valops.c revision 1.9 1 /* Perform non-arithmetic operations on values, 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 #include "defs.h"
21 #include "symtab.h"
22 #include "gdbtypes.h"
23 #include "value.h"
24 #include "frame.h"
25 #include "inferior.h"
26 #include "gdbcore.h"
27 #include "target.h"
28 #include "demangle.h"
29 #include "language.h"
30 #include "gdbcmd.h"
31 #include "regcache.h"
32 #include "cp-abi.h"
33 #include "block.h"
34 #include "infcall.h"
35 #include "dictionary.h"
36 #include "cp-support.h"
37 #include "target-float.h"
38 #include "tracepoint.h"
39 #include "observable.h"
40 #include "objfiles.h"
41 #include "extension.h"
42 #include "gdbtypes.h"
43 #include "gdbsupport/byte-vector.h"
44
45 /* Local functions. */
46
47 static int typecmp (int staticp, int varargs, int nargs,
48 struct field t1[], struct value *t2[]);
49
50 static struct value *search_struct_field (const char *, struct value *,
51 struct type *, int);
52
53 static struct value *search_struct_method (const char *, struct value **,
54 struct value **,
55 LONGEST, int *, struct type *);
56
57 static int find_oload_champ_namespace (gdb::array_view<value *> args,
58 const char *, const char *,
59 std::vector<symbol *> *oload_syms,
60 badness_vector *,
61 const int no_adl);
62
63 static int find_oload_champ_namespace_loop (gdb::array_view<value *> args,
64 const char *, const char *,
65 int, std::vector<symbol *> *oload_syms,
66 badness_vector *, int *,
67 const int no_adl);
68
69 static int find_oload_champ (gdb::array_view<value *> args,
70 size_t num_fns,
71 fn_field *methods,
72 xmethod_worker_up *xmethods,
73 symbol **functions,
74 badness_vector *oload_champ_bv);
75
76 static int oload_method_static_p (struct fn_field *, int);
77
78 enum oload_classification { STANDARD, NON_STANDARD, INCOMPATIBLE };
79
80 static enum oload_classification classify_oload_match
81 (const badness_vector &, int, int);
82
83 static struct value *value_struct_elt_for_reference (struct type *,
84 int, struct type *,
85 const char *,
86 struct type *,
87 int, enum noside);
88
89 static struct value *value_namespace_elt (const struct type *,
90 const char *, int , enum noside);
91
92 static struct value *value_maybe_namespace_elt (const struct type *,
93 const char *, int,
94 enum noside);
95
96 static CORE_ADDR allocate_space_in_inferior (int);
97
98 static struct value *cast_into_complex (struct type *, struct value *);
99
100 bool overload_resolution = false;
101 static void
102 show_overload_resolution (struct ui_file *file, int from_tty,
103 struct cmd_list_element *c,
104 const char *value)
105 {
106 fprintf_filtered (file, _("Overload resolution in evaluating "
107 "C++ functions is %s.\n"),
108 value);
109 }
110
111 /* Find the address of function name NAME in the inferior. If OBJF_P
112 is non-NULL, *OBJF_P will be set to the OBJFILE where the function
113 is defined. */
114
115 struct value *
116 find_function_in_inferior (const char *name, struct objfile **objf_p)
117 {
118 struct block_symbol sym;
119
120 sym = lookup_symbol (name, 0, VAR_DOMAIN, 0);
121 if (sym.symbol != NULL)
122 {
123 if (SYMBOL_CLASS (sym.symbol) != LOC_BLOCK)
124 {
125 error (_("\"%s\" exists in this program but is not a function."),
126 name);
127 }
128
129 if (objf_p)
130 *objf_p = symbol_objfile (sym.symbol);
131
132 return value_of_variable (sym.symbol, sym.block);
133 }
134 else
135 {
136 struct bound_minimal_symbol msymbol =
137 lookup_bound_minimal_symbol (name);
138
139 if (msymbol.minsym != NULL)
140 {
141 struct objfile *objfile = msymbol.objfile;
142 struct gdbarch *gdbarch = objfile->arch ();
143
144 struct type *type;
145 CORE_ADDR maddr;
146 type = lookup_pointer_type (builtin_type (gdbarch)->builtin_char);
147 type = lookup_function_type (type);
148 type = lookup_pointer_type (type);
149 maddr = BMSYMBOL_VALUE_ADDRESS (msymbol);
150
151 if (objf_p)
152 *objf_p = objfile;
153
154 return value_from_pointer (type, maddr);
155 }
156 else
157 {
158 if (!target_has_execution)
159 error (_("evaluation of this expression "
160 "requires the target program to be active"));
161 else
162 error (_("evaluation of this expression requires the "
163 "program to have a function \"%s\"."),
164 name);
165 }
166 }
167 }
168
169 /* Allocate NBYTES of space in the inferior using the inferior's
170 malloc and return a value that is a pointer to the allocated
171 space. */
172
173 struct value *
174 value_allocate_space_in_inferior (int len)
175 {
176 struct objfile *objf;
177 struct value *val = find_function_in_inferior ("malloc", &objf);
178 struct gdbarch *gdbarch = objf->arch ();
179 struct value *blocklen;
180
181 blocklen = value_from_longest (builtin_type (gdbarch)->builtin_int, len);
182 val = call_function_by_hand (val, NULL, blocklen);
183 if (value_logical_not (val))
184 {
185 if (!target_has_execution)
186 error (_("No memory available to program now: "
187 "you need to start the target first"));
188 else
189 error (_("No memory available to program: call to malloc failed"));
190 }
191 return val;
192 }
193
194 static CORE_ADDR
195 allocate_space_in_inferior (int len)
196 {
197 return value_as_long (value_allocate_space_in_inferior (len));
198 }
199
200 /* Cast struct value VAL to type TYPE and return as a value.
201 Both type and val must be of TYPE_CODE_STRUCT or TYPE_CODE_UNION
202 for this to work. Typedef to one of the codes is permitted.
203 Returns NULL if the cast is neither an upcast nor a downcast. */
204
205 static struct value *
206 value_cast_structs (struct type *type, struct value *v2)
207 {
208 struct type *t1;
209 struct type *t2;
210 struct value *v;
211
212 gdb_assert (type != NULL && v2 != NULL);
213
214 t1 = check_typedef (type);
215 t2 = check_typedef (value_type (v2));
216
217 /* Check preconditions. */
218 gdb_assert ((t1->code () == TYPE_CODE_STRUCT
219 || t1->code () == TYPE_CODE_UNION)
220 && !!"Precondition is that type is of STRUCT or UNION kind.");
221 gdb_assert ((t2->code () == TYPE_CODE_STRUCT
222 || t2->code () == TYPE_CODE_UNION)
223 && !!"Precondition is that value is of STRUCT or UNION kind");
224
225 if (t1->name () != NULL
226 && t2->name () != NULL
227 && !strcmp (t1->name (), t2->name ()))
228 return NULL;
229
230 /* Upcasting: look in the type of the source to see if it contains the
231 type of the target as a superclass. If so, we'll need to
232 offset the pointer rather than just change its type. */
233 if (t1->name () != NULL)
234 {
235 v = search_struct_field (t1->name (),
236 v2, t2, 1);
237 if (v)
238 return v;
239 }
240
241 /* Downcasting: look in the type of the target to see if it contains the
242 type of the source as a superclass. If so, we'll need to
243 offset the pointer rather than just change its type. */
244 if (t2->name () != NULL)
245 {
246 /* Try downcasting using the run-time type of the value. */
247 int full, using_enc;
248 LONGEST top;
249 struct type *real_type;
250
251 real_type = value_rtti_type (v2, &full, &top, &using_enc);
252 if (real_type)
253 {
254 v = value_full_object (v2, real_type, full, top, using_enc);
255 v = value_at_lazy (real_type, value_address (v));
256 real_type = value_type (v);
257
258 /* We might be trying to cast to the outermost enclosing
259 type, in which case search_struct_field won't work. */
260 if (real_type->name () != NULL
261 && !strcmp (real_type->name (), t1->name ()))
262 return v;
263
264 v = search_struct_field (t2->name (), v, real_type, 1);
265 if (v)
266 return v;
267 }
268
269 /* Try downcasting using information from the destination type
270 T2. This wouldn't work properly for classes with virtual
271 bases, but those were handled above. */
272 v = search_struct_field (t2->name (),
273 value_zero (t1, not_lval), t1, 1);
274 if (v)
275 {
276 /* Downcasting is possible (t1 is superclass of v2). */
277 CORE_ADDR addr2 = value_address (v2);
278
279 addr2 -= value_address (v) + value_embedded_offset (v);
280 return value_at (type, addr2);
281 }
282 }
283
284 return NULL;
285 }
286
287 /* Cast one pointer or reference type to another. Both TYPE and
288 the type of ARG2 should be pointer types, or else both should be
289 reference types. If SUBCLASS_CHECK is non-zero, this will force a
290 check to see whether TYPE is a superclass of ARG2's type. If
291 SUBCLASS_CHECK is zero, then the subclass check is done only when
292 ARG2 is itself non-zero. Returns the new pointer or reference. */
293
294 struct value *
295 value_cast_pointers (struct type *type, struct value *arg2,
296 int subclass_check)
297 {
298 struct type *type1 = check_typedef (type);
299 struct type *type2 = check_typedef (value_type (arg2));
300 struct type *t1 = check_typedef (TYPE_TARGET_TYPE (type1));
301 struct type *t2 = check_typedef (TYPE_TARGET_TYPE (type2));
302
303 if (t1->code () == TYPE_CODE_STRUCT
304 && t2->code () == TYPE_CODE_STRUCT
305 && (subclass_check || !value_logical_not (arg2)))
306 {
307 struct value *v2;
308
309 if (TYPE_IS_REFERENCE (type2))
310 v2 = coerce_ref (arg2);
311 else
312 v2 = value_ind (arg2);
313 gdb_assert (check_typedef (value_type (v2))->code ()
314 == TYPE_CODE_STRUCT && !!"Why did coercion fail?");
315 v2 = value_cast_structs (t1, v2);
316 /* At this point we have what we can have, un-dereference if needed. */
317 if (v2)
318 {
319 struct value *v = value_addr (v2);
320
321 deprecated_set_value_type (v, type);
322 return v;
323 }
324 }
325
326 /* No superclass found, just change the pointer type. */
327 arg2 = value_copy (arg2);
328 deprecated_set_value_type (arg2, type);
329 set_value_enclosing_type (arg2, type);
330 set_value_pointed_to_offset (arg2, 0); /* pai: chk_val */
331 return arg2;
332 }
333
334 /* Cast value ARG2 to type TYPE and return as a value.
335 More general than a C cast: accepts any two types of the same length,
336 and if ARG2 is an lvalue it can be cast into anything at all. */
337 /* In C++, casts may change pointer or object representations. */
338
339 struct value *
340 value_cast (struct type *type, struct value *arg2)
341 {
342 enum type_code code1;
343 enum type_code code2;
344 int scalar;
345 struct type *type2;
346
347 int convert_to_boolean = 0;
348
349 if (value_type (arg2) == type)
350 return arg2;
351
352 /* Check if we are casting struct reference to struct reference. */
353 if (TYPE_IS_REFERENCE (check_typedef (type)))
354 {
355 /* We dereference type; then we recurse and finally
356 we generate value of the given reference. Nothing wrong with
357 that. */
358 struct type *t1 = check_typedef (type);
359 struct type *dereftype = check_typedef (TYPE_TARGET_TYPE (t1));
360 struct value *val = value_cast (dereftype, arg2);
361
362 return value_ref (val, t1->code ());
363 }
364
365 if (TYPE_IS_REFERENCE (check_typedef (value_type (arg2))))
366 /* We deref the value and then do the cast. */
367 return value_cast (type, coerce_ref (arg2));
368
369 /* Strip typedefs / resolve stubs in order to get at the type's
370 code/length, but remember the original type, to use as the
371 resulting type of the cast, in case it was a typedef. */
372 struct type *to_type = type;
373
374 type = check_typedef (type);
375 code1 = type->code ();
376 arg2 = coerce_ref (arg2);
377 type2 = check_typedef (value_type (arg2));
378
379 /* You can't cast to a reference type. See value_cast_pointers
380 instead. */
381 gdb_assert (!TYPE_IS_REFERENCE (type));
382
383 /* A cast to an undetermined-length array_type, such as
384 (TYPE [])OBJECT, is treated like a cast to (TYPE [N])OBJECT,
385 where N is sizeof(OBJECT)/sizeof(TYPE). */
386 if (code1 == TYPE_CODE_ARRAY)
387 {
388 struct type *element_type = TYPE_TARGET_TYPE (type);
389 unsigned element_length = TYPE_LENGTH (check_typedef (element_type));
390
391 if (element_length > 0 && type->bounds ()->high.kind () == PROP_UNDEFINED)
392 {
393 struct type *range_type = type->index_type ();
394 int val_length = TYPE_LENGTH (type2);
395 LONGEST low_bound, high_bound, new_length;
396
397 if (get_discrete_bounds (range_type, &low_bound, &high_bound) < 0)
398 low_bound = 0, high_bound = 0;
399 new_length = val_length / element_length;
400 if (val_length % element_length != 0)
401 warning (_("array element type size does not "
402 "divide object size in cast"));
403 /* FIXME-type-allocation: need a way to free this type when
404 we are done with it. */
405 range_type = create_static_range_type (NULL,
406 TYPE_TARGET_TYPE (range_type),
407 low_bound,
408 new_length + low_bound - 1);
409 deprecated_set_value_type (arg2,
410 create_array_type (NULL,
411 element_type,
412 range_type));
413 return arg2;
414 }
415 }
416
417 if (current_language->c_style_arrays
418 && type2->code () == TYPE_CODE_ARRAY
419 && !TYPE_VECTOR (type2))
420 arg2 = value_coerce_array (arg2);
421
422 if (type2->code () == TYPE_CODE_FUNC)
423 arg2 = value_coerce_function (arg2);
424
425 type2 = check_typedef (value_type (arg2));
426 code2 = type2->code ();
427
428 if (code1 == TYPE_CODE_COMPLEX)
429 return cast_into_complex (to_type, arg2);
430 if (code1 == TYPE_CODE_BOOL)
431 {
432 code1 = TYPE_CODE_INT;
433 convert_to_boolean = 1;
434 }
435 if (code1 == TYPE_CODE_CHAR)
436 code1 = TYPE_CODE_INT;
437 if (code2 == TYPE_CODE_BOOL || code2 == TYPE_CODE_CHAR)
438 code2 = TYPE_CODE_INT;
439
440 scalar = (code2 == TYPE_CODE_INT || code2 == TYPE_CODE_FLT
441 || code2 == TYPE_CODE_DECFLOAT || code2 == TYPE_CODE_ENUM
442 || code2 == TYPE_CODE_RANGE);
443
444 if ((code1 == TYPE_CODE_STRUCT || code1 == TYPE_CODE_UNION)
445 && (code2 == TYPE_CODE_STRUCT || code2 == TYPE_CODE_UNION)
446 && type->name () != 0)
447 {
448 struct value *v = value_cast_structs (to_type, arg2);
449
450 if (v)
451 return v;
452 }
453
454 if (is_floating_type (type) && scalar)
455 {
456 if (is_floating_value (arg2))
457 {
458 struct value *v = allocate_value (to_type);
459 target_float_convert (value_contents (arg2), type2,
460 value_contents_raw (v), type);
461 return v;
462 }
463
464 /* The only option left is an integral type. */
465 if (TYPE_UNSIGNED (type2))
466 return value_from_ulongest (to_type, value_as_long (arg2));
467 else
468 return value_from_longest (to_type, value_as_long (arg2));
469 }
470 else if ((code1 == TYPE_CODE_INT || code1 == TYPE_CODE_ENUM
471 || code1 == TYPE_CODE_RANGE)
472 && (scalar || code2 == TYPE_CODE_PTR
473 || code2 == TYPE_CODE_MEMBERPTR))
474 {
475 LONGEST longest;
476
477 /* When we cast pointers to integers, we mustn't use
478 gdbarch_pointer_to_address to find the address the pointer
479 represents, as value_as_long would. GDB should evaluate
480 expressions just as the compiler would --- and the compiler
481 sees a cast as a simple reinterpretation of the pointer's
482 bits. */
483 if (code2 == TYPE_CODE_PTR)
484 longest = extract_unsigned_integer
485 (value_contents (arg2), TYPE_LENGTH (type2),
486 type_byte_order (type2));
487 else
488 longest = value_as_long (arg2);
489 return value_from_longest (to_type, convert_to_boolean ?
490 (LONGEST) (longest ? 1 : 0) : longest);
491 }
492 else if (code1 == TYPE_CODE_PTR && (code2 == TYPE_CODE_INT
493 || code2 == TYPE_CODE_ENUM
494 || code2 == TYPE_CODE_RANGE))
495 {
496 /* TYPE_LENGTH (type) is the length of a pointer, but we really
497 want the length of an address! -- we are really dealing with
498 addresses (i.e., gdb representations) not pointers (i.e.,
499 target representations) here.
