PR c++/51079, DR 495
[gcc.git] / gcc / cp / call.c
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,
4 2010, 2011
5 Free Software Foundation, Inc.
6 Contributed by Michael Tiemann (tiemann@cygnus.com) and
7 modified by Brendan Kehoe (brendan@cygnus.com).
8
9 This file is part of GCC.
10
11 GCC is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 3, or (at your option)
14 any later version.
15
16 GCC is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
20
21 You should have received a copy of the GNU General Public License
22 along with GCC; see the file COPYING3. If not see
23 <http://www.gnu.org/licenses/>. */
24
25
26 /* High-level class interface. */
27
28 #include "config.h"
29 #include "system.h"
30 #include "coretypes.h"
31 #include "tm.h"
32 #include "tree.h"
33 #include "cp-tree.h"
34 #include "output.h"
35 #include "flags.h"
36 #include "toplev.h"
37 #include "diagnostic-core.h"
38 #include "intl.h"
39 #include "target.h"
40 #include "convert.h"
41 #include "langhooks.h"
42 #include "c-family/c-objc.h"
43 #include "timevar.h"
44
45 /* The various kinds of conversion. */
46
47 typedef enum conversion_kind {
48 ck_identity,
49 ck_lvalue,
50 ck_qual,
51 ck_std,
52 ck_ptr,
53 ck_pmem,
54 ck_base,
55 ck_ref_bind,
56 ck_user,
57 ck_ambig,
58 ck_list,
59 ck_aggr,
60 ck_rvalue
61 } conversion_kind;
62
63 /* The rank of the conversion. Order of the enumerals matters; better
64 conversions should come earlier in the list. */
65
66 typedef enum conversion_rank {
67 cr_identity,
68 cr_exact,
69 cr_promotion,
70 cr_std,
71 cr_pbool,
72 cr_user,
73 cr_ellipsis,
74 cr_bad
75 } conversion_rank;
76
77 /* An implicit conversion sequence, in the sense of [over.best.ics].
78 The first conversion to be performed is at the end of the chain.
79 That conversion is always a cr_identity conversion. */
80
81 typedef struct conversion conversion;
82 struct conversion {
83 /* The kind of conversion represented by this step. */
84 conversion_kind kind;
85 /* The rank of this conversion. */
86 conversion_rank rank;
87 BOOL_BITFIELD user_conv_p : 1;
88 BOOL_BITFIELD ellipsis_p : 1;
89 BOOL_BITFIELD this_p : 1;
90 /* True if this conversion would be permitted with a bending of
91 language standards, e.g. disregarding pointer qualifiers or
92 converting integers to pointers. */
93 BOOL_BITFIELD bad_p : 1;
94 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
95 temporary should be created to hold the result of the
96 conversion. */
97 BOOL_BITFIELD need_temporary_p : 1;
98 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
99 from a pointer-to-derived to pointer-to-base is being performed. */
100 BOOL_BITFIELD base_p : 1;
101 /* If KIND is ck_ref_bind, true when either an lvalue reference is
102 being bound to an lvalue expression or an rvalue reference is
103 being bound to an rvalue expression. If KIND is ck_rvalue,
104 true when we should treat an lvalue as an rvalue (12.8p33). If
105 KIND is ck_base, always false. */
106 BOOL_BITFIELD rvaluedness_matches_p: 1;
107 BOOL_BITFIELD check_narrowing: 1;
108 /* The type of the expression resulting from the conversion. */
109 tree type;
110 union {
111 /* The next conversion in the chain. Since the conversions are
112 arranged from outermost to innermost, the NEXT conversion will
113 actually be performed before this conversion. This variant is
114 used only when KIND is neither ck_identity nor ck_ambig. */
115 conversion *next;
116 /* The expression at the beginning of the conversion chain. This
117 variant is used only if KIND is ck_identity or ck_ambig. */
118 tree expr;
119 /* The array of conversions for an initializer_list. */
120 conversion **list;
121 } u;
122 /* The function candidate corresponding to this conversion
123 sequence. This field is only used if KIND is ck_user. */
124 struct z_candidate *cand;
125 };
126
127 #define CONVERSION_RANK(NODE) \
128 ((NODE)->bad_p ? cr_bad \
129 : (NODE)->ellipsis_p ? cr_ellipsis \
130 : (NODE)->user_conv_p ? cr_user \
131 : (NODE)->rank)
132
133 #define BAD_CONVERSION_RANK(NODE) \
134 ((NODE)->ellipsis_p ? cr_ellipsis \
135 : (NODE)->user_conv_p ? cr_user \
136 : (NODE)->rank)
137
138 static struct obstack conversion_obstack;
139 static bool conversion_obstack_initialized;
140 struct rejection_reason;
141
142 static struct z_candidate * tourney (struct z_candidate *);
143 static int equal_functions (tree, tree);
144 static int joust (struct z_candidate *, struct z_candidate *, bool);
145 static int compare_ics (conversion *, conversion *);
146 static tree build_over_call (struct z_candidate *, int, tsubst_flags_t);
147 static tree build_java_interface_fn_ref (tree, tree);
148 #define convert_like(CONV, EXPR, COMPLAIN) \
149 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
150 /*issue_conversion_warnings=*/true, \
151 /*c_cast_p=*/false, (COMPLAIN))
152 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
153 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
154 /*issue_conversion_warnings=*/true, \
155 /*c_cast_p=*/false, (COMPLAIN))
156 static tree convert_like_real (conversion *, tree, tree, int, int, bool,
157 bool, tsubst_flags_t);
158 static void op_error (enum tree_code, enum tree_code, tree, tree,
159 tree, bool);
160 static struct z_candidate *build_user_type_conversion_1 (tree, tree, int);
161 static void print_z_candidate (const char *, struct z_candidate *);
162 static void print_z_candidates (location_t, struct z_candidate *);
163 static tree build_this (tree);
164 static struct z_candidate *splice_viable (struct z_candidate *, bool, bool *);
165 static bool any_strictly_viable (struct z_candidate *);
166 static struct z_candidate *add_template_candidate
167 (struct z_candidate **, tree, tree, tree, tree, const VEC(tree,gc) *,
168 tree, tree, tree, int, unification_kind_t);
169 static struct z_candidate *add_template_candidate_real
170 (struct z_candidate **, tree, tree, tree, tree, const VEC(tree,gc) *,
171 tree, tree, tree, int, tree, unification_kind_t);
172 static struct z_candidate *add_template_conv_candidate
173 (struct z_candidate **, tree, tree, tree, const VEC(tree,gc) *, tree,
174 tree, tree);
175 static void add_builtin_candidates
176 (struct z_candidate **, enum tree_code, enum tree_code,
177 tree, tree *, int);
178 static void add_builtin_candidate
179 (struct z_candidate **, enum tree_code, enum tree_code,
180 tree, tree, tree, tree *, tree *, int);
181 static bool is_complete (tree);
182 static void build_builtin_candidate
183 (struct z_candidate **, tree, tree, tree, tree *, tree *,
184 int);
185 static struct z_candidate *add_conv_candidate
186 (struct z_candidate **, tree, tree, tree, const VEC(tree,gc) *, tree,
187 tree);
188 static struct z_candidate *add_function_candidate
189 (struct z_candidate **, tree, tree, tree, const VEC(tree,gc) *, tree,
190 tree, int);
191 static conversion *implicit_conversion (tree, tree, tree, bool, int);
192 static conversion *standard_conversion (tree, tree, tree, bool, int);
193 static conversion *reference_binding (tree, tree, tree, bool, int);
194 static conversion *build_conv (conversion_kind, tree, conversion *);
195 static conversion *build_list_conv (tree, tree, int);
196 static bool is_subseq (conversion *, conversion *);
197 static conversion *maybe_handle_ref_bind (conversion **);
198 static void maybe_handle_implicit_object (conversion **);
199 static struct z_candidate *add_candidate
200 (struct z_candidate **, tree, tree, const VEC(tree,gc) *, size_t,
201 conversion **, tree, tree, int, struct rejection_reason *);
202 static tree source_type (conversion *);
203 static void add_warning (struct z_candidate *, struct z_candidate *);
204 static bool reference_compatible_p (tree, tree);
205 static conversion *direct_reference_binding (tree, conversion *);
206 static bool promoted_arithmetic_type_p (tree);
207 static conversion *conditional_conversion (tree, tree);
208 static char *name_as_c_string (tree, tree, bool *);
209 static tree prep_operand (tree);
210 static void add_candidates (tree, tree, const VEC(tree,gc) *, tree, tree, bool,
211 tree, tree, int, struct z_candidate **);
212 static conversion *merge_conversion_sequences (conversion *, conversion *);
213 static bool magic_varargs_p (tree);
214 static tree build_temp (tree, tree, int, diagnostic_t *, tsubst_flags_t);
215
216 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
217 NAME can take many forms... */
218
219 bool
220 check_dtor_name (tree basetype, tree name)
221 {
222 /* Just accept something we've already complained about. */
223 if (name == error_mark_node)
224 return true;
225
226 if (TREE_CODE (name) == TYPE_DECL)
227 name = TREE_TYPE (name);
228 else if (TYPE_P (name))
229 /* OK */;
230 else if (TREE_CODE (name) == IDENTIFIER_NODE)
231 {
232 if ((MAYBE_CLASS_TYPE_P (basetype)
233 && name == constructor_name (basetype))
234 || (TREE_CODE (basetype) == ENUMERAL_TYPE
235 && name == TYPE_IDENTIFIER (basetype)))
236 return true;
237 else
238 name = get_type_value (name);
239 }
240 else
241 {
242 /* In the case of:
243
244 template <class T> struct S { ~S(); };
245 int i;
246 i.~S();
247
248 NAME will be a class template. */
249 gcc_assert (DECL_CLASS_TEMPLATE_P (name));
250 return false;
251 }
252
253 if (!name || name == error_mark_node)
254 return false;
255 return same_type_p (TYPE_MAIN_VARIANT (basetype), TYPE_MAIN_VARIANT (name));
256 }
257
258 /* We want the address of a function or method. We avoid creating a
259 pointer-to-member function. */
260
261 tree
262 build_addr_func (tree function)
263 {
264 tree type = TREE_TYPE (function);
265
266 /* We have to do these by hand to avoid real pointer to member
267 functions. */
268 if (TREE_CODE (type) == METHOD_TYPE)
269 {
270 if (TREE_CODE (function) == OFFSET_REF)
271 {
272 tree object = build_address (TREE_OPERAND (function, 0));
273 return get_member_function_from_ptrfunc (&object,
274 TREE_OPERAND (function, 1));
275 }
276 function = build_address (function);
277 }
278 else
279 function = decay_conversion (function);
280
281 return function;
282 }
283
284 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
285 POINTER_TYPE to those. Note, pointer to member function types
286 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
287 two variants. build_call_a is the primitive taking an array of
288 arguments, while build_call_n is a wrapper that handles varargs. */
289
290 tree
291 build_call_n (tree function, int n, ...)
292 {
293 if (n == 0)
294 return build_call_a (function, 0, NULL);
295 else
296 {
297 tree *argarray = XALLOCAVEC (tree, n);
298 va_list ap;
299 int i;
300
301 va_start (ap, n);
302 for (i = 0; i < n; i++)
303 argarray[i] = va_arg (ap, tree);
304 va_end (ap);
305 return build_call_a (function, n, argarray);
306 }
307 }
308
309 /* Update various flags in cfun and the call itself based on what is being
310 called. Split out of build_call_a so that bot_manip can use it too. */
311
312 void
313 set_flags_from_callee (tree call)
314 {
315 int nothrow;
316 tree decl = get_callee_fndecl (call);
317
318 /* We check both the decl and the type; a function may be known not to
319 throw without being declared throw(). */
320 nothrow = ((decl && TREE_NOTHROW (decl))
321 || TYPE_NOTHROW_P (TREE_TYPE (TREE_TYPE (CALL_EXPR_FN (call)))));
322
323 if (!nothrow && at_function_scope_p () && cfun && cp_function_chain)
324 cp_function_chain->can_throw = 1;
325
326 if (decl && TREE_THIS_VOLATILE (decl) && cfun && cp_function_chain)
327 current_function_returns_abnormally = 1;
328
329 TREE_NOTHROW (call) = nothrow;
330 }
331
332 tree
333 build_call_a (tree function, int n, tree *argarray)
334 {
335 tree decl;
336 tree result_type;
337 tree fntype;
338 int i;
339
340 function = build_addr_func (function);
341
342 gcc_assert (TYPE_PTR_P (TREE_TYPE (function)));
343 fntype = TREE_TYPE (TREE_TYPE (function));
344 gcc_assert (TREE_CODE (fntype) == FUNCTION_TYPE
345 || TREE_CODE (fntype) == METHOD_TYPE);
346 result_type = TREE_TYPE (fntype);
347 /* An rvalue has no cv-qualifiers. */
348 if (SCALAR_TYPE_P (result_type) || VOID_TYPE_P (result_type))
349 result_type = cv_unqualified (result_type);
350
351 function = build_call_array_loc (input_location,
352 result_type, function, n, argarray);
353 set_flags_from_callee (function);
354
355 decl = get_callee_fndecl (function);
356
357 if (decl && !TREE_USED (decl))
358 {
359 /* We invoke build_call directly for several library
360 functions. These may have been declared normally if
361 we're building libgcc, so we can't just check
362 DECL_ARTIFICIAL. */
363 gcc_assert (DECL_ARTIFICIAL (decl)
364 || !strncmp (IDENTIFIER_POINTER (DECL_NAME (decl)),
365 "__", 2));
366 mark_used (decl);
367 }
368
369 if (decl && TREE_DEPRECATED (decl))
370 warn_deprecated_use (decl, NULL_TREE);
371 require_complete_eh_spec_types (fntype, decl);
372
373 TREE_HAS_CONSTRUCTOR (function) = (decl && DECL_CONSTRUCTOR_P (decl));
374
375 /* Don't pass empty class objects by value. This is useful
376 for tags in STL, which are used to control overload resolution.
377 We don't need to handle other cases of copying empty classes. */
378 if (! decl || ! DECL_BUILT_IN (decl))
379 for (i = 0; i < n; i++)
380 {
381 tree arg = CALL_EXPR_ARG (function, i);
382 if (is_empty_class (TREE_TYPE (arg))
383 && ! TREE_ADDRESSABLE (TREE_TYPE (arg)))
384 {
385 tree t = build0 (EMPTY_CLASS_EXPR, TREE_TYPE (arg));
386 arg = build2 (COMPOUND_EXPR, TREE_TYPE (t), arg, t);
387 CALL_EXPR_ARG (function, i) = arg;
388 }
389 }
390
391 return function;
392 }
393
394 /* Build something of the form ptr->method (args)
395 or object.method (args). This can also build
396 calls to constructors, and find friends.
397
398 Member functions always take their class variable
399 as a pointer.
400
401 INSTANCE is a class instance.
402
403 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
404
405 PARMS help to figure out what that NAME really refers to.
406
407 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
408 down to the real instance type to use for access checking. We need this
409 information to get protected accesses correct.
410
411 FLAGS is the logical disjunction of zero or more LOOKUP_
412 flags. See cp-tree.h for more info.
413
414 If this is all OK, calls build_function_call with the resolved
415 member function.
416
417 This function must also handle being called to perform
418 initialization, promotion/coercion of arguments, and
419 instantiation of default parameters.
420
421 Note that NAME may refer to an instance variable name. If
422 `operator()()' is defined for the type of that field, then we return
423 that result. */
424
425 /* New overloading code. */
426
427 typedef struct z_candidate z_candidate;
428
429 typedef struct candidate_warning candidate_warning;
430 struct candidate_warning {
431 z_candidate *loser;
432 candidate_warning *next;
433 };
434
435 /* Information for providing diagnostics about why overloading failed. */
436
437 enum rejection_reason_code {
438 rr_none,
439 rr_arity,
440 rr_explicit_conversion,
441 rr_template_conversion,
442 rr_arg_conversion,
443 rr_bad_arg_conversion,
444 rr_template_unification,
445 rr_template_instantiation,
446 rr_invalid_copy
447 };
448
449 struct conversion_info {
450 /* The index of the argument, 0-based. */
451 int n_arg;
452 /* The type of the actual argument. */
453 tree from_type;
454 /* The type of the formal argument. */
455 tree to_type;
456 };
457
458 struct rejection_reason {
459 enum rejection_reason_code code;
460 union {
461 /* Information about an arity mismatch. */
462 struct {
463 /* The expected number of arguments. */
464 int expected;
465 /* The actual number of arguments in the call. */
466 int actual;
467 /* Whether the call was a varargs call. */
468 bool call_varargs_p;
469 } arity;
470 /* Information about an argument conversion mismatch. */
471 struct conversion_info conversion;
472 /* Same, but for bad argument conversions. */
473 struct conversion_info bad_conversion;
474 /* Information about template unification failures. These are the
475 parameters passed to fn_type_unification. */
476 struct {
477 tree tmpl;
478 tree explicit_targs;
479 tree targs;
480 const tree *args;
481 unsigned int nargs;
482 tree return_type;
483 unification_kind_t strict;
484 int flags;
485 } template_unification;
486 /* Information about template instantiation failures. These are the
487 parameters passed to instantiate_template. */
488 struct {
489 tree tmpl;
490 tree targs;
491 } template_instantiation;
492 } u;
493 };
494
495 struct z_candidate {
496 /* The FUNCTION_DECL that will be called if this candidate is
497 selected by overload resolution. */
498 tree fn;
499 /* If not NULL_TREE, the first argument to use when calling this
500 function. */
501 tree first_arg;
502 /* The rest of the arguments to use when calling this function. If
503 there are no further arguments this may be NULL or it may be an
504 empty vector. */
505 const VEC(tree,gc) *args;
506 /* The implicit conversion sequences for each of the arguments to
507 FN. */
508 conversion **convs;
509 /* The number of implicit conversion sequences. */
510 size_t num_convs;
511 /* If FN is a user-defined conversion, the standard conversion
512 sequence from the type returned by FN to the desired destination
513 type. */
514 conversion *second_conv;
515 int viable;
516 struct rejection_reason *reason;
517 /* If FN is a member function, the binfo indicating the path used to
518 qualify the name of FN at the call site. This path is used to
519 determine whether or not FN is accessible if it is selected by
520 overload resolution. The DECL_CONTEXT of FN will always be a
521 (possibly improper) base of this binfo. */
522 tree access_path;
523 /* If FN is a non-static member function, the binfo indicating the
524 subobject to which the `this' pointer should be converted if FN
525 is selected by overload resolution. The type pointed to the by
526 the `this' pointer must correspond to the most derived class
527 indicated by the CONVERSION_PATH. */
528 tree conversion_path;
529 tree template_decl;
530 tree explicit_targs;
531 candidate_warning *warnings;
532 z_candidate *next;
533 };
534
535 /* Returns true iff T is a null pointer constant in the sense of
536 [conv.ptr]. */
537
538 bool
539 null_ptr_cst_p (tree t)
540 {
541 /* [conv.ptr]
542
543 A null pointer constant is an integral constant expression
544 (_expr.const_) rvalue of integer type that evaluates to zero or
545 an rvalue of type std::nullptr_t. */
546 if (NULLPTR_TYPE_P (TREE_TYPE (t)))
547 return true;
548 if (CP_INTEGRAL_TYPE_P (TREE_TYPE (t)))
549 {
550 /* Core issue 903 says only literal 0 is a null pointer constant. */
551 if (cxx_dialect < cxx0x)
552 {
553 t = integral_constant_value (t);
554 STRIP_NOPS (t);
555 }
556 if (integer_zerop (t) && !TREE_OVERFLOW (t))
557 return true;
558 }
559 return false;
560 }
561
562 /* Returns true iff T is a null member pointer value (4.11). */
563
564 bool
565 null_member_pointer_value_p (tree t)
566 {
567 tree type = TREE_TYPE (t);
568 if (!type)
569 return false;
570 else if (TYPE_PTRMEMFUNC_P (type))
571 return (TREE_CODE (t) == CONSTRUCTOR
572 && integer_zerop (CONSTRUCTOR_ELT (t, 0)->value));
573 else if (TYPE_PTRMEM_P (type))
574 return integer_all_onesp (t);
575 else
576 return false;
577 }
578
579 /* Returns nonzero if PARMLIST consists of only default parms,
580 ellipsis, and/or undeduced parameter packs. */
581
582 bool
583 sufficient_parms_p (const_tree parmlist)
584 {
585 for (; parmlist && parmlist != void_list_node;
586 parmlist = TREE_CHAIN (parmlist))
587 if (!TREE_PURPOSE (parmlist)
588 && !PACK_EXPANSION_P (TREE_VALUE (parmlist)))
589 return false;
590 return true;
591 }
592
593 /* Allocate N bytes of memory from the conversion obstack. The memory
594 is zeroed before being returned. */
595
596 static void *
597 conversion_obstack_alloc (size_t n)
598 {
599 void *p;
600 if (!conversion_obstack_initialized)
601 {
602 gcc_obstack_init (&conversion_obstack);
603 conversion_obstack_initialized = true;
604 }
605 p = obstack_alloc (&conversion_obstack, n);
606 memset (p, 0, n);
607 return p;
608 }
609
610 /* Allocate rejection reasons. */
611
612 static struct rejection_reason *
613 alloc_rejection (enum rejection_reason_code code)
614 {
615 struct rejection_reason *p;
616 p = (struct rejection_reason *) conversion_obstack_alloc (sizeof *p);
617 p->code = code;
618 return p;
619 }
620
621 static struct rejection_reason *
622 arity_rejection (tree first_arg, int expected, int actual)
623 {
624 struct rejection_reason *r = alloc_rejection (rr_arity);
625 int adjust = first_arg != NULL_TREE;
626 r->u.arity.expected = expected - adjust;
627 r->u.arity.actual = actual - adjust;
628 return r;
629 }
630
631 static struct rejection_reason *
632 arg_conversion_rejection (tree first_arg, int n_arg, tree from, tree to)
633 {
634 struct rejection_reason *r = alloc_rejection (rr_arg_conversion);
635 int adjust = first_arg != NULL_TREE;
636 r->u.conversion.n_arg = n_arg - adjust;
637 r->u.conversion.from_type = from;
638 r->u.conversion.to_type = to;
639 return r;
640 }
641
642 static struct rejection_reason *
643 bad_arg_conversion_rejection (tree first_arg, int n_arg, tree from, tree to)
644 {
645 struct rejection_reason *r = alloc_rejection (rr_bad_arg_conversion);
646 int adjust = first_arg != NULL_TREE;
647 r->u.bad_conversion.n_arg = n_arg - adjust;
648 r->u.bad_conversion.from_type = from;
649 r->u.bad_conversion.to_type = to;
650 return r;
651 }
652
653 static struct rejection_reason *
654 explicit_conversion_rejection (tree from, tree to)
655 {
656 struct rejection_reason *r = alloc_rejection (rr_explicit_conversion);
657 r->u.conversion.n_arg = 0;
658 r->u.conversion.from_type = from;
659 r->u.conversion.to_type = to;
660 return r;
661 }
662
663 static struct rejection_reason *
664 template_conversion_rejection (tree from, tree to)
665 {
666 struct rejection_reason *r = alloc_rejection (rr_template_conversion);
667 r->u.conversion.n_arg = 0;
668 r->u.conversion.from_type = from;
669 r->u.conversion.to_type = to;
670 return r;
671 }
672
673 static struct rejection_reason *
674 template_unification_rejection (tree tmpl, tree explicit_targs, tree targs,
675 const tree *args, unsigned int nargs,
676 tree return_type, unification_kind_t strict,
677 int flags)
678 {
679 size_t args_n_bytes = sizeof (*args) * nargs;
680 tree *args1 = (tree *) conversion_obstack_alloc (args_n_bytes);
681 struct rejection_reason *r = alloc_rejection (rr_template_unification);
682 r->u.template_unification.tmpl = tmpl;
683 r->u.template_unification.explicit_targs = explicit_targs;
684 r->u.template_unification.targs = targs;
685 /* Copy args to our own storage. */
686 memcpy (args1, args, args_n_bytes);
687 r->u.template_unification.args = args1;
688 r->u.template_unification.nargs = nargs;
689 r->u.template_unification.return_type = return_type;
690 r->u.template_unification.strict = strict;
691 r->u.template_unification.flags = flags;
692 return r;
693 }
694
695 static struct rejection_reason *
696 template_unification_error_rejection (void)
697 {
698 return alloc_rejection (rr_template_unification);
699 }
700
701 static struct rejection_reason *
702 template_instantiation_rejection (tree tmpl, tree targs)
703 {
704 struct rejection_reason *r = alloc_rejection (rr_template_instantiation);
705 r->u.template_instantiation.tmpl = tmpl;
706 r->u.template_instantiation.targs = targs;
707 return r;
708 }
709
710 static struct rejection_reason *
711 invalid_copy_with_fn_template_rejection (void)
712 {
713 struct rejection_reason *r = alloc_rejection (rr_invalid_copy);
714 return r;
715 }
716
717 /* Dynamically allocate a conversion. */
718
719 static conversion *
720 alloc_conversion (conversion_kind kind)
721 {
722 conversion *c;
723 c = (conversion *) conversion_obstack_alloc (sizeof (conversion));
724 c->kind = kind;
725 return c;
726 }
727
728 #ifdef ENABLE_CHECKING
729
730 /* Make sure that all memory on the conversion obstack has been
731 freed. */
732
733 void
734 validate_conversion_obstack (void)
735 {
736 if (conversion_obstack_initialized)
737 gcc_assert ((obstack_next_free (&conversion_obstack)
738 == obstack_base (&conversion_obstack)));
739 }
740
741 #endif /* ENABLE_CHECKING */
742
743 /* Dynamically allocate an array of N conversions. */
744
745 static conversion **
746 alloc_conversions (size_t n)
747 {
748 return (conversion **) conversion_obstack_alloc (n * sizeof (conversion *));
749 }
750
751 static conversion *
752 build_conv (conversion_kind code, tree type, conversion *from)
753 {
754 conversion *t;
755 conversion_rank rank = CONVERSION_RANK (from);
756
757 /* Note that the caller is responsible for filling in t->cand for
758 user-defined conversions. */
759 t = alloc_conversion (code);
760 t->type = type;
761 t->u.next = from;
762
763 switch (code)
764 {
765 case ck_ptr:
766 case ck_pmem:
767 case ck_base:
768 case ck_std:
769 if (rank < cr_std)
770 rank = cr_std;
771 break;
772
773 case ck_qual:
774 if (rank < cr_exact)
775 rank = cr_exact;
776 break;
777
778 default:
779 break;
780 }
781 t->rank = rank;
782 t->user_conv_p = (code == ck_user || from->user_conv_p);
783 t->bad_p = from->bad_p;
784 t->base_p = false;
785 return t;
786 }
787
788 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
789 specialization of std::initializer_list<T>, if such a conversion is
790 possible. */
791
792 static conversion *
793 build_list_conv (tree type, tree ctor, int flags)
794 {
795 tree elttype = TREE_VEC_ELT (CLASSTYPE_TI_ARGS (type), 0);
796 unsigned len = CONSTRUCTOR_NELTS (ctor);
797 conversion **subconvs = alloc_conversions (len);
798 conversion *t;
799 unsigned i;
800 tree val;
801
802 /* Within a list-initialization we can have more user-defined
803 conversions. */
804 flags &= ~LOOKUP_NO_CONVERSION;
805 /* But no narrowing conversions. */
806 flags |= LOOKUP_NO_NARROWING;
807
808 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), i, val)
809 {
810 conversion *sub
811 = implicit_conversion (elttype, TREE_TYPE (val), val,
812 false, flags);
813 if (sub == NULL)
814 return NULL;
815
816 subconvs[i] = sub;
817 }
818
819 t = alloc_conversion (ck_list);
820 t->type = type;
821 t->u.list = subconvs;
822 t->rank = cr_exact;
823
824 for (i = 0; i < len; ++i)
825 {
826 conversion *sub = subconvs[i];
827 if (sub->rank > t->rank)
828 t->rank = sub->rank;
829 if (sub->user_conv_p)
830 t->user_conv_p = true;
831 if (sub->bad_p)
832 t->bad_p = true;
833 }
834
835 return t;
836 }
837
838 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
839 is a valid aggregate initializer for array type ATYPE. */
840
841 static bool
842 can_convert_array (tree atype, tree ctor, int flags)
843 {
844 unsigned i;
845 tree elttype = TREE_TYPE (atype);
846 for (i = 0; i < CONSTRUCTOR_NELTS (ctor); ++i)
847 {
848 tree val = CONSTRUCTOR_ELT (ctor, i)->value;
849 bool ok;
850 if (TREE_CODE (elttype) == ARRAY_TYPE
851 && TREE_CODE (val) == CONSTRUCTOR)
852 ok = can_convert_array (elttype, val, flags);
853 else
854 ok = can_convert_arg (elttype, TREE_TYPE (val), val, flags);
855 if (!ok)
856 return false;
857 }
858 return true;
859 }
860
861 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
862 aggregate class, if such a conversion is possible. */
863
864 static conversion *
865 build_aggr_conv (tree type, tree ctor, int flags)
866 {
867 unsigned HOST_WIDE_INT i = 0;
868 conversion *c;
869 tree field = next_initializable_field (TYPE_FIELDS (type));
870 tree empty_ctor = NULL_TREE;
871
872 for (; field; field = next_initializable_field (DECL_CHAIN (field)))
873 {
874 tree ftype = TREE_TYPE (field);
875 tree val;
876 bool ok;
877
878 if (i < CONSTRUCTOR_NELTS (ctor))
879 val = CONSTRUCTOR_ELT (ctor, i)->value;
880 else
881 {
882 if (empty_ctor == NULL_TREE)
883 empty_ctor = build_constructor (init_list_type_node, NULL);
884 val = empty_ctor;
885 }
886 ++i;
887
888 if (TREE_CODE (ftype) == ARRAY_TYPE
889 && TREE_CODE (val) == CONSTRUCTOR)
890 ok = can_convert_array (ftype, val, flags);
891 else
892 ok = can_convert_arg (ftype, TREE_TYPE (val), val, flags);
893
894 if (!ok)
895 return NULL;
896
897 if (TREE_CODE (type) == UNION_TYPE)
898 break;
899 }
900
901 if (i < CONSTRUCTOR_NELTS (ctor))
902 return NULL;
903
904 c = alloc_conversion (ck_aggr);
905 c->type = type;
906 c->rank = cr_exact;
907 c->user_conv_p = true;
908 c->u.next = NULL;
909 return c;
910 }
911
912 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
913 array type, if such a conversion is possible. */
914
915 static conversion *
916 build_array_conv (tree type, tree ctor, int flags)
917 {
918 conversion *c;
919 unsigned HOST_WIDE_INT len = CONSTRUCTOR_NELTS (ctor);
920 tree elttype = TREE_TYPE (type);
921 unsigned i;
922 tree val;
923 bool bad = false;
924 bool user = false;
925 enum conversion_rank rank = cr_exact;
926
927 if (TYPE_DOMAIN (type))
928 {
929 unsigned HOST_WIDE_INT alen = tree_low_cst (array_type_nelts_top (type), 1);
930 if (alen < len)
931 return NULL;
932 }
933
934 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), i, val)
935 {
936 conversion *sub
937 = implicit_conversion (elttype, TREE_TYPE (val), val,
938 false, flags);
939 if (sub == NULL)
940 return NULL;
941
942 if (sub->rank > rank)
943 rank = sub->rank;
944 if (sub->user_conv_p)
945 user = true;
946 if (sub->bad_p)
947 bad = true;
948 }
949
950 c = alloc_conversion (ck_aggr);
951 c->type = type;
952 c->rank = rank;
953 c->user_conv_p = user;
954 c->bad_p = bad;
955 c->u.next = NULL;
956 return c;
957 }
958
959 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
960 complex type, if such a conversion is possible. */
961
962 static conversion *
963 build_complex_conv (tree type, tree ctor, int flags)
964 {
965 conversion *c;
966 unsigned HOST_WIDE_INT len = CONSTRUCTOR_NELTS (ctor);
967 tree elttype = TREE_TYPE (type);
968 unsigned i;
969 tree val;
970 bool bad = false;
971 bool user = false;
972 enum conversion_rank rank = cr_exact;
973
974 if (len != 2)
975 return NULL;
976
977 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), i, val)
978 {
979 conversion *sub
980 = implicit_conversion (elttype, TREE_TYPE (val), val,
981 false, flags);
982 if (sub == NULL)
983 return NULL;
984
985 if (sub->rank > rank)
986 rank = sub->rank;
987 if (sub->user_conv_p)
988 user = true;
989 if (sub->bad_p)
990 bad = true;
991 }
992
993 c = alloc_conversion (ck_aggr);
994 c->type = type;
995 c->rank = rank;
996 c->user_conv_p = user;
997 c->bad_p = bad;
998 c->u.next = NULL;
999 return c;
1000 }
1001
1002 /* Build a representation of the identity conversion from EXPR to
1003 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1004
1005 static conversion *
1006 build_identity_conv (tree type, tree expr)
1007 {
1008 conversion *c;
1009
1010 c = alloc_conversion (ck_identity);
1011 c->type = type;
1012 c->u.expr = expr;
1013
1014 return c;
1015 }
1016
1017 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1018 were multiple user-defined conversions to accomplish the job.
1019 Build a conversion that indicates that ambiguity. */
1020
1021 static conversion *
1022 build_ambiguous_conv (tree type, tree expr)
1023 {
1024 conversion *c;
1025
1026 c = alloc_conversion (ck_ambig);
1027 c->type = type;
1028 c->u.expr = expr;
1029
1030 return c;
1031 }
1032
1033 tree
1034 strip_top_quals (tree t)
1035 {
1036 if (TREE_CODE (t) == ARRAY_TYPE)
1037 return t;
1038 return cp_build_qualified_type (t, 0);
1039 }
1040
1041 /* Returns the standard conversion path (see [conv]) from type FROM to type
1042 TO, if any. For proper handling of null pointer constants, you must
1043 also pass the expression EXPR to convert from. If C_CAST_P is true,
1044 this conversion is coming from a C-style cast. */
1045
1046 static conversion *
1047 standard_conversion (tree to, tree from, tree expr, bool c_cast_p,
1048 int flags)
1049 {
1050 enum tree_code fcode, tcode;
1051 conversion *conv;
1052 bool fromref = false;
1053 tree qualified_to;
1054
1055 to = non_reference (to);
1056 if (TREE_CODE (from) == REFERENCE_TYPE)
1057 {
1058 fromref = true;
1059 from = TREE_TYPE (from);
1060 }
1061 qualified_to = to;
1062 to = strip_top_quals (to);
1063 from = strip_top_quals (from);
1064
1065 if ((TYPE_PTRFN_P (to) || TYPE_PTRMEMFUNC_P (to))
1066 && expr && type_unknown_p (expr))
1067 {
1068 tsubst_flags_t tflags = tf_conv;
1069 if (!(flags & LOOKUP_PROTECT))
1070 tflags |= tf_no_access_control;
1071 expr = instantiate_type (to, expr, tflags);
1072 if (expr == error_mark_node)
1073 return NULL;
1074 from = TREE_TYPE (expr);
1075 }
1076
1077 fcode = TREE_CODE (from);
1078 tcode = TREE_CODE (to);
1079
1080 conv = build_identity_conv (from, expr);
1081 if (fcode == FUNCTION_TYPE || fcode == ARRAY_TYPE)
1082 {
1083 from = type_decays_to (from);
1084 fcode = TREE_CODE (from);
1085 conv = build_conv (ck_lvalue, from, conv);
1086 }
1087 else if (fromref || (expr && lvalue_p (expr)))
1088 {
1089 if (expr)
1090 {
1091 tree bitfield_type;
1092 bitfield_type = is_bitfield_expr_with_lowered_type (expr);
1093 if (bitfield_type)
1094 {
1095 from = strip_top_quals (bitfield_type);
1096 fcode = TREE_CODE (from);
1097 }
1098 }
1099 conv = build_conv (ck_rvalue, from, conv);
1100 if (flags & LOOKUP_PREFER_RVALUE)
1101 conv->rvaluedness_matches_p = true;
1102 }
1103
1104 /* Allow conversion between `__complex__' data types. */
1105 if (tcode == COMPLEX_TYPE && fcode == COMPLEX_TYPE)
1106 {
1107 /* The standard conversion sequence to convert FROM to TO is
1108 the standard conversion sequence to perform componentwise
1109 conversion. */
1110 conversion *part_conv = standard_conversion
1111 (TREE_TYPE (to), TREE_TYPE (from), NULL_TREE, c_cast_p, flags);
1112
1113 if (part_conv)
1114 {
1115 conv = build_conv (part_conv->kind, to, conv);
1116 conv->rank = part_conv->rank;
1117 }
1118 else
1119 conv = NULL;
1120
1121 return conv;
1122 }
1123
1124 if (same_type_p (from, to))
1125 {
1126 if (CLASS_TYPE_P (to) && conv->kind == ck_rvalue)
1127 conv->type = qualified_to;
1128 return conv;
1129 }
1130
1131 /* [conv.ptr]
1132 A null pointer constant can be converted to a pointer type; ... A
1133 null pointer constant of integral type can be converted to an
1134 rvalue of type std::nullptr_t. */
1135 if ((tcode == POINTER_TYPE || TYPE_PTR_TO_MEMBER_P (to)
1136 || NULLPTR_TYPE_P (to))
1137 && expr && null_ptr_cst_p (expr))
1138 conv = build_conv (ck_std, to, conv);
1139 else if ((tcode == INTEGER_TYPE && fcode == POINTER_TYPE)
1140 || (tcode == POINTER_TYPE && fcode == INTEGER_TYPE))
1141 {
1142 /* For backwards brain damage compatibility, allow interconversion of
1143 pointers and integers with a pedwarn. */
1144 conv = build_conv (ck_std, to, conv);
1145 conv->bad_p = true;
1146 }
1147 else if (UNSCOPED_ENUM_P (to) && fcode == INTEGER_TYPE)
1148 {
1149 /* For backwards brain damage compatibility, allow interconversion of
1150 enums and integers with a pedwarn. */
1151 conv = build_conv (ck_std, to, conv);
1152 conv->bad_p = true;
1153 }
1154 else if ((tcode == POINTER_TYPE && fcode == POINTER_TYPE)
1155 || (TYPE_PTRMEM_P (to) && TYPE_PTRMEM_P (from)))
1156 {
1157 tree to_pointee;
1158 tree from_pointee;
1159
1160 if (tcode == POINTER_TYPE
1161 && same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (from),
1162 TREE_TYPE (to)))
1163 ;
1164 else if (VOID_TYPE_P (TREE_TYPE (to))
1165 && !TYPE_PTRMEM_P (from)
1166 && TREE_CODE (TREE_TYPE (from)) != FUNCTION_TYPE)
1167 {
1168 tree nfrom = TREE_TYPE (from);
1169 from = build_pointer_type
1170 (cp_build_qualified_type (void_type_node,
1171 cp_type_quals (nfrom)));
1172 conv = build_conv (ck_ptr, from, conv);
1173 }
1174 else if (TYPE_PTRMEM_P (from))
1175 {
1176 tree fbase = TYPE_PTRMEM_CLASS_TYPE (from);
1177 tree tbase = TYPE_PTRMEM_CLASS_TYPE (to);
1178
1179 if (DERIVED_FROM_P (fbase, tbase)
1180 && (same_type_ignoring_top_level_qualifiers_p
1181 (TYPE_PTRMEM_POINTED_TO_TYPE (from),
1182 TYPE_PTRMEM_POINTED_TO_TYPE (to))))
1183 {
1184 from = build_ptrmem_type (tbase,
1185 TYPE_PTRMEM_POINTED_TO_TYPE (from));
1186 conv = build_conv (ck_pmem, from, conv);
1187 }
1188 else if (!same_type_p (fbase, tbase))
1189 return NULL;
1190 }
1191 else if (CLASS_TYPE_P (TREE_TYPE (from))
1192 && CLASS_TYPE_P (TREE_TYPE (to))
1193 /* [conv.ptr]
1194
1195 An rvalue of type "pointer to cv D," where D is a
1196 class type, can be converted to an rvalue of type
1197 "pointer to cv B," where B is a base class (clause
1198 _class.derived_) of D. If B is an inaccessible
1199 (clause _class.access_) or ambiguous
1200 (_class.member.lookup_) base class of D, a program
1201 that necessitates this conversion is ill-formed.
