| blob | 88af0d31446d511f49c407c0017dd33d2fe84d26 |
1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2017 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. */
45 /* The various kinds of conversion. */
48 ck_identity,
49 ck_lvalue,
50 ck_fnptr,
51 ck_qual,
52 ck_std,
53 ck_ptr,
54 ck_pmem,
55 ck_base,
56 ck_ref_bind,
57 ck_user,
58 ck_ambig,
59 ck_list,
60 ck_aggr,
61 ck_rvalue
62 };
64 /* The rank of the conversion. Order of the enumerals matters; better
65 conversions should come earlier in the list. */
68 cr_identity,
69 cr_exact,
70 cr_promotion,
71 cr_std,
72 cr_pbool,
73 cr_user,
74 cr_ellipsis,
75 cr_bad
76 };
78 /* An implicit conversion sequence, in the sense of [over.best.ics].
79 The first conversion to be performed is at the end of the chain.
80 That conversion is always a cr_identity conversion. */
83 /* The kind of conversion represented by this step. */
84 conversion_kind kind;
85 /* The rank of this conversion. */
86 conversion_rank rank;
90 /* True if this conversion would be permitted with a bending of
91 language standards, e.g. disregarding pointer qualifiers or
92 converting integers to pointers. */
94 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
95 temporary should be created to hold the result of the
96 conversion. */
98 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
99 from a pointer-to-derived to pointer-to-base is being performed. */
101 /* If KIND is ck_ref_bind, true when either an lvalue reference is
102 being bound to an lvalue expression or an rvalue reference is
103 being bound to an rvalue expression. If KIND is ck_rvalue,
104 true when we are treating an lvalue as an rvalue (12.8p33). If
105 KIND is ck_base, always false. */
108 /* The type of the expression resulting from the conversion. */
109 tree type;
111 /* The next conversion in the chain. Since the conversions are
112 arranged from outermost to innermost, the NEXT conversion will
113 actually be performed before this conversion. This variant is
114 used only when KIND is neither ck_identity, ck_ambig nor
115 ck_list. Please use the next_conversion function instead
116 of using this field directly. */
118 /* The expression at the beginning of the conversion chain. This
119 variant is used only if KIND is ck_identity or ck_ambig. */
120 tree expr;
121 /* The array of conversions for an initializer_list, so this
122 variant is used only when KIN D is ck_list. */
125 /* The function candidate corresponding to this conversion
126 sequence. This field is only used if KIND is ck_user. */
128 };
130 #define CONVERSION_RANK(NODE) \
131 ((NODE)->bad_p ? cr_bad \
132 : (NODE)->ellipsis_p ? cr_ellipsis \
133 : (NODE)->user_conv_p ? cr_user \
134 : (NODE)->rank)
136 #define BAD_CONVERSION_RANK(NODE) \
137 ((NODE)->ellipsis_p ? cr_ellipsis \
138 : (NODE)->user_conv_p ? cr_user \
139 : (NODE)->rank)
148 tsubst_flags_t);
151 #define convert_like(CONV, EXPR, COMPLAIN) \
152 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, \
155 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
156 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), \
164 tsubst_flags_t);
176 static void add_builtin_candidates
179 static void add_builtin_candidate
183 static void build_builtin_candidate
193 tsubst_flags_t);
195 tsubst_flags_t);
215 tsubst_flags_t);
219 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
220 NAME can take many forms... */
222 bool
224 {
225 /* Just accept something we've already complained about. */
234 {
239 else
241 }
242 else
243 {
244 /* In the case of:
246 template <class T> struct S { ~S(); };
247 int i;
248 i.~S();
250 NAME will be a class template. */
253 }
258 }
260 /* We want the address of a function or method. We avoid creating a
261 pointer-to-member function. */
263 tree
265 {
268 /* We have to do these by hand to avoid real pointer to member
269 functions. */
271 {
273 {
277 complain);
278 }
280 }
281 else
285 }
287 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
288 POINTER_TYPE to those. Note, pointer to member function types
289 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
290 two variants. build_call_a is the primitive taking an array of
291 arguments, while build_call_n is a wrapper that handles varargs. */
293 tree
295 {
298 else
299 {
309 }
310 }
312 /* Update various flags in cfun and the call itself based on what is being
313 called. Split out of build_call_a so that bot_manip can use it too. */
315 void
317 {
321 /* We check both the decl and the type; a function may be known not to
322 throw without being declared throw(). */
336 }
338 tree
340 {
341 tree decl;
342 tree result_type;
343 tree fntype;
353 /* An rvalue has no cv-qualifiers. */
364 {
365 /* We invoke build_call directly for several library
366 functions. These may have been declared normally if
367 we're building libgcc, so we can't just check
368 DECL_ARTIFICIAL. */
373 }
380 && flag_new_inheriting_ctors
384 /* Pass arguments directly to the inherited constructor. */
387 /* Don't pass empty class objects by value. This is useful
388 for tags in STL, which are used to control overload resolution.
389 We don't need to handle other cases of copying empty classes. */
392 {
396 {
400 }
401 }
404 }
406 /* New overloading code. */
413 };
415 /* Information for providing diagnostics about why overloading failed. */
418 rr_none,
419 rr_arity,
420 rr_explicit_conversion,
421 rr_template_conversion,
422 rr_arg_conversion,
423 rr_bad_arg_conversion,
424 rr_template_unification,
425 rr_invalid_copy,
426 rr_inherited_ctor,
427 rr_constraint_failure
428 };
431 /* The index of the argument, 0-based. */
433 /* The actual argument or its type. */
434 tree from;
435 /* The type of the parameter. */
436 tree to_type;
437 };
442 /* Information about an arity mismatch. */
444 /* The expected number of arguments. */
446 /* The actual number of arguments in the call. */
448 /* Whether the call was a varargs call. */
451 /* Information about an argument conversion mismatch. */
453 /* Same, but for bad argument conversions. */
455 /* Information about template unification failures. These are the
456 parameters passed to fn_type_unification. */
458 tree tmpl;
459 tree explicit_targs;
463 tree return_type;
464 unification_kind_t strict;
467 /* Information about template instantiation failures. These are the
468 parameters passed to instantiate_template. */
470 tree tmpl;
471 tree targs;
474 };
477 /* The FUNCTION_DECL that will be called if this candidate is
478 selected by overload resolution. */
479 tree fn;
480 /* If not NULL_TREE, the first argument to use when calling this
481 function. */
482 tree first_arg;
483 /* The rest of the arguments to use when calling this function. If
484 there are no further arguments this may be NULL or it may be an
485 empty vector. */
487 /* The implicit conversion sequences for each of the arguments to
488 FN. */
490 /* The number of implicit conversion sequences. */
492 /* If FN is a user-defined conversion, the standard conversion
493 sequence from the type returned by FN to the desired destination
494 type. */
497 /* If FN is a member function, the binfo indicating the path used to
498 qualify the name of FN at the call site. This path is used to
499 determine whether or not FN is accessible if it is selected by
500 overload resolution. The DECL_CONTEXT of FN will always be a
501 (possibly improper) base of this binfo. */
502 tree access_path;
503 /* If FN is a non-static member function, the binfo indicating the
504 subobject to which the `this' pointer should be converted if FN
505 is selected by overload resolution. The type pointed to by
506 the `this' pointer must correspond to the most derived class
507 indicated by the CONVERSION_PATH. */
508 tree conversion_path;
509 tree template_decl;
510 tree explicit_targs;
515 /* The flags active in add_candidate. */
517 };
519 /* Returns true iff T is a null pointer constant in the sense of
520 [conv.ptr]. */
522 bool
524 {
527 /* [conv.ptr]
529 A null pointer constant is an integral constant expression
530 (_expr.const_) rvalue of integer type that evaluates to zero or
531 an rvalue of type std::nullptr_t. */
536 {
537 /* Core issue 903 says only literal 0 is a null pointer constant. */
544 }
546 {
551 }
554 }
556 /* Returns true iff T is a null member pointer value (4.11). */
558 bool
560 {
569 else
571 }
573 /* Returns nonzero if PARMLIST consists of only default parms,
574 ellipsis, and/or undeduced parameter packs. */
576 bool
578 {
585 }
587 /* Allocate N bytes of memory from the conversion obstack. The memory
588 is zeroed before being returned. */
592 {
595 {
598 }
602 }
604 /* Allocate rejection reasons. */
608 {
613 }
617 {
623 }
627 {
634 }
638 {
645 }
649 {
655 }
659 {
665 }
672 {
679 /* Copy args to our own storage. */
687 }
691 {
693 }
697 {
700 }
704 {
707 }
709 // Build a constraint failure record, saving information into the
710 // template_instantiation field of the rejection. If FN is not a template
711 // declaration, the TMPL member is the FN declaration and TARGS is empty.
715 {
718 {
721 }
722 else
723 {
726 }
728 }
730 /* Dynamically allocate a conversion. */
734 {
739 }
741 /* Make sure that all memory on the conversion obstack has been
742 freed. */
744 void
746 {
750 }
752 /* Dynamically allocate an array of N conversions. */
756 {
758 }
762 {
766 /* Note that the caller is responsible for filling in t->cand for
767 user-defined conversions. */
773 {
790 }
796 }
798 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
799 specialization of std::initializer_list<T>, if such a conversion is
800 possible. */
804 {
810 tree val;
812 /* Within a list-initialization we can have more user-defined
813 conversions. */
815 /* But no narrowing conversions. */
818 /* Can't make an array of these types. */
825 {
826 conversion *sub
833 }
841 {
849 }
852 }
854 /* Return the next conversion of the conversion chain (if applicable),
855 or NULL otherwise. Please use this function instead of directly
856 accessing fields of struct conversion. */
860 {
867 }
869 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
870 is a valid aggregate initializer for array type ATYPE. */
872 static bool
874 {
878 {
884 else
886 complain);
889 }
891 }
893 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
894 aggregate class, if such a conversion is possible. */
898 {
904 /* We already called reshape_init in implicit_conversion. */
906 /* The conversions within the init-list aren't affected by the enclosing
907 context; they're always simple copy-initialization. */
911 {
913 tree val;
921 /* Value-initialization of reference is ill-formed. */
923 else
924 {
928 }
934 else
936 complain);
943 }
955 }
957 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
958 array type, if such a conversion is possible. */
962 {
967 tree val;
972 /* We might need to propagate the size from the element to the array. */
977 {
981 }
986 {
987 conversion *sub
999 }
1008 }
1010 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1011 complex type, if such a conversion is possible. */
1015 tsubst_flags_t complain)
1016 {
1021 tree val;
1032 {
1033 conversion *sub
1045 }
1054 }
1056 /* Build a representation of the identity conversion from EXPR to
1057 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1061 {
1069 }
1071 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1072 were multiple user-defined conversions to accomplish the job.
1073 Build a conversion that indicates that ambiguity. */
1077 {
1085 }
1087 tree
1089 {
1093 }
1095 /* Returns the standard conversion path (see [conv]) from type FROM to type
1096 TO, if any. For proper handling of null pointer constants, you must
1097 also pass the expression EXPR to convert from. If C_CAST_P is true,
1098 this conversion is coming from a C-style cast. */
1103 {
1107 tree qualified_to;
1111 {
1114 }
1120 {
1122 {
1128 }
1130 {
1131 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1134 }
1135 }
1142 {
1146 }
1147 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1148 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1149 express the copy constructor call required by copy-initialization. */
1151 {
1153 {
1154 tree bitfield_type;
1157 {
1160 }
1161 }
1164 /* Tell convert_like_real to set LOOKUP_PREFER_RVALUE. */
1166 }
1168 /* Allow conversion between `__complex__' data types. */
1170 {
1171 /* The standard conversion sequence to convert FROM to TO is
1172 the standard conversion sequence to perform componentwise
1173 conversion. */
1176 complain);
1179 {
1182 }
1183 else
1187 }
1190 {
1194 }
1196 /* [conv.ptr]
1197 A null pointer constant can be converted to a pointer type; ... A
1198 null pointer constant of integral type can be converted to an
1199 rvalue of type std::nullptr_t. */
1207 {
1208 /* For backwards brain damage compatibility, allow interconversion of
1209 pointers and integers with a pedwarn. */
1212 }
1214 {
1215 /* For backwards brain damage compatibility, allow interconversion of
1216 enums and integers with a pedwarn. */
1219 }
1222 {
1223 tree to_pointee;
1224 tree from_pointee;
1227 {
1231 /* Since this is the target of a pointer, it can't have function
1232 qualifiers, so any TYPE_QUALS must be for attributes const or
1233 noreturn. Strip them. */
1240 }
1241 else
1242 {
1245 }
1249 to_pointee))
1250 ;
1254 {
1256 /* Don't try to apply restrict to void. */
1261 }
1263 {
1270 && (same_type_ignoring_top_level_qualifiers_p
1272 {
1275 }
1276 else
1278 }
1281 /* [conv.ptr]
1283 An rvalue of type "pointer to cv D," where D is a
1284 class type, can be converted to an rvalue of type
1285 "pointer to cv B," where B is a base class (clause
1286 _class.derived_) of D. If B is an inaccessible
1287 (clause _class.access_) or ambiguous
1288 (_class.member.lookup_) base class of D, a program
1289 that necessitates this conversion is ill-formed.
1290 Therefore, we use DERIVED_FROM_P, and do not check
1291 access or uniqueness. */
1293 {
1294 from_pointee
1300 }
1305 /* In a C-style cast, we ignore CV-qualification because we
1306 are allowed to perform a static_cast followed by a
1307 const_cast. */
1312 /* converting from string constant to char *. */
1316 /* Allow conversions among compatible ObjC pointer types (base
1317 conversions have been already handled above). */
1322 {
1325 }
1326 else
1330 }
1332 {
1346 else
1350 {
1352 tbase,
1358 }
1361 }
1363 {
1364 /* [conv.bool]
1366 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1367 to member type can be converted to a prvalue of type bool. ...
1368 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1369 std::nullptr_t can be converted to a prvalue of type bool; */
1375 {
1386 }
1389 }
1390 /* We don't check for ENUMERAL_TYPE here because there are no standard
1391 conversions to enum type. */
1392 /* As an extension, allow conversion to complex type. */
1394 {
1401 /* Give this a better rank if it's a promotion. */
1405 }
1411 {
1415 /* The derived-to-base conversion indicates the initialization
1416 of a parameter with base type from an object of a derived
1417 type. A temporary object is created to hold the result of
1418 the conversion unless we're binding directly to a reference. */
1420 }
1421 else
1428 }
1430 /* Returns nonzero if T1 is reference-related to T2. */
1432 bool
1434 {
1441 /* [dcl.init.ref]
1443 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1444 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1445 of T2. */
1449 }
1451 /* Returns nonzero if T1 is reference-compatible with T2. */
1453 static bool
1455 {
1456 /* [dcl.init.ref]
1458 "cv1 T1" is reference compatible with "cv2 T2" if
1459 * T1 is reference-related to T2 or
1460 * T2 is "noexcept function" and T1 is "function", where the
1461 function types are otherwise the same,
1462 and cv1 is the same cv-qualification as, or greater cv-qualification
1463 than, cv2. */
1467 }
1469 /* A reference of the indicated TYPE is being bound directly to the
1470 expression represented by the implicit conversion sequence CONV.
1471 Return a conversion sequence for this binding. */
1475 {
1476 tree t;
1483 /* [over.ics.rank]
1485 When a parameter of reference type binds directly
1486 (_dcl.init.ref_) to an argument expression, the implicit
1487 conversion sequence is the identity conversion, unless the
1488 argument expression has a type that is a derived class of the
1489 parameter type, in which case the implicit conversion sequence is
1490 a derived-to-base Conversion.
1492 If the parameter binds directly to the result of applying a
1493 conversion function to the argument expression, the implicit
1494 conversion sequence is a user-defined conversion sequence
1495 (_over.ics.user_), with the second standard conversion sequence
1496 either an identity conversion or, if the conversion function
1497 returns an entity of a type that is a derived class of the
1498 parameter type, a derived-to-base conversion. */
1500 {
1501 /* Represent the derived-to-base conversion. */
1503 /* We will actually be binding to the base-class subobject in
1504 the derived class, so we mark this conversion appropriately.
