| blob | 0e8840bb07ed04898403ddd10dc97ab61f4d4e6f |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987-2015 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) and
4 modified by Brendan Kehoe (brendan@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
23 /* High-level class interface. */
50 /* The various kinds of conversion. */
53 ck_identity,
54 ck_lvalue,
55 ck_qual,
56 ck_std,
57 ck_ptr,
58 ck_pmem,
59 ck_base,
60 ck_ref_bind,
61 ck_user,
62 ck_ambig,
63 ck_list,
64 ck_aggr,
65 ck_rvalue
68 /* The rank of the conversion. Order of the enumerals matters; better
69 conversions should come earlier in the list. */
72 cr_identity,
73 cr_exact,
74 cr_promotion,
75 cr_std,
76 cr_pbool,
77 cr_user,
78 cr_ellipsis,
79 cr_bad
82 /* An implicit conversion sequence, in the sense of [over.best.ics].
83 The first conversion to be performed is at the end of the chain.
84 That conversion is always a cr_identity conversion. */
88 /* The kind of conversion represented by this step. */
89 conversion_kind kind;
90 /* The rank of this conversion. */
91 conversion_rank rank;
95 /* True if this conversion would be permitted with a bending of
96 language standards, e.g. disregarding pointer qualifiers or
97 converting integers to pointers. */
99 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
100 temporary should be created to hold the result of the
101 conversion. */
103 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
104 from a pointer-to-derived to pointer-to-base is being performed. */
106 /* If KIND is ck_ref_bind, true when either an lvalue reference is
107 being bound to an lvalue expression or an rvalue reference is
108 being bound to an rvalue expression. If KIND is ck_rvalue,
109 true when we should treat an lvalue as an rvalue (12.8p33). If
110 KIND is ck_base, always false. */
113 /* The type of the expression resulting from the conversion. */
114 tree type;
116 /* The next conversion in the chain. Since the conversions are
117 arranged from outermost to innermost, the NEXT conversion will
118 actually be performed before this conversion. This variant is
119 used only when KIND is neither ck_identity, ck_ambig nor
120 ck_list. Please use the next_conversion function instead
121 of using this field directly. */
123 /* The expression at the beginning of the conversion chain. This
124 variant is used only if KIND is ck_identity or ck_ambig. */
125 tree expr;
126 /* The array of conversions for an initializer_list, so this
127 variant is used only when KIN D is ck_list. */
130 /* The function candidate corresponding to this conversion
131 sequence. This field is only used if KIND is ck_user. */
133 };
135 #define CONVERSION_RANK(NODE) \
136 ((NODE)->bad_p ? cr_bad \
137 : (NODE)->ellipsis_p ? cr_ellipsis \
138 : (NODE)->user_conv_p ? cr_user \
139 : (NODE)->rank)
141 #define BAD_CONVERSION_RANK(NODE) \
142 ((NODE)->ellipsis_p ? cr_ellipsis \
143 : (NODE)->user_conv_p ? cr_user \
144 : (NODE)->rank)
153 tsubst_flags_t);
157 #define convert_like(CONV, EXPR, COMPLAIN) \
158 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
161 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
162 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
170 tsubst_flags_t);
185 static void add_builtin_candidates
188 static void add_builtin_candidate
192 static void build_builtin_candidate
202 tsubst_flags_t);
205 tsubst_flags_t);
225 tsubst_flags_t);
229 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
230 NAME can take many forms... */
232 bool
234 {
235 /* Just accept something we've already complained about. */
244 {
250 else
252 }
253 else
254 {
255 /* In the case of:
257 template <class T> struct S { ~S(); };
258 int i;
259 i.~S();
261 NAME will be a class template. */
264 }
269 }
271 /* We want the address of a function or method. We avoid creating a
272 pointer-to-member function. */
274 tree
276 {
279 /* We have to do these by hand to avoid real pointer to member
280 functions. */
282 {
284 {
288 complain);
289 }
291 }
292 else
296 }
298 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
299 POINTER_TYPE to those. Note, pointer to member function types
300 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
301 two variants. build_call_a is the primitive taking an array of
302 arguments, while build_call_n is a wrapper that handles varargs. */
304 tree
306 {
309 else
310 {
320 }
321 }
323 /* Update various flags in cfun and the call itself based on what is being
324 called. Split out of build_call_a so that bot_manip can use it too. */
326 void
328 {
332 /* We check both the decl and the type; a function may be known not to
333 throw without being declared throw(). */
347 }
349 tree
351 {
352 tree decl;
353 tree result_type;
354 tree fntype;
364 /* An rvalue has no cv-qualifiers. */
375 {
376 /* We invoke build_call directly for several library
377 functions. These may have been declared normally if
378 we're building libgcc, so we can't just check
379 DECL_ARTIFICIAL. */
384 }
390 /* Don't pass empty class objects by value. This is useful
391 for tags in STL, which are used to control overload resolution.
392 We don't need to handle other cases of copying empty classes. */
395 {
399 {
403 }
404 }
407 }
409 /* New overloading code. */
417 };
419 /* Information for providing diagnostics about why overloading failed. */
422 rr_none,
423 rr_arity,
424 rr_explicit_conversion,
425 rr_template_conversion,
426 rr_arg_conversion,
427 rr_bad_arg_conversion,
428 rr_template_unification,
429 rr_invalid_copy
430 };
433 /* The index of the argument, 0-based. */
435 /* The actual argument or its type. */
436 tree from;
437 /* The type of the parameter. */
438 tree to_type;
439 };
444 /* Information about an arity mismatch. */
446 /* The expected number of arguments. */
448 /* The actual number of arguments in the call. */
450 /* Whether the call was a varargs call. */
453 /* Information about an argument conversion mismatch. */
455 /* Same, but for bad argument conversions. */
457 /* Information about template unification failures. These are the
458 parameters passed to fn_type_unification. */
460 tree tmpl;
461 tree explicit_targs;
465 tree return_type;
466 unification_kind_t strict;
469 /* Information about template instantiation failures. These are the
470 parameters passed to instantiate_template. */
472 tree tmpl;
473 tree targs;
476 };
479 /* The FUNCTION_DECL that will be called if this candidate is
480 selected by overload resolution. */
481 tree fn;
482 /* If not NULL_TREE, the first argument to use when calling this
483 function. */
484 tree first_arg;
485 /* The rest of the arguments to use when calling this function. If
486 there are no further arguments this may be NULL or it may be an
487 empty vector. */
489 /* The implicit conversion sequences for each of the arguments to
490 FN. */
492 /* The number of implicit conversion sequences. */
494 /* If FN is a user-defined conversion, the standard conversion
495 sequence from the type returned by FN to the desired destination
496 type. */
499 /* If FN is a member function, the binfo indicating the path used to
500 qualify the name of FN at the call site. This path is used to
501 determine whether or not FN is accessible if it is selected by
502 overload resolution. The DECL_CONTEXT of FN will always be a
503 (possibly improper) base of this binfo. */
504 tree access_path;
505 /* If FN is a non-static member function, the binfo indicating the
506 subobject to which the `this' pointer should be converted if FN
507 is selected by overload resolution. The type pointed to by
508 the `this' pointer must correspond to the most derived class
509 indicated by the CONVERSION_PATH. */
510 tree conversion_path;
511 tree template_decl;
512 tree explicit_targs;
517 /* The flags active in add_candidate. */
519 };
521 /* Returns true iff T is a null pointer constant in the sense of
522 [conv.ptr]. */
524 bool
526 {
527 /* [conv.ptr]
529 A null pointer constant is an integral constant expression
530 (_expr.const_) rvalue of integer type that evaluates to zero or
531 an rvalue of type std::nullptr_t. */
535 {
536 /* Core issue 903 says only literal 0 is a null pointer constant. */
542 }
544 }
546 /* Returns true iff T is a null member pointer value (4.11). */
548 bool
550 {
559 else
561 }
563 /* Returns nonzero if PARMLIST consists of only default parms,
564 ellipsis, and/or undeduced parameter packs. */
566 bool
568 {
575 }
577 /* Allocate N bytes of memory from the conversion obstack. The memory
578 is zeroed before being returned. */
582 {
585 {
588 }
592 }
594 /* Allocate rejection reasons. */
598 {
603 }
607 {
613 }
617 {
624 }
628 {
635 }
639 {
645 }
649 {
655 }
662 {
669 /* Copy args to our own storage. */
677 }
681 {
683 }
687 {
690 }
692 /* Dynamically allocate a conversion. */
696 {
701 }
703 #ifdef ENABLE_CHECKING
705 /* Make sure that all memory on the conversion obstack has been
706 freed. */
708 void
710 {
714 }
718 /* Dynamically allocate an array of N conversions. */
722 {
724 }
728 {
732 /* Note that the caller is responsible for filling in t->cand for
733 user-defined conversions. */
739 {
755 }
761 }
763 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
764 specialization of std::initializer_list<T>, if such a conversion is
765 possible. */
769 {
775 tree val;
777 /* Within a list-initialization we can have more user-defined
778 conversions. */
780 /* But no narrowing conversions. */
783 /* Can't make an array of these types. */
790 {
791 conversion *sub
798 }
806 {
814 }
817 }
819 /* Return the next conversion of the conversion chain (if applicable),
820 or NULL otherwise. Please use this function instead of directly
821 accessing fields of struct conversion. */
825 {
832 }
834 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
835 is a valid aggregate initializer for array type ATYPE. */
837 static bool
839 {
843 {
849 else
851 complain);
854 }
856 }
858 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
859 aggregate class, if such a conversion is possible. */
863 {
869 /* We already called reshape_init in implicit_conversion. */
871 /* The conversions within the init-list aren't affected by the enclosing
872 context; they're always simple copy-initialization. */
876 {
878 tree val;
884 /* Value-initialization of reference is ill-formed. */
886 else
887 {
891 }
897 else
899 complain);
906 }
918 }
920 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
921 array type, if such a conversion is possible. */
925 {
930 tree val;
935 /* We might need to propagate the size from the element to the array. */
940 {
944 }
949 {
950 conversion *sub
962 }
971 }
973 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
974 complex type, if such a conversion is possible. */
978 tsubst_flags_t complain)
979 {
984 tree val;
995 {
996 conversion *sub
1008 }
1017 }
1019 /* Build a representation of the identity conversion from EXPR to
1020 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1024 {
1032 }
1034 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1035 were multiple user-defined conversions to accomplish the job.
1036 Build a conversion that indicates that ambiguity. */
1040 {
1048 }
1050 tree
1052 {
1056 }
1058 /* Returns the standard conversion path (see [conv]) from type FROM to type
1059 TO, if any. For proper handling of null pointer constants, you must
1060 also pass the expression EXPR to convert from. If C_CAST_P is true,
1061 this conversion is coming from a C-style cast. */
1066 {
1070 tree qualified_to;
1074 {
1077 }
1083 {
1085 {
1091 }
1093 {
1094 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1097 }
1098 }
1105 {
1109 }
1111 {
1113 {
1114 tree bitfield_type;
1117 {
1120 }
1121 }
1125 }
1127 /* Allow conversion between `__complex__' data types. */
1129 {
1130 /* The standard conversion sequence to convert FROM to TO is
1131 the standard conversion sequence to perform componentwise
1132 conversion. */
1137 {
1140 }
1141 else
1145 }
1148 {
1152 }
1154 /* [conv.ptr]
1155 A null pointer constant can be converted to a pointer type; ... A
1156 null pointer constant of integral type can be converted to an
1157 rvalue of type std::nullptr_t. */
1165 {
1166 /* For backwards brain damage compatibility, allow interconversion of
1167 pointers and integers with a pedwarn. */
1170 }
1172 {
1173 /* For backwards brain damage compatibility, allow interconversion of
1174 enums and integers with a pedwarn. */
1177 }
1180 {
1181 tree to_pointee;
1182 tree from_pointee;
1187 ;
1191 {
1193 /* Don't try to apply restrict to void. */
1195 from = build_pointer_type
1198 }
1200 {
1205 && (same_type_ignoring_top_level_qualifiers_p
1208 {
1212 }
1215 }
1218 /* [conv.ptr]
1220 An rvalue of type "pointer to cv D," where D is a
1221 class type, can be converted to an rvalue of type
1222 "pointer to cv B," where B is a base class (clause
1223 _class.derived_) of D. If B is an inaccessible
1224 (clause _class.access_) or ambiguous
1225 (_class.member.lookup_) base class of D, a program
1226 that necessitates this conversion is ill-formed.
1227 Therefore, we use DERIVED_FROM_P, and do not check
1228 access or uniqueness. */
1230 {
1231 from =
1237 }
1240 {
1243 }
1244 else
1245 {
1248 }
1253 /* In a C-style cast, we ignore CV-qualification because we
1254 are allowed to perform a static_cast followed by a
1255 const_cast. */
1260 /* converting from string constant to char *. */
1262 /* Allow conversions among compatible ObjC pointer types (base
1263 conversions have been already handled above). */
1268 {
1271 }
1272 else
1276 }
1278 {
1290 tbase,
1296 }
1298 {
1299 /* [conv.bool]
1301 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1302 to member type can be converted to a prvalue of type bool. ...
1303 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1304 std::nullptr_t can be converted to a prvalue of type bool; */
1310 {
1321 }
1324 }
1325 /* We don't check for ENUMERAL_TYPE here because there are no standard
1326 conversions to enum type. */
1327 /* As an extension, allow conversion to complex type. */
1329 {
1336 /* Give this a better rank if it's a promotion. */
1340 }
1346 {
1350 /* The derived-to-base conversion indicates the initialization
1351 of a parameter with base type from an object of a derived
1352 type. A temporary object is created to hold the result of
1353 the conversion unless we're binding directly to a reference. */
1355 }
1356 else
1363 }
1365 /* Returns nonzero if T1 is reference-related to T2. */
1367 bool
1369 {
1376 /* [dcl.init.ref]
1378 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1379 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1380 of T2. */
1384 }
1386 /* Returns nonzero if T1 is reference-compatible with T2. */
1388 static bool
1390 {
1391 /* [dcl.init.ref]
1393 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1394 reference-related to T2 and cv1 is the same cv-qualification as,
1395 or greater cv-qualification than, cv2. */
1398 }
1400 /* A reference of the indicated TYPE is being bound directly to the
1401 expression represented by the implicit conversion sequence CONV.
1402 Return a conversion sequence for this binding. */
1406 {
1407 tree t;
1414 /* [over.ics.rank]
1416 When a parameter of reference type binds directly
1417 (_dcl.init.ref_) to an argument expression, the implicit
1418 conversion sequence is the identity conversion, unless the
1419 argument expression has a type that is a derived class of the
1420 parameter type, in which case the implicit conversion sequence is
1421 a derived-to-base Conversion.
