| blob | 8cdda6200e18685556423403fe7e632b1037e7fd |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987-2015 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_tsafe,
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);
150 #define convert_like(CONV, EXPR, COMPLAIN) \
151 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
154 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
155 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
163 tsubst_flags_t);
175 static void add_builtin_candidates
178 static void add_builtin_candidate
182 static void build_builtin_candidate
192 tsubst_flags_t);
195 tsubst_flags_t);
215 tsubst_flags_t);
219 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
220 NAME can take many forms... */
222 bool
224 {
225 /* Just accept something we've already complained about. */
234 {
240 else
242 }
243 else
244 {
245 /* In the case of:
247 template <class T> struct S { ~S(); };
248 int i;
249 i.~S();
251 NAME will be a class template. */
254 }
259 }
261 /* We want the address of a function or method. We avoid creating a
262 pointer-to-member function. */
264 tree
266 {
269 /* We have to do these by hand to avoid real pointer to member
270 functions. */
272 {
274 {
278 complain);
279 }
281 }
282 else
286 }
288 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
289 POINTER_TYPE to those. Note, pointer to member function types
290 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
291 two variants. build_call_a is the primitive taking an array of
292 arguments, while build_call_n is a wrapper that handles varargs. */
294 tree
296 {
299 else
300 {
310 }
311 }
313 /* Update various flags in cfun and the call itself based on what is being
314 called. Split out of build_call_a so that bot_manip can use it too. */
316 void
318 {
322 /* We check both the decl and the type; a function may be known not to
323 throw without being declared throw(). */
337 }
339 tree
341 {
342 tree decl;
343 tree result_type;
344 tree fntype;
354 /* An rvalue has no cv-qualifiers. */
365 {
366 /* We invoke build_call directly for several library
367 functions. These may have been declared normally if
368 we're building libgcc, so we can't just check
369 DECL_ARTIFICIAL. */
374 }
380 /* Don't pass empty class objects by value. This is useful
381 for tags in STL, which are used to control overload resolution.
382 We don't need to handle other cases of copying empty classes. */
385 {
389 {
393 }
394 }
397 }
399 /* New overloading code. */
406 };
408 /* Information for providing diagnostics about why overloading failed. */
411 rr_none,
412 rr_arity,
413 rr_explicit_conversion,
414 rr_template_conversion,
415 rr_arg_conversion,
416 rr_bad_arg_conversion,
417 rr_template_unification,
418 rr_invalid_copy,
419 rr_constraint_failure
420 };
423 /* The index of the argument, 0-based. */
425 /* The actual argument or its type. */
426 tree from;
427 /* The type of the parameter. */
428 tree to_type;
429 };
434 /* Information about an arity mismatch. */
436 /* The expected number of arguments. */
438 /* The actual number of arguments in the call. */
440 /* Whether the call was a varargs call. */
443 /* Information about an argument conversion mismatch. */
445 /* Same, but for bad argument conversions. */
447 /* Information about template unification failures. These are the
448 parameters passed to fn_type_unification. */
450 tree tmpl;
451 tree explicit_targs;
455 tree return_type;
456 unification_kind_t strict;
459 /* Information about template instantiation failures. These are the
460 parameters passed to instantiate_template. */
462 tree tmpl;
463 tree targs;
466 };
469 /* The FUNCTION_DECL that will be called if this candidate is
470 selected by overload resolution. */
471 tree fn;
472 /* If not NULL_TREE, the first argument to use when calling this
473 function. */
474 tree first_arg;
475 /* The rest of the arguments to use when calling this function. If
476 there are no further arguments this may be NULL or it may be an
477 empty vector. */
479 /* The implicit conversion sequences for each of the arguments to
480 FN. */
482 /* The number of implicit conversion sequences. */
484 /* If FN is a user-defined conversion, the standard conversion
485 sequence from the type returned by FN to the desired destination
486 type. */
489 /* If FN is a member function, the binfo indicating the path used to
490 qualify the name of FN at the call site. This path is used to
491 determine whether or not FN is accessible if it is selected by
492 overload resolution. The DECL_CONTEXT of FN will always be a
493 (possibly improper) base of this binfo. */
494 tree access_path;
495 /* If FN is a non-static member function, the binfo indicating the
496 subobject to which the `this' pointer should be converted if FN
497 is selected by overload resolution. The type pointed to by
498 the `this' pointer must correspond to the most derived class
499 indicated by the CONVERSION_PATH. */
500 tree conversion_path;
501 tree template_decl;
502 tree explicit_targs;
507 /* The flags active in add_candidate. */
509 };
511 /* Returns true iff T is a null pointer constant in the sense of
512 [conv.ptr]. */
514 bool
516 {
519 /* [conv.ptr]
521 A null pointer constant is an integral constant expression
522 (_expr.const_) rvalue of integer type that evaluates to zero or
523 an rvalue of type std::nullptr_t. */
528 {
529 /* Core issue 903 says only literal 0 is a null pointer constant. */
535 }
537 {
542 }
545 }
547 /* Returns true iff T is a null member pointer value (4.11). */
549 bool
551 {
560 else
562 }
564 /* Returns nonzero if PARMLIST consists of only default parms,
565 ellipsis, and/or undeduced parameter packs. */
567 bool
569 {
576 }
578 /* Allocate N bytes of memory from the conversion obstack. The memory
579 is zeroed before being returned. */
583 {
586 {
589 }
593 }
595 /* Allocate rejection reasons. */
599 {
604 }
608 {
614 }
618 {
625 }
629 {
636 }
640 {
646 }
650 {
656 }
663 {
670 /* Copy args to our own storage. */
678 }
682 {
684 }
688 {
691 }
693 // Build a constraint failure record, saving information into the
694 // template_instantiation field of the rejection. If FN is not a template
695 // declaration, the TMPL member is the FN declaration and TARGS is empty.
699 {
702 {
705 }
706 else
707 {
710 }
712 }
714 /* Dynamically allocate a conversion. */
718 {
723 }
725 /* Make sure that all memory on the conversion obstack has been
726 freed. */
728 void
730 {
734 }
736 /* Dynamically allocate an array of N conversions. */
740 {
742 }
746 {
750 /* Note that the caller is responsible for filling in t->cand for
751 user-defined conversions. */
757 {
773 }
779 }
781 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
782 specialization of std::initializer_list<T>, if such a conversion is
783 possible. */
787 {
793 tree val;
795 /* Within a list-initialization we can have more user-defined
796 conversions. */
798 /* But no narrowing conversions. */
801 /* Can't make an array of these types. */
808 {
809 conversion *sub
816 }
824 {
832 }
835 }
837 /* Return the next conversion of the conversion chain (if applicable),
838 or NULL otherwise. Please use this function instead of directly
839 accessing fields of struct conversion. */
843 {
850 }
852 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
853 is a valid aggregate initializer for array type ATYPE. */
855 static bool
857 {
861 {
867 else
869 complain);
872 }
874 }
876 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
877 aggregate class, if such a conversion is possible. */
881 {
887 /* We already called reshape_init in implicit_conversion. */
889 /* The conversions within the init-list aren't affected by the enclosing
890 context; they're always simple copy-initialization. */
894 {
896 tree val;
902 /* Value-initialization of reference is ill-formed. */
904 else
905 {
909 }
915 else
917 complain);
924 }
936 }
938 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
939 array type, if such a conversion is possible. */
943 {
948 tree val;
953 /* We might need to propagate the size from the element to the array. */
958 {
962 }
967 {
968 conversion *sub
980 }
989 }
991 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
992 complex type, if such a conversion is possible. */
996 tsubst_flags_t complain)
997 {
1002 tree val;
1013 {
1014 conversion *sub
1026 }
1035 }
1037 /* Build a representation of the identity conversion from EXPR to
1038 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1042 {
1050 }
1052 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1053 were multiple user-defined conversions to accomplish the job.
1054 Build a conversion that indicates that ambiguity. */
1058 {
1066 }
1068 tree
1070 {
1074 }
1076 /* Returns the standard conversion path (see [conv]) from type FROM to type
1077 TO, if any. For proper handling of null pointer constants, you must
1078 also pass the expression EXPR to convert from. If C_CAST_P is true,
1079 this conversion is coming from a C-style cast. */
1084 {
1088 tree qualified_to;
1092 {
1095 }
1101 {
1103 {
1109 }
1111 {
1112 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1115 }
1116 }
1123 {
1127 }
1129 {
1131 {
1132 tree bitfield_type;
1135 {
1138 }
1139 }
1143 }
1145 /* Allow conversion between `__complex__' data types. */
1147 {
1148 /* The standard conversion sequence to convert FROM to TO is
1149 the standard conversion sequence to perform componentwise
1150 conversion. */
1155 {
1158 }
1159 else
1163 }
1166 {
1170 }
1172 /* [conv.ptr]
1173 A null pointer constant can be converted to a pointer type; ... A
1174 null pointer constant of integral type can be converted to an
1175 rvalue of type std::nullptr_t. */
1183 {
1184 /* For backwards brain damage compatibility, allow interconversion of
1185 pointers and integers with a pedwarn. */
1188 }
1190 {
1191 /* For backwards brain damage compatibility, allow interconversion of
1192 enums and integers with a pedwarn. */
1195 }
1198 {
1199 tree to_pointee;
1200 tree from_pointee;
1205 ;
1209 {
1211 /* Don't try to apply restrict to void. */
1213 from = build_pointer_type
1216 }
1218 {
1223 && (same_type_ignoring_top_level_qualifiers_p
1226 {
1230 }
1233 }
1236 /* [conv.ptr]
1238 An rvalue of type "pointer to cv D," where D is a
1239 class type, can be converted to an rvalue of type
1240 "pointer to cv B," where B is a base class (clause
1241 _class.derived_) of D. If B is an inaccessible
1242 (clause _class.access_) or ambiguous
1243 (_class.member.lookup_) base class of D, a program
1244 that necessitates this conversion is ill-formed.
1245 Therefore, we use DERIVED_FROM_P, and do not check
1246 access or uniqueness. */
1248 {
1249 from =
1255 }
1257 {
1258 /* A prvalue of type "pointer to transaction_safe function" can be
1259 converted to a prvalue of type "pointer to function". */
1262 {
1265 }
1266 }
1269 {
1272 }
1273 else
1274 {
1277 }
1282 /* In a C-style cast, we ignore CV-qualification because we
1283 are allowed to perform a static_cast followed by a
1284 const_cast. */
1289 /* converting from string constant to char *. */
1291 /* Allow conversions among compatible ObjC pointer types (base
1292 conversions have been already handled above). */
1297 {
1300 }
1301 else
1305 }
1307 {
1319 tbase,
1325 }
1327 {
1328 /* [conv.bool]
1330 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1331 to member type can be converted to a prvalue of type bool. ...
1332 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1333 std::nullptr_t can be converted to a prvalue of type bool; */
1339 {
1350 }
1353 }
1354 /* We don't check for ENUMERAL_TYPE here because there are no standard
1355 conversions to enum type. */
1356 /* As an extension, allow conversion to complex type. */
1358 {
1365 /* Give this a better rank if it's a promotion. */
1369 }
1375 {
1379 /* The derived-to-base conversion indicates the initialization
1380 of a parameter with base type from an object of a derived
1381 type. A temporary object is created to hold the result of
1382 the conversion unless we're binding directly to a reference. */
1384 }
1385 else
1392 }
1394 /* Returns nonzero if T1 is reference-related to T2. */
1396 bool
1398 {
1405 /* [dcl.init.ref]
1407 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1408 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1409 of T2. */
1413 }
1415 /* Returns nonzero if T1 is reference-compatible with T2. */
1417 static bool
1419 {
1420 /* [dcl.init.ref]
1422 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1423 reference-related to T2 and cv1 is the same cv-qualification as,
1424 or greater cv-qualification than, cv2. */
1427 }
1429 /* A reference of the indicated TYPE is being bound directly to the
1430 expression represented by the implicit conversion sequence CONV.
1431 Return a conversion sequence for this binding. */
1435 {
1436 tree t;
1443 /* [over.ics.rank]
1445 When a parameter of reference type binds directly
1446 (_dcl.init.ref_) to an argument expression, the implicit
1447 conversion sequence is the identity conversion, unless the
1448 argument expression has a type that is a derived class of the
1449 parameter type, in which case the implicit conversion sequence is
1450 a derived-to-base Conversion.
1452 If the parameter binds directly to the result of applying a
1453 conversion function to the argument expression, the implicit
1454 conversion sequence is a user-defined conversion sequence
1455 (_over.ics.user_), with the second standard conversion sequence
1456 either an identity conversion or, if the conversion function
1457 returns an entity of a type that is a derived class of the
1458 parameter type, a derived-to-base conversion. */
1460 {
1461 /* Represent the derived-to-base conversion. */
1463 /* We will actually be binding to the base-class subobject in
1464 the derived class, so we mark this conversion appropriately.
1465 That way, convert_like knows not to generate a temporary. */
1467 }
1469 }
1471 /* Returns the conversion path from type FROM to reference type TO for
1472 purposes of reference binding. For lvalue binding, either pass a
1473 reference type to FROM or an lvalue expression to EXPR. If the
1474 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1475 the conversion returned. If C_CAST_P is true, this
1476 conversion is coming from a C-style cast. */
1480 tsubst_flags_t complain)
1481 {
1485 tree tfrom;
1488 cp_lvalue_kind gl_kind;
1492 {
1497 }
1500 {
1502 /* DR 1288: Otherwise, if the initializer list has a single element
1503 of type E and ... [T's] referenced type is reference-related to E,
1504 the object or reference is initialized from that element... */
1506 {
1512 {
1516 }
1517 }
1518 /* Otherwise, if T is a reference type, a prvalue temporary of the
1519 type referenced by T is copy-list-initialized or
1520 direct-list-initialized, depending on the kind of initialization
1521 for the reference, and the reference is bound to that temporary. */
1524 skip:;
1525 }
1528 {
1533 else
1535 }
1537 {
1540 /* A class prvalue is not a glvalue. */
1542 }
1543 else
1551 /* Figure out whether or not the types are reference-related and
1552 reference compatible. We have to do this after stripping
1553 references from FROM. */
1555 /* If this is a C cast, first convert to an appropriately qualified
1556 type, so that we can later do a const_cast to the desired type. */
1562 /* Directly bind reference when target expression's type is compatible with
1563 the reference and expression is an lvalue. In DR391, the wording in
1564 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1565 const and rvalue references to rvalues of compatible class type.
1566 We should also do direct bindings for non-class xvalues. */
1568 && (gl_kind
1572 {
1573 /* [dcl.init.ref]
1575 If the initializer expression
1577 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1578 is reference-compatible with "cv2 T2,"
1580 the reference is bound directly to the initializer expression
1581 lvalue.
1583 [...]