1505 That way, convert_like knows not to generate a temporary. */
1507 }
1509 }
1511 /* Returns the conversion path from type FROM to reference type TO for
1512 purposes of reference binding. For lvalue binding, either pass a
1513 reference type to FROM or an lvalue expression to EXPR. If the
1514 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1515 the conversion returned. If C_CAST_P is true, this
1516 conversion is coming from a C-style cast. */
1520 tsubst_flags_t complain)
1521 {
1525 tree tfrom;
1528 cp_lvalue_kind gl_kind;
1532 {
1537 }
1540 {
1542 /* DR 1288: Otherwise, if the initializer list has a single element
1543 of type E and ... [T's] referenced type is reference-related to E,
1544 the object or reference is initialized from that element... */
1546 {
1552 {
1556 }
1557 }
1558 /* Otherwise, if T is a reference type, a prvalue temporary of the
1559 type referenced by T is copy-list-initialized or
1560 direct-list-initialized, depending on the kind of initialization
1561 for the reference, and the reference is bound to that temporary. */
1564 skip:;
1565 }
1568 {
1573 else
1575 }
1581 else
1584 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1589 /* Same mask as real_lvalue_p. */
1596 /* Figure out whether or not the types are reference-related and
1597 reference compatible. We have to do this after stripping
1598 references from FROM. */
1600 /* If this is a C cast, first convert to an appropriately qualified
1601 type, so that we can later do a const_cast to the desired type. */
1607 /* Directly bind reference when target expression's type is compatible with
1608 the reference and expression is an lvalue. In DR391, the wording in
1609 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1610 const and rvalue references to rvalues of compatible class type.
1611 We should also do direct bindings for non-class xvalues. */
1613 {
1614 /* [dcl.init.ref]
1616 If the initializer expression
1618 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1619 is reference-compatible with "cv2 T2,"
1621 the reference is bound directly to the initializer expression
1622 lvalue.
1624 [...]
1625 If the initializer expression is an rvalue, with T2 a class type,
1626 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1627 is bound to the object represented by the rvalue or to a sub-object
1628 within that object. */
1634 /* Handle rvalue reference to function properly. */
1635 conv->rvaluedness_matches_p
1637 else
1638 conv->rvaluedness_matches_p
1643 /* For the purposes of overload resolution, we ignore the fact
1644 this expression is a bitfield or packed field. (In particular,
1645 [over.ics.ref] says specifically that a function with a
1646 non-const reference parameter is viable even if the
1647 argument is a bitfield.)
1649 However, when we actually call the function we must create
1650 a temporary to which to bind the reference. If the
1651 reference is volatile, or isn't const, then we cannot make
1652 a temporary, so we just issue an error when the conversion
1653 actually occurs. */
1656 /* Don't allow binding of lvalues (other than function lvalues) to
1657 rvalue references. */
1662 /* Nor the reverse. */
1673 }
1674 /* [class.conv.fct] A conversion function is never used to convert a
1675 (possibly cv-qualified) object to the (possibly cv-qualified) same
1676 object type (or a reference to it), to a (possibly cv-qualified) base
1677 class of that type (or a reference to it).... */
1680 {
1681 /* [dcl.init.ref]
1683 If the initializer expression
1685 -- has a class type (i.e., T2 is a class type) can be
1686 implicitly converted to an lvalue of type "cv3 T3," where
1687 "cv1 T1" is reference-compatible with "cv3 T3". (this
1688 conversion is selected by enumerating the applicable
1689 conversion functions (_over.match.ref_) and choosing the
1690 best one through overload resolution. (_over.match_).
1692 the reference is bound to the lvalue result of the conversion
1693 in the second case. */
1695 complain);
1698 }
1700 /* From this point on, we conceptually need temporaries, even if we
1701 elide them. Only the cases above are "direct bindings". */
1705 /* [over.ics.rank]
1707 When a parameter of reference type is not bound directly to an
1708 argument expression, the conversion sequence is the one required
1709 to convert the argument expression to the underlying type of the
1710 reference according to _over.best.ics_. Conceptually, this
1711 conversion sequence corresponds to copy-initializing a temporary
1712 of the underlying type with the argument expression. Any
1713 difference in top-level cv-qualification is subsumed by the
1714 initialization itself and does not constitute a conversion. */
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.
1722 We try below to treat this as a bad conversion to improve diagnostics,
1723 but if TO is an incomplete class, we need to reject this conversion
1724 now to avoid unnecessary instantiation. */
1729 /* We're generating a temporary now, but don't bind any more in the
1730 conversion (specifically, don't slice the temporary returned by a
1731 conversion operator). */
1734 /* Core issue 899: When [copy-]initializing a temporary to be bound
1735 to the first parameter of a copy constructor (12.8) called with
1736 a single argument in the context of direct-initialization,
1737 explicit conversion functions are also considered.
1739 So don't set LOOKUP_ONLYCONVERTING in that case. */
1750 {
1751 /* If initializing the temporary used a conversion function,
1752 recalculate the second conversion sequence. */
1756 {
1759 conversion *new_second
1765 }
1766 }
1769 /* This reference binding, unlike those above, requires the
1770 creation of a temporary. */
1774 /* [dcl.init.ref]
1776 Otherwise, the reference shall be an lvalue reference to a
1777 non-volatile const type, or the reference shall be an rvalue
1778 reference. */
1782 /* [dcl.init.ref]
1784 Otherwise, a temporary of type "cv1 T1" is created and
1785 initialized from the initializer expression using the rules for a
1786 non-reference copy initialization. If T1 is reference-related to
1787 T2, cv1 must be the same cv-qualification as, or greater
1788 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1793 }
1795 /* Returns the implicit conversion sequence (see [over.ics]) from type
1796 FROM to type TO. The optional expression EXPR may affect the
1797 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1798 true, this conversion is coming from a C-style cast. */
1803 {
1810 /* Other flags only apply to the primary function in overload
1811 resolution, or after we've chosen one. */
1816 /* FIXME: actually we don't want warnings either, but we can't just
1817 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1818 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1819 We really ought not to issue that warning until we've committed
1820 to that conversion. */
1823 /* Call reshape_init early to remove redundant braces. */
1828 {
1833 }
1837 else
1844 {
1848 /* As an extension, allow list-initialization of _Complex. */
1850 {
1854 }
1856 /* Allow conversion from an initializer-list with one element to a
1857 scalar type. */
1859 {
1861 tree elt;
1867 else
1873 {
1876 /* Too many levels of braces, i.e. '{{1}}'. */
1879 }
1880 }
1883 }
1889 {
1899 {
1903 {
1904 /* "If C is not an initializer-list constructor and the
1905 initializer list has a single element of type cv U, where U is
1906 X or a class derived from X, the implicit conversion sequence
1907 has Exact Match rank if U is X, or Conversion rank if U is
1908 derived from X." */
1914 }
1916 }
1918 /* We used to try to bind a reference to a temporary here, but that
1919 is now handled after the recursive call to this function at the end
1920 of reference_binding. */
1922 }
1925 }
1927 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1928 functions. ARGS will not be changed until a single candidate is
1929 selected. */
1938 {
1956 }
1958 /* Return the number of remaining arguments in the parameter list
1959 beginning with ARG. */
1961 int
1963 {
1968 n++;
1971 }
1973 /* Create an overload candidate for the function or method FN called
1974 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1975 FLAGS is passed on to implicit_conversion.
1977 This does not change ARGS.
1979 CTYPE, if non-NULL, is the type we want to pretend this function
1980 comes from for purposes of overload resolution. */
1987 tsubst_flags_t complain)
1988 {
1992 tree parmnode;
1998 /* At this point we should not see any functions which haven't been
1999 explicitly declared, except for friend functions which will have
2000 been found using argument dependent lookup. */
2003 /* The `this', `in_chrg' and VTT arguments to constructors are not
2004 considered in overload resolution. */
2006 {
2008 /* Bring back parameters omitted from an inherited ctor. */
2010 else
2014 {
2017 }
2018 }
2019 else
2025 /* 13.3.2 - Viable functions [over.match.viable]
2026 First, to be a viable function, a candidate function shall have enough
2027 parameters to agree in number with the arguments in the list.
2029 We need to check this first; otherwise, checking the ICSes might cause
2030 us to produce an ill-formed template instantiation. */
2034 {
2038 }
2042 {
2046 }
2048 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2049 parameter of type "reference to cv C" (including such a constructor
2050 instantiated from a template) is excluded from the set of candidate
2051 functions when used to construct an object of type D with an argument list
2052 containing a single argument if C is reference-related to D. */
2054 && flag_new_inheriting_ctors
2056 {
2062 {
2065 }
2066 }
2068 /* Second, for a function to be viable, its constraints must be
2069 satisfied. */
2072 {
2075 }
2077 /* When looking for a function from a subobject from an implicit
2078 copy/move constructor/operator=, don't consider anything that takes (a
2079 reference to) an unrelated type. See c++/44909 and core 1092. */
2081 {
2087 else
2090 {
2093 ctype))
2095 }
2097 /* This only applies at the top level. */
2099 }
2104 /* Third, for F to be a viable function, there shall exist for each
2105 argument an implicit conversion sequence that converts that argument
2106 to the corresponding parameter of F. */
2111 {
2113 tree arg;
2122 else
2131 {
2137 /* The type of the implicit object parameter ('this') for
2138 overload resolution is not always the same as for the
2139 function itself; conversion functions are considered to
2140 be members of the class being converted, and functions
2141 introduced by a using-declaration are considered to be
2142 members of the class that uses them.
2144 Since build_over_call ignores the ICS for the `this'
2145 parameter, we can just change the parm type. */
2147 {
2148 parmtype = cp_build_qualified_type
2151 {
2152 /* If the function has a ref-qualifier, the implicit
2153 object parameter has reference type. */
2156 /* The special handling of 'this' conversions in compare_ics
2157 does not apply if there is a ref-qualifier. */
2159 }
2160 else
2161 {
2165 }
2166 }
2168 /* Core issue 899: When [copy-]initializing a temporary to be bound
2169 to the first parameter of a copy constructor (12.8) called with
2170 a single argument in the context of direct-initialization,
2171 explicit conversion functions are also considered.
2173 So set LOOKUP_COPY_PARM to let reference_binding know that
2174 it's being called in that context. We generalize the above
2175 to handle move constructors and template constructors as well;
2176 the standardese should soon be updated similarly. */
2180 && (same_type_ignoring_top_level_qualifiers_p
2182 {
2185 /* We allow user-defined conversions within init-lists, but
2186 don't list-initialize the copy parm, as that would mean
2187 using two levels of braces for the same type. */
2191 }
2192 else
2198 }
2199 else
2200 {
2204 }
2211 {
2215 }
2218 {
2221 }
2222 }
2224 out:
2227 }
2229 /* Create an overload candidate for the conversion function FN which will
2230 be invoked for expression OBJ, producing a pointer-to-function which
2231 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2232 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2233 passed on to implicit_conversion.
2235 Actually, we don't really care about FN; we care about the type it
2236 converts to. There may be multiple conversion functions that will
2237 convert to that type, and we rely on build_user_type_conversion_1 to
2238 choose the best one; so when we create our candidate, we record the type
2239 instead of the function. */
2245 tsubst_flags_t complain)
2246 {
2264 /* Don't bother looking up the same type twice. */
2269 {
2275 else
2280 {
2283 /* Leave the 'cand' field null; we'll figure out the conversion in
2284 convert_like_real if this candidate is chosen. */
2286 }
2290 {
2294 }
2295 else
2296 {
2300 }
2307 {
2310 }
2317 }
2321 {
2325 }
2329 }
2331 static void
2335 {
2349 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2350 conversion ops are allowed. We handle that here by just checking for
2351 boolean_type_node because other operators don't ask for it. COND_EXPR
2352 also does contextual conversion to bool for the first operand, but we
2353 handle that in build_conditional_expr, and type1 here is operand 2. */
2358 {
2365 {
2367 /* We need something for printing the candidate. */
2371 }
2373 {
2377 }
2379 }
2381 /* For COND_EXPR we rearranged the arguments; undo that now. */
2383 {
2388 complain);
2391 else
2392 {
2395 boolean_type_node);
2396 }
2397 }
2404 }
2406 static bool
2408 {
2410 }
2412 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2414 static bool
2416 {
2417 /* [over.built]
2419 In this section, the term promoted integral type is used to refer
2420 to those integral types which are preserved by integral promotion
2421 (including e.g. int and long but excluding e.g. char).
2422 Similarly, the term promoted arithmetic type refers to promoted
2423 integral types plus floating types. */
2427 }
2429 /* Create any builtin operator overload candidates for the operator in
2430 question given the converted operand types TYPE1 and TYPE2. The other
2431 args are passed through from add_builtin_candidates to
2432 build_builtin_candidate.
2434 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2435 If CODE is requires candidates operands of the same type of the kind
2436 of which TYPE1 and TYPE2 are, we add both candidates
2437 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2439 static void
2443 tsubst_flags_t complain)
2444 {
2446 {
2454 }
2457 {
2459 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2460 and VQ is either volatile or empty, there exist candidate operator
2461 functions of the form
2462 VQ T& operator++(VQ T&);
2463 T operator++(VQ T&, int);
2464 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2465 type other than bool, and VQ is either volatile or empty, there exist
2466 candidate operator functions of the form
2467 VQ T& operator--(VQ T&);
2468 T operator--(VQ T&, int);
2469 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2470 complete object type, and VQ is either volatile or empty, there exist
2471 candidate operator functions of the form
2472 T*VQ& operator++(T*VQ&);
2473 T*VQ& operator--(T*VQ&);
2474 T* operator++(T*VQ&, int);
2475 T* operator--(T*VQ&, int); */
2481 /* FALLTHRU */
2485 {
2488 }
2491 /* 7 For every cv-qualified or cv-unqualified object type T, there
2492 exist candidate operator functions of the form
2494 T& operator*(T*);
2496 8 For every function type T, there exist candidate operator functions of
2497 the form
2498 T& operator*(T*); */
2507 /* 9 For every type T, there exist candidate operator functions of the form
2508 T* operator+(T*);
2510 10For every promoted arithmetic type T, there exist candidate operator
2511 functions of the form
2512 T operator+(T);
2513 T operator-(T); */
2518 /* FALLTHRU */
2524 /* 11For every promoted integral type T, there exist candidate operator
2525 functions of the form
2526 T operator~(T); */
2533 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2534 is the same type as C2 or is a derived class of C2, T is a complete
2535 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2536 there exist candidate operator functions of the form
2537 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2538 where CV12 is the union of CV1 and CV2. */
2542 {
2550 }
2553 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2554 didate operator functions of the form
2555 LR operator*(L, R);
2556 LR operator/(L, R);
2557 LR operator+(L, R);
2558 LR operator-(L, R);
2559 bool operator<(L, R);
2560 bool operator>(L, R);
2561 bool operator<=(L, R);
2562 bool operator>=(L, R);
2563 bool operator==(L, R);
2564 bool operator!=(L, R);
2565 where LR is the result of the usual arithmetic conversions between
2566 types L and R.
2568 14For every pair of types T and I, where T is a cv-qualified or cv-
2569 unqualified complete object type and I is a promoted integral type,
2570 there exist candidate operator functions of the form
2571 T* operator+(T*, I);
2572 T& operator[](T*, I);
2573 T* operator-(T*, I);
2574 T* operator+(I, T*);
2575 T& operator[](I, T*);
2577 15For every T, where T is a pointer to complete object type, there exist
2578 candidate operator functions of the form112)
2579 ptrdiff_t operator-(T, T);
2581 16For every pointer or enumeration type T, there exist candidate operator
2582 functions of the form
2583 bool operator<(T, T);
2584 bool operator>(T, T);
2585 bool operator<=(T, T);
2586 bool operator>=(T, T);
2587 bool operator==(T, T);
2588 bool operator!=(T, T);
2590 17For every pointer to member type T, there exist candidate operator
2591 functions of the form
2592 bool operator==(T, T);
2593 bool operator!=(T, T); */
2600 {
2603 }
2604 /* FALLTHRU */
2617 {
2620 }
2622 {
2625 }
2626 /* Fall through. */
2642 {
2645 }
2648 {
2651 }
2657 /* FALLTHRU */
2660 {
2663 }
2665 {
2668 }
2671 /* 18For every pair of promoted integral types L and R, there exist candi-
2672 date operator functions of the form
2673 LR operator%(L, R);
2674 LR operator&(L, R);
2675 LR operator^(L, R);
2676 LR operator|(L, R);
2677 L operator<<(L, R);
2678 L operator>>(L, R);
2679 where LR is the result of the usual arithmetic conversions between
2680 types L and R. */
2688 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2692 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2693 type, VQ is either volatile or empty, and R is a promoted arithmetic
2694 type, there exist candidate operator functions of the form
2695 VQ L& operator=(VQ L&, R);
2696 VQ L& operator*=(VQ L&, R);
2697 VQ L& operator/=(VQ L&, R);
2698 VQ L& operator+=(VQ L&, R);
2699 VQ L& operator-=(VQ L&, R);
2701 20For every pair T, VQ), where T is any type and VQ is either volatile
2702 or empty, there exist candidate operator functions of the form
2703 T*VQ& operator=(T*VQ&, T*);
2705 21For every pair T, VQ), where T is a pointer to member type and VQ is
2706 either volatile or empty, there exist candidate operator functions of
2707 the form
2708 VQ T& operator=(VQ T&, T);
2710 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2711 unqualified complete object type, VQ is either volatile or empty, and
2712 I is a promoted integral type, there exist candidate operator func-
2713 tions of the form
2714 T*VQ& operator+=(T*VQ&, I);
2715 T*VQ& operator-=(T*VQ&, I);
2717 23For every triple L, VQ, R), where L is an integral or enumeration
2718 type, VQ is either volatile or empty, and R is a promoted integral
2719 type, there exist candidate operator functions of the form
2721 VQ L& operator%=(VQ L&, R);
2722 VQ L& operator<<=(VQ L&, R);
2723 VQ L& operator>>=(VQ L&, R);
2724 VQ L& operator&=(VQ L&, R);
2725 VQ L& operator^=(VQ L&, R);
2726 VQ L& operator|=(VQ L&, R); */
2730 {
2734 {
2737 }
2738 /* FALLTHRU */
2751 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2764 {
2767 }
2772 }
2777 /* [over.built]
2779 For every pair of promoted arithmetic types L and R, there
2780 exist candidate operator functions of the form
2782 LR operator?(bool, L, R);
2784 where LR is the result of the usual arithmetic conversions
2785 between types L and R.
