value.h revision 1.1.1.7
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); 616 617 618 620 #include "symtab.h" 621 #include "gdbtypes.h" 622 #include "expression.h" 623 624 struct frame_info; 625 struct fn_field; 626 627 extern int print_address_demangle (const struct value_print_options *, 628 struct gdbarch *, CORE_ADDR, 629 struct ui_file *, int); 630 631 /* Returns true if VAL is of floating-point type. In addition, 632 throws an error if the value is an invalid floating-point value. */ 633 extern bool is_floating_value (struct value *val); 634 635 extern LONGEST value_as_long (struct value *val); 636 extern CORE_ADDR value_as_address (struct value *val); 637 638 extern LONGEST unpack_long (struct type *type, const gdb_byte *valaddr); 639 extern CORE_ADDR unpack_pointer (struct type *type, const gdb_byte *valaddr); 640 641 extern LONGEST unpack_field_as_long (struct type *type, 642 const gdb_byte *valaddr, 643 int fieldno); 644 645 /* Unpack a bitfield of the specified FIELD_TYPE, from the object at 646 VALADDR, and store the result in *RESULT. 647 The bitfield starts at BITPOS bits and contains BITSIZE bits; if 648 BITSIZE is zero, then the length is taken from FIELD_TYPE. 649 650 Extracting bits depends on endianness of the machine. Compute the 651 number of least significant bits to discard. For big endian machines, 652 we compute the total number of bits in the anonymous object, subtract 653 off the bit count from the MSB of the object to the MSB of the 654 bitfield, then the size of the bitfield, which leaves the LSB discard 655 count. For little endian machines, the discard count is simply the 656 number of bits from the LSB of the anonymous object to the LSB of the 657 bitfield. 658 659 If the field is signed, we also do sign extension. */ 660 661 extern LONGEST unpack_bits_as_long (struct type *field_type, 662 const gdb_byte *valaddr, 663 LONGEST bitpos, LONGEST bitsize); 664 665 extern int unpack_value_field_as_long (struct type *type, const gdb_byte *valaddr, 666 LONGEST embedded_offset, int fieldno, 667 const struct value *val, LONGEST *result); 668 669 extern void unpack_value_bitfield (struct value *dest_val, 670 LONGEST bitpos, LONGEST bitsize, 671 const gdb_byte *valaddr, 672 LONGEST embedded_offset, 673 const struct value *val); 674 675 extern struct value *value_field_bitfield (struct type *type, int fieldno, 676 const gdb_byte *valaddr, 677 LONGEST embedded_offset, 678 const struct value *val); 679 680 extern void pack_long (gdb_byte *buf, struct type *type, LONGEST num); 681 682 extern struct value *value_from_longest (struct type *type, LONGEST num); 683 extern struct value *value_from_ulongest (struct type *type, ULONGEST num); 684 extern struct value *value_from_pointer (struct type *type, CORE_ADDR addr); 685 extern struct value *value_from_host_double (struct type *type, double d); 686 extern struct value *value_from_history_ref (const char *, const char **); 687 extern struct value *value_from_component (struct value *, struct type *, 688 LONGEST); 689 690 extern struct value *value_at (struct type *type, CORE_ADDR addr); 691 extern struct value *value_at_lazy (struct type *type, CORE_ADDR addr); 692 693 extern struct value *value_from_contents_and_address_unresolved 694 (struct type *, const gdb_byte *, CORE_ADDR); 695 extern struct value *value_from_contents_and_address (struct type *, 696 const gdb_byte *, 697 CORE_ADDR); 698 extern struct value *value_from_contents (struct type *, const gdb_byte *); 699 700 extern struct value *default_value_from_register (struct gdbarch *gdbarch, 701 struct type *type, 702 int regnum, 703 struct frame_id frame_id); 704 705 extern void read_frame_register_value (struct value *value, 706 struct frame_info *frame); 707 708 extern struct value *value_from_register (struct type *type, int regnum, 709 struct frame_info *frame); 710 711 extern CORE_ADDR address_from_register (int regnum, 712 struct frame_info *frame); 713 714 extern struct value *value_of_variable (struct symbol *var, 715 const struct block *b); 716 717 extern struct value *address_of_variable (struct symbol *var, 718 const struct block *b); 719 720 extern struct value *value_of_register (int regnum, struct frame_info *frame); 721 722 struct value *value_of_register_lazy (struct frame_info *frame, int