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1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2017 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, \
153 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
154 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), \
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 {
1268 && (same_type_ignoring_top_level_qualifiers_p
1270 {
1273 }
1274 else
1276 }
1279 /* [conv.ptr]
1281 An rvalue of type "pointer to cv D," where D is a
1282 class type, can be converted to an rvalue of type
1283 "pointer to cv B," where B is a base class (clause
1284 _class.derived_) of D. If B is an inaccessible
1285 (clause _class.access_) or ambiguous
1286 (_class.member.lookup_) base class of D, a program
1287 that necessitates this conversion is ill-formed.
1288 Therefore, we use DERIVED_FROM_P, and do not check
1289 access or uniqueness. */
1291 {
1292 from_pointee
1298 }
1303 /* In a C-style cast, we ignore CV-qualification because we
1304 are allowed to perform a static_cast followed by a
1305 const_cast. */
1310 /* converting from string constant to char *. */
1314 /* Allow conversions among compatible ObjC pointer types (base
1315 conversions have been already handled above). */
1320 {
1323 }
1324 else
1328 }
1330 {
1344 else
1348 {
1350 tbase,
1356 }
1359 }
1361 {
1362 /* [conv.bool]
1364 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1365 to member type can be converted to a prvalue of type bool. ...
1366 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1367 std::nullptr_t can be converted to a prvalue of type bool; */
1373 {
1384 }
1387 }
1388 /* We don't check for ENUMERAL_TYPE here because there are no standard
1389 conversions to enum type. */
1390 /* As an extension, allow conversion to complex type. */
1392 {
1399 /* Give this a better rank if it's a promotion. */
1403 }
1409 {
1413 /* The derived-to-base conversion indicates the initialization
1414 of a parameter with base type from an object of a derived
1415 type. A temporary object is created to hold the result of
1416 the conversion unless we're binding directly to a reference. */
1418 }
1419 else
1426 }
1428 /* Returns nonzero if T1 is reference-related to T2. */
1430 bool
1432 {
1439 /* [dcl.init.ref]
1441 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1442 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1443 of T2. */
1447 }
1449 /* Returns nonzero if T1 is reference-compatible with T2. */
1451 static bool
1453 {
1454 /* [dcl.init.ref]
1456 "cv1 T1" is reference compatible with "cv2 T2" if
1457 * T1 is reference-related to T2 or
1458 * T2 is "noexcept function" and T1 is "function", where the
1459 function types are otherwise the same,
1460 and cv1 is the same cv-qualification as, or greater cv-qualification
1461 than, cv2. */
1465 }
1467 /* A reference of the indicated TYPE is being bound directly to the
1468 expression represented by the implicit conversion sequence CONV.
1469 Return a conversion sequence for this binding. */
1473 {
1474 tree t;
1481 /* [over.ics.rank]
1483 When a parameter of reference type binds directly
1484 (_dcl.init.ref_) to an argument expression, the implicit
1485 conversion sequence is the identity conversion, unless the
1486 argument expression has a type that is a derived class of the
1487 parameter type, in which case the implicit conversion sequence is
1488 a derived-to-base Conversion.
1490 If the parameter binds directly to the result of applying a
1491 conversion function to the argument expression, the implicit
1492 conversion sequence is a user-defined conversion sequence
1493 (_over.ics.user_), with the second standard conversion sequence
1494 either an identity conversion or, if the conversion function
1495 returns an entity of a type that is a derived class of the
1496 parameter type, a derived-to-base conversion. */
1498 {
1499 /* Represent the derived-to-base conversion. */
1501 /* We will actually be binding to the base-class subobject in
1502 the derived class, so we mark this conversion appropriately.
1503 That way, convert_like knows not to generate a temporary. */
1505 }
1507 }
1509 /* Returns the conversion path from type FROM to reference type TO for
1510 purposes of reference binding. For lvalue binding, either pass a
1511 reference type to FROM or an lvalue expression to EXPR. If the
1512 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1513 the conversion returned. If C_CAST_P is true, this
1514 conversion is coming from a C-style cast. */
1518 tsubst_flags_t complain)
1519 {
1523 tree tfrom;
1526 cp_lvalue_kind gl_kind;
1530 {
1535 }
1538 {
1540 /* DR 1288: Otherwise, if the initializer list has a single element
1541 of type E and ... [T's] referenced type is reference-related to E,
1542 the object or reference is initialized from that element... */
1544 {
1550 {
1554 }
1555 }
1556 /* Otherwise, if T is a reference type, a prvalue temporary of the
1557 type referenced by T is copy-list-initialized or
1558 direct-list-initialized, depending on the kind of initialization
1559 for the reference, and the reference is bound to that temporary. */
1562 skip:;
1563 }
1566 {
1571 else
1573 }
1579 else
1582 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1587 /* Same mask as real_lvalue_p. */
1594 /* Figure out whether or not the types are reference-related and
1595 reference compatible. We have to do this after stripping
1596 references from FROM. */
1598 /* If this is a C cast, first convert to an appropriately qualified
1599 type, so that we can later do a const_cast to the desired type. */
1605 /* Directly bind reference when target expression's type is compatible with
1606 the reference and expression is an lvalue. In DR391, the wording in
1607 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1608 const and rvalue references to rvalues of compatible class type.
1609 We should also do direct bindings for non-class xvalues. */
1611 {
1612 /* [dcl.init.ref]
1614 If the initializer expression
1616 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1617 is reference-compatible with "cv2 T2,"
1619 the reference is bound directly to the initializer expression
1620 lvalue.
1622 [...]
1623 If the initializer expression is an rvalue, with T2 a class type,
1624 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1625 is bound to the object represented by the rvalue or to a sub-object
1626 within that object. */
1632 /* The top-level caller requested that we pretend that the lvalue
1633 be treated as an rvalue. */
1636 /* Handle rvalue reference to function properly. */
1637 conv->rvaluedness_matches_p
1639 else
1640 conv->rvaluedness_matches_p
1645 /* For the purposes of overload resolution, we ignore the fact
1646 this expression is a bitfield or packed field. (In particular,
1647 [over.ics.ref] says specifically that a function with a
1648 non-const reference parameter is viable even if the
1649 argument is a bitfield.)
1651 However, when we actually call the function we must create
1652 a temporary to which to bind the reference. If the
1653 reference is volatile, or isn't const, then we cannot make
1654 a temporary, so we just issue an error when the conversion
1655 actually occurs. */
1658 /* Don't allow binding of lvalues (other than function lvalues) to
1659 rvalue references. */
1665 /* Nor the reverse. */
1676 }
1677 /* [class.conv.fct] A conversion function is never used to convert a
1678 (possibly cv-qualified) object to the (possibly cv-qualified) same
1679 object type (or a reference to it), to a (possibly cv-qualified) base
1680 class of that type (or a reference to it).... */
1683 {
1684 /* [dcl.init.ref]
1686 If the initializer expression
1688 -- has a class type (i.e., T2 is a class type) can be
1689 implicitly converted to an lvalue of type "cv3 T3," where
1690 "cv1 T1" is reference-compatible with "cv3 T3". (this
1691 conversion is selected by enumerating the applicable
1692 conversion functions (_over.match.ref_) and choosing the
1693 best one through overload resolution. (_over.match_).
1695 the reference is bound to the lvalue result of the conversion
1696 in the second case. */
1698 complain);
1701 }
1703 /* From this point on, we conceptually need temporaries, even if we
1704 elide them. Only the cases above are "direct bindings". */
1708 /* [over.ics.rank]
1710 When a parameter of reference type is not bound directly to an
1711 argument expression, the conversion sequence is the one required
1712 to convert the argument expression to the underlying type of the
1713 reference according to _over.best.ics_. Conceptually, this
1714 conversion sequence corresponds to copy-initializing a temporary
1715 of the underlying type with the argument expression. Any
1716 difference in top-level cv-qualification is subsumed by the
1717 initialization itself and does not constitute a conversion. */
1719 /* [dcl.init.ref]
1721 Otherwise, the reference shall be an lvalue reference to a
1722 non-volatile const type, or the reference shall be an rvalue
1723 reference.
1725 We try below to treat this as a bad conversion to improve diagnostics,
1726 but if TO is an incomplete class, we need to reject this conversion
1727 now to avoid unnecessary instantiation. */
1732 /* We're generating a temporary now, but don't bind any more in the
1733 conversion (specifically, don't slice the temporary returned by a
1734 conversion operator). */
1737 /* Core issue 899: When [copy-]initializing a temporary to be bound
1738 to the first parameter of a copy constructor (12.8) called with
1739 a single argument in the context of direct-initialization,
1740 explicit conversion functions are also considered.
1742 So don't set LOOKUP_ONLYCONVERTING in that case. */
1753 {
1754 /* If initializing the temporary used a conversion function,
1755 recalculate the second conversion sequence. */
1759 {
1762 conversion *new_second
1768 }
1769 }
1772 /* This reference binding, unlike those above, requires the
1773 creation of a temporary. */
1777 /* [dcl.init.ref]
1779 Otherwise, the reference shall be an lvalue reference to a
1780 non-volatile const type, or the reference shall be an rvalue
1781 reference. */
1785 /* [dcl.init.ref]
1787 Otherwise, a temporary of type "cv1 T1" is created and
1788 initialized from the initializer expression using the rules for a
1789 non-reference copy initialization. If T1 is reference-related to
1790 T2, cv1 must be the same cv-qualification as, or greater
1791 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1796 }
1798 /* Returns the implicit conversion sequence (see [over.ics]) from type
1799 FROM to type TO. The optional expression EXPR may affect the
1800 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1801 true, this conversion is coming from a C-style cast. */
1806 {
1813 /* Other flags only apply to the primary function in overload
1814 resolution, or after we've chosen one. */
1819 /* FIXME: actually we don't want warnings either, but we can't just
1820 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1821 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1822 We really ought not to issue that warning until we've committed
1823 to that conversion. */
1826 /* Call reshape_init early to remove redundant braces. */
1831 {
1836 }
1840 else
1847 {
1851 /* As an extension, allow list-initialization of _Complex. */
1853 {
1857 }
1859 /* Allow conversion from an initializer-list with one element to a
1860 scalar type. */
1862 {
1864 tree elt;
1870 else
1876 {
1879 /* Too many levels of braces, i.e. '{{1}}'. */
1882 }
1883 }
1886 }
1892 {
1902 {
1906 {
1907 /* "If C is not an initializer-list constructor and the
1908 initializer list has a single element of type cv U, where U is
1909 X or a class derived from X, the implicit conversion sequence
1910 has Exact Match rank if U is X, or Conversion rank if U is
1911 derived from X." */
1917 }
1919 }
1921 /* We used to try to bind a reference to a temporary here, but that
1922 is now handled after the recursive call to this function at the end
1923 of reference_binding. */
1925 }
1928 }
1930 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1931 functions. ARGS will not be changed until a single candidate is
1932 selected. */
1941 {
1959 }
1961 /* Return the number of remaining arguments in the parameter list
1962 beginning with ARG. */
1964 int
1966 {
1971 n++;
1974 }
1976 /* Create an overload candidate for the function or method FN called
1977 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1978 FLAGS is passed on to implicit_conversion.
1980 This does not change ARGS.
1982 CTYPE, if non-NULL, is the type we want to pretend this function
1983 comes from for purposes of overload resolution. */
1990 tsubst_flags_t complain)
1991 {
1995 tree parmnode;
2001 /* At this point we should not see any functions which haven't been
2002 explicitly declared, except for friend functions which will have
2003 been found using argument dependent lookup. */
2006 /* The `this', `in_chrg' and VTT arguments to constructors are not
2007 considered in overload resolution. */
2009 {
2011 /* Bring back parameters omitted from an inherited ctor. */
2013 else
2017 {
2020 }
2021 }
2022 else
2028 /* 13.3.2 - Viable functions [over.match.viable]
2029 First, to be a viable function, a candidate function shall have enough
2030 parameters to agree in number with the arguments in the list.
2032 We need to check this first; otherwise, checking the ICSes might cause
2033 us to produce an ill-formed template instantiation. */
2037 {
2041 }
2045 {
2049 }
2051 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2052 parameter of type "reference to cv C" (including such a constructor
2053 instantiated from a template) is excluded from the set of candidate
2054 functions when used to construct an object of type D with an argument list
2055 containing a single argument if C is reference-related to D. */
2057 && flag_new_inheriting_ctors
2059 {
2065 {
2068 }
2069 }
2071 /* Second, for a function to be viable, its constraints must be
2072 satisfied. */
2075 {
2078 }
2080 /* When looking for a function from a subobject from an implicit
2081 copy/move constructor/operator=, don't consider anything that takes (a
2082 reference to) an unrelated type. See c++/44909 and core 1092. */
2084 {
2090 else
2093 {
2096 ctype))
2098 }
2100 /* This only applies at the top level. */
2102 }
2107 /* Third, for F to be a viable function, there shall exist for each
2108 argument an implicit conversion sequence that converts that argument
2109 to the corresponding parameter of F. */
2114 {
2116 tree arg;
2125 else
2134 {
2140 /* The type of the implicit object parameter ('this') for
2141 overload resolution is not always the same as for the
2142 function itself; conversion functions are considered to
2143 be members of the class being converted, and functions
2144 introduced by a using-declaration are considered to be
2145 members of the class that uses them.
2147 Since build_over_call ignores the ICS for the `this'
2148 parameter, we can just change the parm type. */
2150 {
2151 parmtype = cp_build_qualified_type
2154 {
2155 /* If the function has a ref-qualifier, the implicit
2156 object parameter has reference type. */
2159 /* The special handling of 'this' conversions in compare_ics
2160 does not apply if there is a ref-qualifier. */
2162 }
2163 else
2164 {
2168 }
2169 }
2171 /* Core issue 899: When [copy-]initializing a temporary to be bound
2172 to the first parameter of a copy constructor (12.8) called with
2173 a single argument in the context of direct-initialization,
2174 explicit conversion functions are also considered.
