| blob | 6533214799d1bf40d68cf8b3bd3d104ebd2a4b75 |
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, 0, \
153 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
154 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
162 tsubst_flags_t);
174 static void add_builtin_candidates
177 static void add_builtin_candidate
181 static void build_builtin_candidate
191 tsubst_flags_t);
193 tsubst_flags_t);
213 tsubst_flags_t);
217 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
218 NAME can take many forms... */
220 bool
222 {
223 /* Just accept something we've already complained about. */
232 {
238 else
240 }
241 else
242 {
243 /* In the case of:
245 template <class T> struct S { ~S(); };
246 int i;
247 i.~S();
249 NAME will be a class template. */
252 }
257 }
259 /* We want the address of a function or method. We avoid creating a
260 pointer-to-member function. */
262 tree
264 {
267 /* We have to do these by hand to avoid real pointer to member
268 functions. */
270 {
272 {
276 complain);
277 }
279 }
280 else
284 }
286 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
287 POINTER_TYPE to those. Note, pointer to member function types
288 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
289 two variants. build_call_a is the primitive taking an array of
290 arguments, while build_call_n is a wrapper that handles varargs. */
292 tree
294 {
297 else
298 {
308 }
309 }
311 /* Update various flags in cfun and the call itself based on what is being
312 called. Split out of build_call_a so that bot_manip can use it too. */
314 void
316 {
320 /* We check both the decl and the type; a function may be known not to
321 throw without being declared throw(). */
335 }
337 tree
339 {
340 tree decl;
341 tree result_type;
342 tree fntype;
352 /* An rvalue has no cv-qualifiers. */
363 {
364 /* We invoke build_call directly for several library
365 functions. These may have been declared normally if
366 we're building libgcc, so we can't just check
367 DECL_ARTIFICIAL. */
372 }
379 && flag_new_inheriting_ctors
383 /* Pass arguments directly to the inherited constructor. */
386 /* Don't pass empty class objects by value. This is useful
387 for tags in STL, which are used to control overload resolution.
388 We don't need to handle other cases of copying empty classes. */
391 {
395 {
399 }
400 }
403 }
405 /* New overloading code. */
412 };
414 /* Information for providing diagnostics about why overloading failed. */
417 rr_none,
418 rr_arity,
419 rr_explicit_conversion,
420 rr_template_conversion,
421 rr_arg_conversion,
422 rr_bad_arg_conversion,
423 rr_template_unification,
424 rr_invalid_copy,
425 rr_inherited_ctor,
426 rr_constraint_failure
427 };
430 /* The index of the argument, 0-based. */
432 /* The actual argument or its type. */
433 tree from;
434 /* The type of the parameter. */
435 tree to_type;
436 };
441 /* Information about an arity mismatch. */
443 /* The expected number of arguments. */
445 /* The actual number of arguments in the call. */
447 /* Whether the call was a varargs call. */
450 /* Information about an argument conversion mismatch. */
452 /* Same, but for bad argument conversions. */
454 /* Information about template unification failures. These are the
455 parameters passed to fn_type_unification. */
457 tree tmpl;
458 tree explicit_targs;
462 tree return_type;
463 unification_kind_t strict;
466 /* Information about template instantiation failures. These are the
467 parameters passed to instantiate_template. */
469 tree tmpl;
470 tree targs;
473 };
476 /* The FUNCTION_DECL that will be called if this candidate is
477 selected by overload resolution. */
478 tree fn;
479 /* If not NULL_TREE, the first argument to use when calling this
480 function. */
481 tree first_arg;
482 /* The rest of the arguments to use when calling this function. If
483 there are no further arguments this may be NULL or it may be an
484 empty vector. */
486 /* The implicit conversion sequences for each of the arguments to
487 FN. */
489 /* The number of implicit conversion sequences. */
491 /* If FN is a user-defined conversion, the standard conversion
492 sequence from the type returned by FN to the desired destination
493 type. */
496 /* If FN is a member function, the binfo indicating the path used to
497 qualify the name of FN at the call site. This path is used to
498 determine whether or not FN is accessible if it is selected by
499 overload resolution. The DECL_CONTEXT of FN will always be a
500 (possibly improper) base of this binfo. */
501 tree access_path;
502 /* If FN is a non-static member function, the binfo indicating the
503 subobject to which the `this' pointer should be converted if FN
504 is selected by overload resolution. The type pointed to by
505 the `this' pointer must correspond to the most derived class
506 indicated by the CONVERSION_PATH. */
507 tree conversion_path;
508 tree template_decl;
509 tree explicit_targs;
514 /* The flags active in add_candidate. */
516 };
518 /* Returns true iff T is a null pointer constant in the sense of
519 [conv.ptr]. */
521 bool
523 {
526 /* [conv.ptr]
528 A null pointer constant is an integral constant expression
529 (_expr.const_) rvalue of integer type that evaluates to zero or
530 an rvalue of type std::nullptr_t. */
535 {
536 /* Core issue 903 says only literal 0 is a null pointer constant. */
543 }
545 {
550 }
553 }
555 /* Returns true iff T is a null member pointer value (4.11). */
557 bool
559 {
568 else
570 }
572 /* Returns nonzero if PARMLIST consists of only default parms,
573 ellipsis, and/or undeduced parameter packs. */
575 bool
577 {
584 }
586 /* Allocate N bytes of memory from the conversion obstack. The memory
587 is zeroed before being returned. */
591 {
594 {
597 }
601 }
603 /* Allocate rejection reasons. */
607 {
612 }
616 {
622 }
626 {
633 }
637 {
644 }
648 {
654 }
658 {
664 }
671 {
678 /* Copy args to our own storage. */
686 }
690 {
692 }
696 {
699 }
703 {
706 }
708 // Build a constraint failure record, saving information into the
709 // template_instantiation field of the rejection. If FN is not a template
710 // declaration, the TMPL member is the FN declaration and TARGS is empty.
714 {
717 {
720 }
721 else
722 {
725 }
727 }
729 /* Dynamically allocate a conversion. */
733 {
738 }
740 /* Make sure that all memory on the conversion obstack has been
741 freed. */
743 void
745 {
749 }
751 /* Dynamically allocate an array of N conversions. */
755 {
757 }
761 {
765 /* Note that the caller is responsible for filling in t->cand for
766 user-defined conversions. */
772 {
789 }
795 }
797 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
798 specialization of std::initializer_list<T>, if such a conversion is
799 possible. */
803 {
809 tree val;
811 /* Within a list-initialization we can have more user-defined
812 conversions. */
814 /* But no narrowing conversions. */
817 /* Can't make an array of these types. */
824 {
825 conversion *sub
832 }
840 {
848 }
851 }
853 /* Return the next conversion of the conversion chain (if applicable),
854 or NULL otherwise. Please use this function instead of directly
855 accessing fields of struct conversion. */
859 {
866 }
868 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
869 is a valid aggregate initializer for array type ATYPE. */
871 static bool
873 {
877 {
883 else
885 complain);
888 }
890 }
892 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
893 aggregate class, if such a conversion is possible. */
897 {
903 /* We already called reshape_init in implicit_conversion. */
905 /* The conversions within the init-list aren't affected by the enclosing
906 context; they're always simple copy-initialization. */
910 {
912 tree val;
920 /* Value-initialization of reference is ill-formed. */
922 else
923 {
927 }
933 else
935 complain);
942 }
954 }
956 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
957 array type, if such a conversion is possible. */
961 {
966 tree val;
971 /* We might need to propagate the size from the element to the array. */
976 {
980 }
985 {
986 conversion *sub
998 }
1007 }
1009 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1010 complex type, if such a conversion is possible. */
1014 tsubst_flags_t complain)
1015 {
1020 tree val;
1031 {
1032 conversion *sub
1044 }
1053 }
1055 /* Build a representation of the identity conversion from EXPR to
1056 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1060 {
1068 }
1070 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1071 were multiple user-defined conversions to accomplish the job.
1072 Build a conversion that indicates that ambiguity. */
1076 {
1084 }
1086 tree
1088 {
1092 }
1094 /* Returns the standard conversion path (see [conv]) from type FROM to type
1095 TO, if any. For proper handling of null pointer constants, you must
1096 also pass the expression EXPR to convert from. If C_CAST_P is true,
1097 this conversion is coming from a C-style cast. */
1102 {
1106 tree qualified_to;
1110 {
1113 }
1119 {
1121 {
1127 }
1129 {
1130 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1133 }
1134 }
1141 {
1145 }
1146 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1147 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1148 express the copy constructor call required by copy-initialization. */
1150 {
1152 {
1153 tree bitfield_type;
1156 {
1159 }
1160 }
1164 }
1166 /* Allow conversion between `__complex__' data types. */
1168 {
1169 /* The standard conversion sequence to convert FROM to TO is
1170 the standard conversion sequence to perform componentwise
1171 conversion. */
1174 complain);
1177 {
1180 }
1181 else
1185 }
1188 {
1192 }
1194 /* [conv.ptr]
1195 A null pointer constant can be converted to a pointer type; ... A
1196 null pointer constant of integral type can be converted to an
1197 rvalue of type std::nullptr_t. */
1205 {
1206 /* For backwards brain damage compatibility, allow interconversion of
1207 pointers and integers with a pedwarn. */
1210 }
1212 {
1213 /* For backwards brain damage compatibility, allow interconversion of
1214 enums and integers with a pedwarn. */
1217 }
1220 {
1221 tree to_pointee;
1222 tree from_pointee;
1225 {
1229 /* Since this is the target of a pointer, it can't have function
1230 qualifiers, so any TYPE_QUALS must be for attributes const or
1231 noreturn. Strip them. */
1238 }
1239 else
1240 {
1243 }
1247 to_pointee))
1248 ;
1252 {
1254 /* Don't try to apply restrict to void. */
1259 }
1261 {
1266 && (same_type_ignoring_top_level_qualifiers_p
1268 {
1271 }
1274 }
1277 /* [conv.ptr]
1279 An rvalue of type "pointer to cv D," where D is a
1280 class type, can be converted to an rvalue of type
1281 "pointer to cv B," where B is a base class (clause
1282 _class.derived_) of D. If B is an inaccessible
1283 (clause _class.access_) or ambiguous
1284 (_class.member.lookup_) base class of D, a program
1285 that necessitates this conversion is ill-formed.
1286 Therefore, we use DERIVED_FROM_P, and do not check
1287 access or uniqueness. */
1289 {
1290 from_pointee
1296 }
1301 /* In a C-style cast, we ignore CV-qualification because we
1302 are allowed to perform a static_cast followed by a
1303 const_cast. */
1308 /* converting from string constant to char *. */
1312 /* Allow conversions among compatible ObjC pointer types (base
1313 conversions have been already handled above). */
1318 {
1321 }
1322 else
1326 }
1328 {
1342 else
1346 {
1348 tbase,
1354 }
1357 }
1359 {
1360 /* [conv.bool]
1362 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1363 to member type can be converted to a prvalue of type bool. ...
1364 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1365 std::nullptr_t can be converted to a prvalue of type bool; */
1371 {
1382 }
1385 }
1386 /* We don't check for ENUMERAL_TYPE here because there are no standard
1387 conversions to enum type. */
1388 /* As an extension, allow conversion to complex type. */
1390 {
1397 /* Give this a better rank if it's a promotion. */
1401 }
1407 {
1411 /* The derived-to-base conversion indicates the initialization
1412 of a parameter with base type from an object of a derived
1413 type. A temporary object is created to hold the result of
1414 the conversion unless we're binding directly to a reference. */
1416 }
1417 else
1424 }
1426 /* Returns nonzero if T1 is reference-related to T2. */
1428 bool
1430 {
1437 /* [dcl.init.ref]
1439 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1440 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1441 of T2. */
1445 }
1447 /* Returns nonzero if T1 is reference-compatible with T2. */
1449 static bool
1451 {
1452 /* [dcl.init.ref]
1454 "cv1 T1" is reference compatible with "cv2 T2" if
1455 * T1 is reference-related to T2 or
1456 * T2 is "noexcept function" and T1 is "function", where the
1457 function types are otherwise the same,
1458 and cv1 is the same cv-qualification as, or greater cv-qualification
1459 than, cv2. */
1463 }
1465 /* A reference of the indicated TYPE is being bound directly to the
1466 expression represented by the implicit conversion sequence CONV.
1467 Return a conversion sequence for this binding. */
1471 {
1472 tree t;
1479 /* [over.ics.rank]
1481 When a parameter of reference type binds directly
1482 (_dcl.init.ref_) to an argument expression, the implicit
1483 conversion sequence is the identity conversion, unless the
1484 argument expression has a type that is a derived class of the
1485 parameter type, in which case the implicit conversion sequence is
1486 a derived-to-base Conversion.
1488 If the parameter binds directly to the result of applying a
1489 conversion function to the argument expression, the implicit
1490 conversion sequence is a user-defined conversion sequence
1491 (_over.ics.user_), with the second standard conversion sequence
1492 either an identity conversion or, if the conversion function
1493 returns an entity of a type that is a derived class of the
1494 parameter type, a derived-to-base conversion. */
1496 {
1497 /* Represent the derived-to-base conversion. */
1499 /* We will actually be binding to the base-class subobject in
1500 the derived class, so we mark this conversion appropriately.
1501 That way, convert_like knows not to generate a temporary. */
1503 }
1505 }
1507 /* Returns the conversion path from type FROM to reference type TO for
1508 purposes of reference binding. For lvalue binding, either pass a
1509 reference type to FROM or an lvalue expression to EXPR. If the
1510 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1511 the conversion returned. If C_CAST_P is true, this
1512 conversion is coming from a C-style cast. */
1516 tsubst_flags_t complain)
1517 {
1521 tree tfrom;
1524 cp_lvalue_kind gl_kind;
1528 {
1533 }
1536 {
1538 /* DR 1288: Otherwise, if the initializer list has a single element
1539 of type E and ... [T's] referenced type is reference-related to E,
1540 the object or reference is initialized from that element... */
1542 {
1548 {
1552 }
1553 }
1554 /* Otherwise, if T is a reference type, a prvalue temporary of the
1555 type referenced by T is copy-list-initialized or
1556 direct-list-initialized, depending on the kind of initialization
1557 for the reference, and the reference is bound to that temporary. */
1560 skip:;
1561 }
1564 {
1569 else
1571 }
1577 else
1580 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1585 /* Same mask as real_lvalue_p. */
1592 /* Figure out whether or not the types are reference-related and
1593 reference compatible. We have to do this after stripping
1594 references from FROM. */
1596 /* If this is a C cast, first convert to an appropriately qualified
1597 type, so that we can later do a const_cast to the desired type. */
1603 /* Directly bind reference when target expression's type is compatible with
1604 the reference and expression is an lvalue. In DR391, the wording in
1605 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1606 const and rvalue references to rvalues of compatible class type.
1607 We should also do direct bindings for non-class xvalues. */
1609 {
1610 /* [dcl.init.ref]
1612 If the initializer expression
1614 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1615 is reference-compatible with "cv2 T2,"
1617 the reference is bound directly to the initializer expression
1618 lvalue.
1620 [...]
1621 If the initializer expression is an rvalue, with T2 a class type,
1622 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1623 is bound to the object represented by the rvalue or to a sub-object
1624 within that object. */
1630 /* The top-level caller requested that we pretend that the lvalue
1631 be treated as an rvalue. */
1634 /* Handle rvalue reference to function properly. */
1635 conv->rvaluedness_matches_p
1637 else
1638 conv->rvaluedness_matches_p
1643 /* For the purposes of overload resolution, we ignore the fact
1644 this expression is a bitfield or packed field. (In particular,
1645 [over.ics.ref] says specifically that a function with a
1646 non-const reference parameter is viable even if the
1647 argument is a bitfield.)
