| blob | fac6b6c16ac2cbfe9c0730b44def2c2f005c999e |
1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) and
4 modified by Brendan Kehoe (brendan@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
23 /* High-level class interface. */
43 /* The various kinds of conversion. */
46 ck_identity,
47 ck_lvalue,
48 ck_fnptr,
49 ck_qual,
50 ck_std,
51 ck_ptr,
52 ck_pmem,
53 ck_base,
54 ck_ref_bind,
55 ck_user,
56 ck_ambig,
57 ck_list,
58 ck_aggr,
59 ck_rvalue
60 };
62 /* The rank of the conversion. Order of the enumerals matters; better
63 conversions should come earlier in the list. */
66 cr_identity,
67 cr_exact,
68 cr_promotion,
69 cr_std,
70 cr_pbool,
71 cr_user,
72 cr_ellipsis,
73 cr_bad
74 };
76 /* An implicit conversion sequence, in the sense of [over.best.ics].
77 The first conversion to be performed is at the end of the chain.
78 That conversion is always a cr_identity conversion. */
81 /* The kind of conversion represented by this step. */
82 conversion_kind kind;
83 /* The rank of this conversion. */
84 conversion_rank rank;
88 /* True if this conversion would be permitted with a bending of
89 language standards, e.g. disregarding pointer qualifiers or
90 converting integers to pointers. */
92 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
93 temporary should be created to hold the result of the
94 conversion. */
96 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
97 from a pointer-to-derived to pointer-to-base is being performed. */
99 /* If KIND is ck_ref_bind, true when either an lvalue reference is
100 being bound to an lvalue expression or an rvalue reference is
101 being bound to an rvalue expression. If KIND is ck_rvalue,
102 true when we should treat an lvalue as an rvalue (12.8p33). If
103 KIND is ck_base, always false. */
106 /* The type of the expression resulting from the conversion. */
107 tree type;
109 /* The next conversion in the chain. Since the conversions are
110 arranged from outermost to innermost, the NEXT conversion will
111 actually be performed before this conversion. This variant is
112 used only when KIND is neither ck_identity, ck_ambig nor
113 ck_list. Please use the next_conversion function instead
114 of using this field directly. */
116 /* The expression at the beginning of the conversion chain. This
117 variant is used only if KIND is ck_identity or ck_ambig. */
118 tree expr;
119 /* The array of conversions for an initializer_list, so this
120 variant is used only when KIN D is ck_list. */
123 /* The function candidate corresponding to this conversion
124 sequence. This field is only used if KIND is ck_user. */
126 };
128 #define CONVERSION_RANK(NODE) \
129 ((NODE)->bad_p ? cr_bad \
130 : (NODE)->ellipsis_p ? cr_ellipsis \
131 : (NODE)->user_conv_p ? cr_user \
132 : (NODE)->rank)
134 #define BAD_CONVERSION_RANK(NODE) \
135 ((NODE)->ellipsis_p ? cr_ellipsis \
136 : (NODE)->user_conv_p ? cr_user \
137 : (NODE)->rank)
146 tsubst_flags_t);
149 #define convert_like(CONV, EXPR, COMPLAIN) \
150 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, \
153 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
154 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), \
162 tsubst_flags_t);
174 static void add_builtin_candidates
177 static void add_builtin_candidate
181 static void build_builtin_candidate
191 tsubst_flags_t);
193 tsubst_flags_t);
213 tsubst_flags_t);
217 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
218 NAME can take many forms... */
220 bool
222 {
223 /* Just accept something we've already complained about. */
232 {
237 else
239 }
240 else
241 {
242 /* In the case of:
244 template <class T> struct S { ~S(); };
245 int i;
246 i.~S();
248 NAME will be a class template. */
251 }
256 }
258 /* We want the address of a function or method. We avoid creating a
259 pointer-to-member function. */
261 tree
263 {
266 /* We have to do these by hand to avoid real pointer to member
267 functions. */
269 {
271 {
275 complain);
276 }
278 }
279 else
283 }
285 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
286 POINTER_TYPE to those. Note, pointer to member function types
287 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
288 two variants. build_call_a is the primitive taking an array of
289 arguments, while build_call_n is a wrapper that handles varargs. */
291 tree
293 {
296 else
297 {
307 }
308 }
310 /* Update various flags in cfun and the call itself based on what is being
311 called. Split out of build_call_a so that bot_manip can use it too. */
313 void
315 {
319 /* We check both the decl and the type; a function may be known not to
320 throw without being declared throw(). */
334 }
336 tree
338 {
339 tree decl;
340 tree result_type;
341 tree fntype;
351 /* An rvalue has no cv-qualifiers. */
362 {
363 /* We invoke build_call directly for several library
364 functions. These may have been declared normally if
365 we're building libgcc, so we can't just check
366 DECL_ARTIFICIAL. */
371 }
378 && flag_new_inheriting_ctors
382 /* Pass arguments directly to the inherited constructor. */
385 /* Don't pass empty class objects by value. This is useful
386 for tags in STL, which are used to control overload resolution.
387 We don't need to handle other cases of copying empty classes. */
390 {
394 {
398 }
399 }
402 }
404 /* New overloading code. */
411 };
413 /* Information for providing diagnostics about why overloading failed. */
416 rr_none,
417 rr_arity,
418 rr_explicit_conversion,
419 rr_template_conversion,
420 rr_arg_conversion,
421 rr_bad_arg_conversion,
422 rr_template_unification,
423 rr_invalid_copy,
424 rr_inherited_ctor,
425 rr_constraint_failure
426 };
429 /* The index of the argument, 0-based. */
431 /* The actual argument or its type. */
432 tree from;
433 /* The type of the parameter. */
434 tree to_type;
435 };
440 /* Information about an arity mismatch. */
442 /* The expected number of arguments. */
444 /* The actual number of arguments in the call. */
446 /* Whether the call was a varargs call. */
449 /* Information about an argument conversion mismatch. */
451 /* Same, but for bad argument conversions. */
453 /* Information about template unification failures. These are the
454 parameters passed to fn_type_unification. */
456 tree tmpl;
457 tree explicit_targs;
461 tree return_type;
462 unification_kind_t strict;
465 /* Information about template instantiation failures. These are the
466 parameters passed to instantiate_template. */
468 tree tmpl;
469 tree targs;
472 };
475 /* The FUNCTION_DECL that will be called if this candidate is
476 selected by overload resolution. */
477 tree fn;
478 /* If not NULL_TREE, the first argument to use when calling this
479 function. */
480 tree first_arg;
481 /* The rest of the arguments to use when calling this function. If
482 there are no further arguments this may be NULL or it may be an
483 empty vector. */
485 /* The implicit conversion sequences for each of the arguments to
486 FN. */
488 /* The number of implicit conversion sequences. */
490 /* If FN is a user-defined conversion, the standard conversion
491 sequence from the type returned by FN to the desired destination
492 type. */
495 /* If FN is a member function, the binfo indicating the path used to
496 qualify the name of FN at the call site. This path is used to
497 determine whether or not FN is accessible if it is selected by
498 overload resolution. The DECL_CONTEXT of FN will always be a
499 (possibly improper) base of this binfo. */
500 tree access_path;
501 /* If FN is a non-static member function, the binfo indicating the
502 subobject to which the `this' pointer should be converted if FN
503 is selected by overload resolution. The type pointed to by
504 the `this' pointer must correspond to the most derived class
505 indicated by the CONVERSION_PATH. */
506 tree conversion_path;
507 tree template_decl;
508 tree explicit_targs;
513 /* The flags active in add_candidate. */
515 };
517 /* Returns true iff T is a null pointer constant in the sense of
518 [conv.ptr]. */
520 bool
522 {
525 /* [conv.ptr]
527 A null pointer constant is an integral constant expression
528 (_expr.const_) rvalue of integer type that evaluates to zero or
529 an rvalue of type std::nullptr_t. */
534 {
535 /* Core issue 903 says only literal 0 is a null pointer constant. */
542 }
544 {
549 }
552 }
554 /* Returns true iff T is a null member pointer value (4.11). */
556 bool
558 {
567 else
569 }
571 /* Returns nonzero if PARMLIST consists of only default parms,
572 ellipsis, and/or undeduced parameter packs. */
574 bool
576 {
583 }
585 /* Allocate N bytes of memory from the conversion obstack. The memory
586 is zeroed before being returned. */
590 {
593 {
596 }
600 }
602 /* Allocate rejection reasons. */
606 {
611 }
615 {
621 }
625 {
632 }
636 {
643 }
647 {
653 }
657 {
663 }
670 {
677 /* Copy args to our own storage. */
685 }
689 {
691 }
695 {
698 }
702 {
705 }
707 // Build a constraint failure record, saving information into the
708 // template_instantiation field of the rejection. If FN is not a template
709 // declaration, the TMPL member is the FN declaration and TARGS is empty.
713 {
716 {
719 }
720 else
721 {
724 }
726 }
728 /* Dynamically allocate a conversion. */
732 {
737 }
739 /* Make sure that all memory on the conversion obstack has been
740 freed. */
742 void
744 {
748 }
750 /* Dynamically allocate an array of N conversions. */
754 {
756 }
760 {
764 /* Note that the caller is responsible for filling in t->cand for
765 user-defined conversions. */
771 {
788 }
794 }
796 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
797 specialization of std::initializer_list<T>, if such a conversion is
798 possible. */
802 {
808 tree val;
810 /* Within a list-initialization we can have more user-defined
811 conversions. */
813 /* But no narrowing conversions. */
816 /* Can't make an array of these types. */
823 {
824 conversion *sub
831 }
839 {
847 }
850 }
852 /* Return the next conversion of the conversion chain (if applicable),
853 or NULL otherwise. Please use this function instead of directly
854 accessing fields of struct conversion. */
858 {
865 }
867 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
868 is a valid aggregate initializer for array type ATYPE. */
870 static bool
872 {
876 {
882 else
884 complain);
887 }
889 }
891 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
892 aggregate class, if such a conversion is possible. */
896 {
902 /* We already called reshape_init in implicit_conversion. */
904 /* The conversions within the init-list aren't affected by the enclosing
905 context; they're always simple copy-initialization. */
909 {
911 tree val;
919 /* Value-initialization of reference is ill-formed. */
921 else
922 {
926 }
932 else
934 complain);
941 }
953 }
955 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
956 array type, if such a conversion is possible. */
960 {
965 tree val;
970 /* We might need to propagate the size from the element to the array. */
975 {
979 }
984 {
985 conversion *sub
997 }
1006 }
1008 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1009 complex type, if such a conversion is possible. */
1013 tsubst_flags_t complain)
1014 {
1019 tree val;
1030 {
1031 conversion *sub
1043 }
1052 }
1054 /* Build a representation of the identity conversion from EXPR to
1055 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1059 {
1067 }
1069 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1070 were multiple user-defined conversions to accomplish the job.
1071 Build a conversion that indicates that ambiguity. */
1075 {
1083 }
1085 tree
1087 {
1091 }
1093 /* Returns the standard conversion path (see [conv]) from type FROM to type
1094 TO, if any. For proper handling of null pointer constants, you must
1095 also pass the expression EXPR to convert from. If C_CAST_P is true,
1096 this conversion is coming from a C-style cast. */
1101 {
1105 tree qualified_to;
1109 {
1112 }
1118 {
1120 {
1126 }
1128 {
1129 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1132 }
1133 }
1140 {
1144 }
1145 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1146 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1147 express the copy constructor call required by copy-initialization. */
1149 {
1151 {
1152 tree bitfield_type;
1155 {
1158 }
1159 }
1163 }
1165 /* Allow conversion between `__complex__' data types. */
1167 {
1168 /* The standard conversion sequence to convert FROM to TO is
1169 the standard conversion sequence to perform componentwise
1170 conversion. */
1173 complain);
1176 {
1179 }
1180 else
1184 }
1187 {
1191 }
1193 /* [conv.ptr]
1194 A null pointer constant can be converted to a pointer type; ... A
1195 null pointer constant of integral type can be converted to an
1196 rvalue of type std::nullptr_t. */
1204 {
1205 /* For backwards brain damage compatibility, allow interconversion of
1206 pointers and integers with a pedwarn. */
1209 }
1211 {
1212 /* For backwards brain damage compatibility, allow interconversion of
1213 enums and integers with a pedwarn. */
1216 }
1219 {
1220 tree to_pointee;
1221 tree from_pointee;
1224 {
1228 /* Since this is the target of a pointer, it can't have function
1229 qualifiers, so any TYPE_QUALS must be for attributes const or
1230 noreturn. Strip them. */
1237 }
1238 else
1239 {
1242 }
1246 to_pointee))
1247 ;
1251 {
1253 /* Don't try to apply restrict to void. */
1258 }
1260 {
1267 && (same_type_ignoring_top_level_qualifiers_p
1269 {
1272 }
1273 else
1275 }
1278 /* [conv.ptr]
1280 An rvalue of type "pointer to cv D," where D is a
1281 class type, can be converted to an rvalue of type
1282 "pointer to cv B," where B is a base class (clause
1283 _class.derived_) of D. If B is an inaccessible
1284 (clause _class.access_) or ambiguous
1285 (_class.member.lookup_) base class of D, a program
1286 that necessitates this conversion is ill-formed.
1287 Therefore, we use DERIVED_FROM_P, and do not check
1288 access or uniqueness. */
1290 {
1291 from_pointee
1297 }
1302 /* In a C-style cast, we ignore CV-qualification because we
1303 are allowed to perform a static_cast followed by a
1304 const_cast. */
1309 /* converting from string constant to char *. */
1313 /* Allow conversions among compatible ObjC pointer types (base
1314 conversions have been already handled above). */
1319 {
1322 }
1323 else
1327 }
1329 {
1343 else
1347 {
1349 tbase,
1355 }
1358 }
1360 {
1361 /* [conv.bool]
1363 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1364 to member type can be converted to a prvalue of type bool. ...
1365 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1366 std::nullptr_t can be converted to a prvalue of type bool; */
1372 {
1383 }
1386 }
1387 /* We don't check for ENUMERAL_TYPE here because there are no standard
1388 conversions to enum type. */
1389 /* As an extension, allow conversion to complex type. */
1391 {
1398 /* Give this a better rank if it's a promotion. */
1402 }
1408 {
1412 /* The derived-to-base conversion indicates the initialization
1413 of a parameter with base type from an object of a derived
1414 type. A temporary object is created to hold the result of
1415 the conversion unless we're binding directly to a reference. */
1417 }
1418 else
1425 }
1427 /* Returns nonzero if T1 is reference-related to T2. */
1429 bool
1431 {
1438 /* [dcl.init.ref]
1440 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1441 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1442 of T2. */
1446 }
1448 /* Returns nonzero if T1 is reference-compatible with T2. */
1450 static bool
1452 {
1453 /* [dcl.init.ref]
1455 "cv1 T1" is reference compatible with "cv2 T2" if
1456 * T1 is reference-related to T2 or
1457 * T2 is "noexcept function" and T1 is "function", where the
1458 function types are otherwise the same,
1459 and cv1 is the same cv-qualification as, or greater cv-qualification
1460 than, cv2. */
1464 }
1466 /* A reference of the indicated TYPE is being bound directly to the
1467 expression represented by the implicit conversion sequence CONV.
1468 Return a conversion sequence for this binding. */
1472 {
1473 tree t;
1480 /* [over.ics.rank]
1482 When a parameter of reference type binds directly
1483 (_dcl.init.ref_) to an argument expression, the implicit
1484 conversion sequence is the identity conversion, unless the
1485 argument expression has a type that is a derived class of the
1486 parameter type, in which case the implicit conversion sequence is
1487 a derived-to-base Conversion.
1489 If the parameter binds directly to the result of applying a
1490 conversion function to the argument expression, the implicit
1491 conversion sequence is a user-defined conversion sequence
1492 (_over.ics.user_), with the second standard conversion sequence
1493 either an identity conversion or, if the conversion function
1494 returns an entity of a type that is a derived class of the
1495 parameter type, a derived-to-base conversion. */
1497 {
1498 /* Represent the derived-to-base conversion. */
1500 /* We will actually be binding to the base-class subobject in
1501 the derived class, so we mark this conversion appropriately.
