| blob | 13269024547b04040a4f004f8f05f696fe10752d |
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 {
2163 /* We don't use build_this here because we don't want to
2164 capture the object argument until we've chosen a
2165 non-static member function. */
2168 }
2169 }
2171 /* Core issue 899: When [copy-]initializing a temporary to be bound
2172 to the first parameter of a copy constructor (12.8) called with
2173 a single argument in the context of direct-initialization,
2174 explicit conversion functions are also considered.
2176 So set LOOKUP_COPY_PARM to let reference_binding know that
2177 it's being called in that context. We generalize the above
2178 to handle move constructors and template constructors as well;
2179 the standardese should soon be updated similarly. */
2183 && (same_type_ignoring_top_level_qualifiers_p
2185 {
2188 /* We allow user-defined conversions within init-lists, but
2189 don't list-initialize the copy parm, as that would mean
2190 using two levels of braces for the same type. */
2194 }
2195 else
2201 }
2202 else
2203 {
2207 }
2214 {
2218 }
2221 {
2224 }
2225 }
2227 out:
2230 }
2232 /* Create an overload candidate for the conversion function FN which will
2233 be invoked for expression OBJ, producing a pointer-to-function which
2234 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2235 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2236 passed on to implicit_conversion.
2238 Actually, we don't really care about FN; we care about the type it
2239 converts to. There may be multiple conversion functions that will
2240 convert to that type, and we rely on build_user_type_conversion_1 to
2241 choose the best one; so when we create our candidate, we record the type
2242 instead of the function. */
2248 tsubst_flags_t complain)
2249 {
2267 /* Don't bother looking up the same type twice. */
2272 {
2278 else
2283 {
2286 /* Leave the 'cand' field null; we'll figure out the conversion in
2287 convert_like_real if this candidate is chosen. */
2289 }
2293 {
2297 }
2298 else
2299 {
2303 }
2310 {
2313 }
2320 }
2324 {
2328 }
2332 }
2334 static void
2338 {
2352 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2353 conversion ops are allowed. We handle that here by just checking for
2354 boolean_type_node because other operators don't ask for it. COND_EXPR
2355 also does contextual conversion to bool for the first operand, but we
2356 handle that in build_conditional_expr, and type1 here is operand 2. */
2361 {
2368 {
2370 /* We need something for printing the candidate. */
2374 }
2376 {
2380 }
2382 }
2384 /* For COND_EXPR we rearranged the arguments; undo that now. */
2386 {
2391 complain);
2394 else
2395 {
2398 boolean_type_node);
2399 }
2400 }
2407 }
2409 static bool
2411 {
2413 }
2415 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2417 static bool
2419 {
2420 /* [over.built]
2422 In this section, the term promoted integral type is used to refer
2423 to those integral types which are preserved by integral promotion
2424 (including e.g. int and long but excluding e.g. char).
2425 Similarly, the term promoted arithmetic type refers to promoted
2426 integral types plus floating types. */
2430 }
2432 /* Create any builtin operator overload candidates for the operator in
2433 question given the converted operand types TYPE1 and TYPE2. The other
2434 args are passed through from add_builtin_candidates to
2435 build_builtin_candidate.
2437 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2438 If CODE is requires candidates operands of the same type of the kind
2439 of which TYPE1 and TYPE2 are, we add both candidates
2440 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2442 static void
2446 tsubst_flags_t complain)
2447 {
2449 {
2457 }
2460 {
2462 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2463 and VQ is either volatile or empty, there exist candidate operator
2464 functions of the form
2465 VQ T& operator++(VQ T&);
2466 T operator++(VQ T&, int);
2467 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2468 type other than bool, and VQ is either volatile or empty, there exist
2469 candidate operator functions of the form
2470 VQ T& operator--(VQ T&);
2471 T operator--(VQ T&, int);
2472 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2473 complete object type, and VQ is either volatile or empty, there exist
2474 candidate operator functions of the form
2475 T*VQ& operator++(T*VQ&);
2476 T*VQ& operator--(T*VQ&);
2477 T* operator++(T*VQ&, int);
2478 T* operator--(T*VQ&, int); */
2484 /* FALLTHRU */
2488 {
2491 }
2494 /* 7 For every cv-qualified or cv-unqualified object type T, there
2495 exist candidate operator functions of the form
2497 T& operator*(T*);
2499 8 For every function type T, there exist candidate operator functions of
2500 the form
2501 T& operator*(T*); */
2510 /* 9 For every type T, there exist candidate operator functions of the form
2511 T* operator+(T*);
2513 10For every promoted arithmetic type T, there exist candidate operator
2514 functions of the form
2515 T operator+(T);
2516 T operator-(T); */
2521 /* FALLTHRU */
2527 /* 11For every promoted integral type T, there exist candidate operator
2528 functions of the form
2529 T operator~(T); */
2536 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2537 is the same type as C2 or is a derived class of C2, T is a complete
2538 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2539 there exist candidate operator functions of the form
2540 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2541 where CV12 is the union of CV1 and CV2. */
2545 {
2553 }
2556 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2557 didate operator functions of the form
2558 LR operator*(L, R);
2559 LR operator/(L, R);
2560 LR operator+(L, R);
2561 LR operator-(L, R);
2562 bool operator<(L, R);
2563 bool operator>(L, R);
2564 bool operator<=(L, R);
2565 bool operator>=(L, R);
2566 bool operator==(L, R);
2567 bool operator!=(L, R);
2568 where LR is the result of the usual arithmetic conversions between
2569 types L and R.