1423 If the parameter binds directly to the result of applying a
1424 conversion function to the argument expression, the implicit
1425 conversion sequence is a user-defined conversion sequence
1426 (_over.ics.user_), with the second standard conversion sequence
1427 either an identity conversion or, if the conversion function
1428 returns an entity of a type that is a derived class of the
1429 parameter type, a derived-to-base conversion. */
1431 {
1432 /* Represent the derived-to-base conversion. */
1434 /* We will actually be binding to the base-class subobject in
1435 the derived class, so we mark this conversion appropriately.
1436 That way, convert_like knows not to generate a temporary. */
1438 }
1440 }
1442 /* Returns the conversion path from type FROM to reference type TO for
1443 purposes of reference binding. For lvalue binding, either pass a
1444 reference type to FROM or an lvalue expression to EXPR. If the
1445 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1446 the conversion returned. If C_CAST_P is true, this
1447 conversion is coming from a C-style cast. */
1451 tsubst_flags_t complain)
1452 {
1456 tree tfrom;
1459 cp_lvalue_kind gl_kind;
1463 {
1468 }
1471 {
1473 /* DR 1288: Otherwise, if the initializer list has a single element
1474 of type E and ... [T's] referenced type is reference-related to E,
1475 the object or reference is initialized from that element... */
1477 {
1483 {
1487 }
1488 }
1489 /* Otherwise, if T is a reference type, a prvalue temporary of the
1490 type referenced by T is copy-list-initialized or
1491 direct-list-initialized, depending on the kind of initialization
1492 for the reference, and the reference is bound to that temporary. */
1495 skip:;
1496 }
1499 {
1504 else
1506 }
1508 {
1511 /* A class prvalue is not a glvalue. */
1513 }
1514 else
1522 /* Figure out whether or not the types are reference-related and
1523 reference compatible. We have do do this after stripping
1524 references from FROM. */
1526 /* If this is a C cast, first convert to an appropriately qualified
1527 type, so that we can later do a const_cast to the desired type. */
1533 /* Directly bind reference when target expression's type is compatible with
1534 the reference and expression is an lvalue. In DR391, the wording in
1535 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1536 const and rvalue references to rvalues of compatible class type.
1537 We should also do direct bindings for non-class xvalues. */
1539 && (gl_kind
1543 {
1544 /* [dcl.init.ref]
1546 If the initializer expression
1548 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1549 is reference-compatible with "cv2 T2,"
1551 the reference is bound directly to the initializer expression
1552 lvalue.
1554 [...]
1555 If the initializer expression is an rvalue, with T2 a class type,
1556 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1557 is bound to the object represented by the rvalue or to a sub-object
1558 within that object. */
1564 /* The top-level caller requested that we pretend that the lvalue
1565 be treated as an rvalue. */
1568 /* Handle rvalue reference to function properly. */
1569 conv->rvaluedness_matches_p
1571 else
1572 conv->rvaluedness_matches_p
1577 /* For the purposes of overload resolution, we ignore the fact
1578 this expression is a bitfield or packed field. (In particular,
1579 [over.ics.ref] says specifically that a function with a
1580 non-const reference parameter is viable even if the
1581 argument is a bitfield.)
1583 However, when we actually call the function we must create
1584 a temporary to which to bind the reference. If the
1585 reference is volatile, or isn't const, then we cannot make
1586 a temporary, so we just issue an error when the conversion
1587 actually occurs. */
1590 /* Don't allow binding of lvalues (other than function lvalues) to
1591 rvalue references. */
1597 /* Nor the reverse. */
1608 }
1609 /* [class.conv.fct] A conversion function is never used to convert a
1610 (possibly cv-qualified) object to the (possibly cv-qualified) same
1611 object type (or a reference to it), to a (possibly cv-qualified) base
1612 class of that type (or a reference to it).... */
1615 {
1616 /* [dcl.init.ref]
1618 If the initializer expression
1620 -- has a class type (i.e., T2 is a class type) can be
1621 implicitly converted to an lvalue of type "cv3 T3," where
1622 "cv1 T1" is reference-compatible with "cv3 T3". (this
1623 conversion is selected by enumerating the applicable
1624 conversion functions (_over.match.ref_) and choosing the
1625 best one through overload resolution. (_over.match_).
1627 the reference is bound to the lvalue result of the conversion
1628 in the second case. */
1630 complain);
1633 }
1635 /* From this point on, we conceptually need temporaries, even if we
1636 elide them. Only the cases above are "direct bindings". */
1640 /* [over.ics.rank]
1642 When a parameter of reference type is not bound directly to an
1643 argument expression, the conversion sequence is the one required
1644 to convert the argument expression to the underlying type of the
1645 reference according to _over.best.ics_. Conceptually, this
1646 conversion sequence corresponds to copy-initializing a temporary
1647 of the underlying type with the argument expression. Any
1648 difference in top-level cv-qualification is subsumed by the
1649 initialization itself and does not constitute a conversion. */
1651 /* [dcl.init.ref]
1653 Otherwise, the reference shall be an lvalue reference to a
1654 non-volatile const type, or the reference shall be an rvalue
1655 reference.
1657 We try below to treat this as a bad conversion to improve diagnostics,
1658 but if TO is an incomplete class, we need to reject this conversion
1659 now to avoid unnecessary instantiation. */
1664 /* We're generating a temporary now, but don't bind any more in the
1665 conversion (specifically, don't slice the temporary returned by a
1666 conversion operator). */
1669 /* Core issue 899: When [copy-]initializing a temporary to be bound
1670 to the first parameter of a copy constructor (12.8) called with
1671 a single argument in the context of direct-initialization,
1672 explicit conversion functions are also considered.
1674 So don't set LOOKUP_ONLYCONVERTING in that case. */
1685 {
1686 /* If initializing the temporary used a conversion function,
1687 recalculate the second conversion sequence. */
1691 {
1694 conversion *new_second
1700 }
1701 }
1704 /* This reference binding, unlike those above, requires the
1705 creation of a temporary. */
1709 /* [dcl.init.ref]
1711 Otherwise, the reference shall be an lvalue reference to a
1712 non-volatile const type, or the reference shall be an rvalue
1713 reference. */
1717 /* [dcl.init.ref]
1719 Otherwise, a temporary of type "cv1 T1" is created and
1720 initialized from the initializer expression using the rules for a
1721 non-reference copy initialization. If T1 is reference-related to
1722 T2, cv1 must be the same cv-qualification as, or greater
1723 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1728 }
1730 /* Returns the implicit conversion sequence (see [over.ics]) from type
1731 FROM to type TO. The optional expression EXPR may affect the
1732 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1733 true, this conversion is coming from a C-style cast. */
1738 {
1745 /* Other flags only apply to the primary function in overload
1746 resolution, or after we've chosen one. */
1751 /* FIXME: actually we don't want warnings either, but we can't just
1752 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1753 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1754 We really ought not to issue that warning until we've committed
1755 to that conversion. */
1758 /* Call reshape_init early to remove redundant braces. */
1763 {
1768 }
1772 else
1779 {
1783 /* As an extension, allow list-initialization of _Complex. */
1785 {
1789 }
1791 /* Allow conversion from an initializer-list with one element to a
1792 scalar type. */
1794 {
1796 tree elt;
1802 else
1808 {
1811 /* Too many levels of braces, i.e. '{{1}}'. */
1814 }
1815 }
1818 }
1824 {
1836 /* We used to try to bind a reference to a temporary here, but that
1837 is now handled after the recursive call to this function at the end
1838 of reference_binding. */
1840 }
1843 }
1845 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1846 functions. ARGS will not be changed until a single candidate is
1847 selected. */
1856 {
1874 }
1876 /* Return the number of remaining arguments in the parameter list
1877 beginning with ARG. */
1879 static int
1881 {
1886 n++;
1889 }
1891 /* Create an overload candidate for the function or method FN called
1892 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1893 FLAGS is passed on to implicit_conversion.
1895 This does not change ARGS.
1897 CTYPE, if non-NULL, is the type we want to pretend this function
1898 comes from for purposes of overload resolution. */
1905 tsubst_flags_t complain)
1906 {
1910 tree parmnode;
1916 /* At this point we should not see any functions which haven't been
1917 explicitly declared, except for friend functions which will have
1918 been found using argument dependent lookup. */
1921 /* The `this', `in_chrg' and VTT arguments to constructors are not
1922 considered in overload resolution. */
1924 {
1928 {
1931 }
1932 }
1933 else
1939 /* 13.3.2 - Viable functions [over.match.viable]
1940 First, to be a viable function, a candidate function shall have enough
1941 parameters to agree in number with the arguments in the list.
1943 We need to check this first; otherwise, checking the ICSes might cause
1944 us to produce an ill-formed template instantiation. */
1948 {
1952 }
1956 {
1960 }
1961 /* When looking for a function from a subobject from an implicit
1962 copy/move constructor/operator=, don't consider anything that takes (a
1963 reference to) an unrelated type. See c++/44909 and core 1092. */
1965 {
1971 else
1974 {
1977 ctype))
1979 }
1981 /* This only applies at the top level. */
1983 }
1988 /* Second, for F to be a viable function, there shall exist for each
1989 argument an implicit conversion sequence that converts that argument
1990 to the corresponding parameter of F. */
1995 {
1997 tree arg;
2006 else
2015 {
2021 /* The type of the implicit object parameter ('this') for
2022 overload resolution is not always the same as for the
2023 function itself; conversion functions are considered to
2024 be members of the class being converted, and functions
2025 introduced by a using-declaration are considered to be
2026 members of the class that uses them.
2028 Since build_over_call ignores the ICS for the `this'
2029 parameter, we can just change the parm type. */
2031 {
2032 parmtype = cp_build_qualified_type
2035 {
2036 /* If the function has a ref-qualifier, the implicit
2037 object parameter has reference type. */
2040 /* The special handling of 'this' conversions in compare_ics
2041 does not apply if there is a ref-qualifier. */
2043 }
2044 else
2045 {
2049 }
2050 }
2052 /* Core issue 899: When [copy-]initializing a temporary to be bound
2053 to the first parameter of a copy constructor (12.8) called with
2054 a single argument in the context of direct-initialization,
2055 explicit conversion functions are also considered.
2057 So set LOOKUP_COPY_PARM to let reference_binding know that
2058 it's being called in that context. We generalize the above
2059 to handle move constructors and template constructors as well;
2060 the standardese should soon be updated similarly. */
2064 && (same_type_ignoring_top_level_qualifiers_p
2066 {
2069 /* We allow user-defined conversions within init-lists, but
2070 don't list-initialize the copy parm, as that would mean
2071 using two levels of braces for the same type. */
2075 }
2076 else
2082 }
2083 else
2084 {
2088 }
2095 {
2099 }
2102 {
2105 }
2106 }
2108 out:
2111 }
2113 /* Create an overload candidate for the conversion function FN which will
2114 be invoked for expression OBJ, producing a pointer-to-function which
2115 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2116 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2117 passed on to implicit_conversion.
2119 Actually, we don't really care about FN; we care about the type it
2120 converts to. There may be multiple conversion functions that will
2121 convert to that type, and we rely on build_user_type_conversion_1 to
2122 choose the best one; so when we create our candidate, we record the type
2123 instead of the function. */
2129 tsubst_flags_t complain)
2130 {
2148 /* Don't bother looking up the same type twice. */
2153 {
2161 else
2166 {
2170 }
2174 {
2178 }
2179 else
2180 {
2184 }
2191 {
2194 }
2201 }
2205 {
2209 }
2213 }
2215 static void
2219 {
2233 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2234 conversion ops are allowed. We handle that here by just checking for
2235 boolean_type_node because other operators don't ask for it. COND_EXPR
2236 also does contextual conversion to bool for the first operand, but we
2237 handle that in build_conditional_expr, and type1 here is operand 2. */
2242 {
2249 {
2251 /* We need something for printing the candidate. */
2255 }
2257 {
2261 }
2263 }
2265 /* For COND_EXPR we rearranged the arguments; undo that now. */
2267 {
2272 complain);
2275 else
2276 {
2279 boolean_type_node);
2280 }
2281 }
2288 }
2290 static bool
2292 {
2294 }
2296 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2298 static bool
2300 {
2301 /* [over.built]
2303 In this section, the term promoted integral type is used to refer
2304 to those integral types which are preserved by integral promotion
2305 (including e.g. int and long but excluding e.g. char).
2306 Similarly, the term promoted arithmetic type refers to promoted
2307 integral types plus floating types. */
2311 }
2313 /* Create any builtin operator overload candidates for the operator in
2314 question given the converted operand types TYPE1 and TYPE2. The other
2315 args are passed through from add_builtin_candidates to
2316 build_builtin_candidate.
2318 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2319 If CODE is requires candidates operands of the same type of the kind
2320 of which TYPE1 and TYPE2 are, we add both candidates
2321 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2323 static void
2327 tsubst_flags_t complain)
2328 {
2330 {
2338 }
2341 {
2343 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2344 and VQ is either volatile or empty, there exist candidate operator
2345 functions of the form
2346 VQ T& operator++(VQ T&);
2347 T operator++(VQ T&, int);
2348 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2349 type other than bool, and VQ is either volatile or empty, there exist
2350 candidate operator functions of the form
2351 VQ T& operator--(VQ T&);
2352 T operator--(VQ T&, int);
2353 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2354 complete object type, and VQ is either volatile or empty, there exist
2355 candidate operator functions of the form
2356 T*VQ& operator++(T*VQ&);
2357 T*VQ& operator--(T*VQ&);
2358 T* operator++(T*VQ&, int);
2359 T* operator--(T*VQ&, int); */
2368 {
2371 }
2374 /* 7 For every cv-qualified or cv-unqualified object type T, there
2375 exist candidate operator functions of the form
2377 T& operator*(T*);
2379 8 For every function type T, there exist candidate operator functions of
2380 the form
2381 T& operator*(T*); */
2390 /* 9 For every type T, there exist candidate operator functions of the form
2391 T* operator+(T*);
2393 10For every promoted arithmetic type T, there exist candidate operator
2394 functions of the form
2395 T operator+(T);
2396 T operator-(T); */
2406 /* 11For every promoted integral type T, there exist candidate operator
2407 functions of the form
2408 T operator~(T); */
2415 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2416 is the same type as C2 or is a derived class of C2, T is a complete
2417 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2418 there exist candidate operator functions of the form
2419 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2420 where CV12 is the union of CV1 and CV2. */
2424 {
2432 }
2435 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2436 didate operator functions of the form
2437 LR operator*(L, R);
2438 LR operator/(L, R);
2439 LR operator+(L, R);
2440 LR operator-(L, R);
2441 bool operator<(L, R);
2442 bool operator>(L, R);
2443 bool operator<=(L, R);
2444 bool operator>=(L, R);
2445 bool operator==(L, R);
2446 bool operator!=(L, R);
2447 where LR is the result of the usual arithmetic conversions between
2448 types L and R.