1502 That way, convert_like knows not to generate a temporary. */
1504 }
1506 }
1508 /* Returns the conversion path from type FROM to reference type TO for
1509 purposes of reference binding. For lvalue binding, either pass a
1510 reference type to FROM or an lvalue expression to EXPR. If the
1511 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1512 the conversion returned. If C_CAST_P is true, this
1513 conversion is coming from a C-style cast. */
1517 tsubst_flags_t complain)
1518 {
1522 tree tfrom;
1525 cp_lvalue_kind gl_kind;
1529 {
1534 }
1537 {
1539 /* DR 1288: Otherwise, if the initializer list has a single element
1540 of type E and ... [T's] referenced type is reference-related to E,
1541 the object or reference is initialized from that element... */
1543 {
1549 {
1553 }
1554 }
1555 /* Otherwise, if T is a reference type, a prvalue temporary of the
1556 type referenced by T is copy-list-initialized or
1557 direct-list-initialized, depending on the kind of initialization
1558 for the reference, and the reference is bound to that temporary. */
1561 skip:;
1562 }
1565 {
1570 else
1572 }
1578 else
1581 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1586 /* Same mask as real_lvalue_p. */
1593 /* Figure out whether or not the types are reference-related and
1594 reference compatible. We have to do this after stripping
1595 references from FROM. */
1597 /* If this is a C cast, first convert to an appropriately qualified
1598 type, so that we can later do a const_cast to the desired type. */
1604 /* Directly bind reference when target expression's type is compatible with
1605 the reference and expression is an lvalue. In DR391, the wording in
1606 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1607 const and rvalue references to rvalues of compatible class type.
1608 We should also do direct bindings for non-class xvalues. */
1610 {
1611 /* [dcl.init.ref]
1613 If the initializer expression
1615 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1616 is reference-compatible with "cv2 T2,"
1618 the reference is bound directly to the initializer expression
1619 lvalue.
1621 [...]
1622 If the initializer expression is an rvalue, with T2 a class type,
1623 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1624 is bound to the object represented by the rvalue or to a sub-object
1625 within that object. */
1631 /* The top-level caller requested that we pretend that the lvalue
1632 be treated as an rvalue. */
1635 /* Handle rvalue reference to function properly. */
1636 conv->rvaluedness_matches_p
1638 else
1639 conv->rvaluedness_matches_p
1644 /* For the purposes of overload resolution, we ignore the fact
1645 this expression is a bitfield or packed field. (In particular,
1646 [over.ics.ref] says specifically that a function with a
1647 non-const reference parameter is viable even if the
1648 argument is a bitfield.)
1650 However, when we actually call the function we must create
1651 a temporary to which to bind the reference. If the
1652 reference is volatile, or isn't const, then we cannot make
1653 a temporary, so we just issue an error when the conversion
1654 actually occurs. */
1657 /* Don't allow binding of lvalues (other than function lvalues) to
1658 rvalue references. */
1664 /* Nor the reverse. */
1675 }
1676 /* [class.conv.fct] A conversion function is never used to convert a
1677 (possibly cv-qualified) object to the (possibly cv-qualified) same
1678 object type (or a reference to it), to a (possibly cv-qualified) base
1679 class of that type (or a reference to it).... */
1682 {
1683 /* [dcl.init.ref]
1685 If the initializer expression
1687 -- has a class type (i.e., T2 is a class type) can be
1688 implicitly converted to an lvalue of type "cv3 T3," where
1689 "cv1 T1" is reference-compatible with "cv3 T3". (this
1690 conversion is selected by enumerating the applicable
1691 conversion functions (_over.match.ref_) and choosing the
1692 best one through overload resolution. (_over.match_).
1694 the reference is bound to the lvalue result of the conversion
1695 in the second case. */
1697 complain);
1700 }
1702 /* From this point on, we conceptually need temporaries, even if we
1703 elide them. Only the cases above are "direct bindings". */
1707 /* [over.ics.rank]
1709 When a parameter of reference type is not bound directly to an
1710 argument expression, the conversion sequence is the one required
1711 to convert the argument expression to the underlying type of the
1712 reference according to _over.best.ics_. Conceptually, this
1713 conversion sequence corresponds to copy-initializing a temporary
1714 of the underlying type with the argument expression. Any
1715 difference in top-level cv-qualification is subsumed by the
1716 initialization itself and does not constitute a conversion. */
1718 /* [dcl.init.ref]
1720 Otherwise, the reference shall be an lvalue reference to a
1721 non-volatile const type, or the reference shall be an rvalue
1722 reference.
1724 We try below to treat this as a bad conversion to improve diagnostics,
1725 but if TO is an incomplete class, we need to reject this conversion
1726 now to avoid unnecessary instantiation. */
1731 /* We're generating a temporary now, but don't bind any more in the
1732 conversion (specifically, don't slice the temporary returned by a
1733 conversion operator). */
1736 /* Core issue 899: When [copy-]initializing a temporary to be bound
1737 to the first parameter of a copy constructor (12.8) called with
1738 a single argument in the context of direct-initialization,
1739 explicit conversion functions are also considered.
1741 So don't set LOOKUP_ONLYCONVERTING in that case. */
1752 {
1753 /* If initializing the temporary used a conversion function,
1754 recalculate the second conversion sequence. */
1758 {
1761 conversion *new_second
1767 }
1768 }
1771 /* This reference binding, unlike those above, requires the
1772 creation of a temporary. */
1776 /* [dcl.init.ref]
1778 Otherwise, the reference shall be an lvalue reference to a
1779 non-volatile const type, or the reference shall be an rvalue
1780 reference. */
1784 /* [dcl.init.ref]
1786 Otherwise, a temporary of type "cv1 T1" is created and
1787 initialized from the initializer expression using the rules for a
1788 non-reference copy initialization. If T1 is reference-related to
1789 T2, cv1 must be the same cv-qualification as, or greater
1790 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1795 }
1797 /* Returns the implicit conversion sequence (see [over.ics]) from type
1798 FROM to type TO. The optional expression EXPR may affect the
1799 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1800 true, this conversion is coming from a C-style cast. */
1805 {
1812 /* Other flags only apply to the primary function in overload
1813 resolution, or after we've chosen one. */
1818 /* FIXME: actually we don't want warnings either, but we can't just
1819 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1820 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1821 We really ought not to issue that warning until we've committed
1822 to that conversion. */
1825 /* Call reshape_init early to remove redundant braces. */
1830 {
1835 }
1839 else
1846 {
1850 /* As an extension, allow list-initialization of _Complex. */
1852 {
1856 }
1858 /* Allow conversion from an initializer-list with one element to a
1859 scalar type. */
1861 {
1863 tree elt;
1869 else
1875 {
1878 /* Too many levels of braces, i.e. '{{1}}'. */
1881 }
1882 }
1885 }
1891 {
1901 {
1905 {
1906 /* "If C is not an initializer-list constructor and the
1907 initializer list has a single element of type cv U, where U is
1908 X or a class derived from X, the implicit conversion sequence
1909 has Exact Match rank if U is X, or Conversion rank if U is
1910 derived from X." */
1916 }
1918 }
1920 /* We used to try to bind a reference to a temporary here, but that
1921 is now handled after the recursive call to this function at the end
1922 of reference_binding. */
1924 }
1927 }
1929 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1930 functions. ARGS will not be changed until a single candidate is
1931 selected. */
1940 {
1958 }
1960 /* Return the number of remaining arguments in the parameter list
1961 beginning with ARG. */
1963 int
1965 {
1970 n++;
1973 }
1975 /* Create an overload candidate for the function or method FN called
1976 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1977 FLAGS is passed on to implicit_conversion.
1979 This does not change ARGS.
1981 CTYPE, if non-NULL, is the type we want to pretend this function
1982 comes from for purposes of overload resolution. */
1989 tsubst_flags_t complain)
1990 {
1994 tree parmnode;
2000 /* At this point we should not see any functions which haven't been
2001 explicitly declared, except for friend functions which will have
2002 been found using argument dependent lookup. */
2005 /* The `this', `in_chrg' and VTT arguments to constructors are not
2006 considered in overload resolution. */
2008 {
2010 /* Bring back parameters omitted from an inherited ctor. */
2012 else
2016 {
2019 }
2020 }
2021 else
2027 /* 13.3.2 - Viable functions [over.match.viable]
2028 First, to be a viable function, a candidate function shall have enough
2029 parameters to agree in number with the arguments in the list.
2031 We need to check this first; otherwise, checking the ICSes might cause
2032 us to produce an ill-formed template instantiation. */
2036 {
2040 }
2044 {
2048 }
2050 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2051 parameter of type "reference to cv C" (including such a constructor
2052 instantiated from a template) is excluded from the set of candidate
2053 functions when used to construct an object of type D with an argument list
2054 containing a single argument if C is reference-related to D. */
2056 && flag_new_inheriting_ctors
2058 {
2064 {
2067 }
2068 }
2070 /* Second, for a function to be viable, its constraints must be
2071 satisfied. */
2074 {
2077 }
2079 /* When looking for a function from a subobject from an implicit
2080 copy/move constructor/operator=, don't consider anything that takes (a
2081 reference to) an unrelated type. See c++/44909 and core 1092. */
2083 {
2089 else
2092 {
2095 ctype))
2097 }
2099 /* This only applies at the top level. */
2101 }
2106 /* Third, for F to be a viable function, there shall exist for each
2107 argument an implicit conversion sequence that converts that argument
2108 to the corresponding parameter of F. */
2113 {
2115 tree arg;
2124 else
2133 {
2139 /* The type of the implicit object parameter ('this') for
2140 overload resolution is not always the same as for the
2141 function itself; conversion functions are considered to
2142 be members of the class being converted, and functions
2143 introduced by a using-declaration are considered to be
2144 members of the class that uses them.
2146 Since build_over_call ignores the ICS for the `this'
2147 parameter, we can just change the parm type. */
2149 {
2150 parmtype = cp_build_qualified_type
2153 {
2154 /* If the function has a ref-qualifier, the implicit
2155 object parameter has reference type. */
2158 /* The special handling of 'this' conversions in compare_ics
2159 does not apply if there is a ref-qualifier. */
2161 }
2162 else
2163 {
2167 }
2168 }
2170 /* Core issue 899: When [copy-]initializing a temporary to be bound
2171 to the first parameter of a copy constructor (12.8) called with
2172 a single argument in the context of direct-initialization,
2173 explicit conversion functions are also considered.
2175 So set LOOKUP_COPY_PARM to let reference_binding know that
2176 it's being called in that context. We generalize the above
2177 to handle move constructors and template constructors as well;
2178 the standardese should soon be updated similarly. */
2182 && (same_type_ignoring_top_level_qualifiers_p
2184 {
2187 /* We allow user-defined conversions within init-lists, but
2188 don't list-initialize the copy parm, as that would mean
2189 using two levels of braces for the same type. */
2193 }
2194 else
2200 }
2201 else
2202 {
2206 }
2213 {
2217 }
2220 {
2223 }
2224 }
2226 out:
2229 }
2231 /* Create an overload candidate for the conversion function FN which will
2232 be invoked for expression OBJ, producing a pointer-to-function which
2233 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2234 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2235 passed on to implicit_conversion.
2237 Actually, we don't really care about FN; we care about the type it
2238 converts to. There may be multiple conversion functions that will
2239 convert to that type, and we rely on build_user_type_conversion_1 to
2240 choose the best one; so when we create our candidate, we record the type
2241 instead of the function. */
2247 tsubst_flags_t complain)
2248 {
2266 /* Don't bother looking up the same type twice. */
2271 {
2277 else
2282 {
2286 }
2290 {
2294 }
2295 else
2296 {
2300 }
2307 {
2310 }
2317 }
2321 {
2325 }
2329 }
2331 static void
2335 {
2349 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2350 conversion ops are allowed. We handle that here by just checking for
2351 boolean_type_node because other operators don't ask for it. COND_EXPR
2352 also does contextual conversion to bool for the first operand, but we
2353 handle that in build_conditional_expr, and type1 here is operand 2. */
2358 {
2365 {
2367 /* We need something for printing the candidate. */
2371 }
2373 {
2377 }
2379 }
2381 /* For COND_EXPR we rearranged the arguments; undo that now. */
2383 {
2388 complain);
2391 else
2392 {
2395 boolean_type_node);
2396 }
2397 }
2404 }
2406 static bool
2408 {
2410 }
2412 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2414 static bool
2416 {
2417 /* [over.built]
2419 In this section, the term promoted integral type is used to refer
2420 to those integral types which are preserved by integral promotion
2421 (including e.g. int and long but excluding e.g. char).
2422 Similarly, the term promoted arithmetic type refers to promoted
2423 integral types plus floating types. */
2427 }
2429 /* Create any builtin operator overload candidates for the operator in
2430 question given the converted operand types TYPE1 and TYPE2. The other
2431 args are passed through from add_builtin_candidates to
2432 build_builtin_candidate.
2434 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2435 If CODE is requires candidates operands of the same type of the kind
2436 of which TYPE1 and TYPE2 are, we add both candidates
2437 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2439 static void
2443 tsubst_flags_t complain)
2444 {
2446 {
2454 }
2457 {
2459 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2460 and VQ is either volatile or empty, there exist candidate operator
2461 functions of the form
2462 VQ T& operator++(VQ T&);
2463 T operator++(VQ T&, int);
2464 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2465 type other than bool, and VQ is either volatile or empty, there exist
2466 candidate operator functions of the form
2467 VQ T& operator--(VQ T&);
2468 T operator--(VQ T&, int);
2469 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2470 complete object type, and VQ is either volatile or empty, there exist
2471 candidate operator functions of the form
2472 T*VQ& operator++(T*VQ&);
2473 T*VQ& operator--(T*VQ&);
2474 T* operator++(T*VQ&, int);
2475 T* operator--(T*VQ&, int); */
2481 /* FALLTHRU */
2485 {
2488 }
2491 /* 7 For every cv-qualified or cv-unqualified object type T, there
2492 exist candidate operator functions of the form
2494 T& operator*(T*);
2496 8 For every function type T, there exist candidate operator functions of
2497 the form
2498 T& operator*(T*); */
2507 /* 9 For every type T, there exist candidate operator functions of the form
2508 T* operator+(T*);
2510 10For every promoted arithmetic type T, there exist candidate operator
2511 functions of the form
2512 T operator+(T);
2513 T operator-(T); */
2518 /* FALLTHRU */
2524 /* 11For every promoted integral type T, there exist candidate operator
2525 functions of the form
2526 T operator~(T); */
2533 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2534 is the same type as C2 or is a derived class of C2, T is a complete
2535 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2536 there exist candidate operator functions of the form
2537 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2538 where CV12 is the union of CV1 and CV2. */
2542 {
2550 }
2553 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2554 didate operator functions of the form
2555 LR operator*(L, R);
2556 LR operator/(L, R);
2557 LR operator+(L, R);
2558 LR operator-(L, R);
2559 bool operator<(L, R);
2560 bool operator>(L, R);
2561 bool operator<=(L, R);
2562 bool operator>=(L, R);
2563 bool operator==(L, R);
2564 bool operator!=(L, R);
2565 where LR is the result of the usual arithmetic conversions between
2566 types L and R.
2568 14For every pair of types T and I, where T is a cv-qualified or cv-
2569 unqualified complete object type and I is a promoted integral type,
2570 there exist candidate operator functions of the form
2571 T* operator+(T*, I);
2572 T& operator[](T*, I);
2573 T* operator-(T*, I);
2574 T* operator+(I, T*);
2575 T& operator[](I, T*);
2577 15For every T, where T is a pointer to complete object type, there exist
2578 candidate operator functions of the form112)
2579 ptrdiff_t operator-(T, T);
2581 16For every pointer or enumeration type T, there exist candidate operator
2582 functions of the form
2583 bool operator<(T, T);
2584 bool operator>(T, T);
2585 bool operator<=(T, T);
2586 bool operator>=(T, T);
2587 bool operator==(T, T);
2588 bool operator!=(T, T);
2590 17For every pointer to member type T, there exist candidate operator
2591 functions of the form
2592 bool operator==(T, T);
2593 bool operator!=(T, T); */
2600 {
2603 }
2604 /* FALLTHRU */
2617 {
2620 }
2622 {
2625 }
2626 /* Fall through. */
2642 {
2645 }
2648 {
2651 }
2657 /* FALLTHRU */
2660 {
2663 }
2665 {
2668 }
2671 /* 18For every pair of promoted integral types L and R, there exist candi-
2672 date operator functions of the form
2673 LR operator%(L, R);
2674 LR operator&(L, R);
2675 LR operator^(L, R);
2676 LR operator|(L, R);
2677 L operator<<(L, R);
2678 L operator>>(L, R);
2679 where LR is the result of the usual arithmetic conversions between
2680 types L and R. */
2688 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2692 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2693 type, VQ is either volatile or empty, and R is a promoted arithmetic
2694 type, there exist candidate operator functions of the form
2695 VQ L& operator=(VQ L&, R);
2696 VQ L& operator*=(VQ L&, R);
2697 VQ L& operator/=(VQ L&, R);
2698 VQ L& operator+=(VQ L&, R);
2699 VQ L& operator-=(VQ L&, R);
2701 20For every pair T, VQ), where T is any type and VQ is either volatile
2702 or empty, there exist candidate operator functions of the form
2703 T*VQ& operator=(T*VQ&, T*);
2705 21For every pair T, VQ), where T is a pointer to member type and VQ is
2706 either volatile or empty, there exist candidate operator functions of
2707 the form
2708 VQ T& operator=(VQ T&, T);
2710 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2711 unqualified complete object type, VQ is either volatile or empty, and
2712 I is a promoted integral type, there exist candidate operator func-
2713 tions of the form
2714 T*VQ& operator+=(T*VQ&, I);
2715 T*VQ& operator-=(T*VQ&, I);
2717 23For every triple L, VQ, R), where L is an integral or enumeration
2718 type, VQ is either volatile or empty, and R is a promoted integral
2719 type, there exist candidate operator functions of the form
2721 VQ L& operator%=(VQ L&, R);
2722 VQ L& operator<<=(VQ L&, R);
2723 VQ L& operator>>=(VQ L&, R);
2724 VQ L& operator&=(VQ L&, R);
2725 VQ L& operator^=(VQ L&, R);
2726 VQ L& operator|=(VQ L&, R); */
2730 {
2734 {
2737 }
2738 /* FALLTHRU */
2751 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2764 {
2767 }
2772 }
2777 /* [over.built]
2779 For every pair of promoted arithmetic types L and R, there
2780 exist candidate operator functions of the form
2782 LR operator?(bool, L, R);
2784 where LR is the result of the usual arithmetic conversions
2785 between types L and R.