1202 Therefore, we use DERIVED_FROM_P, and do not check
1203 access or uniqueness. */
1204 && DERIVED_FROM_P (TREE_TYPE (to), TREE_TYPE (from)))
1205 {
1206 from =
1207 cp_build_qualified_type (TREE_TYPE (to),
1208 cp_type_quals (TREE_TYPE (from)));
1209 from = build_pointer_type (from);
1210 conv = build_conv (ck_ptr, from, conv);
1211 conv->base_p = true;
1212 }
1213
1214 if (tcode == POINTER_TYPE)
1215 {
1216 to_pointee = TREE_TYPE (to);
1217 from_pointee = TREE_TYPE (from);
1218 }
1219 else
1220 {
1221 to_pointee = TYPE_PTRMEM_POINTED_TO_TYPE (to);
1222 from_pointee = TYPE_PTRMEM_POINTED_TO_TYPE (from);
1223 }
1224
1225 if (same_type_p (from, to))
1226 /* OK */;
1227 else if (c_cast_p && comp_ptr_ttypes_const (to, from))
1228 /* In a C-style cast, we ignore CV-qualification because we
1229 are allowed to perform a static_cast followed by a
1230 const_cast. */
1231 conv = build_conv (ck_qual, to, conv);
1232 else if (!c_cast_p && comp_ptr_ttypes (to_pointee, from_pointee))
1233 conv = build_conv (ck_qual, to, conv);
1234 else if (expr && string_conv_p (to, expr, 0))
1235 /* converting from string constant to char *. */
1236 conv = build_conv (ck_qual, to, conv);
1237 /* Allow conversions among compatible ObjC pointer types (base
1238 conversions have been already handled above). */
1239 else if (c_dialect_objc ()
1240 && objc_compare_types (to, from, -4, NULL_TREE))
1241 conv = build_conv (ck_ptr, to, conv);
1242 else if (ptr_reasonably_similar (to_pointee, from_pointee))
1243 {
1244 conv = build_conv (ck_ptr, to, conv);
1245 conv->bad_p = true;
1246 }
1247 else
1248 return NULL;
1249
1250 from = to;
1251 }
1252 else if (TYPE_PTRMEMFUNC_P (to) && TYPE_PTRMEMFUNC_P (from))
1253 {
1254 tree fromfn = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (from));
1255 tree tofn = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (to));
1256 tree fbase = class_of_this_parm (fromfn);
1257 tree tbase = class_of_this_parm (tofn);
1258
1259 if (!DERIVED_FROM_P (fbase, tbase)
1260 || !same_type_p (TREE_TYPE (fromfn), TREE_TYPE (tofn))
1261 || !compparms (TREE_CHAIN (TYPE_ARG_TYPES (fromfn)),
1262 TREE_CHAIN (TYPE_ARG_TYPES (tofn)))
1263 || cp_type_quals (fbase) != cp_type_quals (tbase))
1264 return NULL;
1265
1266 from = build_memfn_type (fromfn, tbase, cp_type_quals (tbase));
1267 from = build_ptrmemfunc_type (build_pointer_type (from));
1268 conv = build_conv (ck_pmem, from, conv);
1269 conv->base_p = true;
1270 }
1271 else if (tcode == BOOLEAN_TYPE)
1272 {
1273 /* [conv.bool]
1274
1275 An rvalue of arithmetic, unscoped enumeration, pointer, or
1276 pointer to member type can be converted to an rvalue of type
1277 bool. ... An rvalue of type std::nullptr_t can be converted
1278 to an rvalue of type bool; */
1279 if (ARITHMETIC_TYPE_P (from)
1280 || UNSCOPED_ENUM_P (from)
1281 || fcode == POINTER_TYPE
1282 || TYPE_PTR_TO_MEMBER_P (from)
1283 || NULLPTR_TYPE_P (from))
1284 {
1285 conv = build_conv (ck_std, to, conv);
1286 if (fcode == POINTER_TYPE
1287 || TYPE_PTRMEM_P (from)
1288 || (TYPE_PTRMEMFUNC_P (from)
1289 && conv->rank < cr_pbool)
1290 || NULLPTR_TYPE_P (from))
1291 conv->rank = cr_pbool;
1292 return conv;
1293 }
1294
1295 return NULL;
1296 }
1297 /* We don't check for ENUMERAL_TYPE here because there are no standard
1298 conversions to enum type. */
1299 /* As an extension, allow conversion to complex type. */
1300 else if (ARITHMETIC_TYPE_P (to))
1301 {
1302 if (! (INTEGRAL_CODE_P (fcode) || fcode == REAL_TYPE)
1303 || SCOPED_ENUM_P (from))
1304 return NULL;
1305 conv = build_conv (ck_std, to, conv);
1306
1307 /* Give this a better rank if it's a promotion. */
1308 if (same_type_p (to, type_promotes_to (from))
1309 && conv->u.next->rank <= cr_promotion)
1310 conv->rank = cr_promotion;
1311 }
1312 else if (fcode == VECTOR_TYPE && tcode == VECTOR_TYPE
1313 && vector_types_convertible_p (from, to, false))
1314 return build_conv (ck_std, to, conv);
1315 else if (MAYBE_CLASS_TYPE_P (to) && MAYBE_CLASS_TYPE_P (from)
1316 && is_properly_derived_from (from, to))
1317 {
1318 if (conv->kind == ck_rvalue)
1319 conv = conv->u.next;
1320 conv = build_conv (ck_base, to, conv);
1321 /* The derived-to-base conversion indicates the initialization
1322 of a parameter with base type from an object of a derived
1323 type. A temporary object is created to hold the result of
1324 the conversion unless we're binding directly to a reference. */
1325 conv->need_temporary_p = !(flags & LOOKUP_NO_TEMP_BIND);
1326 }
1327 else
1328 return NULL;
1329
1330 if (flags & LOOKUP_NO_NARROWING)
1331 conv->check_narrowing = true;
1332
1333 return conv;
1334 }
1335
1336 /* Returns nonzero if T1 is reference-related to T2. */
1337
1338 bool
1339 reference_related_p (tree t1, tree t2)
1340 {
1341 if (t1 == error_mark_node || t2 == error_mark_node)
1342 return false;
1343
1344 t1 = TYPE_MAIN_VARIANT (t1);
1345 t2 = TYPE_MAIN_VARIANT (t2);
1346
1347 /* [dcl.init.ref]
1348
1349 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1350 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1351 of T2. */
1352 return (same_type_p (t1, t2)
1353 || (CLASS_TYPE_P (t1) && CLASS_TYPE_P (t2)
1354 && DERIVED_FROM_P (t1, t2)));
1355 }
1356
1357 /* Returns nonzero if T1 is reference-compatible with T2. */
1358
1359 static bool
1360 reference_compatible_p (tree t1, tree t2)
1361 {
1362 /* [dcl.init.ref]
1363
1364 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1365 reference-related to T2 and cv1 is the same cv-qualification as,
1366 or greater cv-qualification than, cv2. */
1367 return (reference_related_p (t1, t2)
1368 && at_least_as_qualified_p (t1, t2));
1369 }
1370
1371 /* A reference of the indicated TYPE is being bound directly to the
1372 expression represented by the implicit conversion sequence CONV.
1373 Return a conversion sequence for this binding. */
1374
1375 static conversion *
1376 direct_reference_binding (tree type, conversion *conv)
1377 {
1378 tree t;
1379
1380 gcc_assert (TREE_CODE (type) == REFERENCE_TYPE);
1381 gcc_assert (TREE_CODE (conv->type) != REFERENCE_TYPE);
1382
1383 t = TREE_TYPE (type);
1384
1385 /* [over.ics.rank]
1386
1387 When a parameter of reference type binds directly
1388 (_dcl.init.ref_) to an argument expression, the implicit
1389 conversion sequence is the identity conversion, unless the
1390 argument expression has a type that is a derived class of the
1391 parameter type, in which case the implicit conversion sequence is
1392 a derived-to-base Conversion.
1393
1394 If the parameter binds directly to the result of applying a
1395 conversion function to the argument expression, the implicit
1396 conversion sequence is a user-defined conversion sequence
1397 (_over.ics.user_), with the second standard conversion sequence
1398 either an identity conversion or, if the conversion function
1399 returns an entity of a type that is a derived class of the
1400 parameter type, a derived-to-base conversion. */
1401 if (!same_type_ignoring_top_level_qualifiers_p (t, conv->type))
1402 {
1403 /* Represent the derived-to-base conversion. */
1404 conv = build_conv (ck_base, t, conv);
1405 /* We will actually be binding to the base-class subobject in
1406 the derived class, so we mark this conversion appropriately.
1407 That way, convert_like knows not to generate a temporary. */
1408 conv->need_temporary_p = false;
1409 }
1410 return build_conv (ck_ref_bind, type, conv);
1411 }
1412
1413 /* Returns the conversion path from type FROM to reference type TO for
1414 purposes of reference binding. For lvalue binding, either pass a
1415 reference type to FROM or an lvalue expression to EXPR. If the
1416 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1417 the conversion returned. If C_CAST_P is true, this
1418 conversion is coming from a C-style cast. */
1419
1420 static conversion *
1421 reference_binding (tree rto, tree rfrom, tree expr, bool c_cast_p, int flags)
1422 {
1423 conversion *conv = NULL;
1424 tree to = TREE_TYPE (rto);
1425 tree from = rfrom;
1426 tree tfrom;
1427 bool related_p;
1428 bool compatible_p;
1429 cp_lvalue_kind gl_kind;
1430 bool is_lvalue;
1431
1432 if (TREE_CODE (to) == FUNCTION_TYPE && expr && type_unknown_p (expr))
1433 {
1434 expr = instantiate_type (to, expr, tf_none);
1435 if (expr == error_mark_node)
1436 return NULL;
1437 from = TREE_TYPE (expr);
1438 }
1439
1440 if (expr && BRACE_ENCLOSED_INITIALIZER_P (expr))
1441 {
1442 maybe_warn_cpp0x (CPP0X_INITIALIZER_LISTS);
1443 conv = implicit_conversion (to, from, expr, c_cast_p,
1444 flags);
1445 if (!CLASS_TYPE_P (to)
1446 && CONSTRUCTOR_NELTS (expr) == 1)
1447 {
1448 expr = CONSTRUCTOR_ELT (expr, 0)->value;
1449 if (error_operand_p (expr))
1450 return NULL;
1451 from = TREE_TYPE (expr);
1452 }
1453 }
1454
1455 if (TREE_CODE (from) == REFERENCE_TYPE)
1456 {
1457 from = TREE_TYPE (from);
1458 if (!TYPE_REF_IS_RVALUE (rfrom)
1459 || TREE_CODE (from) == FUNCTION_TYPE)
1460 gl_kind = clk_ordinary;
1461 else
1462 gl_kind = clk_rvalueref;
1463 }
1464 else if (expr)
1465 {
1466 gl_kind = lvalue_kind (expr);
1467 if (gl_kind & clk_class)
1468 /* A class prvalue is not a glvalue. */
1469 gl_kind = clk_none;
1470 }
1471 else
1472 gl_kind = clk_none;
1473 is_lvalue = gl_kind && !(gl_kind & clk_rvalueref);
1474
1475 tfrom = from;
1476 if ((gl_kind & clk_bitfield) != 0)
1477 tfrom = unlowered_expr_type (expr);
1478
1479 /* Figure out whether or not the types are reference-related and
1480 reference compatible. We have do do this after stripping
1481 references from FROM. */
1482 related_p = reference_related_p (to, tfrom);
1483 /* If this is a C cast, first convert to an appropriately qualified
1484 type, so that we can later do a const_cast to the desired type. */
1485 if (related_p && c_cast_p
1486 && !at_least_as_qualified_p (to, tfrom))
1487 to = cp_build_qualified_type (to, cp_type_quals (tfrom));
1488 compatible_p = reference_compatible_p (to, tfrom);
1489
1490 /* Directly bind reference when target expression's type is compatible with
1491 the reference and expression is an lvalue. In DR391, the wording in
1492 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1493 const and rvalue references to rvalues of compatible class type.
1494 We should also do direct bindings for non-class xvalues. */
1495 if (compatible_p
1496 && (is_lvalue
1497 || (((CP_TYPE_CONST_NON_VOLATILE_P (to)
1498 && !(flags & LOOKUP_NO_RVAL_BIND))
1499 || TYPE_REF_IS_RVALUE (rto))
1500 && (gl_kind
1501 || (!(flags & LOOKUP_NO_TEMP_BIND)
1502 && (CLASS_TYPE_P (from)
1503 || TREE_CODE (from) == ARRAY_TYPE))))))
1504 {
1505 /* [dcl.init.ref]
1506
1507 If the initializer expression
1508
1509 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1510 is reference-compatible with "cv2 T2,"
1511
1512 the reference is bound directly to the initializer expression
1513 lvalue.
1514
1515 [...]
1516 If the initializer expression is an rvalue, with T2 a class type,
1517 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1518 is bound to the object represented by the rvalue or to a sub-object
1519 within that object. */
1520
1521 conv = build_identity_conv (tfrom, expr);
1522 conv = direct_reference_binding (rto, conv);
1523
1524 if (flags & LOOKUP_PREFER_RVALUE)
1525 /* The top-level caller requested that we pretend that the lvalue
1526 be treated as an rvalue. */
1527 conv->rvaluedness_matches_p = TYPE_REF_IS_RVALUE (rto);
1528 else if (TREE_CODE (rfrom) == REFERENCE_TYPE)
1529 /* Handle rvalue reference to function properly. */
1530 conv->rvaluedness_matches_p
1531 = (TYPE_REF_IS_RVALUE (rto) == TYPE_REF_IS_RVALUE (rfrom));
1532 else
1533 conv->rvaluedness_matches_p
1534 = (TYPE_REF_IS_RVALUE (rto) == !is_lvalue);
1535
1536 if ((gl_kind & clk_bitfield) != 0
1537 || ((gl_kind & clk_packed) != 0 && !TYPE_PACKED (to)))
1538 /* For the purposes of overload resolution, we ignore the fact
1539 this expression is a bitfield or packed field. (In particular,
1540 [over.ics.ref] says specifically that a function with a
1541 non-const reference parameter is viable even if the
1542 argument is a bitfield.)
1543
1544 However, when we actually call the function we must create
1545 a temporary to which to bind the reference. If the
1546 reference is volatile, or isn't const, then we cannot make
1547 a temporary, so we just issue an error when the conversion
1548 actually occurs. */
1549 conv->need_temporary_p = true;
1550
1551 /* Don't allow binding of lvalues (other than function lvalues) to
1552 rvalue references. */
1553 if (is_lvalue && TYPE_REF_IS_RVALUE (rto)
1554 && TREE_CODE (to) != FUNCTION_TYPE
1555 && !(flags & LOOKUP_PREFER_RVALUE))
1556 conv->bad_p = true;
1557
1558 return conv;
1559 }
1560 /* [class.conv.fct] A conversion function is never used to convert a
1561 (possibly cv-qualified) object to the (possibly cv-qualified) same
1562 object type (or a reference to it), to a (possibly cv-qualified) base
1563 class of that type (or a reference to it).... */
1564 else if (CLASS_TYPE_P (from) && !related_p
1565 && !(flags & LOOKUP_NO_CONVERSION))
1566 {
1567 /* [dcl.init.ref]
1568
1569 If the initializer expression
1570
1571 -- has a class type (i.e., T2 is a class type) can be
1572 implicitly converted to an lvalue of type "cv3 T3," where
1573 "cv1 T1" is reference-compatible with "cv3 T3". (this
1574 conversion is selected by enumerating the applicable
1575 conversion functions (_over.match.ref_) and choosing the
1576 best one through overload resolution. (_over.match_).
1577
1578 the reference is bound to the lvalue result of the conversion
1579 in the second case. */
1580 z_candidate *cand = build_user_type_conversion_1 (rto, expr, flags);
1581 if (cand)
1582 return cand->second_conv;
1583 }
1584
1585 /* From this point on, we conceptually need temporaries, even if we
1586 elide them. Only the cases above are "direct bindings". */
1587 if (flags & LOOKUP_NO_TEMP_BIND)
1588 return NULL;
1589
1590 /* [over.ics.rank]
1591
1592 When a parameter of reference type is not bound directly to an
1593 argument expression, the conversion sequence is the one required
1594 to convert the argument expression to the underlying type of the
1595 reference according to _over.best.ics_. Conceptually, this
1596 conversion sequence corresponds to copy-initializing a temporary
1597 of the underlying type with the argument expression. Any
1598 difference in top-level cv-qualification is subsumed by the
1599 initialization itself and does not constitute a conversion. */
1600
1601 /* [dcl.init.ref]
1602
1603 Otherwise, the reference shall be to a non-volatile const type.
1604
1605 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1606 if (!CP_TYPE_CONST_NON_VOLATILE_P (to) && !TYPE_REF_IS_RVALUE (rto))
1607 return NULL;
1608
1609 /* [dcl.init.ref]
1610
1611 Otherwise, a temporary of type "cv1 T1" is created and
1612 initialized from the initializer expression using the rules for a
1613 non-reference copy initialization. If T1 is reference-related to
1614 T2, cv1 must be the same cv-qualification as, or greater
1615 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1616 if (related_p && !at_least_as_qualified_p (to, from))
1617 return NULL;
1618
1619 /* We're generating a temporary now, but don't bind any more in the
1620 conversion (specifically, don't slice the temporary returned by a
1621 conversion operator). */
1622 flags |= LOOKUP_NO_TEMP_BIND;
1623
1624 /* Core issue 899: When [copy-]initializing a temporary to be bound
1625 to the first parameter of a copy constructor (12.8) called with
1626 a single argument in the context of direct-initialization,
1627 explicit conversion functions are also considered.
1628
1629 So don't set LOOKUP_ONLYCONVERTING in that case. */
1630 if (!(flags & LOOKUP_COPY_PARM))
1631 flags |= LOOKUP_ONLYCONVERTING;
1632
1633 if (!conv)
1634 conv = implicit_conversion (to, from, expr, c_cast_p,
1635 flags);
1636 if (!conv)
1637 return NULL;
1638
1639 conv = build_conv (ck_ref_bind, rto, conv);
1640 /* This reference binding, unlike those above, requires the
1641 creation of a temporary. */
1642 conv->need_temporary_p = true;
1643 conv->rvaluedness_matches_p = TYPE_REF_IS_RVALUE (rto);
1644
1645 return conv;
1646 }
1647
1648 /* Returns the implicit conversion sequence (see [over.ics]) from type
1649 FROM to type TO. The optional expression EXPR may affect the
1650 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1651 true, this conversion is coming from a C-style cast. */
1652
1653 static conversion *
1654 implicit_conversion (tree to, tree from, tree expr, bool c_cast_p,
1655 int flags)
1656 {
1657 conversion *conv;
1658
1659 if (from == error_mark_node || to == error_mark_node
1660 || expr == error_mark_node)
1661 return NULL;
1662
1663 /* Other flags only apply to the primary function in overload
1664 resolution, or after we've chosen one. */
1665 flags &= (LOOKUP_ONLYCONVERTING|LOOKUP_NO_CONVERSION|LOOKUP_COPY_PARM
1666 |LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND|LOOKUP_PREFER_RVALUE
1667 |LOOKUP_NO_NARROWING|LOOKUP_PROTECT);
1668
1669 if (TREE_CODE (to) == REFERENCE_TYPE)
1670 conv = reference_binding (to, from, expr, c_cast_p, flags);
1671 else
1672 conv = standard_conversion (to, from, expr, c_cast_p, flags);
1673
1674 if (conv)
1675 return conv;
1676
1677 if (expr && BRACE_ENCLOSED_INITIALIZER_P (expr))
1678 {
1679 if (is_std_init_list (to))
1680 return build_list_conv (to, expr, flags);
1681
1682 /* As an extension, allow list-initialization of _Complex. */
1683 if (TREE_CODE (to) == COMPLEX_TYPE)
1684 {
1685 conv = build_complex_conv (to, expr, flags);
1686 if (conv)
1687 return conv;
1688 }
1689
1690 /* Allow conversion from an initializer-list with one element to a
1691 scalar type. */
1692 if (SCALAR_TYPE_P (to))
1693 {
1694 int nelts = CONSTRUCTOR_NELTS (expr);
1695 tree elt;
1696
1697 if (nelts == 0)
1698 elt = build_value_init (to, tf_none);
1699 else if (nelts == 1)
1700 elt = CONSTRUCTOR_ELT (expr, 0)->value;
1701 else
1702 elt = error_mark_node;
1703
1704 conv = implicit_conversion (to, TREE_TYPE (elt), elt,
1705 c_cast_p, flags);
1706 if (conv)
1707 {
1708 conv->check_narrowing = true;
1709 if (BRACE_ENCLOSED_INITIALIZER_P (elt))
1710 /* Too many levels of braces, i.e. '{{1}}'. */
1711 conv->bad_p = true;
1712 return conv;
1713 }
1714 }
1715 else if (TREE_CODE (to) == ARRAY_TYPE)
1716 return build_array_conv (to, expr, flags);
1717 }
1718
1719 if (expr != NULL_TREE
1720 && (MAYBE_CLASS_TYPE_P (from)
1721 || MAYBE_CLASS_TYPE_P (to))
1722 && (flags & LOOKUP_NO_CONVERSION) == 0)
1723 {
1724 struct z_candidate *cand;
1725
1726 if (CLASS_TYPE_P (to)
1727 && BRACE_ENCLOSED_INITIALIZER_P (expr)
1728 && !CLASSTYPE_NON_AGGREGATE (complete_type (to)))
1729 return build_aggr_conv (to, expr, flags);
1730
1731 cand = build_user_type_conversion_1 (to, expr, flags);
1732 if (cand)
1733 conv = cand->second_conv;
1734
1735 /* We used to try to bind a reference to a temporary here, but that
1736 is now handled after the recursive call to this function at the end
1737 of reference_binding. */
1738 return conv;
1739 }
1740
1741 return NULL;
1742 }
1743
1744 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1745 functions. ARGS will not be changed until a single candidate is
1746 selected. */
1747
1748 static struct z_candidate *
1749 add_candidate (struct z_candidate **candidates,
1750 tree fn, tree first_arg, const VEC(tree,gc) *args,
1751 size_t num_convs, conversion **convs,
1752 tree access_path, tree conversion_path,
1753 int viable, struct rejection_reason *reason)
1754 {
1755 struct z_candidate *cand = (struct z_candidate *)
1756 conversion_obstack_alloc (sizeof (struct z_candidate));
1757
1758 cand->fn = fn;
1759 cand->first_arg = first_arg;
1760 cand->args = args;
1761 cand->convs = convs;
1762 cand->num_convs = num_convs;
1763 cand->access_path = access_path;
1764 cand->conversion_path = conversion_path;
1765 cand->viable = viable;
1766 cand->reason = reason;
1767 cand->next = *candidates;
1768 *candidates = cand;
1769
1770 return cand;
1771 }
1772
1773 /* Return the number of remaining arguments in the parameter list
1774 beginning with ARG. */
1775
1776 static int
1777 remaining_arguments (tree arg)
1778 {
1779 int n;
1780
1781 for (n = 0; arg != NULL_TREE && arg != void_list_node;
1782 arg = TREE_CHAIN (arg))
1783 n++;
1784
1785 return n;
1786 }
1787
1788 /* Create an overload candidate for the function or method FN called
1789 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1790 FLAGS is passed on to implicit_conversion.
1791
1792 This does not change ARGS.
1793
1794 CTYPE, if non-NULL, is the type we want to pretend this function
1795 comes from for purposes of overload resolution. */
1796
1797 static struct z_candidate *
1798 add_function_candidate (struct z_candidate **candidates,
1799 tree fn, tree ctype, tree first_arg,
1800 const VEC(tree,gc) *args, tree access_path,
1801 tree conversion_path, int flags)
1802 {
1803 tree parmlist = TYPE_ARG_TYPES (TREE_TYPE (fn));
1804 int i, len;
1805 conversion **convs;
1806 tree parmnode;
1807 tree orig_first_arg = first_arg;
1808 int skip;
1809 int viable = 1;
1810 struct rejection_reason *reason = NULL;
1811
1812 /* At this point we should not see any functions which haven't been
1813 explicitly declared, except for friend functions which will have
1814 been found using argument dependent lookup. */
1815 gcc_assert (!DECL_ANTICIPATED (fn) || DECL_HIDDEN_FRIEND_P (fn));
1816
1817 /* The `this', `in_chrg' and VTT arguments to constructors are not
1818 considered in overload resolution. */
1819 if (DECL_CONSTRUCTOR_P (fn))
1820 {
1821 parmlist = skip_artificial_parms_for (fn, parmlist);
1822 skip = num_artificial_parms_for (fn);
1823 if (skip > 0 && first_arg != NULL_TREE)
1824 {
1825 --skip;
1826 first_arg = NULL_TREE;
1827 }
1828 }
1829 else
1830 skip = 0;
1831
1832 len = VEC_length (tree, args) - skip + (first_arg != NULL_TREE ? 1 : 0);
1833 convs = alloc_conversions (len);
1834
1835 /* 13.3.2 - Viable functions [over.match.viable]
1836 First, to be a viable function, a candidate function shall have enough
1837 parameters to agree in number with the arguments in the list.
1838
1839 We need to check this first; otherwise, checking the ICSes might cause
1840 us to produce an ill-formed template instantiation. */
1841
1842 parmnode = parmlist;
1843 for (i = 0; i < len; ++i)
1844 {
1845 if (parmnode == NULL_TREE || parmnode == void_list_node)
1846 break;
1847 parmnode = TREE_CHAIN (parmnode);
1848 }
1849
1850 if ((i < len && parmnode)
1851 || !sufficient_parms_p (parmnode))
1852 {
1853 int remaining = remaining_arguments (parmnode);
1854 viable = 0;
1855 reason = arity_rejection (first_arg, i + remaining, len);
1856 }
1857 /* When looking for a function from a subobject from an implicit
1858 copy/move constructor/operator=, don't consider anything that takes (a
1859 reference to) an unrelated type. See c++/44909 and core 1092. */
1860 else if (parmlist && (flags & LOOKUP_DEFAULTED))
1861 {
1862 if (DECL_CONSTRUCTOR_P (fn))
1863 i = 1;
1864 else if (DECL_ASSIGNMENT_OPERATOR_P (fn)
1865 && DECL_OVERLOADED_OPERATOR_P (fn) == NOP_EXPR)
1866 i = 2;
1867 else
1868 i = 0;
1869 if (i && len == i)
1870 {
1871 parmnode = chain_index (i-1, parmlist);
1872 if (!reference_related_p (non_reference (TREE_VALUE (parmnode)),
1873 ctype))
1874 viable = 0;
1875 }
1876
1877 /* This only applies at the top level. */
1878 flags &= ~LOOKUP_DEFAULTED;
1879 }
1880
1881 if (! viable)
1882 goto out;
1883
1884 /* Second, for F to be a viable function, there shall exist for each
1885 argument an implicit conversion sequence that converts that argument
1886 to the corresponding parameter of F. */
1887
1888 parmnode = parmlist;
1889
1890 for (i = 0; i < len; ++i)
1891 {
1892 tree arg, argtype, to_type;
1893 conversion *t;
1894 int is_this;
1895
1896 if (parmnode == void_list_node)
1897 break;
1898
1899 if (i == 0 && first_arg != NULL_TREE)
1900 arg = first_arg;
1901 else
1902 arg = VEC_index (tree, args,
1903 i + skip - (first_arg != NULL_TREE ? 1 : 0));
1904 argtype = lvalue_type (arg);
1905
1906 is_this = (i == 0 && DECL_NONSTATIC_MEMBER_FUNCTION_P (fn)
1907 && ! DECL_CONSTRUCTOR_P (fn));
1908
1909 if (parmnode)
1910 {
1911 tree parmtype = TREE_VALUE (parmnode);
1912 int lflags = flags;
1913
1914 parmnode = TREE_CHAIN (parmnode);
1915
1916 /* The type of the implicit object parameter ('this') for
1917 overload resolution is not always the same as for the
1918 function itself; conversion functions are considered to
1919 be members of the class being converted, and functions
1920 introduced by a using-declaration are considered to be
1921 members of the class that uses them.
1922
1923 Since build_over_call ignores the ICS for the `this'
1924 parameter, we can just change the parm type. */
1925 if (ctype && is_this)
1926 {
1927 parmtype = cp_build_qualified_type
1928 (ctype, cp_type_quals (TREE_TYPE (parmtype)));
1929 parmtype = build_pointer_type (parmtype);
1930 }
1931
1932 /* Core issue 899: When [copy-]initializing a temporary to be bound
1933 to the first parameter of a copy constructor (12.8) called with
1934 a single argument in the context of direct-initialization,
1935 explicit conversion functions are also considered.
1936
1937 So set LOOKUP_COPY_PARM to let reference_binding know that
1938 it's being called in that context. We generalize the above
1939 to handle move constructors and template constructors as well;
1940 the standardese should soon be updated similarly. */
1941 if (ctype && i == 0 && (len-skip == 1)
1942 && !(flags & LOOKUP_ONLYCONVERTING)
1943 && DECL_CONSTRUCTOR_P (fn)
1944 && parmtype != error_mark_node
1945 && (same_type_ignoring_top_level_qualifiers_p
1946 (non_reference (parmtype), ctype)))
1947 {
1948 lflags |= LOOKUP_COPY_PARM;
1949 /* We allow user-defined conversions within init-lists, but
1950 not for the copy constructor. */
1951 if (flags & LOOKUP_NO_COPY_CTOR_CONVERSION)
1952 lflags |= LOOKUP_NO_CONVERSION;
1953 }
1954 else
1955 lflags |= LOOKUP_ONLYCONVERTING;
1956
1957 t = implicit_conversion (parmtype, argtype, arg,
1958 /*c_cast_p=*/false, lflags);
1959 to_type = parmtype;
1960 }
1961 else
1962 {
1963 t = build_identity_conv (argtype, arg);
1964 t->ellipsis_p = true;
1965 to_type = argtype;
1966 }
1967
1968 if (t && is_this)
1969 t->this_p = true;
1970
1971 convs[i] = t;
1972 if (! t)
1973 {
1974 viable = 0;
1975 reason = arg_conversion_rejection (first_arg, i, argtype, to_type);
1976 break;
1977 }
1978
1979 if (t->bad_p)
1980 {
1981 viable = -1;
1982 reason = bad_arg_conversion_rejection (first_arg, i, argtype, to_type);
1983 }
1984 }
1985
1986 out:
1987 return add_candidate (candidates, fn, orig_first_arg, args, len, convs,
1988 access_path, conversion_path, viable, reason);
1989 }
1990
1991 /* Create an overload candidate for the conversion function FN which will
1992 be invoked for expression OBJ, producing a pointer-to-function which
1993 will in turn be called with the argument list FIRST_ARG/ARGLIST,
1994 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
1995 passed on to implicit_conversion.
1996
1997 Actually, we don't really care about FN; we care about the type it
1998 converts to. There may be multiple conversion functions that will
1999 convert to that type, and we rely on build_user_type_conversion_1 to
2000 choose the best one; so when we create our candidate, we record the type
2001 instead of the function. */
2002
2003 static struct z_candidate *
2004 add_conv_candidate (struct z_candidate **candidates, tree fn, tree obj,
2005 tree first_arg, const VEC(tree,gc) *arglist,
2006 tree access_path, tree conversion_path)
2007 {
2008 tree totype = TREE_TYPE (TREE_TYPE (fn));
2009 int i, len, viable, flags;
2010 tree parmlist, parmnode;
2011 conversion **convs;
2012 struct rejection_reason *reason;
2013
2014 for (parmlist = totype; TREE_CODE (parmlist) != FUNCTION_TYPE; )
2015 parmlist = TREE_TYPE (parmlist);
2016 parmlist = TYPE_ARG_TYPES (parmlist);
2017
2018 len = VEC_length (tree, arglist) + (first_arg != NULL_TREE ? 1 : 0) + 1;
2019 convs = alloc_conversions (len);
2020 parmnode = parmlist;
2021 viable = 1;
2022 flags = LOOKUP_IMPLICIT;
2023 reason = NULL;
2024
2025 /* Don't bother looking up the same type twice. */
2026 if (*candidates && (*candidates)->fn == totype)
2027 return NULL;
2028
2029 for (i = 0; i < len; ++i)
2030 {
2031 tree arg, argtype, convert_type = NULL_TREE;
2032 conversion *t;
2033
2034 if (i == 0)
2035 arg = obj;
2036 else if (i == 1 && first_arg != NULL_TREE)
2037 arg = first_arg;
2038 else
2039 arg = VEC_index (tree, arglist,
2040 i - (first_arg != NULL_TREE ? 1 : 0) - 1);
2041 argtype = lvalue_type (arg);
2042
2043 if (i == 0)
2044 {
2045 t = implicit_conversion (totype, argtype, arg, /*c_cast_p=*/false,
2046 flags);
2047 convert_type = totype;
2048 }
2049 else if (parmnode == void_list_node)
2050 break;
2051 else if (parmnode)
2052 {
2053 t = implicit_conversion (TREE_VALUE (parmnode), argtype, arg,
2054 /*c_cast_p=*/false, flags);
2055 convert_type = TREE_VALUE (parmnode);
2056 }
2057 else
2058 {
2059 t = build_identity_conv (argtype, arg);
2060 t->ellipsis_p = true;
2061 convert_type = argtype;
2062 }
2063
2064 convs[i] = t;
2065 if (! t)
2066 break;
2067
2068 if (t->bad_p)
2069 {
2070 viable = -1;
2071 reason = bad_arg_conversion_rejection (NULL_TREE, i, argtype, convert_type);
2072 }
2073
2074 if (i == 0)
2075 continue;
2076
2077 if (parmnode)
2078 parmnode = TREE_CHAIN (parmnode);
2079 }
2080
2081 if (i < len
2082 || ! sufficient_parms_p (parmnode))
2083 {
2084 int remaining = remaining_arguments (parmnode);
2085 viable = 0;
2086 reason = arity_rejection (NULL_TREE, i + remaining, len);
2087 }
2088
2089 return add_candidate (candidates, totype, first_arg, arglist, len, convs,
2090 access_path, conversion_path, viable, reason);
2091 }
2092
2093 static void
2094 build_builtin_candidate (struct z_candidate **candidates, tree fnname,
2095 tree type1, tree type2, tree *args, tree *argtypes,
2096 int flags)
2097 {
2098 conversion *t;
2099 conversion **convs;
2100 size_t num_convs;
2101 int viable = 1, i;
2102 tree types[2];
2103 struct rejection_reason *reason = NULL;
2104
2105 types[0] = type1;
2106 types[1] = type2;
2107
2108 num_convs = args[2] ? 3 : (args[1] ? 2 : 1);
2109 convs = alloc_conversions (num_convs);
2110
2111 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2112 conversion ops are allowed. We handle that here by just checking for
2113 boolean_type_node because other operators don't ask for it. COND_EXPR
2114 also does contextual conversion to bool for the first operand, but we
2115 handle that in build_conditional_expr, and type1 here is operand 2. */
2116 if (type1 != boolean_type_node)
2117 flags |= LOOKUP_ONLYCONVERTING;
2118
2119 for (i = 0; i < 2; ++i)
2120 {
2121 if (! args[i])
2122 break;
2123
2124 t = implicit_conversion (types[i], argtypes[i], args[i],
2125 /*c_cast_p=*/false, flags);
2126 if (! t)
2127 {
2128 viable = 0;
2129 /* We need something for printing the candidate. */
2130 t = build_identity_conv (types[i], NULL_TREE);
2131 reason = arg_conversion_rejection (NULL_TREE, i, argtypes[i], types[i]);
2132 }
2133 else if (t->bad_p)
2134 {
2135 viable = 0;
2136 reason = bad_arg_conversion_rejection (NULL_TREE, i, argtypes[i], types[i]);
2137 }
2138 convs[i] = t;
2139 }
2140
2141 /* For COND_EXPR we rearranged the arguments; undo that now. */
2142 if (args[2])
2143 {
2144 convs[2] = convs[1];
2145 convs[1] = convs[0];
2146 t = implicit_conversion (boolean_type_node, argtypes[2], args[2],
2147 /*c_cast_p=*/false, flags);
2148 if (t)
2149 convs[0] = t;
2150 else
2151 {
2152 viable = 0;
2153 reason = arg_conversion_rejection (NULL_TREE, 0, argtypes[2],
2154 boolean_type_node);
2155 }
2156 }
2157
2158 add_candidate (candidates, fnname, /*first_arg=*/NULL_TREE, /*args=*/NULL,
2159 num_convs, convs,
2160 /*access_path=*/NULL_TREE,
2161 /*conversion_path=*/NULL_TREE,
2162 viable, reason);
2163 }
2164
2165 static bool
2166 is_complete (tree t)
2167 {
2168 return COMPLETE_TYPE_P (complete_type (t));
2169 }
2170
2171 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2172
2173 static bool
2174 promoted_arithmetic_type_p (tree type)
2175 {
2176 /* [over.built]
2177
2178 In this section, the term promoted integral type is used to refer
2179 to those integral types which are preserved by integral promotion
2180 (including e.g. int and long but excluding e.g. char).
2181 Similarly, the term promoted arithmetic type refers to promoted
2182 integral types plus floating types. */
2183 return ((CP_INTEGRAL_TYPE_P (type)
2184 && same_type_p (type_promotes_to (type), type))
2185 || TREE_CODE (type) == REAL_TYPE);
2186 }
2187
2188 /* Create any builtin operator overload candidates for the operator in
2189 question given the converted operand types TYPE1 and TYPE2. The other
2190 args are passed through from add_builtin_candidates to
2191 build_builtin_candidate.
2192
2193 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2194 If CODE is requires candidates operands of the same type of the kind
2195 of which TYPE1 and TYPE2 are, we add both candidates
2196 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2197
2198 static void
2199 add_builtin_candidate (struct z_candidate **candidates, enum tree_code code,
2200 enum tree_code code2, tree fnname, tree type1,
2201 tree type2, tree *args, tree *argtypes, int flags)
2202 {
2203 switch (code)
2204 {
2205 case POSTINCREMENT_EXPR:
2206 case POSTDECREMENT_EXPR:
2207 args[1] = integer_zero_node;
2208 type2 = integer_type_node;
2209 break;
2210 default:
2211 break;
2212 }
2213
2214 switch (code)
2215 {
2216
2217 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2218 and VQ is either volatile or empty, there exist candidate operator
2219 functions of the form
2220 VQ T& operator++(VQ T&);
2221 T operator++(VQ T&, int);
2222 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2223 type other than bool, and VQ is either volatile or empty, there exist
2224 candidate operator functions of the form
2225 VQ T& operator--(VQ T&);
2226 T operator--(VQ T&, int);
2227 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2228 complete object type, and VQ is either volatile or empty, there exist
2229 candidate operator functions of the form
2230 T*VQ& operator++(T*VQ&);
2231 T*VQ& operator--(T*VQ&);
2232 T* operator++(T*VQ&, int);
2233 T* operator--(T*VQ&, int); */
2234
2235 case POSTDECREMENT_EXPR:
2236 case PREDECREMENT_EXPR:
2237 if (TREE_CODE (type1) == BOOLEAN_TYPE)
2238 return;
2239 case POSTINCREMENT_EXPR:
2240 case PREINCREMENT_EXPR:
2241 if (ARITHMETIC_TYPE_P (type1) || TYPE_PTROB_P (type1))
2242 {
2243 type1 = build_reference_type (type1);
2244 break;
2245 }
2246 return;
2247
2248 /* 7 For every cv-qualified or cv-unqualified object type T, there
2249 exist candidate operator functions of the form
2250
2251 T& operator*(T*);
2252
2253 8 For every function type T, there exist candidate operator functions of
2254 the form
2255 T& operator*(T*); */
2256
2257 case INDIRECT_REF:
2258 if (TREE_CODE (type1) == POINTER_TYPE
2259 && !uses_template_parms (TREE_TYPE (type1))
2260 && (TYPE_PTROB_P (type1)
2261 || TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE))
2262 break;
2263 return;
2264
2265 /* 9 For every type T, there exist candidate operator functions of the form
2266 T* operator+(T*);
2267
2268 10For every promoted arithmetic type T, there exist candidate operator
2269 functions of the form
2270 T operator+(T);
2271 T operator-(T); */
2272
2273 case UNARY_PLUS_EXPR: /* unary + */
2274 if (TREE_CODE (type1) == POINTER_TYPE)
2275 break;
2276 case NEGATE_EXPR:
2277 if (ARITHMETIC_TYPE_P (type1))
2278 break;
2279 return;
2280
2281 /* 11For every promoted integral type T, there exist candidate operator
2282 functions of the form
2283 T operator~(T); */
2284
2285 case BIT_NOT_EXPR:
2286 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1))
2287 break;
2288 return;
2289
2290 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2291 is the same type as C2 or is a derived class of C2, T is a complete
2292 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2293 there exist candidate operator functions of the form
2294 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2295 where CV12 is the union of CV1 and CV2. */
2296
2297 case MEMBER_REF:
2298 if (TREE_CODE (type1) == POINTER_TYPE
2299 && TYPE_PTR_TO_MEMBER_P (type2))
2300 {
2301 tree c1 = TREE_TYPE (type1);
2302 tree c2 = TYPE_PTRMEM_CLASS_TYPE (type2);
2303
2304 if (MAYBE_CLASS_TYPE_P (c1) && DERIVED_FROM_P (c2, c1)
2305 && (TYPE_PTRMEMFUNC_P (type2)
2306 || is_complete (TYPE_PTRMEM_POINTED_TO_TYPE (type2))))
2307 break;
2308 }
2309 return;
2310
2311 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2312 didate operator functions of the form
2313 LR operator*(L, R);
2314 LR operator/(L, R);
2315 LR operator+(L, R);
2316 LR operator-(L, R);
2317 bool operator<(L, R);
2318 bool operator>(L, R);
2319 bool operator<=(L, R);
2320 bool operator>=(L, R);
2321 bool operator==(L, R);
2322 bool operator!=(L, R);
2323 where LR is the result of the usual arithmetic conversions between
2324 types L and R.