2450 14For every pair of types T and I, where T is a cv-qualified or cv-
2451 unqualified complete object type and I is a promoted integral type,
2452 there exist candidate operator functions of the form
2453 T* operator+(T*, I);
2454 T& operator[](T*, I);
2455 T* operator-(T*, I);
2456 T* operator+(I, T*);
2457 T& operator[](I, T*);
2459 15For every T, where T is a pointer to complete object type, there exist
2460 candidate operator functions of the form112)
2461 ptrdiff_t operator-(T, T);
2463 16For every pointer or enumeration type T, there exist candidate operator
2464 functions of the form
2465 bool operator<(T, T);
2466 bool operator>(T, T);
2467 bool operator<=(T, T);
2468 bool operator>=(T, T);
2469 bool operator==(T, T);
2470 bool operator!=(T, T);
2472 17For every pointer to member type T, there exist candidate operator
2473 functions of the form
2474 bool operator==(T, T);
2475 bool operator!=(T, T); */
2482 {
2485 }
2498 {
2501 }
2503 {
2506 }
2507 /* Fall through. */
2523 {
2526 }
2529 {
2532 }
2540 {
2543 }
2545 {
2548 }
2551 /* 18For every pair of promoted integral types L and R, there exist candi-
2552 date operator functions of the form
2553 LR operator%(L, R);
2554 LR operator&(L, R);
2555 LR operator^(L, R);
2556 LR operator|(L, R);
2557 L operator<<(L, R);
2558 L operator>>(L, R);
2559 where LR is the result of the usual arithmetic conversions between
2560 types L and R. */
2568 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2572 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2573 type, VQ is either volatile or empty, and R is a promoted arithmetic
2574 type, there exist candidate operator functions of the form
2575 VQ L& operator=(VQ L&, R);
2576 VQ L& operator*=(VQ L&, R);
2577 VQ L& operator/=(VQ L&, R);
2578 VQ L& operator+=(VQ L&, R);
2579 VQ L& operator-=(VQ L&, R);
2581 20For every pair T, VQ), where T is any type and VQ is either volatile
2582 or empty, there exist candidate operator functions of the form
2583 T*VQ& operator=(T*VQ&, T*);
2585 21For every pair T, VQ), where T is a pointer to member type and VQ is
2586 either volatile or empty, there exist candidate operator functions of
2587 the form
2588 VQ T& operator=(VQ T&, T);
2590 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2591 unqualified complete object type, VQ is either volatile or empty, and
2592 I is a promoted integral type, there exist candidate operator func-
2593 tions of the form
2594 T*VQ& operator+=(T*VQ&, I);
2595 T*VQ& operator-=(T*VQ&, I);
2597 23For every triple L, VQ, R), where L is an integral or enumeration
2598 type, VQ is either volatile or empty, and R is a promoted integral
2599 type, there exist candidate operator functions of the form
2601 VQ L& operator%=(VQ L&, R);
2602 VQ L& operator<<=(VQ L&, R);
2603 VQ L& operator>>=(VQ L&, R);
2604 VQ L& operator&=(VQ L&, R);
2605 VQ L& operator^=(VQ L&, R);
2606 VQ L& operator|=(VQ L&, R); */
2610 {
2614 {
2617 }
2630 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2643 {
2646 }
2651 }
2656 /* [over.built]
2658 For every pair of promoted arithmetic types L and R, there
2659 exist candidate operator functions of the form
2661 LR operator?(bool, L, R);
2663 where LR is the result of the usual arithmetic conversions
2664 between types L and R.
2666 For every type T, where T is a pointer or pointer-to-member
2667 type, there exist candidate operator functions of the form T
2668 operator?(bool, T, T); */
2672 /* That's OK. */
2675 /* Otherwise, the types should be pointers. */
2679 /* We don't check that the two types are the same; the logic
2680 below will actually create two candidates; one in which both
2681 parameter types are TYPE1, and one in which both parameter
2682 types are TYPE2. */
2693 }
2695 /* Make sure we don't create builtin candidates with dependent types. */
2699 {
2700 /* Try to recover if one of the types is non-dependent. But if
2701 there's only one type, there's nothing we can do. */
2704 /* And we lose if both are dependent. */
2707 /* Or if they have different forms. */
2715 }
2717 /* If we're dealing with two pointer types or two enumeral types,
2718 we need candidates for both of them. */
2727 {
2729 {
2731 error_mark_node,
2732 error_mark_node,
2733 CPO_CONVERSION,
2734 tf_none);
2736 {
2737 build_builtin_candidate
2741 }
2742 }
2744 build_builtin_candidate
2746 build_builtin_candidate
2749 }
2751 build_builtin_candidate
2753 }
2755 tree
2757 {
2763 }
2765 /* There are three conditions of builtin candidates:
2767 1) bool-taking candidates. These are the same regardless of the input.
2768 2) pointer-pair taking candidates. These are generated for each type
2769 one of the input types converts to.
2770 3) arithmetic candidates. According to the standard, we should generate
2771 all of these, but I'm trying not to...
2773 Here we generate a superset of the possible candidates for this particular
2774 case. That is a subset of the full set the standard defines, plus some
2775 other cases which the standard disallows. add_builtin_candidate will
2776 filter out the invalid set. */
2778 static void
2782 {
2786 /* TYPES[i] is the set of possible builtin-operator parameter types
2787 we will consider for the Ith argument. */
2792 {
2795 else
2797 }
2800 {
2801 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2802 and VQ is either volatile or empty, there exist candidate operator
2803 functions of the form
2804 VQ T& operator++(VQ T&); */
2814 /* 24There also exist candidate operator functions of the form
2815 bool operator!(bool);
2816 bool operator&&(bool, bool);
2817 bool operator||(bool, bool); */
2820 build_builtin_candidate
2827 build_builtin_candidate
2845 /* Fall through. */
2849 }
2855 {
2857 ;
2859 {
2860 tree convs;
2868 {
2873 }
2879 {
2892 {
2898 }
2902 }
2903 }
2904 else
2905 {
2910 {
2916 }
2918 }
2919 }
2921 /* Run through the possible parameter types of both arguments,
2922 creating candidates with those parameter types. */
2924 {
2926 tree u;
2930 add_builtin_candidate
2933 else
2934 add_builtin_candidate
2937 }
2941 }
2944 /* If TMPL can be successfully instantiated as indicated by
2945 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2947 TMPL is the template. EXPLICIT_TARGS are any explicit template
2948 arguments. ARGLIST is the arguments provided at the call-site.
2949 This does not change ARGLIST. The RETURN_TYPE is the desired type
2950 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2951 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2952 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2960 tsubst_flags_t complain)
2961 {
2971 tree arg;
2973 tree fn;
2977 /* We don't do deduction on the in-charge parameter, the VTT
2978 parameter or 'this'. */
2980 {
2983 else
2985 }
2990 {
2993 else
2995 }
3005 {
3008 }
3012 {
3015 }
3020 args_without_in_chrg,
3021 nargs_without_in_chrg,
3026 {
3027 /* Don't repeat unification later if it already resulted in errors. */
3031 nargs_without_in_chrg,
3033 else
3036 }
3038 /* In [class.copy]:
3040 A member function template is never instantiated to perform the
3041 copy of a class object to an object of its class type.
3043 It's a little unclear what this means; the standard explicitly
3044 does allow a template to be used to copy a class. For example,
3045 in:
3047 struct A {
3048 A(A&);
3049 template <class T> A(const T&);
3050 };
3051 const A f ();
3052 void g () { A a (f ()); }
3054 the member template will be used to make the copy. The section
3055 quoted above appears in the paragraph that forbids constructors
3056 whose only parameter is (a possibly cv-qualified variant of) the
3057 class type, and a logical interpretation is that the intent was
3058 to forbid the instantiation of member templates which would then
3059 have that form. */
3061 {
3064 ctype))
3065 {
3068 }
3069 }
3072 /* Aha, this is a conversion function. */
3075 else
3080 /* This situation can occur if a member template of a template
3081 class is specialized. Then, instantiate_template might return
3082 an instantiation of the specialization, in which case the
3083 DECL_TI_TEMPLATE field will point at the original
3084 specialization. For example:
3086 template <class T> struct S { template <class U> void f(U);
3087 template <> void f(int) {}; };
3088 S<double> sd;
3089 sd.f(3);
3091 Here, TMPL will be template <class U> S<double>::f(U).
3092 And, instantiate template will give us the specialization
3093 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3094 for this will point at template <class T> template <> S<T>::f(int),
3095 so that we can find the definition. For the purposes of
3096 overload resolution, however, we want the original TMPL. */
3098 else
3103 fail:
3106 }
3115 {
3116 return
3121 }
3130 {
3131 return
3135 complain);
3136 }
3138 /* The CANDS are the set of candidates that were considered for
3139 overload resolution. Return the set of viable candidates, or CANDS
3140 if none are viable. If any of the candidates were viable, set
3141 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3142 considered viable only if it is strictly viable. */
3148 {
3154 /* Be strict inside templates, since build_over_call won't actually
3155 do the conversions to get pedwarns. */
3165 {
3169 {
3170 /* Be strict in the presence of a viable candidate. Also if
3171 there are template candidates, so that we get deduction errors
3172 for them instead of silently preferring a bad conversion. */
3175 {
3176 /* Put any spliced near matches back onto the main list so
3177 that we see them if there is no strict match. */
3183 }
3184 }
3187 {
3195 }
3196 else
3198 }
3201 }
3203 static bool
3205 {
3210 }
3212 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3213 words, it is about to become the "this" pointer for a member
3214 function call. Take the address of the object. */
3216 static tree
3218 {
3219 /* In a template, we are only concerned about the type of the
3220 expression, so we can take a shortcut. */
3225 }
3227 /* Returns true iff functions are equivalent. Equivalent functions are
3228 not '==' only if one is a function-local extern function or if
3229 both are extern "C". */
3233 {
3242 }
3244 /* Print information about a candidate being rejected due to INFO. */
3246 static void
3248 {
3253 {
3254 /* Conversion of implicit `this' argument failed. */
3256 /* A bad conversion for 'this' must be discarding cv-quals. */
3259 from);
3260 else
3264 }
3266 {
3271 tf_warning_or_error);
3272 }
3274 /* Conversion of conversion function return value failed. */
3277 else
3280 }
3282 /* Print information about a candidate with WANT parameters and we found
3283 HAVE. */
3285 static void
3287 {
3292 }
3294 /* Print information about one overload candidate CANDIDATE. MSGSTR
3295 is the text to print before the candidate itself.
3297 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3298 to have been run through gettext by the caller. This wart makes
3299 life simpler in print_z_candidates and for the translators. */
3301 static void
3304 {
3311 {
3322 else
3325 }
3332 else
3334 /* Give the user some information about why this candidate failed. */
3336 {
3340 {
3353 "cannot be converted to %qT with a qualification "
3359 "conversion function specialization to %qT is not an "
3364 /* We use template_unification_error_rejection if unification caused
3365 actual non-SFINAE errors, in which case we don't need to repeat
3366 them here. */
3368 {
3372 }
3373 /* Re-run template unification with diagnostics. */
3377 (make_tree_vec
3388 " a constructor taking a single argument of its own "
3393 /* This candidate didn't have any issues or we failed to
3394 handle a particular code. Either way... */
3396 }
3397 }
3398 }
3400 static void
3402 {
3409 /* Remove non-viable deleted candidates. */
3412 {
3417 else
3419 }
3420 /* ...if there are any non-deleted ones. */
3424 /* There may be duplicates in the set of candidates. We put off
3425 checking this condition as long as possible, since we have no way
3426 to eliminate duplicates from a set of functions in less than n^2
3427 time. Now we are about to emit an error message, so it is more
3428 permissible to go slowly. */
3430 {
3432 /* Skip builtin candidates and conversion functions. */
3437 {
3441 else
3443 }
3444 }
3448 }
3450 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3451 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3452 the result of the conversion function to convert it to the final
3453 desired type. Merge the two sequences into a single sequence,
3454 and return the merged sequence. */
3458 {
3464 /* Find the end of the second conversion sequence. */
3466 {
3467 /* The entire sequence is a user-conversion sequence. */
3471 }
3473 /* Replace the identity conversion with the user conversion
3474 sequence. */
3478 }
3480 /* Handle overload resolution for initializing an object of class type from
3481 an initializer list. First we look for a suitable constructor that
3482 takes a std::initializer_list; if we don't find one, we then look for a
3483 non-list constructor.
3485 Parameters are as for add_candidates, except that the arguments are in
3486 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3487 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3489 static void
3496 tsubst_flags_t complain)
3497 {
3502 /* We're looking for a ctor for list-initialization. */
3504 /* And we don't allow narrowing conversions. We also use this flag to
3505 avoid the copy constructor call for copy-list-initialization. */
3508 /* Always use the default constructor if the list is empty (DR 990). */
3511 ;
3512 /* If the class has a list ctor, try passing the list as a single
3513 argument first, but only consider list ctors. */
3515 {
3523 }
3527 /* We aren't looking for list-ctors anymore. */
3529 /* We allow more user-defined conversions within an init-list. */
3535 }
3537 /* Returns the best overload candidate to perform the requested
3538 conversion. This function is used for three the overloading situations
3539 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3540 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3541 per [dcl.init.ref], so we ignore temporary bindings. */
3545 tsubst_flags_t complain)
3546 {
3548 tree fromtype;
3562 /* We represent conversion within a hierarchy using RVALUE_CONV and
3563 BASE_CONV, as specified by [over.best.ics]; these become plain
3564 constructor calls, as specified in [dcl.init]. */
3569 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3570 creating a garbage BASELINK; constructors can't be inherited. */
3574 {
3579 {
3580 /* [class.conv.fct] A conversion function is never used to
3581 convert a (possibly cv-qualified) object to the (possibly
3582 cv-qualified) same object type (or a reference to it), to a
3583 (possibly cv-qualified) base class of that type (or a
3584 reference to it)... */
3585 }
3586 else
3588 }
3595 /* It's OK to bind a temporary for converting constructor arguments, but
3596 not in converting the return value of a conversion operator. */
3602 {
3607 /* We should never try to call the abstract or base constructor
3608 from here. */
3613 {
3614 /* List-initialization. */
3618 }
3619 else
3620 {
3625 }
3628 {
3631 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3632 set, then this is copy-initialization. In that case, "The
3633 result of the call is then used to direct-initialize the
3634 object that is the destination of the copy-initialization."
