| blob | 2f0c53a739178ad2c371ec936ca0dd1ae6538d06 |
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. */
55 /* The various kinds of conversion. */
58 ck_identity,
59 ck_lvalue,
60 ck_qual,
61 ck_std,
62 ck_ptr,
63 ck_pmem,
64 ck_base,
65 ck_ref_bind,
66 ck_user,
67 ck_ambig,
68 ck_list,
69 ck_aggr,
70 ck_rvalue
73 /* The rank of the conversion. Order of the enumerals matters; better
74 conversions should come earlier in the list. */
77 cr_identity,
78 cr_exact,
79 cr_promotion,
80 cr_std,
81 cr_pbool,
82 cr_user,
83 cr_ellipsis,
84 cr_bad
87 /* An implicit conversion sequence, in the sense of [over.best.ics].
88 The first conversion to be performed is at the end of the chain.
89 That conversion is always a cr_identity conversion. */
93 /* The kind of conversion represented by this step. */
94 conversion_kind kind;
95 /* The rank of this conversion. */
96 conversion_rank rank;
100 /* True if this conversion would be permitted with a bending of
101 language standards, e.g. disregarding pointer qualifiers or
102 converting integers to pointers. */
104 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
105 temporary should be created to hold the result of the
106 conversion. */
108 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
109 from a pointer-to-derived to pointer-to-base is being performed. */
111 /* If KIND is ck_ref_bind, true when either an lvalue reference is
112 being bound to an lvalue expression or an rvalue reference is
113 being bound to an rvalue expression. If KIND is ck_rvalue,
114 true when we should treat an lvalue as an rvalue (12.8p33). If
115 KIND is ck_base, always false. */
118 /* The type of the expression resulting from the conversion. */
119 tree type;
121 /* The next conversion in the chain. Since the conversions are
122 arranged from outermost to innermost, the NEXT conversion will
123 actually be performed before this conversion. This variant is
124 used only when KIND is neither ck_identity, ck_ambig nor
125 ck_list. Please use the next_conversion function instead
126 of using this field directly. */
128 /* The expression at the beginning of the conversion chain. This
129 variant is used only if KIND is ck_identity or ck_ambig. */
130 tree expr;
131 /* The array of conversions for an initializer_list, so this
132 variant is used only when KIN D is ck_list. */
135 /* The function candidate corresponding to this conversion
136 sequence. This field is only used if KIND is ck_user. */
138 };
140 #define CONVERSION_RANK(NODE) \
141 ((NODE)->bad_p ? cr_bad \
142 : (NODE)->ellipsis_p ? cr_ellipsis \
143 : (NODE)->user_conv_p ? cr_user \
144 : (NODE)->rank)
146 #define BAD_CONVERSION_RANK(NODE) \
147 ((NODE)->ellipsis_p ? cr_ellipsis \
148 : (NODE)->user_conv_p ? cr_user \
149 : (NODE)->rank)
158 tsubst_flags_t);
162 #define convert_like(CONV, EXPR, COMPLAIN) \
163 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
166 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
167 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
175 tsubst_flags_t);
190 static void add_builtin_candidates
193 static void add_builtin_candidate
197 static void build_builtin_candidate
207 tsubst_flags_t);
210 tsubst_flags_t);
230 tsubst_flags_t);
234 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
235 NAME can take many forms... */
237 bool
239 {
240 /* Just accept something we've already complained about. */
249 {
255 else
257 }
258 else
259 {
260 /* In the case of:
262 template <class T> struct S { ~S(); };
263 int i;
264 i.~S();
266 NAME will be a class template. */
269 }
274 }
276 /* We want the address of a function or method. We avoid creating a
277 pointer-to-member function. */
279 tree
281 {
284 /* We have to do these by hand to avoid real pointer to member
285 functions. */
287 {
289 {
293 complain);
294 }
296 }
297 else
301 }
303 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
304 POINTER_TYPE to those. Note, pointer to member function types
305 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
306 two variants. build_call_a is the primitive taking an array of
307 arguments, while build_call_n is a wrapper that handles varargs. */
309 tree
311 {
314 else
315 {
325 }
326 }
328 /* Update various flags in cfun and the call itself based on what is being
329 called. Split out of build_call_a so that bot_manip can use it too. */
331 void
333 {
337 /* We check both the decl and the type; a function may be known not to
338 throw without being declared throw(). */
352 }
354 tree
356 {
357 tree decl;
358 tree result_type;
359 tree fntype;
369 /* An rvalue has no cv-qualifiers. */
380 {
381 /* We invoke build_call directly for several library
382 functions. These may have been declared normally if
383 we're building libgcc, so we can't just check
384 DECL_ARTIFICIAL. */
389 }
395 /* Don't pass empty class objects by value. This is useful
396 for tags in STL, which are used to control overload resolution.
397 We don't need to handle other cases of copying empty classes. */
400 {
404 {
408 }
409 }
412 }
414 /* New overloading code. */
422 };
424 /* Information for providing diagnostics about why overloading failed. */
427 rr_none,
428 rr_arity,
429 rr_explicit_conversion,
430 rr_template_conversion,
431 rr_arg_conversion,
432 rr_bad_arg_conversion,
433 rr_template_unification,
434 rr_invalid_copy
435 };
438 /* The index of the argument, 0-based. */
440 /* The actual argument or its type. */
441 tree from;
442 /* The type of the parameter. */
443 tree to_type;
444 };
449 /* Information about an arity mismatch. */
451 /* The expected number of arguments. */
453 /* The actual number of arguments in the call. */
455 /* Whether the call was a varargs call. */
458 /* Information about an argument conversion mismatch. */
460 /* Same, but for bad argument conversions. */
462 /* Information about template unification failures. These are the
463 parameters passed to fn_type_unification. */
465 tree tmpl;
466 tree explicit_targs;
470 tree return_type;
471 unification_kind_t strict;
474 /* Information about template instantiation failures. These are the
475 parameters passed to instantiate_template. */
477 tree tmpl;
478 tree targs;
481 };
484 /* The FUNCTION_DECL that will be called if this candidate is
485 selected by overload resolution. */
486 tree fn;
487 /* If not NULL_TREE, the first argument to use when calling this
488 function. */
489 tree first_arg;
490 /* The rest of the arguments to use when calling this function. If
491 there are no further arguments this may be NULL or it may be an
492 empty vector. */
494 /* The implicit conversion sequences for each of the arguments to
495 FN. */
497 /* The number of implicit conversion sequences. */
499 /* If FN is a user-defined conversion, the standard conversion
500 sequence from the type returned by FN to the desired destination
501 type. */
504 /* If FN is a member function, the binfo indicating the path used to
505 qualify the name of FN at the call site. This path is used to
506 determine whether or not FN is accessible if it is selected by
507 overload resolution. The DECL_CONTEXT of FN will always be a
508 (possibly improper) base of this binfo. */
509 tree access_path;
510 /* If FN is a non-static member function, the binfo indicating the
511 subobject to which the `this' pointer should be converted if FN
512 is selected by overload resolution. The type pointed to by
513 the `this' pointer must correspond to the most derived class
514 indicated by the CONVERSION_PATH. */
515 tree conversion_path;
516 tree template_decl;
517 tree explicit_targs;
522 /* The flags active in add_candidate. */
524 };
526 /* Returns true iff T is a null pointer constant in the sense of
527 [conv.ptr]. */
529 bool
531 {
532 /* [conv.ptr]
534 A null pointer constant is an integral constant expression
535 (_expr.const_) rvalue of integer type that evaluates to zero or
536 an rvalue of type std::nullptr_t. */
540 {
541 /* Core issue 903 says only literal 0 is a null pointer constant. */
547 }
549 }
551 /* Returns true iff T is a null member pointer value (4.11). */
553 bool
555 {
564 else
566 }
568 /* Returns nonzero if PARMLIST consists of only default parms,
569 ellipsis, and/or undeduced parameter packs. */
571 bool
573 {
580 }
582 /* Allocate N bytes of memory from the conversion obstack. The memory
583 is zeroed before being returned. */
587 {
590 {
593 }
597 }
599 /* Allocate rejection reasons. */
603 {
608 }
612 {
618 }
622 {
629 }
633 {
640 }
644 {
650 }
654 {
660 }
667 {
674 /* Copy args to our own storage. */
682 }
686 {
688 }
692 {
695 }
697 /* Dynamically allocate a conversion. */
701 {
706 }
708 #ifdef ENABLE_CHECKING
710 /* Make sure that all memory on the conversion obstack has been
711 freed. */
713 void
715 {
719 }
723 /* Dynamically allocate an array of N conversions. */
727 {
729 }
733 {
737 /* Note that the caller is responsible for filling in t->cand for
738 user-defined conversions. */
744 {
760 }
766 }
768 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
769 specialization of std::initializer_list<T>, if such a conversion is
770 possible. */
774 {
780 tree val;
782 /* Within a list-initialization we can have more user-defined
783 conversions. */
785 /* But no narrowing conversions. */
788 /* Can't make an array of these types. */
795 {
796 conversion *sub
803 }
811 {
819 }
822 }
824 /* Return the next conversion of the conversion chain (if applicable),
825 or NULL otherwise. Please use this function instead of directly
826 accessing fields of struct conversion. */
830 {
837 }
839 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
840 is a valid aggregate initializer for array type ATYPE. */
842 static bool
844 {
848 {
854 else
856 complain);
859 }
861 }
863 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
864 aggregate class, if such a conversion is possible. */
868 {
878 /* The conversions within the init-list aren't affected by the enclosing
879 context; they're always simple copy-initialization. */
883 {
885 tree val;
891 /* Value-initialization of reference is ill-formed. */
893 else
894 {
898 }
904 else
906 complain);
913 }
925 }
927 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
928 array type, if such a conversion is possible. */
932 {
937 tree val;
942 /* We might need to propagate the size from the element to the array. */
947 {
951 }
956 {
957 conversion *sub
969 }
978 }
980 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
981 complex type, if such a conversion is possible. */
985 tsubst_flags_t complain)
986 {
991 tree val;
1002 {
1003 conversion *sub
1015 }
1024 }
1026 /* Build a representation of the identity conversion from EXPR to
1027 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1031 {
1039 }
1041 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1042 were multiple user-defined conversions to accomplish the job.
1043 Build a conversion that indicates that ambiguity. */
1047 {
1055 }
1057 tree
1059 {
1063 }
1065 /* Returns the standard conversion path (see [conv]) from type FROM to type
1066 TO, if any. For proper handling of null pointer constants, you must
1067 also pass the expression EXPR to convert from. If C_CAST_P is true,
1068 this conversion is coming from a C-style cast. */
1073 {
1077 tree qualified_to;
1081 {
1084 }
1090 {
1092 {
1098 }
1100 {
1101 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1104 }
1105 }
1112 {
1116 }
1118 {
1120 {
1121 tree bitfield_type;
1124 {
1127 }
1128 }
1132 }
1134 /* Allow conversion between `__complex__' data types. */
1136 {
1137 /* The standard conversion sequence to convert FROM to TO is
1138 the standard conversion sequence to perform componentwise
1139 conversion. */
1144 {
1147 }
1148 else
1152 }
1155 {
1159 }
1161 /* [conv.ptr]
1162 A null pointer constant can be converted to a pointer type; ... A
1163 null pointer constant of integral type can be converted to an
1164 rvalue of type std::nullptr_t. */
1172 {
1173 /* For backwards brain damage compatibility, allow interconversion of
1174 pointers and integers with a pedwarn. */
1177 }
1179 {
1180 /* For backwards brain damage compatibility, allow interconversion of
1181 enums and integers with a pedwarn. */
1184 }
1187 {
1188 tree to_pointee;
1189 tree from_pointee;
1194 ;
1198 {
1200 /* Don't try to apply restrict to void. */
1202 from = build_pointer_type
1205 }
1207 {
1212 && (same_type_ignoring_top_level_qualifiers_p
1215 {
1219 }
1222 }
1225 /* [conv.ptr]
1227 An rvalue of type "pointer to cv D," where D is a
1228 class type, can be converted to an rvalue of type
1229 "pointer to cv B," where B is a base class (clause
1230 _class.derived_) of D. If B is an inaccessible
1231 (clause _class.access_) or ambiguous
1232 (_class.member.lookup_) base class of D, a program
1233 that necessitates this conversion is ill-formed.
1234 Therefore, we use DERIVED_FROM_P, and do not check
1235 access or uniqueness. */
1237 {
1238 from =
1244 }
1247 {
1250 }
1251 else
1252 {
1255 }
1260 /* In a C-style cast, we ignore CV-qualification because we
1261 are allowed to perform a static_cast followed by a
1262 const_cast. */
1267 /* converting from string constant to char *. */
1269 /* Allow conversions among compatible ObjC pointer types (base
1270 conversions have been already handled above). */
1275 {
1278 }
1279 else
1283 }
1285 {
1297 tbase,
1303 }
1305 {
1306 /* [conv.bool]
1308 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1309 to member type can be converted to a prvalue of type bool. ...
1310 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1311 std::nullptr_t can be converted to a prvalue of type bool; */
1317 {
1328 }
1331 }
1332 /* We don't check for ENUMERAL_TYPE here because there are no standard
1333 conversions to enum type. */
1334 /* As an extension, allow conversion to complex type. */
1336 {
1343 /* Give this a better rank if it's a promotion. */
1347 }
1353 {
1357 /* The derived-to-base conversion indicates the initialization
1358 of a parameter with base type from an object of a derived
1359 type. A temporary object is created to hold the result of
1360 the conversion unless we're binding directly to a reference. */
1362 }
1363 else
1370 }
1372 /* Returns nonzero if T1 is reference-related to T2. */
1374 bool
1376 {
1383 /* [dcl.init.ref]
1385 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1386 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1387 of T2. */
1391 }
1393 /* Returns nonzero if T1 is reference-compatible with T2. */
1395 static bool
1397 {
1398 /* [dcl.init.ref]
1400 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1401 reference-related to T2 and cv1 is the same cv-qualification as,
1402 or greater cv-qualification than, cv2. */
1405 }
1407 /* A reference of the indicated TYPE is being bound directly to the
1408 expression represented by the implicit conversion sequence CONV.
1409 Return a conversion sequence for this binding. */
1413 {
1414 tree t;
1421 /* [over.ics.rank]
1423 When a parameter of reference type binds directly
1424 (_dcl.init.ref_) to an argument expression, the implicit
1425 conversion sequence is the identity conversion, unless the
1426 argument expression has a type that is a derived class of the
1427 parameter type, in which case the implicit conversion sequence is
1428 a derived-to-base Conversion.
1430 If the parameter binds directly to the result of applying a
1431 conversion function to the argument expression, the implicit
1432 conversion sequence is a user-defined conversion sequence
1433 (_over.ics.user_), with the second standard conversion sequence
1434 either an identity conversion or, if the conversion function
1435 returns an entity of a type that is a derived class of the
1436 parameter type, a derived-to-base conversion. */
1438 {
1439 /* Represent the derived-to-base conversion. */
1441 /* We will actually be binding to the base-class subobject in
1442 the derived class, so we mark this conversion appropriately.
