| blob | b7aa97cc947e8fa80dd99aef7cf2e8a89b861c43 |
1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2016 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) and
4 modified by Brendan Kehoe (brendan@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
23 /* High-level class interface. */
43 /* The various kinds of conversion. */
46 ck_identity,
47 ck_lvalue,
48 ck_fnptr,
49 ck_qual,
50 ck_std,
51 ck_ptr,
52 ck_pmem,
53 ck_base,
54 ck_ref_bind,
55 ck_user,
56 ck_ambig,
57 ck_list,
58 ck_aggr,
59 ck_rvalue
60 };
62 /* The rank of the conversion. Order of the enumerals matters; better
63 conversions should come earlier in the list. */
66 cr_identity,
67 cr_exact,
68 cr_promotion,
69 cr_std,
70 cr_pbool,
71 cr_user,
72 cr_ellipsis,
73 cr_bad
74 };
76 /* An implicit conversion sequence, in the sense of [over.best.ics].
77 The first conversion to be performed is at the end of the chain.
78 That conversion is always a cr_identity conversion. */
81 /* The kind of conversion represented by this step. */
82 conversion_kind kind;
83 /* The rank of this conversion. */
84 conversion_rank rank;
88 /* True if this conversion would be permitted with a bending of
89 language standards, e.g. disregarding pointer qualifiers or
90 converting integers to pointers. */
92 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
93 temporary should be created to hold the result of the
94 conversion. */
96 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
97 from a pointer-to-derived to pointer-to-base is being performed. */
99 /* If KIND is ck_ref_bind, true when either an lvalue reference is
100 being bound to an lvalue expression or an rvalue reference is
101 being bound to an rvalue expression. If KIND is ck_rvalue,
102 true when we should treat an lvalue as an rvalue (12.8p33). If
103 KIND is ck_base, always false. */
106 /* The type of the expression resulting from the conversion. */
107 tree type;
109 /* The next conversion in the chain. Since the conversions are
110 arranged from outermost to innermost, the NEXT conversion will
111 actually be performed before this conversion. This variant is
112 used only when KIND is neither ck_identity, ck_ambig nor
113 ck_list. Please use the next_conversion function instead
114 of using this field directly. */
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, so this
120 variant is used only when KIN D is ck_list. */
123 /* The function candidate corresponding to this conversion
124 sequence. This field is only used if KIND is ck_user. */
126 };
128 #define CONVERSION_RANK(NODE) \
129 ((NODE)->bad_p ? cr_bad \
130 : (NODE)->ellipsis_p ? cr_ellipsis \
131 : (NODE)->user_conv_p ? cr_user \
132 : (NODE)->rank)
134 #define BAD_CONVERSION_RANK(NODE) \
135 ((NODE)->ellipsis_p ? cr_ellipsis \
136 : (NODE)->user_conv_p ? cr_user \
137 : (NODE)->rank)
146 tsubst_flags_t);
149 #define convert_like(CONV, EXPR, COMPLAIN) \
150 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
153 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
154 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
162 tsubst_flags_t);
174 static void add_builtin_candidates
177 static void add_builtin_candidate
181 static void build_builtin_candidate
191 tsubst_flags_t);
193 tsubst_flags_t);
213 tsubst_flags_t);
217 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
218 NAME can take many forms... */
220 bool
222 {
223 /* Just accept something we've already complained about. */
232 {
238 else
240 }
241 else
242 {
243 /* In the case of:
245 template <class T> struct S { ~S(); };
246 int i;
247 i.~S();
249 NAME will be a class template. */
252 }
257 }
259 /* We want the address of a function or method. We avoid creating a
260 pointer-to-member function. */
262 tree
264 {
267 /* We have to do these by hand to avoid real pointer to member
268 functions. */
270 {
272 {
276 complain);
277 }
279 }
280 else
284 }
286 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
287 POINTER_TYPE to those. Note, pointer to member function types
288 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
289 two variants. build_call_a is the primitive taking an array of
290 arguments, while build_call_n is a wrapper that handles varargs. */
292 tree
294 {
297 else
298 {
308 }
309 }
311 /* Update various flags in cfun and the call itself based on what is being
312 called. Split out of build_call_a so that bot_manip can use it too. */
314 void
316 {
320 /* We check both the decl and the type; a function may be known not to
321 throw without being declared throw(). */
335 }
337 tree
339 {
340 tree decl;
341 tree result_type;
342 tree fntype;
352 /* An rvalue has no cv-qualifiers. */
363 {
364 /* We invoke build_call directly for several library
365 functions. These may have been declared normally if
366 we're building libgcc, so we can't just check
367 DECL_ARTIFICIAL. */
372 }
379 && flag_new_inheriting_ctors
383 /* Pass arguments directly to the inherited constructor. */
386 /* Don't pass empty class objects by value. This is useful
387 for tags in STL, which are used to control overload resolution.
388 We don't need to handle other cases of copying empty classes. */
391 {
395 {
399 }
400 }
403 }
405 /* New overloading code. */
412 };
414 /* Information for providing diagnostics about why overloading failed. */
417 rr_none,
418 rr_arity,
419 rr_explicit_conversion,
420 rr_template_conversion,
421 rr_arg_conversion,
422 rr_bad_arg_conversion,
423 rr_template_unification,
424 rr_invalid_copy,
425 rr_inherited_ctor,
426 rr_constraint_failure
427 };
430 /* The index of the argument, 0-based. */
432 /* The actual argument or its type. */
433 tree from;
434 /* The type of the parameter. */
435 tree to_type;
436 };
441 /* Information about an arity mismatch. */
443 /* The expected number of arguments. */
445 /* The actual number of arguments in the call. */
447 /* Whether the call was a varargs call. */
450 /* Information about an argument conversion mismatch. */
452 /* Same, but for bad argument conversions. */
454 /* Information about template unification failures. These are the
455 parameters passed to fn_type_unification. */
457 tree tmpl;
458 tree explicit_targs;
462 tree return_type;
463 unification_kind_t strict;
466 /* Information about template instantiation failures. These are the
467 parameters passed to instantiate_template. */
469 tree tmpl;
470 tree targs;
473 };
476 /* The FUNCTION_DECL that will be called if this candidate is
477 selected by overload resolution. */
478 tree fn;
479 /* If not NULL_TREE, the first argument to use when calling this
480 function. */
481 tree first_arg;
482 /* The rest of the arguments to use when calling this function. If
483 there are no further arguments this may be NULL or it may be an
484 empty vector. */
486 /* The implicit conversion sequences for each of the arguments to
487 FN. */
489 /* The number of implicit conversion sequences. */
491 /* If FN is a user-defined conversion, the standard conversion
492 sequence from the type returned by FN to the desired destination
493 type. */
496 /* If FN is a member function, the binfo indicating the path used to
497 qualify the name of FN at the call site. This path is used to
498 determine whether or not FN is accessible if it is selected by
499 overload resolution. The DECL_CONTEXT of FN will always be a
500 (possibly improper) base of this binfo. */
501 tree access_path;
502 /* If FN is a non-static member function, the binfo indicating the
503 subobject to which the `this' pointer should be converted if FN
504 is selected by overload resolution. The type pointed to by
505 the `this' pointer must correspond to the most derived class
506 indicated by the CONVERSION_PATH. */
507 tree conversion_path;
508 tree template_decl;
509 tree explicit_targs;
514 /* The flags active in add_candidate. */
516 };
518 /* Returns true iff T is a null pointer constant in the sense of
519 [conv.ptr]. */
521 bool
523 {
526 /* [conv.ptr]
528 A null pointer constant is an integral constant expression
529 (_expr.const_) rvalue of integer type that evaluates to zero or
530 an rvalue of type std::nullptr_t. */
535 {
536 /* Core issue 903 says only literal 0 is a null pointer constant. */
543 }
545 {
550 }
553 }
555 /* Returns true iff T is a null member pointer value (4.11). */
557 bool
559 {
568 else
570 }
572 /* Returns nonzero if PARMLIST consists of only default parms,
573 ellipsis, and/or undeduced parameter packs. */
575 bool
577 {
584 }
586 /* Allocate N bytes of memory from the conversion obstack. The memory
587 is zeroed before being returned. */
591 {
594 {
597 }
601 }
603 /* Allocate rejection reasons. */
607 {
612 }
616 {
622 }
626 {
633 }
637 {
644 }
648 {
654 }
658 {
664 }
671 {
678 /* Copy args to our own storage. */
686 }
690 {
692 }
696 {
699 }
703 {
706 }
708 // Build a constraint failure record, saving information into the
709 // template_instantiation field of the rejection. If FN is not a template
710 // declaration, the TMPL member is the FN declaration and TARGS is empty.
714 {
717 {
720 }
721 else
722 {
725 }
727 }
729 /* Dynamically allocate a conversion. */
733 {
738 }
740 /* Make sure that all memory on the conversion obstack has been
741 freed. */
743 void
745 {
749 }
751 /* Dynamically allocate an array of N conversions. */
755 {
757 }
761 {
765 /* Note that the caller is responsible for filling in t->cand for
766 user-defined conversions. */
772 {
789 }
795 }
797 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
798 specialization of std::initializer_list<T>, if such a conversion is
799 possible. */
803 {
809 tree val;
811 /* Within a list-initialization we can have more user-defined
812 conversions. */
814 /* But no narrowing conversions. */
817 /* Can't make an array of these types. */
824 {
825 conversion *sub
832 }
840 {
848 }
851 }
853 /* Return the next conversion of the conversion chain (if applicable),
854 or NULL otherwise. Please use this function instead of directly
855 accessing fields of struct conversion. */
859 {
866 }
868 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
869 is a valid aggregate initializer for array type ATYPE. */
871 static bool
873 {
877 {
883 else
885 complain);
888 }
890 }
892 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
893 aggregate class, if such a conversion is possible. */
897 {
903 /* We already called reshape_init in implicit_conversion. */
905 /* The conversions within the init-list aren't affected by the enclosing
906 context; they're always simple copy-initialization. */
910 {
912 tree val;
920 /* Value-initialization of reference is ill-formed. */
922 else
923 {
927 }
933 else
935 complain);
942 }
954 }
956 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
957 array type, if such a conversion is possible. */
961 {
966 tree val;
971 /* We might need to propagate the size from the element to the array. */
976 {
980 }
985 {
986 conversion *sub
998 }
1007 }
1009 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1010 complex type, if such a conversion is possible. */
1014 tsubst_flags_t complain)
1015 {
1020 tree val;
1031 {
1032 conversion *sub
1044 }
1053 }
1055 /* Build a representation of the identity conversion from EXPR to
1056 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1060 {
1068 }
1070 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1071 were multiple user-defined conversions to accomplish the job.
1072 Build a conversion that indicates that ambiguity. */
1076 {
1084 }
1086 tree
1088 {
1092 }
1094 /* Returns the standard conversion path (see [conv]) from type FROM to type
1095 TO, if any. For proper handling of null pointer constants, you must
1096 also pass the expression EXPR to convert from. If C_CAST_P is true,
1097 this conversion is coming from a C-style cast. */
1102 {
1106 tree qualified_to;
1110 {
1113 }
1119 {
1121 {
1127 }
1129 {
1130 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1133 }
1134 }
1141 {
1145 }
1146 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1147 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1148 express the copy constructor call required by copy-initialization. */
1150 {
1152 {
1153 tree bitfield_type;
1156 {
1159 }
1160 }
1164 }
1166 /* Allow conversion between `__complex__' data types. */
1168 {
1169 /* The standard conversion sequence to convert FROM to TO is
1170 the standard conversion sequence to perform componentwise
1171 conversion. */
1174 complain);
1177 {
1180 }
1181 else
1185 }
1188 {
1192 }
1194 /* [conv.ptr]
1195 A null pointer constant can be converted to a pointer type; ... A
1196 null pointer constant of integral type can be converted to an
1197 rvalue of type std::nullptr_t. */
1205 {
1206 /* For backwards brain damage compatibility, allow interconversion of
1207 pointers and integers with a pedwarn. */
1210 }
1212 {
1213 /* For backwards brain damage compatibility, allow interconversion of
1214 enums and integers with a pedwarn. */
1217 }
1220 {
1221 tree to_pointee;
1222 tree from_pointee;
1225 {
1229 /* Since this is the target of a pointer, it can't have function
1230 qualifiers, so any TYPE_QUALS must be for attributes const or
1231 noreturn. Strip them. */
1238 }
1239 else
1240 {
1243 }
1247 to_pointee))
1248 ;
1252 {
1254 /* Don't try to apply restrict to void. */
1259 }
1261 {
1266 && (same_type_ignoring_top_level_qualifiers_p
1268 {
1271 }
1274 }
1277 /* [conv.ptr]
1279 An rvalue of type "pointer to cv D," where D is a
1280 class type, can be converted to an rvalue of type
1281 "pointer to cv B," where B is a base class (clause
1282 _class.derived_) of D. If B is an inaccessible
1283 (clause _class.access_) or ambiguous
1284 (_class.member.lookup_) base class of D, a program
1285 that necessitates this conversion is ill-formed.
1286 Therefore, we use DERIVED_FROM_P, and do not check
1287 access or uniqueness. */
1289 {
1290 from_pointee
1296 }
1301 /* In a C-style cast, we ignore CV-qualification because we
1302 are allowed to perform a static_cast followed by a
1303 const_cast. */
1308 /* converting from string constant to char *. */
1312 /* Allow conversions among compatible ObjC pointer types (base
1313 conversions have been already handled above). */
1318 {
1321 }
1322 else
1326 }
1328 {
1342 else
1346 {
1348 tbase,
1354 }
1357 }
1359 {
1360 /* [conv.bool]
1362 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1363 to member type can be converted to a prvalue of type bool. ...
1364 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1365 std::nullptr_t can be converted to a prvalue of type bool; */
1371 {
1382 }
1385 }
1386 /* We don't check for ENUMERAL_TYPE here because there are no standard
1387 conversions to enum type. */
1388 /* As an extension, allow conversion to complex type. */
1390 {
1397 /* Give this a better rank if it's a promotion. */
1401 }
1407 {
1411 /* The derived-to-base conversion indicates the initialization
1412 of a parameter with base type from an object of a derived
1413 type. A temporary object is created to hold the result of
1414 the conversion unless we're binding directly to a reference. */
1416 }
1417 else
1424 }
1426 /* Returns nonzero if T1 is reference-related to T2. */
1428 bool
1430 {
1437 /* [dcl.init.ref]
1439 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1440 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1441 of T2. */
1445 }
1447 /* Returns nonzero if T1 is reference-compatible with T2. */
1449 static bool
1451 {
1452 /* [dcl.init.ref]
1454 "cv1 T1" is reference compatible with "cv2 T2" if
1455 * T1 is reference-related to T2 or
1456 * T2 is "noexcept function" and T1 is "function", where the
1457 function types are otherwise the same,
1458 and cv1 is the same cv-qualification as, or greater cv-qualification
1459 than, cv2. */
1463 }
1465 /* A reference of the indicated TYPE is being bound directly to the
1466 expression represented by the implicit conversion sequence CONV.
1467 Return a conversion sequence for this binding. */
1471 {
1472 tree t;
1479 /* [over.ics.rank]
1481 When a parameter of reference type binds directly
1482 (_dcl.init.ref_) to an argument expression, the implicit
1483 conversion sequence is the identity conversion, unless the
1484 argument expression has a type that is a derived class of the
1485 parameter type, in which case the implicit conversion sequence is
1486 a derived-to-base Conversion.
1488 If the parameter binds directly to the result of applying a
1489 conversion function to the argument expression, the implicit
1490 conversion sequence is a user-defined conversion sequence
1491 (_over.ics.user_), with the second standard conversion sequence
1492 either an identity conversion or, if the conversion function
1493 returns an entity of a type that is a derived class of the
1494 parameter type, a derived-to-base conversion. */
1496 {
1497 /* Represent the derived-to-base conversion. */
1499 /* We will actually be binding to the base-class subobject in
1500 the derived class, so we mark this conversion appropriately.
