| blob | 3b0fd692e9fa494a60125391a90c78223f8a57fd |
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. */
49 /* The various kinds of conversion. */
52 ck_identity,
53 ck_lvalue,
54 ck_qual,
55 ck_std,
56 ck_ptr,
57 ck_pmem,
58 ck_base,
59 ck_ref_bind,
60 ck_user,
61 ck_ambig,
62 ck_list,
63 ck_aggr,
64 ck_rvalue
67 /* The rank of the conversion. Order of the enumerals matters; better
68 conversions should come earlier in the list. */
71 cr_identity,
72 cr_exact,
73 cr_promotion,
74 cr_std,
75 cr_pbool,
76 cr_user,
77 cr_ellipsis,
78 cr_bad
81 /* An implicit conversion sequence, in the sense of [over.best.ics].
82 The first conversion to be performed is at the end of the chain.
83 That conversion is always a cr_identity conversion. */
87 /* The kind of conversion represented by this step. */
88 conversion_kind kind;
89 /* The rank of this conversion. */
90 conversion_rank rank;
94 /* True if this conversion would be permitted with a bending of
95 language standards, e.g. disregarding pointer qualifiers or
96 converting integers to pointers. */
98 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
99 temporary should be created to hold the result of the
100 conversion. */
102 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
103 from a pointer-to-derived to pointer-to-base is being performed. */
105 /* If KIND is ck_ref_bind, true when either an lvalue reference is
106 being bound to an lvalue expression or an rvalue reference is
107 being bound to an rvalue expression. If KIND is ck_rvalue,
108 true when we should treat an lvalue as an rvalue (12.8p33). If
109 KIND is ck_base, always false. */
112 /* The type of the expression resulting from the conversion. */
113 tree type;
115 /* The next conversion in the chain. Since the conversions are
116 arranged from outermost to innermost, the NEXT conversion will
117 actually be performed before this conversion. This variant is
118 used only when KIND is neither ck_identity, ck_ambig nor
119 ck_list. Please use the next_conversion function instead
120 of using this field directly. */
122 /* The expression at the beginning of the conversion chain. This
123 variant is used only if KIND is ck_identity or ck_ambig. */
124 tree expr;
125 /* The array of conversions for an initializer_list, so this
126 variant is used only when KIN D is ck_list. */
129 /* The function candidate corresponding to this conversion
130 sequence. This field is only used if KIND is ck_user. */
132 };
134 #define CONVERSION_RANK(NODE) \
135 ((NODE)->bad_p ? cr_bad \
136 : (NODE)->ellipsis_p ? cr_ellipsis \
137 : (NODE)->user_conv_p ? cr_user \
138 : (NODE)->rank)
140 #define BAD_CONVERSION_RANK(NODE) \
141 ((NODE)->ellipsis_p ? cr_ellipsis \
142 : (NODE)->user_conv_p ? cr_user \
143 : (NODE)->rank)
152 tsubst_flags_t);
156 #define convert_like(CONV, EXPR, COMPLAIN) \
157 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
160 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
161 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
169 tsubst_flags_t);
184 static void add_builtin_candidates
187 static void add_builtin_candidate
191 static void build_builtin_candidate
201 tsubst_flags_t);
204 tsubst_flags_t);
224 tsubst_flags_t);
228 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
229 NAME can take many forms... */
231 bool
233 {
234 /* Just accept something we've already complained about. */
243 {
249 else
251 }
252 else
253 {
254 /* In the case of:
256 template <class T> struct S { ~S(); };
257 int i;
258 i.~S();
260 NAME will be a class template. */
263 }
268 }
270 /* We want the address of a function or method. We avoid creating a
271 pointer-to-member function. */
273 tree
275 {
278 /* We have to do these by hand to avoid real pointer to member
279 functions. */
281 {
283 {
287 complain);
288 }
290 }
291 else
295 }
297 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
298 POINTER_TYPE to those. Note, pointer to member function types
299 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
300 two variants. build_call_a is the primitive taking an array of
301 arguments, while build_call_n is a wrapper that handles varargs. */
303 tree
305 {
308 else
309 {
319 }
320 }
322 /* Update various flags in cfun and the call itself based on what is being
323 called. Split out of build_call_a so that bot_manip can use it too. */
325 void
327 {
331 /* We check both the decl and the type; a function may be known not to
332 throw without being declared throw(). */
346 }
348 tree
350 {
351 tree decl;
352 tree result_type;
353 tree fntype;
363 /* An rvalue has no cv-qualifiers. */
374 {
375 /* We invoke build_call directly for several library
376 functions. These may have been declared normally if
377 we're building libgcc, so we can't just check
378 DECL_ARTIFICIAL. */
383 }
389 /* Don't pass empty class objects by value. This is useful
390 for tags in STL, which are used to control overload resolution.
391 We don't need to handle other cases of copying empty classes. */
394 {
398 {
402 }
403 }
406 }
408 /* New overloading code. */
416 };
418 /* Information for providing diagnostics about why overloading failed. */
421 rr_none,
422 rr_arity,
423 rr_explicit_conversion,
424 rr_template_conversion,
425 rr_arg_conversion,
426 rr_bad_arg_conversion,
427 rr_template_unification,
428 rr_invalid_copy
429 };
432 /* The index of the argument, 0-based. */
434 /* The actual argument or its type. */
435 tree from;
436 /* The type of the parameter. */
437 tree to_type;
438 };
443 /* Information about an arity mismatch. */
445 /* The expected number of arguments. */
447 /* The actual number of arguments in the call. */
449 /* Whether the call was a varargs call. */
452 /* Information about an argument conversion mismatch. */
454 /* Same, but for bad argument conversions. */
456 /* Information about template unification failures. These are the
457 parameters passed to fn_type_unification. */
459 tree tmpl;
460 tree explicit_targs;
464 tree return_type;
465 unification_kind_t strict;
468 /* Information about template instantiation failures. These are the
469 parameters passed to instantiate_template. */
471 tree tmpl;
472 tree targs;
475 };
478 /* The FUNCTION_DECL that will be called if this candidate is
479 selected by overload resolution. */
480 tree fn;
481 /* If not NULL_TREE, the first argument to use when calling this
482 function. */
483 tree first_arg;
484 /* The rest of the arguments to use when calling this function. If
485 there are no further arguments this may be NULL or it may be an
486 empty vector. */
488 /* The implicit conversion sequences for each of the arguments to
489 FN. */
491 /* The number of implicit conversion sequences. */
493 /* If FN is a user-defined conversion, the standard conversion
494 sequence from the type returned by FN to the desired destination
495 type. */
498 /* If FN is a member function, the binfo indicating the path used to
499 qualify the name of FN at the call site. This path is used to
500 determine whether or not FN is accessible if it is selected by
501 overload resolution. The DECL_CONTEXT of FN will always be a
502 (possibly improper) base of this binfo. */
503 tree access_path;
504 /* If FN is a non-static member function, the binfo indicating the
505 subobject to which the `this' pointer should be converted if FN
506 is selected by overload resolution. The type pointed to by
507 the `this' pointer must correspond to the most derived class
508 indicated by the CONVERSION_PATH. */
509 tree conversion_path;
510 tree template_decl;
511 tree explicit_targs;
516 /* The flags active in add_candidate. */
518 };
520 /* Returns true iff T is a null pointer constant in the sense of
521 [conv.ptr]. */
523 bool
525 {
526 /* [conv.ptr]
528 A null pointer constant is an integral constant expression
529 (_expr.const_) rvalue of integer type that evaluates to zero or
530 an rvalue of type std::nullptr_t. */
534 {
535 /* Core issue 903 says only literal 0 is a null pointer constant. */
541 }
543 }
545 /* Returns true iff T is a null member pointer value (4.11). */
547 bool
549 {
558 else
560 }
562 /* Returns nonzero if PARMLIST consists of only default parms,
563 ellipsis, and/or undeduced parameter packs. */
565 bool
567 {
574 }
576 /* Allocate N bytes of memory from the conversion obstack. The memory
577 is zeroed before being returned. */
581 {
584 {
587 }
591 }
593 /* Allocate rejection reasons. */
597 {
602 }
606 {
612 }
616 {
623 }
627 {
634 }
638 {
644 }
648 {
654 }
661 {
668 /* Copy args to our own storage. */
676 }
680 {
682 }
686 {
689 }
691 /* Dynamically allocate a conversion. */
695 {
700 }
702 #ifdef ENABLE_CHECKING
704 /* Make sure that all memory on the conversion obstack has been
705 freed. */
707 void
709 {
713 }
717 /* Dynamically allocate an array of N conversions. */
721 {
723 }
727 {
731 /* Note that the caller is responsible for filling in t->cand for
732 user-defined conversions. */
738 {
754 }
760 }
762 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
763 specialization of std::initializer_list<T>, if such a conversion is
764 possible. */
768 {
774 tree val;
776 /* Within a list-initialization we can have more user-defined
777 conversions. */
779 /* But no narrowing conversions. */
782 /* Can't make an array of these types. */
789 {
790 conversion *sub
797 }
805 {
813 }
816 }
818 /* Return the next conversion of the conversion chain (if applicable),
819 or NULL otherwise. Please use this function instead of directly
820 accessing fields of struct conversion. */
824 {
831 }
833 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
834 is a valid aggregate initializer for array type ATYPE. */
836 static bool
838 {
842 {
848 else
850 complain);
853 }
855 }
857 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
858 aggregate class, if such a conversion is possible. */
862 {
868 /* We already called reshape_init in implicit_conversion. */
870 /* The conversions within the init-list aren't affected by the enclosing
871 context; they're always simple copy-initialization. */
875 {
877 tree val;
883 /* Value-initialization of reference is ill-formed. */
885 else
886 {
890 }
896 else
898 complain);
905 }
917 }
919 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
920 array type, if such a conversion is possible. */
924 {
929 tree val;
934 /* We might need to propagate the size from the element to the array. */
939 {
943 }
948 {
949 conversion *sub
961 }
970 }
972 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
973 complex type, if such a conversion is possible. */
977 tsubst_flags_t complain)
978 {
983 tree val;
994 {
995 conversion *sub
1007 }
1016 }
1018 /* Build a representation of the identity conversion from EXPR to
1019 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1023 {
1031 }
1033 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1034 were multiple user-defined conversions to accomplish the job.
1035 Build a conversion that indicates that ambiguity. */
1039 {
1047 }
1049 tree
1051 {
1055 }
1057 /* Returns the standard conversion path (see [conv]) from type FROM to type
1058 TO, if any. For proper handling of null pointer constants, you must
1059 also pass the expression EXPR to convert from. If C_CAST_P is true,
1060 this conversion is coming from a C-style cast. */
1065 {
1069 tree qualified_to;
1073 {
1076 }
1082 {
1084 {
1090 }
1092 {
1093 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1096 }
1097 }
1104 {
1108 }
1110 {
1112 {
1113 tree bitfield_type;
1116 {
1119 }
1120 }
1124 }
1126 /* Allow conversion between `__complex__' data types. */
1128 {
1129 /* The standard conversion sequence to convert FROM to TO is
1130 the standard conversion sequence to perform componentwise
1131 conversion. */
1136 {
1139 }
1140 else
1144 }
1147 {
1151 }
1153 /* [conv.ptr]
1154 A null pointer constant can be converted to a pointer type; ... A
1155 null pointer constant of integral type can be converted to an
1156 rvalue of type std::nullptr_t. */
1164 {
1165 /* For backwards brain damage compatibility, allow interconversion of
1166 pointers and integers with a pedwarn. */
1169 }
1171 {
1172 /* For backwards brain damage compatibility, allow interconversion of
1173 enums and integers with a pedwarn. */
1176 }
1179 {
1180 tree to_pointee;
1181 tree from_pointee;
1186 ;
1190 {
1192 /* Don't try to apply restrict to void. */
1194 from = build_pointer_type
1197 }
1199 {
1204 && (same_type_ignoring_top_level_qualifiers_p
1207 {
1211 }
1214 }
1217 /* [conv.ptr]
1219 An rvalue of type "pointer to cv D," where D is a
1220 class type, can be converted to an rvalue of type
1221 "pointer to cv B," where B is a base class (clause
1222 _class.derived_) of D. If B is an inaccessible
1223 (clause _class.access_) or ambiguous
1224 (_class.member.lookup_) base class of D, a program
1225 that necessitates this conversion is ill-formed.
1226 Therefore, we use DERIVED_FROM_P, and do not check
1227 access or uniqueness. */
1229 {
1230 from =
1236 }
1239 {
1242 }
1243 else
1244 {
1247 }
1252 /* In a C-style cast, we ignore CV-qualification because we
1253 are allowed to perform a static_cast followed by a
1254 const_cast. */
1259 /* converting from string constant to char *. */
1261 /* Allow conversions among compatible ObjC pointer types (base
1262 conversions have been already handled above). */
1267 {
1270 }
1271 else
1275 }
1277 {
1289 tbase,
1295 }
1297 {
1298 /* [conv.bool]
1300 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1301 to member type can be converted to a prvalue of type bool. ...
1302 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1303 std::nullptr_t can be converted to a prvalue of type bool; */
1309 {
1320 }
1323 }
1324 /* We don't check for ENUMERAL_TYPE here because there are no standard
1325 conversions to enum type. */
1326 /* As an extension, allow conversion to complex type. */
1328 {
1335 /* Give this a better rank if it's a promotion. */
1339 }
1345 {
1349 /* The derived-to-base conversion indicates the initialization
1350 of a parameter with base type from an object of a derived
1351 type. A temporary object is created to hold the result of
1352 the conversion unless we're binding directly to a reference. */
1354 }
1355 else
1362 }
1364 /* Returns nonzero if T1 is reference-related to T2. */
1366 bool
1368 {
1375 /* [dcl.init.ref]
1377 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1378 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1379 of T2. */
1383 }
1385 /* Returns nonzero if T1 is reference-compatible with T2. */
1387 static bool
1389 {
1390 /* [dcl.init.ref]
1392 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1393 reference-related to T2 and cv1 is the same cv-qualification as,
1394 or greater cv-qualification than, cv2. */
1397 }
1399 /* A reference of the indicated TYPE is being bound directly to the
1400 expression represented by the implicit conversion sequence CONV.
1401 Return a conversion sequence for this binding. */
1405 {
1406 tree t;
1413 /* [over.ics.rank]
1415 When a parameter of reference type binds directly
1416 (_dcl.init.ref_) to an argument expression, the implicit
1417 conversion sequence is the identity conversion, unless the
1418 argument expression has a type that is a derived class of the
1419 parameter type, in which case the implicit conversion sequence is
1420 a derived-to-base Conversion.