500
501 This allows things like "print *(int *)0x01000234" to work
502 without printing a misleading message -- which would
503 otherwise occur when dealing with a target having two byte
504 pointers and four byte addresses. */
505
506 int addr_bit = gdbarch_addr_bit (get_type_arch (type2));
507 LONGEST longest = value_as_long (arg2);
508
509 if (addr_bit < sizeof (LONGEST) * HOST_CHAR_BIT)
510 {
511 if (longest >= ((LONGEST) 1 << addr_bit)
512 || longest <= -((LONGEST) 1 << addr_bit))
513 warning (_("value truncated"));
514 }
515 return value_from_longest (to_type, longest);
516 }
517 else if (code1 == TYPE_CODE_METHODPTR && code2 == TYPE_CODE_INT
518 && value_as_long (arg2) == 0)
519 {
520 struct value *result = allocate_value (to_type);
521
522 cplus_make_method_ptr (to_type, value_contents_writeable (result), 0, 0);
523 return result;
524 }
525 else if (code1 == TYPE_CODE_MEMBERPTR && code2 == TYPE_CODE_INT
526 && value_as_long (arg2) == 0)
527 {
528 /* The Itanium C++ ABI represents NULL pointers to members as
529 minus one, instead of biasing the normal case. */
530 return value_from_longest (to_type, -1);
531 }
532 else if (code1 == TYPE_CODE_ARRAY && TYPE_VECTOR (type)
533 && code2 == TYPE_CODE_ARRAY && TYPE_VECTOR (type2)
534 && TYPE_LENGTH (type) != TYPE_LENGTH (type2))
535 error (_("Cannot convert between vector values of different sizes"));
536 else if (code1 == TYPE_CODE_ARRAY && TYPE_VECTOR (type) && scalar
537 && TYPE_LENGTH (type) != TYPE_LENGTH (type2))
538 error (_("can only cast scalar to vector of same size"));
539 else if (code1 == TYPE_CODE_VOID)
540 {
541 return value_zero (to_type, not_lval);
542 }
543 else if (TYPE_LENGTH (type) == TYPE_LENGTH (type2))
544 {
545 if (code1 == TYPE_CODE_PTR && code2 == TYPE_CODE_PTR)
546 return value_cast_pointers (to_type, arg2, 0);
547
548 arg2 = value_copy (arg2);
549 deprecated_set_value_type (arg2, to_type);
550 set_value_enclosing_type (arg2, to_type);
551 set_value_pointed_to_offset (arg2, 0); /* pai: chk_val */
552 return arg2;
553 }
554 else if (VALUE_LVAL (arg2) == lval_memory)
555 return value_at_lazy (to_type, value_address (arg2));
556 else
557 {
558 if (current_language->la_language == language_ada)
559 error (_("Invalid type conversion."));
560 error (_("Invalid cast."));
561 }
562 }
563
564 /* The C++ reinterpret_cast operator. */
565
566 struct value *
567 value_reinterpret_cast (struct type *type, struct value *arg)
568 {
569 struct value *result;
570 struct type *real_type = check_typedef (type);
571 struct type *arg_type, *dest_type;
572 int is_ref = 0;
573 enum type_code dest_code, arg_code;
574
575 /* Do reference, function, and array conversion. */
576 arg = coerce_array (arg);
577
578 /* Attempt to preserve the type the user asked for. */
579 dest_type = type;
580
581 /* If we are casting to a reference type, transform
582 reinterpret_cast<T&[&]>(V) to *reinterpret_cast<T*>(&V). */
583 if (TYPE_IS_REFERENCE (real_type))
584 {
585 is_ref = 1;
586 arg = value_addr (arg);
587 dest_type = lookup_pointer_type (TYPE_TARGET_TYPE (dest_type));
588 real_type = lookup_pointer_type (real_type);
589 }
590
591 arg_type = value_type (arg);
592
593 dest_code = real_type->code ();
594 arg_code = arg_type->code ();
595
596 /* We can convert pointer types, or any pointer type to int, or int
597 type to pointer. */
598 if ((dest_code == TYPE_CODE_PTR && arg_code == TYPE_CODE_INT)
599 || (dest_code == TYPE_CODE_INT && arg_code == TYPE_CODE_PTR)
600 || (dest_code == TYPE_CODE_METHODPTR && arg_code == TYPE_CODE_INT)
601 || (dest_code == TYPE_CODE_INT && arg_code == TYPE_CODE_METHODPTR)
602 || (dest_code == TYPE_CODE_MEMBERPTR && arg_code == TYPE_CODE_INT)
603 || (dest_code == TYPE_CODE_INT && arg_code == TYPE_CODE_MEMBERPTR)
604 || (dest_code == arg_code
605 && (dest_code == TYPE_CODE_PTR
606 || dest_code == TYPE_CODE_METHODPTR
607 || dest_code == TYPE_CODE_MEMBERPTR)))
608 result = value_cast (dest_type, arg);
609 else
610 error (_("Invalid reinterpret_cast"));
611
612 if (is_ref)
613 result = value_cast (type, value_ref (value_ind (result),
614 type->code ()));
615
616 return result;
617 }
618
619 /* A helper for value_dynamic_cast. This implements the first of two
620 runtime checks: we iterate over all the base classes of the value's
621 class which are equal to the desired class; if only one of these
622 holds the value, then it is the answer. */
623
624 static int
625 dynamic_cast_check_1 (struct type *desired_type,
626 const gdb_byte *valaddr,
627 LONGEST embedded_offset,
628 CORE_ADDR address,
629 struct value *val,
630 struct type *search_type,
631 CORE_ADDR arg_addr,
632 struct type *arg_type,
633 struct value **result)
634 {
635 int i, result_count = 0;
636
637 for (i = 0; i < TYPE_N_BASECLASSES (search_type) && result_count < 2; ++i)
638 {
639 LONGEST offset = baseclass_offset (search_type, i, valaddr,
640 embedded_offset,
641 address, val);
642
643 if (class_types_same_p (desired_type, TYPE_BASECLASS (search_type, i)))
644 {
645 if (address + embedded_offset + offset >= arg_addr
646 && address + embedded_offset + offset < arg_addr + TYPE_LENGTH (arg_type))
647 {
648 ++result_count;
649 if (!*result)
650 *result = value_at_lazy (TYPE_BASECLASS (search_type, i),
651 address + embedded_offset + offset);
652 }
653 }
654 else
655 result_count += dynamic_cast_check_1 (desired_type,
656 valaddr,
657 embedded_offset + offset,
658 address, val,
659 TYPE_BASECLASS (search_type, i),
660 arg_addr,
661 arg_type,
662 result);
663 }
664
665 return result_count;
666 }
667
668 /* A helper for value_dynamic_cast. This implements the second of two
669 runtime checks: we look for a unique public sibling class of the
670 argument's declared class. */
671
672 static int
673 dynamic_cast_check_2 (struct type *desired_type,
674 const gdb_byte *valaddr,
675 LONGEST embedded_offset,
676 CORE_ADDR address,
677 struct value *val,
678 struct type *search_type,
679 struct value **result)
680 {
681 int i, result_count = 0;
682
683 for (i = 0; i < TYPE_N_BASECLASSES (search_type) && result_count < 2; ++i)
684 {
685 LONGEST offset;
686
687 if (! BASETYPE_VIA_PUBLIC (search_type, i))
688 continue;
689
690 offset = baseclass_offset (search_type, i, valaddr, embedded_offset,
691 address, val);
692 if (class_types_same_p (desired_type, TYPE_BASECLASS (search_type, i)))
693 {
694 ++result_count;
695 if (*result == NULL)
696 *result = value_at_lazy (TYPE_BASECLASS (search_type, i),
697 address + embedded_offset + offset);
698 }
699 else
700 result_count += dynamic_cast_check_2 (desired_type,
701 valaddr,
702 embedded_offset + offset,
703 address, val,
704 TYPE_BASECLASS (search_type, i),
705 result);
706 }
707
708 return result_count;
709 }
710
711 /* The C++ dynamic_cast operator. */
712
713 struct value *
714 value_dynamic_cast (struct type *type, struct value *arg)
715 {
716 int full, using_enc;
717 LONGEST top;
718 struct type *resolved_type = check_typedef (type);
719 struct type *arg_type = check_typedef (value_type (arg));
720 struct type *class_type, *rtti_type;
721 struct value *result, *tem, *original_arg = arg;
722 CORE_ADDR addr;
723 int is_ref = TYPE_IS_REFERENCE (resolved_type);
724
725 if (resolved_type->code () != TYPE_CODE_PTR
726 && !TYPE_IS_REFERENCE (resolved_type))
727 error (_("Argument to dynamic_cast must be a pointer or reference type"));
728 if (TYPE_TARGET_TYPE (resolved_type)->code () != TYPE_CODE_VOID
729 && TYPE_TARGET_TYPE (resolved_type)->code () != TYPE_CODE_STRUCT)
730 error (_("Argument to dynamic_cast must be pointer to class or `void *'"));
731
732 class_type = check_typedef (TYPE_TARGET_TYPE (resolved_type));
733 if (resolved_type->code () == TYPE_CODE_PTR)
734 {
735 if (arg_type->code () != TYPE_CODE_PTR
736 && ! (arg_type->code () == TYPE_CODE_INT
737 && value_as_long (arg) == 0))
738 error (_("Argument to dynamic_cast does not have pointer type"));
739 if (arg_type->code () == TYPE_CODE_PTR)
740 {
741 arg_type = check_typedef (TYPE_TARGET_TYPE (arg_type));
742 if (arg_type->code () != TYPE_CODE_STRUCT)
743 error (_("Argument to dynamic_cast does "
744 "not have pointer to class type"));
745 }
746
747 /* Handle NULL pointers. */
748 if (value_as_long (arg) == 0)
749 return value_zero (type, not_lval);
750
751 arg = value_ind (arg);
752 }
753 else
754 {
755 if (arg_type->code () != TYPE_CODE_STRUCT)
756 error (_("Argument to dynamic_cast does not have class type"));
757 }
758
759 /* If the classes are the same, just return the argument. */
760 if (class_types_same_p (class_type, arg_type))
761 return value_cast (type, arg);
762
763 /* If the target type is a unique base class of the argument's
764 declared type, just cast it. */
765 if (is_ancestor (class_type, arg_type))
766 {
767 if (is_unique_ancestor (class_type, arg))
768 return value_cast (type, original_arg);
769 error (_("Ambiguous dynamic_cast"));
770 }
771
772 rtti_type = value_rtti_type (arg, &full, &top, &using_enc);
773 if (! rtti_type)
774 error (_("Couldn't determine value's most derived type for dynamic_cast"));
775
776 /* Compute the most derived object's address. */
777 addr = value_address (arg);
778 if (full)
779 {
780 /* Done. */
781 }
782 else if (using_enc)
783 addr += top;
784 else
785 addr += top + value_embedded_offset (arg);
786
787 /* dynamic_cast<void *> means to return a pointer to the
788 most-derived object. */
789 if (resolved_type->code () == TYPE_CODE_PTR
790 && TYPE_TARGET_TYPE (resolved_type)->code () == TYPE_CODE_VOID)
791 return value_at_lazy (type, addr);
792
793 tem = value_at (type, addr);
794 type = value_type (tem);
795
796 /* The first dynamic check specified in 5.2.7. */
797 if (is_public_ancestor (arg_type, TYPE_TARGET_TYPE (resolved_type)))
798 {
799 if (class_types_same_p (rtti_type, TYPE_TARGET_TYPE (resolved_type)))
800 return tem;
801 result = NULL;
802 if (dynamic_cast_check_1 (TYPE_TARGET_TYPE (resolved_type),
803 value_contents_for_printing (tem),
804 value_embedded_offset (tem),
805 value_address (tem), tem,
806 rtti_type, addr,
807 arg_type,
808 &result) == 1)
809 return value_cast (type,
810 is_ref
811 ? value_ref (result, resolved_type->code ())
812 : value_addr (result));
813 }
814
815 /* The second dynamic check specified in 5.2.7. */
816 result = NULL;
817 if (is_public_ancestor (arg_type, rtti_type)
818 && dynamic_cast_check_2 (TYPE_TARGET_TYPE (resolved_type),
819 value_contents_for_printing (tem),
820 value_embedded_offset (tem),
821 value_address (tem), tem,
822 rtti_type, &result) == 1)
823 return value_cast (type,
824 is_ref
825 ? value_ref (result, resolved_type->code ())
826 : value_addr (result));
827
828 if (resolved_type->code () == TYPE_CODE_PTR)
829 return value_zero (type, not_lval);
830
831 error (_("dynamic_cast failed"));
832 }
833
834 /* Create a value of type TYPE that is zero, and return it. */
835
836 struct value *
837 value_zero (struct type *type, enum lval_type lv)
838 {
839 struct value *val = allocate_value (type);
840
841 VALUE_LVAL (val) = (lv == lval_computed ? not_lval : lv);
842 return val;
843 }
844
845 /* Create a not_lval value of numeric type TYPE that is one, and return it. */
846
847 struct value *
848 value_one (struct type *type)
849 {
850 struct type *type1 = check_typedef (type);
851 struct value *val;
852
853 if (is_integral_type (type1) || is_floating_type (type1))
854 {
855 val = value_from_longest (type, (LONGEST) 1);
856 }
857 else if (type1->code () == TYPE_CODE_ARRAY && TYPE_VECTOR (type1))
858 {
859 struct type *eltype = check_typedef (TYPE_TARGET_TYPE (type1));
860 int i;
861 LONGEST low_bound, high_bound;
862 struct value *tmp;
863
864 if (!get_array_bounds (type1, &low_bound, &high_bound))
865 error (_("Could not determine the vector bounds"));
866
867 val = allocate_value (type);
868 for (i = 0; i < high_bound - low_bound + 1; i++)
869 {
870 tmp = value_one (eltype);
871 memcpy (value_contents_writeable (val) + i * TYPE_LENGTH (eltype),
872 value_contents_all (tmp), TYPE_LENGTH (eltype));
873 }
874 }
875 else
876 {
877 error (_("Not a numeric type."));
878 }
879
880 /* value_one result is never used for assignments to. */
881 gdb_assert (VALUE_LVAL (val) == not_lval);
882
883 return val;
884 }
885
886 /* Helper function for value_at, value_at_lazy, and value_at_lazy_stack.
887 The type of the created value may differ from the passed type TYPE.
888 Make sure to retrieve the returned values's new type after this call
889 e.g. in case the type is a variable length array. */
890
891 static struct value *
892 get_value_at (struct type *type, CORE_ADDR addr, int lazy)
893 {
894 struct value *val;
895
896 if (check_typedef (type)->code () == TYPE_CODE_VOID)
897 error (_("Attempt to dereference a generic pointer."));
898
899 val = value_from_contents_and_address (type, NULL, addr);
900
901 if (!lazy)
902 value_fetch_lazy (val);
903
904 return val;
905 }
906
907 /* Return a value with type TYPE located at ADDR.
908
909 Call value_at only if the data needs to be fetched immediately;
910 if we can be 'lazy' and defer the fetch, perhaps indefinitely, call
911 value_at_lazy instead. value_at_lazy simply records the address of
912 the data and sets the lazy-evaluation-required flag. The lazy flag
913 is tested in the value_contents macro, which is used if and when
914 the contents are actually required. The type of the created value
915 may differ from the passed type TYPE. Make sure to retrieve the
916 returned values's new type after this call e.g. in case the type
917 is a variable length array.
918
919 Note: value_at does *NOT* handle embedded offsets; perform such
920 adjustments before or after calling it. */
921
922 struct value *
923 value_at (struct type *type, CORE_ADDR addr)
924 {
925 return get_value_at (type, addr, 0);
926 }
927
928 /* Return a lazy value with type TYPE located at ADDR (cf. value_at).
929 The type of the created value may differ from the passed type TYPE.
930 Make sure to retrieve the returned values's new type after this call
931 e.g. in case the type is a variable length array. */
932
933 struct value *
934 value_at_lazy (struct type *type, CORE_ADDR addr)
935 {
936 return get_value_at (type, addr, 1);
937 }
938
939 void
940 read_value_memory (struct value *val, LONGEST bit_offset,
941 int stack, CORE_ADDR memaddr,
942 gdb_byte *buffer, size_t length)
943 {
944 ULONGEST xfered_total = 0;
945 struct gdbarch *arch = get_value_arch (val);
946 int unit_size = gdbarch_addressable_memory_unit_size (arch);
947 enum target_object object;
948
949 object = stack ? TARGET_OBJECT_STACK_MEMORY : TARGET_OBJECT_MEMORY;
950
951 while (xfered_total < length)
952 {
953 enum target_xfer_status status;
954 ULONGEST xfered_partial;
955
956 status = target_xfer_partial (current_top_target (),
957 object, NULL,
958 buffer + xfered_total * unit_size, NULL,
959 memaddr + xfered_total,
960 length - xfered_total,
961 &xfered_partial);
962
963 if (status == TARGET_XFER_OK)
964 /* nothing */;
965 else if (status == TARGET_XFER_UNAVAILABLE)
966 mark_value_bits_unavailable (val, (xfered_total * HOST_CHAR_BIT
967 + bit_offset),
968 xfered_partial * HOST_CHAR_BIT);
969 else if (status == TARGET_XFER_EOF)
970 memory_error (TARGET_XFER_E_IO, memaddr + xfered_total);
971 else
972 memory_error (status, memaddr + xfered_total);
973
974 xfered_total += xfered_partial;
975 QUIT;
976 }
977 }
978
979 /* Store the contents of FROMVAL into the location of TOVAL.