1443 That way, convert_like knows not to generate a temporary. */
1445 }
1447 }
1449 /* Returns the conversion path from type FROM to reference type TO for
1450 purposes of reference binding. For lvalue binding, either pass a
1451 reference type to FROM or an lvalue expression to EXPR. If the
1452 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1453 the conversion returned. If C_CAST_P is true, this
1454 conversion is coming from a C-style cast. */
1458 tsubst_flags_t complain)
1459 {
1463 tree tfrom;
1466 cp_lvalue_kind gl_kind;
1470 {
1475 }
1478 {
1480 /* DR 1288: Otherwise, if the initializer list has a single element
1481 of type E and ... [T's] referenced type is reference-related to E,
1482 the object or reference is initialized from that element... */
1484 {
1490 {
1494 }
1495 }
1496 /* Otherwise, if T is a reference type, a prvalue temporary of the
1497 type referenced by T is copy-list-initialized or
1498 direct-list-initialized, depending on the kind of initialization
1499 for the reference, and the reference is bound to that temporary. */
1502 skip:;
1503 }
1506 {
1511 else
1513 }
1515 {
1518 /* A class prvalue is not a glvalue. */
1520 }
1521 else
1529 /* Figure out whether or not the types are reference-related and
1530 reference compatible. We have do do this after stripping
1531 references from FROM. */
1533 /* If this is a C cast, first convert to an appropriately qualified
1534 type, so that we can later do a const_cast to the desired type. */
1540 /* Directly bind reference when target expression's type is compatible with
1541 the reference and expression is an lvalue. In DR391, the wording in
1542 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1543 const and rvalue references to rvalues of compatible class type.
1544 We should also do direct bindings for non-class xvalues. */
1546 && (gl_kind
1550 {
1551 /* [dcl.init.ref]
1553 If the initializer expression
1555 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1556 is reference-compatible with "cv2 T2,"
1558 the reference is bound directly to the initializer expression
1559 lvalue.
1561 [...]
1562 If the initializer expression is an rvalue, with T2 a class type,
1563 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1564 is bound to the object represented by the rvalue or to a sub-object
1565 within that object. */
1571 /* The top-level caller requested that we pretend that the lvalue
1572 be treated as an rvalue. */
1575 /* Handle rvalue reference to function properly. */
1576 conv->rvaluedness_matches_p
1578 else
1579 conv->rvaluedness_matches_p
1584 /* For the purposes of overload resolution, we ignore the fact
1585 this expression is a bitfield or packed field. (In particular,
1586 [over.ics.ref] says specifically that a function with a
1587 non-const reference parameter is viable even if the
1588 argument is a bitfield.)
1590 However, when we actually call the function we must create
1591 a temporary to which to bind the reference. If the
1592 reference is volatile, or isn't const, then we cannot make
1593 a temporary, so we just issue an error when the conversion
1594 actually occurs. */
1597 /* Don't allow binding of lvalues (other than function lvalues) to
1598 rvalue references. */
1604 /* Nor the reverse. */
1615 }
1616 /* [class.conv.fct] A conversion function is never used to convert a
1617 (possibly cv-qualified) object to the (possibly cv-qualified) same
1618 object type (or a reference to it), to a (possibly cv-qualified) base
1619 class of that type (or a reference to it).... */
1622 {
1623 /* [dcl.init.ref]
1625 If the initializer expression
1627 -- has a class type (i.e., T2 is a class type) can be
1628 implicitly converted to an lvalue of type "cv3 T3," where
1629 "cv1 T1" is reference-compatible with "cv3 T3". (this
1630 conversion is selected by enumerating the applicable
1631 conversion functions (_over.match.ref_) and choosing the
1632 best one through overload resolution. (_over.match_).
1634 the reference is bound to the lvalue result of the conversion
1635 in the second case. */
1637 complain);
1640 }
1642 /* From this point on, we conceptually need temporaries, even if we
1643 elide them. Only the cases above are "direct bindings". */
1647 /* [over.ics.rank]
1649 When a parameter of reference type is not bound directly to an
1650 argument expression, the conversion sequence is the one required
1651 to convert the argument expression to the underlying type of the
1652 reference according to _over.best.ics_. Conceptually, this
1653 conversion sequence corresponds to copy-initializing a temporary
1654 of the underlying type with the argument expression. Any
1655 difference in top-level cv-qualification is subsumed by the
1656 initialization itself and does not constitute a conversion. */
1658 /* [dcl.init.ref]
1660 Otherwise, the reference shall be an lvalue reference to a
1661 non-volatile const type, or the reference shall be an rvalue
1662 reference.
1664 We try below to treat this as a bad conversion to improve diagnostics,
1665 but if TO is an incomplete class, we need to reject this conversion
1666 now to avoid unnecessary instantiation. */
1671 /* We're generating a temporary now, but don't bind any more in the
1672 conversion (specifically, don't slice the temporary returned by a
1673 conversion operator). */
1676 /* Core issue 899: When [copy-]initializing a temporary to be bound
1677 to the first parameter of a copy constructor (12.8) called with
1678 a single argument in the context of direct-initialization,
1679 explicit conversion functions are also considered.
1681 So don't set LOOKUP_ONLYCONVERTING in that case. */
1692 {
1693 /* If initializing the temporary used a conversion function,
1694 recalculate the second conversion sequence. */
1698 {
1701 conversion *new_second
1707 }
1708 }
1711 /* This reference binding, unlike those above, requires the
1712 creation of a temporary. */
1716 /* [dcl.init.ref]
1718 Otherwise, the reference shall be an lvalue reference to a
1719 non-volatile const type, or the reference shall be an rvalue
1720 reference. */
1724 /* [dcl.init.ref]
1726 Otherwise, a temporary of type "cv1 T1" is created and
1727 initialized from the initializer expression using the rules for a
1728 non-reference copy initialization. If T1 is reference-related to
1729 T2, cv1 must be the same cv-qualification as, or greater
1730 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1735 }
1737 /* Returns the implicit conversion sequence (see [over.ics]) from type
1738 FROM to type TO. The optional expression EXPR may affect the
1739 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1740 true, this conversion is coming from a C-style cast. */
1745 {
1752 /* Other flags only apply to the primary function in overload
1753 resolution, or after we've chosen one. */
1758 /* FIXME: actually we don't want warnings either, but we can't just
1759 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1760 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1761 We really ought not to issue that warning until we've committed
1762 to that conversion. */
1767 else
1774 {
1778 /* As an extension, allow list-initialization of _Complex. */
1780 {
1784 }
1786 /* Allow conversion from an initializer-list with one element to a
1787 scalar type. */
1789 {
1791 tree elt;
1797 else
1803 {
1806 /* Too many levels of braces, i.e. '{{1}}'. */
1809 }
1810 }
1813 }
1819 {
1831 /* We used to try to bind a reference to a temporary here, but that
1832 is now handled after the recursive call to this function at the end
1833 of reference_binding. */
1835 }
1838 }
1840 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1841 functions. ARGS will not be changed until a single candidate is
1842 selected. */
1851 {
1869 }
1871 /* Return the number of remaining arguments in the parameter list
1872 beginning with ARG. */
1874 static int
1876 {
1881 n++;
1884 }
1886 /* Create an overload candidate for the function or method FN called
1887 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1888 FLAGS is passed on to implicit_conversion.
1890 This does not change ARGS.
1892 CTYPE, if non-NULL, is the type we want to pretend this function
1893 comes from for purposes of overload resolution. */
1900 tsubst_flags_t complain)
1901 {
1905 tree parmnode;
1911 /* At this point we should not see any functions which haven't been
1912 explicitly declared, except for friend functions which will have
1913 been found using argument dependent lookup. */
1916 /* The `this', `in_chrg' and VTT arguments to constructors are not
1917 considered in overload resolution. */
1919 {
1923 {
1926 }
1927 }
1928 else
1934 /* 13.3.2 - Viable functions [over.match.viable]
1935 First, to be a viable function, a candidate function shall have enough
1936 parameters to agree in number with the arguments in the list.
1938 We need to check this first; otherwise, checking the ICSes might cause
1939 us to produce an ill-formed template instantiation. */
1943 {
1947 }
1951 {
1955 }
1956 /* When looking for a function from a subobject from an implicit
1957 copy/move constructor/operator=, don't consider anything that takes (a
1958 reference to) an unrelated type. See c++/44909 and core 1092. */
1960 {
1966 else
1969 {
1972 ctype))
1974 }
1976 /* This only applies at the top level. */
1978 }
1983 /* Second, for F to be a viable function, there shall exist for each
1984 argument an implicit conversion sequence that converts that argument
1985 to the corresponding parameter of F. */
1990 {
1992 tree arg;
2001 else
2010 {
2016 /* The type of the implicit object parameter ('this') for
2017 overload resolution is not always the same as for the
2018 function itself; conversion functions are considered to
2019 be members of the class being converted, and functions
2020 introduced by a using-declaration are considered to be
2021 members of the class that uses them.
2023 Since build_over_call ignores the ICS for the `this'
2024 parameter, we can just change the parm type. */
2026 {
2027 parmtype = cp_build_qualified_type
2030 {
2031 /* If the function has a ref-qualifier, the implicit
2032 object parameter has reference type. */
2035 /* The special handling of 'this' conversions in compare_ics
2036 does not apply if there is a ref-qualifier. */
2038 }
2039 else
2040 {
2044 }
2045 }
2047 /* Core issue 899: When [copy-]initializing a temporary to be bound
2048 to the first parameter of a copy constructor (12.8) called with
2049 a single argument in the context of direct-initialization,
2050 explicit conversion functions are also considered.
2052 So set LOOKUP_COPY_PARM to let reference_binding know that
2053 it's being called in that context. We generalize the above
2054 to handle move constructors and template constructors as well;
2055 the standardese should soon be updated similarly. */
2059 && (same_type_ignoring_top_level_qualifiers_p
2061 {
2064 /* We allow user-defined conversions within init-lists, but
2065 don't list-initialize the copy parm, as that would mean
2066 using two levels of braces for the same type. */
2070 }
2071 else
2077 }
2078 else
2079 {
2083 }
2090 {
2094 }
2097 {
2100 }
2101 }
2103 out:
2106 }
2108 /* Create an overload candidate for the conversion function FN which will
2109 be invoked for expression OBJ, producing a pointer-to-function which
2110 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2111 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2112 passed on to implicit_conversion.
2114 Actually, we don't really care about FN; we care about the type it
2115 converts to. There may be multiple conversion functions that will
2116 convert to that type, and we rely on build_user_type_conversion_1 to
2117 choose the best one; so when we create our candidate, we record the type
2118 instead of the function. */
2124 tsubst_flags_t complain)
2125 {
2143 /* Don't bother looking up the same type twice. */
2148 {
2156 else
2161 {
2165 }
2169 {
2173 }
2174 else
2175 {
2179 }
2186 {
2189 }
2196 }
2200 {
2204 }
2208 }
2210 static void
2214 {
2228 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2229 conversion ops are allowed. We handle that here by just checking for
2230 boolean_type_node because other operators don't ask for it. COND_EXPR
2231 also does contextual conversion to bool for the first operand, but we
2232 handle that in build_conditional_expr, and type1 here is operand 2. */
2237 {
2244 {
2246 /* We need something for printing the candidate. */
2250 }
2252 {
2256 }
2258 }
2260 /* For COND_EXPR we rearranged the arguments; undo that now. */
2262 {
2267 complain);
2270 else
2271 {
2274 boolean_type_node);
2275 }
2276 }
2283 }
2285 static bool
2287 {
2289 }
2291 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2293 static bool
2295 {
2296 /* [over.built]
2298 In this section, the term promoted integral type is used to refer
2299 to those integral types which are preserved by integral promotion
2300 (including e.g. int and long but excluding e.g. char).
2301 Similarly, the term promoted arithmetic type refers to promoted
2302 integral types plus floating types. */
2306 }
2308 /* Create any builtin operator overload candidates for the operator in
2309 question given the converted operand types TYPE1 and TYPE2. The other
2310 args are passed through from add_builtin_candidates to
2311 build_builtin_candidate.
2313 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2314 If CODE is requires candidates operands of the same type of the kind
2315 of which TYPE1 and TYPE2 are, we add both candidates
2316 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2318 static void
2322 tsubst_flags_t complain)
2323 {
2325 {
2333 }
2336 {
2338 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2339 and VQ is either volatile or empty, there exist candidate operator
2340 functions of the form
2341 VQ T& operator++(VQ T&);
2342 T operator++(VQ T&, int);
2343 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2344 type other than bool, and VQ is either volatile or empty, there exist
2345 candidate operator functions of the form
2346 VQ T& operator--(VQ T&);
2347 T operator--(VQ T&, int);
2348 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2349 complete object type, and VQ is either volatile or empty, there exist
2350 candidate operator functions of the form
2351 T*VQ& operator++(T*VQ&);
2352 T*VQ& operator--(T*VQ&);
2353 T* operator++(T*VQ&, int);
2354 T* operator--(T*VQ&, int); */
2363 {
2366 }
2369 /* 7 For every cv-qualified or cv-unqualified object type T, there
2370 exist candidate operator functions of the form
2372 T& operator*(T*);
2374 8 For every function type T, there exist candidate operator functions of
2375 the form
2376 T& operator*(T*); */
2385 /* 9 For every type T, there exist candidate operator functions of the form
2386 T* operator+(T*);
2388 10For every promoted arithmetic type T, there exist candidate operator
2389 functions of the form
2390 T operator+(T);
2391 T operator-(T); */
2401 /* 11For every promoted integral type T, there exist candidate operator
2402 functions of the form
2403 T operator~(T); */
2410 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2411 is the same type as C2 or is a derived class of C2, T is a complete
2412 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2413 there exist candidate operator functions of the form
2414 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2415 where CV12 is the union of CV1 and CV2. */
2419 {
2427 }
2430 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2431 didate operator functions of the form
2432 LR operator*(L, R);
2433 LR operator/(L, R);
2434 LR operator+(L, R);
2435 LR operator-(L, R);
2436 bool operator<(L, R);
2437 bool operator>(L, R);
2438 bool operator<=(L, R);
2439 bool operator>=(L, R);
2440 bool operator==(L, R);
2441 bool operator!=(L, R);
2442 where LR is the result of the usual arithmetic conversions between
2443 types L and R.