1649 However, when we actually call the function we must create
1650 a temporary to which to bind the reference. If the
1651 reference is volatile, or isn't const, then we cannot make
1652 a temporary, so we just issue an error when the conversion
1653 actually occurs. */
1656 /* Don't allow binding of lvalues (other than function lvalues) to
1657 rvalue references. */
1663 /* Nor the reverse. */
1674 }
1675 /* [class.conv.fct] A conversion function is never used to convert a
1676 (possibly cv-qualified) object to the (possibly cv-qualified) same
1677 object type (or a reference to it), to a (possibly cv-qualified) base
1678 class of that type (or a reference to it).... */
1681 {
1682 /* [dcl.init.ref]
1684 If the initializer expression
1686 -- has a class type (i.e., T2 is a class type) can be
1687 implicitly converted to an lvalue of type "cv3 T3," where
1688 "cv1 T1" is reference-compatible with "cv3 T3". (this
1689 conversion is selected by enumerating the applicable
1690 conversion functions (_over.match.ref_) and choosing the
1691 best one through overload resolution. (_over.match_).
1693 the reference is bound to the lvalue result of the conversion
1694 in the second case. */
1696 complain);
1699 }
1701 /* From this point on, we conceptually need temporaries, even if we
1702 elide them. Only the cases above are "direct bindings". */
1706 /* [over.ics.rank]
1708 When a parameter of reference type is not bound directly to an
1709 argument expression, the conversion sequence is the one required
1710 to convert the argument expression to the underlying type of the
1711 reference according to _over.best.ics_. Conceptually, this
1712 conversion sequence corresponds to copy-initializing a temporary
1713 of the underlying type with the argument expression. Any
1714 difference in top-level cv-qualification is subsumed by the
1715 initialization itself and does not constitute a conversion. */
1717 /* [dcl.init.ref]
1719 Otherwise, the reference shall be an lvalue reference to a
1720 non-volatile const type, or the reference shall be an rvalue
1721 reference.
1723 We try below to treat this as a bad conversion to improve diagnostics,
1724 but if TO is an incomplete class, we need to reject this conversion
1725 now to avoid unnecessary instantiation. */
1730 /* We're generating a temporary now, but don't bind any more in the
1731 conversion (specifically, don't slice the temporary returned by a
1732 conversion operator). */
1735 /* Core issue 899: When [copy-]initializing a temporary to be bound
1736 to the first parameter of a copy constructor (12.8) called with
1737 a single argument in the context of direct-initialization,
1738 explicit conversion functions are also considered.
1740 So don't set LOOKUP_ONLYCONVERTING in that case. */
1751 {
1752 /* If initializing the temporary used a conversion function,
1753 recalculate the second conversion sequence. */
1757 {
1760 conversion *new_second
1766 }
1767 }
1770 /* This reference binding, unlike those above, requires the
1771 creation of a temporary. */
1775 /* [dcl.init.ref]
1777 Otherwise, the reference shall be an lvalue reference to a
1778 non-volatile const type, or the reference shall be an rvalue
1779 reference. */
1783 /* [dcl.init.ref]
1785 Otherwise, a temporary of type "cv1 T1" is created and
1786 initialized from the initializer expression using the rules for a
1787 non-reference copy initialization. If T1 is reference-related to
1788 T2, cv1 must be the same cv-qualification as, or greater
1789 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1794 }
1796 /* Returns the implicit conversion sequence (see [over.ics]) from type
1797 FROM to type TO. The optional expression EXPR may affect the
1798 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1799 true, this conversion is coming from a C-style cast. */
1804 {
1811 /* Other flags only apply to the primary function in overload
1812 resolution, or after we've chosen one. */
1817 /* FIXME: actually we don't want warnings either, but we can't just
1818 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1819 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1820 We really ought not to issue that warning until we've committed
1821 to that conversion. */
1824 /* Call reshape_init early to remove redundant braces. */
1829 {
1834 }
1838 else
1845 {
1849 /* As an extension, allow list-initialization of _Complex. */
1851 {
1855 }
1857 /* Allow conversion from an initializer-list with one element to a
1858 scalar type. */
1860 {
1862 tree elt;
1868 else
1874 {
1877 /* Too many levels of braces, i.e. '{{1}}'. */
1880 }
1881 }
1884 }
1890 {
1900 {
1904 {
1905 /* "If C is not an initializer-list constructor and the
1906 initializer list has a single element of type cv U, where U is
1907 X or a class derived from X, the implicit conversion sequence
1908 has Exact Match rank if U is X, or Conversion rank if U is
1909 derived from X." */
1915 }
1917 }
1919 /* We used to try to bind a reference to a temporary here, but that
1920 is now handled after the recursive call to this function at the end
1921 of reference_binding. */
1923 }
1926 }
1928 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1929 functions. ARGS will not be changed until a single candidate is
1930 selected. */
1939 {
1957 }
1959 /* Return the number of remaining arguments in the parameter list
1960 beginning with ARG. */
1962 int
1964 {
1969 n++;
1972 }
1974 /* Create an overload candidate for the function or method FN called
1975 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1976 FLAGS is passed on to implicit_conversion.
1978 This does not change ARGS.
1980 CTYPE, if non-NULL, is the type we want to pretend this function
1981 comes from for purposes of overload resolution. */
1988 tsubst_flags_t complain)
1989 {
1993 tree parmnode;
1999 /* At this point we should not see any functions which haven't been
2000 explicitly declared, except for friend functions which will have
2001 been found using argument dependent lookup. */
2004 /* The `this', `in_chrg' and VTT arguments to constructors are not
2005 considered in overload resolution. */
2007 {
2011 {
2014 }
2015 }
2016 else
2022 /* 13.3.2 - Viable functions [over.match.viable]
2023 First, to be a viable function, a candidate function shall have enough
2024 parameters to agree in number with the arguments in the list.
2026 We need to check this first; otherwise, checking the ICSes might cause
2027 us to produce an ill-formed template instantiation. */
2031 {
2035 }
2039 {
2043 }
2045 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2046 parameter of type "reference to cv C" (including such a constructor
2047 instantiated from a template) is excluded from the set of candidate
2048 functions when used to construct an object of type D with an argument list
2049 containing a single argument if C is reference-related to D. */
2051 && flag_new_inheriting_ctors
2053 {
2057 {
2060 }
2061 }
2063 /* Second, for a function to be viable, its constraints must be
2064 satisfied. */
2067 {
2070 }
2072 /* When looking for a function from a subobject from an implicit
2073 copy/move constructor/operator=, don't consider anything that takes (a
2074 reference to) an unrelated type. See c++/44909 and core 1092. */
2076 {
2082 else
2085 {
2088 ctype))
2090 }
2092 /* This only applies at the top level. */
2094 }
2099 /* Third, for F to be a viable function, there shall exist for each
2100 argument an implicit conversion sequence that converts that argument
2101 to the corresponding parameter of F. */
2106 {
2108 tree arg;
2117 else
2126 {
2132 /* The type of the implicit object parameter ('this') for
2133 overload resolution is not always the same as for the
2134 function itself; conversion functions are considered to
2135 be members of the class being converted, and functions
2136 introduced by a using-declaration are considered to be
2137 members of the class that uses them.
2139 Since build_over_call ignores the ICS for the `this'
2140 parameter, we can just change the parm type. */
2142 {
2143 parmtype = cp_build_qualified_type
2146 {
2147 /* If the function has a ref-qualifier, the implicit
2148 object parameter has reference type. */
2151 /* The special handling of 'this' conversions in compare_ics
2152 does not apply if there is a ref-qualifier. */
2154 }
2155 else
2156 {
2160 }
2161 }
2163 /* Core issue 899: When [copy-]initializing a temporary to be bound
2164 to the first parameter of a copy constructor (12.8) called with
2165 a single argument in the context of direct-initialization,
2166 explicit conversion functions are also considered.
2168 So set LOOKUP_COPY_PARM to let reference_binding know that
2169 it's being called in that context. We generalize the above
2170 to handle move constructors and template constructors as well;
2171 the standardese should soon be updated similarly. */
2175 && (same_type_ignoring_top_level_qualifiers_p
2177 {
2180 /* We allow user-defined conversions within init-lists, but
2181 don't list-initialize the copy parm, as that would mean
2182 using two levels of braces for the same type. */
2186 }
2187 else
2193 }
2194 else
2195 {
2199 }
2206 {
2210 }
2213 {
2216 }
2217 }
2219 out:
2222 }
2224 /* Create an overload candidate for the conversion function FN which will
2225 be invoked for expression OBJ, producing a pointer-to-function which
2226 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2227 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2228 passed on to implicit_conversion.
2230 Actually, we don't really care about FN; we care about the type it
2231 converts to. There may be multiple conversion functions that will
2232 convert to that type, and we rely on build_user_type_conversion_1 to
2233 choose the best one; so when we create our candidate, we record the type
2234 instead of the function. */
2240 tsubst_flags_t complain)
2241 {
2259 /* Don't bother looking up the same type twice. */
2264 {
2270 else
2275 {
2279 }
2283 {
2287 }
2288 else
2289 {
2293 }
2300 {
2303 }
2310 }
2314 {
2318 }
2322 }
2324 static void
2328 {
2342 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2343 conversion ops are allowed. We handle that here by just checking for
2344 boolean_type_node because other operators don't ask for it. COND_EXPR
2345 also does contextual conversion to bool for the first operand, but we
2346 handle that in build_conditional_expr, and type1 here is operand 2. */
2351 {
2358 {
2360 /* We need something for printing the candidate. */
2364 }
2366 {
2370 }
2372 }
2374 /* For COND_EXPR we rearranged the arguments; undo that now. */
2376 {
2381 complain);
2384 else
2385 {
2388 boolean_type_node);
2389 }
2390 }
2397 }
2399 static bool
2401 {
2403 }
2405 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2407 static bool
2409 {
2410 /* [over.built]
2412 In this section, the term promoted integral type is used to refer
2413 to those integral types which are preserved by integral promotion
2414 (including e.g. int and long but excluding e.g. char).
2415 Similarly, the term promoted arithmetic type refers to promoted
2416 integral types plus floating types. */
2420 }
2422 /* Create any builtin operator overload candidates for the operator in
2423 question given the converted operand types TYPE1 and TYPE2. The other
2424 args are passed through from add_builtin_candidates to
2425 build_builtin_candidate.
2427 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2428 If CODE is requires candidates operands of the same type of the kind
2429 of which TYPE1 and TYPE2 are, we add both candidates
2430 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2432 static void
2436 tsubst_flags_t complain)
2437 {
2439 {
2447 }
2450 {
2452 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2453 and VQ is either volatile or empty, there exist candidate operator
2454 functions of the form
2455 VQ T& operator++(VQ T&);
2456 T operator++(VQ T&, int);
2457 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2458 type other than bool, and VQ is either volatile or empty, there exist
2459 candidate operator functions of the form
2460 VQ T& operator--(VQ T&);
2461 T operator--(VQ T&, int);
2462 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2463 complete object type, and VQ is either volatile or empty, there exist
2464 candidate operator functions of the form
2465 T*VQ& operator++(T*VQ&);
2466 T*VQ& operator--(T*VQ&);
2467 T* operator++(T*VQ&, int);
2468 T* operator--(T*VQ&, int); */
2474 /* FALLTHRU */
2478 {
2481 }
2484 /* 7 For every cv-qualified or cv-unqualified object type T, there
2485 exist candidate operator functions of the form
2487 T& operator*(T*);
2489 8 For every function type T, there exist candidate operator functions of
2490 the form
2491 T& operator*(T*); */
2500 /* 9 For every type T, there exist candidate operator functions of the form
2501 T* operator+(T*);
2503 10For every promoted arithmetic type T, there exist candidate operator
2504 functions of the form
2505 T operator+(T);
2506 T operator-(T); */
2511 /* FALLTHRU */
2517 /* 11For every promoted integral type T, there exist candidate operator
2518 functions of the form
2519 T operator~(T); */
2526 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2527 is the same type as C2 or is a derived class of C2, T is a complete
2528 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2529 there exist candidate operator functions of the form
2530 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2531 where CV12 is the union of CV1 and CV2. */
2535 {
2543 }
2546 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2547 didate operator functions of the form
2548 LR operator*(L, R);
2549 LR operator/(L, R);
2550 LR operator+(L, R);
2551 LR operator-(L, R);
2552 bool operator<(L, R);
2553 bool operator>(L, R);
2554 bool operator<=(L, R);
2555 bool operator>=(L, R);
2556 bool operator==(L, R);
2557 bool operator!=(L, R);
2558 where LR is the result of the usual arithmetic conversions between
2559 types L and R.
2561 14For every pair of types T and I, where T is a cv-qualified or cv-
2562 unqualified complete object type and I is a promoted integral type,
2563 there exist candidate operator functions of the form
2564 T* operator+(T*, I);
2565 T& operator[](T*, I);
2566 T* operator-(T*, I);
2567 T* operator+(I, T*);
2568 T& operator[](I, T*);
2570 15For every T, where T is a pointer to complete object type, there exist
2571 candidate operator functions of the form112)
2572 ptrdiff_t operator-(T, T);
2574 16For every pointer or enumeration type T, there exist candidate operator
2575 functions of the form
2576 bool operator<(T, T);
2577 bool operator>(T, T);
2578 bool operator<=(T, T);
2579 bool operator>=(T, T);
2580 bool operator==(T, T);
2581 bool operator!=(T, T);
2583 17For every pointer to member type T, there exist candidate operator
2584 functions of the form
2585 bool operator==(T, T);
2586 bool operator!=(T, T); */
2593 {
2596 }
2597 /* FALLTHRU */
2610 {
2613 }
2615 {
2618 }
2619 /* Fall through. */
2635 {
2638 }
2641 {
2644 }
2650 /* FALLTHRU */
2653 {
2656 }
2658 {
2661 }
2664 /* 18For every pair of promoted integral types L and R, there exist candi-
2665 date operator functions of the form
2666 LR operator%(L, R);
2667 LR operator&(L, R);
2668 LR operator^(L, R);
2669 LR operator|(L, R);
2670 L operator<<(L, R);
2671 L operator>>(L, R);
2672 where LR is the result of the usual arithmetic conversions between
2673 types L and R. */
2681 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2685 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2686 type, VQ is either volatile or empty, and R is a promoted arithmetic
2687 type, there exist candidate operator functions of the form
2688 VQ L& operator=(VQ L&, R);
2689 VQ L& operator*=(VQ L&, R);
2690 VQ L& operator/=(VQ L&, R);
2691 VQ L& operator+=(VQ L&, R);
2692 VQ L& operator-=(VQ L&, R);
2694 20For every pair T, VQ), where T is any type and VQ is either volatile
2695 or empty, there exist candidate operator functions of the form
2696 T*VQ& operator=(T*VQ&, T*);
2698 21For every pair T, VQ), where T is a pointer to member type and VQ is
2699 either volatile or empty, there exist candidate operator functions of
2700 the form
2701 VQ T& operator=(VQ T&, T);
2703 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2704 unqualified complete object type, VQ is either volatile or empty, and
2705 I is a promoted integral type, there exist candidate operator func-
2706 tions of the form
2707 T*VQ& operator+=(T*VQ&, I);
2708 T*VQ& operator-=(T*VQ&, I);
2710 23For every triple L, VQ, R), where L is an integral or enumeration
2711 type, VQ is either volatile or empty, and R is a promoted integral
2712 type, there exist candidate operator functions of the form
2714 VQ L& operator%=(VQ L&, R);
2715 VQ L& operator<<=(VQ L&, R);
2716 VQ L& operator>>=(VQ L&, R);
2717 VQ L& operator&=(VQ L&, R);
2718 VQ L& operator^=(VQ L&, R);
2719 VQ L& operator|=(VQ L&, R); */
2723 {
2727 {
2730 }
2731 /* FALLTHRU */
2744 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2757 {
2760 }
2765 }
2770 /* [over.built]
2772 For every pair of promoted arithmetic types L and R, there
2773 exist candidate operator functions of the form
2775 LR operator?(bool, L, R);
2777 where LR is the result of the usual arithmetic conversions
2778 between types L and R.