2787 For every type T, where T is a pointer or pointer-to-member
2788 type, there exist candidate operator functions of the form T
2789 operator?(bool, T, T); */
2793 /* That's OK. */
2796 /* Otherwise, the types should be pointers. */
2800 /* We don't check that the two types are the same; the logic
2801 below will actually create two candidates; one in which both
2802 parameter types are TYPE1, and one in which both parameter
2803 types are TYPE2. */
2814 }
2816 /* Make sure we don't create builtin candidates with dependent types. */
2820 {
2821 /* Try to recover if one of the types is non-dependent. But if
2822 there's only one type, there's nothing we can do. */
2825 /* And we lose if both are dependent. */
2828 /* Or if they have different forms. */
2836 }
2838 /* If we're dealing with two pointer types or two enumeral types,
2839 we need candidates for both of them. */
2848 {
2850 {
2852 error_mark_node,
2853 error_mark_node,
2854 CPO_CONVERSION,
2855 tf_none);
2857 {
2858 build_builtin_candidate
2862 }
2863 }
2865 build_builtin_candidate
2867 build_builtin_candidate
2870 }
2872 build_builtin_candidate
2874 }
2876 tree
2878 {
2884 }
2886 /* There are three conditions of builtin candidates:
2888 1) bool-taking candidates. These are the same regardless of the input.
2889 2) pointer-pair taking candidates. These are generated for each type
2890 one of the input types converts to.
2891 3) arithmetic candidates. According to the standard, we should generate
2892 all of these, but I'm trying not to...
2894 Here we generate a superset of the possible candidates for this particular
2895 case. That is a subset of the full set the standard defines, plus some
2896 other cases which the standard disallows. add_builtin_candidate will
2897 filter out the invalid set. */
2899 static void
2903 {
2907 /* TYPES[i] is the set of possible builtin-operator parameter types
2908 we will consider for the Ith argument. */
2913 {
2916 else
2918 }
2921 {
2922 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2923 and VQ is either volatile or empty, there exist candidate operator
2924 functions of the form
2925 VQ T& operator++(VQ T&); */
2935 /* 24There also exist candidate operator functions of the form
2936 bool operator!(bool);
2937 bool operator&&(bool, bool);
2938 bool operator||(bool, bool); */
2941 build_builtin_candidate
2948 build_builtin_candidate
2966 /* Fall through. */
2970 }
2976 {
2978 ;
2980 {
2981 tree convs;
2989 {
2994 }
3000 {
3013 {
3019 }
3023 }
3024 }
3025 else
3026 {
3031 {
3037 }
3039 }
3040 }
3042 /* Run through the possible parameter types of both arguments,
3043 creating candidates with those parameter types. */
3045 {
3047 tree u;
3051 add_builtin_candidate
3054 else
3055 add_builtin_candidate
3058 }
3062 }
3065 /* If TMPL can be successfully instantiated as indicated by
3066 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3068 TMPL is the template. EXPLICIT_TARGS are any explicit template
3069 arguments. ARGLIST is the arguments provided at the call-site.
3070 This does not change ARGLIST. The RETURN_TYPE is the desired type
3071 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3072 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3073 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3081 tsubst_flags_t complain)
3082 {
3092 tree arg;
3094 tree fn;
3098 /* We don't do deduction on the in-charge parameter, the VTT
3099 parameter or 'this'. */
3101 {
3105 /* We're deducing for a call to the result of a template conversion
3107 else
3109 }
3114 {
3117 else
3119 }
3127 {
3128 /* 12.8/6 says, "A declaration of a constructor for a class X is
3129 ill-formed if its first parameter is of type (optionally cv-qualified)
3130 X and either there are no other parameters or else all other
3131 parameters have default arguments. A member function template is never
3132 instantiated to produce such a constructor signature."
3134 So if we're trying to copy an object of the containing class, don't
3135 consider a template constructor that has a first parameter type that
3136 is just a template parameter, as we would deduce a signature that we
3137 would then reject in the code below. */
3139 {
3144 {
3148 }
3149 }
3150 }
3157 {
3160 }
3164 {
3167 }
3172 args_without_in_chrg,
3173 nargs_without_in_chrg,
3178 {
3179 /* Don't repeat unification later if it already resulted in errors. */
3183 nargs_without_in_chrg,
3185 else
3188 }
3191 {
3194 ctype))
3195 {
3196 /* We're trying to produce a constructor with a prohibited signature,
3197 as discussed above; handle here any cases we didn't catch then,
3198 such as X(X<T>). */
3201 }
3202 }
3205 /* Aha, this is a conversion function. */
3208 else
3213 /* This situation can occur if a member template of a template
3214 class is specialized. Then, instantiate_template might return
3215 an instantiation of the specialization, in which case the
3216 DECL_TI_TEMPLATE field will point at the original
3217 specialization. For example:
3219 template <class T> struct S { template <class U> void f(U);
3220 template <> void f(int) {}; };
3221 S<double> sd;
3222 sd.f(3);
3224 Here, TMPL will be template <class U> S<double>::f(U).
3225 And, instantiate template will give us the specialization
3226 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3227 for this will point at template <class T> template <> S<T>::f(int),
3228 so that we can find the definition. For the purposes of
3229 overload resolution, however, we want the original TMPL. */
3231 else
3236 fail:
3239 }
3248 {
3249 return
3254 }
3256 /* Create an overload candidate for the conversion function template TMPL,
3257 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3258 pointer-to-function which will in turn be called with the argument list
3259 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3260 passed on to implicit_conversion. */
3264 tree obj,
3268 {
3269 /* Making this work broke PR 71117, so until the committee resolves core
3270 issue 2189, let's disable this candidate if there are any viable call
3271 operators. */
3275 return
3279 complain);
3280 }
3282 /* The CANDS are the set of candidates that were considered for
3283 overload resolution. Return the set of viable candidates, or CANDS
3284 if none are viable. If any of the candidates were viable, set
3285 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3286 considered viable only if it is strictly viable. */
3292 {
3298 /* Be strict inside templates, since build_over_call won't actually
3299 do the conversions to get pedwarns. */
3309 {
3313 {
3314 /* Be strict in the presence of a viable candidate. Also if
3315 there are template candidates, so that we get deduction errors
3316 for them instead of silently preferring a bad conversion. */
3319 {
3320 /* Put any spliced near matches back onto the main list so
3321 that we see them if there is no strict match. */
3327 }
3328 }
3331 {
3339 }
3340 else
3342 }
3345 }
3347 static bool
3349 {
3354 }
3356 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3357 words, it is about to become the "this" pointer for a member
3358 function call. Take the address of the object. */
3360 static tree
3362 {
3363 /* In a template, we are only concerned about the type of the
3364 expression, so we can take a shortcut. */
3369 }
3371 /* Returns true iff functions are equivalent. Equivalent functions are
3372 not '==' only if one is a function-local extern function or if
3373 both are extern "C". */
3377 {
3386 }
3388 /* Print information about a candidate being rejected due to INFO. */
3390 static void
3392 {
3397 {
3398 /* Conversion of implicit `this' argument failed. */
3400 /* A bad conversion for 'this' must be discarding cv-quals. */
3403 from);
3404 else
3408 }
3410 {
3415 tf_warning_or_error);
3416 }
3418 /* Conversion of conversion function return value failed. */
3421 else
3424 }
3426 /* Print information about a candidate with WANT parameters and we found
3427 HAVE. */
3429 static void
3431 {
3436 }
3438 /* Print information about one overload candidate CANDIDATE. MSGSTR
3439 is the text to print before the candidate itself.
3441 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3442 to have been run through gettext by the caller. This wart makes
3443 life simpler in print_z_candidates and for the translators. */
3445 static void
3448 {
3458 {
3469 else
3472 }
3479 else
3482 {
3485 }
3486 /* Give the user some information about why this candidate failed. */
3488 {
3492 {
3505 "cannot be converted to %qT with a qualification "
3511 "conversion function specialization to %qT is not an "
3516 /* We use template_unification_error_rejection if unification caused
3517 actual non-SFINAE errors, in which case we don't need to repeat
3518 them here. */
3520 {
3524 }
3525 /* Re-run template unification with diagnostics. */
3529 (make_tree_vec
3540 " a constructor taking a single argument of its own "
3544 {
3548 }
3552 "initialization from an expression of the same or derived "
3557 /* This candidate didn't have any issues or we failed to
3558 handle a particular code. Either way... */
3560 }
3561 }
3562 }
3564 static void
3566 {
3573 /* Remove non-viable deleted candidates. */
3576 {
3581 else
3583 }
3584 /* ...if there are any non-deleted ones. */
3588 /* There may be duplicates in the set of candidates. We put off
3589 checking this condition as long as possible, since we have no way
3590 to eliminate duplicates from a set of functions in less than n^2
3591 time. Now we are about to emit an error message, so it is more
3592 permissible to go slowly. */
3594 {
3596 /* Skip builtin candidates and conversion functions. */
3601 {
3605 else
3607 }
3608 }
3612 }
3614 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3615 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3616 the result of the conversion function to convert it to the final
3617 desired type. Merge the two sequences into a single sequence,
3618 and return the merged sequence. */
3622 {
3628 /* Find the end of the second conversion sequence. */
3630 {
3631 /* The entire sequence is a user-conversion sequence. */
3635 }
3637 /* Replace the identity conversion with the user conversion
3638 sequence. */
3642 }
3644 /* Handle overload resolution for initializing an object of class type from
3645 an initializer list. First we look for a suitable constructor that
3646 takes a std::initializer_list; if we don't find one, we then look for a
3647 non-list constructor.
3649 Parameters are as for add_candidates, except that the arguments are in
3650 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3651 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3653 static void
3660 tsubst_flags_t complain)
3661 {
3664 /* We're looking for a ctor for list-initialization. */
3666 /* And we don't allow narrowing conversions. We also use this flag to
3667 avoid the copy constructor call for copy-list-initialization. */
3673 /* Always use the default constructor if the list is empty (DR 990). */
3676 ;
3677 /* If the class has a list ctor, try passing the list as a single
3678 argument first, but only consider list ctors. */
3680 {
3687 }
3689 /* Expand the CONSTRUCTOR into a new argument vec. */
3697 /* We aren't looking for list-ctors anymore. */
3699 /* We allow more user-defined conversions within an init-list. */
3705 }
3707 /* Returns the best overload candidate to perform the requested
3708 conversion. This function is used for three the overloading situations
3709 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3710 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3711 per [dcl.init.ref], so we ignore temporary bindings. */
3715 tsubst_flags_t complain)
3716 {
3718 tree fromtype;
3732 /* We represent conversion within a hierarchy using RVALUE_CONV and
3733 BASE_CONV, as specified by [over.best.ics]; these become plain
3734 constructor calls, as specified in [dcl.init]. */
3739 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3740 creating a garbage BASELINK; constructors can't be inherited. */
3743 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3744 a single element. For now, let's handle constructors as before and also
3745 consider conversion operators from the element. */
3752 {
3757 {
3758 /* [class.conv.fct] A conversion function is never used to
3759 convert a (possibly cv-qualified) object to the (possibly
3760 cv-qualified) same object type (or a reference to it), to a
3761 (possibly cv-qualified) base class of that type (or a
3762 reference to it)... */
3763 }
3764 else
3766 }
3773 /* It's OK to bind a temporary for converting constructor arguments, but
3774 not in converting the return value of a conversion operator. */
3780 {
3785 /* We should never try to call the abstract or base constructor
3786 from here. */
3792 {
3793 /* List-initialization. */
3797 }
3798 else
3799 {
3803 }
3806 {
3809 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3810 set, then this is copy-initialization. In that case, "The
3811 result of the call is then used to direct-initialize the
3812 object that is the destination of the copy-initialization."
3813 [dcl.init]
3815 We represent this in the conversion sequence with an
3816 rvalue conversion, which means a constructor call. */
3819 cand->second_conv
3821 }
3822 }
3825 {
3827 /* FIXME see above about C++17. */
3829 else
3831 }
3834 {
3838 /* If we are called to convert to a reference type, we are trying to
3839 find a direct binding, so don't even consider temporaries. If
3840 we don't find a direct binding, the caller will try again to
3841 look for a temporary binding. */
3852 {
3854 conversion *ics
3856 rettype,
3859 complain);
3861 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3862 copy-initialization. In that case, "The result of the
3863 call is then used to direct-initialize the object that is
3864 the destination of the copy-initialization." [dcl.init]
3866 We represent this in the conversion sequence with an
3867 rvalue conversion, which means a constructor call. But
3868 don't add a second rvalue conversion if there's already
3869 one there. Which there really shouldn't be, but it's
3870 harmless since we'd add it here anyway. */
3878 {
3882 }
3885 {
3886 /* 13.3.1.5: For direct-initialization, those explicit
3887 conversion functions that are not hidden within S and
3888 yield type T or a type that can be converted to type T
3889 with a qualification conversion (4.4) are also candidate
3890 functions. */
3891 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3892 I've raised this issue with the committee. --jason 9/2011 */
3895 }
3897 {
3899 cand->reason
3902 }
3905 {
3906 /* 13.3.3.1.2: If the user-defined conversion is specified by
3907 a specialization of a conversion function template, the
3908 second standard conversion sequence shall have exact match
3909 rank. */
3912 }
3913 }
3914 }
3918 {
3922 }
3926 {
3928 {
3932 }
3939 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3940 ambiguous conversion is no worse than another user-defined
3941 conversion. */
3944 }
3946 tree convtype;
3950 /* DR 5: [in the first step of copy-initialization]...if the function
3951 is a constructor, the call initializes a temporary of the
3952 cv-unqualified version of the destination type. */
3954 else
3956 /* Build the user conversion sequence. */
3957 conv = build_conv
3959 convtype,
3965 /* Remember that this was a list-initialization. */
3969 /* Combine it with the second conversion sequence. */
3974 }
3976 /* Wrapper for above. */
3978 tree
3980 tsubst_flags_t complain)
3981 {
3983 tree ret;
3989 {
3992 else
3993 {
3996 }
3997 }
3998 else
4003 }
4005 /* Subroutine of convert_nontype_argument.
4007 EXPR is an expression used in a context that requires a converted
4008 constant-expression, such as a template non-type parameter. Do any
4009 necessary conversions (that are permitted for converted
4010 constant-expressions) to convert it to the desired type.