1422 If the parameter binds directly to the result of applying a
1423 conversion function to the argument expression, the implicit
1424 conversion sequence is a user-defined conversion sequence
1425 (_over.ics.user_), with the second standard conversion sequence
1426 either an identity conversion or, if the conversion function
1427 returns an entity of a type that is a derived class of the
1428 parameter type, a derived-to-base conversion. */
1430 {
1431 /* Represent the derived-to-base conversion. */
1433 /* We will actually be binding to the base-class subobject in
1434 the derived class, so we mark this conversion appropriately.
1435 That way, convert_like knows not to generate a temporary. */
1437 }
1439 }
1441 /* Returns the conversion path from type FROM to reference type TO for
1442 purposes of reference binding. For lvalue binding, either pass a
1443 reference type to FROM or an lvalue expression to EXPR. If the
1444 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1445 the conversion returned. If C_CAST_P is true, this
1446 conversion is coming from a C-style cast. */
1450 tsubst_flags_t complain)
1451 {
1455 tree tfrom;
1458 cp_lvalue_kind gl_kind;
1462 {
1467 }
1470 {
1472 /* DR 1288: Otherwise, if the initializer list has a single element
1473 of type E and ... [T's] referenced type is reference-related to E,
1474 the object or reference is initialized from that element... */
1476 {
1482 {
1486 }
1487 }
1488 /* Otherwise, if T is a reference type, a prvalue temporary of the
1489 type referenced by T is copy-list-initialized or
1490 direct-list-initialized, depending on the kind of initialization
1491 for the reference, and the reference is bound to that temporary. */
1494 skip:;
1495 }
1498 {
1503 else
1505 }
1507 {
1510 /* A class prvalue is not a glvalue. */
1512 }
1513 else
1521 /* Figure out whether or not the types are reference-related and
1522 reference compatible. We have to do this after stripping
1523 references from FROM. */
1525 /* If this is a C cast, first convert to an appropriately qualified
1526 type, so that we can later do a const_cast to the desired type. */
1532 /* Directly bind reference when target expression's type is compatible with
1533 the reference and expression is an lvalue. In DR391, the wording in
1534 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1535 const and rvalue references to rvalues of compatible class type.
1536 We should also do direct bindings for non-class xvalues. */
1538 && (gl_kind
1542 {
1543 /* [dcl.init.ref]
1545 If the initializer expression
1547 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1548 is reference-compatible with "cv2 T2,"
1550 the reference is bound directly to the initializer expression
1551 lvalue.
1553 [...]
1554 If the initializer expression is an rvalue, with T2 a class type,
1555 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1556 is bound to the object represented by the rvalue or to a sub-object
1557 within that object. */
1563 /* The top-level caller requested that we pretend that the lvalue
1564 be treated as an rvalue. */
1567 /* Handle rvalue reference to function properly. */
1568 conv->rvaluedness_matches_p
1570 else
1571 conv->rvaluedness_matches_p
1576 /* For the purposes of overload resolution, we ignore the fact
1577 this expression is a bitfield or packed field. (In particular,
1578 [over.ics.ref] says specifically that a function with a
1579 non-const reference parameter is viable even if the
1580 argument is a bitfield.)
1582 However, when we actually call the function we must create
1583 a temporary to which to bind the reference. If the
1584 reference is volatile, or isn't const, then we cannot make
1585 a temporary, so we just issue an error when the conversion
1586 actually occurs. */
1589 /* Don't allow binding of lvalues (other than function lvalues) to
1590 rvalue references. */
1596 /* Nor the reverse. */
1607 }
1608 /* [class.conv.fct] A conversion function is never used to convert a
1609 (possibly cv-qualified) object to the (possibly cv-qualified) same
1610 object type (or a reference to it), to a (possibly cv-qualified) base
1611 class of that type (or a reference to it).... */
1614 {
1615 /* [dcl.init.ref]
1617 If the initializer expression
1619 -- has a class type (i.e., T2 is a class type) can be
1620 implicitly converted to an lvalue of type "cv3 T3," where
1621 "cv1 T1" is reference-compatible with "cv3 T3". (this
1622 conversion is selected by enumerating the applicable
1623 conversion functions (_over.match.ref_) and choosing the
1624 best one through overload resolution. (_over.match_).
1626 the reference is bound to the lvalue result of the conversion
1627 in the second case. */
1629 complain);
1632 }
1634 /* From this point on, we conceptually need temporaries, even if we
1635 elide them. Only the cases above are "direct bindings". */
1639 /* [over.ics.rank]
1641 When a parameter of reference type is not bound directly to an
1642 argument expression, the conversion sequence is the one required
1643 to convert the argument expression to the underlying type of the
1644 reference according to _over.best.ics_. Conceptually, this
1645 conversion sequence corresponds to copy-initializing a temporary
1646 of the underlying type with the argument expression. Any
1647 difference in top-level cv-qualification is subsumed by the
1648 initialization itself and does not constitute a conversion. */
1650 /* [dcl.init.ref]
1652 Otherwise, the reference shall be an lvalue reference to a
1653 non-volatile const type, or the reference shall be an rvalue
1654 reference.
1656 We try below to treat this as a bad conversion to improve diagnostics,
1657 but if TO is an incomplete class, we need to reject this conversion
1658 now to avoid unnecessary instantiation. */
1663 /* We're generating a temporary now, but don't bind any more in the
1664 conversion (specifically, don't slice the temporary returned by a
1665 conversion operator). */
1668 /* Core issue 899: When [copy-]initializing a temporary to be bound
1669 to the first parameter of a copy constructor (12.8) called with
1670 a single argument in the context of direct-initialization,
1671 explicit conversion functions are also considered.
1673 So don't set LOOKUP_ONLYCONVERTING in that case. */
1684 {
1685 /* If initializing the temporary used a conversion function,
1686 recalculate the second conversion sequence. */
1690 {
1693 conversion *new_second
1699 }
1700 }
1703 /* This reference binding, unlike those above, requires the
1704 creation of a temporary. */
1708 /* [dcl.init.ref]
1710 Otherwise, the reference shall be an lvalue reference to a
1711 non-volatile const type, or the reference shall be an rvalue
1712 reference. */
1716 /* [dcl.init.ref]
1718 Otherwise, a temporary of type "cv1 T1" is created and
1719 initialized from the initializer expression using the rules for a
1720 non-reference copy initialization. If T1 is reference-related to
1721 T2, cv1 must be the same cv-qualification as, or greater
1722 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1727 }
1729 /* Returns the implicit conversion sequence (see [over.ics]) from type
1730 FROM to type TO. The optional expression EXPR may affect the
1731 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1732 true, this conversion is coming from a C-style cast. */
1737 {
1744 /* Other flags only apply to the primary function in overload
1745 resolution, or after we've chosen one. */
1750 /* FIXME: actually we don't want warnings either, but we can't just
1751 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1752 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1753 We really ought not to issue that warning until we've committed
1754 to that conversion. */
1757 /* Call reshape_init early to remove redundant braces. */
1762 {
1767 }
1771 else
1778 {
1782 /* As an extension, allow list-initialization of _Complex. */
1784 {
1788 }
1790 /* Allow conversion from an initializer-list with one element to a
1791 scalar type. */
1793 {
1795 tree elt;
1801 else
1807 {
1810 /* Too many levels of braces, i.e. '{{1}}'. */
1813 }
1814 }
1817 }
1823 {
1835 /* We used to try to bind a reference to a temporary here, but that
1836 is now handled after the recursive call to this function at the end
1837 of reference_binding. */
1839 }
1842 }
1844 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1845 functions. ARGS will not be changed until a single candidate is
1846 selected. */
1855 {
1873 }
1875 /* Return the number of remaining arguments in the parameter list
1876 beginning with ARG. */
1878 static int
1880 {
1885 n++;
1888 }
1890 /* Create an overload candidate for the function or method FN called
1891 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1892 FLAGS is passed on to implicit_conversion.
1894 This does not change ARGS.
1896 CTYPE, if non-NULL, is the type we want to pretend this function
1897 comes from for purposes of overload resolution. */
1904 tsubst_flags_t complain)
1905 {
1909 tree parmnode;
1915 /* At this point we should not see any functions which haven't been
1916 explicitly declared, except for friend functions which will have
1917 been found using argument dependent lookup. */
1920 /* The `this', `in_chrg' and VTT arguments to constructors are not
1921 considered in overload resolution. */
1923 {
1927 {
1930 }
1931 }
1932 else
1938 /* 13.3.2 - Viable functions [over.match.viable]
1939 First, to be a viable function, a candidate function shall have enough
1940 parameters to agree in number with the arguments in the list.
1942 We need to check this first; otherwise, checking the ICSes might cause
1943 us to produce an ill-formed template instantiation. */
1947 {
1951 }
1955 {
1959 }
1960 /* When looking for a function from a subobject from an implicit
1961 copy/move constructor/operator=, don't consider anything that takes (a
1962 reference to) an unrelated type. See c++/44909 and core 1092. */
1964 {
1970 else
1973 {
1976 ctype))
1978 }
1980 /* This only applies at the top level. */
1982 }
1987 /* Second, for F to be a viable function, there shall exist for each
1988 argument an implicit conversion sequence that converts that argument
1989 to the corresponding parameter of F. */
1994 {
1996 tree arg;
2005 else
2014 {
2020 /* The type of the implicit object parameter ('this') for
2021 overload resolution is not always the same as for the
2022 function itself; conversion functions are considered to
2023 be members of the class being converted, and functions
2024 introduced by a using-declaration are considered to be
2025 members of the class that uses them.
2027 Since build_over_call ignores the ICS for the `this'
2028 parameter, we can just change the parm type. */
2030 {
2031 parmtype = cp_build_qualified_type
2034 {
2035 /* If the function has a ref-qualifier, the implicit
2036 object parameter has reference type. */
2039 /* The special handling of 'this' conversions in compare_ics
2040 does not apply if there is a ref-qualifier. */
2042 }
2043 else
2044 {
2048 }
2049 }
2051 /* Core issue 899: When [copy-]initializing a temporary to be bound
2052 to the first parameter of a copy constructor (12.8) called with
2053 a single argument in the context of direct-initialization,
2054 explicit conversion functions are also considered.
2056 So set LOOKUP_COPY_PARM to let reference_binding know that
2057 it's being called in that context. We generalize the above
2058 to handle move constructors and template constructors as well;
2059 the standardese should soon be updated similarly. */
2063 && (same_type_ignoring_top_level_qualifiers_p
2065 {
2068 /* We allow user-defined conversions within init-lists, but
2069 don't list-initialize the copy parm, as that would mean
2070 using two levels of braces for the same type. */
2074 }
2075 else
2081 }
2082 else
2083 {
2087 }
2094 {
2098 }
2101 {
2104 }
2105 }
2107 out:
2110 }
2112 /* Create an overload candidate for the conversion function FN which will
2113 be invoked for expression OBJ, producing a pointer-to-function which
2114 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2115 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2116 passed on to implicit_conversion.
2118 Actually, we don't really care about FN; we care about the type it
2119 converts to. There may be multiple conversion functions that will
2120 convert to that type, and we rely on build_user_type_conversion_1 to
2121 choose the best one; so when we create our candidate, we record the type
2122 instead of the function. */
2128 tsubst_flags_t complain)
2129 {
2147 /* Don't bother looking up the same type twice. */
2152 {
2160 else
2165 {
2169 }
2173 {
2177 }
2178 else
2179 {
2183 }
2190 {
2193 }
2200 }
2204 {
2208 }
2212 }
2214 static void
2218 {
2232 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2233 conversion ops are allowed. We handle that here by just checking for
2234 boolean_type_node because other operators don't ask for it. COND_EXPR
2235 also does contextual conversion to bool for the first operand, but we
2236 handle that in build_conditional_expr, and type1 here is operand 2. */
2241 {
2248 {
2250 /* We need something for printing the candidate. */
2254 }
2256 {
2260 }
2262 }
2264 /* For COND_EXPR we rearranged the arguments; undo that now. */
2266 {
2271 complain);
2274 else
2275 {
2278 boolean_type_node);
2279 }
2280 }
2287 }
2289 static bool
2291 {
2293 }
2295 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2297 static bool
2299 {
2300 /* [over.built]
2302 In this section, the term promoted integral type is used to refer
2303 to those integral types which are preserved by integral promotion
2304 (including e.g. int and long but excluding e.g. char).
2305 Similarly, the term promoted arithmetic type refers to promoted
2306 integral types plus floating types. */
2310 }
2312 /* Create any builtin operator overload candidates for the operator in
2313 question given the converted operand types TYPE1 and TYPE2. The other
2314 args are passed through from add_builtin_candidates to
2315 build_builtin_candidate.
2317 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2318 If CODE is requires candidates operands of the same type of the kind
2319 of which TYPE1 and TYPE2 are, we add both candidates
2320 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2322 static void
2326 tsubst_flags_t complain)
2327 {
2329 {
2337 }
2340 {
2342 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2343 and VQ is either volatile or empty, there exist candidate operator
2344 functions of the form
2345 VQ T& operator++(VQ T&);
2346 T operator++(VQ T&, int);
2347 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2348 type other than bool, and VQ is either volatile or empty, there exist
2349 candidate operator functions of the form
2350 VQ T& operator--(VQ T&);
2351 T operator--(VQ T&, int);
2352 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2353 complete object type, and VQ is either volatile or empty, there exist
2354 candidate operator functions of the form
2355 T*VQ& operator++(T*VQ&);
2356 T*VQ& operator--(T*VQ&);
2357 T* operator++(T*VQ&, int);
2358 T* operator--(T*VQ&, int); */
2367 {
2370 }
2373 /* 7 For every cv-qualified or cv-unqualified object type T, there
2374 exist candidate operator functions of the form
2376 T& operator*(T*);
2378 8 For every function type T, there exist candidate operator functions of
2379 the form
2380 T& operator*(T*); */
2389 /* 9 For every type T, there exist candidate operator functions of the form
2390 T* operator+(T*);
2392 10For every promoted arithmetic type T, there exist candidate operator
2393 functions of the form
2394 T operator+(T);
2395 T operator-(T); */
2405 /* 11For every promoted integral type T, there exist candidate operator
2406 functions of the form
2407 T operator~(T); */
2414 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2415 is the same type as C2 or is a derived class of C2, T is a complete
2416 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2417 there exist candidate operator functions of the form
2418 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2419 where CV12 is the union of CV1 and CV2. */
2423 {
2431 }
2434 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2435 didate operator functions of the form
2436 LR operator*(L, R);
2437 LR operator/(L, R);
2438 LR operator+(L, R);
2439 LR operator-(L, R);
2440 bool 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 where LR is the result of the usual arithmetic conversions between
2447 types L and R.