3635 [dcl.init]
3637 We represent this in the conversion sequence with an
3638 rvalue conversion, which means a constructor call. */
3641 cand->second_conv
3643 }
3644 }
3650 {
3654 /* If we are called to convert to a reference type, we are trying to
3655 find a direct binding, so don't even consider temporaries. If
3656 we don't find a direct binding, the caller will try again to
3657 look for a temporary binding. */
3668 {
3670 conversion *ics
3672 rettype,
3675 complain);
3677 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3678 copy-initialization. In that case, "The result of the
3679 call is then used to direct-initialize the object that is
3680 the destination of the copy-initialization." [dcl.init]
3682 We represent this in the conversion sequence with an
3683 rvalue conversion, which means a constructor call. But
3684 don't add a second rvalue conversion if there's already
3685 one there. Which there really shouldn't be, but it's
3686 harmless since we'd add it here anyway. */
3694 {
3698 }
3701 {
3702 /* 13.3.1.5: For direct-initialization, those explicit
3703 conversion functions that are not hidden within S and
3704 yield type T or a type that can be converted to type T
3705 with a qualification conversion (4.4) are also candidate
3706 functions. */
3707 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3708 I've raised this issue with the committee. --jason 9/2011 */
3711 }
3713 {
3715 cand->reason
3718 }
3721 {
3722 /* 13.3.3.1.2: If the user-defined conversion is specified by
3723 a specialization of a conversion function template, the
3724 second standard conversion sequence shall have exact match
3725 rank. */
3728 }
3729 }
3730 }
3734 {
3738 }
3742 {
3744 {
3748 }
3755 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3756 ambiguous conversion is no worse than another user-defined
3757 conversion. */
3760 }
3762 tree convtype;
3766 /* DR 5: [in the first step of copy-initialization]...if the function
3767 is a constructor, the call initializes a temporary of the
3768 cv-unqualified version of the destination type. */
3770 else
3772 /* Build the user conversion sequence. */
3773 conv = build_conv
3775 convtype,
3781 /* Remember that this was a list-initialization. */
3785 /* Combine it with the second conversion sequence. */
3790 }
3792 /* Wrapper for above. */
3794 tree
3796 tsubst_flags_t complain)
3797 {
3799 tree ret;
3805 {
3808 else
3809 {
3812 }
3813 }
3814 else
3819 }
3821 /* Subroutine of convert_nontype_argument.
3823 EXPR is an argument for a template non-type parameter of integral or
3824 enumeration type. Do any necessary conversions (that are permitted for
3825 non-type arguments) to convert it to the parameter type.
3827 If conversion is successful, returns the converted expression;
3828 otherwise, returns error_mark_node. */
3830 tree
3832 {
3835 tree t;
3843 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3850 /* for a non-type template-parameter of integral or
3851 enumeration type, integral promotions (4.5) and integral
3852 conversions (4.7) are applied. */
3853 /* It should be sufficient to check the outermost conversion step, since
3854 there are no qualification conversions to integer type. */
3857 {
3858 /* A conversion function is OK. If it isn't constexpr, we'll
3859 complain later that the argument isn't constant. */
3861 /* The lvalue-to-rvalue conversion is OK. */
3874 /* and fall through. */
3879 }
3883 else
3886 /* Free all the conversions we allocated. */
3890 }
3892 /* Do any initial processing on the arguments to a function call. */
3896 {
3898 tree arg;
3901 {
3905 {
3909 }
3912 }
3914 }
3916 /* Perform overload resolution on FN, which is called with the ARGS.
3918 Return the candidate function selected by overload resolution, or
3919 NULL if the event that overload resolution failed. In the case
3920 that overload resolution fails, *CANDIDATES will be the set of
3921 candidates considered, and ANY_VIABLE_P will be set to true or
3922 false to indicate whether or not any of the candidates were
3923 viable.
3925 The ARGS should already have gone through RESOLVE_ARGS before this
3926 function is called. */
3933 {
3935 tree explicit_targs;
3946 /* Check FN. */
3953 {
3957 }
3959 /* Add the various candidate functions. */
3964 LOOKUP_NORMAL,
3970 else
3975 }
3977 /* Print an error message about being unable to build a call to FN with
3978 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
3979 be located; CANDIDATES is a possibly empty list of such
3980 functions. */
3982 static void
3985 {
3992 else
3997 }
3999 /* Return an expression for a call to FN (a namespace-scope function,
4000 or a static member function) with the ARGS. This may change
4001 ARGS. */
4003 tree
4005 tsubst_flags_t complain)
4006 {
4010 tree result;
4013 {
4017 }
4022 /* If this function was found without using argument dependent
4023 lookup, then we want to ignore any undeclared friend
4024 functions. */
4026 {
4031 {
4035 }
4036 }
4038 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4042 complain);
4045 {
4047 {
4054 }
4056 }
4057 else
4058 {
4060 /* If fn is template_id_expr, the call has explicit template arguments
4061 (e.g. func<int>(5)), communicate this info to build_over_call
4062 through flags so that later we can use it to decide whether to warn
4063 about peculiar null pointer conversion. */
4067 }
4069 /* Free all the conversions we allocated. */
4073 }
4075 /* Build a call to a global operator new. FNNAME is the name of the
4076 operator (either "operator new" or "operator new[]") and ARGS are
4077 the arguments provided. This may change ARGS. *SIZE points to the
4078 total number of bytes required by the allocation, and is updated if
4079 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4080 be used. If this function determines that no cookie should be
4081 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4082 is not NULL_TREE, it is evaluated before calculating the final
4083 array size, and if it fails, the array size is replaced with
4084 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4085 is non-NULL, it will be set, upon return, to the allocation
4086 function called. */
4088 tree
4092 {
4094 tree fns;
4101 /* Set to (size_t)-1 if the size check fails. */
4103 {
4109 }
4115 /* Based on:
4117 [expr.new]
4119 If this lookup fails to find the name, or if the allocated type
4120 is not a class type, the allocation function's name is looked
4121 up in the global scope.
4123 we disregard block-scope declarations of "operator new". */
4126 /* Figure out what function is being called. */
4128 complain);
4130 /* If no suitable function could be found, issue an error message
4131 and give up. */
4133 {
4137 }
4139 /* If a cookie is required, add some extra space. Whether
4140 or not a cookie is required cannot be determined until
4141 after we know which function was called. */
4143 {
4145 tree arg_types;
4148 /* Skip the size_t parameter. */
4150 /* Check the remaining parameters (if any). */
4154 ptr_type_node))
4156 /* If we need a cookie, adjust the number of bytes allocated. */
4158 {
4159 /* Update the total size. */
4161 /* Set to (size_t)-1 if the size check fails. */
4165 /* Update the argument list to reflect the adjusted size. */
4167 }
4168 else
4170 }
4172 /* Tell our caller which function we decided to call. */
4176 /* Build the CALL_EXPR. */
4178 }
4180 /* Build a new call to operator(). This may change ARGS. */
4182 static tree
4184 {
4198 {
4200 /* It's no good looking for an overloaded operator() on a
4201 pointer-to-member-function. */
4202 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4204 }
4207 {
4211 }
4212 else
4216 {
4220 }
4222 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4226 {
4234 }
4239 {
4248 {
4255 add_template_conv_candidate
4259 else
4263 }
4264 }
4266 /* Be strict here because if we choose a bad conversion candidate, the
4267 errors we get won't mention the call context. */
4270 {
4272 {
4276 }
4278 }
4279 else
4280 {
4283 {
4285 {
4289 }
4291 }
4292 /* Since cand->fn will be a type, not a function, for a conversion
4293 function, we must be careful not to unconditionally look at
4294 DECL_NAME here. */
4298 else
4299 {
4301 complain);
4304 }
4305 }
4307 /* Free all the conversions we allocated. */
4311 }
4313 /* Wrapper for above. */
4315 tree
4317 {
4318 tree ret;
4323 }
4325 /* Called by op_error to prepare format strings suitable for the error
4326 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4327 and a suffix (controlled by NTYPES). */
4331 {
4341 else
4345 }
4347 static void
4350 {
4355 else
4359 {
4365 else
4377 else
4387 else
4398 else
4408 else
4413 else
4417 else
4422 }
4423 }
4425 /* Return the implicit conversion sequence that could be used to
4426 convert E1 to E2 in [expr.cond]. */
4430 {
4436 /* [expr.cond]
4438 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4439 implicitly converted (clause _conv_) to the type "lvalue reference to
4440 T2", subject to the constraint that in the conversion the
4441 reference must bind directly (_dcl.init.ref_) to an lvalue.
4443 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4444 implicitly converted to the type "rvalue reference to T2", subject to
4445 the constraint that the reference must bind directly. */
4447 {
4450 t1,
4451 e1,
4453 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4455 complain);
4458 }
4460 /* If E2 is a prvalue or if neither of the conversions above can be done
4461 and at least one of the operands has (possibly cv-qualified) class
4462 type: */
4466 /* [expr.cond]
4468 If E1 and E2 have class type, and the underlying class types are
4469 the same or one is a base class of the other: E1 can be converted
4470 to match E2 if the class of T2 is the same type as, or a base
4471 class of, the class of T1, and the cv-qualification of T2 is the
4472 same cv-qualification as, or a greater cv-qualification than, the
4473 cv-qualification of T1. If the conversion is applied, E1 is
4474 changed to an rvalue of type T2 that still refers to the original
4475 source class object (or the appropriate subobject thereof). */
4478 {
4480 {
4485 else
4488 }
4489 else
4491 }
4492 else
4493 /* [expr.cond]
4495 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4496 converted to the type that expression E2 would have if E2 were
4497 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4500 }
4502 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4503 arguments to the conditional expression. */
4505 static tree
4507 tsubst_flags_t complain)
4508 {
4509 tree arg2_type;
4510 tree arg3_type;
4519 /* As a G++ extension, the second argument to the conditional can be
4520 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4521 c'.) If the second operand is omitted, make sure it is
4522 calculated only once. */
4524 {
4529 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4532 else
4534 }
4536 /* If something has already gone wrong, just pass that fact up the
4537 tree. */
4547 {
4552 /* force_rvalue can return error_mark on valid arguments. */
4564 {
4565 /* Rely on the error messages of the scalar version. */
4574 {
4582 }
4586 /* We could pass complain & tf_warning to unsafe_conversion_p,
4587 but the warnings (like Wsign-conversion) have already been
4588 given by the scalar build_conditional_expr_1. We still check
4589 unsafe_conversion_p to forbid truncating long long -> float. */
4591 {
4596 }
4598 {
4603 }
4613 }
4617 {
4623 {
4627 {
4633 }
4635 {
4641 }
4644 }
4645 }
4651 {
4654 "incompatible vector types in conditional expression: "
4658 }
4664 }
4666 /* [expr.cond]
4668 The first expression is implicitly converted to bool (clause
4669 _conv_). */
4671 LOOKUP_NORMAL);
4675 /* [expr.cond]
4677 If either the second or the third operand has type (possibly
4678 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4679 array-to-pointer (_conv.array_), and function-to-pointer
4680 (_conv.func_) standard conversions are performed on the second
4681 and third operands. */
4685 {
4686 /* Do the conversions. We don't these for `void' type arguments
4687 since it can't have any effect and since decay_conversion
4688 does not handle that case gracefully. */
4696 /* [expr.cond]
4698 One of the following shall hold:
4700 --The second or the third operand (but not both) is a
4701 throw-expression (_except.throw_); the result is of the
4702 type of the other and is an rvalue.
4704 --Both the second and the third operands have type void; the
4705 result is of type void and is an rvalue.
4707 We must avoid calling force_rvalue for expressions of type
4708 "void" because it will complain that their value is being
4709 used. */
4712 {
4714 {
4718 }
4721 }
4724 {
4726 {
4730 }
4733 }
4736 else
4737 {
4739 {
4742 "second operand to the conditional operator "
4743 "is of type %<void%>, but the third operand is "
4745 else
4747 "third operand to the conditional operator "
4748 "is of type %<void%>, but the second operand is "
4750 }
4752 }
4756 }
4757 /* [expr.cond]
4759 Otherwise, if the second and third operand have different types,
4760 and either has (possibly cv-qualified) class type, or if both are
4761 glvalues of the same value category and the same type except for
4762 cv-qualification, an attempt is made to convert each of those operands
4763 to the type of the other. */
4767 arg3_type)
4771 {
4776 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4782 /* [expr.cond]
4784 If both can be converted, or one can be converted but the
4785 conversion is ambiguous, the program is ill-formed. If
4786 neither can be converted, the operands are left unchanged and
4787 further checking is performed as described below. If exactly
4788 one conversion is possible, that conversion is applied to the
4789 chosen operand and the converted operand is used in place of
4790 the original operand for the remainder of this section. */
4795 {
4797 {
4804 else
4806 }
4808 }
4810 {
4814 /* Even if CONV2 is a valid conversion, the result of the
4815 conversion may be invalid. For example, if ARG3 has type
4816 "volatile X", and X does not have a copy constructor
4817 accepting a "volatile X&", then even if ARG2 can be
4818 converted to X, the conversion will fail. */
4822 }
4824 {
4831 }
4833 /* Free all the conversions we allocated. */
4839 /* If, after the conversion, both operands have class type,
4840 treat the cv-qualification of both operands as if it were the
4841 union of the cv-qualification of the operands.
4843 The standard is not clear about what to do in this
4844 circumstance. For example, if the first operand has type
4845 "const X" and the second operand has a user-defined
4846 conversion to "volatile X", what is the type of the second
4847 operand after this step? Making it be "const X" (matching
4848 the first operand) seems wrong, as that discards the
4849 qualification without actually performing a copy. Leaving it
4850 as "volatile X" seems wrong as that will result in the
4851 conditional expression failing altogether, even though,
4852 according to this step, the one operand could be converted to
4853 the type of the other. */
4861 }
4863 /* [expr.cond]
4865 If the second and third operands are glvalues of the same value
4866 category and have the same type, the result is of that type and
4867 value category. */
4871 {
4876 }
4878 /* [expr.cond]
4880 Otherwise, the result is an rvalue. If the second and third
4881 operand do not have the same type, and either has (possibly
4882 cv-qualified) class type, overload resolution is used to
4883 determine the conversions (if any) to be applied to the operands
4884 (_over.match.oper_, _over.built_). */
4888 {
4893 /* Rearrange the arguments so that add_builtin_candidate only has
4894 to know about two args. In build_builtin_candidate, the
4895 arguments are unscrambled. */
4900 COND_EXPR,
4901 NOP_EXPR,
4903 args,
4906 /* [expr.cond]
4908 If the overload resolution fails, the program is
4909 ill-formed. */
4912 {
4917 }
4920 {
4922 {
4925 }
4927 }
4929 /* [expr.cond]
4931 Otherwise, the conversions thus determined are applied, and
4932 the converted operands are used in place of the original
4933 operands for the remainder of this section. */
4942 }
4944 /* [expr.cond]
4946 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4947 and function-to-pointer (_conv.func_) standard conversions are
4948 performed on the second and third operands.
4950 We need to force the lvalue-to-rvalue conversion here for class types,
4951 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4952 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4953 regions. */
4966 /* [expr.cond]
4968 After those conversions, one of the following shall hold:
4970 --The second and third operands have the same type; the result is of
4971 that type. */
4974 /* [expr.cond]
4976 --The second and third operands have arithmetic or enumeration
4977 type; the usual arithmetic conversions are performed to bring
4978 them to a common type, and the result is of that type. */
4983 {
4984 /* In this case, there is always a common type. */
4986 arg3_type);
4989 "implicit conversion from %qT to %qT to "
4991 loc);
4995 {
4999 /* Two enumerators from the same enumeration can have different
5005 }
5012 {
5016 }
5020 }
5021 /* [expr.cond]
5023 --The second and third operands have pointer type, or one has
5024 pointer type and the other is a null pointer constant; pointer
5025 conversions (_conv.ptr_) and qualification conversions
5026 (_conv.qual_) are performed to bring them to their composite
5027 pointer type (_expr.rel_). The result is of the composite
5028 pointer type.