regnum); 723 724 /* Return the symbol's reading requirement. */ 725 726 extern enum symbol_needs_kind symbol_read_needs (struct symbol *); 727 728 /* Return true if the symbol needs a frame. This is a wrapper for 729 symbol_read_needs that simply checks for SYMBOL_NEEDS_FRAME. */ 730 731 extern int symbol_read_needs_frame (struct symbol *); 732 733 extern struct value *read_var_value (struct symbol *var, 734 const struct block *var_block, 735 struct frame_info *frame); 736 737 extern struct value *allocate_value (struct type *type); 738 extern struct value *allocate_value_lazy (struct type *type); 739 extern void value_contents_copy (struct value *dst, LONGEST dst_offset, 740 struct value *src, LONGEST src_offset, 741 LONGEST length); 742 extern void value_contents_copy_raw (struct value *dst, LONGEST dst_offset, 743 struct value *src, LONGEST src_offset, 744 LONGEST length); 745 746 extern struct value *allocate_repeat_value (struct type *type, int count); 747 748 extern struct value *value_mark (void); 749 750 extern void value_free_to_mark (const struct value *mark); 751 752 /* A helper class that uses value_mark at construction time and calls 753 value_free_to_mark in the destructor. This is used to clear out 754 temporary values created during the lifetime of this object. */ 755 class scoped_value_mark 756 { 757 public: 758 759 scoped_value_mark () 760 : m_value (value_mark ()) 761 { 762 } 763 764 ~scoped_value_mark () 765 { 766 free_to_mark (); 767 } 768 769 scoped_value_mark (scoped_value_mark &&other) = default; 770 771 DISABLE_COPY_AND_ASSIGN (scoped_value_mark); 772 773 /* Free the values currently on the value stack. */ 774 void free_to_mark () 775 { 776 if (m_value != NULL) 777 { 778 value_free_to_mark (m_value); 779 m_value = NULL; 780 } 781 } 782 783 private: 784 785 const struct value *m_value; 786 }; 787 788 extern struct value *value_cstring (const char *ptr, ssize_t len, 789 struct type *char_type); 790 extern struct value *value_string (const char *ptr, ssize_t len, 791 struct type *char_type); 792 793 extern struct value *value_array (int lowbound, int highbound, 794 struct value **elemvec); 795 796 extern struct value *value_concat (struct value *arg1, struct value *arg2); 797 798 extern struct value *value_binop (struct value *arg1, struct value *arg2, 799 enum exp_opcode op); 800 801 extern struct value *value_ptradd (struct value *arg1, LONGEST arg2); 802 803 extern LONGEST value_ptrdiff (struct value *arg1, struct value *arg2); 804 805 /* Return true if VAL does not live in target memory, but should in order 806 to operate on it. Otherwise return false. */ 807 808 extern bool value_must_coerce_to_target (struct value *arg1); 809 810 extern struct value *value_coerce_to_target (struct value *arg1); 811 812 extern struct value *value_coerce_array (struct value *arg1); 813 814 extern struct value *value_coerce_function (struct value *arg1); 815 816 extern struct value *value_ind (struct value *arg1); 817 818 extern struct value *value_addr (struct value *arg1); 819 820 extern struct value *value_ref (struct value *arg1, enum type_code refcode); 821 822 extern struct value *value_assign (struct value *toval, 823 struct value *fromval); 824 825 extern struct value *value_pos (struct value *arg1); 826 827 extern struct value *value_neg (struct value *arg1); 828 829 extern struct value *value_complement (struct value *arg1); 830 831 extern struct value *value_struct_elt (struct value **argp, 832 struct value **args, 833 const char *name, int *static_memfuncp, 834 const char *err); 835 836 extern struct value *value_struct_elt_bitpos (struct value **argp, 837 int bitpos, 838 struct type *field_type, 839 const char *err); 840 841 extern struct value *value_aggregate_elt (struct type *curtype, 842 const char *name, 843 struct type *expect_type, 844 int want_address, 845 enum noside noside); 846 847 extern struct value *value_static_field (struct type *type, int fieldno); 848 849 enum oload_search_type { NON_METHOD, METHOD, BOTH }; 850 851 extern int find_overload_match (gdb::array_view<value *> args, 852 const char *name, 853 enum oload_search_type method, 854 struct value **objp, struct symbol *fsym, 855 struct value **valp, struct symbol **symp, 856 int *staticp, const int no_adl, 857 enum noside noside); 858 859 