2445 14For every pair of types T and I, where T is a cv-qualified or cv-
2446 unqualified complete object type and I is a promoted integral type,
2447 there exist candidate operator functions of the form
2448 T* operator+(T*, I);
2449 T& operator[](T*, I);
2450 T* operator-(T*, I);
2451 T* operator+(I, T*);
2452 T& operator[](I, T*);
2454 15For every T, where T is a pointer to complete object type, there exist
2455 candidate operator functions of the form112)
2456 ptrdiff_t operator-(T, T);
2458 16For every pointer or enumeration type T, there exist candidate operator
2459 functions of the form
2460 bool operator<(T, T);
2461 bool operator>(T, T);
2462 bool operator<=(T, T);
2463 bool operator>=(T, T);
2464 bool operator==(T, T);
2465 bool operator!=(T, T);
2467 17For every pointer to member type T, there exist candidate operator
2468 functions of the form
2469 bool operator==(T, T);
2470 bool operator!=(T, T); */
2477 {
2480 }
2493 {
2496 }
2498 {
2501 }
2502 /* Fall through. */
2518 {
2521 }
2524 {
2527 }
2535 {
2538 }
2540 {
2543 }
2546 /* 18For every pair of promoted integral types L and R, there exist candi-
2547 date operator functions of the form
2548 LR operator%(L, R);
2549 LR operator&(L, R);
2550 LR operator^(L, R);
2551 LR operator|(L, R);
2552 L operator<<(L, R);
2553 L operator>>(L, R);
2554 where LR is the result of the usual arithmetic conversions between
2555 types L and R. */
2563 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2567 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2568 type, VQ is either volatile or empty, and R is a promoted arithmetic
2569 type, there exist candidate operator functions of the form
2570 VQ L& operator=(VQ L&, R);
2571 VQ L& operator*=(VQ L&, R);
2572 VQ L& operator/=(VQ L&, R);
2573 VQ L& operator+=(VQ L&, R);
2574 VQ L& operator-=(VQ L&, R);
2576 20For every pair T, VQ), where T is any type and VQ is either volatile
2577 or empty, there exist candidate operator functions of the form
2578 T*VQ& operator=(T*VQ&, T*);
2580 21For every pair T, VQ), where T is a pointer to member type and VQ is
2581 either volatile or empty, there exist candidate operator functions of
2582 the form
2583 VQ T& operator=(VQ T&, T);
2585 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2586 unqualified complete object type, VQ is either volatile or empty, and
2587 I is a promoted integral type, there exist candidate operator func-
2588 tions of the form
2589 T*VQ& operator+=(T*VQ&, I);
2590 T*VQ& operator-=(T*VQ&, I);
2592 23For every triple L, VQ, R), where L is an integral or enumeration
2593 type, VQ is either volatile or empty, and R is a promoted integral
2594 type, there exist candidate operator functions of the form
2596 VQ L& operator%=(VQ L&, R);
2597 VQ L& operator<<=(VQ L&, R);
2598 VQ L& operator>>=(VQ L&, R);
2599 VQ L& operator&=(VQ L&, R);
2600 VQ L& operator^=(VQ L&, R);
2601 VQ L& operator|=(VQ L&, R); */
2605 {
2609 {
2612 }
2625 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2638 {
2641 }
2646 }
2651 /* [over.built]
2653 For every pair of promoted arithmetic types L and R, there
2654 exist candidate operator functions of the form
2656 LR operator?(bool, L, R);
2658 where LR is the result of the usual arithmetic conversions
2659 between types L and R.
2661 For every type T, where T is a pointer or pointer-to-member
2662 type, there exist candidate operator functions of the form T
2663 operator?(bool, T, T); */
2667 /* That's OK. */
2670 /* Otherwise, the types should be pointers. */
2674 /* We don't check that the two types are the same; the logic
2675 below will actually create two candidates; one in which both
2676 parameter types are TYPE1, and one in which both parameter
2677 types are TYPE2. */
2688 }
2690 /* Make sure we don't create builtin candidates with dependent types. */
2694 {
2695 /* Try to recover if one of the types is non-dependent. But if
2696 there's only one type, there's nothing we can do. */
2699 /* And we lose if both are dependent. */
2702 /* Or if they have different forms. */
2710 }
2712 /* If we're dealing with two pointer types or two enumeral types,
2713 we need candidates for both of them. */
2722 {
2724 {
2726 error_mark_node,
2727 error_mark_node,
2728 CPO_CONVERSION,
2729 tf_none);
2731 {
2732 build_builtin_candidate
2736 }
2737 }
2739 build_builtin_candidate
2741 build_builtin_candidate
2744 }
2746 build_builtin_candidate
2748 }
2750 tree
2752 {
2758 }
2760 /* There are three conditions of builtin candidates:
2762 1) bool-taking candidates. These are the same regardless of the input.
2763 2) pointer-pair taking candidates. These are generated for each type
2764 one of the input types converts to.
2765 3) arithmetic candidates. According to the standard, we should generate
2766 all of these, but I'm trying not to...
2768 Here we generate a superset of the possible candidates for this particular
2769 case. That is a subset of the full set the standard defines, plus some
2770 other cases which the standard disallows. add_builtin_candidate will
2771 filter out the invalid set. */
2773 static void
2777 {
2781 /* TYPES[i] is the set of possible builtin-operator parameter types
2782 we will consider for the Ith argument. */
2787 {
2790 else
2792 }
2795 {
2796 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2797 and VQ is either volatile or empty, there exist candidate operator
2798 functions of the form
2799 VQ T& operator++(VQ T&); */
2809 /* 24There also exist candidate operator functions of the form
2810 bool operator!(bool);
2811 bool operator&&(bool, bool);
2812 bool operator||(bool, bool); */
2815 build_builtin_candidate
2822 build_builtin_candidate
2840 /* Fall through. */
2844 }
2850 {
2852 ;
2854 {
2855 tree convs;
2863 {
2868 }
2874 {
2887 {
2893 }
2897 }
2898 }
2899 else
2900 {
2905 {
2911 }
2913 }
2914 }
2916 /* Run through the possible parameter types of both arguments,
2917 creating candidates with those parameter types. */
2919 {
2921 tree u;
2925 add_builtin_candidate
2928 else
2929 add_builtin_candidate
2932 }
2936 }
2939 /* If TMPL can be successfully instantiated as indicated by
2940 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2942 TMPL is the template. EXPLICIT_TARGS are any explicit template
2943 arguments. ARGLIST is the arguments provided at the call-site.
2944 This does not change ARGLIST. The RETURN_TYPE is the desired type
2945 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2946 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2947 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2955 tsubst_flags_t complain)
2956 {
2966 tree arg;
2968 tree fn;
2972 /* We don't do deduction on the in-charge parameter, the VTT
2973 parameter or 'this'. */
2975 {
2978 else
2980 }
2985 {
2988 else
2990 }
3000 {
3003 }
3007 {
3010 }
3015 args_without_in_chrg,
3016 nargs_without_in_chrg,
3021 {
3022 /* Don't repeat unification later if it already resulted in errors. */
3026 nargs_without_in_chrg,
3028 else
3031 }
3033 /* In [class.copy]:
3035 A member function template is never instantiated to perform the
3036 copy of a class object to an object of its class type.
3038 It's a little unclear what this means; the standard explicitly
3039 does allow a template to be used to copy a class. For example,
3040 in:
3042 struct A {
3043 A(A&);
3044 template <class T> A(const T&);
3045 };
3046 const A f ();
3047 void g () { A a (f ()); }
3049 the member template will be used to make the copy. The section
3050 quoted above appears in the paragraph that forbids constructors
3051 whose only parameter is (a possibly cv-qualified variant of) the
3052 class type, and a logical interpretation is that the intent was
3053 to forbid the instantiation of member templates which would then
3054 have that form. */
3056 {
3059 ctype))
3060 {
3063 }
3064 }
3067 /* Aha, this is a conversion function. */
3070 else
3075 /* This situation can occur if a member template of a template
3076 class is specialized. Then, instantiate_template might return
3077 an instantiation of the specialization, in which case the
3078 DECL_TI_TEMPLATE field will point at the original
3079 specialization. For example:
3081 template <class T> struct S { template <class U> void f(U);
3082 template <> void f(int) {}; };
3083 S<double> sd;
3084 sd.f(3);
3086 Here, TMPL will be template <class U> S<double>::f(U).
3087 And, instantiate template will give us the specialization
3088 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3089 for this will point at template <class T> template <> S<T>::f(int),
3090 so that we can find the definition. For the purposes of
3091 overload resolution, however, we want the original TMPL. */
3093 else
3098 fail:
3101 }
3110 {
3111 return
3116 }
3125 {
3126 return
3130 complain);
3131 }
3133 /* The CANDS are the set of candidates that were considered for
3134 overload resolution. Return the set of viable candidates, or CANDS
3135 if none are viable. If any of the candidates were viable, set
3136 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3137 considered viable only if it is strictly viable. */
3143 {
3149 /* Be strict inside templates, since build_over_call won't actually
3150 do the conversions to get pedwarns. */
3160 {
3164 {
3165 /* Be strict in the presence of a viable candidate. Also if
3166 there are template candidates, so that we get deduction errors
3167 for them instead of silently preferring a bad conversion. */
3170 {
3171 /* Put any spliced near matches back onto the main list so
3172 that we see them if there is no strict match. */
3178 }
3179 }
3182 {
3190 }
3191 else
3193 }
3196 }
3198 static bool
3200 {
3205 }
3207 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3208 words, it is about to become the "this" pointer for a member
3209 function call. Take the address of the object. */
3211 static tree
3213 {
3214 /* In a template, we are only concerned about the type of the
3215 expression, so we can take a shortcut. */
3220 }
3222 /* Returns true iff functions are equivalent. Equivalent functions are
3223 not '==' only if one is a function-local extern function or if
3224 both are extern "C". */
3228 {
3237 }
3239 /* Print information about a candidate being rejected due to INFO. */
3241 static void
3243 {
3248 {
3249 /* Conversion of implicit `this' argument failed. */
3251 /* A bad conversion for 'this' must be discarding cv-quals. */
3254 from);
3255 else
3259 }
3261 {
3266 tf_warning_or_error);
3267 }
3269 /* Conversion of conversion function return value failed. */
3272 else
3275 }
3277 /* Print information about a candidate with WANT parameters and we found
3278 HAVE. */
3280 static void
3282 {
3287 }
3289 /* Print information about one overload candidate CANDIDATE. MSGSTR
3290 is the text to print before the candidate itself.
3292 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3293 to have been run through gettext by the caller. This wart makes
3294 life simpler in print_z_candidates and for the translators. */
3296 static void
3299 {
3306 {
3317 else
3320 }
3327 else
3329 /* Give the user some information about why this candidate failed. */
3331 {
3335 {
3348 "cannot be converted to %qT with a qualification "
3354 "conversion function specialization to %qT is not an "
3359 /* We use template_unification_error_rejection if unification caused
3360 actual non-SFINAE errors, in which case we don't need to repeat
3361 them here. */
3363 {
3367 }
3368 /* Re-run template unification with diagnostics. */
3372 (make_tree_vec
3383 " a constructor taking a single argument of its own "
3388 /* This candidate didn't have any issues or we failed to
3389 handle a particular code. Either way... */
3391 }
3392 }
3393 }
3395 static void
3397 {
3404 /* Remove non-viable deleted candidates. */
3407 {
3412 else
3414 }
3415 /* ...if there are any non-deleted ones. */
3419 /* There may be duplicates in the set of candidates. We put off
3420 checking this condition as long as possible, since we have no way
3421 to eliminate duplicates from a set of functions in less than n^2
3422 time. Now we are about to emit an error message, so it is more
3423 permissible to go slowly. */
3425 {
3427 /* Skip builtin candidates and conversion functions. */
3432 {
3436 else
3438 }
3439 }
3443 }
3445 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3446 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3447 the result of the conversion function to convert it to the final
3448 desired type. Merge the two sequences into a single sequence,
3449 and return the merged sequence. */
3453 {
3459 /* Find the end of the second conversion sequence. */
3461 {
3462 /* The entire sequence is a user-conversion sequence. */
3466 }
3468 /* Replace the identity conversion with the user conversion
3469 sequence. */
3473 }
3475 /* Handle overload resolution for initializing an object of class type from
3476 an initializer list. First we look for a suitable constructor that
3477 takes a std::initializer_list; if we don't find one, we then look for a
3478 non-list constructor.
3480 Parameters are as for add_candidates, except that the arguments are in
3481 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3482 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3484 static void
3491 tsubst_flags_t complain)
3492 {
3497 /* We're looking for a ctor for list-initialization. */
3499 /* And we don't allow narrowing conversions. We also use this flag to
3500 avoid the copy constructor call for copy-list-initialization. */
3503 /* Always use the default constructor if the list is empty (DR 990). */
3506 ;
3507 /* If the class has a list ctor, try passing the list as a single
3508 argument first, but only consider list ctors. */
3510 {
3518 }
3522 /* We aren't looking for list-ctors anymore. */
3524 /* We allow more user-defined conversions within an init-list. */
3530 }
3532 /* Returns the best overload candidate to perform the requested
3533 conversion. This function is used for three the overloading situations
3534 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3535 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3536 per [dcl.init.ref], so we ignore temporary bindings. */
3540 tsubst_flags_t complain)
3541 {
3543 tree fromtype;
3557 /* We represent conversion within a hierarchy using RVALUE_CONV and
3558 BASE_CONV, as specified by [over.best.ics]; these become plain
3559 constructor calls, as specified in [dcl.init]. */
3564 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3565 creating a garbage BASELINK; constructors can't be inherited. */
3569 {
3574 {
3575 /* [class.conv.fct] A conversion function is never used to
3576 convert a (possibly cv-qualified) object to the (possibly
3577 cv-qualified) same object type (or a reference to it), to a
3578 (possibly cv-qualified) base class of that type (or a
3579 reference to it)... */
3580 }
3581 else
3583 }
3590 /* It's OK to bind a temporary for converting constructor arguments, but
3591 not in converting the return value of a conversion operator. */
3597 {
3602 /* We should never try to call the abstract or base constructor
3603 from here. */
3608 {
3609 /* List-initialization. */
3613 }
3614 else
3615 {
3620 }
3623 {
3626 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3627 set, then this is copy-initialization. In that case, "The
3628 result of the call is then used to direct-initialize the
3629 object that is the destination of the copy-initialization."