2176 So set LOOKUP_COPY_PARM to let reference_binding know that
2177 it's being called in that context. We generalize the above
2178 to handle move constructors and template constructors as well;
2179 the standardese should soon be updated similarly. */
2183 && (same_type_ignoring_top_level_qualifiers_p
2185 {
2188 /* We allow user-defined conversions within init-lists, but
2189 don't list-initialize the copy parm, as that would mean
2190 using two levels of braces for the same type. */
2194 }
2195 else
2201 }
2202 else
2203 {
2207 }
2214 {
2218 }
2221 {
2224 }
2225 }
2227 out:
2230 }
2232 /* Create an overload candidate for the conversion function FN which will
2233 be invoked for expression OBJ, producing a pointer-to-function which
2234 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2235 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2236 passed on to implicit_conversion.
2238 Actually, we don't really care about FN; we care about the type it
2239 converts to. There may be multiple conversion functions that will
2240 convert to that type, and we rely on build_user_type_conversion_1 to
2241 choose the best one; so when we create our candidate, we record the type
2242 instead of the function. */
2248 tsubst_flags_t complain)
2249 {
2267 /* Don't bother looking up the same type twice. */
2272 {
2278 else
2283 {
2287 }
2291 {
2295 }
2296 else
2297 {
2301 }
2308 {
2311 }
2318 }
2322 {
2326 }
2330 }
2332 static void
2336 {
2350 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2351 conversion ops are allowed. We handle that here by just checking for
2352 boolean_type_node because other operators don't ask for it. COND_EXPR
2353 also does contextual conversion to bool for the first operand, but we
2354 handle that in build_conditional_expr, and type1 here is operand 2. */
2359 {
2366 {
2368 /* We need something for printing the candidate. */
2372 }
2374 {
2378 }
2380 }
2382 /* For COND_EXPR we rearranged the arguments; undo that now. */
2384 {
2389 complain);
2392 else
2393 {
2396 boolean_type_node);
2397 }
2398 }
2405 }
2407 static bool
2409 {
2411 }
2413 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2415 static bool
2417 {
2418 /* [over.built]
2420 In this section, the term promoted integral type is used to refer
2421 to those integral types which are preserved by integral promotion
2422 (including e.g. int and long but excluding e.g. char).
2423 Similarly, the term promoted arithmetic type refers to promoted
2424 integral types plus floating types. */
2428 }
2430 /* Create any builtin operator overload candidates for the operator in
2431 question given the converted operand types TYPE1 and TYPE2. The other
2432 args are passed through from add_builtin_candidates to
2433 build_builtin_candidate.
2435 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2436 If CODE is requires candidates operands of the same type of the kind
2437 of which TYPE1 and TYPE2 are, we add both candidates
2438 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2440 static void
2444 tsubst_flags_t complain)
2445 {
2447 {
2455 }
2458 {
2460 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2461 and VQ is either volatile or empty, there exist candidate operator
2462 functions of the form
2463 VQ T& operator++(VQ T&);
2464 T operator++(VQ T&, int);
2465 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2466 type other than bool, and VQ is either volatile or empty, there exist
2467 candidate operator functions of the form
2468 VQ T& operator--(VQ T&);
2469 T operator--(VQ T&, int);
2470 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2471 complete object type, and VQ is either volatile or empty, there exist
2472 candidate operator functions of the form
2473 T*VQ& operator++(T*VQ&);
2474 T*VQ& operator--(T*VQ&);
2475 T* operator++(T*VQ&, int);
2476 T* operator--(T*VQ&, int); */
2482 /* FALLTHRU */
2486 {
2489 }
2492 /* 7 For every cv-qualified or cv-unqualified object type T, there
2493 exist candidate operator functions of the form
2495 T& operator*(T*);
2497 8 For every function type T, there exist candidate operator functions of
2498 the form
2499 T& operator*(T*); */
2508 /* 9 For every type T, there exist candidate operator functions of the form
2509 T* operator+(T*);
2511 10For every promoted arithmetic type T, there exist candidate operator
2512 functions of the form
2513 T operator+(T);
2514 T operator-(T); */
2519 /* FALLTHRU */
2525 /* 11For every promoted integral type T, there exist candidate operator
2526 functions of the form
2527 T operator~(T); */
2534 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2535 is the same type as C2 or is a derived class of C2, T is a complete
2536 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2537 there exist candidate operator functions of the form
2538 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2539 where CV12 is the union of CV1 and CV2. */
2543 {
2551 }
2554 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2555 didate operator functions of the form
2556 LR operator*(L, R);
2557 LR operator/(L, R);
2558 LR operator+(L, R);
2559 LR operator-(L, R);
2560 bool operator<(L, R);
2561 bool operator>(L, R);
2562 bool operator<=(L, R);
2563 bool operator>=(L, R);
2564 bool operator==(L, R);
2565 bool operator!=(L, R);
2566 where LR is the result of the usual arithmetic conversions between
2567 types L and R.
2569 14For every pair of types T and I, where T is a cv-qualified or cv-
2570 unqualified complete object type and I is a promoted integral type,
2571 there exist candidate operator functions of the form
2572 T* operator+(T*, I);
2573 T& operator[](T*, I);
2574 T* operator-(T*, I);
2575 T* operator+(I, T*);
2576 T& operator[](I, T*);
2578 15For every T, where T is a pointer to complete object type, there exist
2579 candidate operator functions of the form112)
2580 ptrdiff_t operator-(T, T);
2582 16For every pointer or enumeration type T, there exist candidate operator
2583 functions of the form
2584 bool operator<(T, T);
2585 bool operator>(T, T);
2586 bool operator<=(T, T);
2587 bool operator>=(T, T);
2588 bool operator==(T, T);
2589 bool operator!=(T, T);
2591 17For every pointer to member type T, there exist candidate operator
2592 functions of the form
2593 bool operator==(T, T);
2594 bool operator!=(T, T); */
2601 {
2604 }
2605 /* FALLTHRU */
2618 {
2621 }
2623 {
2626 }
2627 /* Fall through. */
2643 {
2646 }
2649 {
2652 }
2658 /* FALLTHRU */
2661 {
2664 }
2666 {
2669 }
2672 /* 18For every pair of promoted integral types L and R, there exist candi-
2673 date operator functions of the form
2674 LR operator%(L, R);
2675 LR operator&(L, R);
2676 LR operator^(L, R);
2677 LR operator|(L, R);
2678 L operator<<(L, R);
2679 L operator>>(L, R);
2680 where LR is the result of the usual arithmetic conversions between
2681 types L and R. */
2689 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2693 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2694 type, VQ is either volatile or empty, and R is a promoted arithmetic
2695 type, there exist candidate operator functions of the form
2696 VQ L& operator=(VQ L&, R);
2697 VQ L& operator*=(VQ L&, R);
2698 VQ L& operator/=(VQ L&, R);
2699 VQ L& operator+=(VQ L&, R);
2700 VQ L& operator-=(VQ L&, R);
2702 20For every pair T, VQ), where T is any type and VQ is either volatile
2703 or empty, there exist candidate operator functions of the form
2704 T*VQ& operator=(T*VQ&, T*);
2706 21For every pair T, VQ), where T is a pointer to member type and VQ is
2707 either volatile or empty, there exist candidate operator functions of
2708 the form
2709 VQ T& operator=(VQ T&, T);
2711 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2712 unqualified complete object type, VQ is either volatile or empty, and
2713 I is a promoted integral type, there exist candidate operator func-
2714 tions of the form
2715 T*VQ& operator+=(T*VQ&, I);
2716 T*VQ& operator-=(T*VQ&, I);
2718 23For every triple L, VQ, R), where L is an integral or enumeration
2719 type, VQ is either volatile or empty, and R is a promoted integral
2720 type, there exist candidate operator functions of the form
2722 VQ L& operator%=(VQ L&, R);
2723 VQ L& operator<<=(VQ L&, R);
2724 VQ L& operator>>=(VQ L&, R);
2725 VQ L& operator&=(VQ L&, R);
2726 VQ L& operator^=(VQ L&, R);
2727 VQ L& operator|=(VQ L&, R); */
2731 {
2735 {
2738 }
2739 /* FALLTHRU */
2752 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2765 {
2768 }
2773 }
2778 /* [over.built]
2780 For every pair of promoted arithmetic types L and R, there
2781 exist candidate operator functions of the form
2783 LR operator?(bool, L, R);
2785 where LR is the result of the usual arithmetic conversions
2786 between types L and R.
2788 For every type T, where T is a pointer or pointer-to-member
2789 type, there exist candidate operator functions of the form T
2790 operator?(bool, T, T); */
2794 /* That's OK. */
2797 /* Otherwise, the types should be pointers. */
2801 /* We don't check that the two types are the same; the logic
2802 below will actually create two candidates; one in which both
2803 parameter types are TYPE1, and one in which both parameter
2804 types are TYPE2. */
2815 }
2817 /* Make sure we don't create builtin candidates with dependent types. */
2821 {
2822 /* Try to recover if one of the types is non-dependent. But if
2823 there's only one type, there's nothing we can do. */
2826 /* And we lose if both are dependent. */
2829 /* Or if they have different forms. */
2837 }
2839 /* If we're dealing with two pointer types or two enumeral types,
2840 we need candidates for both of them. */
2849 {
2851 {
2853 error_mark_node,
2854 error_mark_node,
2855 CPO_CONVERSION,
2856 tf_none);
2858 {
2859 build_builtin_candidate
2863 }
2864 }
2866 build_builtin_candidate
2868 build_builtin_candidate
2871 }
2873 build_builtin_candidate
2875 }
2877 tree
2879 {
2885 }
2887 /* There are three conditions of builtin candidates:
2889 1) bool-taking candidates. These are the same regardless of the input.
2890 2) pointer-pair taking candidates. These are generated for each type
2891 one of the input types converts to.
2892 3) arithmetic candidates. According to the standard, we should generate
2893 all of these, but I'm trying not to...
2895 Here we generate a superset of the possible candidates for this particular
2896 case. That is a subset of the full set the standard defines, plus some
2897 other cases which the standard disallows. add_builtin_candidate will
2898 filter out the invalid set. */
2900 static void
2904 {
2908 /* TYPES[i] is the set of possible builtin-operator parameter types
2909 we will consider for the Ith argument. */
2914 {
2917 else
2919 }
2922 {
2923 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2924 and VQ is either volatile or empty, there exist candidate operator
2925 functions of the form
2926 VQ T& operator++(VQ T&); */
2936 /* 24There also exist candidate operator functions of the form
2937 bool operator!(bool);
2938 bool operator&&(bool, bool);
2939 bool operator||(bool, bool); */
2942 build_builtin_candidate
2949 build_builtin_candidate
2967 /* Fall through. */
2971 }
2977 {
2979 ;
2981 {
2982 tree convs;
2990 {
2995 }
3001 {
3014 {
3020 }
3024 }
3025 }
3026 else
3027 {
3032 {
3038 }
3040 }
3041 }
3043 /* Run through the possible parameter types of both arguments,
3044 creating candidates with those parameter types. */
3046 {
3048 tree u;
3052 add_builtin_candidate
3055 else
3056 add_builtin_candidate
3059 }
3063 }
3066 /* If TMPL can be successfully instantiated as indicated by
3067 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3069 TMPL is the template. EXPLICIT_TARGS are any explicit template
3070 arguments. ARGLIST is the arguments provided at the call-site.
3071 This does not change ARGLIST. The RETURN_TYPE is the desired type
3072 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3073 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3074 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3082 tsubst_flags_t complain)
3083 {
3093 tree arg;
3095 tree fn;
3099 /* We don't do deduction on the in-charge parameter, the VTT
3100 parameter or 'this'. */
3102 {
3106 /* We're deducing for a call to the result of a template conversion
3108 else
3110 }
3115 {
3118 else
3120 }
3128 {
3129 /* 12.8/6 says, "A declaration of a constructor for a class X is
3130 ill-formed if its first parameter is of type (optionally cv-qualified)
3131 X and either there are no other parameters or else all other
3132 parameters have default arguments. A member function template is never
3133 instantiated to produce such a constructor signature."
3135 So if we're trying to copy an object of the containing class, don't
3136 consider a template constructor that has a first parameter type that
3137 is just a template parameter, as we would deduce a signature that we
3138 would then reject in the code below. */
3140 {
3145 {
3149 }
3150 }
3151 }
3158 {
3161 }
3165 {
3168 }
3173 args_without_in_chrg,
3174 nargs_without_in_chrg,
3179 {
3180 /* Don't repeat unification later if it already resulted in errors. */
3184 nargs_without_in_chrg,
3186 else
3189 }
3192 {
3195 ctype))
3196 {
3197 /* We're trying to produce a constructor with a prohibited signature,
3198 as discussed above; handle here any cases we didn't catch then,
3199 such as X(X<T>). */
3202 }
3203 }
3206 /* Aha, this is a conversion function. */
3209 else
3214 /* This situation can occur if a member template of a template
3215 class is specialized. Then, instantiate_template might return
3216 an instantiation of the specialization, in which case the
3217 DECL_TI_TEMPLATE field will point at the original
3218 specialization. For example:
3220 template <class T> struct S { template <class U> void f(U);
3221 template <> void f(int) {}; };
3222 S<double> sd;
3223 sd.f(3);
3225 Here, TMPL will be template <class U> S<double>::f(U).
3226 And, instantiate template will give us the specialization
3227 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3228 for this will point at template <class T> template <> S<T>::f(int),
3229 so that we can find the definition. For the purposes of
3230 overload resolution, however, we want the original TMPL. */
3232 else
3237 fail:
3240 }
3249 {
3250 return
3255 }
3257 /* Create an overload candidate for the conversion function template TMPL,
3258 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3259 pointer-to-function which will in turn be called with the argument list
3260 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3261 passed on to implicit_conversion. */
3265 tree obj,
3269 {
3270 /* Making this work broke PR 71117, so until the committee resolves core
3271 issue 2189, let's disable this candidate if there are any viable call
3272 operators. */
3276 return
3280 complain);
3281 }
3283 /* The CANDS are the set of candidates that were considered for
3284 overload resolution. Return the set of viable candidates, or CANDS
3285 if none are viable. If any of the candidates were viable, set
3286 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3287 considered viable only if it is strictly viable. */
3293 {
3299 /* Be strict inside templates, since build_over_call won't actually
3300 do the conversions to get pedwarns. */
3310 {
3314 {
3315 /* Be strict in the presence of a viable candidate. Also if
3316 there are template candidates, so that we get deduction errors
3317 for them instead of silently preferring a bad conversion. */
3320 {
3321 /* Put any spliced near matches back onto the main list so
3322 that we see them if there is no strict match. */
3328 }
3329 }
3332 {
3340 }
3341 else
3343 }
3346 }
3348 static bool
3350 {
3355 }
3357 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3358 words, it is about to become the "this" pointer for a member
3359 function call. Take the address of the object. */
3361 static tree
3363 {
3364 /* In a template, we are only concerned about the type of the
3365 expression, so we can take a shortcut. */
3370 }
3372 /* Returns true iff functions are equivalent. Equivalent functions are
3373 not '==' only if one is a function-local extern function or if
3374 both are extern "C". */
3378 {
3387 }
3389 /* Print information about a candidate being rejected due to INFO. */
3391 static void
3393 {
3398 {
3399 /* Conversion of implicit `this' argument failed. */
3401 /* A bad conversion for 'this' must be discarding cv-quals. */
3404 from);
3405 else
3409 }
3411 {
3416 tf_warning_or_error);
3417 }
3419 /* Conversion of conversion function return value failed. */
3422 else
3425 }
3427 /* Print information about a candidate with WANT parameters and we found
3428 HAVE. */
3430 static void
3432 {
3437 }
3439 /* Print information about one overload candidate CANDIDATE. MSGSTR
3440 is the text to print before the candidate itself.