2780 For every type T, where T is a pointer or pointer-to-member
2781 type, there exist candidate operator functions of the form T
2782 operator?(bool, T, T); */
2786 /* That's OK. */
2789 /* Otherwise, the types should be pointers. */
2793 /* We don't check that the two types are the same; the logic
2794 below will actually create two candidates; one in which both
2795 parameter types are TYPE1, and one in which both parameter
2796 types are TYPE2. */
2807 }
2809 /* Make sure we don't create builtin candidates with dependent types. */
2813 {
2814 /* Try to recover if one of the types is non-dependent. But if
2815 there's only one type, there's nothing we can do. */
2818 /* And we lose if both are dependent. */
2821 /* Or if they have different forms. */
2829 }
2831 /* If we're dealing with two pointer types or two enumeral types,
2832 we need candidates for both of them. */
2841 {
2843 {
2845 error_mark_node,
2846 error_mark_node,
2847 CPO_CONVERSION,
2848 tf_none);
2850 {
2851 build_builtin_candidate
2855 }
2856 }
2858 build_builtin_candidate
2860 build_builtin_candidate
2863 }
2865 build_builtin_candidate
2867 }
2869 tree
2871 {
2877 }
2879 /* There are three conditions of builtin candidates:
2881 1) bool-taking candidates. These are the same regardless of the input.
2882 2) pointer-pair taking candidates. These are generated for each type
2883 one of the input types converts to.
2884 3) arithmetic candidates. According to the standard, we should generate
2885 all of these, but I'm trying not to...
2887 Here we generate a superset of the possible candidates for this particular
2888 case. That is a subset of the full set the standard defines, plus some
2889 other cases which the standard disallows. add_builtin_candidate will
2890 filter out the invalid set. */
2892 static void
2896 {
2900 /* TYPES[i] is the set of possible builtin-operator parameter types
2901 we will consider for the Ith argument. */
2906 {
2909 else
2911 }
2914 {
2915 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2916 and VQ is either volatile or empty, there exist candidate operator
2917 functions of the form
2918 VQ T& operator++(VQ T&); */
2928 /* 24There also exist candidate operator functions of the form
2929 bool operator!(bool);
2930 bool operator&&(bool, bool);
2931 bool operator||(bool, bool); */
2934 build_builtin_candidate
2941 build_builtin_candidate
2959 /* Fall through. */
2963 }
2969 {
2971 ;
2973 {
2974 tree convs;
2982 {
2987 }
2993 {
3006 {
3012 }
3016 }
3017 }
3018 else
3019 {
3024 {
3030 }
3032 }
3033 }
3035 /* Run through the possible parameter types of both arguments,
3036 creating candidates with those parameter types. */
3038 {
3040 tree u;
3044 add_builtin_candidate
3047 else
3048 add_builtin_candidate
3051 }
3055 }
3058 /* If TMPL can be successfully instantiated as indicated by
3059 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3061 TMPL is the template. EXPLICIT_TARGS are any explicit template
3062 arguments. ARGLIST is the arguments provided at the call-site.
3063 This does not change ARGLIST. The RETURN_TYPE is the desired type
3064 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3065 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3066 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3074 tsubst_flags_t complain)
3075 {
3085 tree arg;
3087 tree fn;
3091 /* We don't do deduction on the in-charge parameter, the VTT
3092 parameter or 'this'. */
3094 {
3098 /* We're deducing for a call to the result of a template conversion
3100 else
3102 }
3107 {
3110 else
3112 }
3120 {
3121 /* 12.8/6 says, "A declaration of a constructor for a class X is
3122 ill-formed if its first parameter is of type (optionally cv-qualified)
3123 X and either there are no other parameters or else all other
3124 parameters have default arguments. A member function template is never
3125 instantiated to produce such a constructor signature."
3127 So if we're trying to copy an object of the containing class, don't
3128 consider a template constructor that has a first parameter type that
3129 is just a template parameter, as we would deduce a signature that we
3130 would then reject in the code below. */
3132 {
3137 {
3141 }
3142 }
3143 }
3150 {
3153 }
3157 {
3160 }
3165 args_without_in_chrg,
3166 nargs_without_in_chrg,
3171 {
3172 /* Don't repeat unification later if it already resulted in errors. */
3176 nargs_without_in_chrg,
3178 else
3181 }
3184 {
3187 ctype))
3188 {
3189 /* We're trying to produce a constructor with a prohibited signature,
3190 as discussed above; handle here any cases we didn't catch then,
3191 such as X(X<T>). */
3194 }
3195 }
3198 /* Aha, this is a conversion function. */
3201 else
3206 /* This situation can occur if a member template of a template
3207 class is specialized. Then, instantiate_template might return
3208 an instantiation of the specialization, in which case the
3209 DECL_TI_TEMPLATE field will point at the original
3210 specialization. For example:
3212 template <class T> struct S { template <class U> void f(U);
3213 template <> void f(int) {}; };
3214 S<double> sd;
3215 sd.f(3);
3217 Here, TMPL will be template <class U> S<double>::f(U).
3218 And, instantiate template will give us the specialization
3219 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3220 for this will point at template <class T> template <> S<T>::f(int),
3221 so that we can find the definition. For the purposes of
3222 overload resolution, however, we want the original TMPL. */
3224 else
3229 fail:
3232 }
3241 {
3242 return
3247 }
3249 /* Create an overload candidate for the conversion function template TMPL,
3250 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3251 pointer-to-function which will in turn be called with the argument list
3252 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3253 passed on to implicit_conversion. */
3257 tree obj,
3261 {
3262 /* Making this work broke PR 71117, so until the committee resolves core
3263 issue 2189, let's disable this candidate if there are any viable call
3264 operators. */
3268 return
3272 complain);
3273 }
3275 /* The CANDS are the set of candidates that were considered for
3276 overload resolution. Return the set of viable candidates, or CANDS
3277 if none are viable. If any of the candidates were viable, set
3278 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3279 considered viable only if it is strictly viable. */
3285 {
3291 /* Be strict inside templates, since build_over_call won't actually
3292 do the conversions to get pedwarns. */
3302 {
3306 {
3307 /* Be strict in the presence of a viable candidate. Also if
3308 there are template candidates, so that we get deduction errors
3309 for them instead of silently preferring a bad conversion. */
3312 {
3313 /* Put any spliced near matches back onto the main list so
3314 that we see them if there is no strict match. */
3320 }
3321 }
3324 {
3332 }
3333 else
3335 }
3338 }
3340 static bool
3342 {
3347 }
3349 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3350 words, it is about to become the "this" pointer for a member
3351 function call. Take the address of the object. */
3353 static tree
3355 {
3356 /* In a template, we are only concerned about the type of the
3357 expression, so we can take a shortcut. */
3362 }
3364 /* Returns true iff functions are equivalent. Equivalent functions are
3365 not '==' only if one is a function-local extern function or if
3366 both are extern "C". */
3370 {
3379 }
3381 /* Print information about a candidate being rejected due to INFO. */
3383 static void
3385 {
3390 {
3391 /* Conversion of implicit `this' argument failed. */
3393 /* A bad conversion for 'this' must be discarding cv-quals. */
3396 from);
3397 else
3401 }
3403 {
3408 tf_warning_or_error);
3409 }
3411 /* Conversion of conversion function return value failed. */
3414 else
3417 }
3419 /* Print information about a candidate with WANT parameters and we found
3420 HAVE. */
3422 static void
3424 {
3429 }
3431 /* Print information about one overload candidate CANDIDATE. MSGSTR
3432 is the text to print before the candidate itself.
3434 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3435 to have been run through gettext by the caller. This wart makes
3436 life simpler in print_z_candidates and for the translators. */
3438 static void
3441 {
3451 {
3462 else
3465 }
3472 else
3475 {
3478 }
3479 /* Give the user some information about why this candidate failed. */
3481 {
3485 {
3498 "cannot be converted to %qT with a qualification "
3504 "conversion function specialization to %qT is not an "
3509 /* We use template_unification_error_rejection if unification caused
3510 actual non-SFINAE errors, in which case we don't need to repeat
3511 them here. */
3513 {
3517 }
3518 /* Re-run template unification with diagnostics. */
3522 (make_tree_vec
3533 " a constructor taking a single argument of its own "
3537 {
3541 }
3545 "initialization from an expression of the same or derived "
3550 /* This candidate didn't have any issues or we failed to
3551 handle a particular code. Either way... */
3553 }
3554 }
3555 }
3557 static void
3559 {
3566 /* Remove non-viable deleted candidates. */
3569 {
3574 else
3576 }
3577 /* ...if there are any non-deleted ones. */
3581 /* There may be duplicates in the set of candidates. We put off
3582 checking this condition as long as possible, since we have no way
3583 to eliminate duplicates from a set of functions in less than n^2
3584 time. Now we are about to emit an error message, so it is more
3585 permissible to go slowly. */
3587 {
3589 /* Skip builtin candidates and conversion functions. */
3594 {
3598 else
3600 }
3601 }
3605 }
3607 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3608 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3609 the result of the conversion function to convert it to the final
3610 desired type. Merge the two sequences into a single sequence,
3611 and return the merged sequence. */
3615 {
3621 /* Find the end of the second conversion sequence. */
3623 {
3624 /* The entire sequence is a user-conversion sequence. */
3628 }
3630 /* Replace the identity conversion with the user conversion
3631 sequence. */
3635 }
3637 /* Handle overload resolution for initializing an object of class type from
3638 an initializer list. First we look for a suitable constructor that
3639 takes a std::initializer_list; if we don't find one, we then look for a
3640 non-list constructor.
3642 Parameters are as for add_candidates, except that the arguments are in
3643 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3644 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3646 static void
3653 tsubst_flags_t complain)
3654 {
3657 /* We're looking for a ctor for list-initialization. */
3659 /* And we don't allow narrowing conversions. We also use this flag to
3660 avoid the copy constructor call for copy-list-initialization. */
3666 /* Always use the default constructor if the list is empty (DR 990). */
3669 ;
3670 /* If the class has a list ctor, try passing the list as a single
3671 argument first, but only consider list ctors. */
3673 {
3680 }
3682 /* Expand the CONSTRUCTOR into a new argument vec. */
3690 /* We aren't looking for list-ctors anymore. */
3692 /* We allow more user-defined conversions within an init-list. */
3698 }
3700 /* Returns the best overload candidate to perform the requested
3701 conversion. This function is used for three the overloading situations
3702 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3703 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3704 per [dcl.init.ref], so we ignore temporary bindings. */
3708 tsubst_flags_t complain)
3709 {
3711 tree fromtype;
3725 /* We represent conversion within a hierarchy using RVALUE_CONV and
3726 BASE_CONV, as specified by [over.best.ics]; these become plain
3727 constructor calls, as specified in [dcl.init]. */
3732 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3733 creating a garbage BASELINK; constructors can't be inherited. */
3736 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3737 a single element. For now, let's handle constructors as before and also
3738 consider conversion operators from the element. */
3745 {
3750 {
3751 /* [class.conv.fct] A conversion function is never used to
3752 convert a (possibly cv-qualified) object to the (possibly
3753 cv-qualified) same object type (or a reference to it), to a
3754 (possibly cv-qualified) base class of that type (or a
3755 reference to it)... */
3756 }
3757 else
3759 }
3766 /* It's OK to bind a temporary for converting constructor arguments, but
3767 not in converting the return value of a conversion operator. */
3773 {
3778 /* We should never try to call the abstract or base constructor
3779 from here. */
3785 {
3786 /* List-initialization. */
3790 }
3791 else
3792 {
3796 }
3799 {
3802 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3803 set, then this is copy-initialization. In that case, "The
3804 result of the call is then used to direct-initialize the
3805 object that is the destination of the copy-initialization."
3806 [dcl.init]
3808 We represent this in the conversion sequence with an
3809 rvalue conversion, which means a constructor call. */
3812 cand->second_conv
3814 }
3815 }
3818 {
3820 /* FIXME see above about C++17. */
3822 else
3824 }
3827 {
3831 /* If we are called to convert to a reference type, we are trying to
3832 find a direct binding, so don't even consider temporaries. If
3833 we don't find a direct binding, the caller will try again to
3834 look for a temporary binding. */
3845 {
3847 conversion *ics
3849 rettype,
3852 complain);
3854 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3855 copy-initialization. In that case, "The result of the
3856 call is then used to direct-initialize the object that is
3857 the destination of the copy-initialization." [dcl.init]
3859 We represent this in the conversion sequence with an
3860 rvalue conversion, which means a constructor call. But
3861 don't add a second rvalue conversion if there's already
3862 one there. Which there really shouldn't be, but it's
3863 harmless since we'd add it here anyway. */
3871 {
3875 }
3878 {
3879 /* 13.3.1.5: For direct-initialization, those explicit
3880 conversion functions that are not hidden within S and
3881 yield type T or a type that can be converted to type T
3882 with a qualification conversion (4.4) are also candidate
3883 functions. */
3884 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3885 I've raised this issue with the committee. --jason 9/2011 */
3888 }
3890 {
3892 cand->reason
3895 }
3898 {
3899 /* 13.3.3.1.2: If the user-defined conversion is specified by
3900 a specialization of a conversion function template, the
3901 second standard conversion sequence shall have exact match
3902 rank. */
3905 }
3906 }
3907 }
3911 {
3915 }
3919 {
3921 {
3925 }
3932 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3933 ambiguous conversion is no worse than another user-defined
3934 conversion. */
3937 }
3939 tree convtype;
3943 /* DR 5: [in the first step of copy-initialization]...if the function
3944 is a constructor, the call initializes a temporary of the
3945 cv-unqualified version of the destination type. */
3947 else
3949 /* Build the user conversion sequence. */
3950 conv = build_conv
3952 convtype,
3958 /* Remember that this was a list-initialization. */
3962 /* Combine it with the second conversion sequence. */
3967 }
3969 /* Wrapper for above. */
3971 tree
3973 tsubst_flags_t complain)
3974 {
3976 tree ret;
3982 {
3985 else
3986 {
3989 }
3990 }
3991 else
3996 }
3998 /* Subroutine of convert_nontype_argument.
4000 EXPR is an argument for a template non-type parameter of integral or
4001 enumeration type. Do any necessary conversions (that are permitted for
4002 non-type arguments) to convert it to the parameter type.