1501 That way, convert_like knows not to generate a temporary. */
1503 }
1505 }
1507 /* Returns the conversion path from type FROM to reference type TO for
1508 purposes of reference binding. For lvalue binding, either pass a
1509 reference type to FROM or an lvalue expression to EXPR. If the
1510 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1511 the conversion returned. If C_CAST_P is true, this
1512 conversion is coming from a C-style cast. */
1516 tsubst_flags_t complain)
1517 {
1521 tree tfrom;
1524 cp_lvalue_kind gl_kind;
1528 {
1533 }
1536 {
1538 /* DR 1288: Otherwise, if the initializer list has a single element
1539 of type E and ... [T's] referenced type is reference-related to E,
1540 the object or reference is initialized from that element... */
1542 {
1548 {
1552 }
1553 }
1554 /* Otherwise, if T is a reference type, a prvalue temporary of the
1555 type referenced by T is copy-list-initialized or
1556 direct-list-initialized, depending on the kind of initialization
1557 for the reference, and the reference is bound to that temporary. */
1560 skip:;
1561 }
1564 {
1569 else
1571 }
1577 else
1580 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1585 /* Same mask as real_lvalue_p. */
1592 /* Figure out whether or not the types are reference-related and
1593 reference compatible. We have to do this after stripping
1594 references from FROM. */
1596 /* If this is a C cast, first convert to an appropriately qualified
1597 type, so that we can later do a const_cast to the desired type. */
1603 /* Directly bind reference when target expression's type is compatible with
1604 the reference and expression is an lvalue. In DR391, the wording in
1605 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1606 const and rvalue references to rvalues of compatible class type.
1607 We should also do direct bindings for non-class xvalues. */
1609 {
1610 /* [dcl.init.ref]
1612 If the initializer expression
1614 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1615 is reference-compatible with "cv2 T2,"
1617 the reference is bound directly to the initializer expression
1618 lvalue.
1620 [...]
1621 If the initializer expression is an rvalue, with T2 a class type,
1622 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1623 is bound to the object represented by the rvalue or to a sub-object
1624 within that object. */
1630 /* The top-level caller requested that we pretend that the lvalue
1631 be treated as an rvalue. */
1634 /* Handle rvalue reference to function properly. */
1635 conv->rvaluedness_matches_p
1637 else
1638 conv->rvaluedness_matches_p
1643 /* For the purposes of overload resolution, we ignore the fact
1644 this expression is a bitfield or packed field. (In particular,
1645 [over.ics.ref] says specifically that a function with a
1646 non-const reference parameter is viable even if the
1647 argument is a bitfield.)
1649 However, when we actually call the function we must create
1650 a temporary to which to bind the reference. If the
1651 reference is volatile, or isn't const, then we cannot make
1652 a temporary, so we just issue an error when the conversion
1653 actually occurs. */
1656 /* Don't allow binding of lvalues (other than function lvalues) to
1657 rvalue references. */
1663 /* Nor the reverse. */
1674 }
1675 /* [class.conv.fct] A conversion function is never used to convert a
1676 (possibly cv-qualified) object to the (possibly cv-qualified) same
1677 object type (or a reference to it), to a (possibly cv-qualified) base
1678 class of that type (or a reference to it).... */
1681 {
1682 /* [dcl.init.ref]
1684 If the initializer expression
1686 -- has a class type (i.e., T2 is a class type) can be
1687 implicitly converted to an lvalue of type "cv3 T3," where
1688 "cv1 T1" is reference-compatible with "cv3 T3". (this
1689 conversion is selected by enumerating the applicable
1690 conversion functions (_over.match.ref_) and choosing the
1691 best one through overload resolution. (_over.match_).
1693 the reference is bound to the lvalue result of the conversion
1694 in the second case. */
1696 complain);
1699 }
1701 /* From this point on, we conceptually need temporaries, even if we
1702 elide them. Only the cases above are "direct bindings". */
1706 /* [over.ics.rank]
1708 When a parameter of reference type is not bound directly to an
1709 argument expression, the conversion sequence is the one required
1710 to convert the argument expression to the underlying type of the
1711 reference according to _over.best.ics_. Conceptually, this
1712 conversion sequence corresponds to copy-initializing a temporary
1713 of the underlying type with the argument expression. Any
1714 difference in top-level cv-qualification is subsumed by the
1715 initialization itself and does not constitute a conversion. */
1717 /* [dcl.init.ref]
1719 Otherwise, the reference shall be an lvalue reference to a
1720 non-volatile const type, or the reference shall be an rvalue
1721 reference.
1723 We try below to treat this as a bad conversion to improve diagnostics,
1724 but if TO is an incomplete class, we need to reject this conversion
1725 now to avoid unnecessary instantiation. */
1730 /* We're generating a temporary now, but don't bind any more in the
1731 conversion (specifically, don't slice the temporary returned by a
1732 conversion operator). */
1735 /* Core issue 899: When [copy-]initializing a temporary to be bound
1736 to the first parameter of a copy constructor (12.8) called with
1737 a single argument in the context of direct-initialization,
1738 explicit conversion functions are also considered.
1740 So don't set LOOKUP_ONLYCONVERTING in that case. */
1751 {
1752 /* If initializing the temporary used a conversion function,
1753 recalculate the second conversion sequence. */
1757 {
1760 conversion *new_second
1766 }
1767 }
1770 /* This reference binding, unlike those above, requires the
1771 creation of a temporary. */
1775 /* [dcl.init.ref]
1777 Otherwise, the reference shall be an lvalue reference to a
1778 non-volatile const type, or the reference shall be an rvalue
1779 reference. */
1783 /* [dcl.init.ref]
1785 Otherwise, a temporary of type "cv1 T1" is created and
1786 initialized from the initializer expression using the rules for a
1787 non-reference copy initialization. If T1 is reference-related to
1788 T2, cv1 must be the same cv-qualification as, or greater
1789 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1794 }
1796 /* Returns the implicit conversion sequence (see [over.ics]) from type
1797 FROM to type TO. The optional expression EXPR may affect the
1798 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1799 true, this conversion is coming from a C-style cast. */
1804 {
1811 /* Other flags only apply to the primary function in overload
1812 resolution, or after we've chosen one. */
1817 /* FIXME: actually we don't want warnings either, but we can't just
1818 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1819 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1820 We really ought not to issue that warning until we've committed
1821 to that conversion. */
1824 /* Call reshape_init early to remove redundant braces. */
1829 {
1834 }
1838 else
1845 {
1849 /* As an extension, allow list-initialization of _Complex. */
1851 {
1855 }
1857 /* Allow conversion from an initializer-list with one element to a
1858 scalar type. */
1860 {
1862 tree elt;
1868 else
1874 {
1877 /* Too many levels of braces, i.e. '{{1}}'. */
1880 }
1881 }
1884 }
1890 {
1900 {
1904 {
1905 /* "If C is not an initializer-list constructor and the
1906 initializer list has a single element of type cv U, where U is
1907 X or a class derived from X, the implicit conversion sequence
1908 has Exact Match rank if U is X, or Conversion rank if U is
1909 derived from X." */
1915 }
1917 }
1919 /* We used to try to bind a reference to a temporary here, but that
1920 is now handled after the recursive call to this function at the end
1921 of reference_binding. */
1923 }
1926 }
1928 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1929 functions. ARGS will not be changed until a single candidate is
1930 selected. */
1939 {
1957 }
1959 /* Return the number of remaining arguments in the parameter list
1960 beginning with ARG. */
1962 int
1964 {
1969 n++;
1972 }
1974 /* Create an overload candidate for the function or method FN called
1975 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1976 FLAGS is passed on to implicit_conversion.
1978 This does not change ARGS.
1980 CTYPE, if non-NULL, is the type we want to pretend this function
1981 comes from for purposes of overload resolution. */
1988 tsubst_flags_t complain)
1989 {
1993 tree parmnode;
1999 /* At this point we should not see any functions which haven't been
2000 explicitly declared, except for friend functions which will have
2001 been found using argument dependent lookup. */
2004 /* The `this', `in_chrg' and VTT arguments to constructors are not
2005 considered in overload resolution. */
2007 {
2011 {
2014 }
2015 }
2016 else
2022 /* 13.3.2 - Viable functions [over.match.viable]
2023 First, to be a viable function, a candidate function shall have enough
2024 parameters to agree in number with the arguments in the list.
2026 We need to check this first; otherwise, checking the ICSes might cause
2027 us to produce an ill-formed template instantiation. */
2031 {
2035 }
2039 {
2043 }
2045 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2046 parameter of type "reference to cv C" (including such a constructor
2047 instantiated from a template) is excluded from the set of candidate
2048 functions when used to construct an object of type D with an argument list
2049 containing a single argument if C is reference-related to D. */
2051 && flag_new_inheriting_ctors
2053 {
2057 {
2060 }
2061 }
2063 /* Second, for a function to be viable, its constraints must be
2064 satisfied. */
2067 {
2070 }
2072 /* When looking for a function from a subobject from an implicit
2073 copy/move constructor/operator=, don't consider anything that takes (a
2074 reference to) an unrelated type. See c++/44909 and core 1092. */
2076 {
2082 else
2085 {
2088 ctype))
2090 }
2092 /* This only applies at the top level. */
2094 }
2099 /* Third, for F to be a viable function, there shall exist for each
2100 argument an implicit conversion sequence that converts that argument
2101 to the corresponding parameter of F. */
2106 {
2108 tree arg;
2117 else
2126 {
2132 /* The type of the implicit object parameter ('this') for
2133 overload resolution is not always the same as for the
2134 function itself; conversion functions are considered to
2135 be members of the class being converted, and functions
2136 introduced by a using-declaration are considered to be
2137 members of the class that uses them.
2139 Since build_over_call ignores the ICS for the `this'
2140 parameter, we can just change the parm type. */
2142 {
2143 parmtype = cp_build_qualified_type
2146 {
2147 /* If the function has a ref-qualifier, the implicit
2148 object parameter has reference type. */
2151 /* The special handling of 'this' conversions in compare_ics
2152 does not apply if there is a ref-qualifier. */
2154 }
2155 else
2156 {
2160 }
2161 }
2163 /* Core issue 899: When [copy-]initializing a temporary to be bound
2164 to the first parameter of a copy constructor (12.8) called with
2165 a single argument in the context of direct-initialization,
2166 explicit conversion functions are also considered.
2168 So set LOOKUP_COPY_PARM to let reference_binding know that
2169 it's being called in that context. We generalize the above
2170 to handle move constructors and template constructors as well;
2171 the standardese should soon be updated similarly. */
2175 && (same_type_ignoring_top_level_qualifiers_p
2177 {
2180 /* We allow user-defined conversions within init-lists, but
2181 don't list-initialize the copy parm, as that would mean
2182 using two levels of braces for the same type. */
2186 }
2187 else
2193 }
2194 else
2195 {
2199 }
2206 {
2210 }
2213 {
2216 }
2217 }
2219 out:
2222 }
2224 /* Create an overload candidate for the conversion function FN which will
2225 be invoked for expression OBJ, producing a pointer-to-function which
2226 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2227 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2228 passed on to implicit_conversion.
2230 Actually, we don't really care about FN; we care about the type it
2231 converts to. There may be multiple conversion functions that will
2232 convert to that type, and we rely on build_user_type_conversion_1 to
2233 choose the best one; so when we create our candidate, we record the type
2234 instead of the function. */
2240 tsubst_flags_t complain)
2241 {
2259 /* Don't bother looking up the same type twice. */
2264 {
2270 else
2275 {
2279 }
2283 {
2287 }
2288 else
2289 {
2293 }
2300 {
2303 }
2310 }
2314 {
2318 }
2322 }
2324 static void
2328 {
2342 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2343 conversion ops are allowed. We handle that here by just checking for
2344 boolean_type_node because other operators don't ask for it. COND_EXPR
2345 also does contextual conversion to bool for the first operand, but we
2346 handle that in build_conditional_expr, and type1 here is operand 2. */
2351 {
2358 {
2360 /* We need something for printing the candidate. */
2364 }
2366 {
2370 }
2372 }
2374 /* For COND_EXPR we rearranged the arguments; undo that now. */
2376 {
2381 complain);
2384 else
2385 {
2388 boolean_type_node);
2389 }
2390 }
2397 }
2399 static bool
2401 {
2403 }
2405 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2407 static bool
2409 {
2410 /* [over.built]
2412 In this section, the term promoted integral type is used to refer
2413 to those integral types which are preserved by integral promotion
2414 (including e.g. int and long but excluding e.g. char).
2415 Similarly, the term promoted arithmetic type refers to promoted
2416 integral types plus floating types. */
2420 }
2422 /* Create any builtin operator overload candidates for the operator in
2423 question given the converted operand types TYPE1 and TYPE2. The other
2424 args are passed through from add_builtin_candidates to
2425 build_builtin_candidate.
2427 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2428 If CODE is requires candidates operands of the same type of the kind
2429 of which TYPE1 and TYPE2 are, we add both candidates
2430 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2432 static void
2436 tsubst_flags_t complain)
2437 {
2439 {
2447 }
2450 {
2452 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2453 and VQ is either volatile or empty, there exist candidate operator
2454 functions of the form
2455 VQ T& operator++(VQ T&);
2456 T operator++(VQ T&, int);
2457 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2458 type other than bool, and VQ is either volatile or empty, there exist
2459 candidate operator functions of the form
2460 VQ T& operator--(VQ T&);
2461 T operator--(VQ T&, int);
2462 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2463 complete object type, and VQ is either volatile or empty, there exist
2464 candidate operator functions of the form
2465 T*VQ& operator++(T*VQ&);
2466 T*VQ& operator--(T*VQ&);
2467 T* operator++(T*VQ&, int);
2468 T* operator--(T*VQ&, int); */
2474 /* FALLTHRU */
2478 {
2481 }
2484 /* 7 For every cv-qualified or cv-unqualified object type T, there
2485 exist candidate operator functions of the form
2487 T& operator*(T*);
2489 8 For every function type T, there exist candidate operator functions of
2490 the form
2491 T& operator*(T*); */
2500 /* 9 For every type T, there exist candidate operator functions of the form
2501 T* operator+(T*);
2503 10For every promoted arithmetic type T, there exist candidate operator
2504 functions of the form
2505 T operator+(T);
2506 T operator-(T); */
2511 /* FALLTHRU */
2517 /* 11For every promoted integral type T, there exist candidate operator
2518 functions of the form
2519 T operator~(T); */
2526 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2527 is the same type as C2 or is a derived class of C2, T is a complete
2528 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2529 there exist candidate operator functions of the form
2530 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2531 where CV12 is the union of CV1 and CV2. */
2535 {
2543 }
2546 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2547 didate operator functions of the form
2548 LR operator*(L, R);
2549 LR operator/(L, R);
2550 LR operator+(L, R);
2551 LR operator-(L, R);
2552 bool operator<(L, R);
2553 bool operator>(L, R);
2554 bool operator<=(L, R);
2555 bool operator>=(L, R);
2556 bool operator==(L, R);
2557 bool operator!=(L, R);
2558 where LR is the result of the usual arithmetic conversions between
2559 types L and R.