980 Return a new value with the location of TOVAL and contents of FROMVAL. */
981
982 struct value *
983 value_assign (struct value *toval, struct value *fromval)
984 {
985 struct type *type;
986 struct value *val;
987 struct frame_id old_frame;
988
989 if (!deprecated_value_modifiable (toval))
990 error (_("Left operand of assignment is not a modifiable lvalue."));
991
992 toval = coerce_ref (toval);
993
994 type = value_type (toval);
995 if (VALUE_LVAL (toval) != lval_internalvar)
996 fromval = value_cast (type, fromval);
997 else
998 {
999 /* Coerce arrays and functions to pointers, except for arrays
1000 which only live in GDB's storage. */
1001 if (!value_must_coerce_to_target (fromval))
1002 fromval = coerce_array (fromval);
1003 }
1004
1005 type = check_typedef (type);
1006
1007 /* Since modifying a register can trash the frame chain, and
1008 modifying memory can trash the frame cache, we save the old frame
1009 and then restore the new frame afterwards. */
1010 old_frame = get_frame_id (deprecated_safe_get_selected_frame ());
1011
1012 switch (VALUE_LVAL (toval))
1013 {
1014 case lval_internalvar:
1015 set_internalvar (VALUE_INTERNALVAR (toval), fromval);
1016 return value_of_internalvar (get_type_arch (type),
1017 VALUE_INTERNALVAR (toval));
1018
1019 case lval_internalvar_component:
1020 {
1021 LONGEST offset = value_offset (toval);
1022
1023 /* Are we dealing with a bitfield?
1024
1025 It is important to mention that `value_parent (toval)' is
1026 non-NULL iff `value_bitsize (toval)' is non-zero. */
1027 if (value_bitsize (toval))
1028 {
1029 /* VALUE_INTERNALVAR below refers to the parent value, while
1030 the offset is relative to this parent value. */
1031 gdb_assert (value_parent (value_parent (toval)) == NULL);
1032 offset += value_offset (value_parent (toval));
1033 }
1034
1035 set_internalvar_component (VALUE_INTERNALVAR (toval),
1036 offset,
1037 value_bitpos (toval),
1038 value_bitsize (toval),
1039 fromval);
1040 }
1041 break;
1042
1043 case lval_memory:
1044 {
1045 const gdb_byte *dest_buffer;
1046 CORE_ADDR changed_addr;
1047 int changed_len;
1048 gdb_byte buffer[sizeof (LONGEST)];
1049
1050 if (value_bitsize (toval))
1051 {
1052 struct value *parent = value_parent (toval);
1053
1054 changed_addr = value_address (parent) + value_offset (toval);
1055 changed_len = (value_bitpos (toval)
1056 + value_bitsize (toval)
1057 + HOST_CHAR_BIT - 1)
1058 / HOST_CHAR_BIT;
1059
1060 /* If we can read-modify-write exactly the size of the
1061 containing type (e.g. short or int) then do so. This
1062 is safer for volatile bitfields mapped to hardware
1063 registers. */
1064 if (changed_len < TYPE_LENGTH (type)
1065 && TYPE_LENGTH (type) <= (int) sizeof (LONGEST)
1066 && ((LONGEST) changed_addr % TYPE_LENGTH (type)) == 0)
1067 changed_len = TYPE_LENGTH (type);
1068
1069 if (changed_len > (int) sizeof (LONGEST))
1070 error (_("Can't handle bitfields which "
1071 "don't fit in a %d bit word."),
1072 (int) sizeof (LONGEST) * HOST_CHAR_BIT);
1073
1074 read_memory (changed_addr, buffer, changed_len);
1075 modify_field (type, buffer, value_as_long (fromval),
1076 value_bitpos (toval), value_bitsize (toval));
1077 dest_buffer = buffer;
1078 }
1079 else
1080 {
1081 changed_addr = value_address (toval);
1082 changed_len = type_length_units (type);
1083 dest_buffer = value_contents (fromval);
1084 }
1085
1086 write_memory_with_notification (changed_addr, dest_buffer, changed_len);
1087 }
1088 break;
1089
1090 case lval_register:
1091 {
1092 struct frame_info *frame;
1093 struct gdbarch *gdbarch;
1094 int value_reg;
1095
1096 /* Figure out which frame this is in currently.
1097
1098 We use VALUE_FRAME_ID for obtaining the value's frame id instead of
1099 VALUE_NEXT_FRAME_ID due to requiring a frame which may be passed to
1100 put_frame_register_bytes() below. That function will (eventually)
1101 perform the necessary unwind operation by first obtaining the next
1102 frame. */
1103 frame = frame_find_by_id (VALUE_FRAME_ID (toval));
1104
1105 value_reg = VALUE_REGNUM (toval);
1106
1107 if (!frame)
1108 error (_("Value being assigned to is no longer active."));
1109
1110 gdbarch = get_frame_arch (frame);
1111
1112 if (value_bitsize (toval))
1113 {
1114 struct value *parent = value_parent (toval);
1115 LONGEST offset = value_offset (parent) + value_offset (toval);
1116 int changed_len;
1117 gdb_byte buffer[sizeof (LONGEST)];
1118 int optim, unavail;
1119
1120 changed_len = (value_bitpos (toval)
1121 + value_bitsize (toval)
1122 + HOST_CHAR_BIT - 1)
1123 / HOST_CHAR_BIT;
1124
1125 if (changed_len > (int) sizeof (LONGEST))
1126 error (_("Can't handle bitfields which "
1127 "don't fit in a %d bit word."),
1128 (int) sizeof (LONGEST) * HOST_CHAR_BIT);
1129
1130 if (!get_frame_register_bytes (frame, value_reg, offset,
1131 changed_len, buffer,
1132 &optim, &unavail))
1133 {
1134 if (optim)
1135 throw_error (OPTIMIZED_OUT_ERROR,
1136 _("value has been optimized out"));
1137 if (unavail)
1138 throw_error (NOT_AVAILABLE_ERROR,
1139 _("value is not available"));
1140 }
1141
1142 modify_field (type, buffer, value_as_long (fromval),
1143 value_bitpos (toval), value_bitsize (toval));
1144
1145 put_frame_register_bytes (frame, value_reg, offset,
1146 changed_len, buffer);
1147 }
1148 else
1149 {
1150 if (gdbarch_convert_register_p (gdbarch, VALUE_REGNUM (toval),
1151 type))
1152 {
1153 /* If TOVAL is a special machine register requiring
1154 conversion of program values to a special raw
1155 format. */
1156 gdbarch_value_to_register (gdbarch, frame,
1157 VALUE_REGNUM (toval), type,
1158 value_contents (fromval));
1159 }
1160 else
1161 {
1162 put_frame_register_bytes (frame, value_reg,
1163 value_offset (toval),
1164 TYPE_LENGTH (type),
1165 value_contents (fromval));
1166 }
1167 }
1168
1169 gdb::observers::register_changed.notify (frame, value_reg);
1170 break;
1171 }
1172
1173 case lval_computed:
1174 {
1175 const struct lval_funcs *funcs = value_computed_funcs (toval);
1176
1177 if (funcs->write != NULL)
1178 {
1179 funcs->write (toval, fromval);
1180 break;
1181 }
1182 }
1183 /* Fall through. */
1184
1185 default:
1186 error (_("Left operand of assignment is not an lvalue."));
1187 }
1188
1189 /* Assigning to the stack pointer, frame pointer, and other
1190 (architecture and calling convention specific) registers may
1191 cause the frame cache and regcache to be out of date. Assigning to memory
1192 also can. We just do this on all assignments to registers or
1193 memory, for simplicity's sake; I doubt the slowdown matters. */
1194 switch (VALUE_LVAL (toval))
1195 {
1196 case lval_memory:
1197 case lval_register:
1198 case lval_computed:
1199
1200 gdb::observers::target_changed.notify (current_top_target ());
1201
1202 /* Having destroyed the frame cache, restore the selected
1203 frame. */
1204
1205 /* FIXME: cagney/2002-11-02: There has to be a better way of
1206 doing this. Instead of constantly saving/restoring the
1207 frame. Why not create a get_selected_frame() function that,
1208 having saved the selected frame's ID can automatically
1209 re-find the previously selected frame automatically. */
1210
1211 {
1212 struct frame_info *fi = frame_find_by_id (old_frame);
1213
1214 if (fi != NULL)
1215 select_frame (fi);
1216 }
1217
1218 break;
1219 default:
1220 break;
1221 }
1222
1223 /* If the field does not entirely fill a LONGEST, then zero the sign
1224 bits. If the field is signed, and is negative, then sign
1225 extend. */
1226 if ((value_bitsize (toval) > 0)
1227 && (value_bitsize (toval) < 8 * (int) sizeof (LONGEST)))
1228 {
1229 LONGEST fieldval = value_as_long (fromval);
1230 LONGEST valmask = (((ULONGEST) 1) << value_bitsize (toval)) - 1;
1231
1232 fieldval &= valmask;
1233 if (!TYPE_UNSIGNED (type)
1234 && (fieldval & (valmask ^ (valmask >> 1))))
1235 fieldval |= ~valmask;
1236
1237 fromval = value_from_longest (type, fieldval);
1238 }
1239
1240 /* The return value is a copy of TOVAL so it shares its location
1241 information, but its contents are updated from FROMVAL. This
1242 implies the returned value is not lazy, even if TOVAL was. */
1243 val = value_copy (toval);
1244 set_value_lazy (val, 0);
1245 memcpy (value_contents_raw (val), value_contents (fromval),
1246 TYPE_LENGTH (type));
1247
1248 /* We copy over the enclosing type and pointed-to offset from FROMVAL
1249 in the case of pointer types. For object types, the enclosing type
1250 and embedded offset must *not* be copied: the target object refered
1251 to by TOVAL retains its original dynamic type after assignment. */
1252 if (type->code () == TYPE_CODE_PTR)
1253 {
1254 set_value_enclosing_type (val, value_enclosing_type (fromval));
1255 set_value_pointed_to_offset (val, value_pointed_to_offset (fromval));
1256 }
1257
1258 return val;
1259 }
1260
1261 /* Extend a value VAL to COUNT repetitions of its type. */
1262
1263 struct value *
1264 value_repeat (struct value *arg1, int count)
1265 {
1266 struct value *val;
1267
1268 if (VALUE_LVAL (arg1) != lval_memory)
1269 error (_("Only values in memory can be extended with '@'."));
1270 if (count < 1)
1271 error (_("Invalid number %d of repetitions."), count);
1272
1273 val = allocate_repeat_value (value_enclosing_type (arg1), count);
1274
1275 VALUE_LVAL (val) = lval_memory;
1276 set_value_address (val, value_address (arg1));
1277
1278 read_value_memory (val, 0, value_stack (val), value_address (val),
1279 value_contents_all_raw (val),
1280 type_length_units (value_enclosing_type (val)));
1281
1282 return val;
1283 }
1284
1285 struct value *
1286 value_of_variable (struct symbol *var, const struct block *b)
1287 {
1288 struct frame_info *frame = NULL;
1289
1290 if (symbol_read_needs_frame (var))
1291 frame = get_selected_frame (_("No frame selected."));
1292
1293 return read_var_value (var, b, frame);
1294 }
1295
1296 struct value *
1297 address_of_variable (struct symbol *var, const struct block *b)
1298 {
1299 struct type *type = SYMBOL_TYPE (var);
1300 struct value *val;
1301
1302 /* Evaluate it first; if the result is a memory address, we're fine.
1303 Lazy evaluation pays off here. */
1304
1305 val = value_of_variable (var, b);
1306 type = value_type (val);
1307
1308 if ((VALUE_LVAL (val) == lval_memory && value_lazy (val))
1309 || type->code () == TYPE_CODE_FUNC)
1310 {
1311 CORE_ADDR addr = value_address (val);
1312
1313 return value_from_pointer (lookup_pointer_type (type), addr);
1314 }
1315
1316 /* Not a memory address; check what the problem was. */
1317 switch (VALUE_LVAL (val))
1318 {
1319 case lval_register:
1320 {
1321 struct frame_info *frame;
1322 const char *regname;
1323
1324 frame = frame_find_by_id (VALUE_NEXT_FRAME_ID (val));
1325 gdb_assert (frame);
1326
1327 regname = gdbarch_register_name (get_frame_arch (frame),
1328 VALUE_REGNUM (val));
1329 gdb_assert (regname && *regname);
1330
1331 error (_("Address requested for identifier "
1332 "\"%s\" which is in register $%s"),
1333 var->print_name (), regname);
1334 break;
1335 }
1336
1337 default:
1338 error (_("Can't take address of \"%s\" which isn't an lvalue."),
1339 var->print_name ());
1340 break;
1341 }
1342
1343 return val;
1344 }
1345
1346 /* See value.h. */
1347
1348 bool
1349 value_must_coerce_to_target (struct value *val)
1350 {
1351 struct type *valtype;
1352
1353 /* The only lval kinds which do not live in target memory. */
1354 if (VALUE_LVAL (val) != not_lval
1355 && VALUE_LVAL (val) != lval_internalvar
1356 && VALUE_LVAL (val) != lval_xcallable)
1357 return false;
1358
1359 valtype = check_typedef (value_type (val));
1360
1361 switch (valtype->code ())
1362 {
1363 case TYPE_CODE_ARRAY:
1364 return TYPE_VECTOR (valtype) ? 0 : 1;
1365 case TYPE_CODE_STRING:
1366 return true;
1367 default:
1368 return false;
1369 }
1370 }
1371
1372 /* Make sure that VAL lives in target memory if it's supposed to. For
1373 instance, strings are constructed as character arrays in GDB's
1374 storage, and this function copies them to the target. */
1375
1376 struct value *
1377 value_coerce_to_target (struct value *val)
1378 {
1379 LONGEST length;
1380 CORE_ADDR addr;
1381
1382 if (!value_must_coerce_to_target (val))
1383 return val;
1384
1385 length = TYPE_LENGTH (check_typedef (value_type (val)));
1386 addr = allocate_space_in_inferior (length);
1387 write_memory (addr, value_contents (val), length);
1388 return value_at_lazy (value_type (val), addr);
1389 }
1390
1391 /* Given a value which is an array, return a value which is a pointer
1392 to its first element, regardless of whether or not the array has a
1393 nonzero lower bound.
1394
1395 FIXME: A previous comment here indicated that this routine should
1396 be substracting the array's lower bound. It's not clear to me that
1397 this is correct. Given an array subscripting operation, it would
1398 certainly work to do the adjustment here, essentially computing:
1399
1400 (&array[0] - (lowerbound * sizeof array[0])) + (index * sizeof array[0])
1401
1402 However I believe a more appropriate and logical place to account
1403 for the lower bound is to do so in value_subscript, essentially
1404 computing:
1405
1406 (&array[0] + ((index - lowerbound) * sizeof array[0]))
1407
1408 As further evidence consider what would happen with operations
1409 other than array subscripting, where the caller would get back a
1410 value that had an address somewhere before the actual first element
1411 of the array, and the information about the lower bound would be
1412 lost because of the coercion to pointer type. */
1413
1414 struct value *
1415 value_coerce_array (struct value *arg1)
1416 {
1417 struct type *type = check_typedef (value_type (arg1));
1418
1419 /* If the user tries to do something requiring a pointer with an
1420 array that has not yet been pushed to the target, then this would
1421 be a good time to do so. */
1422 arg1 = value_coerce_to_target (arg1);
1423
1424 if (VALUE_LVAL (arg1) != lval_memory)
1425 error (_("Attempt to take address of value not located in memory."));
1426
1427 return value_from_pointer (lookup_pointer_type (TYPE_TARGET_TYPE (type)),
1428 value_address (arg1));
1429 }
1430
1431 /* Given a value which is a function, return a value which is a pointer
1432 to it. */
1433
1434 struct value *
1435 value_coerce_function (struct value *arg1)
1436 {
1437 struct value *retval;
1438
1439 if (VALUE_LVAL (arg1) != lval_memory)
1440 error (_("Attempt to take address of value not located in memory."));
1441
1442 retval = value_from_pointer (lookup_pointer_type (value_type (arg1)),
1443 value_address (arg1));
1444 return retval;
1445 }
1446
1447 /* Return a pointer value for the object for which ARG1 is the
1448 contents. */
1449
1450 struct value *
1451 value_addr (struct value *arg1)
1452 {
1453 struct value *arg2;
1454 struct type *type = check_typedef (value_type (arg1));
1455
1456 if (TYPE_IS_REFERENCE (type))
1457 {
1458 if (value_bits_synthetic_pointer (arg1, value_embedded_offset (arg1),
1459 TARGET_CHAR_BIT * TYPE_LENGTH (type)))
1460 arg1 = coerce_ref (arg1);
1461 else
1462 {
1463 /* Copy the value, but change the type from (T&) to (T*). We
1464 keep the same location information, which is efficient, and
1465 allows &(&X) to get the location containing the reference.