4012 If conversion is successful, returns the converted expression;
4013 otherwise, returns error_mark_node. */
4015 tree
4017 {
4020 tree t;
4026 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4033 /* A converted constant expression of type T is an expression, implicitly
4034 converted to type T, where the converted expression is a constant
4035 expression and the implicit conversion sequence contains only
4037 * user-defined conversions,
4038 * lvalue-to-rvalue conversions (7.1),
4039 * array-to-pointer conversions (7.2),
4040 * function-to-pointer conversions (7.3),
4041 * qualification conversions (7.5),
4042 * integral promotions (7.6),
4043 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4044 * null pointer conversions (7.11) from std::nullptr_t,
4045 * null member pointer conversions (7.12) from std::nullptr_t, and
4046 * function pointer conversions (7.13),
4048 and where the reference binding (if any) binds directly. */
4053 {
4055 {
4056 /* A conversion function is OK. If it isn't constexpr, we'll
4057 complain later that the argument isn't constant. */
4059 /* The lvalue-to-rvalue conversion is OK. */
4061 /* Array-to-pointer and function-to-pointer. */
4063 /* Function pointer conversions. */
4065 /* Qualification conversions. */
4071 {
4077 }
4087 /* Integral promotion or conversion. */
4090 /* Conversion from nullptr to pointer or pointer-to-member. */
4096 /* fall through. */
4101 }
4102 }
4104 /* Avoid confusing convert_nontype_argument by introducing
4105 a redundant conversion to the same reference type. */
4108 {
4112 }
4116 else
4119 /* Free all the conversions we allocated. */
4123 }
4125 /* Do any initial processing on the arguments to a function call. */
4129 {
4131 tree arg;
4134 {
4138 {
4142 }
4145 }
4147 }
4149 /* Perform overload resolution on FN, which is called with the ARGS.
4151 Return the candidate function selected by overload resolution, or
4152 NULL if the event that overload resolution failed. In the case
4153 that overload resolution fails, *CANDIDATES will be the set of
4154 candidates considered, and ANY_VIABLE_P will be set to true or
4155 false to indicate whether or not any of the candidates were
4156 viable.
4158 The ARGS should already have gone through RESOLVE_ARGS before this
4159 function is called. */
4166 {
4168 tree explicit_targs;
4179 /* Check FN. */
4186 {
4190 }
4192 /* Add the various candidate functions. */
4197 LOOKUP_NORMAL,
4203 else
4208 }
4210 /* Print an error message about being unable to build a call to FN with
4211 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4212 be located; CANDIDATES is a possibly empty list of such
4213 functions. */
4215 static void
4218 {
4221 {
4224 }
4233 else
4238 }
4240 /* Return an expression for a call to FN (a namespace-scope function,
4241 or a static member function) with the ARGS. This may change
4242 ARGS. */
4244 tree
4246 tsubst_flags_t complain)
4247 {
4251 tree result;
4254 {
4258 }
4263 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4267 complain);
4270 {
4272 {
4273 // If there is a single (non-viable) function candidate,
4274 // let the error be diagnosed by cp_build_function_call_vec.
4279 // Otherwise, emit notes for non-viable candidates.
4281 }
4283 }
4284 else
4285 {
4287 /* If fn is template_id_expr, the call has explicit template arguments
4288 (e.g. func<int>(5)), communicate this info to build_over_call
4289 through flags so that later we can use it to decide whether to warn
4290 about peculiar null pointer conversion. */
4292 {
4293 /* If overload resolution selects a specialization of a
4294 function concept for non-dependent template arguments,
4295 the expression is true if the constraints are satisfied
4296 and false otherwise.
4298 NOTE: This is an extension of Concepts Lite TS that
4299 allows constraints to be used in expressions. */
4301 {
4307 }
4310 }
4313 }
4315 /* Free all the conversions we allocated. */
4319 }
4321 /* Build a call to a global operator new. FNNAME is the name of the
4322 operator (either "operator new" or "operator new[]") and ARGS are
4323 the arguments provided. This may change ARGS. *SIZE points to the
4324 total number of bytes required by the allocation, and is updated if
4325 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4326 be used. If this function determines that no cookie should be
4327 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4328 is not NULL_TREE, it is evaluated before calculating the final
4329 array size, and if it fails, the array size is replaced with
4330 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4331 is non-NULL, it will be set, upon return, to the allocation
4332 function called. */
4334 tree
4339 {
4341 tree fns;
4348 /* Set to (size_t)-1 if the size check fails. */
4350 {
4356 }
4362 /* Based on:
4364 [expr.new]
4366 If this lookup fails to find the name, or if the allocated type
4367 is not a class type, the allocation function's name is looked
4368 up in the global scope.
4370 we disregard block-scope declarations of "operator new". */
4375 {
4380 /* If no aligned allocation function matches, try again without the
4381 alignment. */
4382 }
4384 /* Figure out what function is being called. */
4387 complain);
4389 /* If no suitable function could be found, issue an error message
4390 and give up. */
4392 {
4396 }
4398 /* If a cookie is required, add some extra space. Whether
4399 or not a cookie is required cannot be determined until
4400 after we know which function was called. */
4402 {
4404 tree arg_types;
4407 /* Skip the size_t parameter. */
4409 /* Check the remaining parameters (if any). */
4413 ptr_type_node))
4415 /* If we need a cookie, adjust the number of bytes allocated. */
4417 {
4418 /* Update the total size. */
4421 {
4422 /* Set to (size_t)-1 if the size check fails. */
4426 }
4427 /* Update the argument list to reflect the adjusted size. */
4429 }
4430 else
4432 }
4434 /* Tell our caller which function we decided to call. */
4438 /* Build the CALL_EXPR. */
4440 }
4442 /* Build a new call to operator(). This may change ARGS. */
4444 static tree
4446 {
4460 {
4462 /* It's no good looking for an overloaded operator() on a
4463 pointer-to-member-function. */
4467 }
4470 {
4474 }
4475 else
4479 {
4483 }
4485 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4489 {
4497 }
4502 {
4510 {
4517 add_template_conv_candidate
4521 else
4525 }
4526 }
4528 /* Be strict here because if we choose a bad conversion candidate, the
4529 errors we get won't mention the call context. */
4532 {
4534 {
4538 }
4540 }
4541 else
4542 {
4545 {
4547 {
4551 }
4553 }
4554 /* Since cand->fn will be a type, not a function, for a conversion
4555 function, we must be careful not to unconditionally look at
4556 DECL_NAME here. */
4560 else
4561 {
4565 else
4569 }
4570 }
4572 /* Free all the conversions we allocated. */
4576 }
4578 /* Wrapper for above. */
4580 tree
4582 {
4583 tree ret;
4588 }
4590 /* Called by op_error to prepare format strings suitable for the error
4591 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4592 and a suffix (controlled by NTYPES). */
4596 {
4606 else
4610 }
4612 static void
4615 {
4620 else
4624 {
4630 else
4642 else
4652 else
4663 else
4673 else
4678 else
4682 else
4687 }
4688 }
4690 /* Return the implicit conversion sequence that could be used to
4691 convert E1 to E2 in [expr.cond]. */
4695 {
4701 /* [expr.cond]
4703 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4704 implicitly converted (clause _conv_) to the type "lvalue reference to
4705 T2", subject to the constraint that in the conversion the
4706 reference must bind directly (_dcl.init.ref_) to an lvalue.
4708 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4709 implicitly converted to the type "rvalue reference to T2", subject to
4710 the constraint that the reference must bind directly. */
4712 {
4715 t1,
4716 e1,
4718 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4720 complain);
4723 }
4725 /* If E2 is a prvalue or if neither of the conversions above can be done
4726 and at least one of the operands has (possibly cv-qualified) class
4727 type: */
4731 /* [expr.cond]
4733 If E1 and E2 have class type, and the underlying class types are
4734 the same or one is a base class of the other: E1 can be converted
4735 to match E2 if the class of T2 is the same type as, or a base
4736 class of, the class of T1, and the cv-qualification of T2 is the
4737 same cv-qualification as, or a greater cv-qualification than, the
4738 cv-qualification of T1. If the conversion is applied, E1 is
4739 changed to an rvalue of type T2 that still refers to the original
4740 source class object (or the appropriate subobject thereof). */
4743 {
4745 {
4750 else
4753 }
4754 else
4756 }
4757 else
4758 /* [expr.cond]
4760 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4761 converted to the type that expression E2 would have if E2 were
4762 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4765 }
4767 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4768 arguments to the conditional expression. */
4770 static tree
4772 tsubst_flags_t complain)
4773 {
4774 tree arg2_type;
4775 tree arg3_type;
4784 /* As a G++ extension, the second argument to the conditional can be
4785 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4786 c'.) If the second operand is omitted, make sure it is
4787 calculated only once. */
4789 {
4797 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4800 else
4802 }
4804 /* If something has already gone wrong, just pass that fact up the
4805 tree. */
4815 {
4818 /* If arg1 is another cond_expr choosing between -1 and 0,
4819 then we can use its comparison. It may help to avoid
4820 additional comparison, produce more accurate diagnostics
4821 and enables folding. */
4831 /* force_rvalue can return error_mark on valid arguments. */
4842 {
4843 /* Rely on the error messages of the scalar version. */
4852 {
4860 }
4864 /* We could pass complain & tf_warning to unsafe_conversion_p,
4865 but the warnings (like Wsign-conversion) have already been
4866 given by the scalar build_conditional_expr_1. We still check
4867 unsafe_conversion_p to forbid truncating long long -> float. */
4869 {
4874 }
4876 {
4881 }
4891 }
4894 {
4900 {
4904 {
4910 }
4912 {
4918 }
4921 }
4922 }
4928 {
4931 "incompatible vector types in conditional expression: "
4935 }
4938 {
4941 }
4943 }
4945 /* [expr.cond]
4947 The first expression is implicitly converted to bool (clause
4948 _conv_). */
4950 LOOKUP_NORMAL);
4954 /* [expr.cond]
4956 If either the second or the third operand has type (possibly
4957 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4958 array-to-pointer (_conv.array_), and function-to-pointer
4959 (_conv.func_) standard conversions are performed on the second
4960 and third operands. */
4964 {
4965 /* Do the conversions. We don't these for `void' type arguments
4966 since it can't have any effect and since decay_conversion
4967 does not handle that case gracefully. */
4975 /* [expr.cond]
4977 One of the following shall hold:
4979 --The second or the third operand (but not both) is a
4980 throw-expression (_except.throw_); the result is of the
4981 type of the other and is an rvalue.
4983 --Both the second and the third operands have type void; the
4984 result is of type void and is an rvalue.
4986 We must avoid calling force_rvalue for expressions of type
4987 "void" because it will complain that their value is being
4988 used. */
4991 {
4993 {
4997 }
5000 }
5003 {
5005 {
5009 }
5012 }
5015 else
5016 {
5018 {
5021 "second operand to the conditional operator "
5022 "is of type %<void%>, but the third operand is "
5024 else
5026 "third operand to the conditional operator "
5027 "is of type %<void%>, but the second operand is "
5029 }
5031 }
5035 }
5036 /* [expr.cond]
5038 Otherwise, if the second and third operand have different types,
5039 and either has (possibly cv-qualified) class type, or if both are
5040 glvalues of the same value category and the same type except for
5041 cv-qualification, an attempt is made to convert each of those operands
5042 to the type of the other. */
5046 arg3_type)
5049 {
5054 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5060 /* [expr.cond]
5062 If both can be converted, or one can be converted but the
5063 conversion is ambiguous, the program is ill-formed. If
5064 neither can be converted, the operands are left unchanged and
5065 further checking is performed as described below. If exactly
5066 one conversion is possible, that conversion is applied to the
5067 chosen operand and the converted operand is used in place of
5068 the original operand for the remainder of this section. */
5073 {
5075 {
5082 else
5084 }
5086 }
5088 {
5092 /* Even if CONV2 is a valid conversion, the result of the
5093 conversion may be invalid. For example, if ARG3 has type
5094 "volatile X", and X does not have a copy constructor
5095 accepting a "volatile X&", then even if ARG2 can be
5096 converted to X, the conversion will fail. */
5100 }
5102 {
5109 }
5111 /* Free all the conversions we allocated. */
5117 /* If, after the conversion, both operands have class type,
5118 treat the cv-qualification of both operands as if it were the
5119 union of the cv-qualification of the operands.
5121 The standard is not clear about what to do in this
5122 circumstance. For example, if the first operand has type
5123 "const X" and the second operand has a user-defined
5124 conversion to "volatile X", what is the type of the second
5125 operand after this step? Making it be "const X" (matching
5126 the first operand) seems wrong, as that discards the
5127 qualification without actually performing a copy. Leaving it
5128 as "volatile X" seems wrong as that will result in the
5129 conditional expression failing altogether, even though,
5130 according to this step, the one operand could be converted to
5131 the type of the other. */
5139 }
5141 /* [expr.cond]
5143 If the second and third operands are glvalues of the same value
5144 category and have the same type, the result is of that type and
5145 value category. */
5149 {
5154 }
5156 /* [expr.cond]
5158 Otherwise, the result is an rvalue. If the second and third
5159 operand do not have the same type, and either has (possibly
5160 cv-qualified) class type, overload resolution is used to
5161 determine the conversions (if any) to be applied to the operands
5162 (_over.match.oper_, _over.built_). */
5166 {
5171 /* Rearrange the arguments so that add_builtin_candidate only has
5172 to know about two args. In build_builtin_candidate, the
5173 arguments are unscrambled. */
5178 COND_EXPR,
5179 NOP_EXPR,
5181 args,
5184 /* [expr.cond]
5186 If the overload resolution fails, the program is
5187 ill-formed. */
5190 {
5195 }
5198 {
5200 {
5203 }
5205 }
5207 /* [expr.cond]
5209 Otherwise, the conversions thus determined are applied, and
5210 the converted operands are used in place of the original
5211 operands for the remainder of this section. */
5220 }
5222 /* [expr.cond]
5224 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5225 and function-to-pointer (_conv.func_) standard conversions are
5226 performed on the second and third operands.
5228 We need to force the lvalue-to-rvalue conversion here for class types,
5229 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5230 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5231 regions. */
5244 /* [expr.cond]
5246 After those conversions, one of the following shall hold:
5248 --The second and third operands have the same type; the result is of
5249 that type. */
5252 /* [expr.cond]
5254 --The second and third operands have arithmetic or enumeration
5255 type; the usual arithmetic conversions are performed to bring
5256 them to a common type, and the result is of that type. */
5261 {
5262 /* In this case, there is always a common type. */
5264 arg3_type);
5267 "implicit conversion from %qH to %qI to "
5269 loc);
5273 {
5277 /* Two enumerators from the same enumeration can have different
5283 }
5290 {
5294 }
5298 }
5299 /* [expr.cond]
5301 --The second and third operands have pointer type, or one has
5302 pointer type and the other is a null pointer constant; pointer
5303 conversions (_conv.ptr_) and qualification conversions
5304 (_conv.qual_) are performed to bring them to their composite
5305 pointer type (_expr.rel_). The result is of the composite
5306 pointer type.
5308 --The second and third operands have pointer to member type, or
5309 one has pointer to member type and the other is a null pointer
5310 constant; pointer to member conversions (_conv.mem_) and
5311 qualification conversions (_conv.qual_) are performed to bring
5312 them to a common type, whose cv-qualification shall match the
5313 cv-qualification of either the second or the third operand.
5314 The result is of the common type. */
5322 {
5325 complain);
5330 }
5333 {
5338 }
5343 valid_operands:
5346 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5347 warn here, because the COND_EXPR will be turned into ARG2. */
5353 /* We can't use result_type below, as fold might have returned a
5354 throw_expr. */
5357 {
5358 /* Expand both sides into the same slot, hopefully the target of
5359 the ?: expression. We used to check for TARGET_EXPRs here,
5360 but now we sometimes wrap them in NOP_EXPRs so the test would
5361 fail. */
5364 /* If this expression is an rvalue, but might be mistaken for an
5365 lvalue, we must add a NON_LVALUE_EXPR. */
5367 }
5368 else
5372 }
5374 /* Wrapper for above. */
5376 tree
5378 tsubst_flags_t complain)
5379 {
5380 tree ret;
5385 }
5387 /* OPERAND is an operand to an expression. Perform necessary steps
5388 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5389 returned. */
5391 static tree
5393 {
5395 {
5398 /* Make sure the template type is instantiated now. */
5400 }
5403 }
5405 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5406 OVERLOAD) to the CANDIDATES, returning an updated list of
5407 CANDIDATES. The ARGS are the arguments provided to the call;
5408 if FIRST_ARG is non-null it is the implicit object argument,
5409 otherwise the first element of ARGS is used if needed. The
5410 EXPLICIT_TARGS are explicit template arguments provided.
5411 TEMPLATE_ONLY is true if only template functions should be
5412 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5413 add_function_candidate. */
5415 static void
5417 tree return_type,
5422 tsubst_flags_t complain)
5423 {
5424 tree ctype;
5428 unification_kind_t strict;
5433 /* Precalculate special handling of constructors and conversion ops. */
5436 {
5440 /* We're doing return_type(x). */
5442 else
5443 /* We're doing x.operator return_type(). */
5445 /* [over.match.funcs] For conversion functions, the function
5446 is considered to be a member of the class of the implicit
5447 object argument for the purpose of defining the type of
5448 the implicit object parameter. */
5450 }
5451 else
5452 {
5454 {
5456 /* For list-initialization we consider explicit constructors
5457 and complain if one is chosen. */
5458 check_converting
5461 }
5464 }
5468 else
5469 /* Delay creating the implicit this parameter until it is needed. */
5473 {
5485 {
5486 /* Figure out where the object arg comes from. If this
5487 function is a non-static member and we didn't get an
5488 implicit object argument, move it out of args. */
5490 {
5492 tree arg;
5499 }
5503 }
5507 fn,
5508 ctype,
5509 explicit_targs,
5510 fn_first_arg,
5511 fn_args,
5512 return_type,
5513 access_path,
5514 conversion_path,
5515 flags,
5516 strict,
5517 complain);
5520 fn,
5521 ctype,
5522 fn_first_arg,
5523 fn_args,
5524 access_path,
5525 conversion_path,
5526 flags,
5527 complain);
5528 }
5529 }
5531 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5532 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5534 static int
5536 {
5538 {
5539 // 5. b @= a
5543 // 6. a[b]
5547 // 1. a.b
5548 // Not overloadable (yet).