2449 14For every pair of types T and I, where T is a cv-qualified or cv-
2450 unqualified complete object type and I is a promoted integral type,
2451 there exist candidate operator functions of the form
2452 T* operator+(T*, I);
2453 T& operator[](T*, I);
2454 T* operator-(T*, I);
2455 T* operator+(I, T*);
2456 T& operator[](I, T*);
2458 15For every T, where T is a pointer to complete object type, there exist
2459 candidate operator functions of the form112)
2460 ptrdiff_t operator-(T, T);
2462 16For every pointer or enumeration type T, there exist candidate operator
2463 functions of the form
2464 bool operator<(T, T);
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);
2471 17For every pointer to member type T, there exist candidate operator
2472 functions of the form
2473 bool operator==(T, T);
2474 bool operator!=(T, T); */
2481 {
2484 }
2497 {
2500 }
2502 {
2505 }
2506 /* Fall through. */
2522 {
2525 }
2528 {
2531 }
2539 {
2542 }
2544 {
2547 }
2550 /* 18For every pair of promoted integral types L and R, there exist candi-
2551 date operator functions of the form
2552 LR operator%(L, R);
2553 LR operator&(L, R);
2554 LR operator^(L, R);
2555 LR operator|(L, R);
2556 L operator<<(L, R);
2557 L operator>>(L, R);
2558 where LR is the result of the usual arithmetic conversions between
2559 types L and R. */
2567 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2571 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2572 type, VQ is either volatile or empty, and R is a promoted arithmetic
2573 type, there exist candidate operator functions of the form
2574 VQ L& operator=(VQ L&, R);
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);
2580 20For every pair T, VQ), where T is any type and VQ is either volatile
2581 or empty, there exist candidate operator functions of the form
2582 T*VQ& operator=(T*VQ&, T*);
2584 21For every pair T, VQ), where T is a pointer to member type and VQ is
2585 either volatile or empty, there exist candidate operator functions of
2586 the form
2587 VQ T& operator=(VQ T&, T);
2589 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2590 unqualified complete object type, VQ is either volatile or empty, and
2591 I is a promoted integral type, there exist candidate operator func-
2592 tions of the form
2593 T*VQ& operator+=(T*VQ&, I);
2594 T*VQ& operator-=(T*VQ&, I);
2596 23For every triple L, VQ, R), where L is an integral or enumeration
2597 type, VQ is either volatile or empty, and R is a promoted integral
2598 type, there exist candidate operator functions of the form
2600 VQ L& operator%=(VQ L&, R);
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); */
2609 {
2613 {
2616 }
2629 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2642 {
2645 }
2650 }
2655 /* [over.built]
2657 For every pair of promoted arithmetic types L and R, there
2658 exist candidate operator functions of the form
2660 LR operator?(bool, L, R);
2662 where LR is the result of the usual arithmetic conversions
2663 between types L and R.
2665 For every type T, where T is a pointer or pointer-to-member
2666 type, there exist candidate operator functions of the form T
2667 operator?(bool, T, T); */
2671 /* That's OK. */
2674 /* Otherwise, the types should be pointers. */
2678 /* We don't check that the two types are the same; the logic
2679 below will actually create two candidates; one in which both
2680 parameter types are TYPE1, and one in which both parameter
2681 types are TYPE2. */
2692 }
2694 /* Make sure we don't create builtin candidates with dependent types. */
2698 {
2699 /* Try to recover if one of the types is non-dependent. But if
2700 there's only one type, there's nothing we can do. */
2703 /* And we lose if both are dependent. */
2706 /* Or if they have different forms. */
2714 }
2716 /* If we're dealing with two pointer types or two enumeral types,
2717 we need candidates for both of them. */
2726 {
2728 {
2730 error_mark_node,
2731 error_mark_node,
2732 CPO_CONVERSION,
2733 tf_none);
2735 {
2736 build_builtin_candidate
2740 }
2741 }
2743 build_builtin_candidate
2745 build_builtin_candidate
2748 }
2750 build_builtin_candidate
2752 }
2754 tree
2756 {
2762 }
2764 /* There are three conditions of builtin candidates:
2766 1) bool-taking candidates. These are the same regardless of the input.
2767 2) pointer-pair taking candidates. These are generated for each type
2768 one of the input types converts to.
2769 3) arithmetic candidates. According to the standard, we should generate
2770 all of these, but I'm trying not to...
2772 Here we generate a superset of the possible candidates for this particular
2773 case. That is a subset of the full set the standard defines, plus some
2774 other cases which the standard disallows. add_builtin_candidate will
2775 filter out the invalid set. */
2777 static void
2781 {
2785 /* TYPES[i] is the set of possible builtin-operator parameter types
2786 we will consider for the Ith argument. */
2791 {
2794 else
2796 }
2799 {
2800 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2801 and VQ is either volatile or empty, there exist candidate operator
2802 functions of the form
2803 VQ T& operator++(VQ T&); */
2813 /* 24There also exist candidate operator functions of the form
2814 bool operator!(bool);
2815 bool operator&&(bool, bool);
2816 bool operator||(bool, bool); */
2819 build_builtin_candidate
2826 build_builtin_candidate
2844 /* Fall through. */
2848 }
2854 {
2856 ;
2858 {
2859 tree convs;
2867 {
2872 }
2878 {
2891 {
2897 }
2901 }
2902 }
2903 else
2904 {
2909 {
2915 }
2917 }
2918 }
2920 /* Run through the possible parameter types of both arguments,
2921 creating candidates with those parameter types. */
2923 {
2925 tree u;
2929 add_builtin_candidate
2932 else
2933 add_builtin_candidate
2936 }
2940 }
2943 /* If TMPL can be successfully instantiated as indicated by
2944 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2946 TMPL is the template. EXPLICIT_TARGS are any explicit template
2947 arguments. ARGLIST is the arguments provided at the call-site.
2948 This does not change ARGLIST. The RETURN_TYPE is the desired type
2949 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2950 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2951 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2959 tsubst_flags_t complain)
2960 {
2970 tree arg;
2972 tree fn;
2976 /* We don't do deduction on the in-charge parameter, the VTT
2977 parameter or 'this'. */
2979 {
2982 else
2984 }
2989 {
2992 else
2994 }
3004 {
3007 }
3011 {
3014 }
3019 args_without_in_chrg,
3020 nargs_without_in_chrg,
3025 {
3026 /* Don't repeat unification later if it already resulted in errors. */
3030 nargs_without_in_chrg,
3032 else
3035 }
3037 /* In [class.copy]:
3039 A member function template is never instantiated to perform the
3040 copy of a class object to an object of its class type.
3042 It's a little unclear what this means; the standard explicitly
3043 does allow a template to be used to copy a class. For example,
3044 in:
3046 struct A {
3047 A(A&);
3048 template <class T> A(const T&);
3049 };
3050 const A f ();
3051 void g () { A a (f ()); }
3053 the member template will be used to make the copy. The section
3054 quoted above appears in the paragraph that forbids constructors
3055 whose only parameter is (a possibly cv-qualified variant of) the
3056 class type, and a logical interpretation is that the intent was
3057 to forbid the instantiation of member templates which would then
3058 have that form. */
3060 {
3063 ctype))
3064 {
3067 }
3068 }
3071 /* Aha, this is a conversion function. */
3074 else
3079 /* This situation can occur if a member template of a template
3080 class is specialized. Then, instantiate_template might return
3081 an instantiation of the specialization, in which case the
3082 DECL_TI_TEMPLATE field will point at the original
3083 specialization. For example:
3085 template <class T> struct S { template <class U> void f(U);
3086 template <> void f(int) {}; };
3087 S<double> sd;
3088 sd.f(3);
3090 Here, TMPL will be template <class U> S<double>::f(U).
3091 And, instantiate template will give us the specialization
3092 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3093 for this will point at template <class T> template <> S<T>::f(int),
3094 so that we can find the definition. For the purposes of
3095 overload resolution, however, we want the original TMPL. */
3097 else
3102 fail:
3105 }
3114 {
3115 return
3120 }
3129 {
3130 return
3134 complain);
3135 }
3137 /* The CANDS are the set of candidates that were considered for
3138 overload resolution. Return the set of viable candidates, or CANDS
3139 if none are viable. If any of the candidates were viable, set
3140 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3141 considered viable only if it is strictly viable. */
3147 {
3153 /* Be strict inside templates, since build_over_call won't actually
3154 do the conversions to get pedwarns. */
3164 {
3168 {
3169 /* Be strict in the presence of a viable candidate. Also if
3170 there are template candidates, so that we get deduction errors
3171 for them instead of silently preferring a bad conversion. */
3174 {
3175 /* Put any spliced near matches back onto the main list so
3176 that we see them if there is no strict match. */
3182 }
3183 }
3186 {
3194 }
3195 else
3197 }
3200 }
3202 static bool
3204 {
3209 }
3211 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3212 words, it is about to become the "this" pointer for a member
3213 function call. Take the address of the object. */
3215 static tree
3217 {
3218 /* In a template, we are only concerned about the type of the
3219 expression, so we can take a shortcut. */
3224 }
3226 /* Returns true iff functions are equivalent. Equivalent functions are
3227 not '==' only if one is a function-local extern function or if
3228 both are extern "C". */
3232 {
3241 }
3243 /* Print information about a candidate being rejected due to INFO. */
3245 static void
3247 {
3252 {
3253 /* Conversion of implicit `this' argument failed. */
3255 /* A bad conversion for 'this' must be discarding cv-quals. */
3258 from);
3259 else
3263 }
3265 {
3270 tf_warning_or_error);
3271 }
3273 /* Conversion of conversion function return value failed. */
3276 else
3279 }
3281 /* Print information about a candidate with WANT parameters and we found
3282 HAVE. */
3284 static void
3286 {
3291 }
3293 /* Print information about one overload candidate CANDIDATE. MSGSTR
3294 is the text to print before the candidate itself.
3296 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3297 to have been run through gettext by the caller. This wart makes
3298 life simpler in print_z_candidates and for the translators. */
3300 static void
3303 {
3310 {
3321 else
3324 }
3331 else
3333 /* Give the user some information about why this candidate failed. */
3335 {
3339 {
3352 "cannot be converted to %qT with a qualification "
3358 "conversion function specialization to %qT is not an "
3363 /* We use template_unification_error_rejection if unification caused
3364 actual non-SFINAE errors, in which case we don't need to repeat
3365 them here. */
3367 {
3371 }
3372 /* Re-run template unification with diagnostics. */
3376 (make_tree_vec
3387 " a constructor taking a single argument of its own "
3392 /* This candidate didn't have any issues or we failed to
3393 handle a particular code. Either way... */
3395 }
3396 }
3397 }
3399 static void
3401 {
3408 /* Remove non-viable deleted candidates. */
3411 {
3416 else
3418 }
3419 /* ...if there are any non-deleted ones. */
3423 /* There may be duplicates in the set of candidates. We put off
3424 checking this condition as long as possible, since we have no way
3425 to eliminate duplicates from a set of functions in less than n^2
3426 time. Now we are about to emit an error message, so it is more
3427 permissible to go slowly. */
3429 {
3431 /* Skip builtin candidates and conversion functions. */
3436 {
3440 else
3442 }
3443 }
3447 }
3449 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3450 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3451 the result of the conversion function to convert it to the final
3452 desired type. Merge the two sequences into a single sequence,
3453 and return the merged sequence. */
3457 {
3463 /* Find the end of the second conversion sequence. */
3465 {
3466 /* The entire sequence is a user-conversion sequence. */
3470 }
3472 /* Replace the identity conversion with the user conversion
3473 sequence. */
3477 }
3479 /* Handle overload resolution for initializing an object of class type from
3480 an initializer list. First we look for a suitable constructor that
3481 takes a std::initializer_list; if we don't find one, we then look for a
3482 non-list constructor.
3484 Parameters are as for add_candidates, except that the arguments are in
3485 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3486 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3488 static void
3495 tsubst_flags_t complain)
3496 {
3501 /* We're looking for a ctor for list-initialization. */
3503 /* And we don't allow narrowing conversions. We also use this flag to
3504 avoid the copy constructor call for copy-list-initialization. */
3507 /* Always use the default constructor if the list is empty (DR 990). */
3510 ;
3511 /* If the class has a list ctor, try passing the list as a single
3512 argument first, but only consider list ctors. */
3514 {
3522 }
3526 /* We aren't looking for list-ctors anymore. */
3528 /* We allow more user-defined conversions within an init-list. */
3534 }
3536 /* Returns the best overload candidate to perform the requested
3537 conversion. This function is used for three the overloading situations
3538 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3539 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3540 per [dcl.init.ref], so we ignore temporary bindings. */
3544 tsubst_flags_t complain)
3545 {
3547 tree fromtype;
3561 /* We represent conversion within a hierarchy using RVALUE_CONV and
3562 BASE_CONV, as specified by [over.best.ics]; these become plain
3563 constructor calls, as specified in [dcl.init]. */
3568 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3569 creating a garbage BASELINK; constructors can't be inherited. */
3573 {
3578 {
3579 /* [class.conv.fct] A conversion function is never used to
3580 convert a (possibly cv-qualified) object to the (possibly
3581 cv-qualified) same object type (or a reference to it), to a
3582 (possibly cv-qualified) base class of that type (or a
3583 reference to it)... */
3584 }
3585 else
3587 }
3594 /* It's OK to bind a temporary for converting constructor arguments, but
3595 not in converting the return value of a conversion operator. */
3601 {
3606 /* We should never try to call the abstract or base constructor
3607 from here. */
3612 {
3613 /* List-initialization. */
3617 }
3618 else
3619 {
3624 }
3627 {
3630 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3631 set, then this is copy-initialization. In that case, "The
3632 result of the call is then used to direct-initialize the
3633 object that is the destination of the copy-initialization."