2325
2326 14For every pair of types T and I, where T is a cv-qualified or cv-
2327 unqualified complete object type and I is a promoted integral type,
2328 there exist candidate operator functions of the form
2329 T* operator+(T*, I);
2330 T& operator[](T*, I);
2331 T* operator-(T*, I);
2332 T* operator+(I, T*);
2333 T& operator[](I, T*);
2334
2335 15For every T, where T is a pointer to complete object type, there exist
2336 candidate operator functions of the form112)
2337 ptrdiff_t operator-(T, T);
2338
2339 16For every pointer or enumeration type T, there exist candidate operator
2340 functions of the form
2341 bool operator<(T, T);
2342 bool operator>(T, T);
2343 bool operator<=(T, T);
2344 bool operator>=(T, T);
2345 bool operator==(T, T);
2346 bool operator!=(T, T);
2347
2348 17For every pointer to member type T, there exist candidate operator
2349 functions of the form
2350 bool operator==(T, T);
2351 bool operator!=(T, T); */
2352
2353 case MINUS_EXPR:
2354 if (TYPE_PTROB_P (type1) && TYPE_PTROB_P (type2))
2355 break;
2356 if (TYPE_PTROB_P (type1)
2357 && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2358 {
2359 type2 = ptrdiff_type_node;
2360 break;
2361 }
2362 case MULT_EXPR:
2363 case TRUNC_DIV_EXPR:
2364 if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
2365 break;
2366 return;
2367
2368 case EQ_EXPR:
2369 case NE_EXPR:
2370 if ((TYPE_PTRMEMFUNC_P (type1) && TYPE_PTRMEMFUNC_P (type2))
2371 || (TYPE_PTRMEM_P (type1) && TYPE_PTRMEM_P (type2)))
2372 break;
2373 if (TYPE_PTR_TO_MEMBER_P (type1) && null_ptr_cst_p (args[1]))
2374 {
2375 type2 = type1;
2376 break;
2377 }
2378 if (TYPE_PTR_TO_MEMBER_P (type2) && null_ptr_cst_p (args[0]))
2379 {
2380 type1 = type2;
2381 break;
2382 }
2383 /* Fall through. */
2384 case LT_EXPR:
2385 case GT_EXPR:
2386 case LE_EXPR:
2387 case GE_EXPR:
2388 case MAX_EXPR:
2389 case MIN_EXPR:
2390 if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
2391 break;
2392 if (TYPE_PTR_P (type1) && TYPE_PTR_P (type2))
2393 break;
2394 if (TREE_CODE (type1) == ENUMERAL_TYPE
2395 && TREE_CODE (type2) == ENUMERAL_TYPE)
2396 break;
2397 if (TYPE_PTR_P (type1)
2398 && null_ptr_cst_p (args[1])
2399 && !uses_template_parms (type1))
2400 {
2401 type2 = type1;
2402 break;
2403 }
2404 if (null_ptr_cst_p (args[0])
2405 && TYPE_PTR_P (type2)
2406 && !uses_template_parms (type2))
2407 {
2408 type1 = type2;
2409 break;
2410 }
2411 return;
2412
2413 case PLUS_EXPR:
2414 if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
2415 break;
2416 case ARRAY_REF:
2417 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && TYPE_PTROB_P (type2))
2418 {
2419 type1 = ptrdiff_type_node;
2420 break;
2421 }
2422 if (TYPE_PTROB_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2423 {
2424 type2 = ptrdiff_type_node;
2425 break;
2426 }
2427 return;
2428
2429 /* 18For every pair of promoted integral types L and R, there exist candi-
2430 date operator functions of the form
2431 LR operator%(L, R);
2432 LR operator&(L, R);
2433 LR operator^(L, R);
2434 LR operator|(L, R);
2435 L operator<<(L, R);
2436 L operator>>(L, R);
2437 where LR is the result of the usual arithmetic conversions between
2438 types L and R. */
2439
2440 case TRUNC_MOD_EXPR:
2441 case BIT_AND_EXPR:
2442 case BIT_IOR_EXPR:
2443 case BIT_XOR_EXPR:
2444 case LSHIFT_EXPR:
2445 case RSHIFT_EXPR:
2446 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2447 break;
2448 return;
2449
2450 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2451 type, VQ is either volatile or empty, and R is a promoted arithmetic
2452 type, there exist candidate operator functions of the form
2453 VQ L& operator=(VQ L&, R);
2454 VQ L& operator*=(VQ L&, R);
2455 VQ L& operator/=(VQ L&, R);
2456 VQ L& operator+=(VQ L&, R);
2457 VQ L& operator-=(VQ L&, R);
2458
2459 20For every pair T, VQ), where T is any type and VQ is either volatile
2460 or empty, there exist candidate operator functions of the form
2461 T*VQ& operator=(T*VQ&, T*);
2462
2463 21For every pair T, VQ), where T is a pointer to member type and VQ is
2464 either volatile or empty, there exist candidate operator functions of
2465 the form
2466 VQ T& operator=(VQ T&, T);
2467
2468 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2469 unqualified complete object type, VQ is either volatile or empty, and
2470 I is a promoted integral type, there exist candidate operator func-
2471 tions of the form
2472 T*VQ& operator+=(T*VQ&, I);
2473 T*VQ& operator-=(T*VQ&, I);
2474
2475 23For every triple L, VQ, R), where L is an integral or enumeration
2476 type, VQ is either volatile or empty, and R is a promoted integral
2477 type, there exist candidate operator functions of the form
2478
2479 VQ L& operator%=(VQ L&, R);
2480 VQ L& operator<<=(VQ L&, R);
2481 VQ L& operator>>=(VQ L&, R);
2482 VQ L& operator&=(VQ L&, R);
2483 VQ L& operator^=(VQ L&, R);
2484 VQ L& operator|=(VQ L&, R); */
2485
2486 case MODIFY_EXPR:
2487 switch (code2)
2488 {
2489 case PLUS_EXPR:
2490 case MINUS_EXPR:
2491 if (TYPE_PTROB_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2492 {
2493 type2 = ptrdiff_type_node;
2494 break;
2495 }
2496 case MULT_EXPR:
2497 case TRUNC_DIV_EXPR:
2498 if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
2499 break;
2500 return;
2501
2502 case TRUNC_MOD_EXPR:
2503 case BIT_AND_EXPR:
2504 case BIT_IOR_EXPR:
2505 case BIT_XOR_EXPR:
2506 case LSHIFT_EXPR:
2507 case RSHIFT_EXPR:
2508 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2509 break;
2510 return;
2511
2512 case NOP_EXPR:
2513 if (ARITHMETIC_TYPE_P (type1) && ARITHMETIC_TYPE_P (type2))
2514 break;
2515 if ((TYPE_PTRMEMFUNC_P (type1) && TYPE_PTRMEMFUNC_P (type2))
2516 || (TYPE_PTR_P (type1) && TYPE_PTR_P (type2))
2517 || (TYPE_PTRMEM_P (type1) && TYPE_PTRMEM_P (type2))
2518 || ((TYPE_PTRMEMFUNC_P (type1)
2519 || TREE_CODE (type1) == POINTER_TYPE)
2520 && null_ptr_cst_p (args[1])))
2521 {
2522 type2 = type1;
2523 break;
2524 }
2525 return;
2526
2527 default:
2528 gcc_unreachable ();
2529 }
2530 type1 = build_reference_type (type1);
2531 break;
2532
2533 case COND_EXPR:
2534 /* [over.built]
2535
2536 For every pair of promoted arithmetic types L and R, there
2537 exist candidate operator functions of the form
2538
2539 LR operator?(bool, L, R);
2540
2541 where LR is the result of the usual arithmetic conversions
2542 between types L and R.
2543
2544 For every type T, where T is a pointer or pointer-to-member
2545 type, there exist candidate operator functions of the form T
2546 operator?(bool, T, T); */
2547
2548 if (promoted_arithmetic_type_p (type1)
2549 && promoted_arithmetic_type_p (type2))
2550 /* That's OK. */
2551 break;
2552
2553 /* Otherwise, the types should be pointers. */
2554 if (!(TYPE_PTR_P (type1) || TYPE_PTR_TO_MEMBER_P (type1))
2555 || !(TYPE_PTR_P (type2) || TYPE_PTR_TO_MEMBER_P (type2)))
2556 return;
2557
2558 /* We don't check that the two types are the same; the logic
2559 below will actually create two candidates; one in which both
2560 parameter types are TYPE1, and one in which both parameter
2561 types are TYPE2. */
2562 break;
2563
2564 case REALPART_EXPR:
2565 case IMAGPART_EXPR:
2566 if (ARITHMETIC_TYPE_P (type1))
2567 break;
2568 return;
2569
2570 default:
2571 gcc_unreachable ();
2572 }
2573
2574 /* If we're dealing with two pointer types or two enumeral types,
2575 we need candidates for both of them. */
2576 if (type2 && !same_type_p (type1, type2)
2577 && TREE_CODE (type1) == TREE_CODE (type2)
2578 && (TREE_CODE (type1) == REFERENCE_TYPE
2579 || (TYPE_PTR_P (type1) && TYPE_PTR_P (type2))
2580 || (TYPE_PTRMEM_P (type1) && TYPE_PTRMEM_P (type2))
2581 || TYPE_PTRMEMFUNC_P (type1)
2582 || MAYBE_CLASS_TYPE_P (type1)
2583 || TREE_CODE (type1) == ENUMERAL_TYPE))
2584 {
2585 if (TYPE_PTR_P (type1) || TYPE_PTR_TO_MEMBER_P (type1))
2586 {
2587 tree cptype = composite_pointer_type (type1, type2,
2588 error_mark_node,
2589 error_mark_node,
2590 CPO_CONVERSION,
2591 tf_none);
2592 if (cptype != error_mark_node)
2593 {
2594 build_builtin_candidate
2595 (candidates, fnname, cptype, cptype, args, argtypes, flags);
2596 return;
2597 }
2598 }
2599
2600 build_builtin_candidate
2601 (candidates, fnname, type1, type1, args, argtypes, flags);
2602 build_builtin_candidate
2603 (candidates, fnname, type2, type2, args, argtypes, flags);
2604 return;
2605 }
2606
2607 build_builtin_candidate
2608 (candidates, fnname, type1, type2, args, argtypes, flags);
2609 }
2610
2611 tree
2612 type_decays_to (tree type)
2613 {
2614 if (TREE_CODE (type) == ARRAY_TYPE)
2615 return build_pointer_type (TREE_TYPE (type));
2616 if (TREE_CODE (type) == FUNCTION_TYPE)
2617 return build_pointer_type (type);
2618 return type;
2619 }
2620
2621 /* There are three conditions of builtin candidates:
2622
2623 1) bool-taking candidates. These are the same regardless of the input.
2624 2) pointer-pair taking candidates. These are generated for each type
2625 one of the input types converts to.
2626 3) arithmetic candidates. According to the standard, we should generate
2627 all of these, but I'm trying not to...
2628
2629 Here we generate a superset of the possible candidates for this particular
2630 case. That is a subset of the full set the standard defines, plus some
2631 other cases which the standard disallows. add_builtin_candidate will
2632 filter out the invalid set. */
2633
2634 static void
2635 add_builtin_candidates (struct z_candidate **candidates, enum tree_code code,
2636 enum tree_code code2, tree fnname, tree *args,
2637 int flags)
2638 {
2639 int ref1, i;
2640 int enum_p = 0;
2641 tree type, argtypes[3], t;
2642 /* TYPES[i] is the set of possible builtin-operator parameter types
2643 we will consider for the Ith argument. */
2644 VEC(tree,gc) *types[2];
2645 unsigned ix;
2646
2647 for (i = 0; i < 3; ++i)
2648 {
2649 if (args[i])
2650 argtypes[i] = unlowered_expr_type (args[i]);
2651 else
2652 argtypes[i] = NULL_TREE;
2653 }
2654
2655 switch (code)
2656 {
2657 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2658 and VQ is either volatile or empty, there exist candidate operator
2659 functions of the form
2660 VQ T& operator++(VQ T&); */
2661
2662 case POSTINCREMENT_EXPR:
2663 case PREINCREMENT_EXPR:
2664 case POSTDECREMENT_EXPR:
2665 case PREDECREMENT_EXPR:
2666 case MODIFY_EXPR:
2667 ref1 = 1;
2668 break;
2669
2670 /* 24There also exist candidate operator functions of the form
2671 bool operator!(bool);
2672 bool operator&&(bool, bool);
2673 bool operator||(bool, bool); */
2674
2675 case TRUTH_NOT_EXPR:
2676 build_builtin_candidate
2677 (candidates, fnname, boolean_type_node,
2678 NULL_TREE, args, argtypes, flags);
2679 return;
2680
2681 case TRUTH_ORIF_EXPR:
2682 case TRUTH_ANDIF_EXPR:
2683 build_builtin_candidate
2684 (candidates, fnname, boolean_type_node,
2685 boolean_type_node, args, argtypes, flags);
2686 return;
2687
2688 case ADDR_EXPR:
2689 case COMPOUND_EXPR:
2690 case COMPONENT_REF:
2691 return;
2692
2693 case COND_EXPR:
2694 case EQ_EXPR:
2695 case NE_EXPR:
2696 case LT_EXPR:
2697 case LE_EXPR:
2698 case GT_EXPR:
2699 case GE_EXPR:
2700 enum_p = 1;
2701 /* Fall through. */
2702
2703 default:
2704 ref1 = 0;
2705 }
2706
2707 types[0] = make_tree_vector ();
2708 types[1] = make_tree_vector ();
2709
2710 for (i = 0; i < 2; ++i)
2711 {
2712 if (! args[i])
2713 ;
2714 else if (MAYBE_CLASS_TYPE_P (argtypes[i]))
2715 {
2716 tree convs;
2717
2718 if (i == 0 && code == MODIFY_EXPR && code2 == NOP_EXPR)
2719 return;
2720
2721 convs = lookup_conversions (argtypes[i]);
2722
2723 if (code == COND_EXPR)
2724 {
2725 if (real_lvalue_p (args[i]))
2726 VEC_safe_push (tree, gc, types[i],
2727 build_reference_type (argtypes[i]));
2728
2729 VEC_safe_push (tree, gc, types[i],
2730 TYPE_MAIN_VARIANT (argtypes[i]));
2731 }
2732
2733 else if (! convs)
2734 return;
2735
2736 for (; convs; convs = TREE_CHAIN (convs))
2737 {
2738 type = TREE_TYPE (convs);
2739
2740 if (i == 0 && ref1
2741 && (TREE_CODE (type) != REFERENCE_TYPE
2742 || CP_TYPE_CONST_P (TREE_TYPE (type))))
2743 continue;
2744
2745 if (code == COND_EXPR && TREE_CODE (type) == REFERENCE_TYPE)
2746 VEC_safe_push (tree, gc, types[i], type);
2747
2748 type = non_reference (type);
2749 if (i != 0 || ! ref1)
2750 {
2751 type = cv_unqualified (type_decays_to (type));
2752 if (enum_p && TREE_CODE (type) == ENUMERAL_TYPE)
2753 VEC_safe_push (tree, gc, types[i], type);
2754 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type))
2755 type = type_promotes_to (type);
2756 }
2757
2758 if (! vec_member (type, types[i]))
2759 VEC_safe_push (tree, gc, types[i], type);
2760 }
2761 }
2762 else
2763 {
2764 if (code == COND_EXPR && real_lvalue_p (args[i]))
2765 VEC_safe_push (tree, gc, types[i],
2766 build_reference_type (argtypes[i]));
2767 type = non_reference (argtypes[i]);
2768 if (i != 0 || ! ref1)
2769 {
2770 type = cv_unqualified (type_decays_to (type));
2771 if (enum_p && UNSCOPED_ENUM_P (type))
2772 VEC_safe_push (tree, gc, types[i], type);
2773 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type))
2774 type = type_promotes_to (type);
2775 }
2776 VEC_safe_push (tree, gc, types[i], type);
2777 }
2778 }
2779
2780 /* Run through the possible parameter types of both arguments,
2781 creating candidates with those parameter types. */
2782 FOR_EACH_VEC_ELT_REVERSE (tree, types[0], ix, t)
2783 {
2784 unsigned jx;
2785 tree u;
2786
2787 if (!VEC_empty (tree, types[1]))
2788 FOR_EACH_VEC_ELT_REVERSE (tree, types[1], jx, u)
2789 add_builtin_candidate
2790 (candidates, code, code2, fnname, t,
2791 u, args, argtypes, flags);
2792 else
2793 add_builtin_candidate
2794 (candidates, code, code2, fnname, t,
2795 NULL_TREE, args, argtypes, flags);
2796 }
2797
2798 release_tree_vector (types[0]);
2799 release_tree_vector (types[1]);
2800 }
2801
2802
2803 /* If TMPL can be successfully instantiated as indicated by
2804 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2805
2806 TMPL is the template. EXPLICIT_TARGS are any explicit template
2807 arguments. ARGLIST is the arguments provided at the call-site.
2808 This does not change ARGLIST. The RETURN_TYPE is the desired type
2809 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2810 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2811 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2812
2813 static struct z_candidate*
2814 add_template_candidate_real (struct z_candidate **candidates, tree tmpl,
2815 tree ctype, tree explicit_targs, tree first_arg,
2816 const VEC(tree,gc) *arglist, tree return_type,
2817 tree access_path, tree conversion_path,
2818 int flags, tree obj, unification_kind_t strict)
2819 {
2820 int ntparms = DECL_NTPARMS (tmpl);
2821 tree targs = make_tree_vec (ntparms);
2822 unsigned int len = VEC_length (tree, arglist);
2823 unsigned int nargs = (first_arg == NULL_TREE ? 0 : 1) + len;
2824 unsigned int skip_without_in_chrg = 0;
2825 tree first_arg_without_in_chrg = first_arg;
2826 tree *args_without_in_chrg;
2827 unsigned int nargs_without_in_chrg;
2828 unsigned int ia, ix;
2829 tree arg;
2830 struct z_candidate *cand;
2831 int i;
2832 tree fn;
2833 struct rejection_reason *reason = NULL;
2834 int errs;
2835
2836 /* We don't do deduction on the in-charge parameter, the VTT
2837 parameter or 'this'. */
2838 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (tmpl))
2839 {
2840 if (first_arg_without_in_chrg != NULL_TREE)
2841 first_arg_without_in_chrg = NULL_TREE;
2842 else
2843 ++skip_without_in_chrg;
2844 }
2845
2846 if ((DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (tmpl)
2847 || DECL_BASE_CONSTRUCTOR_P (tmpl))
2848 && CLASSTYPE_VBASECLASSES (DECL_CONTEXT (tmpl)))
2849 {
2850 if (first_arg_without_in_chrg != NULL_TREE)
2851 first_arg_without_in_chrg = NULL_TREE;
2852 else
2853 ++skip_without_in_chrg;
2854 }
2855
2856 if (len < skip_without_in_chrg)
2857 return NULL;
2858
2859 nargs_without_in_chrg = ((first_arg_without_in_chrg != NULL_TREE ? 1 : 0)
2860 + (len - skip_without_in_chrg));
2861 args_without_in_chrg = XALLOCAVEC (tree, nargs_without_in_chrg);
2862 ia = 0;
2863 if (first_arg_without_in_chrg != NULL_TREE)
2864 {
2865 args_without_in_chrg[ia] = first_arg_without_in_chrg;
2866 ++ia;
2867 }
2868 for (ix = skip_without_in_chrg;
2869 VEC_iterate (tree, arglist, ix, arg);
2870 ++ix)
2871 {
2872 args_without_in_chrg[ia] = arg;
2873 ++ia;
2874 }
2875 gcc_assert (ia == nargs_without_in_chrg);
2876
2877 errs = errorcount+sorrycount;
2878 i = fn_type_unification (tmpl, explicit_targs, targs,
2879 args_without_in_chrg,
2880 nargs_without_in_chrg,
2881 return_type, strict, flags, false);
2882
2883 if (i != 0)
2884 {
2885 /* Don't repeat unification later if it already resulted in errors. */
2886 if (errorcount+sorrycount == errs)
2887 reason = template_unification_rejection (tmpl, explicit_targs,
2888 targs, args_without_in_chrg,
2889 nargs_without_in_chrg,
2890 return_type, strict, flags);
2891 else
2892 reason = template_unification_error_rejection ();
2893 goto fail;
2894 }
2895
2896 fn = instantiate_template (tmpl, targs, tf_none);
2897 if (fn == error_mark_node)
2898 {
2899 reason = template_instantiation_rejection (tmpl, targs);
2900 goto fail;
2901 }
2902
2903 /* In [class.copy]:
2904
2905 A member function template is never instantiated to perform the
2906 copy of a class object to an object of its class type.
2907
2908 It's a little unclear what this means; the standard explicitly
2909 does allow a template to be used to copy a class. For example,
2910 in:
2911
2912 struct A {
2913 A(A&);
2914 template <class T> A(const T&);
2915 };
2916 const A f ();
2917 void g () { A a (f ()); }
2918
2919 the member template will be used to make the copy. The section
2920 quoted above appears in the paragraph that forbids constructors
2921 whose only parameter is (a possibly cv-qualified variant of) the
2922 class type, and a logical interpretation is that the intent was
2923 to forbid the instantiation of member templates which would then
2924 have that form. */
2925 if (DECL_CONSTRUCTOR_P (fn) && nargs == 2)
2926 {
2927 tree arg_types = FUNCTION_FIRST_USER_PARMTYPE (fn);
2928 if (arg_types && same_type_p (TYPE_MAIN_VARIANT (TREE_VALUE (arg_types)),
2929 ctype))
2930 {
2931 reason = invalid_copy_with_fn_template_rejection ();
2932 goto fail;
2933 }
2934 }
2935
2936 if (obj != NULL_TREE)
2937 /* Aha, this is a conversion function. */
2938 cand = add_conv_candidate (candidates, fn, obj, first_arg, arglist,
2939 access_path, conversion_path);
2940 else
2941 cand = add_function_candidate (candidates, fn, ctype,
2942 first_arg, arglist, access_path,
2943 conversion_path, flags);
2944 if (DECL_TI_TEMPLATE (fn) != tmpl)
2945 /* This situation can occur if a member template of a template
2946 class is specialized. Then, instantiate_template might return
2947 an instantiation of the specialization, in which case the
2948 DECL_TI_TEMPLATE field will point at the original
2949 specialization. For example:
2950
2951 template <class T> struct S { template <class U> void f(U);
2952 template <> void f(int) {}; };
2953 S<double> sd;
2954 sd.f(3);
2955
2956 Here, TMPL will be template <class U> S<double>::f(U).
2957 And, instantiate template will give us the specialization
2958 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2959 for this will point at template <class T> template <> S<T>::f(int),
2960 so that we can find the definition. For the purposes of
2961 overload resolution, however, we want the original TMPL. */
2962 cand->template_decl = build_template_info (tmpl, targs);
2963 else
2964 cand->template_decl = DECL_TEMPLATE_INFO (fn);
2965 cand->explicit_targs = explicit_targs;
2966
2967 return cand;
2968 fail:
2969 return add_candidate (candidates, tmpl, first_arg, arglist, nargs, NULL,
2970 access_path, conversion_path, 0, reason);
2971 }
2972
2973
2974 static struct z_candidate *
2975 add_template_candidate (struct z_candidate **candidates, tree tmpl, tree ctype,
2976 tree explicit_targs, tree first_arg,
2977 const VEC(tree,gc) *arglist, tree return_type,
2978 tree access_path, tree conversion_path, int flags,
2979 unification_kind_t strict)
2980 {
2981 return
2982 add_template_candidate_real (candidates, tmpl, ctype,
2983 explicit_targs, first_arg, arglist,
2984 return_type, access_path, conversion_path,
2985 flags, NULL_TREE, strict);
2986 }
2987
2988
2989 static struct z_candidate *
2990 add_template_conv_candidate (struct z_candidate **candidates, tree tmpl,
2991 tree obj, tree first_arg,
2992 const VEC(tree,gc) *arglist,
2993 tree return_type, tree access_path,
2994 tree conversion_path)
2995 {
2996 return
2997 add_template_candidate_real (candidates, tmpl, NULL_TREE, NULL_TREE,
2998 first_arg, arglist, return_type, access_path,
2999 conversion_path, 0, obj, DEDUCE_CONV);
3000 }
3001
3002 /* The CANDS are the set of candidates that were considered for
3003 overload resolution. Return the set of viable candidates, or CANDS
3004 if none are viable. If any of the candidates were viable, set
3005 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3006 considered viable only if it is strictly viable. */
3007
3008 static struct z_candidate*
3009 splice_viable (struct z_candidate *cands,
3010 bool strict_p,
3011 bool *any_viable_p)
3012 {
3013 struct z_candidate *viable;
3014 struct z_candidate **last_viable;
3015 struct z_candidate **cand;
3016
3017 /* Be strict inside templates, since build_over_call won't actually
3018 do the conversions to get pedwarns. */
3019 if (processing_template_decl)
3020 strict_p = true;
3021
3022 viable = NULL;
3023 last_viable = &viable;
3024 *any_viable_p = false;
3025
3026 cand = &cands;
3027 while (*cand)
3028 {
3029 struct z_candidate *c = *cand;
3030 if (strict_p ? c->viable == 1 : c->viable)
3031 {
3032 *last_viable = c;
3033 *cand = c->next;
3034 c->next = NULL;
3035 last_viable = &c->next;
3036 *any_viable_p = true;
3037 }
3038 else
3039 cand = &c->next;
3040 }
3041
3042 return viable ? viable : cands;
3043 }
3044
3045 static bool
3046 any_strictly_viable (struct z_candidate *cands)
3047 {
3048 for (; cands; cands = cands->next)
3049 if (cands->viable == 1)
3050 return true;
3051 return false;
3052 }
3053
3054 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3055 words, it is about to become the "this" pointer for a member
3056 function call. Take the address of the object. */
3057
3058 static tree
3059 build_this (tree obj)
3060 {
3061 /* In a template, we are only concerned about the type of the
3062 expression, so we can take a shortcut. */
3063 if (processing_template_decl)
3064 return build_address (obj);
3065
3066 return cp_build_addr_expr (obj, tf_warning_or_error);
3067 }
3068
3069 /* Returns true iff functions are equivalent. Equivalent functions are
3070 not '==' only if one is a function-local extern function or if
3071 both are extern "C". */
3072
3073 static inline int
3074 equal_functions (tree fn1, tree fn2)
3075 {
3076 if (TREE_CODE (fn1) != TREE_CODE (fn2))
3077 return 0;
3078 if (TREE_CODE (fn1) == TEMPLATE_DECL)
3079 return fn1 == fn2;
3080 if (DECL_LOCAL_FUNCTION_P (fn1) || DECL_LOCAL_FUNCTION_P (fn2)
3081 || DECL_EXTERN_C_FUNCTION_P (fn1))
3082 return decls_match (fn1, fn2);
3083 return fn1 == fn2;
3084 }
3085
3086 /* Print information about a candidate being rejected due to INFO. */
3087
3088 static void
3089 print_conversion_rejection (location_t loc, struct conversion_info *info)
3090 {
3091 if (info->n_arg == -1)
3092 /* Conversion of implicit `this' argument failed. */
3093 inform (loc, " no known conversion for implicit "
3094 "%<this%> parameter from %qT to %qT",
3095 info->from_type, info->to_type);
3096 else
3097 inform (loc, " no known conversion for argument %d from %qT to %qT",
3098 info->n_arg+1, info->from_type, info->to_type);
3099 }
3100
3101 /* Print information about a candidate with WANT parameters and we found
3102 HAVE. */
3103
3104 static void
3105 print_arity_information (location_t loc, unsigned int have, unsigned int want)
3106 {
3107 inform_n (loc, want,
3108 " candidate expects %d argument, %d provided",
3109 " candidate expects %d arguments, %d provided",
3110 want, have);
3111 }
3112
3113 /* Print information about one overload candidate CANDIDATE. MSGSTR
3114 is the text to print before the candidate itself.
3115
3116 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3117 to have been run through gettext by the caller. This wart makes
3118 life simpler in print_z_candidates and for the translators. */
3119
3120 static void
3121 print_z_candidate (const char *msgstr, struct z_candidate *candidate)
3122 {
3123 const char *msg = (msgstr == NULL
3124 ? ""
3125 : ACONCAT ((msgstr, " ", NULL)));
3126 location_t loc = location_of (candidate->fn);
3127
3128 if (TREE_CODE (candidate->fn) == IDENTIFIER_NODE)
3129 {
3130 if (candidate->num_convs == 3)
3131 inform (input_location, "%s%D(%T, %T, %T) <built-in>", msg, candidate->fn,
3132 candidate->convs[0]->type,
3133 candidate->convs[1]->type,
3134 candidate->convs[2]->type);
3135 else if (candidate->num_convs == 2)
3136 inform (input_location, "%s%D(%T, %T) <built-in>", msg, candidate->fn,
3137 candidate->convs[0]->type,
3138 candidate->convs[1]->type);
3139 else
3140 inform (input_location, "%s%D(%T) <built-in>", msg, candidate->fn,
3141 candidate->convs[0]->type);
3142 }
3143 else if (TYPE_P (candidate->fn))
3144 inform (input_location, "%s%T <conversion>", msg, candidate->fn);
3145 else if (candidate->viable == -1)
3146 inform (loc, "%s%#D <near match>", msg, candidate->fn);
3147 else if (DECL_DELETED_FN (STRIP_TEMPLATE (candidate->fn)))
3148 inform (loc, "%s%#D <deleted>", msg, candidate->fn);
3149 else
3150 inform (loc, "%s%#D", msg, candidate->fn);
3151 /* Give the user some information about why this candidate failed. */
3152 if (candidate->reason != NULL)
3153 {
3154 struct rejection_reason *r = candidate->reason;
3155
3156 switch (r->code)
3157 {
3158 case rr_arity:
3159 print_arity_information (loc, r->u.arity.actual,
3160 r->u.arity.expected);
3161 break;
3162 case rr_arg_conversion:
3163 print_conversion_rejection (loc, &r->u.conversion);
3164 break;
3165 case rr_bad_arg_conversion:
3166 print_conversion_rejection (loc, &r->u.bad_conversion);
3167 break;
3168 case rr_explicit_conversion:
3169 inform (loc, " return type %qT of explicit conversion function "
3170 "cannot be converted to %qT with a qualification "
3171 "conversion", r->u.conversion.from_type,
3172 r->u.conversion.to_type);
3173 break;
3174 case rr_template_conversion:
3175 inform (loc, " conversion from return type %qT of template "
3176 "conversion function specialization to %qT is not an "
3177 "exact match", r->u.conversion.from_type,
3178 r->u.conversion.to_type);
3179 break;
3180 case rr_template_unification:
3181 /* We use template_unification_error_rejection if unification caused
3182 actual non-SFINAE errors, in which case we don't need to repeat
3183 them here. */
3184 if (r->u.template_unification.tmpl == NULL_TREE)
3185 {
3186 inform (loc, " substitution of deduced template arguments "
3187 "resulted in errors seen above");
3188 break;
3189 }
3190 /* Re-run template unification with diagnostics. */
3191 inform (loc, " template argument deduction/substitution failed:");
3192 fn_type_unification (r->u.template_unification.tmpl,
3193 r->u.template_unification.explicit_targs,
3194 r->u.template_unification.targs,
3195 r->u.template_unification.args,
3196 r->u.template_unification.nargs,
3197 r->u.template_unification.return_type,
3198 r->u.template_unification.strict,
3199 r->u.template_unification.flags,
3200 true);
3201 break;
3202 case rr_template_instantiation:
3203 /* Re-run template instantiation with diagnostics. */
3204 instantiate_template (r->u.template_instantiation.tmpl,
3205 r->u.template_instantiation.targs,
3206 tf_warning_or_error);
3207 break;
3208 case rr_invalid_copy:
3209 inform (loc,
3210 " a constructor taking a single argument of its own "
3211 "class type is invalid");
3212 break;
3213 case rr_none:
3214 default:
3215 /* This candidate didn't have any issues or we failed to
3216 handle a particular code. Either way... */
3217 gcc_unreachable ();
3218 }
3219 }
3220 }
3221
3222 static void
3223 print_z_candidates (location_t loc, struct z_candidate *candidates)
3224 {
3225 struct z_candidate *cand1;
3226 struct z_candidate **cand2;
3227 int n_candidates;
3228
3229 if (!candidates)
3230 return;
3231
3232 /* Remove non-viable deleted candidates. */
3233 cand1 = candidates;
3234 for (cand2 = &cand1; *cand2; )
3235 {
3236 if (TREE_CODE ((*cand2)->fn) == FUNCTION_DECL
3237 && !(*cand2)->viable
3238 && DECL_DELETED_FN ((*cand2)->fn))
3239 *cand2 = (*cand2)->next;
3240 else
3241 cand2 = &(*cand2)->next;
3242 }
3243 /* ...if there are any non-deleted ones. */
3244 if (cand1)
3245 candidates = cand1;
3246
3247 /* There may be duplicates in the set of candidates. We put off
3248 checking this condition as long as possible, since we have no way
3249 to eliminate duplicates from a set of functions in less than n^2
3250 time. Now we are about to emit an error message, so it is more
3251 permissible to go slowly. */
3252 for (cand1 = candidates; cand1; cand1 = cand1->next)
3253 {
3254 tree fn = cand1->fn;
3255 /* Skip builtin candidates and conversion functions. */
3256 if (!DECL_P (fn))
3257 continue;
3258 cand2 = &cand1->next;
3259 while (*cand2)
3260 {
3261 if (DECL_P ((*cand2)->fn)
3262 && equal_functions (fn, (*cand2)->fn))
3263 *cand2 = (*cand2)->next;
3264 else
3265 cand2 = &(*cand2)->next;
3266 }
3267 }
3268
3269 for (n_candidates = 0, cand1 = candidates; cand1; cand1 = cand1->next)
3270 n_candidates++;
3271
3272 inform_n (loc, n_candidates, "candidate is:", "candidates are:");
3273 for (; candidates; candidates = candidates->next)
3274 print_z_candidate (NULL, candidates);
3275 }
3276
3277 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3278 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3279 the result of the conversion function to convert it to the final
3280 desired type. Merge the two sequences into a single sequence,
3281 and return the merged sequence. */
3282
3283 static conversion *
3284 merge_conversion_sequences (conversion *user_seq, conversion *std_seq)
3285 {
3286 conversion **t;
3287 bool bad = user_seq->bad_p;
3288
3289 gcc_assert (user_seq->kind == ck_user);
3290
3291 /* Find the end of the second conversion sequence. */
3292 for (t = &std_seq; (*t)->kind != ck_identity; t = &((*t)->u.next))
3293 {
3294 /* The entire sequence is a user-conversion sequence. */
3295 (*t)->user_conv_p = true;
3296 if (bad)
3297 (*t)->bad_p = true;
3298 }
3299
3300 /* Replace the identity conversion with the user conversion
3301 sequence. */
3302 *t = user_seq;
3303
3304 return std_seq;
3305 }
3306
3307 /* Handle overload resolution for initializing an object of class type from
3308 an initializer list. First we look for a suitable constructor that
3309 takes a std::initializer_list; if we don't find one, we then look for a
3310 non-list constructor.
3311
3312 Parameters are as for add_candidates, except that the arguments are in
3313 the form of a CONSTRUCTOR (the initializer list) rather than a VEC, and
3314 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3315
3316 static void
3317 add_list_candidates (tree fns, tree first_arg,
3318 tree init_list, tree totype,
3319 tree explicit_targs, bool template_only,
3320 tree conversion_path, tree access_path,
3321 int flags,
3322 struct z_candidate **candidates)
3323 {
3324 VEC(tree,gc) *args;
3325
3326 gcc_assert (*candidates == NULL);
3327
3328 /* For list-initialization we consider explicit constructors, but
3329 give an error if one is selected. */
3330 flags &= ~LOOKUP_ONLYCONVERTING;
3331 /* And we don't allow narrowing conversions. We also use this flag to
3332 avoid the copy constructor call for copy-list-initialization. */
3333 flags |= LOOKUP_NO_NARROWING;
3334
3335 /* Always use the default constructor if the list is empty (DR 990). */
3336 if (CONSTRUCTOR_NELTS (init_list) == 0
3337 && TYPE_HAS_DEFAULT_CONSTRUCTOR (totype))
3338 ;
3339 /* If the class has a list ctor, try passing the list as a single
3340 argument first, but only consider list ctors. */
3341 else if (TYPE_HAS_LIST_CTOR (totype))
3342 {
3343 flags |= LOOKUP_LIST_ONLY;
3344 args = make_tree_vector_single (init_list);
3345 add_candidates (fns, first_arg, args, NULL_TREE,
3346 explicit_targs, template_only, conversion_path,
3347 access_path, flags, candidates);
3348 if (any_strictly_viable (*candidates))
3349 return;
3350 }
3351
3352 args = ctor_to_vec (init_list);
3353
3354 /* We aren't looking for list-ctors anymore. */
3355 flags &= ~LOOKUP_LIST_ONLY;
3356 /* We allow more user-defined conversions within an init-list. */
3357 flags &= ~LOOKUP_NO_CONVERSION;
3358 /* But not for the copy ctor. */
3359 flags |= LOOKUP_NO_COPY_CTOR_CONVERSION;
3360
3361 add_candidates (fns, first_arg, args, NULL_TREE,
3362 explicit_targs, template_only, conversion_path,
3363 access_path, flags, candidates);
3364 }
3365
3366 /* Returns the best overload candidate to perform the requested
3367 conversion. This function is used for three the overloading situations
3368 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3369 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3370 per [dcl.init.ref], so we ignore temporary bindings. */
3371
3372 static struct z_candidate *
3373 build_user_type_conversion_1 (tree totype, tree expr, int flags)
3374 {
3375 struct z_candidate *candidates, *cand;
3376 tree fromtype = TREE_TYPE (expr);
3377 tree ctors = NULL_TREE;
3378 tree conv_fns = NULL_TREE;
3379 conversion *conv = NULL;
3380 tree first_arg = NULL_TREE;
3381 VEC(tree,gc) *args = NULL;
3382 bool any_viable_p;
3383 int convflags;
3384
3385 /* We represent conversion within a hierarchy using RVALUE_CONV and
3386 BASE_CONV, as specified by [over.best.ics]; these become plain
3387 constructor calls, as specified in [dcl.init]. */
3388 gcc_assert (!MAYBE_CLASS_TYPE_P (fromtype) || !MAYBE_CLASS_TYPE_P (totype)
3389 || !DERIVED_FROM_P (totype, fromtype));
3390
3391 if (MAYBE_CLASS_TYPE_P (totype))
3392 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3393 creating a garbage BASELINK; constructors can't be inherited. */
3394 ctors = lookup_fnfields_slot (totype, complete_ctor_identifier);
3395
3396 if (MAYBE_CLASS_TYPE_P (fromtype))
3397 {
3398 tree to_nonref = non_reference (totype);
3399 if (same_type_ignoring_top_level_qualifiers_p (to_nonref, fromtype) ||
3400 (CLASS_TYPE_P (to_nonref) && CLASS_TYPE_P (fromtype)
3401 && DERIVED_FROM_P (to_nonref, fromtype)))
3402 {
3403 /* [class.conv.fct] A conversion function is never used to
3404 convert a (possibly cv-qualified) object to the (possibly
3405 cv-qualified) same object type (or a reference to it), to a
3406 (possibly cv-qualified) base class of that type (or a
3407 reference to it)... */
3408 }
3409 else
3410 conv_fns = lookup_conversions (fromtype);
3411 }
3412
3413 candidates = 0;
3414 flags |= LOOKUP_NO_CONVERSION;
3415 if (BRACE_ENCLOSED_INITIALIZER_P (expr))
3416 flags |= LOOKUP_NO_NARROWING;
3417
3418 /* It's OK to bind a temporary for converting constructor arguments, but
3419 not in converting the return value of a conversion operator. */
3420 convflags = ((flags & LOOKUP_NO_TEMP_BIND) | LOOKUP_NO_CONVERSION);
3421 flags &= ~LOOKUP_NO_TEMP_BIND;
3422
3423 if (ctors)
3424 {
3425 int ctorflags = flags;
3426
3427 first_arg = build_int_cst (build_pointer_type (totype), 0);
3428
3429 /* We should never try to call the abstract or base constructor
3430 from here. */
3431 gcc_assert (!DECL_HAS_IN_CHARGE_PARM_P (OVL_CURRENT (ctors))
3432 && !DECL_HAS_VTT_PARM_P (OVL_CURRENT (ctors)));
3433
3434 if (BRACE_ENCLOSED_INITIALIZER_P (expr))
3435 {
3436 /* List-initialization. */
3437 add_list_candidates (ctors, first_arg, expr, totype, NULL_TREE,
3438 false, TYPE_BINFO (totype), TYPE_BINFO (totype),
3439 ctorflags, &candidates);
3440 }
3441 else
3442 {
3443 args = make_tree_vector_single (expr);
3444 add_candidates (ctors, first_arg, args, NULL_TREE, NULL_TREE, false,
3445 TYPE_BINFO (totype), TYPE_BINFO (totype),
3446 ctorflags, &candidates);
3447 }
3448
3449 for (cand = candidates; cand; cand = cand->next)
3450 {
3451 cand->second_conv = build_identity_conv (totype, NULL_TREE);
3452
3453 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3454 set, then this is copy-initialization. In that case, "The
3455 result of the call is then used to direct-initialize the
3456 object that is the destination of the copy-initialization."