1466 Do the same to its enclosing type for consistency. */
1467 struct type *type_ptr
1468 = lookup_pointer_type (TYPE_TARGET_TYPE (type));
1469 struct type *enclosing_type
1470 = check_typedef (value_enclosing_type (arg1));
1471 struct type *enclosing_type_ptr
1472 = lookup_pointer_type (TYPE_TARGET_TYPE (enclosing_type));
1473
1474 arg2 = value_copy (arg1);
1475 deprecated_set_value_type (arg2, type_ptr);
1476 set_value_enclosing_type (arg2, enclosing_type_ptr);
1477
1478 return arg2;
1479 }
1480 }
1481 if (type->code () == TYPE_CODE_FUNC)
1482 return value_coerce_function (arg1);
1483
1484 /* If this is an array that has not yet been pushed to the target,
1485 then this would be a good time to force it to memory. */
1486 arg1 = value_coerce_to_target (arg1);
1487
1488 if (VALUE_LVAL (arg1) != lval_memory)
1489 error (_("Attempt to take address of value not located in memory."));
1490
1491 /* Get target memory address. */
1492 arg2 = value_from_pointer (lookup_pointer_type (value_type (arg1)),
1493 (value_address (arg1)
1494 + value_embedded_offset (arg1)));
1495
1496 /* This may be a pointer to a base subobject; so remember the
1497 full derived object's type ... */
1498 set_value_enclosing_type (arg2,
1499 lookup_pointer_type (value_enclosing_type (arg1)));
1500 /* ... and also the relative position of the subobject in the full
1501 object. */
1502 set_value_pointed_to_offset (arg2, value_embedded_offset (arg1));
1503 return arg2;
1504 }
1505
1506 /* Return a reference value for the object for which ARG1 is the
1507 contents. */
1508
1509 struct value *
1510 value_ref (struct value *arg1, enum type_code refcode)
1511 {
1512 struct value *arg2;
1513 struct type *type = check_typedef (value_type (arg1));
1514
1515 gdb_assert (refcode == TYPE_CODE_REF || refcode == TYPE_CODE_RVALUE_REF);
1516
1517 if ((type->code () == TYPE_CODE_REF
1518 || type->code () == TYPE_CODE_RVALUE_REF)
1519 && type->code () == refcode)
1520 return arg1;
1521
1522 arg2 = value_addr (arg1);
1523 deprecated_set_value_type (arg2, lookup_reference_type (type, refcode));
1524 return arg2;
1525 }
1526
1527 /* Given a value of a pointer type, apply the C unary * operator to
1528 it. */
1529
1530 struct value *
1531 value_ind (struct value *arg1)
1532 {
1533 struct type *base_type;
1534 struct value *arg2;
1535
1536 arg1 = coerce_array (arg1);
1537
1538 base_type = check_typedef (value_type (arg1));
1539
1540 if (VALUE_LVAL (arg1) == lval_computed)
1541 {
1542 const struct lval_funcs *funcs = value_computed_funcs (arg1);
1543
1544 if (funcs->indirect)
1545 {
1546 struct value *result = funcs->indirect (arg1);
1547
1548 if (result)
1549 return result;
1550 }
1551 }
1552
1553 if (base_type->code () == TYPE_CODE_PTR)
1554 {
1555 struct type *enc_type;
1556
1557 /* We may be pointing to something embedded in a larger object.
1558 Get the real type of the enclosing object. */
1559 enc_type = check_typedef (value_enclosing_type (arg1));
1560 enc_type = TYPE_TARGET_TYPE (enc_type);
1561
1562 CORE_ADDR base_addr;
1563 if (check_typedef (enc_type)->code () == TYPE_CODE_FUNC
1564 || check_typedef (enc_type)->code () == TYPE_CODE_METHOD)
1565 {
1566 /* For functions, go through find_function_addr, which knows
1567 how to handle function descriptors. */
1568 base_addr = find_function_addr (arg1, NULL);
1569 }
1570 else
1571 {
1572 /* Retrieve the enclosing object pointed to. */
1573 base_addr = (value_as_address (arg1)
1574 - value_pointed_to_offset (arg1));
1575 }
1576 arg2 = value_at_lazy (enc_type, base_addr);
1577 enc_type = value_type (arg2);
1578 return readjust_indirect_value_type (arg2, enc_type, base_type,
1579 arg1, base_addr);
1580 }
1581
1582 error (_("Attempt to take contents of a non-pointer value."));
1583 }
1584
1585 /* Create a value for an array by allocating space in GDB, copying the
1587 data into that space, and then setting up an array value.
1588
1589 The array bounds are set from LOWBOUND and HIGHBOUND, and the array
1590 is populated from the values passed in ELEMVEC.
1591
1592 The element type of the array is inherited from the type of the
1593 first element, and all elements must have the same size (though we
1594 don't currently enforce any restriction on their types). */
1595
1596 struct value *
1597 value_array (int lowbound, int highbound, struct value **elemvec)
1598 {
1599 int nelem;
1600 int idx;
1601 ULONGEST typelength;
1602 struct value *val;
1603 struct type *arraytype;
1604
1605 /* Validate that the bounds are reasonable and that each of the
1606 elements have the same size. */
1607
1608 nelem = highbound - lowbound + 1;
1609 if (nelem <= 0)
1610 {
1611 error (_("bad array bounds (%d, %d)"), lowbound, highbound);
1612 }
1613 typelength = type_length_units (value_enclosing_type (elemvec[0]));
1614 for (idx = 1; idx < nelem; idx++)
1615 {
1616 if (type_length_units (value_enclosing_type (elemvec[idx]))
1617 != typelength)
1618 {
1619 error (_("array elements must all be the same size"));
1620 }
1621 }
1622
1623 arraytype = lookup_array_range_type (value_enclosing_type (elemvec[0]),
1624 lowbound, highbound);
1625
1626 if (!current_language->c_style_arrays)
1627 {
1628 val = allocate_value (arraytype);
1629 for (idx = 0; idx < nelem; idx++)
1630 value_contents_copy (val, idx * typelength, elemvec[idx], 0,
1631 typelength);
1632 return val;
1633 }
1634
1635 /* Allocate space to store the array, and then initialize it by
1636 copying in each element. */
1637
1638 val = allocate_value (arraytype);
1639 for (idx = 0; idx < nelem; idx++)
1640 value_contents_copy (val, idx * typelength, elemvec[idx], 0, typelength);
1641 return val;
1642 }
1643
1644 struct value *
1645 value_cstring (const char *ptr, ssize_t len, struct type *char_type)
1646 {
1647 struct value *val;
1648 int lowbound = current_language->string_lower_bound;
1649 ssize_t highbound = len / TYPE_LENGTH (char_type);
1650 struct type *stringtype
1651 = lookup_array_range_type (char_type, lowbound, highbound + lowbound - 1);
1652
1653 val = allocate_value (stringtype);
1654 memcpy (value_contents_raw (val), ptr, len);
1655 return val;
1656 }
1657
1658 /* Create a value for a string constant by allocating space in the
1659 inferior, copying the data into that space, and returning the
1660 address with type TYPE_CODE_STRING. PTR points to the string
1661 constant data; LEN is number of characters.
1662
1663 Note that string types are like array of char types with a lower
1664 bound of zero and an upper bound of LEN - 1. Also note that the
1665 string may contain embedded null bytes. */
1666
1667 struct value *
1668 value_string (const char *ptr, ssize_t len, struct type *char_type)
1669 {
1670 struct value *val;
1671 int lowbound = current_language->string_lower_bound;
1672 ssize_t highbound = len / TYPE_LENGTH (char_type);
1673 struct type *stringtype
1674 = lookup_string_range_type (char_type, lowbound, highbound + lowbound - 1);
1675
1676 val = allocate_value (stringtype);
1677 memcpy (value_contents_raw (val), ptr, len);
1678 return val;
1679 }
1680
1681
1682 /* See if we can pass arguments in T2 to a function which takes
1684 arguments of types T1. T1 is a list of NARGS arguments, and T2 is
1685 a NULL-terminated vector. If some arguments need coercion of some
1686 sort, then the coerced values are written into T2. Return value is
1687 0 if the arguments could be matched, or the position at which they
1688 differ if not.
1689
1690 STATICP is nonzero if the T1 argument list came from a static
1691 member function. T2 will still include the ``this'' pointer, but
1692 it will be skipped.
1693
1694 For non-static member functions, we ignore the first argument,
1695 which is the type of the instance variable. This is because we
1696 want to handle calls with objects from derived classes. This is
1697 not entirely correct: we should actually check to make sure that a
1698 requested operation is type secure, shouldn't we? FIXME. */
1699
1700 static int
1701 typecmp (int staticp, int varargs, int nargs,
1702 struct field t1[], struct value *t2[])
1703 {
1704 int i;
1705
1706 if (t2 == 0)
1707 internal_error (__FILE__, __LINE__,
1708 _("typecmp: no argument list"));
1709
1710 /* Skip ``this'' argument if applicable. T2 will always include
1711 THIS. */
1712 if (staticp)
1713 t2 ++;
1714
1715 for (i = 0;
1716 (i < nargs) && t1[i].type ()->code () != TYPE_CODE_VOID;
1717 i++)
1718 {
1719 struct type *tt1, *tt2;
1720
1721 if (!t2[i])
1722 return i + 1;
1723
1724 tt1 = check_typedef (t1[i].type ());
1725 tt2 = check_typedef (value_type (t2[i]));
1726
1727 if (TYPE_IS_REFERENCE (tt1)
1728 /* We should be doing hairy argument matching, as below. */
1729 && (check_typedef (TYPE_TARGET_TYPE (tt1))->code ()
1730 == tt2->code ()))
1731 {
1732 if (tt2->code () == TYPE_CODE_ARRAY)
1733 t2[i] = value_coerce_array (t2[i]);
1734 else
1735 t2[i] = value_ref (t2[i], tt1->code ());
1736 continue;
1737 }
1738
1739 /* djb - 20000715 - Until the new type structure is in the
1740 place, and we can attempt things like implicit conversions,
1741 we need to do this so you can take something like a map<const
1742 char *>, and properly access map["hello"], because the
1743 argument to [] will be a reference to a pointer to a char,
1744 and the argument will be a pointer to a char. */
1745 while (TYPE_IS_REFERENCE (tt1) || tt1->code () == TYPE_CODE_PTR)
1746 {
1747 tt1 = check_typedef ( TYPE_TARGET_TYPE (tt1) );
1748 }
1749 while (tt2->code () == TYPE_CODE_ARRAY
1750 || tt2->code () == TYPE_CODE_PTR
1751 || TYPE_IS_REFERENCE (tt2))
1752 {
1753 tt2 = check_typedef (TYPE_TARGET_TYPE (tt2));
1754 }
1755 if (tt1->code () == tt2->code ())
1756 continue;
1757 /* Array to pointer is a `trivial conversion' according to the
1758 ARM. */
1759
1760 /* We should be doing much hairier argument matching (see
1761 section 13.2 of the ARM), but as a quick kludge, just check
1762 for the same type code. */
1763 if (t1[i].type ()->code () != value_type (t2[i])->code ())
1764 return i + 1;
1765 }
1766 if (varargs || t2[i] == NULL)
1767 return 0;
1768 return i + 1;
1769 }
1770
1771 /* Helper class for do_search_struct_field that updates *RESULT_PTR
1772 and *LAST_BOFFSET, and possibly throws an exception if the field
1773 search has yielded ambiguous results. */
1774
1775 static void
1776 update_search_result (struct value **result_ptr, struct value *v,
1777 LONGEST *last_boffset, LONGEST boffset,
1778 const char *name, struct type *type)
1779 {
1780 if (v != NULL)
1781 {
1782 if (*result_ptr != NULL
1783 /* The result is not ambiguous if all the classes that are
1784 found occupy the same space. */
1785 && *last_boffset != boffset)
1786 error (_("base class '%s' is ambiguous in type '%s'"),
1787 name, TYPE_SAFE_NAME (type));
1788 *result_ptr = v;
1789 *last_boffset = boffset;
1790 }
1791 }
1792
1793 /* A helper for search_struct_field. This does all the work; most
1794 arguments are as passed to search_struct_field. The result is
1795 stored in *RESULT_PTR, which must be initialized to NULL.
1796 OUTERMOST_TYPE is the type of the initial type passed to
1797 search_struct_field; this is used for error reporting when the
1798 lookup is ambiguous. */
1799
1800 static void
1801 do_search_struct_field (const char *name, struct value *arg1, LONGEST offset,
1802 struct type *type, int looking_for_baseclass,
1803 struct value **result_ptr,
1804 LONGEST *last_boffset,
1805 struct type *outermost_type)
1806 {
1807 int i;
1808 int nbases;
1809
1810 type = check_typedef (type);
1811 nbases = TYPE_N_BASECLASSES (type);
1812
1813 if (!looking_for_baseclass)
1814 for (i = type->num_fields () - 1; i >= nbases; i--)
1815 {
1816 const char *t_field_name = TYPE_FIELD_NAME (type, i);
1817
1818 if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
1819 {
1820 struct value *v;
1821
1822 if (field_is_static (&type->field (i)))
1823 v = value_static_field (type, i);
1824 else
1825 v = value_primitive_field (arg1, offset, i, type);
1826 *result_ptr = v;
1827 return;
1828 }
1829
1830 if (t_field_name
1831 && t_field_name[0] == '\0')
1832 {
1833 struct type *field_type = type->field (i).type ();
1834
1835 if (field_type->code () == TYPE_CODE_UNION
1836 || field_type->code () == TYPE_CODE_STRUCT)
1837 {
1838 /* Look for a match through the fields of an anonymous
1839 union, or anonymous struct. C++ provides anonymous
1840 unions.
1841
1842 In the GNU Chill (now deleted from GDB)
1843 implementation of variant record types, each
1844 <alternative field> has an (anonymous) union type,
1845 each member of the union represents a <variant
1846 alternative>. Each <variant alternative> is
1847 represented as a struct, with a member for each
1848 <variant field>. */
1849
1850 struct value *v = NULL;
1851 LONGEST new_offset = offset;
1852
1853 /* This is pretty gross. In G++, the offset in an
1854 anonymous union is relative to the beginning of the
1855 enclosing struct. In the GNU Chill (now deleted
1856 from GDB) implementation of variant records, the
1857 bitpos is zero in an anonymous union field, so we
1858 have to add the offset of the union here. */
1859 if (field_type->code () == TYPE_CODE_STRUCT
1860 || (field_type->num_fields () > 0
1861 && TYPE_FIELD_BITPOS (field_type, 0) == 0))
1862 new_offset += TYPE_FIELD_BITPOS (type, i) / 8;
1863
1864 do_search_struct_field (name, arg1, new_offset,
1865 field_type,
1866 looking_for_baseclass, &v,
1867 last_boffset,
1868 outermost_type);
1869 if (v)
1870 {
1871 *result_ptr = v;
1872 return;
1873 }
1874 }
1875 }
1876 }
1877
1878 for (i = 0; i < nbases; i++)
1879 {
1880 struct value *v = NULL;
1881 struct type *basetype = check_typedef (TYPE_BASECLASS (type, i));
1882 /* If we are looking for baseclasses, this is what we get when
1883 we hit them. But it could happen that the base part's member
1884 name is not yet filled in. */
1885 int found_baseclass = (looking_for_baseclass
1886 && TYPE_BASECLASS_NAME (type, i) != NULL
1887 && (strcmp_iw (name,
1888 TYPE_BASECLASS_NAME (type,
1889 i)) == 0));
1890 LONGEST boffset = value_embedded_offset (arg1) + offset;
1891
1892 if (BASETYPE_VIA_VIRTUAL (type, i))
1893 {
1894 struct value *v2;
1895
1896 boffset = baseclass_offset (type, i,
1897 value_contents_for_printing (arg1),
1898 value_embedded_offset (arg1) + offset,
1899 value_address (arg1),
1900 arg1);
1901
1902 /* The virtual base class pointer might have been clobbered
1903 by the user program. Make sure that it still points to a
1904 valid memory location. */
1905
1906 boffset += value_embedded_offset (arg1) + offset;
1907 if (boffset < 0
1908 || boffset >= TYPE_LENGTH (value_enclosing_type (arg1)))
1909 {
1910 CORE_ADDR base_addr;
1911
1912 base_addr = value_address (arg1) + boffset;
1913 v2 = value_at_lazy (basetype, base_addr);
1914 if (target_read_memory (base_addr,
1915 value_contents_raw (v2),
1916 TYPE_LENGTH (value_type (v2))) != 0)
1917 error (_("virtual baseclass botch"));
1918 }
1919 else
1920 {
1921 v2 = value_copy (arg1);
1922 deprecated_set_value_type (v2, basetype);
1923 set_value_embedded_offset (v2, boffset);
1924 }
1925
1926 if (found_baseclass)
1927 v = v2;
1928 else
1929 {
1930 do_search_struct_field (name, v2, 0,
1931 TYPE_BASECLASS (type, i),
1932 looking_for_baseclass,
1933 result_ptr, last_boffset,
1934 outermost_type);
1935 }
1936 }
1937 else if (found_baseclass)
1938 v = value_primitive_field (arg1, offset, i, type);
1939 else
1940 {
1941 do_search_struct_field (name, arg1,
1942 offset + TYPE_BASECLASS_BITPOS (type,
1943 i) / 8,
1944 basetype, looking_for_baseclass,
1945 result_ptr, last_boffset,
1946 outermost_type);
1947 }
1948
1949 update_search_result (result_ptr, v, last_boffset,
1950 boffset, name, outermost_type);
1951 }
1952 }
1953
1954 /* Helper function used by value_struct_elt to recurse through
1955 baseclasses. Look for a field NAME in ARG1. Search in it assuming
1956 it has (class) type TYPE. If found, return value, else return NULL.