2787 For every type T, where T is a pointer or pointer-to-member
2788 type, there exist candidate operator functions of the form T
2789 operator?(bool, T, T); */
2793 /* That's OK. */
2796 /* Otherwise, the types should be pointers. */
2800 /* We don't check that the two types are the same; the logic
2801 below will actually create two candidates; one in which both
2802 parameter types are TYPE1, and one in which both parameter
2803 types are TYPE2. */
2814 }
2816 /* Make sure we don't create builtin candidates with dependent types. */
2820 {
2821 /* Try to recover if one of the types is non-dependent. But if
2822 there's only one type, there's nothing we can do. */
2825 /* And we lose if both are dependent. */
2828 /* Or if they have different forms. */
2836 }
2838 /* If we're dealing with two pointer types or two enumeral types,
2839 we need candidates for both of them. */
2848 {
2850 {
2852 error_mark_node,
2853 error_mark_node,
2854 CPO_CONVERSION,
2855 tf_none);
2857 {
2858 build_builtin_candidate
2862 }
2863 }
2865 build_builtin_candidate
2867 build_builtin_candidate
2870 }
2872 build_builtin_candidate
2874 }
2876 tree
2878 {
2884 }
2886 /* There are three conditions of builtin candidates:
2888 1) bool-taking candidates. These are the same regardless of the input.
2889 2) pointer-pair taking candidates. These are generated for each type
2890 one of the input types converts to.
2891 3) arithmetic candidates. According to the standard, we should generate
2892 all of these, but I'm trying not to...
2894 Here we generate a superset of the possible candidates for this particular
2895 case. That is a subset of the full set the standard defines, plus some
2896 other cases which the standard disallows. add_builtin_candidate will
2897 filter out the invalid set. */
2899 static void
2903 {
2907 /* TYPES[i] is the set of possible builtin-operator parameter types
2908 we will consider for the Ith argument. */
2913 {
2916 else
2918 }
2921 {
2922 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2923 and VQ is either volatile or empty, there exist candidate operator
2924 functions of the form
2925 VQ T& operator++(VQ T&); */
2935 /* 24There also exist candidate operator functions of the form
2936 bool operator!(bool);
2937 bool operator&&(bool, bool);
2938 bool operator||(bool, bool); */
2941 build_builtin_candidate
2948 build_builtin_candidate
2966 /* Fall through. */
2970 }
2976 {
2978 ;
2980 {
2981 tree convs;
2989 {
2994 }
3000 {
3013 {
3019 }
3023 }
3024 }
3025 else
3026 {
3031 {
3037 }
3039 }
3040 }
3042 /* Run through the possible parameter types of both arguments,
3043 creating candidates with those parameter types. */
3045 {
3047 tree u;
3051 add_builtin_candidate
3054 else
3055 add_builtin_candidate
3058 }
3062 }
3065 /* If TMPL can be successfully instantiated as indicated by
3066 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3068 TMPL is the template. EXPLICIT_TARGS are any explicit template
3069 arguments. ARGLIST is the arguments provided at the call-site.
3070 This does not change ARGLIST. The RETURN_TYPE is the desired type
3071 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3072 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3073 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3081 tsubst_flags_t complain)
3082 {
3092 tree arg;
3094 tree fn;
3098 /* We don't do deduction on the in-charge parameter, the VTT
3099 parameter or 'this'. */
3101 {
3105 /* We're deducing for a call to the result of a template conversion
3107 else
3109 }
3114 {
3117 else
3119 }
3127 {
3128 /* 12.8/6 says, "A declaration of a constructor for a class X is
3129 ill-formed if its first parameter is of type (optionally cv-qualified)
3130 X and either there are no other parameters or else all other
3131 parameters have default arguments. A member function template is never
3132 instantiated to produce such a constructor signature."
3134 So if we're trying to copy an object of the containing class, don't
3135 consider a template constructor that has a first parameter type that
3136 is just a template parameter, as we would deduce a signature that we
3137 would then reject in the code below. */
3139 {
3144 {
3148 }
3149 }
3150 }
3157 {
3160 }
3164 {
3167 }
3172 args_without_in_chrg,
3173 nargs_without_in_chrg,
3178 {
3179 /* Don't repeat unification later if it already resulted in errors. */
3183 nargs_without_in_chrg,
3185 else
3188 }
3191 {
3194 ctype))
3195 {
3196 /* We're trying to produce a constructor with a prohibited signature,
3197 as discussed above; handle here any cases we didn't catch then,
3198 such as X(X<T>). */
3201 }
3202 }
3205 /* Aha, this is a conversion function. */
3208 else
3213 /* This situation can occur if a member template of a template
3214 class is specialized. Then, instantiate_template might return
3215 an instantiation of the specialization, in which case the
3216 DECL_TI_TEMPLATE field will point at the original
3217 specialization. For example:
3219 template <class T> struct S { template <class U> void f(U);
3220 template <> void f(int) {}; };
3221 S<double> sd;
3222 sd.f(3);
3224 Here, TMPL will be template <class U> S<double>::f(U).
3225 And, instantiate template will give us the specialization
3226 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3227 for this will point at template <class T> template <> S<T>::f(int),
3228 so that we can find the definition. For the purposes of
3229 overload resolution, however, we want the original TMPL. */
3231 else
3236 fail:
3239 }
3248 {
3249 return
3254 }
3256 /* Create an overload candidate for the conversion function template TMPL,
3257 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3258 pointer-to-function which will in turn be called with the argument list
3259 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3260 passed on to implicit_conversion. */
3264 tree obj,
3268 {
3269 /* Making this work broke PR 71117, so until the committee resolves core
3270 issue 2189, let's disable this candidate if there are any viable call
3271 operators. */
3275 return
3279 complain);
3280 }
3282 /* The CANDS are the set of candidates that were considered for
3283 overload resolution. Return the set of viable candidates, or CANDS
3284 if none are viable. If any of the candidates were viable, set
3285 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3286 considered viable only if it is strictly viable. */
3292 {
3298 /* Be strict inside templates, since build_over_call won't actually
3299 do the conversions to get pedwarns. */
3309 {
3313 {
3314 /* Be strict in the presence of a viable candidate. Also if
3315 there are template candidates, so that we get deduction errors
3316 for them instead of silently preferring a bad conversion. */
3319 {
3320 /* Put any spliced near matches back onto the main list so
3321 that we see them if there is no strict match. */
3327 }
3328 }
3331 {
3339 }
3340 else
3342 }
3345 }
3347 static bool
3349 {
3354 }
3356 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3357 words, it is about to become the "this" pointer for a member
3358 function call. Take the address of the object. */
3360 static tree
3362 {
3363 /* In a template, we are only concerned about the type of the
3364 expression, so we can take a shortcut. */
3369 }
3371 /* Returns true iff functions are equivalent. Equivalent functions are
3372 not '==' only if one is a function-local extern function or if
3373 both are extern "C". */
3377 {
3386 }
3388 /* Print information about a candidate being rejected due to INFO. */
3390 static void
3392 {
3397 {
3398 /* Conversion of implicit `this' argument failed. */
3400 /* A bad conversion for 'this' must be discarding cv-quals. */
3403 from);
3404 else
3408 }
3410 {
3415 tf_warning_or_error);
3416 }
3418 /* Conversion of conversion function return value failed. */
3421 else
3424 }
3426 /* Print information about a candidate with WANT parameters and we found
3427 HAVE. */
3429 static void
3431 {
3436 }
3438 /* Print information about one overload candidate CANDIDATE. MSGSTR
3439 is the text to print before the candidate itself.
3441 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3442 to have been run through gettext by the caller. This wart makes
3443 life simpler in print_z_candidates and for the translators. */
3445 static void
3448 {
3458 {
3469 else
3472 }
3479 else
3482 {
3485 }
3486 /* Give the user some information about why this candidate failed. */
3488 {
3492 {
3505 "cannot be converted to %qT with a qualification "
3511 "conversion function specialization to %qT is not an "
3516 /* We use template_unification_error_rejection if unification caused
3517 actual non-SFINAE errors, in which case we don't need to repeat
3518 them here. */
3520 {
3524 }
3525 /* Re-run template unification with diagnostics. */
3529 (make_tree_vec
3540 " a constructor taking a single argument of its own "
3544 {
3548 }
3552 "initialization from an expression of the same or derived "
3557 /* This candidate didn't have any issues or we failed to
3558 handle a particular code. Either way... */
3560 }
3561 }
3562 }
3564 static void
3566 {
3573 /* Remove non-viable deleted candidates. */
3576 {
3581 else
3583 }
3584 /* ...if there are any non-deleted ones. */
3588 /* There may be duplicates in the set of candidates. We put off
3589 checking this condition as long as possible, since we have no way
3590 to eliminate duplicates from a set of functions in less than n^2
3591 time. Now we are about to emit an error message, so it is more
3592 permissible to go slowly. */
3594 {
3596 /* Skip builtin candidates and conversion functions. */
3601 {
3605 else
3607 }
3608 }
3612 }
3614 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3615 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3616 the result of the conversion function to convert it to the final
3617 desired type. Merge the two sequences into a single sequence,
3618 and return the merged sequence. */
3622 {
3628 /* Find the end of the second conversion sequence. */
3630 {
3631 /* The entire sequence is a user-conversion sequence. */
3635 }
3637 /* Replace the identity conversion with the user conversion
3638 sequence. */
3642 }
3644 /* Handle overload resolution for initializing an object of class type from
3645 an initializer list. First we look for a suitable constructor that
3646 takes a std::initializer_list; if we don't find one, we then look for a
3647 non-list constructor.
3649 Parameters are as for add_candidates, except that the arguments are in
3650 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3651 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3653 static void
3660 tsubst_flags_t complain)
3661 {
3664 /* We're looking for a ctor for list-initialization. */
3666 /* And we don't allow narrowing conversions. We also use this flag to
3667 avoid the copy constructor call for copy-list-initialization. */
3673 /* Always use the default constructor if the list is empty (DR 990). */
3676 ;
3677 /* If the class has a list ctor, try passing the list as a single
3678 argument first, but only consider list ctors. */
3680 {
3687 }
3689 /* Expand the CONSTRUCTOR into a new argument vec. */
3697 /* We aren't looking for list-ctors anymore. */
3699 /* We allow more user-defined conversions within an init-list. */
3705 }
3707 /* Returns the best overload candidate to perform the requested
3708 conversion. This function is used for three the overloading situations
3709 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3710 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3711 per [dcl.init.ref], so we ignore temporary bindings. */
3715 tsubst_flags_t complain)
3716 {
3718 tree fromtype;
3732 /* We represent conversion within a hierarchy using RVALUE_CONV and
3733 BASE_CONV, as specified by [over.best.ics]; these become plain
3734 constructor calls, as specified in [dcl.init]. */
3739 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3740 creating a garbage BASELINK; constructors can't be inherited. */
3743 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3744 a single element. For now, let's handle constructors as before and also
3745 consider conversion operators from the element. */
3752 {
3757 {
3758 /* [class.conv.fct] A conversion function is never used to
3759 convert a (possibly cv-qualified) object to the (possibly
3760 cv-qualified) same object type (or a reference to it), to a
3761 (possibly cv-qualified) base class of that type (or a
3762 reference to it)... */
3763 }
3764 else
3766 }
3773 /* It's OK to bind a temporary for converting constructor arguments, but
3774 not in converting the return value of a conversion operator. */
3780 {
3785 /* We should never try to call the abstract or base constructor
3786 from here. */
3792 {
3793 /* List-initialization. */
3797 }
3798 else
3799 {
3803 }
3806 {
3809 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3810 set, then this is copy-initialization. In that case, "The
3811 result of the call is then used to direct-initialize the
3812 object that is the destination of the copy-initialization."
3813 [dcl.init]
3815 We represent this in the conversion sequence with an
3816 rvalue conversion, which means a constructor call. */
3819 cand->second_conv
3821 }
3822 }
3825 {
3827 /* FIXME see above about C++17. */
3829 else
3831 }
3834 {
3838 /* If we are called to convert to a reference type, we are trying to
3839 find a direct binding, so don't even consider temporaries. If
3840 we don't find a direct binding, the caller will try again to
3841 look for a temporary binding. */
3852 {
3854 conversion *ics
3856 rettype,
3859 complain);
3861 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3862 copy-initialization. In that case, "The result of the
3863 call is then used to direct-initialize the object that is
3864 the destination of the copy-initialization." [dcl.init]
3866 We represent this in the conversion sequence with an
3867 rvalue conversion, which means a constructor call. But
3868 don't add a second rvalue conversion if there's already
3869 one there. Which there really shouldn't be, but it's
3870 harmless since we'd add it here anyway. */
3878 {
3882 }
3885 {
3886 /* 13.3.1.5: For direct-initialization, those explicit
3887 conversion functions that are not hidden within S and
3888 yield type T or a type that can be converted to type T
3889 with a qualification conversion (4.4) are also candidate
3890 functions. */
3891 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3892 I've raised this issue with the committee. --jason 9/2011 */
3895 }
3897 {
3899 cand->reason
3902 }
3905 {
3906 /* 13.3.3.1.2: If the user-defined conversion is specified by
3907 a specialization of a conversion function template, the
3908 second standard conversion sequence shall have exact match
3909 rank. */
3912 }
3913 }
3914 }
3918 {
3922 }
3926 {
3928 {
3932 }
3939 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3940 ambiguous conversion is no worse than another user-defined
3941 conversion. */
3944 }
3946 tree convtype;
3950 /* DR 5: [in the first step of copy-initialization]...if the function
3951 is a constructor, the call initializes a temporary of the
3952 cv-unqualified version of the destination type. */
3954 else
3956 /* Build the user conversion sequence. */
3957 conv = build_conv
3959 convtype,
3965 /* Remember that this was a list-initialization. */
3969 /* Combine it with the second conversion sequence. */
3974 }
3976 /* Wrapper for above. */
3978 tree
3980 tsubst_flags_t complain)
3981 {
3983 tree ret;
3989 {
3992 else
3993 {
3996 }
3997 }
3998 else
4003 }
4005 /* Subroutine of convert_nontype_argument.
4007 EXPR is an expression used in a context that requires a converted
4008 constant-expression, such as a template non-type parameter. Do any
4009 necessary conversions (that are permitted for converted
4010 constant-expressions) to convert it to the desired type.