3457 [dcl.init]
3458
3459 We represent this in the conversion sequence with an
3460 rvalue conversion, which means a constructor call. */
3461 if (TREE_CODE (totype) != REFERENCE_TYPE
3462 && !(convflags & LOOKUP_NO_TEMP_BIND))
3463 cand->second_conv
3464 = build_conv (ck_rvalue, totype, cand->second_conv);
3465 }
3466 }
3467
3468 if (conv_fns)
3469 first_arg = build_this (expr);
3470
3471 for (; conv_fns; conv_fns = TREE_CHAIN (conv_fns))
3472 {
3473 tree conversion_path = TREE_PURPOSE (conv_fns);
3474 struct z_candidate *old_candidates;
3475
3476 /* If we are called to convert to a reference type, we are trying to
3477 find a direct binding, so don't even consider temporaries. If
3478 we don't find a direct binding, the caller will try again to
3479 look for a temporary binding. */
3480 if (TREE_CODE (totype) == REFERENCE_TYPE)
3481 convflags |= LOOKUP_NO_TEMP_BIND;
3482
3483 old_candidates = candidates;
3484 add_candidates (TREE_VALUE (conv_fns), first_arg, NULL, totype,
3485 NULL_TREE, false,
3486 conversion_path, TYPE_BINFO (fromtype),
3487 flags, &candidates);
3488
3489 for (cand = candidates; cand != old_candidates; cand = cand->next)
3490 {
3491 tree rettype = TREE_TYPE (TREE_TYPE (cand->fn));
3492 conversion *ics
3493 = implicit_conversion (totype,
3494 rettype,
3495 0,
3496 /*c_cast_p=*/false, convflags);
3497
3498 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3499 copy-initialization. In that case, "The result of the
3500 call is then used to direct-initialize the object that is
3501 the destination of the copy-initialization." [dcl.init]
3502
3503 We represent this in the conversion sequence with an
3504 rvalue conversion, which means a constructor call. But
3505 don't add a second rvalue conversion if there's already
3506 one there. Which there really shouldn't be, but it's
3507 harmless since we'd add it here anyway. */
3508 if (ics && MAYBE_CLASS_TYPE_P (totype) && ics->kind != ck_rvalue
3509 && !(convflags & LOOKUP_NO_TEMP_BIND))
3510 ics = build_conv (ck_rvalue, totype, ics);
3511
3512 cand->second_conv = ics;
3513
3514 if (!ics)
3515 {
3516 cand->viable = 0;
3517 cand->reason = arg_conversion_rejection (NULL_TREE, -1,
3518 rettype, totype);
3519 }
3520 else if (DECL_NONCONVERTING_P (cand->fn)
3521 && ics->rank > cr_exact)
3522 {
3523 /* 13.3.1.5: For direct-initialization, those explicit
3524 conversion functions that are not hidden within S and
3525 yield type T or a type that can be converted to type T
3526 with a qualification conversion (4.4) are also candidate
3527 functions. */
3528 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3529 I've raised this issue with the committee. --jason 9/2011 */
3530 cand->viable = -1;
3531 cand->reason = explicit_conversion_rejection (rettype, totype);
3532 }
3533 else if (cand->viable == 1 && ics->bad_p)
3534 {
3535 cand->viable = -1;
3536 cand->reason
3537 = bad_arg_conversion_rejection (NULL_TREE, -1,
3538 rettype, totype);
3539 }
3540 else if (primary_template_instantiation_p (cand->fn)
3541 && ics->rank > cr_exact)
3542 {
3543 /* 13.3.3.1.2: If the user-defined conversion is specified by
3544 a specialization of a conversion function template, the
3545 second standard conversion sequence shall have exact match
3546 rank. */
3547 cand->viable = -1;
3548 cand->reason = template_conversion_rejection (rettype, totype);
3549 }
3550 }
3551 }
3552
3553 candidates = splice_viable (candidates, pedantic, &any_viable_p);
3554 if (!any_viable_p)
3555 {
3556 if (args)
3557 release_tree_vector (args);
3558 return NULL;
3559 }
3560
3561 cand = tourney (candidates);
3562 if (cand == 0)
3563 {
3564 if (flags & LOOKUP_COMPLAIN)
3565 {
3566 error ("conversion from %qT to %qT is ambiguous",
3567 fromtype, totype);
3568 print_z_candidates (location_of (expr), candidates);
3569 }
3570
3571 cand = candidates; /* any one will do */
3572 cand->second_conv = build_ambiguous_conv (totype, expr);
3573 cand->second_conv->user_conv_p = true;
3574 if (!any_strictly_viable (candidates))
3575 cand->second_conv->bad_p = true;
3576 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3577 ambiguous conversion is no worse than another user-defined
3578 conversion. */
3579
3580 return cand;
3581 }
3582
3583 /* Build the user conversion sequence. */
3584 conv = build_conv
3585 (ck_user,
3586 (DECL_CONSTRUCTOR_P (cand->fn)
3587 ? totype : non_reference (TREE_TYPE (TREE_TYPE (cand->fn)))),
3588 build_identity_conv (TREE_TYPE (expr), expr));
3589 conv->cand = cand;
3590 if (cand->viable == -1)
3591 conv->bad_p = true;
3592
3593 /* Remember that this was a list-initialization. */
3594 if (flags & LOOKUP_NO_NARROWING)
3595 conv->check_narrowing = true;
3596
3597 /* Combine it with the second conversion sequence. */
3598 cand->second_conv = merge_conversion_sequences (conv,
3599 cand->second_conv);
3600
3601 return cand;
3602 }
3603
3604 /* Wrapper for above. */
3605
3606 tree
3607 build_user_type_conversion (tree totype, tree expr, int flags)
3608 {
3609 struct z_candidate *cand;
3610 tree ret;
3611
3612 bool subtime = timevar_cond_start (TV_OVERLOAD);
3613 cand = build_user_type_conversion_1 (totype, expr, flags);
3614
3615 if (cand)
3616 {
3617 if (cand->second_conv->kind == ck_ambig)
3618 ret = error_mark_node;
3619 else
3620 {
3621 expr = convert_like (cand->second_conv, expr, tf_warning_or_error);
3622 ret = convert_from_reference (expr);
3623 }
3624 }
3625 else
3626 ret = NULL_TREE;
3627
3628 timevar_cond_stop (TV_OVERLOAD, subtime);
3629 return ret;
3630 }
3631
3632 /* Subroutine of convert_nontype_argument.
3633
3634 EXPR is an argument for a template non-type parameter of integral or
3635 enumeration type. Do any necessary conversions (that are permitted for
3636 non-type arguments) to convert it to the parameter type.
3637
3638 If conversion is successful, returns the converted expression;
3639 otherwise, returns error_mark_node. */
3640
3641 tree
3642 build_integral_nontype_arg_conv (tree type, tree expr, tsubst_flags_t complain)
3643 {
3644 conversion *conv;
3645 void *p;
3646 tree t;
3647
3648 if (error_operand_p (expr))
3649 return error_mark_node;
3650
3651 gcc_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type));
3652
3653 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3654 p = conversion_obstack_alloc (0);
3655
3656 conv = implicit_conversion (type, TREE_TYPE (expr), expr,
3657 /*c_cast_p=*/false,
3658 LOOKUP_IMPLICIT);
3659
3660 /* for a non-type template-parameter of integral or
3661 enumeration type, integral promotions (4.5) and integral
3662 conversions (4.7) are applied. */
3663 /* It should be sufficient to check the outermost conversion step, since
3664 there are no qualification conversions to integer type. */
3665 if (conv)
3666 switch (conv->kind)
3667 {
3668 /* A conversion function is OK. If it isn't constexpr, we'll
3669 complain later that the argument isn't constant. */
3670 case ck_user:
3671 /* The lvalue-to-rvalue conversion is OK. */
3672 case ck_rvalue:
3673 case ck_identity:
3674 break;
3675
3676 case ck_std:
3677 t = conv->u.next->type;
3678 if (INTEGRAL_OR_ENUMERATION_TYPE_P (t))
3679 break;
3680
3681 if (complain & tf_error)
3682 error ("conversion from %qT to %qT not considered for "
3683 "non-type template argument", t, type);
3684 /* and fall through. */
3685
3686 default:
3687 conv = NULL;
3688 break;
3689 }
3690
3691 if (conv)
3692 expr = convert_like (conv, expr, complain);
3693 else
3694 expr = error_mark_node;
3695
3696 /* Free all the conversions we allocated. */
3697 obstack_free (&conversion_obstack, p);
3698
3699 return expr;
3700 }
3701
3702 /* Do any initial processing on the arguments to a function call. */
3703
3704 static VEC(tree,gc) *
3705 resolve_args (VEC(tree,gc) *args, tsubst_flags_t complain)
3706 {
3707 unsigned int ix;
3708 tree arg;
3709
3710 FOR_EACH_VEC_ELT (tree, args, ix, arg)
3711 {
3712 if (error_operand_p (arg))
3713 return NULL;
3714 else if (VOID_TYPE_P (TREE_TYPE (arg)))
3715 {
3716 if (complain & tf_error)
3717 error ("invalid use of void expression");
3718 return NULL;
3719 }
3720 else if (invalid_nonstatic_memfn_p (arg, tf_warning_or_error))
3721 return NULL;
3722 }
3723 return args;
3724 }
3725
3726 /* Perform overload resolution on FN, which is called with the ARGS.
3727
3728 Return the candidate function selected by overload resolution, or
3729 NULL if the event that overload resolution failed. In the case
3730 that overload resolution fails, *CANDIDATES will be the set of
3731 candidates considered, and ANY_VIABLE_P will be set to true or
3732 false to indicate whether or not any of the candidates were
3733 viable.
3734
3735 The ARGS should already have gone through RESOLVE_ARGS before this
3736 function is called. */
3737
3738 static struct z_candidate *
3739 perform_overload_resolution (tree fn,
3740 const VEC(tree,gc) *args,
3741 struct z_candidate **candidates,
3742 bool *any_viable_p)
3743 {
3744 struct z_candidate *cand;
3745 tree explicit_targs;
3746 int template_only;
3747
3748 bool subtime = timevar_cond_start (TV_OVERLOAD);
3749
3750 explicit_targs = NULL_TREE;
3751 template_only = 0;
3752
3753 *candidates = NULL;
3754 *any_viable_p = true;
3755
3756 /* Check FN. */
3757 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL
3758 || TREE_CODE (fn) == TEMPLATE_DECL
3759 || TREE_CODE (fn) == OVERLOAD
3760 || TREE_CODE (fn) == TEMPLATE_ID_EXPR);
3761
3762 if (TREE_CODE (fn) == TEMPLATE_ID_EXPR)
3763 {
3764 explicit_targs = TREE_OPERAND (fn, 1);
3765 fn = TREE_OPERAND (fn, 0);
3766 template_only = 1;
3767 }
3768
3769 /* Add the various candidate functions. */
3770 add_candidates (fn, NULL_TREE, args, NULL_TREE,
3771 explicit_targs, template_only,
3772 /*conversion_path=*/NULL_TREE,
3773 /*access_path=*/NULL_TREE,
3774 LOOKUP_NORMAL,
3775 candidates);
3776
3777 *candidates = splice_viable (*candidates, pedantic, any_viable_p);
3778 if (*any_viable_p)
3779 cand = tourney (*candidates);
3780 else
3781 cand = NULL;
3782
3783 timevar_cond_stop (TV_OVERLOAD, subtime);
3784 return cand;
3785 }
3786
3787 /* Print an error message about being unable to build a call to FN with
3788 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
3789 be located; CANDIDATES is a possibly empty list of such
3790 functions. */
3791
3792 static void
3793 print_error_for_call_failure (tree fn, VEC(tree,gc) *args, bool any_viable_p,
3794 struct z_candidate *candidates)
3795 {
3796 tree name = DECL_NAME (OVL_CURRENT (fn));
3797 location_t loc = location_of (name);
3798
3799 if (!any_viable_p)
3800 error_at (loc, "no matching function for call to %<%D(%A)%>",
3801 name, build_tree_list_vec (args));
3802 else
3803 error_at (loc, "call of overloaded %<%D(%A)%> is ambiguous",
3804 name, build_tree_list_vec (args));
3805 if (candidates)
3806 print_z_candidates (loc, candidates);
3807 }
3808
3809 /* Return an expression for a call to FN (a namespace-scope function,
3810 or a static member function) with the ARGS. This may change
3811 ARGS. */
3812
3813 tree
3814 build_new_function_call (tree fn, VEC(tree,gc) **args, bool koenig_p,
3815 tsubst_flags_t complain)
3816 {
3817 struct z_candidate *candidates, *cand;
3818 bool any_viable_p;
3819 void *p;
3820 tree result;
3821
3822 if (args != NULL && *args != NULL)
3823 {
3824 *args = resolve_args (*args, complain);
3825 if (*args == NULL)
3826 return error_mark_node;
3827 }
3828
3829 if (flag_tm)
3830 tm_malloc_replacement (fn);
3831
3832 /* If this function was found without using argument dependent
3833 lookup, then we want to ignore any undeclared friend
3834 functions. */
3835 if (!koenig_p)
3836 {
3837 tree orig_fn = fn;
3838
3839 fn = remove_hidden_names (fn);
3840 if (!fn)
3841 {
3842 if (complain & tf_error)
3843 print_error_for_call_failure (orig_fn, *args, false, NULL);
3844 return error_mark_node;
3845 }
3846 }
3847
3848 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3849 p = conversion_obstack_alloc (0);
3850
3851 cand = perform_overload_resolution (fn, *args, &candidates, &any_viable_p);
3852
3853 if (!cand)
3854 {
3855 if (complain & tf_error)
3856 {
3857 if (!any_viable_p && candidates && ! candidates->next
3858 && (TREE_CODE (candidates->fn) == FUNCTION_DECL))
3859 return cp_build_function_call_vec (candidates->fn, args, complain);
3860 if (TREE_CODE (fn) == TEMPLATE_ID_EXPR)
3861 fn = TREE_OPERAND (fn, 0);
3862 print_error_for_call_failure (fn, *args, any_viable_p, candidates);
3863 }
3864 result = error_mark_node;
3865 }
3866 else
3867 {
3868 int flags = LOOKUP_NORMAL;
3869 /* If fn is template_id_expr, the call has explicit template arguments
3870 (e.g. func<int>(5)), communicate this info to build_over_call
3871 through flags so that later we can use it to decide whether to warn
3872 about peculiar null pointer conversion. */
3873 if (TREE_CODE (fn) == TEMPLATE_ID_EXPR)
3874 flags |= LOOKUP_EXPLICIT_TMPL_ARGS;
3875 result = build_over_call (cand, flags, complain);
3876 }
3877
3878 /* Free all the conversions we allocated. */
3879 obstack_free (&conversion_obstack, p);
3880
3881 return result;
3882 }
3883
3884 /* Build a call to a global operator new. FNNAME is the name of the
3885 operator (either "operator new" or "operator new[]") and ARGS are
3886 the arguments provided. This may change ARGS. *SIZE points to the
3887 total number of bytes required by the allocation, and is updated if
3888 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
3889 be used. If this function determines that no cookie should be
3890 used, after all, *COOKIE_SIZE is set to NULL_TREE. If FN is
3891 non-NULL, it will be set, upon return, to the allocation function
3892 called. */
3893
3894 tree
3895 build_operator_new_call (tree fnname, VEC(tree,gc) **args,
3896 tree *size, tree *cookie_size,
3897 tree *fn)
3898 {
3899 tree fns;
3900 struct z_candidate *candidates;
3901 struct z_candidate *cand;
3902 bool any_viable_p;
3903
3904 if (fn)
3905 *fn = NULL_TREE;
3906 VEC_safe_insert (tree, gc, *args, 0, *size);
3907 *args = resolve_args (*args, tf_warning_or_error);
3908 if (*args == NULL)
3909 return error_mark_node;
3910
3911 /* Based on:
3912
3913 [expr.new]
3914
3915 If this lookup fails to find the name, or if the allocated type
3916 is not a class type, the allocation function's name is looked
3917 up in the global scope.
3918
3919 we disregard block-scope declarations of "operator new". */
3920 fns = lookup_function_nonclass (fnname, *args, /*block_p=*/false);
3921
3922 /* Figure out what function is being called. */
3923 cand = perform_overload_resolution (fns, *args, &candidates, &any_viable_p);
3924
3925 /* If no suitable function could be found, issue an error message
3926 and give up. */
3927 if (!cand)
3928 {
3929 print_error_for_call_failure (fns, *args, any_viable_p, candidates);
3930 return error_mark_node;
3931 }
3932
3933 /* If a cookie is required, add some extra space. Whether
3934 or not a cookie is required cannot be determined until
3935 after we know which function was called. */
3936 if (*cookie_size)
3937 {
3938 bool use_cookie = true;
3939 if (!abi_version_at_least (2))
3940 {
3941 /* In G++ 3.2, the check was implemented incorrectly; it
3942 looked at the placement expression, rather than the
3943 type of the function. */
3944 if (VEC_length (tree, *args) == 2
3945 && same_type_p (TREE_TYPE (VEC_index (tree, *args, 1)),
3946 ptr_type_node))
3947 use_cookie = false;
3948 }
3949 else
3950 {
3951 tree arg_types;
3952
3953 arg_types = TYPE_ARG_TYPES (TREE_TYPE (cand->fn));
3954 /* Skip the size_t parameter. */
3955 arg_types = TREE_CHAIN (arg_types);
3956 /* Check the remaining parameters (if any). */
3957 if (arg_types
3958 && TREE_CHAIN (arg_types) == void_list_node
3959 && same_type_p (TREE_VALUE (arg_types),
3960 ptr_type_node))
3961 use_cookie = false;
3962 }
3963 /* If we need a cookie, adjust the number of bytes allocated. */
3964 if (use_cookie)
3965 {
3966 /* Update the total size. */
3967 *size = size_binop (PLUS_EXPR, *size, *cookie_size);
3968 /* Update the argument list to reflect the adjusted size. */
3969 VEC_replace (tree, *args, 0, *size);
3970 }
3971 else
3972 *cookie_size = NULL_TREE;
3973 }
3974
3975 /* Tell our caller which function we decided to call. */
3976 if (fn)
3977 *fn = cand->fn;
3978
3979 /* Build the CALL_EXPR. */
3980 return build_over_call (cand, LOOKUP_NORMAL, tf_warning_or_error);
3981 }
3982
3983 /* Build a new call to operator(). This may change ARGS. */
3984
3985 static tree
3986 build_op_call_1 (tree obj, VEC(tree,gc) **args, tsubst_flags_t complain)
3987 {
3988 struct z_candidate *candidates = 0, *cand;
3989 tree fns, convs, first_mem_arg = NULL_TREE;
3990 tree type = TREE_TYPE (obj);
3991 bool any_viable_p;
3992 tree result = NULL_TREE;
3993 void *p;
3994
3995 if (error_operand_p (obj))
3996 return error_mark_node;
3997
3998 obj = prep_operand (obj);
3999
4000 if (TYPE_PTRMEMFUNC_P (type))
4001 {
4002 if (complain & tf_error)
4003 /* It's no good looking for an overloaded operator() on a
4004 pointer-to-member-function. */
4005 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4006 return error_mark_node;
4007 }
4008
4009 if (TYPE_BINFO (type))
4010 {
4011 fns = lookup_fnfields (TYPE_BINFO (type), ansi_opname (CALL_EXPR), 1);
4012 if (fns == error_mark_node)
4013 return error_mark_node;
4014 }
4015 else
4016 fns = NULL_TREE;
4017
4018 if (args != NULL && *args != NULL)
4019 {
4020 *args = resolve_args (*args, complain);
4021 if (*args == NULL)
4022 return error_mark_node;
4023 }
4024
4025 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4026 p = conversion_obstack_alloc (0);
4027
4028 if (fns)
4029 {
4030 first_mem_arg = build_this (obj);
4031
4032 add_candidates (BASELINK_FUNCTIONS (fns),
4033 first_mem_arg, *args, NULL_TREE,
4034 NULL_TREE, false,
4035 BASELINK_BINFO (fns), BASELINK_ACCESS_BINFO (fns),
4036 LOOKUP_NORMAL, &candidates);
4037 }
4038
4039 convs = lookup_conversions (type);
4040
4041 for (; convs; convs = TREE_CHAIN (convs))
4042 {
4043 tree fns = TREE_VALUE (convs);
4044 tree totype = TREE_TYPE (convs);
4045
4046 if ((TREE_CODE (totype) == POINTER_TYPE
4047 && TREE_CODE (TREE_TYPE (totype)) == FUNCTION_TYPE)
4048 || (TREE_CODE (totype) == REFERENCE_TYPE
4049 && TREE_CODE (TREE_TYPE (totype)) == FUNCTION_TYPE)
4050 || (TREE_CODE (totype) == REFERENCE_TYPE
4051 && TREE_CODE (TREE_TYPE (totype)) == POINTER_TYPE
4052 && TREE_CODE (TREE_TYPE (TREE_TYPE (totype))) == FUNCTION_TYPE))
4053 for (; fns; fns = OVL_NEXT (fns))
4054 {
4055 tree fn = OVL_CURRENT (fns);
4056
4057 if (DECL_NONCONVERTING_P (fn))
4058 continue;
4059
4060 if (TREE_CODE (fn) == TEMPLATE_DECL)
4061 add_template_conv_candidate
4062 (&candidates, fn, obj, NULL_TREE, *args, totype,
4063 /*access_path=*/NULL_TREE,
4064 /*conversion_path=*/NULL_TREE);
4065 else
4066 add_conv_candidate (&candidates, fn, obj, NULL_TREE,
4067 *args, /*conversion_path=*/NULL_TREE,
4068 /*access_path=*/NULL_TREE);
4069 }
4070 }
4071
4072 candidates = splice_viable (candidates, pedantic, &any_viable_p);
4073 if (!any_viable_p)
4074 {
4075 if (complain & tf_error)
4076 {
4077 error ("no match for call to %<(%T) (%A)%>", TREE_TYPE (obj),
4078 build_tree_list_vec (*args));
4079 print_z_candidates (location_of (TREE_TYPE (obj)), candidates);
4080 }
4081 result = error_mark_node;
4082 }
4083 else
4084 {
4085 cand = tourney (candidates);
4086 if (cand == 0)
4087 {
4088 if (complain & tf_error)
4089 {
4090 error ("call of %<(%T) (%A)%> is ambiguous",
4091 TREE_TYPE (obj), build_tree_list_vec (*args));
4092 print_z_candidates (location_of (TREE_TYPE (obj)), candidates);
4093 }
4094 result = error_mark_node;
4095 }
4096 /* Since cand->fn will be a type, not a function, for a conversion
4097 function, we must be careful not to unconditionally look at
4098 DECL_NAME here. */
4099 else if (TREE_CODE (cand->fn) == FUNCTION_DECL
4100 && DECL_OVERLOADED_OPERATOR_P (cand->fn) == CALL_EXPR)
4101 result = build_over_call (cand, LOOKUP_NORMAL, complain);
4102 else
4103 {
4104 obj = convert_like_with_context (cand->convs[0], obj, cand->fn, -1,
4105 complain);
4106 obj = convert_from_reference (obj);
4107 result = cp_build_function_call_vec (obj, args, complain);
4108 }
4109 }
4110
4111 /* Free all the conversions we allocated. */
4112 obstack_free (&conversion_obstack, p);
4113
4114 return result;
4115 }
4116
4117 /* Wrapper for above. */
4118
4119 tree
4120 build_op_call (tree obj, VEC(tree,gc) **args, tsubst_flags_t complain)
4121 {
4122 tree ret;
4123 bool subtime = timevar_cond_start (TV_OVERLOAD);
4124 ret = build_op_call_1 (obj, args, complain);
4125 timevar_cond_stop (TV_OVERLOAD, subtime);
4126 return ret;
4127 }
4128
4129 static void
4130 op_error (enum tree_code code, enum tree_code code2,
4131 tree arg1, tree arg2, tree arg3, bool match)
4132 {
4133 const char *opname;
4134
4135 if (code == MODIFY_EXPR)
4136 opname = assignment_operator_name_info[code2].name;
4137 else
4138 opname = operator_name_info[code].name;
4139
4140 switch (code)
4141 {
4142 case COND_EXPR:
4143 if (match)
4144 error ("ambiguous overload for ternary %<operator?:%> "
4145 "in %<%E ? %E : %E%>", arg1, arg2, arg3);
4146 else
4147 error ("no match for ternary %<operator?:%> "
4148 "in %<%E ? %E : %E%>", arg1, arg2, arg3);
4149 break;
4150
4151 case POSTINCREMENT_EXPR:
4152 case POSTDECREMENT_EXPR:
4153 if (match)
4154 error ("ambiguous overload for %<operator%s%> in %<%E%s%>",
4155 opname, arg1, opname);
4156 else
4157 error ("no match for %<operator%s%> in %<%E%s%>",
4158 opname, arg1, opname);
4159 break;
4160
4161 case ARRAY_REF:
4162 if (match)
4163 error ("ambiguous overload for %<operator[]%> in %<%E[%E]%>",
4164 arg1, arg2);
4165 else
4166 error ("no match for %<operator[]%> in %<%E[%E]%>",
4167 arg1, arg2);
4168 break;
4169
4170 case REALPART_EXPR:
4171 case IMAGPART_EXPR:
4172 if (match)
4173 error ("ambiguous overload for %qs in %<%s %E%>",
4174 opname, opname, arg1);
4175 else
4176 error ("no match for %qs in %<%s %E%>",
4177 opname, opname, arg1);
4178 break;
4179
4180 default:
4181 if (arg2)
4182 if (match)
4183 error ("ambiguous overload for %<operator%s%> in %<%E %s %E%>",
4184 opname, arg1, opname, arg2);
4185 else
4186 error ("no match for %<operator%s%> in %<%E %s %E%>",
4187 opname, arg1, opname, arg2);
4188 else
4189 if (match)
4190 error ("ambiguous overload for %<operator%s%> in %<%s%E%>",
4191 opname, opname, arg1);
4192 else
4193 error ("no match for %<operator%s%> in %<%s%E%>",
4194 opname, opname, arg1);
4195 break;
4196 }
4197 }
4198
4199 /* Return the implicit conversion sequence that could be used to
4200 convert E1 to E2 in [expr.cond]. */
4201
4202 static conversion *
4203 conditional_conversion (tree e1, tree e2)
4204 {
4205 tree t1 = non_reference (TREE_TYPE (e1));
4206 tree t2 = non_reference (TREE_TYPE (e2));
4207 conversion *conv;
4208 bool good_base;
4209
4210 /* [expr.cond]
4211
4212 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4213 implicitly converted (clause _conv_) to the type "lvalue reference to
4214 T2", subject to the constraint that in the conversion the
4215 reference must bind directly (_dcl.init.ref_) to an lvalue. */
4216 if (real_lvalue_p (e2))
4217 {
4218 conv = implicit_conversion (build_reference_type (t2),
4219 t1,
4220 e1,
4221 /*c_cast_p=*/false,
4222 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4223 |LOOKUP_ONLYCONVERTING);
4224 if (conv)
4225 return conv;
4226 }
4227
4228 /* [expr.cond]
4229
4230 If E1 and E2 have class type, and the underlying class types are
4231 the same or one is a base class of the other: E1 can be converted
4232 to match E2 if the class of T2 is the same type as, or a base
4233 class of, the class of T1, and the cv-qualification of T2 is the
4234 same cv-qualification as, or a greater cv-qualification than, the
4235 cv-qualification of T1. If the conversion is applied, E1 is
4236 changed to an rvalue of type T2 that still refers to the original
4237 source class object (or the appropriate subobject thereof). */
4238 if (CLASS_TYPE_P (t1) && CLASS_TYPE_P (t2)
4239 && ((good_base = DERIVED_FROM_P (t2, t1)) || DERIVED_FROM_P (t1, t2)))
4240 {
4241 if (good_base && at_least_as_qualified_p (t2, t1))
4242 {
4243 conv = build_identity_conv (t1, e1);
4244 if (!same_type_p (TYPE_MAIN_VARIANT (t1),
4245 TYPE_MAIN_VARIANT (t2)))
4246 conv = build_conv (ck_base, t2, conv);
4247 else
4248 conv = build_conv (ck_rvalue, t2, conv);
4249 return conv;
4250 }
4251 else
4252 return NULL;
4253 }
4254 else
4255 /* [expr.cond]
4256
4257 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4258 converted to the type that expression E2 would have if E2 were
4259 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4260 return implicit_conversion (t2, t1, e1, /*c_cast_p=*/false,
4261 LOOKUP_IMPLICIT);
4262 }
4263
4264 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4265 arguments to the conditional expression. */
4266
4267 static tree
4268 build_conditional_expr_1 (tree arg1, tree arg2, tree arg3,
4269 tsubst_flags_t complain)
4270 {
4271 tree arg2_type;
4272 tree arg3_type;
4273 tree result = NULL_TREE;
4274 tree result_type = NULL_TREE;
4275 bool lvalue_p = true;
4276 struct z_candidate *candidates = 0;
4277 struct z_candidate *cand;
4278 void *p;
4279
4280 /* As a G++ extension, the second argument to the conditional can be
4281 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4282 c'.) If the second operand is omitted, make sure it is
4283 calculated only once. */
4284 if (!arg2)
4285 {
4286 if (complain & tf_error)
4287 pedwarn (input_location, OPT_pedantic,
4288 "ISO C++ forbids omitting the middle term of a ?: expression");
4289
4290 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4291 if (real_lvalue_p (arg1))
4292 arg2 = arg1 = stabilize_reference (arg1);
4293 else
4294 arg2 = arg1 = save_expr (arg1);
4295 }
4296
4297 /* [expr.cond]
4298
4299 The first expression is implicitly converted to bool (clause
4300 _conv_). */
4301 arg1 = perform_implicit_conversion_flags (boolean_type_node, arg1, complain,
4302 LOOKUP_NORMAL);
4303
4304 /* If something has already gone wrong, just pass that fact up the
4305 tree. */
4306 if (error_operand_p (arg1)
4307 || error_operand_p (arg2)
4308 || error_operand_p (arg3))
4309 return error_mark_node;
4310
4311 /* [expr.cond]
4312
4313 If either the second or the third operand has type (possibly
4314 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4315 array-to-pointer (_conv.array_), and function-to-pointer
4316 (_conv.func_) standard conversions are performed on the second
4317 and third operands. */
4318 arg2_type = unlowered_expr_type (arg2);
4319 arg3_type = unlowered_expr_type (arg3);
4320 if (VOID_TYPE_P (arg2_type) || VOID_TYPE_P (arg3_type))
4321 {
4322 /* Do the conversions. We don't these for `void' type arguments
4323 since it can't have any effect and since decay_conversion
4324 does not handle that case gracefully. */
4325 if (!VOID_TYPE_P (arg2_type))
4326 arg2 = decay_conversion (arg2);
4327 if (!VOID_TYPE_P (arg3_type))
4328 arg3 = decay_conversion (arg3);
4329 arg2_type = TREE_TYPE (arg2);
4330 arg3_type = TREE_TYPE (arg3);
4331
4332 /* [expr.cond]
4333
4334 One of the following shall hold:
4335
4336 --The second or the third operand (but not both) is a
4337 throw-expression (_except.throw_); the result is of the
4338 type of the other and is an rvalue.
4339
4340 --Both the second and the third operands have type void; the
4341 result is of type void and is an rvalue.
4342
4343 We must avoid calling force_rvalue for expressions of type
4344 "void" because it will complain that their value is being
4345 used. */
4346 if (TREE_CODE (arg2) == THROW_EXPR
4347 && TREE_CODE (arg3) != THROW_EXPR)
4348 {
4349 if (!VOID_TYPE_P (arg3_type))
4350 {
4351 arg3 = force_rvalue (arg3, complain);
4352 if (arg3 == error_mark_node)
4353 return error_mark_node;
4354 }
4355 arg3_type = TREE_TYPE (arg3);
4356 result_type = arg3_type;
4357 }
4358 else if (TREE_CODE (arg2) != THROW_EXPR
4359 && TREE_CODE (arg3) == THROW_EXPR)
4360 {
4361 if (!VOID_TYPE_P (arg2_type))
4362 {
4363 arg2 = force_rvalue (arg2, complain);
4364 if (arg2 == error_mark_node)
4365 return error_mark_node;
4366 }
4367 arg2_type = TREE_TYPE (arg2);
4368 result_type = arg2_type;
4369 }
4370 else if (VOID_TYPE_P (arg2_type) && VOID_TYPE_P (arg3_type))
4371 result_type = void_type_node;
4372 else
4373 {
4374 if (complain & tf_error)
4375 {
4376 if (VOID_TYPE_P (arg2_type))
4377 error ("second operand to the conditional operator "
4378 "is of type %<void%>, "
4379 "but the third operand is neither a throw-expression "
4380 "nor of type %<void%>");
4381 else
4382 error ("third operand to the conditional operator "
4383 "is of type %<void%>, "
4384 "but the second operand is neither a throw-expression "
4385 "nor of type %<void%>");
4386 }
4387 return error_mark_node;
4388 }
4389
4390 lvalue_p = false;
4391 goto valid_operands;
4392 }
4393 /* [expr.cond]
4394
4395 Otherwise, if the second and third operand have different types,
4396 and either has (possibly cv-qualified) class type, an attempt is
4397 made to convert each of those operands to the type of the other. */
4398 else if (!same_type_p (arg2_type, arg3_type)
4399 && (CLASS_TYPE_P (arg2_type) || CLASS_TYPE_P (arg3_type)))
4400 {
4401 conversion *conv2;
4402 conversion *conv3;
4403
4404 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4405 p = conversion_obstack_alloc (0);
4406
4407 conv2 = conditional_conversion (arg2, arg3);
4408 conv3 = conditional_conversion (arg3, arg2);
4409
4410 /* [expr.cond]
4411
4412 If both can be converted, or one can be converted but the
4413 conversion is ambiguous, the program is ill-formed. If
4414 neither can be converted, the operands are left unchanged and
4415 further checking is performed as described below. If exactly
4416 one conversion is possible, that conversion is applied to the
4417 chosen operand and the converted operand is used in place of
4418 the original operand for the remainder of this section. */
4419 if ((conv2 && !conv2->bad_p
4420 && conv3 && !conv3->bad_p)
4421 || (conv2 && conv2->kind == ck_ambig)
4422 || (conv3 && conv3->kind == ck_ambig))
4423 {
4424 error ("operands to ?: have different types %qT and %qT",
4425 arg2_type, arg3_type);
4426 result = error_mark_node;
4427 }
4428 else if (conv2 && (!conv2->bad_p || !conv3))
4429 {
4430 arg2 = convert_like (conv2, arg2, complain);
4431 arg2 = convert_from_reference (arg2);
4432 arg2_type = TREE_TYPE (arg2);
4433 /* Even if CONV2 is a valid conversion, the result of the
4434 conversion may be invalid. For example, if ARG3 has type
4435 "volatile X", and X does not have a copy constructor
4436 accepting a "volatile X&", then even if ARG2 can be
4437 converted to X, the conversion will fail. */
4438 if (error_operand_p (arg2))
4439 result = error_mark_node;
4440 }
4441 else if (conv3 && (!conv3->bad_p || !conv2))
4442 {
4443 arg3 = convert_like (conv3, arg3, complain);
4444 arg3 = convert_from_reference (arg3);
4445 arg3_type = TREE_TYPE (arg3);
4446 if (error_operand_p (arg3))
4447 result = error_mark_node;
4448 }
4449
4450 /* Free all the conversions we allocated. */
4451 obstack_free (&conversion_obstack, p);
4452
4453 if (result)
4454 return result;
4455
4456 /* If, after the conversion, both operands have class type,
4457 treat the cv-qualification of both operands as if it were the
4458 union of the cv-qualification of the operands.
4459
4460 The standard is not clear about what to do in this
4461 circumstance. For example, if the first operand has type
4462 "const X" and the second operand has a user-defined
4463 conversion to "volatile X", what is the type of the second
4464 operand after this step? Making it be "const X" (matching
4465 the first operand) seems wrong, as that discards the
4466 qualification without actually performing a copy. Leaving it
4467 as "volatile X" seems wrong as that will result in the
4468 conditional expression failing altogether, even though,
4469 according to this step, the one operand could be converted to
4470 the type of the other. */
4471 if ((conv2 || conv3)
4472 && CLASS_TYPE_P (arg2_type)
4473 && cp_type_quals (arg2_type) != cp_type_quals (arg3_type))
4474 arg2_type = arg3_type =
4475 cp_build_qualified_type (arg2_type,
4476 cp_type_quals (arg2_type)
4477 | cp_type_quals (arg3_type));
4478 }
4479
4480 /* [expr.cond]
4481
4482 If the second and third operands are lvalues and have the same
4483 type, the result is of that type and is an lvalue. */
4484 if (real_lvalue_p (arg2)
4485 && real_lvalue_p (arg3)
4486 && same_type_p (arg2_type, arg3_type))
4487 {
4488 result_type = arg2_type;
4489 arg2 = mark_lvalue_use (arg2);
4490 arg3 = mark_lvalue_use (arg3);
4491 goto valid_operands;
4492 }
4493
4494 /* [expr.cond]
4495
4496 Otherwise, the result is an rvalue. If the second and third
4497 operand do not have the same type, and either has (possibly
4498 cv-qualified) class type, overload resolution is used to
4499 determine the conversions (if any) to be applied to the operands
4500 (_over.match.oper_, _over.built_). */
4501 lvalue_p = false;
4502 if (!same_type_p (arg2_type, arg3_type)
4503 && (CLASS_TYPE_P (arg2_type) || CLASS_TYPE_P (arg3_type)))
4504 {
4505 tree args[3];
4506 conversion *conv;
4507 bool any_viable_p;
4508
4509 /* Rearrange the arguments so that add_builtin_candidate only has
4510 to know about two args. In build_builtin_candidate, the
4511 arguments are unscrambled. */
4512 args[0] = arg2;
4513 args[1] = arg3;
4514 args[2] = arg1;
4515 add_builtin_candidates (&candidates,
4516 COND_EXPR,
4517 NOP_EXPR,
4518 ansi_opname (COND_EXPR),
4519 args,
4520 LOOKUP_NORMAL);
4521
4522 /* [expr.cond]
4523
4524 If the overload resolution fails, the program is
4525 ill-formed. */
4526 candidates = splice_viable (candidates, pedantic, &any_viable_p);
4527 if (!any_viable_p)
4528 {
4529 if (complain & tf_error)
4530 {
4531 op_error (COND_EXPR, NOP_EXPR, arg1, arg2, arg3, FALSE);
4532 print_z_candidates (location_of (arg1), candidates);
4533 }
4534 return error_mark_node;
4535 }
4536 cand = tourney (candidates);
4537 if (!cand)
4538 {
4539 if (complain & tf_error)
4540 {
4541 op_error (COND_EXPR, NOP_EXPR, arg1, arg2, arg3, FALSE);
4542 print_z_candidates (location_of (arg1), candidates);
4543 }
4544 return error_mark_node;
4545 }
4546
4547 /* [expr.cond]
4548
4549 Otherwise, the conversions thus determined are applied, and
4550 the converted operands are used in place of the original
4551 operands for the remainder of this section. */
4552 conv = cand->convs[0];
4553 arg1 = convert_like (conv, arg1, complain);
4554 conv = cand->convs[1];
4555 arg2 = convert_like (conv, arg2, complain);
4556 arg2_type = TREE_TYPE (arg2);
4557 conv = cand->convs[2];
4558 arg3 = convert_like (conv, arg3, complain);
4559 arg3_type = TREE_TYPE (arg3);
4560 }
4561
4562 /* [expr.cond]
4563
4564 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4565 and function-to-pointer (_conv.func_) standard conversions are
4566 performed on the second and third operands.
