab.h" 620 #include "gdbtypes.h" 621 #include "expression.h" 622 623 struct frame_info; 624 struct fn_field; 625 626 extern int print_address_demangle (const struct value_print_options *, 627 struct gdbarch *, CORE_ADDR, 628 struct ui_file *, int); 629 630 /* Returns true if VAL is of floating-point type. In addition, 631 throws an error if the value is an invalid floating-point value. */ 632 extern bool is_floating_value (struct value *val); 633 634 extern LONGEST value_as_long (struct value *val); 635 extern CORE_ADDR value_as_address (struct value *val); 636 637 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr); 638 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr); 639 640 extern LONGEST unpack_field_as_long (struct type *type, 641 const gdb_byte *valaddr, 642 int fieldno); 643 644 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at 645 VALADDR, and store the result in *RESULT. 646 The bitfield starts at BITPOS bits and contains BITSIZE bits; if 647 BITSIZE is zero, then the length is taken from FIELD_TYPE. 648 649 Extracting bits depends on endianness of the machine. Compute the 650 number of least significant bits to discard. For big endian machines, 651 we compute the total number of bits in the anonymous object, subtract 652 off the bit count from the MSB of the object to the MSB of the 653 bitfield, then the size of the bitfield, which leaves the LSB discard 654 count. For little endian machines, the discard count is simply the 655 number of bits from the LSB of the anonymous object to the LSB of the 656 bitfield. 657 658 If the field is signed, we also do sign extension. */ 659 660 extern LONGEST unpack_bits_as_long (struct type *field_type, 661 const gdb_byte *valaddr, 662 LONGEST bitpos, LONGEST bitsize); 663 664 extern int unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr, 665 LONGEST embedded_offset, int fieldno, 666 const struct value *val, LONGEST *result); 667 668 extern void unpack_value_bitfield (struct value *dest_val, 669 LONGEST bitpos, LONGEST bitsize, 670 const gdb_byte *valaddr, 671 LONGEST embedded_offset, 672 const struct value *val); 673 674 extern struct value *value_field_bitfield (struct type *type, int fieldno, 675 const gdb_byte *valaddr, 676 LONGEST embedded_offset, 677 const struct value *val); 678 679 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num); 680 681 extern struct value *value_from_longest (struct type *type, LONGEST num); 682 extern struct value *value_from_ulongest (struct type *type, ULONGEST num); 683 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr); 684 extern struct value *value_from_host_double (struct type *type, double d); 685 extern struct value *value_from_history_ref (const char *, const char **); 686 extern struct value *value_from_component (struct value *, struct type *, 687 LONGEST); 688 689 extern struct value *value_at (struct type *type, CORE_ADDR addr); 690 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr); 691 692 extern struct value *value_from_contents_and_address_unresolved 693 (struct type *, const gdb_byte *, CORE_ADDR); 694 extern struct value *value_from_contents_and_address (struct type *, 695 const gdb_byte *, 696 CORE_ADDR); 697 extern struct value *value_from_contents (struct type *, const gdb_byte *); 698 699 extern struct value *default_value_from_register (struct gdbarch *gdbarch, 700 struct type *type, 701 int regnum, 702 struct frame_id frame_id); 703 704 extern void read_frame_register_value (struct value *value, 705 struct frame_info *frame); 706 707 extern struct value *value_from_register (struct type *type, int regnum, 708 struct frame_info *frame); 709 710 extern CORE_ADDR address_from_register (int regnum, 711 struct frame_info *frame); 712 713 extern struct value *value_of_variable (struct symbol *var, 714 const struct block *b); 715 716 extern struct value *address_of_variable (struct symbol *var, 717 const struct block *b); 718 719 extern struct value *value_of_register (int regnum, struct frame_info *frame); 720 721 struct value *value_of_register_lazy (struct frame_info *frame, int regnum); 722 723 /* Return the symbol's reading requirement. */ 724 725 extern enum symbol_needs_kind symbol_read_needs (struct symbol *); 726 727 /* Return true if the symbol needs a frame. This is a wrapper for 728 symbol_read_needs that simply checks for SYMBOL_NEEDS_FRAME. */ 729 730 extern int symbol_read_needs_frame (struct symbol *); 731 732 extern struct value *read_var_value (struct symbol *var, 733 const struct block *var_block, 734 struct frame_info *frame); 735 736 extern struct value *allocate_value (struct type *type); 737 extern struct value *allocate_value_lazy (struct type *type); 738 extern void value_contents_copy (struct value *dst, LONGEST dst_offset, 739 struct value *src, LONGEST src_offset, 740 LONGEST length); 741 extern void value_contents_copy_raw (struct value *dst, LONGEST dst_offset, 742 struct value *src, LONGEST src_offset, 743 LONGEST length); 744 745 extern struct value *allocate_repeat_value (struct type *type, int count); 746 747 extern struct value *value_mark (void); 748 749 extern void value_free_to_mark (const struct value *mark); 750 751 /* A helper class that uses value_mark at construction time and calls 752 value_free_to_mark in the destructor. This is used to clear out 753 temporary values created during the lifetime of this object. */ 754 class scoped_value_mark 755 { 756 public: 757 758 scoped_value_mark () 759 : m_value (value_mark ()) 760 { 761 } 762 763 ~scoped_value_mark () 764 { 765 free_to_mark (); 766 } 767 768 scoped_value_mark (scoped_value_mark &&other) = default; 769 770 DISABLE_COPY_AND_ASSIGN (scoped_value_mark); 771 772 /* Free the values currently on the value stack. */ 773 void free_to_mark () 774 { 775 if (m_value != NULL) 776 { 777 value_free_to_mark (m_value); 778 m_value = NULL; 779 } 780 } 781 782 private: 783 784 const struct value *m_value; 785 }; 786 787 extern struct value *value_cstring (const char *ptr, ssize_t len, 788 struct type *char_type); 789 extern struct value *value_string (const char *ptr, ssize_t len, 790 struct type *char_type); 791 792 extern struct value *value_array (int lowbound, int highbound, 793 struct value **elemvec); 794 795 extern struct value *value_concat (struct value *arg1, struct value *arg2); 796 797 extern struct value *value_binop (struct value *arg1, struct value *arg2, 798 enum exp_opcode op); 799 800 extern struct value *value_ptradd (struct value *arg1, LONGEST arg2); 801 802 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2); 803 804 /* Return true if VAL does not live in target memory, but should in order 805 to operate on it. Otherwise return false. */ 806 807 extern bool value_must_coerce_to_target (struct value *arg1); 808 809 extern struct value *value_coerce_to_target (struct value *arg1); 810 811 extern struct value *value_coerce_array (struct value *arg1); 812 813 extern struct value *value_coerce_function (struct value *arg1); 814 815 extern struct value *value_ind (struct value *arg1); 816 817 extern struct value *value_addr (struct value *arg1); 818 819 extern struct value *value_ref (struct value *arg1, enum type_code refcode); 820 821 extern struct value *value_assign (struct value *toval, 822 struct value *fromval); 823 824 extern struct value *value_pos (struct value *arg1); 825 826 extern struct value *value_neg (struct value *arg1); 827 828 extern struct value *value_complement (struct value *arg1); 829 830 extern struct value *value_struct_elt (struct value **argp, 831 struct value **args, 832 const char *name, int *static_memfuncp, 833 const char *err); 834 835 extern struct value *value_struct_elt_bitpos (struct value **argp, 836 int bitpos, 837 struct type *field_type, 838 const char *err); 839 840 extern struct value *value_aggregate_elt (struct type *curtype, 841 const char *name, 842 struct type *expect_type, 843 int want_address, 844 enum noside noside); 845 846 extern struct value *value_static_field (struct type *type, int fieldno); 847 848 enum oload_search_type { NON_METHOD, METHOD, BOTH }; 849 850 extern int find_overload_match (gdb::array_view<value *> args, 851 const char *name, 852 enum oload_search_type method, 853 struct value **objp, struct symbol *fsym, 854 struct value **valp, struct symbol **symp, 855 int *staticp, const int no_adl, 856 enum noside noside); 857 858 extern struct value *value_field (struct value *arg1, int fieldno); 859 860 extern struct value *value_primitive_field (struct value *arg1, LONGEST offset, 861 int fieldno, 862 struct type *arg_type); 863 864 865 extern struct type *value_rtti_indirect_type (struct value *, int *, LONGEST *, 866 int *); 867 868 extern struct value *value_full_object (struct value *, struct type *, int, 869 int, int); 870 871 extern struct value *value_cast_pointers (struct type *, struct value *, int); 872 873 extern struct value *value_cast (struct type *type, struct value *arg2); 874 875 extern struct value *value_reinterpret_cast (struct type *type, 876 struct value *arg); 877 878 extern struct value *value_dynamic_cast (struct type *type, struct value *arg); 879 880 extern struct value *value_zero (struct type *type, enum lval_type lv); 881 882 extern struct value *value_one (struct type *type); 883 884 extern struct value *value_repeat (struct value *arg1, int count); 885 886 extern struct value *value_subscript (struct value *array, LONGEST index); 887 888 extern struct value *value_bitstring_subscript (struct type *type, 889 struct value *bitstring, 890 LONGEST index); 891 892 extern struct value *register_value_being_returned (struct type *valtype, 893 struct regcache *retbuf); 894 895 extern int value_in (struct value *element, struct value *set); 896 897 extern int value_bit_index (struct type *type, const gdb_byte *addr, 898 int index); 899 900 extern enum return_value_convention 901 struct_return_convention (struct gdbarch *gdbarch, struct value *function, 902 struct type *value_type); 903 904 extern int using_struct_return (struct gdbarch *gdbarch, 905 struct value *function, 906 struct type *value_type); 907 908 extern struct value *evaluate_expression (struct expression *exp); 909 910 extern struct value *evaluate_type (struct expression *exp); 911 912 extern struct value *evaluate_subexp (struct type *expect_type, 913 struct expression *exp, 914 int *pos, enum noside noside); 915 916 extern struct value *evaluate_subexpression_type (struct expression *exp, 917 int subexp); 918 919 extern value *evaluate_var_value (enum noside noside, const block *blk, 920 symbol *var); 921 922 extern value *evaluate_var_msym_value (enum noside noside, 923 struct objfile *objfile, 924 minimal_symbol *msymbol); 925 926 extern value *eval_skip_value (expression *exp); 927 928 extern void fetch_subexp_value (struct expression *exp, int *pc, 929 struct value **valp, struct value **resultp, 930 std::vector<value_ref_ptr> *val_chain, 931 int preserve_errors); 932 933 extern const char *extract_field_op (struct expression *exp, int *subexp); 934 935 extern struct value *evaluate_subexp_with_coercion (struct expression *, 936 int *, enum noside); 937 938 extern struct value *parse_and_eval (const char *exp); 939 940 extern struct value *parse_to_comma_and_eval (const char **expp); 941 942 extern struct type *parse_and_eval_type (char *p, int length); 943 944 extern CORE_ADDR parse_and_eval_address (const char *exp); 945 946 extern LONGEST parse_and_eval_long (const char *exp); 947 948 extern void unop_promote (const struct language_defn *language, 949 struct gdbarch *gdbarch, 950 struct value **arg1); 951 952 extern void binop_promote (const struct language_defn *language, 953 struct gdbarch *gdbarch, 954 struct value **arg1, struct value **arg2); 955 956 extern struct value *access_value_history (int num); 957 958 extern struct value *value_of_internalvar (struct gdbarch *gdbarch, 959 struct internalvar *var); 960 961 extern int get_internalvar_integer (struct internalvar *var, LONGEST *l); 962 963 extern void set_internalvar (struct internalvar *var, struct value *val); 964 965 extern void set_internalvar_integer (struct internalvar *var, LONGEST l); 966 967 extern void set_internalvar_string (struct internalvar *var, 968 const char *string); 969 970 extern void clear_internalvar (struct internalvar *var); 971 972 extern void set_internalvar_component (struct internalvar *var, 973 LONGEST offset, 974 LONGEST bitpos, LONGEST bitsize, 975 struct value *newvalue); 976 977 extern struct internalvar *lookup_only_internalvar (const char *name); 978 979 extern struct internalvar *create_internalvar (const char *name); 980 981 extern void complete_internalvar (completion_tracker &tracker, 982 