4004 If conversion is successful, returns the converted expression;
4005 otherwise, returns error_mark_node. */
4007 tree
4009 {
4012 tree t;
4020 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4027 /* for a non-type template-parameter of integral or
4028 enumeration type, integral promotions (4.5) and integral
4029 conversions (4.7) are applied. */
4030 /* It should be sufficient to check the outermost conversion step, since
4031 there are no qualification conversions to integer type. */
4034 {
4035 /* A conversion function is OK. If it isn't constexpr, we'll
4036 complain later that the argument isn't constant. */
4038 /* The lvalue-to-rvalue conversion is OK. */
4051 /* fall through. */
4056 }
4060 else
4063 /* Free all the conversions we allocated. */
4067 }
4069 /* Do any initial processing on the arguments to a function call. */
4073 {
4075 tree arg;
4078 {
4082 {
4086 }
4089 }
4091 }
4093 /* Perform overload resolution on FN, which is called with the ARGS.
4095 Return the candidate function selected by overload resolution, or
4096 NULL if the event that overload resolution failed. In the case
4097 that overload resolution fails, *CANDIDATES will be the set of
4098 candidates considered, and ANY_VIABLE_P will be set to true or
4099 false to indicate whether or not any of the candidates were
4100 viable.
4102 The ARGS should already have gone through RESOLVE_ARGS before this
4103 function is called. */
4110 {
4112 tree explicit_targs;
4123 /* Check FN. */
4130 {
4134 }
4136 /* Add the various candidate functions. */
4141 LOOKUP_NORMAL,
4147 else
4152 }
4154 /* Print an error message about being unable to build a call to FN with
4155 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4156 be located; CANDIDATES is a possibly empty list of such
4157 functions. */
4159 static void
4162 {
4165 {
4168 }
4177 else
4182 }
4184 /* Return an expression for a call to FN (a namespace-scope function,
4185 or a static member function) with the ARGS. This may change
4186 ARGS. */
4188 tree
4190 tsubst_flags_t complain)
4191 {
4195 tree result;
4198 {
4202 }
4207 /* If this function was found without using argument dependent
4208 lookup, then we want to ignore any undeclared friend
4209 functions. */
4211 {
4216 {
4220 }
4221 }
4223 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4227 complain);
4230 {
4232 {
4233 // If there is a single (non-viable) function candidate,
4234 // let the error be diagnosed by cp_build_function_call_vec.
4239 // Otherwise, emit notes for non-viable candidates.
4241 }
4243 }
4244 else
4245 {
4247 /* If fn is template_id_expr, the call has explicit template arguments
4248 (e.g. func<int>(5)), communicate this info to build_over_call
4249 through flags so that later we can use it to decide whether to warn
4250 about peculiar null pointer conversion. */
4252 {
4253 /* If overload resolution selects a specialization of a
4254 function concept for non-dependent template arguments,
4255 the expression is true if the constraints are satisfied
4256 and false otherwise.
4258 NOTE: This is an extension of Concepts Lite TS that
4259 allows constraints to be used in expressions. */
4261 {
4267 }
4270 }
4273 }
4275 /* Free all the conversions we allocated. */
4279 }
4281 /* Build a call to a global operator new. FNNAME is the name of the
4282 operator (either "operator new" or "operator new[]") and ARGS are
4283 the arguments provided. This may change ARGS. *SIZE points to the
4284 total number of bytes required by the allocation, and is updated if
4285 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4286 be used. If this function determines that no cookie should be
4287 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4288 is not NULL_TREE, it is evaluated before calculating the final
4289 array size, and if it fails, the array size is replaced with
4290 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4291 is non-NULL, it will be set, upon return, to the allocation
4292 function called. */
4294 tree
4299 {
4301 tree fns;
4308 /* Set to (size_t)-1 if the size check fails. */
4310 {
4316 }
4322 /* Based on:
4324 [expr.new]
4326 If this lookup fails to find the name, or if the allocated type
4327 is not a class type, the allocation function's name is looked
4328 up in the global scope.
4330 we disregard block-scope declarations of "operator new". */
4334 {
4339 /* If no aligned allocation function matches, try again without the
4340 alignment. */
4341 }
4343 /* Figure out what function is being called. */
4346 complain);
4348 /* If no suitable function could be found, issue an error message
4349 and give up. */
4351 {
4355 }
4357 /* If a cookie is required, add some extra space. Whether
4358 or not a cookie is required cannot be determined until
4359 after we know which function was called. */
4361 {
4363 tree arg_types;
4366 /* Skip the size_t parameter. */
4368 /* Check the remaining parameters (if any). */
4372 ptr_type_node))
4374 /* If we need a cookie, adjust the number of bytes allocated. */
4376 {
4377 /* Update the total size. */
4380 {
4381 /* Set to (size_t)-1 if the size check fails. */
4385 }
4386 /* Update the argument list to reflect the adjusted size. */
4388 }
4389 else
4391 }
4393 /* Tell our caller which function we decided to call. */
4397 /* Build the CALL_EXPR. */
4399 }
4401 /* Build a new call to operator(). This may change ARGS. */
4403 static tree
4405 {
4419 {
4421 /* It's no good looking for an overloaded operator() on a
4422 pointer-to-member-function. */
4423 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4425 }
4428 {
4432 }
4433 else
4437 {
4441 }
4443 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4447 {
4455 }
4460 {
4469 {
4476 add_template_conv_candidate
4480 else
4484 }
4485 }
4487 /* Be strict here because if we choose a bad conversion candidate, the
4488 errors we get won't mention the call context. */
4491 {
4493 {
4497 }
4499 }
4500 else
4501 {
4504 {
4506 {
4510 }
4512 }
4513 /* Since cand->fn will be a type, not a function, for a conversion
4514 function, we must be careful not to unconditionally look at
4515 DECL_NAME here. */
4519 else
4520 {
4524 else
4528 }
4529 }
4531 /* Free all the conversions we allocated. */
4535 }
4537 /* Wrapper for above. */
4539 tree
4541 {
4542 tree ret;
4547 }
4549 /* Called by op_error to prepare format strings suitable for the error
4550 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4551 and a suffix (controlled by NTYPES). */
4555 {
4565 else
4569 }
4571 static void
4574 {
4579 else
4583 {
4589 else
4601 else
4611 else
4622 else
4632 else
4637 else
4641 else
4646 }
4647 }
4649 /* Return the implicit conversion sequence that could be used to
4650 convert E1 to E2 in [expr.cond]. */
4654 {
4660 /* [expr.cond]
4662 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4663 implicitly converted (clause _conv_) to the type "lvalue reference to
4664 T2", subject to the constraint that in the conversion the
4665 reference must bind directly (_dcl.init.ref_) to an lvalue.
4667 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4668 implicitly converted to the type "rvalue reference to T2", subject to
4669 the constraint that the reference must bind directly. */
4671 {
4674 t1,
4675 e1,
4677 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4679 complain);
4682 }
4684 /* If E2 is a prvalue or if neither of the conversions above can be done
4685 and at least one of the operands has (possibly cv-qualified) class
4686 type: */
4690 /* [expr.cond]
4692 If E1 and E2 have class type, and the underlying class types are
4693 the same or one is a base class of the other: E1 can be converted
4694 to match E2 if the class of T2 is the same type as, or a base
4695 class of, the class of T1, and the cv-qualification of T2 is the
4696 same cv-qualification as, or a greater cv-qualification than, the
4697 cv-qualification of T1. If the conversion is applied, E1 is
4698 changed to an rvalue of type T2 that still refers to the original
4699 source class object (or the appropriate subobject thereof). */
4702 {
4704 {
4709 else
4712 }
4713 else
4715 }
4716 else
4717 /* [expr.cond]
4719 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4720 converted to the type that expression E2 would have if E2 were
4721 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4724 }
4726 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4727 arguments to the conditional expression. */
4729 static tree
4731 tsubst_flags_t complain)
4732 {
4733 tree arg2_type;
4734 tree arg3_type;
4743 /* As a G++ extension, the second argument to the conditional can be
4744 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4745 c'.) If the second operand is omitted, make sure it is
4746 calculated only once. */
4748 {
4756 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4759 else
4761 }
4763 /* If something has already gone wrong, just pass that fact up the
4764 tree. */
4774 {
4777 /* If arg1 is another cond_expr choosing between -1 and 0,
4778 then we can use its comparison. It may help to avoid
4779 additional comparison, produce more accurate diagnostics
4780 and enables folding. */
4790 /* force_rvalue can return error_mark on valid arguments. */
4801 {
4802 /* Rely on the error messages of the scalar version. */
4811 {
4819 }
4823 /* We could pass complain & tf_warning to unsafe_conversion_p,
4824 but the warnings (like Wsign-conversion) have already been
4825 given by the scalar build_conditional_expr_1. We still check
4826 unsafe_conversion_p to forbid truncating long long -> float. */
4828 {
4833 }
4835 {
4840 }
4850 }
4853 {
4859 {
4863 {
4869 }
4871 {
4877 }
4880 }
4881 }
4887 {
4890 "incompatible vector types in conditional expression: "
4894 }
4897 {
4900 }
4902 }
4904 /* [expr.cond]
4906 The first expression is implicitly converted to bool (clause
4907 _conv_). */
4909 LOOKUP_NORMAL);
4913 /* [expr.cond]
4915 If either the second or the third operand has type (possibly
4916 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4917 array-to-pointer (_conv.array_), and function-to-pointer
4918 (_conv.func_) standard conversions are performed on the second
4919 and third operands. */
4923 {
4924 /* Do the conversions. We don't these for `void' type arguments
4925 since it can't have any effect and since decay_conversion
4926 does not handle that case gracefully. */
4934 /* [expr.cond]
4936 One of the following shall hold:
4938 --The second or the third operand (but not both) is a
4939 throw-expression (_except.throw_); the result is of the
4940 type of the other and is an rvalue.
4942 --Both the second and the third operands have type void; the
4943 result is of type void and is an rvalue.
4945 We must avoid calling force_rvalue for expressions of type
4946 "void" because it will complain that their value is being
4947 used. */
4950 {
4952 {
4956 }
4959 }
4962 {
4964 {
4968 }
4971 }
4974 else
4975 {
4977 {
4980 "second operand to the conditional operator "
4981 "is of type %<void%>, but the third operand is "
4983 else
4985 "third operand to the conditional operator "
4986 "is of type %<void%>, but the second operand is "
4988 }
4990 }
4994 }
4995 /* [expr.cond]
4997 Otherwise, if the second and third operand have different types,
4998 and either has (possibly cv-qualified) class type, or if both are
4999 glvalues of the same value category and the same type except for
5000 cv-qualification, an attempt is made to convert each of those operands
5001 to the type of the other. */
5005 arg3_type)
5008 {
5013 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5019 /* [expr.cond]
5021 If both can be converted, or one can be converted but the
5022 conversion is ambiguous, the program is ill-formed. If
5023 neither can be converted, the operands are left unchanged and
5024 further checking is performed as described below. If exactly
5025 one conversion is possible, that conversion is applied to the
5026 chosen operand and the converted operand is used in place of
5027 the original operand for the remainder of this section. */
5032 {
5034 {
5041 else
5043 }
5045 }
5047 {
5051 /* Even if CONV2 is a valid conversion, the result of the
5052 conversion may be invalid. For example, if ARG3 has type
5053 "volatile X", and X does not have a copy constructor
5054 accepting a "volatile X&", then even if ARG2 can be
5055 converted to X, the conversion will fail. */
5059 }
5061 {
5068 }
5070 /* Free all the conversions we allocated. */
5076 /* If, after the conversion, both operands have class type,
5077 treat the cv-qualification of both operands as if it were the
5078 union of the cv-qualification of the operands.
5080 The standard is not clear about what to do in this
5081 circumstance. For example, if the first operand has type
5082 "const X" and the second operand has a user-defined
5083 conversion to "volatile X", what is the type of the second
5084 operand after this step? Making it be "const X" (matching
5085 the first operand) seems wrong, as that discards the
5086 qualification without actually performing a copy. Leaving it
5087 as "volatile X" seems wrong as that will result in the
5088 conditional expression failing altogether, even though,
5089 according to this step, the one operand could be converted to
5090 the type of the other. */
5098 }
5100 /* [expr.cond]
5102 If the second and third operands are glvalues of the same value
5103 category and have the same type, the result is of that type and
5104 value category. */
5108 {
5113 }
5115 /* [expr.cond]
5117 Otherwise, the result is an rvalue. If the second and third
5118 operand do not have the same type, and either has (possibly
5119 cv-qualified) class type, overload resolution is used to
5120 determine the conversions (if any) to be applied to the operands
5121 (_over.match.oper_, _over.built_). */
5125 {
5130 /* Rearrange the arguments so that add_builtin_candidate only has
5131 to know about two args. In build_builtin_candidate, the
5132 arguments are unscrambled. */
5137 COND_EXPR,
5138 NOP_EXPR,
5140 args,
5143 /* [expr.cond]
5145 If the overload resolution fails, the program is
5146 ill-formed. */
5149 {
5154 }
5157 {
5159 {
5162 }
5164 }
5166 /* [expr.cond]
5168 Otherwise, the conversions thus determined are applied, and
5169 the converted operands are used in place of the original
5170 operands for the remainder of this section. */
5179 }
5181 /* [expr.cond]
5183 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5184 and function-to-pointer (_conv.func_) standard conversions are
5185 performed on the second and third operands.
5187 We need to force the lvalue-to-rvalue conversion here for class types,
5188 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5189 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5190 regions. */
5203 /* [expr.cond]
5205 After those conversions, one of the following shall hold:
5207 --The second and third operands have the same type; the result is of
5208 that type. */
5211 /* [expr.cond]
5213 --The second and third operands have arithmetic or enumeration
5214 type; the usual arithmetic conversions are performed to bring
5215 them to a common type, and the result is of that type. */
5220 {
5221 /* In this case, there is always a common type. */
5223 arg3_type);
5226 "implicit conversion from %qT to %qT to "
5228 loc);
5232 {
5236 /* Two enumerators from the same enumeration can have different
5242 }
5249 {
5253 }
5257 }
5258 /* [expr.cond]
5260 --The second and third operands have pointer type, or one has
5261 pointer type and the other is a null pointer constant; pointer
5262 conversions (_conv.ptr_) and qualification conversions
5263 (_conv.qual_) are performed to bring them to their composite
5264 pointer type (_expr.rel_). The result is of the composite
5265 pointer type.
5267 --The second and third operands have pointer to member type, or
5268 one has pointer to member type and the other is a null pointer
5269 constant; pointer to member conversions (_conv.mem_) and
5270 qualification conversions (_conv.qual_) are performed to bring
5271 them to a common type, whose cv-qualification shall match the
5272 cv-qualification of either the second or the third operand.