5549 // 2. a->b
5550 // Only one argument.
5551 // 3. a->*b
5553 // 7. a << b
5555 // 8. a >> b
5561 }
5562 }
5564 static tree
5567 {
5570 tree fnname;
5588 {
5592 }
5593 else
5600 {
5605 /* Use build_op_new_call and build_op_delete_call instead. */
5609 /* Use build_op_call instead. */
5616 /* These are saved for the sake of warn_logical_operator. */
5626 /* These are saved for the sake of maybe_warn_bool_compare. */
5631 /* =, ->, [], () must be non-static member functions. */
5635 /* FALLTHRU */
5643 }
5649 /* Use build_conditional_expr instead. */
5665 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5668 /* Add namespace-scope operators to the list of functions to
5669 consider. */
5671 {
5677 }
5683 /* Add class-member operators to the candidate set. */
5685 {
5686 tree fns;
5690 {
5693 }
5701 }
5702 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5703 only non-member functions that have type T1 or reference to
5704 cv-qualified-opt T1 for the first argument, if the first argument
5705 has an enumeration type, or T2 or reference to cv-qualified-opt
5706 T2 for the second argument, if the second argument has an
5707 enumeration type. Filter out those that don't match. */
5709 {
5713 {
5723 {
5729 && (same_type_ignoring_top_level_qualifiers_p
5734 }
5736 /* No argument has an appropriate type, so remove this
5737 candidate function from the list. */
5739 {
5742 }
5743 }
5744 }
5750 {
5753 /* For these, the built-in candidates set is empty
5754 [over.match.oper]/3. We don't want non-strict matches
5755 because exact matches are always possible with built-in
5756 operators. The built-in candidate set for COMPONENT_REF
5757 would be empty too, but since there are no such built-in
5758 operators, we accept non-strict matches for them. */
5765 }
5769 {
5771 {
5774 /* Don't try anything fancy if we're not allowed to produce
5775 errors. */
5779 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5780 distinguish between prefix and postfix ++ and
5781 operator++() was used for both, so we allow this with
5782 -fpermissive. */
5783 else
5784 {
5790 }
5797 else
5803 /* The caller will deal with these. */
5813 {
5814 /* If one of the arguments of the operator represents
5815 an invalid use of member function pointer, try to report
5816 a meaningful error ... */
5821 else
5822 {
5823 /* ... Otherwise, report the more generic
5824 "no matching operator found" error */
5827 }
5828 }
5831 }
5832 }
5833 else
5834 {
5837 {
5839 {
5842 }
5844 }
5846 {
5852 else
5858 {
5863 /* This prevents build_new_function_call from discarding this
5864 function during instantiation of the enclosing template. */
5867 /* Specify evaluation order as per P0145R2. */
5870 {
5881 }
5882 }
5883 }
5884 else
5885 {
5886 /* Give any warnings we noticed during overload resolution. */
5888 {
5892 }
5894 /* Check for comparison of different enum types. */
5896 {
5908 {
5912 }
5916 }
5918 /* We need to strip any leading REF_BIND so that bitfields
5919 don't cause errors. This should not remove any important
5920 conversions, because builtins don't apply to class
5921 objects directly. */
5928 {
5932 else
5935 /* We need to call warn_logical_operator before
5936 converting arg2 to a boolean_type, but after
5937 decaying an enumerator to its value. */
5944 }
5946 {
5951 }
5953 }
5954 }
5956 user_defined_result_ready:
5958 /* Free all the conversions we allocated. */
5964 builtin:
5966 {
5981 /* Fall through. */
5994 /* Fall through. */
6027 complain),
6030 /* The caller will deal with these. */
6038 }
6040 }
6042 /* Wrapper for above. */
6044 tree
6048 {
6049 tree ret;
6055 }
6057 /* CALL was returned by some call-building function; extract the actual
6058 CALL_EXPR from any bits that have been tacked on, e.g. by
6059 convert_from_reference. */
6061 tree
6063 {
6074 }
6076 /* Returns true if FN has two parameters, of which the second has type
6077 size_t. */
6079 static bool
6081 {
6093 }
6095 /* True if T, an allocation function, has std::align_val_t as its second
6096 argument. */
6098 bool
6100 {
6106 }
6108 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6109 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6110 std::align_val_t. */
6112 static bool
6114 {
6118 /* A template instance is never a usual deallocation function,
6119 regardless of its signature. */
6135 }
6137 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6138 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6140 bool
6142 {
6143 /* A template instance is never a usual deallocation function,
6144 regardless of its signature. */
6149 /* If a class T has a member deallocation function named operator delete
6150 with exactly one parameter, then that function is a usual
6151 (non-placement) deallocation function. If class T does not declare
6152 such an operator delete but does declare a member deallocation
6153 function named operator delete with exactly two parameters, the second
6154 of which has type std::size_t (18.2), then this function is a usual
6155 deallocation function. */
6167 }
6169 /* Build a call to operator delete. This has to be handled very specially,
6170 because the restrictions on what signatures match are different from all
6171 other call instances. For a normal delete, only a delete taking (void *)
6172 or (void *, size_t) is accepted. For a placement delete, only an exact
6173 match with the placement new is accepted.
6175 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6176 ADDR is the pointer to be deleted.
6177 SIZE is the size of the memory block to be deleted.
6178 GLOBAL_P is true if the delete-expression should not consider
6179 class-specific delete operators.
6180 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6182 If this call to "operator delete" is being generated as part to
6183 deallocate memory allocated via a new-expression (as per [expr.new]
6184 which requires that if the initialization throws an exception then
6185 we call a deallocation function), then ALLOC_FN is the allocation
6186 function. */
6188 tree
6192 {
6206 /* In [class.free]
6208 If the result of the lookup is ambiguous or inaccessible, or if
6209 the lookup selects a placement deallocation function, the
6210 program is ill-formed.
6212 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6213 {
6217 }
6218 else
6224 /* Strip const and volatile from addr. */
6228 {
6229 /* "A declaration of a placement deallocation function matches the
6230 declaration of a placement allocation function if it has the same
6231 number of parameters and, after parameter transformations (8.3.5),
6232 all parameter types except the first are identical."
6234 So we build up the function type we want and ask instantiate_type
6235 to get it for us. */
6246 /* "If the lookup finds the two-parameter form of a usual deallocation
6247 function (3.7.4.2) and that function, considered as a placement
6248 deallocation function, would have been selected as a match for the
6249 allocation function, the program is ill-formed." */
6251 {
6259 /* But if the class has an operator delete (void *), then that is
6260 the usual deallocation function, so we shouldn't complain
6261 about using the operator delete (void *, size_t). */
6265 {
6270 }
6271 /* Before C++14 a two-parameter global deallocation function is
6272 always a placement deallocation function, but warn if
6273 -Wc++14-compat. */
6275 {
6280 }
6283 {
6285 {
6286 /* Only mention C++14 for namespace-scope delete. */
6289 else
6291 "%qD is a usual (non-placement) deallocation "
6293 }
6294 }
6295 else
6297 ok:;
6298 }
6299 }
6300 else
6301 /* "Any non-placement deallocation function matches a non-placement
6302 allocation function. If the lookup finds a single matching
6303 deallocation function, that function will be called; otherwise, no
6304 deallocation function will be called." */
6306 {
6309 {
6311 {
6314 }
6316 /* -- If the type has new-extended alignment, a function with a
6317 parameter of type std::align_val_t is preferred; otherwise a
6318 function without such a parameter is preferred. If exactly one
6319 preferred function is found, that function is selected and the
6320 selection process terminates. If more than one preferred
6321 function is found, all non-preferred functions are eliminated
6322 from further consideration. */
6324 {
6330 {
6334 }
6335 }
6337 /* -- If the deallocation functions have class scope, the one
6338 without a parameter of type std::size_t is selected. */
6343 /* -- If the type is complete and if, for the second alternative
6344 (delete array) only, the operand is a pointer to a class type
6345 with a non-trivial destructor or a (possibly multi-dimensional)
6346 array thereof, the function with a parameter of type std::size_t
6347 is selected.
6349 -- Otherwise, it is unspecified whether a deallocation function
6350 with a parameter of type std::size_t is selected. */
6351 else
6352 {
6356 /* We need a cookie to determine the array size. */
6358 }
6364 }
6365 }
6367 /* If we have a matching function, call it. */
6369 {
6372 /* If the FN is a member function, make sure that it is
6373 accessible. */
6376 complain);
6378 /* Core issue 901: It's ok to new a type with deleted delete. */
6383 {
6384 /* The placement args might not be suitable for overload
6385 resolution at this point, so build the call directly. */
6395 }
6396 else
6397 {
6398 tree ret;
6404 {
6407 }
6411 }
6412 }
6414 /* [expr.new]
6416 If no unambiguous matching deallocation function can be found,
6417 propagating the exception does not cause the object's memory to
6418 be freed. */
6420 {
6424 alloc_fn);
6426 }
6432 }
6434 /* If the current scope isn't allowed to access DECL along
6435 BASETYPE_PATH, give an error. The most derived class in
6436 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6437 the declaration to use in the error diagnostic. */
6439 bool
6442 {
6447 {
6448 /* 7.3.3/18: The additional constructors are accessible if they would be
6449 accessible when used to construct an object of the corresponding base
6450 class. */
6454 }
6457 {
6459 {
6463 {
6469 }
6471 {
6477 }
6478 else
6479 {
6484 }
6485 }
6487 }
6490 }
6492 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6493 bitwise or of LOOKUP_* values. If any errors are warnings are
6494 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6495 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6496 to NULL. */
6498 static tree
6501 {
6507 /* If the source is a packed field, calling the copy constructor will require
6508 binding the field to the reference parameter to the copy constructor, and
6509 we'll end up with an infinite loop. If we can use a bitwise copy, then
6510 do that now. */
6526 }
6528 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6529 EXPR is implicitly converted to type TOTYPE.
6530 FN and ARGNUM are used for diagnostics. */
6532 static void
6534 {
6535 /* Issue warnings about peculiar, but valid, uses of NULL. */
6538 {
6539 source_location loc =
6546 else
6549 }
6551 /* Issue warnings if "false" is converted to a NULL pointer */
6554 {
6557 "converting %<false%> to pointer type for argument %P "
6559 else
6562 }
6563 }
6565 /* We gave a diagnostic during a conversion. If this was in the second
6566 standard conversion sequence of a user-defined conversion sequence, say
6567 which user-defined conversion. */
6569 static void
6571 {
6575 {
6579 }
6580 }
6582 /* Perform the conversions in CONVS on the expression EXPR. FN and
6583 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6584 indicates the `this' argument of a method. INNER is nonzero when
6585 being called to continue a conversion chain. It is negative when a
6586 reference binding will be applied, positive otherwise. If
6587 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6588 conversions will be emitted if appropriate. If C_CAST_P is true,
6589 this conversion is coming from a C-style cast; in that case,
6590 conversions to inaccessible bases are permitted. */
6592 static tree
6596 {
6598 diagnostic_t diag_kind;
6614 {
6618 /* Give a helpful error if this is bad because of excess braces. */
6623 {
6629 }
6631 /* Give a helpful error if this is bad because a conversion to bool
6632 from std::nullptr_t requires direct-initialization. */
6640 {
6642 {
6645 totype);
6651 complain);
6655 complain);
6656 else
6662 }
6664 {
6668 complain);
6670 }
6675 complain);
6678 }
6687 }
6693 {
6695 {
6699 /* We chose the surrogate function from add_conv_candidate, now we
6700 actually need to build the conversion. */
6706 /* When converting from an init list we consider explicit
6707 constructors, but actually trying to call one is an error. */
6710 /* Unless this is for direct-list-initialization. */
6712 /* And in C++98 a default constructor can't be explicit. */
6714 {
6720 {
6726 }
6727 else
6730 }
6732 /* If we're initializing from {}, it's value-initialization. */
6736 {
6741 {
6744 }
6746 }
6750 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6751 any more UDCs. */
6753 complain);
6755 /* If this is a constructor or a function returning an aggr type,
6756 we need to build up a TARGET_EXPR. */
6758 {
6761 /* Remember that this was list-initialization. */
6764 }
6767 }
6770 {
6776 else
6778 }
6785 /* We leave bad_p off ck_ambig because overload resolution considers
6786 it valid, it just fails when we try to perform it. So we need to
6787 check complain here, too. */
6789 {
6790 /* Call build_user_type_conversion again for the error. */
6792 complain);
6796 }
6800 {
6801 /* Conversion to std::initializer_list<T>. */
6809 /* Convert all the elements. */
6811 {
6822 }
6823 /* Build up the array. */
6824 elttype = cp_build_qualified_type
6828 /* Take the address explicitly rather than via decay_conversion
6829 to avoid the error about taking the address of a temporary. */
6835 /* Build up the initializer_list object. */
6843 }
6847 {
6856 }
6859 complain);
6866 };
6870 c_cast_p,
6871 complain);
6876 {
6880 {
6882 {
6887 }
6889 }
6894 /* Don't introduce copies when passing arguments along to the inherited
6895 constructor. */
6897 && flag_new_inheriting_ctors
6901 /* Fall through. */
6904 {
6905 /* We are going to bind a reference directly to a base-class
6906 subobject of EXPR. */
6907 /* Build an expression for `*((base*) &expr)'. */
6911 }
6913 /* Copy-initialization where the cv-unqualified version of the source
6914 type is the same class as, or a derived class of, the class of the
6915 destination [is treated as direct-initialization]. [dcl.init] */
6918 /* This conversion is being done in the context of a user-defined
6919 conversion (i.e. the second step of copy-initialization), so
6920 don't allow any more. */
6922 else
6925 /* standard_conversion got LOOKUP_PREFER_RVALUE. */
6929 /* Copy-list-initialization doesn't actually involve a copy. */
6933 {
6938 }
6943 {
6947 {
6960 else
6967 }
6969 /* If necessary, create a temporary.
6971 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6972 that need temporaries, even when their types are reference
6973 compatible with the type of reference being bound, so the
6974 upcoming call to cp_build_addr_expr doesn't fail. */
6978 {
6979 /* Otherwise, a temporary of type "cv1 T1" is created and
6980 initialized from the initializer expression using the rules
6981 for a non-reference copy-initialization (8.5). */
6990 {
6991 /* If the reference is volatile or non-const, we
6992 cannot create a temporary. */
6999 else
7003 }
7004 /* If the source is a packed field, and we must use a copy
7005 constructor, then building the target expr will require
7006 binding the field to the reference parameter to the
7007 copy constructor, and we'll end up with an infinite
7008 loop. If we can use a bitwise copy, then we'll be
7009 OK. */
7013 {
7017 }
7019 {
7022 }
7024 }
7026 /* Take the address of the thing to which we will bind the
7027 reference. */
7032 /* Convert it to a pointer to the type referred to by the
7033 reference. This will adjust the pointer if a derived to
7034 base conversion is being performed. */
7037 /* Convert the pointer to the desired reference type. */
7039 }
7045 /* ??? Should the address of a transaction-safe pointer point to the TM
7046 clone, and this conversion look up the primary function? */
7050 /* Warn about deprecated conversion if appropriate. */
7066 }
7074 else
7078 }
7080 /* ARG is being passed to a varargs function. Perform any conversions
7081 required. Return the converted value. */
7083 tree
7085 {
7086 tree arg_type;
7089 /* [expr.call]
7091 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7092 standard conversions are performed. */
7095 /* [expr.call]
7097 If the argument has integral or enumeration type that is subject
7098 to the integral promotions (_conv.prom_), or a floating point
7099 type that is subject to the floating point promotion
7100 (_conv.fpprom_), the value of the argument is converted to the
7101 promoted type before the call. */
7106 {
7110 "implicit conversion from %qH to %qI when passing "
7114 }
7118 {
7120 {
7122 complain);
7132 }
7133 else
7135 }
7141 /* In a template (or ill-formed code), we can have an incomplete type
7142 even after require_complete_type_sfinae, in which case we don't know
7143 whether it has trivial copy or not. */
7145 {
7146 /* Build up a real lvalue-to-rvalue conversion in case the
7147 copy constructor is trivial but not callable. */
7151 /* [expr.call] 5.2.2/7:
7152 Passing a potentially-evaluated argument of class type (Clause 9)
7153 with a non-trivial copy constructor or a non-trivial destructor
7154 with no corresponding parameter is conditionally-supported, with
7155 implementation-defined semantics.