1584 If the initializer expression is an rvalue, with T2 a class type,
1585 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1586 is bound to the object represented by the rvalue or to a sub-object
1587 within that object. */
1593 /* The top-level caller requested that we pretend that the lvalue
1594 be treated as an rvalue. */
1597 /* Handle rvalue reference to function properly. */
1598 conv->rvaluedness_matches_p
1600 else
1601 conv->rvaluedness_matches_p
1606 /* For the purposes of overload resolution, we ignore the fact
1607 this expression is a bitfield or packed field. (In particular,
1608 [over.ics.ref] says specifically that a function with a
1609 non-const reference parameter is viable even if the
1610 argument is a bitfield.)
1612 However, when we actually call the function we must create
1613 a temporary to which to bind the reference. If the
1614 reference is volatile, or isn't const, then we cannot make
1615 a temporary, so we just issue an error when the conversion
1616 actually occurs. */
1619 /* Don't allow binding of lvalues (other than function lvalues) to
1620 rvalue references. */
1626 /* Nor the reverse. */
1637 }
1638 /* [class.conv.fct] A conversion function is never used to convert a
1639 (possibly cv-qualified) object to the (possibly cv-qualified) same
1640 object type (or a reference to it), to a (possibly cv-qualified) base
1641 class of that type (or a reference to it).... */
1644 {
1645 /* [dcl.init.ref]
1647 If the initializer expression
1649 -- has a class type (i.e., T2 is a class type) can be
1650 implicitly converted to an lvalue of type "cv3 T3," where
1651 "cv1 T1" is reference-compatible with "cv3 T3". (this
1652 conversion is selected by enumerating the applicable
1653 conversion functions (_over.match.ref_) and choosing the
1654 best one through overload resolution. (_over.match_).
1656 the reference is bound to the lvalue result of the conversion
1657 in the second case. */
1659 complain);
1662 }
1664 /* From this point on, we conceptually need temporaries, even if we
1665 elide them. Only the cases above are "direct bindings". */
1669 /* [over.ics.rank]
1671 When a parameter of reference type is not bound directly to an
1672 argument expression, the conversion sequence is the one required
1673 to convert the argument expression to the underlying type of the
1674 reference according to _over.best.ics_. Conceptually, this
1675 conversion sequence corresponds to copy-initializing a temporary
1676 of the underlying type with the argument expression. Any
1677 difference in top-level cv-qualification is subsumed by the
1678 initialization itself and does not constitute a conversion. */
1680 /* [dcl.init.ref]
1682 Otherwise, the reference shall be an lvalue reference to a
1683 non-volatile const type, or the reference shall be an rvalue
1684 reference.
1686 We try below to treat this as a bad conversion to improve diagnostics,
1687 but if TO is an incomplete class, we need to reject this conversion
1688 now to avoid unnecessary instantiation. */
1693 /* We're generating a temporary now, but don't bind any more in the
1694 conversion (specifically, don't slice the temporary returned by a
1695 conversion operator). */
1698 /* Core issue 899: When [copy-]initializing a temporary to be bound
1699 to the first parameter of a copy constructor (12.8) called with
1700 a single argument in the context of direct-initialization,
1701 explicit conversion functions are also considered.
1703 So don't set LOOKUP_ONLYCONVERTING in that case. */
1714 {
1715 /* If initializing the temporary used a conversion function,
1716 recalculate the second conversion sequence. */
1720 {
1723 conversion *new_second
1729 }
1730 }
1733 /* This reference binding, unlike those above, requires the
1734 creation of a temporary. */
1738 /* [dcl.init.ref]
1740 Otherwise, the reference shall be an lvalue reference to a
1741 non-volatile const type, or the reference shall be an rvalue
1742 reference. */
1746 /* [dcl.init.ref]
1748 Otherwise, a temporary of type "cv1 T1" is created and
1749 initialized from the initializer expression using the rules for a
1750 non-reference copy initialization. If T1 is reference-related to
1751 T2, cv1 must be the same cv-qualification as, or greater
1752 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1757 }
1759 /* Returns the implicit conversion sequence (see [over.ics]) from type
1760 FROM to type TO. The optional expression EXPR may affect the
1761 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1762 true, this conversion is coming from a C-style cast. */
1767 {
1774 /* Other flags only apply to the primary function in overload
1775 resolution, or after we've chosen one. */
1780 /* FIXME: actually we don't want warnings either, but we can't just
1781 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1782 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1783 We really ought not to issue that warning until we've committed
1784 to that conversion. */
1787 /* Call reshape_init early to remove redundant braces. */
1792 {
1797 }
1801 else
1808 {
1812 /* As an extension, allow list-initialization of _Complex. */
1814 {
1818 }
1820 /* Allow conversion from an initializer-list with one element to a
1821 scalar type. */
1823 {
1825 tree elt;
1831 else
1837 {
1840 /* Too many levels of braces, i.e. '{{1}}'. */
1843 }
1844 }
1847 }
1853 {
1865 /* We used to try to bind a reference to a temporary here, but that
1866 is now handled after the recursive call to this function at the end
1867 of reference_binding. */
1869 }
1872 }
1874 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1875 functions. ARGS will not be changed until a single candidate is
1876 selected. */
1885 {
1903 }
1905 /* Return the number of remaining arguments in the parameter list
1906 beginning with ARG. */
1908 static int
1910 {
1915 n++;
1918 }
1920 /* Create an overload candidate for the function or method FN called
1921 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1922 FLAGS is passed on to implicit_conversion.
1924 This does not change ARGS.
1926 CTYPE, if non-NULL, is the type we want to pretend this function
1927 comes from for purposes of overload resolution. */
1934 tsubst_flags_t complain)
1935 {
1939 tree parmnode;
1945 /* At this point we should not see any functions which haven't been
1946 explicitly declared, except for friend functions which will have
1947 been found using argument dependent lookup. */
1950 /* The `this', `in_chrg' and VTT arguments to constructors are not
1951 considered in overload resolution. */
1953 {
1957 {
1960 }
1961 }
1962 else
1968 /* 13.3.2 - Viable functions [over.match.viable]
1969 First, to be a viable function, a candidate function shall have enough
1970 parameters to agree in number with the arguments in the list.
1972 We need to check this first; otherwise, checking the ICSes might cause
1973 us to produce an ill-formed template instantiation. */
1977 {
1981 }
1985 {
1989 }
1991 /* Second, for a function to be viable, its constraints must be
1992 satisfied. */
1995 {
1998 }
2000 /* When looking for a function from a subobject from an implicit
2001 copy/move constructor/operator=, don't consider anything that takes (a
2002 reference to) an unrelated type. See c++/44909 and core 1092. */
2004 {
2010 else
2013 {
2016 ctype))
2018 }
2020 /* This only applies at the top level. */
2022 }
2027 /* Third, for F to be a viable function, there shall exist for each
2028 argument an implicit conversion sequence that converts that argument
2029 to the corresponding parameter of F. */
2034 {
2036 tree arg;
2045 else
2054 {
2060 /* The type of the implicit object parameter ('this') for
2061 overload resolution is not always the same as for the
2062 function itself; conversion functions are considered to
2063 be members of the class being converted, and functions
2064 introduced by a using-declaration are considered to be
2065 members of the class that uses them.
2067 Since build_over_call ignores the ICS for the `this'
2068 parameter, we can just change the parm type. */
2070 {
2071 parmtype = cp_build_qualified_type
2074 {
2075 /* If the function has a ref-qualifier, the implicit
2076 object parameter has reference type. */
2079 /* The special handling of 'this' conversions in compare_ics
2080 does not apply if there is a ref-qualifier. */
2082 }
2083 else
2084 {
2088 }
2089 }
2091 /* Core issue 899: When [copy-]initializing a temporary to be bound
2092 to the first parameter of a copy constructor (12.8) called with
2093 a single argument in the context of direct-initialization,
2094 explicit conversion functions are also considered.
2096 So set LOOKUP_COPY_PARM to let reference_binding know that
2097 it's being called in that context. We generalize the above
2098 to handle move constructors and template constructors as well;
2099 the standardese should soon be updated similarly. */
2103 && (same_type_ignoring_top_level_qualifiers_p
2105 {
2108 /* We allow user-defined conversions within init-lists, but
2109 don't list-initialize the copy parm, as that would mean
2110 using two levels of braces for the same type. */
2114 }
2115 else
2121 }
2122 else
2123 {
2127 }
2134 {
2138 }
2141 {
2144 }
2145 }
2147 out:
2150 }
2152 /* Create an overload candidate for the conversion function FN which will
2153 be invoked for expression OBJ, producing a pointer-to-function which
2154 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2155 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2156 passed on to implicit_conversion.
2158 Actually, we don't really care about FN; we care about the type it
2159 converts to. There may be multiple conversion functions that will
2160 convert to that type, and we rely on build_user_type_conversion_1 to
2161 choose the best one; so when we create our candidate, we record the type
2162 instead of the function. */
2168 tsubst_flags_t complain)
2169 {
2187 /* Don't bother looking up the same type twice. */
2192 {
2198 else
2203 {
2207 }
2211 {
2215 }
2216 else
2217 {
2221 }
2228 {
2231 }
2238 }
2242 {
2246 }
2250 }
2252 static void
2256 {
2270 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2271 conversion ops are allowed. We handle that here by just checking for
2272 boolean_type_node because other operators don't ask for it. COND_EXPR
2273 also does contextual conversion to bool for the first operand, but we
2274 handle that in build_conditional_expr, and type1 here is operand 2. */
2279 {
2286 {
2288 /* We need something for printing the candidate. */
2292 }
2294 {
2298 }
2300 }
2302 /* For COND_EXPR we rearranged the arguments; undo that now. */
2304 {
2309 complain);
2312 else
2313 {
2316 boolean_type_node);
2317 }
2318 }
2325 }
2327 static bool
2329 {
2331 }
2333 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2335 static bool
2337 {
2338 /* [over.built]
2340 In this section, the term promoted integral type is used to refer
2341 to those integral types which are preserved by integral promotion
2342 (including e.g. int and long but excluding e.g. char).
2343 Similarly, the term promoted arithmetic type refers to promoted
2344 integral types plus floating types. */
2348 }
2350 /* Create any builtin operator overload candidates for the operator in
2351 question given the converted operand types TYPE1 and TYPE2. The other
2352 args are passed through from add_builtin_candidates to
2353 build_builtin_candidate.
2355 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2356 If CODE is requires candidates operands of the same type of the kind
2357 of which TYPE1 and TYPE2 are, we add both candidates
2358 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2360 static void
2364 tsubst_flags_t complain)
2365 {
2367 {
2375 }
2378 {
2380 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2381 and VQ is either volatile or empty, there exist candidate operator
2382 functions of the form
2383 VQ T& operator++(VQ T&);
2384 T operator++(VQ T&, int);
2385 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2386 type other than bool, and VQ is either volatile or empty, there exist
2387 candidate operator functions of the form
2388 VQ T& operator--(VQ T&);
2389 T operator--(VQ T&, int);
2390 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2391 complete object type, and VQ is either volatile or empty, there exist
2392 candidate operator functions of the form
2393 T*VQ& operator++(T*VQ&);
2394 T*VQ& operator--(T*VQ&);
2395 T* operator++(T*VQ&, int);
2396 T* operator--(T*VQ&, int); */
2405 {
2408 }
2411 /* 7 For every cv-qualified or cv-unqualified object type T, there
2412 exist candidate operator functions of the form
2414 T& operator*(T*);
2416 8 For every function type T, there exist candidate operator functions of
2417 the form
2418 T& operator*(T*); */
2427 /* 9 For every type T, there exist candidate operator functions of the form
2428 T* operator+(T*);
2430 10For every promoted arithmetic type T, there exist candidate operator
2431 functions of the form
2432 T operator+(T);
2433 T operator-(T); */
2443 /* 11For every promoted integral type T, there exist candidate operator
2444 functions of the form
2445 T operator~(T); */
2452 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2453 is the same type as C2 or is a derived class of C2, T is a complete
2454 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2455 there exist candidate operator functions of the form
2456 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2457 where CV12 is the union of CV1 and CV2. */
2461 {
2469 }
2472 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2473 didate operator functions of the form
2474 LR operator*(L, R);
2475 LR operator/(L, R);
2476 LR operator+(L, R);
2477 LR operator-(L, R);
2478 bool operator<(L, R);
2479 bool operator>(L, R);
2480 bool operator<=(L, R);
2481 bool operator>=(L, R);
2482 bool operator==(L, R);
2483 bool operator!=(L, R);
2484 where LR is the result of the usual arithmetic conversions between
2485 types L and R.
2487 14For every pair of types T and I, where T is a cv-qualified or cv-
2488 unqualified complete object type and I is a promoted integral type,
2489 there exist candidate operator functions of the form
2490 T* operator+(T*, I);
2491 T& operator[](T*, I);
2492 T* operator-(T*, I);
2493 T* operator+(I, T*);
2494 T& operator[](I, T*);
2496 15For every T, where T is a pointer to complete object type, there exist
2497 candidate operator functions of the form112)
2498 ptrdiff_t operator-(T, T);
2500 16For every pointer or enumeration type T, there exist candidate operator
2501 functions of the form
2502 bool operator<(T, T);
2503 bool operator>(T, T);
2504 bool operator<=(T, T);
2505 bool operator>=(T, T);
2506 bool operator==(T, T);
2507 bool operator!=(T, T);
2509 17For every pointer to member type T, there exist candidate operator
2510 functions of the form
2511 bool operator==(T, T);
2512 bool operator!=(T, T); */
2519 {
2522 }
2535 {
2538 }
2540 {
2543 }
2544 /* Fall through. */
2560 {
2563 }
2566 {
2569 }
2577 {
2580 }
2582 {
2585 }
2588 /* 18For every pair of promoted integral types L and R, there exist candi-
2589 date operator functions of the form
2590 LR operator%(L, R);
2591 LR operator&(L, R);
2592 LR operator^(L, R);
2593 LR operator|(L, R);
2594 L operator<<(L, R);
2595 L operator>>(L, R);
2596 where LR is the result of the usual arithmetic conversions between
2597 types L and R. */
2605 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2609 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2610 type, VQ is either volatile or empty, and R is a promoted arithmetic
2611 type, there exist candidate operator functions of the form
2612 VQ L& operator=(VQ L&, R);
2613 VQ L& operator*=(VQ L&, R);
2614 VQ L& operator/=(VQ L&, R);
2615 VQ L& operator+=(VQ L&, R);
2616 VQ L& operator-=(VQ L&, R);
2618 20For every pair T, VQ), where T is any type and VQ is either volatile
2619 or empty, there exist candidate operator functions of the form
2620 T*VQ& operator=(T*VQ&, T*);
2622 21For every pair T, VQ), where T is a pointer to member type and VQ is
2623 either volatile or empty, there exist candidate operator functions of
2624 the form
2625 VQ T& operator=(VQ T&, T);
2627 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2628 unqualified complete object type, VQ is either volatile or empty, and
2629 I is a promoted integral type, there exist candidate operator func-
2630 tions of the form
2631 T*VQ& operator+=(T*VQ&, I);
2632 T*VQ& operator-=(T*VQ&, I);
2634 23For every triple L, VQ, R), where L is an integral or enumeration
2635 type, VQ is either volatile or empty, and R is a promoted integral
2636 type, there exist candidate operator functions of the form
2638 VQ L& operator%=(VQ L&, R);
2639 VQ L& operator<<=(VQ L&, R);
2640 VQ L& operator>>=(VQ L&, R);
2641 VQ L& operator&=(VQ L&, R);
2642 VQ L& operator^=(VQ L&, R);
2643 VQ L& operator|=(VQ L&, R); */
2647 {
2651 {
2654 }
2667 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2680 {
2683 }
2688 }
2693 /* [over.built]
2695 For every pair of promoted arithmetic types L and R, there
2696 exist candidate operator functions of the form
2698 LR operator?(bool, L, R);
2700 where LR is the result of the usual arithmetic conversions
2701 between types L and R.