5273 The result is of the common type. */
5281 {
5284 complain);
5289 }
5292 {
5297 }
5302 valid_operands:
5305 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5306 warn here, because the COND_EXPR will be turned into ARG2. */
5312 /* We can't use result_type below, as fold might have returned a
5313 throw_expr. */
5316 {
5317 /* Expand both sides into the same slot, hopefully the target of
5318 the ?: expression. We used to check for TARGET_EXPRs here,
5319 but now we sometimes wrap them in NOP_EXPRs so the test would
5320 fail. */
5323 /* If this expression is an rvalue, but might be mistaken for an
5324 lvalue, we must add a NON_LVALUE_EXPR. */
5326 }
5327 else
5331 }
5333 /* Wrapper for above. */
5335 tree
5337 tsubst_flags_t complain)
5338 {
5339 tree ret;
5344 }
5346 /* OPERAND is an operand to an expression. Perform necessary steps
5347 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5348 returned. */
5350 static tree
5352 {
5354 {
5357 /* Make sure the template type is instantiated now. */
5359 }
5362 }
5364 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5365 OVERLOAD) to the CANDIDATES, returning an updated list of
5366 CANDIDATES. The ARGS are the arguments provided to the call;
5367 if FIRST_ARG is non-null it is the implicit object argument,
5368 otherwise the first element of ARGS is used if needed. The
5369 EXPLICIT_TARGS are explicit template arguments provided.
5370 TEMPLATE_ONLY is true if only template functions should be
5371 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5372 add_function_candidate. */
5374 static void
5376 tree return_type,
5381 tsubst_flags_t complain)
5382 {
5383 tree ctype;
5387 unification_kind_t strict;
5388 tree fn;
5393 /* Precalculate special handling of constructors and conversion ops. */
5396 {
5400 /* We're doing return_type(x). */
5402 else
5403 /* We're doing x.operator return_type(). */
5405 /* [over.match.funcs] For conversion functions, the function
5406 is considered to be a member of the class of the implicit
5407 object argument for the purpose of defining the type of
5408 the implicit object parameter. */
5410 }
5411 else
5412 {
5414 {
5416 /* For list-initialization we consider explicit constructors
5417 and complain if one is chosen. */
5418 check_converting
5421 }
5422 else
5423 {
5426 }
5429 }
5433 else
5434 /* Delay creating the implicit this parameter until it is needed. */
5438 {
5439 tree fn_first_arg;
5449 /* Figure out which set of arguments to use. */
5451 {
5452 /* If this function is a non-static member and we didn't get an
5453 implicit object argument, move it out of args. */
5455 {
5457 tree arg;
5464 }
5468 }
5469 else
5470 {
5471 /* Otherwise, just use the list of arguments provided. */
5474 }
5478 fn,
5479 ctype,
5480 explicit_targs,
5481 fn_first_arg,
5482 fn_args,
5483 return_type,
5484 access_path,
5485 conversion_path,
5486 flags,
5487 strict,
5488 complain);
5491 fn,
5492 ctype,
5493 fn_first_arg,
5494 fn_args,
5495 access_path,
5496 conversion_path,
5497 flags,
5498 complain);
5499 }
5500 }
5502 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5503 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5505 static int
5507 {
5509 {
5510 // 5. b @= a
5514 // 6. a[b]
5518 // 1. a.b
5519 // Not overloadable (yet).
5520 // 2. a->b
5521 // Only one argument.
5522 // 3. a->*b
5524 // 7. a << b
5526 // 8. a >> b
5532 }
5533 }
5535 static tree
5538 {
5541 tree fnname;
5559 {
5563 }
5564 else
5571 {
5576 /* Use build_op_new_call and build_op_delete_call instead. */
5580 /* Use build_op_call instead. */
5587 /* These are saved for the sake of warn_logical_operator. */
5597 /* These are saved for the sake of maybe_warn_bool_compare. */
5602 /* =, ->, [], () must be non-static member functions. */
5606 /* FALLTHRU */
5614 }
5620 /* Use build_conditional_expr instead. */
5636 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5639 /* Add namespace-scope operators to the list of functions to
5640 consider. */
5652 /* Add class-member operators to the candidate set. */
5654 {
5655 tree fns;
5659 {
5662 }
5670 }
5671 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5672 only non-member functions that have type T1 or reference to
5673 cv-qualified-opt T1 for the first argument, if the first argument
5674 has an enumeration type, or T2 or reference to cv-qualified-opt
5675 T2 for the second argument, if the second argument has an
5676 enumeration type. Filter out those that don't match. */
5678 {
5682 {
5692 {
5698 && (same_type_ignoring_top_level_qualifiers_p
5703 }
5705 /* No argument has an appropriate type, so remove this
5706 candidate function from the list. */
5708 {
5711 }
5712 }
5713 }
5719 {
5722 /* For these, the built-in candidates set is empty
5723 [over.match.oper]/3. We don't want non-strict matches
5724 because exact matches are always possible with built-in
5725 operators. The built-in candidate set for COMPONENT_REF
5726 would be empty too, but since there are no such built-in
5727 operators, we accept non-strict matches for them. */
5734 }
5738 {
5740 {
5743 /* Don't try anything fancy if we're not allowed to produce
5744 errors. */
5748 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5749 distinguish between prefix and postfix ++ and
5750 operator++() was used for both, so we allow this with
5751 -fpermissive. */
5752 else
5753 {
5759 }
5766 else
5772 /* The caller will deal with these. */
5782 {
5783 /* If one of the arguments of the operator represents
5784 an invalid use of member function pointer, try to report
5785 a meaningful error ... */
5790 else
5791 {
5792 /* ... Otherwise, report the more generic
5793 "no matching operator found" error */
5796 }
5797 }
5800 }
5801 }
5802 else
5803 {
5806 {
5808 {
5811 }
5813 }
5815 {
5821 else
5827 {
5832 /* This prevents build_new_function_call from discarding this
5833 function during instantiation of the enclosing template. */
5836 /* Specify evaluation order as per P0145R2. */
5839 {
5850 }
5851 }
5852 }
5853 else
5854 {
5855 /* Give any warnings we noticed during overload resolution. */
5857 {
5861 }
5863 /* Check for comparison of different enum types. */
5865 {
5877 {
5881 }
5885 }
5887 /* We need to strip any leading REF_BIND so that bitfields
5888 don't cause errors. This should not remove any important
5889 conversions, because builtins don't apply to class
5890 objects directly. */
5897 {
5901 else
5904 /* We need to call warn_logical_operator before
5905 converting arg2 to a boolean_type, but after
5906 decaying an enumerator to its value. */
5913 }
5915 {
5920 }
5922 }
5923 }
5925 user_defined_result_ready:
5927 /* Free all the conversions we allocated. */
5933 builtin:
5935 {
5950 /* Fall through. */
5963 /* Fall through. */
5996 complain),
5999 /* The caller will deal with these. */
6007 }
6009 }
6011 /* Wrapper for above. */
6013 tree
6017 {
6018 tree ret;
6024 }
6026 /* CALL was returned by some call-building function; extract the actual
6027 CALL_EXPR from any bits that have been tacked on, e.g. by
6028 convert_from_reference. */
6030 tree
6032 {
6043 }
6045 /* Returns true if FN has two parameters, of which the second has type
6046 size_t. */
6048 static bool
6050 {
6062 }
6064 /* True if T, an allocation function, has std::align_val_t as its second
6065 argument. */
6067 bool
6069 {
6075 }
6077 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6078 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6079 std::align_val_t. */
6081 static bool
6083 {
6087 /* A template instance is never a usual deallocation function,
6088 regardless of its signature. */
6104 }
6106 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6107 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6109 bool
6111 {
6112 /* A template instance is never a usual deallocation function,
6113 regardless of its signature. */
6118 /* If a class T has a member deallocation function named operator delete
6119 with exactly one parameter, then that function is a usual
6120 (non-placement) deallocation function. If class T does not declare
6121 such an operator delete but does declare a member deallocation
6122 function named operator delete with exactly two parameters, the second
6123 of which has type std::size_t (18.2), then this function is a usual
6124 deallocation function. */
6136 }
6138 /* Build a call to operator delete. This has to be handled very specially,
6139 because the restrictions on what signatures match are different from all
6140 other call instances. For a normal delete, only a delete taking (void *)
6141 or (void *, size_t) is accepted. For a placement delete, only an exact
6142 match with the placement new is accepted.
6144 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6145 ADDR is the pointer to be deleted.
6146 SIZE is the size of the memory block to be deleted.
6147 GLOBAL_P is true if the delete-expression should not consider
6148 class-specific delete operators.
6149 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6151 If this call to "operator delete" is being generated as part to
6152 deallocate memory allocated via a new-expression (as per [expr.new]
6153 which requires that if the initialization throws an exception then
6154 we call a deallocation function), then ALLOC_FN is the allocation
6155 function. */
6157 tree
6161 {
6175 /* In [class.free]
6177 If the result of the lookup is ambiguous or inaccessible, or if
6178 the lookup selects a placement deallocation function, the
6179 program is ill-formed.
6181 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6182 {
6186 }
6187 else
6193 /* Strip const and volatile from addr. */
6197 {
6198 /* "A declaration of a placement deallocation function matches the
6199 declaration of a placement allocation function if it has the same
6200 number of parameters and, after parameter transformations (8.3.5),
6201 all parameter types except the first are identical."
6203 So we build up the function type we want and ask instantiate_type
6204 to get it for us. */
6216 /* "If the lookup finds the two-parameter form of a usual deallocation
6217 function (3.7.4.2) and that function, considered as a placement
6218 deallocation function, would have been selected as a match for the
6219 allocation function, the program is ill-formed." */
6221 {
6229 /* But if the class has an operator delete (void *), then that is
6230 the usual deallocation function, so we shouldn't complain
6231 about using the operator delete (void *, size_t). */
6235 {
6240 }
6241 /* Before C++14 a two-parameter global deallocation function is
6242 always a placement deallocation function, but warn if
6243 -Wc++14-compat. */
6245 {
6250 }
6253 {
6255 {
6256 /* Only mention C++14 for namespace-scope delete. */
6259 else
6261 "%qD is a usual (non-placement) deallocation "
6263 }
6264 }
6265 else
6267 ok:;
6268 }
6269 }
6270 else
6271 /* "Any non-placement deallocation function matches a non-placement
6272 allocation function. If the lookup finds a single matching
6273 deallocation function, that function will be called; otherwise, no
6274 deallocation function will be called." */
6277 {
6280 {
6282 {
6285 }
6287 /* -- If the type has new-extended alignment, a function with a
6288 parameter of type std::align_val_t is preferred; otherwise a
6289 function without such a parameter is preferred. If exactly one
6290 preferred function is found, that function is selected and the
6291 selection process terminates. If more than one preferred
6292 function is found, all non-preferred functions are eliminated
6293 from further consideration. */
6295 {
6301 {
6305 }
6306 }
6308 /* -- If the deallocation functions have class scope, the one
6309 without a parameter of type std::size_t is selected. */
6314 /* -- If the type is complete and if, for the second alternative
6315 (delete array) only, the operand is a pointer to a class type
6316 with a non-trivial destructor or a (possibly multi-dimensional)
6317 array thereof, the function with a parameter of type std::size_t
6318 is selected.
6320 -- Otherwise, it is unspecified whether a deallocation function
6321 with a parameter of type std::size_t is selected. */
6322 else
6323 {
6327 /* We need a cookie to determine the array size. */
6329 }
6335 }
6336 }
6338 /* If we have a matching function, call it. */
6340 {
6343 /* If the FN is a member function, make sure that it is
6344 accessible. */
6347 complain);
6349 /* Core issue 901: It's ok to new a type with deleted delete. */
6354 {
6355 /* The placement args might not be suitable for overload
6356 resolution at this point, so build the call directly. */
6366 }
6367 else
6368 {
6369 tree ret;
6375 {
6378 }
6382 }
6383 }
6385 /* [expr.new]
6387 If no unambiguous matching deallocation function can be found,
6388 propagating the exception does not cause the object's memory to
6389 be freed. */
6391 {
6395 alloc_fn);
6397 }
6403 }
6405 /* If the current scope isn't allowed to access DECL along
6406 BASETYPE_PATH, give an error. The most derived class in
6407 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6408 the declaration to use in the error diagnostic. */
6410 bool
6412 tsubst_flags_t complain)
6413 {
6418 {
6419 /* 7.3.3/18: The additional constructors are accessible if they would be
6420 accessible when used to construct an object of the corresponding base
6421 class. */
6424 }
6427 {
6429 {
6433 {
6437 }
6439 {
6443 }
6444 else
6445 {
6448 }
6449 }
6451 }
6454 }
6456 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6457 bitwise or of LOOKUP_* values. If any errors are warnings are
6458 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6459 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6460 to NULL. */
6462 static tree
6465 {
6471 /* If the source is a packed field, calling the copy constructor will require
6472 binding the field to the reference parameter to the copy constructor, and
6473 we'll end up with an infinite loop. If we can use a bitwise copy, then
6474 do that now. */
6490 }
6492 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6493 EXPR is implicitly converted to type TOTYPE.
6494 FN and ARGNUM are used for diagnostics. */
6496 static void
6498 {
6499 /* Issue warnings about peculiar, but valid, uses of NULL. */
6502 {
6503 source_location loc =
6510 else
6513 }
6515 /* Issue warnings if "false" is converted to a NULL pointer */
6518 {
6521 "converting %<false%> to pointer type for argument %P "
6523 else
6526 }
6527 }
6529 /* We gave a diagnostic during a conversion. If this was in the second
6530 standard conversion sequence of a user-defined conversion sequence, say
6531 which user-defined conversion. */
6533 static void
6535 {
6539 {
6543 }
6544 }
6546 /* Perform the conversions in CONVS on the expression EXPR. FN and
6547 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6548 indicates the `this' argument of a method. INNER is nonzero when
6549 being called to continue a conversion chain. It is negative when a
6550 reference binding will be applied, positive otherwise. If
6551 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6552 conversions will be emitted if appropriate. If C_CAST_P is true,
6553 this conversion is coming from a C-style cast; in that case,
6554 conversions to inaccessible bases are permitted. */
6556 static tree
6560 {
6562 diagnostic_t diag_kind;
6578 {
6582 /* Give a helpful error if this is bad because of excess braces. */
6587 {
6593 }
6595 /* Give a helpful error if this is bad because a conversion to bool
6596 from std::nullptr_t requires direct-initialization. */
6604 {
6606 {
6609 totype);
6615 complain);
6619 complain);
6620 else
6626 }
6628 {
6632 complain);
6634 }
6639 complain);
6642 }
6651 }
6657 {
6659 {
6663 /* When converting from an init list we consider explicit
6664 constructors, but actually trying to call one is an error. */
6667 /* Unless this is for direct-list-initialization. */
6669 /* And in C++98 a default constructor can't be explicit. */
6671 {
6677 {
6683 }
6684 else
6687 }
6689 /* If we're initializing from {}, it's value-initialization. */
6693 {
6698 {
6701 }
6703 }
6707 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6708 any more UDCs. */
6710 complain);
6712 /* If this is a constructor or a function returning an aggr type,
6713 we need to build up a TARGET_EXPR. */
6715 {
6718 /* Remember that this was list-initialization. */
6721 }
6724 }
6727 {
6733 else
6735 }
6740 /* Convert a constant to its underlying value, unless we are
6741 about to bind it to a reference, in which case we need to
6742 leave it as an lvalue. */
6744 {
6747 /* If __null has been converted to an integer type, we do not
6748 want to warn about uses of EXPR as an integer, rather than
6749 as a pointer. */
6751 }
6754 /* We leave bad_p off ck_ambig because overload resolution considers
6755 it valid, it just fails when we try to perform it. So we need to
6756 check complain here, too. */
6758 {
6759 /* Call build_user_type_conversion again for the error. */
6761 complain);
6765 }
6769 {
6770 /* Conversion to std::initializer_list<T>. */
6778 /* Convert all the elements. */
6780 {
6791 }
6792 /* Build up the array. */
6793 elttype = cp_build_qualified_type
6797 /* Take the address explicitly rather than via decay_conversion
6798 to avoid the error about taking the address of a temporary. */
6804 /* Build up the initializer_list object. */
6812 }
6816 {
6825 }
6828 complain);
6835 };
6840 c_cast_p,
6841 complain);
6846 {
6850 {
6852 {
6857 }
6859 }
6864 /* Don't introduce copies when passing arguments along to the inherited
6865 constructor. */
6867 && flag_new_inheriting_ctors
6871 /* Fall through. */
6874 {
6875 /* We are going to bind a reference directly to a base-class
6876 subobject of EXPR. */
6877 /* Build an expression for `*((base*) &expr)'. */
6881 }
6883 /* Copy-initialization where the cv-unqualified version of the source
6884 type is the same class as, or a derived class of, the class of the
6885 destination [is treated as direct-initialization]. [dcl.init] */
6888 /* This conversion is being done in the context of a user-defined
6889 conversion (i.e. the second step of copy-initialization), so
6890 don't allow any more. */
6892 else
6898 /* Copy-list-initialization doesn't actually involve a copy. */
6902 {
6907 }
6912 {
6916 {
6929 else
6936 }
6938 /* If necessary, create a temporary.