3442 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3443 to have been run through gettext by the caller. This wart makes
3444 life simpler in print_z_candidates and for the translators. */
3446 static void
3449 {
3459 {
3470 else
3473 }
3480 else
3483 {
3486 }
3487 /* Give the user some information about why this candidate failed. */
3489 {
3493 {
3506 "cannot be converted to %qT with a qualification "
3512 "conversion function specialization to %qT is not an "
3517 /* We use template_unification_error_rejection if unification caused
3518 actual non-SFINAE errors, in which case we don't need to repeat
3519 them here. */
3521 {
3525 }
3526 /* Re-run template unification with diagnostics. */
3530 (make_tree_vec
3541 " a constructor taking a single argument of its own "
3545 {
3549 }
3553 "initialization from an expression of the same or derived "
3558 /* This candidate didn't have any issues or we failed to
3559 handle a particular code. Either way... */
3561 }
3562 }
3563 }
3565 static void
3567 {
3574 /* Remove non-viable deleted candidates. */
3577 {
3582 else
3584 }
3585 /* ...if there are any non-deleted ones. */
3589 /* There may be duplicates in the set of candidates. We put off
3590 checking this condition as long as possible, since we have no way
3591 to eliminate duplicates from a set of functions in less than n^2
3592 time. Now we are about to emit an error message, so it is more
3593 permissible to go slowly. */
3595 {
3597 /* Skip builtin candidates and conversion functions. */
3602 {
3606 else
3608 }
3609 }
3613 }
3615 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3616 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3617 the result of the conversion function to convert it to the final
3618 desired type. Merge the two sequences into a single sequence,
3619 and return the merged sequence. */
3623 {
3629 /* Find the end of the second conversion sequence. */
3631 {
3632 /* The entire sequence is a user-conversion sequence. */
3636 }
3638 /* Replace the identity conversion with the user conversion
3639 sequence. */
3643 }
3645 /* Handle overload resolution for initializing an object of class type from
3646 an initializer list. First we look for a suitable constructor that
3647 takes a std::initializer_list; if we don't find one, we then look for a
3648 non-list constructor.
3650 Parameters are as for add_candidates, except that the arguments are in
3651 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3652 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3654 static void
3661 tsubst_flags_t complain)
3662 {
3665 /* We're looking for a ctor for list-initialization. */
3667 /* And we don't allow narrowing conversions. We also use this flag to
3668 avoid the copy constructor call for copy-list-initialization. */
3674 /* Always use the default constructor if the list is empty (DR 990). */
3677 ;
3678 /* If the class has a list ctor, try passing the list as a single
3679 argument first, but only consider list ctors. */
3681 {
3688 }
3690 /* Expand the CONSTRUCTOR into a new argument vec. */
3698 /* We aren't looking for list-ctors anymore. */
3700 /* We allow more user-defined conversions within an init-list. */
3706 }
3708 /* Returns the best overload candidate to perform the requested
3709 conversion. This function is used for three the overloading situations
3710 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3711 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3712 per [dcl.init.ref], so we ignore temporary bindings. */
3716 tsubst_flags_t complain)
3717 {
3719 tree fromtype;
3733 /* We represent conversion within a hierarchy using RVALUE_CONV and
3734 BASE_CONV, as specified by [over.best.ics]; these become plain
3735 constructor calls, as specified in [dcl.init]. */
3740 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3741 creating a garbage BASELINK; constructors can't be inherited. */
3744 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3745 a single element. For now, let's handle constructors as before and also
3746 consider conversion operators from the element. */
3753 {
3758 {
3759 /* [class.conv.fct] A conversion function is never used to
3760 convert a (possibly cv-qualified) object to the (possibly
3761 cv-qualified) same object type (or a reference to it), to a
3762 (possibly cv-qualified) base class of that type (or a
3763 reference to it)... */
3764 }
3765 else
3767 }
3774 /* It's OK to bind a temporary for converting constructor arguments, but
3775 not in converting the return value of a conversion operator. */
3781 {
3786 /* We should never try to call the abstract or base constructor
3787 from here. */
3793 {
3794 /* List-initialization. */
3798 }
3799 else
3800 {
3804 }
3807 {
3810 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3811 set, then this is copy-initialization. In that case, "The
3812 result of the call is then used to direct-initialize the
3813 object that is the destination of the copy-initialization."
3814 [dcl.init]
3816 We represent this in the conversion sequence with an
3817 rvalue conversion, which means a constructor call. */
3820 cand->second_conv
3822 }
3823 }
3826 {
3828 /* FIXME see above about C++17. */
3830 else
3832 }
3835 {
3839 /* If we are called to convert to a reference type, we are trying to
3840 find a direct binding, so don't even consider temporaries. If
3841 we don't find a direct binding, the caller will try again to
3842 look for a temporary binding. */
3853 {
3855 conversion *ics
3857 rettype,
3860 complain);
3862 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3863 copy-initialization. In that case, "The result of the
3864 call is then used to direct-initialize the object that is
3865 the destination of the copy-initialization." [dcl.init]
3867 We represent this in the conversion sequence with an
3868 rvalue conversion, which means a constructor call. But
3869 don't add a second rvalue conversion if there's already
3870 one there. Which there really shouldn't be, but it's
3871 harmless since we'd add it here anyway. */
3879 {
3883 }
3886 {
3887 /* 13.3.1.5: For direct-initialization, those explicit
3888 conversion functions that are not hidden within S and
3889 yield type T or a type that can be converted to type T
3890 with a qualification conversion (4.4) are also candidate
3891 functions. */
3892 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3893 I've raised this issue with the committee. --jason 9/2011 */
3896 }
3898 {
3900 cand->reason
3903 }
3906 {
3907 /* 13.3.3.1.2: If the user-defined conversion is specified by
3908 a specialization of a conversion function template, the
3909 second standard conversion sequence shall have exact match
3910 rank. */
3913 }
3914 }
3915 }
3919 {
3923 }
3927 {
3929 {
3933 }
3940 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3941 ambiguous conversion is no worse than another user-defined
3942 conversion. */
3945 }
3947 tree convtype;
3951 /* DR 5: [in the first step of copy-initialization]...if the function
3952 is a constructor, the call initializes a temporary of the
3953 cv-unqualified version of the destination type. */
3955 else
3957 /* Build the user conversion sequence. */
3958 conv = build_conv
3960 convtype,
3966 /* Remember that this was a list-initialization. */
3970 /* Combine it with the second conversion sequence. */
3975 }
3977 /* Wrapper for above. */
3979 tree
3981 tsubst_flags_t complain)
3982 {
3984 tree ret;
3990 {
3993 else
3994 {
3997 }
3998 }
3999 else
4004 }
4006 /* Subroutine of convert_nontype_argument.
4008 EXPR is an argument for a template non-type parameter of integral or
4009 enumeration type. Do any necessary conversions (that are permitted for
4010 non-type arguments) to convert it to the parameter type.
4012 If conversion is successful, returns the converted expression;
4013 otherwise, returns error_mark_node. */
4015 tree
4017 {
4020 tree t;
4028 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4035 /* for a non-type template-parameter of integral or
4036 enumeration type, integral promotions (4.5) and integral
4037 conversions (4.7) are applied. */
4038 /* It should be sufficient to check the outermost conversion step, since
4039 there are no qualification conversions to integer type. */
4042 {
4043 /* A conversion function is OK. If it isn't constexpr, we'll
4044 complain later that the argument isn't constant. */
4046 /* The lvalue-to-rvalue conversion is OK. */
4059 /* fall through. */
4064 }
4068 else
4071 /* Free all the conversions we allocated. */
4075 }
4077 /* Do any initial processing on the arguments to a function call. */
4081 {
4083 tree arg;
4086 {
4090 {
4094 }
4097 }
4099 }
4101 /* Perform overload resolution on FN, which is called with the ARGS.
4103 Return the candidate function selected by overload resolution, or
4104 NULL if the event that overload resolution failed. In the case
4105 that overload resolution fails, *CANDIDATES will be the set of
4106 candidates considered, and ANY_VIABLE_P will be set to true or
4107 false to indicate whether or not any of the candidates were
4108 viable.
4110 The ARGS should already have gone through RESOLVE_ARGS before this
4111 function is called. */
4118 {
4120 tree explicit_targs;
4131 /* Check FN. */
4138 {
4142 }
4144 /* Add the various candidate functions. */
4149 LOOKUP_NORMAL,
4155 else
4160 }
4162 /* Print an error message about being unable to build a call to FN with
4163 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4164 be located; CANDIDATES is a possibly empty list of such
4165 functions. */
4167 static void
4170 {
4173 {
4176 }
4185 else
4190 }
4192 /* Return an expression for a call to FN (a namespace-scope function,
4193 or a static member function) with the ARGS. This may change
4194 ARGS. */
4196 tree
4198 tsubst_flags_t complain)
4199 {
4203 tree result;
4206 {
4210 }
4215 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4219 complain);
4222 {
4224 {
4225 // If there is a single (non-viable) function candidate,
4226 // let the error be diagnosed by cp_build_function_call_vec.
4231 // Otherwise, emit notes for non-viable candidates.
4233 }
4235 }
4236 else
4237 {
4239 /* If fn is template_id_expr, the call has explicit template arguments
4240 (e.g. func<int>(5)), communicate this info to build_over_call
4241 through flags so that later we can use it to decide whether to warn
4242 about peculiar null pointer conversion. */
4244 {
4245 /* If overload resolution selects a specialization of a
4246 function concept for non-dependent template arguments,
4247 the expression is true if the constraints are satisfied
4248 and false otherwise.
4250 NOTE: This is an extension of Concepts Lite TS that
4251 allows constraints to be used in expressions. */
4253 {
4259 }
4262 }
4265 }
4267 /* Free all the conversions we allocated. */
4271 }
4273 /* Build a call to a global operator new. FNNAME is the name of the
4274 operator (either "operator new" or "operator new[]") and ARGS are
4275 the arguments provided. This may change ARGS. *SIZE points to the
4276 total number of bytes required by the allocation, and is updated if
4277 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4278 be used. If this function determines that no cookie should be
4279 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4280 is not NULL_TREE, it is evaluated before calculating the final
4281 array size, and if it fails, the array size is replaced with
4282 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4283 is non-NULL, it will be set, upon return, to the allocation
4284 function called. */
4286 tree
4291 {
4293 tree fns;
4300 /* Set to (size_t)-1 if the size check fails. */
4302 {
4308 }
4314 /* Based on:
4316 [expr.new]
4318 If this lookup fails to find the name, or if the allocated type
4319 is not a class type, the allocation function's name is looked
4320 up in the global scope.
4322 we disregard block-scope declarations of "operator new". */
4327 {
4332 /* If no aligned allocation function matches, try again without the
4333 alignment. */
4334 }
4336 /* Figure out what function is being called. */
4339 complain);
4341 /* If no suitable function could be found, issue an error message
4342 and give up. */
4344 {
4348 }
4350 /* If a cookie is required, add some extra space. Whether
4351 or not a cookie is required cannot be determined until
4352 after we know which function was called. */
4354 {
4356 tree arg_types;
4359 /* Skip the size_t parameter. */
4361 /* Check the remaining parameters (if any). */
4365 ptr_type_node))
4367 /* If we need a cookie, adjust the number of bytes allocated. */
4369 {
4370 /* Update the total size. */
4373 {
4374 /* Set to (size_t)-1 if the size check fails. */
4378 }
4379 /* Update the argument list to reflect the adjusted size. */
4381 }
4382 else
4384 }
4386 /* Tell our caller which function we decided to call. */
4390 /* Build the CALL_EXPR. */
4392 }
4394 /* Build a new call to operator(). This may change ARGS. */
4396 static tree
4398 {
4412 {
4414 /* It's no good looking for an overloaded operator() on a
4415 pointer-to-member-function. */
4419 }
4422 {
4426 }
4427 else
4431 {
4435 }
4437 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4441 {
4449 }
4454 {
4462 {
4469 add_template_conv_candidate
4473 else
4477 }
4478 }
4480 /* Be strict here because if we choose a bad conversion candidate, the
4481 errors we get won't mention the call context. */
4484 {
4486 {
4490 }
4492 }
4493 else
4494 {
4497 {
4499 {
4503 }
4505 }
4506 /* Since cand->fn will be a type, not a function, for a conversion
4507 function, we must be careful not to unconditionally look at
4508 DECL_NAME here. */
4512 else
4513 {
4517 else
4521 }
4522 }
4524 /* Free all the conversions we allocated. */
4528 }
4530 /* Wrapper for above. */
4532 tree
4534 {
4535 tree ret;
4540 }
4542 /* Called by op_error to prepare format strings suitable for the error
4543 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4544 and a suffix (controlled by NTYPES). */
4548 {
4558 else
4562 }
4564 static void
4567 {
4572 else
4576 {
4582 else
4594 else
4604 else
4615 else
4625 else
4630 else
4634 else
4639 }
4640 }
4642 /* Return the implicit conversion sequence that could be used to
4643 convert E1 to E2 in [expr.cond]. */
4647 {
4653 /* [expr.cond]
4655 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4656 implicitly converted (clause _conv_) to the type "lvalue reference to
4657 T2", subject to the constraint that in the conversion the
4658 reference must bind directly (_dcl.init.ref_) to an lvalue.