2703 For every type T, where T is a pointer or pointer-to-member
2704 type, there exist candidate operator functions of the form T
2705 operator?(bool, T, T); */
2709 /* That's OK. */
2712 /* Otherwise, the types should be pointers. */
2716 /* We don't check that the two types are the same; the logic
2717 below will actually create two candidates; one in which both
2718 parameter types are TYPE1, and one in which both parameter
2719 types are TYPE2. */
2730 }
2732 /* Make sure we don't create builtin candidates with dependent types. */
2736 {
2737 /* Try to recover if one of the types is non-dependent. But if
2738 there's only one type, there's nothing we can do. */
2741 /* And we lose if both are dependent. */
2744 /* Or if they have different forms. */
2752 }
2754 /* If we're dealing with two pointer types or two enumeral types,
2755 we need candidates for both of them. */
2764 {
2766 {
2768 error_mark_node,
2769 error_mark_node,
2770 CPO_CONVERSION,
2771 tf_none);
2773 {
2774 build_builtin_candidate
2778 }
2779 }
2781 build_builtin_candidate
2783 build_builtin_candidate
2786 }
2788 build_builtin_candidate
2790 }
2792 tree
2794 {
2800 }
2802 /* There are three conditions of builtin candidates:
2804 1) bool-taking candidates. These are the same regardless of the input.
2805 2) pointer-pair taking candidates. These are generated for each type
2806 one of the input types converts to.
2807 3) arithmetic candidates. According to the standard, we should generate
2808 all of these, but I'm trying not to...
2810 Here we generate a superset of the possible candidates for this particular
2811 case. That is a subset of the full set the standard defines, plus some
2812 other cases which the standard disallows. add_builtin_candidate will
2813 filter out the invalid set. */
2815 static void
2819 {
2823 /* TYPES[i] is the set of possible builtin-operator parameter types
2824 we will consider for the Ith argument. */
2829 {
2832 else
2834 }
2837 {
2838 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2839 and VQ is either volatile or empty, there exist candidate operator
2840 functions of the form
2841 VQ T& operator++(VQ T&); */
2851 /* 24There also exist candidate operator functions of the form
2852 bool operator!(bool);
2853 bool operator&&(bool, bool);
2854 bool operator||(bool, bool); */
2857 build_builtin_candidate
2864 build_builtin_candidate
2882 /* Fall through. */
2886 }
2892 {
2894 ;
2896 {
2897 tree convs;
2905 {
2910 }
2916 {
2929 {
2935 }
2939 }
2940 }
2941 else
2942 {
2947 {
2953 }
2955 }
2956 }
2958 /* Run through the possible parameter types of both arguments,
2959 creating candidates with those parameter types. */
2961 {
2963 tree u;
2967 add_builtin_candidate
2970 else
2971 add_builtin_candidate
2974 }
2978 }
2981 /* If TMPL can be successfully instantiated as indicated by
2982 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2984 TMPL is the template. EXPLICIT_TARGS are any explicit template
2985 arguments. ARGLIST is the arguments provided at the call-site.
2986 This does not change ARGLIST. The RETURN_TYPE is the desired type
2987 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2988 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2989 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2997 tsubst_flags_t complain)
2998 {
3008 tree arg;
3010 tree fn;
3014 /* We don't do deduction on the in-charge parameter, the VTT
3015 parameter or 'this'. */
3017 {
3021 /* We're deducing for a call to the result of a template conversion
3023 else
3025 }
3030 {
3033 else
3035 }
3045 {
3048 }
3052 {
3055 }
3060 args_without_in_chrg,
3061 nargs_without_in_chrg,
3066 {
3067 /* Don't repeat unification later if it already resulted in errors. */
3071 nargs_without_in_chrg,
3073 else
3076 }
3078 /* In [class.copy]:
3080 A member function template is never instantiated to perform the
3081 copy of a class object to an object of its class type.
3083 It's a little unclear what this means; the standard explicitly
3084 does allow a template to be used to copy a class. For example,
3085 in:
3087 struct A {
3088 A(A&);
3089 template <class T> A(const T&);
3090 };
3091 const A f ();
3092 void g () { A a (f ()); }
3094 the member template will be used to make the copy. The section
3095 quoted above appears in the paragraph that forbids constructors
3096 whose only parameter is (a possibly cv-qualified variant of) the
3097 class type, and a logical interpretation is that the intent was
3098 to forbid the instantiation of member templates which would then
3099 have that form. */
3101 {
3104 ctype))
3105 {
3108 }
3109 }
3112 /* Aha, this is a conversion function. */
3115 else
3120 /* This situation can occur if a member template of a template
3121 class is specialized. Then, instantiate_template might return
3122 an instantiation of the specialization, in which case the
3123 DECL_TI_TEMPLATE field will point at the original
3124 specialization. For example:
3126 template <class T> struct S { template <class U> void f(U);
3127 template <> void f(int) {}; };
3128 S<double> sd;
3129 sd.f(3);
3131 Here, TMPL will be template <class U> S<double>::f(U).
3132 And, instantiate template will give us the specialization
3133 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3134 for this will point at template <class T> template <> S<T>::f(int),
3135 so that we can find the definition. For the purposes of
3136 overload resolution, however, we want the original TMPL. */
3138 else
3143 fail:
3146 }
3155 {
3156 return
3161 }
3163 /* Create an overload candidate for the conversion function template TMPL,
3164 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3165 pointer-to-function which will in turn be called with the argument list
3166 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3167 passed on to implicit_conversion. */
3171 tree obj,
3175 {
3176 return
3180 complain);
3181 }
3183 /* The CANDS are the set of candidates that were considered for
3184 overload resolution. Return the set of viable candidates, or CANDS
3185 if none are viable. If any of the candidates were viable, set
3186 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3187 considered viable only if it is strictly viable. */
3193 {
3199 /* Be strict inside templates, since build_over_call won't actually
3200 do the conversions to get pedwarns. */
3210 {
3214 {
3215 /* Be strict in the presence of a viable candidate. Also if
3216 there are template candidates, so that we get deduction errors
3217 for them instead of silently preferring a bad conversion. */
3220 {
3221 /* Put any spliced near matches back onto the main list so
3222 that we see them if there is no strict match. */
3228 }
3229 }
3232 {
3240 }
3241 else
3243 }
3246 }
3248 static bool
3250 {
3255 }
3257 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3258 words, it is about to become the "this" pointer for a member
3259 function call. Take the address of the object. */
3261 static tree
3263 {
3264 /* In a template, we are only concerned about the type of the
3265 expression, so we can take a shortcut. */
3270 }
3272 /* Returns true iff functions are equivalent. Equivalent functions are
3273 not '==' only if one is a function-local extern function or if
3274 both are extern "C". */
3278 {
3287 }
3289 /* Print information about a candidate being rejected due to INFO. */
3291 static void
3293 {
3298 {
3299 /* Conversion of implicit `this' argument failed. */
3301 /* A bad conversion for 'this' must be discarding cv-quals. */
3304 from);
3305 else
3309 }
3311 {
3316 tf_warning_or_error);
3317 }
3319 /* Conversion of conversion function return value failed. */
3322 else
3325 }
3327 /* Print information about a candidate with WANT parameters and we found
3328 HAVE. */
3330 static void
3332 {
3337 }
3339 /* Print information about one overload candidate CANDIDATE. MSGSTR
3340 is the text to print before the candidate itself.
3342 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3343 to have been run through gettext by the caller. This wart makes
3344 life simpler in print_z_candidates and for the translators. */
3346 static void
3349 {
3356 {
3367 else
3370 }
3377 else
3379 /* Give the user some information about why this candidate failed. */
3381 {
3385 {
3398 "cannot be converted to %qT with a qualification "
3404 "conversion function specialization to %qT is not an "
3409 /* We use template_unification_error_rejection if unification caused
3410 actual non-SFINAE errors, in which case we don't need to repeat
3411 them here. */
3413 {
3417 }
3418 /* Re-run template unification with diagnostics. */
3422 (make_tree_vec
3433 " a constructor taking a single argument of its own "
3437 {
3441 }
3445 /* This candidate didn't have any issues or we failed to
3446 handle a particular code. Either way... */
3448 }
3449 }
3450 }
3452 static void
3454 {
3461 /* Remove non-viable deleted candidates. */
3464 {
3469 else
3471 }
3472 /* ...if there are any non-deleted ones. */
3476 /* There may be duplicates in the set of candidates. We put off
3477 checking this condition as long as possible, since we have no way
3478 to eliminate duplicates from a set of functions in less than n^2
3479 time. Now we are about to emit an error message, so it is more
3480 permissible to go slowly. */
3482 {
3484 /* Skip builtin candidates and conversion functions. */
3489 {
3493 else
3495 }
3496 }
3500 }
3502 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3503 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3504 the result of the conversion function to convert it to the final
3505 desired type. Merge the two sequences into a single sequence,
3506 and return the merged sequence. */
3510 {
3516 /* Find the end of the second conversion sequence. */
3518 {
3519 /* The entire sequence is a user-conversion sequence. */
3523 }
3525 /* Replace the identity conversion with the user conversion
3526 sequence. */
3530 }
3532 /* Handle overload resolution for initializing an object of class type from
3533 an initializer list. First we look for a suitable constructor that
3534 takes a std::initializer_list; if we don't find one, we then look for a
3535 non-list constructor.
3537 Parameters are as for add_candidates, except that the arguments are in
3538 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3539 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3541 static void
3548 tsubst_flags_t complain)
3549 {
3554 /* We're looking for a ctor for list-initialization. */
3556 /* And we don't allow narrowing conversions. We also use this flag to
3557 avoid the copy constructor call for copy-list-initialization. */
3560 /* Always use the default constructor if the list is empty (DR 990). */
3563 ;
3564 /* If the class has a list ctor, try passing the list as a single
3565 argument first, but only consider list ctors. */
3567 {
3575 }
3579 /* We aren't looking for list-ctors anymore. */
3581 /* We allow more user-defined conversions within an init-list. */
3587 }
3589 /* Returns the best overload candidate to perform the requested
3590 conversion. This function is used for three the overloading situations
3591 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3592 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3593 per [dcl.init.ref], so we ignore temporary bindings. */
3597 tsubst_flags_t complain)
3598 {
3600 tree fromtype;
3614 /* We represent conversion within a hierarchy using RVALUE_CONV and
3615 BASE_CONV, as specified by [over.best.ics]; these become plain
3616 constructor calls, as specified in [dcl.init]. */
3621 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3622 creating a garbage BASELINK; constructors can't be inherited. */
3626 {
3631 {
3632 /* [class.conv.fct] A conversion function is never used to
3633 convert a (possibly cv-qualified) object to the (possibly
3634 cv-qualified) same object type (or a reference to it), to a
3635 (possibly cv-qualified) base class of that type (or a
3636 reference to it)... */
3637 }
3638 else
3640 }
3647 /* It's OK to bind a temporary for converting constructor arguments, but
3648 not in converting the return value of a conversion operator. */
3654 {
3659 /* We should never try to call the abstract or base constructor
3660 from here. */
3665 {
3666 /* List-initialization. */
3670 }
3671 else
3672 {
3677 }
3680 {
3683 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3684 set, then this is copy-initialization. In that case, "The
3685 result of the call is then used to direct-initialize the
3686 object that is the destination of the copy-initialization."
3687 [dcl.init]
3689 We represent this in the conversion sequence with an
3690 rvalue conversion, which means a constructor call. */
3693 cand->second_conv
3695 }
3696 }
3702 {
3706 /* If we are called to convert to a reference type, we are trying to
3707 find a direct binding, so don't even consider temporaries. If
3708 we don't find a direct binding, the caller will try again to
3709 look for a temporary binding. */
3720 {
3722 conversion *ics
3724 rettype,
3727 complain);
3729 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3730 copy-initialization. In that case, "The result of the
3731 call is then used to direct-initialize the object that is
3732 the destination of the copy-initialization." [dcl.init]
3734 We represent this in the conversion sequence with an
3735 rvalue conversion, which means a constructor call. But
3736 don't add a second rvalue conversion if there's already
3737 one there. Which there really shouldn't be, but it's
3738 harmless since we'd add it here anyway. */
3746 {
3750 }
3753 {
3754 /* 13.3.1.5: For direct-initialization, those explicit
3755 conversion functions that are not hidden within S and
3756 yield type T or a type that can be converted to type T
3757 with a qualification conversion (4.4) are also candidate
3758 functions. */
3759 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3760 I've raised this issue with the committee. --jason 9/2011 */
3763 }
3765 {
3767 cand->reason
3770 }
3773 {
3774 /* 13.3.3.1.2: If the user-defined conversion is specified by
3775 a specialization of a conversion function template, the
3776 second standard conversion sequence shall have exact match
3777 rank. */
3780 }
3781 }
3782 }
3786 {
3790 }
3794 {
3796 {
3800 }
3807 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3808 ambiguous conversion is no worse than another user-defined
3809 conversion. */
3812 }
3814 tree convtype;
3818 /* DR 5: [in the first step of copy-initialization]...if the function
3819 is a constructor, the call initializes a temporary of the
3820 cv-unqualified version of the destination type. */
3822 else
3824 /* Build the user conversion sequence. */
3825 conv = build_conv
3827 convtype,
3833 /* Remember that this was a list-initialization. */
3837 /* Combine it with the second conversion sequence. */
3842 }
3844 /* Wrapper for above. */
3846 tree
3848 tsubst_flags_t complain)
3849 {
3851 tree ret;
3857 {
3860 else
3861 {
3864 }
3865 }
3866 else
3871 }
3873 /* Subroutine of convert_nontype_argument.
3875 EXPR is an argument for a template non-type parameter of integral or
3876 enumeration type. Do any necessary conversions (that are permitted for
3877 non-type arguments) to convert it to the parameter type.