4012 If conversion is successful, returns the converted expression;
4013 otherwise, returns error_mark_node. */
4015 tree
4017 {
4020 tree t;
4026 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4033 /* A converted constant expression of type T is an expression, implicitly
4034 converted to type T, where the converted expression is a constant
4035 expression and the implicit conversion sequence contains only
4037 * user-defined conversions,
4038 * lvalue-to-rvalue conversions (7.1),
4039 * array-to-pointer conversions (7.2),
4040 * function-to-pointer conversions (7.3),
4041 * qualification conversions (7.5),
4042 * integral promotions (7.6),
4043 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4044 * null pointer conversions (7.11) from std::nullptr_t,
4045 * null member pointer conversions (7.12) from std::nullptr_t, and
4046 * function pointer conversions (7.13),
4048 and where the reference binding (if any) binds directly. */
4053 {
4055 {
4056 /* A conversion function is OK. If it isn't constexpr, we'll
4057 complain later that the argument isn't constant. */
4059 /* The lvalue-to-rvalue conversion is OK. */
4061 /* Array-to-pointer and function-to-pointer. */
4063 /* Function pointer conversions. */
4065 /* Qualification conversions. */
4071 {
4077 }
4087 /* Integral promotion or conversion. */
4090 /* Conversion from nullptr to pointer or pointer-to-member. */
4096 /* fall through. */
4101 }
4102 }
4104 /* Avoid confusing convert_nontype_argument by introducing
4105 a redundant conversion to the same reference type. */
4108 {
4112 }
4116 else
4119 /* Free all the conversions we allocated. */
4123 }
4125 /* Do any initial processing on the arguments to a function call. */
4129 {
4131 tree arg;
4134 {
4138 {
4142 }
4145 }
4147 }
4149 /* Perform overload resolution on FN, which is called with the ARGS.
4151 Return the candidate function selected by overload resolution, or
4152 NULL if the event that overload resolution failed. In the case
4153 that overload resolution fails, *CANDIDATES will be the set of
4154 candidates considered, and ANY_VIABLE_P will be set to true or
4155 false to indicate whether or not any of the candidates were
4156 viable.
4158 The ARGS should already have gone through RESOLVE_ARGS before this
4159 function is called. */
4166 {
4168 tree explicit_targs;
4179 /* Check FN. */
4186 {
4190 }
4192 /* Add the various candidate functions. */
4197 LOOKUP_NORMAL,
4203 else
4208 }
4210 /* Print an error message about being unable to build a call to FN with
4211 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4212 be located; CANDIDATES is a possibly empty list of such
4213 functions. */
4215 static void
4218 {
4221 {
4224 }
4233 else
4238 }
4240 /* Return an expression for a call to FN (a namespace-scope function,
4241 or a static member function) with the ARGS. This may change
4242 ARGS. */
4244 tree
4246 tsubst_flags_t complain)
4247 {
4251 tree result;
4254 {
4258 }
4263 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4267 complain);
4270 {
4272 {
4273 // If there is a single (non-viable) function candidate,
4274 // let the error be diagnosed by cp_build_function_call_vec.
4279 // Otherwise, emit notes for non-viable candidates.
4281 }
4283 }
4284 else
4285 {
4287 /* If fn is template_id_expr, the call has explicit template arguments
4288 (e.g. func<int>(5)), communicate this info to build_over_call
4289 through flags so that later we can use it to decide whether to warn
4290 about peculiar null pointer conversion. */
4292 {
4293 /* If overload resolution selects a specialization of a
4294 function concept for non-dependent template arguments,
4295 the expression is true if the constraints are satisfied
4296 and false otherwise.
4298 NOTE: This is an extension of Concepts Lite TS that
4299 allows constraints to be used in expressions. */
4301 {
4307 }
4310 }
4313 }
4315 /* Free all the conversions we allocated. */
4319 }
4321 /* Build a call to a global operator new. FNNAME is the name of the
4322 operator (either "operator new" or "operator new[]") and ARGS are
4323 the arguments provided. This may change ARGS. *SIZE points to the
4324 total number of bytes required by the allocation, and is updated if
4325 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4326 be used. If this function determines that no cookie should be
4327 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4328 is not NULL_TREE, it is evaluated before calculating the final
4329 array size, and if it fails, the array size is replaced with
4330 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4331 is non-NULL, it will be set, upon return, to the allocation
4332 function called. */
4334 tree
4339 {
4341 tree fns;
4348 /* Set to (size_t)-1 if the size check fails. */
4350 {
4356 }
4362 /* Based on:
4364 [expr.new]
4366 If this lookup fails to find the name, or if the allocated type
4367 is not a class type, the allocation function's name is looked
4368 up in the global scope.
4370 we disregard block-scope declarations of "operator new". */
4375 {
4380 /* If no aligned allocation function matches, try again without the
4381 alignment. */
4382 }
4384 /* Figure out what function is being called. */
4387 complain);
4389 /* If no suitable function could be found, issue an error message
4390 and give up. */
4392 {
4396 }
4398 /* If a cookie is required, add some extra space. Whether
4399 or not a cookie is required cannot be determined until
4400 after we know which function was called. */
4402 {
4404 tree arg_types;
4407 /* Skip the size_t parameter. */
4409 /* Check the remaining parameters (if any). */
4413 ptr_type_node))
4415 /* If we need a cookie, adjust the number of bytes allocated. */
4417 {
4418 /* Update the total size. */
4421 {
4422 /* Set to (size_t)-1 if the size check fails. */
4426 }
4427 /* Update the argument list to reflect the adjusted size. */
4429 }
4430 else
4432 }
4434 /* Tell our caller which function we decided to call. */
4438 /* Build the CALL_EXPR. */
4440 }
4442 /* Build a new call to operator(). This may change ARGS. */
4444 static tree
4446 {
4460 {
4462 /* It's no good looking for an overloaded operator() on a
4463 pointer-to-member-function. */
4467 }
4470 {
4474 }
4475 else
4479 {
4483 }
4485 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4489 {
4497 }
4502 {
4510 {
4517 add_template_conv_candidate
4521 else
4525 }
4526 }
4528 /* Be strict here because if we choose a bad conversion candidate, the
4529 errors we get won't mention the call context. */
4532 {
4534 {
4538 }
4540 }
4541 else
4542 {
4545 {
4547 {
4551 }
4553 }
4554 /* Since cand->fn will be a type, not a function, for a conversion
4555 function, we must be careful not to unconditionally look at
4556 DECL_NAME here. */
4560 else
4561 {
4565 else
4569 }
4570 }
4572 /* Free all the conversions we allocated. */
4576 }
4578 /* Wrapper for above. */
4580 tree
4582 {
4583 tree ret;
4588 }
4590 /* Called by op_error to prepare format strings suitable for the error
4591 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4592 and a suffix (controlled by NTYPES). */
4596 {
4606 else
4610 }
4612 static void
4615 {
4620 else
4624 {
4630 else
4642 else
4652 else
4663 else
4673 else
4678 else
4682 else
4687 }
4688 }
4690 /* Return the implicit conversion sequence that could be used to
4691 convert E1 to E2 in [expr.cond]. */
4695 {
4701 /* [expr.cond]
4703 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4704 implicitly converted (clause _conv_) to the type "lvalue reference to
4705 T2", subject to the constraint that in the conversion the
4706 reference must bind directly (_dcl.init.ref_) to an lvalue.
4708 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4709 implicitly converted to the type "rvalue reference to T2", subject to
4710 the constraint that the reference must bind directly. */
4712 {
4715 t1,
4716 e1,
4718 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4720 complain);
4723 }
4725 /* If E2 is a prvalue or if neither of the conversions above can be done
4726 and at least one of the operands has (possibly cv-qualified) class
4727 type: */
4731 /* [expr.cond]
4733 If E1 and E2 have class type, and the underlying class types are
4734 the same or one is a base class of the other: E1 can be converted
4735 to match E2 if the class of T2 is the same type as, or a base
4736 class of, the class of T1, and the cv-qualification of T2 is the
4737 same cv-qualification as, or a greater cv-qualification than, the
4738 cv-qualification of T1. If the conversion is applied, E1 is
4739 changed to an rvalue of type T2 that still refers to the original
4740 source class object (or the appropriate subobject thereof). */
4743 {
4745 {
4750 else
4753 }
4754 else
4756 }
4757 else
4758 /* [expr.cond]
4760 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4761 converted to the type that expression E2 would have if E2 were
4762 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4765 }
4767 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4768 arguments to the conditional expression. */
4770 static tree
4772 tsubst_flags_t complain)
4773 {
4774 tree arg2_type;
4775 tree arg3_type;
4784 /* As a G++ extension, the second argument to the conditional can be
4785 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4786 c'.) If the second operand is omitted, make sure it is
4787 calculated only once. */
4789 {
4797 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4800 else
4802 }
4804 /* If something has already gone wrong, just pass that fact up the
4805 tree. */
4815 {
4818 /* If arg1 is another cond_expr choosing between -1 and 0,
4819 then we can use its comparison. It may help to avoid
4820 additional comparison, produce more accurate diagnostics
4821 and enables folding. */
4831 /* force_rvalue can return error_mark on valid arguments. */
4842 {
4843 /* Rely on the error messages of the scalar version. */
4852 {
4860 }
4864 /* We could pass complain & tf_warning to unsafe_conversion_p,
4865 but the warnings (like Wsign-conversion) have already been
4866 given by the scalar build_conditional_expr_1. We still check
4867 unsafe_conversion_p to forbid truncating long long -> float. */
4869 {
4874 }
4876 {
4881 }
4891 }
4894 {
4900 {
4904 {
4910 }
4912 {
4918 }
4921 }
4922 }
4928 {
4931 "incompatible vector types in conditional expression: "
4935 }
4938 {
4941 }
4943 }
4945 /* [expr.cond]
4947 The first expression is implicitly converted to bool (clause
4948 _conv_). */
4950 LOOKUP_NORMAL);
4954 /* [expr.cond]
4956 If either the second or the third operand has type (possibly
4957 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4958 array-to-pointer (_conv.array_), and function-to-pointer
4959 (_conv.func_) standard conversions are performed on the second
4960 and third operands. */
4964 {
4965 /* Do the conversions. We don't these for `void' type arguments
4966 since it can't have any effect and since decay_conversion
4967 does not handle that case gracefully. */
4975 /* [expr.cond]
4977 One of the following shall hold:
4979 --The second or the third operand (but not both) is a
4980 throw-expression (_except.throw_); the result is of the
4981 type of the other and is an rvalue.
4983 --Both the second and the third operands have type void; the
4984 result is of type void and is an rvalue.
4986 We must avoid calling force_rvalue for expressions of type
4987 "void" because it will complain that their value is being
4988 used. */
4991 {
4993 {
4997 }
5000 }
5003 {
5005 {
5009 }
5012 }
5015 else
5016 {
5018 {
5021 "second operand to the conditional operator "
5022 "is of type %<void%>, but the third operand is "
5024 else
5026 "third operand to the conditional operator "
5027 "is of type %<void%>, but the second operand is "
5029 }
5031 }
5035 }
5036 /* [expr.cond]
5038 Otherwise, if the second and third operand have different types,
5039 and either has (possibly cv-qualified) class type, or if both are
5040 glvalues of the same value category and the same type except for
5041 cv-qualification, an attempt is made to convert each of those operands
5042 to the type of the other. */
5046 arg3_type)
5049 {
5054 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5060 /* [expr.cond]
5062 If both can be converted, or one can be converted but the
5063 conversion is ambiguous, the program is ill-formed. If
5064 neither can be converted, the operands are left unchanged and
5065 further checking is performed as described below. If exactly
5066 one conversion is possible, that conversion is applied to the
5067 chosen operand and the converted operand is used in place of
5068 the original operand for the remainder of this section. */
5073 {
5075 {
5082 else
5084 }
5086 }
5088 {
5092 /* Even if CONV2 is a valid conversion, the result of the
5093 conversion may be invalid. For example, if ARG3 has type
5094 "volatile X", and X does not have a copy constructor
5095 accepting a "volatile X&", then even if ARG2 can be
5096 converted to X, the conversion will fail. */
5100 }
5102 {
5109 }
5111 /* Free all the conversions we allocated. */
5117 /* If, after the conversion, both operands have class type,
5118 treat the cv-qualification of both operands as if it were the
5119 union of the cv-qualification of the operands.
5121 The standard is not clear about what to do in this
5122 circumstance. For example, if the first operand has type
5123 "const X" and the second operand has a user-defined
5124 conversion to "volatile X", what is the type of the second
5125 operand after this step? Making it be "const X" (matching
5126 the first operand) seems wrong, as that discards the
5127 qualification without actually performing a copy. Leaving it
5128 as "volatile X" seems wrong as that will result in the
5129 conditional expression failing altogether, even though,
5130 according to this step, the one operand could be converted to
5131 the type of the other. */
5139 }
5141 /* [expr.cond]
5143 If the second and third operands are glvalues of the same value
5144 category and have the same type, the result is of that type and
5145 value category. */
5149 {
5154 }
5156 /* [expr.cond]
5158 Otherwise, the result is an rvalue. If the second and third
5159 operand do not have the same type, and either has (possibly
5160 cv-qualified) class type, overload resolution is used to
5161 determine the conversions (if any) to be applied to the operands
5162 (_over.match.oper_, _over.built_). */
5166 {
5171 /* Rearrange the arguments so that add_builtin_candidate only has
5172 to know about two args. In build_builtin_candidate, the
5173 arguments are unscrambled. */
5178 COND_EXPR,
5179 NOP_EXPR,
5181 args,
5184 /* [expr.cond]
5186 If the overload resolution fails, the program is
5187 ill-formed. */
5190 {
5195 }
5198 {
5200 {
5203 }
5205 }
5207 /* [expr.cond]
5209 Otherwise, the conversions thus determined are applied, and
5210 the converted operands are used in place of the original
5211 operands for the remainder of this section. */
5220 }
5222 /* [expr.cond]
5224 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5225 and function-to-pointer (_conv.func_) standard conversions are
5226 performed on the second and third operands.
5228 We need to force the lvalue-to-rvalue conversion here for class types,
5229 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5230 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5231 regions. */
5244 /* [expr.cond]
5246 After those conversions, one of the following shall hold:
5248 --The second and third operands have the same type; the result is of
5249 that type. */
5252 /* [expr.cond]
5254 --The second and third operands have arithmetic or enumeration
5255 type; the usual arithmetic conversions are performed to bring
5256 them to a common type, and the result is of that type. */
5261 {
5262 /* In this case, there is always a common type. */
5264 arg3_type);
5267 "implicit conversion from %qH to %qI to "
5269 loc);
5273 {
5277 /* Two enumerators from the same enumeration can have different
5283 }
5290 {
5294 }
5298 }
5299 /* [expr.cond]
5301 --The second and third operands have pointer type, or one has
5302 pointer type and the other is a null pointer constant; pointer
5303 conversions (_conv.ptr_) and qualification conversions
5304 (_conv.qual_) are performed to bring them to their composite
5305 pointer type (_expr.rel_). The result is of the composite
5306 pointer type.
5308 --The second and third operands have pointer to member type, or
5309 one has pointer to member type and the other is a null pointer
5310 constant; pointer to member conversions (_conv.mem_) and
5311 qualification conversions (_conv.qual_) are performed to bring
5312 them to a common type, whose cv-qualification shall match the
5313 cv-qualification of either the second or the third operand.
5314 The result is of the common type. */
5322 {
5325 complain);
5330 }
5333 {
5338 }
5343 valid_operands:
5346 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5347 warn here, because the COND_EXPR will be turned into ARG2. */
5353 /* We can't use result_type below, as fold might have returned a
5354 throw_expr. */
5357 {
5358 /* Expand both sides into the same slot, hopefully the target of
5359 the ?: expression. We used to check for TARGET_EXPRs here,
5360 but now we sometimes wrap them in NOP_EXPRs so the test would
5361 fail. */
5364 /* If this expression is an rvalue, but might be mistaken for an
5365 lvalue, we must add a NON_LVALUE_EXPR. */
5367 }
5368 else
5372 }
5374 /* Wrapper for above. */
5376 tree
5378 tsubst_flags_t complain)
5379 {
5380 tree ret;
5385 }
5387 /* OPERAND is an operand to an expression. Perform necessary steps
5388 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5389 returned. */
5391 static tree
5393 {
5395 {
5398 /* Make sure the template type is instantiated now. */
5400 }
5403 }
5405 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5406 OVERLOAD) to the CANDIDATES, returning an updated list of
5407 CANDIDATES. The ARGS are the arguments provided to the call;
5408 if FIRST_ARG is non-null it is the implicit object argument,
5409 otherwise the first element of ARGS is used if needed. The
5410 EXPLICIT_TARGS are explicit template arguments provided.
5411 TEMPLATE_ONLY is true if only template functions should be
5412 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5413 add_function_candidate. */
5415 static void
5417 tree return_type,
5422 tsubst_flags_t complain)
5423 {
5424 tree ctype;
5428 unification_kind_t strict;
5433 /* Precalculate special handling of constructors and conversion ops. */
5436 {
5440 /* We're doing return_type(x). */
5442 else
5443 /* We're doing x.operator return_type(). */
5445 /* [over.match.funcs] For conversion functions, the function
5446 is considered to be a member of the class of the implicit
5447 object argument for the purpose of defining the type of
5448 the implicit object parameter. */
5450 }
5451 else
5452 {
5454 {
5456 /* For list-initialization we consider explicit constructors
5457 and complain if one is chosen. */
5458 check_converting
5461 }
5462 else
5463 {
5466 }
5469 }
5473 else
5474 /* Delay creating the implicit this parameter until it is needed. */
5478 {
5479 tree fn_first_arg;
5489 /* Figure out which set of arguments to use. */
5491 {
5492 /* If this function is a non-static member and we didn't get an
5493 implicit object argument, move it out of args. */
5495 {
5497 tree arg;
5504 }
5508 }
5509 else
5510 {
5511 /* Otherwise, just use the list of arguments provided. */
5514 }
5518 fn,
5519 ctype,
5520 explicit_targs,
5521 fn_first_arg,
5522 fn_args,
5523 return_type,
5524 access_path,
5525 conversion_path,
5526 flags,
5527 strict,
5528 complain);
5531 fn,
5532 ctype,
5533 fn_first_arg,
5534 fn_args,
5535 access_path,
5536 conversion_path,
5537 flags,
5538 complain);
5539 }
5540 }
5542 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5543 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5545 static int
5547 {
5549 {
5550 // 5. b @= a
5554 // 6. a[b]
5558 // 1. a.b
5559 // Not overloadable (yet).