3630 [dcl.init]
3632 We represent this in the conversion sequence with an
3633 rvalue conversion, which means a constructor call. */
3636 cand->second_conv
3638 }
3639 }
3645 {
3649 /* If we are called to convert to a reference type, we are trying to
3650 find a direct binding, so don't even consider temporaries. If
3651 we don't find a direct binding, the caller will try again to
3652 look for a temporary binding. */
3663 {
3665 conversion *ics
3667 rettype,
3670 complain);
3672 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3673 copy-initialization. In that case, "The result of the
3674 call is then used to direct-initialize the object that is
3675 the destination of the copy-initialization." [dcl.init]
3677 We represent this in the conversion sequence with an
3678 rvalue conversion, which means a constructor call. But
3679 don't add a second rvalue conversion if there's already
3680 one there. Which there really shouldn't be, but it's
3681 harmless since we'd add it here anyway. */
3689 {
3693 }
3696 {
3697 /* 13.3.1.5: For direct-initialization, those explicit
3698 conversion functions that are not hidden within S and
3699 yield type T or a type that can be converted to type T
3700 with a qualification conversion (4.4) are also candidate
3701 functions. */
3702 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3703 I've raised this issue with the committee. --jason 9/2011 */
3706 }
3708 {
3710 cand->reason
3713 }
3716 {
3717 /* 13.3.3.1.2: If the user-defined conversion is specified by
3718 a specialization of a conversion function template, the
3719 second standard conversion sequence shall have exact match
3720 rank. */
3723 }
3724 }
3725 }
3729 {
3733 }
3737 {
3739 {
3743 }
3750 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3751 ambiguous conversion is no worse than another user-defined
3752 conversion. */
3755 }
3757 tree convtype;
3761 /* DR 5: [in the first step of copy-initialization]...if the function
3762 is a constructor, the call initializes a temporary of the
3763 cv-unqualified version of the destination type. */
3765 else
3767 /* Build the user conversion sequence. */
3768 conv = build_conv
3770 convtype,
3776 /* Remember that this was a list-initialization. */
3780 /* Combine it with the second conversion sequence. */
3785 }
3787 /* Wrapper for above. */
3789 tree
3791 tsubst_flags_t complain)
3792 {
3794 tree ret;
3800 {
3803 else
3804 {
3807 }
3808 }
3809 else
3814 }
3816 /* Subroutine of convert_nontype_argument.
3818 EXPR is an argument for a template non-type parameter of integral or
3819 enumeration type. Do any necessary conversions (that are permitted for
3820 non-type arguments) to convert it to the parameter type.
3822 If conversion is successful, returns the converted expression;
3823 otherwise, returns error_mark_node. */
3825 tree
3827 {
3830 tree t;
3838 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3845 /* for a non-type template-parameter of integral or
3846 enumeration type, integral promotions (4.5) and integral
3847 conversions (4.7) are applied. */
3848 /* It should be sufficient to check the outermost conversion step, since
3849 there are no qualification conversions to integer type. */
3852 {
3853 /* A conversion function is OK. If it isn't constexpr, we'll
3854 complain later that the argument isn't constant. */
3856 /* The lvalue-to-rvalue conversion is OK. */
3869 /* and fall through. */
3874 }
3878 else
3881 /* Free all the conversions we allocated. */
3885 }
3887 /* Do any initial processing on the arguments to a function call. */
3891 {
3893 tree arg;
3896 {
3900 {
3904 }
3907 }
3909 }
3911 /* Perform overload resolution on FN, which is called with the ARGS.
3913 Return the candidate function selected by overload resolution, or
3914 NULL if the event that overload resolution failed. In the case
3915 that overload resolution fails, *CANDIDATES will be the set of
3916 candidates considered, and ANY_VIABLE_P will be set to true or
3917 false to indicate whether or not any of the candidates were
3918 viable.
3920 The ARGS should already have gone through RESOLVE_ARGS before this
3921 function is called. */
3928 {
3930 tree explicit_targs;
3941 /* Check FN. */
3948 {
3952 }
3954 /* Add the various candidate functions. */
3959 LOOKUP_NORMAL,
3965 else
3970 }
3972 /* Print an error message about being unable to build a call to FN with
3973 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
3974 be located; CANDIDATES is a possibly empty list of such
3975 functions. */
3977 static void
3980 {
3987 else
3992 }
3994 /* Return an expression for a call to FN (a namespace-scope function,
3995 or a static member function) with the ARGS. This may change
3996 ARGS. */
3998 tree
4000 tsubst_flags_t complain)
4001 {
4005 tree result;
4008 {
4012 }
4017 /* If this function was found without using argument dependent
4018 lookup, then we want to ignore any undeclared friend
4019 functions. */
4021 {
4026 {
4030 }
4031 }
4033 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4037 complain);
4040 {
4042 {
4049 }
4051 }
4052 else
4053 {
4055 /* If fn is template_id_expr, the call has explicit template arguments
4056 (e.g. func<int>(5)), communicate this info to build_over_call
4057 through flags so that later we can use it to decide whether to warn
4058 about peculiar null pointer conversion. */
4062 }
4064 /* Free all the conversions we allocated. */
4068 }
4070 /* Build a call to a global operator new. FNNAME is the name of the
4071 operator (either "operator new" or "operator new[]") and ARGS are
4072 the arguments provided. This may change ARGS. *SIZE points to the
4073 total number of bytes required by the allocation, and is updated if
4074 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4075 be used. If this function determines that no cookie should be
4076 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4077 is not NULL_TREE, it is evaluated before calculating the final
4078 array size, and if it fails, the array size is replaced with
4079 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4080 is non-NULL, it will be set, upon return, to the allocation
4081 function called. */
4083 tree
4087 {
4089 tree fns;
4096 /* Set to (size_t)-1 if the size check fails. */
4098 {
4104 }
4110 /* Based on:
4112 [expr.new]
4114 If this lookup fails to find the name, or if the allocated type
4115 is not a class type, the allocation function's name is looked
4116 up in the global scope.
4118 we disregard block-scope declarations of "operator new". */
4121 /* Figure out what function is being called. */
4123 complain);
4125 /* If no suitable function could be found, issue an error message
4126 and give up. */
4128 {
4132 }
4134 /* If a cookie is required, add some extra space. Whether
4135 or not a cookie is required cannot be determined until
4136 after we know which function was called. */
4138 {
4140 tree arg_types;
4143 /* Skip the size_t parameter. */
4145 /* Check the remaining parameters (if any). */
4149 ptr_type_node))
4151 /* If we need a cookie, adjust the number of bytes allocated. */
4153 {
4154 /* Update the total size. */
4156 /* Set to (size_t)-1 if the size check fails. */
4160 /* Update the argument list to reflect the adjusted size. */
4162 }
4163 else
4165 }
4167 /* Tell our caller which function we decided to call. */
4171 /* Build the CALL_EXPR. */
4173 }
4175 /* Build a new call to operator(). This may change ARGS. */
4177 static tree
4179 {
4193 {
4195 /* It's no good looking for an overloaded operator() on a
4196 pointer-to-member-function. */
4197 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4199 }
4202 {
4206 }
4207 else
4211 {
4215 }
4217 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4221 {
4229 }
4234 {
4243 {
4250 add_template_conv_candidate
4254 else
4258 }
4259 }
4261 /* Be strict here because if we choose a bad conversion candidate, the
4262 errors we get won't mention the call context. */
4265 {
4267 {
4271 }
4273 }
4274 else
4275 {
4278 {
4280 {
4284 }
4286 }
4287 /* Since cand->fn will be a type, not a function, for a conversion
4288 function, we must be careful not to unconditionally look at
4289 DECL_NAME here. */
4293 else
4294 {
4296 complain);
4299 }
4300 }
4302 /* Free all the conversions we allocated. */
4306 }
4308 /* Wrapper for above. */
4310 tree
4312 {
4313 tree ret;
4318 }
4320 /* Called by op_error to prepare format strings suitable for the error
4321 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4322 and a suffix (controlled by NTYPES). */
4326 {
4336 else
4340 }
4342 static void
4345 {
4350 else
4354 {
4360 else
4372 else
4382 else
4393 else
4403 else
4408 else
4412 else
4417 }
4418 }
4420 /* Return the implicit conversion sequence that could be used to
4421 convert E1 to E2 in [expr.cond]. */
4425 {
4431 /* [expr.cond]
4433 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4434 implicitly converted (clause _conv_) to the type "lvalue reference to
4435 T2", subject to the constraint that in the conversion the
4436 reference must bind directly (_dcl.init.ref_) to an lvalue.
4438 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4439 implicitly converted to the type "rvalue reference to T2", subject to
4440 the constraint that the reference must bind directly. */
4442 {
4445 t1,
4446 e1,
4448 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4450 complain);
4453 }
4455 /* If E2 is a prvalue or if neither of the conversions above can be done
4456 and at least one of the operands has (possibly cv-qualified) class
4457 type: */
4461 /* [expr.cond]
4463 If E1 and E2 have class type, and the underlying class types are
4464 the same or one is a base class of the other: E1 can be converted
4465 to match E2 if the class of T2 is the same type as, or a base
4466 class of, the class of T1, and the cv-qualification of T2 is the
4467 same cv-qualification as, or a greater cv-qualification than, the
4468 cv-qualification of T1. If the conversion is applied, E1 is
4469 changed to an rvalue of type T2 that still refers to the original
4470 source class object (or the appropriate subobject thereof). */
4473 {
4475 {
4480 else
4483 }
4484 else
4486 }
4487 else
4488 /* [expr.cond]
4490 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4491 converted to the type that expression E2 would have if E2 were
4492 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4495 }
4497 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4498 arguments to the conditional expression. */
4500 static tree
4502 tsubst_flags_t complain)
4503 {
4504 tree arg2_type;
4505 tree arg3_type;
4514 /* As a G++ extension, the second argument to the conditional can be
4515 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4516 c'.) If the second operand is omitted, make sure it is
4517 calculated only once. */
4519 {
4524 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4527 else
4529 }
4531 /* If something has already gone wrong, just pass that fact up the
4532 tree. */
4542 {
4547 /* force_rvalue can return error_mark on valid arguments. */
4559 {
4560 /* Rely on the error messages of the scalar version. */
4569 {
4577 }
4581 /* We could pass complain & tf_warning to unsafe_conversion_p,
4582 but the warnings (like Wsign-conversion) have already been
4583 given by the scalar build_conditional_expr_1. We still check
4584 unsafe_conversion_p to forbid truncating long long -> float. */
4586 {
4591 }
4593 {
4598 }
4608 }
4612 {
4618 {
4622 {
4628 }
4630 {
4636 }
4639 }
4640 }
4646 {
4649 "incompatible vector types in conditional expression: "
4653 }
4659 }
4661 /* [expr.cond]
4663 The first expression is implicitly converted to bool (clause
4664 _conv_). */
4666 LOOKUP_NORMAL);
4670 /* [expr.cond]
4672 If either the second or the third operand has type (possibly
4673 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4674 array-to-pointer (_conv.array_), and function-to-pointer
4675 (_conv.func_) standard conversions are performed on the second
4676 and third operands. */
4680 {
4681 /* Do the conversions. We don't these for `void' type arguments
4682 since it can't have any effect and since decay_conversion
4683 does not handle that case gracefully. */
4691 /* [expr.cond]
4693 One of the following shall hold:
4695 --The second or the third operand (but not both) is a
4696 throw-expression (_except.throw_); the result is of the
4697 type of the other and is an rvalue.
4699 --Both the second and the third operands have type void; the
4700 result is of type void and is an rvalue.
4702 We must avoid calling force_rvalue for expressions of type
4703 "void" because it will complain that their value is being
4704 used. */
4707 {
4709 {
4713 }
4716 }
4719 {
4721 {
4725 }
4728 }
4731 else
4732 {
4734 {
4737 "second operand to the conditional operator "
4738 "is of type %<void%>, but the third operand is "
4740 else
4742 "third operand to the conditional operator "
4743 "is of type %<void%>, but the second operand is "
4745 }
4747 }
4751 }
4752 /* [expr.cond]
4754 Otherwise, if the second and third operand have different types,
4755 and either has (possibly cv-qualified) class type, or if both are
4756 glvalues of the same value category and the same type except for
4757 cv-qualification, an attempt is made to convert each of those operands
4758 to the type of the other. */
4762 arg3_type)
4766 {
4771 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4777 /* [expr.cond]
4779 If both can be converted, or one can be converted but the
4780 conversion is ambiguous, the program is ill-formed. If
4781 neither can be converted, the operands are left unchanged and
4782 further checking is performed as described below. If exactly
4783 one conversion is possible, that conversion is applied to the
4784 chosen operand and the converted operand is used in place of
4785 the original operand for the remainder of this section. */
4790 {
4792 {
4799 else
4801 }
4803 }
4805 {
4809 /* Even if CONV2 is a valid conversion, the result of the
4810 conversion may be invalid. For example, if ARG3 has type
4811 "volatile X", and X does not have a copy constructor
4812 accepting a "volatile X&", then even if ARG2 can be
4813 converted to X, the conversion will fail. */
4817 }
4819 {
4826 }
4828 /* Free all the conversions we allocated. */
4834 /* If, after the conversion, both operands have class type,
4835 treat the cv-qualification of both operands as if it were the
4836 union of the cv-qualification of the operands.
4838 The standard is not clear about what to do in this
4839 circumstance. For example, if the first operand has type
4840 "const X" and the second operand has a user-defined
4841 conversion to "volatile X", what is the type of the second
4842 operand after this step? Making it be "const X" (matching
4843 the first operand) seems wrong, as that discards the
4844 qualification without actually performing a copy. Leaving it
4845 as "volatile X" seems wrong as that will result in the
4846 conditional expression failing altogether, even though,
4847 according to this step, the one operand could be converted to
4848 the type of the other. */
4856 }
4858 /* [expr.cond]
4860 If the second and third operands are glvalues of the same value
4861 category and have the same type, the result is of that type and
4862 value category. */
4866 {
4871 }
4873 /* [expr.cond]
4875 Otherwise, the result is an rvalue. If the second and third
4876 operand do not have the same type, and either has (possibly
4877 cv-qualified) class type, overload resolution is used to
4878 determine the conversions (if any) to be applied to the operands
4879 (_over.match.oper_, _over.built_). */
4883 {
4888 /* Rearrange the arguments so that add_builtin_candidate only has
4889 to know about two args. In build_builtin_candidate, the
4890 arguments are unscrambled. */
4895 COND_EXPR,
4896 NOP_EXPR,
4898 args,
4901 /* [expr.cond]
4903 If the overload resolution fails, the program is
4904 ill-formed. */
4907 {
4912 }
4915 {
4917 {
4920 }
4922 }
4924 /* [expr.cond]
4926 Otherwise, the conversions thus determined are applied, and
4927 the converted operands are used in place of the original
4928 operands for the remainder of this section. */
4937 }
4939 /* [expr.cond]
4941 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4942 and function-to-pointer (_conv.func_) standard conversions are
4943 performed on the second and third operands.
4945 We need to force the lvalue-to-rvalue conversion here for class types,
4946 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4947 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4948 regions. */
4961 /* [expr.cond]
4963 After those conversions, one of the following shall hold:
4965 --The second and third operands have the same type; the result is of
4966 that type. */
4969 /* [expr.cond]
4971 --The second and third operands have arithmetic or enumeration
4972 type; the usual arithmetic conversions are performed to bring
4973 them to a common type, and the result is of that type. */
4978 {
4979 /* In this case, there is always a common type. */
4981 arg3_type);
4984 "implicit conversion from %qT to %qT to "
4986 loc);
4990 {
4994 /* Two enumerators from the same enumeration can have different
5000 }
5007 {
5011 }
5015 }
5016 /* [expr.cond]
5018 --The second and third operands have pointer type, or one has
5019 pointer type and the other is a null pointer constant; pointer
5020 conversions (_conv.ptr_) and qualification conversions
5021 (_conv.qual_) are performed to bring them to their composite
5022 pointer type (_expr.rel_). The result is of the composite
5023 pointer type.