5030 --The second and third operands have pointer to member type, or
5031 one has pointer to member type and the other is a null pointer
5032 constant; pointer to member conversions (_conv.mem_) and
5033 qualification conversions (_conv.qual_) are performed to bring
5034 them to a common type, whose cv-qualification shall match the
5035 cv-qualification of either the second or the third operand.
5036 The result is of the common type. */
5044 {
5047 complain);
5052 }
5055 {
5060 }
5065 valid_operands:
5068 /* Avoid folding within decltype (c++/42013) and noexcept. */
5071 /* We can't use result_type below, as fold might have returned a
5072 throw_expr. */
5075 {
5076 /* Expand both sides into the same slot, hopefully the target of
5077 the ?: expression. We used to check for TARGET_EXPRs here,
5078 but now we sometimes wrap them in NOP_EXPRs so the test would
5079 fail. */
5082 /* If this expression is an rvalue, but might be mistaken for an
5083 lvalue, we must add a NON_LVALUE_EXPR. */
5085 }
5086 else
5090 }
5092 /* Wrapper for above. */
5094 tree
5096 tsubst_flags_t complain)
5097 {
5098 tree ret;
5103 }
5105 /* OPERAND is an operand to an expression. Perform necessary steps
5106 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5107 returned. */
5109 static tree
5111 {
5113 {
5116 /* Make sure the template type is instantiated now. */
5118 }
5121 }
5123 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5124 OVERLOAD) to the CANDIDATES, returning an updated list of
5125 CANDIDATES. The ARGS are the arguments provided to the call;
5126 if FIRST_ARG is non-null it is the implicit object argument,
5127 otherwise the first element of ARGS is used if needed. The
5128 EXPLICIT_TARGS are explicit template arguments provided.
5129 TEMPLATE_ONLY is true if only template functions should be
5130 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5131 add_function_candidate. */
5133 static void
5135 tree return_type,
5140 tsubst_flags_t complain)
5141 {
5142 tree ctype;
5146 unification_kind_t strict;
5147 tree fn;
5152 /* Precalculate special handling of constructors and conversion ops. */
5155 {
5159 /* We're doing return_type(x). */
5161 else
5162 /* We're doing x.operator return_type(). */
5164 /* [over.match.funcs] For conversion functions, the function
5165 is considered to be a member of the class of the implicit
5166 object argument for the purpose of defining the type of
5167 the implicit object parameter. */
5169 }
5170 else
5171 {
5173 {
5175 /* For list-initialization we consider explicit constructors
5176 and complain if one is chosen. */
5177 check_converting
5180 }
5181 else
5182 {
5185 }
5188 }
5192 else
5193 /* Delay creating the implicit this parameter until it is needed. */
5197 {
5198 tree fn_first_arg;
5208 /* Figure out which set of arguments to use. */
5210 {
5211 /* If this function is a non-static member and we didn't get an
5212 implicit object argument, move it out of args. */
5214 {
5216 tree arg;
5223 }
5227 }
5228 else
5229 {
5230 /* Otherwise, just use the list of arguments provided. */
5233 }
5237 fn,
5238 ctype,
5239 explicit_targs,
5240 fn_first_arg,
5241 fn_args,
5242 return_type,
5243 access_path,
5244 conversion_path,
5245 flags,
5246 strict,
5247 complain);
5250 fn,
5251 ctype,
5252 fn_first_arg,
5253 fn_args,
5254 access_path,
5255 conversion_path,
5256 flags,
5257 complain);
5258 }
5259 }
5261 static tree
5264 {
5267 tree fnname;
5285 {
5289 }
5290 else
5297 {
5302 /* Use build_op_new_call and build_op_delete_call instead. */
5306 /* Use build_op_call instead. */
5313 /* These are saved for the sake of warn_logical_operator. */
5323 /* These are saved for the sake of maybe_warn_bool_compare. */
5328 /* =, ->, [], () must be non-static member functions. */
5339 }
5345 /* Use build_conditional_expr instead. */
5361 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5364 /* Add namespace-scope operators to the list of functions to
5365 consider. */
5377 /* Add class-member operators to the candidate set. */
5379 {
5380 tree fns;
5384 {
5387 }
5395 }
5396 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5397 only non-member functions that have type T1 or reference to
5398 cv-qualified-opt T1 for the first argument, if the first argument
5399 has an enumeration type, or T2 or reference to cv-qualified-opt
5400 T2 for the second argument, if the the second argument has an
5401 enumeration type. Filter out those that don't match. */
5403 {
5407 {
5417 {
5423 && (same_type_ignoring_top_level_qualifiers_p
5428 }
5430 /* No argument has an appropriate type, so remove this
5431 candidate function from the list. */
5433 {
5436 }
5437 }
5438 }
5444 {
5447 /* For these, the built-in candidates set is empty
5448 [over.match.oper]/3. We don't want non-strict matches
5449 because exact matches are always possible with built-in
5450 operators. The built-in candidate set for COMPONENT_REF
5451 would be empty too, but since there are no such built-in
5452 operators, we accept non-strict matches for them. */
5459 }
5463 {
5465 {
5468 /* Don't try anything fancy if we're not allowed to produce
5469 errors. */
5473 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5474 distinguish between prefix and postfix ++ and
5475 operator++() was used for both, so we allow this with
5476 -fpermissive. */
5477 else
5478 {
5484 }
5491 else
5497 /* The caller will deal with these. */
5507 {
5508 /* If one of the arguments of the operator represents
5509 an invalid use of member function pointer, try to report
5510 a meaningful error ... */
5515 else
5516 {
5517 /* ... Otherwise, report the more generic
5518 "no matching operator found" error */
5521 }
5522 }
5525 }
5526 }
5527 else
5528 {
5531 {
5533 {
5536 }
5538 }
5540 {
5546 else
5548 }
5549 else
5550 {
5551 /* Give any warnings we noticed during overload resolution. */
5553 {
5557 }
5559 /* Check for comparison of different enum types. */
5561 {
5573 {
5577 }
5581 }
5583 /* We need to strip any leading REF_BIND so that bitfields
5584 don't cause errors. This should not remove any important
5585 conversions, because builtins don't apply to class
5586 objects directly. */
5593 {
5597 else
5600 /* We need to call warn_logical_operator before
5601 converting arg2 to a boolean_type, but after
5602 decaying an enumerator to its value. */
5609 }
5611 {
5616 }
5618 }
5619 }
5621 user_defined_result_ready:
5623 /* Free all the conversions we allocated. */
5629 builtin:
5631 {
5645 /* Fall through. */
5656 /* Fall through. */
5689 complain),
5692 /* The caller will deal with these. */
5700 }
5702 }
5704 /* Wrapper for above. */
5706 tree
5710 {
5711 tree ret;
5717 }
5719 /* Returns true if FN has two parameters, of which the second has type
5720 size_t. */
5722 static bool
5724 {
5729 }
5731 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5732 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5734 bool
5736 {
5737 /* A template instance is never a usual deallocation function,
5738 regardless of its signature. */
5743 /* If a class T has a member deallocation function named operator delete
5744 with exactly one parameter, then that function is a usual
5745 (non-placement) deallocation function. If class T does not declare
5746 such an operator delete but does declare a member deallocation
5747 function named operator delete with exactly two parameters, the second
5748 of which has type std::size_t (18.2), then this function is a usual
5749 deallocation function. */
5756 }
5758 /* Build a call to operator delete. This has to be handled very specially,
5759 because the restrictions on what signatures match are different from all
5760 other call instances. For a normal delete, only a delete taking (void *)
5761 or (void *, size_t) is accepted. For a placement delete, only an exact
5762 match with the placement new is accepted.
5764 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5765 ADDR is the pointer to be deleted.
5766 SIZE is the size of the memory block to be deleted.
5767 GLOBAL_P is true if the delete-expression should not consider
5768 class-specific delete operators.
5769 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5771 If this call to "operator delete" is being generated as part to
5772 deallocate memory allocated via a new-expression (as per [expr.new]
5773 which requires that if the initialization throws an exception then
5774 we call a deallocation function), then ALLOC_FN is the allocation
5775 function. */
5777 tree
5781 {
5795 /* In [class.free]
5797 If the result of the lookup is ambiguous or inaccessible, or if
5798 the lookup selects a placement deallocation function, the
5799 program is ill-formed.
5801 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5802 {
5806 }
5807 else
5813 /* Strip const and volatile from addr. */
5817 {
5818 /* "A declaration of a placement deallocation function matches the
5819 declaration of a placement allocation function if it has the same
5820 number of parameters and, after parameter transformations (8.3.5),
5821 all parameter types except the first are identical."
5823 So we build up the function type we want and ask instantiate_type
5824 to get it for us. */
5836 /* "If the lookup finds the two-parameter form of a usual deallocation
5837 function (3.7.4.2) and that function, considered as a placement
5838 deallocation function, would have been selected as a match for the
5839 allocation function, the program is ill-formed." */
5841 {
5849 /* But if the class has an operator delete (void *), then that is
5850 the usual deallocation function, so we shouldn't complain
5851 about using the operator delete (void *, size_t). */
5855 {
5860 }
5861 /* Before C++14 a two-parameter global deallocation function is
5862 always a placement deallocation function, but warn if
5863 -Wc++14-compat. */
5865 {
5870 }
5873 {
5875 {
5876 /* Only mention C++14 for namespace-scope delete. */
5879 else
5882 }
5883 }
5884 else
5886 ok:;
5887 }
5888 }
5889 else
5890 /* "Any non-placement deallocation function matches a non-placement
5891 allocation function. If the lookup finds a single matching
5892 deallocation function, that function will be called; otherwise, no
5893 deallocation function will be called." */
5896 {
5899 {
5901 /* "If a class T has a member deallocation function named
5902 operator delete with exactly one parameter, then that
5903 function is a usual (non-placement) deallocation
5904 function. If class T does not declare such an operator
5905 delete but does declare a member deallocation function named
5906 operator delete with exactly two parameters, the second of
5907 which has type std::size_t (18.2), then this function is a
5908 usual deallocation function."
5910 So in a class (void*) beats (void*, size_t). */
5912 {
5915 }
5916 /* At global scope (in C++14 and above) the rules are different:
5918 If deallocation function lookup finds both a usual
5919 deallocation function with only a pointer parameter and a
5920 usual deallocation function with both a pointer parameter
5921 and a size parameter, the function to be called is selected
5922 as follows:
5924 * If the type is complete and if, for the second alternative
5925 (delete array) only, the operand is a pointer to a class
5926 type with a non-trivial destructor or a (possibly
5927 multi-dimensional) array thereof, the function with two
5928 parameters is selected.
5930 * Otherwise, it is unspecified which of the two deallocation
5931 functions is selected. */
5932 else
5933 {
5937 /* We need a cookie to determine the array size. */
5942 }
5943 }
5944 }
5946 /* If we have a matching function, call it. */
5948 {
5951 /* If the FN is a member function, make sure that it is
5952 accessible. */
5955 complain);
5957 /* Core issue 901: It's ok to new a type with deleted delete. */
5962 {
5963 /* The placement args might not be suitable for overload
5964 resolution at this point, so build the call directly. */
5974 }
5975 else
5976 {
5977 tree ret;
5985 }
5986 }
5988 /* [expr.new]
5990 If no unambiguous matching deallocation function can be found,
5991 propagating the exception does not cause the object's memory to
5992 be freed. */
5994 {
5998 alloc_fn);
6000 }
6006 }
6008 /* If the current scope isn't allowed to access DECL along
6009 BASETYPE_PATH, give an error. The most derived class in
6010 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6011 the declaration to use in the error diagnostic. */
6013 bool
6015 tsubst_flags_t complain)
6016 {
6020 {
6022 {
6024 {
6028 }
6030 {
6034 }
6035 else
6036 {
6039 }
6040 }
6042 }
6045 }
6047 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6048 bitwise or of LOOKUP_* values. If any errors are warnings are
6049 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6050 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6051 to NULL. */
6053 static tree
6056 {
6069 else
6072 }
6074 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6075 EXPR is implicitly converted to type TOTYPE.
6076 FN and ARGNUM are used for diagnostics. */
6078 static void
6080 {
6081 /* Issue warnings about peculiar, but valid, uses of NULL. */
6084 {
6085 source_location loc =
6092 else
6095 }
6097 /* Issue warnings if "false" is converted to a NULL pointer */
6100 {
6103 "converting %<false%> to pointer type for argument %P "
6105 else
6108 }
6109 }
6111 /* We gave a diagnostic during a conversion. If this was in the second
6112 standard conversion sequence of a user-defined conversion sequence, say
6113 which user-defined conversion. */
6115 static void
6117 {
6121 {
6125 }
6126 }
6128 /* Perform the conversions in CONVS on the expression EXPR. FN and
6129 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6130 indicates the `this' argument of a method. INNER is nonzero when
6131 being called to continue a conversion chain. It is negative when a
6132 reference binding will be applied, positive otherwise. If
6133 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6134 conversions will be emitted if appropriate. If C_CAST_P is true,
6135 this conversion is coming from a C-style cast; in that case,
6136 conversions to inaccessible bases are permitted. */
6138 static tree
6142 {
6144 diagnostic_t diag_kind;
6160 {
6164 /* Give a helpful error if this is bad because of excess braces. */
6169 {
6175 }
6177 /* Give a helpful error if this is bad because a conversion to bool
6178 from std::nullptr_t requires direct-initialization. */
6186 {
6188 {
6191 totype);
6197 complain);
6201 complain);
6202 else
6208 }
6210 {
6214 complain);
6216 }
6221 complain);
6224 }
6233 }
6239 {
6241 {
6246 /* If we're initializing from {}, it's value-initialization. Note
6247 that under the resolution of core 1630, value-initialization can
6248 use explicit constructors. */
6252 {
6257 {
6260 }
6262 }
6264 /* When converting from an init list we consider explicit
6265 constructors, but actually trying to call one is an error. */
6267 /* Unless this is for direct-list-initialization. */
6269 {
6274 }
6278 /* Set user_conv_p on the argument conversions, so rvalue/base
6279 handling knows not to allow any more UDCs. */
6285 /* If this is a constructor or a function returning an aggr type,
6286 we need to build up a TARGET_EXPR. */
6288 {
6291 /* Remember that this was list-initialization. */
6294 }
6297 }
6300 {
6306 else
6308 }
6313 /* Convert a constant to its underlying value, unless we are
6314 about to bind it to a reference, in which case we need to
6315 leave it as an lvalue. */
6317 {
6320 /* If __null has been converted to an integer type, we do not
6321 want to warn about uses of EXPR as an integer, rather than
6322 as a pointer. */
6324 }
6327 /* We leave bad_p off ck_ambig because overload resolution considers
6328 it valid, it just fails when we try to perform it. So we need to
6329 check complain here, too. */
6331 {
6332 /* Call build_user_type_conversion again for the error. */
6334 complain);
6338 }
6342 {
6343 /* Conversion to std::initializer_list<T>. */
6351 /* Convert all the elements. */
6353 {
6364 }
6365 /* Build up the array. */
6366 elttype = cp_build_qualified_type
6370 /* Take the address explicitly rather than via decay_conversion
6371 to avoid the error about taking the address of a temporary. */
6377 /* Build up the initializer_list object. */
6385 }
6389 {
6398 }
6401 complain);
6408 };
6413 c_cast_p,
6414 complain);
6419 {
6427 /* Else fall through. */
6430 {
6431 /* We are going to bind a reference directly to a base-class
6432 subobject of EXPR. */
6433 /* Build an expression for `*((base*) &expr)'. */
6437 }
6439 /* Copy-initialization where the cv-unqualified version of the source
6440 type is the same class as, or a derived class of, the class of the
6441 destination [is treated as direct-initialization]. [dcl.init] */
6444 /* This conversion is being done in the context of a user-defined
6445 conversion (i.e. the second step of copy-initialization), so
6446 don't allow any more. */
6452 /* Copy-list-initialization doesn't actually involve a copy. */
6456 {
6461 }
6466 {
6470 {
6483 else
6490 }
6492 /* If necessary, create a temporary.