3879 If conversion is successful, returns the converted expression;
3880 otherwise, returns error_mark_node. */
3882 tree
3884 {
3887 tree t;
3895 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3902 /* for a non-type template-parameter of integral or
3903 enumeration type, integral promotions (4.5) and integral
3904 conversions (4.7) are applied. */
3905 /* It should be sufficient to check the outermost conversion step, since
3906 there are no qualification conversions to integer type. */
3909 {
3910 /* A conversion function is OK. If it isn't constexpr, we'll
3911 complain later that the argument isn't constant. */
3913 /* The lvalue-to-rvalue conversion is OK. */
3926 /* and fall through. */
3931 }
3935 else
3938 /* Free all the conversions we allocated. */
3942 }
3944 /* Do any initial processing on the arguments to a function call. */
3948 {
3950 tree arg;
3953 {
3957 {
3961 }
3964 }
3966 }
3968 /* Perform overload resolution on FN, which is called with the ARGS.
3970 Return the candidate function selected by overload resolution, or
3971 NULL if the event that overload resolution failed. In the case
3972 that overload resolution fails, *CANDIDATES will be the set of
3973 candidates considered, and ANY_VIABLE_P will be set to true or
3974 false to indicate whether or not any of the candidates were
3975 viable.
3977 The ARGS should already have gone through RESOLVE_ARGS before this
3978 function is called. */
3985 {
3987 tree explicit_targs;
3998 /* Check FN. */
4005 {
4009 }
4011 /* Add the various candidate functions. */
4016 LOOKUP_NORMAL,
4022 else
4027 }
4029 /* Print an error message about being unable to build a call to FN with
4030 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4031 be located; CANDIDATES is a possibly empty list of such
4032 functions. */
4034 static void
4037 {
4044 else
4049 }
4051 /* Return an expression for a call to FN (a namespace-scope function,
4052 or a static member function) with the ARGS. This may change
4053 ARGS. */
4055 tree
4057 tsubst_flags_t complain)
4058 {
4062 tree result;
4065 {
4069 }
4074 /* If this function was found without using argument dependent
4075 lookup, then we want to ignore any undeclared friend
4076 functions. */
4078 {
4083 {
4087 }
4088 }
4090 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4094 complain);
4097 {
4099 {
4100 // If there is a single (non-viable) function candidate,
4101 // let the error be diagnosed by cp_build_function_call_vec.
4106 // Otherwise, emit notes for non-viable candidates.
4110 }
4112 }
4113 else
4114 {
4116 /* If fn is template_id_expr, the call has explicit template arguments
4117 (e.g. func<int>(5)), communicate this info to build_over_call
4118 through flags so that later we can use it to decide whether to warn
4119 about peculiar null pointer conversion. */
4121 {
4122 /* If overload resolution selects a specialization of a
4123 function concept for non-dependent template arguments,
4124 the expression is true if the constraints are satisfied
4125 and false otherwise.
4127 NOTE: This is an extension of Concepts Lite TS that
4128 allows constraints to be used in expressions. */
4130 {
4136 }
4139 }
4142 }
4144 /* Free all the conversions we allocated. */
4148 }
4150 /* Build a call to a global operator new. FNNAME is the name of the
4151 operator (either "operator new" or "operator new[]") and ARGS are
4152 the arguments provided. This may change ARGS. *SIZE points to the
4153 total number of bytes required by the allocation, and is updated if
4154 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4155 be used. If this function determines that no cookie should be
4156 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4157 is not NULL_TREE, it is evaluated before calculating the final
4158 array size, and if it fails, the array size is replaced with
4159 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4160 is non-NULL, it will be set, upon return, to the allocation
4161 function called. */
4163 tree
4167 {
4169 tree fns;
4176 /* Set to (size_t)-1 if the size check fails. */
4178 {
4184 }
4190 /* Based on:
4192 [expr.new]
4194 If this lookup fails to find the name, or if the allocated type
4195 is not a class type, the allocation function's name is looked
4196 up in the global scope.
4198 we disregard block-scope declarations of "operator new". */
4201 /* Figure out what function is being called. */
4203 complain);
4205 /* If no suitable function could be found, issue an error message
4206 and give up. */
4208 {
4212 }
4214 /* If a cookie is required, add some extra space. Whether
4215 or not a cookie is required cannot be determined until
4216 after we know which function was called. */
4218 {
4220 tree arg_types;
4223 /* Skip the size_t parameter. */
4225 /* Check the remaining parameters (if any). */
4229 ptr_type_node))
4231 /* If we need a cookie, adjust the number of bytes allocated. */
4233 {
4234 /* Update the total size. */
4237 {
4238 /* Set to (size_t)-1 if the size check fails. */
4242 }
4243 /* Update the argument list to reflect the adjusted size. */
4245 }
4246 else
4248 }
4250 /* Tell our caller which function we decided to call. */
4254 /* Build the CALL_EXPR. */
4256 }
4258 /* Build a new call to operator(). This may change ARGS. */
4260 static tree
4262 {
4276 {
4278 /* It's no good looking for an overloaded operator() on a
4279 pointer-to-member-function. */
4280 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4282 }
4285 {
4289 }
4290 else
4294 {
4298 }
4300 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4304 {
4312 }
4317 {
4326 {
4333 add_template_conv_candidate
4337 else
4341 }
4342 }
4344 /* Be strict here because if we choose a bad conversion candidate, the
4345 errors we get won't mention the call context. */
4348 {
4350 {
4354 }
4356 }
4357 else
4358 {
4361 {
4363 {
4367 }
4369 }
4370 /* Since cand->fn will be a type, not a function, for a conversion
4371 function, we must be careful not to unconditionally look at
4372 DECL_NAME here. */
4376 else
4377 {
4379 complain);
4382 }
4383 }
4385 /* Free all the conversions we allocated. */
4389 }
4391 /* Wrapper for above. */
4393 tree
4395 {
4396 tree ret;
4401 }
4403 /* Called by op_error to prepare format strings suitable for the error
4404 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4405 and a suffix (controlled by NTYPES). */
4409 {
4419 else
4423 }
4425 static void
4428 {
4433 else
4437 {
4443 else
4455 else
4465 else
4476 else
4486 else
4491 else
4495 else
4500 }
4501 }
4503 /* Return the implicit conversion sequence that could be used to
4504 convert E1 to E2 in [expr.cond]. */
4508 {
4514 /* [expr.cond]
4516 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4517 implicitly converted (clause _conv_) to the type "lvalue reference to
4518 T2", subject to the constraint that in the conversion the
4519 reference must bind directly (_dcl.init.ref_) to an lvalue.
4521 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4522 implicitly converted to the type "rvalue reference to T2", subject to
4523 the constraint that the reference must bind directly. */
4525 {
4528 t1,
4529 e1,
4531 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4533 complain);
4536 }
4538 /* If E2 is a prvalue or if neither of the conversions above can be done
4539 and at least one of the operands has (possibly cv-qualified) class
4540 type: */
4544 /* [expr.cond]
4546 If E1 and E2 have class type, and the underlying class types are
4547 the same or one is a base class of the other: E1 can be converted
4548 to match E2 if the class of T2 is the same type as, or a base
4549 class of, the class of T1, and the cv-qualification of T2 is the
4550 same cv-qualification as, or a greater cv-qualification than, the
4551 cv-qualification of T1. If the conversion is applied, E1 is
4552 changed to an rvalue of type T2 that still refers to the original
4553 source class object (or the appropriate subobject thereof). */
4556 {
4558 {
4563 else
4566 }
4567 else
4569 }
4570 else
4571 /* [expr.cond]
4573 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4574 converted to the type that expression E2 would have if E2 were
4575 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4578 }
4580 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4581 arguments to the conditional expression. */
4583 static tree
4585 tsubst_flags_t complain)
4586 {
4587 tree arg2_type;
4588 tree arg3_type;
4597 /* As a G++ extension, the second argument to the conditional can be
4598 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4599 c'.) If the second operand is omitted, make sure it is
4600 calculated only once. */
4602 {
4607 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4610 else
4612 }
4614 /* If something has already gone wrong, just pass that fact up the
4615 tree. */
4625 {
4626 /* If arg1 is another cond_expr choosing between -1 and 0,
4627 then we can use its comparison. It may help to avoid
4628 additional comparison, produce more accurate diagnostics
4629 and enables folding. */
4639 /* force_rvalue can return error_mark on valid arguments. */
4651 {
4652 /* Rely on the error messages of the scalar version. */
4661 {
4669 }
4673 /* We could pass complain & tf_warning to unsafe_conversion_p,
4674 but the warnings (like Wsign-conversion) have already been
4675 given by the scalar build_conditional_expr_1. We still check
4676 unsafe_conversion_p to forbid truncating long long -> float. */
4678 {
4683 }
4685 {
4690 }
4700 }
4703 {
4709 {
4713 {
4719 }
4721 {
4727 }
4730 }
4731 }
4737 {
4740 "incompatible vector types in conditional expression: "
4744 }
4747 {
4750 }
4752 }
4754 /* [expr.cond]
4756 The first expression is implicitly converted to bool (clause
4757 _conv_). */
4759 LOOKUP_NORMAL);
4763 /* [expr.cond]
4765 If either the second or the third operand has type (possibly
4766 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4767 array-to-pointer (_conv.array_), and function-to-pointer
4768 (_conv.func_) standard conversions are performed on the second
4769 and third operands. */
4773 {
4774 /* Do the conversions. We don't these for `void' type arguments
4775 since it can't have any effect and since decay_conversion
4776 does not handle that case gracefully. */
4784 /* [expr.cond]
4786 One of the following shall hold:
4788 --The second or the third operand (but not both) is a
4789 throw-expression (_except.throw_); the result is of the
4790 type of the other and is an rvalue.
4792 --Both the second and the third operands have type void; the
4793 result is of type void and is an rvalue.
4795 We must avoid calling force_rvalue for expressions of type
4796 "void" because it will complain that their value is being
4797 used. */
4800 {
4802 {
4806 }
4809 }
4812 {
4814 {
4818 }
4821 }
4824 else
4825 {
4827 {
4830 "second operand to the conditional operator "
4831 "is of type %<void%>, but the third operand is "
4833 else
4835 "third operand to the conditional operator "
4836 "is of type %<void%>, but the second operand is "
4838 }
4840 }
4844 }
4845 /* [expr.cond]
4847 Otherwise, if the second and third operand have different types,
4848 and either has (possibly cv-qualified) class type, or if both are
4849 glvalues of the same value category and the same type except for
4850 cv-qualification, an attempt is made to convert each of those operands
4851 to the type of the other. */
4855 arg3_type)
4859 {
4864 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4870 /* [expr.cond]
4872 If both can be converted, or one can be converted but the
4873 conversion is ambiguous, the program is ill-formed. If
4874 neither can be converted, the operands are left unchanged and
4875 further checking is performed as described below. If exactly
4876 one conversion is possible, that conversion is applied to the
4877 chosen operand and the converted operand is used in place of
4878 the original operand for the remainder of this section. */
4883 {
4885 {
4892 else
4894 }
4896 }
4898 {
4902 /* Even if CONV2 is a valid conversion, the result of the
4903 conversion may be invalid. For example, if ARG3 has type
4904 "volatile X", and X does not have a copy constructor
4905 accepting a "volatile X&", then even if ARG2 can be
4906 converted to X, the conversion will fail. */
4910 }
4912 {
4919 }
4921 /* Free all the conversions we allocated. */
4927 /* If, after the conversion, both operands have class type,
4928 treat the cv-qualification of both operands as if it were the
4929 union of the cv-qualification of the operands.
4931 The standard is not clear about what to do in this
4932 circumstance. For example, if the first operand has type
4933 "const X" and the second operand has a user-defined
4934 conversion to "volatile X", what is the type of the second
4935 operand after this step? Making it be "const X" (matching
4936 the first operand) seems wrong, as that discards the
4937 qualification without actually performing a copy. Leaving it
4938 as "volatile X" seems wrong as that will result in the
4939 conditional expression failing altogether, even though,
4940 according to this step, the one operand could be converted to
4941 the type of the other. */
4949 }
4951 /* [expr.cond]
4953 If the second and third operands are glvalues of the same value
4954 category and have the same type, the result is of that type and
4955 value category. */
4959 {
4964 }
4966 /* [expr.cond]
4968 Otherwise, the result is an rvalue. If the second and third
4969 operand do not have the same type, and either has (possibly
4970 cv-qualified) class type, overload resolution is used to
4971 determine the conversions (if any) to be applied to the operands
4972 (_over.match.oper_, _over.built_). */
4976 {
4981 /* Rearrange the arguments so that add_builtin_candidate only has
4982 to know about two args. In build_builtin_candidate, the
4983 arguments are unscrambled. */
4988 COND_EXPR,
4989 NOP_EXPR,
4991 args,
4994 /* [expr.cond]
4996 If the overload resolution fails, the program is
4997 ill-formed. */
5000 {
5005 }
5008 {
5010 {
5013 }
5015 }
5017 /* [expr.cond]
5019 Otherwise, the conversions thus determined are applied, and
5020 the converted operands are used in place of the original
5021 operands for the remainder of this section. */
5030 }
5032 /* [expr.cond]
5034 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5035 and function-to-pointer (_conv.func_) standard conversions are
5036 performed on the second and third operands.
5038 We need to force the lvalue-to-rvalue conversion here for class types,
5039 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5040 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5041 regions. */
5054 /* [expr.cond]
5056 After those conversions, one of the following shall hold:
5058 --The second and third operands have the same type; the result is of
5059 that type. */
5062 /* [expr.cond]
5064 --The second and third operands have arithmetic or enumeration
5065 type; the usual arithmetic conversions are performed to bring
5066 them to a common type, and the result is of that type. */
5071 {
5072 /* In this case, there is always a common type. */
5074 arg3_type);
5077 "implicit conversion from %qT to %qT to "
5079 loc);
5083 {
5087 /* Two enumerators from the same enumeration can have different
5093 }
5100 {
5104 }
5108 }
5109 /* [expr.cond]
5111 --The second and third operands have pointer type, or one has
5112 pointer type and the other is a null pointer constant; pointer
5113 conversions (_conv.ptr_) and qualification conversions
5114 (_conv.qual_) are performed to bring them to their composite
5115 pointer type (_expr.rel_). The result is of the composite
5116 pointer type.
5118 --The second and third operands have pointer to member type, or
5119 one has pointer to member type and the other is a null pointer
5120 constant; pointer to member conversions (_conv.mem_) and
5121 qualification conversions (_conv.qual_) are performed to bring
5122 them to a common type, whose cv-qualification shall match the
5123 cv-qualification of either the second or the third operand.