5560 // 2. a->b
5561 // Only one argument.
5562 // 3. a->*b
5564 // 7. a << b
5566 // 8. a >> b
5572 }
5573 }
5575 static tree
5578 {
5581 tree fnname;
5599 {
5603 }
5604 else
5611 {
5616 /* Use build_op_new_call and build_op_delete_call instead. */
5620 /* Use build_op_call instead. */
5627 /* These are saved for the sake of warn_logical_operator. */
5637 /* These are saved for the sake of maybe_warn_bool_compare. */
5642 /* =, ->, [], () must be non-static member functions. */
5646 /* FALLTHRU */
5654 }
5660 /* Use build_conditional_expr instead. */
5676 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5679 /* Add namespace-scope operators to the list of functions to
5680 consider. */
5682 {
5688 }
5694 /* Add class-member operators to the candidate set. */
5696 {
5697 tree fns;
5701 {
5704 }
5712 }
5713 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5714 only non-member functions that have type T1 or reference to
5715 cv-qualified-opt T1 for the first argument, if the first argument
5716 has an enumeration type, or T2 or reference to cv-qualified-opt
5717 T2 for the second argument, if the second argument has an
5718 enumeration type. Filter out those that don't match. */
5720 {
5724 {
5734 {
5740 && (same_type_ignoring_top_level_qualifiers_p
5745 }
5747 /* No argument has an appropriate type, so remove this
5748 candidate function from the list. */
5750 {
5753 }
5754 }
5755 }
5761 {
5764 /* For these, the built-in candidates set is empty
5765 [over.match.oper]/3. We don't want non-strict matches
5766 because exact matches are always possible with built-in
5767 operators. The built-in candidate set for COMPONENT_REF
5768 would be empty too, but since there are no such built-in
5769 operators, we accept non-strict matches for them. */
5776 }
5780 {
5782 {
5785 /* Don't try anything fancy if we're not allowed to produce
5786 errors. */
5790 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5791 distinguish between prefix and postfix ++ and
5792 operator++() was used for both, so we allow this with
5793 -fpermissive. */
5794 else
5795 {
5801 }
5808 else
5814 /* The caller will deal with these. */
5824 {
5825 /* If one of the arguments of the operator represents
5826 an invalid use of member function pointer, try to report
5827 a meaningful error ... */
5832 else
5833 {
5834 /* ... Otherwise, report the more generic
5835 "no matching operator found" error */
5838 }
5839 }
5842 }
5843 }
5844 else
5845 {
5848 {
5850 {
5853 }
5855 }
5857 {
5863 else
5869 {
5874 /* This prevents build_new_function_call from discarding this
5875 function during instantiation of the enclosing template. */
5878 /* Specify evaluation order as per P0145R2. */
5881 {
5892 }
5893 }
5894 }
5895 else
5896 {
5897 /* Give any warnings we noticed during overload resolution. */
5899 {
5903 }
5905 /* Check for comparison of different enum types. */
5907 {
5919 {
5923 }
5927 }
5929 /* We need to strip any leading REF_BIND so that bitfields
5930 don't cause errors. This should not remove any important
5931 conversions, because builtins don't apply to class
5932 objects directly. */
5939 {
5943 else
5946 /* We need to call warn_logical_operator before
5947 converting arg2 to a boolean_type, but after
5948 decaying an enumerator to its value. */
5955 }
5957 {
5962 }
5964 }
5965 }
5967 user_defined_result_ready:
5969 /* Free all the conversions we allocated. */
5975 builtin:
5977 {
5992 /* Fall through. */
6005 /* Fall through. */
6038 complain),
6041 /* The caller will deal with these. */
6049 }
6051 }
6053 /* Wrapper for above. */
6055 tree
6059 {
6060 tree ret;
6066 }
6068 /* CALL was returned by some call-building function; extract the actual
6069 CALL_EXPR from any bits that have been tacked on, e.g. by
6070 convert_from_reference. */
6072 tree
6074 {
6085 }
6087 /* Returns true if FN has two parameters, of which the second has type
6088 size_t. */
6090 static bool
6092 {
6104 }
6106 /* True if T, an allocation function, has std::align_val_t as its second
6107 argument. */
6109 bool
6111 {
6117 }
6119 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6120 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6121 std::align_val_t. */
6123 static bool
6125 {
6129 /* A template instance is never a usual deallocation function,
6130 regardless of its signature. */
6146 }
6148 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6149 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6151 bool
6153 {
6154 /* A template instance is never a usual deallocation function,
6155 regardless of its signature. */
6160 /* If a class T has a member deallocation function named operator delete
6161 with exactly one parameter, then that function is a usual
6162 (non-placement) deallocation function. If class T does not declare
6163 such an operator delete but does declare a member deallocation
6164 function named operator delete with exactly two parameters, the second
6165 of which has type std::size_t (18.2), then this function is a usual
6166 deallocation function. */
6178 }
6180 /* Build a call to operator delete. This has to be handled very specially,
6181 because the restrictions on what signatures match are different from all
6182 other call instances. For a normal delete, only a delete taking (void *)
6183 or (void *, size_t) is accepted. For a placement delete, only an exact
6184 match with the placement new is accepted.
6186 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6187 ADDR is the pointer to be deleted.
6188 SIZE is the size of the memory block to be deleted.
6189 GLOBAL_P is true if the delete-expression should not consider
6190 class-specific delete operators.
6191 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6193 If this call to "operator delete" is being generated as part to
6194 deallocate memory allocated via a new-expression (as per [expr.new]
6195 which requires that if the initialization throws an exception then
6196 we call a deallocation function), then ALLOC_FN is the allocation
6197 function. */
6199 tree
6203 {
6217 /* In [class.free]
6219 If the result of the lookup is ambiguous or inaccessible, or if
6220 the lookup selects a placement deallocation function, the
6221 program is ill-formed.
6223 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6224 {
6228 }
6229 else
6235 /* Strip const and volatile from addr. */
6239 {
6240 /* "A declaration of a placement deallocation function matches the
6241 declaration of a placement allocation function if it has the same
6242 number of parameters and, after parameter transformations (8.3.5),
6243 all parameter types except the first are identical."
6245 So we build up the function type we want and ask instantiate_type
6246 to get it for us. */
6257 /* "If the lookup finds the two-parameter form of a usual deallocation
6258 function (3.7.4.2) and that function, considered as a placement
6259 deallocation function, would have been selected as a match for the
6260 allocation function, the program is ill-formed." */
6262 {
6270 /* But if the class has an operator delete (void *), then that is
6271 the usual deallocation function, so we shouldn't complain
6272 about using the operator delete (void *, size_t). */
6276 {
6281 }
6282 /* Before C++14 a two-parameter global deallocation function is
6283 always a placement deallocation function, but warn if
6284 -Wc++14-compat. */
6286 {
6291 }
6294 {
6296 {
6297 /* Only mention C++14 for namespace-scope delete. */
6300 else
6302 "%qD is a usual (non-placement) deallocation "
6304 }
6305 }
6306 else
6308 ok:;
6309 }
6310 }
6311 else
6312 /* "Any non-placement deallocation function matches a non-placement
6313 allocation function. If the lookup finds a single matching
6314 deallocation function, that function will be called; otherwise, no
6315 deallocation function will be called." */
6317 {
6320 {
6322 {
6325 }
6327 /* -- If the type has new-extended alignment, a function with a
6328 parameter of type std::align_val_t is preferred; otherwise a
6329 function without such a parameter is preferred. If exactly one
6330 preferred function is found, that function is selected and the
6331 selection process terminates. If more than one preferred
6332 function is found, all non-preferred functions are eliminated
6333 from further consideration. */
6335 {
6341 {
6345 }
6346 }
6348 /* -- If the deallocation functions have class scope, the one
6349 without a parameter of type std::size_t is selected. */
6354 /* -- If the type is complete and if, for the second alternative
6355 (delete array) only, the operand is a pointer to a class type
6356 with a non-trivial destructor or a (possibly multi-dimensional)
6357 array thereof, the function with a parameter of type std::size_t
6358 is selected.
6360 -- Otherwise, it is unspecified whether a deallocation function
6361 with a parameter of type std::size_t is selected. */
6362 else
6363 {
6367 /* We need a cookie to determine the array size. */
6369 }
6375 }
6376 }
6378 /* If we have a matching function, call it. */
6380 {
6383 /* If the FN is a member function, make sure that it is
6384 accessible. */
6387 complain);
6389 /* Core issue 901: It's ok to new a type with deleted delete. */
6394 {
6395 /* The placement args might not be suitable for overload
6396 resolution at this point, so build the call directly. */
6406 }
6407 else
6408 {
6409 tree ret;
6415 {
6418 }
6422 }
6423 }
6425 /* [expr.new]
6427 If no unambiguous matching deallocation function can be found,
6428 propagating the exception does not cause the object's memory to
6429 be freed. */
6431 {
6435 alloc_fn);
6437 }
6443 }
6445 /* If the current scope isn't allowed to access DECL along
6446 BASETYPE_PATH, give an error. The most derived class in
6447 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6448 the declaration to use in the error diagnostic. */
6450 bool
6453 {
6458 {
6459 /* 7.3.3/18: The additional constructors are accessible if they would be
6460 accessible when used to construct an object of the corresponding base
6461 class. */
6465 }
6468 {
6470 {
6474 {
6480 }
6482 {
6488 }
6489 else
6490 {
6495 }
6496 }
6498 }
6501 }
6503 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6504 bitwise or of LOOKUP_* values. If any errors are warnings are
6505 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6506 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6507 to NULL. */
6509 static tree
6512 {
6518 /* If the source is a packed field, calling the copy constructor will require
6519 binding the field to the reference parameter to the copy constructor, and
6520 we'll end up with an infinite loop. If we can use a bitwise copy, then
6521 do that now. */
6537 }
6539 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6540 EXPR is implicitly converted to type TOTYPE.
6541 FN and ARGNUM are used for diagnostics. */
6543 static void
6545 {
6546 /* Issue warnings about peculiar, but valid, uses of NULL. */
6549 {
6550 source_location loc =
6557 else
6560 }
6562 /* Issue warnings if "false" is converted to a NULL pointer */
6565 {
6568 "converting %<false%> to pointer type for argument %P "
6570 else
6573 }
6574 }
6576 /* We gave a diagnostic during a conversion. If this was in the second
6577 standard conversion sequence of a user-defined conversion sequence, say
6578 which user-defined conversion. */
6580 static void
6582 {
6586 {
6590 }
6591 }
6593 /* Perform the conversions in CONVS on the expression EXPR. FN and
6594 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6595 indicates the `this' argument of a method. INNER is nonzero when
6596 being called to continue a conversion chain. It is negative when a
6597 reference binding will be applied, positive otherwise. If
6598 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6599 conversions will be emitted if appropriate. If C_CAST_P is true,
6600 this conversion is coming from a C-style cast; in that case,
6601 conversions to inaccessible bases are permitted. */
6603 static tree
6607 {
6609 diagnostic_t diag_kind;
6625 {
6629 /* Give a helpful error if this is bad because of excess braces. */
6634 {
6640 }
6642 /* Give a helpful error if this is bad because a conversion to bool
6643 from std::nullptr_t requires direct-initialization. */
6651 {
6653 {
6656 totype);
6662 complain);
6666 complain);
6667 else
6673 }
6675 {
6679 complain);
6681 }
6686 complain);
6689 }
6698 }
6704 {
6706 {
6710 /* When converting from an init list we consider explicit
6711 constructors, but actually trying to call one is an error. */
6714 /* Unless this is for direct-list-initialization. */
6716 /* And in C++98 a default constructor can't be explicit. */
6718 {
6724 {
6730 }
6731 else
6734 }
6736 /* If we're initializing from {}, it's value-initialization. */
6740 {
6745 {
6748 }
6750 }
6754 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6755 any more UDCs. */
6757 complain);
6759 /* If this is a constructor or a function returning an aggr type,
6760 we need to build up a TARGET_EXPR. */
6762 {
6765 /* Remember that this was list-initialization. */
6768 }
6771 }
6774 {
6780 else
6782 }
6789 /* We leave bad_p off ck_ambig because overload resolution considers
6790 it valid, it just fails when we try to perform it. So we need to
6791 check complain here, too. */
6793 {
6794 /* Call build_user_type_conversion again for the error. */
6796 complain);
6800 }
6804 {
6805 /* Conversion to std::initializer_list<T>. */
6813 /* Convert all the elements. */
6815 {
6826 }
6827 /* Build up the array. */
6828 elttype = cp_build_qualified_type
6832 /* Take the address explicitly rather than via decay_conversion
6833 to avoid the error about taking the address of a temporary. */
6839 /* Build up the initializer_list object. */
6847 }
6851 {
6860 }
6863 complain);
6870 };
6874 c_cast_p,
6875 complain);
6880 {
6884 {
6886 {
6891 }
6893 }
6898 /* Don't introduce copies when passing arguments along to the inherited
6899 constructor. */
6901 && flag_new_inheriting_ctors
6905 /* Fall through. */
6908 {
6909 /* We are going to bind a reference directly to a base-class
6910 subobject of EXPR. */
6911 /* Build an expression for `*((base*) &expr)'. */
6915 }
6917 /* Copy-initialization where the cv-unqualified version of the source
6918 type is the same class as, or a derived class of, the class of the
6919 destination [is treated as direct-initialization]. [dcl.init] */
6922 /* This conversion is being done in the context of a user-defined
6923 conversion (i.e. the second step of copy-initialization), so
6924 don't allow any more. */
6926 else
6932 /* Copy-list-initialization doesn't actually involve a copy. */
6936 {
6941 }
6946 {
6950 {
6963 else
6970 }
6972 /* If necessary, create a temporary.
6974 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6975 that need temporaries, even when their types are reference
6976 compatible with the type of reference being bound, so the
6977 upcoming call to cp_build_addr_expr doesn't fail. */
6981 {
6982 /* Otherwise, a temporary of type "cv1 T1" is created and
6983 initialized from the initializer expression using the rules
6984 for a non-reference copy-initialization (8.5). */
6993 {
6994 /* If the reference is volatile or non-const, we
6995 cannot create a temporary. */
7002 else
7006 }
7007 /* If the source is a packed field, and we must use a copy
7008 constructor, then building the target expr will require
7009 binding the field to the reference parameter to the
7010 copy constructor, and we'll end up with an infinite
7011 loop. If we can use a bitwise copy, then we'll be
7012 OK. */
7016 {
7020 }
7022 {
7025 }
7027 }
7029 /* Take the address of the thing to which we will bind the
7030 reference. */
7035 /* Convert it to a pointer to the type referred to by the
7036 reference. This will adjust the pointer if a derived to
7037 base conversion is being performed. */
7040 /* Convert the pointer to the desired reference type. */
7042 }
7048 /* ??? Should the address of a transaction-safe pointer point to the TM
7049 clone, and this conversion look up the primary function? */
7053 /* Warn about deprecated conversion if appropriate. */
7069 }
7077 else
7081 }
7083 /* ARG is being passed to a varargs function. Perform any conversions
7084 required. Return the converted value. */
7086 tree
7088 {
7089 tree arg_type;
7092 /* [expr.call]
7094 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7095 standard conversions are performed. */
7098 /* [expr.call]
7100 If the argument has integral or enumeration type that is subject
7101 to the integral promotions (_conv.prom_), or a floating point
7102 type that is subject to the floating point promotion
7103 (_conv.fpprom_), the value of the argument is converted to the
7104 promoted type before the call. */
7109 {
7113 "implicit conversion from %qH to %qI when passing "
7117 }
7121 {
7123 {
7125 complain);
7135 }
7136 else
7138 }
7144 /* In a template (or ill-formed code), we can have an incomplete type
7145 even after require_complete_type_sfinae, in which case we don't know
7146 whether it has trivial copy or not. */
7148 {
7149 /* Build up a real lvalue-to-rvalue conversion in case the
7150 copy constructor is trivial but not callable. */
7154 /* [expr.call] 5.2.2/7:
7155 Passing a potentially-evaluated argument of class type (Clause 9)
7156 with a non-trivial copy constructor or a non-trivial destructor
7157 with no corresponding parameter is conditionally-supported, with
7158 implementation-defined semantics.