5025 --The second and third operands have pointer to member type, or
5026 one has pointer to member type and the other is a null pointer
5027 constant; pointer to member conversions (_conv.mem_) and
5028 qualification conversions (_conv.qual_) are performed to bring
5029 them to a common type, whose cv-qualification shall match the
5030 cv-qualification of either the second or the third operand.
5031 The result is of the common type. */
5039 {
5042 complain);
5047 }
5050 {
5055 }
5060 valid_operands:
5063 /* Avoid folding within decltype (c++/42013) and noexcept. */
5066 /* We can't use result_type below, as fold might have returned a
5067 throw_expr. */
5070 {
5071 /* Expand both sides into the same slot, hopefully the target of
5072 the ?: expression. We used to check for TARGET_EXPRs here,
5073 but now we sometimes wrap them in NOP_EXPRs so the test would
5074 fail. */
5077 /* If this expression is an rvalue, but might be mistaken for an
5078 lvalue, we must add a NON_LVALUE_EXPR. */
5080 }
5081 else
5085 }
5087 /* Wrapper for above. */
5089 tree
5091 tsubst_flags_t complain)
5092 {
5093 tree ret;
5098 }
5100 /* OPERAND is an operand to an expression. Perform necessary steps
5101 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5102 returned. */
5104 static tree
5106 {
5108 {
5111 /* Make sure the template type is instantiated now. */
5113 }
5116 }
5118 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5119 OVERLOAD) to the CANDIDATES, returning an updated list of
5120 CANDIDATES. The ARGS are the arguments provided to the call;
5121 if FIRST_ARG is non-null it is the implicit object argument,
5122 otherwise the first element of ARGS is used if needed. The
5123 EXPLICIT_TARGS are explicit template arguments provided.
5124 TEMPLATE_ONLY is true if only template functions should be
5125 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5126 add_function_candidate. */
5128 static void
5130 tree return_type,
5135 tsubst_flags_t complain)
5136 {
5137 tree ctype;
5141 unification_kind_t strict;
5142 tree fn;
5147 /* Precalculate special handling of constructors and conversion ops. */
5150 {
5154 /* We're doing return_type(x). */
5156 else
5157 /* We're doing x.operator return_type(). */
5159 /* [over.match.funcs] For conversion functions, the function
5160 is considered to be a member of the class of the implicit
5161 object argument for the purpose of defining the type of
5162 the implicit object parameter. */
5164 }
5165 else
5166 {
5168 {
5170 /* For list-initialization we consider explicit constructors
5171 and complain if one is chosen. */
5172 check_converting
5175 }
5176 else
5177 {
5180 }
5183 }
5187 else
5188 /* Delay creating the implicit this parameter until it is needed. */
5192 {
5193 tree fn_first_arg;
5203 /* Figure out which set of arguments to use. */
5205 {
5206 /* If this function is a non-static member and we didn't get an
5207 implicit object argument, move it out of args. */
5209 {
5211 tree arg;
5218 }
5222 }
5223 else
5224 {
5225 /* Otherwise, just use the list of arguments provided. */
5228 }
5232 fn,
5233 ctype,
5234 explicit_targs,
5235 fn_first_arg,
5236 fn_args,
5237 return_type,
5238 access_path,
5239 conversion_path,
5240 flags,
5241 strict,
5242 complain);
5245 fn,
5246 ctype,
5247 fn_first_arg,
5248 fn_args,
5249 access_path,
5250 conversion_path,
5251 flags,
5252 complain);
5253 }
5254 }
5256 static tree
5259 {
5262 tree fnname;
5280 {
5284 }
5285 else
5292 {
5297 /* Use build_op_new_call and build_op_delete_call instead. */
5301 /* Use build_op_call instead. */
5308 /* These are saved for the sake of warn_logical_operator. */
5318 /* These are saved for the sake of maybe_warn_bool_compare. */
5323 /* =, ->, [], () must be non-static member functions. */
5334 }
5340 /* Use build_conditional_expr instead. */
5356 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5359 /* Add namespace-scope operators to the list of functions to
5360 consider. */
5372 /* Add class-member operators to the candidate set. */
5374 {
5375 tree fns;
5379 {
5382 }
5390 }
5391 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5392 only non-member functions that have type T1 or reference to
5393 cv-qualified-opt T1 for the first argument, if the first argument
5394 has an enumeration type, or T2 or reference to cv-qualified-opt
5395 T2 for the second argument, if the the second argument has an
5396 enumeration type. Filter out those that don't match. */
5398 {
5402 {
5412 {
5418 && (same_type_ignoring_top_level_qualifiers_p
5423 }
5425 /* No argument has an appropriate type, so remove this
5426 candidate function from the list. */
5428 {
5431 }
5432 }
5433 }
5439 {
5442 /* For these, the built-in candidates set is empty
5443 [over.match.oper]/3. We don't want non-strict matches
5444 because exact matches are always possible with built-in
5445 operators. The built-in candidate set for COMPONENT_REF
5446 would be empty too, but since there are no such built-in
5447 operators, we accept non-strict matches for them. */
5454 }
5458 {
5460 {
5463 /* Don't try anything fancy if we're not allowed to produce
5464 errors. */
5468 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5469 distinguish between prefix and postfix ++ and
5470 operator++() was used for both, so we allow this with
5471 -fpermissive. */
5472 else
5473 {
5479 }
5486 else
5492 /* The caller will deal with these. */
5502 {
5503 /* If one of the arguments of the operator represents
5504 an invalid use of member function pointer, try to report
5505 a meaningful error ... */
5510 else
5511 {
5512 /* ... Otherwise, report the more generic
5513 "no matching operator found" error */
5516 }
5517 }
5520 }
5521 }
5522 else
5523 {
5526 {
5528 {
5531 }
5533 }
5535 {
5541 else
5543 }
5544 else
5545 {
5546 /* Give any warnings we noticed during overload resolution. */
5548 {
5552 }
5554 /* Check for comparison of different enum types. */
5556 {
5568 {
5572 }
5576 }
5578 /* We need to strip any leading REF_BIND so that bitfields
5579 don't cause errors. This should not remove any important
5580 conversions, because builtins don't apply to class
5581 objects directly. */
5588 {
5592 else
5595 /* We need to call warn_logical_operator before
5596 converting arg2 to a boolean_type, but after
5597 decaying an enumerator to its value. */
5604 }
5606 {
5611 }
5613 }
5614 }
5616 user_defined_result_ready:
5618 /* Free all the conversions we allocated. */
5624 builtin:
5626 {
5639 /* Fall through. */
5649 /* Fall through. */
5682 complain),
5685 /* The caller will deal with these. */
5693 }
5695 }
5697 /* Wrapper for above. */
5699 tree
5703 {
5704 tree ret;
5710 }
5712 /* Returns true if FN has two parameters, of which the second has type
5713 size_t. */
5715 static bool
5717 {
5722 }
5724 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5725 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5727 bool
5729 {
5730 /* A template instance is never a usual deallocation function,
5731 regardless of its signature. */
5736 /* If a class T has a member deallocation function named operator delete
5737 with exactly one parameter, then that function is a usual
5738 (non-placement) deallocation function. If class T does not declare
5739 such an operator delete but does declare a member deallocation
5740 function named operator delete with exactly two parameters, the second
5741 of which has type std::size_t (18.2), then this function is a usual
5742 deallocation function. */
5749 }
5751 /* Build a call to operator delete. This has to be handled very specially,
5752 because the restrictions on what signatures match are different from all
5753 other call instances. For a normal delete, only a delete taking (void *)
5754 or (void *, size_t) is accepted. For a placement delete, only an exact
5755 match with the placement new is accepted.
5757 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5758 ADDR is the pointer to be deleted.
5759 SIZE is the size of the memory block to be deleted.
5760 GLOBAL_P is true if the delete-expression should not consider
5761 class-specific delete operators.
5762 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5764 If this call to "operator delete" is being generated as part to
5765 deallocate memory allocated via a new-expression (as per [expr.new]
5766 which requires that if the initialization throws an exception then
5767 we call a deallocation function), then ALLOC_FN is the allocation
5768 function. */
5770 tree
5774 {
5788 /* In [class.free]
5790 If the result of the lookup is ambiguous or inaccessible, or if
5791 the lookup selects a placement deallocation function, the
5792 program is ill-formed.
5794 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5795 {
5799 }
5800 else
5806 /* Strip const and volatile from addr. */
5810 {
5811 /* "A declaration of a placement deallocation function matches the
5812 declaration of a placement allocation function if it has the same
5813 number of parameters and, after parameter transformations (8.3.5),
5814 all parameter types except the first are identical."
5816 So we build up the function type we want and ask instantiate_type
5817 to get it for us. */
5829 /* "If the lookup finds the two-parameter form of a usual deallocation
5830 function (3.7.4.2) and that function, considered as a placement
5831 deallocation function, would have been selected as a match for the
5832 allocation function, the program is ill-formed." */
5834 {
5842 /* But if the class has an operator delete (void *), then that is
5843 the usual deallocation function, so we shouldn't complain
5844 about using the operator delete (void *, size_t). */
5848 {
5853 }
5854 /* Before C++14 a two-parameter global deallocation function is
5855 always a placement deallocation function, but warn if
5856 -Wc++14-compat. */
5858 {
5863 }
5866 {
5868 {
5869 /* Only mention C++14 for namespace-scope delete. */
5872 else
5875 }
5876 }
5877 else
5879 ok:;
5880 }
5881 }
5882 else
5883 /* "Any non-placement deallocation function matches a non-placement
5884 allocation function. If the lookup finds a single matching
5885 deallocation function, that function will be called; otherwise, no
5886 deallocation function will be called." */
5889 {
5892 {
5894 /* "If a class T has a member deallocation function named
5895 operator delete with exactly one parameter, then that
5896 function is a usual (non-placement) deallocation
5897 function. If class T does not declare such an operator
5898 delete but does declare a member deallocation function named
5899 operator delete with exactly two parameters, the second of
5900 which has type std::size_t (18.2), then this function is a
5901 usual deallocation function."
5903 So in a class (void*) beats (void*, size_t). */
5905 {
5908 }
5909 /* At global scope (in C++14 and above) the rules are different:
5911 If deallocation function lookup finds both a usual
5912 deallocation function with only a pointer parameter and a
5913 usual deallocation function with both a pointer parameter
5914 and a size parameter, the function to be called is selected
5915 as follows:
5917 * If the type is complete and if, for the second alternative
5918 (delete array) only, the operand is a pointer to a class
5919 type with a non-trivial destructor or a (possibly
5920 multi-dimensional) array thereof, the function with two
5921 parameters is selected.
5923 * Otherwise, it is unspecified which of the two deallocation
5924 functions is selected. */
5925 else
5926 {
5930 /* We need a cookie to determine the array size. */
5935 }
5936 }
5937 }
5939 /* If we have a matching function, call it. */
5941 {
5944 /* If the FN is a member function, make sure that it is
5945 accessible. */
5948 complain);
5950 /* Core issue 901: It's ok to new a type with deleted delete. */
5955 {
5956 /* The placement args might not be suitable for overload
5957 resolution at this point, so build the call directly. */
5967 }
5968 else
5969 {
5970 tree ret;
5978 }
5979 }
5981 /* [expr.new]
5983 If no unambiguous matching deallocation function can be found,
5984 propagating the exception does not cause the object's memory to
5985 be freed. */
5987 {
5991 alloc_fn);
5993 }
5999 }
6001 /* If the current scope isn't allowed to access DECL along
6002 BASETYPE_PATH, give an error. The most derived class in
6003 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6004 the declaration to use in the error diagnostic. */
6006 bool
6008 tsubst_flags_t complain)
6009 {
6013 {
6015 {
6017 {
6021 }
6023 {
6027 }
6028 else
6029 {
6032 }
6033 }
6035 }
6038 }
6040 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6041 bitwise or of LOOKUP_* values. If any errors are warnings are
6042 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6043 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6044 to NULL. */
6046 static tree
6049 {
6062 else
6065 }
6067 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6068 EXPR is implicitly converted to type TOTYPE.
6069 FN and ARGNUM are used for diagnostics. */
6071 static void
6073 {
6074 /* Issue warnings about peculiar, but valid, uses of NULL. */
6077 {
6078 source_location loc =
6085 else
6088 }
6090 /* Issue warnings if "false" is converted to a NULL pointer */
6093 {
6096 "converting %<false%> to pointer type for argument %P "
6098 else
6101 }
6102 }
6104 /* We gave a diagnostic during a conversion. If this was in the second
6105 standard conversion sequence of a user-defined conversion sequence, say
6106 which user-defined conversion. */
6108 static void
6110 {
6114 {
6118 }
6119 }
6121 /* Perform the conversions in CONVS on the expression EXPR. FN and
6122 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6123 indicates the `this' argument of a method. INNER is nonzero when
6124 being called to continue a conversion chain. It is negative when a
6125 reference binding will be applied, positive otherwise. If
6126 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6127 conversions will be emitted if appropriate. If C_CAST_P is true,
6128 this conversion is coming from a C-style cast; in that case,
6129 conversions to inaccessible bases are permitted. */
6131 static tree
6135 {
6137 diagnostic_t diag_kind;
6153 {
6157 /* Give a helpful error if this is bad because of excess braces. */
6162 {
6168 }
6170 /* Give a helpful error if this is bad because a conversion to bool
6171 from std::nullptr_t requires direct-initialization. */
6179 {
6181 {
6184 totype);
6190 complain);
6194 complain);
6195 else
6201 }
6203 {
6207 complain);
6209 }
6214 complain);
6217 }
6226 }
6232 {
6234 {
6239 /* If we're initializing from {}, it's value-initialization. Note
6240 that under the resolution of core 1630, value-initialization can
6241 use explicit constructors. */
6245 {
6250 {
6253 }
6255 }
6257 /* When converting from an init list we consider explicit
6258 constructors, but actually trying to call one is an error. */
6260 /* Unless this is for direct-list-initialization. */
6262 {
6267 }
6271 /* Set user_conv_p on the argument conversions, so rvalue/base
6272 handling knows not to allow any more UDCs. */
6278 /* If this is a constructor or a function returning an aggr type,
6279 we need to build up a TARGET_EXPR. */
6281 {
6284 /* Remember that this was list-initialization. */
6287 }
6290 }
6293 {
6299 else
6301 }
6306 /* Convert a constant to its underlying value, unless we are
6307 about to bind it to a reference, in which case we need to
6308 leave it as an lvalue. */
6310 {
6313 /* If __null has been converted to an integer type, we do not
6314 want to warn about uses of EXPR as an integer, rather than
6315 as a pointer. */
6317 }
6320 /* We leave bad_p off ck_ambig because overload resolution considers
6321 it valid, it just fails when we try to perform it. So we need to
6322 check complain here, too. */
6324 {
6325 /* Call build_user_type_conversion again for the error. */
6327 complain);
6331 }
6335 {
6336 /* Conversion to std::initializer_list<T>. */
6344 /* Convert all the elements. */
6346 {
6357 }
6358 /* Build up the array. */
6359 elttype = cp_build_qualified_type
6363 /* Take the address explicitly rather than via decay_conversion
6364 to avoid the error about taking the address of a temporary. */
6370 /* Build up the initializer_list object. */
6378 }
6382 {
6391 }
6394 complain);
6401 };
6406 c_cast_p,
6407 complain);
6412 {
6420 /* Else fall through. */
6423 {
6424 /* We are going to bind a reference directly to a base-class
6425 subobject of EXPR. */
6426 /* Build an expression for `*((base*) &expr)'. */
6430 }
6432 /* Copy-initialization where the cv-unqualified version of the source
6433 type is the same class as, or a derived class of, the class of the
6434 destination [is treated as direct-initialization]. [dcl.init] */
6437 /* This conversion is being done in the context of a user-defined
6438 conversion (i.e. the second step of copy-initialization), so
6439 don't allow any more. */
6445 /* Copy-list-initialization doesn't actually involve a copy. */
6449 {
6454 }
6459 {
6463 {
6476 else
6483 }
6485 /* If necessary, create a temporary.