2561 14For every pair of types T and I, where T is a cv-qualified or cv-
2562 unqualified complete object type and I is a promoted integral type,
2563 there exist candidate operator functions of the form
2564 T* operator+(T*, I);
2565 T& operator[](T*, I);
2566 T* operator-(T*, I);
2567 T* operator+(I, T*);
2568 T& operator[](I, T*);
2570 15For every T, where T is a pointer to complete object type, there exist
2571 candidate operator functions of the form112)
2572 ptrdiff_t operator-(T, T);
2574 16For every pointer or enumeration type T, there exist candidate operator
2575 functions of the form
2576 bool operator<(T, T);
2577 bool operator>(T, T);
2578 bool operator<=(T, T);
2579 bool operator>=(T, T);
2580 bool operator==(T, T);
2581 bool operator!=(T, T);
2583 17For every pointer to member type T, there exist candidate operator
2584 functions of the form
2585 bool operator==(T, T);
2586 bool operator!=(T, T); */
2593 {
2596 }
2597 /* FALLTHRU */
2610 {
2613 }
2615 {
2618 }
2619 /* Fall through. */
2635 {
2638 }
2641 {
2644 }
2650 /* FALLTHRU */
2653 {
2656 }
2658 {
2661 }
2664 /* 18For every pair of promoted integral types L and R, there exist candi-
2665 date operator functions of the form
2666 LR operator%(L, R);
2667 LR operator&(L, R);
2668 LR operator^(L, R);
2669 LR operator|(L, R);
2670 L operator<<(L, R);
2671 L operator>>(L, R);
2672 where LR is the result of the usual arithmetic conversions between
2673 types L and R. */
2681 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2685 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2686 type, VQ is either volatile or empty, and R is a promoted arithmetic
2687 type, there exist candidate operator functions of the form
2688 VQ L& operator=(VQ L&, R);
2689 VQ L& operator*=(VQ L&, R);
2690 VQ L& operator/=(VQ L&, R);
2691 VQ L& operator+=(VQ L&, R);
2692 VQ L& operator-=(VQ L&, R);
2694 20For every pair T, VQ), where T is any type and VQ is either volatile
2695 or empty, there exist candidate operator functions of the form
2696 T*VQ& operator=(T*VQ&, T*);
2698 21For every pair T, VQ), where T is a pointer to member type and VQ is
2699 either volatile or empty, there exist candidate operator functions of
2700 the form
2701 VQ T& operator=(VQ T&, T);
2703 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2704 unqualified complete object type, VQ is either volatile or empty, and
2705 I is a promoted integral type, there exist candidate operator func-
2706 tions of the form
2707 T*VQ& operator+=(T*VQ&, I);
2708 T*VQ& operator-=(T*VQ&, I);
2710 23For every triple L, VQ, R), where L is an integral or enumeration
2711 type, VQ is either volatile or empty, and R is a promoted integral
2712 type, there exist candidate operator functions of the form
2714 VQ L& operator%=(VQ L&, R);
2715 VQ L& operator<<=(VQ L&, R);
2716 VQ L& operator>>=(VQ L&, R);
2717 VQ L& operator&=(VQ L&, R);
2718 VQ L& operator^=(VQ L&, R);
2719 VQ L& operator|=(VQ L&, R); */
2723 {
2727 {
2730 }
2731 /* FALLTHRU */
2744 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2757 {
2760 }
2765 }
2770 /* [over.built]
2772 For every pair of promoted arithmetic types L and R, there
2773 exist candidate operator functions of the form
2775 LR operator?(bool, L, R);
2777 where LR is the result of the usual arithmetic conversions
2778 between types L and R.
2780 For every type T, where T is a pointer or pointer-to-member
2781 type, there exist candidate operator functions of the form T
2782 operator?(bool, T, T); */
2786 /* That's OK. */
2789 /* Otherwise, the types should be pointers. */
2793 /* We don't check that the two types are the same; the logic
2794 below will actually create two candidates; one in which both
2795 parameter types are TYPE1, and one in which both parameter
2796 types are TYPE2. */
2807 }
2809 /* Make sure we don't create builtin candidates with dependent types. */
2813 {
2814 /* Try to recover if one of the types is non-dependent. But if
2815 there's only one type, there's nothing we can do. */
2818 /* And we lose if both are dependent. */
2821 /* Or if they have different forms. */
2829 }
2831 /* If we're dealing with two pointer types or two enumeral types,
2832 we need candidates for both of them. */
2841 {
2843 {
2845 error_mark_node,
2846 error_mark_node,
2847 CPO_CONVERSION,
2848 tf_none);
2850 {
2851 build_builtin_candidate
2855 }
2856 }
2858 build_builtin_candidate
2860 build_builtin_candidate
2863 }
2865 build_builtin_candidate
2867 }
2869 tree
2871 {
2877 }
2879 /* There are three conditions of builtin candidates:
2881 1) bool-taking candidates. These are the same regardless of the input.
2882 2) pointer-pair taking candidates. These are generated for each type
2883 one of the input types converts to.
2884 3) arithmetic candidates. According to the standard, we should generate
2885 all of these, but I'm trying not to...
2887 Here we generate a superset of the possible candidates for this particular
2888 case. That is a subset of the full set the standard defines, plus some
2889 other cases which the standard disallows. add_builtin_candidate will
2890 filter out the invalid set. */
2892 static void
2896 {
2900 /* TYPES[i] is the set of possible builtin-operator parameter types
2901 we will consider for the Ith argument. */
2906 {
2909 else
2911 }
2914 {
2915 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2916 and VQ is either volatile or empty, there exist candidate operator
2917 functions of the form
2918 VQ T& operator++(VQ T&); */
2928 /* 24There also exist candidate operator functions of the form
2929 bool operator!(bool);
2930 bool operator&&(bool, bool);
2931 bool operator||(bool, bool); */
2934 build_builtin_candidate
2941 build_builtin_candidate
2959 /* Fall through. */
2963 }
2969 {
2971 ;
2973 {
2974 tree convs;
2982 {
2987 }
2993 {
3006 {
3012 }
3016 }
3017 }
3018 else
3019 {
3024 {
3030 }
3032 }
3033 }
3035 /* Run through the possible parameter types of both arguments,
3036 creating candidates with those parameter types. */
3038 {
3040 tree u;
3044 add_builtin_candidate
3047 else
3048 add_builtin_candidate
3051 }
3055 }
3058 /* If TMPL can be successfully instantiated as indicated by
3059 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3061 TMPL is the template. EXPLICIT_TARGS are any explicit template
3062 arguments. ARGLIST is the arguments provided at the call-site.
3063 This does not change ARGLIST. The RETURN_TYPE is the desired type
3064 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3065 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3066 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3074 tsubst_flags_t complain)
3075 {
3085 tree arg;
3087 tree fn;
3091 /* We don't do deduction on the in-charge parameter, the VTT
3092 parameter or 'this'. */
3094 {
3098 /* We're deducing for a call to the result of a template conversion
3100 else
3102 }
3107 {
3110 else
3112 }
3120 {
3121 /* 12.8/6 says, "A declaration of a constructor for a class X is
3122 ill-formed if its first parameter is of type (optionally cv-qualified)
3123 X and either there are no other parameters or else all other
3124 parameters have default arguments. A member function template is never
3125 instantiated to produce such a constructor signature."
3127 So if we're trying to copy an object of the containing class, don't
3128 consider a template constructor that has a first parameter type that
3129 is just a template parameter, as we would deduce a signature that we
3130 would then reject in the code below. */
3132 {
3137 {
3141 }
3142 }
3143 }
3150 {
3153 }
3157 {
3160 }
3165 args_without_in_chrg,
3166 nargs_without_in_chrg,
3171 {
3172 /* Don't repeat unification later if it already resulted in errors. */
3176 nargs_without_in_chrg,
3178 else
3181 }
3184 {
3187 ctype))
3188 {
3189 /* We're trying to produce a constructor with a prohibited signature,
3190 as discussed above; handle here any cases we didn't catch then,
3191 such as X(X<T>). */
3194 }
3195 }
3198 /* Aha, this is a conversion function. */
3201 else
3206 /* This situation can occur if a member template of a template
3207 class is specialized. Then, instantiate_template might return
3208 an instantiation of the specialization, in which case the
3209 DECL_TI_TEMPLATE field will point at the original
3210 specialization. For example:
3212 template <class T> struct S { template <class U> void f(U);
3213 template <> void f(int) {}; };
3214 S<double> sd;
3215 sd.f(3);
3217 Here, TMPL will be template <class U> S<double>::f(U).
3218 And, instantiate template will give us the specialization
3219 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3220 for this will point at template <class T> template <> S<T>::f(int),
3221 so that we can find the definition. For the purposes of
3222 overload resolution, however, we want the original TMPL. */
3224 else
3229 fail:
3232 }
3241 {
3242 return
3247 }
3249 /* Create an overload candidate for the conversion function template TMPL,
3250 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3251 pointer-to-function which will in turn be called with the argument list
3252 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3253 passed on to implicit_conversion. */
3257 tree obj,
3261 {
3262 /* Making this work broke PR 71117, so until the committee resolves core
3263 issue 2189, let's disable this candidate if there are any viable call
3264 operators. */
3268 return
3272 complain);
3273 }
3275 /* The CANDS are the set of candidates that were considered for
3276 overload resolution. Return the set of viable candidates, or CANDS
3277 if none are viable. If any of the candidates were viable, set
3278 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3279 considered viable only if it is strictly viable. */
3285 {
3291 /* Be strict inside templates, since build_over_call won't actually
3292 do the conversions to get pedwarns. */
3302 {
3306 {
3307 /* Be strict in the presence of a viable candidate. Also if
3308 there are template candidates, so that we get deduction errors
3309 for them instead of silently preferring a bad conversion. */
3312 {
3313 /* Put any spliced near matches back onto the main list so
3314 that we see them if there is no strict match. */
3320 }
3321 }
3324 {
3332 }
3333 else
3335 }
3338 }
3340 static bool
3342 {
3347 }
3349 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3350 words, it is about to become the "this" pointer for a member
3351 function call. Take the address of the object. */
3353 static tree
3355 {
3356 /* In a template, we are only concerned about the type of the
3357 expression, so we can take a shortcut. */
3362 }
3364 /* Returns true iff functions are equivalent. Equivalent functions are
3365 not '==' only if one is a function-local extern function or if
3366 both are extern "C". */
3370 {
3379 }
3381 /* Print information about a candidate being rejected due to INFO. */
3383 static void
3385 {
3390 {
3391 /* Conversion of implicit `this' argument failed. */
3393 /* A bad conversion for 'this' must be discarding cv-quals. */
3396 from);
3397 else
3401 }
3403 {
3408 tf_warning_or_error);
3409 }
3411 /* Conversion of conversion function return value failed. */
3414 else
3417 }
3419 /* Print information about a candidate with WANT parameters and we found
3420 HAVE. */
3422 static void
3424 {
3429 }
3431 /* Print information about one overload candidate CANDIDATE. MSGSTR
3432 is the text to print before the candidate itself.
3434 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3435 to have been run through gettext by the caller. This wart makes
3436 life simpler in print_z_candidates and for the translators. */
3438 static void
3441 {
3451 {
3462 else
3465 }
3472 else
3475 {
3478 }
3479 /* Give the user some information about why this candidate failed. */
3481 {
3485 {
3498 "cannot be converted to %qT with a qualification "
3504 "conversion function specialization to %qT is not an "
3509 /* We use template_unification_error_rejection if unification caused
3510 actual non-SFINAE errors, in which case we don't need to repeat
3511 them here. */
3513 {
3517 }
3518 /* Re-run template unification with diagnostics. */
3522 (make_tree_vec
3533 " a constructor taking a single argument of its own "
3537 {
3541 }
3545 "initialization from an expression of the same or derived "
3550 /* This candidate didn't have any issues or we failed to
3551 handle a particular code. Either way... */
3553 }
3554 }
3555 }
3557 static void
3559 {
3566 /* Remove non-viable deleted candidates. */
3569 {
3574 else
3576 }
3577 /* ...if there are any non-deleted ones. */
3581 /* There may be duplicates in the set of candidates. We put off
3582 checking this condition as long as possible, since we have no way
3583 to eliminate duplicates from a set of functions in less than n^2
3584 time. Now we are about to emit an error message, so it is more
3585 permissible to go slowly. */
3587 {
3589 /* Skip builtin candidates and conversion functions. */
3594 {
3598 else
3600 }
3601 }
3605 }
3607 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3608 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3609 the result of the conversion function to convert it to the final
3610 desired type. Merge the two sequences into a single sequence,
3611 and return the merged sequence. */
3615 {
3621 /* Find the end of the second conversion sequence. */
3623 {
3624 /* The entire sequence is a user-conversion sequence. */
3628 }
3630 /* Replace the identity conversion with the user conversion
3631 sequence. */
3635 }
3637 /* Handle overload resolution for initializing an object of class type from
3638 an initializer list. First we look for a suitable constructor that
3639 takes a std::initializer_list; if we don't find one, we then look for a
3640 non-list constructor.
3642 Parameters are as for add_candidates, except that the arguments are in
3643 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3644 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3646 static void
3653 tsubst_flags_t complain)
3654 {
3657 /* We're looking for a ctor for list-initialization. */
3659 /* And we don't allow narrowing conversions. We also use this flag to
3660 avoid the copy constructor call for copy-list-initialization. */
3666 /* Always use the default constructor if the list is empty (DR 990). */
3669 ;
3670 /* If the class has a list ctor, try passing the list as a single
3671 argument first, but only consider list ctors. */
3673 {
3680 }
3682 /* Expand the CONSTRUCTOR into a new argument vec. */
3690 /* We aren't looking for list-ctors anymore. */
3692 /* We allow more user-defined conversions within an init-list. */
3698 }
3700 /* Returns the best overload candidate to perform the requested
3701 conversion. This function is used for three the overloading situations
3702 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3703 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3704 per [dcl.init.ref], so we ignore temporary bindings. */
3708 tsubst_flags_t complain)
3709 {
3711 tree fromtype;
3725 /* We represent conversion within a hierarchy using RVALUE_CONV and
3726 BASE_CONV, as specified by [over.best.ics]; these become plain
3727 constructor calls, as specified in [dcl.init]. */
3732 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3733 creating a garbage BASELINK; constructors can't be inherited. */
3736 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3737 a single element. For now, let's handle constructors as before and also
3738 consider conversion operators from the element. */
3745 {
3750 {
3751 /* [class.conv.fct] A conversion function is never used to
3752 convert a (possibly cv-qualified) object to the (possibly
3753 cv-qualified) same object type (or a reference to it), to a
3754 (possibly cv-qualified) base class of that type (or a
3755 reference to it)... */
3756 }
3757 else
3759 }
3766 /* It's OK to bind a temporary for converting constructor arguments, but
3767 not in converting the return value of a conversion operator. */
3773 {
3778 /* We should never try to call the abstract or base constructor
3779 from here. */
3785 {
3786 /* List-initialization. */
3790 }
3791 else
3792 {
3796 }
3799 {
3802 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3803 set, then this is copy-initialization. In that case, "The
3804 result of the call is then used to direct-initialize the
3805 object that is the destination of the copy-initialization."