3634 [dcl.init]
3636 We represent this in the conversion sequence with an
3637 rvalue conversion, which means a constructor call. */
3640 cand->second_conv
3642 }
3643 }
3649 {
3653 /* If we are called to convert to a reference type, we are trying to
3654 find a direct binding, so don't even consider temporaries. If
3655 we don't find a direct binding, the caller will try again to
3656 look for a temporary binding. */
3667 {
3669 conversion *ics
3671 rettype,
3674 complain);
3676 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3677 copy-initialization. In that case, "The result of the
3678 call is then used to direct-initialize the object that is
3679 the destination of the copy-initialization." [dcl.init]
3681 We represent this in the conversion sequence with an
3682 rvalue conversion, which means a constructor call. But
3683 don't add a second rvalue conversion if there's already
3684 one there. Which there really shouldn't be, but it's
3685 harmless since we'd add it here anyway. */
3693 {
3697 }
3700 {
3701 /* 13.3.1.5: For direct-initialization, those explicit
3702 conversion functions that are not hidden within S and
3703 yield type T or a type that can be converted to type T
3704 with a qualification conversion (4.4) are also candidate
3705 functions. */
3706 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3707 I've raised this issue with the committee. --jason 9/2011 */
3710 }
3712 {
3714 cand->reason
3717 }
3720 {
3721 /* 13.3.3.1.2: If the user-defined conversion is specified by
3722 a specialization of a conversion function template, the
3723 second standard conversion sequence shall have exact match
3724 rank. */
3727 }
3728 }
3729 }
3733 {
3737 }
3741 {
3743 {
3747 }
3754 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3755 ambiguous conversion is no worse than another user-defined
3756 conversion. */
3759 }
3761 tree convtype;
3765 /* DR 5: [in the first step of copy-initialization]...if the function
3766 is a constructor, the call initializes a temporary of the
3767 cv-unqualified version of the destination type. */
3769 else
3771 /* Build the user conversion sequence. */
3772 conv = build_conv
3774 convtype,
3780 /* Remember that this was a list-initialization. */
3784 /* Combine it with the second conversion sequence. */
3789 }
3791 /* Wrapper for above. */
3793 tree
3795 tsubst_flags_t complain)
3796 {
3798 tree ret;
3804 {
3807 else
3808 {
3811 }
3812 }
3813 else
3818 }
3820 /* Subroutine of convert_nontype_argument.
3822 EXPR is an argument for a template non-type parameter of integral or
3823 enumeration type. Do any necessary conversions (that are permitted for
3824 non-type arguments) to convert it to the parameter type.
3826 If conversion is successful, returns the converted expression;
3827 otherwise, returns error_mark_node. */
3829 tree
3831 {
3834 tree t;
3842 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3849 /* for a non-type template-parameter of integral or
3850 enumeration type, integral promotions (4.5) and integral
3851 conversions (4.7) are applied. */
3852 /* It should be sufficient to check the outermost conversion step, since
3853 there are no qualification conversions to integer type. */
3856 {
3857 /* A conversion function is OK. If it isn't constexpr, we'll
3858 complain later that the argument isn't constant. */
3860 /* The lvalue-to-rvalue conversion is OK. */
3873 /* and fall through. */
3878 }
3882 else
3885 /* Free all the conversions we allocated. */
3889 }
3891 /* Do any initial processing on the arguments to a function call. */
3895 {
3897 tree arg;
3900 {
3904 {
3908 }
3911 }
3913 }
3915 /* Perform overload resolution on FN, which is called with the ARGS.
3917 Return the candidate function selected by overload resolution, or
3918 NULL if the event that overload resolution failed. In the case
3919 that overload resolution fails, *CANDIDATES will be the set of
3920 candidates considered, and ANY_VIABLE_P will be set to true or
3921 false to indicate whether or not any of the candidates were
3922 viable.
3924 The ARGS should already have gone through RESOLVE_ARGS before this
3925 function is called. */
3932 {
3934 tree explicit_targs;
3945 /* Check FN. */
3952 {
3956 }
3958 /* Add the various candidate functions. */
3963 LOOKUP_NORMAL,
3969 else
3974 }
3976 /* Print an error message about being unable to build a call to FN with
3977 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
3978 be located; CANDIDATES is a possibly empty list of such
3979 functions. */
3981 static void
3984 {
3991 else
3996 }
3998 /* Return an expression for a call to FN (a namespace-scope function,
3999 or a static member function) with the ARGS. This may change
4000 ARGS. */
4002 tree
4004 tsubst_flags_t complain)
4005 {
4009 tree result;
4012 {
4016 }
4021 /* If this function was found without using argument dependent
4022 lookup, then we want to ignore any undeclared friend
4023 functions. */
4025 {
4030 {
4034 }
4035 }
4037 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4041 complain);
4044 {
4046 {
4053 }
4055 }
4056 else
4057 {
4059 /* If fn is template_id_expr, the call has explicit template arguments
4060 (e.g. func<int>(5)), communicate this info to build_over_call
4061 through flags so that later we can use it to decide whether to warn
4062 about peculiar null pointer conversion. */
4066 }
4068 /* Free all the conversions we allocated. */
4072 }
4074 /* Build a call to a global operator new. FNNAME is the name of the
4075 operator (either "operator new" or "operator new[]") and ARGS are
4076 the arguments provided. This may change ARGS. *SIZE points to the
4077 total number of bytes required by the allocation, and is updated if
4078 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4079 be used. If this function determines that no cookie should be
4080 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4081 is not NULL_TREE, it is evaluated before calculating the final
4082 array size, and if it fails, the array size is replaced with
4083 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4084 is non-NULL, it will be set, upon return, to the allocation
4085 function called. */
4087 tree
4091 {
4093 tree fns;
4100 /* Set to (size_t)-1 if the size check fails. */
4102 {
4108 }
4114 /* Based on:
4116 [expr.new]
4118 If this lookup fails to find the name, or if the allocated type
4119 is not a class type, the allocation function's name is looked
4120 up in the global scope.
4122 we disregard block-scope declarations of "operator new". */
4125 /* Figure out what function is being called. */
4127 complain);
4129 /* If no suitable function could be found, issue an error message
4130 and give up. */
4132 {
4136 }
4138 /* If a cookie is required, add some extra space. Whether
4139 or not a cookie is required cannot be determined until
4140 after we know which function was called. */
4142 {
4144 tree arg_types;
4147 /* Skip the size_t parameter. */
4149 /* Check the remaining parameters (if any). */
4153 ptr_type_node))
4155 /* If we need a cookie, adjust the number of bytes allocated. */
4157 {
4158 /* Update the total size. */
4160 /* Set to (size_t)-1 if the size check fails. */
4164 /* Update the argument list to reflect the adjusted size. */
4166 }
4167 else
4169 }
4171 /* Tell our caller which function we decided to call. */
4175 /* Build the CALL_EXPR. */
4177 }
4179 /* Build a new call to operator(). This may change ARGS. */
4181 static tree
4183 {
4197 {
4199 /* It's no good looking for an overloaded operator() on a
4200 pointer-to-member-function. */
4201 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4203 }
4206 {
4210 }
4211 else
4215 {
4219 }
4221 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4225 {
4233 }
4238 {
4247 {
4254 add_template_conv_candidate
4258 else
4262 }
4263 }
4265 /* Be strict here because if we choose a bad conversion candidate, the
4266 errors we get won't mention the call context. */
4269 {
4271 {
4275 }
4277 }
4278 else
4279 {
4282 {
4284 {
4288 }
4290 }
4291 /* Since cand->fn will be a type, not a function, for a conversion
4292 function, we must be careful not to unconditionally look at
4293 DECL_NAME here. */
4297 else
4298 {
4300 complain);
4303 }
4304 }
4306 /* Free all the conversions we allocated. */
4310 }
4312 /* Wrapper for above. */
4314 tree
4316 {
4317 tree ret;
4322 }
4324 /* Called by op_error to prepare format strings suitable for the error
4325 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4326 and a suffix (controlled by NTYPES). */
4330 {
4340 else
4344 }
4346 static void
4349 {
4354 else
4358 {
4364 else
4376 else
4386 else
4397 else
4407 else
4412 else
4416 else
4421 }
4422 }
4424 /* Return the implicit conversion sequence that could be used to
4425 convert E1 to E2 in [expr.cond]. */
4429 {
4435 /* [expr.cond]
4437 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4438 implicitly converted (clause _conv_) to the type "lvalue reference to
4439 T2", subject to the constraint that in the conversion the
4440 reference must bind directly (_dcl.init.ref_) to an lvalue.
4442 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4443 implicitly converted to the type "rvalue reference to T2", subject to
4444 the constraint that the reference must bind directly. */
4446 {
4449 t1,
4450 e1,
4452 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4454 complain);
4457 }
4459 /* If E2 is a prvalue or if neither of the conversions above can be done
4460 and at least one of the operands has (possibly cv-qualified) class
4461 type: */
4465 /* [expr.cond]
4467 If E1 and E2 have class type, and the underlying class types are
4468 the same or one is a base class of the other: E1 can be converted
4469 to match E2 if the class of T2 is the same type as, or a base
4470 class of, the class of T1, and the cv-qualification of T2 is the
4471 same cv-qualification as, or a greater cv-qualification than, the
4472 cv-qualification of T1. If the conversion is applied, E1 is
4473 changed to an rvalue of type T2 that still refers to the original
4474 source class object (or the appropriate subobject thereof). */
4477 {
4479 {
4484 else
4487 }
4488 else
4490 }
4491 else
4492 /* [expr.cond]
4494 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4495 converted to the type that expression E2 would have if E2 were
4496 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4499 }
4501 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4502 arguments to the conditional expression. */
4504 static tree
4506 tsubst_flags_t complain)
4507 {
4508 tree arg2_type;
4509 tree arg3_type;
4518 /* As a G++ extension, the second argument to the conditional can be
4519 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4520 c'.) If the second operand is omitted, make sure it is
4521 calculated only once. */
4523 {
4528 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4531 else
4533 }
4535 /* If something has already gone wrong, just pass that fact up the
4536 tree. */
4546 {
4551 /* force_rvalue can return error_mark on valid arguments. */
4563 {
4564 /* Rely on the error messages of the scalar version. */
4573 {
4581 }
4585 /* We could pass complain & tf_warning to unsafe_conversion_p,
4586 but the warnings (like Wsign-conversion) have already been
4587 given by the scalar build_conditional_expr_1. We still check
4588 unsafe_conversion_p to forbid truncating long long -> float. */
4590 {
4595 }
4597 {
4602 }
4612 }
4615 {
4621 {
4625 {
4631 }
4633 {
4639 }
4642 }
4643 }
4649 {
4652 "incompatible vector types in conditional expression: "
4656 }
4662 }
4664 /* [expr.cond]
4666 The first expression is implicitly converted to bool (clause
4667 _conv_). */
4669 LOOKUP_NORMAL);
4673 /* [expr.cond]
4675 If either the second or the third operand has type (possibly
4676 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4677 array-to-pointer (_conv.array_), and function-to-pointer
4678 (_conv.func_) standard conversions are performed on the second
4679 and third operands. */
4683 {
4684 /* Do the conversions. We don't these for `void' type arguments
4685 since it can't have any effect and since decay_conversion
4686 does not handle that case gracefully. */
4694 /* [expr.cond]
4696 One of the following shall hold:
4698 --The second or the third operand (but not both) is a
4699 throw-expression (_except.throw_); the result is of the
4700 type of the other and is an rvalue.
4702 --Both the second and the third operands have type void; the
4703 result is of type void and is an rvalue.
4705 We must avoid calling force_rvalue for expressions of type
4706 "void" because it will complain that their value is being
4707 used. */
4710 {
4712 {
4716 }
4719 }
4722 {
4724 {
4728 }
4731 }
4734 else
4735 {
4737 {
4740 "second operand to the conditional operator "
4741 "is of type %<void%>, but the third operand is "
4743 else
4745 "third operand to the conditional operator "
4746 "is of type %<void%>, but the second operand is "
4748 }
4750 }
4754 }
4755 /* [expr.cond]
4757 Otherwise, if the second and third operand have different types,
4758 and either has (possibly cv-qualified) class type, or if both are
4759 glvalues of the same value category and the same type except for
4760 cv-qualification, an attempt is made to convert each of those operands
4761 to the type of the other. */
4765 arg3_type)
4769 {
4774 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4780 /* [expr.cond]
4782 If both can be converted, or one can be converted but the
4783 conversion is ambiguous, the program is ill-formed. If
4784 neither can be converted, the operands are left unchanged and
4785 further checking is performed as described below. If exactly
4786 one conversion is possible, that conversion is applied to the
4787 chosen operand and the converted operand is used in place of
4788 the original operand for the remainder of this section. */
4793 {
4795 {
4802 else
4804 }
4806 }
4808 {
4812 /* Even if CONV2 is a valid conversion, the result of the
4813 conversion may be invalid. For example, if ARG3 has type
4814 "volatile X", and X does not have a copy constructor
4815 accepting a "volatile X&", then even if ARG2 can be
4816 converted to X, the conversion will fail. */
4820 }
4822 {
4829 }
4831 /* Free all the conversions we allocated. */
4837 /* If, after the conversion, both operands have class type,
4838 treat the cv-qualification of both operands as if it were the
4839 union of the cv-qualification of the operands.
4841 The standard is not clear about what to do in this
4842 circumstance. For example, if the first operand has type
4843 "const X" and the second operand has a user-defined
4844 conversion to "volatile X", what is the type of the second
4845 operand after this step? Making it be "const X" (matching
4846 the first operand) seems wrong, as that discards the
4847 qualification without actually performing a copy. Leaving it
4848 as "volatile X" seems wrong as that will result in the
4849 conditional expression failing altogether, even though,
4850 according to this step, the one operand could be converted to
4851 the type of the other. */
4859 }
4861 /* [expr.cond]
4863 If the second and third operands are glvalues of the same value
4864 category and have the same type, the result is of that type and
4865 value category. */
4869 {
4874 }
4876 /* [expr.cond]
4878 Otherwise, the result is an rvalue. If the second and third
4879 operand do not have the same type, and either has (possibly
4880 cv-qualified) class type, overload resolution is used to
4881 determine the conversions (if any) to be applied to the operands
4882 (_over.match.oper_, _over.built_). */
4886 {
4891 /* Rearrange the arguments so that add_builtin_candidate only has
4892 to know about two args. In build_builtin_candidate, the
4893 arguments are unscrambled. */
4898 COND_EXPR,
4899 NOP_EXPR,
4901 args,
4904 /* [expr.cond]
4906 If the overload resolution fails, the program is
4907 ill-formed. */
4910 {
4915 }
4918 {
4920 {
4923 }
4925 }
4927 /* [expr.cond]
4929 Otherwise, the conversions thus determined are applied, and
4930 the converted operands are used in place of the original
4931 operands for the remainder of this section. */
4940 }
4942 /* [expr.cond]
4944 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4945 and function-to-pointer (_conv.func_) standard conversions are
4946 performed on the second and third operands.