4660 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4661 implicitly converted to the type "rvalue reference to T2", subject to
4662 the constraint that the reference must bind directly. */
4664 {
4667 t1,
4668 e1,
4670 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4672 complain);
4675 }
4677 /* If E2 is a prvalue or if neither of the conversions above can be done
4678 and at least one of the operands has (possibly cv-qualified) class
4679 type: */
4683 /* [expr.cond]
4685 If E1 and E2 have class type, and the underlying class types are
4686 the same or one is a base class of the other: E1 can be converted
4687 to match E2 if the class of T2 is the same type as, or a base
4688 class of, the class of T1, and the cv-qualification of T2 is the
4689 same cv-qualification as, or a greater cv-qualification than, the
4690 cv-qualification of T1. If the conversion is applied, E1 is
4691 changed to an rvalue of type T2 that still refers to the original
4692 source class object (or the appropriate subobject thereof). */
4695 {
4697 {
4702 else
4705 }
4706 else
4708 }
4709 else
4710 /* [expr.cond]
4712 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4713 converted to the type that expression E2 would have if E2 were
4714 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4717 }
4719 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4720 arguments to the conditional expression. */
4722 static tree
4724 tsubst_flags_t complain)
4725 {
4726 tree arg2_type;
4727 tree arg3_type;
4736 /* As a G++ extension, the second argument to the conditional can be
4737 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4738 c'.) If the second operand is omitted, make sure it is
4739 calculated only once. */
4741 {
4749 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4752 else
4754 }
4756 /* If something has already gone wrong, just pass that fact up the
4757 tree. */
4767 {
4770 /* If arg1 is another cond_expr choosing between -1 and 0,
4771 then we can use its comparison. It may help to avoid
4772 additional comparison, produce more accurate diagnostics
4773 and enables folding. */
4783 /* force_rvalue can return error_mark on valid arguments. */
4794 {
4795 /* Rely on the error messages of the scalar version. */
4804 {
4812 }
4816 /* We could pass complain & tf_warning to unsafe_conversion_p,
4817 but the warnings (like Wsign-conversion) have already been
4818 given by the scalar build_conditional_expr_1. We still check
4819 unsafe_conversion_p to forbid truncating long long -> float. */
4821 {
4826 }
4828 {
4833 }
4843 }
4846 {
4852 {
4856 {
4862 }
4864 {
4870 }
4873 }
4874 }
4880 {
4883 "incompatible vector types in conditional expression: "
4887 }
4890 {
4893 }
4895 }
4897 /* [expr.cond]
4899 The first expression is implicitly converted to bool (clause
4900 _conv_). */
4902 LOOKUP_NORMAL);
4906 /* [expr.cond]
4908 If either the second or the third operand has type (possibly
4909 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4910 array-to-pointer (_conv.array_), and function-to-pointer
4911 (_conv.func_) standard conversions are performed on the second
4912 and third operands. */
4916 {
4917 /* Do the conversions. We don't these for `void' type arguments
4918 since it can't have any effect and since decay_conversion
4919 does not handle that case gracefully. */
4927 /* [expr.cond]
4929 One of the following shall hold:
4931 --The second or the third operand (but not both) is a
4932 throw-expression (_except.throw_); the result is of the
4933 type of the other and is an rvalue.
4935 --Both the second and the third operands have type void; the
4936 result is of type void and is an rvalue.
4938 We must avoid calling force_rvalue for expressions of type
4939 "void" because it will complain that their value is being
4940 used. */
4943 {
4945 {
4949 }
4952 }
4955 {
4957 {
4961 }
4964 }
4967 else
4968 {
4970 {
4973 "second operand to the conditional operator "
4974 "is of type %<void%>, but the third operand is "
4976 else
4978 "third operand to the conditional operator "
4979 "is of type %<void%>, but the second operand is "
4981 }
4983 }
4987 }
4988 /* [expr.cond]
4990 Otherwise, if the second and third operand have different types,
4991 and either has (possibly cv-qualified) class type, or if both are
4992 glvalues of the same value category and the same type except for
4993 cv-qualification, an attempt is made to convert each of those operands
4994 to the type of the other. */
4998 arg3_type)
5001 {
5006 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5012 /* [expr.cond]
5014 If both can be converted, or one can be converted but the
5015 conversion is ambiguous, the program is ill-formed. If
5016 neither can be converted, the operands are left unchanged and
5017 further checking is performed as described below. If exactly
5018 one conversion is possible, that conversion is applied to the
5019 chosen operand and the converted operand is used in place of
5020 the original operand for the remainder of this section. */
5025 {
5027 {
5034 else
5036 }
5038 }
5040 {
5044 /* Even if CONV2 is a valid conversion, the result of the
5045 conversion may be invalid. For example, if ARG3 has type
5046 "volatile X", and X does not have a copy constructor
5047 accepting a "volatile X&", then even if ARG2 can be
5048 converted to X, the conversion will fail. */
5052 }
5054 {
5061 }
5063 /* Free all the conversions we allocated. */
5069 /* If, after the conversion, both operands have class type,
5070 treat the cv-qualification of both operands as if it were the
5071 union of the cv-qualification of the operands.
5073 The standard is not clear about what to do in this
5074 circumstance. For example, if the first operand has type
5075 "const X" and the second operand has a user-defined
5076 conversion to "volatile X", what is the type of the second
5077 operand after this step? Making it be "const X" (matching
5078 the first operand) seems wrong, as that discards the
5079 qualification without actually performing a copy. Leaving it
5080 as "volatile X" seems wrong as that will result in the
5081 conditional expression failing altogether, even though,
5082 according to this step, the one operand could be converted to
5083 the type of the other. */
5091 }
5093 /* [expr.cond]
5095 If the second and third operands are glvalues of the same value
5096 category and have the same type, the result is of that type and
5097 value category. */
5101 {
5106 }
5108 /* [expr.cond]
5110 Otherwise, the result is an rvalue. If the second and third
5111 operand do not have the same type, and either has (possibly
5112 cv-qualified) class type, overload resolution is used to
5113 determine the conversions (if any) to be applied to the operands
5114 (_over.match.oper_, _over.built_). */
5118 {
5123 /* Rearrange the arguments so that add_builtin_candidate only has
5124 to know about two args. In build_builtin_candidate, the
5125 arguments are unscrambled. */
5130 COND_EXPR,
5131 NOP_EXPR,
5133 args,
5136 /* [expr.cond]
5138 If the overload resolution fails, the program is
5139 ill-formed. */
5142 {
5147 }
5150 {
5152 {
5155 }
5157 }
5159 /* [expr.cond]
5161 Otherwise, the conversions thus determined are applied, and
5162 the converted operands are used in place of the original
5163 operands for the remainder of this section. */
5172 }
5174 /* [expr.cond]
5176 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5177 and function-to-pointer (_conv.func_) standard conversions are
5178 performed on the second and third operands.
5180 We need to force the lvalue-to-rvalue conversion here for class types,
5181 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5182 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5183 regions. */
5196 /* [expr.cond]
5198 After those conversions, one of the following shall hold:
5200 --The second and third operands have the same type; the result is of
5201 that type. */
5204 /* [expr.cond]
5206 --The second and third operands have arithmetic or enumeration
5207 type; the usual arithmetic conversions are performed to bring
5208 them to a common type, and the result is of that type. */
5213 {
5214 /* In this case, there is always a common type. */
5216 arg3_type);
5219 "implicit conversion from %qH to %qI to "
5221 loc);
5225 {
5229 /* Two enumerators from the same enumeration can have different
5235 }
5242 {
5246 }
5250 }
5251 /* [expr.cond]
5253 --The second and third operands have pointer type, or one has
5254 pointer type and the other is a null pointer constant; pointer
5255 conversions (_conv.ptr_) and qualification conversions
5256 (_conv.qual_) are performed to bring them to their composite
5257 pointer type (_expr.rel_). The result is of the composite
5258 pointer type.
5260 --The second and third operands have pointer to member type, or
5261 one has pointer to member type and the other is a null pointer
5262 constant; pointer to member conversions (_conv.mem_) and
5263 qualification conversions (_conv.qual_) are performed to bring
5264 them to a common type, whose cv-qualification shall match the
5265 cv-qualification of either the second or the third operand.
5266 The result is of the common type. */
5274 {
5277 complain);
5282 }
5285 {
5290 }
5295 valid_operands:
5298 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5299 warn here, because the COND_EXPR will be turned into ARG2. */
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;
5385 /* Precalculate special handling of constructors and conversion ops. */
5388 {
5392 /* We're doing return_type(x). */
5394 else
5395 /* We're doing x.operator return_type(). */
5397 /* [over.match.funcs] For conversion functions, the function
5398 is considered to be a member of the class of the implicit
5399 object argument for the purpose of defining the type of
5400 the implicit object parameter. */
5402 }
5403 else
5404 {
5406 {
5408 /* For list-initialization we consider explicit constructors
5409 and complain if one is chosen. */
5410 check_converting
5413 }
5414 else
5415 {
5418 }
5421 }
5425 else
5426 /* Delay creating the implicit this parameter until it is needed. */
5430 {
5431 tree fn_first_arg;
5441 /* Figure out which set of arguments to use. */
5443 {
5444 /* If this function is a non-static member and we didn't get an
5445 implicit object argument, move it out of args. */
5447 {
5449 tree arg;
5456 }
5460 }
5461 else
5462 {
5463 /* Otherwise, just use the list of arguments provided. */
5466 }
5470 fn,
5471 ctype,
5472 explicit_targs,
5473 fn_first_arg,
5474 fn_args,
5475 return_type,
5476 access_path,
5477 conversion_path,
5478 flags,
5479 strict,
5480 complain);
5483 fn,
5484 ctype,
5485 fn_first_arg,
5486 fn_args,
5487 access_path,
5488 conversion_path,
5489 flags,
5490 complain);
5491 }
5492 }
5494 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5495 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5497 static int
5499 {
5501 {
5502 // 5. b @= a
5506 // 6. a[b]
5510 // 1. a.b
5511 // Not overloadable (yet).
5512 // 2. a->b
5513 // Only one argument.
5514 // 3. a->*b
5516 // 7. a << b
5518 // 8. a >> b
5524 }
5525 }
5527 static tree
5530 {
5533 tree fnname;
5551 {
5555 }
5556 else
5563 {
5568 /* Use build_op_new_call and build_op_delete_call instead. */
5572 /* Use build_op_call instead. */
5579 /* These are saved for the sake of warn_logical_operator. */
5589 /* These are saved for the sake of maybe_warn_bool_compare. */
5594 /* =, ->, [], () must be non-static member functions. */
5598 /* FALLTHRU */
5606 }
5612 /* Use build_conditional_expr instead. */
5628 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5631 /* Add namespace-scope operators to the list of functions to
5632 consider. */
5634 {
5640 }
5646 /* Add class-member operators to the candidate set. */
5648 {
5649 tree fns;
5653 {
5656 }
5664 }
5665 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5666 only non-member functions that have type T1 or reference to
5667 cv-qualified-opt T1 for the first argument, if the first argument
5668 has an enumeration type, or T2 or reference to cv-qualified-opt
5669 T2 for the second argument, if the second argument has an
5670 enumeration type. Filter out those that don't match. */
5672 {
5676 {
5686 {
5692 && (same_type_ignoring_top_level_qualifiers_p
5697 }
5699 /* No argument has an appropriate type, so remove this
5700 candidate function from the list. */
5702 {
5705 }
5706 }
5707 }
5713 {
5716 /* For these, the built-in candidates set is empty
5717 [over.match.oper]/3. We don't want non-strict matches
5718 because exact matches are always possible with built-in
5719 operators. The built-in candidate set for COMPONENT_REF
5720 would be empty too, but since there are no such built-in
5721 operators, we accept non-strict matches for them. */
5728 }
5732 {
5734 {
5737 /* Don't try anything fancy if we're not allowed to produce
5738 errors. */
5742 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5743 distinguish between prefix and postfix ++ and
5744 operator++() was used for both, so we allow this with
5745 -fpermissive. */
5746 else
5747 {
5753 }
5760 else
5766 /* The caller will deal with these. */
5776 {
5777 /* If one of the arguments of the operator represents
5778 an invalid use of member function pointer, try to report
5779 a meaningful error ... */
5784 else
5785 {
5786 /* ... Otherwise, report the more generic
5787 "no matching operator found" error */
5790 }
5791 }
5794 }
5795 }
5796 else
5797 {
5800 {
5802 {
5805 }
5807 }
5809 {
5815 else
5821 {
5826 /* This prevents build_new_function_call from discarding this
5827 function during instantiation of the enclosing template. */
5830 /* Specify evaluation order as per P0145R2. */
5833 {
5844 }
5845 }
5846 }
5847 else
5848 {
5849 /* Give any warnings we noticed during overload resolution. */
5851 {
5855 }
5857 /* Check for comparison of different enum types. */
5859 {
5871 {
5875 }
5879 }
5881 /* We need to strip any leading REF_BIND so that bitfields
5882 don't cause errors. This should not remove any important
5883 conversions, because builtins don't apply to class
5884 objects directly. */
5891 {
5895 else
5898 /* We need to call warn_logical_operator before
5899 converting arg2 to a boolean_type, but after
5900 decaying an enumerator to its value. */
5907 }
5909 {
5914 }
5916 }
5917 }
5919 user_defined_result_ready:
5921 /* Free all the conversions we allocated. */
5927 builtin:
5929 {
5944 /* Fall through. */
5957 /* Fall through. */
5990 complain),
5993 /* The caller will deal with these. */
6001 }
6003 }
6005 /* Wrapper for above. */
6007 tree
6011 {
6012 tree ret;
6018 }
6020 /* CALL was returned by some call-building function; extract the actual
6021 CALL_EXPR from any bits that have been tacked on, e.g. by
6022 convert_from_reference. */
6024 tree
6026 {
6037 }
6039 /* Returns true if FN has two parameters, of which the second has type
6040 size_t. */
6042 static bool
6044 {
6056 }
6058 /* True if T, an allocation function, has std::align_val_t as its second
6059 argument. */
6061 bool
6063 {
6069 }
6071 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6072 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6073 std::align_val_t. */
6075 static bool
6077 {
6081 /* A template instance is never a usual deallocation function,
6082 regardless of its signature. */
6098 }
6100 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6101 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6103 bool
6105 {
6106 /* A template instance is never a usual deallocation function,
6107 regardless of its signature. */
6112 /* If a class T has a member deallocation function named operator delete
6113 with exactly one parameter, then that function is a usual
6114 (non-placement) deallocation function. If class T does not declare
6115 such an operator delete but does declare a member deallocation
6116 function named operator delete with exactly two parameters, the second
6117 of which has type std::size_t (18.2), then this function is a usual
6118 deallocation function. */
6130 }
6132 /* Build a call to operator delete. This has to be handled very specially,
6133 because the restrictions on what signatures match are different from all
6134 other call instances. For a normal delete, only a delete taking (void *)
6135 or (void *, size_t) is accepted. For a placement delete, only an exact
6136 match with the placement new is accepted.