4567
4568 We need to force the lvalue-to-rvalue conversion here for class types,
4569 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4570 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4571 regions. */
4572
4573 arg2 = force_rvalue (arg2, complain);
4574 if (!CLASS_TYPE_P (arg2_type))
4575 arg2_type = TREE_TYPE (arg2);
4576
4577 arg3 = force_rvalue (arg3, complain);
4578 if (!CLASS_TYPE_P (arg3_type))
4579 arg3_type = TREE_TYPE (arg3);
4580
4581 if (arg2 == error_mark_node || arg3 == error_mark_node)
4582 return error_mark_node;
4583
4584 /* [expr.cond]
4585
4586 After those conversions, one of the following shall hold:
4587
4588 --The second and third operands have the same type; the result is of
4589 that type. */
4590 if (same_type_p (arg2_type, arg3_type))
4591 result_type = arg2_type;
4592 /* [expr.cond]
4593
4594 --The second and third operands have arithmetic or enumeration
4595 type; the usual arithmetic conversions are performed to bring
4596 them to a common type, and the result is of that type. */
4597 else if ((ARITHMETIC_TYPE_P (arg2_type)
4598 || UNSCOPED_ENUM_P (arg2_type))
4599 && (ARITHMETIC_TYPE_P (arg3_type)
4600 || UNSCOPED_ENUM_P (arg3_type)))
4601 {
4602 /* In this case, there is always a common type. */
4603 result_type = type_after_usual_arithmetic_conversions (arg2_type,
4604 arg3_type);
4605 do_warn_double_promotion (result_type, arg2_type, arg3_type,
4606 "implicit conversion from %qT to %qT to "
4607 "match other result of conditional",
4608 input_location);
4609
4610 if (TREE_CODE (arg2_type) == ENUMERAL_TYPE
4611 && TREE_CODE (arg3_type) == ENUMERAL_TYPE)
4612 {
4613 if (complain & tf_warning)
4614 warning (0,
4615 "enumeral mismatch in conditional expression: %qT vs %qT",
4616 arg2_type, arg3_type);
4617 }
4618 else if (extra_warnings
4619 && ((TREE_CODE (arg2_type) == ENUMERAL_TYPE
4620 && !same_type_p (arg3_type, type_promotes_to (arg2_type)))
4621 || (TREE_CODE (arg3_type) == ENUMERAL_TYPE
4622 && !same_type_p (arg2_type, type_promotes_to (arg3_type)))))
4623 {
4624 if (complain & tf_warning)
4625 warning (0,
4626 "enumeral and non-enumeral type in conditional expression");
4627 }
4628
4629 arg2 = perform_implicit_conversion (result_type, arg2, complain);
4630 arg3 = perform_implicit_conversion (result_type, arg3, complain);
4631 }
4632 /* [expr.cond]
4633
4634 --The second and third operands have pointer type, or one has
4635 pointer type and the other is a null pointer constant; pointer
4636 conversions (_conv.ptr_) and qualification conversions
4637 (_conv.qual_) are performed to bring them to their composite
4638 pointer type (_expr.rel_). The result is of the composite
4639 pointer type.
4640
4641 --The second and third operands have pointer to member type, or
4642 one has pointer to member type and the other is a null pointer
4643 constant; pointer to member conversions (_conv.mem_) and
4644 qualification conversions (_conv.qual_) are performed to bring
4645 them to a common type, whose cv-qualification shall match the
4646 cv-qualification of either the second or the third operand.
4647 The result is of the common type. */
4648 else if ((null_ptr_cst_p (arg2)
4649 && (TYPE_PTR_P (arg3_type) || TYPE_PTR_TO_MEMBER_P (arg3_type)))
4650 || (null_ptr_cst_p (arg3)
4651 && (TYPE_PTR_P (arg2_type) || TYPE_PTR_TO_MEMBER_P (arg2_type)))
4652 || (TYPE_PTR_P (arg2_type) && TYPE_PTR_P (arg3_type))
4653 || (TYPE_PTRMEM_P (arg2_type) && TYPE_PTRMEM_P (arg3_type))
4654 || (TYPE_PTRMEMFUNC_P (arg2_type) && TYPE_PTRMEMFUNC_P (arg3_type)))
4655 {
4656 result_type = composite_pointer_type (arg2_type, arg3_type, arg2,
4657 arg3, CPO_CONDITIONAL_EXPR,
4658 complain);
4659 if (result_type == error_mark_node)
4660 return error_mark_node;
4661 arg2 = perform_implicit_conversion (result_type, arg2, complain);
4662 arg3 = perform_implicit_conversion (result_type, arg3, complain);
4663 }
4664
4665 if (!result_type)
4666 {
4667 if (complain & tf_error)
4668 error ("operands to ?: have different types %qT and %qT",
4669 arg2_type, arg3_type);
4670 return error_mark_node;
4671 }
4672
4673 valid_operands:
4674 result = build3 (COND_EXPR, result_type, arg1, arg2, arg3);
4675 if (!cp_unevaluated_operand)
4676 /* Avoid folding within decltype (c++/42013) and noexcept. */
4677 result = fold_if_not_in_template (result);
4678
4679 /* We can't use result_type below, as fold might have returned a
4680 throw_expr. */
4681
4682 if (!lvalue_p)
4683 {
4684 /* Expand both sides into the same slot, hopefully the target of
4685 the ?: expression. We used to check for TARGET_EXPRs here,
4686 but now we sometimes wrap them in NOP_EXPRs so the test would
4687 fail. */
4688 if (CLASS_TYPE_P (TREE_TYPE (result)))
4689 result = get_target_expr (result);
4690 /* If this expression is an rvalue, but might be mistaken for an
4691 lvalue, we must add a NON_LVALUE_EXPR. */
4692 result = rvalue (result);
4693 }
4694
4695 return result;
4696 }
4697
4698 /* Wrapper for above. */
4699
4700 tree
4701 build_conditional_expr (tree arg1, tree arg2, tree arg3,
4702 tsubst_flags_t complain)
4703 {
4704 tree ret;
4705 bool subtime = timevar_cond_start (TV_OVERLOAD);
4706 ret = build_conditional_expr_1 (arg1, arg2, arg3, complain);
4707 timevar_cond_stop (TV_OVERLOAD, subtime);
4708 return ret;
4709 }
4710
4711 /* OPERAND is an operand to an expression. Perform necessary steps
4712 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
4713 returned. */
4714
4715 static tree
4716 prep_operand (tree operand)
4717 {
4718 if (operand)
4719 {
4720 if (CLASS_TYPE_P (TREE_TYPE (operand))
4721 && CLASSTYPE_TEMPLATE_INSTANTIATION (TREE_TYPE (operand)))
4722 /* Make sure the template type is instantiated now. */
4723 instantiate_class_template (TYPE_MAIN_VARIANT (TREE_TYPE (operand)));
4724 }
4725
4726 return operand;
4727 }
4728
4729 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
4730 OVERLOAD) to the CANDIDATES, returning an updated list of
4731 CANDIDATES. The ARGS are the arguments provided to the call;
4732 if FIRST_ARG is non-null it is the implicit object argument,
4733 otherwise the first element of ARGS is used if needed. The
4734 EXPLICIT_TARGS are explicit template arguments provided.
4735 TEMPLATE_ONLY is true if only template functions should be
4736 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
4737 add_function_candidate. */
4738
4739 static void
4740 add_candidates (tree fns, tree first_arg, const VEC(tree,gc) *args,
4741 tree return_type,
4742 tree explicit_targs, bool template_only,
4743 tree conversion_path, tree access_path,
4744 int flags,
4745 struct z_candidate **candidates)
4746 {
4747 tree ctype;
4748 const VEC(tree,gc) *non_static_args;
4749 bool check_list_ctor;
4750 bool check_converting;
4751 unification_kind_t strict;
4752 tree fn;
4753
4754 if (!fns)
4755 return;
4756
4757 /* Precalculate special handling of constructors and conversion ops. */
4758 fn = OVL_CURRENT (fns);
4759 if (DECL_CONV_FN_P (fn))
4760 {
4761 check_list_ctor = false;
4762 check_converting = !!(flags & LOOKUP_ONLYCONVERTING);
4763 if (flags & LOOKUP_NO_CONVERSION)
4764 /* We're doing return_type(x). */
4765 strict = DEDUCE_CONV;
4766 else
4767 /* We're doing x.operator return_type(). */
4768 strict = DEDUCE_EXACT;
4769 /* [over.match.funcs] For conversion functions, the function
4770 is considered to be a member of the class of the implicit
4771 object argument for the purpose of defining the type of
4772 the implicit object parameter. */
4773 ctype = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (first_arg)));
4774 }
4775 else
4776 {
4777 if (DECL_CONSTRUCTOR_P (fn))
4778 {
4779 check_list_ctor = !!(flags & LOOKUP_LIST_ONLY);
4780 check_converting = !!(flags & LOOKUP_ONLYCONVERTING);
4781 }
4782 else
4783 {
4784 check_list_ctor = false;
4785 check_converting = false;
4786 }
4787 strict = DEDUCE_CALL;
4788 ctype = conversion_path ? BINFO_TYPE (conversion_path) : NULL_TREE;
4789 }
4790
4791 if (first_arg)
4792 non_static_args = args;
4793 else
4794 /* Delay creating the implicit this parameter until it is needed. */
4795 non_static_args = NULL;
4796
4797 for (; fns; fns = OVL_NEXT (fns))
4798 {
4799 tree fn_first_arg;
4800 const VEC(tree,gc) *fn_args;
4801
4802 fn = OVL_CURRENT (fns);
4803
4804 if (check_converting && DECL_NONCONVERTING_P (fn))
4805 continue;
4806 if (check_list_ctor && !is_list_ctor (fn))
4807 continue;
4808
4809 /* Figure out which set of arguments to use. */
4810 if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn))
4811 {
4812 /* If this function is a non-static member and we didn't get an
4813 implicit object argument, move it out of args. */
4814 if (first_arg == NULL_TREE)
4815 {
4816 unsigned int ix;
4817 tree arg;
4818 VEC(tree,gc) *tempvec
4819 = VEC_alloc (tree, gc, VEC_length (tree, args) - 1);
4820 for (ix = 1; VEC_iterate (tree, args, ix, arg); ++ix)
4821 VEC_quick_push (tree, tempvec, arg);
4822 non_static_args = tempvec;
4823 first_arg = build_this (VEC_index (tree, args, 0));
4824 }
4825
4826 fn_first_arg = first_arg;
4827 fn_args = non_static_args;
4828 }
4829 else
4830 {
4831 /* Otherwise, just use the list of arguments provided. */
4832 fn_first_arg = NULL_TREE;
4833 fn_args = args;
4834 }
4835
4836 if (TREE_CODE (fn) == TEMPLATE_DECL)
4837 add_template_candidate (candidates,
4838 fn,
4839 ctype,
4840 explicit_targs,
4841 fn_first_arg,
4842 fn_args,
4843 return_type,
4844 access_path,
4845 conversion_path,
4846 flags,
4847 strict);
4848 else if (!template_only)
4849 add_function_candidate (candidates,
4850 fn,
4851 ctype,
4852 fn_first_arg,
4853 fn_args,
4854 access_path,
4855 conversion_path,
4856 flags);
4857 }
4858 }
4859
4860 /* Even unsigned enum types promote to signed int. We don't want to
4861 issue -Wsign-compare warnings for this case. Here ORIG_ARG is the
4862 original argument and ARG is the argument after any conversions
4863 have been applied. We set TREE_NO_WARNING if we have added a cast
4864 from an unsigned enum type to a signed integer type. */
4865
4866 static void
4867 avoid_sign_compare_warnings (tree orig_arg, tree arg)
4868 {
4869 if (orig_arg != NULL_TREE
4870 && arg != NULL_TREE
4871 && orig_arg != arg
4872 && TREE_CODE (TREE_TYPE (orig_arg)) == ENUMERAL_TYPE
4873 && TYPE_UNSIGNED (TREE_TYPE (orig_arg))
4874 && INTEGRAL_TYPE_P (TREE_TYPE (arg))
4875 && !TYPE_UNSIGNED (TREE_TYPE (arg)))
4876 TREE_NO_WARNING (arg) = 1;
4877 }
4878
4879 static tree
4880 build_new_op_1 (enum tree_code code, int flags, tree arg1, tree arg2, tree arg3,
4881 tree *overload, tsubst_flags_t complain)
4882 {
4883 tree orig_arg1 = arg1;
4884 tree orig_arg2 = arg2;
4885 tree orig_arg3 = arg3;
4886 struct z_candidate *candidates = 0, *cand;
4887 VEC(tree,gc) *arglist;
4888 tree fnname;
4889 tree args[3];
4890 tree result = NULL_TREE;
4891 bool result_valid_p = false;
4892 enum tree_code code2 = NOP_EXPR;
4893 enum tree_code code_orig_arg1 = ERROR_MARK;
4894 enum tree_code code_orig_arg2 = ERROR_MARK;
4895 conversion *conv;
4896 void *p;
4897 bool strict_p;
4898 bool any_viable_p;
4899
4900 if (error_operand_p (arg1)
4901 || error_operand_p (arg2)
4902 || error_operand_p (arg3))
4903 return error_mark_node;
4904
4905 if (code == MODIFY_EXPR)
4906 {
4907 code2 = TREE_CODE (arg3);
4908 arg3 = NULL_TREE;
4909 fnname = ansi_assopname (code2);
4910 }
4911 else
4912 fnname = ansi_opname (code);
4913
4914 arg1 = prep_operand (arg1);
4915
4916 switch (code)
4917 {
4918 case NEW_EXPR:
4919 case VEC_NEW_EXPR:
4920 case VEC_DELETE_EXPR:
4921 case DELETE_EXPR:
4922 /* Use build_op_new_call and build_op_delete_call instead. */
4923 gcc_unreachable ();
4924
4925 case CALL_EXPR:
4926 /* Use build_op_call instead. */
4927 gcc_unreachable ();
4928
4929 case TRUTH_ORIF_EXPR:
4930 case TRUTH_ANDIF_EXPR:
4931 case TRUTH_AND_EXPR:
4932 case TRUTH_OR_EXPR:
4933 /* These are saved for the sake of warn_logical_operator. */
4934 code_orig_arg1 = TREE_CODE (arg1);
4935 code_orig_arg2 = TREE_CODE (arg2);
4936
4937 default:
4938 break;
4939 }
4940
4941 arg2 = prep_operand (arg2);
4942 arg3 = prep_operand (arg3);
4943
4944 if (code == COND_EXPR)
4945 /* Use build_conditional_expr instead. */
4946 gcc_unreachable ();
4947 else if (! IS_OVERLOAD_TYPE (TREE_TYPE (arg1))
4948 && (! arg2 || ! IS_OVERLOAD_TYPE (TREE_TYPE (arg2))))
4949 goto builtin;
4950
4951 if (code == POSTINCREMENT_EXPR || code == POSTDECREMENT_EXPR)
4952 arg2 = integer_zero_node;
4953
4954 arglist = VEC_alloc (tree, gc, 3);
4955 VEC_quick_push (tree, arglist, arg1);
4956 if (arg2 != NULL_TREE)
4957 VEC_quick_push (tree, arglist, arg2);
4958 if (arg3 != NULL_TREE)
4959 VEC_quick_push (tree, arglist, arg3);
4960
4961 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4962 p = conversion_obstack_alloc (0);
4963
4964 /* Add namespace-scope operators to the list of functions to
4965 consider. */
4966 add_candidates (lookup_function_nonclass (fnname, arglist, /*block_p=*/true),
4967 NULL_TREE, arglist, NULL_TREE,
4968 NULL_TREE, false, NULL_TREE, NULL_TREE,
4969 flags, &candidates);
4970 /* Add class-member operators to the candidate set. */
4971 if (CLASS_TYPE_P (TREE_TYPE (arg1)))
4972 {
4973 tree fns;
4974
4975 fns = lookup_fnfields (TREE_TYPE (arg1), fnname, 1);
4976 if (fns == error_mark_node)
4977 {
4978 result = error_mark_node;
4979 goto user_defined_result_ready;
4980 }
4981 if (fns)
4982 add_candidates (BASELINK_FUNCTIONS (fns),
4983 NULL_TREE, arglist, NULL_TREE,
4984 NULL_TREE, false,
4985 BASELINK_BINFO (fns),
4986 BASELINK_ACCESS_BINFO (fns),
4987 flags, &candidates);
4988 }
4989
4990 args[0] = arg1;
4991 args[1] = arg2;
4992 args[2] = NULL_TREE;
4993
4994 add_builtin_candidates (&candidates, code, code2, fnname, args, flags);
4995
4996 switch (code)
4997 {
4998 case COMPOUND_EXPR:
4999 case ADDR_EXPR:
5000 /* For these, the built-in candidates set is empty
5001 [over.match.oper]/3. We don't want non-strict matches
5002 because exact matches are always possible with built-in
5003 operators. The built-in candidate set for COMPONENT_REF
5004 would be empty too, but since there are no such built-in
5005 operators, we accept non-strict matches for them. */
5006 strict_p = true;
5007 break;
5008
5009 default:
5010 strict_p = pedantic;
5011 break;
5012 }
5013
5014 candidates = splice_viable (candidates, strict_p, &any_viable_p);
5015 if (!any_viable_p)
5016 {
5017 switch (code)
5018 {
5019 case POSTINCREMENT_EXPR:
5020 case POSTDECREMENT_EXPR:
5021 /* Don't try anything fancy if we're not allowed to produce
5022 errors. */
5023 if (!(complain & tf_error))
5024 return error_mark_node;
5025
5026 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5027 distinguish between prefix and postfix ++ and
5028 operator++() was used for both, so we allow this with
5029 -fpermissive. */
5030 if (flags & LOOKUP_COMPLAIN)
5031 {
5032 const char *msg = (flag_permissive)
5033 ? G_("no %<%D(int)%> declared for postfix %qs,"
5034 " trying prefix operator instead")
5035 : G_("no %<%D(int)%> declared for postfix %qs");
5036 permerror (input_location, msg, fnname,
5037 operator_name_info[code].name);
5038 }
5039
5040 if (!flag_permissive)
5041 return error_mark_node;
5042
5043 if (code == POSTINCREMENT_EXPR)
5044 code = PREINCREMENT_EXPR;
5045 else
5046 code = PREDECREMENT_EXPR;
5047 result = build_new_op_1 (code, flags, arg1, NULL_TREE, NULL_TREE,
5048 overload, complain);
5049 break;
5050
5051 /* The caller will deal with these. */
5052 case ADDR_EXPR:
5053 case COMPOUND_EXPR:
5054 case COMPONENT_REF:
5055 result = NULL_TREE;
5056 result_valid_p = true;
5057 break;
5058
5059 default:
5060 if ((flags & LOOKUP_COMPLAIN) && (complain & tf_error))
5061 {
5062 /* If one of the arguments of the operator represents
5063 an invalid use of member function pointer, try to report
5064 a meaningful error ... */
5065 if (invalid_nonstatic_memfn_p (arg1, tf_error)
5066 || invalid_nonstatic_memfn_p (arg2, tf_error)
5067 || invalid_nonstatic_memfn_p (arg3, tf_error))
5068 /* We displayed the error message. */;
5069 else
5070 {
5071 /* ... Otherwise, report the more generic
5072 "no matching operator found" error */
5073 op_error (code, code2, arg1, arg2, arg3, FALSE);
5074 print_z_candidates (input_location, candidates);
5075 }
5076 }
5077 result = error_mark_node;
5078 break;
5079 }
5080 }
5081 else
5082 {
5083 cand = tourney (candidates);
5084 if (cand == 0)
5085 {
5086 if ((flags & LOOKUP_COMPLAIN) && (complain & tf_error))
5087 {
5088 op_error (code, code2, arg1, arg2, arg3, TRUE);
5089 print_z_candidates (input_location, candidates);
5090 }
5091 result = error_mark_node;
5092 }
5093 else if (TREE_CODE (cand->fn) == FUNCTION_DECL)
5094 {
5095 if (overload)
5096 *overload = cand->fn;
5097
5098 if (resolve_args (arglist, complain) == NULL)
5099 result = error_mark_node;
5100 else
5101 result = build_over_call (cand, LOOKUP_NORMAL, complain);
5102 }
5103 else
5104 {
5105 /* Give any warnings we noticed during overload resolution. */
5106 if (cand->warnings && (complain & tf_warning))
5107 {
5108 struct candidate_warning *w;
5109 for (w = cand->warnings; w; w = w->next)
5110 joust (cand, w->loser, 1);
5111 }
5112
5113 /* Check for comparison of different enum types. */
5114 switch (code)
5115 {
5116 case GT_EXPR:
5117 case LT_EXPR:
5118 case GE_EXPR:
5119 case LE_EXPR:
5120 case EQ_EXPR:
5121 case NE_EXPR:
5122 if (TREE_CODE (TREE_TYPE (arg1)) == ENUMERAL_TYPE
5123 && TREE_CODE (TREE_TYPE (arg2)) == ENUMERAL_TYPE
5124 && (TYPE_MAIN_VARIANT (TREE_TYPE (arg1))
5125 != TYPE_MAIN_VARIANT (TREE_TYPE (arg2)))
5126 && (complain & tf_warning))
5127 {
5128 warning (OPT_Wenum_compare,
5129 "comparison between %q#T and %q#T",
5130 TREE_TYPE (arg1), TREE_TYPE (arg2));
5131 }
5132 break;
5133 default:
5134 break;
5135 }
5136
5137 /* We need to strip any leading REF_BIND so that bitfields
5138 don't cause errors. This should not remove any important
5139 conversions, because builtins don't apply to class
5140 objects directly. */
5141 conv = cand->convs[0];
5142 if (conv->kind == ck_ref_bind)
5143 conv = conv->u.next;
5144 arg1 = convert_like (conv, arg1, complain);
5145
5146 if (arg2)
5147 {
5148 /* We need to call warn_logical_operator before
5149 converting arg2 to a boolean_type. */
5150 if (complain & tf_warning)
5151 warn_logical_operator (input_location, code, boolean_type_node,
5152 code_orig_arg1, arg1,
5153 code_orig_arg2, arg2);
5154
5155 conv = cand->convs[1];
5156 if (conv->kind == ck_ref_bind)
5157 conv = conv->u.next;
5158 arg2 = convert_like (conv, arg2, complain);
5159 }
5160 if (arg3)
5161 {
5162 conv = cand->convs[2];
5163 if (conv->kind == ck_ref_bind)
5164 conv = conv->u.next;
5165 arg3 = convert_like (conv, arg3, complain);
5166 }
5167
5168 }
5169 }
5170
5171 user_defined_result_ready:
5172
5173 /* Free all the conversions we allocated. */
5174 obstack_free (&conversion_obstack, p);
5175
5176 if (result || result_valid_p)
5177 return result;
5178
5179 builtin:
5180 avoid_sign_compare_warnings (orig_arg1, arg1);
5181 avoid_sign_compare_warnings (orig_arg2, arg2);
5182 avoid_sign_compare_warnings (orig_arg3, arg3);
5183
5184 switch (code)
5185 {
5186 case MODIFY_EXPR:
5187 return cp_build_modify_expr (arg1, code2, arg2, complain);
5188
5189 case INDIRECT_REF:
5190 return cp_build_indirect_ref (arg1, RO_UNARY_STAR, complain);
5191
5192 case TRUTH_ANDIF_EXPR:
5193 case TRUTH_ORIF_EXPR:
5194 case TRUTH_AND_EXPR:
5195 case TRUTH_OR_EXPR:
5196 warn_logical_operator (input_location, code, boolean_type_node,
5197 code_orig_arg1, arg1, code_orig_arg2, arg2);
5198 /* Fall through. */
5199 case PLUS_EXPR:
5200 case MINUS_EXPR:
5201 case MULT_EXPR:
5202 case TRUNC_DIV_EXPR:
5203 case GT_EXPR:
5204 case LT_EXPR:
5205 case GE_EXPR:
5206 case LE_EXPR:
5207 case EQ_EXPR:
5208 case NE_EXPR:
5209 case MAX_EXPR:
5210 case MIN_EXPR:
5211 case LSHIFT_EXPR:
5212 case RSHIFT_EXPR:
5213 case TRUNC_MOD_EXPR:
5214 case BIT_AND_EXPR:
5215 case BIT_IOR_EXPR:
5216 case BIT_XOR_EXPR:
5217 return cp_build_binary_op (input_location, code, arg1, arg2, complain);
5218
5219 case UNARY_PLUS_EXPR:
5220 case NEGATE_EXPR:
5221 case BIT_NOT_EXPR:
5222 case TRUTH_NOT_EXPR:
5223 case PREINCREMENT_EXPR:
5224 case POSTINCREMENT_EXPR:
5225 case PREDECREMENT_EXPR:
5226 case POSTDECREMENT_EXPR:
5227 case REALPART_EXPR:
5228 case IMAGPART_EXPR:
5229 case ABS_EXPR:
5230 return cp_build_unary_op (code, arg1, candidates != 0, complain);
5231
5232 case ARRAY_REF:
5233 return cp_build_array_ref (input_location, arg1, arg2, complain);
5234
5235 case MEMBER_REF:
5236 return build_m_component_ref (cp_build_indirect_ref (arg1, RO_NULL,
5237 complain),
5238 arg2);
5239
5240 /* The caller will deal with these. */
5241 case ADDR_EXPR:
5242 case COMPONENT_REF:
5243 case COMPOUND_EXPR:
5244 return NULL_TREE;
5245
5246 default:
5247 gcc_unreachable ();
5248 }
5249 return NULL_TREE;
5250 }
5251
5252 /* Wrapper for above. */
5253
5254 tree
5255 build_new_op (enum tree_code code, int flags, tree arg1, tree arg2, tree arg3,
5256 tree *overload, tsubst_flags_t complain)
5257 {
5258 tree ret;
5259 bool subtime = timevar_cond_start (TV_OVERLOAD);
5260 ret = build_new_op_1 (code, flags, arg1, arg2, arg3, overload, complain);
5261 timevar_cond_stop (TV_OVERLOAD, subtime);
5262 return ret;
5263 }
5264
5265 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5266 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5267
5268 static bool
5269 non_placement_deallocation_fn_p (tree t)
5270 {
5271 /* A template instance is never a usual deallocation function,
5272 regardless of its signature. */
5273 if (TREE_CODE (t) == TEMPLATE_DECL
5274 || primary_template_instantiation_p (t))
5275 return false;
5276
5277 /* If a class T has a member deallocation function named operator delete
5278 with exactly one parameter, then that function is a usual
5279 (non-placement) deallocation function. If class T does not declare
5280 such an operator delete but does declare a member deallocation
5281 function named operator delete with exactly two parameters, the second
5282 of which has type std::size_t (18.2), then this function is a usual
5283 deallocation function. */
5284 t = FUNCTION_ARG_CHAIN (t);
5285 if (t == void_list_node
5286 || (t && same_type_p (TREE_VALUE (t), size_type_node)
5287 && TREE_CHAIN (t) == void_list_node))
5288 return true;
5289 return false;
5290 }
5291
5292 /* Build a call to operator delete. This has to be handled very specially,
5293 because the restrictions on what signatures match are different from all
5294 other call instances. For a normal delete, only a delete taking (void *)
5295 or (void *, size_t) is accepted. For a placement delete, only an exact
5296 match with the placement new is accepted.
5297
5298 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5299 ADDR is the pointer to be deleted.
5300 SIZE is the size of the memory block to be deleted.
5301 GLOBAL_P is true if the delete-expression should not consider
5302 class-specific delete operators.
5303 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5304
5305 If this call to "operator delete" is being generated as part to
5306 deallocate memory allocated via a new-expression (as per [expr.new]
5307 which requires that if the initialization throws an exception then
5308 we call a deallocation function), then ALLOC_FN is the allocation
5309 function. */
5310
5311 tree
5312 build_op_delete_call (enum tree_code code, tree addr, tree size,
5313 bool global_p, tree placement,
5314 tree alloc_fn)
5315 {
5316 tree fn = NULL_TREE;
5317 tree fns, fnname, type, t;
5318
5319 if (addr == error_mark_node)
5320 return error_mark_node;
5321
5322 type = strip_array_types (TREE_TYPE (TREE_TYPE (addr)));
5323
5324 fnname = ansi_opname (code);
5325
5326 if (CLASS_TYPE_P (type)
5327 && COMPLETE_TYPE_P (complete_type (type))
5328 && !global_p)
5329 /* In [class.free]
5330
5331 If the result of the lookup is ambiguous or inaccessible, or if
5332 the lookup selects a placement deallocation function, the
5333 program is ill-formed.
5334
5335 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5336 {
5337 fns = lookup_fnfields (TYPE_BINFO (type), fnname, 1);
5338 if (fns == error_mark_node)
5339 return error_mark_node;
5340 }
5341 else
5342 fns = NULL_TREE;
5343
5344 if (fns == NULL_TREE)
5345 fns = lookup_name_nonclass (fnname);
5346
5347 /* Strip const and volatile from addr. */
5348 addr = cp_convert (ptr_type_node, addr);
5349
5350 if (placement)
5351 {
5352 /* "A declaration of a placement deallocation function matches the
5353 declaration of a placement allocation function if it has the same
5354 number of parameters and, after parameter transformations (8.3.5),
5355 all parameter types except the first are identical."
5356
5357 So we build up the function type we want and ask instantiate_type
5358 to get it for us. */
5359 t = FUNCTION_ARG_CHAIN (alloc_fn);
5360 t = tree_cons (NULL_TREE, ptr_type_node, t);
5361 t = build_function_type (void_type_node, t);
5362
5363 fn = instantiate_type (t, fns, tf_none);
5364 if (fn == error_mark_node)
5365 return NULL_TREE;
5366
5367 if (BASELINK_P (fn))
5368 fn = BASELINK_FUNCTIONS (fn);
5369
5370 /* "If the lookup finds the two-parameter form of a usual deallocation
5371 function (3.7.4.2) and that function, considered as a placement
5372 deallocation function, would have been selected as a match for the
5373 allocation function, the program is ill-formed." */
5374 if (non_placement_deallocation_fn_p (fn))
5375 {
5376 /* But if the class has an operator delete (void *), then that is
5377 the usual deallocation function, so we shouldn't complain
5378 about using the operator delete (void *, size_t). */
5379 for (t = BASELINK_P (fns) ? BASELINK_FUNCTIONS (fns) : fns;
5380 t; t = OVL_NEXT (t))
5381 {
5382 tree elt = OVL_CURRENT (t);
5383 if (non_placement_deallocation_fn_p (elt)
5384 && FUNCTION_ARG_CHAIN (elt) == void_list_node)
5385 goto ok;
5386 }
5387 permerror (0, "non-placement deallocation function %q+D", fn);
5388 permerror (input_location, "selected for placement delete");
5389 ok:;
5390 }
5391 }
5392 else
5393 /* "Any non-placement deallocation function matches a non-placement
5394 allocation function. If the lookup finds a single matching
5395 deallocation function, that function will be called; otherwise, no
5396 deallocation function will be called." */
5397 for (t = BASELINK_P (fns) ? BASELINK_FUNCTIONS (fns) : fns;
5398 t; t = OVL_NEXT (t))
5399 {
5400 tree elt = OVL_CURRENT (t);
5401 if (non_placement_deallocation_fn_p (elt))
5402 {
5403 fn = elt;
5404 /* "If a class T has a member deallocation function named
5405 operator delete with exactly one parameter, then that
5406 function is a usual (non-placement) deallocation
5407 function. If class T does not declare such an operator
5408 delete but does declare a member deallocation function named
5409 operator delete with exactly two parameters, the second of
5410 which has type std::size_t (18.2), then this function is a
5411 usual deallocation function."
5412
5413 So (void*) beats (void*, size_t). */
5414 if (FUNCTION_ARG_CHAIN (fn) == void_list_node)
5415 break;
5416 }
5417 }
5418
5419 /* If we have a matching function, call it. */
5420 if (fn)
5421 {
5422 gcc_assert (TREE_CODE (fn) == FUNCTION_DECL);
5423
5424 /* If the FN is a member function, make sure that it is
5425 accessible. */
5426 if (BASELINK_P (fns))
5427 perform_or_defer_access_check (BASELINK_BINFO (fns), fn, fn);
5428
5429 /* Core issue 901: It's ok to new a type with deleted delete. */
5430 if (DECL_DELETED_FN (fn) && alloc_fn)
5431 return NULL_TREE;
5432
5433 if (placement)
5434 {
5435 /* The placement args might not be suitable for overload
5436 resolution at this point, so build the call directly. */
5437 int nargs = call_expr_nargs (placement);
5438 tree *argarray = XALLOCAVEC (tree, nargs);
5439 int i;
5440 argarray[0] = addr;
5441 for (i = 1; i < nargs; i++)
5442 argarray[i] = CALL_EXPR_ARG (placement, i);
5443 mark_used (fn);
5444 return build_cxx_call (fn, nargs, argarray);
5445 }
5446 else
5447 {
5448 tree ret;
5449 VEC(tree,gc) *args = VEC_alloc (tree, gc, 2);
5450 VEC_quick_push (tree, args, addr);
5451 if (FUNCTION_ARG_CHAIN (fn) != void_list_node)
5452 VEC_quick_push (tree, args, size);
5453 ret = cp_build_function_call_vec (fn, &args, tf_warning_or_error);
5454 VEC_free (tree, gc, args);
5455 return ret;
5456 }
5457 }
5458
5459 /* [expr.new]
5460
5461 If no unambiguous matching deallocation function can be found,
5462 propagating the exception does not cause the object's memory to
5463 be freed. */
5464 if (alloc_fn)
5465 {
5466 if (!placement)
5467 warning (0, "no corresponding deallocation function for %qD",
5468 alloc_fn);
5469 return NULL_TREE;
5470 }
5471
5472 error ("no suitable %<operator %s%> for %qT",
5473 operator_name_info[(int)code].name, type);
5474 return error_mark_node;
5475 }
5476
5477 /* If the current scope isn't allowed to access DECL along
5478 BASETYPE_PATH, give an error. The most derived class in
5479 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
5480 the declaration to use in the error diagnostic. */
5481
5482 bool
5483 enforce_access (tree basetype_path, tree decl, tree diag_decl)
5484 {
5485 gcc_assert (TREE_CODE (basetype_path) == TREE_BINFO);
5486
5487 if (!accessible_p (basetype_path, decl, true))
5488 {
5489 if (TREE_PRIVATE (decl))
5490 error ("%q+#D is private", diag_decl);
5491 else if (TREE_PROTECTED (decl))
5492 error ("%q+#D is protected", diag_decl);
5493 else
5494 error ("%q+#D is inaccessible", diag_decl);
5495 error ("within this context");
5496 return false;
5497 }
5498
5499 return true;
5500 }
5501
5502 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
5503 bitwise or of LOOKUP_* values. If any errors are warnings are
5504 generated, set *DIAGNOSTIC_FN to "error" or "warning",
5505 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
5506 to NULL. */
5507
5508 static tree
5509 build_temp (tree expr, tree type, int flags,
5510 diagnostic_t *diagnostic_kind, tsubst_flags_t complain)
5511 {
5512 int savew, savee;
5513 VEC(tree,gc) *args;
5514
5515 savew = warningcount, savee = errorcount;
5516 args = make_tree_vector_single (expr);
5517 expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
5518 &args, type, flags, complain);
5519 release_tree_vector (args);
5520 if (warningcount > savew)
5521 *diagnostic_kind = DK_WARNING;
5522 else if (errorcount > savee)
5523 *diagnostic_kind = DK_ERROR;
5524 else
5525 *diagnostic_kind = DK_UNSPECIFIED;
5526 return expr;