5124 The result is of the common type. */
5132 {
5135 complain);
5140 }
5143 {
5148 }
5153 valid_operands:
5156 /* We can't use result_type below, as fold might have returned a
5157 throw_expr. */
5160 {
5161 /* Expand both sides into the same slot, hopefully the target of
5162 the ?: expression. We used to check for TARGET_EXPRs here,
5163 but now we sometimes wrap them in NOP_EXPRs so the test would
5164 fail. */
5167 /* If this expression is an rvalue, but might be mistaken for an
5168 lvalue, we must add a NON_LVALUE_EXPR. */
5170 }
5171 else
5175 }
5177 /* Wrapper for above. */
5179 tree
5181 tsubst_flags_t complain)
5182 {
5183 tree ret;
5188 }
5190 /* OPERAND is an operand to an expression. Perform necessary steps
5191 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5192 returned. */
5194 static tree
5196 {
5198 {
5201 /* Make sure the template type is instantiated now. */
5203 }
5206 }
5208 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5209 OVERLOAD) to the CANDIDATES, returning an updated list of
5210 CANDIDATES. The ARGS are the arguments provided to the call;
5211 if FIRST_ARG is non-null it is the implicit object argument,
5212 otherwise the first element of ARGS is used if needed. The
5213 EXPLICIT_TARGS are explicit template arguments provided.
5214 TEMPLATE_ONLY is true if only template functions should be
5215 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5216 add_function_candidate. */
5218 static void
5220 tree return_type,
5225 tsubst_flags_t complain)
5226 {
5227 tree ctype;
5231 unification_kind_t strict;
5232 tree fn;
5237 /* Precalculate special handling of constructors and conversion ops. */
5240 {
5244 /* We're doing return_type(x). */
5246 else
5247 /* We're doing x.operator return_type(). */
5249 /* [over.match.funcs] For conversion functions, the function
5250 is considered to be a member of the class of the implicit
5251 object argument for the purpose of defining the type of
5252 the implicit object parameter. */
5254 }
5255 else
5256 {
5258 {
5260 /* For list-initialization we consider explicit constructors
5261 and complain if one is chosen. */
5262 check_converting
5265 }
5266 else
5267 {
5270 }
5273 }
5277 else
5278 /* Delay creating the implicit this parameter until it is needed. */
5282 {
5283 tree fn_first_arg;
5293 /* Figure out which set of arguments to use. */
5295 {
5296 /* If this function is a non-static member and we didn't get an
5297 implicit object argument, move it out of args. */
5299 {
5301 tree arg;
5308 }
5312 }
5313 else
5314 {
5315 /* Otherwise, just use the list of arguments provided. */
5318 }
5322 fn,
5323 ctype,
5324 explicit_targs,
5325 fn_first_arg,
5326 fn_args,
5327 return_type,
5328 access_path,
5329 conversion_path,
5330 flags,
5331 strict,
5332 complain);
5335 fn,
5336 ctype,
5337 fn_first_arg,
5338 fn_args,
5339 access_path,
5340 conversion_path,
5341 flags,
5342 complain);
5343 }
5344 }
5346 static tree
5349 {
5352 tree fnname;
5370 {
5374 }
5375 else
5382 {
5387 /* Use build_op_new_call and build_op_delete_call instead. */
5391 /* Use build_op_call instead. */
5398 /* These are saved for the sake of warn_logical_operator. */
5408 /* These are saved for the sake of maybe_warn_bool_compare. */
5413 /* =, ->, [], () must be non-static member functions. */
5424 }
5430 /* Use build_conditional_expr instead. */
5446 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5449 /* Add namespace-scope operators to the list of functions to
5450 consider. */
5462 /* Add class-member operators to the candidate set. */
5464 {
5465 tree fns;
5469 {
5472 }
5480 }
5481 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5482 only non-member functions that have type T1 or reference to
5483 cv-qualified-opt T1 for the first argument, if the first argument
5484 has an enumeration type, or T2 or reference to cv-qualified-opt
5485 T2 for the second argument, if the second argument has an
5486 enumeration type. Filter out those that don't match. */
5488 {
5492 {
5502 {
5508 && (same_type_ignoring_top_level_qualifiers_p
5513 }
5515 /* No argument has an appropriate type, so remove this
5516 candidate function from the list. */
5518 {
5521 }
5522 }
5523 }
5529 {
5532 /* For these, the built-in candidates set is empty
5533 [over.match.oper]/3. We don't want non-strict matches
5534 because exact matches are always possible with built-in
5535 operators. The built-in candidate set for COMPONENT_REF
5536 would be empty too, but since there are no such built-in
5537 operators, we accept non-strict matches for them. */
5544 }
5548 {
5550 {
5553 /* Don't try anything fancy if we're not allowed to produce
5554 errors. */
5558 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5559 distinguish between prefix and postfix ++ and
5560 operator++() was used for both, so we allow this with
5561 -fpermissive. */
5562 else
5563 {
5569 }
5576 else
5582 /* The caller will deal with these. */
5592 {
5593 /* If one of the arguments of the operator represents
5594 an invalid use of member function pointer, try to report
5595 a meaningful error ... */
5600 else
5601 {
5602 /* ... Otherwise, report the more generic
5603 "no matching operator found" error */
5606 }
5607 }
5610 }
5611 }
5612 else
5613 {
5616 {
5618 {
5621 }
5623 }
5625 {
5631 else
5633 }
5634 else
5635 {
5636 /* Give any warnings we noticed during overload resolution. */
5638 {
5642 }
5644 /* Check for comparison of different enum types. */
5646 {
5658 {
5662 }
5666 }
5668 /* We need to strip any leading REF_BIND so that bitfields
5669 don't cause errors. This should not remove any important
5670 conversions, because builtins don't apply to class
5671 objects directly. */
5678 {
5682 else
5685 /* We need to call warn_logical_operator before
5686 converting arg2 to a boolean_type, but after
5687 decaying an enumerator to its value. */
5694 }
5696 {
5701 }
5703 }
5704 }
5706 user_defined_result_ready:
5708 /* Free all the conversions we allocated. */
5714 builtin:
5716 {
5731 /* Fall through. */
5745 /* Fall through. */
5778 complain),
5781 /* The caller will deal with these. */
5789 }
5791 }
5793 /* Wrapper for above. */
5795 tree
5799 {
5800 tree ret;
5806 }
5808 /* Returns true if FN has two parameters, of which the second has type
5809 size_t. */
5811 static bool
5813 {
5818 }
5820 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5821 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5823 bool
5825 {
5826 /* A template instance is never a usual deallocation function,
5827 regardless of its signature. */
5832 /* If a class T has a member deallocation function named operator delete
5833 with exactly one parameter, then that function is a usual
5834 (non-placement) deallocation function. If class T does not declare
5835 such an operator delete but does declare a member deallocation
5836 function named operator delete with exactly two parameters, the second
5837 of which has type std::size_t (18.2), then this function is a usual
5838 deallocation function. */
5845 }
5847 /* Build a call to operator delete. This has to be handled very specially,
5848 because the restrictions on what signatures match are different from all
5849 other call instances. For a normal delete, only a delete taking (void *)
5850 or (void *, size_t) is accepted. For a placement delete, only an exact
5851 match with the placement new is accepted.
5853 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5854 ADDR is the pointer to be deleted.
5855 SIZE is the size of the memory block to be deleted.
5856 GLOBAL_P is true if the delete-expression should not consider
5857 class-specific delete operators.
5858 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5860 If this call to "operator delete" is being generated as part to
5861 deallocate memory allocated via a new-expression (as per [expr.new]
5862 which requires that if the initialization throws an exception then
5863 we call a deallocation function), then ALLOC_FN is the allocation
5864 function. */
5866 tree
5870 {
5884 /* In [class.free]
5886 If the result of the lookup is ambiguous or inaccessible, or if
5887 the lookup selects a placement deallocation function, the
5888 program is ill-formed.
5890 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5891 {
5895 }
5896 else
5902 /* Strip const and volatile from addr. */
5906 {
5907 /* "A declaration of a placement deallocation function matches the
5908 declaration of a placement allocation function if it has the same
5909 number of parameters and, after parameter transformations (8.3.5),
5910 all parameter types except the first are identical."
5912 So we build up the function type we want and ask instantiate_type
5913 to get it for us. */
5925 /* "If the lookup finds the two-parameter form of a usual deallocation
5926 function (3.7.4.2) and that function, considered as a placement
5927 deallocation function, would have been selected as a match for the
5928 allocation function, the program is ill-formed." */
5930 {
5938 /* But if the class has an operator delete (void *), then that is
5939 the usual deallocation function, so we shouldn't complain
5940 about using the operator delete (void *, size_t). */
5944 {
5949 }
5950 /* Before C++14 a two-parameter global deallocation function is
5951 always a placement deallocation function, but warn if
5952 -Wc++14-compat. */
5954 {
5959 }
5962 {
5964 {
5965 /* Only mention C++14 for namespace-scope delete. */
5968 else
5970 "%qD is a usual (non-placement) deallocation "
5972 }
5973 }
5974 else
5976 ok:;
5977 }
5978 }
5979 else
5980 /* "Any non-placement deallocation function matches a non-placement
5981 allocation function. If the lookup finds a single matching
5982 deallocation function, that function will be called; otherwise, no
5983 deallocation function will be called." */
5986 {
5989 {
5991 /* "If a class T has a member deallocation function named
5992 operator delete with exactly one parameter, then that
5993 function is a usual (non-placement) deallocation
5994 function. If class T does not declare such an operator
5995 delete but does declare a member deallocation function named
5996 operator delete with exactly two parameters, the second of
5997 which has type std::size_t (18.2), then this function is a
5998 usual deallocation function."
6000 So in a class (void*) beats (void*, size_t). */
6002 {
6005 }
6006 /* At global scope (in C++14 and above) the rules are different:
6008 If deallocation function lookup finds both a usual
6009 deallocation function with only a pointer parameter and a
6010 usual deallocation function with both a pointer parameter
6011 and a size parameter, the function to be called is selected
6012 as follows:
6014 * If the type is complete and if, for the second alternative
6015 (delete array) only, the operand is a pointer to a class
6016 type with a non-trivial destructor or a (possibly
6017 multi-dimensional) array thereof, the function with two
6018 parameters is selected.
6020 * Otherwise, it is unspecified which of the two deallocation
6021 functions is selected. */
6022 else
6023 {
6027 /* We need a cookie to determine the array size. */
6032 }
6033 }
6034 }
6036 /* If we have a matching function, call it. */
6038 {
6041 /* If the FN is a member function, make sure that it is
6042 accessible. */
6045 complain);
6047 /* Core issue 901: It's ok to new a type with deleted delete. */
6052 {
6053 /* The placement args might not be suitable for overload
6054 resolution at this point, so build the call directly. */
6064 }
6065 else
6066 {
6067 tree ret;
6075 }
6076 }
6078 /* [expr.new]
6080 If no unambiguous matching deallocation function can be found,
6081 propagating the exception does not cause the object's memory to
6082 be freed. */
6084 {
6088 alloc_fn);
6090 }
6096 }
6098 /* If the current scope isn't allowed to access DECL along
6099 BASETYPE_PATH, give an error. The most derived class in
6100 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6101 the declaration to use in the error diagnostic. */
6103 bool
6105 tsubst_flags_t complain)
6106 {
6110 {
6112 {
6114 {
6118 }
6120 {
6124 }
6125 else
6126 {
6129 }
6130 }
6132 }
6135 }
6137 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6138 bitwise or of LOOKUP_* values. If any errors are warnings are
6139 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6140 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6141 to NULL. */
6143 static tree
6146 {
6159 else
6162 }
6164 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6165 EXPR is implicitly converted to type TOTYPE.
6166 FN and ARGNUM are used for diagnostics. */
6168 static void
6170 {
6171 /* Issue warnings about peculiar, but valid, uses of NULL. */
6174 {
6175 source_location loc =
6182 else
6185 }
6187 /* Issue warnings if "false" is converted to a NULL pointer */
6190 {
6193 "converting %<false%> to pointer type for argument %P "
6195 else
6198 }
6199 }
6201 /* We gave a diagnostic during a conversion. If this was in the second
6202 standard conversion sequence of a user-defined conversion sequence, say
6203 which user-defined conversion. */
6205 static void
6207 {
6211 {
6215 }
6216 }
6218 /* Perform the conversions in CONVS on the expression EXPR. FN and
6219 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6220 indicates the `this' argument of a method. INNER is nonzero when
6221 being called to continue a conversion chain. It is negative when a
6222 reference binding will be applied, positive otherwise. If
6223 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6224 conversions will be emitted if appropriate. If C_CAST_P is true,
6225 this conversion is coming from a C-style cast; in that case,
6226 conversions to inaccessible bases are permitted. */
6228 static tree
6232 {
6234 diagnostic_t diag_kind;
6250 {
6254 /* Give a helpful error if this is bad because of excess braces. */
6259 {
6265 }
6267 /* Give a helpful error if this is bad because a conversion to bool
6268 from std::nullptr_t requires direct-initialization. */
6276 {
6278 {
6281 totype);
6287 complain);
6291 complain);
6292 else
6298 }
6300 {
6304 complain);
6306 }
6311 complain);
6314 }
6323 }
6329 {
6331 {
6336 /* When converting from an init list we consider explicit
6337 constructors, but actually trying to call one is an error. */
6339 /* Unless this is for direct-list-initialization. */
6341 /* And in C++98 a default constructor can't be explicit. */
6343 {
6349 {
6355 }
6356 else
6359 }
6361 /* If we're initializing from {}, it's value-initialization. */
6365 {
6370 {
6373 }
6375 }
6379 /* Set user_conv_p on the argument conversions, so rvalue/base
6380 handling knows not to allow any more UDCs. */
6386 /* If this is a constructor or a function returning an aggr type,
6387 we need to build up a TARGET_EXPR. */
6389 {
6392 /* Remember that this was list-initialization. */
6395 }
6398 }
6401 {
6407 else
6409 }
6414 /* Convert a constant to its underlying value, unless we are
6415 about to bind it to a reference, in which case we need to
6416 leave it as an lvalue. */
6418 {
6421 /* If __null has been converted to an integer type, we do not
6422 want to warn about uses of EXPR as an integer, rather than
6423 as a pointer. */
6425 }
6428 /* We leave bad_p off ck_ambig because overload resolution considers
6429 it valid, it just fails when we try to perform it. So we need to
6430 check complain here, too. */
6432 {
6433 /* Call build_user_type_conversion again for the error. */
6435 complain);
6439 }
6443 {
6444 /* Conversion to std::initializer_list<T>. */
6452 /* Convert all the elements. */
6454 {
6465 }
6466 /* Build up the array. */
6467 elttype = cp_build_qualified_type
6471 /* Take the address explicitly rather than via decay_conversion
6472 to avoid the error about taking the address of a temporary. */
6478 /* Build up the initializer_list object. */
6486 }
6490 {
6499 }
6502 complain);
6509 };
6514 c_cast_p,
6515 complain);
6520 {
6528 /* Else fall through. */
6531 {
6532 /* We are going to bind a reference directly to a base-class
6533 subobject of EXPR. */
6534 /* Build an expression for `*((base*) &expr)'. */
6538 }
6540 /* Copy-initialization where the cv-unqualified version of the source
6541 type is the same class as, or a derived class of, the class of the
6542 destination [is treated as direct-initialization]. [dcl.init] */
6545 /* This conversion is being done in the context of a user-defined
6546 conversion (i.e. the second step of copy-initialization), so
6547 don't allow any more. */
6549 else
6555 /* Copy-list-initialization doesn't actually involve a copy. */
6559 {
6564 }
6569 {
6573 {
6586 else
6593 }
6595 /* If necessary, create a temporary.