const char *name); 983 984 /* An internalvar can be dynamically computed by supplying a vector of 985 function pointers to perform various operations. */ 986 987 struct internalvar_funcs 988 { 989 /* Compute the value of the variable. The DATA argument passed to 990 the function is the same argument that was passed to 991 `create_internalvar_type_lazy'. */ 992 993 struct value *(*make_value) (struct gdbarch *arch, 994 struct internalvar *var, 995 void *data); 996 997 /* Update the agent expression EXPR with bytecode to compute the 998 value. VALUE is the agent value we are updating. The DATA 999 argument passed to this function is the same argument that was 1000 passed to `create_internalvar_type_lazy'. If this pointer is 1001 NULL, then the internalvar cannot be compiled to an agent 1002 expression. */ 1003 1004 void (*compile_to_ax) (struct internalvar *var, 1005 struct agent_expr *expr, 1006 struct axs_value *value, 1007 void *data); 1008 1009 /* If non-NULL, this is called to destroy DATA. The DATA argument 1010 passed to this function is the same argument that was passed to 1011 `create_internalvar_type_lazy'. */ 1012 1013 void (*destroy) (void *data); 1014 }; 1015 1016 extern struct internalvar *create_internalvar_type_lazy (const char *name, 1017 const struct internalvar_funcs *funcs, 1018 void *data); 1019 1020 /* Compile an internal variable to an agent expression. VAR is the 1021 variable to compile; EXPR and VALUE are the agent expression we are 1022 updating. This will return 0 if there is no known way to compile 1023 VAR, and 1 if VAR was successfully compiled. It may also throw an 1024 exception on error. */ 1025 1026 extern int compile_internalvar_to_ax (struct internalvar *var, 1027 struct agent_expr *expr, 1028 struct axs_value *value); 1029 1030 extern struct internalvar *lookup_internalvar (const char *name); 1031 1032 extern int value_equal (struct value *arg1, struct value *arg2); 1033 1034 extern int value_equal_contents (struct value *arg1, struct value *arg2); 1035 1036 extern int value_less (struct value *arg1, struct value *arg2); 1037 1038 extern int value_logical_not (struct value *arg1); 1039 1040 /* C++ */ 1041 1042 extern struct value *value_of_this (const struct language_defn *lang); 1043 1044 extern struct value *value_of_this_silent (const struct language_defn *lang); 1045 1046 extern struct value *value_x_binop (struct value *arg1, struct value *arg2, 1047 enum exp_opcode op, 1048 enum exp_opcode otherop, 1049 enum noside noside); 1050 1051 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op, 1052 enum noside noside); 1053 1054 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f, 1055 int j, struct type *type, LONGEST offset); 1056 1057 extern int binop_types_user_defined_p (enum exp_opcode op, 1058 struct type *type1, 1059 struct type *type2); 1060 1061 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1, 1062 struct value *arg2); 1063 1064 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1); 1065 1066 extern int destructor_name_p (const char *name, struct type *type); 1067 1068 extern value_ref_ptr release_value (struct value *val); 1069 1070 extern int record_latest_value (struct value *val); 1071 1072 extern void modify_field (struct type *type, gdb_byte *addr, 1073 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize); 1074 1075 extern void type_print (struct type *type, const char *varstring, 1076 struct ui_file *stream, int show); 1077 1078 extern std::string type_to_string (struct type *type); 1079 1080 extern gdb_byte *baseclass_addr (struct type *type, int index, 1081 gdb_byte *valaddr, 1082 struct value **valuep, int *errp); 1083 1084 extern void print_longest (struct ui_file *stream, int format, 1085 int use_local, LONGEST val); 1086 1087 extern void print_floating (const gdb_byte *valaddr, struct type *type, 1088 struct ui_file *stream); 1089 1090 extern void value_print (struct value *val, struct ui_file *stream, 1091 const struct value_print_options *options); 1092 1093 extern void value_print_array_elements (struct value *val, 1094 struct ui_file *stream, int format, 1095 enum val_prettyformat pretty); 1096 1097 /* Release values from the value chain and return them. Values 1098 created after MARK