5527 }
5528
5529 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
5530 EXPR is implicitly converted to type TOTYPE.
5531 FN and ARGNUM are used for diagnostics. */
5532
5533 static void
5534 conversion_null_warnings (tree totype, tree expr, tree fn, int argnum)
5535 {
5536 /* Issue warnings about peculiar, but valid, uses of NULL. */
5537 if (expr == null_node && TREE_CODE (totype) != BOOLEAN_TYPE
5538 && ARITHMETIC_TYPE_P (totype))
5539 {
5540 if (fn)
5541 warning_at (input_location, OPT_Wconversion_null,
5542 "passing NULL to non-pointer argument %P of %qD",
5543 argnum, fn);
5544 else
5545 warning_at (input_location, OPT_Wconversion_null,
5546 "converting to non-pointer type %qT from NULL", totype);
5547 }
5548
5549 /* Issue warnings if "false" is converted to a NULL pointer */
5550 else if (TREE_CODE (TREE_TYPE (expr)) == BOOLEAN_TYPE
5551 && TYPE_PTR_P (totype))
5552 {
5553 if (fn)
5554 warning_at (input_location, OPT_Wconversion_null,
5555 "converting %<false%> to pointer type for argument %P "
5556 "of %qD", argnum, fn);
5557 else
5558 warning_at (input_location, OPT_Wconversion_null,
5559 "converting %<false%> to pointer type %qT", totype);
5560 }
5561 }
5562
5563 /* Perform the conversions in CONVS on the expression EXPR. FN and
5564 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
5565 indicates the `this' argument of a method. INNER is nonzero when
5566 being called to continue a conversion chain. It is negative when a
5567 reference binding will be applied, positive otherwise. If
5568 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
5569 conversions will be emitted if appropriate. If C_CAST_P is true,
5570 this conversion is coming from a C-style cast; in that case,
5571 conversions to inaccessible bases are permitted. */
5572
5573 static tree
5574 convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
5575 int inner, bool issue_conversion_warnings,
5576 bool c_cast_p, tsubst_flags_t complain)
5577 {
5578 tree totype = convs->type;
5579 diagnostic_t diag_kind;
5580 int flags;
5581
5582 if (convs->bad_p && !(complain & tf_error))
5583 return error_mark_node;
5584
5585 if (convs->bad_p
5586 && convs->kind != ck_user
5587 && convs->kind != ck_list
5588 && convs->kind != ck_ambig
5589 && (convs->kind != ck_ref_bind
5590 || convs->user_conv_p)
5591 && convs->kind != ck_rvalue
5592 && convs->kind != ck_base)
5593 {
5594 conversion *t = convs;
5595
5596 /* Give a helpful error if this is bad because of excess braces. */
5597 if (BRACE_ENCLOSED_INITIALIZER_P (expr)
5598 && SCALAR_TYPE_P (totype)
5599 && CONSTRUCTOR_NELTS (expr) > 0
5600 && BRACE_ENCLOSED_INITIALIZER_P (CONSTRUCTOR_ELT (expr, 0)->value))
5601 permerror (input_location, "too many braces around initializer for %qT", totype);
5602
5603 for (; t; t = t->u.next)
5604 {
5605 if (t->kind == ck_user && t->cand->reason)
5606 {
5607 permerror (input_location, "invalid user-defined conversion "
5608 "from %qT to %qT", TREE_TYPE (expr), totype);
5609 print_z_candidate ("candidate is:", t->cand);
5610 expr = convert_like_real (t, expr, fn, argnum, 1,
5611 /*issue_conversion_warnings=*/false,
5612 /*c_cast_p=*/false,
5613 complain);
5614 if (convs->kind == ck_ref_bind)
5615 return convert_to_reference (totype, expr, CONV_IMPLICIT,
5616 LOOKUP_NORMAL, NULL_TREE);
5617 else
5618 return cp_convert (totype, expr);
5619 }
5620 else if (t->kind == ck_user || !t->bad_p)
5621 {
5622 expr = convert_like_real (t, expr, fn, argnum, 1,
5623 /*issue_conversion_warnings=*/false,
5624 /*c_cast_p=*/false,
5625 complain);
5626 break;
5627 }
5628 else if (t->kind == ck_ambig)
5629 return convert_like_real (t, expr, fn, argnum, 1,
5630 /*issue_conversion_warnings=*/false,
5631 /*c_cast_p=*/false,
5632 complain);
5633 else if (t->kind == ck_identity)
5634 break;
5635 }
5636
5637 permerror (input_location, "invalid conversion from %qT to %qT",
5638 TREE_TYPE (expr), totype);
5639 if (fn)
5640 permerror (DECL_SOURCE_LOCATION (fn),
5641 " initializing argument %P of %qD", argnum, fn);
5642
5643 return cp_convert (totype, expr);
5644 }
5645
5646 if (issue_conversion_warnings && (complain & tf_warning))
5647 conversion_null_warnings (totype, expr, fn, argnum);
5648
5649 switch (convs->kind)
5650 {
5651 case ck_user:
5652 {
5653 struct z_candidate *cand = convs->cand;
5654 tree convfn = cand->fn;
5655 unsigned i;
5656
5657 /* If we're initializing from {}, it's value-initialization. */
5658 if (BRACE_ENCLOSED_INITIALIZER_P (expr)
5659 && CONSTRUCTOR_NELTS (expr) == 0
5660 && TYPE_HAS_DEFAULT_CONSTRUCTOR (totype))
5661 {
5662 bool direct = CONSTRUCTOR_IS_DIRECT_INIT (expr);
5663 expr = build_value_init (totype, complain);
5664 expr = get_target_expr_sfinae (expr, complain);
5665 if (expr != error_mark_node)
5666 {
5667 TARGET_EXPR_LIST_INIT_P (expr) = true;
5668 TARGET_EXPR_DIRECT_INIT_P (expr) = direct;
5669 }
5670 return expr;
5671 }
5672
5673 expr = mark_rvalue_use (expr);
5674
5675 /* When converting from an init list we consider explicit
5676 constructors, but actually trying to call one is an error. */
5677 if (DECL_NONCONVERTING_P (convfn) && DECL_CONSTRUCTOR_P (convfn)
5678 /* Unless this is for direct-list-initialization. */
5679 && !(BRACE_ENCLOSED_INITIALIZER_P (expr)
5680 && CONSTRUCTOR_IS_DIRECT_INIT (expr))
5681 /* Unless we're calling it for value-initialization from an
5682 empty list, since that is handled separately in 8.5.4. */
5683 && cand->num_convs > 0)
5684 {
5685 error ("converting to %qT from initializer list would use "
5686 "explicit constructor %qD", totype, convfn);
5687 }
5688
5689 /* Set user_conv_p on the argument conversions, so rvalue/base
5690 handling knows not to allow any more UDCs. */
5691 for (i = 0; i < cand->num_convs; ++i)
5692 cand->convs[i]->user_conv_p = true;
5693
5694 expr = build_over_call (cand, LOOKUP_NORMAL, complain);
5695
5696 /* If this is a constructor or a function returning an aggr type,
5697 we need to build up a TARGET_EXPR. */
5698 if (DECL_CONSTRUCTOR_P (convfn))
5699 {
5700 expr = build_cplus_new (totype, expr, complain);
5701
5702 /* Remember that this was list-initialization. */
5703 if (convs->check_narrowing && expr != error_mark_node)
5704 TARGET_EXPR_LIST_INIT_P (expr) = true;
5705 }
5706
5707 return expr;
5708 }
5709 case ck_identity:
5710 expr = mark_rvalue_use (expr);
5711 if (BRACE_ENCLOSED_INITIALIZER_P (expr))
5712 {
5713 int nelts = CONSTRUCTOR_NELTS (expr);
5714 if (nelts == 0)
5715 expr = build_value_init (totype, complain);
5716 else if (nelts == 1)
5717 expr = CONSTRUCTOR_ELT (expr, 0)->value;
5718 else
5719 gcc_unreachable ();
5720 }
5721
5722 if (type_unknown_p (expr))
5723 expr = instantiate_type (totype, expr, complain);
5724 /* Convert a constant to its underlying value, unless we are
5725 about to bind it to a reference, in which case we need to
5726 leave it as an lvalue. */
5727 if (inner >= 0)
5728 {
5729 expr = decl_constant_value_safe (expr);
5730 if (expr == null_node && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (totype))
5731 /* If __null has been converted to an integer type, we do not
5732 want to warn about uses of EXPR as an integer, rather than
5733 as a pointer. */
5734 expr = build_int_cst (totype, 0);
5735 }
5736 return expr;
5737 case ck_ambig:
5738 /* We leave bad_p off ck_ambig because overload resolution considers
5739 it valid, it just fails when we try to perform it. So we need to
5740 check complain here, too. */
5741 if (complain & tf_error)
5742 {
5743 /* Call build_user_type_conversion again for the error. */
5744 build_user_type_conversion (totype, convs->u.expr, LOOKUP_NORMAL);
5745 if (fn)
5746 error (" initializing argument %P of %q+D", argnum, fn);
5747 }
5748 return error_mark_node;
5749
5750 case ck_list:
5751 {
5752 /* Conversion to std::initializer_list<T>. */
5753 tree elttype = TREE_VEC_ELT (CLASSTYPE_TI_ARGS (totype), 0);
5754 tree new_ctor = build_constructor (init_list_type_node, NULL);
5755 unsigned len = CONSTRUCTOR_NELTS (expr);
5756 tree array, val, field;
5757 VEC(constructor_elt,gc) *vec = NULL;
5758 unsigned ix;
5759
5760 /* Convert all the elements. */
5761 FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (expr), ix, val)
5762 {
5763 tree sub = convert_like_real (convs->u.list[ix], val, fn, argnum,
5764 1, false, false, complain);
5765 if (sub == error_mark_node)
5766 return sub;
5767 if (!BRACE_ENCLOSED_INITIALIZER_P (val))
5768 check_narrowing (TREE_TYPE (sub), val);
5769 CONSTRUCTOR_APPEND_ELT (CONSTRUCTOR_ELTS (new_ctor), NULL_TREE, sub);
5770 if (!TREE_CONSTANT (sub))
5771 TREE_CONSTANT (new_ctor) = false;
5772 }
5773 /* Build up the array. */
5774 elttype = cp_build_qualified_type
5775 (elttype, cp_type_quals (elttype) | TYPE_QUAL_CONST);
5776 array = build_array_of_n_type (elttype, len);
5777 array = finish_compound_literal (array, new_ctor, complain);
5778
5779 /* Build up the initializer_list object. */
5780 totype = complete_type (totype);
5781 field = next_initializable_field (TYPE_FIELDS (totype));
5782 CONSTRUCTOR_APPEND_ELT (vec, field, decay_conversion (array));
5783 field = next_initializable_field (DECL_CHAIN (field));
5784 CONSTRUCTOR_APPEND_ELT (vec, field, size_int (len));
5785 new_ctor = build_constructor (totype, vec);
5786 return get_target_expr (new_ctor);
5787 }
5788
5789 case ck_aggr:
5790 if (TREE_CODE (totype) == COMPLEX_TYPE)
5791 {
5792 tree real = CONSTRUCTOR_ELT (expr, 0)->value;
5793 tree imag = CONSTRUCTOR_ELT (expr, 1)->value;
5794 real = perform_implicit_conversion (TREE_TYPE (totype),
5795 real, complain);
5796 imag = perform_implicit_conversion (TREE_TYPE (totype),
5797 imag, complain);
5798 expr = build2 (COMPLEX_EXPR, totype, real, imag);
5799 return fold_if_not_in_template (expr);
5800 }
5801 return get_target_expr (digest_init (totype, expr, complain));
5802
5803 default:
5804 break;
5805 };
5806
5807 expr = convert_like_real (convs->u.next, expr, fn, argnum,
5808 convs->kind == ck_ref_bind ? -1 : 1,
5809 convs->kind == ck_ref_bind ? issue_conversion_warnings : false,
5810 c_cast_p,
5811 complain);
5812 if (expr == error_mark_node)
5813 return error_mark_node;
5814
5815 switch (convs->kind)
5816 {
5817 case ck_rvalue:
5818 expr = decay_conversion (expr);
5819 if (! MAYBE_CLASS_TYPE_P (totype))
5820 return expr;
5821 /* Else fall through. */
5822 case ck_base:
5823 if (convs->kind == ck_base && !convs->need_temporary_p)
5824 {
5825 /* We are going to bind a reference directly to a base-class
5826 subobject of EXPR. */
5827 /* Build an expression for `*((base*) &expr)'. */
5828 expr = cp_build_addr_expr (expr, complain);
5829 expr = convert_to_base (expr, build_pointer_type (totype),
5830 !c_cast_p, /*nonnull=*/true, complain);
5831 expr = cp_build_indirect_ref (expr, RO_IMPLICIT_CONVERSION, complain);
5832 return expr;
5833 }
5834
5835 /* Copy-initialization where the cv-unqualified version of the source
5836 type is the same class as, or a derived class of, the class of the
5837 destination [is treated as direct-initialization]. [dcl.init] */
5838 flags = LOOKUP_NORMAL|LOOKUP_ONLYCONVERTING;
5839 if (convs->user_conv_p)
5840 /* This conversion is being done in the context of a user-defined
5841 conversion (i.e. the second step of copy-initialization), so
5842 don't allow any more. */
5843 flags |= LOOKUP_NO_CONVERSION;
5844 if (convs->rvaluedness_matches_p)
5845 flags |= LOOKUP_PREFER_RVALUE;
5846 if (TREE_CODE (expr) == TARGET_EXPR
5847 && TARGET_EXPR_LIST_INIT_P (expr))
5848 /* Copy-list-initialization doesn't actually involve a copy. */
5849 return expr;
5850 expr = build_temp (expr, totype, flags, &diag_kind, complain);
5851 if (diag_kind && fn && complain)
5852 emit_diagnostic (diag_kind, DECL_SOURCE_LOCATION (fn), 0,
5853 " initializing argument %P of %qD", argnum, fn);
5854 return build_cplus_new (totype, expr, complain);
5855
5856 case ck_ref_bind:
5857 {
5858 tree ref_type = totype;
5859
5860 if (convs->bad_p && !convs->u.next->bad_p)
5861 {
5862 gcc_assert (TYPE_REF_IS_RVALUE (ref_type)
5863 && real_lvalue_p (expr));
5864
5865 error ("cannot bind %qT lvalue to %qT",
5866 TREE_TYPE (expr), totype);
5867 if (fn)
5868 error (" initializing argument %P of %q+D", argnum, fn);
5869 return error_mark_node;
5870 }
5871
5872 /* If necessary, create a temporary.
5873
5874 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
5875 that need temporaries, even when their types are reference
5876 compatible with the type of reference being bound, so the
5877 upcoming call to cp_build_addr_expr doesn't fail. */
5878 if (convs->need_temporary_p
5879 || TREE_CODE (expr) == CONSTRUCTOR
5880 || TREE_CODE (expr) == VA_ARG_EXPR)
5881 {
5882 /* Otherwise, a temporary of type "cv1 T1" is created and
5883 initialized from the initializer expression using the rules
5884 for a non-reference copy-initialization (8.5). */
5885
5886 tree type = TREE_TYPE (ref_type);
5887 cp_lvalue_kind lvalue = real_lvalue_p (expr);
5888
5889 gcc_assert (same_type_ignoring_top_level_qualifiers_p
5890 (type, convs->u.next->type));
5891 if (!CP_TYPE_CONST_NON_VOLATILE_P (type)
5892 && !TYPE_REF_IS_RVALUE (ref_type))
5893 {
5894 /* If the reference is volatile or non-const, we
5895 cannot create a temporary. */
5896 if (lvalue & clk_bitfield)
5897 error ("cannot bind bitfield %qE to %qT",
5898 expr, ref_type);
5899 else if (lvalue & clk_packed)
5900 error ("cannot bind packed field %qE to %qT",
5901 expr, ref_type);
5902 else
5903 error ("cannot bind rvalue %qE to %qT", expr, ref_type);
5904 return error_mark_node;
5905 }
5906 /* If the source is a packed field, and we must use a copy
5907 constructor, then building the target expr will require
5908 binding the field to the reference parameter to the
5909 copy constructor, and we'll end up with an infinite
5910 loop. If we can use a bitwise copy, then we'll be
5911 OK. */
5912 if ((lvalue & clk_packed)
5913 && CLASS_TYPE_P (type)
5914 && type_has_nontrivial_copy_init (type))
5915 {
5916 error ("cannot bind packed field %qE to %qT",
5917 expr, ref_type);
5918 return error_mark_node;
5919 }
5920 if (lvalue & clk_bitfield)
5921 {
5922 expr = convert_bitfield_to_declared_type (expr);
5923 expr = fold_convert (type, expr);
5924 }
5925 expr = build_target_expr_with_type (expr, type, complain);
5926 }
5927
5928 /* Take the address of the thing to which we will bind the
5929 reference. */
5930 expr = cp_build_addr_expr (expr, complain);
5931 if (expr == error_mark_node)
5932 return error_mark_node;
5933
5934 /* Convert it to a pointer to the type referred to by the
5935 reference. This will adjust the pointer if a derived to
5936 base conversion is being performed. */
5937 expr = cp_convert (build_pointer_type (TREE_TYPE (ref_type)),
5938 expr);
5939 /* Convert the pointer to the desired reference type. */
5940 return build_nop (ref_type, expr);
5941 }
5942
5943 case ck_lvalue:
5944 return decay_conversion (expr);
5945
5946 case ck_qual:
5947 /* Warn about deprecated conversion if appropriate. */
5948 string_conv_p (totype, expr, 1);
5949 break;
5950
5951 case ck_ptr:
5952 if (convs->base_p)
5953 expr = convert_to_base (expr, totype, !c_cast_p,
5954 /*nonnull=*/false, complain);
5955 return build_nop (totype, expr);
5956
5957 case ck_pmem:
5958 return convert_ptrmem (totype, expr, /*allow_inverse_p=*/false,
5959 c_cast_p, complain);
5960
5961 default:
5962 break;
5963 }
5964
5965 if (convs->check_narrowing)
5966 check_narrowing (totype, expr);
5967
5968 if (issue_conversion_warnings && (complain & tf_warning))
5969 expr = convert_and_check (totype, expr);
5970 else
5971 expr = convert (totype, expr);
5972
5973 return expr;
5974 }
5975
5976 /* ARG is being passed to a varargs function. Perform any conversions
5977 required. Return the converted value. */
5978
5979 tree
5980 convert_arg_to_ellipsis (tree arg)
5981 {
5982 tree arg_type;
5983
5984 /* [expr.call]
5985
5986 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5987 standard conversions are performed. */
5988 arg = decay_conversion (arg);
5989 arg_type = TREE_TYPE (arg);
5990 /* [expr.call]
5991
5992 If the argument has integral or enumeration type that is subject
5993 to the integral promotions (_conv.prom_), or a floating point
5994 type that is subject to the floating point promotion
5995 (_conv.fpprom_), the value of the argument is converted to the
5996 promoted type before the call. */
5997 if (TREE_CODE (arg_type) == REAL_TYPE
5998 && (TYPE_PRECISION (arg_type)
5999 < TYPE_PRECISION (double_type_node))
6000 && !DECIMAL_FLOAT_MODE_P (TYPE_MODE (arg_type)))
6001 {
6002 if (warn_double_promotion && !c_inhibit_evaluation_warnings)
6003 warning (OPT_Wdouble_promotion,
6004 "implicit conversion from %qT to %qT when passing "
6005 "argument to function",
6006 arg_type, double_type_node);
6007 arg = convert_to_real (double_type_node, arg);
6008 }
6009 else if (NULLPTR_TYPE_P (arg_type))
6010 arg = null_pointer_node;
6011 else if (INTEGRAL_OR_ENUMERATION_TYPE_P (arg_type))
6012 {
6013 if (SCOPED_ENUM_P (arg_type) && !abi_version_at_least (6))
6014 {
6015 warning (OPT_Wabi, "scoped enum %qT will not promote to an "
6016 "integral type in a future version of GCC", arg_type);
6017 arg = cp_convert (ENUM_UNDERLYING_TYPE (arg_type), arg);
6018 }
6019 arg = perform_integral_promotions (arg);
6020 }
6021
6022 arg = require_complete_type (arg);
6023 arg_type = TREE_TYPE (arg);
6024
6025 if (arg != error_mark_node
6026 /* In a template (or ill-formed code), we can have an incomplete type
6027 even after require_complete_type, in which case we don't know
6028 whether it has trivial copy or not. */
6029 && COMPLETE_TYPE_P (arg_type))
6030 {
6031 /* Build up a real lvalue-to-rvalue conversion in case the
6032 copy constructor is trivial but not callable. */
6033 if (!cp_unevaluated_operand && CLASS_TYPE_P (arg_type))
6034 force_rvalue (arg, tf_warning_or_error);
6035
6036 /* [expr.call] 5.2.2/7:
6037 Passing a potentially-evaluated argument of class type (Clause 9)
6038 with a non-trivial copy constructor or a non-trivial destructor
6039 with no corresponding parameter is conditionally-supported, with
6040 implementation-defined semantics.
6041
6042 We used to just warn here and do a bitwise copy, but now
6043 cp_expr_size will abort if we try to do that.
6044
6045 If the call appears in the context of a sizeof expression,
6046 it is not potentially-evaluated. */
6047 if (cp_unevaluated_operand == 0
6048 && (type_has_nontrivial_copy_init (arg_type)
6049 || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (arg_type)))
6050 error ("cannot pass objects of non-trivially-copyable "
6051 "type %q#T through %<...%>", arg_type);
6052 }
6053
6054 return arg;
6055 }
6056
6057 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6058
6059 tree
6060 build_x_va_arg (tree expr, tree type)
6061 {
6062 if (processing_template_decl)
6063 return build_min (VA_ARG_EXPR, type, expr);
6064
6065 type = complete_type_or_else (type, NULL_TREE);
6066
6067 if (expr == error_mark_node || !type)
6068 return error_mark_node;
6069
6070 expr = mark_lvalue_use (expr);
6071
6072 if (type_has_nontrivial_copy_init (type)
6073 || TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type)
6074 || TREE_CODE (type) == REFERENCE_TYPE)
6075 {
6076 /* Remove reference types so we don't ICE later on. */
6077 tree type1 = non_reference (type);
6078 /* conditionally-supported behavior [expr.call] 5.2.2/7. */
6079 error ("cannot receive objects of non-trivially-copyable type %q#T "
6080 "through %<...%>; ", type);
6081 expr = convert (build_pointer_type (type1), null_node);
6082 expr = cp_build_indirect_ref (expr, RO_NULL, tf_warning_or_error);
6083 return expr;
6084 }
6085
6086 return build_va_arg (input_location, expr, type);
6087 }
6088
6089 /* TYPE has been given to va_arg. Apply the default conversions which
6090 would have happened when passed via ellipsis. Return the promoted
6091 type, or the passed type if there is no change. */
6092
6093 tree
6094 cxx_type_promotes_to (tree type)
6095 {
6096 tree promote;
6097
6098 /* Perform the array-to-pointer and function-to-pointer
6099 conversions. */
6100 type = type_decays_to (type);
6101
6102 promote = type_promotes_to (type);
6103 if (same_type_p (type, promote))
6104 promote = type;
6105
6106 return promote;
6107 }
6108
6109 /* ARG is a default argument expression being passed to a parameter of
6110 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6111 zero-based argument number. Do any required conversions. Return
6112 the converted value. */
6113
6114 static GTY(()) VEC(tree,gc) *default_arg_context;
6115 void
6116 push_defarg_context (tree fn)
6117 { VEC_safe_push (tree, gc, default_arg_context, fn); }
6118 void
6119 pop_defarg_context (void)
6120 { VEC_pop (tree, default_arg_context); }
6121
6122 tree
6123 convert_default_arg (tree type, tree arg, tree fn, int parmnum)
6124 {
6125 int i;
6126 tree t;
6127
6128 /* See through clones. */
6129 fn = DECL_ORIGIN (fn);
6130
6131 /* Detect recursion. */
6132 FOR_EACH_VEC_ELT (tree, default_arg_context, i, t)
6133 if (t == fn)
6134 {
6135 error ("recursive evaluation of default argument for %q#D", fn);
6136 return error_mark_node;
6137 }
6138
6139 /* If the ARG is an unparsed default argument expression, the
6140 conversion cannot be performed. */
6141 if (TREE_CODE (arg) == DEFAULT_ARG)
6142 {
6143 error ("call to %qD uses the default argument for parameter %P, which "
6144 "is not yet defined", fn, parmnum);
6145 return error_mark_node;
6146 }
6147
6148 push_defarg_context (fn);
6149
6150 if (fn && DECL_TEMPLATE_INFO (fn))
6151 arg = tsubst_default_argument (fn, type, arg);
6152
6153 /* Due to:
6154
6155 [dcl.fct.default]
6156
6157 The names in the expression are bound, and the semantic
6158 constraints are checked, at the point where the default
6159 expressions appears.
6160
6161 we must not perform access checks here. */
6162 push_deferring_access_checks (dk_no_check);
6163 /* We must make a copy of ARG, in case subsequent processing
6164 alters any part of it. */
6165 arg = break_out_target_exprs (arg);
6166 if (TREE_CODE (arg) == CONSTRUCTOR)
6167 {
6168 arg = digest_init (type, arg, tf_warning_or_error);
6169 arg = convert_for_initialization (0, type, arg, LOOKUP_IMPLICIT,
6170 ICR_DEFAULT_ARGUMENT, fn, parmnum,
6171 tf_warning_or_error);
6172 }
6173 else
6174 {
6175 arg = convert_for_initialization (0, type, arg, LOOKUP_IMPLICIT,
6176 ICR_DEFAULT_ARGUMENT, fn, parmnum,
6177 tf_warning_or_error);
6178 arg = convert_for_arg_passing (type, arg);
6179 }
6180 pop_deferring_access_checks();
6181
6182 pop_defarg_context ();
6183
6184 return arg;
6185 }
6186
6187 /* Returns the type which will really be used for passing an argument of
6188 type TYPE. */
6189
6190 tree
6191 type_passed_as (tree type)
6192 {
6193 /* Pass classes with copy ctors by invisible reference. */
6194 if (TREE_ADDRESSABLE (type))
6195 {
6196 type = build_reference_type (type);
6197 /* There are no other pointers to this temporary. */
6198 type = cp_build_qualified_type (type, TYPE_QUAL_RESTRICT);
6199 }
6200 else if (targetm.calls.promote_prototypes (type)
6201 && INTEGRAL_TYPE_P (type)
6202 && COMPLETE_TYPE_P (type)
6203 && INT_CST_LT_UNSIGNED (TYPE_SIZE (type),
6204 TYPE_SIZE (integer_type_node)))
6205 type = integer_type_node;
6206
6207 return type;
6208 }
6209
6210 /* Actually perform the appropriate conversion. */
6211
6212 tree
6213 convert_for_arg_passing (tree type, tree val)
6214 {
6215 tree bitfield_type;
6216
6217 /* If VAL is a bitfield, then -- since it has already been converted
6218 to TYPE -- it cannot have a precision greater than TYPE.
6219
6220 If it has a smaller precision, we must widen it here. For
6221 example, passing "int f:3;" to a function expecting an "int" will
6222 not result in any conversion before this point.
6223
6224 If the precision is the same we must not risk widening. For
6225 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6226 often have type "int", even though the C++ type for the field is
6227 "long long". If the value is being passed to a function
6228 expecting an "int", then no conversions will be required. But,
6229 if we call convert_bitfield_to_declared_type, the bitfield will
6230 be converted to "long long". */
6231 bitfield_type = is_bitfield_expr_with_lowered_type (val);
6232 if (bitfield_type
6233 && TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type))
6234 val = convert_to_integer (TYPE_MAIN_VARIANT (bitfield_type), val);
6235
6236 if (val == error_mark_node)
6237 ;
6238 /* Pass classes with copy ctors by invisible reference. */
6239 else if (TREE_ADDRESSABLE (type))
6240 val = build1 (ADDR_EXPR, build_reference_type (type), val);
6241 else if (targetm.calls.promote_prototypes (type)
6242 && INTEGRAL_TYPE_P (type)
6243 && COMPLETE_TYPE_P (type)
6244 && INT_CST_LT_UNSIGNED (TYPE_SIZE (type),
6245 TYPE_SIZE (integer_type_node)))
6246 val = perform_integral_promotions (val);
6247 if (warn_missing_format_attribute)
6248 {
6249 tree rhstype = TREE_TYPE (val);
6250 const enum tree_code coder = TREE_CODE (rhstype);
6251 const enum tree_code codel = TREE_CODE (type);
6252 if ((codel == POINTER_TYPE || codel == REFERENCE_TYPE)
6253 && coder == codel
6254 && check_missing_format_attribute (type, rhstype))
6255 warning (OPT_Wmissing_format_attribute,
6256 "argument of function call might be a candidate for a format attribute");
6257 }
6258 return val;
6259 }
6260
6261 /* Returns true iff FN is a function with magic varargs, i.e. ones for
6262 which no conversions at all should be done. This is true for some
6263 builtins which don't act like normal functions. */
6264
6265 static bool
6266 magic_varargs_p (tree fn)
6267 {
6268 if (DECL_BUILT_IN (fn))
6269 switch (DECL_FUNCTION_CODE (fn))
6270 {
6271 case BUILT_IN_CLASSIFY_TYPE:
6272 case BUILT_IN_CONSTANT_P:
6273 case BUILT_IN_NEXT_ARG:
6274 case BUILT_IN_VA_START:
6275 return true;
6276
6277 default:;
6278 return lookup_attribute ("type generic",
6279 TYPE_ATTRIBUTES (TREE_TYPE (fn))) != 0;
6280 }
6281
6282 return false;
6283 }
6284
6285 /* Subroutine of the various build_*_call functions. Overload resolution
6286 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
6287 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
6288 bitmask of various LOOKUP_* flags which apply to the call itself. */
6289
6290 static tree
6291 build_over_call (struct z_candidate *cand, int flags, tsubst_flags_t complain)
6292 {
6293 tree fn = cand->fn;
6294 const VEC(tree,gc) *args = cand->args;
6295 tree first_arg = cand->first_arg;
6296 conversion **convs = cand->convs;
6297 conversion *conv;
6298 tree parm = TYPE_ARG_TYPES (TREE_TYPE (fn));
6299 int parmlen;
6300 tree val;
6301 int i = 0;
6302 int j = 0;
6303 unsigned int arg_index = 0;
6304 int is_method = 0;
6305 int nargs;
6306 tree *argarray;
6307 bool already_used = false;
6308
6309 /* In a template, there is no need to perform all of the work that
6310 is normally done. We are only interested in the type of the call
6311 expression, i.e., the return type of the function. Any semantic
6312 errors will be deferred until the template is instantiated. */
6313 if (processing_template_decl)
6314 {
6315 tree expr;
6316 tree return_type;
6317 const tree *argarray;
6318 unsigned int nargs;
6319
6320 return_type = TREE_TYPE (TREE_TYPE (fn));
6321 nargs = VEC_length (tree, args);
6322 if (first_arg == NULL_TREE)
6323 argarray = VEC_address (tree, CONST_CAST (VEC(tree,gc) *, args));
6324 else
6325 {
6326 tree *alcarray;
6327 unsigned int ix;
6328 tree arg;
6329
6330 ++nargs;
6331 alcarray = XALLOCAVEC (tree, nargs);
6332 alcarray[0] = first_arg;
6333 FOR_EACH_VEC_ELT (tree, args, ix, arg)
6334 alcarray[ix + 1] = arg;
6335 argarray = alcarray;
6336 }
6337 expr = build_call_array_loc (input_location,
6338 return_type, build_addr_func (fn), nargs,
6339 argarray);
6340 if (TREE_THIS_VOLATILE (fn) && cfun)
6341 current_function_returns_abnormally = 1;
6342 return convert_from_reference (expr);
6343 }
6344
6345 /* Give any warnings we noticed during overload resolution. */
6346 if (cand->warnings && (complain & tf_warning))
6347 {
6348 struct candidate_warning *w;
6349 for (w = cand->warnings; w; w = w->next)
6350 joust (cand, w->loser, 1);
6351 }
6352
6353 /* Make =delete work with SFINAE. */
6354 if (DECL_DELETED_FN (fn) && !(complain & tf_error))
6355 return error_mark_node;
6356
6357 if (DECL_FUNCTION_MEMBER_P (fn))
6358 {
6359 tree access_fn;
6360 /* If FN is a template function, two cases must be considered.
6361 For example:
6362
6363 struct A {
6364 protected:
6365 template <class T> void f();
6366 };
6367 template <class T> struct B {
6368 protected:
6369 void g();
6370 };
6371 struct C : A, B<int> {
6372 using A::f; // #1
6373 using B<int>::g; // #2
6374 };
6375
6376 In case #1 where `A::f' is a member template, DECL_ACCESS is
6377 recorded in the primary template but not in its specialization.
6378 We check access of FN using its primary template.
6379
6380 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
6381 because it is a member of class template B, DECL_ACCESS is
6382 recorded in the specialization `B<int>::g'. We cannot use its
6383 primary template because `B<T>::g' and `B<int>::g' may have
6384 different access. */
6385 if (DECL_TEMPLATE_INFO (fn)
6386 && DECL_MEMBER_TEMPLATE_P (DECL_TI_TEMPLATE (fn)))
6387 access_fn = DECL_TI_TEMPLATE (fn);
6388 else
6389 access_fn = fn;
6390 if (flags & LOOKUP_SPECULATIVE)
6391 {
6392 if (!speculative_access_check (cand->access_path, access_fn, fn,
6393 !!(flags & LOOKUP_COMPLAIN)))
6394 return error_mark_node;
6395 }
6396 else
6397 perform_or_defer_access_check (cand->access_path, access_fn, fn);
6398 }
6399
6400 /* If we're checking for implicit delete, don't bother with argument
6401 conversions. */
6402 if (flags & LOOKUP_SPECULATIVE)
6403 {
6404 if (DECL_DELETED_FN (fn))
6405 {
6406 if (flags & LOOKUP_COMPLAIN)
6407 mark_used (fn);
6408 return error_mark_node;
6409 }
6410 if (cand->viable == 1)
6411 return fn;
6412 else if (!(flags & LOOKUP_COMPLAIN))
6413 /* Reject bad conversions now. */
6414 return error_mark_node;
6415 /* else continue to get conversion error. */
6416 }
6417
6418 /* Find maximum size of vector to hold converted arguments. */
6419 parmlen = list_length (parm);
6420 nargs = VEC_length (tree, args) + (first_arg != NULL_TREE ? 1 : 0);
6421 if (parmlen > nargs)
6422 nargs = parmlen;
6423 argarray = XALLOCAVEC (tree, nargs);
6424
6425 /* The implicit parameters to a constructor are not considered by overload
6426 resolution, and must be of the proper type. */
6427 if (DECL_CONSTRUCTOR_P (fn))
6428 {
6429 if (first_arg != NULL_TREE)
6430 {
6431 argarray[j++] = first_arg;
6432 first_arg = NULL_TREE;
6433 }
6434 else
6435 {
6436 argarray[j++] = VEC_index (tree, args, arg_index);
6437 ++arg_index;
6438 }
6439 parm = TREE_CHAIN (parm);
6440 /* We should never try to call the abstract constructor. */
6441 gcc_assert (!DECL_HAS_IN_CHARGE_PARM_P (fn));
6442
6443 if (DECL_HAS_VTT_PARM_P (fn))
6444 {
6445 argarray[j++] = VEC_index (tree, args, arg_index);
6446 ++arg_index;
6447 parm = TREE_CHAIN (parm);
6448 }
6449 }
6450 /* Bypass access control for 'this' parameter. */
6451 else if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE)
6452 {
6453 tree parmtype = TREE_VALUE (parm);
6454 tree arg = (first_arg != NULL_TREE
6455 ? first_arg
6456 : VEC_index (tree, args, arg_index));
6457 tree argtype = TREE_TYPE (arg);
6458 tree converted_arg;
6459 tree base_binfo;
6460
6461 if (convs[i]->bad_p)
6462 {
6463 if (complain & tf_error)
6464 permerror (input_location, "passing %qT as %<this%> argument of %q#D discards qualifiers",
6465 TREE_TYPE (argtype), fn);
6466 else
6467 return error_mark_node;
6468 }
6469
6470 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
6471 X is called for an object that is not of type X, or of a type
6472 derived from X, the behavior is undefined.
6473
6474 So we can assume that anything passed as 'this' is non-null, and
6475 optimize accordingly. */
6476 gcc_assert (TREE_CODE (parmtype) == POINTER_TYPE);
6477 /* Convert to the base in which the function was declared. */
6478 gcc_assert (cand->conversion_path != NULL_TREE);
6479 converted_arg = build_base_path (PLUS_EXPR,
6480 arg,
6481 cand->conversion_path,
6482 1, complain);
6483 /* Check that the base class is accessible. */
6484 if (!accessible_base_p (TREE_TYPE (argtype),
6485 BINFO_TYPE (cand->conversion_path), true))
6486 error ("%qT is not an accessible base of %qT",
6487 BINFO_TYPE (cand->conversion_path),
6488 TREE_TYPE (argtype));
6489 /* If fn was found by a using declaration, the conversion path
6490 will be to the derived class, not the base declaring fn. We
6491 must convert from derived to base. */
6492 base_binfo = lookup_base (TREE_TYPE (TREE_TYPE (converted_arg)),
6493 TREE_TYPE (parmtype), ba_unique, NULL);
6494 converted_arg = build_base_path (PLUS_EXPR, converted_arg,
6495 base_binfo, 1, complain);
6496
6497 argarray[j++] = converted_arg;
6498 parm = TREE_CHAIN (parm);
6499 if (first_arg != NULL_TREE)
6500 first_arg = NULL_TREE;
6501 else
6502 ++arg_index;
6503 ++i;
6504 is_method = 1;
6505 }
6506
6507 gcc_assert (first_arg == NULL_TREE);
6508 for (; arg_index < VEC_length (tree, args) && parm;
6509 parm = TREE_CHAIN (parm), ++arg_index, ++i)
6510 {
6511 tree type = TREE_VALUE (parm);
6512 tree arg = VEC_index (tree, args, arg_index);
6513 bool conversion_warning = true;
6514
6515 conv = convs[i];
6516
6517 /* If the argument is NULL and used to (implicitly) instantiate a
6518 template function (and bind one of the template arguments to
6519 the type of 'long int'), we don't want to warn about passing NULL
6520 to non-pointer argument.
