| blob | ce87be72c14f572748174a65d725b62e072771a5 |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987-2016 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) and
4 modified by Brendan Kehoe (brendan@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
23 /* High-level class interface. */
43 /* The various kinds of conversion. */
46 ck_identity,
47 ck_lvalue,
48 ck_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 }
3043 {
3044 /* 12.8/6 says, "A declaration of a constructor for a class X is
3045 ill-formed if its first parameter is of type (optionally cv-qualified)
3046 X and either there are no other parameters or else all other
3047 parameters have default arguments. A member function template is never
3048 instantiated to produce such a constructor signature."
3050 So if we're trying to copy an object of the containing class, don't
3051 consider a template constructor that has a first parameter type that
3052 is just a template parameter, as we would deduce a signature that we
3053 would then reject in the code below. */
3055 {
3060 {
3064 }
3065 }
3066 }
3073 {
3076 }
3080 {
3083 }
3088 args_without_in_chrg,
3089 nargs_without_in_chrg,
3094 {
3095 /* Don't repeat unification later if it already resulted in errors. */
3099 nargs_without_in_chrg,
3101 else
3104 }
3107 {
3110 ctype))
3111 {
3112 /* We're trying to produce a constructor with a prohibited signature,
3113 as discussed above; handle here any cases we didn't catch then,
3114 such as X(X<T>). */
3117 }
3118 }
3121 /* Aha, this is a conversion function. */
3124 else
3129 /* This situation can occur if a member template of a template
3130 class is specialized. Then, instantiate_template might return
3131 an instantiation of the specialization, in which case the
3132 DECL_TI_TEMPLATE field will point at the original
3133 specialization. For example:
3135 template <class T> struct S { template <class U> void f(U);
3136 template <> void f(int) {}; };
3137 S<double> sd;
3138 sd.f(3);
3140 Here, TMPL will be template <class U> S<double>::f(U).
3141 And, instantiate template will give us the specialization
3142 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3143 for this will point at template <class T> template <> S<T>::f(int),
3144 so that we can find the definition. For the purposes of
3145 overload resolution, however, we want the original TMPL. */
3147 else
3152 fail:
3155 }
3164 {
3165 return
3170 }
3172 /* Create an overload candidate for the conversion function template TMPL,
3173 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3174 pointer-to-function which will in turn be called with the argument list
3175 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3176 passed on to implicit_conversion. */
3180 tree obj,
3184 {
3185 return
3189 complain);
3190 }
3192 /* The CANDS are the set of candidates that were considered for
3193 overload resolution. Return the set of viable candidates, or CANDS
3194 if none are viable. If any of the candidates were viable, set
3195 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3196 considered viable only if it is strictly viable. */
3202 {
3208 /* Be strict inside templates, since build_over_call won't actually
3209 do the conversions to get pedwarns. */
3219 {
3223 {
3224 /* Be strict in the presence of a viable candidate. Also if
3225 there are template candidates, so that we get deduction errors
3226 for them instead of silently preferring a bad conversion. */
3229 {
3230 /* Put any spliced near matches back onto the main list so
3231 that we see them if there is no strict match. */
3237 }
3238 }
3241 {
3249 }
3250 else
3252 }
3255 }
3257 static bool
3259 {
3264 }
3266 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3267 words, it is about to become the "this" pointer for a member
3268 function call. Take the address of the object. */
3270 static tree
3272 {
3273 /* In a template, we are only concerned about the type of the
3274 expression, so we can take a shortcut. */
3279 }
3281 /* Returns true iff functions are equivalent. Equivalent functions are
3282 not '==' only if one is a function-local extern function or if
3283 both are extern "C". */
3287 {
3296 }
3298 /* Print information about a candidate being rejected due to INFO. */
3300 static void
3302 {
3307 {
3308 /* Conversion of implicit `this' argument failed. */
3310 /* A bad conversion for 'this' must be discarding cv-quals. */
3313 from);
3314 else
3318 }
3320 {
3325 tf_warning_or_error);
3326 }
3328 /* Conversion of conversion function return value failed. */
3331 else
3334 }
3336 /* Print information about a candidate with WANT parameters and we found
3337 HAVE. */
3339 static void
3341 {
3346 }
3348 /* Print information about one overload candidate CANDIDATE. MSGSTR
3349 is the text to print before the candidate itself.
3351 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3352 to have been run through gettext by the caller. This wart makes
3353 life simpler in print_z_candidates and for the translators. */
3355 static void
3358 {
3365 {
3376 else
3379 }
3386 else
3388 /* Give the user some information about why this candidate failed. */
3390 {
3394 {
3407 "cannot be converted to %qT with a qualification "
3413 "conversion function specialization to %qT is not an "
3418 /* We use template_unification_error_rejection if unification caused
3419 actual non-SFINAE errors, in which case we don't need to repeat
3420 them here. */
3422 {
3426 }
3427 /* Re-run template unification with diagnostics. */
3431 (make_tree_vec
3442 " a constructor taking a single argument of its own "
3446 {
3450 }
3454 /* This candidate didn't have any issues or we failed to
3455 handle a particular code. Either way... */
3457 }
3458 }
3459 }
3461 static void
3463 {
3470 /* Remove non-viable deleted candidates. */
3473 {
3478 else
3480 }
3481 /* ...if there are any non-deleted ones. */
3485 /* There may be duplicates in the set of candidates. We put off
3486 checking this condition as long as possible, since we have no way
3487 to eliminate duplicates from a set of functions in less than n^2
3488 time. Now we are about to emit an error message, so it is more
3489 permissible to go slowly. */
3491 {
3493 /* Skip builtin candidates and conversion functions. */
3498 {
3502 else
3504 }
3505 }
3509 }
3511 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3512 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3513 the result of the conversion function to convert it to the final
3514 desired type. Merge the two sequences into a single sequence,
3515 and return the merged sequence. */
3519 {
3525 /* Find the end of the second conversion sequence. */
3527 {
3528 /* The entire sequence is a user-conversion sequence. */
3532 }
3534 /* Replace the identity conversion with the user conversion
3535 sequence. */
3539 }
3541 /* Handle overload resolution for initializing an object of class type from
3542 an initializer list. First we look for a suitable constructor that
3543 takes a std::initializer_list; if we don't find one, we then look for a
3544 non-list constructor.
3546 Parameters are as for add_candidates, except that the arguments are in
3547 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3548 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3550 static void
3557 tsubst_flags_t complain)
3558 {
3563 /* We're looking for a ctor for list-initialization. */
3565 /* And we don't allow narrowing conversions. We also use this flag to
3566 avoid the copy constructor call for copy-list-initialization. */
3569 /* Always use the default constructor if the list is empty (DR 990). */
3572 ;
3573 /* If the class has a list ctor, try passing the list as a single
3574 argument first, but only consider list ctors. */
3576 {
3584 }
3588 /* We aren't looking for list-ctors anymore. */
3590 /* We allow more user-defined conversions within an init-list. */
3596 }
3598 /* Returns the best overload candidate to perform the requested
3599 conversion. This function is used for three the overloading situations
3600 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3601 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3602 per [dcl.init.ref], so we ignore temporary bindings. */
3606 tsubst_flags_t complain)
3607 {
3609 tree fromtype;
3623 /* We represent conversion within a hierarchy using RVALUE_CONV and
3624 BASE_CONV, as specified by [over.best.ics]; these become plain
3625 constructor calls, as specified in [dcl.init]. */
3630 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3631 creating a garbage BASELINK; constructors can't be inherited. */
3635 {
3640 {
3641 /* [class.conv.fct] A conversion function is never used to
3642 convert a (possibly cv-qualified) object to the (possibly
3643 cv-qualified) same object type (or a reference to it), to a
3644 (possibly cv-qualified) base class of that type (or a
3645 reference to it)... */
3646 }
3647 else
3649 }
3656 /* It's OK to bind a temporary for converting constructor arguments, but
3657 not in converting the return value of a conversion operator. */
3663 {
3668 /* We should never try to call the abstract or base constructor
3669 from here. */
3674 {
3675 /* List-initialization. */
3679 }
3680 else
3681 {
3686 }
3689 {
3692 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3693 set, then this is copy-initialization. In that case, "The
3694 result of the call is then used to direct-initialize the
3695 object that is the destination of the copy-initialization."
3696 [dcl.init]
3698 We represent this in the conversion sequence with an
3699 rvalue conversion, which means a constructor call. */
3702 cand->second_conv
3704 }
3705 }
3711 {
3715 /* If we are called to convert to a reference type, we are trying to
3716 find a direct binding, so don't even consider temporaries. If
3717 we don't find a direct binding, the caller will try again to
3718 look for a temporary binding. */
3729 {
3731 conversion *ics
3733 rettype,
3736 complain);
3738 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3739 copy-initialization. In that case, "The result of the
3740 call is then used to direct-initialize the object that is
3741 the destination of the copy-initialization." [dcl.init]
3743 We represent this in the conversion sequence with an
3744 rvalue conversion, which means a constructor call. But
3745 don't add a second rvalue conversion if there's already
3746 one there. Which there really shouldn't be, but it's
3747 harmless since we'd add it here anyway. */
3755 {
3759 }
3762 {
3763 /* 13.3.1.5: For direct-initialization, those explicit
3764 conversion functions that are not hidden within S and
3765 yield type T or a type that can be converted to type T
3766 with a qualification conversion (4.4) are also candidate
3767 functions. */
3768 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3769 I've raised this issue with the committee. --jason 9/2011 */
3772 }
3774 {
3776 cand->reason
3779 }
3782 {
3783 /* 13.3.3.1.2: If the user-defined conversion is specified by
3784 a specialization of a conversion function template, the
3785 second standard conversion sequence shall have exact match
3786 rank. */
3789 }
3790 }
3791 }
3795 {
3799 }
3803 {
3805 {
3809 }
3816 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3817 ambiguous conversion is no worse than another user-defined
3818 conversion. */
3821 }
3823 tree convtype;
3827 /* DR 5: [in the first step of copy-initialization]...if the function
3828 is a constructor, the call initializes a temporary of the
3829 cv-unqualified version of the destination type. */
3831 else
3833 /* Build the user conversion sequence. */
3834 conv = build_conv
3836 convtype,
3842 /* Remember that this was a list-initialization. */
3846 /* Combine it with the second conversion sequence. */
3851 }
3853 /* Wrapper for above. */
3855 tree
3857 tsubst_flags_t complain)
3858 {
3860 tree ret;
3866 {
3869 else
3870 {
3873 }
3874 }
3875 else
3880 }
3882 /* Subroutine of convert_nontype_argument.
3884 EXPR is an argument for a template non-type parameter of integral or
3885 enumeration type. Do any necessary conversions (that are permitted for
3886 non-type arguments) to convert it to the parameter type.