6494 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6495 that need temporaries, even when their types are reference
6496 compatible with the type of reference being bound, so the
6497 upcoming call to cp_build_addr_expr doesn't fail. */
6501 {
6502 /* Otherwise, a temporary of type "cv1 T1" is created and
6503 initialized from the initializer expression using the rules
6504 for a non-reference copy-initialization (8.5). */
6513 {
6514 /* If the reference is volatile or non-const, we
6515 cannot create a temporary. */
6522 else
6526 }
6527 /* If the source is a packed field, and we must use a copy
6528 constructor, then building the target expr will require
6529 binding the field to the reference parameter to the
6530 copy constructor, and we'll end up with an infinite
6531 loop. If we can use a bitwise copy, then we'll be
6532 OK. */
6536 {
6540 }
6542 {
6545 }
6547 }
6549 /* Take the address of the thing to which we will bind the
6550 reference. */
6555 /* Convert it to a pointer to the type referred to by the
6556 reference. This will adjust the pointer if a derived to
6557 base conversion is being performed. */
6560 /* Convert the pointer to the desired reference type. */
6562 }
6568 /* Warn about deprecated conversion if appropriate. */
6584 }
6592 else
6596 }
6598 /* ARG is being passed to a varargs function. Perform any conversions
6599 required. Return the converted value. */
6601 tree
6603 {
6604 tree arg_type;
6607 /* [expr.call]
6609 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6610 standard conversions are performed. */
6613 /* [expr.call]
6615 If the argument has integral or enumeration type that is subject
6616 to the integral promotions (_conv.prom_), or a floating point
6617 type that is subject to the floating point promotion
6618 (_conv.fpprom_), the value of the argument is converted to the
6619 promoted type before the call. */
6624 {
6628 "implicit conversion from %qT to %qT when passing "
6632 }
6636 {
6638 {
6640 complain);
6650 }
6651 else
6653 }
6659 /* In a template (or ill-formed code), we can have an incomplete type
6660 even after require_complete_type_sfinae, in which case we don't know
6661 whether it has trivial copy or not. */
6663 {
6664 /* Build up a real lvalue-to-rvalue conversion in case the
6665 copy constructor is trivial but not callable. */
6669 /* [expr.call] 5.2.2/7:
6670 Passing a potentially-evaluated argument of class type (Clause 9)
6671 with a non-trivial copy constructor or a non-trivial destructor
6672 with no corresponding parameter is conditionally-supported, with
6673 implementation-defined semantics.
6675 We support it as pass-by-invisible-reference, just like a normal
6676 value parameter.
6678 If the call appears in the context of a sizeof expression,
6679 it is not potentially-evaluated. */
6683 {
6686 "passing objects of non-trivially-copyable "
6688 arg_type);
6690 }
6691 }
6694 }
6696 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6698 tree
6700 {
6702 {
6706 }
6716 {
6719 }
6723 {
6724 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6725 it as pass by invisible reference. */
6727 "receiving objects of non-trivially-copyable type %q#T "
6733 }
6736 }
6738 /* TYPE has been given to va_arg. Apply the default conversions which
6739 would have happened when passed via ellipsis. Return the promoted
6740 type, or the passed type if there is no change. */
6742 tree
6744 {
6745 tree promote;
6747 /* Perform the array-to-pointer and function-to-pointer
6748 conversions. */
6756 }
6758 /* ARG is a default argument expression being passed to a parameter of
6759 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6760 zero-based argument number. Do any required conversions. Return
6761 the converted value. */
6764 void
6768 void
6772 tree
6774 tsubst_flags_t complain)
6775 {
6777 tree t;
6779 /* See through clones. */
6782 /* Detect recursion. */
6785 {
6789 }
6791 /* If the ARG is an unparsed default argument expression, the
6792 conversion cannot be performed. */
6794 {
6799 }
6806 /* Due to:
6808 [dcl.fct.default]
6810 The names in the expression are bound, and the semantic
6811 constraints are checked, at the point where the default
6812 expressions appears.
6814 we must not perform access checks here. */
6816 /* We must make a copy of ARG, in case subsequent processing
6817 alters any part of it. */
6821 complain);
6828 }
6830 /* Returns the type which will really be used for passing an argument of
6831 type TYPE. */
6833 tree
6835 {
6836 /* Pass classes with copy ctors by invisible reference. */
6838 {
6840 /* There are no other pointers to this temporary. */
6842 }
6850 }
6852 /* Actually perform the appropriate conversion. */
6854 tree
6856 {
6857 tree bitfield_type;
6859 /* If VAL is a bitfield, then -- since it has already been converted
6860 to TYPE -- it cannot have a precision greater than TYPE.
6862 If it has a smaller precision, we must widen it here. For
6863 example, passing "int f:3;" to a function expecting an "int" will
6864 not result in any conversion before this point.
6866 If the precision is the same we must not risk widening. For
6867 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6868 often have type "int", even though the C++ type for the field is
6869 "long long". If the value is being passed to a function
6870 expecting an "int", then no conversions will be required. But,
6871 if we call convert_bitfield_to_declared_type, the bitfield will
6872 be converted to "long long". */
6879 ;
6880 /* Pass classes with copy ctors by invisible reference. */
6890 {
6899 }
6901 }
6903 /* Returns true iff FN is a function with magic varargs, i.e. ones for
6904 which no conversions at all should be done. This is true for some
6905 builtins which don't act like normal functions. */
6907 bool
6909 {
6915 {
6925 }
6928 }
6930 /* Returns the decl of the dispatcher function if FN is a function version. */
6932 tree
6934 {
6944 {
6948 }
6953 }
6955 /* fn is a function version dispatcher that is marked used. Mark all the
6956 semantically identical function versions it will dispatch as used. */
6958 void
6960 {
6977 /* All semantically identical versions are chained. Traverse and mark each
6978 one of them as used. */
6981 {
6984 }
6985 }
6987 /* Build a call to "the copy constructor" for the type of A, even if it
6988 wouldn't be selected by normal overload resolution. Used for
6989 diagnostics. */
6991 static tree
6993 {
7004 }
7006 /* Subroutine of the various build_*_call functions. Overload resolution
7007 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7008 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7009 bitmask of various LOOKUP_* flags which apply to the call itself. */
7011 static tree
7013 {
7021 tree val;
7030 /* In a template, there is no need to perform all of the work that
7031 is normally done. We are only interested in the type of the call
7032 expression, i.e., the return type of the function. Any semantic
7033 errors will be deferred until the template is instantiated. */
7035 {
7037 tree return_type;
7045 else
7046 {
7049 tree arg;
7057 }
7067 }
7069 /* Give any warnings we noticed during overload resolution. */
7071 {
7075 }
7077 /* Make =delete work with SFINAE. */
7082 {
7083 tree access_fn;
7084 /* If FN is a template function, two cases must be considered.
7085 For example:
7087 struct A {
7088 protected:
7089 template <class T> void f();
7090 };
7091 template <class T> struct B {
7092 protected:
7093 void g();
7094 };
7095 struct C : A, B<int> {
7096 using A::f; // #1
7097 using B<int>::g; // #2
7098 };
7100 In case #1 where `A::f' is a member template, DECL_ACCESS is
7101 recorded in the primary template but not in its specialization.
7102 We check access of FN using its primary template.
7104 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7105 because it is a member of class template B, DECL_ACCESS is
7106 recorded in the specialization `B<int>::g'. We cannot use its
7107 primary template because `B<T>::g' and `B<int>::g' may have
7108 different access. */
7112 else
7117 }
7119 /* If we're checking for implicit delete, don't bother with argument
7120 conversions. */
7122 {
7124 {
7128 }
7132 /* Reject bad conversions now. */
7134 /* else continue to get conversion error. */
7135 }
7137 /* N3276 magic doesn't apply to nested calls. */
7141 /* Find maximum size of vector to hold converted arguments. */
7148 /* The implicit parameters to a constructor are not considered by overload
7149 resolution, and must be of the proper type. */
7151 {
7152 tree object_arg;
7154 {
7157 }
7158 else
7159 {
7162 }
7165 /* We should never try to call the abstract constructor. */
7169 {
7173 }
7174 }
7175 /* Bypass access control for 'this' parameter. */
7177 {
7180 ? first_arg
7183 tree converted_arg;
7184 tree base_binfo;
7187 {
7189 {
7194 }
7195 else
7197 }
7199 /* See if the function member or the whole class type is declared
7200 final and the call can be devirtualized. */
7205 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7206 X is called for an object that is not of type X, or of a type
7207 derived from X, the behavior is undefined.
7209 So we can assume that anything passed as 'this' is non-null, and
7210 optimize accordingly. */
7212 /* Convert to the base in which the function was declared. */
7215 arg,
7218 /* Check that the base class is accessible. */
7221 {
7226 else
7228 }
7229 /* If fn was found by a using declaration, the conversion path
7230 will be to the derived class, not the base declaring fn. We
7231 must convert from derived to base. */
7242 else
7246 }
7251 {
7258 /* If the argument is NULL and used to (implicitly) instantiate a
7259 template function (and bind one of the template arguments to
7260 the type of 'long int'), we don't want to warn about passing NULL
7261 to non-pointer argument.
7262 For example, if we have this template function:
7264 template<typename T> void func(T x) {}
7266 we want to warn (when -Wconversion is enabled) in this case:
7268 void foo() {
7269 func<int>(NULL);
7270 }
7272 but not in this case:
7274 void foo() {
7275 func(NULL);
7276 }
7277 */
7284 /* Warn about initializer_list deduction that isn't currently in the
7285 working draft. */
7287 && flag_deduce_init_list
7291 {
7304 {
7311 }
7312 }
7314 conversion_warning
7315 ? complain
7322 else
7324 }
7326 /* Default arguments */
7328 {
7334 complain);
7335 }
7337 /* Ellipsis */
7339 {
7342 /* Do no conversions for magic varargs. */
7347 {
7348 /* Avoid infinite recursion trying to call A(...). */
7350 /* Try to call the actual copy constructor for a good error. */
7353 }
7354 else
7357 }
7364 /* Avoid actually calling copy constructors and copy assignment operators,
7365 if possible. */
7372 /* It's unsafe to elide the constructor when handling
7373 a noexcept-expression, it may evaluate to the wrong
7374 value (c++/53025). */
7376 {
7377 tree targ;
7379 tree fa;
7382 /* Pull out the real argument, disregarding const-correctness. */
7388 {
7393 }
7394 else
7399 else
7402 /* [class.copy]: the copy constructor is implicitly defined even if
7403 the implementation elided its use. */
7405 {
7409 }
7411 /* If we're creating a temp and we already have one, don't create a
7412 new one. If we're not creating a temp but we get one, use
7413 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7414 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7415 temp or an INIT_EXPR otherwise. */
7418 {
7423 }
7425 {
7427 complain));
7431 }
7432 }
7436 {
7437 tree to = stabilize_reference
7444 {
7445 /* Avoid copying empty classes. */
7450 }
7452 {
7455 }
7456 else
7457 {
7458 /* We must only copy the non-tail padding parts. */
7466 build_index_type
7475 }
7478 }
7483 /* FIXME handle trivial default constructor, too. */
7485 /* For calls to a multi-versioned function, overload resolution
7486 returns the function with the highest target priority, that is,
7487 the version that will checked for dispatching first. If this
7488 version is inlinable, a direct call to this version can be made
7489 otherwise the call should go through the dispatcher. */
7494 {
7500 }
7507 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7508 virtual functions can't be constexpr. */
7510 {
7511 tree t;
7518 complain);
7524 else
7527 }
7528 else
7529 {
7533 }
7540 }
7542 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7543 This function performs no overload resolution, conversion, or other
7544 high-level operations. */
7546 tree
7548 tsubst_flags_t complain)
7549 {
7550 tree fndecl;
7553 /* Remember roughly where this call is. */
7560 /* Check that arguments to builtin functions match the expectations. */
7567 /* If it is a built-in array notation function, then the return type of
7568 the function is the element type of the array passed in as array
7569 notation (i.e. the first parameter of the function). */
7571 {
7580 {
7582 {
7585 }
7586 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7587 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7588 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7589 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7590 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7591 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7592 The pre-defined return-type is the correct one. */
7596 }
7597 }
7599 /* Some built-in function calls will be evaluated at compile-time in
7600 fold (). Set optimize to 1 when folding __builtin_constant_p inside
7601 a constexpr function so that fold_builtin_1 doesn't fold it to 0. */
7604 && current_function_decl
7613 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7614 function call is either the operand of a decltype-specifier or the
7615 right operand of a comma operator that is the operand of a
7616 decltype-specifier, a temporary object is not introduced for the
7617 prvalue. The type of the prvalue may be incomplete. */
7619 {
7626 }
7628 }
7632 /* Make an expression which yields the address of the Java interface
7633 method FN. This is achieved by generating a call to libjava's
7634 _Jv_LookupInterfaceMethodIdx(). */
7636 static tree
7638 {
7644 {
7648 java_iface_lookup_fn
7651 }
7653 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7654 This is the first entry in the vtable. */
7656 tf_warning_or_error),
7657 integer_zero_node);
7659 /* Get the java.lang.Class pointer for the interface being called. */
7664 {
7666 iface);
7668 }
7672 /* Determine the itable index of FN. */
7675 {
7680 i++;
7681 }
7686 java_iface_lookup_fn);
7689 }
7691 /* Returns the value to use for the in-charge parameter when making a
7692 call to a function with the indicated NAME.