7157 We support it as pass-by-invisible-reference, just like a normal
7158 value parameter.
7160 If the call appears in the context of a sizeof expression,
7161 it is not potentially-evaluated. */
7165 {
7168 "passing objects of non-trivially-copyable "
7170 arg_type);
7172 }
7173 }
7176 }
7178 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7180 tree
7182 {
7184 {
7188 }
7198 {
7201 }
7205 {
7206 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7207 it as pass by invisible reference. */
7209 "receiving objects of non-trivially-copyable type %q#T "
7215 }
7219 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7220 know how to handle it. */
7223 }
7225 /* TYPE has been given to va_arg. Apply the default conversions which
7226 would have happened when passed via ellipsis. Return the promoted
7227 type, or the passed type if there is no change. */
7229 tree
7231 {
7232 tree promote;
7234 /* Perform the array-to-pointer and function-to-pointer
7235 conversions. */
7243 }
7245 /* ARG is a default argument expression being passed to a parameter of
7246 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7247 zero-based argument number. Do any required conversions. Return
7248 the converted value. */
7251 void
7255 void
7259 tree
7261 tsubst_flags_t complain)
7262 {
7264 tree t;
7266 /* See through clones. */
7268 /* And inheriting ctors. */
7272 /* Detect recursion. */
7275 {
7279 }
7281 /* If the ARG is an unparsed default argument expression, the
7282 conversion cannot be performed. */
7284 {
7289 }
7296 /* Due to:
7298 [dcl.fct.default]
7300 The names in the expression are bound, and the semantic
7301 constraints are checked, at the point where the default
7302 expressions appears.
7304 we must not perform access checks here. */
7306 /* We must make a copy of ARG, in case subsequent processing
7307 alters any part of it. */
7311 complain);
7318 }
7320 /* Returns the type which will really be used for passing an argument of
7321 type TYPE. */
7323 tree
7325 {
7326 /* Pass classes with copy ctors by invisible reference. */
7328 {
7330 /* There are no other pointers to this temporary. */
7332 }
7340 }
7342 /* Actually perform the appropriate conversion. */
7344 tree
7346 {
7347 tree bitfield_type;
7349 /* If VAL is a bitfield, then -- since it has already been converted
7350 to TYPE -- it cannot have a precision greater than TYPE.
7352 If it has a smaller precision, we must widen it here. For
7353 example, passing "int f:3;" to a function expecting an "int" will
7354 not result in any conversion before this point.
7356 If the precision is the same we must not risk widening. For
7357 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7358 often have type "int", even though the C++ type for the field is
7359 "long long". If the value is being passed to a function
7360 expecting an "int", then no conversions will be required. But,
7361 if we call convert_bitfield_to_declared_type, the bitfield will
7362 be converted to "long long". */
7369 ;
7370 /* Pass classes with copy ctors by invisible reference. */
7379 {
7381 {
7389 "argument of function call might be a candidate "
7391 }
7393 }
7395 }
7397 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7398 which just decay_conversion or no conversions at all should be done.
7399 This is true for some builtins which don't act like normal functions.
7400 Return 2 if no conversions at all should be done, 1 if just
7401 decay_conversion. Return 3 for special treatment of the 3rd argument
7402 for __builtin_*_overflow_p. */
7404 int
7406 {
7412 {
7427 }
7430 }
7432 /* Returns the decl of the dispatcher function if FN is a function version. */
7434 tree
7436 {
7446 {
7450 }
7455 }
7457 /* fn is a function version dispatcher that is marked used. Mark all the
7458 semantically identical function versions it will dispatch as used. */
7460 void
7462 {
7479 /* All semantically identical versions are chained. Traverse and mark each
7480 one of them as used. */
7483 {
7486 }
7487 }
7489 /* Build a call to "the copy constructor" for the type of A, even if it
7490 wouldn't be selected by normal overload resolution. Used for
7491 diagnostics. */
7493 static tree
7495 {
7506 }
7508 /* Return true iff T refers to a base field. */
7510 static bool
7512 {
7521 }
7523 /* We can't elide a copy from a function returning by value to a base
7524 subobject, as the callee might clobber tail padding. Return true iff this
7525 could be that case. */
7527 static bool
7529 {
7530 /* Copy elision only happens with a TARGET_EXPR. */
7534 /* It's safe to elide the copy for a class with no tail padding. */
7537 /* It's safe to elide the copy if we aren't initializing a base object. */
7541 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7546 }
7548 /* Subroutine of the various build_*_call functions. Overload resolution
7549 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7550 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7551 bitmask of various LOOKUP_* flags which apply to the call itself. */
7553 static tree
7555 {
7563 tree val;
7572 /* In a template, there is no need to perform all of the work that
7573 is normally done. We are only interested in the type of the call
7574 expression, i.e., the return type of the function. Any semantic
7575 errors will be deferred until the template is instantiated. */
7577 {
7579 tree return_type;
7590 else
7591 {
7594 tree arg;
7602 }
7612 }
7614 /* Give any warnings we noticed during overload resolution. */
7616 {
7620 }
7622 /* OK, we're actually calling this inherited constructor; set its deletedness
7623 appropriately. We can get away with doing this here because calling is
7624 the only way to refer to a constructor. */
7628 /* Make =delete work with SFINAE. */
7633 {
7634 tree access_fn;
7635 /* If FN is a template function, two cases must be considered.
7636 For example:
7638 struct A {
7639 protected:
7640 template <class T> void f();
7641 };
7642 template <class T> struct B {
7643 protected:
7644 void g();
7645 };
7646 struct C : A, B<int> {
7647 using A::f; // #1
7648 using B<int>::g; // #2
7649 };
7651 In case #1 where `A::f' is a member template, DECL_ACCESS is
7652 recorded in the primary template but not in its specialization.
7653 We check access of FN using its primary template.
7655 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7656 because it is a member of class template B, DECL_ACCESS is
7657 recorded in the specialization `B<int>::g'. We cannot use its
7658 primary template because `B<T>::g' and `B<int>::g' may have
7659 different access. */
7663 else
7668 }
7670 /* If we're checking for implicit delete, don't bother with argument
7671 conversions. */
7673 {
7675 {
7679 }
7683 /* Reject bad conversions now. */
7685 /* else continue to get conversion error. */
7686 }
7688 /* N3276 magic doesn't apply to nested calls. */
7692 /* Find maximum size of vector to hold converted arguments. */
7699 /* The implicit parameters to a constructor are not considered by overload
7700 resolution, and must be of the proper type. */
7702 {
7703 tree object_arg;
7705 {
7708 }
7709 else
7710 {
7713 }
7716 /* We should never try to call the abstract constructor. */
7720 {
7724 }
7727 {
7728 /* The implicit move specified in 15.8.3/3 fails "...if the type of
7729 the first parameter of the selected constructor is not an rvalue
7730 reference to the object’s type (possibly cv-qualified)...." */
7737 }
7738 }
7739 /* Bypass access control for 'this' parameter. */
7741 {
7744 ? first_arg
7747 tree converted_arg;
7748 tree base_binfo;
7751 {
7753 {
7758 }
7759 else
7761 }
7763 /* See if the function member or the whole class type is declared
7764 final and the call can be devirtualized. */
7769 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7770 X is called for an object that is not of type X, or of a type
7771 derived from X, the behavior is undefined.
7773 So we can assume that anything passed as 'this' is non-null, and
7774 optimize accordingly. */
7776 /* Convert to the base in which the function was declared. */
7779 arg,
7782 /* Check that the base class is accessible. */
7785 {
7790 else
7792 }
7793 /* If fn was found by a using declaration, the conversion path
7794 will be to the derived class, not the base declaring fn. We
7795 must convert from derived to base. */
7806 else
7810 }
7815 {
7822 /* If the argument is NULL and used to (implicitly) instantiate a
7823 template function (and bind one of the template arguments to
7824 the type of 'long int'), we don't want to warn about passing NULL
7825 to non-pointer argument.
7826 For example, if we have this template function:
7828 template<typename T> void func(T x) {}
7830 we want to warn (when -Wconversion is enabled) in this case:
7832 void foo() {
7833 func<int>(NULL);
7834 }
7836 but not in this case:
7838 void foo() {
7839 func(NULL);
7840 }
7841 */
7848 /* Warn about initializer_list deduction that isn't currently in the
7849 working draft. */
7851 && flag_deduce_init_list
7855 {
7868 {
7876 }
7877 }
7879 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7880 knows not to allow any more UDCs. This needs to happen after we
7881 process cand->warnings. */
7890 arg_complain);
7895 else
7897 }
7899 /* Default arguments */
7901 {
7907 complain);
7911 }
7913 /* Ellipsis */
7916 {
7919 {
7920 /* Do no conversions for certain magic varargs. */
7924 }
7926 /* For other magic varargs only do decay_conversion. */
7931 {
7932 /* Avoid infinite recursion trying to call A(...). */
7934 /* Try to call the actual copy constructor for a good error. */
7937 }
7938 else
7943 }
7948 /* Avoid to do argument-transformation, if warnings for format, and for
7949 nonnull are disabled. Just in case that at least one of them is active
7950 the check_function_arguments function might warn about something. */
7954 || warn_format
7955 || warn_suggest_attribute_format
7957 {
7965 }
7968 {
7969 /* Check for passing ellipsis arguments to an inherited constructor. We
7970 could handle this by open-coding the inherited constructor rather than
7971 defining it, but let's not bother now. */
7975 {
7977 {
7981 }
7983 }
7985 /* A base constructor inheriting from a virtual base doesn't get the
7986 inherited arguments, just this and __vtt. */
7989 }
7991 /* Avoid actually calling copy constructors and copy assignment operators,
7992 if possible. */
7999 /* It's unsafe to elide the constructor when handling
8000 a noexcept-expression, it may evaluate to the wrong
8001 value (c++/53025). */
8003 {
8004 tree targ;
8006 tree fa;
8009 /* Pull out the real argument, disregarding const-correctness. */
8011 /* Strip the reference binding for the constructor parameter. */
8015 /* But don't strip any other reference bindings; binding a temporary to a
8016 reference prevents copy elision. */
8022 {
8027 }
8028 else
8033 else
8036 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8037 subobject. */
8040 /* It's from binding the ref parm to a packed field. */
8043 /* See unsafe_copy_elision_p. */
8046 /* [class.copy]: the copy constructor is implicitly defined even if
8047 the implementation elided its use. */
8049 {
8053 }
8055 /* If we're creating a temp and we already have one, don't create a
8056 new one. If we're not creating a temp but we get one, use
8057 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8058 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8059 temp or an INIT_EXPR otherwise. */
8062 {
8067 }
8070 {
8072 RO_NULL,
8073 complain));
8077 }
8078 }
8082 {
8083 tree to = cp_stabilize_reference
8090 {
8091 /* Avoid copying empty classes. */
8094 }
8096 {
8099 /* Handle NSDMI that refer to the object being initialized. */
8101 }
8102 else
8103 {
8104 /* We must only copy the non-tail padding parts. */
8112 build_index_type
8121 }
8124 }
8127 {
8131 {
8134 else
8136 }
8137 }
8139 /* For calls to a multi-versioned function, overload resolution
8140 returns the function with the highest target priority, that is,
8141 the version that will checked for dispatching first. If this
8142 version is inlinable, a direct call to this version can be made
8143 otherwise the call should go through the dispatcher. */
8148 {
8154 }
8161 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8162 virtual functions can't be constexpr. */
8164 {
8165 tree t;
8172 complain);
8178 }
8179 else
8180 {
8184 }
8190 {
8192 /* build_new_op_1 will clear this when appropriate. */
8194 }
8196 {
8200 }
8202 }
8204 /* Return the DECL of the first non-public data member of class TYPE
8205 or null if none can be found. */
8207 static tree
8209 {
8214 {
8221 }
8227 {
8232 }
8235 }
8237 /* Return true if all copy and move assignment operator overloads for
8238 class TYPE are trivial and at least one of them is not deleted and,
8239 when ACCESS is set, accessible. Return false otherwise. Set
8240 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8241 copy or move assignment. */
8243 static bool
8245 {
8249 /* Iterate over overloads of the assignment operator, checking
8250 accessible copy assignments for triviality. */
8253 {
8256 /* Skip operators that aren't copy assignments. */
8263 /* Skip template assignment operators and deleted functions. */
8273 /* Break early when both properties have been determined. */
8276 }
8278 /* Return true if they're all trivial and one of the expressions
8279 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8284 }
8286 /* Return true if all copy and move ctor overloads for class TYPE are
8287 trivial and at least one of them is not deleted and, when ACCESS is
8288 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8289 to true when the TYPE has a (not necessarily trivial) default and copy
8290 (or move) ctor, respectively. */
8292 static bool
8294 {
8299 {
8302 /* Skip template constructors. */
8308 /* Skip ctors other than default, copy, and move. */
8324 /* Break early when both properties have been determined. */
8327 }
8330 }
8332 /* Issue a warning on a call to the built-in function FNDECL if it is
8333 a raw memory write whose destination is not an object of (something
8334 like) trivial or standard layout type with a non-deleted assignment
8335 and copy ctor. Detects const correctness violations, corrupting
8336 references, virtual table pointers, and bypassing non-trivial
8337 assignments. */
8339 static void
8341 {
8342 /* Except for bcopy where it's second, the destination pointer is
8343 the first argument for all functions handled here. Compute
8344 the index of the destination and source arguments. */
8352 /* Remove the outermost (usually implicit) conversion to the void*
8353 argument type. */
8359 /* Determine the type of the pointed-to object and whether it's
8360 a complete class type. */
8366 /* Check to see if the raw memory call is made by a ctor or dtor
8367 with this as the destination argument for the destination type.
8368 If so, be more permissive. */
8373 {
8379 /* A ctor and dtor for a class with no bases and no virtual functions
8380 can do whatever they want. Bail early with no further checking. */
8383 }
8385 /* True if the class is trivial. */
8388 /* Set to true if DESTYPE has an accessible copy assignment. */
8390 /* True if all of the class' overloaded copy assignment operators
8391 are all trivial (and not deleted) and at least one of them is
8392 accessible. */
8395 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8396 respectively. */
8399 /* True if all of the class' overloaded copy constructors are all
8400 trivial (and not deleted) and at least one of them is accessible. */
8403 /* Set FLD to the first private/protected member of the class. */
8406 /* The warning format string. */
8408 /* A suggested alternative to offer instead of the raw memory call.
8409 Empty string when none can be come up with. */
8414 {
8417 {
8418 /* Diagnose setting non-copy-assignable or non-trivial types,
8419 or types with a private member, to (potentially) non-zero
8420 bytes. Since the value of the bytes being written is unknown,
8421 suggest using assignment instead (if one exists). Also warn
8422 for writes into objects for which zero-initialization doesn't
8423 mean all bits clear (pointer-to-member data, where null is all
8424 bits set). Since the value being written is (most likely)
8425 non-zero, simply suggest assignment (but not copy assignment). */
8433 {
8436 "%qD writing to an object of type %#qT with "
8439 }
8445 }
8446 /* Fall through. */
8449 /* Similarly to the above, diagnose clearing non-trivial or non-
8450 standard layout objects, or objects of types with no assignmenmt.
8451 Since the value being written is known to be zero, suggest either
8452 copy assignment, copy ctor, or default ctor as an alternative,
8453 depending on what's available. */
8476 /* Determine the type of the source object. */
8480 /* Since it's impossible to determine wheter the byte copy is
8481 being used in place of assignment to an existing object or
8482 as a substitute for initialization, assume it's the former.