6487 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6488 that need temporaries, even when their types are reference
6489 compatible with the type of reference being bound, so the
6490 upcoming call to cp_build_addr_expr doesn't fail. */
6494 {
6495 /* Otherwise, a temporary of type "cv1 T1" is created and
6496 initialized from the initializer expression using the rules
6497 for a non-reference copy-initialization (8.5). */
6506 {
6507 /* If the reference is volatile or non-const, we
6508 cannot create a temporary. */
6515 else
6519 }
6520 /* If the source is a packed field, and we must use a copy
6521 constructor, then building the target expr will require
6522 binding the field to the reference parameter to the
6523 copy constructor, and we'll end up with an infinite
6524 loop. If we can use a bitwise copy, then we'll be
6525 OK. */
6529 {
6533 }
6535 {
6538 }
6540 }
6542 /* Take the address of the thing to which we will bind the
6543 reference. */
6548 /* Convert it to a pointer to the type referred to by the
6549 reference. This will adjust the pointer if a derived to
6550 base conversion is being performed. */
6553 /* Convert the pointer to the desired reference type. */
6555 }
6561 /* Warn about deprecated conversion if appropriate. */
6577 }
6585 else
6589 }
6591 /* ARG is being passed to a varargs function. Perform any conversions
6592 required. Return the converted value. */
6594 tree
6596 {
6597 tree arg_type;
6600 /* [expr.call]
6602 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6603 standard conversions are performed. */
6606 /* [expr.call]
6608 If the argument has integral or enumeration type that is subject
6609 to the integral promotions (_conv.prom_), or a floating point
6610 type that is subject to the floating point promotion
6611 (_conv.fpprom_), the value of the argument is converted to the
6612 promoted type before the call. */
6617 {
6621 "implicit conversion from %qT to %qT when passing "
6625 }
6629 {
6631 {
6633 complain);
6643 }
6644 else
6646 }
6652 /* In a template (or ill-formed code), we can have an incomplete type
6653 even after require_complete_type_sfinae, in which case we don't know
6654 whether it has trivial copy or not. */
6656 {
6657 /* Build up a real lvalue-to-rvalue conversion in case the
6658 copy constructor is trivial but not callable. */
6662 /* [expr.call] 5.2.2/7:
6663 Passing a potentially-evaluated argument of class type (Clause 9)
6664 with a non-trivial copy constructor or a non-trivial destructor
6665 with no corresponding parameter is conditionally-supported, with
6666 implementation-defined semantics.
6668 We support it as pass-by-invisible-reference, just like a normal
6669 value parameter.
6671 If the call appears in the context of a sizeof expression,
6672 it is not potentially-evaluated. */
6676 {
6679 "passing objects of non-trivially-copyable "
6681 arg_type);
6683 }
6684 }
6687 }
6689 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6691 tree
6693 {
6695 {
6699 }
6709 {
6712 }
6716 {
6717 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6718 it as pass by invisible reference. */
6720 "receiving objects of non-trivially-copyable type %q#T "
6726 }
6729 }
6731 /* TYPE has been given to va_arg. Apply the default conversions which
6732 would have happened when passed via ellipsis. Return the promoted
6733 type, or the passed type if there is no change. */
6735 tree
6737 {
6738 tree promote;
6740 /* Perform the array-to-pointer and function-to-pointer
6741 conversions. */
6749 }
6751 /* ARG is a default argument expression being passed to a parameter of
6752 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6753 zero-based argument number. Do any required conversions. Return
6754 the converted value. */
6757 void
6761 void
6765 tree
6767 tsubst_flags_t complain)
6768 {
6770 tree t;
6772 /* See through clones. */
6775 /* Detect recursion. */
6778 {
6782 }
6784 /* If the ARG is an unparsed default argument expression, the
6785 conversion cannot be performed. */
6787 {
6792 }
6799 /* Due to:
6801 [dcl.fct.default]
6803 The names in the expression are bound, and the semantic
6804 constraints are checked, at the point where the default
6805 expressions appears.
6807 we must not perform access checks here. */
6809 /* We must make a copy of ARG, in case subsequent processing
6810 alters any part of it. */
6814 complain);
6821 }
6823 /* Returns the type which will really be used for passing an argument of
6824 type TYPE. */
6826 tree
6828 {
6829 /* Pass classes with copy ctors by invisible reference. */
6831 {
6833 /* There are no other pointers to this temporary. */
6835 }
6843 }
6845 /* Actually perform the appropriate conversion. */
6847 tree
6849 {
6850 tree bitfield_type;
6852 /* If VAL is a bitfield, then -- since it has already been converted
6853 to TYPE -- it cannot have a precision greater than TYPE.
6855 If it has a smaller precision, we must widen it here. For
6856 example, passing "int f:3;" to a function expecting an "int" will
6857 not result in any conversion before this point.
6859 If the precision is the same we must not risk widening. For
6860 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6861 often have type "int", even though the C++ type for the field is
6862 "long long". If the value is being passed to a function
6863 expecting an "int", then no conversions will be required. But,
6864 if we call convert_bitfield_to_declared_type, the bitfield will
6865 be converted to "long long". */
6872 ;
6873 /* Pass classes with copy ctors by invisible reference. */
6883 {
6892 }
6894 }
6896 /* Returns true iff FN is a function with magic varargs, i.e. ones for
6897 which no conversions at all should be done. This is true for some
6898 builtins which don't act like normal functions. */
6900 bool
6902 {
6908 {
6918 }
6921 }
6923 /* Returns the decl of the dispatcher function if FN is a function version. */
6925 tree
6927 {
6937 {
6941 }
6946 }
6948 /* fn is a function version dispatcher that is marked used. Mark all the
6949 semantically identical function versions it will dispatch as used. */
6951 void
6953 {
6970 /* All semantically identical versions are chained. Traverse and mark each
6971 one of them as used. */
6974 {
6977 }
6978 }
6980 /* Build a call to "the copy constructor" for the type of A, even if it
6981 wouldn't be selected by normal overload resolution. Used for
6982 diagnostics. */
6984 static tree
6986 {
6997 }
6999 /* Subroutine of the various build_*_call functions. Overload resolution
7000 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7001 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7002 bitmask of various LOOKUP_* flags which apply to the call itself. */
7004 static tree
7006 {
7014 tree val;
7023 /* In a template, there is no need to perform all of the work that
7024 is normally done. We are only interested in the type of the call
7025 expression, i.e., the return type of the function. Any semantic
7026 errors will be deferred until the template is instantiated. */
7028 {
7030 tree return_type;
7038 else
7039 {
7042 tree arg;
7050 }
7060 }
7062 /* Give any warnings we noticed during overload resolution. */
7064 {
7068 }
7070 /* Make =delete work with SFINAE. */
7075 {
7076 tree access_fn;
7077 /* If FN is a template function, two cases must be considered.
7078 For example:
7080 struct A {
7081 protected:
7082 template <class T> void f();
7083 };
7084 template <class T> struct B {
7085 protected:
7086 void g();
7087 };
7088 struct C : A, B<int> {
7089 using A::f; // #1
7090 using B<int>::g; // #2
7091 };
7093 In case #1 where `A::f' is a member template, DECL_ACCESS is
7094 recorded in the primary template but not in its specialization.
7095 We check access of FN using its primary template.
7097 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7098 because it is a member of class template B, DECL_ACCESS is
7099 recorded in the specialization `B<int>::g'. We cannot use its
7100 primary template because `B<T>::g' and `B<int>::g' may have
7101 different access. */
7105 else
7110 }
7112 /* If we're checking for implicit delete, don't bother with argument
7113 conversions. */
7115 {
7117 {
7121 }
7125 /* Reject bad conversions now. */
7127 /* else continue to get conversion error. */
7128 }
7130 /* N3276 magic doesn't apply to nested calls. */
7134 /* Find maximum size of vector to hold converted arguments. */
7141 /* The implicit parameters to a constructor are not considered by overload
7142 resolution, and must be of the proper type. */
7144 {
7145 tree object_arg;
7147 {
7150 }
7151 else
7152 {
7155 }
7158 /* We should never try to call the abstract constructor. */
7162 {
7166 }
7167 }
7168 /* Bypass access control for 'this' parameter. */
7170 {
7173 ? first_arg
7176 tree converted_arg;
7177 tree base_binfo;
7180 {
7182 {
7187 }
7188 else
7190 }
7192 /* See if the function member or the whole class type is declared
7193 final and the call can be devirtualized. */
7198 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7199 X is called for an object that is not of type X, or of a type
7200 derived from X, the behavior is undefined.
7202 So we can assume that anything passed as 'this' is non-null, and
7203 optimize accordingly. */
7205 /* Convert to the base in which the function was declared. */
7208 arg,
7211 /* Check that the base class is accessible. */
7214 {
7219 else
7221 }
7222 /* If fn was found by a using declaration, the conversion path
7223 will be to the derived class, not the base declaring fn. We
7224 must convert from derived to base. */
7235 else
7239 }
7244 {
7251 /* If the argument is NULL and used to (implicitly) instantiate a
7252 template function (and bind one of the template arguments to
7253 the type of 'long int'), we don't want to warn about passing NULL
7254 to non-pointer argument.
7255 For example, if we have this template function:
7257 template<typename T> void func(T x) {}
7259 we want to warn (when -Wconversion is enabled) in this case:
7261 void foo() {
7262 func<int>(NULL);
7263 }
7265 but not in this case:
7267 void foo() {
7268 func(NULL);
7269 }
7270 */
7277 /* Warn about initializer_list deduction that isn't currently in the
7278 working draft. */
7280 && flag_deduce_init_list
7284 {
7297 {
7304 }
7305 }
7307 conversion_warning
7308 ? complain
7315 else
7317 }
7319 /* Default arguments */
7321 {
7327 complain);
7328 }
7330 /* Ellipsis */
7332 {
7335 /* Do no conversions for magic varargs. */
7340 {
7341 /* Avoid infinite recursion trying to call A(...). */
7343 /* Try to call the actual copy constructor for a good error. */
7346 }
7347 else
7350 }
7357 /* Avoid actually calling copy constructors and copy assignment operators,
7358 if possible. */
7365 /* It's unsafe to elide the constructor when handling
7366 a noexcept-expression, it may evaluate to the wrong
7367 value (c++/53025). */
7369 {
7370 tree targ;
7372 tree fa;
7375 /* Pull out the real argument, disregarding const-correctness. */
7381 {
7386 }
7387 else
7392 else
7395 /* [class.copy]: the copy constructor is implicitly defined even if
7396 the implementation elided its use. */
7398 {
7402 }
7404 /* If we're creating a temp and we already have one, don't create a
7405 new one. If we're not creating a temp but we get one, use
7406 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7407 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7408 temp or an INIT_EXPR otherwise. */
7411 {
7416 }
7418 {
7420 complain));
7424 }
7425 }
7429 {
7430 tree to = stabilize_reference
7437 {
7438 /* Avoid copying empty classes. */
7443 }
7445 {
7448 }
7449 else
7450 {
7451 /* We must only copy the non-tail padding parts. */
7459 build_index_type
7468 }
7471 }
7476 /* FIXME handle trivial default constructor, too. */
7478 /* For calls to a multi-versioned function, overload resolution
7479 returns the function with the highest target priority, that is,
7480 the version that will checked for dispatching first. If this
7481 version is inlinable, a direct call to this version can be made
7482 otherwise the call should go through the dispatcher. */
7487 {
7493 }
7500 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7501 virtual functions can't be constexpr. */
7503 {
7504 tree t;
7511 complain);
7517 else
7520 }
7521 else
7522 {
7526 }
7533 }
7535 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7536 This function performs no overload resolution, conversion, or other
7537 high-level operations. */
7539 tree
7541 tsubst_flags_t complain)
7542 {
7543 tree fndecl;
7546 /* Remember roughly where this call is. */
7553 /* Check that arguments to builtin functions match the expectations. */
7560 /* If it is a built-in array notation function, then the return type of
7561 the function is the element type of the array passed in as array
7562 notation (i.e. the first parameter of the function). */
7564 {
7573 {
7575 {
7578 }
7579 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7580 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7581 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7582 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7583 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7584 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7585 The pre-defined return-type is the correct one. */
7589 }
7590 }
7592 /* Some built-in function calls will be evaluated at compile-time in
7593 fold (). Set optimize to 1 when folding __builtin_constant_p inside
7594 a constexpr function so that fold_builtin_1 doesn't fold it to 0. */
7597 && current_function_decl
7606 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7607 function call is either the operand of a decltype-specifier or the
7608 right operand of a comma operator that is the operand of a
7609 decltype-specifier, a temporary object is not introduced for the
7610 prvalue. The type of the prvalue may be incomplete. */
7612 {
7619 }
7621 }
7625 /* Make an expression which yields the address of the Java interface
7626 method FN. This is achieved by generating a call to libjava's
7627 _Jv_LookupInterfaceMethodIdx(). */
7629 static tree
7631 {
7637 {
7641 java_iface_lookup_fn
7644 }
7646 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7647 This is the first entry in the vtable. */
7649 tf_warning_or_error),
7650 integer_zero_node);
7652 /* Get the java.lang.Class pointer for the interface being called. */
7657 {
7659 iface);
7661 }
7665 /* Determine the itable index of FN. */
7668 {
7673 i++;
7674 }
7679 java_iface_lookup_fn);
7682 }
7684 /* Returns the value to use for the in-charge parameter when making a
7685 call to a function with the indicated NAME.