6521 For example, if we have this template function:
6522
6523 template<typename T> void func(T x) {}
6524
6525 we want to warn (when -Wconversion is enabled) in this case:
6526
6527 void foo() {
6528 func<int>(NULL);
6529 }
6530
6531 but not in this case:
6532
6533 void foo() {
6534 func(NULL);
6535 }
6536 */
6537 if (arg == null_node
6538 && DECL_TEMPLATE_INFO (fn)
6539 && cand->template_decl
6540 && !(flags & LOOKUP_EXPLICIT_TMPL_ARGS))
6541 conversion_warning = false;
6542
6543 /* Warn about initializer_list deduction that isn't currently in the
6544 working draft. */
6545 if (cxx_dialect > cxx98
6546 && flag_deduce_init_list
6547 && cand->template_decl
6548 && is_std_init_list (non_reference (type))
6549 && BRACE_ENCLOSED_INITIALIZER_P (arg))
6550 {
6551 tree tmpl = TI_TEMPLATE (cand->template_decl);
6552 tree realparm = chain_index (j, DECL_ARGUMENTS (cand->fn));
6553 tree patparm = get_pattern_parm (realparm, tmpl);
6554 tree pattype = TREE_TYPE (patparm);
6555 if (PACK_EXPANSION_P (pattype))
6556 pattype = PACK_EXPANSION_PATTERN (pattype);
6557 pattype = non_reference (pattype);
6558
6559 if (TREE_CODE (pattype) == TEMPLATE_TYPE_PARM
6560 && (cand->explicit_targs == NULL_TREE
6561 || (TREE_VEC_LENGTH (cand->explicit_targs)
6562 <= TEMPLATE_TYPE_IDX (pattype))))
6563 {
6564 pedwarn (input_location, 0, "deducing %qT as %qT",
6565 non_reference (TREE_TYPE (patparm)),
6566 non_reference (type));
6567 pedwarn (input_location, 0, " in call to %q+D", cand->fn);
6568 pedwarn (input_location, 0,
6569 " (you can disable this with -fno-deduce-init-list)");
6570 }
6571 }
6572
6573 val = convert_like_with_context (conv, arg, fn, i-is_method,
6574 conversion_warning
6575 ? complain
6576 : complain & (~tf_warning));
6577
6578 val = convert_for_arg_passing (type, val);
6579 if (val == error_mark_node)
6580 return error_mark_node;
6581 else
6582 argarray[j++] = val;
6583 }
6584
6585 /* Default arguments */
6586 for (; parm && parm != void_list_node; parm = TREE_CHAIN (parm), i++)
6587 argarray[j++] = convert_default_arg (TREE_VALUE (parm),
6588 TREE_PURPOSE (parm),
6589 fn, i - is_method);
6590 /* Ellipsis */
6591 for (; arg_index < VEC_length (tree, args); ++arg_index)
6592 {
6593 tree a = VEC_index (tree, args, arg_index);
6594 if (magic_varargs_p (fn))
6595 /* Do no conversions for magic varargs. */
6596 a = mark_type_use (a);
6597 else
6598 a = convert_arg_to_ellipsis (a);
6599 argarray[j++] = a;
6600 }
6601
6602 gcc_assert (j <= nargs);
6603 nargs = j;
6604
6605 check_function_arguments (TREE_TYPE (fn), nargs, argarray);
6606
6607 /* Avoid actually calling copy constructors and copy assignment operators,
6608 if possible. */
6609
6610 if (! flag_elide_constructors)
6611 /* Do things the hard way. */;
6612 else if (cand->num_convs == 1
6613 && (DECL_COPY_CONSTRUCTOR_P (fn)
6614 || DECL_MOVE_CONSTRUCTOR_P (fn)))
6615 {
6616 tree targ;
6617 tree arg = argarray[num_artificial_parms_for (fn)];
6618 tree fa;
6619 bool trivial = trivial_fn_p (fn);
6620
6621 /* Pull out the real argument, disregarding const-correctness. */
6622 targ = arg;
6623 while (CONVERT_EXPR_P (targ)
6624 || TREE_CODE (targ) == NON_LVALUE_EXPR)
6625 targ = TREE_OPERAND (targ, 0);
6626 if (TREE_CODE (targ) == ADDR_EXPR)
6627 {
6628 targ = TREE_OPERAND (targ, 0);
6629 if (!same_type_ignoring_top_level_qualifiers_p
6630 (TREE_TYPE (TREE_TYPE (arg)), TREE_TYPE (targ)))
6631 targ = NULL_TREE;
6632 }
6633 else
6634 targ = NULL_TREE;
6635
6636 if (targ)
6637 arg = targ;
6638 else
6639 arg = cp_build_indirect_ref (arg, RO_NULL, complain);
6640
6641 /* [class.copy]: the copy constructor is implicitly defined even if
6642 the implementation elided its use. */
6643 if (!trivial || DECL_DELETED_FN (fn))
6644 {
6645 mark_used (fn);
6646 already_used = true;
6647 }
6648
6649 /* If we're creating a temp and we already have one, don't create a
6650 new one. If we're not creating a temp but we get one, use
6651 INIT_EXPR to collapse the temp into our target. Otherwise, if the
6652 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
6653 temp or an INIT_EXPR otherwise. */
6654 fa = argarray[0];
6655 if (integer_zerop (fa))
6656 {
6657 if (TREE_CODE (arg) == TARGET_EXPR)
6658 return arg;
6659 else if (trivial)
6660 return force_target_expr (DECL_CONTEXT (fn), arg, complain);
6661 }
6662 else if (TREE_CODE (arg) == TARGET_EXPR || trivial)
6663 {
6664 tree to = stabilize_reference (cp_build_indirect_ref (fa, RO_NULL,
6665 complain));
6666
6667 val = build2 (INIT_EXPR, DECL_CONTEXT (fn), to, arg);
6668 return val;
6669 }
6670 }
6671 else if (DECL_OVERLOADED_OPERATOR_P (fn) == NOP_EXPR
6672 && trivial_fn_p (fn)
6673 && !DECL_DELETED_FN (fn))
6674 {
6675 tree to = stabilize_reference
6676 (cp_build_indirect_ref (argarray[0], RO_NULL, complain));
6677 tree type = TREE_TYPE (to);
6678 tree as_base = CLASSTYPE_AS_BASE (type);
6679 tree arg = argarray[1];
6680
6681 if (is_really_empty_class (type))
6682 {
6683 /* Avoid copying empty classes. */
6684 val = build2 (COMPOUND_EXPR, void_type_node, to, arg);
6685 TREE_NO_WARNING (val) = 1;
6686 val = build2 (COMPOUND_EXPR, type, val, to);
6687 TREE_NO_WARNING (val) = 1;
6688 }
6689 else if (tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (as_base)))
6690 {
6691 arg = cp_build_indirect_ref (arg, RO_NULL, complain);
6692 val = build2 (MODIFY_EXPR, TREE_TYPE (to), to, arg);
6693 }
6694 else
6695 {
6696 /* We must only copy the non-tail padding parts. */
6697 tree arg0, arg2, t;
6698 tree array_type, alias_set;
6699
6700 arg2 = TYPE_SIZE_UNIT (as_base);
6701 arg0 = cp_build_addr_expr (to, complain);
6702
6703 array_type = build_array_type (char_type_node,
6704 build_index_type
6705 (size_binop (MINUS_EXPR,
6706 arg2, size_int (1))));
6707 alias_set = build_int_cst (build_pointer_type (type), 0);
6708 t = build2 (MODIFY_EXPR, void_type_node,
6709 build2 (MEM_REF, array_type, arg0, alias_set),
6710 build2 (MEM_REF, array_type, arg, alias_set));
6711 val = build2 (COMPOUND_EXPR, TREE_TYPE (to), t, to);
6712 TREE_NO_WARNING (val) = 1;
6713 }
6714
6715 return val;
6716 }
6717 else if (DECL_DESTRUCTOR_P (fn)
6718 && trivial_fn_p (fn)
6719 && !DECL_DELETED_FN (fn))
6720 return fold_convert (void_type_node, argarray[0]);
6721 /* FIXME handle trivial default constructor, too. */
6722
6723 if (!already_used)
6724 mark_used (fn);
6725
6726 if (DECL_VINDEX (fn) && (flags & LOOKUP_NONVIRTUAL) == 0)
6727 {
6728 tree t;
6729 tree binfo = lookup_base (TREE_TYPE (TREE_TYPE (argarray[0])),
6730 DECL_CONTEXT (fn),
6731 ba_any, NULL);
6732 gcc_assert (binfo && binfo != error_mark_node);
6733
6734 /* Warn about deprecated virtual functions now, since we're about
6735 to throw away the decl. */
6736 if (TREE_DEPRECATED (fn))
6737 warn_deprecated_use (fn, NULL_TREE);
6738
6739 argarray[0] = build_base_path (PLUS_EXPR, argarray[0], binfo, 1,
6740 complain);
6741 if (TREE_SIDE_EFFECTS (argarray[0]))
6742 argarray[0] = save_expr (argarray[0]);
6743 t = build_pointer_type (TREE_TYPE (fn));
6744 if (DECL_CONTEXT (fn) && TYPE_JAVA_INTERFACE (DECL_CONTEXT (fn)))
6745 fn = build_java_interface_fn_ref (fn, argarray[0]);
6746 else
6747 fn = build_vfn_ref (argarray[0], DECL_VINDEX (fn));
6748 TREE_TYPE (fn) = t;
6749 }
6750 else
6751 fn = build_addr_func (fn);
6752
6753 return build_cxx_call (fn, nargs, argarray);
6754 }
6755
6756 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
6757 This function performs no overload resolution, conversion, or other
6758 high-level operations. */
6759
6760 tree
6761 build_cxx_call (tree fn, int nargs, tree *argarray)
6762 {
6763 tree fndecl;
6764
6765 /* Remember roughly where this call is. */
6766 location_t loc = EXPR_LOC_OR_HERE (fn);
6767 fn = build_call_a (fn, nargs, argarray);
6768 SET_EXPR_LOCATION (fn, loc);
6769
6770 fndecl = get_callee_fndecl (fn);
6771
6772 /* Check that arguments to builtin functions match the expectations. */
6773 if (fndecl
6774 && DECL_BUILT_IN (fndecl)
6775 && DECL_BUILT_IN_CLASS (fndecl) == BUILT_IN_NORMAL
6776 && !check_builtin_function_arguments (fndecl, nargs, argarray))
6777 return error_mark_node;
6778
6779 /* Some built-in function calls will be evaluated at compile-time in
6780 fold (). */
6781 fn = fold_if_not_in_template (fn);
6782
6783 if (VOID_TYPE_P (TREE_TYPE (fn)))
6784 return fn;
6785
6786 fn = require_complete_type (fn);
6787 if (fn == error_mark_node)
6788 return error_mark_node;
6789
6790 if (MAYBE_CLASS_TYPE_P (TREE_TYPE (fn)))
6791 fn = build_cplus_new (TREE_TYPE (fn), fn, tf_warning_or_error);
6792 return convert_from_reference (fn);
6793 }
6794
6795 static GTY(()) tree java_iface_lookup_fn;
6796
6797 /* Make an expression which yields the address of the Java interface
6798 method FN. This is achieved by generating a call to libjava's
6799 _Jv_LookupInterfaceMethodIdx(). */
6800
6801 static tree
6802 build_java_interface_fn_ref (tree fn, tree instance)
6803 {
6804 tree lookup_fn, method, idx;
6805 tree klass_ref, iface, iface_ref;
6806 int i;
6807
6808 if (!java_iface_lookup_fn)
6809 {
6810 tree ftype = build_function_type_list (ptr_type_node,
6811 ptr_type_node, ptr_type_node,
6812 java_int_type_node, NULL_TREE);
6813 java_iface_lookup_fn
6814 = add_builtin_function ("_Jv_LookupInterfaceMethodIdx", ftype,
6815 0, NOT_BUILT_IN, NULL, NULL_TREE);
6816 }
6817
6818 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
6819 This is the first entry in the vtable. */
6820 klass_ref = build_vtbl_ref (cp_build_indirect_ref (instance, RO_NULL,
6821 tf_warning_or_error),
6822 integer_zero_node);
6823
6824 /* Get the java.lang.Class pointer for the interface being called. */
6825 iface = DECL_CONTEXT (fn);
6826 iface_ref = lookup_field (iface, get_identifier ("class$"), 0, false);
6827 if (!iface_ref || TREE_CODE (iface_ref) != VAR_DECL
6828 || DECL_CONTEXT (iface_ref) != iface)
6829 {
6830 error ("could not find class$ field in java interface type %qT",
6831 iface);
6832 return error_mark_node;
6833 }
6834 iface_ref = build_address (iface_ref);
6835 iface_ref = convert (build_pointer_type (iface), iface_ref);
6836
6837 /* Determine the itable index of FN. */
6838 i = 1;
6839 for (method = TYPE_METHODS (iface); method; method = DECL_CHAIN (method))
6840 {
6841 if (!DECL_VIRTUAL_P (method))
6842 continue;
6843 if (fn == method)
6844 break;
6845 i++;
6846 }
6847 idx = build_int_cst (NULL_TREE, i);
6848
6849 lookup_fn = build1 (ADDR_EXPR,
6850 build_pointer_type (TREE_TYPE (java_iface_lookup_fn)),
6851 java_iface_lookup_fn);
6852 return build_call_nary (ptr_type_node, lookup_fn,
6853 3, klass_ref, iface_ref, idx);
6854 }
6855
6856 /* Returns the value to use for the in-charge parameter when making a
6857 call to a function with the indicated NAME.
6858
6859 FIXME:Can't we find a neater way to do this mapping? */
6860
6861 tree
6862 in_charge_arg_for_name (tree name)
6863 {
6864 if (name == base_ctor_identifier
6865 || name == base_dtor_identifier)
6866 return integer_zero_node;
6867 else if (name == complete_ctor_identifier)
6868 return integer_one_node;
6869 else if (name == complete_dtor_identifier)
6870 return integer_two_node;
6871 else if (name == deleting_dtor_identifier)
6872 return integer_three_node;
6873
6874 /* This function should only be called with one of the names listed
6875 above. */
6876 gcc_unreachable ();
6877 return NULL_TREE;
6878 }
6879
6880 /* Build a call to a constructor, destructor, or an assignment
6881 operator for INSTANCE, an expression with class type. NAME
6882 indicates the special member function to call; *ARGS are the
6883 arguments. ARGS may be NULL. This may change ARGS. BINFO
6884 indicates the base of INSTANCE that is to be passed as the `this'
6885 parameter to the member function called.
6886
6887 FLAGS are the LOOKUP_* flags to use when processing the call.
6888
6889 If NAME indicates a complete object constructor, INSTANCE may be
6890 NULL_TREE. In this case, the caller will call build_cplus_new to
6891 store the newly constructed object into a VAR_DECL. */
6892
6893 tree
6894 build_special_member_call (tree instance, tree name, VEC(tree,gc) **args,
6895 tree binfo, int flags, tsubst_flags_t complain)
6896 {
6897 tree fns;
6898 /* The type of the subobject to be constructed or destroyed. */
6899 tree class_type;
6900 VEC(tree,gc) *allocated = NULL;
6901 tree ret;
6902
6903 gcc_assert (name == complete_ctor_identifier
6904 || name == base_ctor_identifier
6905 || name == complete_dtor_identifier
6906 || name == base_dtor_identifier
6907 || name == deleting_dtor_identifier
6908 || name == ansi_assopname (NOP_EXPR));
6909 if (TYPE_P (binfo))
6910 {
6911 /* Resolve the name. */
6912 if (!complete_type_or_maybe_complain (binfo, NULL_TREE, complain))
6913 return error_mark_node;
6914
6915 binfo = TYPE_BINFO (binfo);
6916 }
6917
6918 gcc_assert (binfo != NULL_TREE);
6919
6920 class_type = BINFO_TYPE (binfo);
6921
6922 /* Handle the special case where INSTANCE is NULL_TREE. */
6923 if (name == complete_ctor_identifier && !instance)
6924 {
6925 instance = build_int_cst (build_pointer_type (class_type), 0);
6926 instance = build1 (INDIRECT_REF, class_type, instance);
6927 }
6928 else
6929 {
6930 if (name == complete_dtor_identifier
6931 || name == base_dtor_identifier
6932 || name == deleting_dtor_identifier)
6933 gcc_assert (args == NULL || VEC_empty (tree, *args));
6934
6935 /* Convert to the base class, if necessary. */
6936 if (!same_type_ignoring_top_level_qualifiers_p
6937 (TREE_TYPE (instance), BINFO_TYPE (binfo)))
6938 {
6939 if (name != ansi_assopname (NOP_EXPR))
6940 /* For constructors and destructors, either the base is
6941 non-virtual, or it is virtual but we are doing the
6942 conversion from a constructor or destructor for the
6943 complete object. In either case, we can convert
6944 statically. */
6945 instance = convert_to_base_statically (instance, binfo);
6946 else
6947 /* However, for assignment operators, we must convert
6948 dynamically if the base is virtual. */
6949 instance = build_base_path (PLUS_EXPR, instance,
6950 binfo, /*nonnull=*/1, complain);
6951 }
6952 }
6953
6954 gcc_assert (instance != NULL_TREE);
6955
6956 fns = lookup_fnfields (binfo, name, 1);
6957
6958 /* When making a call to a constructor or destructor for a subobject
6959 that uses virtual base classes, pass down a pointer to a VTT for
6960 the subobject. */
6961 if ((name == base_ctor_identifier
6962 || name == base_dtor_identifier)
6963 && CLASSTYPE_VBASECLASSES (class_type))
6964 {
6965 tree vtt;
6966 tree sub_vtt;
6967
6968 /* If the current function is a complete object constructor
6969 or destructor, then we fetch the VTT directly.
6970 Otherwise, we look it up using the VTT we were given. */
6971 vtt = DECL_CHAIN (CLASSTYPE_VTABLES (current_class_type));
6972 vtt = decay_conversion (vtt);
6973 vtt = build3 (COND_EXPR, TREE_TYPE (vtt),
6974 build2 (EQ_EXPR, boolean_type_node,
6975 current_in_charge_parm, integer_zero_node),
6976 current_vtt_parm,
6977 vtt);
6978 gcc_assert (BINFO_SUBVTT_INDEX (binfo));
6979 sub_vtt = fold_build_pointer_plus (vtt, BINFO_SUBVTT_INDEX (binfo));
6980
6981 if (args == NULL)
6982 {
6983 allocated = make_tree_vector ();
6984 args = &allocated;
6985 }
6986
6987 VEC_safe_insert (tree, gc, *args, 0, sub_vtt);
6988 }
6989
6990 ret = build_new_method_call (instance, fns, args,
6991 TYPE_BINFO (BINFO_TYPE (binfo)),
6992 flags, /*fn=*/NULL,
6993 complain);
6994
6995 if (allocated != NULL)
6996 release_tree_vector (allocated);
6997
6998 return ret;
6999 }
7000
7001 /* Return the NAME, as a C string. The NAME indicates a function that
7002 is a member of TYPE. *FREE_P is set to true if the caller must
7003 free the memory returned.
7004
7005 Rather than go through all of this, we should simply set the names
7006 of constructors and destructors appropriately, and dispense with
7007 ctor_identifier, dtor_identifier, etc. */
7008
7009 static char *
7010 name_as_c_string (tree name, tree type, bool *free_p)
7011 {
7012 char *pretty_name;
7013
7014 /* Assume that we will not allocate memory. */
7015 *free_p = false;
7016 /* Constructors and destructors are special. */
7017 if (IDENTIFIER_CTOR_OR_DTOR_P (name))
7018 {
7019 pretty_name
7020 = CONST_CAST (char *, identifier_to_locale (IDENTIFIER_POINTER (constructor_name (type))));
7021 /* For a destructor, add the '~'. */
7022 if (name == complete_dtor_identifier
7023 || name == base_dtor_identifier
7024 || name == deleting_dtor_identifier)
7025 {
7026 pretty_name = concat ("~", pretty_name, NULL);
7027 /* Remember that we need to free the memory allocated. */
7028 *free_p = true;
7029 }
7030 }
7031 else if (IDENTIFIER_TYPENAME_P (name))
7032 {
7033 pretty_name = concat ("operator ",
7034 type_as_string_translate (TREE_TYPE (name),
7035 TFF_PLAIN_IDENTIFIER),
7036 NULL);
7037 /* Remember that we need to free the memory allocated. */
7038 *free_p = true;
7039 }
7040 else
7041 pretty_name = CONST_CAST (char *, identifier_to_locale (IDENTIFIER_POINTER (name)));
7042
7043 return pretty_name;
7044 }
7045
7046 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
7047 be set, upon return, to the function called. ARGS may be NULL.
7048 This may change ARGS. */
7049
7050 static tree
7051 build_new_method_call_1 (tree instance, tree fns, VEC(tree,gc) **args,
7052 tree conversion_path, int flags,
7053 tree *fn_p, tsubst_flags_t complain)
7054 {
7055 struct z_candidate *candidates = 0, *cand;
7056 tree explicit_targs = NULL_TREE;
7057 tree basetype = NULL_TREE;
7058 tree access_binfo;
7059 tree optype;
7060 tree first_mem_arg = NULL_TREE;
7061 tree instance_ptr;
7062 tree name;
7063 bool skip_first_for_error;
7064 VEC(tree,gc) *user_args;
7065 tree call;
7066 tree fn;
7067 int template_only = 0;
7068 bool any_viable_p;
7069 tree orig_instance;
7070 tree orig_fns;
7071 VEC(tree,gc) *orig_args = NULL;
7072 void *p;
7073
7074 gcc_assert (instance != NULL_TREE);
7075
7076 /* We don't know what function we're going to call, yet. */
7077 if (fn_p)
7078 *fn_p = NULL_TREE;
7079
7080 if (error_operand_p (instance)
7081 || !fns || error_operand_p (fns))
7082 return error_mark_node;
7083
7084 if (!BASELINK_P (fns))
7085 {
7086 if (complain & tf_error)
7087 error ("call to non-function %qD", fns);
7088 return error_mark_node;
7089 }
7090
7091 orig_instance = instance;
7092 orig_fns = fns;
7093
7094 /* Dismantle the baselink to collect all the information we need. */
7095 if (!conversion_path)
7096 conversion_path = BASELINK_BINFO (fns);
7097 access_binfo = BASELINK_ACCESS_BINFO (fns);
7098 optype = BASELINK_OPTYPE (fns);
7099 fns = BASELINK_FUNCTIONS (fns);
7100 if (TREE_CODE (fns) == TEMPLATE_ID_EXPR)
7101 {
7102 explicit_targs = TREE_OPERAND (fns, 1);
7103 fns = TREE_OPERAND (fns, 0);
7104 template_only = 1;
7105 }
7106 gcc_assert (TREE_CODE (fns) == FUNCTION_DECL
7107 || TREE_CODE (fns) == TEMPLATE_DECL
7108 || TREE_CODE (fns) == OVERLOAD);
7109 fn = get_first_fn (fns);
7110 name = DECL_NAME (fn);
7111
7112 basetype = TYPE_MAIN_VARIANT (TREE_TYPE (instance));
7113 gcc_assert (CLASS_TYPE_P (basetype));
7114
7115 if (processing_template_decl)
7116 {
7117 orig_args = args == NULL ? NULL : make_tree_vector_copy (*args);
7118 instance = build_non_dependent_expr (instance);
7119 if (args != NULL)
7120 make_args_non_dependent (*args);
7121 }
7122
7123 user_args = args == NULL ? NULL : *args;
7124 /* Under DR 147 A::A() is an invalid constructor call,
7125 not a functional cast. */
7126 if (DECL_MAYBE_IN_CHARGE_CONSTRUCTOR_P (fn))
7127 {
7128 if (! (complain & tf_error))
7129 return error_mark_node;
7130
7131 permerror (input_location,
7132 "cannot call constructor %<%T::%D%> directly",
7133 basetype, name);
7134 permerror (input_location, " for a function-style cast, remove the "
7135 "redundant %<::%D%>", name);
7136 call = build_functional_cast (basetype, build_tree_list_vec (user_args),
7137 complain);
7138 return call;
7139 }
7140
7141 /* Figure out whether to skip the first argument for the error
7142 message we will display to users if an error occurs. We don't
7143 want to display any compiler-generated arguments. The "this"
7144 pointer hasn't been added yet. However, we must remove the VTT
7145 pointer if this is a call to a base-class constructor or
7146 destructor. */
7147 skip_first_for_error = false;
7148 if (IDENTIFIER_CTOR_OR_DTOR_P (name))
7149 {
7150 /* Callers should explicitly indicate whether they want to construct
7151 the complete object or just the part without virtual bases. */
7152 gcc_assert (name != ctor_identifier);
7153 /* Similarly for destructors. */
7154 gcc_assert (name != dtor_identifier);
7155 /* Remove the VTT pointer, if present. */
7156 if ((name == base_ctor_identifier || name == base_dtor_identifier)
7157 && CLASSTYPE_VBASECLASSES (basetype))
7158 skip_first_for_error = true;
7159 }
7160
7161 /* Process the argument list. */
7162 if (args != NULL && *args != NULL)
7163 {
7164 *args = resolve_args (*args, complain);
7165 if (*args == NULL)
7166 return error_mark_node;
7167 }
7168
7169 instance_ptr = build_this (instance);
7170
7171 /* It's OK to call destructors and constructors on cv-qualified objects.
7172 Therefore, convert the INSTANCE_PTR to the unqualified type, if
7173 necessary. */
7174 if (DECL_DESTRUCTOR_P (fn)
7175 || DECL_CONSTRUCTOR_P (fn))
7176 {
7177 tree type = build_pointer_type (basetype);
7178 if (!same_type_p (type, TREE_TYPE (instance_ptr)))
7179 instance_ptr = build_nop (type, instance_ptr);
7180 }
7181 if (DECL_DESTRUCTOR_P (fn))
7182 name = complete_dtor_identifier;
7183
7184 first_mem_arg = instance_ptr;
7185
7186 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7187 p = conversion_obstack_alloc (0);
7188
7189 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
7190 initializer, not T({ }). */
7191 if (DECL_CONSTRUCTOR_P (fn) && args != NULL && !VEC_empty (tree, *args)
7192 && BRACE_ENCLOSED_INITIALIZER_P (VEC_index (tree, *args, 0))
7193 && CONSTRUCTOR_IS_DIRECT_INIT (VEC_index (tree, *args, 0)))
7194 {
7195 tree init_list = VEC_index (tree, *args, 0);
7196
7197 gcc_assert (VEC_length (tree, *args) == 1
7198 && !(flags & LOOKUP_ONLYCONVERTING));
7199
7200 /* If the initializer list has no elements and T is a class type with
7201 a default constructor, the object is value-initialized. Handle
7202 this here so we don't need to handle it wherever we use
7203 build_special_member_call. */
7204 if (CONSTRUCTOR_NELTS (init_list) == 0
7205 && TYPE_HAS_DEFAULT_CONSTRUCTOR (basetype)
7206 && !processing_template_decl)
7207 {
7208 tree ob, init = build_value_init (basetype, complain);
7209 if (integer_zerop (instance_ptr))
7210 return get_target_expr_sfinae (init, complain);
7211 ob = build_fold_indirect_ref (instance_ptr);
7212 init = build2 (INIT_EXPR, TREE_TYPE (ob), ob, init);
7213 TREE_SIDE_EFFECTS (init) = true;
7214 return init;
7215 }
7216
7217 add_list_candidates (fns, first_mem_arg, init_list,
7218 basetype, explicit_targs, template_only,
7219 conversion_path, access_binfo, flags, &candidates);
7220 }
7221 else
7222 {
7223 add_candidates (fns, first_mem_arg, user_args, optype,
7224 explicit_targs, template_only, conversion_path,
7225 access_binfo, flags, &candidates);
7226 }
7227 any_viable_p = false;
7228 candidates = splice_viable (candidates, pedantic, &any_viable_p);
7229
7230 if (!any_viable_p)
7231 {
7232 if (complain & tf_error)
7233 {
7234 if (!COMPLETE_OR_OPEN_TYPE_P (basetype))
7235 cxx_incomplete_type_error (instance_ptr, basetype);
7236 else if (optype)
7237 error ("no matching function for call to %<%T::operator %T(%A)%#V%>",
7238 basetype, optype, build_tree_list_vec (user_args),
7239 TREE_TYPE (TREE_TYPE (instance_ptr)));
7240 else
7241 {
7242 char *pretty_name;
7243 bool free_p;
7244 tree arglist;
7245
7246 pretty_name = name_as_c_string (name, basetype, &free_p);
7247 arglist = build_tree_list_vec (user_args);
7248 if (skip_first_for_error)
7249 arglist = TREE_CHAIN (arglist);
7250 error ("no matching function for call to %<%T::%s(%A)%#V%>",
7251 basetype, pretty_name, arglist,
7252 TREE_TYPE (TREE_TYPE (instance_ptr)));
7253 if (free_p)
7254 free (pretty_name);
7255 }
7256 print_z_candidates (location_of (name), candidates);
7257 }
7258 call = error_mark_node;
7259 }
7260 else
7261 {
7262 cand = tourney (candidates);
7263 if (cand == 0)
7264 {
7265 char *pretty_name;
7266 bool free_p;
7267 tree arglist;
7268
7269 if (complain & tf_error)
7270 {
7271 pretty_name = name_as_c_string (name, basetype, &free_p);
7272 arglist = build_tree_list_vec (user_args);
7273 if (skip_first_for_error)
7274 arglist = TREE_CHAIN (arglist);
7275 error ("call of overloaded %<%s(%A)%> is ambiguous", pretty_name,
7276 arglist);
7277 print_z_candidates (location_of (name), candidates);
7278 if (free_p)
7279 free (pretty_name);
7280 }
7281 call = error_mark_node;
7282 }
7283 else
7284 {
7285 fn = cand->fn;
7286
7287 if (!(flags & LOOKUP_NONVIRTUAL)
7288 && DECL_PURE_VIRTUAL_P (fn)
7289 && instance == current_class_ref
7290 && (DECL_CONSTRUCTOR_P (current_function_decl)
7291 || DECL_DESTRUCTOR_P (current_function_decl))
7292 && (complain & tf_warning))
7293 /* This is not an error, it is runtime undefined
7294 behavior. */
7295 warning (0, (DECL_CONSTRUCTOR_P (current_function_decl) ?
7296 "pure virtual %q#D called from constructor"
7297 : "pure virtual %q#D called from destructor"),
7298 fn);
7299
7300 if (TREE_CODE (TREE_TYPE (fn)) == METHOD_TYPE
7301 && is_dummy_object (instance_ptr))
7302 {
7303 if (complain & tf_error)
7304 error ("cannot call member function %qD without object",
7305 fn);
7306 call = error_mark_node;
7307 }
7308 else
7309 {
7310 /* Optimize away vtable lookup if we know that this function
7311 can't be overridden. */
7312 if (DECL_VINDEX (fn) && ! (flags & LOOKUP_NONVIRTUAL)
7313 && (resolves_to_fixed_type_p (instance, 0)
7314 || DECL_FINAL_P (fn) || CLASSTYPE_FINAL (basetype)))
7315 flags |= LOOKUP_NONVIRTUAL;
7316 if (explicit_targs)
7317 flags |= LOOKUP_EXPLICIT_TMPL_ARGS;
7318 /* Now we know what function is being called. */
7319 if (fn_p)
7320 *fn_p = fn;
7321 /* Build the actual CALL_EXPR. */
7322 call = build_over_call (cand, flags, complain);
7323 /* In an expression of the form `a->f()' where `f' turns
7324 out to be a static member function, `a' is
7325 none-the-less evaluated. */
7326 if (TREE_CODE (TREE_TYPE (fn)) != METHOD_TYPE
7327 && !is_dummy_object (instance_ptr)
7328 && TREE_SIDE_EFFECTS (instance_ptr))
7329 call = build2 (COMPOUND_EXPR, TREE_TYPE (call),
7330 instance_ptr, call);
7331 else if (call != error_mark_node
7332 && DECL_DESTRUCTOR_P (cand->fn)
7333 && !VOID_TYPE_P (TREE_TYPE (call)))
7334 /* An explicit call of the form "x->~X()" has type
7335 "void". However, on platforms where destructors
7336 return "this" (i.e., those where
7337 targetm.cxx.cdtor_returns_this is true), such calls
7338 will appear to have a return value of pointer type
7339 to the low-level call machinery. We do not want to
7340 change the low-level machinery, since we want to be
7341 able to optimize "delete f()" on such platforms as
7342 "operator delete(~X(f()))" (rather than generating
7343 "t = f(), ~X(t), operator delete (t)"). */
7344 call = build_nop (void_type_node, call);
7345 }
7346 }
7347 }
7348
7349 if (processing_template_decl && call != error_mark_node)
7350 {
7351 bool cast_to_void = false;
7352
7353 if (TREE_CODE (call) == COMPOUND_EXPR)
7354 call = TREE_OPERAND (call, 1);
7355 else if (TREE_CODE (call) == NOP_EXPR)
7356 {
7357 cast_to_void = true;
7358 call = TREE_OPERAND (call, 0);
7359 }
7360 if (TREE_CODE (call) == INDIRECT_REF)
7361 call = TREE_OPERAND (call, 0);
7362 call = (build_min_non_dep_call_vec
7363 (call,
7364 build_min (COMPONENT_REF, TREE_TYPE (CALL_EXPR_FN (call)),
7365 orig_instance, orig_fns, NULL_TREE),
7366 orig_args));
7367 call = convert_from_reference (call);
7368 if (cast_to_void)
7369 call = build_nop (void_type_node, call);
7370 }
7371
7372 /* Free all the conversions we allocated. */
7373 obstack_free (&conversion_obstack, p);
7374
7375 if (orig_args != NULL)
7376 release_tree_vector (orig_args);
7377
7378 return call;
7379 }
7380
7381 /* Wrapper for above. */
7382
7383 tree
7384 build_new_method_call (tree instance, tree fns, VEC(tree,gc) **args,
7385 tree conversion_path, int flags,
7386 tree *fn_p, tsubst_flags_t complain)
7387 {
7388 tree ret;
7389 bool subtime = timevar_cond_start (TV_OVERLOAD);
7390 ret = build_new_method_call_1 (instance, fns, args, conversion_path, flags,
7391 fn_p, complain);
7392 timevar_cond_stop (TV_OVERLOAD, subtime);
7393 return ret;
7394 }
7395
7396 /* Returns true iff standard conversion sequence ICS1 is a proper
7397 subsequence of ICS2. */
7398
7399 static bool
7400 is_subseq (conversion *ics1, conversion *ics2)
7401 {
7402 /* We can assume that a conversion of the same code
7403 between the same types indicates a subsequence since we only get
7404 here if the types we are converting from are the same. */
7405
7406 while (ics1->kind == ck_rvalue
7407 || ics1->kind == ck_lvalue)
7408 ics1 = ics1->u.next;
7409
7410 while (1)
7411 {
7412 while (ics2->kind == ck_rvalue
7413 || ics2->kind == ck_lvalue)
7414 ics2 = ics2->u.next;
7415
7416 if (ics2->kind == ck_user
7417 || ics2->kind == ck_ambig
7418 || ics2->kind == ck_aggr
7419 || ics2->kind == ck_list
7420 || ics2->kind == ck_identity)
7421 /* At this point, ICS1 cannot be a proper subsequence of
7422 ICS2. We can get a USER_CONV when we are comparing the
7423 second standard conversion sequence of two user conversion
7424 sequences. */
7425 return false;
7426
7427 ics2 = ics2->u.next;
7428
7429 if (ics2->kind == ics1->kind
7430 && same_type_p (ics2->type, ics1->type)
7431 && same_type_p (ics2->u.next->type,
7432 ics1->u.next->type))
7433 return true;
7434 }
7435 }
7436
7437 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
7438 be any _TYPE nodes. */
7439
7440 bool
7441 is_properly_derived_from (tree derived, tree base)
7442 {
7443 if (!CLASS_TYPE_P (derived) || !CLASS_TYPE_P (base))
7444 return false;
7445
7446 /* We only allow proper derivation here. The DERIVED_FROM_P macro
7447 considers every class derived from itself. */
7448 return (!same_type_ignoring_top_level_qualifiers_p (derived, base)
7449 && DERIVED_FROM_P (base, derived));
7450 }
7451
7452 /* We build the ICS for an implicit object parameter as a pointer
7453 conversion sequence. However, such a sequence should be compared
7454 as if it were a reference conversion sequence. If ICS is the
7455 implicit conversion sequence for an implicit object parameter,
7456 modify it accordingly. */
7457
7458 static void
7459 maybe_handle_implicit_object (conversion **ics)
7460 {
7461 if ((*ics)->this_p)
7462 {
7463 /* [over.match.funcs]
7464
7465 For non-static member functions, the type of the
7466 implicit object parameter is "reference to cv X"
7467 where X is the class of which the function is a
7468 member and cv is the cv-qualification on the member
7469 function declaration. */
7470 conversion *t = *ics;
7471 tree reference_type;
7472
7473 /* The `this' parameter is a pointer to a class type. Make the
7474 implicit conversion talk about a reference to that same class
7475 type. */
7476 reference_type = TREE_TYPE (t->type);
7477 reference_type = build_reference_type (reference_type);
7478
7479 if (t->kind == ck_qual)
7480 t = t->u.next;
7481 if (t->kind == ck_ptr)
7482 t = t->u.next;
7483 t = build_identity_conv (TREE_TYPE (t->type), NULL_TREE);
7484 t = direct_reference_binding (reference_type, t);
7485 t->this_p = 1;
7486 t->rvaluedness_matches_p = 0;
7487 *ics = t;
7488 }
7489 }
7490
7491 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
7492 and return the initial reference binding conversion. Otherwise,
7493 leave *ICS unchanged and return NULL. */
7494
7495 static conversion *
7496 maybe_handle_ref_bind (conversion **ics)
7497 {
7498 if ((*ics)->kind == ck_ref_bind)
7499 {
7500 conversion *old_ics = *ics;
7501 *ics = old_ics->u.next;
7502 (*ics)->user_conv_p = old_ics->user_conv_p;
7503 return old_ics;
7504 }
7505
7506 return NULL;
7507 }
7508
7509 /* Compare two implicit conversion sequences according to the rules set out in
7510 [over.ics.rank]. Return values:
7511
7512 1: ics1 is better than ics2
7513 -1: ics2 is better than ics1
7514 0: ics1 and ics2 are indistinguishable */
7515
7516 static int
7517 compare_ics (conversion *ics1, conversion *ics2)
7518 {
7519 tree from_type1;
7520 tree from_type2;
7521 tree to_type1;
7522 tree to_type2;
7523 tree deref_from_type1 = NULL_TREE;
7524 tree deref_from_type2 = NULL_TREE;
7525 tree deref_to_type1 = NULL_TREE;
7526 tree deref_to_type2 = NULL_TREE;
7527 conversion_rank rank1, rank2;
7528
7529 /* REF_BINDING is nonzero if the result of the conversion sequence
7530 is a reference type. In that case REF_CONV is the reference
7531 binding conversion. */
7532 conversion *ref_conv1;
7533 conversion *ref_conv2;
7534
7535 /* Handle implicit object parameters. */
7536 maybe_handle_implicit_object (&ics1);
7537 maybe_handle_implicit_object (&ics2);
7538
7539 /* Handle reference parameters. */
7540 ref_conv1 = maybe_handle_ref_bind (&ics1);
7541 ref_conv2 = maybe_handle_ref_bind (&ics2);
7542
7543 /* List-initialization sequence L1 is a better conversion sequence than
7544 list-initialization sequence L2 if L1 converts to
7545 std::initializer_list<X> for some X and L2 does not. */
7546 if (ics1->kind == ck_list && ics2->kind != ck_list)
7547 return 1;
7548 if (ics2->kind == ck_list && ics1->kind != ck_list)
7549 return -1;
7550
7551 /* [over.ics.rank]
7552
7553 When comparing the basic forms of implicit conversion sequences (as
7554 defined in _over.best.ics_)
7555
7556 --a standard conversion sequence (_over.ics.scs_) is a better
7557 conversion sequence than a user-defined conversion sequence
7558 or an ellipsis conversion sequence, and
7559
7560 --a user-defined conversion sequence (_over.ics.user_) is a
7561 better conversion sequence than an ellipsis conversion sequence
7562 (_over.ics.ellipsis_). */
7563 rank1 = CONVERSION_RANK (ics1);
7564 rank2 = CONVERSION_RANK (ics2);
7565
7566 if (rank1 > rank2)
7567 return -1;
7568 else if (rank1 < rank2)
7569 return 1;
7570
7571 if (rank1 == cr_bad)
7572 {
7573 /* Both ICS are bad. We try to make a decision based on what would
7574 have happened if they'd been good. This is not an extension,
7575 we'll still give an error when we build up the call; this just
7576 helps us give a more helpful error message. */
7577 rank1 = BAD_CONVERSION_RANK (ics1);
7578 rank2 = BAD_CONVERSION_RANK (ics2);
7579
7580 if (rank1 > rank2)
7581 return -1;
7582 else if (rank1 < rank2)
7583 return 1;
7584
7585 /* We couldn't make up our minds; try to figure it out below. */
7586 }
7587
7588 if (ics1->ellipsis_p)
7589 /* Both conversions are ellipsis conversions. */
7590 return 0;
7591
7592 /* User-defined conversion sequence U1 is a better conversion sequence
7593 than another user-defined conversion sequence U2 if they contain the
7594 same user-defined conversion operator or constructor and if the sec-
7595 ond standard conversion sequence of U1 is better than the second
7596 standard conversion sequence of U2. */
7597
7598 /* Handle list-conversion with the same code even though it isn't always
7599 ranked as a user-defined conversion and it doesn't have a second
7600 standard conversion sequence; it will still have the desired effect.
7601 Specifically, we need to do the reference binding comparison at the
7602 end of this function. */
7603
7604 if (ics1->user_conv_p || ics1->kind == ck_list)
7605 {
7606 conversion *t1;
7607 conversion *t2;
7608
7609 for (t1 = ics1; t1->kind != ck_user; t1 = t1->u.next)
7610 if (t1->kind == ck_ambig || t1->kind == ck_aggr
7611 || t1->kind == ck_list)
7612 break;
7613 for (t2 = ics2; t2->kind != ck_user; t2 = t2->u.next)
7614 if (t2->kind == ck_ambig || t2->kind == ck_aggr
7615 || t2->kind == ck_list)
7616 break;
7617
7618 if (t1->kind != t2->kind)
7619 return 0;
7620 else if (t1->kind == ck_user)
7621 {
7622 if (t1->cand->fn != t2->cand->fn)
7623 return 0;
7624 }
7625 else
7626 {
7627 /* For ambiguous or aggregate conversions, use the target type as
7628 a proxy for the conversion function. */
7629 if (!same_type_ignoring_top_level_qualifiers_p (t1->type, t2->type))
7630 return 0;
7631 }
7632
7633 /* We can just fall through here, after setting up
7634 FROM_TYPE1 and FROM_TYPE2. */
7635 from_type1 = t1->type;
7636 from_type2 = t2->type;
7637 }
7638 else
7639 {
7640 conversion *t1;
7641 conversion *t2;
7642
7643 /* We're dealing with two standard conversion sequences.
7644
7645 [over.ics.rank]
7646
7647 Standard conversion sequence S1 is a better conversion
7648 sequence than standard conversion sequence S2 if
7649
7650 --S1 is a proper subsequence of S2 (comparing the conversion
7651 sequences in the canonical form defined by _over.ics.scs_,
7652 excluding any Lvalue Transformation; the identity
7653 conversion sequence is considered to be a subsequence of
7654 any non-identity conversion sequence */
7655
7656 t1 = ics1;
7657 while (t1->kind != ck_identity)
7658 t1 = t1->u.next;
7659 from_type1 = t1->type;
7660
7661 t2 = ics2;
7662 while (t2->kind != ck_identity)
7663 t2 = t2->u.next;
7664 from_type2 = t2->type;
7665 }
7666
7667 /* One sequence can only be a subsequence of the other if they start with
7668 the same type. They can start with different types when comparing the
7669 second standard conversion sequence in two user-defined conversion
7670 sequences. */
7671 if (same_type_p (from_type1, from_type2))
7672 {
7673 if (is_subseq (ics1, ics2))
7674 return 1;
7675 if (is_subseq (ics2, ics1))
7676 return -1;
7677 }
7678
7679 /* [over.ics.rank]
7680
7681 Or, if not that,
7682
7683 --the rank of S1 is better than the rank of S2 (by the rules
7684 defined below):
7685
7686 Standard conversion sequences are ordered by their ranks: an Exact
7687 Match is a better conversion than a Promotion, which is a better
7688 conversion than a Conversion.
7689
7690 Two conversion sequences with the same rank are indistinguishable
7691 unless one of the following rules applies:
7692
7693 --A conversion that does not a convert a pointer, pointer to member,
7694 or std::nullptr_t to bool is better than one that does.