extern struct value *value_field (struct value *arg1, int fieldno); 860 861 extern struct value *value_primitive_field (struct value *arg1, LONGEST offset, 862 int fieldno, 863 struct type *arg_type); 864 865 866 extern struct type *value_rtti_indirect_type (struct value *, int *, LONGEST *, 867 int *); 868 869 extern struct value *value_full_object (struct value *, struct type *, int, 870 int, int); 871 872 extern struct value *value_cast_pointers (struct type *, struct value *, int); 873 874 extern struct value *value_cast (struct type *type, struct value *arg2); 875 876 extern struct value *value_reinterpret_cast (struct type *type, 877 struct value *arg); 878 879 extern struct value *value_dynamic_cast (struct type *type, struct value *arg); 880 881 extern struct value *value_zero (struct type *type, enum lval_type lv); 882 883 extern struct value *value_one (struct type *type); 884 885 extern struct value *value_repeat (struct value *arg1, int count); 886 887 extern struct value *value_subscript (struct value *array, LONGEST index); 888 889 extern struct value *value_bitstring_subscript (struct type *type, 890 struct value *bitstring, 891 LONGEST index); 892 893 extern struct value *register_value_being_returned (struct type *valtype, 894 struct regcache *retbuf); 895 896 extern int value_in (struct value *element, struct value *set); 897 898 extern int value_bit_index (struct type *type, const gdb_byte *addr, 899 int index); 900 901 extern enum return_value_convention 902 struct_return_convention (struct gdbarch *gdbarch, struct value *function, 903 struct type *value_type); 904 905 extern int using_struct_return (struct gdbarch *gdbarch, 906 struct value *function, 907 struct type *value_type); 908 909 extern struct value *evaluate_expression (struct expression *exp); 910 911 extern struct value *evaluate_type (struct expression *exp); 912 913 extern struct value *evaluate_subexp (struct type *expect_type, 914 struct expression *exp, 915 int *pos, enum noside noside); 916 917 extern struct value *evaluate_subexpression_type (struct expression *exp, 918 int subexp); 919 920 extern value *evaluate_var_value (enum noside noside, const block *blk, 921 symbol *var); 922 923 extern value *evaluate_var_msym_value (enum noside noside, 924 struct objfile *objfile, 925 minimal_symbol *msymbol); 926 927 extern value *eval_skip_value (expression *exp); 928 929 extern void fetch_subexp_value (struct expression *exp, int *pc, 930 struct value **valp, struct value **resultp, 931 std::vector<value_ref_ptr> *val_chain, 932 int preserve_errors); 933 934 extern const char *extract_field_op (struct expression *exp, int *subexp); 935 936 extern struct value *evaluate_subexp_with_coercion (struct expression *, 937 int *, enum noside); 938 939 extern struct value *parse_and_eval (const char *exp); 940 941 extern struct value *parse_to_comma_and_eval (const char **expp); 942 943 extern struct type *parse_and_eval_type (char *p, int length); 944 945 extern CORE_ADDR parse_and_eval_address (const char *exp); 946 947 extern LONGEST parse_and_eval_long (const char *exp); 948 949 extern void unop_promote (const struct language_defn *language, 950 struct gdbarch *gdbarch, 951 struct value **arg1); 952 953 extern void binop_promote (const struct language_defn *language, 954 struct gdbarch *gdbarch, 955 struct value **arg1, struct value **arg2); 956 957 extern struct value *access_value_history (int num); 958 959 extern struct value *value_of_internalvar (struct gdbarch *gdbarch, 960 struct internalvar *var); 961 962 extern int get_internalvar_integer (struct internalvar *var, LONGEST *l); 963 964 extern void set_internalvar (struct internalvar *var, struct value *val); 965 966 extern void set_internalvar_integer (struct internalvar *var, LONGEST l); 967 968 extern void set_internalvar_string (struct internalvar *var, 969 const char *string); 970 971 extern void clear_internalvar (struct internalvar *var); 972 973 extern void set_internalvar_component (struct internalvar *var, 974 LONGEST offset, 975 LONGEST bitpos, LONGEST bitsize, 976 struct value *newvalue); 977 978 extern struct internalvar *lookup_only_internalvar (const char *name); 979 980 extern struct internalvar *create_internalvar (const char *name); 981 982 extern void complete_internalvar (completion_tracker &tracker, 983 const char *name); 984 985 /* An internalvar can be dynamically computed by supplying a vector of 986 function pointers to perform various operations. */ 987 988 struct internalvar_funcs 989 { 990 /* Compute the value of the variable. The DATA argument passed to 991 the function is the same argument that was passed to 992 `create_internalvar_type_lazy'. */ 993 994 struct value *(*make_value) (struct gdbarch *arch, 995 struct internalvar *var, 996 void *data); 997 998 /* Update the agent expression EXPR with bytecode to compute the 999 value. VALUE is the agent value we are updating. The DATA 1000 argument passed to this function is the same argument that was 1001 passed to `create_internalvar_type_lazy'. If this pointer is 1002 NULL, then the internalvar cannot be compiled to an agent 1003 expression. */ 1004 1005 void (*compile_to_ax) (struct internalvar *var, 1006 struct agent_expr *expr, 1007 struct axs_value *value, 1008 void *data); 1009 1010 /* If non-NULL, this is called to destroy DATA. The DATA argument 1011 passed to this function is the same argument that was passed to 1012 `create_internalvar_type_lazy'. */ 1013 1014 void (*destroy) (void *data); 1015 }; 1016 1017 extern struct internalvar *create_internalvar_type_lazy (const char *name, 1018 const struct internalvar_funcs *funcs, 1019 void *data); 1020 1021 /* Compile an internal variable to an agent expression. VAR is the 1022 variable to compile; EXPR and VALUE are the agent expression we are 1023 updating. This will return 0 if there is no known way to compile 1024 VAR, and 1 if VAR was successfully compiled. It may also throw an 1025 exception on error. */ 1026 1027 extern int compile_internalvar_to_ax (struct internalvar *var, 1028 struct agent_expr *expr, 1029 struct axs_value *value); 1030 1031 extern struct internalvar *lookup_internalvar (const char *name); 1032 1033 extern int value_equal (struct value *arg1, struct value *arg2); 1034 1035 extern int value_equal_contents (struct value *arg1, struct value *arg2); 1036 1037 extern int value_less (struct value *arg1, struct value *arg2); 1038 1039 extern int value_logical_not (struct value *arg1); 1040 1041 /* C++ */ 1042 1043 extern struct value *value_of_this (const struct language_defn *lang); 1044 1045 extern struct value *value_of_this_silent (const struct language_defn *lang); 1046 1047 extern struct value *value_x_binop (struct value *arg1, struct value *arg2, 1048 enum exp_opcode op, 1049 enum exp_opcode otherop, 1050 enum noside noside); 1051 1052 extern struct value *value_x_unop (struct value *arg1, enum exp_opcode op, 1053 enum noside noside); 1054 1055 extern struct value *value_fn_field (struct value **arg1p, struct fn_field *f, 1056 int j, struct type *type, LONGEST offset); 1057 1058 extern int binop_types_user_defined_p (enum exp_opcode op, 1059 struct type *type1, 1060 struct type *type2); 1061 1062 extern int binop_user_defined_p (enum exp_opcode op, struct value *arg1, 1063 struct value *arg2); 1064 1065 extern int unop_user_defined_p (enum exp_opcode op, struct value *arg1); 1066 1067 extern int destructor_name_p (const char *name, struct type *type); 1068 1069 extern value_ref_ptr release_value (struct value *val); 1070 1071 extern int record_latest_value (struct value *val); 1072 1073 extern void modify_field (struct type *type, gdb_byte *addr, 1074 LONGEST fieldval, LONGEST bitpos, LONGEST bitsize); 1075 1076 extern void type_print (struct type *type, const char *varstring, 1077 struct ui_file *stream, int show); 1078 1079 extern std::string type_to_string (struct type *type); 1080 1081 extern gdb_byte *baseclass_addr (struct type *type, int index, 1082 gdb_byte *valaddr, 1083 struct value **valuep, int *errp); 1084 1085 extern void print_longest (struct ui_file *stream, int format, 1086 int use_local, LONGEST val); 1087 1088 extern void print_floating (const gdb_byte *valaddr, struct type *type, 1089 struct ui_file *stream); 1090 1091 extern void value_print (struct value *val, struct ui_file *stream, 1092 const struct value_print_options *options); 1093 1094 extern void value_print_array_elements (struct value *val, 1095 struct ui_file *stream, int format, 1096 enum val_prettyformat pretty); 1097 1098 /* Release values from the value chain and return them. Values 