1957
1958 If LOOKING_FOR_BASECLASS, then instead of looking for struct
1959 fields, look for a baseclass named NAME. */
1960
1961 static struct value *
1962 search_struct_field (const char *name, struct value *arg1,
1963 struct type *type, int looking_for_baseclass)
1964 {
1965 struct value *result = NULL;
1966 LONGEST boffset = 0;
1967
1968 do_search_struct_field (name, arg1, 0, type, looking_for_baseclass,
1969 &result, &boffset, type);
1970 return result;
1971 }
1972
1973 /* Helper function used by value_struct_elt to recurse through
1974 baseclasses. Look for a field NAME in ARG1. Adjust the address of
1975 ARG1 by OFFSET bytes, and search in it assuming it has (class) type
1976 TYPE.
1977
1978 If found, return value, else if name matched and args not return
1979 (value) -1, else return NULL. */
1980
1981 static struct value *
1982 search_struct_method (const char *name, struct value **arg1p,
1983 struct value **args, LONGEST offset,
1984 int *static_memfuncp, struct type *type)
1985 {
1986 int i;
1987 struct value *v;
1988 int name_matched = 0;
1989
1990 type = check_typedef (type);
1991 for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
1992 {
1993 const char *t_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
1994
1995 if (t_field_name && (strcmp_iw (t_field_name, name) == 0))
1996 {
1997 int j = TYPE_FN_FIELDLIST_LENGTH (type, i) - 1;
1998 struct fn_field *f = TYPE_FN_FIELDLIST1 (type, i);
1999
2000 name_matched = 1;
2001 check_stub_method_group (type, i);
2002 if (j > 0 && args == 0)
2003 error (_("cannot resolve overloaded method "
2004 "`%s': no arguments supplied"), name);
2005 else if (j == 0 && args == 0)
2006 {
2007 v = value_fn_field (arg1p, f, j, type, offset);
2008 if (v != NULL)
2009 return v;
2010 }
2011 else
2012 while (j >= 0)
2013 {
2014 if (!typecmp (TYPE_FN_FIELD_STATIC_P (f, j),
2015 TYPE_VARARGS (TYPE_FN_FIELD_TYPE (f, j)),
2016 TYPE_FN_FIELD_TYPE (f, j)->num_fields (),
2017 TYPE_FN_FIELD_ARGS (f, j), args))
2018 {
2019 if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
2020 return value_virtual_fn_field (arg1p, f, j,
2021 type, offset);
2022 if (TYPE_FN_FIELD_STATIC_P (f, j)
2023 && static_memfuncp)
2024 *static_memfuncp = 1;
2025 v = value_fn_field (arg1p, f, j, type, offset);
2026 if (v != NULL)
2027 return v;
2028 }
2029 j--;
2030 }
2031 }
2032 }
2033
2034 for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
2035 {
2036 LONGEST base_offset;
2037 LONGEST this_offset;
2038
2039 if (BASETYPE_VIA_VIRTUAL (type, i))
2040 {
2041 struct type *baseclass = check_typedef (TYPE_BASECLASS (type, i));
2042 struct value *base_val;
2043 const gdb_byte *base_valaddr;
2044
2045 /* The virtual base class pointer might have been
2046 clobbered by the user program. Make sure that it
2047 still points to a valid memory location. */
2048
2049 if (offset < 0 || offset >= TYPE_LENGTH (type))
2050 {
2051 CORE_ADDR address;
2052
2053 gdb::byte_vector tmp (TYPE_LENGTH (baseclass));
2054 address = value_address (*arg1p);
2055
2056 if (target_read_memory (address + offset,
2057 tmp.data (), TYPE_LENGTH (baseclass)) != 0)
2058 error (_("virtual baseclass botch"));
2059
2060 base_val = value_from_contents_and_address (baseclass,
2061 tmp.data (),
2062 address + offset);
2063 base_valaddr = value_contents_for_printing (base_val);
2064 this_offset = 0;
2065 }
2066 else
2067 {
2068 base_val = *arg1p;
2069 base_valaddr = value_contents_for_printing (*arg1p);
2070 this_offset = offset;
2071 }
2072
2073 base_offset = baseclass_offset (type, i, base_valaddr,
2074 this_offset, value_address (base_val),
2075 base_val);
2076 }
2077 else
2078 {
2079 base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
2080 }
2081 v = search_struct_method (name, arg1p, args, base_offset + offset,
2082 static_memfuncp, TYPE_BASECLASS (type, i));
2083 if (v == (struct value *) - 1)
2084 {
2085 name_matched = 1;
2086 }
2087 else if (v)
2088 {
2089 /* FIXME-bothner: Why is this commented out? Why is it here? */
2090 /* *arg1p = arg1_tmp; */
2091 return v;
2092 }
2093 }
2094 if (name_matched)
2095 return (struct value *) - 1;
2096 else
2097 return NULL;
2098 }
2099
2100 /* Given *ARGP, a value of type (pointer to a)* structure/union,
2101 extract the component named NAME from the ultimate target
2102 structure/union and return it as a value with its appropriate type.
2103 ERR is used in the error message if *ARGP's type is wrong.
2104
2105 C++: ARGS is a list of argument types to aid in the selection of
2106 an appropriate method. Also, handle derived types.
2107
2108 STATIC_MEMFUNCP, if non-NULL, points to a caller-supplied location
2109 where the truthvalue of whether the function that was resolved was
2110 a static member function or not is stored.
2111
2112 ERR is an error message to be printed in case the field is not
2113 found. */
2114
2115 struct value *
2116 value_struct_elt (struct value **argp, struct value **args,
2117 const char *name, int *static_memfuncp, const char *err)
2118 {
2119 struct type *t;
2120 struct value *v;
2121
2122 *argp = coerce_array (*argp);
2123
2124 t = check_typedef (value_type (*argp));
2125
2126 /* Follow pointers until we get to a non-pointer. */
2127
2128 while (t->code () == TYPE_CODE_PTR || TYPE_IS_REFERENCE (t))
2129 {
2130 *argp = value_ind (*argp);
2131 /* Don't coerce fn pointer to fn and then back again! */
2132 if (check_typedef (value_type (*argp))->code () != TYPE_CODE_FUNC)
2133 *argp = coerce_array (*argp);
2134 t = check_typedef (value_type (*argp));
2135 }
2136
2137 if (t->code () != TYPE_CODE_STRUCT
2138 && t->code () != TYPE_CODE_UNION)
2139 error (_("Attempt to extract a component of a value that is not a %s."),
2140 err);
2141
2142 /* Assume it's not, unless we see that it is. */
2143 if (static_memfuncp)
2144 *static_memfuncp = 0;
2145
2146 if (!args)
2147 {
2148 /* if there are no arguments ...do this... */
2149
2150 /* Try as a field first, because if we succeed, there is less
2151 work to be done. */
2152 v = search_struct_field (name, *argp, t, 0);
2153 if (v)
2154 return v;
2155
2156 /* C++: If it was not found as a data field, then try to
2157 return it as a pointer to a method. */
2158 v = search_struct_method (name, argp, args, 0,
2159 static_memfuncp, t);
2160
2161 if (v == (struct value *) - 1)
2162 error (_("Cannot take address of method %s."), name);
2163 else if (v == 0)
2164 {
2165 if (TYPE_NFN_FIELDS (t))
2166 error (_("There is no member or method named %s."), name);
2167 else
2168 error (_("There is no member named %s."), name);
2169 }
2170 return v;
2171 }
2172
2173 v = search_struct_method (name, argp, args, 0,
2174 static_memfuncp, t);
2175
2176 if (v == (struct value *) - 1)
2177 {
2178 error (_("One of the arguments you tried to pass to %s could not "
2179 "be converted to what the function wants."), name);
2180 }
2181 else if (v == 0)
2182 {
2183 /* See if user tried to invoke data as function. If so, hand it
2184 back. If it's not callable (i.e., a pointer to function),
2185 gdb should give an error. */
2186 v = search_struct_field (name, *argp, t, 0);
2187 /* If we found an ordinary field, then it is not a method call.
2188 So, treat it as if it were a static member function. */
2189 if (v && static_memfuncp)
2190 *static_memfuncp = 1;
2191 }
2192
2193 if (!v)
2194 throw_error (NOT_FOUND_ERROR,
2195 _("Structure has no component named %s."), name);
2196 return v;
2197 }
2198
2199 /* Given *ARGP, a value of type structure or union, or a pointer/reference
2200 to a structure or union, extract and return its component (field) of
2201 type FTYPE at the specified BITPOS.
2202 Throw an exception on error. */
2203
2204 struct value *
2205 value_struct_elt_bitpos (struct value **argp, int bitpos, struct type *ftype,
2206 const char *err)
2207 {
2208 struct type *t;
2209 int i;
2210
2211 *argp = coerce_array (*argp);
2212
2213 t = check_typedef (value_type (*argp));
2214
2215 while (t->code () == TYPE_CODE_PTR || TYPE_IS_REFERENCE (t))
2216 {
2217 *argp = value_ind (*argp);
2218 if (check_typedef (value_type (*argp))->code () != TYPE_CODE_FUNC)
2219 *argp = coerce_array (*argp);
2220 t = check_typedef (value_type (*argp));
2221 }
2222
2223 if (t->code () != TYPE_CODE_STRUCT
2224 && t->code () != TYPE_CODE_UNION)
2225 error (_("Attempt to extract a component of a value that is not a %s."),
2226 err);
2227
2228 for (i = TYPE_N_BASECLASSES (t); i < t->num_fields (); i++)
2229 {
2230 if (!field_is_static (&t->field (i))
2231 && bitpos == TYPE_FIELD_BITPOS (t, i)
2232 && types_equal (ftype, t->field (i).type ()))
2233 return value_primitive_field (*argp, 0, i, t);
2234 }
2235
2236 error (_("No field with matching bitpos and type."));
2237
2238 /* Never hit. */
2239 return NULL;
2240 }
2241
2242 /* Search through the methods of an object (and its bases) to find a
2243 specified method. Return a reference to the fn_field list METHODS of
2244 overloaded instances defined in the source language. If available
2245 and matching, a vector of matching xmethods defined in extension
2246 languages are also returned in XMETHODS.
2247
2248 Helper function for value_find_oload_list.
2249 ARGP is a pointer to a pointer to a value (the object).
2250 METHOD is a string containing the method name.
2251 OFFSET is the offset within the value.
2252 TYPE is the assumed type of the object.
2253 METHODS is a pointer to the matching overloaded instances defined
2254 in the source language. Since this is a recursive function,
2255 *METHODS should be set to NULL when calling this function.
2256 NUM_FNS is the number of overloaded instances. *NUM_FNS should be set to
2257 0 when calling this function.
2258 XMETHODS is the vector of matching xmethod workers. *XMETHODS
2259 should also be set to NULL when calling this function.
2260 BASETYPE is set to the actual type of the subobject where the
2261 method is found.
2262 BOFFSET is the offset of the base subobject where the method is found. */
2263
2264 static void
2265 find_method_list (struct value **argp, const char *method,
2266 LONGEST offset, struct type *type,
2267 gdb::array_view<fn_field> *methods,
2268 std::vector<xmethod_worker_up> *xmethods,
2269 struct type **basetype, LONGEST *boffset)
2270 {
2271 int i;
2272 struct fn_field *f = NULL;
2273
2274 gdb_assert (methods != NULL && xmethods != NULL);
2275 type = check_typedef (type);
2276
2277 /* First check in object itself.
2278 This function is called recursively to search through base classes.
2279 If there is a source method match found at some stage, then we need not
2280 look for source methods in consequent recursive calls. */
2281 if (methods->empty ())
2282 {
2283 for (i = TYPE_NFN_FIELDS (type) - 1; i >= 0; i--)
2284 {
2285 /* pai: FIXME What about operators and type conversions? */
2286 const char *fn_field_name = TYPE_FN_FIELDLIST_NAME (type, i);
2287
2288 if (fn_field_name && (strcmp_iw (fn_field_name, method) == 0))
2289 {
2290 int len = TYPE_FN_FIELDLIST_LENGTH (type, i);
2291 f = TYPE_FN_FIELDLIST1 (type, i);
2292 *methods = gdb::make_array_view (f, len);
2293
2294 *basetype = type;
2295 *boffset = offset;
2296
2297 /* Resolve any stub methods. */
2298 check_stub_method_group (type, i);
2299
2300 break;
2301 }
2302 }
2303 }
2304
2305 /* Unlike source methods, xmethods can be accumulated over successive
2306 recursive calls. In other words, an xmethod named 'm' in a class
2307 will not hide an xmethod named 'm' in its base class(es). We want
2308 it to be this way because xmethods are after all convenience functions
2309 and hence there is no point restricting them with something like method
2310 hiding. Moreover, if hiding is done for xmethods as well, then we will
2311 have to provide a mechanism to un-hide (like the 'using' construct). */
2312 get_matching_xmethod_workers (type, method, xmethods);
2313
2314 /* If source methods are not found in current class, look for them in the
2315 base classes. We also have to go through the base classes to gather
2316 extension methods. */
2317 for (i = TYPE_N_BASECLASSES (type) - 1; i >= 0; i--)
2318 {
2319 LONGEST base_offset;
2320
2321 if (BASETYPE_VIA_VIRTUAL (type, i))
2322 {
2323 base_offset = baseclass_offset (type, i,
2324 value_contents_for_printing (*argp),
2325 value_offset (*argp) + offset,
2326 value_address (*argp), *argp);
2327 }
2328 else /* Non-virtual base, simply use bit position from debug
2329 info. */
2330 {
2331 base_offset = TYPE_BASECLASS_BITPOS (type, i) / 8;
2332 }
2333
2334 find_method_list (argp, method, base_offset + offset,
2335 TYPE_BASECLASS (type, i), methods,
2336 xmethods, basetype, boffset);
2337 }
2338 }
2339
2340 /* Return the list of overloaded methods of a specified name. The methods
2341 could be those GDB finds in the binary, or xmethod. Methods found in
2342 the binary are returned in METHODS, and xmethods are returned in
2343 XMETHODS.
2344
2345 ARGP is a pointer to a pointer to a value (the object).
2346 METHOD is the method name.
2347 OFFSET is the offset within the value contents.
2348 METHODS is the list of matching overloaded instances defined in
2349 the source language.
2350 XMETHODS is the vector of matching xmethod workers defined in
2351 extension languages.
2352 BASETYPE is set to the type of the base subobject that defines the
2353 method.
2354 BOFFSET is the offset of the base subobject which defines the method. */
2355
2356 static void
2357 value_find_oload_method_list (struct value **argp, const char *method,
2358 LONGEST offset,
2359 gdb::array_view<fn_field> *methods,
2360 std::vector<xmethod_worker_up> *xmethods,
2361 struct type **basetype, LONGEST *boffset)
2362 {
2363 struct type *t;
2364
2365 t = check_typedef (value_type (*argp));
2366
2367 /* Code snarfed from value_struct_elt. */
2368 while (t->code () == TYPE_CODE_PTR || TYPE_IS_REFERENCE (t))
2369 {
2370 *argp = value_ind (*argp);
2371 /* Don't coerce fn pointer to fn and then back again! */
2372 if (check_typedef (value_type (*argp))->code () != TYPE_CODE_FUNC)
2373 *argp = coerce_array (*argp);
2374 t = check_typedef (value_type (*argp));
2375 }
2376
2377 if (t->code () != TYPE_CODE_STRUCT
2378 && t->code () != TYPE_CODE_UNION)
2379 error (_("Attempt to extract a component of a "
2380 "value that is not a struct or union"));
2381
2382 gdb_assert (methods != NULL && xmethods != NULL);
2383
2384 /* Clear the lists. */
2385 *methods = {};
2386 xmethods->clear ();
2387
2388 find_method_list (argp, method, 0, t, methods, xmethods,
2389 basetype, boffset);
2390 }
2391
2392 /* Given an array of arguments (ARGS) (which includes an entry for
2393 "this" in the case of C++ methods), the NAME of a function, and
2394 whether it's a method or not (METHOD), find the best function that
2395 matches on the argument types according to the overload resolution
2396 rules.
2397
2398 METHOD can be one of three values:
2399 NON_METHOD for non-member functions.
2400 METHOD: for member functions.
2401 BOTH: used for overload resolution of operators where the
2402 candidates are expected to be either member or non member
2403 functions. In this case the first argument ARGTYPES
2404 (representing 'this') is expected to be a reference to the
2405 target object, and will be dereferenced when attempting the
2406 non-member search.
2407
2408 In the case of class methods, the parameter OBJ is an object value
2409 in which to search for overloaded methods.
2410
2411 In the case of non-method functions, the parameter FSYM is a symbol
2412 corresponding to one of the overloaded functions.
2413
2414 Return value is an integer: 0 -> good match, 10 -> debugger applied
2415 non-standard coercions, 100 -> incompatible.
2416
2417 If a method is being searched for, VALP will hold the value.
2418 If a non-method is being searched for, SYMP will hold the symbol
2419 for it.
2420
2421 If a method is being searched for, and it is a static method,
2422 then STATICP will point to a non-zero value.
2423
2424 If NO_ADL argument dependent lookup is disabled. This is used to prevent
2425 ADL overload candidates when performing overload resolution for a fully
2426 qualified name.
2427
2428 If NOSIDE is EVAL_AVOID_SIDE_EFFECTS, then OBJP's memory cannot be
2429 read while picking the best overload match (it may be all zeroes and thus
2430 not have a vtable pointer), in which case skip virtual function lookup.
2431 This is ok as typically EVAL_AVOID_SIDE_EFFECTS is only used to determine
2432 the result type.