6597 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6598 that need temporaries, even when their types are reference
6599 compatible with the type of reference being bound, so the
6600 upcoming call to cp_build_addr_expr doesn't fail. */
6604 {
6605 /* Otherwise, a temporary of type "cv1 T1" is created and
6606 initialized from the initializer expression using the rules
6607 for a non-reference copy-initialization (8.5). */
6616 {
6617 /* If the reference is volatile or non-const, we
6618 cannot create a temporary. */
6625 else
6629 }
6630 /* If the source is a packed field, and we must use a copy
6631 constructor, then building the target expr will require
6632 binding the field to the reference parameter to the
6633 copy constructor, and we'll end up with an infinite
6634 loop. If we can use a bitwise copy, then we'll be
6635 OK. */
6639 {
6643 }
6645 {
6648 }
6650 }
6652 /* Take the address of the thing to which we will bind the
6653 reference. */
6658 /* Convert it to a pointer to the type referred to by the
6659 reference. This will adjust the pointer if a derived to
6660 base conversion is being performed. */
6663 /* Convert the pointer to the desired reference type. */
6665 }
6671 /* ??? Should the address of a transaction-safe pointer point to the TM
6672 clone, and this conversion look up the primary function? */
6676 /* Warn about deprecated conversion if appropriate. */
6692 }
6700 else
6704 }
6706 /* ARG is being passed to a varargs function. Perform any conversions
6707 required. Return the converted value. */
6709 tree
6711 {
6712 tree arg_type;
6715 /* [expr.call]
6717 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6718 standard conversions are performed. */
6721 /* [expr.call]
6723 If the argument has integral or enumeration type that is subject
6724 to the integral promotions (_conv.prom_), or a floating point
6725 type that is subject to the floating point promotion
6726 (_conv.fpprom_), the value of the argument is converted to the
6727 promoted type before the call. */
6732 {
6736 "implicit conversion from %qT to %qT when passing "
6740 }
6744 {
6746 {
6748 complain);
6758 }
6759 else
6761 }
6767 /* In a template (or ill-formed code), we can have an incomplete type
6768 even after require_complete_type_sfinae, in which case we don't know
6769 whether it has trivial copy or not. */
6771 {
6772 /* Build up a real lvalue-to-rvalue conversion in case the
6773 copy constructor is trivial but not callable. */
6777 /* [expr.call] 5.2.2/7:
6778 Passing a potentially-evaluated argument of class type (Clause 9)
6779 with a non-trivial copy constructor or a non-trivial destructor
6780 with no corresponding parameter is conditionally-supported, with
6781 implementation-defined semantics.
6783 We support it as pass-by-invisible-reference, just like a normal
6784 value parameter.
6786 If the call appears in the context of a sizeof expression,
6787 it is not potentially-evaluated. */
6791 {
6794 "passing objects of non-trivially-copyable "
6796 arg_type);
6798 }
6799 }
6802 }
6804 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6806 tree
6808 {
6810 {
6814 }
6824 {
6827 }
6831 {
6832 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6833 it as pass by invisible reference. */
6835 "receiving objects of non-trivially-copyable type %q#T "
6841 }
6844 }
6846 /* TYPE has been given to va_arg. Apply the default conversions which
6847 would have happened when passed via ellipsis. Return the promoted
6848 type, or the passed type if there is no change. */
6850 tree
6852 {
6853 tree promote;
6855 /* Perform the array-to-pointer and function-to-pointer
6856 conversions. */
6864 }
6866 /* ARG is a default argument expression being passed to a parameter of
6867 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6868 zero-based argument number. Do any required conversions. Return
6869 the converted value. */
6872 void
6876 void
6880 tree
6882 tsubst_flags_t complain)
6883 {
6885 tree t;
6887 /* See through clones. */
6890 /* Detect recursion. */
6893 {
6897 }
6899 /* If the ARG is an unparsed default argument expression, the
6900 conversion cannot be performed. */
6902 {
6907 }
6914 /* Due to:
6916 [dcl.fct.default]
6918 The names in the expression are bound, and the semantic
6919 constraints are checked, at the point where the default
6920 expressions appears.
6922 we must not perform access checks here. */
6924 /* We must make a copy of ARG, in case subsequent processing
6925 alters any part of it. */
6929 complain);
6936 }
6938 /* Returns the type which will really be used for passing an argument of
6939 type TYPE. */
6941 tree
6943 {
6944 /* Pass classes with copy ctors by invisible reference. */
6946 {
6948 /* There are no other pointers to this temporary. */
6950 }
6958 }
6960 /* Actually perform the appropriate conversion. */
6962 tree
6964 {
6965 tree bitfield_type;
6967 /* If VAL is a bitfield, then -- since it has already been converted
6968 to TYPE -- it cannot have a precision greater than TYPE.
6970 If it has a smaller precision, we must widen it here. For
6971 example, passing "int f:3;" to a function expecting an "int" will
6972 not result in any conversion before this point.
6974 If the precision is the same we must not risk widening. For
6975 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6976 often have type "int", even though the C++ type for the field is
6977 "long long". If the value is being passed to a function
6978 expecting an "int", then no conversions will be required. But,
6979 if we call convert_bitfield_to_declared_type, the bitfield will
6980 be converted to "long long". */
6987 ;
6988 /* Pass classes with copy ctors by invisible reference. */
6998 {
7007 }
7009 }
7011 /* Returns true iff FN is a function with magic varargs, i.e. ones for
7012 which no conversions at all should be done. This is true for some
7013 builtins which don't act like normal functions. */
7015 bool
7017 {
7023 {
7033 }
7036 }
7038 /* Returns the decl of the dispatcher function if FN is a function version. */
7040 tree
7042 {
7052 {
7056 }
7061 }
7063 /* fn is a function version dispatcher that is marked used. Mark all the
7064 semantically identical function versions it will dispatch as used. */
7066 void
7068 {
7085 /* All semantically identical versions are chained. Traverse and mark each
7086 one of them as used. */
7089 {
7092 }
7093 }
7095 /* Build a call to "the copy constructor" for the type of A, even if it
7096 wouldn't be selected by normal overload resolution. Used for
7097 diagnostics. */
7099 static tree
7101 {
7112 }
7114 /* Return true iff T refers to a base field. */
7116 static bool
7118 {
7127 }
7129 /* We can't elide a copy from a function returning by value to a base
7130 subobject, as the callee might clobber tail padding. Return true iff this
7131 could be that case. */
7133 static bool
7135 {
7145 }
7147 /* Subroutine of the various build_*_call functions. Overload resolution
7148 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7149 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7150 bitmask of various LOOKUP_* flags which apply to the call itself. */
7152 static tree
7154 {
7162 tree val;
7171 /* In a template, there is no need to perform all of the work that
7172 is normally done. We are only interested in the type of the call
7173 expression, i.e., the return type of the function. Any semantic
7174 errors will be deferred until the template is instantiated. */
7176 {
7178 tree return_type;
7186 else
7187 {
7190 tree arg;
7198 }
7208 }
7210 /* Give any warnings we noticed during overload resolution. */
7212 {
7216 }
7218 /* Make =delete work with SFINAE. */
7223 {
7224 tree access_fn;
7225 /* If FN is a template function, two cases must be considered.
7226 For example:
7228 struct A {
7229 protected:
7230 template <class T> void f();
7231 };
7232 template <class T> struct B {
7233 protected:
7234 void g();
7235 };
7236 struct C : A, B<int> {
7237 using A::f; // #1
7238 using B<int>::g; // #2
7239 };
7241 In case #1 where `A::f' is a member template, DECL_ACCESS is
7242 recorded in the primary template but not in its specialization.
7243 We check access of FN using its primary template.
7245 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7246 because it is a member of class template B, DECL_ACCESS is
7247 recorded in the specialization `B<int>::g'. We cannot use its
7248 primary template because `B<T>::g' and `B<int>::g' may have
7249 different access. */
7253 else
7258 }
7260 /* If we're checking for implicit delete, don't bother with argument
7261 conversions. */
7263 {
7265 {
7269 }
7273 /* Reject bad conversions now. */
7275 /* else continue to get conversion error. */
7276 }
7278 /* N3276 magic doesn't apply to nested calls. */
7282 /* Find maximum size of vector to hold converted arguments. */
7289 /* The implicit parameters to a constructor are not considered by overload
7290 resolution, and must be of the proper type. */
7292 {
7293 tree object_arg;
7295 {
7298 }
7299 else
7300 {
7303 }
7306 /* We should never try to call the abstract constructor. */
7310 {
7314 }
7315 }
7316 /* Bypass access control for 'this' parameter. */
7318 {
7321 ? first_arg
7324 tree converted_arg;
7325 tree base_binfo;
7328 {
7330 {
7335 }
7336 else
7338 }
7340 /* See if the function member or the whole class type is declared
7341 final and the call can be devirtualized. */
7346 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7347 X is called for an object that is not of type X, or of a type
7348 derived from X, the behavior is undefined.
7350 So we can assume that anything passed as 'this' is non-null, and
7351 optimize accordingly. */
7353 /* Convert to the base in which the function was declared. */
7356 arg,
7359 /* Check that the base class is accessible. */
7362 {
7367 else
7369 }
7370 /* If fn was found by a using declaration, the conversion path
7371 will be to the derived class, not the base declaring fn. We
7372 must convert from derived to base. */
7383 else
7387 }
7392 {
7399 /* If the argument is NULL and used to (implicitly) instantiate a
7400 template function (and bind one of the template arguments to
7401 the type of 'long int'), we don't want to warn about passing NULL
7402 to non-pointer argument.
7403 For example, if we have this template function:
7405 template<typename T> void func(T x) {}
7407 we want to warn (when -Wconversion is enabled) in this case:
7409 void foo() {
7410 func<int>(NULL);
7411 }
7413 but not in this case:
7415 void foo() {
7416 func(NULL);
7417 }
7418 */
7425 /* Warn about initializer_list deduction that isn't currently in the
7426 working draft. */
7428 && flag_deduce_init_list
7432 {
7445 {
7453 }
7454 }
7456 conversion_warning
7457 ? complain
7464 else
7466 }
7468 /* Default arguments */
7470 {
7476 complain);
7477 }
7479 /* Ellipsis */
7481 {
7484 /* Do no conversions for magic varargs. */
7489 {
7490 /* Avoid infinite recursion trying to call A(...). */
7492 /* Try to call the actual copy constructor for a good error. */
7495 }
7496 else
7499 }
7504 /* Avoid to do argument-transformation, if warnings for format, and for
7505 nonnull are disabled. Just in case that at least one of them is active
7506 the check_function_arguments function might warn about something. */
7509 {
7516 }
7518 /* Avoid actually calling copy constructors and copy assignment operators,
7519 if possible. */
7526 /* It's unsafe to elide the constructor when handling
7527 a noexcept-expression, it may evaluate to the wrong
7528 value (c++/53025). */
7530 {
7531 tree targ;
7533 tree fa;
7536 /* Pull out the real argument, disregarding const-correctness. */
7542 {
7547 }
7548 else
7553 else
7556 /* [class.copy]: the copy constructor is implicitly defined even if
7557 the implementation elided its use. */
7559 {
7563 }
7565 /* If we're creating a temp and we already have one, don't create a
7566 new one. If we're not creating a temp but we get one, use
7567 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7568 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7569 temp or an INIT_EXPR otherwise. */
7572 {
7577 }
7581 {
7583 complain));
7587 }
7588 }
7592 {
7593 tree to = stabilize_reference
7600 {
7601 /* Avoid copying empty classes. */
7606 }
7608 {
7611 }
7612 else
7613 {
7614 /* We must only copy the non-tail padding parts. */
7622 build_index_type
7631 }
7634 }
7639 /* FIXME handle trivial default constructor, too. */
7641 /* For calls to a multi-versioned function, overload resolution
7642 returns the function with the highest target priority, that is,
7643 the version that will checked for dispatching first. If this
7644 version is inlinable, a direct call to this version can be made
7645 otherwise the call should go through the dispatcher. */
7650 {
7656 }
7663 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7664 virtual functions can't be constexpr. */
7666 {
7667 tree t;
7674 complain);
7680 else
7683 }
7684 else
7685 {
7689 }
7696 }
7698 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7699 This function performs no overload resolution, conversion, or other
7700 high-level operations. */
7702 tree
7704 tsubst_flags_t complain)
7705 {
7706 tree fndecl;
7708 /* Remember roughly where this call is. */
7715 /* Check that arguments to builtin functions match the expectations. */
7719 {
7722 /* We need to take care that values to BUILT_IN_NORMAL
7723 are reduced. */
7729 }
7731 /* If it is a built-in array notation function, then the return type of
7732 the function is the element type of the array passed in as array
7733 notation (i.e. the first parameter of the function). */
7735 {
7744 {
7746 {
7749 }
7750 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7751 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7752 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7753 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7754 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7755 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7756 The pre-defined return-type is the correct one. */
7760 }
7761 }
7766 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7767 function call is either the operand of a decltype-specifier or the
7768 right operand of a comma operator that is the operand of a
7769 decltype-specifier, a temporary object is not introduced for the
7770 prvalue. The type of the prvalue may be incomplete. */
7772 {
7779 }
7781 }
7785 /* Make an expression which yields the address of the Java interface
7786 method FN. This is achieved by generating a call to libjava's
7787 _Jv_LookupInterfaceMethodIdx(). */
7789 static tree
7791 {
7797 {
7801 java_iface_lookup_fn
7804 }
7806 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7807 This is the first entry in the vtable. */
7809 tf_warning_or_error),
7810 integer_zero_node);
7812 /* Get the java.lang.Class pointer for the interface being called. */
7817 {
7819 iface);
7821 }
7825 /* Determine the itable index of FN. */
7828 {
7833 i++;
7834 }
7839 java_iface_lookup_fn);
7842 }
7844 /* Returns the value to use for the in-charge parameter when making a
7845 call to a function with the indicated NAME.