6138 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6139 ADDR is the pointer to be deleted.
6140 SIZE is the size of the memory block to be deleted.
6141 GLOBAL_P is true if the delete-expression should not consider
6142 class-specific delete operators.
6143 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6145 If this call to "operator delete" is being generated as part to
6146 deallocate memory allocated via a new-expression (as per [expr.new]
6147 which requires that if the initialization throws an exception then
6148 we call a deallocation function), then ALLOC_FN is the allocation
6149 function. */
6151 tree
6155 {
6169 /* In [class.free]
6171 If the result of the lookup is ambiguous or inaccessible, or if
6172 the lookup selects a placement deallocation function, the
6173 program is ill-formed.
6175 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6176 {
6180 }
6181 else
6187 /* Strip const and volatile from addr. */
6191 {
6192 /* "A declaration of a placement deallocation function matches the
6193 declaration of a placement allocation function if it has the same
6194 number of parameters and, after parameter transformations (8.3.5),
6195 all parameter types except the first are identical."
6197 So we build up the function type we want and ask instantiate_type
6198 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." */
6269 {
6272 {
6274 {
6277 }
6279 /* -- If the type has new-extended alignment, a function with a
6280 parameter of type std::align_val_t is preferred; otherwise a
6281 function without such a parameter is preferred. If exactly one
6282 preferred function is found, that function is selected and the
6283 selection process terminates. If more than one preferred
6284 function is found, all non-preferred functions are eliminated
6285 from further consideration. */
6287 {
6293 {
6297 }
6298 }
6300 /* -- If the deallocation functions have class scope, the one
6301 without a parameter of type std::size_t is selected. */
6306 /* -- If the type is complete and if, for the second alternative
6307 (delete array) only, the operand is a pointer to a class type
6308 with a non-trivial destructor or a (possibly multi-dimensional)
6309 array thereof, the function with a parameter of type std::size_t
6310 is selected.
6312 -- Otherwise, it is unspecified whether a deallocation function
6313 with a parameter of type std::size_t is selected. */
6314 else
6315 {
6319 /* We need a cookie to determine the array size. */
6321 }
6327 }
6328 }
6330 /* If we have a matching function, call it. */
6332 {
6335 /* If the FN is a member function, make sure that it is
6336 accessible. */
6339 complain);
6341 /* Core issue 901: It's ok to new a type with deleted delete. */
6346 {
6347 /* The placement args might not be suitable for overload
6348 resolution at this point, so build the call directly. */
6358 }
6359 else
6360 {
6361 tree ret;
6367 {
6370 }
6374 }
6375 }
6377 /* [expr.new]
6379 If no unambiguous matching deallocation function can be found,
6380 propagating the exception does not cause the object's memory to
6381 be freed. */
6383 {
6387 alloc_fn);
6389 }
6395 }
6397 /* If the current scope isn't allowed to access DECL along
6398 BASETYPE_PATH, give an error. The most derived class in
6399 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6400 the declaration to use in the error diagnostic. */
6402 bool
6405 {
6410 {
6411 /* 7.3.3/18: The additional constructors are accessible if they would be
6412 accessible when used to construct an object of the corresponding base
6413 class. */
6417 }
6420 {
6422 {
6426 {
6432 }
6434 {
6440 }
6441 else
6442 {
6447 }
6448 }
6450 }
6453 }
6455 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6456 bitwise or of LOOKUP_* values. If any errors are warnings are
6457 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6458 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6459 to NULL. */
6461 static tree
6464 {
6470 /* If the source is a packed field, calling the copy constructor will require
6471 binding the field to the reference parameter to the copy constructor, and
6472 we'll end up with an infinite loop. If we can use a bitwise copy, then
6473 do that now. */
6489 }
6491 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6492 EXPR is implicitly converted to type TOTYPE.
6493 FN and ARGNUM are used for diagnostics. */
6495 static void
6497 {
6498 /* Issue warnings about peculiar, but valid, uses of NULL. */
6501 {
6502 source_location loc =
6509 else
6512 }
6514 /* Issue warnings if "false" is converted to a NULL pointer */
6517 {
6520 "converting %<false%> to pointer type for argument %P "
6522 else
6525 }
6526 }
6528 /* We gave a diagnostic during a conversion. If this was in the second
6529 standard conversion sequence of a user-defined conversion sequence, say
6530 which user-defined conversion. */
6532 static void
6534 {
6538 {
6542 }
6543 }
6545 /* Perform the conversions in CONVS on the expression EXPR. FN and
6546 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6547 indicates the `this' argument of a method. INNER is nonzero when
6548 being called to continue a conversion chain. It is negative when a
6549 reference binding will be applied, positive otherwise. If
6550 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6551 conversions will be emitted if appropriate. If C_CAST_P is true,
6552 this conversion is coming from a C-style cast; in that case,
6553 conversions to inaccessible bases are permitted. */
6555 static tree
6559 {
6561 diagnostic_t diag_kind;
6577 {
6581 /* Give a helpful error if this is bad because of excess braces. */
6586 {
6592 }
6594 /* Give a helpful error if this is bad because a conversion to bool
6595 from std::nullptr_t requires direct-initialization. */
6603 {
6605 {
6608 totype);
6614 complain);
6618 complain);
6619 else
6625 }
6627 {
6631 complain);
6633 }
6638 complain);
6641 }
6650 }
6656 {
6658 {
6662 /* When converting from an init list we consider explicit
6663 constructors, but actually trying to call one is an error. */
6666 /* Unless this is for direct-list-initialization. */
6668 /* And in C++98 a default constructor can't be explicit. */
6670 {
6676 {
6682 }
6683 else
6686 }
6688 /* If we're initializing from {}, it's value-initialization. */
6692 {
6697 {
6700 }
6702 }
6706 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6707 any more UDCs. */
6709 complain);
6711 /* If this is a constructor or a function returning an aggr type,
6712 we need to build up a TARGET_EXPR. */
6714 {
6717 /* Remember that this was list-initialization. */
6720 }
6723 }
6726 {
6732 else
6734 }
6741 /* We leave bad_p off ck_ambig because overload resolution considers
6742 it valid, it just fails when we try to perform it. So we need to
6743 check complain here, too. */
6745 {
6746 /* Call build_user_type_conversion again for the error. */
6748 complain);
6752 }
6756 {
6757 /* Conversion to std::initializer_list<T>. */
6765 /* Convert all the elements. */
6767 {
6778 }
6779 /* Build up the array. */
6780 elttype = cp_build_qualified_type
6784 /* Take the address explicitly rather than via decay_conversion
6785 to avoid the error about taking the address of a temporary. */
6791 /* Build up the initializer_list object. */
6799 }
6803 {
6812 }
6815 complain);
6822 };
6826 c_cast_p,
6827 complain);
6832 {
6836 {
6838 {
6843 }
6845 }
6850 /* Don't introduce copies when passing arguments along to the inherited
6851 constructor. */
6853 && flag_new_inheriting_ctors
6857 /* Fall through. */
6860 {
6861 /* We are going to bind a reference directly to a base-class
6862 subobject of EXPR. */
6863 /* Build an expression for `*((base*) &expr)'. */
6867 }
6869 /* Copy-initialization where the cv-unqualified version of the source
6870 type is the same class as, or a derived class of, the class of the
6871 destination [is treated as direct-initialization]. [dcl.init] */
6874 /* This conversion is being done in the context of a user-defined
6875 conversion (i.e. the second step of copy-initialization), so
6876 don't allow any more. */
6878 else
6884 /* Copy-list-initialization doesn't actually involve a copy. */
6888 {
6893 }
6898 {
6902 {
6915 else
6922 }
6924 /* If necessary, create a temporary.
6926 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6927 that need temporaries, even when their types are reference
6928 compatible with the type of reference being bound, so the
6929 upcoming call to cp_build_addr_expr doesn't fail. */
6933 {
6934 /* Otherwise, a temporary of type "cv1 T1" is created and
6935 initialized from the initializer expression using the rules
6936 for a non-reference copy-initialization (8.5). */
6945 {
6946 /* If the reference is volatile or non-const, we
6947 cannot create a temporary. */
6954 else
6958 }
6959 /* If the source is a packed field, and we must use a copy
6960 constructor, then building the target expr will require
6961 binding the field to the reference parameter to the
6962 copy constructor, and we'll end up with an infinite
6963 loop. If we can use a bitwise copy, then we'll be
6964 OK. */
6968 {
6972 }
6974 {
6977 }
6979 }
6981 /* Take the address of the thing to which we will bind the
6982 reference. */
6987 /* Convert it to a pointer to the type referred to by the
6988 reference. This will adjust the pointer if a derived to
6989 base conversion is being performed. */
6992 /* Convert the pointer to the desired reference type. */
6994 }
7000 /* ??? Should the address of a transaction-safe pointer point to the TM
7001 clone, and this conversion look up the primary function? */
7005 /* Warn about deprecated conversion if appropriate. */
7021 }
7029 else
7033 }
7035 /* ARG is being passed to a varargs function. Perform any conversions
7036 required. Return the converted value. */
7038 tree
7040 {
7041 tree arg_type;
7044 /* [expr.call]
7046 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7047 standard conversions are performed. */
7050 /* [expr.call]
7052 If the argument has integral or enumeration type that is subject
7053 to the integral promotions (_conv.prom_), or a floating point
7054 type that is subject to the floating point promotion
7055 (_conv.fpprom_), the value of the argument is converted to the
7056 promoted type before the call. */
7061 {
7065 "implicit conversion from %qH to %qI when passing "
7069 }
7073 {
7075 {
7077 complain);
7087 }
7088 else
7090 }
7096 /* In a template (or ill-formed code), we can have an incomplete type
7097 even after require_complete_type_sfinae, in which case we don't know
7098 whether it has trivial copy or not. */
7100 {
7101 /* Build up a real lvalue-to-rvalue conversion in case the
7102 copy constructor is trivial but not callable. */
7106 /* [expr.call] 5.2.2/7:
7107 Passing a potentially-evaluated argument of class type (Clause 9)
7108 with a non-trivial copy constructor or a non-trivial destructor
7109 with no corresponding parameter is conditionally-supported, with
7110 implementation-defined semantics.
7112 We support it as pass-by-invisible-reference, just like a normal
7113 value parameter.
7115 If the call appears in the context of a sizeof expression,
7116 it is not potentially-evaluated. */
7120 {
7123 "passing objects of non-trivially-copyable "
7125 arg_type);
7127 }
7128 }
7131 }
7133 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7135 tree
7137 {
7139 {
7143 }
7153 {
7156 }
7160 {
7161 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7162 it as pass by invisible reference. */
7164 "receiving objects of non-trivially-copyable type %q#T "
7170 }
7174 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7175 know how to handle it. */
7178 }
7180 /* TYPE has been given to va_arg. Apply the default conversions which
7181 would have happened when passed via ellipsis. Return the promoted
7182 type, or the passed type if there is no change. */
7184 tree
7186 {
7187 tree promote;
7189 /* Perform the array-to-pointer and function-to-pointer
7190 conversions. */
7198 }
7200 /* ARG is a default argument expression being passed to a parameter of
7201 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7202 zero-based argument number. Do any required conversions. Return
7203 the converted value. */
7206 void
7210 void
7214 tree
7216 tsubst_flags_t complain)
7217 {
7219 tree t;
7221 /* See through clones. */
7223 /* And inheriting ctors. */
7227 /* Detect recursion. */
7230 {
7234 }
7236 /* If the ARG is an unparsed default argument expression, the
7237 conversion cannot be performed. */
7239 {
7244 }
7251 /* Due to:
7253 [dcl.fct.default]
7255 The names in the expression are bound, and the semantic
7256 constraints are checked, at the point where the default
7257 expressions appears.