3888 If conversion is successful, returns the converted expression;
3889 otherwise, returns error_mark_node. */
3891 tree
3893 {
3896 tree t;
3904 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3911 /* for a non-type template-parameter of integral or
3912 enumeration type, integral promotions (4.5) and integral
3913 conversions (4.7) are applied. */
3914 /* It should be sufficient to check the outermost conversion step, since
3915 there are no qualification conversions to integer type. */
3918 {
3919 /* A conversion function is OK. If it isn't constexpr, we'll
3920 complain later that the argument isn't constant. */
3922 /* The lvalue-to-rvalue conversion is OK. */
3935 /* and fall through. */
3940 }
3944 else
3947 /* Free all the conversions we allocated. */
3951 }
3953 /* Do any initial processing on the arguments to a function call. */
3957 {
3959 tree arg;
3962 {
3966 {
3970 }
3973 }
3975 }
3977 /* Perform overload resolution on FN, which is called with the ARGS.
3979 Return the candidate function selected by overload resolution, or
3980 NULL if the event that overload resolution failed. In the case
3981 that overload resolution fails, *CANDIDATES will be the set of
3982 candidates considered, and ANY_VIABLE_P will be set to true or
3983 false to indicate whether or not any of the candidates were
3984 viable.
3986 The ARGS should already have gone through RESOLVE_ARGS before this
3987 function is called. */
3994 {
3996 tree explicit_targs;
4007 /* Check FN. */
4014 {
4018 }
4020 /* Add the various candidate functions. */
4025 LOOKUP_NORMAL,
4031 else
4036 }
4038 /* Print an error message about being unable to build a call to FN with
4039 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4040 be located; CANDIDATES is a possibly empty list of such
4041 functions. */
4043 static void
4046 {
4053 else
4058 }
4060 /* Return an expression for a call to FN (a namespace-scope function,
4061 or a static member function) with the ARGS. This may change
4062 ARGS. */
4064 tree
4066 tsubst_flags_t complain)
4067 {
4071 tree result;
4074 {
4078 }
4083 /* If this function was found without using argument dependent
4084 lookup, then we want to ignore any undeclared friend
4085 functions. */
4087 {
4092 {
4096 }
4097 }
4099 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4103 complain);
4106 {
4108 {
4109 // If there is a single (non-viable) function candidate,
4110 // let the error be diagnosed by cp_build_function_call_vec.
4115 // Otherwise, emit notes for non-viable candidates.
4119 }
4121 }
4122 else
4123 {
4125 /* If fn is template_id_expr, the call has explicit template arguments
4126 (e.g. func<int>(5)), communicate this info to build_over_call
4127 through flags so that later we can use it to decide whether to warn
4128 about peculiar null pointer conversion. */
4130 {
4131 /* If overload resolution selects a specialization of a
4132 function concept for non-dependent template arguments,
4133 the expression is true if the constraints are satisfied
4134 and false otherwise.
4136 NOTE: This is an extension of Concepts Lite TS that
4137 allows constraints to be used in expressions. */
4139 {
4145 }
4148 }
4151 }
4153 /* Free all the conversions we allocated. */
4157 }
4159 /* Build a call to a global operator new. FNNAME is the name of the
4160 operator (either "operator new" or "operator new[]") and ARGS are
4161 the arguments provided. This may change ARGS. *SIZE points to the
4162 total number of bytes required by the allocation, and is updated if
4163 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4164 be used. If this function determines that no cookie should be
4165 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4166 is not NULL_TREE, it is evaluated before calculating the final
4167 array size, and if it fails, the array size is replaced with
4168 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4169 is non-NULL, it will be set, upon return, to the allocation
4170 function called. */
4172 tree
4176 {
4178 tree fns;
4185 /* Set to (size_t)-1 if the size check fails. */
4187 {
4193 }
4199 /* Based on:
4201 [expr.new]
4203 If this lookup fails to find the name, or if the allocated type
4204 is not a class type, the allocation function's name is looked
4205 up in the global scope.
4207 we disregard block-scope declarations of "operator new". */
4210 /* Figure out what function is being called. */
4212 complain);
4214 /* If no suitable function could be found, issue an error message
4215 and give up. */
4217 {
4221 }
4223 /* If a cookie is required, add some extra space. Whether
4224 or not a cookie is required cannot be determined until
4225 after we know which function was called. */
4227 {
4229 tree arg_types;
4232 /* Skip the size_t parameter. */
4234 /* Check the remaining parameters (if any). */
4238 ptr_type_node))
4240 /* If we need a cookie, adjust the number of bytes allocated. */
4242 {
4243 /* Update the total size. */
4246 {
4247 /* Set to (size_t)-1 if the size check fails. */
4251 }
4252 /* Update the argument list to reflect the adjusted size. */
4254 }
4255 else
4257 }
4259 /* Tell our caller which function we decided to call. */
4263 /* Build the CALL_EXPR. */
4265 }
4267 /* Build a new call to operator(). This may change ARGS. */
4269 static tree
4271 {
4285 {
4287 /* It's no good looking for an overloaded operator() on a
4288 pointer-to-member-function. */
4289 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4291 }
4294 {
4298 }
4299 else
4303 {
4307 }
4309 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4313 {
4321 }
4326 {
4335 {
4342 add_template_conv_candidate
4346 else
4350 }
4351 }
4353 /* Be strict here because if we choose a bad conversion candidate, the
4354 errors we get won't mention the call context. */
4357 {
4359 {
4363 }
4365 }
4366 else
4367 {
4370 {
4372 {
4376 }
4378 }
4379 /* Since cand->fn will be a type, not a function, for a conversion
4380 function, we must be careful not to unconditionally look at
4381 DECL_NAME here. */
4385 else
4386 {
4388 complain);
4391 }
4392 }
4394 /* Free all the conversions we allocated. */
4398 }
4400 /* Wrapper for above. */
4402 tree
4404 {
4405 tree ret;
4410 }
4412 /* Called by op_error to prepare format strings suitable for the error
4413 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4414 and a suffix (controlled by NTYPES). */
4418 {
4428 else
4432 }
4434 static void
4437 {
4442 else
4446 {
4452 else
4464 else
4474 else
4485 else
4495 else
4500 else
4504 else
4509 }
4510 }
4512 /* Return the implicit conversion sequence that could be used to
4513 convert E1 to E2 in [expr.cond]. */
4517 {
4523 /* [expr.cond]
4525 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4526 implicitly converted (clause _conv_) to the type "lvalue reference to
4527 T2", subject to the constraint that in the conversion the
4528 reference must bind directly (_dcl.init.ref_) to an lvalue.
4530 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4531 implicitly converted to the type "rvalue reference to T2", subject to
4532 the constraint that the reference must bind directly. */
4534 {
4537 t1,
4538 e1,
4540 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4542 complain);
4545 }
4547 /* If E2 is a prvalue or if neither of the conversions above can be done
4548 and at least one of the operands has (possibly cv-qualified) class
4549 type: */
4553 /* [expr.cond]
4555 If E1 and E2 have class type, and the underlying class types are
4556 the same or one is a base class of the other: E1 can be converted
4557 to match E2 if the class of T2 is the same type as, or a base
4558 class of, the class of T1, and the cv-qualification of T2 is the
4559 same cv-qualification as, or a greater cv-qualification than, the
4560 cv-qualification of T1. If the conversion is applied, E1 is
4561 changed to an rvalue of type T2 that still refers to the original
4562 source class object (or the appropriate subobject thereof). */
4565 {
4567 {
4572 else
4575 }
4576 else
4578 }
4579 else
4580 /* [expr.cond]
4582 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4583 converted to the type that expression E2 would have if E2 were
4584 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4587 }
4589 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4590 arguments to the conditional expression. */
4592 static tree
4594 tsubst_flags_t complain)
4595 {
4596 tree arg2_type;
4597 tree arg3_type;
4606 /* As a G++ extension, the second argument to the conditional can be
4607 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4608 c'.) If the second operand is omitted, make sure it is
4609 calculated only once. */
4611 {
4616 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4619 else
4621 }
4623 /* If something has already gone wrong, just pass that fact up the
4624 tree. */
4634 {
4635 /* If arg1 is another cond_expr choosing between -1 and 0,
4636 then we can use its comparison. It may help to avoid
4637 additional comparison, produce more accurate diagnostics
4638 and enables folding. */
4648 /* force_rvalue can return error_mark on valid arguments. */
4660 {
4661 /* Rely on the error messages of the scalar version. */
4670 {
4678 }
4682 /* We could pass complain & tf_warning to unsafe_conversion_p,
4683 but the warnings (like Wsign-conversion) have already been
4684 given by the scalar build_conditional_expr_1. We still check
4685 unsafe_conversion_p to forbid truncating long long -> float. */
4687 {
4692 }
4694 {
4699 }
4709 }
4712 {
4718 {
4722 {
4728 }
4730 {
4736 }
4739 }
4740 }
4746 {
4749 "incompatible vector types in conditional expression: "
4753 }
4756 {
4759 }
4761 }
4763 /* [expr.cond]
4765 The first expression is implicitly converted to bool (clause
4766 _conv_). */
4768 LOOKUP_NORMAL);
4772 /* [expr.cond]
4774 If either the second or the third operand has type (possibly
4775 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4776 array-to-pointer (_conv.array_), and function-to-pointer
4777 (_conv.func_) standard conversions are performed on the second
4778 and third operands. */
4782 {
4783 /* Do the conversions. We don't these for `void' type arguments
4784 since it can't have any effect and since decay_conversion
4785 does not handle that case gracefully. */
4793 /* [expr.cond]
4795 One of the following shall hold:
4797 --The second or the third operand (but not both) is a
4798 throw-expression (_except.throw_); the result is of the
4799 type of the other and is an rvalue.
4801 --Both the second and the third operands have type void; the
4802 result is of type void and is an rvalue.