2433
2434 Note: This function does *not* check the value of
2435 overload_resolution. Caller must check it to see whether overload
2436 resolution is permitted. */
2437
2438 int
2439 find_overload_match (gdb::array_view<value *> args,
2440 const char *name, enum oload_search_type method,
2441 struct value **objp, struct symbol *fsym,
2442 struct value **valp, struct symbol **symp,
2443 int *staticp, const int no_adl,
2444 const enum noside noside)
2445 {
2446 struct value *obj = (objp ? *objp : NULL);
2447 struct type *obj_type = obj ? value_type (obj) : NULL;
2448 /* Index of best overloaded function. */
2449 int func_oload_champ = -1;
2450 int method_oload_champ = -1;
2451 int src_method_oload_champ = -1;
2452 int ext_method_oload_champ = -1;
2453
2454 /* The measure for the current best match. */
2455 badness_vector method_badness;
2456 badness_vector func_badness;
2457 badness_vector ext_method_badness;
2458 badness_vector src_method_badness;
2459
2460 struct value *temp = obj;
2461 /* For methods, the list of overloaded methods. */
2462 gdb::array_view<fn_field> methods;
2463 /* For non-methods, the list of overloaded function symbols. */
2464 std::vector<symbol *> functions;
2465 /* For xmethods, the vector of xmethod workers. */
2466 std::vector<xmethod_worker_up> xmethods;
2467 struct type *basetype = NULL;
2468 LONGEST boffset;
2469
2470 const char *obj_type_name = NULL;
2471 const char *func_name = NULL;
2472 gdb::unique_xmalloc_ptr<char> temp_func;
2473 enum oload_classification match_quality;
2474 enum oload_classification method_match_quality = INCOMPATIBLE;
2475 enum oload_classification src_method_match_quality = INCOMPATIBLE;
2476 enum oload_classification ext_method_match_quality = INCOMPATIBLE;
2477 enum oload_classification func_match_quality = INCOMPATIBLE;
2478
2479 /* Get the list of overloaded methods or functions. */
2480 if (method == METHOD || method == BOTH)
2481 {
2482 gdb_assert (obj);
2483
2484 /* OBJ may be a pointer value rather than the object itself. */
2485 obj = coerce_ref (obj);
2486 while (check_typedef (value_type (obj))->code () == TYPE_CODE_PTR)
2487 obj = coerce_ref (value_ind (obj));
2488 obj_type_name = value_type (obj)->name ();
2489
2490 /* First check whether this is a data member, e.g. a pointer to
2491 a function. */
2492 if (check_typedef (value_type (obj))->code () == TYPE_CODE_STRUCT)
2493 {
2494 *valp = search_struct_field (name, obj,
2495 check_typedef (value_type (obj)), 0);
2496 if (*valp)
2497 {
2498 *staticp = 1;
2499 return 0;
2500 }
2501 }
2502
2503 /* Retrieve the list of methods with the name NAME. */
2504 value_find_oload_method_list (&temp, name, 0, &methods,
2505 &xmethods, &basetype, &boffset);
2506 /* If this is a method only search, and no methods were found
2507 the search has failed. */
2508 if (method == METHOD && methods.empty () && xmethods.empty ())
2509 error (_("Couldn't find method %s%s%s"),
2510 obj_type_name,
2511 (obj_type_name && *obj_type_name) ? "::" : "",
2512 name);
2513 /* If we are dealing with stub method types, they should have
2514 been resolved by find_method_list via
2515 value_find_oload_method_list above. */
2516 if (!methods.empty ())
2517 {
2518 gdb_assert (TYPE_SELF_TYPE (methods[0].type) != NULL);
2519
2520 src_method_oload_champ
2521 = find_oload_champ (args,
2522 methods.size (),
2523 methods.data (), NULL, NULL,
2524 &src_method_badness);
2525
2526 src_method_match_quality = classify_oload_match
2527 (src_method_badness, args.size (),
2528 oload_method_static_p (methods.data (), src_method_oload_champ));
2529 }
2530
2531 if (!xmethods.empty ())
2532 {
2533 ext_method_oload_champ
2534 = find_oload_champ (args,
2535 xmethods.size (),
2536 NULL, xmethods.data (), NULL,
2537 &ext_method_badness);
2538 ext_method_match_quality = classify_oload_match (ext_method_badness,
2539 args.size (), 0);
2540 }
2541
2542 if (src_method_oload_champ >= 0 && ext_method_oload_champ >= 0)
2543 {
2544 switch (compare_badness (ext_method_badness, src_method_badness))
2545 {
2546 case 0: /* Src method and xmethod are equally good. */
2547 /* If src method and xmethod are equally good, then
2548 xmethod should be the winner. Hence, fall through to the
2549 case where a xmethod is better than the source
2550 method, except when the xmethod match quality is
2551 non-standard. */
2552 /* FALLTHROUGH */
2553 case 1: /* Src method and ext method are incompatible. */
2554 /* If ext method match is not standard, then let source method
2555 win. Otherwise, fallthrough to let xmethod win. */
2556 if (ext_method_match_quality != STANDARD)
2557 {
2558 method_oload_champ = src_method_oload_champ;
2559 method_badness = src_method_badness;
2560 ext_method_oload_champ = -1;
2561 method_match_quality = src_method_match_quality;
2562 break;
2563 }
2564 /* FALLTHROUGH */
2565 case 2: /* Ext method is champion. */
2566 method_oload_champ = ext_method_oload_champ;
2567 method_badness = ext_method_badness;
2568 src_method_oload_champ = -1;
2569 method_match_quality = ext_method_match_quality;
2570 break;
2571 case 3: /* Src method is champion. */
2572 method_oload_champ = src_method_oload_champ;
2573 method_badness = src_method_badness;
2574 ext_method_oload_champ = -1;
2575 method_match_quality = src_method_match_quality;
2576 break;
2577 default:
2578 gdb_assert_not_reached ("Unexpected overload comparison "
2579 "result");
2580 break;
2581 }
2582 }
2583 else if (src_method_oload_champ >= 0)
2584 {
2585 method_oload_champ = src_method_oload_champ;
2586 method_badness = src_method_badness;
2587 method_match_quality = src_method_match_quality;
2588 }
2589 else if (ext_method_oload_champ >= 0)
2590 {
2591 method_oload_champ = ext_method_oload_champ;
2592 method_badness = ext_method_badness;
2593 method_match_quality = ext_method_match_quality;
2594 }
2595 }
2596
2597 if (method == NON_METHOD || method == BOTH)
2598 {
2599 const char *qualified_name = NULL;
2600
2601 /* If the overload match is being search for both as a method
2602 and non member function, the first argument must now be
2603 dereferenced. */
2604 if (method == BOTH)
2605 args[0] = value_ind (args[0]);
2606
2607 if (fsym)
2608 {
2609 qualified_name = fsym->natural_name ();
2610
2611 /* If we have a function with a C++ name, try to extract just
2612 the function part. Do not try this for non-functions (e.g.
2613 function pointers). */
2614 if (qualified_name
2615 && (check_typedef (SYMBOL_TYPE (fsym))->code ()
2616 == TYPE_CODE_FUNC))
2617 {
2618 temp_func = cp_func_name (qualified_name);
2619
2620 /* If cp_func_name did not remove anything, the name of the
2621 symbol did not include scope or argument types - it was
2622 probably a C-style function. */
2623 if (temp_func != nullptr)
2624 {
2625 if (strcmp (temp_func.get (), qualified_name) == 0)
2626 func_name = NULL;
2627 else
2628 func_name = temp_func.get ();
2629 }
2630 }
2631 }
2632 else
2633 {
2634 func_name = name;
2635 qualified_name = name;
2636 }
2637
2638 /* If there was no C++ name, this must be a C-style function or
2639 not a function at all. Just return the same symbol. Do the
2640 same if cp_func_name fails for some reason. */
2641 if (func_name == NULL)
2642 {
2643 *symp = fsym;
2644 return 0;
2645 }
2646
2647 func_oload_champ = find_oload_champ_namespace (args,
2648 func_name,
2649 qualified_name,
2650 &functions,
2651 &func_badness,
2652 no_adl);
2653
2654 if (func_oload_champ >= 0)
2655 func_match_quality = classify_oload_match (func_badness,
2656 args.size (), 0);
2657 }
2658
2659 /* Did we find a match ? */
2660 if (method_oload_champ == -1 && func_oload_champ == -1)
2661 throw_error (NOT_FOUND_ERROR,
2662 _("No symbol \"%s\" in current context."),
2663 name);
2664
2665 /* If we have found both a method match and a function
2666 match, find out which one is better, and calculate match
2667 quality. */
2668 if (method_oload_champ >= 0 && func_oload_champ >= 0)
2669 {
2670 switch (compare_badness (func_badness, method_badness))
2671 {
2672 case 0: /* Top two contenders are equally good. */
2673 /* FIXME: GDB does not support the general ambiguous case.
2674 All candidates should be collected and presented the
2675 user. */
2676 error (_("Ambiguous overload resolution"));
2677 break;
2678 case 1: /* Incomparable top contenders. */
2679 /* This is an error incompatible candidates
2680 should not have been proposed. */
2681 error (_("Internal error: incompatible "
2682 "overload candidates proposed"));
2683 break;
2684 case 2: /* Function champion. */
2685 method_oload_champ = -1;
2686 match_quality = func_match_quality;
2687 break;
2688 case 3: /* Method champion. */
2689 func_oload_champ = -1;
2690 match_quality = method_match_quality;
2691 break;
2692 default:
2693 error (_("Internal error: unexpected overload comparison result"));
2694 break;
2695 }
2696 }
2697 else
2698 {
2699 /* We have either a method match or a function match. */
2700 if (method_oload_champ >= 0)
2701 match_quality = method_match_quality;
2702 else
2703 match_quality = func_match_quality;
2704 }
2705
2706 if (match_quality == INCOMPATIBLE)
2707 {
2708 if (method == METHOD)
2709 error (_("Cannot resolve method %s%s%s to any overloaded instance"),
2710 obj_type_name,
2711 (obj_type_name && *obj_type_name) ? "::" : "",
2712 name);
2713 else
2714 error (_("Cannot resolve function %s to any overloaded instance"),
2715 func_name);
2716 }
2717 else if (match_quality == NON_STANDARD)
2718 {
2719 if (method == METHOD)
2720 warning (_("Using non-standard conversion to match "
2721 "method %s%s%s to supplied arguments"),
2722 obj_type_name,
2723 (obj_type_name && *obj_type_name) ? "::" : "",
2724 name);
2725 else
2726 warning (_("Using non-standard conversion to match "
2727 "function %s to supplied arguments"),
2728 func_name);
2729 }
2730
2731 if (staticp != NULL)
2732 *staticp = oload_method_static_p (methods.data (), method_oload_champ);
2733
2734 if (method_oload_champ >= 0)
2735 {
2736 if (src_method_oload_champ >= 0)
2737 {
2738 if (TYPE_FN_FIELD_VIRTUAL_P (methods, method_oload_champ)
2739 && noside != EVAL_AVOID_SIDE_EFFECTS)
2740 {
2741 *valp = value_virtual_fn_field (&temp, methods.data (),
2742 method_oload_champ, basetype,
2743 boffset);
2744 }
2745 else
2746 *valp = value_fn_field (&temp, methods.data (),
2747 method_oload_champ, basetype, boffset);
2748 }
2749 else
2750 *valp = value_from_xmethod
2751 (std::move (xmethods[ext_method_oload_champ]));
2752 }
2753 else
2754 *symp = functions[func_oload_champ];
2755
2756 if (objp)
2757 {
2758 struct type *temp_type = check_typedef (value_type (temp));
2759 struct type *objtype = check_typedef (obj_type);
2760
2761 if (temp_type->code () != TYPE_CODE_PTR
2762 && (objtype->code () == TYPE_CODE_PTR
2763 || TYPE_IS_REFERENCE (objtype)))
2764 {
2765 temp = value_addr (temp);
2766 }
2767 *objp = temp;
2768 }
2769
2770 switch (match_quality)
2771 {
2772 case INCOMPATIBLE:
2773 return 100;
2774 case NON_STANDARD:
2775 return 10;
2776 default: /* STANDARD */
2777 return 0;
2778 }
2779 }
2780
2781 /* Find the best overload match, searching for FUNC_NAME in namespaces
2782 contained in QUALIFIED_NAME until it either finds a good match or
2783 runs out of namespaces. It stores the overloaded functions in
2784 *OLOAD_SYMS, and the badness vector in *OLOAD_CHAMP_BV. If NO_ADL,
2785 argument dependent lookup is not performed. */
2786
2787 static int
2788 find_oload_champ_namespace (gdb::array_view<value *> args,
2789 const char *func_name,
2790 const char *qualified_name,
2791 std::vector<symbol *> *oload_syms,
2792 badness_vector *oload_champ_bv,
2793 const int no_adl)
2794 {
2795 int oload_champ;
2796
2797 find_oload_champ_namespace_loop (args,
2798 func_name,
2799 qualified_name, 0,
2800 oload_syms, oload_champ_bv,
2801 &oload_champ,
2802 no_adl);
2803
2804 return oload_champ;
2805 }
2806
2807 /* Helper function for find_oload_champ_namespace; NAMESPACE_LEN is
2808 how deep we've looked for namespaces, and the champ is stored in
2809 OLOAD_CHAMP. The return value is 1 if the champ is a good one, 0
2810 if it isn't. Other arguments are the same as in
2811 find_oload_champ_namespace. */
2812
2813 static int
2814 find_oload_champ_namespace_loop (gdb::array_view<value *> args,
2815 const char *func_name,
2816 const char *qualified_name,
2817 int namespace_len,
2818 std::vector<symbol *> *oload_syms,
2819 badness_vector *oload_champ_bv,
2820 int *oload_champ,
2821 const int no_adl)
2822 {
2823 int next_namespace_len = namespace_len;
2824 int searched_deeper = 0;
2825 int new_oload_champ;
2826 char *new_namespace;
2827
2828 if (next_namespace_len != 0)
2829 {
2830 gdb_assert (qualified_name[next_namespace_len] == ':');
2831 next_namespace_len += 2;
2832 }
2833 next_namespace_len +=
2834 cp_find_first_component (qualified_name + next_namespace_len);
2835
2836 /* First, see if we have a deeper namespace we can search in.
2837 If we get a good match there, use it. */
2838
2839 if (qualified_name[next_namespace_len] == ':')
2840 {
2841 searched_deeper = 1;
2842
2843 if (find_oload_champ_namespace_loop (args,
2844 func_name, qualified_name,
2845 next_namespace_len,
2846 oload_syms, oload_champ_bv,
2847 oload_champ, no_adl))
2848 {
2849 return 1;
2850 }
2851 };
2852
2853 /* If we reach here, either we're in the deepest namespace or we
2854 didn't find a good match in a deeper namespace. But, in the
2855 latter case, we still have a bad match in a deeper namespace;
2856 note that we might not find any match at all in the current
2857 namespace. (There's always a match in the deepest namespace,
2858 because this overload mechanism only gets called if there's a
2859 function symbol to start off with.) */
2860
2861 new_namespace = (char *) alloca (namespace_len + 1);
2862 strncpy (new_namespace, qualified_name, namespace_len);
2863 new_namespace[namespace_len] = '\0';
2864
2865 std::vector<symbol *> new_oload_syms
2866 = make_symbol_overload_list (func_name, new_namespace);
2867
2868 /* If we have reached the deepest level perform argument
2869 determined lookup. */
2870 if (!searched_deeper && !no_adl)
2871 {
2872 int ix;
2873 struct type **arg_types;
2874
2875 /* Prepare list of argument types for overload resolution. */
2876 arg_types = (struct type **)
2877 alloca (args.size () * (sizeof (struct type *)));
2878 for (ix = 0; ix < args.size (); ix++)
2879 arg_types[ix] = value_type (args[ix]);
2880 add_symbol_overload_list_adl ({arg_types, args.size ()}, func_name,
2881 &new_oload_syms);
2882 }
2883
2884 badness_vector new_oload_champ_bv;
2885 new_oload_champ = find_oload_champ (args,
2886 new_oload_syms.size (),
2887 NULL, NULL, new_oload_syms.data (),
2888 &new_oload_champ_bv);
2889
2890 /* Case 1: We found a good match. Free earlier matches (if any),
2891 and return it. Case 2: We didn't find a good match, but we're
2892 not the deepest function. Then go with the bad match that the
2893 deeper function found. Case 3: We found a bad match, and we're
2894 the deepest function. Then return what we found, even though
2895 it's a bad match. */
2896
2897 if (new_oload_champ != -1
2898 && classify_oload_match (new_oload_champ_bv, args.size (), 0) == STANDARD)
2899 {
2900 *oload_syms = std::move (new_oload_syms);
2901 *oload_champ = new_oload_champ;
2902 *oload_champ_bv = std::move (new_oload_champ_bv);
2903 return 1;
2904 }
2905 else if (searched_deeper)
2906 {
2907 return 0;
2908 }
2909 else
2910 {
2911 *oload_syms = std::move (new_oload_syms);
2912 *oload_champ = new_oload_champ;
2913 *oload_champ_bv = std::move (new_oload_champ_bv);
2914 return 0;
2915 }
2916 }
2917
2918 /* Look for a function to take ARGS. Find the best match from among
2919 the overloaded methods or functions given by METHODS or FUNCTIONS
2920 or XMETHODS, respectively. One, and only one of METHODS, FUNCTIONS
2921 and XMETHODS can be non-NULL.
2922
2923 NUM_FNS is the length of the array pointed at by METHODS, FUNCTIONS
2924 or XMETHODS, whichever is non-NULL.