3806 [dcl.init]
3808 We represent this in the conversion sequence with an
3809 rvalue conversion, which means a constructor call. */
3812 cand->second_conv
3814 }
3815 }
3818 {
3820 /* FIXME see above about C++17. */
3822 else
3824 }
3827 {
3831 /* If we are called to convert to a reference type, we are trying to
3832 find a direct binding, so don't even consider temporaries. If
3833 we don't find a direct binding, the caller will try again to
3834 look for a temporary binding. */
3845 {
3847 conversion *ics
3849 rettype,
3852 complain);
3854 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3855 copy-initialization. In that case, "The result of the
3856 call is then used to direct-initialize the object that is
3857 the destination of the copy-initialization." [dcl.init]
3859 We represent this in the conversion sequence with an
3860 rvalue conversion, which means a constructor call. But
3861 don't add a second rvalue conversion if there's already
3862 one there. Which there really shouldn't be, but it's
3863 harmless since we'd add it here anyway. */
3871 {
3875 }
3878 {
3879 /* 13.3.1.5: For direct-initialization, those explicit
3880 conversion functions that are not hidden within S and
3881 yield type T or a type that can be converted to type T
3882 with a qualification conversion (4.4) are also candidate
3883 functions. */
3884 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3885 I've raised this issue with the committee. --jason 9/2011 */
3888 }
3890 {
3892 cand->reason
3895 }
3898 {
3899 /* 13.3.3.1.2: If the user-defined conversion is specified by
3900 a specialization of a conversion function template, the
3901 second standard conversion sequence shall have exact match
3902 rank. */
3905 }
3906 }
3907 }
3911 {
3915 }
3919 {
3921 {
3925 }
3932 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3933 ambiguous conversion is no worse than another user-defined
3934 conversion. */
3937 }
3939 tree convtype;
3943 /* DR 5: [in the first step of copy-initialization]...if the function
3944 is a constructor, the call initializes a temporary of the
3945 cv-unqualified version of the destination type. */
3947 else
3949 /* Build the user conversion sequence. */
3950 conv = build_conv
3952 convtype,
3958 /* Remember that this was a list-initialization. */
3962 /* Combine it with the second conversion sequence. */
3967 }
3969 /* Wrapper for above. */
3971 tree
3973 tsubst_flags_t complain)
3974 {
3976 tree ret;
3982 {
3985 else
3986 {
3989 }
3990 }
3991 else
3996 }
3998 /* Subroutine of convert_nontype_argument.
4000 EXPR is an argument for a template non-type parameter of integral or
4001 enumeration type. Do any necessary conversions (that are permitted for
4002 non-type arguments) to convert it to the parameter type.
4004 If conversion is successful, returns the converted expression;
4005 otherwise, returns error_mark_node. */
4007 tree
4009 {
4012 tree t;
4020 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4027 /* for a non-type template-parameter of integral or
4028 enumeration type, integral promotions (4.5) and integral
4029 conversions (4.7) are applied. */
4030 /* It should be sufficient to check the outermost conversion step, since
4031 there are no qualification conversions to integer type. */
4034 {
4035 /* A conversion function is OK. If it isn't constexpr, we'll
4036 complain later that the argument isn't constant. */
4038 /* The lvalue-to-rvalue conversion is OK. */
4051 /* fall through. */
4056 }
4060 else
4063 /* Free all the conversions we allocated. */
4067 }
4069 /* Do any initial processing on the arguments to a function call. */
4073 {
4075 tree arg;
4078 {
4082 {
4086 }
4089 }
4091 }
4093 /* Perform overload resolution on FN, which is called with the ARGS.
4095 Return the candidate function selected by overload resolution, or
4096 NULL if the event that overload resolution failed. In the case
4097 that overload resolution fails, *CANDIDATES will be the set of
4098 candidates considered, and ANY_VIABLE_P will be set to true or
4099 false to indicate whether or not any of the candidates were
4100 viable.
4102 The ARGS should already have gone through RESOLVE_ARGS before this
4103 function is called. */
4110 {
4112 tree explicit_targs;
4123 /* Check FN. */
4130 {
4134 }
4136 /* Add the various candidate functions. */
4141 LOOKUP_NORMAL,
4147 else
4152 }
4154 /* Print an error message about being unable to build a call to FN with
4155 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4156 be located; CANDIDATES is a possibly empty list of such
4157 functions. */
4159 static void
4162 {
4165 {
4168 }
4177 else
4182 }
4184 /* Return an expression for a call to FN (a namespace-scope function,
4185 or a static member function) with the ARGS. This may change
4186 ARGS. */
4188 tree
4190 tsubst_flags_t complain)
4191 {
4195 tree result;
4198 {
4202 }
4207 /* If this function was found without using argument dependent
4208 lookup, then we want to ignore any undeclared friend
4209 functions. */
4211 {
4216 {
4220 }
4221 }
4223 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4227 complain);
4230 {
4232 {
4233 // If there is a single (non-viable) function candidate,
4234 // let the error be diagnosed by cp_build_function_call_vec.
4239 // Otherwise, emit notes for non-viable candidates.
4241 }
4243 }
4244 else
4245 {
4247 /* If fn is template_id_expr, the call has explicit template arguments
4248 (e.g. func<int>(5)), communicate this info to build_over_call
4249 through flags so that later we can use it to decide whether to warn
4250 about peculiar null pointer conversion. */
4252 {
4253 /* If overload resolution selects a specialization of a
4254 function concept for non-dependent template arguments,
4255 the expression is true if the constraints are satisfied
4256 and false otherwise.
4258 NOTE: This is an extension of Concepts Lite TS that
4259 allows constraints to be used in expressions. */
4261 {
4267 }
4270 }
4273 }
4275 /* Free all the conversions we allocated. */
4279 }
4281 /* Build a call to a global operator new. FNNAME is the name of the
4282 operator (either "operator new" or "operator new[]") and ARGS are
4283 the arguments provided. This may change ARGS. *SIZE points to the
4284 total number of bytes required by the allocation, and is updated if
4285 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4286 be used. If this function determines that no cookie should be
4287 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4288 is not NULL_TREE, it is evaluated before calculating the final
4289 array size, and if it fails, the array size is replaced with
4290 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4291 is non-NULL, it will be set, upon return, to the allocation
4292 function called. */
4294 tree
4299 {
4301 tree fns;
4308 /* Set to (size_t)-1 if the size check fails. */
4310 {
4316 }
4322 /* Based on:
4324 [expr.new]
4326 If this lookup fails to find the name, or if the allocated type
4327 is not a class type, the allocation function's name is looked
4328 up in the global scope.
4330 we disregard block-scope declarations of "operator new". */
4334 {
4339 /* If no aligned allocation function matches, try again without the
4340 alignment. */
4341 }
4343 /* Figure out what function is being called. */
4346 complain);
4348 /* If no suitable function could be found, issue an error message
4349 and give up. */
4351 {
4355 }
4357 /* If a cookie is required, add some extra space. Whether
4358 or not a cookie is required cannot be determined until
4359 after we know which function was called. */
4361 {
4363 tree arg_types;
4366 /* Skip the size_t parameter. */
4368 /* Check the remaining parameters (if any). */
4372 ptr_type_node))
4374 /* If we need a cookie, adjust the number of bytes allocated. */
4376 {
4377 /* Update the total size. */
4380 {
4381 /* Set to (size_t)-1 if the size check fails. */
4385 }
4386 /* Update the argument list to reflect the adjusted size. */
4388 }
4389 else
4391 }
4393 /* Tell our caller which function we decided to call. */
4397 /* Build the CALL_EXPR. */
4399 }
4401 /* Build a new call to operator(). This may change ARGS. */
4403 static tree
4405 {
4419 {
4421 /* It's no good looking for an overloaded operator() on a
4422 pointer-to-member-function. */
4423 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4425 }
4428 {
4432 }
4433 else
4437 {
4441 }
4443 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4447 {
4455 }
4460 {
4469 {
4476 add_template_conv_candidate
4480 else
4484 }
4485 }
4487 /* Be strict here because if we choose a bad conversion candidate, the
4488 errors we get won't mention the call context. */
4491 {
4493 {
4497 }
4499 }
4500 else
4501 {
4504 {
4506 {
4510 }
4512 }
4513 /* Since cand->fn will be a type, not a function, for a conversion
4514 function, we must be careful not to unconditionally look at
4515 DECL_NAME here. */
4519 else
4520 {
4524 else
4528 }
4529 }
4531 /* Free all the conversions we allocated. */
4535 }
4537 /* Wrapper for above. */
4539 tree
4541 {
4542 tree ret;
4547 }
4549 /* Called by op_error to prepare format strings suitable for the error
4550 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4551 and a suffix (controlled by NTYPES). */
4555 {
4565 else
4569 }
4571 static void
4574 {
4579 else
4583 {
4589 else
4601 else
4611 else
4622 else
4632 else
4637 else
4641 else
4646 }
4647 }
4649 /* Return the implicit conversion sequence that could be used to
4650 convert E1 to E2 in [expr.cond]. */
4654 {
4660 /* [expr.cond]
4662 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4663 implicitly converted (clause _conv_) to the type "lvalue reference to
4664 T2", subject to the constraint that in the conversion the
4665 reference must bind directly (_dcl.init.ref_) to an lvalue.
4667 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4668 implicitly converted to the type "rvalue reference to T2", subject to
4669 the constraint that the reference must bind directly. */
4671 {
4674 t1,
4675 e1,
4677 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4679 complain);
4682 }
4684 /* If E2 is a prvalue or if neither of the conversions above can be done
4685 and at least one of the operands has (possibly cv-qualified) class
4686 type: */
4690 /* [expr.cond]
4692 If E1 and E2 have class type, and the underlying class types are
4693 the same or one is a base class of the other: E1 can be converted
4694 to match E2 if the class of T2 is the same type as, or a base
4695 class of, the class of T1, and the cv-qualification of T2 is the
4696 same cv-qualification as, or a greater cv-qualification than, the
4697 cv-qualification of T1. If the conversion is applied, E1 is
4698 changed to an rvalue of type T2 that still refers to the original
4699 source class object (or the appropriate subobject thereof). */
4702 {
4704 {
4709 else
4712 }
4713 else
4715 }
4716 else
4717 /* [expr.cond]
4719 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4720 converted to the type that expression E2 would have if E2 were
4721 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4724 }
4726 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4727 arguments to the conditional expression. */
4729 static tree
4731 tsubst_flags_t complain)
4732 {
4733 tree arg2_type;
4734 tree arg3_type;
4743 /* As a G++ extension, the second argument to the conditional can be
4744 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4745 c'.) If the second operand is omitted, make sure it is
4746 calculated only once. */
4748 {
4756 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4759 else
4761 }
4763 /* If something has already gone wrong, just pass that fact up the
4764 tree. */
4774 {
4777 /* If arg1 is another cond_expr choosing between -1 and 0,
4778 then we can use its comparison. It may help to avoid
4779 additional comparison, produce more accurate diagnostics
4780 and enables folding. */
4790 /* force_rvalue can return error_mark on valid arguments. */
4801 {
4802 /* Rely on the error messages of the scalar version. */
4811 {
4819 }
4823 /* We could pass complain & tf_warning to unsafe_conversion_p,
4824 but the warnings (like Wsign-conversion) have already been
4825 given by the scalar build_conditional_expr_1. We still check
4826 unsafe_conversion_p to forbid truncating long long -> float. */
4828 {
4833 }
4835 {
4840 }
4850 }
4853 {
4859 {
4863 {
4869 }
4871 {
4877 }
4880 }
4881 }
4887 {
4890 "incompatible vector types in conditional expression: "
4894 }
4897 {
4900 }
4902 }
4904 /* [expr.cond]
4906 The first expression is implicitly converted to bool (clause
4907 _conv_). */
4909 LOOKUP_NORMAL);
4913 /* [expr.cond]
4915 If either the second or the third operand has type (possibly
4916 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4917 array-to-pointer (_conv.array_), and function-to-pointer
4918 (_conv.func_) standard conversions are performed on the second
4919 and third operands. */
4923 {
4924 /* Do the conversions. We don't these for `void' type arguments
4925 since it can't have any effect and since decay_conversion
4926 does not handle that case gracefully. */
4934 /* [expr.cond]
4936 One of the following shall hold:
4938 --The second or the third operand (but not both) is a
4939 throw-expression (_except.throw_); the result is of the
4940 type of the other and is an rvalue.
4942 --Both the second and the third operands have type void; the
4943 result is of type void and is an rvalue.
4945 We must avoid calling force_rvalue for expressions of type
4946 "void" because it will complain that their value is being
4947 used. */
4950 {
4952 {
4956 }
4959 }
4962 {
4964 {
4968 }
4971 }
4974 else
4975 {
4977 {
4980 "second operand to the conditional operator "
4981 "is of type %<void%>, but the third operand is "
4983 else
4985 "third operand to the conditional operator "
4986 "is of type %<void%>, but the second operand is "
4988 }
4990 }
4994 }
4995 /* [expr.cond]
4997 Otherwise, if the second and third operand have different types,
4998 and either has (possibly cv-qualified) class type, or if both are
4999 glvalues of the same value category and the same type except for
5000 cv-qualification, an attempt is made to convert each of those operands
5001 to the type of the other. */
5005 arg3_type)
5008 {
5013 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5019 /* [expr.cond]
5021 If both can be converted, or one can be converted but the
5022 conversion is ambiguous, the program is ill-formed. If
5023 neither can be converted, the operands are left unchanged and
5024 further checking is performed as described below. If exactly
5025 one conversion is possible, that conversion is applied to the
5026 chosen operand and the converted operand is used in place of
5027 the original operand for the remainder of this section. */
5032 {
5034 {
5041 else
5043 }
5045 }
5047 {
5051 /* Even if CONV2 is a valid conversion, the result of the
5052 conversion may be invalid. For example, if ARG3 has type
5053 "volatile X", and X does not have a copy constructor
5054 accepting a "volatile X&", then even if ARG2 can be
5055 converted to X, the conversion will fail. */
5059 }
5061 {
5068 }
5070 /* Free all the conversions we allocated. */
5076 /* If, after the conversion, both operands have class type,
5077 treat the cv-qualification of both operands as if it were the
5078 union of the cv-qualification of the operands.
5080 The standard is not clear about what to do in this
5081 circumstance. For example, if the first operand has type
5082 "const X" and the second operand has a user-defined
5083 conversion to "volatile X", what is the type of the second
5084 operand after this step? Making it be "const X" (matching
5085 the first operand) seems wrong, as that discards the
5086 qualification without actually performing a copy. Leaving it
5087 as "volatile X" seems wrong as that will result in the
5088 conditional expression failing altogether, even though,
5089 according to this step, the one operand could be converted to
5090 the type of the other. */
5098 }
5100 /* [expr.cond]
5102 If the second and third operands are glvalues of the same value
5103 category and have the same type, the result is of that type and
5104 value category. */
5108 {
5113 }
5115 /* [expr.cond]
5117 Otherwise, the result is an rvalue. If the second and third
5118 operand do not have the same type, and either has (possibly
5119 cv-qualified) class type, overload resolution is used to
5120 determine the conversions (if any) to be applied to the operands
5121 (_over.match.oper_, _over.built_). */
5125 {
5130 /* Rearrange the arguments so that add_builtin_candidate only has
5131 to know about two args. In build_builtin_candidate, the
5132 arguments are unscrambled. */
5137 COND_EXPR,
5138 NOP_EXPR,
5140 args,
5143 /* [expr.cond]
5145 If the overload resolution fails, the program is
5146 ill-formed. */
5149 {
5154 }
5157 {
5159 {
5162 }
5164 }
5166 /* [expr.cond]
5168 Otherwise, the conversions thus determined are applied, and
5169 the converted operands are used in place of the original
5170 operands for the remainder of this section. */
5179 }
5181 /* [expr.cond]
5183 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5184 and function-to-pointer (_conv.func_) standard conversions are
5185 performed on the second and third operands.
5187 We need to force the lvalue-to-rvalue conversion here for class types,
5188 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5189 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5190 regions. */
5203 /* [expr.cond]
5205 After those conversions, one of the following shall hold:
5207 --The second and third operands have the same type; the result is of
5208 that type. */
5211 /* [expr.cond]
5213 --The second and third operands have arithmetic or enumeration
5214 type; the usual arithmetic conversions are performed to bring
5215 them to a common type, and the result is of that type. */
5220 {
5221 /* In this case, there is always a common type. */
5223 arg3_type);
5226 "implicit conversion from %qT to %qT to "
5228 loc);
5232 {
5236 /* Two enumerators from the same enumeration can have different
5242 }
5249 {
5253 }
5257 }
5258 /* [expr.cond]
5260 --The second and third operands have pointer type, or one has
5261 pointer type and the other is a null pointer constant; pointer
5262 conversions (_conv.ptr_) and qualification conversions
5263 (_conv.qual_) are performed to bring them to their composite
5264 pointer type (_expr.rel_). The result is of the composite
5265 pointer type.