4804 We must avoid calling force_rvalue for expressions of type
4805 "void" because it will complain that their value is being
4806 used. */
4809 {
4811 {
4815 }
4818 }
4821 {
4823 {
4827 }
4830 }
4833 else
4834 {
4836 {
4839 "second operand to the conditional operator "
4840 "is of type %<void%>, but the third operand is "
4842 else
4844 "third operand to the conditional operator "
4845 "is of type %<void%>, but the second operand is "
4847 }
4849 }
4853 }
4854 /* [expr.cond]
4856 Otherwise, if the second and third operand have different types,
4857 and either has (possibly cv-qualified) class type, or if both are
4858 glvalues of the same value category and the same type except for
4859 cv-qualification, an attempt is made to convert each of those operands
4860 to the type of the other. */
4864 arg3_type)
4868 {
4873 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4879 /* [expr.cond]
4881 If both can be converted, or one can be converted but the
4882 conversion is ambiguous, the program is ill-formed. If
4883 neither can be converted, the operands are left unchanged and
4884 further checking is performed as described below. If exactly
4885 one conversion is possible, that conversion is applied to the
4886 chosen operand and the converted operand is used in place of
4887 the original operand for the remainder of this section. */
4892 {
4894 {
4901 else
4903 }
4905 }
4907 {
4911 /* Even if CONV2 is a valid conversion, the result of the
4912 conversion may be invalid. For example, if ARG3 has type
4913 "volatile X", and X does not have a copy constructor
4914 accepting a "volatile X&", then even if ARG2 can be
4915 converted to X, the conversion will fail. */
4919 }
4921 {
4928 }
4930 /* Free all the conversions we allocated. */
4936 /* If, after the conversion, both operands have class type,
4937 treat the cv-qualification of both operands as if it were the
4938 union of the cv-qualification of the operands.
4940 The standard is not clear about what to do in this
4941 circumstance. For example, if the first operand has type
4942 "const X" and the second operand has a user-defined
4943 conversion to "volatile X", what is the type of the second
4944 operand after this step? Making it be "const X" (matching
4945 the first operand) seems wrong, as that discards the
4946 qualification without actually performing a copy. Leaving it
4947 as "volatile X" seems wrong as that will result in the
4948 conditional expression failing altogether, even though,
4949 according to this step, the one operand could be converted to
4950 the type of the other. */
4958 }
4960 /* [expr.cond]
4962 If the second and third operands are glvalues of the same value
4963 category and have the same type, the result is of that type and
4964 value category. */
4968 {
4973 }
4975 /* [expr.cond]
4977 Otherwise, the result is an rvalue. If the second and third
4978 operand do not have the same type, and either has (possibly
4979 cv-qualified) class type, overload resolution is used to
4980 determine the conversions (if any) to be applied to the operands
4981 (_over.match.oper_, _over.built_). */
4985 {
4990 /* Rearrange the arguments so that add_builtin_candidate only has
4991 to know about two args. In build_builtin_candidate, the
4992 arguments are unscrambled. */
4997 COND_EXPR,
4998 NOP_EXPR,
5000 args,
5003 /* [expr.cond]
5005 If the overload resolution fails, the program is
5006 ill-formed. */
5009 {
5014 }
5017 {
5019 {
5022 }
5024 }
5026 /* [expr.cond]
5028 Otherwise, the conversions thus determined are applied, and
5029 the converted operands are used in place of the original
5030 operands for the remainder of this section. */
5039 }
5041 /* [expr.cond]
5043 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5044 and function-to-pointer (_conv.func_) standard conversions are
5045 performed on the second and third operands.
5047 We need to force the lvalue-to-rvalue conversion here for class types,
5048 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5049 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5050 regions. */
5063 /* [expr.cond]
5065 After those conversions, one of the following shall hold:
5067 --The second and third operands have the same type; the result is of
5068 that type. */
5071 /* [expr.cond]
5073 --The second and third operands have arithmetic or enumeration
5074 type; the usual arithmetic conversions are performed to bring
5075 them to a common type, and the result is of that type. */
5080 {
5081 /* In this case, there is always a common type. */
5083 arg3_type);
5086 "implicit conversion from %qT to %qT to "
5088 loc);
5092 {
5096 /* Two enumerators from the same enumeration can have different
5102 }
5109 {
5113 }
5117 }
5118 /* [expr.cond]
5120 --The second and third operands have pointer type, or one has
5121 pointer type and the other is a null pointer constant; pointer
5122 conversions (_conv.ptr_) and qualification conversions
5123 (_conv.qual_) are performed to bring them to their composite
5124 pointer type (_expr.rel_). The result is of the composite
5125 pointer type.
5127 --The second and third operands have pointer to member type, or
5128 one has pointer to member type and the other is a null pointer
5129 constant; pointer to member conversions (_conv.mem_) and
5130 qualification conversions (_conv.qual_) are performed to bring
5131 them to a common type, whose cv-qualification shall match the
5132 cv-qualification of either the second or the third operand.
5133 The result is of the common type. */
5141 {
5144 complain);
5149 }
5152 {
5157 }
5162 valid_operands:
5165 /* We can't use result_type below, as fold might have returned a
5166 throw_expr. */
5169 {
5170 /* Expand both sides into the same slot, hopefully the target of
5171 the ?: expression. We used to check for TARGET_EXPRs here,
5172 but now we sometimes wrap them in NOP_EXPRs so the test would
5173 fail. */
5176 /* If this expression is an rvalue, but might be mistaken for an
5177 lvalue, we must add a NON_LVALUE_EXPR. */
5179 }
5180 else
5184 }
5186 /* Wrapper for above. */
5188 tree
5190 tsubst_flags_t complain)
5191 {
5192 tree ret;
5197 }
5199 /* OPERAND is an operand to an expression. Perform necessary steps
5200 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5201 returned. */
5203 static tree
5205 {
5207 {
5210 /* Make sure the template type is instantiated now. */
5212 }
5215 }
5217 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5218 OVERLOAD) to the CANDIDATES, returning an updated list of
5219 CANDIDATES. The ARGS are the arguments provided to the call;
5220 if FIRST_ARG is non-null it is the implicit object argument,
5221 otherwise the first element of ARGS is used if needed. The
5222 EXPLICIT_TARGS are explicit template arguments provided.
5223 TEMPLATE_ONLY is true if only template functions should be
5224 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5225 add_function_candidate. */
5227 static void
5229 tree return_type,
5234 tsubst_flags_t complain)
5235 {
5236 tree ctype;
5240 unification_kind_t strict;
5241 tree fn;
5246 /* Precalculate special handling of constructors and conversion ops. */
5249 {
5253 /* We're doing return_type(x). */
5255 else
5256 /* We're doing x.operator return_type(). */
5258 /* [over.match.funcs] For conversion functions, the function
5259 is considered to be a member of the class of the implicit
5260 object argument for the purpose of defining the type of
5261 the implicit object parameter. */
5263 }
5264 else
5265 {
5267 {
5269 /* For list-initialization we consider explicit constructors
5270 and complain if one is chosen. */
5271 check_converting
5274 }
5275 else
5276 {
5279 }
5282 }
5286 else
5287 /* Delay creating the implicit this parameter until it is needed. */
5291 {
5292 tree fn_first_arg;
5302 /* Figure out which set of arguments to use. */
5304 {
5305 /* If this function is a non-static member and we didn't get an
5306 implicit object argument, move it out of args. */
5308 {
5310 tree arg;
5317 }
5321 }
5322 else
5323 {
5324 /* Otherwise, just use the list of arguments provided. */
5327 }
5331 fn,
5332 ctype,
5333 explicit_targs,
5334 fn_first_arg,
5335 fn_args,
5336 return_type,
5337 access_path,
5338 conversion_path,
5339 flags,
5340 strict,
5341 complain);
5344 fn,
5345 ctype,
5346 fn_first_arg,
5347 fn_args,
5348 access_path,
5349 conversion_path,
5350 flags,
5351 complain);
5352 }
5353 }
5355 static tree
5358 {
5361 tree fnname;
5379 {
5383 }
5384 else
5391 {
5396 /* Use build_op_new_call and build_op_delete_call instead. */
5400 /* Use build_op_call instead. */
5407 /* These are saved for the sake of warn_logical_operator. */
5417 /* These are saved for the sake of maybe_warn_bool_compare. */
5422 /* =, ->, [], () must be non-static member functions. */
5433 }
5439 /* Use build_conditional_expr instead. */
5455 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5458 /* Add namespace-scope operators to the list of functions to
5459 consider. */
5471 /* Add class-member operators to the candidate set. */
5473 {
5474 tree fns;
5478 {
5481 }
5489 }
5490 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5491 only non-member functions that have type T1 or reference to
5492 cv-qualified-opt T1 for the first argument, if the first argument
5493 has an enumeration type, or T2 or reference to cv-qualified-opt
5494 T2 for the second argument, if the second argument has an
5495 enumeration type. Filter out those that don't match. */
5497 {
5501 {
5511 {
5517 && (same_type_ignoring_top_level_qualifiers_p
5522 }
5524 /* No argument has an appropriate type, so remove this
5525 candidate function from the list. */
5527 {
5530 }
5531 }
5532 }
5538 {
5541 /* For these, the built-in candidates set is empty
5542 [over.match.oper]/3. We don't want non-strict matches
5543 because exact matches are always possible with built-in
5544 operators. The built-in candidate set for COMPONENT_REF
5545 would be empty too, but since there are no such built-in
5546 operators, we accept non-strict matches for them. */
5553 }
5557 {
5559 {
5562 /* Don't try anything fancy if we're not allowed to produce
5563 errors. */
5567 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5568 distinguish between prefix and postfix ++ and
5569 operator++() was used for both, so we allow this with
5570 -fpermissive. */
5571 else
5572 {
5578 }
5585 else
5591 /* The caller will deal with these. */
5601 {
5602 /* If one of the arguments of the operator represents
5603 an invalid use of member function pointer, try to report
5604 a meaningful error ... */
5609 else
5610 {
5611 /* ... Otherwise, report the more generic
5612 "no matching operator found" error */
5615 }
5616 }
5619 }
5620 }
5621 else
5622 {
5625 {
5627 {
5630 }
5632 }
5634 {
5640 else
5647 {
5651 /* This prevents build_new_function_call from discarding this
5652 function during instantiation of the enclosing template. */
5654 }
5655 }
5656 else
5657 {
5658 /* Give any warnings we noticed during overload resolution. */
5660 {
5664 }
5666 /* Check for comparison of different enum types. */
5668 {
5680 {
5684 }
5688 }
5690 /* We need to strip any leading REF_BIND so that bitfields
5691 don't cause errors. This should not remove any important
5692 conversions, because builtins don't apply to class
5693 objects directly. */
5700 {
5704 else
5707 /* We need to call warn_logical_operator before
5708 converting arg2 to a boolean_type, but after
5709 decaying an enumerator to its value. */
5716 }
5718 {
5723 }
5725 }
5726 }
5728 user_defined_result_ready:
5730 /* Free all the conversions we allocated. */
5736 builtin:
5738 {
5753 /* Fall through. */
5766 /* Fall through. */
5799 complain),
5802 /* The caller will deal with these. */
5810 }
5812 }
5814 /* Wrapper for above. */
5816 tree
5820 {
5821 tree ret;
5827 }
5829 /* Returns true if FN has two parameters, of which the second has type
5830 size_t. */
5832 static bool
5834 {
5839 }
5841 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5842 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5844 bool
5846 {
5847 /* A template instance is never a usual deallocation function,
5848 regardless of its signature. */
5853 /* If a class T has a member deallocation function named operator delete
5854 with exactly one parameter, then that function is a usual
5855 (non-placement) deallocation function. If class T does not declare
5856 such an operator delete but does declare a member deallocation
5857 function named operator delete with exactly two parameters, the second
5858 of which has type std::size_t (18.2), then this function is a usual
5859 deallocation function. */
5866 }
5868 /* Build a call to operator delete. This has to be handled very specially,
5869 because the restrictions on what signatures match are different from all
5870 other call instances. For a normal delete, only a delete taking (void *)
5871 or (void *, size_t) is accepted. For a placement delete, only an exact
5872 match with the placement new is accepted.