8483 Determine the best alternative to use instead depending on
8484 what's not deleted. */
8505 srctype))
8506 {
8507 /* Warn when copying into a non-trivial object from an object
8508 of a different type other than void or char. */
8510 "%qD copying an object of non-trivial type "
8513 }
8518 srctype))
8519 {
8522 "%qD copying an object of type %#qT with "
8523 "%qs member %qD from an array of %#qT; use "
8526 }
8528 {
8529 /* Finally, warn on partial copies. */
8530 unsigned HOST_WIDE_INT typesize
8537 "a non-trivial type %#qT leaves %wu "
8540 "a non-trivial type %#qT leaves %wu "
8543 }
8560 {
8561 /* Finally, warn on reallocation into insufficient space. */
8563 "%qD moving an object of non-trivial type "
8567 }
8572 }
8578 {
8582 else
8585 }
8589 }
8591 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8592 This function performs no overload resolution, conversion, or other
8593 high-level operations. */
8595 tree
8597 tsubst_flags_t complain)
8598 {
8599 tree fndecl;
8601 /* Remember roughly where this call is. */
8608 /* Check that arguments to builtin functions match the expectations. */
8612 {
8615 /* We need to take care that values to BUILT_IN_NORMAL
8616 are reduced. */
8624 /* Warn if the built-in writes to an object of a non-trivial type. */
8627 }
8629 /* If it is a built-in array notation function, then the return type of
8630 the function is the element type of the array passed in as array
8631 notation (i.e. the first parameter of the function). */
8633 {
8642 {
8644 {
8647 }
8648 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8649 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8650 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8651 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8652 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8653 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8654 The pre-defined return-type is the correct one. */
8658 }
8659 }
8664 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8665 function call is either the operand of a decltype-specifier or the
8666 right operand of a comma operator that is the operand of a
8667 decltype-specifier, a temporary object is not introduced for the
8668 prvalue. The type of the prvalue may be incomplete. */
8670 {
8676 {
8679 }
8680 }
8682 }
8684 /* Returns the value to use for the in-charge parameter when making a
8685 call to a function with the indicated NAME.
8687 FIXME:Can't we find a neater way to do this mapping? */
8689 tree
8691 {
8693 {
8697 }
8698 else
8699 {
8705 }
8708 }
8710 /* We've built up a constructor call RET. Complain if it delegates to the
8711 constructor we're currently compiling. */
8713 static void
8715 {
8721 }
8723 /* Build a call to a constructor, destructor, or an assignment
8724 operator for INSTANCE, an expression with class type. NAME
8725 indicates the special member function to call; *ARGS are the
8726 arguments. ARGS may be NULL. This may change ARGS. BINFO
8727 indicates the base of INSTANCE that is to be passed as the `this'
8728 parameter to the member function called.
8730 FLAGS are the LOOKUP_* flags to use when processing the call.
8732 If NAME indicates a complete object constructor, INSTANCE may be
8733 NULL_TREE. In this case, the caller will call build_cplus_new to
8734 store the newly constructed object into a VAR_DECL. */
8736 tree
8739 {
8740 tree fns;
8741 /* The type of the subobject to be constructed or destroyed. */
8742 tree class_type;
8744 tree ret;
8749 {
8750 /* Resolve the name. */
8755 }
8761 /* Handle the special case where INSTANCE is NULL_TREE. */
8764 else
8765 {
8769 /* Convert to the base class, if necessary. */
8772 {
8774 /* For constructors and destructors, either the base is
8775 non-virtual, or it is virtual but we are doing the
8776 conversion from a constructor or destructor for the
8777 complete object. In either case, we can convert
8778 statically. */
8780 else
8781 /* However, for assignment operators, we must convert
8782 dynamically if the base is virtual. */
8785 }
8786 }
8790 /* In C++17, "If the initializer expression is a prvalue and the
8791 cv-unqualified version of the source type is the same class as the class
8792 of the destination, the initializer expression is used to initialize the
8793 destination object." Handle that here to avoid doing overload
8794 resolution. */
8798 {
8801 /* FIXME P0135 doesn't say how to handle direct initialization from a
8802 type with a suitable conversion operator. Let's handle it like
8803 copy-initialization, but allowing explict conversions. */
8806 /* If we're using this to initialize a non-temporary object, don't
8807 require the destructor to be accessible. */
8811 sub_complain,
8812 flags);
8815 && (same_type_ignoring_top_level_qualifiers_p
8817 {
8823 /* Avoid change of behavior on Wunused-var-2.C. */
8826 }
8827 }
8831 /* When making a call to a constructor or destructor for a subobject
8832 that uses virtual base classes, pass down a pointer to a VTT for
8833 the subobject. */
8837 {
8838 tree vtt;
8839 tree sub_vtt;
8841 /* If the current function is a complete object constructor
8842 or destructor, then we fetch the VTT directly.
8843 Otherwise, we look it up using the VTT we were given. */
8851 else
8855 {
8858 }
8861 }
8866 complain);
8877 }
8879 /* Return the NAME, as a C string. The NAME indicates a function that
8880 is a member of TYPE. *FREE_P is set to true if the caller must
8881 free the memory returned.
8883 Rather than go through all of this, we should simply set the names
8884 of constructors and destructors appropriately, and dispense with
8885 ctor_identifier, dtor_identifier, etc. */
8889 {
8892 /* Assume that we will not allocate memory. */
8894 /* Constructors and destructors are special. */
8896 {
8897 pretty_name
8899 /* For a destructor, add the '~'. */
8901 {
8903 /* Remember that we need to free the memory allocated. */
8905 }
8906 }
8908 {
8911 TFF_PLAIN_IDENTIFIER),
8912 NULL);
8913 /* Remember that we need to free the memory allocated. */
8915 }
8916 else
8920 }
8922 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8923 be set, upon return, to the function called. ARGS may be NULL.
8924 This may change ARGS. */
8926 static tree
8930 {
8935 tree optype;
8937 tree name;
8940 tree call;
8941 tree fn;
8944 tree orig_instance;
8945 tree orig_fns;
8951 /* We don't know what function we're going to call, yet. */
8960 {
8964 }
8969 /* Dismantle the baselink to collect all the information we need. */
8977 {
8981 }
8992 {
8997 }
9000 /* Under DR 147 A::A() is an invalid constructor call,
9001 not a functional cast. */
9003 {
9015 complain);
9017 }
9019 /* Process the argument list. */
9021 {
9025 }
9027 /* Consider the object argument to be used even if we end up selecting a
9028 static member function. */
9032 /* Figure out whether to skip the first argument for the error
9033 message we will display to users if an error occurs. We don't
9034 want to display any compiler-generated arguments. The "this"
9035 pointer hasn't been added yet. However, we must remove the VTT
9036 pointer if this is a call to a base-class constructor or
9037 destructor. */
9040 {
9041 /* Callers should explicitly indicate whether they want to ctor
9042 the complete object or just the part without virtual bases. */
9045 /* Remove the VTT pointer, if present. */
9050 /* It's OK to call destructors and constructors on cv-qualified
9051 objects. Therefore, convert the INSTANCE to the unqualified
9052 type, if necessary. */
9054 {
9058 }
9059 }
9060 else
9063 /* For the overload resolution we need to find the actual `this`
9064 that would be captured if the call turns out to be to a
9065 non-static member function. Do not actually capture it at this
9066 point. */
9068 /* Constructors don't use the enclosing 'this'. */
9070 else
9073 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9076 /* The number of arguments artificial parms in ARGS; we subtract one because
9077 there's no 'this' in ARGS. */
9080 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9081 initializer, not T({ }). */
9085 {
9092 /* If the initializer list has no elements and T is a class type with
9093 a default constructor, the object is value-initialized. Handle
9094 this here so we don't need to handle it wherever we use
9095 build_special_member_call. */
9098 /* For a user-provided default constructor, use the normal
9099 mechanisms so that protected access works. */
9104 /* If BASETYPE is an aggregate, we need to do aggregate
9105 initialization. */
9107 {
9110 }
9113 {
9119 }
9121 /* Otherwise go ahead with overload resolution. */
9126 }
9127 else
9136 {
9138 {
9145 else
9146 {
9151 {
9154 }
9162 }
9164 }
9166 }
9167 else
9168 {
9171 {
9174 tree arglist;
9177 {
9185 else
9191 }
9193 }
9194 else
9195 {
9203 {
9204 /* This is not an error, it is runtime undefined
9205 behavior. */
9214 fn);
9215 }
9220 {
9225 {
9226 /* We captured 'this' in the current lambda now that
9227 we know we really need it. */
9229 }
9231 /* We can't tell until instantiation time whether we can use
9233 else
9234 {
9237 fn);
9239 }
9240 }
9243 {
9244 /* Optimize away vtable lookup if we know that this
9245 function can't be overridden. We need to check if
9246 the context and the type where we found fn are the same,
9247 actually FN might be defined in a different class
9248 type because of a using-declaration. In this case, we
9249 do not want to perform a non-virtual call. */
9251 && same_type_ignoring_top_level_qualifiers_p
9257 /* Now we know what function is being called. */
9260 /* Build the actual CALL_EXPR. */
9262 /* In an expression of the form `a->f()' where `f' turns
9263 out to be a static member function, `a' is
9264 none-the-less evaluated. */
9273 /* An explicit call of the form "x->~X()" has type
9274 "void". However, on platforms where destructors
9275 return "this" (i.e., those where
9276 targetm.cxx.cdtor_returns_this is true), such calls
9277 will appear to have a return value of pointer type
9278 to the low-level call machinery. We do not want to
9279 change the low-level machinery, since we want to be
9280 able to optimize "delete f()" on such platforms as
9281 "operator delete(~X(f()))" (rather than generating
9282 "t = f(), ~X(t), operator delete (t)"). */
9284 }
9285 }
9286 }
9289 {
9295 {
9298 }
9301 call = (build_min_non_dep_call_vec
9305 orig_args));
9310 }
9312 /* Free all the conversions we allocated. */
9319 }
9321 /* Wrapper for above. */
9323 tree
9327 {
9328 tree ret;
9334 }
9336 /* Returns true iff standard conversion sequence ICS1 is a proper
9337 subsequence of ICS2. */
9339 static bool
9341 {
9342 /* We can assume that a conversion of the same code
9343 between the same types indicates a subsequence since we only get
9344 here if the types we are converting from are the same. */
9351 {
9361 /* At this point, ICS1 cannot be a proper subsequence of
9362 ICS2. We can get a USER_CONV when we are comparing the
9363 second standard conversion sequence of two user conversion
9364 sequences. */
9379 }
9380 }
9382 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9383 be any _TYPE nodes. */
9385 bool
9387 {
9391 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9392 considers every class derived from itself. */
9395 }
9397 /* We build the ICS for an implicit object parameter as a pointer
9398 conversion sequence. However, such a sequence should be compared
9399 as if it were a reference conversion sequence. If ICS is the
9400 implicit conversion sequence for an implicit object parameter,
9401 modify it accordingly. */
9403 static void
9405 {
9407 {
9408 /* [over.match.funcs]
9410 For non-static member functions, the type of the
9411 implicit object parameter is "reference to cv X"
9412 where X is the class of which the function is a
9413 member and cv is the cv-qualification on the member
9414 function declaration. */
9416 tree reference_type;
9418 /* The `this' parameter is a pointer to a class type. Make the
9419 implicit conversion talk about a reference to that same class
9420 type. */
9433 }
9434 }
9436 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9437 and return the initial reference binding conversion. Otherwise,
9438 leave *ICS unchanged and return NULL. */
9442 {
9444 {
9449 }
9452 }
9454 /* Compare two implicit conversion sequences according to the rules set out in
9455 [over.ics.rank]. Return values:
9457 1: ics1 is better than ics2
9458 -1: ics2 is better than ics1
9459 0: ics1 and ics2 are indistinguishable */
9461 static int
9463 {
9464 tree from_type1;
9465 tree from_type2;
9466 tree to_type1;
9467 tree to_type2;
9474 /* REF_BINDING is nonzero if the result of the conversion sequence
9475 is a reference type. In that case REF_CONV is the reference
9476 binding conversion. */
9480 /* Compare badness before stripping the reference conversion. */
9486 /* Handle implicit object parameters. */
9490 /* Handle reference parameters. */
9494 /* List-initialization sequence L1 is a better conversion sequence than
9495 list-initialization sequence L2 if L1 converts to
9496 std::initializer_list<X> for some X and L2 does not. */
9502 /* [over.ics.rank]
9504 When comparing the basic forms of implicit conversion sequences (as
9505 defined in _over.best.ics_)
9507 --a standard conversion sequence (_over.ics.scs_) is a better
9508 conversion sequence than a user-defined conversion sequence
9509 or an ellipsis conversion sequence, and
9511 --a user-defined conversion sequence (_over.ics.user_) is a
9512 better conversion sequence than an ellipsis conversion sequence
9513 (_over.ics.ellipsis_). */
9514 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9515 mismatch. If both ICS are bad, we try to make a decision based on
9516 what would have happened if they'd been good. This is not an
9517 extension, we'll still give an error when we build up the call; this
9518 just helps us give a more helpful error message. */
9528 /* Both conversions are ellipsis conversions. */
9531 /* User-defined conversion sequence U1 is a better conversion sequence
9532 than another user-defined conversion sequence U2 if they contain the
9533 same user-defined conversion operator or constructor and if the sec-
9534 ond standard conversion sequence of U1 is better than the second
9535 standard conversion sequence of U2. */
9537 /* Handle list-conversion with the same code even though it isn't always
9538 ranked as a user-defined conversion and it doesn't have a second
9539 standard conversion sequence; it will still have the desired effect.
9540 Specifically, we need to do the reference binding comparison at the
9541 end of this function. */
9544 {
9560 {
9565 }
9566 else
9567 {
9568 /* For ambiguous or aggregate conversions, use the target type as
9569 a proxy for the conversion function. */
9572 }
9574 /* We can just fall through here, after setting up
9575 FROM_TYPE1 and FROM_TYPE2. */
9578 }
9579 else
9580 {
9584 /* We're dealing with two standard conversion sequences.
9586 [over.ics.rank]
9588 Standard conversion sequence S1 is a better conversion
9589 sequence than standard conversion sequence S2 if
9591 --S1 is a proper subsequence of S2 (comparing the conversion
9592 sequences in the canonical form defined by _over.ics.scs_,
9593 excluding any Lvalue Transformation; the identity
9594 conversion sequence is considered to be a subsequence of
9595 any non-identity conversion sequence */
9606 }
9608 /* One sequence can only be a subsequence of the other if they start with
9609 the same type. They can start with different types when comparing the
9610 second standard conversion sequence in two user-defined conversion
9611 sequences. */
9613 {
9618 }
9620 /* [over.ics.rank]
9622 Or, if not that,
9624 --the rank of S1 is better than the rank of S2 (by the rules
9625 defined below):
9627 Standard conversion sequences are ordered by their ranks: an Exact
9628 Match is a better conversion than a Promotion, which is a better
9629 conversion than a Conversion.
9631 Two conversion sequences with the same rank are indistinguishable
9632 unless one of the following rules applies:
9634 --A conversion that does not a convert a pointer, pointer to member,
9635 or std::nullptr_t to bool is better than one that does.
9637 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9638 so that we do not have to check it explicitly. */
9647 /* A conversion from scalar arithmetic type to complex is worse than a
9648 conversion between scalar arithmetic types. */
9655 {
9658 else
9660 }
9666 {
9671 }
9672 /* The rules for pointers to members A::* are just like the rules
9673 for pointers A*, except opposite: if B is derived from A then
9674 A::* converts to B::*, not vice versa. For that reason, we
9675 switch the from_ and to_ variables here. */
9682 {
9687 }
9692 {
9693 /* This was one of the pointer or pointer-like conversions.