7847 FIXME:Can't we find a neater way to do this mapping? */
7849 tree
7851 {
7862 /* This function should only be called with one of the names listed
7863 above. */
7866 }
7868 /* Build a call to a constructor, destructor, or an assignment
7869 operator for INSTANCE, an expression with class type. NAME
7870 indicates the special member function to call; *ARGS are the
7871 arguments. ARGS may be NULL. This may change ARGS. BINFO
7872 indicates the base of INSTANCE that is to be passed as the `this'
7873 parameter to the member function called.
7875 FLAGS are the LOOKUP_* flags to use when processing the call.
7877 If NAME indicates a complete object constructor, INSTANCE may be
7878 NULL_TREE. In this case, the caller will call build_cplus_new to
7879 store the newly constructed object into a VAR_DECL. */
7881 tree
7884 {
7885 tree fns;
7886 /* The type of the subobject to be constructed or destroyed. */
7887 tree class_type;
7889 tree ret;
7898 {
7899 /* Resolve the name. */
7904 }
7910 /* Handle the special case where INSTANCE is NULL_TREE. */
7913 else
7914 {
7920 /* Convert to the base class, if necessary. */
7923 {
7925 /* For constructors and destructors, either the base is
7926 non-virtual, or it is virtual but we are doing the
7927 conversion from a constructor or destructor for the
7928 complete object. In either case, we can convert
7929 statically. */
7931 else
7932 /* However, for assignment operators, we must convert
7933 dynamically if the base is virtual. */
7936 }
7937 }
7943 /* When making a call to a constructor or destructor for a subobject
7944 that uses virtual base classes, pass down a pointer to a VTT for
7945 the subobject. */
7949 {
7950 tree vtt;
7951 tree sub_vtt;
7953 /* If the current function is a complete object constructor
7954 or destructor, then we fetch the VTT directly.
7955 Otherwise, we look it up using the VTT we were given. */
7963 current_vtt_parm,
7964 vtt);
7967 else
7971 {
7974 }
7977 }
7982 complain);
7996 }
7998 /* Return the NAME, as a C string. The NAME indicates a function that
7999 is a member of TYPE. *FREE_P is set to true if the caller must
8000 free the memory returned.
8002 Rather than go through all of this, we should simply set the names
8003 of constructors and destructors appropriately, and dispense with
8004 ctor_identifier, dtor_identifier, etc. */
8008 {
8011 /* Assume that we will not allocate memory. */
8013 /* Constructors and destructors are special. */
8015 {
8016 pretty_name
8018 /* For a destructor, add the '~'. */
8022 {
8024 /* Remember that we need to free the memory allocated. */
8026 }
8027 }
8029 {
8032 TFF_PLAIN_IDENTIFIER),
8033 NULL);
8034 /* Remember that we need to free the memory allocated. */
8036 }
8037 else
8041 }
8043 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8044 be set, upon return, to the function called. ARGS may be NULL.
8045 This may change ARGS. */
8047 static tree
8051 {
8056 tree optype;
8058 tree name;
8061 tree call;
8062 tree fn;
8065 tree orig_instance;
8066 tree orig_fns;
8072 /* We don't know what function we're going to call, yet. */
8081 {
8085 }
8090 /* Dismantle the baselink to collect all the information we need. */
8098 {
8102 }
8113 {
8118 }
8121 /* Under DR 147 A::A() is an invalid constructor call,
8122 not a functional cast. */
8124 {
8134 complain);
8136 }
8138 /* Figure out whether to skip the first argument for the error
8139 message we will display to users if an error occurs. We don't
8140 want to display any compiler-generated arguments. The "this"
8141 pointer hasn't been added yet. However, we must remove the VTT
8142 pointer if this is a call to a base-class constructor or
8143 destructor. */
8146 {
8147 /* Callers should explicitly indicate whether they want to construct
8148 the complete object or just the part without virtual bases. */
8150 /* Similarly for destructors. */
8152 /* Remove the VTT pointer, if present. */
8156 }
8158 /* Process the argument list. */
8160 {
8164 }
8166 /* Consider the object argument to be used even if we end up selecting a
8167 static member function. */
8170 /* It's OK to call destructors and constructors on cv-qualified objects.
8171 Therefore, convert the INSTANCE to the unqualified type, if
8172 necessary. */
8175 {
8177 {
8181 }
8182 }
8186 /* For the overload resolution we need to find the actual `this`
8187 that would be captured if the call turns out to be to a
8188 non-static member function. Do not actually capture it at this
8189 point. */
8191 /* Constructors don't use the enclosing 'this'. */
8193 else
8196 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8199 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8200 initializer, not T({ }). */
8203 {
8210 /* If the initializer list has no elements and T is a class type with
8211 a default constructor, the object is value-initialized. Handle
8212 this here so we don't need to handle it wherever we use
8213 build_special_member_call. */
8216 /* For a user-provided default constructor, use the normal
8217 mechanisms so that protected access works. */
8222 /* If BASETYPE is an aggregate, we need to do aggregate
8223 initialization. */
8225 {
8228 }
8231 {
8237 }
8239 /* Otherwise go ahead with overload resolution. */
8244 }
8245 else
8246 {
8250 }
8255 {
8257 {
8264 else
8265 {
8268 tree arglist;
8279 }
8281 }
8283 }
8284 else
8285 {
8288 {
8291 tree arglist;
8294 {
8302 else
8308 }
8310 }
8311 else
8312 {
8320 {
8321 /* This is not an error, it is runtime undefined
8322 behavior. */
8331 fn);
8332 }
8337 {
8342 {
8343 /* We captured 'this' in the current lambda now that
8344 we know we really need it. */
8346 }
8347 else
8348 {
8351 fn);
8353 }
8354 }
8357 {
8358 /* Optimize away vtable lookup if we know that this
8359 function can't be overridden. We need to check if
8360 the context and the type where we found fn are the same,
8361 actually FN might be defined in a different class
8362 type because of a using-declaration. In this case, we
8363 do not want to perform a non-virtual call. */
8365 && same_type_ignoring_top_level_qualifiers_p
8371 /* Now we know what function is being called. */
8374 /* Build the actual CALL_EXPR. */
8376 /* In an expression of the form `a->f()' where `f' turns
8377 out to be a static member function, `a' is
8378 none-the-less evaluated. */
8387 /* An explicit call of the form "x->~X()" has type
8388 "void". However, on platforms where destructors
8389 return "this" (i.e., those where
8390 targetm.cxx.cdtor_returns_this is true), such calls
8391 will appear to have a return value of pointer type
8392 to the low-level call machinery. We do not want to
8393 change the low-level machinery, since we want to be
8394 able to optimize "delete f()" on such platforms as
8395 "operator delete(~X(f()))" (rather than generating
8396 "t = f(), ~X(t), operator delete (t)"). */
8398 }
8399 }
8400 }
8403 {
8409 {
8412 }
8415 call = (build_min_non_dep_call_vec
8419 orig_args));
8424 }
8426 /* Free all the conversions we allocated. */
8433 }
8435 /* Wrapper for above. */
8437 tree
8441 {
8442 tree ret;
8448 }
8450 /* Returns true iff standard conversion sequence ICS1 is a proper
8451 subsequence of ICS2. */
8453 static bool
8455 {
8456 /* We can assume that a conversion of the same code
8457 between the same types indicates a subsequence since we only get
8458 here if the types we are converting from are the same. */
8465 {
8475 /* At this point, ICS1 cannot be a proper subsequence of
8476 ICS2. We can get a USER_CONV when we are comparing the
8477 second standard conversion sequence of two user conversion
8478 sequences. */
8488 }
8489 }
8491 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8492 be any _TYPE nodes. */
8494 bool
8496 {
8500 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8501 considers every class derived from itself. */
8504 }
8506 /* We build the ICS for an implicit object parameter as a pointer
8507 conversion sequence. However, such a sequence should be compared
8508 as if it were a reference conversion sequence. If ICS is the
8509 implicit conversion sequence for an implicit object parameter,
8510 modify it accordingly. */
8512 static void
8514 {
8516 {
8517 /* [over.match.funcs]
8519 For non-static member functions, the type of the
8520 implicit object parameter is "reference to cv X"
8521 where X is the class of which the function is a
8522 member and cv is the cv-qualification on the member
8523 function declaration. */
8525 tree reference_type;
8527 /* The `this' parameter is a pointer to a class type. Make the
8528 implicit conversion talk about a reference to that same class
8529 type. */
8542 }
8543 }
8545 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8546 and return the initial reference binding conversion. Otherwise,
8547 leave *ICS unchanged and return NULL. */
8551 {
8553 {
8558 }
8561 }
8563 /* Compare two implicit conversion sequences according to the rules set out in
8564 [over.ics.rank]. Return values:
8566 1: ics1 is better than ics2
8567 -1: ics2 is better than ics1
8568 0: ics1 and ics2 are indistinguishable */
8570 static int
8572 {
8573 tree from_type1;
8574 tree from_type2;
8575 tree to_type1;
8576 tree to_type2;
8583 /* REF_BINDING is nonzero if the result of the conversion sequence
8584 is a reference type. In that case REF_CONV is the reference
8585 binding conversion. */
8589 /* Compare badness before stripping the reference conversion. */
8595 /* Handle implicit object parameters. */
8599 /* Handle reference parameters. */
8603 /* List-initialization sequence L1 is a better conversion sequence than
8604 list-initialization sequence L2 if L1 converts to
8605 std::initializer_list<X> for some X and L2 does not. */
8611 /* [over.ics.rank]
8613 When comparing the basic forms of implicit conversion sequences (as
8614 defined in _over.best.ics_)
8616 --a standard conversion sequence (_over.ics.scs_) is a better
8617 conversion sequence than a user-defined conversion sequence
8618 or an ellipsis conversion sequence, and
8620 --a user-defined conversion sequence (_over.ics.user_) is a
8621 better conversion sequence than an ellipsis conversion sequence
8622 (_over.ics.ellipsis_). */
8623 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8624 mismatch. If both ICS are bad, we try to make a decision based on
8625 what would have happened if they'd been good. This is not an
8626 extension, we'll still give an error when we build up the call; this
8627 just helps us give a more helpful error message. */
8637 /* Both conversions are ellipsis conversions. */
8640 /* User-defined conversion sequence U1 is a better conversion sequence
8641 than another user-defined conversion sequence U2 if they contain the
8642 same user-defined conversion operator or constructor and if the sec-
8643 ond standard conversion sequence of U1 is better than the second
8644 standard conversion sequence of U2. */
8646 /* Handle list-conversion with the same code even though it isn't always
8647 ranked as a user-defined conversion and it doesn't have a second
8648 standard conversion sequence; it will still have the desired effect.
8649 Specifically, we need to do the reference binding comparison at the
8650 end of this function. */
8653 {
8669 {
8672 }
8673 else
8674 {
8675 /* For ambiguous or aggregate conversions, use the target type as
8676 a proxy for the conversion function. */
8679 }
8681 /* We can just fall through here, after setting up
8682 FROM_TYPE1 and FROM_TYPE2. */
8685 }
8686 else
8687 {
8691 /* We're dealing with two standard conversion sequences.
8693 [over.ics.rank]
8695 Standard conversion sequence S1 is a better conversion
8696 sequence than standard conversion sequence S2 if
8698 --S1 is a proper subsequence of S2 (comparing the conversion
8699 sequences in the canonical form defined by _over.ics.scs_,
8700 excluding any Lvalue Transformation; the identity
8701 conversion sequence is considered to be a subsequence of
8702 any non-identity conversion sequence */
8713 }
8715 /* One sequence can only be a subsequence of the other if they start with
8716 the same type. They can start with different types when comparing the
8717 second standard conversion sequence in two user-defined conversion
8718 sequences. */
8720 {
8725 }
8727 /* [over.ics.rank]
8729 Or, if not that,
8731 --the rank of S1 is better than the rank of S2 (by the rules
8732 defined below):
8734 Standard conversion sequences are ordered by their ranks: an Exact
8735 Match is a better conversion than a Promotion, which is a better
8736 conversion than a Conversion.
8738 Two conversion sequences with the same rank are indistinguishable
8739 unless one of the following rules applies:
8741 --A conversion that does not a convert a pointer, pointer to member,
8742 or std::nullptr_t to bool is better than one that does.
8744 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8745 so that we do not have to check it explicitly. */
8754 /* A conversion from scalar arithmetic type to complex is worse than a
8755 conversion between scalar arithmetic types. */
8762 {
8765 else
8767 }
8773 {
8778 }
8779 /* The rules for pointers to members A::* are just like the rules
8780 for pointers A*, except opposite: if B is derived from A then
8781 A::* converts to B::*, not vice versa. For that reason, we
8782 switch the from_ and to_ variables here. */
8789 {
8794 }
8799 {
8800 /* This was one of the pointer or pointer-like conversions.
8802 [over.ics.rank]
8804 --If class B is derived directly or indirectly from class A,
8805 conversion of B* to A* is better than conversion of B* to
8806 void*, and conversion of A* to void* is better than
8807 conversion of B* to void*. */
8810 {
8812 deref_from_type2))
8815 deref_from_type1))
8817 }
8820 {
8822 {
8824 {
8826 deref_to_type1))
8828 }
8829 /* We know that DEREF_TO_TYPE1 is `void' here. */
8831 deref_to_type2))
8833 }
8834 }
8837 {
8838 /* [over.ics.rank]
8840 --If class B is derived directly or indirectly from class A
8841 and class C is derived directly or indirectly from B,
8843 --conversion of C* to B* is better than conversion of C* to
8844 A*,
8846 --conversion of B* to A* is better than conversion of C* to
8847 A* */
8849 {
8851 deref_to_type2))
8854 deref_to_type1))
8856 }
8858 {
8860 deref_from_type1))
8863 deref_from_type2))
8865 }
8866 }
8867 }
8870 {
8873 /* [over.ics.rank]
8875 --binding of an expression of type C to a reference of type
8876 B& is better than binding an expression of type C to a
8877 reference of type A&
8879 --conversion of C to B is better than conversion of C to A, */
8882 {
8887 }
8888 }
8891 {
8894 /* [over.ics.rank]
8896 --binding of an expression of type B to a reference of type
8897 A& is better than binding an expression of type C to a
8898 reference of type A&,
8900 --conversion of B to A is better than conversion of C to A */
8903 {
8908 }
8909 }
8911 /* [over.ics.rank]
8913 --S1 and S2 differ only in their qualification conversion and yield
8914 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8915 qualification signature of type T1 is a proper subset of the cv-
8916 qualification signature of type T2 */
8920 {
8924 }
8926 /* [over.ics.rank]
8928 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8929 to an implicit object parameter of a non-static member function
8930 declared without a ref-qualifier, and either S1 binds an lvalue
8931 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8932 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8933 draft standard, 13.3.3.2)
8935 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8936 types to which the references refer are the same type except for
8937 top-level cv-qualifiers, and the type to which the reference
8938 initialized by S2 refers is more cv-qualified than the type to
8939 which the reference initialized by S1 refers.