5874 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5875 ADDR is the pointer to be deleted.
5876 SIZE is the size of the memory block to be deleted.
5877 GLOBAL_P is true if the delete-expression should not consider
5878 class-specific delete operators.
5879 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5881 If this call to "operator delete" is being generated as part to
5882 deallocate memory allocated via a new-expression (as per [expr.new]
5883 which requires that if the initialization throws an exception then
5884 we call a deallocation function), then ALLOC_FN is the allocation
5885 function. */
5887 tree
5891 {
5905 /* In [class.free]
5907 If the result of the lookup is ambiguous or inaccessible, or if
5908 the lookup selects a placement deallocation function, the
5909 program is ill-formed.
5911 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5912 {
5916 }
5917 else
5923 /* Strip const and volatile from addr. */
5927 {
5928 /* "A declaration of a placement deallocation function matches the
5929 declaration of a placement allocation function if it has the same
5930 number of parameters and, after parameter transformations (8.3.5),
5931 all parameter types except the first are identical."
5933 So we build up the function type we want and ask instantiate_type
5934 to get it for us. */
5946 /* "If the lookup finds the two-parameter form of a usual deallocation
5947 function (3.7.4.2) and that function, considered as a placement
5948 deallocation function, would have been selected as a match for the
5949 allocation function, the program is ill-formed." */
5951 {
5959 /* But if the class has an operator delete (void *), then that is
5960 the usual deallocation function, so we shouldn't complain
5961 about using the operator delete (void *, size_t). */
5965 {
5970 }
5971 /* Before C++14 a two-parameter global deallocation function is
5972 always a placement deallocation function, but warn if
5973 -Wc++14-compat. */
5975 {
5980 }
5983 {
5985 {
5986 /* Only mention C++14 for namespace-scope delete. */
5989 else
5991 "%qD is a usual (non-placement) deallocation "
5993 }
5994 }
5995 else
5997 ok:;
5998 }
5999 }
6000 else
6001 /* "Any non-placement deallocation function matches a non-placement
6002 allocation function. If the lookup finds a single matching
6003 deallocation function, that function will be called; otherwise, no
6004 deallocation function will be called." */
6007 {
6010 {
6012 /* "If a class T has a member deallocation function named
6013 operator delete with exactly one parameter, then that
6014 function is a usual (non-placement) deallocation
6015 function. If class T does not declare such an operator
6016 delete but does declare a member deallocation function named
6017 operator delete with exactly two parameters, the second of
6018 which has type std::size_t (18.2), then this function is a
6019 usual deallocation function."
6021 So in a class (void*) beats (void*, size_t). */
6023 {
6026 }
6027 /* At global scope (in C++14 and above) the rules are different:
6029 If deallocation function lookup finds both a usual
6030 deallocation function with only a pointer parameter and a
6031 usual deallocation function with both a pointer parameter
6032 and a size parameter, the function to be called is selected
6033 as follows:
6035 * If the type is complete and if, for the second alternative
6036 (delete array) only, the operand is a pointer to a class
6037 type with a non-trivial destructor or a (possibly
6038 multi-dimensional) array thereof, the function with two
6039 parameters is selected.
6041 * Otherwise, it is unspecified which of the two deallocation
6042 functions is selected. */
6043 else
6044 {
6048 /* We need a cookie to determine the array size. */
6053 }
6054 }
6055 }
6057 /* If we have a matching function, call it. */
6059 {
6062 /* If the FN is a member function, make sure that it is
6063 accessible. */
6066 complain);
6068 /* Core issue 901: It's ok to new a type with deleted delete. */
6073 {
6074 /* The placement args might not be suitable for overload
6075 resolution at this point, so build the call directly. */
6085 }
6086 else
6087 {
6088 tree ret;
6096 }
6097 }
6099 /* [expr.new]
6101 If no unambiguous matching deallocation function can be found,
6102 propagating the exception does not cause the object's memory to
6103 be freed. */
6105 {
6109 alloc_fn);
6111 }
6117 }
6119 /* If the current scope isn't allowed to access DECL along
6120 BASETYPE_PATH, give an error. The most derived class in
6121 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6122 the declaration to use in the error diagnostic. */
6124 bool
6126 tsubst_flags_t complain)
6127 {
6131 {
6133 {
6135 {
6139 }
6141 {
6145 }
6146 else
6147 {
6150 }
6151 }
6153 }
6156 }
6158 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6159 bitwise or of LOOKUP_* values. If any errors are warnings are
6160 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6161 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6162 to NULL. */
6164 static tree
6167 {
6180 else
6183 }
6185 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6186 EXPR is implicitly converted to type TOTYPE.
6187 FN and ARGNUM are used for diagnostics. */
6189 static void
6191 {
6192 /* Issue warnings about peculiar, but valid, uses of NULL. */
6195 {
6196 source_location loc =
6203 else
6206 }
6208 /* Issue warnings if "false" is converted to a NULL pointer */
6211 {
6214 "converting %<false%> to pointer type for argument %P "
6216 else
6219 }
6220 }
6222 /* We gave a diagnostic during a conversion. If this was in the second
6223 standard conversion sequence of a user-defined conversion sequence, say
6224 which user-defined conversion. */
6226 static void
6228 {
6232 {
6236 }
6237 }
6239 /* Perform the conversions in CONVS on the expression EXPR. FN and
6240 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6241 indicates the `this' argument of a method. INNER is nonzero when
6242 being called to continue a conversion chain. It is negative when a
6243 reference binding will be applied, positive otherwise. If
6244 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6245 conversions will be emitted if appropriate. If C_CAST_P is true,
6246 this conversion is coming from a C-style cast; in that case,
6247 conversions to inaccessible bases are permitted. */
6249 static tree
6253 {
6255 diagnostic_t diag_kind;
6271 {
6275 /* Give a helpful error if this is bad because of excess braces. */
6280 {
6286 }
6288 /* Give a helpful error if this is bad because a conversion to bool
6289 from std::nullptr_t requires direct-initialization. */
6297 {
6299 {
6302 totype);
6308 complain);
6312 complain);
6313 else
6319 }
6321 {
6325 complain);
6327 }
6332 complain);
6335 }
6344 }
6350 {
6352 {
6357 /* When converting from an init list we consider explicit
6358 constructors, but actually trying to call one is an error. */
6360 /* Unless this is for direct-list-initialization. */
6362 /* And in C++98 a default constructor can't be explicit. */
6364 {
6370 {
6376 }
6377 else
6380 }
6382 /* If we're initializing from {}, it's value-initialization. */
6386 {
6391 {
6394 }
6396 }
6400 /* Set user_conv_p on the argument conversions, so rvalue/base
6401 handling knows not to allow any more UDCs. */
6407 /* If this is a constructor or a function returning an aggr type,
6408 we need to build up a TARGET_EXPR. */
6410 {
6413 /* Remember that this was list-initialization. */
6416 }
6419 }
6422 {
6428 else
6430 }
6435 /* Convert a constant to its underlying value, unless we are
6436 about to bind it to a reference, in which case we need to
6437 leave it as an lvalue. */
6439 {
6442 /* If __null has been converted to an integer type, we do not
6443 want to warn about uses of EXPR as an integer, rather than
6444 as a pointer. */
6446 }
6449 /* We leave bad_p off ck_ambig because overload resolution considers
6450 it valid, it just fails when we try to perform it. So we need to
6451 check complain here, too. */
6453 {
6454 /* Call build_user_type_conversion again for the error. */
6456 complain);
6460 }
6464 {
6465 /* Conversion to std::initializer_list<T>. */
6473 /* Convert all the elements. */
6475 {
6486 }
6487 /* Build up the array. */
6488 elttype = cp_build_qualified_type
6492 /* Take the address explicitly rather than via decay_conversion
6493 to avoid the error about taking the address of a temporary. */
6499 /* Build up the initializer_list object. */
6507 }
6511 {
6520 }
6523 complain);
6530 };
6535 c_cast_p,
6536 complain);
6541 {
6545 {
6547 {
6552 }
6554 }
6558 /* Else fall through. */
6561 {
6562 /* We are going to bind a reference directly to a base-class
6563 subobject of EXPR. */
6564 /* Build an expression for `*((base*) &expr)'. */
6568 }
6570 /* Copy-initialization where the cv-unqualified version of the source
6571 type is the same class as, or a derived class of, the class of the
6572 destination [is treated as direct-initialization]. [dcl.init] */
6575 /* This conversion is being done in the context of a user-defined
6576 conversion (i.e. the second step of copy-initialization), so
6577 don't allow any more. */
6579 else
6585 /* Copy-list-initialization doesn't actually involve a copy. */
6589 {
6594 }
6599 {
6603 {
6616 else
6623 }
6625 /* If necessary, create a temporary.