4948 We need to force the lvalue-to-rvalue conversion here for class types,
4949 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4950 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4951 regions. */
4964 /* [expr.cond]
4966 After those conversions, one of the following shall hold:
4968 --The second and third operands have the same type; the result is of
4969 that type. */
4972 /* [expr.cond]
4974 --The second and third operands have arithmetic or enumeration
4975 type; the usual arithmetic conversions are performed to bring
4976 them to a common type, and the result is of that type. */
4981 {
4982 /* In this case, there is always a common type. */
4984 arg3_type);
4987 "implicit conversion from %qT to %qT to "
4989 loc);
4993 {
4997 /* Two enumerators from the same enumeration can have different
5003 }
5010 {
5014 }
5018 }
5019 /* [expr.cond]
5021 --The second and third operands have pointer type, or one has
5022 pointer type and the other is a null pointer constant; pointer
5023 conversions (_conv.ptr_) and qualification conversions
5024 (_conv.qual_) are performed to bring them to their composite
5025 pointer type (_expr.rel_). The result is of the composite
5026 pointer type.
5028 --The second and third operands have pointer to member type, or
5029 one has pointer to member type and the other is a null pointer
5030 constant; pointer to member conversions (_conv.mem_) and
5031 qualification conversions (_conv.qual_) are performed to bring
5032 them to a common type, whose cv-qualification shall match the
5033 cv-qualification of either the second or the third operand.
5034 The result is of the common type. */
5042 {
5045 complain);
5050 }
5053 {
5058 }
5063 valid_operands:
5066 /* Avoid folding within decltype (c++/42013) and noexcept. */
5069 /* We can't use result_type below, as fold might have returned a
5070 throw_expr. */
5073 {
5074 /* Expand both sides into the same slot, hopefully the target of
5075 the ?: expression. We used to check for TARGET_EXPRs here,
5076 but now we sometimes wrap them in NOP_EXPRs so the test would
5077 fail. */
5080 /* If this expression is an rvalue, but might be mistaken for an
5081 lvalue, we must add a NON_LVALUE_EXPR. */
5083 }
5084 else
5088 }
5090 /* Wrapper for above. */
5092 tree
5094 tsubst_flags_t complain)
5095 {
5096 tree ret;
5101 }
5103 /* OPERAND is an operand to an expression. Perform necessary steps
5104 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5105 returned. */
5107 static tree
5109 {
5111 {
5114 /* Make sure the template type is instantiated now. */
5116 }
5119 }
5121 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5122 OVERLOAD) to the CANDIDATES, returning an updated list of
5123 CANDIDATES. The ARGS are the arguments provided to the call;
5124 if FIRST_ARG is non-null it is the implicit object argument,
5125 otherwise the first element of ARGS is used if needed. The
5126 EXPLICIT_TARGS are explicit template arguments provided.
5127 TEMPLATE_ONLY is true if only template functions should be
5128 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5129 add_function_candidate. */
5131 static void
5133 tree return_type,
5138 tsubst_flags_t complain)
5139 {
5140 tree ctype;
5144 unification_kind_t strict;
5145 tree fn;
5150 /* Precalculate special handling of constructors and conversion ops. */
5153 {
5157 /* We're doing return_type(x). */
5159 else
5160 /* We're doing x.operator return_type(). */
5162 /* [over.match.funcs] For conversion functions, the function
5163 is considered to be a member of the class of the implicit
5164 object argument for the purpose of defining the type of
5165 the implicit object parameter. */
5167 }
5168 else
5169 {
5171 {
5173 /* For list-initialization we consider explicit constructors
5174 and complain if one is chosen. */
5175 check_converting
5178 }
5179 else
5180 {
5183 }
5186 }
5190 else
5191 /* Delay creating the implicit this parameter until it is needed. */
5195 {
5196 tree fn_first_arg;
5206 /* Figure out which set of arguments to use. */
5208 {
5209 /* If this function is a non-static member and we didn't get an
5210 implicit object argument, move it out of args. */
5212 {
5214 tree arg;
5221 }
5225 }
5226 else
5227 {
5228 /* Otherwise, just use the list of arguments provided. */
5231 }
5235 fn,
5236 ctype,
5237 explicit_targs,
5238 fn_first_arg,
5239 fn_args,
5240 return_type,
5241 access_path,
5242 conversion_path,
5243 flags,
5244 strict,
5245 complain);
5248 fn,
5249 ctype,
5250 fn_first_arg,
5251 fn_args,
5252 access_path,
5253 conversion_path,
5254 flags,
5255 complain);
5256 }
5257 }
5259 static tree
5262 {
5265 tree fnname;
5283 {
5287 }
5288 else
5295 {
5300 /* Use build_op_new_call and build_op_delete_call instead. */
5304 /* Use build_op_call instead. */
5311 /* These are saved for the sake of warn_logical_operator. */
5321 /* These are saved for the sake of maybe_warn_bool_compare. */
5326 /* =, ->, [], () must be non-static member functions. */
5337 }
5343 /* Use build_conditional_expr instead. */
5359 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5362 /* Add namespace-scope operators to the list of functions to
5363 consider. */
5375 /* Add class-member operators to the candidate set. */
5377 {
5378 tree fns;
5382 {
5385 }
5393 }
5394 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5395 only non-member functions that have type T1 or reference to
5396 cv-qualified-opt T1 for the first argument, if the first argument
5397 has an enumeration type, or T2 or reference to cv-qualified-opt
5398 T2 for the second argument, if the second argument has an
5399 enumeration type. Filter out those that don't match. */
5401 {
5405 {
5415 {
5421 && (same_type_ignoring_top_level_qualifiers_p
5426 }
5428 /* No argument has an appropriate type, so remove this
5429 candidate function from the list. */
5431 {
5434 }
5435 }
5436 }
5442 {
5445 /* For these, the built-in candidates set is empty
5446 [over.match.oper]/3. We don't want non-strict matches
5447 because exact matches are always possible with built-in
5448 operators. The built-in candidate set for COMPONENT_REF
5449 would be empty too, but since there are no such built-in
5450 operators, we accept non-strict matches for them. */
5457 }
5461 {
5463 {
5466 /* Don't try anything fancy if we're not allowed to produce
5467 errors. */
5471 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5472 distinguish between prefix and postfix ++ and
5473 operator++() was used for both, so we allow this with
5474 -fpermissive. */
5475 else
5476 {
5482 }
5489 else
5495 /* The caller will deal with these. */
5505 {
5506 /* If one of the arguments of the operator represents
5507 an invalid use of member function pointer, try to report
5508 a meaningful error ... */
5513 else
5514 {
5515 /* ... Otherwise, report the more generic
5516 "no matching operator found" error */
5519 }
5520 }
5523 }
5524 }
5525 else
5526 {
5529 {
5531 {
5534 }
5536 }
5538 {
5544 else
5546 }
5547 else
5548 {
5549 /* Give any warnings we noticed during overload resolution. */
5551 {
5555 }
5557 /* Check for comparison of different enum types. */
5559 {
5571 {
5575 }
5579 }
5581 /* We need to strip any leading REF_BIND so that bitfields
5582 don't cause errors. This should not remove any important
5583 conversions, because builtins don't apply to class
5584 objects directly. */
5591 {
5595 else
5598 /* We need to call warn_logical_operator before
5599 converting arg2 to a boolean_type, but after
5600 decaying an enumerator to its value. */
5607 }
5609 {
5614 }
5616 }
5617 }
5619 user_defined_result_ready:
5621 /* Free all the conversions we allocated. */
5627 builtin:
5629 {
5643 /* 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
5881 "%qD is a usual (non-placement) deallocation "
5883 }
5884 }
5885 else
5887 ok:;
5888 }
5889 }
5890 else
5891 /* "Any non-placement deallocation function matches a non-placement
5892 allocation function. If the lookup finds a single matching
5893 deallocation function, that function will be called; otherwise, no
5894 deallocation function will be called." */
5897 {
5900 {
5902 /* "If a class T has a member deallocation function named
5903 operator delete with exactly one parameter, then that
5904 function is a usual (non-placement) deallocation
5905 function. If class T does not declare such an operator
5906 delete but does declare a member deallocation function named
5907 operator delete with exactly two parameters, the second of
5908 which has type std::size_t (18.2), then this function is a
5909 usual deallocation function."
5911 So in a class (void*) beats (void*, size_t). */
5913 {
5916 }
5917 /* At global scope (in C++14 and above) the rules are different:
5919 If deallocation function lookup finds both a usual
5920 deallocation function with only a pointer parameter and a
5921 usual deallocation function with both a pointer parameter
5922 and a size parameter, the function to be called is selected
5923 as follows:
5925 * If the type is complete and if, for the second alternative
5926 (delete array) only, the operand is a pointer to a class
5927 type with a non-trivial destructor or a (possibly
5928 multi-dimensional) array thereof, the function with two
5929 parameters is selected.
5931 * Otherwise, it is unspecified which of the two deallocation
5932 functions is selected. */
5933 else
5934 {
5938 /* We need a cookie to determine the array size. */
5943 }
5944 }
5945 }
5947 /* If we have a matching function, call it. */
5949 {
5952 /* If the FN is a member function, make sure that it is
5953 accessible. */
5956 complain);
5958 /* Core issue 901: It's ok to new a type with deleted delete. */
5963 {
5964 /* The placement args might not be suitable for overload
5965 resolution at this point, so build the call directly. */
5975 }
5976 else
5977 {
5978 tree ret;
5986 }
5987 }
5989 /* [expr.new]
5991 If no unambiguous matching deallocation function can be found,
5992 propagating the exception does not cause the object's memory to
5993 be freed. */
5995 {
5999 alloc_fn);
6001 }
6007 }
6009 /* If the current scope isn't allowed to access DECL along
6010 BASETYPE_PATH, give an error. The most derived class in
6011 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6012 the declaration to use in the error diagnostic. */
6014 bool
6016 tsubst_flags_t complain)
6017 {
6021 {
6023 {
6025 {
6029 }
6031 {
6035 }
6036 else
6037 {
6040 }
6041 }
6043 }
6046 }
6048 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6049 bitwise or of LOOKUP_* values. If any errors are warnings are
6050 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6051 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6052 to NULL. */
6054 static tree
6057 {
6070 else
6073 }
6075 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6076 EXPR is implicitly converted to type TOTYPE.
6077 FN and ARGNUM are used for diagnostics. */
6079 static void
6081 {
6082 /* Issue warnings about peculiar, but valid, uses of NULL. */
6085 {
6086 source_location loc =
6093 else
6096 }
6098 /* Issue warnings if "false" is converted to a NULL pointer */
6101 {
6104 "converting %<false%> to pointer type for argument %P "
6106 else
6109 }
6110 }
6112 /* We gave a diagnostic during a conversion. If this was in the second
6113 standard conversion sequence of a user-defined conversion sequence, say
6114 which user-defined conversion. */
6116 static void
6118 {
6122 {
6126 }
6127 }
6129 /* Perform the conversions in CONVS on the expression EXPR. FN and
6130 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6131 indicates the `this' argument of a method. INNER is nonzero when
6132 being called to continue a conversion chain. It is negative when a
6133 reference binding will be applied, positive otherwise. If
6134 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6135 conversions will be emitted if appropriate. If C_CAST_P is true,
6136 this conversion is coming from a C-style cast; in that case,
6137 conversions to inaccessible bases are permitted. */
6139 static tree
6143 {
6145 diagnostic_t diag_kind;
6161 {
6165 /* Give a helpful error if this is bad because of excess braces. */
6170 {
6176 }
6178 /* Give a helpful error if this is bad because a conversion to bool
6179 from std::nullptr_t requires direct-initialization. */
6187 {
6189 {
6192 totype);
6198 complain);
6202 complain);
6203 else
6209 }
6211 {
6215 complain);
6217 }
6222 complain);
6225 }
6234 }
6240 {
6242 {
6247 /* If we're initializing from {}, it's value-initialization. Note
6248 that under the resolution of core 1630, value-initialization can
6249 use explicit constructors. */
6253 {
6258 {
6261 }
6263 }
6265 /* When converting from an init list we consider explicit
6266 constructors, but actually trying to call one is an error. */
6268 /* Unless this is for direct-list-initialization. */
6270 {
6275 }
6279 /* Set user_conv_p on the argument conversions, so rvalue/base
6280 handling knows not to allow any more UDCs. */
6286 /* If this is a constructor or a function returning an aggr type,
6287 we need to build up a TARGET_EXPR. */
6289 {
6292 /* Remember that this was list-initialization. */
6295 }
6298 }
6301 {
6307 else
6309 }
6314 /* Convert a constant to its underlying value, unless we are
6315 about to bind it to a reference, in which case we need to
6316 leave it as an lvalue. */
6318 {
6321 /* If __null has been converted to an integer type, we do not
6322 want to warn about uses of EXPR as an integer, rather than
6323 as a pointer. */
6325 }
6328 /* We leave bad_p off ck_ambig because overload resolution considers
6329 it valid, it just fails when we try to perform it. So we need to
6330 check complain here, too. */
6332 {
6333 /* Call build_user_type_conversion again for the error. */
6335 complain);
6339 }
6343 {
6344 /* Conversion to std::initializer_list<T>. */
6352 /* Convert all the elements. */
6354 {
6365 }
6366 /* Build up the array. */
6367 elttype = cp_build_qualified_type
6371 /* Take the address explicitly rather than via decay_conversion
6372 to avoid the error about taking the address of a temporary. */
6378 /* Build up the initializer_list object. */
6386 }
6390 {
6399 }
6402 complain);
6409 };
6414 c_cast_p,
6415 complain);
6420 {
6428 /* Else fall through. */
6431 {
6432 /* We are going to bind a reference directly to a base-class
6433 subobject of EXPR. */
6434 /* Build an expression for `*((base*) &expr)'. */
6438 }
6440 /* Copy-initialization where the cv-unqualified version of the source
6441 type is the same class as, or a derived class of, the class of the
6442 destination [is treated as direct-initialization]. [dcl.init] */
6445 /* This conversion is being done in the context of a user-defined
6446 conversion (i.e. the second step of copy-initialization), so
6447 don't allow any more. */
6449 else
6455 /* Copy-list-initialization doesn't actually involve a copy. */
6459 {
6464 }
6469 {
6473 {
6486 else
6493 }
6495 /* If necessary, create a temporary.