9695 [over.ics.rank]
9697 --If class B is derived directly or indirectly from class A,
9698 conversion of B* to A* is better than conversion of B* to
9699 void*, and conversion of A* to void* is better than
9700 conversion of B* to void*. */
9703 {
9705 deref_from_type2))
9708 deref_from_type1))
9710 }
9713 {
9715 {
9717 {
9719 deref_to_type1))
9721 }
9722 /* We know that DEREF_TO_TYPE1 is `void' here. */
9724 deref_to_type2))
9726 }
9727 }
9730 {
9731 /* [over.ics.rank]
9733 --If class B is derived directly or indirectly from class A
9734 and class C is derived directly or indirectly from B,
9736 --conversion of C* to B* is better than conversion of C* to
9737 A*,
9739 --conversion of B* to A* is better than conversion of C* to
9740 A* */
9742 {
9744 deref_to_type2))
9747 deref_to_type1))
9749 }
9751 {
9753 deref_from_type1))
9756 deref_from_type2))
9758 }
9759 }
9760 }
9763 {
9766 /* [over.ics.rank]
9768 --binding of an expression of type C to a reference of type
9769 B& is better than binding an expression of type C to a
9770 reference of type A&
9772 --conversion of C to B is better than conversion of C to A, */
9775 {
9780 }
9781 }
9784 {
9787 /* [over.ics.rank]
9789 --binding of an expression of type B to a reference of type
9790 A& is better than binding an expression of type C to a
9791 reference of type A&,
9793 --conversion of B to A is better than conversion of C to A */
9796 {
9801 }
9802 }
9804 /* [over.ics.rank]
9806 --S1 and S2 differ only in their qualification conversion and yield
9807 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9808 qualification signature of type T1 is a proper subset of the cv-
9809 qualification signature of type T2 */
9813 {
9817 }
9819 /* [over.ics.rank]
9821 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9822 to an implicit object parameter of a non-static member function
9823 declared without a ref-qualifier, and either S1 binds an lvalue
9824 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9825 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9826 draft standard, 13.3.3.2)
9828 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9829 types to which the references refer are the same type except for
9830 top-level cv-qualifiers, and the type to which the reference
9831 initialized by S2 refers is more cv-qualified than the type to
9832 which the reference initialized by S1 refers.
9834 DR 1328 [over.match.best]: the context is an initialization by
9835 conversion function for direct reference binding (13.3.1.6) of a
9836 reference to function type, the return type of F1 is the same kind of
9837 reference (i.e. lvalue or rvalue) as the reference being initialized,
9838 and the return type of F2 is not. */
9841 {
9848 {
9852 /* Don't prefer a bad conversion that drops cv-quals to a bad
9853 conversion with the wrong rvalueness. */
9857 }
9860 {
9864 {
9865 /* Prefer the one that drops fewer cv-quals. */
9870 }
9872 }
9873 }
9875 /* Neither conversion sequence is better than the other. */
9877 }
9879 /* The source type for this standard conversion sequence. */
9881 static tree
9883 {
9885 {
9890 }
9892 }
9894 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9895 a pointer to LOSER and re-running joust to produce the warning if WINNER
9896 is actually used. */
9898 static void
9900 {
9906 }
9908 /* Compare two candidates for overloading as described in
9909 [over.match.best]. Return values:
9911 1: cand1 is better than cand2
9912 -1: cand2 is better than cand1
9913 0: cand1 and cand2 are indistinguishable */
9915 static int
9917 tsubst_flags_t complain)
9918 {
9924 /* Candidates that involve bad conversions are always worse than those
9925 that don't. */
9931 /* If we have two pseudo-candidates for conversions to the same type,
9932 or two candidates for the same function, arbitrarily pick one. */
9937 /* Prefer a non-deleted function over an implicitly deleted move
9938 constructor or assignment operator. This differs slightly from the
9939 wording for issue 1402 (which says the move op is ignored by overload
9940 resolution), but this way produces better error messages. */
9944 {
9951 }
9953 /* a viable function F1
9954 is defined to be a better function than another viable function F2 if
9955 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9956 ICSi(F2), and then */
9958 /* for some argument j, ICSj(F1) is a better conversion sequence than
9959 ICSj(F2) */
9961 /* For comparing static and non-static member functions, we ignore
9962 the implicit object parameter of the non-static function. The
9963 standard says to pretend that the static function has an object
9964 parm, but that won't work with operator overloading. */
9967 {
9973 /* We're comparing a near-match list constructor and a near-match
9974 non-list constructor. Just treat them as unordered. */
9981 else
9982 {
9985 }
9986 }
9989 {
9995 {
9997 && warn_sign_promo
10009 {
10016 else
10021 {
10025 }
10026 else
10028 }
10031 {
10034 }
10036 }
10037 }
10039 /* warn about confusing overload resolution for user-defined conversions,
10040 either between a constructor and a conversion op, or between two
10041 conversion ops. */
10046 {
10052 else
10055 /* We don't want to complain about `X::operator T1 ()'
10056 beating `X::operator T2 () const', when T2 is a no less
10057 cv-qualified version of T1. */
10060 {
10065 {
10068 }
10071 }
10072 else
10078 {
10085 {
10087 }
10088 }
10089 else
10091 }
10096 /* DR 495 moved this tiebreaker above the template ones. */
10097 /* or, if not that,
10098 the context is an initialization by user-defined conversion (see
10099 _dcl.init_ and _over.match.user_) and the standard conversion
10100 sequence from the return type of F1 to the destination type (i.e.,
10101 the type of the entity being initialized) is a better conversion
10102 sequence than the standard conversion sequence from the return type
10103 of F2 to the destination type. */
10106 {
10110 }
10112 /* or, if not that,
10113 F1 is a non-template function and F2 is a template function
10114 specialization. */
10121 /* or, if not that,
10122 F1 and F2 are template functions and the function template for F1 is
10123 more specialized than the template for F2 according to the partial
10124 ordering rules. */
10127 {
10128 winner = more_specialized_fn
10131 /* [temp.func.order]: The presence of unused ellipsis and default
10132 arguments has no effect on the partial ordering of function
10133 templates. add_function_candidate() will not have
10134 counted the "this" argument for constructors. */
10138 }
10140 // C++ Concepts
10141 // or, if not that, F1 is more constrained than F2.
10143 {
10147 }
10149 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10151 {
10153 /* We distinguish between candidates from an explicit deduction guide and
10154 candidates built from a constructor based on DECL_ARTIFICIAL. */
10161 {
10162 /* Prefer the special copy guide over a declared copy/move
10163 constructor. */
10169 /* Prefer a candidate generated from a non-template constructor. */
10174 }
10175 }
10177 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10178 for all arguments the corresponding parameters of F1 and F2 have the same
10179 type (CWG 2273/2277). */
10184 {
10198 {
10200 {
10205 }
10208 }
10209 }
10211 /* Check whether we can discard a builtin candidate, either because we
10212 have two identical ones or matching builtin and non-builtin candidates.
10214 (Pedantically in the latter case the builtin which matched the user
10215 function should not be added to the overload set, but we spot it here.
10217 [over.match.oper]
10218 ... the builtin candidates include ...
10219 - do not have the same parameter type list as any non-template
10220 non-member candidate. */
10223 {
10229 {
10231 /* Two built-in candidates; arbitrarily pick one. */
10234 /* cand1 is built-in; prefer cand2. */
10236 else
10237 /* cand2 is built-in; prefer cand1. */
10239 }
10240 }
10242 /* For candidates of a multi-versioned function, make the version with
10243 the highest priority win. This version will be checked for dispatching
10244 first. If this version can be inlined into the caller, the front-end
10245 will simply make a direct call to this function. */
10251 {
10257 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10258 is possible that cand1->fn and cand2->fn are function versions but of
10259 different functions. Check types to see if they are versions of the same
10260 function. */
10263 {
10264 /* Always make the version with the higher priority, more
10265 specialized, win. */
10269 else
10271 }
10272 }
10274 /* If the two function declarations represent the same function (this can
10275 happen with declarations in multiple scopes and arg-dependent lookup),
10276 arbitrarily choose one. But first make sure the default args we're
10277 using match. */
10280 {
10287 {
10288 /* Don't crash if the fn is variadic. */
10293 }
10301 {
10304 {
10306 {
10308 {
10310 "default argument mismatch in "
10312 {
10317 }
10318 }
10319 else
10321 }
10322 else
10325 }
10328 }
10331 }
10333 tweak:
10335 /* Extension: If the worst conversion for one candidate is worse than the
10336 worst conversion for the other, take the first. */
10338 {
10343 {
10348 }
10354 {
10355 /* Don't choose a deleted function over ambiguity. */
10359 {
10361 "ISO C++ says that these are ambiguous, even "
10362 "though the worst conversion for the first is better than "
10366 }
10367 else
10370 }
10371 }
10375 }
10377 /* Given a list of candidates for overloading, find the best one, if any.
10378 This algorithm has a worst case of O(2n) (winner is last), and a best
10379 case of O(n/2) (totally ambiguous); much better than a sorting
10380 algorithm. */
10384 {
10389 /* Walk through the list once, comparing each current champ to the next
10390 candidate, knocking out a candidate or two with each comparison. */
10393 {
10397 else
10398 {
10400 {
10405 }
10406 else
10407 {
10410 }
10413 }
10414 }
10416 /* Make sure the champ is better than all the candidates it hasn't yet
10417 been compared to. */
10420 challenger != champ
10423 {
10427 }
10430 }
10432 /* Returns nonzero if things of type FROM can be converted to TO. */
10434 bool
10436 {
10438 /* implicit_conversion only considers user-defined conversions
10439 if it has an expression for the call argument list. */
10443 }
10445 /* Returns nonzero if things of type FROM can be converted to TO with a
10446 standard conversion. */
10448 bool
10450 {
10452 }
10454 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10456 bool
10458 tsubst_flags_t complain)
10459 {
10464 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10466 /* We want to discard any access checks done for this test,
10467 as we might not be in the appropriate access context and
10468 we'll do the check again when we actually perform the
10469 conversion. */
10476 /* Discard the access checks now. */
10478 /* Free all the conversions we allocated. */
10482 }
10484 /* Like can_convert_arg, but allows dubious conversions as well. */
10486 bool
10488 tsubst_flags_t complain)
10489 {
10493 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10495 /* Try to perform the conversion. */
10498 /* Free all the conversions we allocated. */
10502 }
10504 /* Convert EXPR to TYPE. Return the converted expression.
10506 Note that we allow bad conversions here because by the time we get to
10507 this point we are committed to doing the conversion. If we end up
10508 doing a bad conversion, convert_like will complain. */
10510 tree
10513 {
10521 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10529 {
10531 {
10532 /* If expr has unknown type, then it is an overloaded function.
10533 Call instantiate_type to get good error messages. */
10538 else
10541 }
10543 }
10545 {
10546 /* In a template, we are only concerned about determining the
10547 type of non-dependent expressions, so we do not have to
10548 perform the actual conversion. But for initializers, we
10549 need to be able to perform it at instantiation
10550 (or instantiate_non_dependent_expr) time. */
10554 }
10555 else
10558 /* Free all the conversions we allocated. */
10562 }
10564 tree
10566 {
10568 LOOKUP_IMPLICIT);
10569 }
10571 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10572 permitted. If the conversion is valid, the converted expression is
10573 returned. Otherwise, NULL_TREE is returned, except in the case
10574 that TYPE is a class type; in that case, an error is issued. If
10575 C_CAST_P is true, then this direct-initialization is taking
10576 place as part of a static_cast being attempted as part of a C-style
10577 cast. */
10579 tree
10581 tree expr,
10583 tsubst_flags_t complain)
10584 {
10590 /* [dcl.init]
10592 If the destination type is a (possibly cv-qualified) class type:
10594 -- If the initialization is direct-initialization ...,
10595 constructors are considered. ... If no constructor applies, or
10596 the overload resolution is ambiguous, the initialization is
10597 ill-formed. */
10599 {
10605 }
10607 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10611 c_cast_p,
10615 else
10618 c_cast_p,
10619 complain);
10621 /* Free all the conversions we allocated. */
10625 }
10627 /* When initializing a reference that lasts longer than a full-expression,
10628 this special rule applies:
10630 [class.temporary]
10632 The temporary to which the reference is bound or the temporary
10633 that is the complete object to which the reference is bound
10634 persists for the lifetime of the reference.
10636 The temporaries created during the evaluation of the expression
10637 initializing the reference, except the temporary to which the
10638 reference is bound, are destroyed at the end of the
10639 full-expression in which they are created.
10641 In that case, we store the converted expression into a new
10642 VAR_DECL in a new scope.
10644 However, we want to be careful not to create temporaries when
10645 they are not required. For example, given:
10647 struct B {};
10648 struct D : public B {};
10649 D f();
10650 const B& b = f();
10652 there is no need to copy the return value from "f"; we can just
10653 extend its lifetime. Similarly, given:
10655 struct S {};
10656 struct T { operator S(); };
10657 T t;
10658 const S& s = t;
10660 we can extend the lifetime of the return value of the conversion
10661 operator.
10663 The next several functions are involved in this lifetime extension. */
10665 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10666 reference is being bound to a temporary. Create and return a new
10667 VAR_DECL with the indicated TYPE; this variable will store the value to
10668 which the reference is bound. */
10670 tree
10672 {
10675 /* Register the variable. */
10678 {
10679 /* Namespace-scope or local static; give it a mangled name. */
10680 /* FIXME share comdat with decl? */
10691 }
10692 else
10693 /* Create a new cleanup level if necessary. */
10697 }
10699 /* EXPR is the initializer for a variable DECL of reference or
10700 std::initializer_list type. Create, push and return a new VAR_DECL
10701 for the initializer so that it will live as long as DECL. Any
10702 cleanup for the new variable is returned through CLEANUP, and the
10703 code to initialize the new variable is returned through INITP. */
10705 static tree
10708 {
10709 tree init;
10710 tree type;
10711 tree var;
10713 /* Create the temporary variable. */
10717 /* If the rvalue is the result of a function call it will be
10718 a TARGET_EXPR. If it is some other construct (such as a
10719 member access expression where the underlying object is
10720 itself the result of a function call), turn it into a
10721 TARGET_EXPR here. It is important that EXPR be a
10722 TARGET_EXPR below since otherwise the INIT_EXPR will
10723 attempt to make a bitwise copy of EXPR to initialize
10724 VAR. */
10730 {
10734 }
10736 /* Recursively extend temps in this initializer. */
10740 /* Any reference temp has a non-trivial initializer. */
10743 /* If the initializer is constant, put it in DECL_INITIAL so we get
10744 static initialization and use in constant expressions. */
10747 {
10749 {
10750 /* 5.19 says that a constant expression can include an
10751 lvalue-rvalue conversion applied to "a glvalue of literal type
10752 that refers to a non-volatile temporary object initialized
10753 with a constant expression". Rather than try to communicate
10754 that this VAR_DECL is a temporary, just mark it constexpr.
10756 Currently this is only useful for initializer_list temporaries,
10757 since reference vars can't appear in constant expressions. */
10761 }
10764 }
10765 else
10766 /* Create the INIT_EXPR that will initialize the temporary
10767 variable. */
10770 {
10775 else
10776 {
10780 }
10782 /* We must be careful to destroy the temporary only
10783 after its initialization has taken place. If the
10784 initialization throws an exception, then the
10785 destructor should not be run. We cannot simply
10786 transform INIT into something like:
10788 (INIT, ({ CLEANUP_STMT; }))
10790 because emit_local_var always treats the
10791 initializer as a full-expression. Thus, the
10792 destructor would run too early; it would run at the
10793 end of initializing the reference variable, rather
10794 than at the end of the block enclosing the
10795 reference variable.
10797 The solution is to pass back a cleanup expression
10798 which the caller is responsible for attaching to
10799 the statement tree. */
10800 }
10801 else
10802 {
10805 {
10808 tls_aggregates);
10809 else
10811 static_aggregates);
10812 }
10813 else
10814 /* Check whether the dtor is callable. */
10816 }
10817 /* Avoid -Wunused-variable warning (c++/38958). */
10824 }
10826 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10827 initializing a variable of that TYPE. */
10829 tree
10832 {
10840 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10846 {
10848 {
10857 else
10861 }
10863 }
10866 /* Perform the conversion. */
10869 /* We gave an error in build_user_type_conversion_1. */
10871 else
10874 /* Free all the conversions we allocated. */
10878 }
10880 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10881 which is bound either to a reference or a std::initializer_list. */
10883 static tree
10885 {
10890 {
10894 }
10897 /* Deal with binding to a subobject. */
10901 {
10909 }
10911 }
10913 /* INIT is part of the initializer for DECL. If there are any
10914 reference or initializer lists being initialized, extend their
10915 lifetime to match that of DECL. */
10917 tree
10919 {
10925 else
10926 {
10931 {
10933 {
10934 /* The temporary array underlying a std::initializer_list
10935 is handled like a reference temporary. */
10939 }
10940 else
10941 {
10947 }
10951 }
10952 }
10955 }
10957 /* Returns true iff an initializer for TYPE could contain temporaries that
10958 need to be extended because they are bound to references or
10959 std::initializer_list. */
10961 bool
10963 {
10968 {
10975 }
10977 }
10979 /* Returns true iff TYPE is some variant of std::initializer_list. */
10981 bool
10983 {
10988 /* Look through typedefs. */
10993 }
10995 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10996 will accept an argument list of a single std::initializer_list<T>. */
10998 bool
11000 {
11002 tree arg;
11014 /* There are more non-defaulted parms. */
11018 }