6627 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6628 that need temporaries, even when their types are reference
6629 compatible with the type of reference being bound, so the
6630 upcoming call to cp_build_addr_expr doesn't fail. */
6634 {
6635 /* Otherwise, a temporary of type "cv1 T1" is created and
6636 initialized from the initializer expression using the rules
6637 for a non-reference copy-initialization (8.5). */
6646 {
6647 /* If the reference is volatile or non-const, we
6648 cannot create a temporary. */
6655 else
6659 }
6660 /* If the source is a packed field, and we must use a copy
6661 constructor, then building the target expr will require
6662 binding the field to the reference parameter to the
6663 copy constructor, and we'll end up with an infinite
6664 loop. If we can use a bitwise copy, then we'll be
6665 OK. */
6669 {
6673 }
6675 {
6678 }
6680 }
6682 /* Take the address of the thing to which we will bind the
6683 reference. */
6688 /* Convert it to a pointer to the type referred to by the
6689 reference. This will adjust the pointer if a derived to
6690 base conversion is being performed. */
6693 /* Convert the pointer to the desired reference type. */
6695 }
6701 /* ??? Should the address of a transaction-safe pointer point to the TM
6702 clone, and this conversion look up the primary function? */
6706 /* Warn about deprecated conversion if appropriate. */
6722 }
6730 else
6734 }
6736 /* ARG is being passed to a varargs function. Perform any conversions
6737 required. Return the converted value. */
6739 tree
6741 {
6742 tree arg_type;
6745 /* [expr.call]
6747 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6748 standard conversions are performed. */
6751 /* [expr.call]
6753 If the argument has integral or enumeration type that is subject
6754 to the integral promotions (_conv.prom_), or a floating point
6755 type that is subject to the floating point promotion
6756 (_conv.fpprom_), the value of the argument is converted to the
6757 promoted type before the call. */
6762 {
6766 "implicit conversion from %qT to %qT when passing "
6770 }
6774 {
6776 {
6778 complain);
6788 }
6789 else
6791 }
6797 /* In a template (or ill-formed code), we can have an incomplete type
6798 even after require_complete_type_sfinae, in which case we don't know
6799 whether it has trivial copy or not. */
6801 {
6802 /* Build up a real lvalue-to-rvalue conversion in case the
6803 copy constructor is trivial but not callable. */
6807 /* [expr.call] 5.2.2/7:
6808 Passing a potentially-evaluated argument of class type (Clause 9)
6809 with a non-trivial copy constructor or a non-trivial destructor
6810 with no corresponding parameter is conditionally-supported, with
6811 implementation-defined semantics.
6813 We support it as pass-by-invisible-reference, just like a normal
6814 value parameter.
6816 If the call appears in the context of a sizeof expression,
6817 it is not potentially-evaluated. */
6821 {
6824 "passing objects of non-trivially-copyable "
6826 arg_type);
6828 }
6829 }
6832 }
6834 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6836 tree
6838 {
6840 {
6844 }
6854 {
6857 }
6861 {
6862 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6863 it as pass by invisible reference. */
6865 "receiving objects of non-trivially-copyable type %q#T "
6871 }
6874 }
6876 /* TYPE has been given to va_arg. Apply the default conversions which
6877 would have happened when passed via ellipsis. Return the promoted
6878 type, or the passed type if there is no change. */
6880 tree
6882 {
6883 tree promote;
6885 /* Perform the array-to-pointer and function-to-pointer
6886 conversions. */
6894 }
6896 /* ARG is a default argument expression being passed to a parameter of
6897 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6898 zero-based argument number. Do any required conversions. Return
6899 the converted value. */
6902 void
6906 void
6910 tree
6912 tsubst_flags_t complain)
6913 {
6915 tree t;
6917 /* See through clones. */
6920 /* Detect recursion. */
6923 {
6927 }
6929 /* If the ARG is an unparsed default argument expression, the
6930 conversion cannot be performed. */
6932 {
6937 }
6944 /* Due to:
6946 [dcl.fct.default]
6948 The names in the expression are bound, and the semantic
6949 constraints are checked, at the point where the default
6950 expressions appears.
6952 we must not perform access checks here. */
6954 /* We must make a copy of ARG, in case subsequent processing
6955 alters any part of it. */
6959 complain);
6966 }
6968 /* Returns the type which will really be used for passing an argument of
6969 type TYPE. */
6971 tree
6973 {
6974 /* Pass classes with copy ctors by invisible reference. */
6976 {
6978 /* There are no other pointers to this temporary. */
6980 }
6988 }
6990 /* Actually perform the appropriate conversion. */
6992 tree
6994 {
6995 tree bitfield_type;
6997 /* If VAL is a bitfield, then -- since it has already been converted
6998 to TYPE -- it cannot have a precision greater than TYPE.
7000 If it has a smaller precision, we must widen it here. For
7001 example, passing "int f:3;" to a function expecting an "int" will
7002 not result in any conversion before this point.
7004 If the precision is the same we must not risk widening. For
7005 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7006 often have type "int", even though the C++ type for the field is
7007 "long long". If the value is being passed to a function
7008 expecting an "int", then no conversions will be required. But,
7009 if we call convert_bitfield_to_declared_type, the bitfield will
7010 be converted to "long long". */
7017 ;
7018 /* Pass classes with copy ctors by invisible reference. */
7028 {
7037 }
7039 }
7041 /* Returns true iff FN is a function with magic varargs, i.e. ones for
7042 which no conversions at all should be done. This is true for some
7043 builtins which don't act like normal functions. */
7045 bool
7047 {
7053 {
7063 }
7066 }
7068 /* Returns the decl of the dispatcher function if FN is a function version. */
7070 tree
7072 {
7082 {
7086 }
7091 }
7093 /* fn is a function version dispatcher that is marked used. Mark all the
7094 semantically identical function versions it will dispatch as used. */
7096 void
7098 {
7115 /* All semantically identical versions are chained. Traverse and mark each
7116 one of them as used. */
7119 {
7122 }
7123 }
7125 /* Build a call to "the copy constructor" for the type of A, even if it
7126 wouldn't be selected by normal overload resolution. Used for
7127 diagnostics. */
7129 static tree
7131 {
7142 }
7144 /* Return true iff T refers to a base field. */
7146 static bool
7148 {
7157 }
7159 /* We can't elide a copy from a function returning by value to a base
7160 subobject, as the callee might clobber tail padding. Return true iff this
7161 could be that case. */
7163 static bool
7165 {
7173 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7178 }
7180 /* Subroutine of the various build_*_call functions. Overload resolution
7181 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7182 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7183 bitmask of various LOOKUP_* flags which apply to the call itself. */
7185 static tree
7187 {
7195 tree val;
7204 /* In a template, there is no need to perform all of the work that
7205 is normally done. We are only interested in the type of the call
7206 expression, i.e., the return type of the function. Any semantic
7207 errors will be deferred until the template is instantiated. */
7209 {
7211 tree return_type;
7219 else
7220 {
7223 tree arg;
7231 }
7241 }
7243 /* Give any warnings we noticed during overload resolution. */
7245 {
7249 }
7251 /* Make =delete work with SFINAE. */
7256 {
7257 tree access_fn;
7258 /* If FN is a template function, two cases must be considered.
7259 For example:
7261 struct A {
7262 protected:
7263 template <class T> void f();
7264 };
7265 template <class T> struct B {
7266 protected:
7267 void g();
7268 };
7269 struct C : A, B<int> {
7270 using A::f; // #1
7271 using B<int>::g; // #2
7272 };
7274 In case #1 where `A::f' is a member template, DECL_ACCESS is
7275 recorded in the primary template but not in its specialization.
7276 We check access of FN using its primary template.
7278 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7279 because it is a member of class template B, DECL_ACCESS is
7280 recorded in the specialization `B<int>::g'. We cannot use its
7281 primary template because `B<T>::g' and `B<int>::g' may have
7282 different access. */
7286 else
7291 }
7293 /* If we're checking for implicit delete, don't bother with argument
7294 conversions. */
7296 {
7298 {
7302 }
7306 /* Reject bad conversions now. */
7308 /* else continue to get conversion error. */
7309 }
7311 /* N3276 magic doesn't apply to nested calls. */
7315 /* Find maximum size of vector to hold converted arguments. */
7322 /* The implicit parameters to a constructor are not considered by overload
7323 resolution, and must be of the proper type. */
7325 {
7326 tree object_arg;
7328 {
7331 }
7332 else
7333 {
7336 }
7339 /* We should never try to call the abstract constructor. */
7343 {
7347 }
7348 }
7349 /* Bypass access control for 'this' parameter. */
7351 {
7354 ? first_arg
7357 tree converted_arg;
7358 tree base_binfo;
7361 {
7363 {
7368 }
7369 else
7371 }
7373 /* See if the function member or the whole class type is declared
7374 final and the call can be devirtualized. */
7379 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7380 X is called for an object that is not of type X, or of a type
7381 derived from X, the behavior is undefined.
7383 So we can assume that anything passed as 'this' is non-null, and
7384 optimize accordingly. */
7386 /* Convert to the base in which the function was declared. */
7389 arg,
7392 /* Check that the base class is accessible. */
7395 {
7400 else
7402 }
7403 /* If fn was found by a using declaration, the conversion path
7404 will be to the derived class, not the base declaring fn. We
7405 must convert from derived to base. */
7416 else
7420 }
7425 {
7432 /* If the argument is NULL and used to (implicitly) instantiate a
7433 template function (and bind one of the template arguments to
7434 the type of 'long int'), we don't want to warn about passing NULL
7435 to non-pointer argument.
7436 For example, if we have this template function:
7438 template<typename T> void func(T x) {}
7440 we want to warn (when -Wconversion is enabled) in this case:
7442 void foo() {
7443 func<int>(NULL);
7444 }
7446 but not in this case:
7448 void foo() {
7449 func(NULL);
7450 }
7451 */
7458 /* Warn about initializer_list deduction that isn't currently in the
7459 working draft. */
7461 && flag_deduce_init_list
7465 {
7478 {
7486 }
7487 }
7489 conversion_warning
7490 ? complain
7497 else
7499 }
7501 /* Default arguments */
7503 {
7509 complain);
7510 }
7512 /* Ellipsis */
7514 {
7517 /* Do no conversions for magic varargs. */
7522 {
7523 /* Avoid infinite recursion trying to call A(...). */
7525 /* Try to call the actual copy constructor for a good error. */
7528 }
7529 else
7532 }
7537 /* Avoid to do argument-transformation, if warnings for format, and for
7538 nonnull are disabled. Just in case that at least one of them is active
7539 the check_function_arguments function might warn about something. */
7542 {
7549 }
7551 /* Avoid actually calling copy constructors and copy assignment operators,
7552 if possible. */
7559 /* It's unsafe to elide the constructor when handling
7560 a noexcept-expression, it may evaluate to the wrong
7561 value (c++/53025). */
7563 {
7564 tree targ;
7566 tree fa;
7569 /* Pull out the real argument, disregarding const-correctness. */
7575 {
7580 }
7581 else
7586 else
7589 /* [class.copy]: the copy constructor is implicitly defined even if
7590 the implementation elided its use. */
7592 {
7596 }
7598 /* If we're creating a temp and we already have one, don't create a
7599 new one. If we're not creating a temp but we get one, use
7600 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7601 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7602 temp or an INIT_EXPR otherwise. */
7605 {
7610 }
7614 {
7616 complain));
7620 }
7621 }
7625 {
7626 tree to = stabilize_reference
7633 {
7634 /* Avoid copying empty classes. */
7639 }
7641 {
7644 }
7645 else
7646 {
7647 /* We must only copy the non-tail padding parts. */
7655 build_index_type
7664 }
7667 }
7672 /* FIXME handle trivial default constructor, too. */
7674 /* For calls to a multi-versioned function, overload resolution
7675 returns the function with the highest target priority, that is,
7676 the version that will checked for dispatching first. If this
7677 version is inlinable, a direct call to this version can be made
7678 otherwise the call should go through the dispatcher. */
7683 {
7689 }
7696 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7697 virtual functions can't be constexpr. */
7699 {
7700 tree t;
7707 complain);
7713 else
7716 }
7717 else
7718 {
7722 }
7729 }
7731 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7732 This function performs no overload resolution, conversion, or other
7733 high-level operations. */
7735 tree
7737 tsubst_flags_t complain)
7738 {
7739 tree fndecl;
7741 /* Remember roughly where this call is. */
7748 /* Check that arguments to builtin functions match the expectations. */
7752 {
7755 /* We need to take care that values to BUILT_IN_NORMAL
7756 are reduced. */
7762 }
7764 /* If it is a built-in array notation function, then the return type of
7765 the function is the element type of the array passed in as array
7766 notation (i.e. the first parameter of the function). */
7768 {
7777 {
7779 {
7782 }
7783 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7784 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7785 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7786 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7787 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7788 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7789 The pre-defined return-type is the correct one. */
7793 }
7794 }
7799 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7800 function call is either the operand of a decltype-specifier or the
7801 right operand of a comma operator that is the operand of a
7802 decltype-specifier, a temporary object is not introduced for the
7803 prvalue. The type of the prvalue may be incomplete. */
7805 {
7812 }
7814 }
7818 /* Make an expression which yields the address of the Java interface
7819 method FN. This is achieved by generating a call to libjava's
7820 _Jv_LookupInterfaceMethodIdx(). */
7822 static tree
7824 {
7830 {
7834 java_iface_lookup_fn
7837 }
7839 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7840 This is the first entry in the vtable. */
7842 tf_warning_or_error),
7843 integer_zero_node);
7845 /* Get the java.lang.Class pointer for the interface being called. */
7850 {
7852 iface);
7854 }
7858 /* Determine the itable index of FN. */
7861 {
7866 i++;
7867 }
7872 java_iface_lookup_fn);
7875 }
7877 /* Returns the value to use for the in-charge parameter when making a
7878 call to a function with the indicated NAME.