7694 FIXME:Can't we find a neater way to do this mapping? */
7696 tree
7698 {
7709 /* This function should only be called with one of the names listed
7710 above. */
7713 }
7715 /* Build a call to a constructor, destructor, or an assignment
7716 operator for INSTANCE, an expression with class type. NAME
7717 indicates the special member function to call; *ARGS are the
7718 arguments. ARGS may be NULL. This may change ARGS. BINFO
7719 indicates the base of INSTANCE that is to be passed as the `this'
7720 parameter to the member function called.
7722 FLAGS are the LOOKUP_* flags to use when processing the call.
7724 If NAME indicates a complete object constructor, INSTANCE may be
7725 NULL_TREE. In this case, the caller will call build_cplus_new to
7726 store the newly constructed object into a VAR_DECL. */
7728 tree
7731 {
7732 tree fns;
7733 /* The type of the subobject to be constructed or destroyed. */
7734 tree class_type;
7736 tree ret;
7745 {
7746 /* Resolve the name. */
7751 }
7757 /* Handle the special case where INSTANCE is NULL_TREE. */
7760 else
7761 {
7767 /* Convert to the base class, if necessary. */
7770 {
7772 /* For constructors and destructors, either the base is
7773 non-virtual, or it is virtual but we are doing the
7774 conversion from a constructor or destructor for the
7775 complete object. In either case, we can convert
7776 statically. */
7778 else
7779 /* However, for assignment operators, we must convert
7780 dynamically if the base is virtual. */
7783 }
7784 }
7790 /* When making a call to a constructor or destructor for a subobject
7791 that uses virtual base classes, pass down a pointer to a VTT for
7792 the subobject. */
7796 {
7797 tree vtt;
7798 tree sub_vtt;
7800 /* If the current function is a complete object constructor
7801 or destructor, then we fetch the VTT directly.
7802 Otherwise, we look it up using the VTT we were given. */
7810 current_vtt_parm,
7811 vtt);
7814 else
7818 {
7821 }
7824 }
7829 complain);
7843 }
7845 /* Return the NAME, as a C string. The NAME indicates a function that
7846 is a member of TYPE. *FREE_P is set to true if the caller must
7847 free the memory returned.
7849 Rather than go through all of this, we should simply set the names
7850 of constructors and destructors appropriately, and dispense with
7851 ctor_identifier, dtor_identifier, etc. */
7855 {
7858 /* Assume that we will not allocate memory. */
7860 /* Constructors and destructors are special. */
7862 {
7863 pretty_name
7865 /* For a destructor, add the '~'. */
7869 {
7871 /* Remember that we need to free the memory allocated. */
7873 }
7874 }
7876 {
7879 TFF_PLAIN_IDENTIFIER),
7880 NULL);
7881 /* Remember that we need to free the memory allocated. */
7883 }
7884 else
7888 }
7890 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
7891 be set, upon return, to the function called. ARGS may be NULL.
7892 This may change ARGS. */
7894 static tree
7898 {
7903 tree optype;
7905 tree name;
7908 tree call;
7909 tree fn;
7912 tree orig_instance;
7913 tree orig_fns;
7919 /* We don't know what function we're going to call, yet. */
7928 {
7932 }
7937 /* Dismantle the baselink to collect all the information we need. */
7945 {
7949 }
7960 {
7965 }
7968 /* Under DR 147 A::A() is an invalid constructor call,
7969 not a functional cast. */
7971 {
7981 complain);
7983 }
7985 /* Figure out whether to skip the first argument for the error
7986 message we will display to users if an error occurs. We don't
7987 want to display any compiler-generated arguments. The "this"
7988 pointer hasn't been added yet. However, we must remove the VTT
7989 pointer if this is a call to a base-class constructor or
7990 destructor. */
7993 {
7994 /* Callers should explicitly indicate whether they want to construct
7995 the complete object or just the part without virtual bases. */
7997 /* Similarly for destructors. */
7999 /* Remove the VTT pointer, if present. */
8003 }
8005 /* Process the argument list. */
8007 {
8011 }
8013 /* Consider the object argument to be used even if we end up selecting a
8014 static member function. */
8017 /* It's OK to call destructors and constructors on cv-qualified objects.
8018 Therefore, convert the INSTANCE to the unqualified type, if
8019 necessary. */
8022 {
8024 {
8028 }
8029 }
8033 /* For the overload resolution we need to find the actual `this`
8034 that would be captured if the call turns out to be to a
8035 non-static member function. Do not actually capture it at this
8036 point. */
8038 /* Constructors don't use the enclosing 'this'. */
8040 else
8043 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8046 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8047 initializer, not T({ }). */
8050 {
8057 /* If the initializer list has no elements and T is a class type with
8058 a default constructor, the object is value-initialized. Handle
8059 this here so we don't need to handle it wherever we use
8060 build_special_member_call. */
8063 /* For a user-provided default constructor, use the normal
8064 mechanisms so that protected access works. */
8069 /* If BASETYPE is an aggregate, we need to do aggregate
8070 initialization. */
8075 {
8081 }
8083 /* Otherwise go ahead with overload resolution. */
8088 }
8089 else
8090 {
8094 }
8099 {
8101 {
8108 else
8109 {
8112 tree arglist;
8123 }
8125 }
8127 }
8128 else
8129 {
8132 {
8135 tree arglist;
8138 {
8146 else
8152 }
8154 }
8155 else
8156 {
8164 {
8165 /* This is not an error, it is runtime undefined
8166 behavior. */
8175 fn);
8176 }
8181 {
8186 {
8187 /* We captured 'this' in the current lambda now that
8188 we know we really need it. */
8190 }
8191 else
8192 {
8195 fn);
8197 }
8198 }
8201 {
8202 /* Optimize away vtable lookup if we know that this
8203 function can't be overridden. We need to check if
8204 the context and the type where we found fn are the same,
8205 actually FN might be defined in a different class
8206 type because of a using-declaration. In this case, we
8207 do not want to perform a non-virtual call. */
8209 && same_type_ignoring_top_level_qualifiers_p
8215 /* Now we know what function is being called. */
8218 /* Build the actual CALL_EXPR. */
8220 /* In an expression of the form `a->f()' where `f' turns
8221 out to be a static member function, `a' is
8222 none-the-less evaluated. */
8231 /* An explicit call of the form "x->~X()" has type
8232 "void". However, on platforms where destructors
8233 return "this" (i.e., those where
8234 targetm.cxx.cdtor_returns_this is true), such calls
8235 will appear to have a return value of pointer type
8236 to the low-level call machinery. We do not want to
8237 change the low-level machinery, since we want to be
8238 able to optimize "delete f()" on such platforms as
8239 "operator delete(~X(f()))" (rather than generating
8240 "t = f(), ~X(t), operator delete (t)"). */
8242 }
8243 }
8244 }
8247 {
8253 {
8256 }
8259 call = (build_min_non_dep_call_vec
8263 orig_args));
8268 }
8270 /* Free all the conversions we allocated. */
8277 }
8279 /* Wrapper for above. */
8281 tree
8285 {
8286 tree ret;
8292 }
8294 /* Returns true iff standard conversion sequence ICS1 is a proper
8295 subsequence of ICS2. */
8297 static bool
8299 {
8300 /* We can assume that a conversion of the same code
8301 between the same types indicates a subsequence since we only get
8302 here if the types we are converting from are the same. */
8309 {
8319 /* At this point, ICS1 cannot be a proper subsequence of
8320 ICS2. We can get a USER_CONV when we are comparing the
8321 second standard conversion sequence of two user conversion
8322 sequences. */
8332 }
8333 }
8335 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8336 be any _TYPE nodes. */
8338 bool
8340 {
8344 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8345 considers every class derived from itself. */
8348 }
8350 /* We build the ICS for an implicit object parameter as a pointer
8351 conversion sequence. However, such a sequence should be compared
8352 as if it were a reference conversion sequence. If ICS is the
8353 implicit conversion sequence for an implicit object parameter,
8354 modify it accordingly. */
8356 static void
8358 {
8360 {
8361 /* [over.match.funcs]
8363 For non-static member functions, the type of the
8364 implicit object parameter is "reference to cv X"
8365 where X is the class of which the function is a
8366 member and cv is the cv-qualification on the member
8367 function declaration. */
8369 tree reference_type;
8371 /* The `this' parameter is a pointer to a class type. Make the
8372 implicit conversion talk about a reference to that same class
8373 type. */
8386 }
8387 }
8389 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8390 and return the initial reference binding conversion. Otherwise,
8391 leave *ICS unchanged and return NULL. */
8395 {
8397 {
8402 }
8405 }
8407 /* Compare two implicit conversion sequences according to the rules set out in
8408 [over.ics.rank]. Return values:
8410 1: ics1 is better than ics2
8411 -1: ics2 is better than ics1
8412 0: ics1 and ics2 are indistinguishable */
8414 static int
8416 {
8417 tree from_type1;
8418 tree from_type2;
8419 tree to_type1;
8420 tree to_type2;
8427 /* REF_BINDING is nonzero if the result of the conversion sequence
8428 is a reference type. In that case REF_CONV is the reference
8429 binding conversion. */
8433 /* Compare badness before stripping the reference conversion. */
8439 /* Handle implicit object parameters. */
8443 /* Handle reference parameters. */
8447 /* List-initialization sequence L1 is a better conversion sequence than
8448 list-initialization sequence L2 if L1 converts to
8449 std::initializer_list<X> for some X and L2 does not. */
8455 /* [over.ics.rank]
8457 When comparing the basic forms of implicit conversion sequences (as
8458 defined in _over.best.ics_)
8460 --a standard conversion sequence (_over.ics.scs_) is a better
8461 conversion sequence than a user-defined conversion sequence
8462 or an ellipsis conversion sequence, and
8464 --a user-defined conversion sequence (_over.ics.user_) is a
8465 better conversion sequence than an ellipsis conversion sequence
8466 (_over.ics.ellipsis_). */
8467 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8468 mismatch. If both ICS are bad, we try to make a decision based on
8469 what would have happened if they'd been good. This is not an
8470 extension, we'll still give an error when we build up the call; this
8471 just helps us give a more helpful error message. */
8481 /* Both conversions are ellipsis conversions. */
8484 /* User-defined conversion sequence U1 is a better conversion sequence
8485 than another user-defined conversion sequence U2 if they contain the
8486 same user-defined conversion operator or constructor and if the sec-
8487 ond standard conversion sequence of U1 is better than the second
8488 standard conversion sequence of U2. */
8490 /* Handle list-conversion with the same code even though it isn't always
8491 ranked as a user-defined conversion and it doesn't have a second
8492 standard conversion sequence; it will still have the desired effect.
8493 Specifically, we need to do the reference binding comparison at the
8494 end of this function. */
8497 {
8513 {
8516 }
8517 else
8518 {
8519 /* For ambiguous or aggregate conversions, use the target type as
8520 a proxy for the conversion function. */
8523 }
8525 /* We can just fall through here, after setting up
8526 FROM_TYPE1 and FROM_TYPE2. */
8529 }
8530 else
8531 {
8535 /* We're dealing with two standard conversion sequences.
8537 [over.ics.rank]
8539 Standard conversion sequence S1 is a better conversion
8540 sequence than standard conversion sequence S2 if
8542 --S1 is a proper subsequence of S2 (comparing the conversion
8543 sequences in the canonical form defined by _over.ics.scs_,
8544 excluding any Lvalue Transformation; the identity
8545 conversion sequence is considered to be a subsequence of
8546 any non-identity conversion sequence */
8557 }
8559 /* One sequence can only be a subsequence of the other if they start with
8560 the same type. They can start with different types when comparing the
8561 second standard conversion sequence in two user-defined conversion
8562 sequences. */
8564 {
8569 }
8571 /* [over.ics.rank]
8573 Or, if not that,
8575 --the rank of S1 is better than the rank of S2 (by the rules
8576 defined below):
8578 Standard conversion sequences are ordered by their ranks: an Exact
8579 Match is a better conversion than a Promotion, which is a better
8580 conversion than a Conversion.
8582 Two conversion sequences with the same rank are indistinguishable
8583 unless one of the following rules applies:
8585 --A conversion that does not a convert a pointer, pointer to member,
8586 or std::nullptr_t to bool is better than one that does.
8588 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8589 so that we do not have to check it explicitly. */
8598 /* A conversion from scalar arithmetic type to complex is worse than a
8599 conversion between scalar arithmetic types. */
8606 {
8609 else
8611 }
8617 {
8622 }
8623 /* The rules for pointers to members A::* are just like the rules
8624 for pointers A*, except opposite: if B is derived from A then
8625 A::* converts to B::*, not vice versa. For that reason, we
8626 switch the from_ and to_ variables here. */
8633 {
8638 }
8643 {
8644 /* This was one of the pointer or pointer-like conversions.
8646 [over.ics.rank]
8648 --If class B is derived directly or indirectly from class A,
8649 conversion of B* to A* is better than conversion of B* to
8650 void*, and conversion of A* to void* is better than
8651 conversion of B* to void*. */
8654 {
8656 deref_from_type2))
8659 deref_from_type1))
8661 }
8664 {
8666 {
8668 {
8670 deref_to_type1))
8672 }
8673 /* We know that DEREF_TO_TYPE1 is `void' here. */
8675 deref_to_type2))
8677 }
8678 }
8681 {
8682 /* [over.ics.rank]
8684 --If class B is derived directly or indirectly from class A
8685 and class C is derived directly or indirectly from B,
8687 --conversion of C* to B* is better than conversion of C* to
8688 A*,
8690 --conversion of B* to A* is better than conversion of C* to
8691 A* */
8693 {
8695 deref_to_type2))
8698 deref_to_type1))
8700 }
8702 {
8704 deref_from_type1))
8707 deref_from_type2))
8709 }
8710 }
8711 }
8714 {
8717 /* [over.ics.rank]
8719 --binding of an expression of type C to a reference of type
8720 B& is better than binding an expression of type C to a
8721 reference of type A&
8723 --conversion of C to B is better than conversion of C to A, */
8726 {
8731 }
8732 }
8735 {
8738 /* [over.ics.rank]
8740 --binding of an expression of type B to a reference of type
8741 A& is better than binding an expression of type C to a
8742 reference of type A&,
8744 --conversion of B to A is better than conversion of C to A */
8747 {
8752 }
8753 }
8755 /* [over.ics.rank]
8757 --S1 and S2 differ only in their qualification conversion and yield
8758 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8759 qualification signature of type T1 is a proper subset of the cv-
8760 qualification signature of type T2 */
8764 {
8768 }
8770 /* [over.ics.rank]
8772 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8773 to an implicit object parameter of a non-static member function
8774 declared without a ref-qualifier, and either S1 binds an lvalue
8775 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8776 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8777 draft standard, 13.3.3.2)
8779 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8780 types to which the references refer are the same type except for
8781 top-level cv-qualifiers, and the type to which the reference
8782 initialized by S2 refers is more cv-qualified than the type to
8783 which the reference initialized by S1 refers.