2925
2926 Return the index of the best match; store an indication of the
2927 quality of the match in OLOAD_CHAMP_BV. */
2928
2929 static int
2930 find_oload_champ (gdb::array_view<value *> args,
2931 size_t num_fns,
2932 fn_field *methods,
2933 xmethod_worker_up *xmethods,
2934 symbol **functions,
2935 badness_vector *oload_champ_bv)
2936 {
2937 /* A measure of how good an overloaded instance is. */
2938 badness_vector bv;
2939 /* Index of best overloaded function. */
2940 int oload_champ = -1;
2941 /* Current ambiguity state for overload resolution. */
2942 int oload_ambiguous = 0;
2943 /* 0 => no ambiguity, 1 => two good funcs, 2 => incomparable funcs. */
2944
2945 /* A champion can be found among methods alone, or among functions
2946 alone, or in xmethods alone, but not in more than one of these
2947 groups. */
2948 gdb_assert ((methods != NULL) + (functions != NULL) + (xmethods != NULL)
2949 == 1);
2950
2951 /* Consider each candidate in turn. */
2952 for (size_t ix = 0; ix < num_fns; ix++)
2953 {
2954 int jj;
2955 int static_offset = 0;
2956 std::vector<type *> parm_types;
2957
2958 if (xmethods != NULL)
2959 parm_types = xmethods[ix]->get_arg_types ();
2960 else
2961 {
2962 size_t nparms;
2963
2964 if (methods != NULL)
2965 {
2966 nparms = TYPE_FN_FIELD_TYPE (methods, ix)->num_fields ();
2967 static_offset = oload_method_static_p (methods, ix);
2968 }
2969 else
2970 nparms = SYMBOL_TYPE (functions[ix])->num_fields ();
2971
2972 parm_types.reserve (nparms);
2973 for (jj = 0; jj < nparms; jj++)
2974 {
2975 type *t = (methods != NULL
2976 ? (TYPE_FN_FIELD_ARGS (methods, ix)[jj].type ())
2977 : SYMBOL_TYPE (functions[ix])->field (jj).type ());
2978 parm_types.push_back (t);
2979 }
2980 }
2981
2982 /* Compare parameter types to supplied argument types. Skip
2983 THIS for static methods. */
2984 bv = rank_function (parm_types,
2985 args.slice (static_offset));
2986
2987 if (overload_debug)
2988 {
2989 if (methods != NULL)
2990 fprintf_filtered (gdb_stderr,
2991 "Overloaded method instance %s, # of parms %d\n",
2992 methods[ix].physname, (int) parm_types.size ());
2993 else if (xmethods != NULL)
2994 fprintf_filtered (gdb_stderr,
2995 "Xmethod worker, # of parms %d\n",
2996 (int) parm_types.size ());
2997 else
2998 fprintf_filtered (gdb_stderr,
2999 "Overloaded function instance "
3000 "%s # of parms %d\n",
3001 functions[ix]->demangled_name (),
3002 (int) parm_types.size ());
3003
3004 fprintf_filtered (gdb_stderr,
3005 "...Badness of length : {%d, %d}\n",
3006 bv[0].rank, bv[0].subrank);
3007
3008 for (jj = 1; jj < bv.size (); jj++)
3009 fprintf_filtered (gdb_stderr,
3010 "...Badness of arg %d : {%d, %d}\n",
3011 jj, bv[jj].rank, bv[jj].subrank);
3012 }
3013
3014 if (oload_champ_bv->empty ())
3015 {
3016 *oload_champ_bv = std::move (bv);
3017 oload_champ = 0;
3018 }
3019 else /* See whether current candidate is better or worse than
3020 previous best. */
3021 switch (compare_badness (bv, *oload_champ_bv))
3022 {
3023 case 0: /* Top two contenders are equally good. */
3024 oload_ambiguous = 1;
3025 break;
3026 case 1: /* Incomparable top contenders. */
3027 oload_ambiguous = 2;
3028 break;
3029 case 2: /* New champion, record details. */
3030 *oload_champ_bv = std::move (bv);
3031 oload_ambiguous = 0;
3032 oload_champ = ix;
3033 break;
3034 case 3:
3035 default:
3036 break;
3037 }
3038 if (overload_debug)
3039 fprintf_filtered (gdb_stderr, "Overload resolution "
3040 "champion is %d, ambiguous? %d\n",
3041 oload_champ, oload_ambiguous);
3042 }
3043
3044 return oload_champ;
3045 }
3046
3047 /* Return 1 if we're looking at a static method, 0 if we're looking at
3048 a non-static method or a function that isn't a method. */
3049
3050 static int
3051 oload_method_static_p (struct fn_field *fns_ptr, int index)
3052 {
3053 if (fns_ptr && index >= 0 && TYPE_FN_FIELD_STATIC_P (fns_ptr, index))
3054 return 1;
3055 else
3056 return 0;
3057 }
3058
3059 /* Check how good an overload match OLOAD_CHAMP_BV represents. */
3060
3061 static enum oload_classification
3062 classify_oload_match (const badness_vector &oload_champ_bv,
3063 int nargs,
3064 int static_offset)
3065 {
3066 int ix;
3067 enum oload_classification worst = STANDARD;
3068
3069 for (ix = 1; ix <= nargs - static_offset; ix++)
3070 {
3071 /* If this conversion is as bad as INCOMPATIBLE_TYPE_BADNESS
3072 or worse return INCOMPATIBLE. */
3073 if (compare_ranks (oload_champ_bv[ix],
3074 INCOMPATIBLE_TYPE_BADNESS) <= 0)
3075 return INCOMPATIBLE; /* Truly mismatched types. */
3076 /* Otherwise If this conversion is as bad as
3077 NS_POINTER_CONVERSION_BADNESS or worse return NON_STANDARD. */
3078 else if (compare_ranks (oload_champ_bv[ix],
3079 NS_POINTER_CONVERSION_BADNESS) <= 0)
3080 worst = NON_STANDARD; /* Non-standard type conversions
3081 needed. */
3082 }
3083
3084 /* If no INCOMPATIBLE classification was found, return the worst one
3085 that was found (if any). */
3086 return worst;
3087 }
3088
3089 /* C++: return 1 is NAME is a legitimate name for the destructor of
3090 type TYPE. If TYPE does not have a destructor, or if NAME is
3091 inappropriate for TYPE, an error is signaled. Parameter TYPE should not yet
3092 have CHECK_TYPEDEF applied, this function will apply it itself. */
3093
3094 int
3095 destructor_name_p (const char *name, struct type *type)
3096 {
3097 if (name[0] == '~')
3098 {
3099 const char *dname = type_name_or_error (type);
3100 const char *cp = strchr (dname, '<');
3101 unsigned int len;
3102
3103 /* Do not compare the template part for template classes. */
3104 if (cp == NULL)
3105 len = strlen (dname);
3106 else
3107 len = cp - dname;
3108 if (strlen (name + 1) != len || strncmp (dname, name + 1, len) != 0)
3109 error (_("name of destructor must equal name of class"));
3110 else
3111 return 1;
3112 }
3113 return 0;
3114 }
3115
3116 /* Find an enum constant named NAME in TYPE. TYPE must be an "enum
3117 class". If the name is found, return a value representing it;
3118 otherwise throw an exception. */
3119
3120 static struct value *
3121 enum_constant_from_type (struct type *type, const char *name)
3122 {
3123 int i;
3124 int name_len = strlen (name);
3125
3126 gdb_assert (type->code () == TYPE_CODE_ENUM
3127 && TYPE_DECLARED_CLASS (type));
3128
3129 for (i = TYPE_N_BASECLASSES (type); i < type->num_fields (); ++i)
3130 {
3131 const char *fname = TYPE_FIELD_NAME (type, i);
3132 int len;
3133
3134 if (TYPE_FIELD_LOC_KIND (type, i) != FIELD_LOC_KIND_ENUMVAL
3135 || fname == NULL)
3136 continue;
3137
3138 /* Look for the trailing "::NAME", since enum class constant
3139 names are qualified here. */
3140 len = strlen (fname);
3141 if (len + 2 >= name_len
3142 && fname[len - name_len - 2] == ':'
3143 && fname[len - name_len - 1] == ':'
3144 && strcmp (&fname[len - name_len], name) == 0)
3145 return value_from_longest (type, TYPE_FIELD_ENUMVAL (type, i));
3146 }
3147
3148 error (_("no constant named \"%s\" in enum \"%s\""),
3149 name, type->name ());
3150 }
3151
3152 /* C++: Given an aggregate type CURTYPE, and a member name NAME,
3153 return the appropriate member (or the address of the member, if
3154 WANT_ADDRESS). This function is used to resolve user expressions
3155 of the form "DOMAIN::NAME". For more details on what happens, see
3156 the comment before value_struct_elt_for_reference. */
3157
3158 struct value *
3159 value_aggregate_elt (struct type *curtype, const char *name,
3160 struct type *expect_type, int want_address,
3161 enum noside noside)
3162 {
3163 switch (curtype->code ())
3164 {
3165 case TYPE_CODE_STRUCT:
3166 case TYPE_CODE_UNION:
3167 return value_struct_elt_for_reference (curtype, 0, curtype,
3168 name, expect_type,
3169 want_address, noside);
3170 case TYPE_CODE_NAMESPACE:
3171 return value_namespace_elt (curtype, name,
3172 want_address, noside);
3173
3174 case TYPE_CODE_ENUM:
3175 return enum_constant_from_type (curtype, name);
3176
3177 default:
3178 internal_error (__FILE__, __LINE__,
3179 _("non-aggregate type in value_aggregate_elt"));
3180 }
3181 }
3182
3183 /* Compares the two method/function types T1 and T2 for "equality"
3184 with respect to the methods' parameters. If the types of the
3185 two parameter lists are the same, returns 1; 0 otherwise. This
3186 comparison may ignore any artificial parameters in T1 if
3187 SKIP_ARTIFICIAL is non-zero. This function will ALWAYS skip
3188 the first artificial parameter in T1, assumed to be a 'this' pointer.
3189
3190 The type T2 is expected to have come from make_params (in eval.c). */
3191
3192 static int
3193 compare_parameters (struct type *t1, struct type *t2, int skip_artificial)
3194 {
3195 int start = 0;
3196
3197 if (t1->num_fields () > 0 && TYPE_FIELD_ARTIFICIAL (t1, 0))
3198 ++start;
3199
3200 /* If skipping artificial fields, find the first real field
3201 in T1. */
3202 if (skip_artificial)
3203 {
3204 while (start < t1->num_fields ()
3205 && TYPE_FIELD_ARTIFICIAL (t1, start))
3206 ++start;
3207 }
3208
3209 /* Now compare parameters. */
3210
3211 /* Special case: a method taking void. T1 will contain no
3212 non-artificial fields, and T2 will contain TYPE_CODE_VOID. */
3213 if ((t1->num_fields () - start) == 0 && t2->num_fields () == 1
3214 && t2->field (0).type ()->code () == TYPE_CODE_VOID)
3215 return 1;
3216
3217 if ((t1->num_fields () - start) == t2->num_fields ())
3218 {
3219 int i;
3220
3221 for (i = 0; i < t2->num_fields (); ++i)
3222 {
3223 if (compare_ranks (rank_one_type (t1->field (start + i).type (),
3224 t2->field (i).type (), NULL),
3225 EXACT_MATCH_BADNESS) != 0)
3226 return 0;
3227 }
3228
3229 return 1;
3230 }
3231
3232 return 0;
3233 }
3234
3235 /* C++: Given an aggregate type VT, and a class type CLS, search
3236 recursively for CLS using value V; If found, store the offset
3237 which is either fetched from the virtual base pointer if CLS
3238 is virtual or accumulated offset of its parent classes if
3239 CLS is non-virtual in *BOFFS, set ISVIRT to indicate if CLS
3240 is virtual, and return true. If not found, return false. */
3241
3242 static bool
3243 get_baseclass_offset (struct type *vt, struct type *cls,
3244 struct value *v, int *boffs, bool *isvirt)
3245 {
3246 for (int i = 0; i < TYPE_N_BASECLASSES (vt); i++)
3247 {
3248 struct type *t = vt->field (i).type ();
3249 if (types_equal (t, cls))
3250 {
3251 if (BASETYPE_VIA_VIRTUAL (vt, i))
3252 {
3253 const gdb_byte *adr = value_contents_for_printing (v);
3254 *boffs = baseclass_offset (vt, i, adr, value_offset (v),
3255 value_as_long (v), v);
3256 *isvirt = true;
3257 }
3258 else
3259 *isvirt = false;
3260 return true;
3261 }
3262
3263 if (get_baseclass_offset (check_typedef (t), cls, v, boffs, isvirt))
3264 {
3265 if (*isvirt == false) /* Add non-virtual base offset. */
3266 {
3267 const gdb_byte *adr = value_contents_for_printing (v);
3268 *boffs += baseclass_offset (vt, i, adr, value_offset (v),
3269 value_as_long (v), v);
3270 }
3271 return true;
3272 }
3273 }
3274
3275 return false;
3276 }
3277
3278 /* C++: Given an aggregate type CURTYPE, and a member name NAME,
3279 return the address of this member as a "pointer to member" type.
3280 If INTYPE is non-null, then it will be the type of the member we
3281 are looking for. This will help us resolve "pointers to member
3282 functions". This function is used to resolve user expressions of
3283 the form "DOMAIN::NAME". */
3284
3285 static struct value *
3286 value_struct_elt_for_reference (struct type *domain, int offset,
3287 struct type *curtype, const char *name,
3288 struct type *intype,
3289 int want_address,
3290 enum noside noside)
3291 {
3292 struct type *t = check_typedef (curtype);
3293 int i;
3294 struct value *result;
3295
3296 if (t->code () != TYPE_CODE_STRUCT
3297 && t->code () != TYPE_CODE_UNION)
3298 error (_("Internal error: non-aggregate type "
3299 "to value_struct_elt_for_reference"));
3300
3301 for (i = t->num_fields () - 1; i >= TYPE_N_BASECLASSES (t); i--)
3302 {
3303 const char *t_field_name = TYPE_FIELD_NAME (t, i);
3304
3305 if (t_field_name && strcmp (t_field_name, name) == 0)
3306 {
3307 if (field_is_static (&t->field (i)))
3308 {
3309 struct value *v = value_static_field (t, i);
3310 if (want_address)
3311 v = value_addr (v);
3312 return v;
3313 }
3314 if (TYPE_FIELD_PACKED (t, i))
3315 error (_("pointers to bitfield members not allowed"));
3316
3317 if (want_address)
3318 return value_from_longest
3319 (lookup_memberptr_type (t->field (i).type (), domain),
3320 offset + (LONGEST) (TYPE_FIELD_BITPOS (t, i) >> 3));
3321 else if (noside != EVAL_NORMAL)
3322 return allocate_value (t->field (i).type ());
3323 else
3324 {
3325 /* Try to evaluate NAME as a qualified name with implicit
3326 this pointer. In this case, attempt to return the
3327 equivalent to `this->*(&TYPE::NAME)'. */
3328 struct value *v = value_of_this_silent (current_language);
3329 if (v != NULL)
3330 {
3331 struct value *ptr, *this_v = v;
3332 long mem_offset;
3333 struct type *type, *tmp;
3334
3335 ptr = value_aggregate_elt (domain, name, NULL, 1, noside);
3336 type = check_typedef (value_type (ptr));
3337 gdb_assert (type != NULL
3338 && type->code () == TYPE_CODE_MEMBERPTR);
3339 tmp = lookup_pointer_type (TYPE_SELF_TYPE (type));
3340 v = value_cast_pointers (tmp, v, 1);
3341 mem_offset = value_as_long (ptr);
3342 if (domain != curtype)
3343 {
3344 /* Find class offset of type CURTYPE from either its
3345 parent type DOMAIN or the type of implied this. */
3346 int boff = 0;
3347 bool isvirt = false;
3348 if (get_baseclass_offset (domain, curtype, v, &boff,
3349 &isvirt))
3350 mem_offset += boff;
3351 else
3352 {
3353 struct type *p = check_typedef (value_type (this_v));
3354 p = check_typedef (TYPE_TARGET_TYPE (p));
3355 if (get_baseclass_offset (p, curtype, this_v,
3356 &boff, &isvirt))
3357 mem_offset += boff;
3358 }
3359 }
3360 tmp = lookup_pointer_type (TYPE_TARGET_TYPE (type));
3361 result = value_from_pointer (tmp,
3362 value_as_long (v) + mem_offset);
3363 return value_ind (result);
3364 }
3365
3366 error (_("Cannot reference non-static field \"%s\""), name);
3367 }
3368 }
3369 }
3370
3371 /* C++: If it was not found as a data field, then try to return it
3372 as a pointer to a method. */
3373
3374 /* Perform all necessary dereferencing. */
3375 while (intype && intype->code () == TYPE_CODE_PTR)
3376 intype = TYPE_TARGET_TYPE (intype);
3377
3378 for (i = TYPE_NFN_FIELDS (t) - 1; i >= 0; --i)
3379 {
3380 const char *t_field_name = TYPE_FN_FIELDLIST_NAME (t, i);
3381
3382 if (t_field_name && strcmp (t_field_name, name) == 0)
3383 {
3384 int j;
3385 int len = TYPE_FN_FIELDLIST_LENGTH (t, i);
3386 struct fn_field *f = TYPE_FN_FIELDLIST1 (t, i);
3387
3388 check_stub_method_group (t, i);
3389
3390 if (intype)
3391 {
3392 for (j = 0; j < len; ++j)
3393 {
3394 if (TYPE_CONST (intype) != TYPE_FN_FIELD_CONST (f, j))
3395 continue;
3396 if (TYPE_VOLATILE (intype) != TYPE_FN_FIELD_VOLATILE (f, j))
3397 continue;
3398
3399 if (compare_parameters (TYPE_FN_FIELD_TYPE (f, j), intype, 0)
3400 || compare_parameters (TYPE_FN_FIELD_TYPE (f, j),
3401 intype, 1))
3402 break;
3403 }
3404
3405 if (j == len)
3406 error (_("no member function matches "
3407 "that type instantiation"));
3408 }
3409 else
3410 {
3411 int ii;
3412
3413 j = -1;
3414 for (ii = 0; ii < len; ++ii)
3415 {
3416 /* Skip artificial methods. This is necessary if,
3417 for example, the user wants to "print
3418 subclass::subclass" with only one user-defined
3419 constructor. There is no ambiguity in this case.