7687 FIXME:Can't we find a neater way to do this mapping? */
7689 tree
7691 {
7702 /* This function should only be called with one of the names listed
7703 above. */
7706 }
7708 /* Build a call to a constructor, destructor, or an assignment
7709 operator for INSTANCE, an expression with class type. NAME
7710 indicates the special member function to call; *ARGS are the
7711 arguments. ARGS may be NULL. This may change ARGS. BINFO
7712 indicates the base of INSTANCE that is to be passed as the `this'
7713 parameter to the member function called.
7715 FLAGS are the LOOKUP_* flags to use when processing the call.
7717 If NAME indicates a complete object constructor, INSTANCE may be
7718 NULL_TREE. In this case, the caller will call build_cplus_new to
7719 store the newly constructed object into a VAR_DECL. */
7721 tree
7724 {
7725 tree fns;
7726 /* The type of the subobject to be constructed or destroyed. */
7727 tree class_type;
7729 tree ret;
7738 {
7739 /* Resolve the name. */
7744 }
7750 /* Handle the special case where INSTANCE is NULL_TREE. */
7753 else
7754 {
7760 /* Convert to the base class, if necessary. */
7763 {
7765 /* For constructors and destructors, either the base is
7766 non-virtual, or it is virtual but we are doing the
7767 conversion from a constructor or destructor for the
7768 complete object. In either case, we can convert
7769 statically. */
7771 else
7772 /* However, for assignment operators, we must convert
7773 dynamically if the base is virtual. */
7776 }
7777 }
7783 /* When making a call to a constructor or destructor for a subobject
7784 that uses virtual base classes, pass down a pointer to a VTT for
7785 the subobject. */
7789 {
7790 tree vtt;
7791 tree sub_vtt;
7793 /* If the current function is a complete object constructor
7794 or destructor, then we fetch the VTT directly.
7795 Otherwise, we look it up using the VTT we were given. */
7803 current_vtt_parm,
7804 vtt);
7807 else
7811 {
7814 }
7817 }
7822 complain);
7836 }
7838 /* Return the NAME, as a C string. The NAME indicates a function that
7839 is a member of TYPE. *FREE_P is set to true if the caller must
7840 free the memory returned.
7842 Rather than go through all of this, we should simply set the names
7843 of constructors and destructors appropriately, and dispense with
7844 ctor_identifier, dtor_identifier, etc. */
7848 {
7851 /* Assume that we will not allocate memory. */
7853 /* Constructors and destructors are special. */
7855 {
7856 pretty_name
7858 /* For a destructor, add the '~'. */
7862 {
7864 /* Remember that we need to free the memory allocated. */
7866 }
7867 }
7869 {
7872 TFF_PLAIN_IDENTIFIER),
7873 NULL);
7874 /* Remember that we need to free the memory allocated. */
7876 }
7877 else
7881 }
7883 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
7884 be set, upon return, to the function called. ARGS may be NULL.
7885 This may change ARGS. */
7887 static tree
7891 {
7896 tree optype;
7898 tree name;
7901 tree call;
7902 tree fn;
7905 tree orig_instance;
7906 tree orig_fns;
7912 /* We don't know what function we're going to call, yet. */
7921 {
7925 }
7930 /* Dismantle the baselink to collect all the information we need. */
7938 {
7942 }
7953 {
7958 }
7961 /* Under DR 147 A::A() is an invalid constructor call,
7962 not a functional cast. */
7964 {
7974 complain);
7976 }
7978 /* Figure out whether to skip the first argument for the error
7979 message we will display to users if an error occurs. We don't
7980 want to display any compiler-generated arguments. The "this"
7981 pointer hasn't been added yet. However, we must remove the VTT
7982 pointer if this is a call to a base-class constructor or
7983 destructor. */
7986 {
7987 /* Callers should explicitly indicate whether they want to construct
7988 the complete object or just the part without virtual bases. */
7990 /* Similarly for destructors. */
7992 /* Remove the VTT pointer, if present. */
7996 }
7998 /* Process the argument list. */
8000 {
8004 }
8006 /* Consider the object argument to be used even if we end up selecting a
8007 static member function. */
8010 /* It's OK to call destructors and constructors on cv-qualified objects.
8011 Therefore, convert the INSTANCE to the unqualified type, if
8012 necessary. */
8015 {
8017 {
8021 }
8022 }
8026 /* For the overload resolution we need to find the actual `this`
8027 that would be captured if the call turns out to be to a
8028 non-static member function. Do not actually capture it at this
8029 point. */
8031 /* Constructors don't use the enclosing 'this'. */
8033 else
8036 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8039 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8040 initializer, not T({ }). */
8043 {
8050 /* If the initializer list has no elements and T is a class type with
8051 a default constructor, the object is value-initialized. Handle
8052 this here so we don't need to handle it wherever we use
8053 build_special_member_call. */
8056 /* For a user-provided default constructor, use the normal
8057 mechanisms so that protected access works. */
8062 /* If BASETYPE is an aggregate, we need to do aggregate
8063 initialization. */
8068 {
8074 }
8076 /* Otherwise go ahead with overload resolution. */
8081 }
8082 else
8083 {
8087 }
8092 {
8094 {
8101 else
8102 {
8105 tree arglist;
8116 }
8118 }
8120 }
8121 else
8122 {
8125 {
8128 tree arglist;
8131 {
8139 else
8145 }
8147 }
8148 else
8149 {
8157 {
8158 /* This is not an error, it is runtime undefined
8159 behavior. */
8168 fn);
8169 }
8174 {
8179 {
8180 /* We captured 'this' in the current lambda now that
8181 we know we really need it. */
8183 }
8184 else
8185 {
8188 fn);
8190 }
8191 }
8194 {
8195 /* Optimize away vtable lookup if we know that this
8196 function can't be overridden. We need to check if
8197 the context and the type where we found fn are the same,
8198 actually FN might be defined in a different class
8199 type because of a using-declaration. In this case, we
8200 do not want to perform a non-virtual call. */
8202 && same_type_ignoring_top_level_qualifiers_p
8208 /* Now we know what function is being called. */
8211 /* Build the actual CALL_EXPR. */
8213 /* In an expression of the form `a->f()' where `f' turns
8214 out to be a static member function, `a' is
8215 none-the-less evaluated. */
8224 /* An explicit call of the form "x->~X()" has type
8225 "void". However, on platforms where destructors
8226 return "this" (i.e., those where
8227 targetm.cxx.cdtor_returns_this is true), such calls
8228 will appear to have a return value of pointer type
8229 to the low-level call machinery. We do not want to
8230 change the low-level machinery, since we want to be
8231 able to optimize "delete f()" on such platforms as
8232 "operator delete(~X(f()))" (rather than generating
8233 "t = f(), ~X(t), operator delete (t)"). */
8235 }
8236 }
8237 }
8240 {
8246 {
8249 }
8252 call = (build_min_non_dep_call_vec
8256 orig_args));
8261 }
8263 /* Free all the conversions we allocated. */
8270 }
8272 /* Wrapper for above. */
8274 tree
8278 {
8279 tree ret;
8285 }
8287 /* Returns true iff standard conversion sequence ICS1 is a proper
8288 subsequence of ICS2. */
8290 static bool
8292 {
8293 /* We can assume that a conversion of the same code
8294 between the same types indicates a subsequence since we only get
8295 here if the types we are converting from are the same. */
8302 {
8312 /* At this point, ICS1 cannot be a proper subsequence of
8313 ICS2. We can get a USER_CONV when we are comparing the
8314 second standard conversion sequence of two user conversion
8315 sequences. */
8325 }
8326 }
8328 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8329 be any _TYPE nodes. */
8331 bool
8333 {
8337 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8338 considers every class derived from itself. */
8341 }
8343 /* We build the ICS for an implicit object parameter as a pointer
8344 conversion sequence. However, such a sequence should be compared
8345 as if it were a reference conversion sequence. If ICS is the
8346 implicit conversion sequence for an implicit object parameter,
8347 modify it accordingly. */
8349 static void
8351 {
8353 {
8354 /* [over.match.funcs]
8356 For non-static member functions, the type of the
8357 implicit object parameter is "reference to cv X"
8358 where X is the class of which the function is a
8359 member and cv is the cv-qualification on the member
8360 function declaration. */
8362 tree reference_type;
8364 /* The `this' parameter is a pointer to a class type. Make the
8365 implicit conversion talk about a reference to that same class
8366 type. */
8379 }
8380 }
8382 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8383 and return the initial reference binding conversion. Otherwise,
8384 leave *ICS unchanged and return NULL. */
8388 {
8390 {
8395 }
8398 }
8400 /* Compare two implicit conversion sequences according to the rules set out in
8401 [over.ics.rank]. Return values:
8403 1: ics1 is better than ics2
8404 -1: ics2 is better than ics1
8405 0: ics1 and ics2 are indistinguishable */
8407 static int
8409 {
8410 tree from_type1;
8411 tree from_type2;
8412 tree to_type1;
8413 tree to_type2;
8420 /* REF_BINDING is nonzero if the result of the conversion sequence
8421 is a reference type. In that case REF_CONV is the reference
8422 binding conversion. */
8426 /* Compare badness before stripping the reference conversion. */
8432 /* Handle implicit object parameters. */
8436 /* Handle reference parameters. */
8440 /* List-initialization sequence L1 is a better conversion sequence than
8441 list-initialization sequence L2 if L1 converts to
8442 std::initializer_list<X> for some X and L2 does not. */
8448 /* [over.ics.rank]
8450 When comparing the basic forms of implicit conversion sequences (as
8451 defined in _over.best.ics_)
8453 --a standard conversion sequence (_over.ics.scs_) is a better
8454 conversion sequence than a user-defined conversion sequence
8455 or an ellipsis conversion sequence, and
8457 --a user-defined conversion sequence (_over.ics.user_) is a
8458 better conversion sequence than an ellipsis conversion sequence
8459 (_over.ics.ellipsis_). */
8460 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8461 mismatch. If both ICS are bad, we try to make a decision based on
8462 what would have happened if they'd been good. This is not an
8463 extension, we'll still give an error when we build up the call; this
8464 just helps us give a more helpful error message. */
8474 /* Both conversions are ellipsis conversions. */
8477 /* User-defined conversion sequence U1 is a better conversion sequence
8478 than another user-defined conversion sequence U2 if they contain the
8479 same user-defined conversion operator or constructor and if the sec-
8480 ond standard conversion sequence of U1 is better than the second
8481 standard conversion sequence of U2. */
8483 /* Handle list-conversion with the same code even though it isn't always
8484 ranked as a user-defined conversion and it doesn't have a second
8485 standard conversion sequence; it will still have the desired effect.
8486 Specifically, we need to do the reference binding comparison at the
8487 end of this function. */
8490 {
8506 {
8509 }
8510 else
8511 {
8512 /* For ambiguous or aggregate conversions, use the target type as
8513 a proxy for the conversion function. */
8516 }
8518 /* We can just fall through here, after setting up
8519 FROM_TYPE1 and FROM_TYPE2. */
8522 }
8523 else
8524 {
8528 /* We're dealing with two standard conversion sequences.
8530 [over.ics.rank]
8532 Standard conversion sequence S1 is a better conversion
8533 sequence than standard conversion sequence S2 if
8535 --S1 is a proper subsequence of S2 (comparing the conversion
8536 sequences in the canonical form defined by _over.ics.scs_,
8537 excluding any Lvalue Transformation; the identity
8538 conversion sequence is considered to be a subsequence of
8539 any non-identity conversion sequence */
8550 }
8552 /* One sequence can only be a subsequence of the other if they start with
8553 the same type. They can start with different types when comparing the
8554 second standard conversion sequence in two user-defined conversion
8555 sequences. */
8557 {
8562 }
8564 /* [over.ics.rank]
8566 Or, if not that,
8568 --the rank of S1 is better than the rank of S2 (by the rules
8569 defined below):
8571 Standard conversion sequences are ordered by their ranks: an Exact
8572 Match is a better conversion than a Promotion, which is a better
8573 conversion than a Conversion.
8575 Two conversion sequences with the same rank are indistinguishable
8576 unless one of the following rules applies:
8578 --A conversion that does not a convert a pointer, pointer to member,
8579 or std::nullptr_t to bool is better than one that does.
8581 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8582 so that we do not have to check it explicitly. */
8591 /* A conversion from scalar arithmetic type to complex is worse than a
8592 conversion between scalar arithmetic types. */
8599 {
8602 else
8604 }
8610 {
8615 }
8616 /* The rules for pointers to members A::* are just like the rules
8617 for pointers A*, except opposite: if B is derived from A then
8618 A::* converts to B::*, not vice versa. For that reason, we
8619 switch the from_ and to_ variables here. */
8626 {
8631 }
8636 {
8637 /* This was one of the pointer or pointer-like conversions.
8639 [over.ics.rank]
8641 --If class B is derived directly or indirectly from class A,
8642 conversion of B* to A* is better than conversion of B* to
8643 void*, and conversion of A* to void* is better than
8644 conversion of B* to void*. */
8647 {
8649 deref_from_type2))
8652 deref_from_type1))
8654 }
8657 {
8659 {
8661 {
8663 deref_to_type1))
8665 }
8666 /* We know that DEREF_TO_TYPE1 is `void' here. */
8668 deref_to_type2))
8670 }
8671 }
8674 {
8675 /* [over.ics.rank]
8677 --If class B is derived directly or indirectly from class A
8678 and class C is derived directly or indirectly from B,
8680 --conversion of C* to B* is better than conversion of C* to
8681 A*,
8683 --conversion of B* to A* is better than conversion of C* to
8684 A* */
8686 {
8688 deref_to_type2))
8691 deref_to_type1))
8693 }
8695 {
8697 deref_from_type1))
8700 deref_from_type2))
8702 }
8703 }
8704 }
8707 {
8710 /* [over.ics.rank]
8712 --binding of an expression of type C to a reference of type
8713 B& is better than binding an expression of type C to a
8714 reference of type A&
8716 --conversion of C to B is better than conversion of C to A, */
8719 {
8724 }
8725 }
8728 {
8731 /* [over.ics.rank]
8733 --binding of an expression of type B to a reference of type
8734 A& is better than binding an expression of type C to a
8735 reference of type A&,
8737 --conversion of B to A is better than conversion of C to A */
8740 {
8745 }
8746 }
8748 /* [over.ics.rank]
8750 --S1 and S2 differ only in their qualification conversion and yield
8751 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8752 qualification signature of type T1 is a proper subset of the cv-
8753 qualification signature of type T2 */
8757 {
8761 }
8763 /* [over.ics.rank]
8765 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8766 to an implicit object parameter of a non-static member function
8767 declared without a ref-qualifier, and either S1 binds an lvalue
8768 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8769 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8770 draft standard, 13.3.3.2)
8772 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8773 types to which the references refer are the same type except for
8774 top-level cv-qualifiers, and the type to which the reference
8775 initialized by S2 refers is more cv-qualified than the type to
8776 which the reference initialized by S1 refers.