7880 FIXME:Can't we find a neater way to do this mapping? */
7882 tree
7884 {
7895 /* This function should only be called with one of the names listed
7896 above. */
7899 }
7901 /* Build a call to a constructor, destructor, or an assignment
7902 operator for INSTANCE, an expression with class type. NAME
7903 indicates the special member function to call; *ARGS are the
7904 arguments. ARGS may be NULL. This may change ARGS. BINFO
7905 indicates the base of INSTANCE that is to be passed as the `this'
7906 parameter to the member function called.
7908 FLAGS are the LOOKUP_* flags to use when processing the call.
7910 If NAME indicates a complete object constructor, INSTANCE may be
7911 NULL_TREE. In this case, the caller will call build_cplus_new to
7912 store the newly constructed object into a VAR_DECL. */
7914 tree
7917 {
7918 tree fns;
7919 /* The type of the subobject to be constructed or destroyed. */
7920 tree class_type;
7922 tree ret;
7931 {
7932 /* Resolve the name. */
7937 }
7943 /* Handle the special case where INSTANCE is NULL_TREE. */
7946 else
7947 {
7953 /* Convert to the base class, if necessary. */
7956 {
7958 /* For constructors and destructors, either the base is
7959 non-virtual, or it is virtual but we are doing the
7960 conversion from a constructor or destructor for the
7961 complete object. In either case, we can convert
7962 statically. */
7964 else
7965 /* However, for assignment operators, we must convert
7966 dynamically if the base is virtual. */
7969 }
7970 }
7976 /* When making a call to a constructor or destructor for a subobject
7977 that uses virtual base classes, pass down a pointer to a VTT for
7978 the subobject. */
7982 {
7983 tree vtt;
7984 tree sub_vtt;
7986 /* If the current function is a complete object constructor
7987 or destructor, then we fetch the VTT directly.
7988 Otherwise, we look it up using the VTT we were given. */
7996 current_vtt_parm,
7997 vtt);
8000 else
8004 {
8007 }
8010 }
8015 complain);
8029 }
8031 /* Return the NAME, as a C string. The NAME indicates a function that
8032 is a member of TYPE. *FREE_P is set to true if the caller must
8033 free the memory returned.
8035 Rather than go through all of this, we should simply set the names
8036 of constructors and destructors appropriately, and dispense with
8037 ctor_identifier, dtor_identifier, etc. */
8041 {
8044 /* Assume that we will not allocate memory. */
8046 /* Constructors and destructors are special. */
8048 {
8049 pretty_name
8051 /* For a destructor, add the '~'. */
8055 {
8057 /* Remember that we need to free the memory allocated. */
8059 }
8060 }
8062 {
8065 TFF_PLAIN_IDENTIFIER),
8066 NULL);
8067 /* Remember that we need to free the memory allocated. */
8069 }
8070 else
8074 }
8076 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8077 be set, upon return, to the function called. ARGS may be NULL.
8078 This may change ARGS. */
8080 static tree
8084 {
8089 tree optype;
8091 tree name;
8094 tree call;
8095 tree fn;
8098 tree orig_instance;
8099 tree orig_fns;
8105 /* We don't know what function we're going to call, yet. */
8114 {
8118 }
8123 /* Dismantle the baselink to collect all the information we need. */
8131 {
8135 }
8146 {
8151 }
8154 /* Under DR 147 A::A() is an invalid constructor call,
8155 not a functional cast. */
8157 {
8167 complain);
8169 }
8171 /* Figure out whether to skip the first argument for the error
8172 message we will display to users if an error occurs. We don't
8173 want to display any compiler-generated arguments. The "this"
8174 pointer hasn't been added yet. However, we must remove the VTT
8175 pointer if this is a call to a base-class constructor or
8176 destructor. */
8179 {
8180 /* Callers should explicitly indicate whether they want to construct
8181 the complete object or just the part without virtual bases. */
8183 /* Similarly for destructors. */
8185 /* Remove the VTT pointer, if present. */
8189 }
8191 /* Process the argument list. */
8193 {
8197 }
8199 /* Consider the object argument to be used even if we end up selecting a
8200 static member function. */
8203 /* It's OK to call destructors and constructors on cv-qualified objects.
8204 Therefore, convert the INSTANCE to the unqualified type, if
8205 necessary. */
8208 {
8210 {
8214 }
8215 }
8219 /* For the overload resolution we need to find the actual `this`
8220 that would be captured if the call turns out to be to a
8221 non-static member function. Do not actually capture it at this
8222 point. */
8224 /* Constructors don't use the enclosing 'this'. */
8226 else
8229 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8232 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8233 initializer, not T({ }). */
8236 {
8243 /* If the initializer list has no elements and T is a class type with
8244 a default constructor, the object is value-initialized. Handle
8245 this here so we don't need to handle it wherever we use
8246 build_special_member_call. */
8249 /* For a user-provided default constructor, use the normal
8250 mechanisms so that protected access works. */
8255 /* If BASETYPE is an aggregate, we need to do aggregate
8256 initialization. */
8258 {
8261 }
8264 {
8270 }
8272 /* Otherwise go ahead with overload resolution. */
8277 }
8278 else
8279 {
8283 }
8288 {
8290 {
8297 else
8298 {
8301 tree arglist;
8312 }
8314 }
8316 }
8317 else
8318 {
8321 {
8324 tree arglist;
8327 {
8335 else
8341 }
8343 }
8344 else
8345 {
8353 {
8354 /* This is not an error, it is runtime undefined
8355 behavior. */
8364 fn);
8365 }
8370 {
8375 {
8376 /* We captured 'this' in the current lambda now that
8377 we know we really need it. */
8379 }
8380 else
8381 {
8384 fn);
8386 }
8387 }
8390 {
8391 /* Optimize away vtable lookup if we know that this
8392 function can't be overridden. We need to check if
8393 the context and the type where we found fn are the same,
8394 actually FN might be defined in a different class
8395 type because of a using-declaration. In this case, we
8396 do not want to perform a non-virtual call. */
8398 && same_type_ignoring_top_level_qualifiers_p
8404 /* Now we know what function is being called. */
8407 /* Build the actual CALL_EXPR. */
8409 /* In an expression of the form `a->f()' where `f' turns
8410 out to be a static member function, `a' is
8411 none-the-less evaluated. */
8420 /* An explicit call of the form "x->~X()" has type
8421 "void". However, on platforms where destructors
8422 return "this" (i.e., those where
8423 targetm.cxx.cdtor_returns_this is true), such calls
8424 will appear to have a return value of pointer type
8425 to the low-level call machinery. We do not want to
8426 change the low-level machinery, since we want to be
8427 able to optimize "delete f()" on such platforms as
8428 "operator delete(~X(f()))" (rather than generating
8429 "t = f(), ~X(t), operator delete (t)"). */
8431 }
8432 }
8433 }
8436 {
8442 {
8445 }
8448 call = (build_min_non_dep_call_vec
8452 orig_args));
8457 }
8459 /* Free all the conversions we allocated. */
8466 }
8468 /* Wrapper for above. */
8470 tree
8474 {
8475 tree ret;
8481 }
8483 /* Returns true iff standard conversion sequence ICS1 is a proper
8484 subsequence of ICS2. */
8486 static bool
8488 {
8489 /* We can assume that a conversion of the same code
8490 between the same types indicates a subsequence since we only get
8491 here if the types we are converting from are the same. */
8498 {
8508 /* At this point, ICS1 cannot be a proper subsequence of
8509 ICS2. We can get a USER_CONV when we are comparing the
8510 second standard conversion sequence of two user conversion
8511 sequences. */
8521 }
8522 }
8524 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8525 be any _TYPE nodes. */
8527 bool
8529 {
8533 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8534 considers every class derived from itself. */
8537 }
8539 /* We build the ICS for an implicit object parameter as a pointer
8540 conversion sequence. However, such a sequence should be compared
8541 as if it were a reference conversion sequence. If ICS is the
8542 implicit conversion sequence for an implicit object parameter,
8543 modify it accordingly. */
8545 static void
8547 {
8549 {
8550 /* [over.match.funcs]
8552 For non-static member functions, the type of the
8553 implicit object parameter is "reference to cv X"
8554 where X is the class of which the function is a
8555 member and cv is the cv-qualification on the member
8556 function declaration. */
8558 tree reference_type;
8560 /* The `this' parameter is a pointer to a class type. Make the
8561 implicit conversion talk about a reference to that same class
8562 type. */
8575 }
8576 }
8578 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8579 and return the initial reference binding conversion. Otherwise,
8580 leave *ICS unchanged and return NULL. */
8584 {
8586 {
8591 }
8594 }
8596 /* Compare two implicit conversion sequences according to the rules set out in
8597 [over.ics.rank]. Return values:
8599 1: ics1 is better than ics2
8600 -1: ics2 is better than ics1
8601 0: ics1 and ics2 are indistinguishable */
8603 static int
8605 {
8606 tree from_type1;
8607 tree from_type2;
8608 tree to_type1;
8609 tree to_type2;
8616 /* REF_BINDING is nonzero if the result of the conversion sequence
8617 is a reference type. In that case REF_CONV is the reference
8618 binding conversion. */
8622 /* Compare badness before stripping the reference conversion. */
8628 /* Handle implicit object parameters. */
8632 /* Handle reference parameters. */
8636 /* List-initialization sequence L1 is a better conversion sequence than
8637 list-initialization sequence L2 if L1 converts to
8638 std::initializer_list<X> for some X and L2 does not. */
8644 /* [over.ics.rank]
8646 When comparing the basic forms of implicit conversion sequences (as
8647 defined in _over.best.ics_)
8649 --a standard conversion sequence (_over.ics.scs_) is a better
8650 conversion sequence than a user-defined conversion sequence
8651 or an ellipsis conversion sequence, and
8653 --a user-defined conversion sequence (_over.ics.user_) is a
8654 better conversion sequence than an ellipsis conversion sequence
8655 (_over.ics.ellipsis_). */
8656 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8657 mismatch. If both ICS are bad, we try to make a decision based on
8658 what would have happened if they'd been good. This is not an
8659 extension, we'll still give an error when we build up the call; this
8660 just helps us give a more helpful error message. */
8670 /* Both conversions are ellipsis conversions. */
8673 /* User-defined conversion sequence U1 is a better conversion sequence
8674 than another user-defined conversion sequence U2 if they contain the
8675 same user-defined conversion operator or constructor and if the sec-
8676 ond standard conversion sequence of U1 is better than the second
8677 standard conversion sequence of U2. */
8679 /* Handle list-conversion with the same code even though it isn't always
8680 ranked as a user-defined conversion and it doesn't have a second
8681 standard conversion sequence; it will still have the desired effect.