8785 DR 1328 [over.match.best]: the context is an initialization by
8786 conversion function for direct reference binding (13.3.1.6) of a
8787 reference to function type, the return type of F1 is the same kind of
8788 reference (i.e. lvalue or rvalue) as the reference being initialized,
8789 and the return type of F2 is not. */
8792 {
8799 {
8803 /* Don't prefer a bad conversion that drops cv-quals to a bad
8804 conversion with the wrong rvalueness. */
8808 }
8811 {
8815 {
8816 /* Prefer the one that drops fewer cv-quals. */
8821 }
8823 }
8824 }
8826 /* Neither conversion sequence is better than the other. */
8828 }
8830 /* The source type for this standard conversion sequence. */
8832 static tree
8834 {
8836 {
8841 }
8843 }
8845 /* Note a warning about preferring WINNER to LOSER. We do this by storing
8846 a pointer to LOSER and re-running joust to produce the warning if WINNER
8847 is actually used. */
8849 static void
8851 {
8857 }
8859 /* Compare two candidates for overloading as described in
8860 [over.match.best]. Return values:
8862 1: cand1 is better than cand2
8863 -1: cand2 is better than cand1
8864 0: cand1 and cand2 are indistinguishable */
8866 static int
8868 tsubst_flags_t complain)
8869 {
8875 /* Candidates that involve bad conversions are always worse than those
8876 that don't. */
8882 /* If we have two pseudo-candidates for conversions to the same type,
8883 or two candidates for the same function, arbitrarily pick one. */
8888 /* Prefer a non-deleted function over an implicitly deleted move
8889 constructor or assignment operator. This differs slightly from the
8890 wording for issue 1402 (which says the move op is ignored by overload
8891 resolution), but this way produces better error messages. */
8895 {
8902 }
8904 /* a viable function F1
8905 is defined to be a better function than another viable function F2 if
8906 for all arguments i, ICSi(F1) is not a worse conversion sequence than
8907 ICSi(F2), and then */
8909 /* for some argument j, ICSj(F1) is a better conversion sequence than
8910 ICSj(F2) */
8912 /* For comparing static and non-static member functions, we ignore
8913 the implicit object parameter of the non-static function. The
8914 standard says to pretend that the static function has an object
8915 parm, but that won't work with operator overloading. */
8918 {
8924 /* We're comparing a near-match list constructor and a near-match
8925 non-list constructor. Just treat them as unordered. */
8932 else
8933 {
8936 }
8937 }
8940 {
8946 {
8948 && warn_sign_promo
8960 {
8967 else
8972 {
8976 }
8977 else
8979 }
8982 {
8985 }
8987 }
8988 }
8990 /* warn about confusing overload resolution for user-defined conversions,
8991 either between a constructor and a conversion op, or between two
8992 conversion ops. */
8997 {
9003 else
9006 /* We don't want to complain about `X::operator T1 ()'
9007 beating `X::operator T2 () const', when T2 is a no less
9008 cv-qualified version of T1. */
9011 {
9016 {
9019 }
9022 }
9023 else
9029 {
9036 {
9038 }
9039 }
9040 else
9042 }
9047 /* DR 495 moved this tiebreaker above the template ones. */
9048 /* or, if not that,
9049 the context is an initialization by user-defined conversion (see
9050 _dcl.init_ and _over.match.user_) and the standard conversion
9051 sequence from the return type of F1 to the destination type (i.e.,
9052 the type of the entity being initialized) is a better conversion
9053 sequence than the standard conversion sequence from the return type
9054 of F2 to the destination type. */
9057 {
9061 }
9063 /* or, if not that,
9064 F1 is a non-template function and F2 is a template function
9065 specialization. */
9072 /* or, if not that,
9073 F1 and F2 are template functions and the function template for F1 is
9074 more specialized than the template for F2 according to the partial
9075 ordering rules. */
9078 {
9079 winner = more_specialized_fn
9082 /* [temp.func.order]: The presence of unused ellipsis and default
9083 arguments has no effect on the partial ordering of function
9084 templates. add_function_candidate() will not have
9085 counted the "this" argument for constructors. */
9089 }
9091 /* Check whether we can discard a builtin candidate, either because we
9092 have two identical ones or matching builtin and non-builtin candidates.
9094 (Pedantically in the latter case the builtin which matched the user
9095 function should not be added to the overload set, but we spot it here.
9097 [over.match.oper]
9098 ... the builtin candidates include ...
9099 - do not have the same parameter type list as any non-template
9100 non-member candidate. */
9103 {
9109 {
9111 /* Two built-in candidates; arbitrarily pick one. */
9114 /* cand1 is built-in; prefer cand2. */
9116 else
9117 /* cand2 is built-in; prefer cand1. */
9119 }
9120 }
9122 /* For candidates of a multi-versioned function, make the version with
9123 the highest priority win. This version will be checked for dispatching
9124 first. If this version can be inlined into the caller, the front-end
9125 will simply make a direct call to this function. */
9131 {
9137 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9138 is possible that cand1->fn and cand2->fn are function versions but of
9139 different functions. Check types to see if they are versions of the same
9140 function. */
9143 {
9144 /* Always make the version with the higher priority, more
9145 specialized, win. */
9149 else
9151 }
9152 }
9154 /* If the two function declarations represent the same function (this can
9155 happen with declarations in multiple scopes and arg-dependent lookup),
9156 arbitrarily choose one. But first make sure the default args we're
9157 using match. */
9160 {
9167 {
9168 /* Don't crash if the fn is variadic. */
9173 }
9181 {
9184 {
9186 {
9188 {
9190 "default argument mismatch in "
9192 {
9197 }
9198 }
9199 else
9201 }
9202 else
9205 }
9208 }
9211 }
9213 tweak:
9215 /* Extension: If the worst conversion for one candidate is worse than the
9216 worst conversion for the other, take the first. */
9218 {
9223 {
9228 }
9234 {
9235 /* Don't choose a deleted function over ambiguity. */
9239 {
9241 "ISO C++ says that these are ambiguous, even "
9242 "though the worst conversion for the first is better than "
9246 }
9247 else
9250 }
9251 }
9255 }
9257 /* Given a list of candidates for overloading, find the best one, if any.
9258 This algorithm has a worst case of O(2n) (winner is last), and a best
9259 case of O(n/2) (totally ambiguous); much better than a sorting
9260 algorithm. */
9264 {
9269 /* Walk through the list once, comparing each current champ to the next
9270 candidate, knocking out a candidate or two with each comparison. */
9273 {
9277 else
9278 {
9280 {
9285 }
9286 else
9287 {
9290 }
9293 }
9294 }
9296 /* Make sure the champ is better than all the candidates it hasn't yet
9297 been compared to. */
9300 challenger != champ
9303 {
9307 }
9310 }
9312 /* Returns nonzero if things of type FROM can be converted to TO. */
9314 bool
9316 {
9318 /* implicit_conversion only considers user-defined conversions
9319 if it has an expression for the call argument list. */
9323 }
9325 /* Returns nonzero if things of type FROM can be converted to TO with a
9326 standard conversion. */
9328 bool
9330 {
9332 }
9334 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9336 bool
9338 tsubst_flags_t complain)
9339 {
9344 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9346 /* We want to discard any access checks done for this test,
9347 as we might not be in the appropriate access context and
9348 we'll do the check again when we actually perform the
9349 conversion. */
9356 /* Discard the access checks now. */
9358 /* Free all the conversions we allocated. */
9362 }
9364 /* Like can_convert_arg, but allows dubious conversions as well. */
9366 bool
9368 tsubst_flags_t complain)
9369 {
9373 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9375 /* Try to perform the conversion. */
9378 /* Free all the conversions we allocated. */
9382 }
9384 /* Convert EXPR to TYPE. Return the converted expression.
9386 Note that we allow bad conversions here because by the time we get to
9387 this point we are committed to doing the conversion. If we end up
9388 doing a bad conversion, convert_like will complain. */
9390 tree
9393 {
9401 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9409 {
9411 {
9412 /* If expr has unknown type, then it is an overloaded function.
9413 Call instantiate_type to get good error messages. */
9418 else
9421 }
9423 }
9425 {
9426 /* In a template, we are only concerned about determining the
9427 type of non-dependent expressions, so we do not have to
9428 perform the actual conversion. But for initializers, we
9429 need to be able to perform it at instantiation
9430 (or instantiate_non_dependent_expr) time. */
9434 }
9435 else
9438 /* Free all the conversions we allocated. */
9442 }
9444 tree
9446 {
9448 LOOKUP_IMPLICIT);
9449 }
9451 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9452 permitted. If the conversion is valid, the converted expression is
9453 returned. Otherwise, NULL_TREE is returned, except in the case
9454 that TYPE is a class type; in that case, an error is issued. If
9455 C_CAST_P is true, then this direct-initialization is taking
9456 place as part of a static_cast being attempted as part of a C-style
9457 cast. */
9459 tree
9461 tree expr,
9463 tsubst_flags_t complain)
9464 {
9470 /* [dcl.init]
9472 If the destination type is a (possibly cv-qualified) class type:
9474 -- If the initialization is direct-initialization ...,
9475 constructors are considered. ... If no constructor applies, or
9476 the overload resolution is ambiguous, the initialization is
9477 ill-formed. */
9479 {
9485 }
9487 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9491 c_cast_p,
9495 else
9498 c_cast_p,
9499 complain);
9501 /* Free all the conversions we allocated. */
9505 }
9507 /* When initializing a reference that lasts longer than a full-expression,
9508 this special rule applies:
9510 [class.temporary]
9512 The temporary to which the reference is bound or the temporary
9513 that is the complete object to which the reference is bound
9514 persists for the lifetime of the reference.
9516 The temporaries created during the evaluation of the expression
9517 initializing the reference, except the temporary to which the
9518 reference is bound, are destroyed at the end of the
9519 full-expression in which they are created.
9521 In that case, we store the converted expression into a new
9522 VAR_DECL in a new scope.
9524 However, we want to be careful not to create temporaries when
9525 they are not required. For example, given:
9527 struct B {};
9528 struct D : public B {};
9529 D f();
9530 const B& b = f();
9532 there is no need to copy the return value from "f"; we can just
9533 extend its lifetime. Similarly, given:
9535 struct S {};
9536 struct T { operator S(); };
9537 T t;
9538 const S& s = t;
9540 we can extend the lifetime of the return value of the conversion
9541 operator.
9543 The next several functions are involved in this lifetime extension. */
9545 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9546 reference is being bound to a temporary. Create and return a new
9547 VAR_DECL with the indicated TYPE; this variable will store the value to
9548 which the reference is bound. */
9550 tree
9552 {
9553 tree var;
9555 /* Create the variable. */
9558 /* Register the variable. */
9561 {
9562 /* Namespace-scope or local static; give it a mangled name. */
9563 /* FIXME share comdat with decl? */
9564 tree name;
9572 }
9573 else
9574 /* Create a new cleanup level if necessary. */
9578 }
9580 /* EXPR is the initializer for a variable DECL of reference or
9581 std::initializer_list type. Create, push and return a new VAR_DECL
9582 for the initializer so that it will live as long as DECL. Any
9583 cleanup for the new variable is returned through CLEANUP, and the
9584 code to initialize the new variable is returned through INITP. */
9586 static tree
9589 {
9590 tree init;
9591 tree type;
9592 tree var;
9594 /* Create the temporary variable. */
9598 /* If the rvalue is the result of a function call it will be
9599 a TARGET_EXPR. If it is some other construct (such as a
9600 member access expression where the underlying object is
9601 itself the result of a function call), turn it into a
9602 TARGET_EXPR here. It is important that EXPR be a
9603 TARGET_EXPR below since otherwise the INIT_EXPR will
9604 attempt to make a bitwise copy of EXPR to initialize
9605 VAR. */
9611 {
9615 }
9617 /* Recursively extend temps in this initializer. */
9621 /* Any reference temp has a non-trivial initializer. */
9624 /* If the initializer is constant, put it in DECL_INITIAL so we get
9625 static initialization and use in constant expressions. */
9628 {
9630 {
9631 /* 5.19 says that a constant expression can include an
9632 lvalue-rvalue conversion applied to "a glvalue of literal type
9633 that refers to a non-volatile temporary object initialized
9634 with a constant expression". Rather than try to communicate
9635 that this VAR_DECL is a temporary, just mark it constexpr.
9637 Currently this is only useful for initializer_list temporaries,
9638 since reference vars can't appear in constant expressions. */
9642 }
9645 }
9646 else
9647 /* Create the INIT_EXPR that will initialize the temporary
9648 variable. */
9651 {
9656 else
9657 {
9661 }
9663 /* We must be careful to destroy the temporary only
9664 after its initialization has taken place. If the
9665 initialization throws an exception, then the
9666 destructor should not be run. We cannot simply
9667 transform INIT into something like:
9669 (INIT, ({ CLEANUP_STMT; }))
9671 because emit_local_var always treats the
9672 initializer as a full-expression. Thus, the
9673 destructor would run too early; it would run at the
9674 end of initializing the reference variable, rather
9675 than at the end of the block enclosing the
9676 reference variable.
9678 The solution is to pass back a cleanup expression
9679 which the caller is responsible for attaching to
9680 the statement tree. */
9681 }
9682 else
9683 {
9686 {
9689 tls_aggregates);
9690 else
9692 static_aggregates);
9693 }
9694 else
9695 /* Check whether the dtor is callable. */
9697 }
9698 /* Avoid -Wunused-variable warning (c++/38958). */
9705 }
9707 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9708 initializing a variable of that TYPE. */
9710 tree
9713 {
9721 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9727 {
9729 {
9738 else
9742 }
9744 }
9747 /* Perform the conversion. */
9750 /* We gave an error in build_user_type_conversion_1. */
9752 else
9755 /* Free all the conversions we allocated. */
9759 }
9761 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9762 which is bound either to a reference or a std::initializer_list. */
9764 static tree
9766 {
9771 {
9775 }
9778 /* Deal with binding to a subobject. */
9782 {
9790 }
9792 }
9794 /* INIT is part of the initializer for DECL. If there are any
9795 reference or initializer lists being initialized, extend their
9796 lifetime to match that of DECL. */
9798 tree
9800 {
9807 {
9808 /* The temporary array underlying a std::initializer_list
9809 is handled like a reference temporary. */
9814 {
9818 }
9819 }
9821 {
9827 }
9830 }
9832 /* Returns true iff an initializer for TYPE could contain temporaries that
9833 need to be extended because they are bound to references or
9834 std::initializer_list. */
9836 bool
9838 {
9843 {
9850 }
9852 }
9854 /* Returns true iff TYPE is some variant of std::initializer_list. */
9856 bool
9858 {
9859 /* Look through typedefs. */
9868 }
9870 /* Returns true iff DECL is a list constructor: i.e. a constructor which
9871 will accept an argument list of a single std::initializer_list<T>. */
9873 bool
9875 {
9877 tree arg;
9889 /* There are more non-defaulted parms. */
9893 }