3420 We are careful here to allow artificial methods
3421 if they are the unique result. */
3422 if (TYPE_FN_FIELD_ARTIFICIAL (f, ii))
3423 {
3424 if (j == -1)
3425 j = ii;
3426 continue;
3427 }
3428
3429 /* Desired method is ambiguous if more than one
3430 method is defined. */
3431 if (j != -1 && !TYPE_FN_FIELD_ARTIFICIAL (f, j))
3432 error (_("non-unique member `%s' requires "
3433 "type instantiation"), name);
3434
3435 j = ii;
3436 }
3437
3438 if (j == -1)
3439 error (_("no matching member function"));
3440 }
3441
3442 if (TYPE_FN_FIELD_STATIC_P (f, j))
3443 {
3444 struct symbol *s =
3445 lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
3446 0, VAR_DOMAIN, 0).symbol;
3447
3448 if (s == NULL)
3449 return NULL;
3450
3451 if (want_address)
3452 return value_addr (read_var_value (s, 0, 0));
3453 else
3454 return read_var_value (s, 0, 0);
3455 }
3456
3457 if (TYPE_FN_FIELD_VIRTUAL_P (f, j))
3458 {
3459 if (want_address)
3460 {
3461 result = allocate_value
3462 (lookup_methodptr_type (TYPE_FN_FIELD_TYPE (f, j)));
3463 cplus_make_method_ptr (value_type (result),
3464 value_contents_writeable (result),
3465 TYPE_FN_FIELD_VOFFSET (f, j), 1);
3466 }
3467 else if (noside == EVAL_AVOID_SIDE_EFFECTS)
3468 return allocate_value (TYPE_FN_FIELD_TYPE (f, j));
3469 else
3470 error (_("Cannot reference virtual member function \"%s\""),
3471 name);
3472 }
3473 else
3474 {
3475 struct symbol *s =
3476 lookup_symbol (TYPE_FN_FIELD_PHYSNAME (f, j),
3477 0, VAR_DOMAIN, 0).symbol;
3478
3479 if (s == NULL)
3480 return NULL;
3481
3482 struct value *v = read_var_value (s, 0, 0);
3483 if (!want_address)
3484 result = v;
3485 else
3486 {
3487 result = allocate_value (lookup_methodptr_type (TYPE_FN_FIELD_TYPE (f, j)));
3488 cplus_make_method_ptr (value_type (result),
3489 value_contents_writeable (result),
3490 value_address (v), 0);
3491 }
3492 }
3493 return result;
3494 }
3495 }
3496 for (i = TYPE_N_BASECLASSES (t) - 1; i >= 0; i--)
3497 {
3498 struct value *v;
3499 int base_offset;
3500
3501 if (BASETYPE_VIA_VIRTUAL (t, i))
3502 base_offset = 0;
3503 else
3504 base_offset = TYPE_BASECLASS_BITPOS (t, i) / 8;
3505 v = value_struct_elt_for_reference (domain,
3506 offset + base_offset,
3507 TYPE_BASECLASS (t, i),
3508 name, intype,
3509 want_address, noside);
3510 if (v)
3511 return v;
3512 }
3513
3514 /* As a last chance, pretend that CURTYPE is a namespace, and look
3515 it up that way; this (frequently) works for types nested inside
3516 classes. */
3517
3518 return value_maybe_namespace_elt (curtype, name,
3519 want_address, noside);
3520 }
3521
3522 /* C++: Return the member NAME of the namespace given by the type
3523 CURTYPE. */
3524
3525 static struct value *
3526 value_namespace_elt (const struct type *curtype,
3527 const char *name, int want_address,
3528 enum noside noside)
3529 {
3530 struct value *retval = value_maybe_namespace_elt (curtype, name,
3531 want_address,
3532 noside);
3533
3534 if (retval == NULL)
3535 error (_("No symbol \"%s\" in namespace \"%s\"."),
3536 name, curtype->name ());
3537
3538 return retval;
3539 }
3540
3541 /* A helper function used by value_namespace_elt and
3542 value_struct_elt_for_reference. It looks up NAME inside the
3543 context CURTYPE; this works if CURTYPE is a namespace or if CURTYPE
3544 is a class and NAME refers to a type in CURTYPE itself (as opposed
3545 to, say, some base class of CURTYPE). */
3546
3547 static struct value *
3548 value_maybe_namespace_elt (const struct type *curtype,
3549 const char *name, int want_address,
3550 enum noside noside)
3551 {
3552 const char *namespace_name = curtype->name ();
3553 struct block_symbol sym;
3554 struct value *result;
3555
3556 sym = cp_lookup_symbol_namespace (namespace_name, name,
3557 get_selected_block (0), VAR_DOMAIN);
3558
3559 if (sym.symbol == NULL)
3560 return NULL;
3561 else if ((noside == EVAL_AVOID_SIDE_EFFECTS)
3562 && (SYMBOL_CLASS (sym.symbol) == LOC_TYPEDEF))
3563 result = allocate_value (SYMBOL_TYPE (sym.symbol));
3564 else
3565 result = value_of_variable (sym.symbol, sym.block);
3566
3567 if (want_address)
3568 result = value_addr (result);
3569
3570 return result;
3571 }
3572
3573 /* Given a pointer or a reference value V, find its real (RTTI) type.
3574
3575 Other parameters FULL, TOP, USING_ENC as with value_rtti_type()
3576 and refer to the values computed for the object pointed to. */
3577
3578 struct type *
3579 value_rtti_indirect_type (struct value *v, int *full,
3580 LONGEST *top, int *using_enc)
3581 {
3582 struct value *target = NULL;
3583 struct type *type, *real_type, *target_type;
3584
3585 type = value_type (v);
3586 type = check_typedef (type);
3587 if (TYPE_IS_REFERENCE (type))
3588 target = coerce_ref (v);
3589 else if (type->code () == TYPE_CODE_PTR)
3590 {
3591
3592 try
3593 {
3594 target = value_ind (v);
3595 }
3596 catch (const gdb_exception_error &except)
3597 {
3598 if (except.error == MEMORY_ERROR)
3599 {
3600 /* value_ind threw a memory error. The pointer is NULL or
3601 contains an uninitialized value: we can't determine any
3602 type. */
3603 return NULL;
3604 }
3605 throw;
3606 }
3607 }
3608 else
3609 return NULL;
3610
3611 real_type = value_rtti_type (target, full, top, using_enc);
3612
3613 if (real_type)
3614 {
3615 /* Copy qualifiers to the referenced object. */
3616 target_type = value_type (target);
3617 real_type = make_cv_type (TYPE_CONST (target_type),
3618 TYPE_VOLATILE (target_type), real_type, NULL);
3619 if (TYPE_IS_REFERENCE (type))
3620 real_type = lookup_reference_type (real_type, type->code ());
3621 else if (type->code () == TYPE_CODE_PTR)
3622 real_type = lookup_pointer_type (real_type);
3623 else
3624 internal_error (__FILE__, __LINE__, _("Unexpected value type."));
3625
3626 /* Copy qualifiers to the pointer/reference. */
3627 real_type = make_cv_type (TYPE_CONST (type), TYPE_VOLATILE (type),
3628 real_type, NULL);
3629 }
3630
3631 return real_type;
3632 }
3633
3634 /* Given a value pointed to by ARGP, check its real run-time type, and
3635 if that is different from the enclosing type, create a new value
3636 using the real run-time type as the enclosing type (and of the same
3637 type as ARGP) and return it, with the embedded offset adjusted to
3638 be the correct offset to the enclosed object. RTYPE is the type,
3639 and XFULL, XTOP, and XUSING_ENC are the other parameters, computed
3640 by value_rtti_type(). If these are available, they can be supplied
3641 and a second call to value_rtti_type() is avoided. (Pass RTYPE ==
3642 NULL if they're not available. */
3643
3644 struct value *
3645 value_full_object (struct value *argp,
3646 struct type *rtype,
3647 int xfull, int xtop,
3648 int xusing_enc)
3649 {
3650 struct type *real_type;
3651 int full = 0;
3652 LONGEST top = -1;
3653 int using_enc = 0;
3654 struct value *new_val;
3655
3656 if (rtype)
3657 {
3658 real_type = rtype;
3659 full = xfull;
3660 top = xtop;
3661 using_enc = xusing_enc;
3662 }
3663 else
3664 real_type = value_rtti_type (argp, &full, &top, &using_enc);
3665
3666 /* If no RTTI data, or if object is already complete, do nothing. */
3667 if (!real_type || real_type == value_enclosing_type (argp))
3668 return argp;
3669
3670 /* In a destructor we might see a real type that is a superclass of
3671 the object's type. In this case it is better to leave the object
3672 as-is. */
3673 if (full
3674 && TYPE_LENGTH (real_type) < TYPE_LENGTH (value_enclosing_type (argp)))
3675 return argp;
3676
3677 /* If we have the full object, but for some reason the enclosing
3678 type is wrong, set it. */
3679 /* pai: FIXME -- sounds iffy */
3680 if (full)
3681 {
3682 argp = value_copy (argp);
3683 set_value_enclosing_type (argp, real_type);
3684 return argp;
3685 }
3686
3687 /* Check if object is in memory. */
3688 if (VALUE_LVAL (argp) != lval_memory)
3689 {
3690 warning (_("Couldn't retrieve complete object of RTTI "
3691 "type %s; object may be in register(s)."),
3692 real_type->name ());
3693
3694 return argp;
3695 }
3696
3697 /* All other cases -- retrieve the complete object. */
3698 /* Go back by the computed top_offset from the beginning of the
3699 object, adjusting for the embedded offset of argp if that's what
3700 value_rtti_type used for its computation. */
3701 new_val = value_at_lazy (real_type, value_address (argp) - top +
3702 (using_enc ? 0 : value_embedded_offset (argp)));
3703 deprecated_set_value_type (new_val, value_type (argp));
3704 set_value_embedded_offset (new_val, (using_enc
3705 ? top + value_embedded_offset (argp)
3706 : top));
3707 return new_val;
3708 }
3709
3710
3711 /* Return the value of the local variable, if one exists. Throw error
3712 otherwise, such as if the request is made in an inappropriate context. */
3713
3714 struct value *
3715 value_of_this (const struct language_defn *lang)
3716 {
3717 struct block_symbol sym;
3718 const struct block *b;
3719 struct frame_info *frame;
3720
3721 if (!lang->la_name_of_this)
3722 error (_("no `this' in current language"));
3723
3724 frame = get_selected_frame (_("no frame selected"));
3725
3726 b = get_frame_block (frame, NULL);
3727
3728 sym = lookup_language_this (lang, b);
3729 if (sym.symbol == NULL)
3730 error (_("current stack frame does not contain a variable named `%s'"),
3731 lang->la_name_of_this);
3732
3733 return read_var_value (sym.symbol, sym.block, frame);
3734 }
3735
3736 /* Return the value of the local variable, if one exists. Return NULL
3737 otherwise. Never throw error. */
3738
3739 struct value *
3740 value_of_this_silent (const struct language_defn *lang)
3741 {
3742 struct value *ret = NULL;
3743
3744 try
3745 {
3746 ret = value_of_this (lang);
3747 }
3748 catch (const gdb_exception_error &except)
3749 {
3750 }
3751
3752 return ret;
3753 }
3754
3755 /* Create a slice (sub-string, sub-array) of ARRAY, that is LENGTH
3756 elements long, starting at LOWBOUND. The result has the same lower
3757 bound as the original ARRAY. */
3758
3759 struct value *
3760 value_slice (struct value *array, int lowbound, int length)
3761 {
3762 struct type *slice_range_type, *slice_type, *range_type;
3763 LONGEST lowerbound, upperbound;
3764 struct value *slice;
3765 struct type *array_type;
3766
3767 array_type = check_typedef (value_type (array));
3768 if (array_type->code () != TYPE_CODE_ARRAY
3769 && array_type->code () != TYPE_CODE_STRING)
3770 error (_("cannot take slice of non-array"));
3771
3772 if (type_not_allocated (array_type))
3773 error (_("array not allocated"));
3774 if (type_not_associated (array_type))
3775 error (_("array not associated"));
3776
3777 range_type = array_type->index_type ();
3778 if (get_discrete_bounds (range_type, &lowerbound, &upperbound) < 0)
3779 error (_("slice from bad array or bitstring"));
3780
3781 if (lowbound < lowerbound || length < 0
3782 || lowbound + length - 1 > upperbound)
3783 error (_("slice out of range"));
3784
3785 /* FIXME-type-allocation: need a way to free this type when we are
3786 done with it. */
3787 slice_range_type = create_static_range_type (NULL,
3788 TYPE_TARGET_TYPE (range_type),
3789 lowbound,
3790 lowbound + length - 1);
3791
3792 {
3793 struct type *element_type = TYPE_TARGET_TYPE (array_type);
3794 LONGEST offset
3795 = (lowbound - lowerbound) * TYPE_LENGTH (check_typedef (element_type));
3796
3797 slice_type = create_array_type (NULL,
3798 element_type,
3799 slice_range_type);
3800 slice_type->set_code (array_type->code ());
3801
3802 if (VALUE_LVAL (array) == lval_memory && value_lazy (array))
3803 slice = allocate_value_lazy (slice_type);
3804 else
3805 {
3806 slice = allocate_value (slice_type);
3807 value_contents_copy (slice, 0, array, offset,
3808 type_length_units (slice_type));
3809 }
3810
3811 set_value_component_location (slice, array);
3812 set_value_offset (slice, value_offset (array) + offset);
3813 }
3814
3815 return slice;
3816 }
3817
3818 /* See value.h. */
3819
3820 struct value *
3821 value_literal_complex (struct value *arg1,
3822 struct value *arg2,
3823 struct type *type)
3824 {
3825 struct value *val;
3826 struct type *real_type = TYPE_TARGET_TYPE (type);
3827
3828 val = allocate_value (type);
3829 arg1 = value_cast (real_type, arg1);
3830 arg2 = value_cast (real_type, arg2);
3831
3832 memcpy (value_contents_raw (val),
3833 value_contents (arg1), TYPE_LENGTH (real_type));
3834 memcpy (value_contents_raw (val) + TYPE_LENGTH (real_type),
3835 value_contents (arg2), TYPE_LENGTH (real_type));
3836 return val;
3837 }
3838
3839 /* See value.h. */
3840
3841 struct value *
3842 value_real_part (struct value *value)
3843 {
3844 struct type *type = check_typedef (value_type (value));
3845 struct type *ttype = TYPE_TARGET_TYPE (type);
3846
3847 gdb_assert (type->code () == TYPE_CODE_COMPLEX);
3848 return value_from_component (value, ttype, 0);
3849 }
3850
3851 /* See value.h. */
3852
3853 struct value *
3854 value_imaginary_part (struct value *value)
3855 {
3856 struct type *type = check_typedef (value_type (value));
3857 struct type *ttype = TYPE_TARGET_TYPE (type);
3858
3859 gdb_assert (type->code () == TYPE_CODE_COMPLEX);
3860 return value_from_component (value, ttype,
3861 TYPE_LENGTH (check_typedef (ttype)));
3862 }
3863
3864 /* Cast a value into the appropriate complex data type. */
3865
3866 static struct value *
3867 cast_into_complex (struct type *type, struct value *val)
3868 {
3869 struct type *real_type = TYPE_TARGET_TYPE (type);
3870
3871 if (value_type (val)->code () == TYPE_CODE_COMPLEX)
3872 {
3873 struct type *val_real_type = TYPE_TARGET_TYPE (value_type (val));
3874 struct value *re_val = allocate_value (val_real_type);
3875 struct value *im_val = allocate_value (val_real_type);
3876
3877 memcpy (value_contents_raw (re_val),
3878 value_contents (val), TYPE_LENGTH (val_real_type));
3879 memcpy (value_contents_raw (im_val),
3880 value_contents (val) + TYPE_LENGTH (val_real_type),
3881 TYPE_LENGTH (val_real_type));
3882
3883 return value_literal_complex (re_val, im_val, type);
3884 }
3885 else if (value_type (val)->code () == TYPE_CODE_FLT
3886 || value_type (val)->code () == TYPE_CODE_INT)
3887 return value_literal_complex (val,
3888 value_zero (real_type, not_lval),
3889 type);
3890 else
3891 error (_("cannot cast non-number to complex"));
3892 }
3893
3894 void _initialize_valops ();
3895 void
3896 _initialize_valops ()
3897 {
3898 add_setshow_boolean_cmd ("overload-resolution", class_support,
3899 &overload_resolution, _("\
3900 Set overload resolution in evaluating C++ functions."), _("\
3901 Show overload resolution in evaluating C++ functions."),
3902 NULL, NULL,
3903 show_overload_resolution,
3904 &setlist, &showlist);
3905 overload_resolution = 1;
3906 }
3907