6497 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6498 that need temporaries, even when their types are reference
6499 compatible with the type of reference being bound, so the
6500 upcoming call to cp_build_addr_expr doesn't fail. */
6504 {
6505 /* Otherwise, a temporary of type "cv1 T1" is created and
6506 initialized from the initializer expression using the rules
6507 for a non-reference copy-initialization (8.5). */
6516 {
6517 /* If the reference is volatile or non-const, we
6518 cannot create a temporary. */
6525 else
6529 }
6530 /* If the source is a packed field, and we must use a copy
6531 constructor, then building the target expr will require
6532 binding the field to the reference parameter to the
6533 copy constructor, and we'll end up with an infinite
6534 loop. If we can use a bitwise copy, then we'll be
6535 OK. */
6539 {
6543 }
6545 {
6548 }
6550 }
6552 /* Take the address of the thing to which we will bind the
6553 reference. */
6558 /* Convert it to a pointer to the type referred to by the
6559 reference. This will adjust the pointer if a derived to
6560 base conversion is being performed. */
6563 /* Convert the pointer to the desired reference type. */
6565 }
6571 /* Warn about deprecated conversion if appropriate. */
6587 }
6595 else
6599 }
6601 /* ARG is being passed to a varargs function. Perform any conversions
6602 required. Return the converted value. */
6604 tree
6606 {
6607 tree arg_type;
6610 /* [expr.call]
6612 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6613 standard conversions are performed. */
6616 /* [expr.call]
6618 If the argument has integral or enumeration type that is subject
6619 to the integral promotions (_conv.prom_), or a floating point
6620 type that is subject to the floating point promotion
6621 (_conv.fpprom_), the value of the argument is converted to the
6622 promoted type before the call. */
6627 {
6631 "implicit conversion from %qT to %qT when passing "
6635 }
6639 {
6641 {
6643 complain);
6653 }
6654 else
6656 }
6662 /* In a template (or ill-formed code), we can have an incomplete type
6663 even after require_complete_type_sfinae, in which case we don't know
6664 whether it has trivial copy or not. */
6666 {
6667 /* Build up a real lvalue-to-rvalue conversion in case the
6668 copy constructor is trivial but not callable. */
6672 /* [expr.call] 5.2.2/7:
6673 Passing a potentially-evaluated argument of class type (Clause 9)
6674 with a non-trivial copy constructor or a non-trivial destructor
6675 with no corresponding parameter is conditionally-supported, with
6676 implementation-defined semantics.
6678 We support it as pass-by-invisible-reference, just like a normal
6679 value parameter.
6681 If the call appears in the context of a sizeof expression,
6682 it is not potentially-evaluated. */
6686 {
6689 "passing objects of non-trivially-copyable "
6691 arg_type);
6693 }
6694 }
6697 }
6699 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6701 tree
6703 {
6705 {
6709 }
6719 {
6722 }
6726 {
6727 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6728 it as pass by invisible reference. */
6730 "receiving objects of non-trivially-copyable type %q#T "
6736 }
6739 }
6741 /* TYPE has been given to va_arg. Apply the default conversions which
6742 would have happened when passed via ellipsis. Return the promoted
6743 type, or the passed type if there is no change. */
6745 tree
6747 {
6748 tree promote;
6750 /* Perform the array-to-pointer and function-to-pointer
6751 conversions. */
6759 }
6761 /* ARG is a default argument expression being passed to a parameter of
6762 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6763 zero-based argument number. Do any required conversions. Return
6764 the converted value. */
6767 void
6771 void
6775 tree
6777 tsubst_flags_t complain)
6778 {
6780 tree t;
6782 /* See through clones. */
6785 /* Detect recursion. */
6788 {
6792 }
6794 /* If the ARG is an unparsed default argument expression, the
6795 conversion cannot be performed. */
6797 {
6802 }
6809 /* Due to:
6811 [dcl.fct.default]
6813 The names in the expression are bound, and the semantic
6814 constraints are checked, at the point where the default
6815 expressions appears.
6817 we must not perform access checks here. */
6819 /* We must make a copy of ARG, in case subsequent processing
6820 alters any part of it. */
6824 complain);
6831 }
6833 /* Returns the type which will really be used for passing an argument of
6834 type TYPE. */
6836 tree
6838 {
6839 /* Pass classes with copy ctors by invisible reference. */
6841 {
6843 /* There are no other pointers to this temporary. */
6845 }
6853 }
6855 /* Actually perform the appropriate conversion. */
6857 tree
6859 {
6860 tree bitfield_type;
6862 /* If VAL is a bitfield, then -- since it has already been converted
6863 to TYPE -- it cannot have a precision greater than TYPE.
6865 If it has a smaller precision, we must widen it here. For
6866 example, passing "int f:3;" to a function expecting an "int" will
6867 not result in any conversion before this point.
6869 If the precision is the same we must not risk widening. For
6870 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6871 often have type "int", even though the C++ type for the field is
6872 "long long". If the value is being passed to a function
6873 expecting an "int", then no conversions will be required. But,
6874 if we call convert_bitfield_to_declared_type, the bitfield will
6875 be converted to "long long". */
6882 ;
6883 /* Pass classes with copy ctors by invisible reference. */
6893 {
6902 }
6904 }
6906 /* Returns true iff FN is a function with magic varargs, i.e. ones for
6907 which no conversions at all should be done. This is true for some
6908 builtins which don't act like normal functions. */
6910 bool
6912 {
6918 {
6928 }
6931 }
6933 /* Returns the decl of the dispatcher function if FN is a function version. */
6935 tree
6937 {
6947 {
6951 }
6956 }
6958 /* fn is a function version dispatcher that is marked used. Mark all the
6959 semantically identical function versions it will dispatch as used. */
6961 void
6963 {
6980 /* All semantically identical versions are chained. Traverse and mark each
6981 one of them as used. */
6984 {
6987 }
6988 }
6990 /* Build a call to "the copy constructor" for the type of A, even if it
6991 wouldn't be selected by normal overload resolution. Used for
6992 diagnostics. */
6994 static tree
6996 {
7007 }
7009 /* Subroutine of the various build_*_call functions. Overload resolution
7010 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7011 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7012 bitmask of various LOOKUP_* flags which apply to the call itself. */
7014 static tree
7016 {
7024 tree val;
7033 /* In a template, there is no need to perform all of the work that
7034 is normally done. We are only interested in the type of the call
7035 expression, i.e., the return type of the function. Any semantic
7036 errors will be deferred until the template is instantiated. */
7038 {
7040 tree return_type;
7048 else
7049 {
7052 tree arg;
7060 }
7070 }
7072 /* Give any warnings we noticed during overload resolution. */
7074 {
7078 }
7080 /* Make =delete work with SFINAE. */
7085 {
7086 tree access_fn;
7087 /* If FN is a template function, two cases must be considered.
7088 For example:
7090 struct A {
7091 protected:
7092 template <class T> void f();
7093 };
7094 template <class T> struct B {
7095 protected:
7096 void g();
7097 };
7098 struct C : A, B<int> {
7099 using A::f; // #1
7100 using B<int>::g; // #2
7101 };
7103 In case #1 where `A::f' is a member template, DECL_ACCESS is
7104 recorded in the primary template but not in its specialization.
7105 We check access of FN using its primary template.
7107 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7108 because it is a member of class template B, DECL_ACCESS is
7109 recorded in the specialization `B<int>::g'. We cannot use its
7110 primary template because `B<T>::g' and `B<int>::g' may have
7111 different access. */
7115 else
7120 }
7122 /* If we're checking for implicit delete, don't bother with argument
7123 conversions. */
7125 {
7127 {
7131 }
7135 /* Reject bad conversions now. */
7137 /* else continue to get conversion error. */
7138 }
7140 /* N3276 magic doesn't apply to nested calls. */
7144 /* Find maximum size of vector to hold converted arguments. */
7151 /* The implicit parameters to a constructor are not considered by overload
7152 resolution, and must be of the proper type. */
7154 {
7155 tree object_arg;
7157 {
7160 }
7161 else
7162 {
7165 }
7168 /* We should never try to call the abstract constructor. */
7172 {
7176 }
7177 }
7178 /* Bypass access control for 'this' parameter. */
7180 {
7183 ? first_arg
7186 tree converted_arg;
7187 tree base_binfo;
7190 {
7192 {
7197 }
7198 else
7200 }
7202 /* See if the function member or the whole class type is declared
7203 final and the call can be devirtualized. */
7208 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7209 X is called for an object that is not of type X, or of a type
7210 derived from X, the behavior is undefined.
7212 So we can assume that anything passed as 'this' is non-null, and
7213 optimize accordingly. */
7215 /* Convert to the base in which the function was declared. */
7218 arg,
7221 /* Check that the base class is accessible. */
7224 {
7229 else
7231 }
7232 /* If fn was found by a using declaration, the conversion path
7233 will be to the derived class, not the base declaring fn. We
7234 must convert from derived to base. */
7245 else
7249 }
7254 {
7261 /* If the argument is NULL and used to (implicitly) instantiate a
7262 template function (and bind one of the template arguments to
7263 the type of 'long int'), we don't want to warn about passing NULL
7264 to non-pointer argument.
7265 For example, if we have this template function:
7267 template<typename T> void func(T x) {}
7269 we want to warn (when -Wconversion is enabled) in this case:
7271 void foo() {
7272 func<int>(NULL);
7273 }
7275 but not in this case:
7277 void foo() {
7278 func(NULL);
7279 }
7280 */
7287 /* Warn about initializer_list deduction that isn't currently in the
7288 working draft. */
7290 && flag_deduce_init_list
7294 {
7307 {
7315 }
7316 }
7318 conversion_warning
7319 ? complain
7326 else
7328 }
7330 /* Default arguments */
7332 {
7338 complain);
7339 }
7341 /* Ellipsis */
7343 {
7346 /* Do no conversions for magic varargs. */
7351 {
7352 /* Avoid infinite recursion trying to call A(...). */
7354 /* Try to call the actual copy constructor for a good error. */
7357 }
7358 else
7361 }
7368 /* Avoid actually calling copy constructors and copy assignment operators,
7369 if possible. */
7376 /* It's unsafe to elide the constructor when handling
7377 a noexcept-expression, it may evaluate to the wrong
7378 value (c++/53025). */
7380 {
7381 tree targ;
7383 tree fa;
7386 /* Pull out the real argument, disregarding const-correctness. */
7392 {
7397 }
7398 else
7403 else
7406 /* [class.copy]: the copy constructor is implicitly defined even if
7407 the implementation elided its use. */
7409 {
7413 }
7415 /* If we're creating a temp and we already have one, don't create a
7416 new one. If we're not creating a temp but we get one, use
7417 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7418 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7419 temp or an INIT_EXPR otherwise. */
7422 {
7427 }
7429 {
7431 complain));
7435 }
7436 }
7440 {
7441 tree to = stabilize_reference
7448 {
7449 /* Avoid copying empty classes. */
7454 }
7456 {
7459 }
7460 else
7461 {
7462 /* We must only copy the non-tail padding parts. */
7470 build_index_type
7479 }
7482 }
7487 /* FIXME handle trivial default constructor, too. */
7489 /* For calls to a multi-versioned function, overload resolution
7490 returns the function with the highest target priority, that is,
7491 the version that will checked for dispatching first. If this
7492 version is inlinable, a direct call to this version can be made
7493 otherwise the call should go through the dispatcher. */
7498 {
7504 }
7511 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7512 virtual functions can't be constexpr. */
7514 {
7515 tree t;
7522 complain);
7528 else
7531 }
7532 else
7533 {
7537 }
7544 }
7546 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7547 This function performs no overload resolution, conversion, or other
7548 high-level operations. */
7550 tree
7552 tsubst_flags_t complain)
7553 {
7554 tree fndecl;
7557 /* Remember roughly where this call is. */
7564 /* Check that arguments to builtin functions match the expectations. */
7571 /* If it is a built-in array notation function, then the return type of
7572 the function is the element type of the array passed in as array
7573 notation (i.e. the first parameter of the function). */
7575 {
7584 {
7586 {
7589 }
7590 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7591 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7592 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7593 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7594 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7595 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7596 The pre-defined return-type is the correct one. */
7600 }
7601 }
7603 /* Some built-in function calls will be evaluated at compile-time in
7604 fold (). Set optimize to 1 when folding __builtin_constant_p inside
7605 a constexpr function so that fold_builtin_1 doesn't fold it to 0. */
7608 && current_function_decl
7617 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7618 function call is either the operand of a decltype-specifier or the
7619 right operand of a comma operator that is the operand of a
7620 decltype-specifier, a temporary object is not introduced for the
7621 prvalue. The type of the prvalue may be incomplete. */
7623 {
7630 }
7632 }
7636 /* Make an expression which yields the address of the Java interface
7637 method FN. This is achieved by generating a call to libjava's
7638 _Jv_LookupInterfaceMethodIdx(). */
7640 static tree
7642 {
7648 {
7652 java_iface_lookup_fn
7655 }
7657 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7658 This is the first entry in the vtable. */
7660 tf_warning_or_error),
7661 integer_zero_node);
7663 /* Get the java.lang.Class pointer for the interface being called. */
7668 {
7670 iface);
7672 }
7676 /* Determine the itable index of FN. */
7679 {
7684 i++;
7685 }
7690 java_iface_lookup_fn);
7693 }
7695 /* Returns the value to use for the in-charge parameter when making a
7696 call to a function with the indicated NAME.
7698 FIXME:Can't we find a neater way to do this mapping? */
7700 tree
7702 {
7713 /* This function should only be called with one of the names listed
7714 above. */
7717 }
7719 /* Build a call to a constructor, destructor, or an assignment
7720 operator for INSTANCE, an expression with class type. NAME
7721 indicates the special member function to call; *ARGS are the
7722 arguments. ARGS may be NULL. This may change ARGS. BINFO
7723 indicates the base of INSTANCE that is to be passed as the `this'
7724 parameter to the member function called.