5267 --The second and third operands have pointer to member type, or
5268 one has pointer to member type and the other is a null pointer
5269 constant; pointer to member conversions (_conv.mem_) and
5270 qualification conversions (_conv.qual_) are performed to bring
5271 them to a common type, whose cv-qualification shall match the
5272 cv-qualification of either the second or the third operand.
5273 The result is of the common type. */
5281 {
5284 complain);
5289 }
5292 {
5297 }
5302 valid_operands:
5305 /* We can't use result_type below, as fold might have returned a
5306 throw_expr. */
5309 {
5310 /* Expand both sides into the same slot, hopefully the target of
5311 the ?: expression. We used to check for TARGET_EXPRs here,
5312 but now we sometimes wrap them in NOP_EXPRs so the test would
5313 fail. */
5316 /* If this expression is an rvalue, but might be mistaken for an
5317 lvalue, we must add a NON_LVALUE_EXPR. */
5319 }
5320 else
5324 }
5326 /* Wrapper for above. */
5328 tree
5330 tsubst_flags_t complain)
5331 {
5332 tree ret;
5337 }
5339 /* OPERAND is an operand to an expression. Perform necessary steps
5340 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5341 returned. */
5343 static tree
5345 {
5347 {
5350 /* Make sure the template type is instantiated now. */
5352 }
5355 }
5357 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5358 OVERLOAD) to the CANDIDATES, returning an updated list of
5359 CANDIDATES. The ARGS are the arguments provided to the call;
5360 if FIRST_ARG is non-null it is the implicit object argument,
5361 otherwise the first element of ARGS is used if needed. The
5362 EXPLICIT_TARGS are explicit template arguments provided.
5363 TEMPLATE_ONLY is true if only template functions should be
5364 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5365 add_function_candidate. */
5367 static void
5369 tree return_type,
5374 tsubst_flags_t complain)
5375 {
5376 tree ctype;
5380 unification_kind_t strict;
5381 tree fn;
5386 /* Precalculate special handling of constructors and conversion ops. */
5389 {
5393 /* We're doing return_type(x). */
5395 else
5396 /* We're doing x.operator return_type(). */
5398 /* [over.match.funcs] For conversion functions, the function
5399 is considered to be a member of the class of the implicit
5400 object argument for the purpose of defining the type of
5401 the implicit object parameter. */
5403 }
5404 else
5405 {
5407 {
5409 /* For list-initialization we consider explicit constructors
5410 and complain if one is chosen. */
5411 check_converting
5414 }
5415 else
5416 {
5419 }
5422 }
5426 else
5427 /* Delay creating the implicit this parameter until it is needed. */
5431 {
5432 tree fn_first_arg;
5442 /* Figure out which set of arguments to use. */
5444 {
5445 /* If this function is a non-static member and we didn't get an
5446 implicit object argument, move it out of args. */
5448 {
5450 tree arg;
5457 }
5461 }
5462 else
5463 {
5464 /* Otherwise, just use the list of arguments provided. */
5467 }
5471 fn,
5472 ctype,
5473 explicit_targs,
5474 fn_first_arg,
5475 fn_args,
5476 return_type,
5477 access_path,
5478 conversion_path,
5479 flags,
5480 strict,
5481 complain);
5484 fn,
5485 ctype,
5486 fn_first_arg,
5487 fn_args,
5488 access_path,
5489 conversion_path,
5490 flags,
5491 complain);
5492 }
5493 }
5495 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5496 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5498 static int
5500 {
5502 {
5503 // 5. b @= a
5507 // 6. a[b]
5511 // 1. a.b
5512 // Not overloadable (yet).
5513 // 2. a->b
5514 // Only one argument.
5515 // 3. a->*b
5517 // 7. a << b
5519 // 8. a >> b
5525 }
5526 }
5528 static tree
5531 {
5534 tree fnname;
5552 {
5556 }
5557 else
5564 {
5569 /* Use build_op_new_call and build_op_delete_call instead. */
5573 /* Use build_op_call instead. */
5580 /* These are saved for the sake of warn_logical_operator. */
5590 /* These are saved for the sake of maybe_warn_bool_compare. */
5595 /* =, ->, [], () must be non-static member functions. */
5599 /* FALLTHRU */
5607 }
5613 /* Use build_conditional_expr instead. */
5629 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5632 /* Add namespace-scope operators to the list of functions to
5633 consider. */
5645 /* Add class-member operators to the candidate set. */
5647 {
5648 tree fns;
5652 {
5655 }
5663 }
5664 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5665 only non-member functions that have type T1 or reference to
5666 cv-qualified-opt T1 for the first argument, if the first argument
5667 has an enumeration type, or T2 or reference to cv-qualified-opt
5668 T2 for the second argument, if the second argument has an
5669 enumeration type. Filter out those that don't match. */
5671 {
5675 {
5685 {
5691 && (same_type_ignoring_top_level_qualifiers_p
5696 }
5698 /* No argument has an appropriate type, so remove this
5699 candidate function from the list. */
5701 {
5704 }
5705 }
5706 }
5712 {
5715 /* For these, the built-in candidates set is empty
5716 [over.match.oper]/3. We don't want non-strict matches
5717 because exact matches are always possible with built-in
5718 operators. The built-in candidate set for COMPONENT_REF
5719 would be empty too, but since there are no such built-in
5720 operators, we accept non-strict matches for them. */
5727 }
5731 {
5733 {
5736 /* Don't try anything fancy if we're not allowed to produce
5737 errors. */
5741 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5742 distinguish between prefix and postfix ++ and
5743 operator++() was used for both, so we allow this with
5744 -fpermissive. */
5745 else
5746 {
5752 }
5759 else
5765 /* The caller will deal with these. */
5775 {
5776 /* If one of the arguments of the operator represents
5777 an invalid use of member function pointer, try to report
5778 a meaningful error ... */
5783 else
5784 {
5785 /* ... Otherwise, report the more generic
5786 "no matching operator found" error */
5789 }
5790 }
5793 }
5794 }
5795 else
5796 {
5799 {
5801 {
5804 }
5806 }
5808 {
5814 else
5820 {
5825 /* This prevents build_new_function_call from discarding this
5826 function during instantiation of the enclosing template. */
5829 /* Specify evaluation order as per P0145R2. */
5832 {
5843 }
5844 }
5845 }
5846 else
5847 {
5848 /* Give any warnings we noticed during overload resolution. */
5850 {
5854 }
5856 /* Check for comparison of different enum types. */
5858 {
5870 {
5874 }
5878 }
5880 /* We need to strip any leading REF_BIND so that bitfields
5881 don't cause errors. This should not remove any important
5882 conversions, because builtins don't apply to class
5883 objects directly. */
5890 {
5894 else
5897 /* We need to call warn_logical_operator before
5898 converting arg2 to a boolean_type, but after
5899 decaying an enumerator to its value. */
5906 }
5908 {
5913 }
5915 }
5916 }
5918 user_defined_result_ready:
5920 /* Free all the conversions we allocated. */
5926 builtin:
5928 {
5943 /* Fall through. */
5956 /* Fall through. */
5989 complain),
5992 /* The caller will deal with these. */
6000 }
6002 }
6004 /* Wrapper for above. */
6006 tree
6010 {
6011 tree ret;
6017 }
6019 /* CALL was returned by some call-building function; extract the actual
6020 CALL_EXPR from any bits that have been tacked on, e.g. by
6021 convert_from_reference. */
6023 tree
6025 {
6036 }
6038 /* Returns true if FN has two parameters, of which the second has type
6039 size_t. */
6041 static bool
6043 {
6055 }
6057 /* True if T, an allocation function, has std::align_val_t as its second
6058 argument. */
6060 bool
6062 {
6068 }
6070 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6071 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6072 std::align_val_t. */
6074 static bool
6076 {
6080 /* A template instance is never a usual deallocation function,
6081 regardless of its signature. */
6097 }
6099 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6100 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6102 bool
6104 {
6105 /* A template instance is never a usual deallocation function,
6106 regardless of its signature. */
6111 /* If a class T has a member deallocation function named operator delete
6112 with exactly one parameter, then that function is a usual
6113 (non-placement) deallocation function. If class T does not declare
6114 such an operator delete but does declare a member deallocation
6115 function named operator delete with exactly two parameters, the second
6116 of which has type std::size_t (18.2), then this function is a usual
6117 deallocation function. */
6129 }
6131 /* Build a call to operator delete. This has to be handled very specially,
6132 because the restrictions on what signatures match are different from all
6133 other call instances. For a normal delete, only a delete taking (void *)
6134 or (void *, size_t) is accepted. For a placement delete, only an exact
6135 match with the placement new is accepted.
6137 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6138 ADDR is the pointer to be deleted.
6139 SIZE is the size of the memory block to be deleted.
6140 GLOBAL_P is true if the delete-expression should not consider
6141 class-specific delete operators.
6142 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6144 If this call to "operator delete" is being generated as part to
6145 deallocate memory allocated via a new-expression (as per [expr.new]
6146 which requires that if the initialization throws an exception then
6147 we call a deallocation function), then ALLOC_FN is the allocation
6148 function. */
6150 tree
6154 {
6168 /* In [class.free]
6170 If the result of the lookup is ambiguous or inaccessible, or if
6171 the lookup selects a placement deallocation function, the
6172 program is ill-formed.
6174 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6175 {
6179 }
6180 else
6186 /* Strip const and volatile from addr. */
6190 {
6191 /* "A declaration of a placement deallocation function matches the
6192 declaration of a placement allocation function if it has the same
6193 number of parameters and, after parameter transformations (8.3.5),
6194 all parameter types except the first are identical."
6196 So we build up the function type we want and ask instantiate_type
6197 to get it for us. */
6209 /* "If the lookup finds the two-parameter form of a usual deallocation
6210 function (3.7.4.2) and that function, considered as a placement
6211 deallocation function, would have been selected as a match for the
6212 allocation function, the program is ill-formed." */
6214 {
6222 /* But if the class has an operator delete (void *), then that is
6223 the usual deallocation function, so we shouldn't complain
6224 about using the operator delete (void *, size_t). */
6228 {
6233 }
6234 /* Before C++14 a two-parameter global deallocation function is
6235 always a placement deallocation function, but warn if
6236 -Wc++14-compat. */
6238 {
6243 }
6246 {
6248 {
6249 /* Only mention C++14 for namespace-scope delete. */
6252 else
6254 "%qD is a usual (non-placement) deallocation "
6256 }
6257 }
6258 else
6260 ok:;
6261 }
6262 }
6263 else
6264 /* "Any non-placement deallocation function matches a non-placement
6265 allocation function. If the lookup finds a single matching
6266 deallocation function, that function will be called; otherwise, no
6267 deallocation function will be called." */
6270 {
6273 {
6275 {
6278 }
6280 /* -- If the type has new-extended alignment, a function with a
6281 parameter of type std::align_val_t is preferred; otherwise a
6282 function without such a parameter is preferred. If exactly one
6283 preferred function is found, that function is selected and the
6284 selection process terminates. If more than one preferred
6285 function is found, all non-preferred functions are eliminated
6286 from further consideration. */
6288 {
6294 {
6298 }
6299 }
6301 /* -- If the deallocation functions have class scope, the one
6302 without a parameter of type std::size_t is selected. */
6307 /* -- If the type is complete and if, for the second alternative
6308 (delete array) only, the operand is a pointer to a class type
6309 with a non-trivial destructor or a (possibly multi-dimensional)
6310 array thereof, the function with a parameter of type std::size_t
6311 is selected.
6313 -- Otherwise, it is unspecified whether a deallocation function
6314 with a parameter of type std::size_t is selected. */
6315 else
6316 {
6320 /* We need a cookie to determine the array size. */
6322 }
6328 }
6329 }
6331 /* If we have a matching function, call it. */
6333 {
6336 /* If the FN is a member function, make sure that it is
6337 accessible. */
6340 complain);
6342 /* Core issue 901: It's ok to new a type with deleted delete. */
6347 {
6348 /* The placement args might not be suitable for overload
6349 resolution at this point, so build the call directly. */
6359 }
6360 else
6361 {
6362 tree ret;
6368 {
6371 }
6375 }
6376 }
6378 /* [expr.new]
6380 If no unambiguous matching deallocation function can be found,
6381 propagating the exception does not cause the object's memory to
6382 be freed. */
6384 {
6388 alloc_fn);
6390 }
6396 }
6398 /* If the current scope isn't allowed to access DECL along
6399 BASETYPE_PATH, give an error. The most derived class in
6400 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6401 the declaration to use in the error diagnostic. */
6403 bool
6405 tsubst_flags_t complain)
6406 {
6411 {
6412 /* 7.3.3/18: The additional constructors are accessible if they would be
6413 accessible when used to construct an object of the corresponding base
6414 class. */
6417 }
6420 {
6422 {
6426 {
6430 }
6432 {
6436 }
6437 else
6438 {
6441 }
6442 }
6444 }
6447 }
6449 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6450 bitwise or of LOOKUP_* values. If any errors are warnings are
6451 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6452 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6453 to NULL. */
6455 static tree
6458 {
6464 /* If the source is a packed field, calling the copy constructor will require
6465 binding the field to the reference parameter to the copy constructor, and
6466 we'll end up with an infinite loop. If we can use a bitwise copy, then
6467 do that now. */
6483 }
6485 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6486 EXPR is implicitly converted to type TOTYPE.
6487 FN and ARGNUM are used for diagnostics. */
6489 static void
6491 {
6492 /* Issue warnings about peculiar, but valid, uses of NULL. */
6495 {
6496 source_location loc =
6503 else
6506 }
6508 /* Issue warnings if "false" is converted to a NULL pointer */
6511 {
6514 "converting %<false%> to pointer type for argument %P "
6516 else
6519 }
6520 }
6522 /* We gave a diagnostic during a conversion. If this was in the second
6523 standard conversion sequence of a user-defined conversion sequence, say
6524 which user-defined conversion. */
6526 static void
6528 {
6532 {
6536 }
6537 }
6539 /* Perform the conversions in CONVS on the expression EXPR. FN and
6540 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6541 indicates the `this' argument of a method. INNER is nonzero when
6542 being called to continue a conversion chain. It is negative when a
6543 reference binding will be applied, positive otherwise. If
6544 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6545 conversions will be emitted if appropriate. If C_CAST_P is true,
6546 this conversion is coming from a C-style cast; in that case,
6547 conversions to inaccessible bases are permitted. */
6549 static tree
6553 {
6555 diagnostic_t diag_kind;
6571 {
6575 /* Give a helpful error if this is bad because of excess braces. */
6580 {
6586 }
6588 /* Give a helpful error if this is bad because a conversion to bool
6589 from std::nullptr_t requires direct-initialization. */
6597 {
6599 {
6602 totype);
6608 complain);
6612 complain);
6613 else
6619 }
6621 {
6625 complain);
6627 }
6632 complain);
6635 }
6644 }
6650 {
6652 {
6656 /* When converting from an init list we consider explicit
6657 constructors, but actually trying to call one is an error. */
6660 /* Unless this is for direct-list-initialization. */
6662 /* And in C++98 a default constructor can't be explicit. */
6664 {
6670 {
6676 }
6677 else
6680 }
6682 /* If we're initializing from {}, it's value-initialization. */
6686 {
6691 {
6694 }
6696 }
6700 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6701 any more UDCs. */
6703 complain);
6705 /* If this is a constructor or a function returning an aggr type,
6706 we need to build up a TARGET_EXPR. */
6708 {
6711 /* Remember that this was list-initialization. */
6714 }
6717 }
6720 {
6726 else
6728 }
6733 /* Convert a constant to its underlying value, unless we are
6734 about to bind it to a reference, in which case we need to
6735 leave it as an lvalue. */
6737 {
6740 /* If __null has been converted to an integer type, we do not
6741 want to warn about uses of EXPR as an integer, rather than
6742 as a pointer. */
6744 }
6747 /* We leave bad_p off ck_ambig because overload resolution considers
6748 it valid, it just fails when we try to perform it. So we need to
6749 check complain here, too. */
6751 {
6752 /* Call build_user_type_conversion again for the error. */
6754 complain);
6758 }
6762 {
6763 /* Conversion to std::initializer_list<T>. */
6771 /* Convert all the elements. */
6773 {
6784 }
6785 /* Build up the array. */
6786 elttype = cp_build_qualified_type
6790 /* Take the address explicitly rather than via decay_conversion
6791 to avoid the error about taking the address of a temporary. */
6797 /* Build up the initializer_list object. */
6805 }
6809 {
6818 }
6821 complain);
6828 };
6833 c_cast_p,
6834 complain);
6839 {
6843 {
6845 {
6850 }
6852 }
6857 /* Don't introduce copies when passing arguments along to the inherited
6858 constructor. */
6860 && flag_new_inheriting_ctors
6864 /* Fall through. */
6867 {
6868 /* We are going to bind a reference directly to a base-class
6869 subobject of EXPR. */
6870 /* Build an expression for `*((base*) &expr)'. */
6874 }
6876 /* Copy-initialization where the cv-unqualified version of the source
6877 type is the same class as, or a derived class of, the class of the
6878 destination [is treated as direct-initialization]. [dcl.init] */
6881 /* This conversion is being done in the context of a user-defined
6882 conversion (i.e. the second step of copy-initialization), so
6883 don't allow any more. */
6885 else
6891 /* Copy-list-initialization doesn't actually involve a copy. */
6895 {
6900 }
6905 {
6909 {
6922 else
6929 }
6931 /* If necessary, create a temporary.