1099 created after MARK are released. If MARK is nullptr, or if MARK is 1100 not found on the value chain, then all values are released. Values 1101 are returned in reverse order of creation; that is, newest 1102 first. */ 1103 1104 extern std::vector<value_ref_ptr> value_release_to_mark 1105 (const struct value *mark); 1106 1107 extern void common_val_print (struct value *val, 1108 struct ui_file *stream, int recurse, 1109 const struct value_print_options *options, 1110 const struct language_defn *language); 1111 1112 extern int val_print_string (struct type *elttype, const char *encoding, 1113 CORE_ADDR addr, int len, 1114 struct ui_file *stream, 1115 const struct value_print_options *options); 1116 1117 extern void print_variable_and_value (const char *name, 1118 struct symbol *var, 1119 struct frame_info *frame, 1120 struct ui_file *stream, 1121 int indent); 1122 1123 extern void typedef_print (struct type *type, struct symbol *news, 1124 struct ui_file *stream); 1125 1126 extern char *internalvar_name (const struct internalvar *var); 1127 1128 extern void preserve_values (struct objfile *); 1129 1130 /* From values.c */ 1131 1132 extern struct value *value_copy (struct value *); 1133 1134 extern struct value *value_non_lval (struct value *); 1135 1136 extern void value_force_lval (struct value *, CORE_ADDR); 1137 1138 extern struct value *make_cv_value (int, int, struct value *); 1139 1140 extern void preserve_one_value (struct value *, struct objfile *, htab_t); 1141 1142 /* From valops.c */ 1143 1144 extern struct value *varying_to_slice (struct value *); 1145 1146 extern struct value *value_slice (struct value *, int, int); 1147 1148 /* Create a complex number. The type is the complex type; the values 1149 are cast to the underlying scalar type before the complex number is 1150 created. */ 1151 1152 extern struct value *value_literal_complex (struct value *, struct value *, 1153 struct type *); 1154 1155 /* Return the real part of a complex value. */ 1156 1157 extern struct value *value_real_part (struct value *value); 1158 1159 /* Return the imaginary part of a complex value. */ 1160 1161 extern struct value *value_imaginary_part (struct value *value); 1162 1163 extern struct value *find_function_in_inferior (const char *, 1164 struct objfile **); 1165 1166 extern struct value *value_allocate_space_in_inferior (int); 1167 1168 extern struct value *value_subscripted_rvalue (struct value *array, 1169 LONGEST index, 1170 LONGEST lowerbound); 1171 1172 /* User function handler. */ 1173 1174 typedef struct value *(*internal_function_fn) (struct gdbarch *gdbarch, 1175 const struct language_defn *language, 1176 void *cookie, 1177 int argc, 1178 struct value **argv); 1179 1180 /* Add a new internal function. NAME is the name of the function; DOC 1181 is a documentation string describing the function. HANDLER is 1182 called when the function is invoked. COOKIE is an arbitrary 1183 pointer which is passed to HANDLER and is intended for "user 1184 data". */ 1185 1186 extern void add_internal_function (const char *name, const char *doc, 1187 internal_function_fn handler, 1188 void *cookie); 1189 1190 /* This overload takes an allocated documentation string. */ 1191 1192 extern void add_internal_function (gdb::unique_xmalloc_ptr<char> &&name, 1193 gdb::unique_xmalloc_ptr<char> &&doc, 1194 internal_function_fn handler, 1195 void *cookie); 1196 1197 struct value *call_internal_function (struct gdbarch *gdbarch, 1198 const struct language_defn *language, 1199 struct value *function, 1200 int argc, struct value **argv); 1201 1202 char *value_internal_function_name (struct value *); 1203 1204 /* Build a value wrapping and representing WORKER. The value takes ownership 1205 of the xmethod_worker object. */ 1206 1207 extern struct value *value_from_xmethod (xmethod_worker_up &&worker); 1208 1209 extern struct type *result_type_of_xmethod (struct value *method, 1210 gdb::array_view<value *> argv); 1211 1212 extern struct value *call_xmethod (struct value *method, 1213 gdb::array_view<value *> argv); 1214 1215 /* Destroy the values currently allocated. This is called when GDB is 1216 exiting (e.g., on quit_force). */ 1217 extern void finalize_values (); 1218 1219 #endif /* !defined (VALUE_H) */ 1220
Indexes created Sun Mar 01 05:31:48 UTC 2026