6940 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6941 that need temporaries, even when their types are reference
6942 compatible with the type of reference being bound, so the
6943 upcoming call to cp_build_addr_expr doesn't fail. */
6947 {
6948 /* Otherwise, a temporary of type "cv1 T1" is created and
6949 initialized from the initializer expression using the rules
6950 for a non-reference copy-initialization (8.5). */
6959 {
6960 /* If the reference is volatile or non-const, we
6961 cannot create a temporary. */
6968 else
6972 }
6973 /* If the source is a packed field, and we must use a copy
6974 constructor, then building the target expr will require
6975 binding the field to the reference parameter to the
6976 copy constructor, and we'll end up with an infinite
6977 loop. If we can use a bitwise copy, then we'll be
6978 OK. */
6982 {
6986 }
6988 {
6991 }
6993 }
6995 /* Take the address of the thing to which we will bind the
6996 reference. */
7001 /* Convert it to a pointer to the type referred to by the
7002 reference. This will adjust the pointer if a derived to
7003 base conversion is being performed. */
7006 /* Convert the pointer to the desired reference type. */
7008 }
7014 /* ??? Should the address of a transaction-safe pointer point to the TM
7015 clone, and this conversion look up the primary function? */
7019 /* Warn about deprecated conversion if appropriate. */
7035 }
7043 else
7047 }
7049 /* ARG is being passed to a varargs function. Perform any conversions
7050 required. Return the converted value. */
7052 tree
7054 {
7055 tree arg_type;
7058 /* [expr.call]
7060 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7061 standard conversions are performed. */
7064 /* [expr.call]
7066 If the argument has integral or enumeration type that is subject
7067 to the integral promotions (_conv.prom_), or a floating point
7068 type that is subject to the floating point promotion
7069 (_conv.fpprom_), the value of the argument is converted to the
7070 promoted type before the call. */
7075 {
7079 "implicit conversion from %qT to %qT when passing "
7083 }
7087 {
7089 {
7091 complain);
7101 }
7102 else
7104 }
7110 /* In a template (or ill-formed code), we can have an incomplete type
7111 even after require_complete_type_sfinae, in which case we don't know
7112 whether it has trivial copy or not. */
7114 {
7115 /* Build up a real lvalue-to-rvalue conversion in case the
7116 copy constructor is trivial but not callable. */
7120 /* [expr.call] 5.2.2/7:
7121 Passing a potentially-evaluated argument of class type (Clause 9)
7122 with a non-trivial copy constructor or a non-trivial destructor
7123 with no corresponding parameter is conditionally-supported, with
7124 implementation-defined semantics.
7126 We support it as pass-by-invisible-reference, just like a normal
7127 value parameter.
7129 If the call appears in the context of a sizeof expression,
7130 it is not potentially-evaluated. */
7134 {
7137 "passing objects of non-trivially-copyable "
7139 arg_type);
7141 }
7142 }
7145 }
7147 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7149 tree
7151 {
7153 {
7157 }
7167 {
7170 }
7174 {
7175 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7176 it as pass by invisible reference. */
7178 "receiving objects of non-trivially-copyable type %q#T "
7184 }
7188 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7189 know how to handle it. */
7192 }
7194 /* TYPE has been given to va_arg. Apply the default conversions which
7195 would have happened when passed via ellipsis. Return the promoted
7196 type, or the passed type if there is no change. */
7198 tree
7200 {
7201 tree promote;
7203 /* Perform the array-to-pointer and function-to-pointer
7204 conversions. */
7212 }
7214 /* ARG is a default argument expression being passed to a parameter of
7215 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7216 zero-based argument number. Do any required conversions. Return
7217 the converted value. */
7220 void
7224 void
7228 tree
7230 tsubst_flags_t complain)
7231 {
7233 tree t;
7235 /* See through clones. */
7237 /* And inheriting ctors. */
7241 /* Detect recursion. */
7244 {
7248 }
7250 /* If the ARG is an unparsed default argument expression, the
7251 conversion cannot be performed. */
7253 {
7258 }
7265 /* Due to:
7267 [dcl.fct.default]
7269 The names in the expression are bound, and the semantic
7270 constraints are checked, at the point where the default
7271 expressions appears.
7273 we must not perform access checks here. */
7275 /* We must make a copy of ARG, in case subsequent processing
7276 alters any part of it. */
7280 complain);
7287 }
7289 /* Returns the type which will really be used for passing an argument of
7290 type TYPE. */
7292 tree
7294 {
7295 /* Pass classes with copy ctors by invisible reference. */
7297 {
7299 /* There are no other pointers to this temporary. */
7301 }
7309 }
7311 /* Actually perform the appropriate conversion. */
7313 tree
7315 {
7316 tree bitfield_type;
7318 /* If VAL is a bitfield, then -- since it has already been converted
7319 to TYPE -- it cannot have a precision greater than TYPE.
7321 If it has a smaller precision, we must widen it here. For
7322 example, passing "int f:3;" to a function expecting an "int" will
7323 not result in any conversion before this point.
7325 If the precision is the same we must not risk widening. For
7326 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7327 often have type "int", even though the C++ type for the field is
7328 "long long". If the value is being passed to a function
7329 expecting an "int", then no conversions will be required. But,
7330 if we call convert_bitfield_to_declared_type, the bitfield will
7331 be converted to "long long". */
7338 ;
7339 /* Pass classes with copy ctors by invisible reference. */
7349 {
7358 }
7360 }
7362 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7363 which just decay_conversion or no conversions at all should be done.
7364 This is true for some builtins which don't act like normal functions.
7365 Return 2 if no conversions at all should be done, 1 if just
7366 decay_conversion. Return 3 for special treatment of the 3rd argument
7367 for __builtin_*_overflow_p. */
7369 int
7371 {
7377 {
7392 }
7395 }
7397 /* Returns the decl of the dispatcher function if FN is a function version. */
7399 tree
7401 {
7411 {
7415 }
7420 }
7422 /* fn is a function version dispatcher that is marked used. Mark all the
7423 semantically identical function versions it will dispatch as used. */
7425 void
7427 {
7444 /* All semantically identical versions are chained. Traverse and mark each
7445 one of them as used. */
7448 {
7451 }
7452 }
7454 /* Build a call to "the copy constructor" for the type of A, even if it
7455 wouldn't be selected by normal overload resolution. Used for
7456 diagnostics. */
7458 static tree
7460 {
7471 }
7473 /* Return true iff T refers to a base field. */
7475 static bool
7477 {
7486 }
7488 /* We can't elide a copy from a function returning by value to a base
7489 subobject, as the callee might clobber tail padding. Return true iff this
7490 could be that case. */
7492 static bool
7494 {
7495 /* Copy elision only happens with a TARGET_EXPR. */
7499 /* It's safe to elide the copy for a class with no tail padding. */
7502 /* It's safe to elide the copy if we aren't initializing a base object. */
7506 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7511 }
7513 /* Subroutine of the various build_*_call functions. Overload resolution
7514 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7515 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7516 bitmask of various LOOKUP_* flags which apply to the call itself. */
7518 static tree
7520 {
7528 tree val;
7537 /* In a template, there is no need to perform all of the work that
7538 is normally done. We are only interested in the type of the call
7539 expression, i.e., the return type of the function. Any semantic
7540 errors will be deferred until the template is instantiated. */
7542 {
7544 tree return_type;
7552 else
7553 {
7556 tree arg;
7564 }
7574 }
7576 /* Give any warnings we noticed during overload resolution. */
7578 {
7582 }
7584 /* OK, we're actually calling this inherited constructor; set its deletedness
7585 appropriately. We can get away with doing this here because calling is
7586 the only way to refer to a constructor. */
7590 /* Make =delete work with SFINAE. */
7595 {
7596 tree access_fn;
7597 /* If FN is a template function, two cases must be considered.
7598 For example:
7600 struct A {
7601 protected:
7602 template <class T> void f();
7603 };
7604 template <class T> struct B {
7605 protected:
7606 void g();
7607 };
7608 struct C : A, B<int> {
7609 using A::f; // #1
7610 using B<int>::g; // #2
7611 };
7613 In case #1 where `A::f' is a member template, DECL_ACCESS is
7614 recorded in the primary template but not in its specialization.
7615 We check access of FN using its primary template.
7617 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7618 because it is a member of class template B, DECL_ACCESS is
7619 recorded in the specialization `B<int>::g'. We cannot use its
7620 primary template because `B<T>::g' and `B<int>::g' may have
7621 different access. */
7625 else
7630 }
7632 /* If we're checking for implicit delete, don't bother with argument
7633 conversions. */
7635 {
7637 {
7641 }
7645 /* Reject bad conversions now. */
7647 /* else continue to get conversion error. */
7648 }
7650 /* N3276 magic doesn't apply to nested calls. */
7654 /* Find maximum size of vector to hold converted arguments. */
7661 /* The implicit parameters to a constructor are not considered by overload
7662 resolution, and must be of the proper type. */
7664 {
7665 tree object_arg;
7667 {
7670 }
7671 else
7672 {
7675 }
7678 /* We should never try to call the abstract constructor. */
7682 {
7686 }
7687 }
7688 /* Bypass access control for 'this' parameter. */
7690 {
7693 ? first_arg
7696 tree converted_arg;
7697 tree base_binfo;
7700 {
7702 {
7707 }
7708 else
7710 }
7712 /* See if the function member or the whole class type is declared
7713 final and the call can be devirtualized. */
7718 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7719 X is called for an object that is not of type X, or of a type
7720 derived from X, the behavior is undefined.
7722 So we can assume that anything passed as 'this' is non-null, and
7723 optimize accordingly. */
7725 /* Convert to the base in which the function was declared. */
7728 arg,
7731 /* Check that the base class is accessible. */
7734 {
7739 else
7741 }
7742 /* If fn was found by a using declaration, the conversion path
7743 will be to the derived class, not the base declaring fn. We
7744 must convert from derived to base. */
7755 else
7759 }
7764 {
7771 /* If the argument is NULL and used to (implicitly) instantiate a
7772 template function (and bind one of the template arguments to
7773 the type of 'long int'), we don't want to warn about passing NULL
7774 to non-pointer argument.
7775 For example, if we have this template function:
7777 template<typename T> void func(T x) {}
7779 we want to warn (when -Wconversion is enabled) in this case:
7781 void foo() {
7782 func<int>(NULL);
7783 }
7785 but not in this case:
7787 void foo() {
7788 func(NULL);
7789 }
7790 */
7797 /* Warn about initializer_list deduction that isn't currently in the
7798 working draft. */
7800 && flag_deduce_init_list
7804 {
7817 {
7825 }
7826 }
7828 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7829 knows not to allow any more UDCs. This needs to happen after we
7830 process cand->warnings. */
7835 conversion_warning
7836 ? complain
7843 else
7845 }
7847 /* Default arguments */
7849 {
7855 complain);
7856 }
7858 /* Ellipsis */
7861 {
7864 {
7865 /* Do no conversions for certain magic varargs. */
7869 }
7871 /* For other magic varargs only do decay_conversion. */
7876 {
7877 /* Avoid infinite recursion trying to call A(...). */
7879 /* Try to call the actual copy constructor for a good error. */
7882 }
7883 else
7888 }
7893 /* Avoid to do argument-transformation, if warnings for format, and for
7894 nonnull are disabled. Just in case that at least one of them is active
7895 the check_function_arguments function might warn about something. */
7899 {
7907 }
7910 {
7911 /* Check for passing ellipsis arguments to an inherited constructor. We
7912 could handle this by open-coding the inherited constructor rather than
7913 defining it, but let's not bother now. */
7917 {
7919 {
7923 }
7925 }
7927 /* A base constructor inheriting from a virtual base doesn't get the
7928 inherited arguments, just this and __vtt. */
7931 }
7933 /* Avoid actually calling copy constructors and copy assignment operators,
7934 if possible. */
7941 /* It's unsafe to elide the constructor when handling
7942 a noexcept-expression, it may evaluate to the wrong
7943 value (c++/53025). */
7945 {
7946 tree targ;
7948 tree fa;
7951 /* Pull out the real argument, disregarding const-correctness. */
7957 {
7962 }
7963 else
7968 else
7971 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
7972 subobject. */
7976 /* See unsafe_copy_elision_p. */
7979 /* [class.copy]: the copy constructor is implicitly defined even if
7980 the implementation elided its use. */
7982 {
7986 }
7988 /* If we're creating a temp and we already have one, don't create a
7989 new one. If we're not creating a temp but we get one, use
7990 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7991 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7992 temp or an INIT_EXPR otherwise. */
7995 {
8000 }
8003 {
8005 RO_NULL,
8006 complain));
8010 }
8011 }
8015 {
8016 tree to = cp_stabilize_reference
8023 {
8024 /* Avoid copying empty classes. */
8027 }
8029 {
8032 }
8033 else
8034 {
8035 /* We must only copy the non-tail padding parts. */
8043 build_index_type
8052 }
8055 }
8058 {
8062 {
8065 else
8067 }
8068 }
8070 /* For calls to a multi-versioned function, overload resolution
8071 returns the function with the highest target priority, that is,
8072 the version that will checked for dispatching first. If this
8073 version is inlinable, a direct call to this version can be made
8074 otherwise the call should go through the dispatcher. */
8079 {
8085 }
8092 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8093 virtual functions can't be constexpr. */
8095 {
8096 tree t;
8103 complain);
8109 }
8110 else
8111 {
8115 }
8121 {
8123 /* build_new_op_1 will clear this when appropriate. */
8125 }
8127 {
8131 }
8133 }
8135 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8136 This function performs no overload resolution, conversion, or other
8137 high-level operations. */
8139 tree
8141 tsubst_flags_t complain)
8142 {
8143 tree fndecl;
8145 /* Remember roughly where this call is. */
8152 /* Check that arguments to builtin functions match the expectations. */
8156 {
8159 /* We need to take care that values to BUILT_IN_NORMAL
8160 are reduced. */
8167 }
8169 /* If it is a built-in array notation function, then the return type of
8170 the function is the element type of the array passed in as array
8171 notation (i.e. the first parameter of the function). */
8173 {
8182 {
8184 {
8187 }
8188 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8189 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8190 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8191 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8192 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8193 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8194 The pre-defined return-type is the correct one. */
8198 }
8199 }
8204 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8205 function call is either the operand of a decltype-specifier or the
8206 right operand of a comma operator that is the operand of a
8207 decltype-specifier, a temporary object is not introduced for the
8208 prvalue. The type of the prvalue may be incomplete. */
8210 {
8217 }
8219 }
8221 /* Returns the value to use for the in-charge parameter when making a
8222 call to a function with the indicated NAME.