7160 We support it as pass-by-invisible-reference, just like a normal
7161 value parameter.
7163 If the call appears in the context of a sizeof expression,
7164 it is not potentially-evaluated. */
7168 {
7171 "passing objects of non-trivially-copyable "
7173 arg_type);
7175 }
7176 }
7179 }
7181 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7183 tree
7185 {
7187 {
7191 }
7201 {
7204 }
7208 {
7209 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7210 it as pass by invisible reference. */
7212 "receiving objects of non-trivially-copyable type %q#T "
7218 }
7222 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7223 know how to handle it. */
7226 }
7228 /* TYPE has been given to va_arg. Apply the default conversions which
7229 would have happened when passed via ellipsis. Return the promoted
7230 type, or the passed type if there is no change. */
7232 tree
7234 {
7235 tree promote;
7237 /* Perform the array-to-pointer and function-to-pointer
7238 conversions. */
7246 }
7248 /* ARG is a default argument expression being passed to a parameter of
7249 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7250 zero-based argument number. Do any required conversions. Return
7251 the converted value. */
7254 void
7258 void
7262 tree
7264 tsubst_flags_t complain)
7265 {
7267 tree t;
7269 /* See through clones. */
7271 /* And inheriting ctors. */
7275 /* Detect recursion. */
7278 {
7282 }
7284 /* If the ARG is an unparsed default argument expression, the
7285 conversion cannot be performed. */
7287 {
7292 }
7299 /* Due to:
7301 [dcl.fct.default]
7303 The names in the expression are bound, and the semantic
7304 constraints are checked, at the point where the default
7305 expressions appears.
7307 we must not perform access checks here. */
7309 /* We must make a copy of ARG, in case subsequent processing
7310 alters any part of it. */
7314 complain);
7321 }
7323 /* Returns the type which will really be used for passing an argument of
7324 type TYPE. */
7326 tree
7328 {
7329 /* Pass classes with copy ctors by invisible reference. */
7331 {
7333 /* There are no other pointers to this temporary. */
7335 }
7343 }
7345 /* Actually perform the appropriate conversion. */
7347 tree
7349 {
7350 tree bitfield_type;
7352 /* If VAL is a bitfield, then -- since it has already been converted
7353 to TYPE -- it cannot have a precision greater than TYPE.
7355 If it has a smaller precision, we must widen it here. For
7356 example, passing "int f:3;" to a function expecting an "int" will
7357 not result in any conversion before this point.
7359 If the precision is the same we must not risk widening. For
7360 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7361 often have type "int", even though the C++ type for the field is
7362 "long long". If the value is being passed to a function
7363 expecting an "int", then no conversions will be required. But,
7364 if we call convert_bitfield_to_declared_type, the bitfield will
7365 be converted to "long long". */
7372 ;
7373 /* Pass classes with copy ctors by invisible reference. */
7382 {
7384 {
7392 "argument of function call might be a candidate "
7394 }
7396 }
7398 }
7400 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7401 which just decay_conversion or no conversions at all should be done.
7402 This is true for some builtins which don't act like normal functions.
7403 Return 2 if no conversions at all should be done, 1 if just
7404 decay_conversion. Return 3 for special treatment of the 3rd argument
7405 for __builtin_*_overflow_p. */
7407 int
7409 {
7415 {
7430 }
7433 }
7435 /* Returns the decl of the dispatcher function if FN is a function version. */
7437 tree
7439 {
7449 {
7453 }
7458 }
7460 /* fn is a function version dispatcher that is marked used. Mark all the
7461 semantically identical function versions it will dispatch as used. */
7463 void
7465 {
7482 /* All semantically identical versions are chained. Traverse and mark each
7483 one of them as used. */
7486 {
7489 }
7490 }
7492 /* Build a call to "the copy constructor" for the type of A, even if it
7493 wouldn't be selected by normal overload resolution. Used for
7494 diagnostics. */
7496 static tree
7498 {
7509 }
7511 /* Return true iff T refers to a base field. */
7513 static bool
7515 {
7524 }
7526 /* We can't elide a copy from a function returning by value to a base
7527 subobject, as the callee might clobber tail padding. Return true iff this
7528 could be that case. */
7530 static bool
7532 {
7533 /* Copy elision only happens with a TARGET_EXPR. */
7537 /* It's safe to elide the copy for a class with no tail padding. */
7540 /* It's safe to elide the copy if we aren't initializing a base object. */
7544 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7549 }
7551 /* Subroutine of the various build_*_call functions. Overload resolution
7552 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7553 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7554 bitmask of various LOOKUP_* flags which apply to the call itself. */
7556 static tree
7558 {
7566 tree val;
7575 /* In a template, there is no need to perform all of the work that
7576 is normally done. We are only interested in the type of the call
7577 expression, i.e., the return type of the function. Any semantic
7578 errors will be deferred until the template is instantiated. */
7580 {
7582 tree return_type;
7593 else
7594 {
7597 tree arg;
7605 }
7615 }
7617 /* Give any warnings we noticed during overload resolution. */
7619 {
7623 }
7625 /* OK, we're actually calling this inherited constructor; set its deletedness
7626 appropriately. We can get away with doing this here because calling is
7627 the only way to refer to a constructor. */
7631 /* Make =delete work with SFINAE. */
7636 {
7637 tree access_fn;
7638 /* If FN is a template function, two cases must be considered.
7639 For example:
7641 struct A {
7642 protected:
7643 template <class T> void f();
7644 };
7645 template <class T> struct B {
7646 protected:
7647 void g();
7648 };
7649 struct C : A, B<int> {
7650 using A::f; // #1
7651 using B<int>::g; // #2
7652 };
7654 In case #1 where `A::f' is a member template, DECL_ACCESS is
7655 recorded in the primary template but not in its specialization.
7656 We check access of FN using its primary template.
7658 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7659 because it is a member of class template B, DECL_ACCESS is
7660 recorded in the specialization `B<int>::g'. We cannot use its
7661 primary template because `B<T>::g' and `B<int>::g' may have
7662 different access. */
7666 else
7671 }
7673 /* If we're checking for implicit delete, don't bother with argument
7674 conversions. */
7676 {
7678 {
7682 }
7686 /* Reject bad conversions now. */
7688 /* else continue to get conversion error. */
7689 }
7691 /* N3276 magic doesn't apply to nested calls. */
7695 /* Find maximum size of vector to hold converted arguments. */
7702 /* The implicit parameters to a constructor are not considered by overload
7703 resolution, and must be of the proper type. */
7705 {
7706 tree object_arg;
7708 {
7711 }
7712 else
7713 {
7716 }
7719 /* We should never try to call the abstract constructor. */
7723 {
7727 }
7728 }
7729 /* Bypass access control for 'this' parameter. */
7731 {
7734 ? first_arg
7737 tree converted_arg;
7738 tree base_binfo;
7741 {
7743 {
7748 }
7749 else
7751 }
7753 /* See if the function member or the whole class type is declared
7754 final and the call can be devirtualized. */
7759 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7760 X is called for an object that is not of type X, or of a type
7761 derived from X, the behavior is undefined.
7763 So we can assume that anything passed as 'this' is non-null, and
7764 optimize accordingly. */
7766 /* Convert to the base in which the function was declared. */
7769 arg,
7772 /* Check that the base class is accessible. */
7775 {
7780 else
7782 }
7783 /* If fn was found by a using declaration, the conversion path
7784 will be to the derived class, not the base declaring fn. We
7785 must convert from derived to base. */
7796 else
7800 }
7805 {
7812 /* If the argument is NULL and used to (implicitly) instantiate a
7813 template function (and bind one of the template arguments to
7814 the type of 'long int'), we don't want to warn about passing NULL
7815 to non-pointer argument.
7816 For example, if we have this template function:
7818 template<typename T> void func(T x) {}
7820 we want to warn (when -Wconversion is enabled) in this case:
7822 void foo() {
7823 func<int>(NULL);
7824 }
7826 but not in this case:
7828 void foo() {
7829 func(NULL);
7830 }
7831 */
7838 /* Warn about initializer_list deduction that isn't currently in the
7839 working draft. */
7841 && flag_deduce_init_list
7845 {
7858 {
7866 }
7867 }
7869 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7870 knows not to allow any more UDCs. This needs to happen after we
7871 process cand->warnings. */
7880 arg_complain);
7885 else
7887 }
7889 /* Default arguments */
7891 {
7897 complain);
7898 }
7900 /* Ellipsis */
7903 {
7906 {
7907 /* Do no conversions for certain magic varargs. */
7911 }
7913 /* For other magic varargs only do decay_conversion. */
7918 {
7919 /* Avoid infinite recursion trying to call A(...). */
7921 /* Try to call the actual copy constructor for a good error. */
7924 }
7925 else
7930 }
7935 /* Avoid to do argument-transformation, if warnings for format, and for
7936 nonnull are disabled. Just in case that at least one of them is active
7937 the check_function_arguments function might warn about something. */
7941 || warn_format
7942 || warn_suggest_attribute_format
7944 {
7952 }
7955 {
7956 /* Check for passing ellipsis arguments to an inherited constructor. We
7957 could handle this by open-coding the inherited constructor rather than
7958 defining it, but let's not bother now. */
7962 {
7964 {
7968 }
7970 }
7972 /* A base constructor inheriting from a virtual base doesn't get the
7973 inherited arguments, just this and __vtt. */
7976 }
7978 /* Avoid actually calling copy constructors and copy assignment operators,
7979 if possible. */
7986 /* It's unsafe to elide the constructor when handling
7987 a noexcept-expression, it may evaluate to the wrong
7988 value (c++/53025). */
7990 {
7991 tree targ;
7993 tree fa;
7996 /* Pull out the real argument, disregarding const-correctness. */
7998 /* Strip the reference binding for the constructor parameter. */
8002 /* But don't strip any other reference bindings; binding a temporary to a
8003 reference prevents copy elision. */
8009 {
8014 }
8015 else
8020 else
8023 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8024 subobject. */
8027 /* It's from binding the ref parm to a packed field. */
8030 /* See unsafe_copy_elision_p. */
8033 /* [class.copy]: the copy constructor is implicitly defined even if
8034 the implementation elided its use. */
8036 {
8040 }
8042 /* If we're creating a temp and we already have one, don't create a
8043 new one. If we're not creating a temp but we get one, use
8044 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8045 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8046 temp or an INIT_EXPR otherwise. */
8049 {
8054 }
8057 {
8059 RO_NULL,
8060 complain));
8064 }
8065 }
8069 {
8070 tree to = cp_stabilize_reference
8077 {
8078 /* Avoid copying empty classes. */
8081 }
8083 {
8086 /* Handle NSDMI that refer to the object being initialized. */
8088 }
8089 else
8090 {
8091 /* We must only copy the non-tail padding parts. */
8099 build_index_type
8108 }
8111 }
8114 {
8118 {
8121 else
8123 }
8124 }
8126 /* For calls to a multi-versioned function, overload resolution
8127 returns the function with the highest target priority, that is,
8128 the version that will checked for dispatching first. If this
8129 version is inlinable, a direct call to this version can be made
8130 otherwise the call should go through the dispatcher. */
8135 {
8141 }
8148 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8149 virtual functions can't be constexpr. */
8151 {
8152 tree t;
8159 complain);
8165 }
8166 else
8167 {
8171 }
8177 {
8179 /* build_new_op_1 will clear this when appropriate. */
8181 }
8183 {
8187 }
8189 }
8191 /* Return the DECL of the first non-public data member of class TYPE
8192 or null if none can be found. */
8194 static tree
8196 {
8201 {
8208 }
8214 {
8219 }
8222 }
8224 /* Return true if all copy and move assignment operator overloads for
8225 class TYPE are trivial and at least one of them is not deleted and,
8226 when ACCESS is set, accessible. Return false otherwise. Set
8227 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8228 copy or move assignment. */
8230 static bool
8232 {
8238 /* Iterate over overloads of the assignment operator, checking
8239 accessible copy assignments for triviality. */
8242 {
8245 /* Skip operators that aren't copy assignments. */
8252 /* Skip template assignment operators and deleted functions. */
8262 /* Break early when both properties have been determined. */
8265 }
8267 /* Return true if they're all trivial and one of the expressions
8268 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8273 }
8275 /* Return true if all copy and move ctor overloads for class TYPE are
8276 trivial and at least one of them is not deleted and, when ACCESS is
8277 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8278 to true when the TYPE has a (not necessarily trivial) default and copy
8279 (or move) ctor, respectively. */
8281 static bool
8283 {
8289 {
8292 /* Skip template constructors. */
8298 /* Skip ctors other than default, copy, and move. */
8314 /* Break early when both properties have been determined. */
8317 }
8320 }
8322 /* Issue a warning on a call to the built-in function FNDECL if it is
8323 a raw memory write whose destination is not an object of (something
8324 like) trivial or standard layout type with a non-deleted assignment
8325 and copy ctor. Detects const correctness violations, corrupting
8326 references, virtual table pointers, and bypassing non-trivial
8327 assignments. */
8329 static void
8331 {
8332 /* Except for bcopy where it's second, the destination pointer is
8333 the first argument for all functions handled here. Compute
8334 the index of the destination and source arguments. */
8342 /* Remove the outermost (usually implicit) conversion to the void*
8343 argument type. */
8349 /* Determine the type of the pointed-to object and whether it's
8350 a complete class type. */
8356 /* Check to see if the raw memory call is made by a ctor or dtor
8357 with this as the destination argument for the destination type.
8358 If so, be more permissive. */
8363 {
8369 /* A ctor and dtor for a class with no bases and no virtual functions
8370 can do whatever they want. Bail early with no further checking. */
8373 }
8375 /* True if the class is trivial. */
8378 /* Set to true if DESTYPE has an accessible copy assignment. */
8380 /* True if all of the class' overloaded copy assignment operators
8381 are all trivial (and not deleted) and at least one of them is
8382 accessible. */
8385 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8386 respectively. */
8389 /* True if all of the class' overloaded copy constructors are all
8390 trivial (and not deleted) and at least one of them is accessible. */
8393 /* Set FLD to the first private/protected member of the class. */
8396 /* The warning format string. */
8398 /* A suggested alternative to offer instead of the raw memory call.
8399 Empty string when none can be come up with. */
8404 {
8407 {
8408 /* Diagnose setting non-copy-assignable or non-trivial types,
8409 or types with a private member, to (potentially) non-zero
8410 bytes. Since the value of the bytes being written is unknown,
8411 suggest using assignment instead (if one exists). Also warn
8412 for writes into objects for which zero-initialization doesn't
8413 mean all bits clear (pointer-to-member data, where null is all
8414 bits set). Since the value being written is (most likely)
8415 non-zero, simply suggest assignment (but not copy assignment). */
8423 {
8426 "%qD writing to an object of type %#qT with "
8429 }
8435 }
8436 /* Fall through. */
8439 /* Similarly to the above, diagnose clearing non-trivial or non-
8440 standard layout objects, or objects of types with no assignmenmt.
8441 Since the value being written is known to be zero, suggest either
8442 copy assignment, copy ctor, or default ctor as an alternative,
8443 depending on what's available. */
8466 /* Determine the type of the source object. */
8470 /* Since it's impossible to determine wheter the byte copy is
8471 being used in place of assignment to an existing object or
8472 as a substitute for initialization, assume it's the former.