6933 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6934 that need temporaries, even when their types are reference
6935 compatible with the type of reference being bound, so the
6936 upcoming call to cp_build_addr_expr doesn't fail. */
6940 {
6941 /* Otherwise, a temporary of type "cv1 T1" is created and
6942 initialized from the initializer expression using the rules
6943 for a non-reference copy-initialization (8.5). */
6952 {
6953 /* If the reference is volatile or non-const, we
6954 cannot create a temporary. */
6961 else
6965 }
6966 /* If the source is a packed field, and we must use a copy
6967 constructor, then building the target expr will require
6968 binding the field to the reference parameter to the
6969 copy constructor, and we'll end up with an infinite
6970 loop. If we can use a bitwise copy, then we'll be
6971 OK. */
6975 {
6979 }
6981 {
6984 }
6986 }
6988 /* Take the address of the thing to which we will bind the
6989 reference. */
6994 /* Convert it to a pointer to the type referred to by the
6995 reference. This will adjust the pointer if a derived to
6996 base conversion is being performed. */
6999 /* Convert the pointer to the desired reference type. */
7001 }
7007 /* ??? Should the address of a transaction-safe pointer point to the TM
7008 clone, and this conversion look up the primary function? */
7012 /* Warn about deprecated conversion if appropriate. */
7028 }
7036 else
7040 }
7042 /* ARG is being passed to a varargs function. Perform any conversions
7043 required. Return the converted value. */
7045 tree
7047 {
7048 tree arg_type;
7051 /* [expr.call]
7053 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7054 standard conversions are performed. */
7057 /* [expr.call]
7059 If the argument has integral or enumeration type that is subject
7060 to the integral promotions (_conv.prom_), or a floating point
7061 type that is subject to the floating point promotion
7062 (_conv.fpprom_), the value of the argument is converted to the
7063 promoted type before the call. */
7068 {
7072 "implicit conversion from %qT to %qT when passing "
7076 }
7080 {
7082 {
7084 complain);
7094 }
7095 else
7097 }
7103 /* In a template (or ill-formed code), we can have an incomplete type
7104 even after require_complete_type_sfinae, in which case we don't know
7105 whether it has trivial copy or not. */
7107 {
7108 /* Build up a real lvalue-to-rvalue conversion in case the
7109 copy constructor is trivial but not callable. */
7113 /* [expr.call] 5.2.2/7:
7114 Passing a potentially-evaluated argument of class type (Clause 9)
7115 with a non-trivial copy constructor or a non-trivial destructor
7116 with no corresponding parameter is conditionally-supported, with
7117 implementation-defined semantics.
7119 We support it as pass-by-invisible-reference, just like a normal
7120 value parameter.
7122 If the call appears in the context of a sizeof expression,
7123 it is not potentially-evaluated. */
7127 {
7130 "passing objects of non-trivially-copyable "
7132 arg_type);
7134 }
7135 }
7138 }
7140 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7142 tree
7144 {
7146 {
7150 }
7160 {
7163 }
7167 {
7168 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7169 it as pass by invisible reference. */
7171 "receiving objects of non-trivially-copyable type %q#T "
7177 }
7181 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7182 know how to handle it. */
7185 }
7187 /* TYPE has been given to va_arg. Apply the default conversions which
7188 would have happened when passed via ellipsis. Return the promoted
7189 type, or the passed type if there is no change. */
7191 tree
7193 {
7194 tree promote;
7196 /* Perform the array-to-pointer and function-to-pointer
7197 conversions. */
7205 }
7207 /* ARG is a default argument expression being passed to a parameter of
7208 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7209 zero-based argument number. Do any required conversions. Return
7210 the converted value. */
7213 void
7217 void
7221 tree
7223 tsubst_flags_t complain)
7224 {
7226 tree t;
7228 /* See through clones. */
7230 /* And inheriting ctors. */
7234 /* Detect recursion. */
7237 {
7241 }
7243 /* If the ARG is an unparsed default argument expression, the
7244 conversion cannot be performed. */
7246 {
7251 }
7258 /* Due to:
7260 [dcl.fct.default]
7262 The names in the expression are bound, and the semantic
7263 constraints are checked, at the point where the default
7264 expressions appears.
7266 we must not perform access checks here. */
7268 /* We must make a copy of ARG, in case subsequent processing
7269 alters any part of it. */
7273 complain);
7280 }
7282 /* Returns the type which will really be used for passing an argument of
7283 type TYPE. */
7285 tree
7287 {
7288 /* Pass classes with copy ctors by invisible reference. */
7290 {
7292 /* There are no other pointers to this temporary. */
7294 }
7302 }
7304 /* Actually perform the appropriate conversion. */
7306 tree
7308 {
7309 tree bitfield_type;
7311 /* If VAL is a bitfield, then -- since it has already been converted
7312 to TYPE -- it cannot have a precision greater than TYPE.
7314 If it has a smaller precision, we must widen it here. For
7315 example, passing "int f:3;" to a function expecting an "int" will
7316 not result in any conversion before this point.
7318 If the precision is the same we must not risk widening. For
7319 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7320 often have type "int", even though the C++ type for the field is
7321 "long long". If the value is being passed to a function
7322 expecting an "int", then no conversions will be required. But,
7323 if we call convert_bitfield_to_declared_type, the bitfield will
7324 be converted to "long long". */
7331 ;
7332 /* Pass classes with copy ctors by invisible reference. */
7342 {
7351 }
7353 }
7355 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7356 which just decay_conversion or no conversions at all should be done.
7357 This is true for some builtins which don't act like normal functions.
7358 Return 2 if no conversions at all should be done, 1 if just
7359 decay_conversion. Return 3 for special treatment of the 3rd argument
7360 for __builtin_*_overflow_p. */
7362 int
7364 {
7370 {
7385 }
7388 }
7390 /* Returns the decl of the dispatcher function if FN is a function version. */
7392 tree
7394 {
7404 {
7408 }
7413 }
7415 /* fn is a function version dispatcher that is marked used. Mark all the
7416 semantically identical function versions it will dispatch as used. */
7418 void
7420 {
7437 /* All semantically identical versions are chained. Traverse and mark each
7438 one of them as used. */
7441 {
7444 }
7445 }
7447 /* Build a call to "the copy constructor" for the type of A, even if it
7448 wouldn't be selected by normal overload resolution. Used for
7449 diagnostics. */
7451 static tree
7453 {
7464 }
7466 /* Return true iff T refers to a base field. */
7468 static bool
7470 {
7479 }
7481 /* We can't elide a copy from a function returning by value to a base
7482 subobject, as the callee might clobber tail padding. Return true iff this
7483 could be that case. */
7485 static bool
7487 {
7488 /* Copy elision only happens with a TARGET_EXPR. */
7492 /* It's safe to elide the copy for a class with no tail padding. */
7495 /* It's safe to elide the copy if we aren't initializing a base object. */
7499 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7504 }
7506 /* Subroutine of the various build_*_call functions. Overload resolution
7507 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7508 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7509 bitmask of various LOOKUP_* flags which apply to the call itself. */
7511 static tree
7513 {
7521 tree val;
7530 /* In a template, there is no need to perform all of the work that
7531 is normally done. We are only interested in the type of the call
7532 expression, i.e., the return type of the function. Any semantic
7533 errors will be deferred until the template is instantiated. */
7535 {
7537 tree return_type;
7545 else
7546 {
7549 tree arg;
7557 }
7567 }
7569 /* Give any warnings we noticed during overload resolution. */
7571 {
7575 }
7577 /* Make =delete work with SFINAE. */
7582 {
7583 tree access_fn;
7584 /* If FN is a template function, two cases must be considered.
7585 For example:
7587 struct A {
7588 protected:
7589 template <class T> void f();
7590 };
7591 template <class T> struct B {
7592 protected:
7593 void g();
7594 };
7595 struct C : A, B<int> {
7596 using A::f; // #1
7597 using B<int>::g; // #2
7598 };
7600 In case #1 where `A::f' is a member template, DECL_ACCESS is
7601 recorded in the primary template but not in its specialization.
7602 We check access of FN using its primary template.
7604 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7605 because it is a member of class template B, DECL_ACCESS is
7606 recorded in the specialization `B<int>::g'. We cannot use its
7607 primary template because `B<T>::g' and `B<int>::g' may have
7608 different access. */
7612 else
7617 }
7619 /* If we're checking for implicit delete, don't bother with argument
7620 conversions. */
7622 {
7624 {
7628 }
7632 /* Reject bad conversions now. */
7634 /* else continue to get conversion error. */
7635 }
7637 /* N3276 magic doesn't apply to nested calls. */
7641 /* Find maximum size of vector to hold converted arguments. */
7648 /* The implicit parameters to a constructor are not considered by overload
7649 resolution, and must be of the proper type. */
7651 {
7652 tree object_arg;
7654 {
7657 }
7658 else
7659 {
7662 }
7665 /* We should never try to call the abstract constructor. */
7669 {
7673 }
7674 }
7675 /* Bypass access control for 'this' parameter. */
7677 {
7680 ? first_arg
7683 tree converted_arg;
7684 tree base_binfo;
7687 {
7689 {
7694 }
7695 else
7697 }
7699 /* See if the function member or the whole class type is declared
7700 final and the call can be devirtualized. */
7705 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7706 X is called for an object that is not of type X, or of a type
7707 derived from X, the behavior is undefined.
7709 So we can assume that anything passed as 'this' is non-null, and
7710 optimize accordingly. */
7712 /* Convert to the base in which the function was declared. */
7715 arg,
7718 /* Check that the base class is accessible. */
7721 {
7726 else
7728 }
7729 /* If fn was found by a using declaration, the conversion path
7730 will be to the derived class, not the base declaring fn. We
7731 must convert from derived to base. */
7742 else
7746 }
7751 {
7758 /* If the argument is NULL and used to (implicitly) instantiate a
7759 template function (and bind one of the template arguments to
7760 the type of 'long int'), we don't want to warn about passing NULL
7761 to non-pointer argument.
7762 For example, if we have this template function:
7764 template<typename T> void func(T x) {}
7766 we want to warn (when -Wconversion is enabled) in this case:
7768 void foo() {
7769 func<int>(NULL);
7770 }
7772 but not in this case:
7774 void foo() {
7775 func(NULL);
7776 }
7777 */
7784 /* Warn about initializer_list deduction that isn't currently in the
7785 working draft. */
7787 && flag_deduce_init_list
7791 {
7804 {
7812 }
7813 }
7815 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7816 knows not to allow any more UDCs. This needs to happen after we
7817 process cand->warnings. */
7822 conversion_warning
7823 ? complain
7830 else
7832 }
7834 /* Default arguments */
7836 {
7842 complain);
7843 }
7845 /* Ellipsis */
7848 {
7851 {
7852 /* Do no conversions for certain magic varargs. */
7856 }
7858 /* For other magic varargs only do decay_conversion. */
7863 {
7864 /* Avoid infinite recursion trying to call A(...). */
7866 /* Try to call the actual copy constructor for a good error. */
7869 }
7870 else
7875 }
7880 /* Avoid to do argument-transformation, if warnings for format, and for
7881 nonnull are disabled. Just in case that at least one of them is active
7882 the check_function_arguments function might warn about something. */
7885 {
7892 }
7895 {
7896 /* Check for passing ellipsis arguments to an inherited constructor. We
7897 could handle this by open-coding the inherited constructor rather than
7898 defining it, but let's not bother now. */
7901 {
7903 {
7907 }
7909 }
7911 /* A base constructor inheriting from a virtual base doesn't get the
7912 inherited arguments, just this and __vtt. */
7915 }
7917 /* Avoid actually calling copy constructors and copy assignment operators,
7918 if possible. */
7925 /* It's unsafe to elide the constructor when handling
7926 a noexcept-expression, it may evaluate to the wrong
7927 value (c++/53025). */
7929 {
7930 tree targ;
7932 tree fa;
7935 /* Pull out the real argument, disregarding const-correctness. */
7941 {
7946 }
7947 else
7952 else
7955 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
7956 subobject. */
7960 /* See unsafe_copy_elision_p. */
7963 /* [class.copy]: the copy constructor is implicitly defined even if
7964 the implementation elided its use. */
7966 {
7970 }
7972 /* If we're creating a temp and we already have one, don't create a
7973 new one. If we're not creating a temp but we get one, use
7974 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7975 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7976 temp or an INIT_EXPR otherwise. */
7979 {
7984 }
7987 {
7989 RO_NULL,
7990 complain));
7994 }
7995 }
7999 {
8000 tree to = cp_stabilize_reference
8007 {
8008 /* Avoid copying empty classes. */
8011 }
8013 {
8016 }
8017 else
8018 {
8019 /* We must only copy the non-tail padding parts. */
8027 build_index_type
8036 }
8039 }
8042 {
8046 {
8049 else
8051 }
8052 }
8054 /* For calls to a multi-versioned function, overload resolution
8055 returns the function with the highest target priority, that is,
8056 the version that will checked for dispatching first. If this
8057 version is inlinable, a direct call to this version can be made
8058 otherwise the call should go through the dispatcher. */
8063 {
8069 }
8076 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8077 virtual functions can't be constexpr. */
8079 {
8080 tree t;
8087 complain);
8093 }
8094 else
8095 {
8099 }
8105 {
8107 /* build_new_op_1 will clear this when appropriate. */
8109 }
8111 }
8113 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8114 This function performs no overload resolution, conversion, or other
8115 high-level operations. */
8117 tree
8119 tsubst_flags_t complain)
8120 {
8121 tree fndecl;
8123 /* Remember roughly where this call is. */
8130 /* Check that arguments to builtin functions match the expectations. */
8134 {
8137 /* We need to take care that values to BUILT_IN_NORMAL
8138 are reduced. */
8145 }
8147 /* If it is a built-in array notation function, then the return type of
8148 the function is the element type of the array passed in as array
8149 notation (i.e. the first parameter of the function). */
8151 {
8160 {
8162 {
8165 }
8166 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8167 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8168 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8169 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8170 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8171 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8172 The pre-defined return-type is the correct one. */
8176 }
8177 }
8182 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8183 function call is either the operand of a decltype-specifier or the
8184 right operand of a comma operator that is the operand of a
8185 decltype-specifier, a temporary object is not introduced for the
8186 prvalue. The type of the prvalue may be incomplete. */
8188 {
8195 }
8197 }
8199 /* Returns the value to use for the in-charge parameter when making a
8200 call to a function with the indicated NAME.