7695
7696 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
7697 so that we do not have to check it explicitly. */
7698 if (ics1->rank < ics2->rank)
7699 return 1;
7700 else if (ics2->rank < ics1->rank)
7701 return -1;
7702
7703 to_type1 = ics1->type;
7704 to_type2 = ics2->type;
7705
7706 /* A conversion from scalar arithmetic type to complex is worse than a
7707 conversion between scalar arithmetic types. */
7708 if (same_type_p (from_type1, from_type2)
7709 && ARITHMETIC_TYPE_P (from_type1)
7710 && ARITHMETIC_TYPE_P (to_type1)
7711 && ARITHMETIC_TYPE_P (to_type2)
7712 && ((TREE_CODE (to_type1) == COMPLEX_TYPE)
7713 != (TREE_CODE (to_type2) == COMPLEX_TYPE)))
7714 {
7715 if (TREE_CODE (to_type1) == COMPLEX_TYPE)
7716 return -1;
7717 else
7718 return 1;
7719 }
7720
7721 if (TYPE_PTR_P (from_type1)
7722 && TYPE_PTR_P (from_type2)
7723 && TYPE_PTR_P (to_type1)
7724 && TYPE_PTR_P (to_type2))
7725 {
7726 deref_from_type1 = TREE_TYPE (from_type1);
7727 deref_from_type2 = TREE_TYPE (from_type2);
7728 deref_to_type1 = TREE_TYPE (to_type1);
7729 deref_to_type2 = TREE_TYPE (to_type2);
7730 }
7731 /* The rules for pointers to members A::* are just like the rules
7732 for pointers A*, except opposite: if B is derived from A then
7733 A::* converts to B::*, not vice versa. For that reason, we
7734 switch the from_ and to_ variables here. */
7735 else if ((TYPE_PTRMEM_P (from_type1) && TYPE_PTRMEM_P (from_type2)
7736 && TYPE_PTRMEM_P (to_type1) && TYPE_PTRMEM_P (to_type2))
7737 || (TYPE_PTRMEMFUNC_P (from_type1)
7738 && TYPE_PTRMEMFUNC_P (from_type2)
7739 && TYPE_PTRMEMFUNC_P (to_type1)
7740 && TYPE_PTRMEMFUNC_P (to_type2)))
7741 {
7742 deref_to_type1 = TYPE_PTRMEM_CLASS_TYPE (from_type1);
7743 deref_to_type2 = TYPE_PTRMEM_CLASS_TYPE (from_type2);
7744 deref_from_type1 = TYPE_PTRMEM_CLASS_TYPE (to_type1);
7745 deref_from_type2 = TYPE_PTRMEM_CLASS_TYPE (to_type2);
7746 }
7747
7748 if (deref_from_type1 != NULL_TREE
7749 && RECORD_OR_UNION_CODE_P (TREE_CODE (deref_from_type1))
7750 && RECORD_OR_UNION_CODE_P (TREE_CODE (deref_from_type2)))
7751 {
7752 /* This was one of the pointer or pointer-like conversions.
7753
7754 [over.ics.rank]
7755
7756 --If class B is derived directly or indirectly from class A,
7757 conversion of B* to A* is better than conversion of B* to
7758 void*, and conversion of A* to void* is better than
7759 conversion of B* to void*. */
7760 if (TREE_CODE (deref_to_type1) == VOID_TYPE
7761 && TREE_CODE (deref_to_type2) == VOID_TYPE)
7762 {
7763 if (is_properly_derived_from (deref_from_type1,
7764 deref_from_type2))
7765 return -1;
7766 else if (is_properly_derived_from (deref_from_type2,
7767 deref_from_type1))
7768 return 1;
7769 }
7770 else if (TREE_CODE (deref_to_type1) == VOID_TYPE
7771 || TREE_CODE (deref_to_type2) == VOID_TYPE)
7772 {
7773 if (same_type_p (deref_from_type1, deref_from_type2))
7774 {
7775 if (TREE_CODE (deref_to_type2) == VOID_TYPE)
7776 {
7777 if (is_properly_derived_from (deref_from_type1,
7778 deref_to_type1))
7779 return 1;
7780 }
7781 /* We know that DEREF_TO_TYPE1 is `void' here. */
7782 else if (is_properly_derived_from (deref_from_type1,
7783 deref_to_type2))
7784 return -1;
7785 }
7786 }
7787 else if (RECORD_OR_UNION_CODE_P (TREE_CODE (deref_to_type1))
7788 && RECORD_OR_UNION_CODE_P (TREE_CODE (deref_to_type2)))
7789 {
7790 /* [over.ics.rank]
7791
7792 --If class B is derived directly or indirectly from class A
7793 and class C is derived directly or indirectly from B,
7794
7795 --conversion of C* to B* is better than conversion of C* to
7796 A*,
7797
7798 --conversion of B* to A* is better than conversion of C* to
7799 A* */
7800 if (same_type_p (deref_from_type1, deref_from_type2))
7801 {
7802 if (is_properly_derived_from (deref_to_type1,
7803 deref_to_type2))
7804 return 1;
7805 else if (is_properly_derived_from (deref_to_type2,
7806 deref_to_type1))
7807 return -1;
7808 }
7809 else if (same_type_p (deref_to_type1, deref_to_type2))
7810 {
7811 if (is_properly_derived_from (deref_from_type2,
7812 deref_from_type1))
7813 return 1;
7814 else if (is_properly_derived_from (deref_from_type1,
7815 deref_from_type2))
7816 return -1;
7817 }
7818 }
7819 }
7820 else if (CLASS_TYPE_P (non_reference (from_type1))
7821 && same_type_p (from_type1, from_type2))
7822 {
7823 tree from = non_reference (from_type1);
7824
7825 /* [over.ics.rank]
7826
7827 --binding of an expression of type C to a reference of type
7828 B& is better than binding an expression of type C to a
7829 reference of type A&
7830
7831 --conversion of C to B is better than conversion of C to A, */
7832 if (is_properly_derived_from (from, to_type1)
7833 && is_properly_derived_from (from, to_type2))
7834 {
7835 if (is_properly_derived_from (to_type1, to_type2))
7836 return 1;
7837 else if (is_properly_derived_from (to_type2, to_type1))
7838 return -1;
7839 }
7840 }
7841 else if (CLASS_TYPE_P (non_reference (to_type1))
7842 && same_type_p (to_type1, to_type2))
7843 {
7844 tree to = non_reference (to_type1);
7845
7846 /* [over.ics.rank]
7847
7848 --binding of an expression of type B to a reference of type
7849 A& is better than binding an expression of type C to a
7850 reference of type A&,
7851
7852 --conversion of B to A is better than conversion of C to A */
7853 if (is_properly_derived_from (from_type1, to)
7854 && is_properly_derived_from (from_type2, to))
7855 {
7856 if (is_properly_derived_from (from_type2, from_type1))
7857 return 1;
7858 else if (is_properly_derived_from (from_type1, from_type2))
7859 return -1;
7860 }
7861 }
7862
7863 /* [over.ics.rank]
7864
7865 --S1 and S2 differ only in their qualification conversion and yield
7866 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
7867 qualification signature of type T1 is a proper subset of the cv-
7868 qualification signature of type T2 */
7869 if (ics1->kind == ck_qual
7870 && ics2->kind == ck_qual
7871 && same_type_p (from_type1, from_type2))
7872 {
7873 int result = comp_cv_qual_signature (to_type1, to_type2);
7874 if (result != 0)
7875 return result;
7876 }
7877
7878 /* [over.ics.rank]
7879
7880 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
7881 to an implicit object parameter, and either S1 binds an lvalue reference
7882 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
7883 reference to an rvalue and S2 binds an lvalue reference
7884 (C++0x draft standard, 13.3.3.2)
7885
7886 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
7887 types to which the references refer are the same type except for
7888 top-level cv-qualifiers, and the type to which the reference
7889 initialized by S2 refers is more cv-qualified than the type to
7890 which the reference initialized by S1 refers.
7891
7892 DR 1328 [over.match.best]: the context is an initialization by
7893 conversion function for direct reference binding (13.3.1.6) of a
7894 reference to function type, the return type of F1 is the same kind of
7895 reference (i.e. lvalue or rvalue) as the reference being initialized,
7896 and the return type of F2 is not. */
7897
7898 if (ref_conv1 && ref_conv2)
7899 {
7900 if (!ref_conv1->this_p && !ref_conv2->this_p
7901 && (ref_conv1->rvaluedness_matches_p
7902 != ref_conv2->rvaluedness_matches_p)
7903 && (same_type_p (ref_conv1->type, ref_conv2->type)
7904 || (TYPE_REF_IS_RVALUE (ref_conv1->type)
7905 != TYPE_REF_IS_RVALUE (ref_conv2->type))))
7906 {
7907 return (ref_conv1->rvaluedness_matches_p
7908 - ref_conv2->rvaluedness_matches_p);
7909 }
7910
7911 if (same_type_ignoring_top_level_qualifiers_p (to_type1, to_type2))
7912 return comp_cv_qualification (TREE_TYPE (ref_conv2->type),
7913 TREE_TYPE (ref_conv1->type));
7914 }
7915
7916 /* Neither conversion sequence is better than the other. */
7917 return 0;
7918 }
7919
7920 /* The source type for this standard conversion sequence. */
7921
7922 static tree
7923 source_type (conversion *t)
7924 {
7925 for (;; t = t->u.next)
7926 {
7927 if (t->kind == ck_user
7928 || t->kind == ck_ambig
7929 || t->kind == ck_identity)
7930 return t->type;
7931 }
7932 gcc_unreachable ();
7933 }
7934
7935 /* Note a warning about preferring WINNER to LOSER. We do this by storing
7936 a pointer to LOSER and re-running joust to produce the warning if WINNER
7937 is actually used. */
7938
7939 static void
7940 add_warning (struct z_candidate *winner, struct z_candidate *loser)
7941 {
7942 candidate_warning *cw = (candidate_warning *)
7943 conversion_obstack_alloc (sizeof (candidate_warning));
7944 cw->loser = loser;
7945 cw->next = winner->warnings;
7946 winner->warnings = cw;
7947 }
7948
7949 /* Compare two candidates for overloading as described in
7950 [over.match.best]. Return values:
7951
7952 1: cand1 is better than cand2
7953 -1: cand2 is better than cand1
7954 0: cand1 and cand2 are indistinguishable */
7955
7956 static int
7957 joust (struct z_candidate *cand1, struct z_candidate *cand2, bool warn)
7958 {
7959 int winner = 0;
7960 int off1 = 0, off2 = 0;
7961 size_t i;
7962 size_t len;
7963
7964 /* Candidates that involve bad conversions are always worse than those
7965 that don't. */
7966 if (cand1->viable > cand2->viable)
7967 return 1;
7968 if (cand1->viable < cand2->viable)
7969 return -1;
7970
7971 /* If we have two pseudo-candidates for conversions to the same type,
7972 or two candidates for the same function, arbitrarily pick one. */
7973 if (cand1->fn == cand2->fn
7974 && (IS_TYPE_OR_DECL_P (cand1->fn)))
7975 return 1;
7976
7977 /* a viable function F1
7978 is defined to be a better function than another viable function F2 if
7979 for all arguments i, ICSi(F1) is not a worse conversion sequence than
7980 ICSi(F2), and then */
7981
7982 /* for some argument j, ICSj(F1) is a better conversion sequence than
7983 ICSj(F2) */
7984
7985 /* For comparing static and non-static member functions, we ignore
7986 the implicit object parameter of the non-static function. The
7987 standard says to pretend that the static function has an object
7988 parm, but that won't work with operator overloading. */
7989 len = cand1->num_convs;
7990 if (len != cand2->num_convs)
7991 {
7992 int static_1 = DECL_STATIC_FUNCTION_P (cand1->fn);
7993 int static_2 = DECL_STATIC_FUNCTION_P (cand2->fn);
7994
7995 gcc_assert (static_1 != static_2);
7996
7997 if (static_1)
7998 off2 = 1;
7999 else
8000 {
8001 off1 = 1;
8002 --len;
8003 }
8004 }
8005
8006 for (i = 0; i < len; ++i)
8007 {
8008 conversion *t1 = cand1->convs[i + off1];
8009 conversion *t2 = cand2->convs[i + off2];
8010 int comp = compare_ics (t1, t2);
8011
8012 if (comp != 0)
8013 {
8014 if (warn_sign_promo
8015 && (CONVERSION_RANK (t1) + CONVERSION_RANK (t2)
8016 == cr_std + cr_promotion)
8017 && t1->kind == ck_std
8018 && t2->kind == ck_std
8019 && TREE_CODE (t1->type) == INTEGER_TYPE
8020 && TREE_CODE (t2->type) == INTEGER_TYPE
8021 && (TYPE_PRECISION (t1->type)
8022 == TYPE_PRECISION (t2->type))
8023 && (TYPE_UNSIGNED (t1->u.next->type)
8024 || (TREE_CODE (t1->u.next->type)
8025 == ENUMERAL_TYPE)))
8026 {
8027 tree type = t1->u.next->type;
8028 tree type1, type2;
8029 struct z_candidate *w, *l;
8030 if (comp > 0)
8031 type1 = t1->type, type2 = t2->type,
8032 w = cand1, l = cand2;
8033 else
8034 type1 = t2->type, type2 = t1->type,
8035 w = cand2, l = cand1;
8036
8037 if (warn)
8038 {
8039 warning (OPT_Wsign_promo, "passing %qT chooses %qT over %qT",
8040 type, type1, type2);
8041 warning (OPT_Wsign_promo, " in call to %qD", w->fn);
8042 }
8043 else
8044 add_warning (w, l);
8045 }
8046
8047 if (winner && comp != winner)
8048 {
8049 winner = 0;
8050 goto tweak;
8051 }
8052 winner = comp;
8053 }
8054 }
8055
8056 /* warn about confusing overload resolution for user-defined conversions,
8057 either between a constructor and a conversion op, or between two
8058 conversion ops. */
8059 if (winner && warn_conversion && cand1->second_conv
8060 && (!DECL_CONSTRUCTOR_P (cand1->fn) || !DECL_CONSTRUCTOR_P (cand2->fn))
8061 && winner != compare_ics (cand1->second_conv, cand2->second_conv))
8062 {
8063 struct z_candidate *w, *l;
8064 bool give_warning = false;
8065
8066 if (winner == 1)
8067 w = cand1, l = cand2;
8068 else
8069 w = cand2, l = cand1;
8070
8071 /* We don't want to complain about `X::operator T1 ()'
8072 beating `X::operator T2 () const', when T2 is a no less
8073 cv-qualified version of T1. */
8074 if (DECL_CONTEXT (w->fn) == DECL_CONTEXT (l->fn)
8075 && !DECL_CONSTRUCTOR_P (w->fn) && !DECL_CONSTRUCTOR_P (l->fn))
8076 {
8077 tree t = TREE_TYPE (TREE_TYPE (l->fn));
8078 tree f = TREE_TYPE (TREE_TYPE (w->fn));
8079
8080 if (TREE_CODE (t) == TREE_CODE (f) && POINTER_TYPE_P (t))
8081 {
8082 t = TREE_TYPE (t);
8083 f = TREE_TYPE (f);
8084 }
8085 if (!comp_ptr_ttypes (t, f))
8086 give_warning = true;
8087 }
8088 else
8089 give_warning = true;
8090
8091 if (!give_warning)
8092 /*NOP*/;
8093 else if (warn)
8094 {
8095 tree source = source_type (w->convs[0]);
8096 if (! DECL_CONSTRUCTOR_P (w->fn))
8097 source = TREE_TYPE (source);
8098 if (warning (OPT_Wconversion, "choosing %qD over %qD", w->fn, l->fn)
8099 && warning (OPT_Wconversion, " for conversion from %qT to %qT",
8100 source, w->second_conv->type))
8101 {
8102 inform (input_location, " because conversion sequence for the argument is better");
8103 }
8104 }
8105 else
8106 add_warning (w, l);
8107 }
8108
8109 if (winner)
8110 return winner;
8111
8112 /* DR 495 moved this tiebreaker above the template ones. */
8113 /* or, if not that,
8114 the context is an initialization by user-defined conversion (see
8115 _dcl.init_ and _over.match.user_) and the standard conversion
8116 sequence from the return type of F1 to the destination type (i.e.,
8117 the type of the entity being initialized) is a better conversion
8118 sequence than the standard conversion sequence from the return type
8119 of F2 to the destination type. */
8120
8121 if (cand1->second_conv)
8122 {
8123 winner = compare_ics (cand1->second_conv, cand2->second_conv);
8124 if (winner)
8125 return winner;
8126 }
8127
8128 /* or, if not that,
8129 F1 is a non-template function and F2 is a template function
8130 specialization. */
8131
8132 if (!cand1->template_decl && cand2->template_decl)
8133 return 1;
8134 else if (cand1->template_decl && !cand2->template_decl)
8135 return -1;
8136
8137 /* or, if not that,
8138 F1 and F2 are template functions and the function template for F1 is
8139 more specialized than the template for F2 according to the partial
8140 ordering rules. */
8141
8142 if (cand1->template_decl && cand2->template_decl)
8143 {
8144 winner = more_specialized_fn
8145 (TI_TEMPLATE (cand1->template_decl),
8146 TI_TEMPLATE (cand2->template_decl),
8147 /* [temp.func.order]: The presence of unused ellipsis and default
8148 arguments has no effect on the partial ordering of function
8149 templates. add_function_candidate() will not have
8150 counted the "this" argument for constructors. */
8151 cand1->num_convs + DECL_CONSTRUCTOR_P (cand1->fn));
8152 if (winner)
8153 return winner;
8154 }
8155
8156 /* Check whether we can discard a builtin candidate, either because we
8157 have two identical ones or matching builtin and non-builtin candidates.
8158
8159 (Pedantically in the latter case the builtin which matched the user
8160 function should not be added to the overload set, but we spot it here.
8161
8162 [over.match.oper]
8163 ... the builtin candidates include ...
8164 - do not have the same parameter type list as any non-template
8165 non-member candidate. */
8166
8167 if (TREE_CODE (cand1->fn) == IDENTIFIER_NODE
8168 || TREE_CODE (cand2->fn) == IDENTIFIER_NODE)
8169 {
8170 for (i = 0; i < len; ++i)
8171 if (!same_type_p (cand1->convs[i]->type,
8172 cand2->convs[i]->type))
8173 break;
8174 if (i == cand1->num_convs)
8175 {
8176 if (cand1->fn == cand2->fn)
8177 /* Two built-in candidates; arbitrarily pick one. */
8178 return 1;
8179 else if (TREE_CODE (cand1->fn) == IDENTIFIER_NODE)
8180 /* cand1 is built-in; prefer cand2. */
8181 return -1;
8182 else
8183 /* cand2 is built-in; prefer cand1. */
8184 return 1;
8185 }
8186 }
8187
8188 /* If the two function declarations represent the same function (this can
8189 happen with declarations in multiple scopes and arg-dependent lookup),
8190 arbitrarily choose one. But first make sure the default args we're
8191 using match. */
8192 if (DECL_P (cand1->fn) && DECL_P (cand2->fn)
8193 && equal_functions (cand1->fn, cand2->fn))
8194 {
8195 tree parms1 = TYPE_ARG_TYPES (TREE_TYPE (cand1->fn));
8196 tree parms2 = TYPE_ARG_TYPES (TREE_TYPE (cand2->fn));
8197
8198 gcc_assert (!DECL_CONSTRUCTOR_P (cand1->fn));
8199
8200 for (i = 0; i < len; ++i)
8201 {
8202 /* Don't crash if the fn is variadic. */
8203 if (!parms1)
8204 break;
8205 parms1 = TREE_CHAIN (parms1);
8206 parms2 = TREE_CHAIN (parms2);
8207 }
8208
8209 if (off1)
8210 parms1 = TREE_CHAIN (parms1);
8211 else if (off2)
8212 parms2 = TREE_CHAIN (parms2);
8213
8214 for (; parms1; ++i)
8215 {
8216 if (!cp_tree_equal (TREE_PURPOSE (parms1),
8217 TREE_PURPOSE (parms2)))
8218 {
8219 if (warn)
8220 {
8221 permerror (input_location, "default argument mismatch in "
8222 "overload resolution");
8223 inform (input_location,
8224 " candidate 1: %q+#F", cand1->fn);
8225 inform (input_location,
8226 " candidate 2: %q+#F", cand2->fn);
8227 }
8228 else
8229 add_warning (cand1, cand2);
8230 break;
8231 }
8232 parms1 = TREE_CHAIN (parms1);
8233 parms2 = TREE_CHAIN (parms2);
8234 }
8235
8236 return 1;
8237 }
8238
8239 tweak:
8240
8241 /* Extension: If the worst conversion for one candidate is worse than the
8242 worst conversion for the other, take the first. */
8243 if (!pedantic)
8244 {
8245 conversion_rank rank1 = cr_identity, rank2 = cr_identity;
8246 struct z_candidate *w = 0, *l = 0;
8247
8248 for (i = 0; i < len; ++i)
8249 {
8250 if (CONVERSION_RANK (cand1->convs[i+off1]) > rank1)
8251 rank1 = CONVERSION_RANK (cand1->convs[i+off1]);
8252 if (CONVERSION_RANK (cand2->convs[i + off2]) > rank2)
8253 rank2 = CONVERSION_RANK (cand2->convs[i + off2]);
8254 }
8255 if (rank1 < rank2)
8256 winner = 1, w = cand1, l = cand2;
8257 if (rank1 > rank2)
8258 winner = -1, w = cand2, l = cand1;
8259 if (winner)
8260 {
8261 /* Don't choose a deleted function over ambiguity. */
8262 if (DECL_P (w->fn) && DECL_DELETED_FN (w->fn))
8263 return 0;
8264 if (warn)
8265 {
8266 pedwarn (input_location, 0,
8267 "ISO C++ says that these are ambiguous, even "
8268 "though the worst conversion for the first is better than "
8269 "the worst conversion for the second:");
8270 print_z_candidate (_("candidate 1:"), w);
8271 print_z_candidate (_("candidate 2:"), l);
8272 }
8273 else
8274 add_warning (w, l);
8275 return winner;
8276 }
8277 }
8278
8279 gcc_assert (!winner);
8280 return 0;
8281 }
8282
8283 /* Given a list of candidates for overloading, find the best one, if any.
8284 This algorithm has a worst case of O(2n) (winner is last), and a best
8285 case of O(n/2) (totally ambiguous); much better than a sorting
8286 algorithm. */
8287
8288 static struct z_candidate *
8289 tourney (struct z_candidate *candidates)
8290 {
8291 struct z_candidate *champ = candidates, *challenger;
8292 int fate;
8293 int champ_compared_to_predecessor = 0;
8294
8295 /* Walk through the list once, comparing each current champ to the next
8296 candidate, knocking out a candidate or two with each comparison. */
8297
8298 for (challenger = champ->next; challenger; )
8299 {
8300 fate = joust (champ, challenger, 0);
8301 if (fate == 1)
8302 challenger = challenger->next;
8303 else
8304 {
8305 if (fate == 0)
8306 {
8307 champ = challenger->next;
8308 if (champ == 0)
8309 return NULL;
8310 champ_compared_to_predecessor = 0;
8311 }
8312 else
8313 {
8314 champ = challenger;
8315 champ_compared_to_predecessor = 1;
8316 }
8317
8318 challenger = champ->next;
8319 }
8320 }
8321
8322 /* Make sure the champ is better than all the candidates it hasn't yet
8323 been compared to. */
8324
8325 for (challenger = candidates;
8326 challenger != champ
8327 && !(champ_compared_to_predecessor && challenger->next == champ);
8328 challenger = challenger->next)
8329 {
8330 fate = joust (champ, challenger, 0);
8331 if (fate != 1)
8332 return NULL;
8333 }
8334
8335 return champ;
8336 }
8337
8338 /* Returns nonzero if things of type FROM can be converted to TO. */
8339
8340 bool
8341 can_convert (tree to, tree from)
8342 {
8343 return can_convert_arg (to, from, NULL_TREE, LOOKUP_IMPLICIT);
8344 }
8345
8346 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
8347
8348 bool
8349 can_convert_arg (tree to, tree from, tree arg, int flags)
8350 {
8351 conversion *t;
8352 void *p;
8353 bool ok_p;
8354
8355 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8356 p = conversion_obstack_alloc (0);
8357
8358 t = implicit_conversion (to, from, arg, /*c_cast_p=*/false,
8359 flags);
8360 ok_p = (t && !t->bad_p);
8361
8362 /* Free all the conversions we allocated. */
8363 obstack_free (&conversion_obstack, p);
8364
8365 return ok_p;
8366 }
8367
8368 /* Like can_convert_arg, but allows dubious conversions as well. */
8369
8370 bool
8371 can_convert_arg_bad (tree to, tree from, tree arg, int flags)
8372 {
8373 conversion *t;
8374 void *p;
8375
8376 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8377 p = conversion_obstack_alloc (0);
8378 /* Try to perform the conversion. */
8379 t = implicit_conversion (to, from, arg, /*c_cast_p=*/false,
8380 flags);
8381 /* Free all the conversions we allocated. */
8382 obstack_free (&conversion_obstack, p);
8383
8384 return t != NULL;
8385 }
8386
8387 /* Convert EXPR to TYPE. Return the converted expression.
8388
8389 Note that we allow bad conversions here because by the time we get to
8390 this point we are committed to doing the conversion. If we end up
8391 doing a bad conversion, convert_like will complain. */
8392
8393 tree
8394 perform_implicit_conversion_flags (tree type, tree expr, tsubst_flags_t complain, int flags)
8395 {
8396 conversion *conv;
8397 void *p;
8398
8399 if (error_operand_p (expr))
8400 return error_mark_node;
8401
8402 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8403 p = conversion_obstack_alloc (0);
8404
8405 conv = implicit_conversion (type, TREE_TYPE (expr), expr,
8406 /*c_cast_p=*/false,
8407 flags);
8408
8409 if (!conv)
8410 {
8411 if (complain & tf_error)
8412 {
8413 /* If expr has unknown type, then it is an overloaded function.
8414 Call instantiate_type to get good error messages. */
8415 if (TREE_TYPE (expr) == unknown_type_node)
8416 instantiate_type (type, expr, complain);
8417 else if (invalid_nonstatic_memfn_p (expr, complain))
8418 /* We gave an error. */;
8419 else
8420 error ("could not convert %qE from %qT to %qT", expr,
8421 TREE_TYPE (expr), type);
8422 }
8423 expr = error_mark_node;
8424 }
8425 else if (processing_template_decl
8426 /* As a kludge, we always perform conversions between scalar
8427 types, as IMPLICIT_CONV_EXPR confuses c_finish_omp_for. */
8428 && !(SCALAR_TYPE_P (type) && SCALAR_TYPE_P (TREE_TYPE (expr))))
8429 {
8430 /* In a template, we are only concerned about determining the
8431 type of non-dependent expressions, so we do not have to
8432 perform the actual conversion. But for initializers, we
8433 need to be able to perform it at instantiation
8434 (or fold_non_dependent_expr) time. */
8435 expr = build1 (IMPLICIT_CONV_EXPR, type, expr);
8436 if (!(flags & LOOKUP_ONLYCONVERTING))
8437 IMPLICIT_CONV_EXPR_DIRECT_INIT (expr) = true;
8438 }
8439 else
8440 expr = convert_like (conv, expr, complain);
8441
8442 /* Free all the conversions we allocated. */
8443 obstack_free (&conversion_obstack, p);
8444
8445 return expr;
8446 }
8447
8448 tree
8449 perform_implicit_conversion (tree type, tree expr, tsubst_flags_t complain)
8450 {
8451 return perform_implicit_conversion_flags (type, expr, complain, LOOKUP_IMPLICIT);
8452 }
8453
8454 /* Convert EXPR to TYPE (as a direct-initialization) if that is
8455 permitted. If the conversion is valid, the converted expression is
8456 returned. Otherwise, NULL_TREE is returned, except in the case
8457 that TYPE is a class type; in that case, an error is issued. If
8458 C_CAST_P is true, then this direct-initialization is taking
8459 place as part of a static_cast being attempted as part of a C-style
8460 cast. */
8461
8462 tree
8463 perform_direct_initialization_if_possible (tree type,
8464 tree expr,
8465 bool c_cast_p,
8466 tsubst_flags_t complain)
8467 {
8468 conversion *conv;
8469 void *p;
8470
8471 if (type == error_mark_node || error_operand_p (expr))
8472 return error_mark_node;
8473 /* [dcl.init]
8474
8475 If the destination type is a (possibly cv-qualified) class type:
8476
8477 -- If the initialization is direct-initialization ...,
8478 constructors are considered. ... If no constructor applies, or
8479 the overload resolution is ambiguous, the initialization is
8480 ill-formed. */
8481 if (CLASS_TYPE_P (type))
8482 {
8483 VEC(tree,gc) *args = make_tree_vector_single (expr);
8484 expr = build_special_member_call (NULL_TREE, complete_ctor_identifier,
8485 &args, type, LOOKUP_NORMAL, complain);
8486 release_tree_vector (args);
8487 return build_cplus_new (type, expr, complain);
8488 }
8489
8490 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8491 p = conversion_obstack_alloc (0);
8492
8493 conv = implicit_conversion (type, TREE_TYPE (expr), expr,
8494 c_cast_p,
8495 LOOKUP_NORMAL);
8496 if (!conv || conv->bad_p)
8497 expr = NULL_TREE;
8498 else
8499 expr = convert_like_real (conv, expr, NULL_TREE, 0, 0,
8500 /*issue_conversion_warnings=*/false,
8501 c_cast_p,
8502 complain);
8503
8504 /* Free all the conversions we allocated. */
8505 obstack_free (&conversion_obstack, p);
8506
8507 return expr;
8508 }
8509
8510 /* When initializing a reference that lasts longer than a full-expression,
8511 this special rule applies:
8512
8513 [class.temporary]
8514
8515 The temporary to which the reference is bound or the temporary
8516 that is the complete object to which the reference is bound
8517 persists for the lifetime of the reference.
8518
8519 The temporaries created during the evaluation of the expression
8520 initializing the reference, except the temporary to which the
8521 reference is bound, are destroyed at the end of the
8522 full-expression in which they are created.
8523
8524 In that case, we store the converted expression into a new
8525 VAR_DECL in a new scope.
8526
8527 However, we want to be careful not to create temporaries when
8528 they are not required. For example, given:
8529
8530 struct B {};
8531 struct D : public B {};
8532 D f();
8533 const B& b = f();
8534
8535 there is no need to copy the return value from "f"; we can just
8536 extend its lifetime. Similarly, given:
8537
8538 struct S {};
8539 struct T { operator S(); };
8540 T t;
8541 const S& s = t;
8542
8543 we can extend the lifetime of the return value of the conversion
8544 operator.
8545
8546 The next several functions are involved in this lifetime extension. */
8547
8548 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
8549 is being bound to a temporary. Create and return a new VAR_DECL
8550 with the indicated TYPE; this variable will store the value to
8551 which the reference is bound. */
8552
8553 tree
8554 make_temporary_var_for_ref_to_temp (tree decl, tree type)
8555 {
8556 tree var;
8557
8558 /* Create the variable. */
8559 var = create_temporary_var (type);
8560
8561 /* Register the variable. */
8562 if (TREE_STATIC (decl))
8563 {
8564 /* Namespace-scope or local static; give it a mangled name. */
8565 /* FIXME share comdat with decl? */
8566 tree name;
8567
8568 TREE_STATIC (var) = 1;
8569 name = mangle_ref_init_variable (decl);
8570 DECL_NAME (var) = name;
8571 SET_DECL_ASSEMBLER_NAME (var, name);
8572 var = pushdecl_top_level (var);
8573 }
8574 else
8575 /* Create a new cleanup level if necessary. */
8576 maybe_push_cleanup_level (type);
8577
8578 return var;
8579 }
8580
8581 /* EXPR is the initializer for a variable DECL of reference or
8582 std::initializer_list type. Create, push and return a new VAR_DECL
8583 for the initializer so that it will live as long as DECL. Any
8584 cleanup for the new variable is returned through CLEANUP, and the
8585 code to initialize the new variable is returned through INITP. */
8586
8587 static tree
8588 set_up_extended_ref_temp (tree decl, tree expr, VEC(tree,gc) **cleanups,
8589 tree *initp)
8590 {
8591 tree init;
8592 tree type;
8593 tree var;
8594
8595 /* Create the temporary variable. */
8596 type = TREE_TYPE (expr);
8597 var = make_temporary_var_for_ref_to_temp (decl, type);
8598 layout_decl (var, 0);
8599 /* If the rvalue is the result of a function call it will be
8600 a TARGET_EXPR. If it is some other construct (such as a
8601 member access expression where the underlying object is
8602 itself the result of a function call), turn it into a
8603 TARGET_EXPR here. It is important that EXPR be a
8604 TARGET_EXPR below since otherwise the INIT_EXPR will
8605 attempt to make a bitwise copy of EXPR to initialize
8606 VAR. */
8607 if (TREE_CODE (expr) != TARGET_EXPR)
8608 expr = get_target_expr (expr);
8609
8610 /* Recursively extend temps in this initializer. */
8611 TARGET_EXPR_INITIAL (expr)
8612 = extend_ref_init_temps (decl, TARGET_EXPR_INITIAL (expr), cleanups);
8613
8614 /* If the initializer is constant, put it in DECL_INITIAL so we get
8615 static initialization and use in constant expressions. */
8616 init = maybe_constant_init (expr);
8617 if (TREE_CONSTANT (init))
8618 {
8619 if (literal_type_p (type) && CP_TYPE_CONST_NON_VOLATILE_P (type))
8620 {
8621 /* 5.19 says that a constant expression can include an
8622 lvalue-rvalue conversion applied to "a glvalue of literal type
8623 that refers to a non-volatile temporary object initialized
8624 with a constant expression". Rather than try to communicate
8625 that this VAR_DECL is a temporary, just mark it constexpr.
8626
8627 Currently this is only useful for initializer_list temporaries,
8628 since reference vars can't appear in constant expressions. */
8629 DECL_DECLARED_CONSTEXPR_P (var) = true;
8630 DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (var) = true;
8631 TREE_CONSTANT (var) = true;
8632 }
8633 DECL_INITIAL (var) = init;
8634 init = NULL_TREE;
8635 }
8636 else
8637 /* Create the INIT_EXPR that will initialize the temporary
8638 variable. */
8639 init = build2 (INIT_EXPR, type, var, expr);
8640 if (at_function_scope_p ())
8641 {
8642 add_decl_expr (var);
8643
8644 if (TREE_STATIC (var))
8645 init = add_stmt_to_compound (init, register_dtor_fn (var));
8646 else
8647 {
8648 tree cleanup = cxx_maybe_build_cleanup (var, tf_warning_or_error);
8649 if (cleanup)
8650 VEC_safe_push (tree, gc, *cleanups, cleanup);
8651 }
8652
8653 /* We must be careful to destroy the temporary only
8654 after its initialization has taken place. If the
8655 initialization throws an exception, then the
8656 destructor should not be run. We cannot simply
8657 transform INIT into something like:
8658
8659 (INIT, ({ CLEANUP_STMT; }))
8660
8661 because emit_local_var always treats the
8662 initializer as a full-expression. Thus, the
8663 destructor would run too early; it would run at the
8664 end of initializing the reference variable, rather
8665 than at the end of the block enclosing the
8666 reference variable.
8667
8668 The solution is to pass back a cleanup expression
8669 which the caller is responsible for attaching to
8670 the statement tree. */
8671 }
8672 else
8673 {
8674 rest_of_decl_compilation (var, /*toplev=*/1, at_eof);
8675 if (TYPE_HAS_NONTRIVIAL_DESTRUCTOR (type))
8676 static_aggregates = tree_cons (NULL_TREE, var,
8677 static_aggregates);
8678 }
8679
8680 *initp = init;
8681 return var;
8682 }
8683
8684 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
8685 initializing a variable of that TYPE. */
8686
8687 tree
8688 initialize_reference (tree type, tree expr,
8689 int flags, tsubst_flags_t complain)
8690 {
8691 conversion *conv;
8692 void *p;
8693
8694 if (type == error_mark_node || error_operand_p (expr))
8695 return error_mark_node;
8696
8697 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8698 p = conversion_obstack_alloc (0);
8699
8700 conv = reference_binding (type, TREE_TYPE (expr), expr, /*c_cast_p=*/false,
8701 flags);
8702 if (!conv || conv->bad_p)
8703 {
8704 if (complain & tf_error)
8705 {
8706 if (conv)
8707 convert_like (conv, expr, complain);
8708 else if (!CP_TYPE_CONST_P (TREE_TYPE (type))
8709 && !TYPE_REF_IS_RVALUE (type)
8710 && !real_lvalue_p (expr))
8711 error ("invalid initialization of non-const reference of "
8712 "type %qT from an rvalue of type %qT",
8713 type, TREE_TYPE (expr));
8714 else
8715 error ("invalid initialization of reference of type "
8716 "%qT from expression of type %qT", type,
8717 TREE_TYPE (expr));
8718 }
8719 return error_mark_node;
8720 }
8721
8722 gcc_assert (conv->kind == ck_ref_bind);
8723
8724 /* Perform the conversion. */
8725 expr = convert_like (conv, expr, complain);
8726
8727 /* Free all the conversions we allocated. */
8728 obstack_free (&conversion_obstack, p);
8729
8730 return expr;
8731 }
8732
8733 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
8734 which is bound either to a reference or a std::initializer_list. */
8735
8736 static tree
8737 extend_ref_init_temps_1 (tree decl, tree init, VEC(tree,gc) **cleanups)
8738 {
8739 tree sub = init;
8740 tree *p;
8741 STRIP_NOPS (sub);
8742 if (TREE_CODE (sub) != ADDR_EXPR)
8743 return init;
8744 /* Deal with binding to a subobject. */
8745 for (p = &TREE_OPERAND (sub, 0); TREE_CODE (*p) == COMPONENT_REF; )
8746 p = &TREE_OPERAND (*p, 0);
8747 if (TREE_CODE (*p) == TARGET_EXPR)
8748 {
8749 tree subinit = NULL_TREE;
8750 *p = set_up_extended_ref_temp (decl, *p, cleanups, &subinit);
8751 if (subinit)
8752 init = build2 (COMPOUND_EXPR, TREE_TYPE (init), subinit, init);
8753 }
8754 return init;
8755 }
8756
8757 /* INIT is part of the initializer for DECL. If there are any
8758 reference or initializer lists being initialized, extend their
8759 lifetime to match that of DECL. */
8760
8761 tree
8762 extend_ref_init_temps (tree decl, tree init, VEC(tree,gc) **cleanups)
8763 {
8764 tree type = TREE_TYPE (init);
8765 if (processing_template_decl)
8766 return init;
8767 if (TREE_CODE (type) == REFERENCE_TYPE)
8768 init = extend_ref_init_temps_1 (decl, init, cleanups);
8769 else if (is_std_init_list (type))
8770 {
8771 /* The temporary array underlying a std::initializer_list
8772 is handled like a reference temporary. */
8773 tree ctor = init;
8774 if (TREE_CODE (ctor) == TARGET_EXPR)
8775 ctor = TARGET_EXPR_INITIAL (ctor);
8776 if (TREE_CODE (ctor) == CONSTRUCTOR)
8777 {
8778 tree array = CONSTRUCTOR_ELT (ctor, 0)->value;
8779 array = extend_ref_init_temps_1 (decl, array, cleanups);
8780 CONSTRUCTOR_ELT (ctor, 0)->value = array;
8781 }
8782 }
8783 else if (TREE_CODE (init) == CONSTRUCTOR)
8784 {
8785 unsigned i;
8786 constructor_elt *p;
8787 VEC(constructor_elt,gc) *elts = CONSTRUCTOR_ELTS (init);
8788 FOR_EACH_VEC_ELT (constructor_elt, elts, i, p)
8789 p->value = extend_ref_init_temps (decl, p->value, cleanups);
8790 }
8791
8792 return init;
8793 }
8794
8795 /* Returns true iff TYPE is some variant of std::initializer_list. */
8796
8797 bool
8798 is_std_init_list (tree type)
8799 {
8800 /* Look through typedefs. */
8801 if (!TYPE_P (type))
8802 return false;
8803 type = TYPE_MAIN_VARIANT (type);
8804 return (CLASS_TYPE_P (type)
8805 && CP_TYPE_CONTEXT (type) == std_node
8806 && strcmp (TYPE_NAME_STRING (type), "initializer_list") == 0);
8807 }
8808
8809 /* Returns true iff DECL is a list constructor: i.e. a constructor which
8810 will accept an argument list of a single std::initializer_list<T>. */
8811
8812 bool
8813 is_list_ctor (tree decl)
8814 {
8815 tree args = FUNCTION_FIRST_USER_PARMTYPE (decl);
8816 tree arg;
8817
8818 if (!args || args == void_list_node)
8819 return false;
8820
8821 arg = non_reference (TREE_VALUE (args));
8822 if (!is_std_init_list (arg))
8823 return false;
8824
8825 args = TREE_CHAIN (args);
8826
8827 if (args && args != void_list_node && !TREE_PURPOSE (args))
8828 /* There are more non-defaulted parms. */
8829 return false;
8830
8831 return true;
8832 }
8833
8834 #include "gt-cp-call.h"