8224 FIXME:Can't we find a neater way to do this mapping? */
8226 tree
8228 {
8239 /* This function should only be called with one of the names listed
8240 above. */
8243 }
8245 /* We've built up a constructor call RET. Complain if it delegates to the
8246 constructor we're currently compiling. */
8248 static void
8250 {
8256 }
8258 /* Build a call to a constructor, destructor, or an assignment
8259 operator for INSTANCE, an expression with class type. NAME
8260 indicates the special member function to call; *ARGS are the
8261 arguments. ARGS may be NULL. This may change ARGS. BINFO
8262 indicates the base of INSTANCE that is to be passed as the `this'
8263 parameter to the member function called.
8265 FLAGS are the LOOKUP_* flags to use when processing the call.
8267 If NAME indicates a complete object constructor, INSTANCE may be
8268 NULL_TREE. In this case, the caller will call build_cplus_new to
8269 store the newly constructed object into a VAR_DECL. */
8271 tree
8274 {
8275 tree fns;
8276 /* The type of the subobject to be constructed or destroyed. */
8277 tree class_type;
8279 tree ret;
8288 {
8289 /* Resolve the name. */
8294 }
8300 /* Handle the special case where INSTANCE is NULL_TREE. */
8303 else
8304 {
8310 /* Convert to the base class, if necessary. */
8313 {
8315 /* For constructors and destructors, either the base is
8316 non-virtual, or it is virtual but we are doing the
8317 conversion from a constructor or destructor for the
8318 complete object. In either case, we can convert
8319 statically. */
8321 else
8322 /* However, for assignment operators, we must convert
8323 dynamically if the base is virtual. */
8326 }
8327 }
8331 /* In C++17, "If the initializer expression is a prvalue and the
8332 cv-unqualified version of the source type is the same class as the class
8333 of the destination, the initializer expression is used to initialize the
8334 destination object." Handle that here to avoid doing overload
8335 resolution. */
8339 {
8342 /* FIXME P0135 doesn't say how to handle direct initialization from a
8343 type with a suitable conversion operator. Let's handle it like
8344 copy-initialization, but allowing explict conversions. */
8350 && (same_type_ignoring_top_level_qualifiers_p
8352 {
8358 /* Avoid change of behavior on Wunused-var-2.C. */
8361 }
8362 }
8366 /* When making a call to a constructor or destructor for a subobject
8367 that uses virtual base classes, pass down a pointer to a VTT for
8368 the subobject. */
8372 {
8373 tree vtt;
8374 tree sub_vtt;
8376 /* If the current function is a complete object constructor
8377 or destructor, then we fetch the VTT directly.
8378 Otherwise, we look it up using the VTT we were given. */
8386 else
8390 {
8393 }
8396 }
8401 complain);
8412 }
8414 /* Return the NAME, as a C string. The NAME indicates a function that
8415 is a member of TYPE. *FREE_P is set to true if the caller must
8416 free the memory returned.
8418 Rather than go through all of this, we should simply set the names
8419 of constructors and destructors appropriately, and dispense with
8420 ctor_identifier, dtor_identifier, etc. */
8424 {
8427 /* Assume that we will not allocate memory. */
8429 /* Constructors and destructors are special. */
8431 {
8432 pretty_name
8434 /* For a destructor, add the '~'. */
8438 {
8440 /* Remember that we need to free the memory allocated. */
8442 }
8443 }
8445 {
8448 TFF_PLAIN_IDENTIFIER),
8449 NULL);
8450 /* Remember that we need to free the memory allocated. */
8452 }
8453 else
8457 }
8459 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8460 be set, upon return, to the function called. ARGS may be NULL.
8461 This may change ARGS. */
8463 static tree
8467 {
8472 tree optype;
8474 tree name;
8477 tree call;
8478 tree fn;
8481 tree orig_instance;
8482 tree orig_fns;
8488 /* We don't know what function we're going to call, yet. */
8497 {
8501 }
8506 /* Dismantle the baselink to collect all the information we need. */
8514 {
8518 }
8529 {
8534 }
8537 /* Under DR 147 A::A() is an invalid constructor call,
8538 not a functional cast. */
8540 {
8550 complain);
8552 }
8554 /* Figure out whether to skip the first argument for the error
8555 message we will display to users if an error occurs. We don't
8556 want to display any compiler-generated arguments. The "this"
8557 pointer hasn't been added yet. However, we must remove the VTT
8558 pointer if this is a call to a base-class constructor or
8559 destructor. */
8562 {
8563 /* Callers should explicitly indicate whether they want to construct
8564 the complete object or just the part without virtual bases. */
8566 /* Similarly for destructors. */
8568 /* Remove the VTT pointer, if present. */
8572 }
8574 /* Process the argument list. */
8576 {
8580 }
8582 /* Consider the object argument to be used even if we end up selecting a
8583 static member function. */
8586 /* It's OK to call destructors and constructors on cv-qualified objects.
8587 Therefore, convert the INSTANCE to the unqualified type, if
8588 necessary. */
8591 {
8593 {
8597 }
8598 }
8602 /* For the overload resolution we need to find the actual `this`
8603 that would be captured if the call turns out to be to a
8604 non-static member function. Do not actually capture it at this
8605 point. */
8607 /* Constructors don't use the enclosing 'this'. */
8609 else
8612 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8615 /* The number of arguments artificial parms in ARGS; we subtract one because
8616 there's no 'this' in ARGS. */
8619 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8620 initializer, not T({ }). */
8624 {
8631 /* If the initializer list has no elements and T is a class type with
8632 a default constructor, the object is value-initialized. Handle
8633 this here so we don't need to handle it wherever we use
8634 build_special_member_call. */
8637 /* For a user-provided default constructor, use the normal
8638 mechanisms so that protected access works. */
8643 /* If BASETYPE is an aggregate, we need to do aggregate
8644 initialization. */
8646 {
8649 }
8652 {
8658 }
8660 /* Otherwise go ahead with overload resolution. */
8665 }
8666 else
8667 {
8671 }
8676 {
8678 {
8685 else
8686 {
8690 {
8693 }
8701 }
8703 }
8705 }
8706 else
8707 {
8710 {
8713 tree arglist;
8716 {
8724 else
8730 }
8732 }
8733 else
8734 {
8742 {
8743 /* This is not an error, it is runtime undefined
8744 behavior. */
8753 fn);
8754 }
8759 {
8764 {
8765 /* We captured 'this' in the current lambda now that
8766 we know we really need it. */
8768 }
8770 /* We can't tell until instantiation time whether we can use
8772 else
8773 {
8776 fn);
8778 }
8779 }
8782 {
8783 /* Optimize away vtable lookup if we know that this
8784 function can't be overridden. We need to check if
8785 the context and the type where we found fn are the same,
8786 actually FN might be defined in a different class
8787 type because of a using-declaration. In this case, we
8788 do not want to perform a non-virtual call. */
8790 && same_type_ignoring_top_level_qualifiers_p
8796 /* Now we know what function is being called. */
8799 /* Build the actual CALL_EXPR. */
8801 /* In an expression of the form `a->f()' where `f' turns
8802 out to be a static member function, `a' is
8803 none-the-less evaluated. */
8812 /* An explicit call of the form "x->~X()" has type
8813 "void". However, on platforms where destructors
8814 return "this" (i.e., those where
8815 targetm.cxx.cdtor_returns_this is true), such calls
8816 will appear to have a return value of pointer type
8817 to the low-level call machinery. We do not want to
8818 change the low-level machinery, since we want to be
8819 able to optimize "delete f()" on such platforms as
8820 "operator delete(~X(f()))" (rather than generating
8821 "t = f(), ~X(t), operator delete (t)"). */
8823 }
8824 }
8825 }
8828 {
8834 {
8837 }
8840 call = (build_min_non_dep_call_vec
8844 orig_args));
8849 }
8851 /* Free all the conversions we allocated. */
8858 }
8860 /* Wrapper for above. */
8862 tree
8866 {
8867 tree ret;
8873 }
8875 /* Returns true iff standard conversion sequence ICS1 is a proper
8876 subsequence of ICS2. */
8878 static bool
8880 {
8881 /* We can assume that a conversion of the same code
8882 between the same types indicates a subsequence since we only get
8883 here if the types we are converting from are the same. */
8890 {
8900 /* At this point, ICS1 cannot be a proper subsequence of
8901 ICS2. We can get a USER_CONV when we are comparing the
8902 second standard conversion sequence of two user conversion
8903 sequences. */
8918 }
8919 }
8921 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8922 be any _TYPE nodes. */
8924 bool
8926 {
8930 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8931 considers every class derived from itself. */
8934 }
8936 /* We build the ICS for an implicit object parameter as a pointer
8937 conversion sequence. However, such a sequence should be compared
8938 as if it were a reference conversion sequence. If ICS is the
8939 implicit conversion sequence for an implicit object parameter,
8940 modify it accordingly. */
8942 static void
8944 {
8946 {
8947 /* [over.match.funcs]
8949 For non-static member functions, the type of the
8950 implicit object parameter is "reference to cv X"
8951 where X is the class of which the function is a
8952 member and cv is the cv-qualification on the member
8953 function declaration. */
8955 tree reference_type;
8957 /* The `this' parameter is a pointer to a class type. Make the
8958 implicit conversion talk about a reference to that same class
8959 type. */
8972 }
8973 }
8975 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8976 and return the initial reference binding conversion. Otherwise,
8977 leave *ICS unchanged and return NULL. */
8981 {
8983 {
8988 }
8991 }
8993 /* Compare two implicit conversion sequences according to the rules set out in
8994 [over.ics.rank]. Return values:
8996 1: ics1 is better than ics2
8997 -1: ics2 is better than ics1
8998 0: ics1 and ics2 are indistinguishable */
9000 static int
9002 {
9003 tree from_type1;
9004 tree from_type2;
9005 tree to_type1;
9006 tree to_type2;
9013 /* REF_BINDING is nonzero if the result of the conversion sequence
9014 is a reference type. In that case REF_CONV is the reference
9015 binding conversion. */
9019 /* Compare badness before stripping the reference conversion. */
9025 /* Handle implicit object parameters. */
9029 /* Handle reference parameters. */
9033 /* List-initialization sequence L1 is a better conversion sequence than
9034 list-initialization sequence L2 if L1 converts to
9035 std::initializer_list<X> for some X and L2 does not. */
9041 /* [over.ics.rank]
9043 When comparing the basic forms of implicit conversion sequences (as
9044 defined in _over.best.ics_)
9046 --a standard conversion sequence (_over.ics.scs_) is a better
9047 conversion sequence than a user-defined conversion sequence
9048 or an ellipsis conversion sequence, and
9050 --a user-defined conversion sequence (_over.ics.user_) is a
9051 better conversion sequence than an ellipsis conversion sequence
9052 (_over.ics.ellipsis_). */
9053 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9054 mismatch. If both ICS are bad, we try to make a decision based on
9055 what would have happened if they'd been good. This is not an
9056 extension, we'll still give an error when we build up the call; this
9057 just helps us give a more helpful error message. */
9067 /* Both conversions are ellipsis conversions. */
9070 /* User-defined conversion sequence U1 is a better conversion sequence
9071 than another user-defined conversion sequence U2 if they contain the
9072 same user-defined conversion operator or constructor and if the sec-
9073 ond standard conversion sequence of U1 is better than the second
9074 standard conversion sequence of U2. */
9076 /* Handle list-conversion with the same code even though it isn't always
9077 ranked as a user-defined conversion and it doesn't have a second
9078 standard conversion sequence; it will still have the desired effect.
9079 Specifically, we need to do the reference binding comparison at the
9080 end of this function. */
9083 {
9099 {
9102 }
9103 else
9104 {
9105 /* For ambiguous or aggregate conversions, use the target type as
9106 a proxy for the conversion function. */
9109 }
9111 /* We can just fall through here, after setting up
9112 FROM_TYPE1 and FROM_TYPE2. */
9115 }
9116 else
9117 {
9121 /* We're dealing with two standard conversion sequences.
9123 [over.ics.rank]
9125 Standard conversion sequence S1 is a better conversion
9126 sequence than standard conversion sequence S2 if
9128 --S1 is a proper subsequence of S2 (comparing the conversion
9129 sequences in the canonical form defined by _over.ics.scs_,
9130 excluding any Lvalue Transformation; the identity
9131 conversion sequence is considered to be a subsequence of
9132 any non-identity conversion sequence */
9143 }
9145 /* One sequence can only be a subsequence of the other if they start with
9146 the same type. They can start with different types when comparing the
9147 second standard conversion sequence in two user-defined conversion
9148 sequences. */
9150 {
9155 }
9157 /* [over.ics.rank]
9159 Or, if not that,
9161 --the rank of S1 is better than the rank of S2 (by the rules
9162 defined below):
9164 Standard conversion sequences are ordered by their ranks: an Exact
9165 Match is a better conversion than a Promotion, which is a better
9166 conversion than a Conversion.
9168 Two conversion sequences with the same rank are indistinguishable
9169 unless one of the following rules applies:
9171 --A conversion that does not a convert a pointer, pointer to member,
9172 or std::nullptr_t to bool is better than one that does.
9174 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9175 so that we do not have to check it explicitly. */
9184 /* A conversion from scalar arithmetic type to complex is worse than a
9185 conversion between scalar arithmetic types. */
9192 {
9195 else
9197 }
9203 {
9208 }
9209 /* The rules for pointers to members A::* are just like the rules
9210 for pointers A*, except opposite: if B is derived from A then
9211 A::* converts to B::*, not vice versa. For that reason, we
9212 switch the from_ and to_ variables here. */
9219 {
9224 }
9229 {
9230 /* This was one of the pointer or pointer-like conversions.
9232 [over.ics.rank]
9234 --If class B is derived directly or indirectly from class A,
9235 conversion of B* to A* is better than conversion of B* to
9236 void*, and conversion of A* to void* is better than
9237 conversion of B* to void*. */
9240 {
9242 deref_from_type2))
9245 deref_from_type1))
9247 }
9250 {
9252 {
9254 {
9256 deref_to_type1))
9258 }
9259 /* We know that DEREF_TO_TYPE1 is `void' here. */
9261 deref_to_type2))
9263 }
9264 }
9267 {
9268 /* [over.ics.rank]
9270 --If class B is derived directly or indirectly from class A
9271 and class C is derived directly or indirectly from B,
9273 --conversion of C* to B* is better than conversion of C* to
9274 A*,
9276 --conversion of B* to A* is better than conversion of C* to
9277 A* */
9279 {
9281 deref_to_type2))
9284 deref_to_type1))
9286 }
9288 {
9290 deref_from_type1))
9293 deref_from_type2))
9295 }
9296 }
9297 }
9300 {
9303 /* [over.ics.rank]
9305 --binding of an expression of type C to a reference of type
9306 B& is better than binding an expression of type C to a
9307 reference of type A&
9309 --conversion of C to B is better than conversion of C to A, */
9312 {
9317 }
9318 }
9321 {
9324 /* [over.ics.rank]
9326 --binding of an expression of type B to a reference of type
9327 A& is better than binding an expression of type C to a
9328 reference of type A&,
9330 --conversion of B to A is better than conversion of C to A */
9333 {
9338 }
9339 }
9341 /* [over.ics.rank]
9343 --S1 and S2 differ only in their qualification conversion and yield
9344 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9345 qualification signature of type T1 is a proper subset of the cv-
9346 qualification signature of type T2 */
9350 {
9354 }
9356 /* [over.ics.rank]
9358 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9359 to an implicit object parameter of a non-static member function
9360 declared without a ref-qualifier, and either S1 binds an lvalue
9361 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9362 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9363 draft standard, 13.3.3.2)
9365 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9366 types to which the references refer are the same type except for
9367 top-level cv-qualifiers, and the type to which the reference
9368 initialized by S2 refers is more cv-qualified than the type to
9369 which the reference initialized by S1 refers.