8202 FIXME:Can't we find a neater way to do this mapping? */
8204 tree
8206 {
8217 /* This function should only be called with one of the names listed
8218 above. */
8221 }
8223 /* We've built up a constructor call RET. Complain if it delegates to the
8224 constructor we're currently compiling. */
8226 static void
8228 {
8234 }
8236 /* Build a call to a constructor, destructor, or an assignment
8237 operator for INSTANCE, an expression with class type. NAME
8238 indicates the special member function to call; *ARGS are the
8239 arguments. ARGS may be NULL. This may change ARGS. BINFO
8240 indicates the base of INSTANCE that is to be passed as the `this'
8241 parameter to the member function called.
8243 FLAGS are the LOOKUP_* flags to use when processing the call.
8245 If NAME indicates a complete object constructor, INSTANCE may be
8246 NULL_TREE. In this case, the caller will call build_cplus_new to
8247 store the newly constructed object into a VAR_DECL. */
8249 tree
8252 {
8253 tree fns;
8254 /* The type of the subobject to be constructed or destroyed. */
8255 tree class_type;
8257 tree ret;
8266 {
8267 /* Resolve the name. */
8272 }
8278 /* Handle the special case where INSTANCE is NULL_TREE. */
8281 else
8282 {
8288 /* Convert to the base class, if necessary. */
8291 {
8293 /* For constructors and destructors, either the base is
8294 non-virtual, or it is virtual but we are doing the
8295 conversion from a constructor or destructor for the
8296 complete object. In either case, we can convert
8297 statically. */
8299 else
8300 /* However, for assignment operators, we must convert
8301 dynamically if the base is virtual. */
8304 }
8305 }
8309 /* In C++17, "If the initializer expression is a prvalue and the
8310 cv-unqualified version of the source type is the same class as the class
8311 of the destination, the initializer expression is used to initialize the
8312 destination object." Handle that here to avoid doing overload
8313 resolution. */
8317 {
8320 /* FIXME P0135 doesn't say how to handle direct initialization from a
8321 type with a suitable conversion operator. Let's handle it like
8322 copy-initialization, but allowing explict conversions. */
8328 && (same_type_ignoring_top_level_qualifiers_p
8330 {
8336 /* Avoid change of behavior on Wunused-var-2.C. */
8339 }
8340 }
8344 /* When making a call to a constructor or destructor for a subobject
8345 that uses virtual base classes, pass down a pointer to a VTT for
8346 the subobject. */
8350 {
8351 tree vtt;
8352 tree sub_vtt;
8354 /* If the current function is a complete object constructor
8355 or destructor, then we fetch the VTT directly.
8356 Otherwise, we look it up using the VTT we were given. */
8364 else
8368 {
8371 }
8374 }
8379 complain);
8390 }
8392 /* Return the NAME, as a C string. The NAME indicates a function that
8393 is a member of TYPE. *FREE_P is set to true if the caller must
8394 free the memory returned.
8396 Rather than go through all of this, we should simply set the names
8397 of constructors and destructors appropriately, and dispense with
8398 ctor_identifier, dtor_identifier, etc. */
8402 {
8405 /* Assume that we will not allocate memory. */
8407 /* Constructors and destructors are special. */
8409 {
8410 pretty_name
8412 /* For a destructor, add the '~'. */
8416 {
8418 /* Remember that we need to free the memory allocated. */
8420 }
8421 }
8423 {
8426 TFF_PLAIN_IDENTIFIER),
8427 NULL);
8428 /* Remember that we need to free the memory allocated. */
8430 }
8431 else
8435 }
8437 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8438 be set, upon return, to the function called. ARGS may be NULL.
8439 This may change ARGS. */
8441 static tree
8445 {
8450 tree optype;
8452 tree name;
8455 tree call;
8456 tree fn;
8459 tree orig_instance;
8460 tree orig_fns;
8466 /* We don't know what function we're going to call, yet. */
8475 {
8479 }
8484 /* Dismantle the baselink to collect all the information we need. */
8492 {
8496 }
8507 {
8512 }
8515 /* Under DR 147 A::A() is an invalid constructor call,
8516 not a functional cast. */
8518 {
8528 complain);
8530 }
8532 /* Figure out whether to skip the first argument for the error
8533 message we will display to users if an error occurs. We don't
8534 want to display any compiler-generated arguments. The "this"
8535 pointer hasn't been added yet. However, we must remove the VTT
8536 pointer if this is a call to a base-class constructor or
8537 destructor. */
8540 {
8541 /* Callers should explicitly indicate whether they want to construct
8542 the complete object or just the part without virtual bases. */
8544 /* Similarly for destructors. */
8546 /* Remove the VTT pointer, if present. */
8550 }
8552 /* Process the argument list. */
8554 {
8558 }
8560 /* Consider the object argument to be used even if we end up selecting a
8561 static member function. */
8564 /* It's OK to call destructors and constructors on cv-qualified objects.
8565 Therefore, convert the INSTANCE to the unqualified type, if
8566 necessary. */
8569 {
8571 {
8575 }
8576 }
8580 /* For the overload resolution we need to find the actual `this`
8581 that would be captured if the call turns out to be to a
8582 non-static member function. Do not actually capture it at this
8583 point. */
8585 /* Constructors don't use the enclosing 'this'. */
8587 else
8590 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8593 /* The number of arguments artificial parms in ARGS; we subtract one because
8594 there's no 'this' in ARGS. */
8597 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8598 initializer, not T({ }). */
8602 {
8609 /* If the initializer list has no elements and T is a class type with
8610 a default constructor, the object is value-initialized. Handle
8611 this here so we don't need to handle it wherever we use
8612 build_special_member_call. */
8615 /* For a user-provided default constructor, use the normal
8616 mechanisms so that protected access works. */
8621 /* If BASETYPE is an aggregate, we need to do aggregate
8622 initialization. */
8624 {
8627 }
8630 {
8636 }
8638 /* Otherwise go ahead with overload resolution. */
8643 }
8644 else
8645 {
8649 }
8654 {
8656 {
8663 else
8664 {
8668 {
8671 }
8679 }
8681 }
8683 }
8684 else
8685 {
8688 {
8691 tree arglist;
8694 {
8702 else
8708 }
8710 }
8711 else
8712 {
8720 {
8721 /* This is not an error, it is runtime undefined
8722 behavior. */
8731 fn);
8732 }
8737 {
8742 {
8743 /* We captured 'this' in the current lambda now that
8744 we know we really need it. */
8746 }
8748 /* We can't tell until instantiation time whether we can use
8750 else
8751 {
8754 fn);
8756 }
8757 }
8760 {
8761 /* Optimize away vtable lookup if we know that this
8762 function can't be overridden. We need to check if
8763 the context and the type where we found fn are the same,
8764 actually FN might be defined in a different class
8765 type because of a using-declaration. In this case, we
8766 do not want to perform a non-virtual call. */
8768 && same_type_ignoring_top_level_qualifiers_p
8774 /* Now we know what function is being called. */
8777 /* Build the actual CALL_EXPR. */
8779 /* In an expression of the form `a->f()' where `f' turns
8780 out to be a static member function, `a' is
8781 none-the-less evaluated. */
8790 /* An explicit call of the form "x->~X()" has type
8791 "void". However, on platforms where destructors
8792 return "this" (i.e., those where
8793 targetm.cxx.cdtor_returns_this is true), such calls
8794 will appear to have a return value of pointer type
8795 to the low-level call machinery. We do not want to
8796 change the low-level machinery, since we want to be
8797 able to optimize "delete f()" on such platforms as
8798 "operator delete(~X(f()))" (rather than generating
8799 "t = f(), ~X(t), operator delete (t)"). */
8801 }
8802 }
8803 }
8806 {
8812 {
8815 }
8818 call = (build_min_non_dep_call_vec
8822 orig_args));
8827 }
8829 /* Free all the conversions we allocated. */
8836 }
8838 /* Wrapper for above. */
8840 tree
8844 {
8845 tree ret;
8851 }
8853 /* Returns true iff standard conversion sequence ICS1 is a proper
8854 subsequence of ICS2. */
8856 static bool
8858 {
8859 /* We can assume that a conversion of the same code
8860 between the same types indicates a subsequence since we only get
8861 here if the types we are converting from are the same. */
8868 {
8878 /* At this point, ICS1 cannot be a proper subsequence of
8879 ICS2. We can get a USER_CONV when we are comparing the
8880 second standard conversion sequence of two user conversion
8881 sequences. */
8896 }
8897 }
8899 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8900 be any _TYPE nodes. */
8902 bool
8904 {
8908 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8909 considers every class derived from itself. */
8912 }
8914 /* We build the ICS for an implicit object parameter as a pointer
8915 conversion sequence. However, such a sequence should be compared
8916 as if it were a reference conversion sequence. If ICS is the
8917 implicit conversion sequence for an implicit object parameter,
8918 modify it accordingly. */
8920 static void
8922 {
8924 {
8925 /* [over.match.funcs]
8927 For non-static member functions, the type of the
8928 implicit object parameter is "reference to cv X"
8929 where X is the class of which the function is a
8930 member and cv is the cv-qualification on the member
8931 function declaration. */
8933 tree reference_type;
8935 /* The `this' parameter is a pointer to a class type. Make the
8936 implicit conversion talk about a reference to that same class
8937 type. */
8950 }
8951 }
8953 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8954 and return the initial reference binding conversion. Otherwise,
8955 leave *ICS unchanged and return NULL. */
8959 {
8961 {
8966 }
8969 }
8971 /* Compare two implicit conversion sequences according to the rules set out in
8972 [over.ics.rank]. Return values:
8974 1: ics1 is better than ics2
8975 -1: ics2 is better than ics1
8976 0: ics1 and ics2 are indistinguishable */
8978 static int
8980 {
8981 tree from_type1;
8982 tree from_type2;
8983 tree to_type1;
8984 tree to_type2;
8991 /* REF_BINDING is nonzero if the result of the conversion sequence
8992 is a reference type. In that case REF_CONV is the reference
8993 binding conversion. */
8997 /* Compare badness before stripping the reference conversion. */
9003 /* Handle implicit object parameters. */
9007 /* Handle reference parameters. */
9011 /* List-initialization sequence L1 is a better conversion sequence than
9012 list-initialization sequence L2 if L1 converts to
9013 std::initializer_list<X> for some X and L2 does not. */
9019 /* [over.ics.rank]
9021 When comparing the basic forms of implicit conversion sequences (as
9022 defined in _over.best.ics_)
9024 --a standard conversion sequence (_over.ics.scs_) is a better
9025 conversion sequence than a user-defined conversion sequence
9026 or an ellipsis conversion sequence, and
9028 --a user-defined conversion sequence (_over.ics.user_) is a
9029 better conversion sequence than an ellipsis conversion sequence
9030 (_over.ics.ellipsis_). */
9031 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9032 mismatch. If both ICS are bad, we try to make a decision based on
9033 what would have happened if they'd been good. This is not an
9034 extension, we'll still give an error when we build up the call; this
9035 just helps us give a more helpful error message. */
9045 /* Both conversions are ellipsis conversions. */
9048 /* User-defined conversion sequence U1 is a better conversion sequence
9049 than another user-defined conversion sequence U2 if they contain the
9050 same user-defined conversion operator or constructor and if the sec-
9051 ond standard conversion sequence of U1 is better than the second
9052 standard conversion sequence of U2. */
9054 /* Handle list-conversion with the same code even though it isn't always
9055 ranked as a user-defined conversion and it doesn't have a second
9056 standard conversion sequence; it will still have the desired effect.
9057 Specifically, we need to do the reference binding comparison at the
9058 end of this function. */
9061 {
9077 {
9080 }
9081 else
9082 {
9083 /* For ambiguous or aggregate conversions, use the target type as
9084 a proxy for the conversion function. */
9087 }
9089 /* We can just fall through here, after setting up
9090 FROM_TYPE1 and FROM_TYPE2. */
9093 }
9094 else
9095 {
9099 /* We're dealing with two standard conversion sequences.
9101 [over.ics.rank]
9103 Standard conversion sequence S1 is a better conversion
9104 sequence than standard conversion sequence S2 if
9106 --S1 is a proper subsequence of S2 (comparing the conversion
9107 sequences in the canonical form defined by _over.ics.scs_,
9108 excluding any Lvalue Transformation; the identity
9109 conversion sequence is considered to be a subsequence of
9110 any non-identity conversion sequence */
9121 }
9123 /* One sequence can only be a subsequence of the other if they start with
9124 the same type. They can start with different types when comparing the
9125 second standard conversion sequence in two user-defined conversion
9126 sequences. */
9128 {
9133 }
9135 /* [over.ics.rank]
9137 Or, if not that,
9139 --the rank of S1 is better than the rank of S2 (by the rules
9140 defined below):
9142 Standard conversion sequences are ordered by their ranks: an Exact
9143 Match is a better conversion than a Promotion, which is a better
9144 conversion than a Conversion.
9146 Two conversion sequences with the same rank are indistinguishable
9147 unless one of the following rules applies:
9149 --A conversion that does not a convert a pointer, pointer to member,
9150 or std::nullptr_t to bool is better than one that does.
9152 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9153 so that we do not have to check it explicitly. */
9162 /* A conversion from scalar arithmetic type to complex is worse than a
9163 conversion between scalar arithmetic types. */
9170 {
9173 else
9175 }
9181 {
9186 }
9187 /* The rules for pointers to members A::* are just like the rules
9188 for pointers A*, except opposite: if B is derived from A then
9189 A::* converts to B::*, not vice versa. For that reason, we
9190 switch the from_ and to_ variables here. */
9197 {
9202 }
9207 {
9208 /* This was one of the pointer or pointer-like conversions.
9210 [over.ics.rank]
9212 --If class B is derived directly or indirectly from class A,
9213 conversion of B* to A* is better than conversion of B* to
9214 void*, and conversion of A* to void* is better than
9215 conversion of B* to void*. */
9218 {
9220 deref_from_type2))
9223 deref_from_type1))
9225 }
9228 {
9230 {
9232 {
9234 deref_to_type1))
9236 }
9237 /* We know that DEREF_TO_TYPE1 is `void' here. */
9239 deref_to_type2))
9241 }
9242 }
9245 {
9246 /* [over.ics.rank]
9248 --If class B is derived directly or indirectly from class A
9249 and class C is derived directly or indirectly from B,
9251 --conversion of C* to B* is better than conversion of C* to
9252 A*,
9254 --conversion of B* to A* is better than conversion of C* to
9255 A* */
9257 {
9259 deref_to_type2))
9262 deref_to_type1))
9264 }
9266 {
9268 deref_from_type1))
9271 deref_from_type2))
9273 }
9274 }
9275 }
9278 {
9281 /* [over.ics.rank]
9283 --binding of an expression of type C to a reference of type
9284 B& is better than binding an expression of type C to a
9285 reference of type A&
9287 --conversion of C to B is better than conversion of C to A, */
9290 {
9295 }
9296 }
9299 {
9302 /* [over.ics.rank]
9304 --binding of an expression of type B to a reference of type
9305 A& is better than binding an expression of type C to a
9306 reference of type A&,
9308 --conversion of B to A is better than conversion of C to A */
9311 {
9316 }
9317 }
9319 /* [over.ics.rank]
9321 --S1 and S2 differ only in their qualification conversion and yield
9322 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9323 qualification signature of type T1 is a proper subset of the cv-
9324 qualification signature of type T2 */
9328 {
9332 }
9334 /* [over.ics.rank]
9336 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9337 to an implicit object parameter of a non-static member function
9338 declared without a ref-qualifier, and either S1 binds an lvalue
9339 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9340 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9341 draft standard, 13.3.3.2)
9343 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9344 types to which the references refer are the same type except for
9345 top-level cv-qualifiers, and the type to which the reference
9346 initialized by S2 refers is more cv-qualified than the type to
9347 which the reference initialized by S1 refers.