7726 FLAGS are the LOOKUP_* flags to use when processing the call.
7728 If NAME indicates a complete object constructor, INSTANCE may be
7729 NULL_TREE. In this case, the caller will call build_cplus_new to
7730 store the newly constructed object into a VAR_DECL. */
7732 tree
7735 {
7736 tree fns;
7737 /* The type of the subobject to be constructed or destroyed. */
7738 tree class_type;
7740 tree ret;
7749 {
7750 /* Resolve the name. */
7755 }
7761 /* Handle the special case where INSTANCE is NULL_TREE. */
7764 else
7765 {
7771 /* Convert to the base class, if necessary. */
7774 {
7776 /* For constructors and destructors, either the base is
7777 non-virtual, or it is virtual but we are doing the
7778 conversion from a constructor or destructor for the
7779 complete object. In either case, we can convert
7780 statically. */
7782 else
7783 /* However, for assignment operators, we must convert
7784 dynamically if the base is virtual. */
7787 }
7788 }
7794 /* When making a call to a constructor or destructor for a subobject
7795 that uses virtual base classes, pass down a pointer to a VTT for
7796 the subobject. */
7800 {
7801 tree vtt;
7802 tree sub_vtt;
7804 /* If the current function is a complete object constructor
7805 or destructor, then we fetch the VTT directly.
7806 Otherwise, we look it up using the VTT we were given. */
7814 current_vtt_parm,
7815 vtt);
7818 else
7822 {
7825 }
7828 }
7833 complain);
7847 }
7849 /* Return the NAME, as a C string. The NAME indicates a function that
7850 is a member of TYPE. *FREE_P is set to true if the caller must
7851 free the memory returned.
7853 Rather than go through all of this, we should simply set the names
7854 of constructors and destructors appropriately, and dispense with
7855 ctor_identifier, dtor_identifier, etc. */
7859 {
7862 /* Assume that we will not allocate memory. */
7864 /* Constructors and destructors are special. */
7866 {
7867 pretty_name
7869 /* For a destructor, add the '~'. */
7873 {
7875 /* Remember that we need to free the memory allocated. */
7877 }
7878 }
7880 {
7883 TFF_PLAIN_IDENTIFIER),
7884 NULL);
7885 /* Remember that we need to free the memory allocated. */
7887 }
7888 else
7892 }
7894 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
7895 be set, upon return, to the function called. ARGS may be NULL.
7896 This may change ARGS. */
7898 static tree
7902 {
7907 tree optype;
7909 tree name;
7912 tree call;
7913 tree fn;
7916 tree orig_instance;
7917 tree orig_fns;
7923 /* We don't know what function we're going to call, yet. */
7932 {
7936 }
7941 /* Dismantle the baselink to collect all the information we need. */
7949 {
7953 }
7964 {
7969 }
7972 /* Under DR 147 A::A() is an invalid constructor call,
7973 not a functional cast. */
7975 {
7985 complain);
7987 }
7989 /* Figure out whether to skip the first argument for the error
7990 message we will display to users if an error occurs. We don't
7991 want to display any compiler-generated arguments. The "this"
7992 pointer hasn't been added yet. However, we must remove the VTT
7993 pointer if this is a call to a base-class constructor or
7994 destructor. */
7997 {
7998 /* Callers should explicitly indicate whether they want to construct
7999 the complete object or just the part without virtual bases. */
8001 /* Similarly for destructors. */
8003 /* Remove the VTT pointer, if present. */
8007 }
8009 /* Process the argument list. */
8011 {
8015 }
8017 /* Consider the object argument to be used even if we end up selecting a
8018 static member function. */
8021 /* It's OK to call destructors and constructors on cv-qualified objects.
8022 Therefore, convert the INSTANCE to the unqualified type, if
8023 necessary. */
8026 {
8028 {
8032 }
8033 }
8037 /* For the overload resolution we need to find the actual `this`
8038 that would be captured if the call turns out to be to a
8039 non-static member function. Do not actually capture it at this
8040 point. */
8042 /* Constructors don't use the enclosing 'this'. */
8044 else
8047 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8050 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8051 initializer, not T({ }). */
8054 {
8061 /* If the initializer list has no elements and T is a class type with
8062 a default constructor, the object is value-initialized. Handle
8063 this here so we don't need to handle it wherever we use
8064 build_special_member_call. */
8067 /* For a user-provided default constructor, use the normal
8068 mechanisms so that protected access works. */
8073 /* If BASETYPE is an aggregate, we need to do aggregate
8074 initialization. */
8076 {
8079 }
8082 {
8088 }
8090 /* Otherwise go ahead with overload resolution. */
8095 }
8096 else
8097 {
8101 }
8106 {
8108 {
8115 else
8116 {
8119 tree arglist;
8130 }
8132 }
8134 }
8135 else
8136 {
8139 {
8142 tree arglist;
8145 {
8153 else
8159 }
8161 }
8162 else
8163 {
8171 {
8172 /* This is not an error, it is runtime undefined
8173 behavior. */
8182 fn);
8183 }
8188 {
8193 {
8194 /* We captured 'this' in the current lambda now that
8195 we know we really need it. */
8197 }
8198 else
8199 {
8202 fn);
8204 }
8205 }
8208 {
8209 /* Optimize away vtable lookup if we know that this
8210 function can't be overridden. We need to check if
8211 the context and the type where we found fn are the same,
8212 actually FN might be defined in a different class
8213 type because of a using-declaration. In this case, we
8214 do not want to perform a non-virtual call. */
8216 && same_type_ignoring_top_level_qualifiers_p
8222 /* Now we know what function is being called. */
8225 /* Build the actual CALL_EXPR. */
8227 /* In an expression of the form `a->f()' where `f' turns
8228 out to be a static member function, `a' is
8229 none-the-less evaluated. */
8238 /* An explicit call of the form "x->~X()" has type
8239 "void". However, on platforms where destructors
8240 return "this" (i.e., those where
8241 targetm.cxx.cdtor_returns_this is true), such calls
8242 will appear to have a return value of pointer type
8243 to the low-level call machinery. We do not want to
8244 change the low-level machinery, since we want to be
8245 able to optimize "delete f()" on such platforms as
8246 "operator delete(~X(f()))" (rather than generating
8247 "t = f(), ~X(t), operator delete (t)"). */
8249 }
8250 }
8251 }
8254 {
8260 {
8263 }
8266 call = (build_min_non_dep_call_vec
8270 orig_args));
8275 }
8277 /* Free all the conversions we allocated. */
8284 }
8286 /* Wrapper for above. */
8288 tree
8292 {
8293 tree ret;
8299 }
8301 /* Returns true iff standard conversion sequence ICS1 is a proper
8302 subsequence of ICS2. */
8304 static bool
8306 {
8307 /* We can assume that a conversion of the same code
8308 between the same types indicates a subsequence since we only get
8309 here if the types we are converting from are the same. */
8316 {
8326 /* At this point, ICS1 cannot be a proper subsequence of
8327 ICS2. We can get a USER_CONV when we are comparing the
8328 second standard conversion sequence of two user conversion
8329 sequences. */
8339 }
8340 }
8342 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8343 be any _TYPE nodes. */
8345 bool
8347 {
8351 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8352 considers every class derived from itself. */
8355 }
8357 /* We build the ICS for an implicit object parameter as a pointer
8358 conversion sequence. However, such a sequence should be compared
8359 as if it were a reference conversion sequence. If ICS is the
8360 implicit conversion sequence for an implicit object parameter,
8361 modify it accordingly. */
8363 static void
8365 {
8367 {
8368 /* [over.match.funcs]
8370 For non-static member functions, the type of the
8371 implicit object parameter is "reference to cv X"
8372 where X is the class of which the function is a
8373 member and cv is the cv-qualification on the member
8374 function declaration. */
8376 tree reference_type;
8378 /* The `this' parameter is a pointer to a class type. Make the
8379 implicit conversion talk about a reference to that same class
8380 type. */
8393 }
8394 }
8396 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8397 and return the initial reference binding conversion. Otherwise,
8398 leave *ICS unchanged and return NULL. */
8402 {
8404 {
8409 }
8412 }
8414 /* Compare two implicit conversion sequences according to the rules set out in
8415 [over.ics.rank]. Return values:
8417 1: ics1 is better than ics2
8418 -1: ics2 is better than ics1
8419 0: ics1 and ics2 are indistinguishable */
8421 static int
8423 {
8424 tree from_type1;
8425 tree from_type2;
8426 tree to_type1;
8427 tree to_type2;
8434 /* REF_BINDING is nonzero if the result of the conversion sequence
8435 is a reference type. In that case REF_CONV is the reference
8436 binding conversion. */
8440 /* Compare badness before stripping the reference conversion. */
8446 /* Handle implicit object parameters. */
8450 /* Handle reference parameters. */
8454 /* List-initialization sequence L1 is a better conversion sequence than
8455 list-initialization sequence L2 if L1 converts to
8456 std::initializer_list<X> for some X and L2 does not. */
8462 /* [over.ics.rank]
8464 When comparing the basic forms of implicit conversion sequences (as
8465 defined in _over.best.ics_)
8467 --a standard conversion sequence (_over.ics.scs_) is a better
8468 conversion sequence than a user-defined conversion sequence
8469 or an ellipsis conversion sequence, and
8471 --a user-defined conversion sequence (_over.ics.user_) is a
8472 better conversion sequence than an ellipsis conversion sequence
8473 (_over.ics.ellipsis_). */
8474 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8475 mismatch. If both ICS are bad, we try to make a decision based on
8476 what would have happened if they'd been good. This is not an
8477 extension, we'll still give an error when we build up the call; this
8478 just helps us give a more helpful error message. */
8488 /* Both conversions are ellipsis conversions. */
8491 /* User-defined conversion sequence U1 is a better conversion sequence
8492 than another user-defined conversion sequence U2 if they contain the
8493 same user-defined conversion operator or constructor and if the sec-
8494 ond standard conversion sequence of U1 is better than the second
8495 standard conversion sequence of U2. */
8497 /* Handle list-conversion with the same code even though it isn't always
8498 ranked as a user-defined conversion and it doesn't have a second
8499 standard conversion sequence; it will still have the desired effect.
8500 Specifically, we need to do the reference binding comparison at the
8501 end of this function. */
8504 {
8520 {
8523 }
8524 else
8525 {
8526 /* For ambiguous or aggregate conversions, use the target type as
8527 a proxy for the conversion function. */
8530 }
8532 /* We can just fall through here, after setting up
8533 FROM_TYPE1 and FROM_TYPE2. */
8536 }
8537 else
8538 {
8542 /* We're dealing with two standard conversion sequences.
8544 [over.ics.rank]
8546 Standard conversion sequence S1 is a better conversion
8547 sequence than standard conversion sequence S2 if
8549 --S1 is a proper subsequence of S2 (comparing the conversion
8550 sequences in the canonical form defined by _over.ics.scs_,
8551 excluding any Lvalue Transformation; the identity
8552 conversion sequence is considered to be a subsequence of
8553 any non-identity conversion sequence */
8564 }
8566 /* One sequence can only be a subsequence of the other if they start with
8567 the same type. They can start with different types when comparing the
8568 second standard conversion sequence in two user-defined conversion
8569 sequences. */
8571 {
8576 }
8578 /* [over.ics.rank]
8580 Or, if not that,
8582 --the rank of S1 is better than the rank of S2 (by the rules
8583 defined below):
8585 Standard conversion sequences are ordered by their ranks: an Exact
8586 Match is a better conversion than a Promotion, which is a better
8587 conversion than a Conversion.
8589 Two conversion sequences with the same rank are indistinguishable
8590 unless one of the following rules applies:
8592 --A conversion that does not a convert a pointer, pointer to member,
8593 or std::nullptr_t to bool is better than one that does.
8595 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8596 so that we do not have to check it explicitly. */
8605 /* A conversion from scalar arithmetic type to complex is worse than a
8606 conversion between scalar arithmetic types. */
8613 {
8616 else
8618 }
8624 {
8629 }
8630 /* The rules for pointers to members A::* are just like the rules
8631 for pointers A*, except opposite: if B is derived from A then
8632 A::* converts to B::*, not vice versa. For that reason, we
8633 switch the from_ and to_ variables here. */
8640 {
8645 }
8650 {
8651 /* This was one of the pointer or pointer-like conversions.
8653 [over.ics.rank]
8655 --If class B is derived directly or indirectly from class A,
8656 conversion of B* to A* is better than conversion of B* to
8657 void*, and conversion of A* to void* is better than
8658 conversion of B* to void*. */
8661 {
8663 deref_from_type2))
8666 deref_from_type1))
8668 }
8671 {
8673 {
8675 {
8677 deref_to_type1))
8679 }
8680 /* We know that DEREF_TO_TYPE1 is `void' here. */
8682 deref_to_type2))
8684 }
8685 }
8688 {
8689 /* [over.ics.rank]
8691 --If class B is derived directly or indirectly from class A
8692 and class C is derived directly or indirectly from B,
8694 --conversion of C* to B* is better than conversion of C* to
8695 A*,
8697 --conversion of B* to A* is better than conversion of C* to
8698 A* */
8700 {
8702 deref_to_type2))
8705 deref_to_type1))
8707 }
8709 {
8711 deref_from_type1))
8714 deref_from_type2))
8716 }
8717 }
8718 }
8721 {
8724 /* [over.ics.rank]
8726 --binding of an expression of type C to a reference of type
8727 B& is better than binding an expression of type C to a
8728 reference of type A&
8730 --conversion of C to B is better than conversion of C to A, */
8733 {
8738 }
8739 }
8742 {
8745 /* [over.ics.rank]
8747 --binding of an expression of type B to a reference of type
8748 A& is better than binding an expression of type C to a
8749 reference of type A&,
8751 --conversion of B to A is better than conversion of C to A */
8754 {
8759 }
8760 }
8762 /* [over.ics.rank]
8764 --S1 and S2 differ only in their qualification conversion and yield
8765 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8766 qualification signature of type T1 is a proper subset of the cv-
8767 qualification signature of type T2 */
8771 {
8775 }
8777 /* [over.ics.rank]
8779 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8780 to an implicit object parameter of a non-static member function
8781 declared without a ref-qualifier, and either S1 binds an lvalue
8782 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8783 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8784 draft standard, 13.3.3.2)
8786 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8787 types to which the references refer are the same type except for
8788 top-level cv-qualifiers, and the type to which the reference
8789 initialized by S2 refers is more cv-qualified than the type to
8790 which the reference initialized by S1 refers.