8473 Determine the best alternative to use instead depending on
8474 what's not deleted. */
8495 srctype))
8496 {
8497 /* Warn when copying into a non-trivial object from an object
8498 of a different type other than void or char. */
8500 "%qD copying an object of non-trivial type "
8503 }
8508 srctype))
8509 {
8512 "%qD copying an object of type %#qT with "
8513 "%qs member %qD from an array of %#qT; use "
8516 }
8518 {
8519 /* Finally, warn on partial copies. */
8520 unsigned HOST_WIDE_INT typesize
8527 "a non-trivial type %#qT leaves %wu "
8530 "a non-trivial type %#qT leaves %wu "
8533 }
8550 {
8551 /* Finally, warn on reallocation into insufficient space. */
8553 "%qD moving an object of non-trivial type "
8557 }
8562 }
8568 {
8572 else
8575 }
8579 }
8581 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8582 This function performs no overload resolution, conversion, or other
8583 high-level operations. */
8585 tree
8587 tsubst_flags_t complain)
8588 {
8589 tree fndecl;
8591 /* Remember roughly where this call is. */
8598 /* Check that arguments to builtin functions match the expectations. */
8602 {
8605 /* We need to take care that values to BUILT_IN_NORMAL
8606 are reduced. */
8614 /* Warn if the built-in writes to an object of a non-trivial type. */
8617 }
8619 /* If it is a built-in array notation function, then the return type of
8620 the function is the element type of the array passed in as array
8621 notation (i.e. the first parameter of the function). */
8623 {
8632 {
8634 {
8637 }
8638 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8639 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8640 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8641 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8642 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8643 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8644 The pre-defined return-type is the correct one. */
8648 }
8649 }
8654 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8655 function call is either the operand of a decltype-specifier or the
8656 right operand of a comma operator that is the operand of a
8657 decltype-specifier, a temporary object is not introduced for the
8658 prvalue. The type of the prvalue may be incomplete. */
8660 {
8666 {
8669 }
8670 }
8672 }
8674 /* Returns the value to use for the in-charge parameter when making a
8675 call to a function with the indicated NAME.
8677 FIXME:Can't we find a neater way to do this mapping? */
8679 tree
8681 {
8683 {
8687 }
8688 else
8689 {
8695 }
8698 }
8700 /* We've built up a constructor call RET. Complain if it delegates to the
8701 constructor we're currently compiling. */
8703 static void
8705 {
8711 }
8713 /* Build a call to a constructor, destructor, or an assignment
8714 operator for INSTANCE, an expression with class type. NAME
8715 indicates the special member function to call; *ARGS are the
8716 arguments. ARGS may be NULL. This may change ARGS. BINFO
8717 indicates the base of INSTANCE that is to be passed as the `this'
8718 parameter to the member function called.
8720 FLAGS are the LOOKUP_* flags to use when processing the call.
8722 If NAME indicates a complete object constructor, INSTANCE may be
8723 NULL_TREE. In this case, the caller will call build_cplus_new to
8724 store the newly constructed object into a VAR_DECL. */
8726 tree
8729 {
8730 tree fns;
8731 /* The type of the subobject to be constructed or destroyed. */
8732 tree class_type;
8734 tree ret;
8739 {
8740 /* Resolve the name. */
8745 }
8751 /* Handle the special case where INSTANCE is NULL_TREE. */
8754 else
8755 {
8759 /* Convert to the base class, if necessary. */
8762 {
8764 /* For constructors and destructors, either the base is
8765 non-virtual, or it is virtual but we are doing the
8766 conversion from a constructor or destructor for the
8767 complete object. In either case, we can convert
8768 statically. */
8770 else
8771 /* However, for assignment operators, we must convert
8772 dynamically if the base is virtual. */
8775 }
8776 }
8780 /* In C++17, "If the initializer expression is a prvalue and the
8781 cv-unqualified version of the source type is the same class as the class
8782 of the destination, the initializer expression is used to initialize the
8783 destination object." Handle that here to avoid doing overload
8784 resolution. */
8788 {
8791 /* FIXME P0135 doesn't say how to handle direct initialization from a
8792 type with a suitable conversion operator. Let's handle it like
8793 copy-initialization, but allowing explict conversions. */
8796 /* If we're using this to initialize a non-temporary object, don't
8797 require the destructor to be accessible. */
8801 sub_complain,
8802 flags);
8805 && (same_type_ignoring_top_level_qualifiers_p
8807 {
8813 /* Avoid change of behavior on Wunused-var-2.C. */
8816 }
8817 }
8821 /* When making a call to a constructor or destructor for a subobject
8822 that uses virtual base classes, pass down a pointer to a VTT for
8823 the subobject. */
8827 {
8828 tree vtt;
8829 tree sub_vtt;
8831 /* If the current function is a complete object constructor
8832 or destructor, then we fetch the VTT directly.
8833 Otherwise, we look it up using the VTT we were given. */
8841 else
8845 {
8848 }
8851 }
8856 complain);
8867 }
8869 /* Return the NAME, as a C string. The NAME indicates a function that
8870 is a member of TYPE. *FREE_P is set to true if the caller must
8871 free the memory returned.
8873 Rather than go through all of this, we should simply set the names
8874 of constructors and destructors appropriately, and dispense with
8875 ctor_identifier, dtor_identifier, etc. */
8879 {
8882 /* Assume that we will not allocate memory. */
8884 /* Constructors and destructors are special. */
8886 {
8887 pretty_name
8889 /* For a destructor, add the '~'. */
8891 {
8893 /* Remember that we need to free the memory allocated. */
8895 }
8896 }
8898 {
8901 TFF_PLAIN_IDENTIFIER),
8902 NULL);
8903 /* Remember that we need to free the memory allocated. */
8905 }
8906 else
8910 }
8912 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8913 be set, upon return, to the function called. ARGS may be NULL.
8914 This may change ARGS. */
8916 static tree
8920 {
8925 tree optype;
8927 tree name;
8930 tree call;
8931 tree fn;
8934 tree orig_instance;
8935 tree orig_fns;
8941 /* We don't know what function we're going to call, yet. */
8950 {
8954 }
8959 /* Dismantle the baselink to collect all the information we need. */
8967 {
8971 }
8982 {
8987 }
8990 /* Under DR 147 A::A() is an invalid constructor call,
8991 not a functional cast. */
8993 {
9004 complain);
9006 }
9008 /* Process the argument list. */
9010 {
9014 }
9016 /* Consider the object argument to be used even if we end up selecting a
9017 static member function. */
9021 /* Figure out whether to skip the first argument for the error
9022 message we will display to users if an error occurs. We don't
9023 want to display any compiler-generated arguments. The "this"
9024 pointer hasn't been added yet. However, we must remove the VTT
9025 pointer if this is a call to a base-class constructor or
9026 destructor. */
9029 {
9030 /* Callers should explicitly indicate whether they want to ctor
9031 the complete object or just the part without virtual bases. */
9034 /* Remove the VTT pointer, if present. */
9039 /* It's OK to call destructors and constructors on cv-qualified
9040 objects. Therefore, convert the INSTANCE to the unqualified
9041 type, if necessary. */
9043 {
9047 }
9048 }
9049 else
9052 /* For the overload resolution we need to find the actual `this`
9053 that would be captured if the call turns out to be to a
9054 non-static member function. Do not actually capture it at this
9055 point. */
9057 /* Constructors don't use the enclosing 'this'. */
9059 else
9062 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9065 /* The number of arguments artificial parms in ARGS; we subtract one because
9066 there's no 'this' in ARGS. */
9069 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9070 initializer, not T({ }). */
9074 {
9081 /* If the initializer list has no elements and T is a class type with
9082 a default constructor, the object is value-initialized. Handle
9083 this here so we don't need to handle it wherever we use
9084 build_special_member_call. */
9087 /* For a user-provided default constructor, use the normal
9088 mechanisms so that protected access works. */
9093 /* If BASETYPE is an aggregate, we need to do aggregate
9094 initialization. */
9096 {
9099 }
9102 {
9108 }
9110 /* Otherwise go ahead with overload resolution. */
9115 }
9116 else
9125 {
9127 {
9134 else
9135 {
9140 {
9143 }
9151 }
9153 }
9155 }
9156 else
9157 {
9160 {
9163 tree arglist;
9166 {
9174 else
9180 }
9182 }
9183 else
9184 {
9192 {
9193 /* This is not an error, it is runtime undefined
9194 behavior. */
9203 fn);
9204 }
9209 {
9214 {
9215 /* We captured 'this' in the current lambda now that
9216 we know we really need it. */
9218 }
9220 /* We can't tell until instantiation time whether we can use
9222 else
9223 {
9226 fn);
9228 }
9229 }
9232 {
9233 /* Optimize away vtable lookup if we know that this
9234 function can't be overridden. We need to check if
9235 the context and the type where we found fn are the same,
9236 actually FN might be defined in a different class
9237 type because of a using-declaration. In this case, we
9238 do not want to perform a non-virtual call. */
9240 && same_type_ignoring_top_level_qualifiers_p
9246 /* Now we know what function is being called. */
9249 /* Build the actual CALL_EXPR. */
9251 /* In an expression of the form `a->f()' where `f' turns
9252 out to be a static member function, `a' is
9253 none-the-less evaluated. */
9262 /* An explicit call of the form "x->~X()" has type
9263 "void". However, on platforms where destructors
9264 return "this" (i.e., those where
9265 targetm.cxx.cdtor_returns_this is true), such calls
9266 will appear to have a return value of pointer type
9267 to the low-level call machinery. We do not want to
9268 change the low-level machinery, since we want to be
9269 able to optimize "delete f()" on such platforms as
9270 "operator delete(~X(f()))" (rather than generating
9271 "t = f(), ~X(t), operator delete (t)"). */
9273 }
9274 }
9275 }
9278 {
9284 {
9287 }
9290 call = (build_min_non_dep_call_vec
9294 orig_args));
9299 }
9301 /* Free all the conversions we allocated. */
9308 }
9310 /* Wrapper for above. */
9312 tree
9316 {
9317 tree ret;
9323 }
9325 /* Returns true iff standard conversion sequence ICS1 is a proper
9326 subsequence of ICS2. */
9328 static bool
9330 {
9331 /* We can assume that a conversion of the same code
9332 between the same types indicates a subsequence since we only get
9333 here if the types we are converting from are the same. */
9340 {
9350 /* At this point, ICS1 cannot be a proper subsequence of
9351 ICS2. We can get a USER_CONV when we are comparing the
9352 second standard conversion sequence of two user conversion
9353 sequences. */
9368 }
9369 }
9371 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9372 be any _TYPE nodes. */
9374 bool
9376 {
9380 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9381 considers every class derived from itself. */
9384 }
9386 /* We build the ICS for an implicit object parameter as a pointer
9387 conversion sequence. However, such a sequence should be compared
9388 as if it were a reference conversion sequence. If ICS is the
9389 implicit conversion sequence for an implicit object parameter,
9390 modify it accordingly. */
9392 static void
9394 {
9396 {
9397 /* [over.match.funcs]
9399 For non-static member functions, the type of the
9400 implicit object parameter is "reference to cv X"
9401 where X is the class of which the function is a
9402 member and cv is the cv-qualification on the member
9403 function declaration. */
9405 tree reference_type;
9407 /* The `this' parameter is a pointer to a class type. Make the
9408 implicit conversion talk about a reference to that same class
9409 type. */
9422 }
9423 }
9425 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9426 and return the initial reference binding conversion. Otherwise,
9427 leave *ICS unchanged and return NULL. */
9431 {
9433 {
9438 }
9441 }
9443 /* Compare two implicit conversion sequences according to the rules set out in
9444 [over.ics.rank]. Return values:
9446 1: ics1 is better than ics2
9447 -1: ics2 is better than ics1
9448 0: ics1 and ics2 are indistinguishable */
9450 static int
9452 {
9453 tree from_type1;
9454 tree from_type2;
9455 tree to_type1;
9456 tree to_type2;
9463 /* REF_BINDING is nonzero if the result of the conversion sequence
9464 is a reference type. In that case REF_CONV is the reference
9465 binding conversion. */
9469 /* Compare badness before stripping the reference conversion. */
9475 /* Handle implicit object parameters. */
9479 /* Handle reference parameters. */
9483 /* List-initialization sequence L1 is a better conversion sequence than
9484 list-initialization sequence L2 if L1 converts to
9485 std::initializer_list<X> for some X and L2 does not. */
9491 /* [over.ics.rank]
9493 When comparing the basic forms of implicit conversion sequences (as
9494 defined in _over.best.ics_)
9496 --a standard conversion sequence (_over.ics.scs_) is a better
9497 conversion sequence than a user-defined conversion sequence
9498 or an ellipsis conversion sequence, and
9500 --a user-defined conversion sequence (_over.ics.user_) is a
9501 better conversion sequence than an ellipsis conversion sequence
9502 (_over.ics.ellipsis_). */
9503 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9504 mismatch. If both ICS are bad, we try to make a decision based on
9505 what would have happened if they'd been good. This is not an
9506 extension, we'll still give an error when we build up the call; this
9507 just helps us give a more helpful error message. */
9517 /* Both conversions are ellipsis conversions. */
9520 /* User-defined conversion sequence U1 is a better conversion sequence
9521 than another user-defined conversion sequence U2 if they contain the
9522 same user-defined conversion operator or constructor and if the sec-
9523 ond standard conversion sequence of U1 is better than the second
9524 standard conversion sequence of U2. */
9526 /* Handle list-conversion with the same code even though it isn't always
9527 ranked as a user-defined conversion and it doesn't have a second
9528 standard conversion sequence; it will still have the desired effect.
9529 Specifically, we need to do the reference binding comparison at the
9530 end of this function. */
9533 {
9549 {
9552 }
9553 else
9554 {
9555 /* For ambiguous or aggregate conversions, use the target type as
9556 a proxy for the conversion function. */
9559 }
9561 /* We can just fall through here, after setting up
9562 FROM_TYPE1 and FROM_TYPE2. */
9565 }
9566 else
9567 {
9571 /* We're dealing with two standard conversion sequences.
9573 [over.ics.rank]
9575 Standard conversion sequence S1 is a better conversion
9576 sequence than standard conversion sequence S2 if
9578 --S1 is a proper subsequence of S2 (comparing the conversion
9579 sequences in the canonical form defined by _over.ics.scs_,
9580 excluding any Lvalue Transformation; the identity
9581 conversion sequence is considered to be a subsequence of
9582 any non-identity conversion sequence */
9593 }
9595 /* One sequence can only be a subsequence of the other if they start with
9596 the same type. They can start with different types when comparing the
9597 second standard conversion sequence in two user-defined conversion
9598 sequences. */
9600 {
9605 }
9607 /* [over.ics.rank]
9609 Or, if not that,
9611 --the rank of S1 is better than the rank of S2 (by the rules
9612 defined below):
9614 Standard conversion sequences are ordered by their ranks: an Exact
9615 Match is a better conversion than a Promotion, which is a better
9616 conversion than a Conversion.
9618 Two conversion sequences with the same rank are indistinguishable
9619 unless one of the following rules applies:
9621 --A conversion that does not a convert a pointer, pointer to member,
9622 or std::nullptr_t to bool is better than one that does.
9624 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9625 so that we do not have to check it explicitly. */
9634 /* A conversion from scalar arithmetic type to complex is worse than a
9635 conversion between scalar arithmetic types. */
9642 {
9645 else
9647 }
9653 {
9658 }
9659 /* The rules for pointers to members A::* are just like the rules
9660 for pointers A*, except opposite: if B is derived from A then
9661 A::* converts to B::*, not vice versa. For that reason, we
9662 switch the from_ and to_ variables here. */
9669 {
9674 }
9679 {
9680 /* This was one of the pointer or pointer-like conversions.