8682 Specifically, we need to do the reference binding comparison at the
8683 end of this function. */
8686 {
8702 {
8705 }
8706 else
8707 {
8708 /* For ambiguous or aggregate conversions, use the target type as
8709 a proxy for the conversion function. */
8712 }
8714 /* We can just fall through here, after setting up
8715 FROM_TYPE1 and FROM_TYPE2. */
8718 }
8719 else
8720 {
8724 /* We're dealing with two standard conversion sequences.
8726 [over.ics.rank]
8728 Standard conversion sequence S1 is a better conversion
8729 sequence than standard conversion sequence S2 if
8731 --S1 is a proper subsequence of S2 (comparing the conversion
8732 sequences in the canonical form defined by _over.ics.scs_,
8733 excluding any Lvalue Transformation; the identity
8734 conversion sequence is considered to be a subsequence of
8735 any non-identity conversion sequence */
8746 }
8748 /* One sequence can only be a subsequence of the other if they start with
8749 the same type. They can start with different types when comparing the
8750 second standard conversion sequence in two user-defined conversion
8751 sequences. */
8753 {
8758 }
8760 /* [over.ics.rank]
8762 Or, if not that,
8764 --the rank of S1 is better than the rank of S2 (by the rules
8765 defined below):
8767 Standard conversion sequences are ordered by their ranks: an Exact
8768 Match is a better conversion than a Promotion, which is a better
8769 conversion than a Conversion.
8771 Two conversion sequences with the same rank are indistinguishable
8772 unless one of the following rules applies:
8774 --A conversion that does not a convert a pointer, pointer to member,
8775 or std::nullptr_t to bool is better than one that does.
8777 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8778 so that we do not have to check it explicitly. */
8787 /* A conversion from scalar arithmetic type to complex is worse than a
8788 conversion between scalar arithmetic types. */
8795 {
8798 else
8800 }
8806 {
8811 }
8812 /* The rules for pointers to members A::* are just like the rules
8813 for pointers A*, except opposite: if B is derived from A then
8814 A::* converts to B::*, not vice versa. For that reason, we
8815 switch the from_ and to_ variables here. */
8822 {
8827 }
8832 {
8833 /* This was one of the pointer or pointer-like conversions.
8835 [over.ics.rank]
8837 --If class B is derived directly or indirectly from class A,
8838 conversion of B* to A* is better than conversion of B* to
8839 void*, and conversion of A* to void* is better than
8840 conversion of B* to void*. */
8843 {
8845 deref_from_type2))
8848 deref_from_type1))
8850 }
8853 {
8855 {
8857 {
8859 deref_to_type1))
8861 }
8862 /* We know that DEREF_TO_TYPE1 is `void' here. */
8864 deref_to_type2))
8866 }
8867 }
8870 {
8871 /* [over.ics.rank]
8873 --If class B is derived directly or indirectly from class A
8874 and class C is derived directly or indirectly from B,
8876 --conversion of C* to B* is better than conversion of C* to
8877 A*,
8879 --conversion of B* to A* is better than conversion of C* to
8880 A* */
8882 {
8884 deref_to_type2))
8887 deref_to_type1))
8889 }
8891 {
8893 deref_from_type1))
8896 deref_from_type2))
8898 }
8899 }
8900 }
8903 {
8906 /* [over.ics.rank]
8908 --binding of an expression of type C to a reference of type
8909 B& is better than binding an expression of type C to a
8910 reference of type A&
8912 --conversion of C to B is better than conversion of C to A, */
8915 {
8920 }
8921 }
8924 {
8927 /* [over.ics.rank]
8929 --binding of an expression of type B to a reference of type
8930 A& is better than binding an expression of type C to a
8931 reference of type A&,
8933 --conversion of B to A is better than conversion of C to A */
8936 {
8941 }
8942 }
8944 /* [over.ics.rank]
8946 --S1 and S2 differ only in their qualification conversion and yield
8947 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8948 qualification signature of type T1 is a proper subset of the cv-
8949 qualification signature of type T2 */
8953 {
8957 }
8959 /* [over.ics.rank]
8961 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8962 to an implicit object parameter of a non-static member function
8963 declared without a ref-qualifier, and either S1 binds an lvalue
8964 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8965 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8966 draft standard, 13.3.3.2)
8968 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8969 types to which the references refer are the same type except for
8970 top-level cv-qualifiers, and the type to which the reference
8971 initialized by S2 refers is more cv-qualified than the type to
8972 which the reference initialized by S1 refers.
8974 DR 1328 [over.match.best]: the context is an initialization by
8975 conversion function for direct reference binding (13.3.1.6) of a
8976 reference to function type, the return type of F1 is the same kind of
8977 reference (i.e. lvalue or rvalue) as the reference being initialized,
8978 and the return type of F2 is not. */
8981 {
8988 {
8992 /* Don't prefer a bad conversion that drops cv-quals to a bad
8993 conversion with the wrong rvalueness. */
8997 }
9000 {
9004 {
9005 /* Prefer the one that drops fewer cv-quals. */
9010 }
9012 }
9013 }
9015 /* Neither conversion sequence is better than the other. */
9017 }
9019 /* The source type for this standard conversion sequence. */
9021 static tree
9023 {
9025 {
9030 }
9032 }
9034 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9035 a pointer to LOSER and re-running joust to produce the warning if WINNER
9036 is actually used. */
9038 static void
9040 {
9046 }
9048 /* Compare two candidates for overloading as described in
9049 [over.match.best]. Return values:
9051 1: cand1 is better than cand2
9052 -1: cand2 is better than cand1
9053 0: cand1 and cand2 are indistinguishable */
9055 static int
9057 tsubst_flags_t complain)
9058 {
9064 /* Candidates that involve bad conversions are always worse than those
9065 that don't. */
9071 /* If we have two pseudo-candidates for conversions to the same type,
9072 or two candidates for the same function, arbitrarily pick one. */
9077 /* Prefer a non-deleted function over an implicitly deleted move
9078 constructor or assignment operator. This differs slightly from the
9079 wording for issue 1402 (which says the move op is ignored by overload
9080 resolution), but this way produces better error messages. */
9084 {
9091 }
9093 /* a viable function F1
9094 is defined to be a better function than another viable function F2 if
9095 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9096 ICSi(F2), and then */
9098 /* for some argument j, ICSj(F1) is a better conversion sequence than
9099 ICSj(F2) */
9101 /* For comparing static and non-static member functions, we ignore
9102 the implicit object parameter of the non-static function. The
9103 standard says to pretend that the static function has an object
9104 parm, but that won't work with operator overloading. */
9107 {
9113 /* We're comparing a near-match list constructor and a near-match
9114 non-list constructor. Just treat them as unordered. */
9121 else
9122 {
9125 }
9126 }
9129 {
9135 {
9137 && warn_sign_promo
9149 {
9156 else
9161 {
9165 }
9166 else
9168 }
9171 {
9174 }
9176 }
9177 }
9179 /* warn about confusing overload resolution for user-defined conversions,
9180 either between a constructor and a conversion op, or between two
9181 conversion ops. */
9186 {
9192 else
9195 /* We don't want to complain about `X::operator T1 ()'
9196 beating `X::operator T2 () const', when T2 is a no less
9197 cv-qualified version of T1. */
9200 {
9205 {
9208 }
9211 }
9212 else
9218 {
9225 {
9227 }
9228 }
9229 else
9231 }
9236 /* DR 495 moved this tiebreaker above the template ones. */
9237 /* or, if not that,
9238 the context is an initialization by user-defined conversion (see
9239 _dcl.init_ and _over.match.user_) and the standard conversion
9240 sequence from the return type of F1 to the destination type (i.e.,
9241 the type of the entity being initialized) is a better conversion
9242 sequence than the standard conversion sequence from the return type
9243 of F2 to the destination type. */
9246 {
9250 }
9252 /* or, if not that,
9253 F1 is a non-template function and F2 is a template function
9254 specialization. */
9261 /* or, if not that,
9262 F1 and F2 are template functions and the function template for F1 is
9263 more specialized than the template for F2 according to the partial
9264 ordering rules. */
9267 {
9268 winner = more_specialized_fn
9271 /* [temp.func.order]: The presence of unused ellipsis and default
9272 arguments has no effect on the partial ordering of function
9273 templates. add_function_candidate() will not have
9274 counted the "this" argument for constructors. */
9278 }
9280 // C++ Concepts
9281 // or, if not that, F1 is more constrained than F2.
9283 {
9287 }
9289 /* Check whether we can discard a builtin candidate, either because we
9290 have two identical ones or matching builtin and non-builtin candidates.
9292 (Pedantically in the latter case the builtin which matched the user
9293 function should not be added to the overload set, but we spot it here.