8941 DR 1328 [over.match.best]: the context is an initialization by
8942 conversion function for direct reference binding (13.3.1.6) of a
8943 reference to function type, the return type of F1 is the same kind of
8944 reference (i.e. lvalue or rvalue) as the reference being initialized,
8945 and the return type of F2 is not. */
8948 {
8955 {
8959 /* Don't prefer a bad conversion that drops cv-quals to a bad
8960 conversion with the wrong rvalueness. */
8964 }
8967 {
8971 {
8972 /* Prefer the one that drops fewer cv-quals. */
8977 }
8979 }
8980 }
8982 /* Neither conversion sequence is better than the other. */
8984 }
8986 /* The source type for this standard conversion sequence. */
8988 static tree
8990 {
8992 {
8997 }
8999 }
9001 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9002 a pointer to LOSER and re-running joust to produce the warning if WINNER
9003 is actually used. */
9005 static void
9007 {
9013 }
9015 /* Compare two candidates for overloading as described in
9016 [over.match.best]. Return values:
9018 1: cand1 is better than cand2
9019 -1: cand2 is better than cand1
9020 0: cand1 and cand2 are indistinguishable */
9022 static int
9024 tsubst_flags_t complain)
9025 {
9031 /* Candidates that involve bad conversions are always worse than those
9032 that don't. */
9038 /* If we have two pseudo-candidates for conversions to the same type,
9039 or two candidates for the same function, arbitrarily pick one. */
9044 /* Prefer a non-deleted function over an implicitly deleted move
9045 constructor or assignment operator. This differs slightly from the
9046 wording for issue 1402 (which says the move op is ignored by overload
9047 resolution), but this way produces better error messages. */
9051 {
9058 }
9060 /* a viable function F1
9061 is defined to be a better function than another viable function F2 if
9062 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9063 ICSi(F2), and then */
9065 /* for some argument j, ICSj(F1) is a better conversion sequence than
9066 ICSj(F2) */
9068 /* For comparing static and non-static member functions, we ignore
9069 the implicit object parameter of the non-static function. The
9070 standard says to pretend that the static function has an object
9071 parm, but that won't work with operator overloading. */
9074 {
9080 /* We're comparing a near-match list constructor and a near-match
9081 non-list constructor. Just treat them as unordered. */
9088 else
9089 {
9092 }
9093 }
9096 {
9102 {
9104 && warn_sign_promo
9116 {
9123 else
9128 {
9132 }
9133 else
9135 }
9138 {
9141 }
9143 }
9144 }
9146 /* warn about confusing overload resolution for user-defined conversions,
9147 either between a constructor and a conversion op, or between two
9148 conversion ops. */
9153 {
9159 else
9162 /* We don't want to complain about `X::operator T1 ()'
9163 beating `X::operator T2 () const', when T2 is a no less
9164 cv-qualified version of T1. */
9167 {
9172 {
9175 }
9178 }
9179 else
9185 {
9192 {
9194 }
9195 }
9196 else
9198 }
9203 /* DR 495 moved this tiebreaker above the template ones. */
9204 /* or, if not that,
9205 the context is an initialization by user-defined conversion (see
9206 _dcl.init_ and _over.match.user_) and the standard conversion
9207 sequence from the return type of F1 to the destination type (i.e.,
9208 the type of the entity being initialized) is a better conversion
9209 sequence than the standard conversion sequence from the return type
9210 of F2 to the destination type. */
9213 {
9217 }
9219 /* or, if not that,
9220 F1 is a non-template function and F2 is a template function
9221 specialization. */
9228 /* or, if not that,
9229 F1 and F2 are template functions and the function template for F1 is
9230 more specialized than the template for F2 according to the partial
9231 ordering rules. */
9234 {
9235 winner = more_specialized_fn
9238 /* [temp.func.order]: The presence of unused ellipsis and default
9239 arguments has no effect on the partial ordering of function
9240 templates. add_function_candidate() will not have
9241 counted the "this" argument for constructors. */
9245 }
9247 // C++ Concepts
9248 // or, if not that, F1 is more constrained than F2.
9250 {
9254 }
9256 /* Check whether we can discard a builtin candidate, either because we
9257 have two identical ones or matching builtin and non-builtin candidates.
9259 (Pedantically in the latter case the builtin which matched the user
9260 function should not be added to the overload set, but we spot it here.
9262 [over.match.oper]
9263 ... the builtin candidates include ...
9264 - do not have the same parameter type list as any non-template
9265 non-member candidate. */
9268 {
9274 {
9276 /* Two built-in candidates; arbitrarily pick one. */
9279 /* cand1 is built-in; prefer cand2. */
9281 else
9282 /* cand2 is built-in; prefer cand1. */
9284 }
9285 }
9287 /* For candidates of a multi-versioned function, make the version with
9288 the highest priority win. This version will be checked for dispatching
9289 first. If this version can be inlined into the caller, the front-end
9290 will simply make a direct call to this function. */
9296 {
9302 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9303 is possible that cand1->fn and cand2->fn are function versions but of
9304 different functions. Check types to see if they are versions of the same
9305 function. */
9308 {
9309 /* Always make the version with the higher priority, more
9310 specialized, win. */
9314 else
9316 }
9317 }
9319 /* If the two function declarations represent the same function (this can
9320 happen with declarations in multiple scopes and arg-dependent lookup),
9321 arbitrarily choose one. But first make sure the default args we're
9322 using match. */
9325 {
9332 {
9333 /* Don't crash if the fn is variadic. */
9338 }
9346 {
9349 {
9351 {
9353 {
9355 "default argument mismatch in "
9357 {
9362 }
9363 }
9364 else
9366 }
9367 else
9370 }
9373 }
9376 }
9378 tweak:
9380 /* Extension: If the worst conversion for one candidate is worse than the
9381 worst conversion for the other, take the first. */
9383 {
9388 {
9393 }
9399 {
9400 /* Don't choose a deleted function over ambiguity. */
9404 {
9406 "ISO C++ says that these are ambiguous, even "
9407 "though the worst conversion for the first is better than "
9411 }
9412 else
9415 }
9416 }
9420 }
9422 /* Given a list of candidates for overloading, find the best one, if any.
9423 This algorithm has a worst case of O(2n) (winner is last), and a best
9424 case of O(n/2) (totally ambiguous); much better than a sorting
9425 algorithm. */
9429 {
9434 /* Walk through the list once, comparing each current champ to the next
9435 candidate, knocking out a candidate or two with each comparison. */
9438 {
9442 else
9443 {
9445 {
9450 }
9451 else
9452 {
9455 }
9458 }
9459 }
9461 /* Make sure the champ is better than all the candidates it hasn't yet
9462 been compared to. */
9465 challenger != champ
9468 {
9472 }
9475 }
9477 /* Returns nonzero if things of type FROM can be converted to TO. */
9479 bool
9481 {
9483 /* implicit_conversion only considers user-defined conversions
9484 if it has an expression for the call argument list. */
9488 }
9490 /* Returns nonzero if things of type FROM can be converted to TO with a
9491 standard conversion. */
9493 bool
9495 {
9497 }
9499 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9501 bool
9503 tsubst_flags_t complain)
9504 {
9509 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9511 /* We want to discard any access checks done for this test,
9512 as we might not be in the appropriate access context and
9513 we'll do the check again when we actually perform the
9514 conversion. */
9521 /* Discard the access checks now. */
9523 /* Free all the conversions we allocated. */
9527 }
9529 /* Like can_convert_arg, but allows dubious conversions as well. */
9531 bool
9533 tsubst_flags_t complain)
9534 {
9538 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9540 /* Try to perform the conversion. */
9543 /* Free all the conversions we allocated. */
9547 }
9549 /* Convert EXPR to TYPE. Return the converted expression.
9551 Note that we allow bad conversions here because by the time we get to
9552 this point we are committed to doing the conversion. If we end up
9553 doing a bad conversion, convert_like will complain. */
9555 tree
9558 {
9566 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9574 {
9576 {
9577 /* If expr has unknown type, then it is an overloaded function.
9578 Call instantiate_type to get good error messages. */
9583 else
9586 }
9588 }
9590 {
9591 /* In a template, we are only concerned about determining the
9592 type of non-dependent expressions, so we do not have to
9593 perform the actual conversion. But for initializers, we
9594 need to be able to perform it at instantiation
9595 (or instantiate_non_dependent_expr) time. */
9599 }
9600 else
9603 /* Free all the conversions we allocated. */
9607 }
9609 tree
9611 {
9613 LOOKUP_IMPLICIT);
9614 }
9616 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9617 permitted. If the conversion is valid, the converted expression is
9618 returned. Otherwise, NULL_TREE is returned, except in the case
9619 that TYPE is a class type; in that case, an error is issued. If
9620 C_CAST_P is true, then this direct-initialization is taking
9621 place as part of a static_cast being attempted as part of a C-style
9622 cast. */
9624 tree
9626 tree expr,
9628 tsubst_flags_t complain)
9629 {
9635 /* [dcl.init]
9637 If the destination type is a (possibly cv-qualified) class type:
9639 -- If the initialization is direct-initialization ...,
9640 constructors are considered. ... If no constructor applies, or
9641 the overload resolution is ambiguous, the initialization is
9642 ill-formed. */
9644 {
9650 }
9652 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9656 c_cast_p,
9660 else
9663 c_cast_p,
9664 complain);
9666 /* Free all the conversions we allocated. */
9670 }
9672 /* When initializing a reference that lasts longer than a full-expression,
9673 this special rule applies:
9675 [class.temporary]
9677 The temporary to which the reference is bound or the temporary
9678 that is the complete object to which the reference is bound
9679 persists for the lifetime of the reference.
9681 The temporaries created during the evaluation of the expression
9682 initializing the reference, except the temporary to which the
9683 reference is bound, are destroyed at the end of the
9684 full-expression in which they are created.
9686 In that case, we store the converted expression into a new
9687 VAR_DECL in a new scope.
9689 However, we want to be careful not to create temporaries when
9690 they are not required. For example, given:
9692 struct B {};
9693 struct D : public B {};
9694 D f();
9695 const B& b = f();
9697 there is no need to copy the return value from "f"; we can just
9698 extend its lifetime. Similarly, given:
9700 struct S {};
9701 struct T { operator S(); };
9702 T t;
9703 const S& s = t;
9705 we can extend the lifetime of the return value of the conversion
9706 operator.
9708 The next several functions are involved in this lifetime extension. */
9710 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9711 reference is being bound to a temporary. Create and return a new
9712 VAR_DECL with the indicated TYPE; this variable will store the value to
9713 which the reference is bound. */
9715 tree
9717 {
9718 tree var;
9720 /* Create the variable. */
9723 /* Register the variable. */
9726 {
9727 /* Namespace-scope or local static; give it a mangled name. */
9728 /* FIXME share comdat with decl? */
9729 tree name;
9738 }
9739 else
9740 /* Create a new cleanup level if necessary. */
9744 }
9746 /* EXPR is the initializer for a variable DECL of reference or
9747 std::initializer_list type. Create, push and return a new VAR_DECL
9748 for the initializer so that it will live as long as DECL. Any
9749 cleanup for the new variable is returned through CLEANUP, and the
9750 code to initialize the new variable is returned through INITP. */
9752 static tree
9755 {
9756 tree init;
9757 tree type;
9758 tree var;
9760 /* Create the temporary variable. */
9764 /* If the rvalue is the result of a function call it will be
9765 a TARGET_EXPR. If it is some other construct (such as a
9766 member access expression where the underlying object is
9767 itself the result of a function call), turn it into a
9768 TARGET_EXPR here. It is important that EXPR be a
9769 TARGET_EXPR below since otherwise the INIT_EXPR will
9770 attempt to make a bitwise copy of EXPR to initialize
9771 VAR. */
9777 {
9781 }
9783 /* Recursively extend temps in this initializer. */
9787 /* Any reference temp has a non-trivial initializer. */
9790 /* If the initializer is constant, put it in DECL_INITIAL so we get
9791 static initialization and use in constant expressions. */
9794 {
9796 {
9797 /* 5.19 says that a constant expression can include an
9798 lvalue-rvalue conversion applied to "a glvalue of literal type
9799 that refers to a non-volatile temporary object initialized
9800 with a constant expression". Rather than try to communicate
9801 that this VAR_DECL is a temporary, just mark it constexpr.
9803 Currently this is only useful for initializer_list temporaries,
9804 since reference vars can't appear in constant expressions. */
9808 }
9811 }
9812 else
9813 /* Create the INIT_EXPR that will initialize the temporary
9814 variable. */
9817 {
9822 else
9823 {
9827 }
9829 /* We must be careful to destroy the temporary only
9830 after its initialization has taken place. If the
9831 initialization throws an exception, then the
9832 destructor should not be run. We cannot simply
9833 transform INIT into something like:
9835 (INIT, ({ CLEANUP_STMT; }))
9837 because emit_local_var always treats the
9838 initializer as a full-expression. Thus, the
9839 destructor would run too early; it would run at the
9840 end of initializing the reference variable, rather
9841 than at the end of the block enclosing the
9842 reference variable.
9844 The solution is to pass back a cleanup expression
9845 which the caller is responsible for attaching to
9846 the statement tree. */
9847 }
9848 else
9849 {
9852 {
9855 tls_aggregates);
9856 else
9858 static_aggregates);
9859 }
9860 else
9861 /* Check whether the dtor is callable. */
9863 }
9864 /* Avoid -Wunused-variable warning (c++/38958). */
9871 }
9873 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9874 initializing a variable of that TYPE. */
9876 tree
9879 {
9887 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9893 {
9895 {
9904 else
9908 }
9910 }
9913 /* Perform the conversion. */
9916 /* We gave an error in build_user_type_conversion_1. */
9918 else
9921 /* Free all the conversions we allocated. */
9925 }
9927 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9928 which is bound either to a reference or a std::initializer_list. */
9930 static tree
9932 {
9937 {
9941 }
9944 /* Deal with binding to a subobject. */
9948 {
9956 }
9958 }
9960 /* INIT is part of the initializer for DECL. If there are any
9961 reference or initializer lists being initialized, extend their
9962 lifetime to match that of DECL. */
9964 tree
9966 {
9973 {
9974 /* The temporary array underlying a std::initializer_list
9975 is handled like a reference temporary. */
9980 {
9984 }
9985 }
9987 {
9993 }
9996 }
9998 /* Returns true iff an initializer for TYPE could contain temporaries that
9999 need to be extended because they are bound to references or
10000 std::initializer_list. */
10002 bool
10004 {
10009 {
10016 }
10018 }
10020 /* Returns true iff TYPE is some variant of std::initializer_list. */
10022 bool
10024 {
10025 /* Look through typedefs. */
10034 }
10036 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10037 will accept an argument list of a single std::initializer_list<T>. */
10039 bool
10041 {
10043 tree arg;
10055 /* There are more non-defaulted parms. */
10059 }