7259 we must not perform access checks here. */
7261 /* We must make a copy of ARG, in case subsequent processing
7262 alters any part of it. */
7266 complain);
7273 }
7275 /* Returns the type which will really be used for passing an argument of
7276 type TYPE. */
7278 tree
7280 {
7281 /* Pass classes with copy ctors by invisible reference. */
7283 {
7285 /* There are no other pointers to this temporary. */
7287 }
7295 }
7297 /* Actually perform the appropriate conversion. */
7299 tree
7301 {
7302 tree bitfield_type;
7304 /* If VAL is a bitfield, then -- since it has already been converted
7305 to TYPE -- it cannot have a precision greater than TYPE.
7307 If it has a smaller precision, we must widen it here. For
7308 example, passing "int f:3;" to a function expecting an "int" will
7309 not result in any conversion before this point.
7311 If the precision is the same we must not risk widening. For
7312 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7313 often have type "int", even though the C++ type for the field is
7314 "long long". If the value is being passed to a function
7315 expecting an "int", then no conversions will be required. But,
7316 if we call convert_bitfield_to_declared_type, the bitfield will
7317 be converted to "long long". */
7324 ;
7325 /* Pass classes with copy ctors by invisible reference. */
7334 {
7336 {
7344 "argument of function call might be a candidate "
7346 }
7348 }
7350 }
7352 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7353 which just decay_conversion or no conversions at all should be done.
7354 This is true for some builtins which don't act like normal functions.
7355 Return 2 if no conversions at all should be done, 1 if just
7356 decay_conversion. Return 3 for special treatment of the 3rd argument
7357 for __builtin_*_overflow_p. */
7359 int
7361 {
7367 {
7382 }
7385 }
7387 /* Returns the decl of the dispatcher function if FN is a function version. */
7389 tree
7391 {
7401 {
7405 }
7410 }
7412 /* fn is a function version dispatcher that is marked used. Mark all the
7413 semantically identical function versions it will dispatch as used. */
7415 void
7417 {
7434 /* All semantically identical versions are chained. Traverse and mark each
7435 one of them as used. */
7438 {
7441 }
7442 }
7444 /* Build a call to "the copy constructor" for the type of A, even if it
7445 wouldn't be selected by normal overload resolution. Used for
7446 diagnostics. */
7448 static tree
7450 {
7461 }
7463 /* Return true iff T refers to a base field. */
7465 static bool
7467 {
7476 }
7478 /* We can't elide a copy from a function returning by value to a base
7479 subobject, as the callee might clobber tail padding. Return true iff this
7480 could be that case. */
7482 static bool
7484 {
7485 /* Copy elision only happens with a TARGET_EXPR. */
7489 /* It's safe to elide the copy for a class with no tail padding. */
7492 /* It's safe to elide the copy if we aren't initializing a base object. */
7496 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7501 }
7503 /* Subroutine of the various build_*_call functions. Overload resolution
7504 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7505 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7506 bitmask of various LOOKUP_* flags which apply to the call itself. */
7508 static tree
7510 {
7518 tree val;
7527 /* In a template, there is no need to perform all of the work that
7528 is normally done. We are only interested in the type of the call
7529 expression, i.e., the return type of the function. Any semantic
7530 errors will be deferred until the template is instantiated. */
7532 {
7534 tree return_type;
7542 else
7543 {
7546 tree arg;
7554 }
7564 }
7566 /* Give any warnings we noticed during overload resolution. */
7568 {
7572 }
7574 /* OK, we're actually calling this inherited constructor; set its deletedness
7575 appropriately. We can get away with doing this here because calling is
7576 the only way to refer to a constructor. */
7580 /* Make =delete work with SFINAE. */
7585 {
7586 tree access_fn;
7587 /* If FN is a template function, two cases must be considered.
7588 For example:
7590 struct A {
7591 protected:
7592 template <class T> void f();
7593 };
7594 template <class T> struct B {
7595 protected:
7596 void g();
7597 };
7598 struct C : A, B<int> {
7599 using A::f; // #1
7600 using B<int>::g; // #2
7601 };
7603 In case #1 where `A::f' is a member template, DECL_ACCESS is
7604 recorded in the primary template but not in its specialization.
7605 We check access of FN using its primary template.
7607 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7608 because it is a member of class template B, DECL_ACCESS is
7609 recorded in the specialization `B<int>::g'. We cannot use its
7610 primary template because `B<T>::g' and `B<int>::g' may have
7611 different access. */
7615 else
7620 }
7622 /* If we're checking for implicit delete, don't bother with argument
7623 conversions. */
7625 {
7627 {
7631 }
7635 /* Reject bad conversions now. */
7637 /* else continue to get conversion error. */
7638 }
7640 /* N3276 magic doesn't apply to nested calls. */
7644 /* Find maximum size of vector to hold converted arguments. */
7651 /* The implicit parameters to a constructor are not considered by overload
7652 resolution, and must be of the proper type. */
7654 {
7655 tree object_arg;
7657 {
7660 }
7661 else
7662 {
7665 }
7668 /* We should never try to call the abstract constructor. */
7672 {
7676 }
7677 }
7678 /* Bypass access control for 'this' parameter. */
7680 {
7683 ? first_arg
7686 tree converted_arg;
7687 tree base_binfo;
7690 {
7692 {
7697 }
7698 else
7700 }
7702 /* See if the function member or the whole class type is declared
7703 final and the call can be devirtualized. */
7708 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7709 X is called for an object that is not of type X, or of a type
7710 derived from X, the behavior is undefined.
7712 So we can assume that anything passed as 'this' is non-null, and
7713 optimize accordingly. */
7715 /* Convert to the base in which the function was declared. */
7718 arg,
7721 /* Check that the base class is accessible. */
7724 {
7729 else
7731 }
7732 /* If fn was found by a using declaration, the conversion path
7733 will be to the derived class, not the base declaring fn. We
7734 must convert from derived to base. */
7745 else
7749 }
7754 {
7761 /* If the argument is NULL and used to (implicitly) instantiate a
7762 template function (and bind one of the template arguments to
7763 the type of 'long int'), we don't want to warn about passing NULL
7764 to non-pointer argument.
7765 For example, if we have this template function:
7767 template<typename T> void func(T x) {}
7769 we want to warn (when -Wconversion is enabled) in this case:
7771 void foo() {
7772 func<int>(NULL);
7773 }
7775 but not in this case:
7777 void foo() {
7778 func(NULL);
7779 }
7780 */
7787 /* Warn about initializer_list deduction that isn't currently in the
7788 working draft. */
7790 && flag_deduce_init_list
7794 {
7807 {
7815 }
7816 }
7818 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7819 knows not to allow any more UDCs. This needs to happen after we
7820 process cand->warnings. */
7829 arg_complain);
7834 else
7836 }
7838 /* Default arguments */
7840 {
7846 complain);
7847 }
7849 /* Ellipsis */
7852 {
7855 {
7856 /* Do no conversions for certain magic varargs. */
7860 }
7862 /* For other magic varargs only do decay_conversion. */
7867 {
7868 /* Avoid infinite recursion trying to call A(...). */
7870 /* Try to call the actual copy constructor for a good error. */
7873 }
7874 else
7879 }
7884 /* Avoid to do argument-transformation, if warnings for format, and for
7885 nonnull are disabled. Just in case that at least one of them is active
7886 the check_function_arguments function might warn about something. */
7890 || warn_format
7891 || warn_suggest_attribute_format
7893 {
7901 }
7904 {
7905 /* Check for passing ellipsis arguments to an inherited constructor. We
7906 could handle this by open-coding the inherited constructor rather than
7907 defining it, but let's not bother now. */
7911 {
7913 {
7917 }
7919 }
7921 /* A base constructor inheriting from a virtual base doesn't get the
7922 inherited arguments, just this and __vtt. */
7925 }
7927 /* Avoid actually calling copy constructors and copy assignment operators,
7928 if possible. */
7935 /* It's unsafe to elide the constructor when handling
7936 a noexcept-expression, it may evaluate to the wrong
7937 value (c++/53025). */
7939 {
7940 tree targ;
7942 tree fa;
7945 /* Pull out the real argument, disregarding const-correctness. */
7947 /* Strip the reference binding for the constructor parameter. */
7951 /* But don't strip any other reference bindings; binding a temporary to a
7952 reference prevents copy elision. */
7958 {
7963 }
7964 else
7969 else
7972 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
7973 subobject. */
7977 /* See unsafe_copy_elision_p. */
7980 /* [class.copy]: the copy constructor is implicitly defined even if
7981 the implementation elided its use. */
7983 {
7987 }
7989 /* If we're creating a temp and we already have one, don't create a
7990 new one. If we're not creating a temp but we get one, use
7991 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7992 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7993 temp or an INIT_EXPR otherwise. */
7996 {
8001 }
8004 {
8006 RO_NULL,
8007 complain));
8011 }
8012 }
8016 {
8017 tree to = cp_stabilize_reference
8024 {
8025 /* Avoid copying empty classes. */
8028 }
8030 {
8033 /* Handle NSDMI that refer to the object being initialized. */
8035 }
8036 else
8037 {
8038 /* We must only copy the non-tail padding parts. */
8046 build_index_type
8055 }
8058 }
8061 {
8065 {
8068 else
8070 }
8071 }
8073 /* For calls to a multi-versioned function, overload resolution
8074 returns the function with the highest target priority, that is,
8075 the version that will checked for dispatching first. If this
8076 version is inlinable, a direct call to this version can be made
8077 otherwise the call should go through the dispatcher. */
8082 {
8088 }
8095 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8096 virtual functions can't be constexpr. */
8098 {
8099 tree t;
8106 complain);
8112 }
8113 else
8114 {
8118 }
8124 {
8126 /* build_new_op_1 will clear this when appropriate. */
8128 }
8130 {
8134 }
8136 }
8138 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8139 This function performs no overload resolution, conversion, or other
8140 high-level operations. */
8142 tree
8144 tsubst_flags_t complain)
8145 {
8146 tree fndecl;
8148 /* Remember roughly where this call is. */
8155 /* Check that arguments to builtin functions match the expectations. */
8159 {
8162 /* We need to take care that values to BUILT_IN_NORMAL
8163 are reduced. */
8170 }
8172 /* If it is a built-in array notation function, then the return type of
8173 the function is the element type of the array passed in as array
8174 notation (i.e. the first parameter of the function). */
8176 {
8185 {
8187 {
8190 }
8191 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8192 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8193 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8194 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8195 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8196 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8197 The pre-defined return-type is the correct one. */
8201 }
8202 }
8207 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8208 function call is either the operand of a decltype-specifier or the
8209 right operand of a comma operator that is the operand of a
8210 decltype-specifier, a temporary object is not introduced for the
8211 prvalue. The type of the prvalue may be incomplete. */
8213 {
8219 {
8222 }
8223 }
8225 }
8227 /* Returns the value to use for the in-charge parameter when making a
8228 call to a function with the indicated NAME.
8230 FIXME:Can't we find a neater way to do this mapping? */
8232 tree
8234 {
8245 /* This function should only be called with one of the names listed
8246 above. */
8249 }
8251 /* We've built up a constructor call RET. Complain if it delegates to the
8252 constructor we're currently compiling. */
8254 static void
8256 {
8262 }
8264 /* Build a call to a constructor, destructor, or an assignment
8265 operator for INSTANCE, an expression with class type. NAME
8266 indicates the special member function to call; *ARGS are the
8267 arguments. ARGS may be NULL. This may change ARGS. BINFO
8268 indicates the base of INSTANCE that is to be passed as the `this'
8269 parameter to the member function called.
8271 FLAGS are the LOOKUP_* flags to use when processing the call.
8273 If NAME indicates a complete object constructor, INSTANCE may be
8274 NULL_TREE. In this case, the caller will call build_cplus_new to
8275 store the newly constructed object into a VAR_DECL. */
8277 tree
8280 {
8281 tree fns;
8282 /* The type of the subobject to be constructed or destroyed. */
8283 tree class_type;
8285 tree ret;
8294 {
8295 /* Resolve the name. */
8300 }
8306 /* Handle the special case where INSTANCE is NULL_TREE. */
8309 else
8310 {
8316 /* Convert to the base class, if necessary. */
8319 {
8321 /* For constructors and destructors, either the base is
8322 non-virtual, or it is virtual but we are doing the
8323 conversion from a constructor or destructor for the
8324 complete object. In either case, we can convert
8325 statically. */
8327 else
8328 /* However, for assignment operators, we must convert
8329 dynamically if the base is virtual. */
8332 }
8333 }
8337 /* In C++17, "If the initializer expression is a prvalue and the
8338 cv-unqualified version of the source type is the same class as the class
8339 of the destination, the initializer expression is used to initialize the
8340 destination object." Handle that here to avoid doing overload
8341 resolution. */
8345 {
8348 /* FIXME P0135 doesn't say how to handle direct initialization from a
8349 type with a suitable conversion operator. Let's handle it like
8350 copy-initialization, but allowing explict conversions. */
8353 /* If we're using this to initialize a non-temporary object, don't
8354 require the destructor to be accessible. */
8358 sub_complain,
8359 flags);
8362 && (same_type_ignoring_top_level_qualifiers_p
8364 {
8370 /* Avoid change of behavior on Wunused-var-2.C. */
8373 }
8374 }
8378 /* When making a call to a constructor or destructor for a subobject
8379 that uses virtual base classes, pass down a pointer to a VTT for
8380 the subobject. */
8384 {
8385 tree vtt;
8386 tree sub_vtt;
8388 /* If the current function is a complete object constructor
8389 or destructor, then we fetch the VTT directly.
8390 Otherwise, we look it up using the VTT we were given. */
8398 else
8402 {
8405 }
8408 }
8413 complain);
8424 }
8426 /* Return the NAME, as a C string. The NAME indicates a function that
8427 is a member of TYPE. *FREE_P is set to true if the caller must
8428 free the memory returned.
8430 Rather than go through all of this, we should simply set the names
8431 of constructors and destructors appropriately, and dispense with
8432 ctor_identifier, dtor_identifier, etc. */
8436 {
8439 /* Assume that we will not allocate memory. */
8441 /* Constructors and destructors are special. */
8443 {
8444 pretty_name
8446 /* For a destructor, add the '~'. */
8450 {
8452 /* Remember that we need to free the memory allocated. */
8454 }
8455 }
8457 {
8460 TFF_PLAIN_IDENTIFIER),
8461 NULL);
8462 /* Remember that we need to free the memory allocated. */
8464 }
8465 else
8469 }
8471 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8472 be set, upon return, to the function called. ARGS may be NULL.