8778 DR 1328 [over.match.best]: the context is an initialization by
8779 conversion function for direct reference binding (13.3.1.6) of a
8780 reference to function type, the return type of F1 is the same kind of
8781 reference (i.e. lvalue or rvalue) as the reference being initialized,
8782 and the return type of F2 is not. */
8785 {
8792 {
8796 /* Don't prefer a bad conversion that drops cv-quals to a bad
8797 conversion with the wrong rvalueness. */
8801 }
8804 {
8808 {
8809 /* Prefer the one that drops fewer cv-quals. */
8814 }
8816 }
8817 }
8819 /* Neither conversion sequence is better than the other. */
8821 }
8823 /* The source type for this standard conversion sequence. */
8825 static tree
8827 {
8829 {
8834 }
8836 }
8838 /* Note a warning about preferring WINNER to LOSER. We do this by storing
8839 a pointer to LOSER and re-running joust to produce the warning if WINNER
8840 is actually used. */
8842 static void
8844 {
8850 }
8852 /* Compare two candidates for overloading as described in
8853 [over.match.best]. Return values:
8855 1: cand1 is better than cand2
8856 -1: cand2 is better than cand1
8857 0: cand1 and cand2 are indistinguishable */
8859 static int
8861 tsubst_flags_t complain)
8862 {
8868 /* Candidates that involve bad conversions are always worse than those
8869 that don't. */
8875 /* If we have two pseudo-candidates for conversions to the same type,
8876 or two candidates for the same function, arbitrarily pick one. */
8881 /* Prefer a non-deleted function over an implicitly deleted move
8882 constructor or assignment operator. This differs slightly from the
8883 wording for issue 1402 (which says the move op is ignored by overload
8884 resolution), but this way produces better error messages. */
8888 {
8895 }
8897 /* a viable function F1
8898 is defined to be a better function than another viable function F2 if
8899 for all arguments i, ICSi(F1) is not a worse conversion sequence than
8900 ICSi(F2), and then */
8902 /* for some argument j, ICSj(F1) is a better conversion sequence than
8903 ICSj(F2) */
8905 /* For comparing static and non-static member functions, we ignore
8906 the implicit object parameter of the non-static function. The
8907 standard says to pretend that the static function has an object
8908 parm, but that won't work with operator overloading. */
8911 {
8917 /* We're comparing a near-match list constructor and a near-match
8918 non-list constructor. Just treat them as unordered. */
8925 else
8926 {
8929 }
8930 }
8933 {
8939 {
8941 && warn_sign_promo
8953 {
8960 else
8965 {
8969 }
8970 else
8972 }
8975 {
8978 }
8980 }
8981 }
8983 /* warn about confusing overload resolution for user-defined conversions,
8984 either between a constructor and a conversion op, or between two
8985 conversion ops. */
8990 {
8996 else
8999 /* We don't want to complain about `X::operator T1 ()'
9000 beating `X::operator T2 () const', when T2 is a no less
9001 cv-qualified version of T1. */
9004 {
9009 {
9012 }
9015 }
9016 else
9022 {
9029 {
9031 }
9032 }
9033 else
9035 }
9040 /* DR 495 moved this tiebreaker above the template ones. */
9041 /* or, if not that,
9042 the context is an initialization by user-defined conversion (see
9043 _dcl.init_ and _over.match.user_) and the standard conversion
9044 sequence from the return type of F1 to the destination type (i.e.,
9045 the type of the entity being initialized) is a better conversion
9046 sequence than the standard conversion sequence from the return type
9047 of F2 to the destination type. */
9050 {
9054 }
9056 /* or, if not that,
9057 F1 is a non-template function and F2 is a template function
9058 specialization. */
9065 /* or, if not that,
9066 F1 and F2 are template functions and the function template for F1 is
9067 more specialized than the template for F2 according to the partial
9068 ordering rules. */
9071 {
9072 winner = more_specialized_fn
9075 /* [temp.func.order]: The presence of unused ellipsis and default
9076 arguments has no effect on the partial ordering of function
9077 templates. add_function_candidate() will not have
9078 counted the "this" argument for constructors. */
9082 }
9084 /* Check whether we can discard a builtin candidate, either because we
9085 have two identical ones or matching builtin and non-builtin candidates.
9087 (Pedantically in the latter case the builtin which matched the user
9088 function should not be added to the overload set, but we spot it here.
9090 [over.match.oper]
9091 ... the builtin candidates include ...
9092 - do not have the same parameter type list as any non-template
9093 non-member candidate. */
9096 {
9102 {
9104 /* Two built-in candidates; arbitrarily pick one. */
9107 /* cand1 is built-in; prefer cand2. */
9109 else
9110 /* cand2 is built-in; prefer cand1. */
9112 }
9113 }
9115 /* For candidates of a multi-versioned function, make the version with
9116 the highest priority win. This version will be checked for dispatching
9117 first. If this version can be inlined into the caller, the front-end
9118 will simply make a direct call to this function. */
9124 {
9130 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9131 is possible that cand1->fn and cand2->fn are function versions but of
9132 different functions. Check types to see if they are versions of the same
9133 function. */
9136 {
9137 /* Always make the version with the higher priority, more
9138 specialized, win. */
9142 else
9144 }
9145 }
9147 /* If the two function declarations represent the same function (this can
9148 happen with declarations in multiple scopes and arg-dependent lookup),
9149 arbitrarily choose one. But first make sure the default args we're
9150 using match. */
9153 {
9160 {
9161 /* Don't crash if the fn is variadic. */
9166 }
9174 {
9177 {
9179 {
9181 {
9183 "default argument mismatch in "
9185 {
9190 }
9191 }
9192 else
9194 }
9195 else
9198 }
9201 }
9204 }
9206 tweak:
9208 /* Extension: If the worst conversion for one candidate is worse than the
9209 worst conversion for the other, take the first. */
9211 {
9216 {
9221 }
9227 {
9228 /* Don't choose a deleted function over ambiguity. */
9232 {
9234 "ISO C++ says that these are ambiguous, even "
9235 "though the worst conversion for the first is better than "
9239 }
9240 else
9243 }
9244 }
9248 }
9250 /* Given a list of candidates for overloading, find the best one, if any.
9251 This algorithm has a worst case of O(2n) (winner is last), and a best
9252 case of O(n/2) (totally ambiguous); much better than a sorting
9253 algorithm. */
9257 {
9262 /* Walk through the list once, comparing each current champ to the next
9263 candidate, knocking out a candidate or two with each comparison. */
9266 {
9270 else
9271 {
9273 {
9278 }
9279 else
9280 {
9283 }
9286 }
9287 }
9289 /* Make sure the champ is better than all the candidates it hasn't yet
9290 been compared to. */
9293 challenger != champ
9296 {
9300 }
9303 }
9305 /* Returns nonzero if things of type FROM can be converted to TO. */
9307 bool
9309 {
9311 /* implicit_conversion only considers user-defined conversions
9312 if it has an expression for the call argument list. */
9316 }
9318 /* Returns nonzero if things of type FROM can be converted to TO with a
9319 standard conversion. */
9321 bool
9323 {
9325 }
9327 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9329 bool
9331 tsubst_flags_t complain)
9332 {
9337 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9339 /* We want to discard any access checks done for this test,
9340 as we might not be in the appropriate access context and
9341 we'll do the check again when we actually perform the
9342 conversion. */
9349 /* Discard the access checks now. */
9351 /* Free all the conversions we allocated. */
9355 }
9357 /* Like can_convert_arg, but allows dubious conversions as well. */
9359 bool
9361 tsubst_flags_t complain)
9362 {
9366 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9368 /* Try to perform the conversion. */
9371 /* Free all the conversions we allocated. */
9375 }
9377 /* Convert EXPR to TYPE. Return the converted expression.
9379 Note that we allow bad conversions here because by the time we get to
9380 this point we are committed to doing the conversion. If we end up
9381 doing a bad conversion, convert_like will complain. */
9383 tree
9386 {
9394 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9402 {
9404 {
9405 /* If expr has unknown type, then it is an overloaded function.
9406 Call instantiate_type to get good error messages. */
9411 else
9414 }
9416 }
9418 {
9419 /* In a template, we are only concerned about determining the
9420 type of non-dependent expressions, so we do not have to
9421 perform the actual conversion. But for initializers, we
9422 need to be able to perform it at instantiation
9423 (or instantiate_non_dependent_expr) time. */
9427 }
9428 else
9431 /* Free all the conversions we allocated. */
9435 }
9437 tree
9439 {
9441 LOOKUP_IMPLICIT);
9442 }
9444 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9445 permitted. If the conversion is valid, the converted expression is
9446 returned. Otherwise, NULL_TREE is returned, except in the case
9447 that TYPE is a class type; in that case, an error is issued. If
9448 C_CAST_P is true, then this direct-initialization is taking
9449 place as part of a static_cast being attempted as part of a C-style
9450 cast. */
9452 tree
9454 tree expr,
9456 tsubst_flags_t complain)
9457 {
9463 /* [dcl.init]
9465 If the destination type is a (possibly cv-qualified) class type:
9467 -- If the initialization is direct-initialization ...,
9468 constructors are considered. ... If no constructor applies, or
9469 the overload resolution is ambiguous, the initialization is
9470 ill-formed. */
9472 {
9478 }
9480 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9484 c_cast_p,
9488 else
9491 c_cast_p,
9492 complain);
9494 /* Free all the conversions we allocated. */
9498 }
9500 /* When initializing a reference that lasts longer than a full-expression,
9501 this special rule applies:
9503 [class.temporary]
9505 The temporary to which the reference is bound or the temporary
9506 that is the complete object to which the reference is bound
9507 persists for the lifetime of the reference.
9509 The temporaries created during the evaluation of the expression
9510 initializing the reference, except the temporary to which the
9511 reference is bound, are destroyed at the end of the
9512 full-expression in which they are created.
9514 In that case, we store the converted expression into a new
9515 VAR_DECL in a new scope.
9517 However, we want to be careful not to create temporaries when
9518 they are not required. For example, given:
9520 struct B {};
9521 struct D : public B {};
9522 D f();
9523 const B& b = f();
9525 there is no need to copy the return value from "f"; we can just
9526 extend its lifetime. Similarly, given:
9528 struct S {};
9529 struct T { operator S(); };
9530 T t;
9531 const S& s = t;
9533 we can extend the lifetime of the return value of the conversion
9534 operator.
9536 The next several functions are involved in this lifetime extension. */
9538 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9539 reference is being bound to a temporary. Create and return a new
9540 VAR_DECL with the indicated TYPE; this variable will store the value to
9541 which the reference is bound. */
9543 tree
9545 {
9546 tree var;
9548 /* Create the variable. */
9551 /* Register the variable. */
9554 {
9555 /* Namespace-scope or local static; give it a mangled name. */
9556 /* FIXME share comdat with decl? */
9557 tree name;
9565 }
9566 else
9567 /* Create a new cleanup level if necessary. */
9571 }
9573 /* EXPR is the initializer for a variable DECL of reference or
9574 std::initializer_list type. Create, push and return a new VAR_DECL
9575 for the initializer so that it will live as long as DECL. Any
9576 cleanup for the new variable is returned through CLEANUP, and the
9577 code to initialize the new variable is returned through INITP. */
9579 static tree
9582 {
9583 tree init;
9584 tree type;
9585 tree var;
9587 /* Create the temporary variable. */
9591 /* If the rvalue is the result of a function call it will be
9592 a TARGET_EXPR. If it is some other construct (such as a
9593 member access expression where the underlying object is
9594 itself the result of a function call), turn it into a
9595 TARGET_EXPR here. It is important that EXPR be a
9596 TARGET_EXPR below since otherwise the INIT_EXPR will
9597 attempt to make a bitwise copy of EXPR to initialize
9598 VAR. */
9604 {
9608 }
9610 /* Recursively extend temps in this initializer. */
9614 /* Any reference temp has a non-trivial initializer. */
9617 /* If the initializer is constant, put it in DECL_INITIAL so we get
9618 static initialization and use in constant expressions. */
9621 {
9623 {
9624 /* 5.19 says that a constant expression can include an
9625 lvalue-rvalue conversion applied to "a glvalue of literal type
9626 that refers to a non-volatile temporary object initialized
9627 with a constant expression". Rather than try to communicate
9628 that this VAR_DECL is a temporary, just mark it constexpr.
9630 Currently this is only useful for initializer_list temporaries,
9631 since reference vars can't appear in constant expressions. */
9635 }
9638 }
9639 else
9640 /* Create the INIT_EXPR that will initialize the temporary
9641 variable. */
9644 {
9649 else
9650 {
9654 }
9656 /* We must be careful to destroy the temporary only
9657 after its initialization has taken place. If the
9658 initialization throws an exception, then the
9659 destructor should not be run. We cannot simply
9660 transform INIT into something like:
9662 (INIT, ({ CLEANUP_STMT; }))
9664 because emit_local_var always treats the
9665 initializer as a full-expression. Thus, the
9666 destructor would run too early; it would run at the
9667 end of initializing the reference variable, rather
9668 than at the end of the block enclosing the
9669 reference variable.
9671 The solution is to pass back a cleanup expression
9672 which the caller is responsible for attaching to
9673 the statement tree. */
9674 }
9675 else
9676 {
9679 {
9682 tls_aggregates);
9683 else
9685 static_aggregates);
9686 }
9687 else
9688 /* Check whether the dtor is callable. */
9690 }
9691 /* Avoid -Wunused-variable warning (c++/38958). */
9698 }
9700 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9701 initializing a variable of that TYPE. */
9703 tree
9706 {
9714 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9720 {
9722 {
9731 else
9735 }
9737 }
9740 /* Perform the conversion. */
9743 /* We gave an error in build_user_type_conversion_1. */
9745 else
9748 /* Free all the conversions we allocated. */
9752 }
9754 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9755 which is bound either to a reference or a std::initializer_list. */
9757 static tree
9759 {
9764 {
9768 }
9771 /* Deal with binding to a subobject. */
9775 {
9783 }
9785 }
9787 /* INIT is part of the initializer for DECL. If there are any
9788 reference or initializer lists being initialized, extend their
9789 lifetime to match that of DECL. */
9791 tree
9793 {
9800 {
9801 /* The temporary array underlying a std::initializer_list
9802 is handled like a reference temporary. */
9807 {
9811 }
9812 }
9814 {
9820 }
9823 }
9825 /* Returns true iff an initializer for TYPE could contain temporaries that
9826 need to be extended because they are bound to references or
9827 std::initializer_list. */
9829 bool
9831 {
9836 {
9843 }
9845 }
9847 /* Returns true iff TYPE is some variant of std::initializer_list. */
9849 bool
9851 {
9852 /* Look through typedefs. */
9861 }
9863 /* Returns true iff DECL is a list constructor: i.e. a constructor which
9864 will accept an argument list of a single std::initializer_list<T>. */
9866 bool
9868 {
9870 tree arg;
9882 /* There are more non-defaulted parms. */
9886 }