9349 DR 1328 [over.match.best]: the context is an initialization by
9350 conversion function for direct reference binding (13.3.1.6) of a
9351 reference to function type, the return type of F1 is the same kind of
9352 reference (i.e. lvalue or rvalue) as the reference being initialized,
9353 and the return type of F2 is not. */
9356 {
9363 {
9367 /* Don't prefer a bad conversion that drops cv-quals to a bad
9368 conversion with the wrong rvalueness. */
9372 }
9375 {
9379 {
9380 /* Prefer the one that drops fewer cv-quals. */
9385 }
9387 }
9388 }
9390 /* Neither conversion sequence is better than the other. */
9392 }
9394 /* The source type for this standard conversion sequence. */
9396 static tree
9398 {
9400 {
9405 }
9407 }
9409 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9410 a pointer to LOSER and re-running joust to produce the warning if WINNER
9411 is actually used. */
9413 static void
9415 {
9421 }
9423 /* Compare two candidates for overloading as described in
9424 [over.match.best]. Return values:
9426 1: cand1 is better than cand2
9427 -1: cand2 is better than cand1
9428 0: cand1 and cand2 are indistinguishable */
9430 static int
9432 tsubst_flags_t complain)
9433 {
9439 /* Candidates that involve bad conversions are always worse than those
9440 that don't. */
9446 /* If we have two pseudo-candidates for conversions to the same type,
9447 or two candidates for the same function, arbitrarily pick one. */
9452 /* Prefer a non-deleted function over an implicitly deleted move
9453 constructor or assignment operator. This differs slightly from the
9454 wording for issue 1402 (which says the move op is ignored by overload
9455 resolution), but this way produces better error messages. */
9459 {
9466 }
9468 /* a viable function F1
9469 is defined to be a better function than another viable function F2 if
9470 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9471 ICSi(F2), and then */
9473 /* for some argument j, ICSj(F1) is a better conversion sequence than
9474 ICSj(F2) */
9476 /* For comparing static and non-static member functions, we ignore
9477 the implicit object parameter of the non-static function. The
9478 standard says to pretend that the static function has an object
9479 parm, but that won't work with operator overloading. */
9482 {
9488 /* We're comparing a near-match list constructor and a near-match
9489 non-list constructor. Just treat them as unordered. */
9496 else
9497 {
9500 }
9501 }
9504 {
9510 {
9512 && warn_sign_promo
9524 {
9531 else
9536 {
9540 }
9541 else
9543 }
9546 {
9549 }
9551 }
9552 }
9554 /* warn about confusing overload resolution for user-defined conversions,
9555 either between a constructor and a conversion op, or between two
9556 conversion ops. */
9561 {
9567 else
9570 /* We don't want to complain about `X::operator T1 ()'
9571 beating `X::operator T2 () const', when T2 is a no less
9572 cv-qualified version of T1. */
9575 {
9580 {
9583 }
9586 }
9587 else
9593 {
9600 {
9602 }
9603 }
9604 else
9606 }
9611 /* DR 495 moved this tiebreaker above the template ones. */
9612 /* or, if not that,
9613 the context is an initialization by user-defined conversion (see
9614 _dcl.init_ and _over.match.user_) and the standard conversion
9615 sequence from the return type of F1 to the destination type (i.e.,
9616 the type of the entity being initialized) is a better conversion
9617 sequence than the standard conversion sequence from the return type
9618 of F2 to the destination type. */
9621 {
9625 }
9627 /* or, if not that,
9628 F1 is a non-template function and F2 is a template function
9629 specialization. */
9636 /* or, if not that,
9637 F1 and F2 are template functions and the function template for F1 is
9638 more specialized than the template for F2 according to the partial
9639 ordering rules. */
9642 {
9643 winner = more_specialized_fn
9646 /* [temp.func.order]: The presence of unused ellipsis and default
9647 arguments has no effect on the partial ordering of function
9648 templates. add_function_candidate() will not have
9649 counted the "this" argument for constructors. */
9653 }
9655 // C++ Concepts
9656 // or, if not that, F1 is more constrained than F2.
9658 {
9662 }
9664 /* or, if not that, F2 is from a using-declaration, F1 is not, and the
9665 conversion sequences are equivalent.
9666 (proposed in http://lists.isocpp.org/core/2016/10/1142.php) */
9671 {
9679 {
9681 {
9686 }
9689 }
9690 }
9692 /* Check whether we can discard a builtin candidate, either because we
9693 have two identical ones or matching builtin and non-builtin candidates.
9695 (Pedantically in the latter case the builtin which matched the user
9696 function should not be added to the overload set, but we spot it here.
9698 [over.match.oper]
9699 ... the builtin candidates include ...
9700 - do not have the same parameter type list as any non-template
9701 non-member candidate. */
9704 {
9710 {
9712 /* Two built-in candidates; arbitrarily pick one. */
9715 /* cand1 is built-in; prefer cand2. */
9717 else
9718 /* cand2 is built-in; prefer cand1. */
9720 }
9721 }
9723 /* For candidates of a multi-versioned function, make the version with
9724 the highest priority win. This version will be checked for dispatching
9725 first. If this version can be inlined into the caller, the front-end
9726 will simply make a direct call to this function. */
9732 {
9738 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9739 is possible that cand1->fn and cand2->fn are function versions but of
9740 different functions. Check types to see if they are versions of the same
9741 function. */
9744 {
9745 /* Always make the version with the higher priority, more
9746 specialized, win. */
9750 else
9752 }
9753 }
9755 /* If the two function declarations represent the same function (this can
9756 happen with declarations in multiple scopes and arg-dependent lookup),
9757 arbitrarily choose one. But first make sure the default args we're
9758 using match. */
9761 {
9768 {
9769 /* Don't crash if the fn is variadic. */
9774 }
9782 {
9785 {
9787 {
9789 {
9791 "default argument mismatch in "
9793 {
9798 }
9799 }
9800 else
9802 }
9803 else
9806 }
9809 }
9812 }
9814 tweak:
9816 /* Extension: If the worst conversion for one candidate is worse than the
9817 worst conversion for the other, take the first. */
9819 {
9824 {
9829 }
9835 {
9836 /* Don't choose a deleted function over ambiguity. */
9840 {
9842 "ISO C++ says that these are ambiguous, even "
9843 "though the worst conversion for the first is better than "
9847 }
9848 else
9851 }
9852 }
9856 }
9858 /* Given a list of candidates for overloading, find the best one, if any.
9859 This algorithm has a worst case of O(2n) (winner is last), and a best
9860 case of O(n/2) (totally ambiguous); much better than a sorting
9861 algorithm. */
9865 {
9870 /* Walk through the list once, comparing each current champ to the next
9871 candidate, knocking out a candidate or two with each comparison. */
9874 {
9878 else
9879 {
9881 {
9886 }
9887 else
9888 {
9891 }
9894 }
9895 }
9897 /* Make sure the champ is better than all the candidates it hasn't yet
9898 been compared to. */
9901 challenger != champ
9904 {
9908 }
9911 }
9913 /* Returns nonzero if things of type FROM can be converted to TO. */
9915 bool
9917 {
9919 /* implicit_conversion only considers user-defined conversions
9920 if it has an expression for the call argument list. */
9924 }
9926 /* Returns nonzero if things of type FROM can be converted to TO with a
9927 standard conversion. */
9929 bool
9931 {
9933 }
9935 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9937 bool
9939 tsubst_flags_t complain)
9940 {
9945 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9947 /* We want to discard any access checks done for this test,
9948 as we might not be in the appropriate access context and
9949 we'll do the check again when we actually perform the
9950 conversion. */
9957 /* Discard the access checks now. */
9959 /* Free all the conversions we allocated. */
9963 }
9965 /* Like can_convert_arg, but allows dubious conversions as well. */
9967 bool
9969 tsubst_flags_t complain)
9970 {
9974 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9976 /* Try to perform the conversion. */
9979 /* Free all the conversions we allocated. */
9983 }
9985 /* Convert EXPR to TYPE. Return the converted expression.
9987 Note that we allow bad conversions here because by the time we get to
9988 this point we are committed to doing the conversion. If we end up
9989 doing a bad conversion, convert_like will complain. */
9991 tree
9994 {
10002 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10010 {
10012 {
10013 /* If expr has unknown type, then it is an overloaded function.
10014 Call instantiate_type to get good error messages. */
10019 else
10022 }
10024 }
10026 {
10027 /* In a template, we are only concerned about determining the
10028 type of non-dependent expressions, so we do not have to
10029 perform the actual conversion. But for initializers, we
10030 need to be able to perform it at instantiation
10031 (or instantiate_non_dependent_expr) time. */
10035 }
10036 else
10039 /* Free all the conversions we allocated. */
10043 }
10045 tree
10047 {
10049 LOOKUP_IMPLICIT);
10050 }
10052 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10053 permitted. If the conversion is valid, the converted expression is
10054 returned. Otherwise, NULL_TREE is returned, except in the case
10055 that TYPE is a class type; in that case, an error is issued. If
10056 C_CAST_P is true, then this direct-initialization is taking
10057 place as part of a static_cast being attempted as part of a C-style
10058 cast. */
10060 tree
10062 tree expr,
10064 tsubst_flags_t complain)
10065 {
10071 /* [dcl.init]
10073 If the destination type is a (possibly cv-qualified) class type:
10075 -- If the initialization is direct-initialization ...,
10076 constructors are considered. ... If no constructor applies, or
10077 the overload resolution is ambiguous, the initialization is
10078 ill-formed. */
10080 {
10086 }
10088 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10092 c_cast_p,
10096 else
10099 c_cast_p,
10100 complain);
10102 /* Free all the conversions we allocated. */
10106 }
10108 /* When initializing a reference that lasts longer than a full-expression,
10109 this special rule applies:
10111 [class.temporary]
10113 The temporary to which the reference is bound or the temporary
10114 that is the complete object to which the reference is bound
10115 persists for the lifetime of the reference.
10117 The temporaries created during the evaluation of the expression
10118 initializing the reference, except the temporary to which the
10119 reference is bound, are destroyed at the end of the
10120 full-expression in which they are created.
10122 In that case, we store the converted expression into a new
10123 VAR_DECL in a new scope.
10125 However, we want to be careful not to create temporaries when
10126 they are not required. For example, given:
10128 struct B {};
10129 struct D : public B {};
10130 D f();
10131 const B& b = f();
10133 there is no need to copy the return value from "f"; we can just
10134 extend its lifetime. Similarly, given:
10136 struct S {};
10137 struct T { operator S(); };
10138 T t;
10139 const S& s = t;
10141 we can extend the lifetime of the return value of the conversion
10142 operator.
10144 The next several functions are involved in this lifetime extension. */
10146 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10147 reference is being bound to a temporary. Create and return a new
10148 VAR_DECL with the indicated TYPE; this variable will store the value to
10149 which the reference is bound. */
10151 tree
10153 {
10154 tree var;
10156 /* Create the variable. */
10159 /* Register the variable. */
10162 {
10163 /* Namespace-scope or local static; give it a mangled name. */
10164 /* FIXME share comdat with decl? */
10165 tree name;
10174 }
10175 else
10176 /* Create a new cleanup level if necessary. */
10180 }
10182 /* EXPR is the initializer for a variable DECL of reference or
10183 std::initializer_list type. Create, push and return a new VAR_DECL
10184 for the initializer so that it will live as long as DECL. Any
10185 cleanup for the new variable is returned through CLEANUP, and the
10186 code to initialize the new variable is returned through INITP. */
10188 static tree
10191 {
10192 tree init;
10193 tree type;
10194 tree var;
10196 /* Create the temporary variable. */
10200 /* If the rvalue is the result of a function call it will be
10201 a TARGET_EXPR. If it is some other construct (such as a
10202 member access expression where the underlying object is
10203 itself the result of a function call), turn it into a
10204 TARGET_EXPR here. It is important that EXPR be a
10205 TARGET_EXPR below since otherwise the INIT_EXPR will
10206 attempt to make a bitwise copy of EXPR to initialize
10207 VAR. */
10213 {
10217 }
10219 /* Recursively extend temps in this initializer. */
10223 /* Any reference temp has a non-trivial initializer. */
10226 /* If the initializer is constant, put it in DECL_INITIAL so we get
10227 static initialization and use in constant expressions. */
10230 {
10232 {
10233 /* 5.19 says that a constant expression can include an
10234 lvalue-rvalue conversion applied to "a glvalue of literal type
10235 that refers to a non-volatile temporary object initialized
10236 with a constant expression". Rather than try to communicate
10237 that this VAR_DECL is a temporary, just mark it constexpr.
10239 Currently this is only useful for initializer_list temporaries,
10240 since reference vars can't appear in constant expressions. */
10244 }
10247 }
10248 else
10249 /* Create the INIT_EXPR that will initialize the temporary
10250 variable. */
10253 {
10258 else
10259 {
10263 }
10265 /* We must be careful to destroy the temporary only
10266 after its initialization has taken place. If the
10267 initialization throws an exception, then the
10268 destructor should not be run. We cannot simply
10269 transform INIT into something like:
10271 (INIT, ({ CLEANUP_STMT; }))
10273 because emit_local_var always treats the
10274 initializer as a full-expression. Thus, the
10275 destructor would run too early; it would run at the
10276 end of initializing the reference variable, rather
10277 than at the end of the block enclosing the
10278 reference variable.
10280 The solution is to pass back a cleanup expression
10281 which the caller is responsible for attaching to
10282 the statement tree. */
10283 }
10284 else
10285 {
10288 {
10291 tls_aggregates);
10292 else
10294 static_aggregates);
10295 }
10296 else
10297 /* Check whether the dtor is callable. */
10299 }
10300 /* Avoid -Wunused-variable warning (c++/38958). */
10307 }
10309 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10310 initializing a variable of that TYPE. */
10312 tree
10315 {
10323 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10329 {
10331 {
10340 else
10344 }
10346 }
10349 /* Perform the conversion. */
10352 /* We gave an error in build_user_type_conversion_1. */
10354 else
10357 /* Free all the conversions we allocated. */
10361 }
10363 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10364 which is bound either to a reference or a std::initializer_list. */
10366 static tree
10368 {
10373 {
10377 }
10380 /* Deal with binding to a subobject. */
10384 {
10392 }
10394 }
10396 /* INIT is part of the initializer for DECL. If there are any
10397 reference or initializer lists being initialized, extend their
10398 lifetime to match that of DECL. */
10400 tree
10402 {
10408 else
10409 {
10414 {
10416 {
10417 /* The temporary array underlying a std::initializer_list
10418 is handled like a reference temporary. */
10422 }
10423 else
10424 {
10430 }
10431 }
10432 }
10435 }
10437 /* Returns true iff an initializer for TYPE could contain temporaries that
10438 need to be extended because they are bound to references or
10439 std::initializer_list. */
10441 bool
10443 {
10448 {
10455 }
10457 }
10459 /* Returns true iff TYPE is some variant of std::initializer_list. */
10461 bool
10463 {
10464 /* Look through typedefs. */
10473 }
10475 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10476 will accept an argument list of a single std::initializer_list<T>. */
10478 bool
10480 {
10482 tree arg;
10494 /* There are more non-defaulted parms. */
10498 }