8473 This may change ARGS. */
8475 static tree
8479 {
8484 tree optype;
8486 tree name;
8489 tree call;
8490 tree fn;
8493 tree orig_instance;
8494 tree orig_fns;
8500 /* We don't know what function we're going to call, yet. */
8509 {
8513 }
8518 /* Dismantle the baselink to collect all the information we need. */
8526 {
8530 }
8541 {
8546 }
8549 /* Under DR 147 A::A() is an invalid constructor call,
8550 not a functional cast. */
8552 {
8562 complain);
8564 }
8566 /* Figure out whether to skip the first argument for the error
8567 message we will display to users if an error occurs. We don't
8568 want to display any compiler-generated arguments. The "this"
8569 pointer hasn't been added yet. However, we must remove the VTT
8570 pointer if this is a call to a base-class constructor or
8571 destructor. */
8574 {
8575 /* Callers should explicitly indicate whether they want to construct
8576 the complete object or just the part without virtual bases. */
8578 /* Similarly for destructors. */
8580 /* Remove the VTT pointer, if present. */
8584 }
8586 /* Process the argument list. */
8588 {
8592 }
8594 /* Consider the object argument to be used even if we end up selecting a
8595 static member function. */
8598 /* It's OK to call destructors and constructors on cv-qualified objects.
8599 Therefore, convert the INSTANCE to the unqualified type, if
8600 necessary. */
8603 {
8605 {
8609 }
8610 }
8614 /* For the overload resolution we need to find the actual `this`
8615 that would be captured if the call turns out to be to a
8616 non-static member function. Do not actually capture it at this
8617 point. */
8619 /* Constructors don't use the enclosing 'this'. */
8621 else
8624 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8627 /* The number of arguments artificial parms in ARGS; we subtract one because
8628 there's no 'this' in ARGS. */
8631 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8632 initializer, not T({ }). */
8636 {
8643 /* If the initializer list has no elements and T is a class type with
8644 a default constructor, the object is value-initialized. Handle
8645 this here so we don't need to handle it wherever we use
8646 build_special_member_call. */
8649 /* For a user-provided default constructor, use the normal
8650 mechanisms so that protected access works. */
8655 /* If BASETYPE is an aggregate, we need to do aggregate
8656 initialization. */
8658 {
8661 }
8664 {
8670 }
8672 /* Otherwise go ahead with overload resolution. */
8677 }
8678 else
8679 {
8683 }
8688 {
8690 {
8697 else
8698 {
8702 {
8705 }
8713 }
8715 }
8717 }
8718 else
8719 {
8722 {
8725 tree arglist;
8728 {
8736 else
8742 }
8744 }
8745 else
8746 {
8754 {
8755 /* This is not an error, it is runtime undefined
8756 behavior. */
8765 fn);
8766 }
8771 {
8776 {
8777 /* We captured 'this' in the current lambda now that
8778 we know we really need it. */
8780 }
8782 /* We can't tell until instantiation time whether we can use
8784 else
8785 {
8788 fn);
8790 }
8791 }
8794 {
8795 /* Optimize away vtable lookup if we know that this
8796 function can't be overridden. We need to check if
8797 the context and the type where we found fn are the same,
8798 actually FN might be defined in a different class
8799 type because of a using-declaration. In this case, we
8800 do not want to perform a non-virtual call. */
8802 && same_type_ignoring_top_level_qualifiers_p
8808 /* Now we know what function is being called. */
8811 /* Build the actual CALL_EXPR. */
8813 /* In an expression of the form `a->f()' where `f' turns
8814 out to be a static member function, `a' is
8815 none-the-less evaluated. */
8824 /* An explicit call of the form "x->~X()" has type
8825 "void". However, on platforms where destructors
8826 return "this" (i.e., those where
8827 targetm.cxx.cdtor_returns_this is true), such calls
8828 will appear to have a return value of pointer type
8829 to the low-level call machinery. We do not want to
8830 change the low-level machinery, since we want to be
8831 able to optimize "delete f()" on such platforms as
8832 "operator delete(~X(f()))" (rather than generating
8833 "t = f(), ~X(t), operator delete (t)"). */
8835 }
8836 }
8837 }
8840 {
8846 {
8849 }
8852 call = (build_min_non_dep_call_vec
8856 orig_args));
8861 }
8863 /* Free all the conversions we allocated. */
8870 }
8872 /* Wrapper for above. */
8874 tree
8878 {
8879 tree ret;
8885 }
8887 /* Returns true iff standard conversion sequence ICS1 is a proper
8888 subsequence of ICS2. */
8890 static bool
8892 {
8893 /* We can assume that a conversion of the same code
8894 between the same types indicates a subsequence since we only get
8895 here if the types we are converting from are the same. */
8902 {
8912 /* At this point, ICS1 cannot be a proper subsequence of
8913 ICS2. We can get a USER_CONV when we are comparing the
8914 second standard conversion sequence of two user conversion
8915 sequences. */
8930 }
8931 }
8933 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8934 be any _TYPE nodes. */
8936 bool
8938 {
8942 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8943 considers every class derived from itself. */
8946 }
8948 /* We build the ICS for an implicit object parameter as a pointer
8949 conversion sequence. However, such a sequence should be compared
8950 as if it were a reference conversion sequence. If ICS is the
8951 implicit conversion sequence for an implicit object parameter,
8952 modify it accordingly. */
8954 static void
8956 {
8958 {
8959 /* [over.match.funcs]
8961 For non-static member functions, the type of the
8962 implicit object parameter is "reference to cv X"
8963 where X is the class of which the function is a
8964 member and cv is the cv-qualification on the member
8965 function declaration. */
8967 tree reference_type;
8969 /* The `this' parameter is a pointer to a class type. Make the
8970 implicit conversion talk about a reference to that same class
8971 type. */
8984 }
8985 }
8987 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8988 and return the initial reference binding conversion. Otherwise,
8989 leave *ICS unchanged and return NULL. */
8993 {
8995 {
9000 }
9003 }
9005 /* Compare two implicit conversion sequences according to the rules set out in
9006 [over.ics.rank]. Return values:
9008 1: ics1 is better than ics2
9009 -1: ics2 is better than ics1
9010 0: ics1 and ics2 are indistinguishable */
9012 static int
9014 {
9015 tree from_type1;
9016 tree from_type2;
9017 tree to_type1;
9018 tree to_type2;
9025 /* REF_BINDING is nonzero if the result of the conversion sequence
9026 is a reference type. In that case REF_CONV is the reference
9027 binding conversion. */
9031 /* Compare badness before stripping the reference conversion. */
9037 /* Handle implicit object parameters. */
9041 /* Handle reference parameters. */
9045 /* List-initialization sequence L1 is a better conversion sequence than
9046 list-initialization sequence L2 if L1 converts to
9047 std::initializer_list<X> for some X and L2 does not. */
9053 /* [over.ics.rank]
9055 When comparing the basic forms of implicit conversion sequences (as
9056 defined in _over.best.ics_)
9058 --a standard conversion sequence (_over.ics.scs_) is a better
9059 conversion sequence than a user-defined conversion sequence
9060 or an ellipsis conversion sequence, and
9062 --a user-defined conversion sequence (_over.ics.user_) is a
9063 better conversion sequence than an ellipsis conversion sequence
9064 (_over.ics.ellipsis_). */
9065 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9066 mismatch. If both ICS are bad, we try to make a decision based on
9067 what would have happened if they'd been good. This is not an
9068 extension, we'll still give an error when we build up the call; this
9069 just helps us give a more helpful error message. */
9079 /* Both conversions are ellipsis conversions. */
9082 /* User-defined conversion sequence U1 is a better conversion sequence
9083 than another user-defined conversion sequence U2 if they contain the
9084 same user-defined conversion operator or constructor and if the sec-
9085 ond standard conversion sequence of U1 is better than the second
9086 standard conversion sequence of U2. */
9088 /* Handle list-conversion with the same code even though it isn't always
9089 ranked as a user-defined conversion and it doesn't have a second
9090 standard conversion sequence; it will still have the desired effect.
9091 Specifically, we need to do the reference binding comparison at the
9092 end of this function. */
9095 {
9111 {
9114 }
9115 else
9116 {
9117 /* For ambiguous or aggregate conversions, use the target type as
9118 a proxy for the conversion function. */
9121 }
9123 /* We can just fall through here, after setting up
9124 FROM_TYPE1 and FROM_TYPE2. */
9127 }
9128 else
9129 {
9133 /* We're dealing with two standard conversion sequences.
9135 [over.ics.rank]
9137 Standard conversion sequence S1 is a better conversion
9138 sequence than standard conversion sequence S2 if
9140 --S1 is a proper subsequence of S2 (comparing the conversion
9141 sequences in the canonical form defined by _over.ics.scs_,
9142 excluding any Lvalue Transformation; the identity
9143 conversion sequence is considered to be a subsequence of
9144 any non-identity conversion sequence */
9155 }
9157 /* One sequence can only be a subsequence of the other if they start with
9158 the same type. They can start with different types when comparing the
9159 second standard conversion sequence in two user-defined conversion
9160 sequences. */
9162 {
9167 }
9169 /* [over.ics.rank]
9171 Or, if not that,
9173 --the rank of S1 is better than the rank of S2 (by the rules
9174 defined below):
9176 Standard conversion sequences are ordered by their ranks: an Exact
9177 Match is a better conversion than a Promotion, which is a better
9178 conversion than a Conversion.
9180 Two conversion sequences with the same rank are indistinguishable
9181 unless one of the following rules applies:
9183 --A conversion that does not a convert a pointer, pointer to member,
9184 or std::nullptr_t to bool is better than one that does.
9186 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9187 so that we do not have to check it explicitly. */
9196 /* A conversion from scalar arithmetic type to complex is worse than a
9197 conversion between scalar arithmetic types. */
9204 {
9207 else
9209 }
9215 {
9220 }
9221 /* The rules for pointers to members A::* are just like the rules
9222 for pointers A*, except opposite: if B is derived from A then
9223 A::* converts to B::*, not vice versa. For that reason, we
9224 switch the from_ and to_ variables here. */
9231 {
9236 }
9241 {
9242 /* This was one of the pointer or pointer-like conversions.
9244 [over.ics.rank]
9246 --If class B is derived directly or indirectly from class A,
9247 conversion of B* to A* is better than conversion of B* to
9248 void*, and conversion of A* to void* is better than
9249 conversion of B* to void*. */
9252 {
9254 deref_from_type2))
9257 deref_from_type1))
9259 }
9262 {
9264 {
9266 {
9268 deref_to_type1))
9270 }
9271 /* We know that DEREF_TO_TYPE1 is `void' here. */
9273 deref_to_type2))
9275 }
9276 }
9279 {
9280 /* [over.ics.rank]
9282 --If class B is derived directly or indirectly from class A
9283 and class C is derived directly or indirectly from B,
9285 --conversion of C* to B* is better than conversion of C* to
9286 A*,
9288 --conversion of B* to A* is better than conversion of C* to
9289 A* */
9291 {
9293 deref_to_type2))
9296 deref_to_type1))
9298 }
9300 {
9302 deref_from_type1))
9305 deref_from_type2))
9307 }
9308 }
9309 }
9312 {
9315 /* [over.ics.rank]
9317 --binding of an expression of type C to a reference of type
9318 B& is better than binding an expression of type C to a
9319 reference of type A&
9321 --conversion of C to B is better than conversion of C to A, */
9324 {
9329 }
9330 }
9333 {
9336 /* [over.ics.rank]
9338 --binding of an expression of type B to a reference of type
9339 A& is better than binding an expression of type C to a
9340 reference of type A&,
9342 --conversion of B to A is better than conversion of C to A */
9345 {
9350 }
9351 }
9353 /* [over.ics.rank]
9355 --S1 and S2 differ only in their qualification conversion and yield
9356 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9357 qualification signature of type T1 is a proper subset of the cv-
9358 qualification signature of type T2 */
9362 {
9366 }
9368 /* [over.ics.rank]
9370 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9371 to an implicit object parameter of a non-static member function
9372 declared without a ref-qualifier, and either S1 binds an lvalue
9373 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9374 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9375 draft standard, 13.3.3.2)
9377 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9378 types to which the references refer are the same type except for
9379 top-level cv-qualifiers, and the type to which the reference
9380 initialized by S2 refers is more cv-qualified than the type to
9381 which the reference initialized by S1 refers.