9371 DR 1328 [over.match.best]: the context is an initialization by
9372 conversion function for direct reference binding (13.3.1.6) of a
9373 reference to function type, the return type of F1 is the same kind of
9374 reference (i.e. lvalue or rvalue) as the reference being initialized,
9375 and the return type of F2 is not. */
9378 {
9385 {
9389 /* Don't prefer a bad conversion that drops cv-quals to a bad
9390 conversion with the wrong rvalueness. */
9394 }
9397 {
9401 {
9402 /* Prefer the one that drops fewer cv-quals. */
9407 }
9409 }
9410 }
9412 /* Neither conversion sequence is better than the other. */
9414 }
9416 /* The source type for this standard conversion sequence. */
9418 static tree
9420 {
9422 {
9427 }
9429 }
9431 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9432 a pointer to LOSER and re-running joust to produce the warning if WINNER
9433 is actually used. */
9435 static void
9437 {
9443 }
9445 /* Compare two candidates for overloading as described in
9446 [over.match.best]. Return values:
9448 1: cand1 is better than cand2
9449 -1: cand2 is better than cand1
9450 0: cand1 and cand2 are indistinguishable */
9452 static int
9454 tsubst_flags_t complain)
9455 {
9461 /* Candidates that involve bad conversions are always worse than those
9462 that don't. */
9468 /* If we have two pseudo-candidates for conversions to the same type,
9469 or two candidates for the same function, arbitrarily pick one. */
9474 /* Prefer a non-deleted function over an implicitly deleted move
9475 constructor or assignment operator. This differs slightly from the
9476 wording for issue 1402 (which says the move op is ignored by overload
9477 resolution), but this way produces better error messages. */
9481 {
9488 }
9490 /* a viable function F1
9491 is defined to be a better function than another viable function F2 if
9492 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9493 ICSi(F2), and then */
9495 /* for some argument j, ICSj(F1) is a better conversion sequence than
9496 ICSj(F2) */
9498 /* For comparing static and non-static member functions, we ignore
9499 the implicit object parameter of the non-static function. The
9500 standard says to pretend that the static function has an object
9501 parm, but that won't work with operator overloading. */
9504 {
9510 /* We're comparing a near-match list constructor and a near-match
9511 non-list constructor. Just treat them as unordered. */
9518 else
9519 {
9522 }
9523 }
9526 {
9532 {
9534 && warn_sign_promo
9546 {
9553 else
9558 {
9562 }
9563 else
9565 }
9568 {
9571 }
9573 }
9574 }
9576 /* warn about confusing overload resolution for user-defined conversions,
9577 either between a constructor and a conversion op, or between two
9578 conversion ops. */
9583 {
9589 else
9592 /* We don't want to complain about `X::operator T1 ()'
9593 beating `X::operator T2 () const', when T2 is a no less
9594 cv-qualified version of T1. */
9597 {
9602 {
9605 }
9608 }
9609 else
9615 {
9622 {
9624 }
9625 }
9626 else
9628 }
9633 /* DR 495 moved this tiebreaker above the template ones. */
9634 /* or, if not that,
9635 the context is an initialization by user-defined conversion (see
9636 _dcl.init_ and _over.match.user_) and the standard conversion
9637 sequence from the return type of F1 to the destination type (i.e.,
9638 the type of the entity being initialized) is a better conversion
9639 sequence than the standard conversion sequence from the return type
9640 of F2 to the destination type. */
9643 {
9647 }
9649 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
9651 {
9653 /* We distinguish between candidates from an explicit deduction guide and
9654 candidates built from a constructor based on DECL_ARTIFICIAL. */
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 /* or, if not that, F2 is from a using-declaration, F1 is not, and the
9699 conversion sequences are equivalent.
9700 (proposed in http://lists.isocpp.org/core/2016/10/1142.php) */
9705 {
9713 {
9715 {
9720 }
9723 }
9724 }
9726 /* Check whether we can discard a builtin candidate, either because we
9727 have two identical ones or matching builtin and non-builtin candidates.
9729 (Pedantically in the latter case the builtin which matched the user
9730 function should not be added to the overload set, but we spot it here.
9732 [over.match.oper]
9733 ... the builtin candidates include ...
9734 - do not have the same parameter type list as any non-template
9735 non-member candidate. */
9738 {
9744 {
9746 /* Two built-in candidates; arbitrarily pick one. */
9749 /* cand1 is built-in; prefer cand2. */
9751 else
9752 /* cand2 is built-in; prefer cand1. */
9754 }
9755 }
9757 /* For candidates of a multi-versioned function, make the version with
9758 the highest priority win. This version will be checked for dispatching
9759 first. If this version can be inlined into the caller, the front-end
9760 will simply make a direct call to this function. */
9766 {
9772 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9773 is possible that cand1->fn and cand2->fn are function versions but of
9774 different functions. Check types to see if they are versions of the same
9775 function. */
9778 {
9779 /* Always make the version with the higher priority, more
9780 specialized, win. */
9784 else
9786 }
9787 }
9789 /* If the two function declarations represent the same function (this can
9790 happen with declarations in multiple scopes and arg-dependent lookup),
9791 arbitrarily choose one. But first make sure the default args we're
9792 using match. */
9795 {
9802 {
9803 /* Don't crash if the fn is variadic. */
9808 }
9816 {
9819 {
9821 {
9823 {
9825 "default argument mismatch in "
9827 {
9832 }
9833 }
9834 else
9836 }
9837 else
9840 }
9843 }
9846 }
9848 tweak:
9850 /* Extension: If the worst conversion for one candidate is worse than the
9851 worst conversion for the other, take the first. */
9853 {
9858 {
9863 }
9869 {
9870 /* Don't choose a deleted function over ambiguity. */
9874 {
9876 "ISO C++ says that these are ambiguous, even "
9877 "though the worst conversion for the first is better than "
9881 }
9882 else
9885 }
9886 }
9890 }
9892 /* Given a list of candidates for overloading, find the best one, if any.
9893 This algorithm has a worst case of O(2n) (winner is last), and a best
9894 case of O(n/2) (totally ambiguous); much better than a sorting
9895 algorithm. */
9899 {
9904 /* Walk through the list once, comparing each current champ to the next
9905 candidate, knocking out a candidate or two with each comparison. */
9908 {
9912 else
9913 {
9915 {
9920 }
9921 else
9922 {
9925 }
9928 }
9929 }
9931 /* Make sure the champ is better than all the candidates it hasn't yet
9932 been compared to. */
9935 challenger != champ
9938 {
9942 }
9945 }
9947 /* Returns nonzero if things of type FROM can be converted to TO. */
9949 bool
9951 {
9953 /* implicit_conversion only considers user-defined conversions
9954 if it has an expression for the call argument list. */
9958 }
9960 /* Returns nonzero if things of type FROM can be converted to TO with a
9961 standard conversion. */
9963 bool
9965 {
9967 }
9969 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9971 bool
9973 tsubst_flags_t complain)
9974 {
9979 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9981 /* We want to discard any access checks done for this test,
9982 as we might not be in the appropriate access context and
9983 we'll do the check again when we actually perform the
9984 conversion. */
9991 /* Discard the access checks now. */
9993 /* Free all the conversions we allocated. */
9997 }
9999 /* Like can_convert_arg, but allows dubious conversions as well. */
10001 bool
10003 tsubst_flags_t complain)
10004 {
10008 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10010 /* Try to perform the conversion. */
10013 /* Free all the conversions we allocated. */
10017 }
10019 /* Convert EXPR to TYPE. Return the converted expression.
10021 Note that we allow bad conversions here because by the time we get to
10022 this point we are committed to doing the conversion. If we end up
10023 doing a bad conversion, convert_like will complain. */
10025 tree
10028 {
10036 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10044 {
10046 {
10047 /* If expr has unknown type, then it is an overloaded function.
10048 Call instantiate_type to get good error messages. */
10053 else
10056 }
10058 }
10060 {
10061 /* In a template, we are only concerned about determining the
10062 type of non-dependent expressions, so we do not have to
10063 perform the actual conversion. But for initializers, we
10064 need to be able to perform it at instantiation
10065 (or instantiate_non_dependent_expr) time. */
10069 }
10070 else
10073 /* Free all the conversions we allocated. */
10077 }
10079 tree
10081 {
10083 LOOKUP_IMPLICIT);
10084 }
10086 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10087 permitted. If the conversion is valid, the converted expression is
10088 returned. Otherwise, NULL_TREE is returned, except in the case
10089 that TYPE is a class type; in that case, an error is issued. If
10090 C_CAST_P is true, then this direct-initialization is taking
10091 place as part of a static_cast being attempted as part of a C-style
10092 cast. */
10094 tree
10096 tree expr,
10098 tsubst_flags_t complain)
10099 {
10105 /* [dcl.init]
10107 If the destination type is a (possibly cv-qualified) class type:
10109 -- If the initialization is direct-initialization ...,
10110 constructors are considered. ... If no constructor applies, or
10111 the overload resolution is ambiguous, the initialization is
10112 ill-formed. */
10114 {
10120 }
10122 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10126 c_cast_p,
10130 else
10133 c_cast_p,
10134 complain);
10136 /* Free all the conversions we allocated. */
10140 }
10142 /* When initializing a reference that lasts longer than a full-expression,
10143 this special rule applies:
10145 [class.temporary]
10147 The temporary to which the reference is bound or the temporary
10148 that is the complete object to which the reference is bound
10149 persists for the lifetime of the reference.
10151 The temporaries created during the evaluation of the expression
10152 initializing the reference, except the temporary to which the
10153 reference is bound, are destroyed at the end of the
10154 full-expression in which they are created.
10156 In that case, we store the converted expression into a new
10157 VAR_DECL in a new scope.
10159 However, we want to be careful not to create temporaries when
10160 they are not required. For example, given:
10162 struct B {};
10163 struct D : public B {};
10164 D f();
10165 const B& b = f();
10167 there is no need to copy the return value from "f"; we can just
10168 extend its lifetime. Similarly, given:
10170 struct S {};
10171 struct T { operator S(); };
10172 T t;
10173 const S& s = t;
10175 we can extend the lifetime of the return value of the conversion
10176 operator.
10178 The next several functions are involved in this lifetime extension. */
10180 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10181 reference is being bound to a temporary. Create and return a new
10182 VAR_DECL with the indicated TYPE; this variable will store the value to
10183 which the reference is bound. */
10185 tree
10187 {
10188 tree var;
10190 /* Create the variable. */
10193 /* Register the variable. */
10196 {
10197 /* Namespace-scope or local static; give it a mangled name. */
10198 /* FIXME share comdat with decl? */
10199 tree name;
10208 }
10209 else
10210 /* Create a new cleanup level if necessary. */
10214 }
10216 /* EXPR is the initializer for a variable DECL of reference or
10217 std::initializer_list type. Create, push and return a new VAR_DECL
10218 for the initializer so that it will live as long as DECL. Any
10219 cleanup for the new variable is returned through CLEANUP, and the
10220 code to initialize the new variable is returned through INITP. */
10222 static tree
10225 {
10226 tree init;
10227 tree type;
10228 tree var;
10230 /* Create the temporary variable. */
10234 /* If the rvalue is the result of a function call it will be
10235 a TARGET_EXPR. If it is some other construct (such as a
10236 member access expression where the underlying object is
10237 itself the result of a function call), turn it into a
10238 TARGET_EXPR here. It is important that EXPR be a
10239 TARGET_EXPR below since otherwise the INIT_EXPR will
10240 attempt to make a bitwise copy of EXPR to initialize
10241 VAR. */
10247 {
10251 }
10253 /* Recursively extend temps in this initializer. */
10257 /* Any reference temp has a non-trivial initializer. */
10260 /* If the initializer is constant, put it in DECL_INITIAL so we get
10261 static initialization and use in constant expressions. */
10264 {
10266 {
10267 /* 5.19 says that a constant expression can include an
10268 lvalue-rvalue conversion applied to "a glvalue of literal type
10269 that refers to a non-volatile temporary object initialized
10270 with a constant expression". Rather than try to communicate
10271 that this VAR_DECL is a temporary, just mark it constexpr.
10273 Currently this is only useful for initializer_list temporaries,
10274 since reference vars can't appear in constant expressions. */
10278 }
10281 }
10282 else
10283 /* Create the INIT_EXPR that will initialize the temporary
10284 variable. */
10287 {
10292 else
10293 {
10297 }
10299 /* We must be careful to destroy the temporary only
10300 after its initialization has taken place. If the
10301 initialization throws an exception, then the
10302 destructor should not be run. We cannot simply
10303 transform INIT into something like:
10305 (INIT, ({ CLEANUP_STMT; }))
10307 because emit_local_var always treats the
10308 initializer as a full-expression. Thus, the
10309 destructor would run too early; it would run at the
10310 end of initializing the reference variable, rather
10311 than at the end of the block enclosing the
10312 reference variable.
10314 The solution is to pass back a cleanup expression
10315 which the caller is responsible for attaching to
10316 the statement tree. */
10317 }
10318 else
10319 {
10322 {
10325 tls_aggregates);
10326 else
10328 static_aggregates);
10329 }
10330 else
10331 /* Check whether the dtor is callable. */
10333 }
10334 /* Avoid -Wunused-variable warning (c++/38958). */
10341 }
10343 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10344 initializing a variable of that TYPE. */
10346 tree
10349 {
10357 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10363 {
10365 {
10374 else
10378 }
10380 }
10383 /* Perform the conversion. */
10386 /* We gave an error in build_user_type_conversion_1. */
10388 else
10391 /* Free all the conversions we allocated. */
10395 }
10397 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10398 which is bound either to a reference or a std::initializer_list. */
10400 static tree
10402 {
10407 {
10411 }
10414 /* Deal with binding to a subobject. */
10418 {
10426 }
10428 }
10430 /* INIT is part of the initializer for DECL. If there are any
10431 reference or initializer lists being initialized, extend their
10432 lifetime to match that of DECL. */
10434 tree
10436 {
10442 else
10443 {
10448 {
10450 {
10451 /* The temporary array underlying a std::initializer_list
10452 is handled like a reference temporary. */
10456 }
10457 else
10458 {
10464 }
10465 }
10466 }
10469 }
10471 /* Returns true iff an initializer for TYPE could contain temporaries that
10472 need to be extended because they are bound to references or
10473 std::initializer_list. */
10475 bool
10477 {
10482 {
10489 }
10491 }
10493 /* Returns true iff TYPE is some variant of std::initializer_list. */
10495 bool
10497 {
10498 /* Look through typedefs. */
10507 }
10509 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10510 will accept an argument list of a single std::initializer_list<T>. */
10512 bool
10514 {
10516 tree arg;
10528 /* There are more non-defaulted parms. */
10532 }