8792 DR 1328 [over.match.best]: the context is an initialization by
8793 conversion function for direct reference binding (13.3.1.6) of a
8794 reference to function type, the return type of F1 is the same kind of
8795 reference (i.e. lvalue or rvalue) as the reference being initialized,
8796 and the return type of F2 is not. */
8799 {
8806 {
8810 /* Don't prefer a bad conversion that drops cv-quals to a bad
8811 conversion with the wrong rvalueness. */
8815 }
8818 {
8822 {
8823 /* Prefer the one that drops fewer cv-quals. */
8828 }
8830 }
8831 }
8833 /* Neither conversion sequence is better than the other. */
8835 }
8837 /* The source type for this standard conversion sequence. */
8839 static tree
8841 {
8843 {
8848 }
8850 }
8852 /* Note a warning about preferring WINNER to LOSER. We do this by storing
8853 a pointer to LOSER and re-running joust to produce the warning if WINNER
8854 is actually used. */
8856 static void
8858 {
8864 }
8866 /* Compare two candidates for overloading as described in
8867 [over.match.best]. Return values:
8869 1: cand1 is better than cand2
8870 -1: cand2 is better than cand1
8871 0: cand1 and cand2 are indistinguishable */
8873 static int
8875 tsubst_flags_t complain)
8876 {
8882 /* Candidates that involve bad conversions are always worse than those
8883 that don't. */
8889 /* If we have two pseudo-candidates for conversions to the same type,
8890 or two candidates for the same function, arbitrarily pick one. */
8895 /* Prefer a non-deleted function over an implicitly deleted move
8896 constructor or assignment operator. This differs slightly from the
8897 wording for issue 1402 (which says the move op is ignored by overload
8898 resolution), but this way produces better error messages. */
8902 {
8909 }
8911 /* a viable function F1
8912 is defined to be a better function than another viable function F2 if
8913 for all arguments i, ICSi(F1) is not a worse conversion sequence than
8914 ICSi(F2), and then */
8916 /* for some argument j, ICSj(F1) is a better conversion sequence than
8917 ICSj(F2) */
8919 /* For comparing static and non-static member functions, we ignore
8920 the implicit object parameter of the non-static function. The
8921 standard says to pretend that the static function has an object
8922 parm, but that won't work with operator overloading. */
8925 {
8931 /* We're comparing a near-match list constructor and a near-match
8932 non-list constructor. Just treat them as unordered. */
8939 else
8940 {
8943 }
8944 }
8947 {
8953 {
8955 && warn_sign_promo
8967 {
8974 else
8979 {
8983 }
8984 else
8986 }
8989 {
8992 }
8994 }
8995 }
8997 /* warn about confusing overload resolution for user-defined conversions,
8998 either between a constructor and a conversion op, or between two
8999 conversion ops. */
9004 {
9010 else
9013 /* We don't want to complain about `X::operator T1 ()'
9014 beating `X::operator T2 () const', when T2 is a no less
9015 cv-qualified version of T1. */
9018 {
9023 {
9026 }
9029 }
9030 else
9036 {
9043 {
9045 }
9046 }
9047 else
9049 }
9054 /* DR 495 moved this tiebreaker above the template ones. */
9055 /* or, if not that,
9056 the context is an initialization by user-defined conversion (see
9057 _dcl.init_ and _over.match.user_) and the standard conversion
9058 sequence from the return type of F1 to the destination type (i.e.,
9059 the type of the entity being initialized) is a better conversion
9060 sequence than the standard conversion sequence from the return type
9061 of F2 to the destination type. */
9064 {
9068 }
9070 /* or, if not that,
9071 F1 is a non-template function and F2 is a template function
9072 specialization. */
9079 /* or, if not that,
9080 F1 and F2 are template functions and the function template for F1 is
9081 more specialized than the template for F2 according to the partial
9082 ordering rules. */
9085 {
9086 winner = more_specialized_fn
9089 /* [temp.func.order]: The presence of unused ellipsis and default
9090 arguments has no effect on the partial ordering of function
9091 templates. add_function_candidate() will not have
9092 counted the "this" argument for constructors. */
9096 }
9098 /* Check whether we can discard a builtin candidate, either because we
9099 have two identical ones or matching builtin and non-builtin candidates.
9101 (Pedantically in the latter case the builtin which matched the user
9102 function should not be added to the overload set, but we spot it here.
9104 [over.match.oper]
9105 ... the builtin candidates include ...
9106 - do not have the same parameter type list as any non-template
9107 non-member candidate. */
9110 {
9116 {
9118 /* Two built-in candidates; arbitrarily pick one. */
9121 /* cand1 is built-in; prefer cand2. */
9123 else
9124 /* cand2 is built-in; prefer cand1. */
9126 }
9127 }
9129 /* For candidates of a multi-versioned function, make the version with
9130 the highest priority win. This version will be checked for dispatching
9131 first. If this version can be inlined into the caller, the front-end
9132 will simply make a direct call to this function. */
9138 {
9144 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9145 is possible that cand1->fn and cand2->fn are function versions but of
9146 different functions. Check types to see if they are versions of the same
9147 function. */
9150 {
9151 /* Always make the version with the higher priority, more
9152 specialized, win. */
9156 else
9158 }
9159 }
9161 /* If the two function declarations represent the same function (this can
9162 happen with declarations in multiple scopes and arg-dependent lookup),
9163 arbitrarily choose one. But first make sure the default args we're
9164 using match. */
9167 {
9174 {
9175 /* Don't crash if the fn is variadic. */
9180 }
9188 {
9191 {
9193 {
9195 {
9197 "default argument mismatch in "
9199 {
9204 }
9205 }
9206 else
9208 }
9209 else
9212 }
9215 }
9218 }
9220 tweak:
9222 /* Extension: If the worst conversion for one candidate is worse than the
9223 worst conversion for the other, take the first. */
9225 {
9230 {
9235 }
9241 {
9242 /* Don't choose a deleted function over ambiguity. */
9246 {
9248 "ISO C++ says that these are ambiguous, even "
9249 "though the worst conversion for the first is better than "
9253 }
9254 else
9257 }
9258 }
9262 }
9264 /* Given a list of candidates for overloading, find the best one, if any.
9265 This algorithm has a worst case of O(2n) (winner is last), and a best
9266 case of O(n/2) (totally ambiguous); much better than a sorting
9267 algorithm. */
9271 {
9276 /* Walk through the list once, comparing each current champ to the next
9277 candidate, knocking out a candidate or two with each comparison. */
9280 {
9284 else
9285 {
9287 {
9292 }
9293 else
9294 {
9297 }
9300 }
9301 }
9303 /* Make sure the champ is better than all the candidates it hasn't yet
9304 been compared to. */
9307 challenger != champ
9310 {
9314 }
9317 }
9319 /* Returns nonzero if things of type FROM can be converted to TO. */
9321 bool
9323 {
9325 /* implicit_conversion only considers user-defined conversions
9326 if it has an expression for the call argument list. */
9330 }
9332 /* Returns nonzero if things of type FROM can be converted to TO with a
9333 standard conversion. */
9335 bool
9337 {
9339 }
9341 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9343 bool
9345 tsubst_flags_t complain)
9346 {
9351 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9353 /* We want to discard any access checks done for this test,
9354 as we might not be in the appropriate access context and
9355 we'll do the check again when we actually perform the
9356 conversion. */
9363 /* Discard the access checks now. */
9365 /* Free all the conversions we allocated. */
9369 }
9371 /* Like can_convert_arg, but allows dubious conversions as well. */
9373 bool
9375 tsubst_flags_t complain)
9376 {
9380 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9382 /* Try to perform the conversion. */
9385 /* Free all the conversions we allocated. */
9389 }
9391 /* Convert EXPR to TYPE. Return the converted expression.
9393 Note that we allow bad conversions here because by the time we get to
9394 this point we are committed to doing the conversion. If we end up
9395 doing a bad conversion, convert_like will complain. */
9397 tree
9400 {
9408 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9416 {
9418 {
9419 /* If expr has unknown type, then it is an overloaded function.
9420 Call instantiate_type to get good error messages. */
9425 else
9428 }
9430 }
9432 {
9433 /* In a template, we are only concerned about determining the
9434 type of non-dependent expressions, so we do not have to
9435 perform the actual conversion. But for initializers, we
9436 need to be able to perform it at instantiation
9437 (or instantiate_non_dependent_expr) time. */
9441 }
9442 else
9445 /* Free all the conversions we allocated. */
9449 }
9451 tree
9453 {
9455 LOOKUP_IMPLICIT);
9456 }
9458 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9459 permitted. If the conversion is valid, the converted expression is
9460 returned. Otherwise, NULL_TREE is returned, except in the case
9461 that TYPE is a class type; in that case, an error is issued. If
9462 C_CAST_P is true, then this direct-initialization is taking
9463 place as part of a static_cast being attempted as part of a C-style
9464 cast. */
9466 tree
9468 tree expr,
9470 tsubst_flags_t complain)
9471 {
9477 /* [dcl.init]
9479 If the destination type is a (possibly cv-qualified) class type:
9481 -- If the initialization is direct-initialization ...,
9482 constructors are considered. ... If no constructor applies, or
9483 the overload resolution is ambiguous, the initialization is
9484 ill-formed. */
9486 {
9492 }
9494 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9498 c_cast_p,
9502 else
9505 c_cast_p,
9506 complain);
9508 /* Free all the conversions we allocated. */
9512 }
9514 /* When initializing a reference that lasts longer than a full-expression,
9515 this special rule applies:
9517 [class.temporary]
9519 The temporary to which the reference is bound or the temporary
9520 that is the complete object to which the reference is bound
9521 persists for the lifetime of the reference.
9523 The temporaries created during the evaluation of the expression
9524 initializing the reference, except the temporary to which the
9525 reference is bound, are destroyed at the end of the
9526 full-expression in which they are created.
9528 In that case, we store the converted expression into a new
9529 VAR_DECL in a new scope.
9531 However, we want to be careful not to create temporaries when
9532 they are not required. For example, given:
9534 struct B {};
9535 struct D : public B {};
9536 D f();
9537 const B& b = f();
9539 there is no need to copy the return value from "f"; we can just
9540 extend its lifetime. Similarly, given:
9542 struct S {};
9543 struct T { operator S(); };
9544 T t;
9545 const S& s = t;
9547 we can extend the lifetime of the return value of the conversion
9548 operator.
9550 The next several functions are involved in this lifetime extension. */
9552 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9553 reference is being bound to a temporary. Create and return a new
9554 VAR_DECL with the indicated TYPE; this variable will store the value to
9555 which the reference is bound. */
9557 tree
9559 {
9560 tree var;
9562 /* Create the variable. */
9565 /* Register the variable. */
9568 {
9569 /* Namespace-scope or local static; give it a mangled name. */
9570 /* FIXME share comdat with decl? */
9571 tree name;
9580 }
9581 else
9582 /* Create a new cleanup level if necessary. */
9586 }
9588 /* EXPR is the initializer for a variable DECL of reference or
9589 std::initializer_list type. Create, push and return a new VAR_DECL
9590 for the initializer so that it will live as long as DECL. Any
9591 cleanup for the new variable is returned through CLEANUP, and the
9592 code to initialize the new variable is returned through INITP. */
9594 static tree
9597 {
9598 tree init;
9599 tree type;
9600 tree var;
9602 /* Create the temporary variable. */
9606 /* If the rvalue is the result of a function call it will be
9607 a TARGET_EXPR. If it is some other construct (such as a
9608 member access expression where the underlying object is
9609 itself the result of a function call), turn it into a
9610 TARGET_EXPR here. It is important that EXPR be a
9611 TARGET_EXPR below since otherwise the INIT_EXPR will
9612 attempt to make a bitwise copy of EXPR to initialize
9613 VAR. */
9619 {
9623 }
9625 /* Recursively extend temps in this initializer. */
9629 /* Any reference temp has a non-trivial initializer. */
9632 /* If the initializer is constant, put it in DECL_INITIAL so we get
9633 static initialization and use in constant expressions. */
9636 {
9638 {
9639 /* 5.19 says that a constant expression can include an
9640 lvalue-rvalue conversion applied to "a glvalue of literal type
9641 that refers to a non-volatile temporary object initialized
9642 with a constant expression". Rather than try to communicate
9643 that this VAR_DECL is a temporary, just mark it constexpr.
9645 Currently this is only useful for initializer_list temporaries,
9646 since reference vars can't appear in constant expressions. */
9650 }
9653 }
9654 else
9655 /* Create the INIT_EXPR that will initialize the temporary
9656 variable. */
9659 {
9664 else
9665 {
9669 }
9671 /* We must be careful to destroy the temporary only
9672 after its initialization has taken place. If the
9673 initialization throws an exception, then the
9674 destructor should not be run. We cannot simply
9675 transform INIT into something like:
9677 (INIT, ({ CLEANUP_STMT; }))
9679 because emit_local_var always treats the
9680 initializer as a full-expression. Thus, the
9681 destructor would run too early; it would run at the
9682 end of initializing the reference variable, rather
9683 than at the end of the block enclosing the
9684 reference variable.
9686 The solution is to pass back a cleanup expression
9687 which the caller is responsible for attaching to
9688 the statement tree. */
9689 }
9690 else
9691 {
9694 {
9697 tls_aggregates);
9698 else
9700 static_aggregates);
9701 }
9702 else
9703 /* Check whether the dtor is callable. */
9705 }
9706 /* Avoid -Wunused-variable warning (c++/38958). */
9713 }
9715 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9716 initializing a variable of that TYPE. */
9718 tree
9721 {
9729 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9735 {
9737 {
9746 else
9750 }
9752 }
9755 /* Perform the conversion. */
9758 /* We gave an error in build_user_type_conversion_1. */
9760 else
9763 /* Free all the conversions we allocated. */
9767 }
9769 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9770 which is bound either to a reference or a std::initializer_list. */
9772 static tree
9774 {
9779 {
9783 }
9786 /* Deal with binding to a subobject. */
9790 {
9798 }
9800 }
9802 /* INIT is part of the initializer for DECL. If there are any
9803 reference or initializer lists being initialized, extend their
9804 lifetime to match that of DECL. */
9806 tree
9808 {
9815 {
9816 /* The temporary array underlying a std::initializer_list
9817 is handled like a reference temporary. */
9822 {
9826 }
9827 }
9829 {
9835 }
9838 }
9840 /* Returns true iff an initializer for TYPE could contain temporaries that
9841 need to be extended because they are bound to references or
9842 std::initializer_list. */
9844 bool
9846 {
9851 {
9858 }
9860 }
9862 /* Returns true iff TYPE is some variant of std::initializer_list. */
9864 bool
9866 {
9867 /* Look through typedefs. */
9876 }
9878 /* Returns true iff DECL is a list constructor: i.e. a constructor which
9879 will accept an argument list of a single std::initializer_list<T>. */
9881 bool
9883 {
9885 tree arg;
9897 /* There are more non-defaulted parms. */
9901 }