9383 DR 1328 [over.match.best]: the context is an initialization by
9384 conversion function for direct reference binding (13.3.1.6) of a
9385 reference to function type, the return type of F1 is the same kind of
9386 reference (i.e. lvalue or rvalue) as the reference being initialized,
9387 and the return type of F2 is not. */
9390 {
9397 {
9401 /* Don't prefer a bad conversion that drops cv-quals to a bad
9402 conversion with the wrong rvalueness. */
9406 }
9409 {
9413 {
9414 /* Prefer the one that drops fewer cv-quals. */
9419 }
9421 }
9422 }
9424 /* Neither conversion sequence is better than the other. */
9426 }
9428 /* The source type for this standard conversion sequence. */
9430 static tree
9432 {
9434 {
9439 }
9441 }
9443 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9444 a pointer to LOSER and re-running joust to produce the warning if WINNER
9445 is actually used. */
9447 static void
9449 {
9455 }
9457 /* Compare two candidates for overloading as described in
9458 [over.match.best]. Return values:
9460 1: cand1 is better than cand2
9461 -1: cand2 is better than cand1
9462 0: cand1 and cand2 are indistinguishable */
9464 static int
9466 tsubst_flags_t complain)
9467 {
9473 /* Candidates that involve bad conversions are always worse than those
9474 that don't. */
9480 /* If we have two pseudo-candidates for conversions to the same type,
9481 or two candidates for the same function, arbitrarily pick one. */
9486 /* Prefer a non-deleted function over an implicitly deleted move
9487 constructor or assignment operator. This differs slightly from the
9488 wording for issue 1402 (which says the move op is ignored by overload
9489 resolution), but this way produces better error messages. */
9493 {
9500 }
9502 /* a viable function F1
9503 is defined to be a better function than another viable function F2 if
9504 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9505 ICSi(F2), and then */
9507 /* for some argument j, ICSj(F1) is a better conversion sequence than
9508 ICSj(F2) */
9510 /* For comparing static and non-static member functions, we ignore
9511 the implicit object parameter of the non-static function. The
9512 standard says to pretend that the static function has an object
9513 parm, but that won't work with operator overloading. */
9516 {
9522 /* We're comparing a near-match list constructor and a near-match
9523 non-list constructor. Just treat them as unordered. */
9530 else
9531 {
9534 }
9535 }
9538 {
9544 {
9546 && warn_sign_promo
9558 {
9565 else
9570 {
9574 }
9575 else
9577 }
9580 {
9583 }
9585 }
9586 }
9588 /* warn about confusing overload resolution for user-defined conversions,
9589 either between a constructor and a conversion op, or between two
9590 conversion ops. */
9595 {
9601 else
9604 /* We don't want to complain about `X::operator T1 ()'
9605 beating `X::operator T2 () const', when T2 is a no less
9606 cv-qualified version of T1. */
9609 {
9614 {
9617 }
9620 }
9621 else
9627 {
9634 {
9636 }
9637 }
9638 else
9640 }
9645 /* DR 495 moved this tiebreaker above the template ones. */
9646 /* or, if not that,
9647 the context is an initialization by user-defined conversion (see
9648 _dcl.init_ and _over.match.user_) and the standard conversion
9649 sequence from the return type of F1 to the destination type (i.e.,
9650 the type of the entity being initialized) is a better conversion
9651 sequence than the standard conversion sequence from the return type
9652 of F2 to the destination type. */
9655 {
9659 }
9661 /* or, if not that,
9662 F1 is a non-template function and F2 is a template function
9663 specialization. */
9670 /* or, if not that,
9671 F1 and F2 are template functions and the function template for F1 is
9672 more specialized than the template for F2 according to the partial
9673 ordering rules. */
9676 {
9677 winner = more_specialized_fn
9680 /* [temp.func.order]: The presence of unused ellipsis and default
9681 arguments has no effect on the partial ordering of function
9682 templates. add_function_candidate() will not have
9683 counted the "this" argument for constructors. */
9687 }
9689 // C++ Concepts
9690 // or, if not that, F1 is more constrained than F2.
9692 {
9696 }
9698 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
9700 {
9702 /* We distinguish between candidates from an explicit deduction guide and
9703 candidates built from a constructor based on DECL_ARTIFICIAL. */
9710 {
9711 /* Prefer the special copy guide over a declared copy/move
9712 constructor. */
9718 /* Prefer a candidate generated from a non-template constructor. */
9723 }
9724 }
9726 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
9727 for all arguments the corresponding parameters of F1 and F2 have the same
9728 type (CWG 2273/2277). */
9733 {
9747 {
9749 {
9754 }
9757 }
9758 }
9760 /* Check whether we can discard a builtin candidate, either because we
9761 have two identical ones or matching builtin and non-builtin candidates.
9763 (Pedantically in the latter case the builtin which matched the user
9764 function should not be added to the overload set, but we spot it here.
9766 [over.match.oper]
9767 ... the builtin candidates include ...
9768 - do not have the same parameter type list as any non-template
9769 non-member candidate. */
9772 {
9778 {
9780 /* Two built-in candidates; arbitrarily pick one. */
9783 /* cand1 is built-in; prefer cand2. */
9785 else
9786 /* cand2 is built-in; prefer cand1. */
9788 }
9789 }
9791 /* For candidates of a multi-versioned function, make the version with
9792 the highest priority win. This version will be checked for dispatching
9793 first. If this version can be inlined into the caller, the front-end
9794 will simply make a direct call to this function. */
9800 {
9806 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9807 is possible that cand1->fn and cand2->fn are function versions but of
9808 different functions. Check types to see if they are versions of the same
9809 function. */
9812 {
9813 /* Always make the version with the higher priority, more
9814 specialized, win. */
9818 else
9820 }
9821 }
9823 /* If the two function declarations represent the same function (this can
9824 happen with declarations in multiple scopes and arg-dependent lookup),
9825 arbitrarily choose one. But first make sure the default args we're
9826 using match. */
9829 {
9836 {
9837 /* Don't crash if the fn is variadic. */
9842 }
9850 {
9853 {
9855 {
9857 {
9859 "default argument mismatch in "
9861 {
9866 }
9867 }
9868 else
9870 }
9871 else
9874 }
9877 }
9880 }
9882 tweak:
9884 /* Extension: If the worst conversion for one candidate is worse than the
9885 worst conversion for the other, take the first. */
9887 {
9892 {
9897 }
9903 {
9904 /* Don't choose a deleted function over ambiguity. */
9908 {
9910 "ISO C++ says that these are ambiguous, even "
9911 "though the worst conversion for the first is better than "
9915 }
9916 else
9919 }
9920 }
9924 }
9926 /* Given a list of candidates for overloading, find the best one, if any.
9927 This algorithm has a worst case of O(2n) (winner is last), and a best
9928 case of O(n/2) (totally ambiguous); much better than a sorting
9929 algorithm. */
9933 {
9938 /* Walk through the list once, comparing each current champ to the next
9939 candidate, knocking out a candidate or two with each comparison. */
9942 {
9946 else
9947 {
9949 {
9954 }
9955 else
9956 {
9959 }
9962 }
9963 }
9965 /* Make sure the champ is better than all the candidates it hasn't yet
9966 been compared to. */
9969 challenger != champ
9972 {
9976 }
9979 }
9981 /* Returns nonzero if things of type FROM can be converted to TO. */
9983 bool
9985 {
9987 /* implicit_conversion only considers user-defined conversions
9988 if it has an expression for the call argument list. */
9992 }
9994 /* Returns nonzero if things of type FROM can be converted to TO with a
9995 standard conversion. */
9997 bool
9999 {
10001 }
10003 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10005 bool
10007 tsubst_flags_t complain)
10008 {
10013 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10015 /* We want to discard any access checks done for this test,
10016 as we might not be in the appropriate access context and
10017 we'll do the check again when we actually perform the
10018 conversion. */
10025 /* Discard the access checks now. */
10027 /* Free all the conversions we allocated. */
10031 }
10033 /* Like can_convert_arg, but allows dubious conversions as well. */
10035 bool
10037 tsubst_flags_t complain)
10038 {
10042 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10044 /* Try to perform the conversion. */
10047 /* Free all the conversions we allocated. */
10051 }
10053 /* Convert EXPR to TYPE. Return the converted expression.
10055 Note that we allow bad conversions here because by the time we get to
10056 this point we are committed to doing the conversion. If we end up
10057 doing a bad conversion, convert_like will complain. */
10059 tree
10062 {
10070 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10078 {
10080 {
10081 /* If expr has unknown type, then it is an overloaded function.
10082 Call instantiate_type to get good error messages. */
10087 else
10090 }
10092 }
10094 {
10095 /* In a template, we are only concerned about determining the
10096 type of non-dependent expressions, so we do not have to
10097 perform the actual conversion. But for initializers, we
10098 need to be able to perform it at instantiation
10099 (or instantiate_non_dependent_expr) time. */
10103 }
10104 else
10107 /* Free all the conversions we allocated. */
10111 }
10113 tree
10115 {
10117 LOOKUP_IMPLICIT);
10118 }
10120 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10121 permitted. If the conversion is valid, the converted expression is
10122 returned. Otherwise, NULL_TREE is returned, except in the case
10123 that TYPE is a class type; in that case, an error is issued. If
10124 C_CAST_P is true, then this direct-initialization is taking
10125 place as part of a static_cast being attempted as part of a C-style
10126 cast. */
10128 tree
10130 tree expr,
10132 tsubst_flags_t complain)
10133 {
10139 /* [dcl.init]
10141 If the destination type is a (possibly cv-qualified) class type:
10143 -- If the initialization is direct-initialization ...,
10144 constructors are considered. ... If no constructor applies, or
10145 the overload resolution is ambiguous, the initialization is
10146 ill-formed. */
10148 {
10154 }
10156 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10160 c_cast_p,
10164 else
10167 c_cast_p,
10168 complain);
10170 /* Free all the conversions we allocated. */
10174 }
10176 /* When initializing a reference that lasts longer than a full-expression,
10177 this special rule applies:
10179 [class.temporary]
10181 The temporary to which the reference is bound or the temporary
10182 that is the complete object to which the reference is bound
10183 persists for the lifetime of the reference.
10185 The temporaries created during the evaluation of the expression
10186 initializing the reference, except the temporary to which the
10187 reference is bound, are destroyed at the end of the
10188 full-expression in which they are created.
10190 In that case, we store the converted expression into a new
10191 VAR_DECL in a new scope.
10193 However, we want to be careful not to create temporaries when
10194 they are not required. For example, given:
10196 struct B {};
10197 struct D : public B {};
10198 D f();
10199 const B& b = f();
10201 there is no need to copy the return value from "f"; we can just
10202 extend its lifetime. Similarly, given:
10204 struct S {};
10205 struct T { operator S(); };
10206 T t;
10207 const S& s = t;
10209 we can extend the lifetime of the return value of the conversion
10210 operator.
10212 The next several functions are involved in this lifetime extension. */
10214 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10215 reference is being bound to a temporary. Create and return a new
10216 VAR_DECL with the indicated TYPE; this variable will store the value to
10217 which the reference is bound. */
10219 tree
10221 {
10224 /* Register the variable. */
10227 {
10228 /* Namespace-scope or local static; give it a mangled name. */
10229 /* FIXME share comdat with decl? */
10240 }
10241 else
10242 /* Create a new cleanup level if necessary. */
10246 }
10248 /* EXPR is the initializer for a variable DECL of reference or
10249 std::initializer_list type. Create, push and return a new VAR_DECL
10250 for the initializer so that it will live as long as DECL. Any
10251 cleanup for the new variable is returned through CLEANUP, and the
10252 code to initialize the new variable is returned through INITP. */
10254 static tree
10257 {
10258 tree init;
10259 tree type;
10260 tree var;
10262 /* Create the temporary variable. */
10266 /* If the rvalue is the result of a function call it will be
10267 a TARGET_EXPR. If it is some other construct (such as a
10268 member access expression where the underlying object is
10269 itself the result of a function call), turn it into a
10270 TARGET_EXPR here. It is important that EXPR be a
10271 TARGET_EXPR below since otherwise the INIT_EXPR will
10272 attempt to make a bitwise copy of EXPR to initialize
10273 VAR. */
10279 {
10283 }
10285 /* Recursively extend temps in this initializer. */
10289 /* Any reference temp has a non-trivial initializer. */
10292 /* If the initializer is constant, put it in DECL_INITIAL so we get
10293 static initialization and use in constant expressions. */
10296 {
10298 {
10299 /* 5.19 says that a constant expression can include an
10300 lvalue-rvalue conversion applied to "a glvalue of literal type
10301 that refers to a non-volatile temporary object initialized
10302 with a constant expression". Rather than try to communicate
10303 that this VAR_DECL is a temporary, just mark it constexpr.
10305 Currently this is only useful for initializer_list temporaries,
10306 since reference vars can't appear in constant expressions. */
10310 }
10313 }
10314 else
10315 /* Create the INIT_EXPR that will initialize the temporary
10316 variable. */
10319 {
10324 else
10325 {
10329 }
10331 /* We must be careful to destroy the temporary only
10332 after its initialization has taken place. If the
10333 initialization throws an exception, then the
10334 destructor should not be run. We cannot simply
10335 transform INIT into something like:
10337 (INIT, ({ CLEANUP_STMT; }))
10339 because emit_local_var always treats the
10340 initializer as a full-expression. Thus, the
10341 destructor would run too early; it would run at the
10342 end of initializing the reference variable, rather
10343 than at the end of the block enclosing the
10344 reference variable.
10346 The solution is to pass back a cleanup expression
10347 which the caller is responsible for attaching to
10348 the statement tree. */
10349 }
10350 else
10351 {
10354 {
10357 tls_aggregates);
10358 else
10360 static_aggregates);
10361 }
10362 else
10363 /* Check whether the dtor is callable. */
10365 }
10366 /* Avoid -Wunused-variable warning (c++/38958). */
10373 }
10375 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10376 initializing a variable of that TYPE. */
10378 tree
10381 {
10389 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10395 {
10397 {
10406 else
10410 }
10412 }
10415 /* Perform the conversion. */
10418 /* We gave an error in build_user_type_conversion_1. */
10420 else
10423 /* Free all the conversions we allocated. */
10427 }
10429 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10430 which is bound either to a reference or a std::initializer_list. */
10432 static tree
10434 {
10439 {
10443 }
10446 /* Deal with binding to a subobject. */
10450 {
10458 }
10460 }
10462 /* INIT is part of the initializer for DECL. If there are any
10463 reference or initializer lists being initialized, extend their
10464 lifetime to match that of DECL. */
10466 tree
10468 {
10474 else
10475 {
10480 {
10482 {
10483 /* The temporary array underlying a std::initializer_list
10484 is handled like a reference temporary. */
10488 }
10489 else
10490 {
10496 }
10500 }
10501 }
10504 }
10506 /* Returns true iff an initializer for TYPE could contain temporaries that
10507 need to be extended because they are bound to references or
10508 std::initializer_list. */
10510 bool
10512 {
10517 {
10524 }
10526 }
10528 /* Returns true iff TYPE is some variant of std::initializer_list. */
10530 bool
10532 {
10537 /* Look through typedefs. */
10542 }
10544 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10545 will accept an argument list of a single std::initializer_list<T>. */
10547 bool
10549 {
10551 tree arg;
10563 /* There are more non-defaulted parms. */
10567 }