are released. If MARK is nullptr, or if MARK is 1099 not found on the value chain, then all values are released. Values 1100 are returned in reverse order of creation; that is, newest 1101 first. */ 1102 1103 extern std::vector<value_ref_ptr> value_release_to_mark 1104 (const struct value *mark); 1105 1106 extern void common_val_print (struct value *val, 1107 struct ui_file *stream, int recurse, 1108 const struct value_print_options *options, 1109 const struct language_defn *language); 1110 1111 extern int val_print_string (struct type *elttype, const char *encoding, 1112 CORE_ADDR addr, int len, 1113 struct ui_file *stream, 1114 const struct value_print_options *options); 1115 1116 extern void print_variable_and_value (const char *name, 1117 struct symbol *var, 1118 struct frame_info *frame, 1119 struct ui_file *stream, 1120 int indent); 1121 1122 extern void typedef_print (struct type *type, struct symbol *news, 1123 struct ui_file *stream); 1124 1125 extern char *internalvar_name (const struct internalvar *var); 1126 1127 extern void preserve_values (struct objfile *); 1128 1129 /* From values.c */ 1130 1131 extern struct value *value_copy (struct value *); 1132 1133 extern struct value *value_non_lval (struct value *); 1134 1135 extern void value_force_lval (struct value *, CORE_ADDR); 1136 1137 extern struct value *make_cv_value (int, int, struct value *); 1138 1139 extern void preserve_one_value (struct value *, struct objfile *, htab_t); 1140 1141 /* From valops.c */ 1142 1143 extern struct value *varying_to_slice (struct value *); 1144 1145 extern struct value *value_slice (struct value *, int, int); 1146 1147 /* Create a complex number. The type is the complex type; the values 1148 are cast to the underlying scalar type before the complex number is 1149 created. */ 1150 1151 extern struct value *value_literal_complex (struct value *, struct value *, 1152 struct type *); 1153 1154 /* Return the real part of a complex value. */ 1155 1156 extern struct value *value_real_part (struct value *value); 1157 1158 /* Return the imaginary part of a complex value. */ 1159 1160 extern struct value *value_imaginary_part (struct value *value); 1161 1162 extern struct value *find_function_in_inferior (const char *, 1163 struct objfile **); 1164 1165 extern struct value *value_allocate_space_in_inferior (int); 1166 1167 extern struct value *value_subscripted_rvalue (struct value *array, 1168 LONGEST index, 1169 LONGEST lowerbound); 1170 1171 /* User function handler. */ 1172 1173 typedef struct value *(*internal_function_fn) (struct gdbarch *gdbarch, 1174 const struct language_defn *language, 1175 void *cookie, 1176 int argc, 1177 struct value **argv); 1178 1179 /* Add a new internal function. NAME is the name of the function; DOC 1180 is a documentation string describing the function. HANDLER is 1181 called when the function is invoked. COOKIE is an arbitrary 1182 pointer which is passed to HANDLER and is intended for "user 1183 data". */ 1184 1185 extern void add_internal_function (const char *name, const char *doc, 1186 internal_function_fn handler, 1187 void *cookie); 1188 1189 /* This overload takes an allocated documentation string. */ 1190 1191 extern void add_internal_function (gdb::unique_xmalloc_ptr<char> &&name, 1192 gdb::unique_xmalloc_ptr<char> &&doc, 1193 internal_function_fn handler, 1194 void *cookie); 1195 1196 struct value *call_internal_function (struct gdbarch *gdbarch, 1197 const struct language_defn *language, 1198 struct value *function, 1199 int argc, struct value **argv); 1200 1201 char *value_internal_function_name (struct value *); 1202 1203 /* Build a value wrapping and representing WORKER. The value takes ownership 1204 of the xmethod_worker object. */ 1205 1206 extern struct value *value_from_xmethod (xmethod_worker_up &&worker); 1207 1208 extern struct type *result_type_of_xmethod (struct value *method, 1209 gdb::array_view<value *> argv); 1210 1211 extern struct value *call_xmethod (struct value *method, 1212 gdb::array_view<value *> argv); 1213 1214 /* Destroy the values currently allocated. This is called when GDB is 1215 exiting (e.g., on quit_force). */ 1216 extern void finalize_values (); 1217 1218 #endif /* !defined (VALUE_H) */ 1219