9682 [over.ics.rank]
9684 --If class B is derived directly or indirectly from class A,
9685 conversion of B* to A* is better than conversion of B* to
9686 void*, and conversion of A* to void* is better than
9687 conversion of B* to void*. */
9690 {
9692 deref_from_type2))
9695 deref_from_type1))
9697 }
9700 {
9702 {
9704 {
9706 deref_to_type1))
9708 }
9709 /* We know that DEREF_TO_TYPE1 is `void' here. */
9711 deref_to_type2))
9713 }
9714 }
9717 {
9718 /* [over.ics.rank]
9720 --If class B is derived directly or indirectly from class A
9721 and class C is derived directly or indirectly from B,
9723 --conversion of C* to B* is better than conversion of C* to
9724 A*,
9726 --conversion of B* to A* is better than conversion of C* to
9727 A* */
9729 {
9731 deref_to_type2))
9734 deref_to_type1))
9736 }
9738 {
9740 deref_from_type1))
9743 deref_from_type2))
9745 }
9746 }
9747 }
9750 {
9753 /* [over.ics.rank]
9755 --binding of an expression of type C to a reference of type
9756 B& is better than binding an expression of type C to a
9757 reference of type A&
9759 --conversion of C to B is better than conversion of C to A, */
9762 {
9767 }
9768 }
9771 {
9774 /* [over.ics.rank]
9776 --binding of an expression of type B to a reference of type
9777 A& is better than binding an expression of type C to a
9778 reference of type A&,
9780 --conversion of B to A is better than conversion of C to A */
9783 {
9788 }
9789 }
9791 /* [over.ics.rank]
9793 --S1 and S2 differ only in their qualification conversion and yield
9794 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9795 qualification signature of type T1 is a proper subset of the cv-
9796 qualification signature of type T2 */
9800 {
9804 }
9806 /* [over.ics.rank]
9808 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9809 to an implicit object parameter of a non-static member function
9810 declared without a ref-qualifier, and either S1 binds an lvalue
9811 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9812 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9813 draft standard, 13.3.3.2)
9815 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9816 types to which the references refer are the same type except for
9817 top-level cv-qualifiers, and the type to which the reference
9818 initialized by S2 refers is more cv-qualified than the type to
9819 which the reference initialized by S1 refers.
9821 DR 1328 [over.match.best]: the context is an initialization by
9822 conversion function for direct reference binding (13.3.1.6) of a
9823 reference to function type, the return type of F1 is the same kind of
9824 reference (i.e. lvalue or rvalue) as the reference being initialized,
9825 and the return type of F2 is not. */
9828 {
9835 {
9839 /* Don't prefer a bad conversion that drops cv-quals to a bad
9840 conversion with the wrong rvalueness. */
9844 }
9847 {
9851 {
9852 /* Prefer the one that drops fewer cv-quals. */
9857 }
9859 }
9860 }
9862 /* Neither conversion sequence is better than the other. */
9864 }
9866 /* The source type for this standard conversion sequence. */
9868 static tree
9870 {
9872 {
9877 }
9879 }
9881 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9882 a pointer to LOSER and re-running joust to produce the warning if WINNER
9883 is actually used. */
9885 static void
9887 {
9893 }
9895 /* Compare two candidates for overloading as described in
9896 [over.match.best]. Return values:
9898 1: cand1 is better than cand2
9899 -1: cand2 is better than cand1
9900 0: cand1 and cand2 are indistinguishable */
9902 static int
9904 tsubst_flags_t complain)
9905 {
9911 /* Candidates that involve bad conversions are always worse than those
9912 that don't. */
9918 /* If we have two pseudo-candidates for conversions to the same type,
9919 or two candidates for the same function, arbitrarily pick one. */
9924 /* Prefer a non-deleted function over an implicitly deleted move
9925 constructor or assignment operator. This differs slightly from the
9926 wording for issue 1402 (which says the move op is ignored by overload
9927 resolution), but this way produces better error messages. */
9931 {
9938 }
9940 /* a viable function F1
9941 is defined to be a better function than another viable function F2 if
9942 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9943 ICSi(F2), and then */
9945 /* for some argument j, ICSj(F1) is a better conversion sequence than
9946 ICSj(F2) */
9948 /* For comparing static and non-static member functions, we ignore
9949 the implicit object parameter of the non-static function. The
9950 standard says to pretend that the static function has an object
9951 parm, but that won't work with operator overloading. */
9954 {
9960 /* We're comparing a near-match list constructor and a near-match
9961 non-list constructor. Just treat them as unordered. */
9968 else
9969 {
9972 }
9973 }
9976 {
9982 {
9984 && warn_sign_promo
9996 {
10003 else
10008 {
10012 }
10013 else
10015 }
10018 {
10021 }
10023 }
10024 }
10026 /* warn about confusing overload resolution for user-defined conversions,
10027 either between a constructor and a conversion op, or between two
10028 conversion ops. */
10033 {
10039 else
10042 /* We don't want to complain about `X::operator T1 ()'
10043 beating `X::operator T2 () const', when T2 is a no less
10044 cv-qualified version of T1. */
10047 {
10052 {
10055 }
10058 }
10059 else
10065 {
10072 {
10074 }
10075 }
10076 else
10078 }
10083 /* DR 495 moved this tiebreaker above the template ones. */
10084 /* or, if not that,
10085 the context is an initialization by user-defined conversion (see
10086 _dcl.init_ and _over.match.user_) and the standard conversion
10087 sequence from the return type of F1 to the destination type (i.e.,
10088 the type of the entity being initialized) is a better conversion
10089 sequence than the standard conversion sequence from the return type
10090 of F2 to the destination type. */
10093 {
10097 }
10099 /* or, if not that,
10100 F1 is a non-template function and F2 is a template function
10101 specialization. */
10108 /* or, if not that,
10109 F1 and F2 are template functions and the function template for F1 is
10110 more specialized than the template for F2 according to the partial
10111 ordering rules. */
10114 {
10115 winner = more_specialized_fn
10118 /* [temp.func.order]: The presence of unused ellipsis and default
10119 arguments has no effect on the partial ordering of function
10120 templates. add_function_candidate() will not have
10121 counted the "this" argument for constructors. */
10125 }
10127 // C++ Concepts
10128 // or, if not that, F1 is more constrained than F2.
10130 {
10134 }
10136 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10138 {
10140 /* We distinguish between candidates from an explicit deduction guide and
10141 candidates built from a constructor based on DECL_ARTIFICIAL. */
10148 {
10149 /* Prefer the special copy guide over a declared copy/move
10150 constructor. */
10156 /* Prefer a candidate generated from a non-template constructor. */
10161 }
10162 }
10164 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10165 for all arguments the corresponding parameters of F1 and F2 have the same
10166 type (CWG 2273/2277). */
10171 {
10185 {
10187 {
10192 }
10195 }
10196 }
10198 /* Check whether we can discard a builtin candidate, either because we
10199 have two identical ones or matching builtin and non-builtin candidates.
10201 (Pedantically in the latter case the builtin which matched the user
10202 function should not be added to the overload set, but we spot it here.
10204 [over.match.oper]
10205 ... the builtin candidates include ...
10206 - do not have the same parameter type list as any non-template
10207 non-member candidate. */
10210 {
10216 {
10218 /* Two built-in candidates; arbitrarily pick one. */
10221 /* cand1 is built-in; prefer cand2. */
10223 else
10224 /* cand2 is built-in; prefer cand1. */
10226 }
10227 }
10229 /* For candidates of a multi-versioned function, make the version with
10230 the highest priority win. This version will be checked for dispatching
10231 first. If this version can be inlined into the caller, the front-end
10232 will simply make a direct call to this function. */
10238 {
10244 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10245 is possible that cand1->fn and cand2->fn are function versions but of
10246 different functions. Check types to see if they are versions of the same
10247 function. */
10250 {
10251 /* Always make the version with the higher priority, more
10252 specialized, win. */
10256 else
10258 }
10259 }
10261 /* If the two function declarations represent the same function (this can
10262 happen with declarations in multiple scopes and arg-dependent lookup),
10263 arbitrarily choose one. But first make sure the default args we're
10264 using match. */
10267 {
10274 {
10275 /* Don't crash if the fn is variadic. */
10280 }
10288 {
10291 {
10293 {
10295 {
10297 "default argument mismatch in "
10299 {
10304 }
10305 }
10306 else
10308 }
10309 else
10312 }
10315 }
10318 }
10320 tweak:
10322 /* Extension: If the worst conversion for one candidate is worse than the
10323 worst conversion for the other, take the first. */
10325 {
10330 {
10335 }
10341 {
10342 /* Don't choose a deleted function over ambiguity. */
10346 {
10348 "ISO C++ says that these are ambiguous, even "
10349 "though the worst conversion for the first is better than "
10353 }
10354 else
10357 }
10358 }
10362 }
10364 /* Given a list of candidates for overloading, find the best one, if any.
10365 This algorithm has a worst case of O(2n) (winner is last), and a best
10366 case of O(n/2) (totally ambiguous); much better than a sorting
10367 algorithm. */
10371 {
10376 /* Walk through the list once, comparing each current champ to the next
10377 candidate, knocking out a candidate or two with each comparison. */
10380 {
10384 else
10385 {
10387 {
10392 }
10393 else
10394 {
10397 }
10400 }
10401 }
10403 /* Make sure the champ is better than all the candidates it hasn't yet
10404 been compared to. */
10407 challenger != champ
10410 {
10414 }
10417 }
10419 /* Returns nonzero if things of type FROM can be converted to TO. */
10421 bool
10423 {
10425 /* implicit_conversion only considers user-defined conversions
10426 if it has an expression for the call argument list. */
10430 }
10432 /* Returns nonzero if things of type FROM can be converted to TO with a
10433 standard conversion. */
10435 bool
10437 {
10439 }
10441 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10443 bool
10445 tsubst_flags_t complain)
10446 {
10451 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10453 /* We want to discard any access checks done for this test,
10454 as we might not be in the appropriate access context and
10455 we'll do the check again when we actually perform the
10456 conversion. */
10463 /* Discard the access checks now. */
10465 /* Free all the conversions we allocated. */
10469 }
10471 /* Like can_convert_arg, but allows dubious conversions as well. */
10473 bool
10475 tsubst_flags_t complain)
10476 {
10480 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10482 /* Try to perform the conversion. */
10485 /* Free all the conversions we allocated. */
10489 }
10491 /* Convert EXPR to TYPE. Return the converted expression.
10493 Note that we allow bad conversions here because by the time we get to
10494 this point we are committed to doing the conversion. If we end up
10495 doing a bad conversion, convert_like will complain. */
10497 tree
10500 {
10508 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10516 {
10518 {
10519 /* If expr has unknown type, then it is an overloaded function.
10520 Call instantiate_type to get good error messages. */
10525 else
10528 }
10530 }
10532 {
10533 /* In a template, we are only concerned about determining the
10534 type of non-dependent expressions, so we do not have to
10535 perform the actual conversion. But for initializers, we
10536 need to be able to perform it at instantiation
10537 (or instantiate_non_dependent_expr) time. */
10541 }
10542 else
10545 /* Free all the conversions we allocated. */
10549 }
10551 tree
10553 {
10555 LOOKUP_IMPLICIT);
10556 }
10558 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10559 permitted. If the conversion is valid, the converted expression is
10560 returned. Otherwise, NULL_TREE is returned, except in the case
10561 that TYPE is a class type; in that case, an error is issued. If
10562 C_CAST_P is true, then this direct-initialization is taking
10563 place as part of a static_cast being attempted as part of a C-style
10564 cast. */
10566 tree
10568 tree expr,
10570 tsubst_flags_t complain)
10571 {
10577 /* [dcl.init]
10579 If the destination type is a (possibly cv-qualified) class type:
10581 -- If the initialization is direct-initialization ...,
10582 constructors are considered. ... If no constructor applies, or
10583 the overload resolution is ambiguous, the initialization is
10584 ill-formed. */
10586 {
10592 }
10594 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10598 c_cast_p,
10602 else
10605 c_cast_p,
10606 complain);
10608 /* Free all the conversions we allocated. */
10612 }
10614 /* When initializing a reference that lasts longer than a full-expression,
10615 this special rule applies:
10617 [class.temporary]
10619 The temporary to which the reference is bound or the temporary
10620 that is the complete object to which the reference is bound
10621 persists for the lifetime of the reference.
10623 The temporaries created during the evaluation of the expression
10624 initializing the reference, except the temporary to which the
10625 reference is bound, are destroyed at the end of the
10626 full-expression in which they are created.
10628 In that case, we store the converted expression into a new
10629 VAR_DECL in a new scope.
10631 However, we want to be careful not to create temporaries when
10632 they are not required. For example, given:
10634 struct B {};
10635 struct D : public B {};
10636 D f();
10637 const B& b = f();
10639 there is no need to copy the return value from "f"; we can just
10640 extend its lifetime. Similarly, given:
10642 struct S {};
10643 struct T { operator S(); };
10644 T t;
10645 const S& s = t;
10647 we can extend the lifetime of the return value of the conversion
10648 operator.
10650 The next several functions are involved in this lifetime extension. */
10652 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10653 reference is being bound to a temporary. Create and return a new
10654 VAR_DECL with the indicated TYPE; this variable will store the value to
10655 which the reference is bound. */
10657 tree
10659 {
10662 /* Register the variable. */
10665 {
10666 /* Namespace-scope or local static; give it a mangled name. */
10667 /* FIXME share comdat with decl? */
10678 }
10679 else
10680 /* Create a new cleanup level if necessary. */
10684 }
10686 /* EXPR is the initializer for a variable DECL of reference or
10687 std::initializer_list type. Create, push and return a new VAR_DECL
10688 for the initializer so that it will live as long as DECL. Any
10689 cleanup for the new variable is returned through CLEANUP, and the
10690 code to initialize the new variable is returned through INITP. */
10692 static tree
10695 {
10696 tree init;
10697 tree type;
10698 tree var;
10700 /* Create the temporary variable. */
10704 /* If the rvalue is the result of a function call it will be
10705 a TARGET_EXPR. If it is some other construct (such as a
10706 member access expression where the underlying object is
10707 itself the result of a function call), turn it into a
10708 TARGET_EXPR here. It is important that EXPR be a
10709 TARGET_EXPR below since otherwise the INIT_EXPR will
10710 attempt to make a bitwise copy of EXPR to initialize
10711 VAR. */
10717 {
10721 }
10723 /* Recursively extend temps in this initializer. */
10727 /* Any reference temp has a non-trivial initializer. */
10730 /* If the initializer is constant, put it in DECL_INITIAL so we get
10731 static initialization and use in constant expressions. */
10734 {
10736 {
10737 /* 5.19 says that a constant expression can include an
10738 lvalue-rvalue conversion applied to "a glvalue of literal type
10739 that refers to a non-volatile temporary object initialized
10740 with a constant expression". Rather than try to communicate
10741 that this VAR_DECL is a temporary, just mark it constexpr.
10743 Currently this is only useful for initializer_list temporaries,
10744 since reference vars can't appear in constant expressions. */
10748 }
10751 }
10752 else
10753 /* Create the INIT_EXPR that will initialize the temporary
10754 variable. */
10757 {
10762 else
10763 {
10767 }
10769 /* We must be careful to destroy the temporary only
10770 after its initialization has taken place. If the
10771 initialization throws an exception, then the
10772 destructor should not be run. We cannot simply
10773 transform INIT into something like:
10775 (INIT, ({ CLEANUP_STMT; }))
10777 because emit_local_var always treats the
10778 initializer as a full-expression. Thus, the
10779 destructor would run too early; it would run at the
10780 end of initializing the reference variable, rather
10781 than at the end of the block enclosing the
10782 reference variable.
10784 The solution is to pass back a cleanup expression
10785 which the caller is responsible for attaching to
10786 the statement tree. */
10787 }
10788 else
10789 {
10792 {
10795 tls_aggregates);
10796 else
10798 static_aggregates);
10799 }
10800 else
10801 /* Check whether the dtor is callable. */
10803 }
10804 /* Avoid -Wunused-variable warning (c++/38958). */
10811 }
10813 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10814 initializing a variable of that TYPE. */
10816 tree
10819 {
10827 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10833 {
10835 {
10844 else
10848 }
10850 }
10853 /* Perform the conversion. */
10856 /* We gave an error in build_user_type_conversion_1. */
10858 else
10861 /* Free all the conversions we allocated. */
10865 }
10867 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10868 which is bound either to a reference or a std::initializer_list. */
10870 static tree
10872 {
10877 {
10881 }
10884 /* Deal with binding to a subobject. */
10888 {
10896 }
10898 }
10900 /* INIT is part of the initializer for DECL. If there are any
10901 reference or initializer lists being initialized, extend their
10902 lifetime to match that of DECL. */
10904 tree
10906 {
10912 else
10913 {
10918 {
10920 {
10921 /* The temporary array underlying a std::initializer_list
10922 is handled like a reference temporary. */
10926 }
10927 else
10928 {
10934 }
10938 }
10939 }
10942 }
10944 /* Returns true iff an initializer for TYPE could contain temporaries that
10945 need to be extended because they are bound to references or
10946 std::initializer_list. */
10948 bool
10950 {
10955 {
10962 }
10964 }
10966 /* Returns true iff TYPE is some variant of std::initializer_list. */
10968 bool
10970 {
10975 /* Look through typedefs. */
10980 }
10982 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10983 will accept an argument list of a single std::initializer_list<T>. */
10985 bool
10987 {
10989 tree arg;
11001 /* There are more non-defaulted parms. */
11005 }