9295 [over.match.oper]
9296 ... the builtin candidates include ...
9297 - do not have the same parameter type list as any non-template
9298 non-member candidate. */
9301 {
9307 {
9309 /* Two built-in candidates; arbitrarily pick one. */
9312 /* cand1 is built-in; prefer cand2. */
9314 else
9315 /* cand2 is built-in; prefer cand1. */
9317 }
9318 }
9320 /* For candidates of a multi-versioned function, make the version with
9321 the highest priority win. This version will be checked for dispatching
9322 first. If this version can be inlined into the caller, the front-end
9323 will simply make a direct call to this function. */
9329 {
9335 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9336 is possible that cand1->fn and cand2->fn are function versions but of
9337 different functions. Check types to see if they are versions of the same
9338 function. */
9341 {
9342 /* Always make the version with the higher priority, more
9343 specialized, win. */
9347 else
9349 }
9350 }
9352 /* If the two function declarations represent the same function (this can
9353 happen with declarations in multiple scopes and arg-dependent lookup),
9354 arbitrarily choose one. But first make sure the default args we're
9355 using match. */
9358 {
9365 {
9366 /* Don't crash if the fn is variadic. */
9371 }
9379 {
9382 {
9384 {
9386 {
9388 "default argument mismatch in "
9390 {
9395 }
9396 }
9397 else
9399 }
9400 else
9403 }
9406 }
9409 }
9411 tweak:
9413 /* Extension: If the worst conversion for one candidate is worse than the
9414 worst conversion for the other, take the first. */
9416 {
9421 {
9426 }
9432 {
9433 /* Don't choose a deleted function over ambiguity. */
9437 {
9439 "ISO C++ says that these are ambiguous, even "
9440 "though the worst conversion for the first is better than "
9444 }
9445 else
9448 }
9449 }
9453 }
9455 /* Given a list of candidates for overloading, find the best one, if any.
9456 This algorithm has a worst case of O(2n) (winner is last), and a best
9457 case of O(n/2) (totally ambiguous); much better than a sorting
9458 algorithm. */
9462 {
9467 /* Walk through the list once, comparing each current champ to the next
9468 candidate, knocking out a candidate or two with each comparison. */
9471 {
9475 else
9476 {
9478 {
9483 }
9484 else
9485 {
9488 }
9491 }
9492 }
9494 /* Make sure the champ is better than all the candidates it hasn't yet
9495 been compared to. */
9498 challenger != champ
9501 {
9505 }
9508 }
9510 /* Returns nonzero if things of type FROM can be converted to TO. */
9512 bool
9514 {
9516 /* implicit_conversion only considers user-defined conversions
9517 if it has an expression for the call argument list. */
9521 }
9523 /* Returns nonzero if things of type FROM can be converted to TO with a
9524 standard conversion. */
9526 bool
9528 {
9530 }
9532 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9534 bool
9536 tsubst_flags_t complain)
9537 {
9542 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9544 /* We want to discard any access checks done for this test,
9545 as we might not be in the appropriate access context and
9546 we'll do the check again when we actually perform the
9547 conversion. */
9554 /* Discard the access checks now. */
9556 /* Free all the conversions we allocated. */
9560 }
9562 /* Like can_convert_arg, but allows dubious conversions as well. */
9564 bool
9566 tsubst_flags_t complain)
9567 {
9571 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9573 /* Try to perform the conversion. */
9576 /* Free all the conversions we allocated. */
9580 }
9582 /* Convert EXPR to TYPE. Return the converted expression.
9584 Note that we allow bad conversions here because by the time we get to
9585 this point we are committed to doing the conversion. If we end up
9586 doing a bad conversion, convert_like will complain. */
9588 tree
9591 {
9599 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9607 {
9609 {
9610 /* If expr has unknown type, then it is an overloaded function.
9611 Call instantiate_type to get good error messages. */
9616 else
9619 }
9621 }
9623 {
9624 /* In a template, we are only concerned about determining the
9625 type of non-dependent expressions, so we do not have to
9626 perform the actual conversion. But for initializers, we
9627 need to be able to perform it at instantiation
9628 (or instantiate_non_dependent_expr) time. */
9632 }
9633 else
9636 /* Free all the conversions we allocated. */
9640 }
9642 tree
9644 {
9646 LOOKUP_IMPLICIT);
9647 }
9649 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9650 permitted. If the conversion is valid, the converted expression is
9651 returned. Otherwise, NULL_TREE is returned, except in the case
9652 that TYPE is a class type; in that case, an error is issued. If
9653 C_CAST_P is true, then this direct-initialization is taking
9654 place as part of a static_cast being attempted as part of a C-style
9655 cast. */
9657 tree
9659 tree expr,
9661 tsubst_flags_t complain)
9662 {
9668 /* [dcl.init]
9670 If the destination type is a (possibly cv-qualified) class type:
9672 -- If the initialization is direct-initialization ...,
9673 constructors are considered. ... If no constructor applies, or
9674 the overload resolution is ambiguous, the initialization is
9675 ill-formed. */
9677 {
9683 }
9685 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9689 c_cast_p,
9693 else
9696 c_cast_p,
9697 complain);
9699 /* Free all the conversions we allocated. */
9703 }
9705 /* When initializing a reference that lasts longer than a full-expression,
9706 this special rule applies:
9708 [class.temporary]
9710 The temporary to which the reference is bound or the temporary
9711 that is the complete object to which the reference is bound
9712 persists for the lifetime of the reference.
9714 The temporaries created during the evaluation of the expression
9715 initializing the reference, except the temporary to which the
9716 reference is bound, are destroyed at the end of the
9717 full-expression in which they are created.
9719 In that case, we store the converted expression into a new
9720 VAR_DECL in a new scope.
9722 However, we want to be careful not to create temporaries when
9723 they are not required. For example, given:
9725 struct B {};
9726 struct D : public B {};
9727 D f();
9728 const B& b = f();
9730 there is no need to copy the return value from "f"; we can just
9731 extend its lifetime. Similarly, given:
9733 struct S {};
9734 struct T { operator S(); };
9735 T t;
9736 const S& s = t;
9738 we can extend the lifetime of the return value of the conversion
9739 operator.
9741 The next several functions are involved in this lifetime extension. */
9743 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9744 reference is being bound to a temporary. Create and return a new
9745 VAR_DECL with the indicated TYPE; this variable will store the value to
9746 which the reference is bound. */
9748 tree
9750 {
9751 tree var;
9753 /* Create the variable. */
9756 /* Register the variable. */
9759 {
9760 /* Namespace-scope or local static; give it a mangled name. */
9761 /* FIXME share comdat with decl? */
9762 tree name;
9771 }
9772 else
9773 /* Create a new cleanup level if necessary. */
9777 }
9779 /* EXPR is the initializer for a variable DECL of reference or
9780 std::initializer_list type. Create, push and return a new VAR_DECL
9781 for the initializer so that it will live as long as DECL. Any
9782 cleanup for the new variable is returned through CLEANUP, and the
9783 code to initialize the new variable is returned through INITP. */
9785 static tree
9788 {
9789 tree init;
9790 tree type;
9791 tree var;
9793 /* Create the temporary variable. */
9797 /* If the rvalue is the result of a function call it will be
9798 a TARGET_EXPR. If it is some other construct (such as a
9799 member access expression where the underlying object is
9800 itself the result of a function call), turn it into a
9801 TARGET_EXPR here. It is important that EXPR be a
9802 TARGET_EXPR below since otherwise the INIT_EXPR will
9803 attempt to make a bitwise copy of EXPR to initialize
9804 VAR. */
9810 {
9814 }
9816 /* Recursively extend temps in this initializer. */
9820 /* Any reference temp has a non-trivial initializer. */
9823 /* If the initializer is constant, put it in DECL_INITIAL so we get
9824 static initialization and use in constant expressions. */
9827 {
9829 {
9830 /* 5.19 says that a constant expression can include an
9831 lvalue-rvalue conversion applied to "a glvalue of literal type
9832 that refers to a non-volatile temporary object initialized
9833 with a constant expression". Rather than try to communicate
9834 that this VAR_DECL is a temporary, just mark it constexpr.
9836 Currently this is only useful for initializer_list temporaries,
9837 since reference vars can't appear in constant expressions. */
9841 }
9844 }
9845 else
9846 /* Create the INIT_EXPR that will initialize the temporary
9847 variable. */
9850 {
9855 else
9856 {
9860 }
9862 /* We must be careful to destroy the temporary only
9863 after its initialization has taken place. If the
9864 initialization throws an exception, then the
9865 destructor should not be run. We cannot simply
9866 transform INIT into something like:
9868 (INIT, ({ CLEANUP_STMT; }))
9870 because emit_local_var always treats the
9871 initializer as a full-expression. Thus, the
9872 destructor would run too early; it would run at the
9873 end of initializing the reference variable, rather
9874 than at the end of the block enclosing the
9875 reference variable.
9877 The solution is to pass back a cleanup expression
9878 which the caller is responsible for attaching to
9879 the statement tree. */
9880 }
9881 else
9882 {
9885 {
9888 tls_aggregates);
9889 else
9891 static_aggregates);
9892 }
9893 else
9894 /* Check whether the dtor is callable. */
9896 }
9897 /* Avoid -Wunused-variable warning (c++/38958). */
9904 }
9906 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9907 initializing a variable of that TYPE. */
9909 tree
9912 {
9920 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9926 {
9928 {
9937 else
9941 }
9943 }
9946 /* Perform the conversion. */
9949 /* We gave an error in build_user_type_conversion_1. */
9951 else
9954 /* Free all the conversions we allocated. */
9958 }
9960 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9961 which is bound either to a reference or a std::initializer_list. */
9963 static tree
9965 {
9970 {
9974 }
9977 /* Deal with binding to a subobject. */
9981 {
9989 }
9991 }
9993 /* INIT is part of the initializer for DECL. If there are any
9994 reference or initializer lists being initialized, extend their
9995 lifetime to match that of DECL. */
9997 tree
9999 {
10006 {
10007 /* The temporary array underlying a std::initializer_list
10008 is handled like a reference temporary. */
10013 {
10017 }
10018 }
10020 {
10026 }
10029 }
10031 /* Returns true iff an initializer for TYPE could contain temporaries that
10032 need to be extended because they are bound to references or
10033 std::initializer_list. */
10035 bool
10037 {
10042 {
10049 }
10051 }
10053 /* Returns true iff TYPE is some variant of std::initializer_list. */
10055 bool
10057 {
10058 /* Look through typedefs. */
10067 }
10069 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10070 will accept an argument list of a single std::initializer_list<T>. */
10072 bool
10074 {
10076 tree arg;
10088 /* There are more non-defaulted parms. */
10092 }