2571 14For every pair of types T and I, where T is a cv-qualified or cv-
2572 unqualified complete object type and I is a promoted integral type,
2573 there exist candidate operator functions of the form
2574 T* operator+(T*, I);
2575 T& operator[](T*, I);
2576 T* operator-(T*, I);
2577 T* operator+(I, T*);
2578 T& operator[](I, T*);
2580 15For every T, where T is a pointer to complete object type, there exist
2581 candidate operator functions of the form112)
2582 ptrdiff_t operator-(T, T);
2584 16For every pointer or enumeration type T, there exist candidate operator
2585 functions of the form
2586 bool operator<(T, T);
2587 bool operator>(T, T);
2588 bool operator<=(T, T);
2589 bool operator>=(T, T);
2590 bool operator==(T, T);
2591 bool operator!=(T, T);
2593 17For every pointer to member type T, there exist candidate operator
2594 functions of the form
2595 bool operator==(T, T);
2596 bool operator!=(T, T); */
2603 {
2606 }
2607 /* FALLTHRU */
2620 {
2623 }
2625 {
2628 }
2629 /* Fall through. */
2645 {
2648 }
2651 {
2654 }
2660 /* FALLTHRU */
2663 {
2666 }
2668 {
2671 }
2674 /* 18For every pair of promoted integral types L and R, there exist candi-
2675 date operator functions of the form
2676 LR operator%(L, R);
2677 LR operator&(L, R);
2678 LR operator^(L, R);
2679 LR operator|(L, R);
2680 L operator<<(L, R);
2681 L operator>>(L, R);
2682 where LR is the result of the usual arithmetic conversions between
2683 types L and R. */
2691 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2695 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2696 type, VQ is either volatile or empty, and R is a promoted arithmetic
2697 type, there exist candidate operator functions of the form
2698 VQ L& operator=(VQ L&, R);
2699 VQ L& operator*=(VQ L&, R);
2700 VQ L& operator/=(VQ L&, R);
2701 VQ L& operator+=(VQ L&, R);
2702 VQ L& operator-=(VQ L&, R);
2704 20For every pair T, VQ), where T is any type and VQ is either volatile
2705 or empty, there exist candidate operator functions of the form
2706 T*VQ& operator=(T*VQ&, T*);
2708 21For every pair T, VQ), where T is a pointer to member type and VQ is
2709 either volatile or empty, there exist candidate operator functions of
2710 the form
2711 VQ T& operator=(VQ T&, T);
2713 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2714 unqualified complete object type, VQ is either volatile or empty, and
2715 I is a promoted integral type, there exist candidate operator func-
2716 tions of the form
2717 T*VQ& operator+=(T*VQ&, I);
2718 T*VQ& operator-=(T*VQ&, I);
2720 23For every triple L, VQ, R), where L is an integral or enumeration
2721 type, VQ is either volatile or empty, and R is a promoted integral
2722 type, there exist candidate operator functions of the form
2724 VQ L& operator%=(VQ L&, R);
2725 VQ L& operator<<=(VQ L&, R);
2726 VQ L& operator>>=(VQ L&, R);
2727 VQ L& operator&=(VQ L&, R);
2728 VQ L& operator^=(VQ L&, R);
2729 VQ L& operator|=(VQ L&, R); */
2733 {
2737 {
2740 }
2741 /* FALLTHRU */
2754 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2767 {
2770 }
2775 }
2780 /* [over.built]
2782 For every pair of promoted arithmetic types L and R, there
2783 exist candidate operator functions of the form
2785 LR operator?(bool, L, R);
2787 where LR is the result of the usual arithmetic conversions
2788 between types L and R.
2790 For every type T, where T is a pointer or pointer-to-member
2791 type, there exist candidate operator functions of the form T
2792 operator?(bool, T, T); */
2796 /* That's OK. */
2799 /* Otherwise, the types should be pointers. */
2803 /* We don't check that the two types are the same; the logic
2804 below will actually create two candidates; one in which both
2805 parameter types are TYPE1, and one in which both parameter
2806 types are TYPE2. */
2817 }
2819 /* Make sure we don't create builtin candidates with dependent types. */
2823 {
2824 /* Try to recover if one of the types is non-dependent. But if
2825 there's only one type, there's nothing we can do. */
2828 /* And we lose if both are dependent. */
2831 /* Or if they have different forms. */
2839 }
2841 /* If we're dealing with two pointer types or two enumeral types,
2842 we need candidates for both of them. */
2851 {
2853 {
2855 error_mark_node,
2856 error_mark_node,
2857 CPO_CONVERSION,
2858 tf_none);
2860 {
2861 build_builtin_candidate
2865 }
2866 }
2868 build_builtin_candidate
2870 build_builtin_candidate
2873 }
2875 build_builtin_candidate
2877 }
2879 tree
2881 {
2887 }
2889 /* There are three conditions of builtin candidates:
2891 1) bool-taking candidates. These are the same regardless of the input.
2892 2) pointer-pair taking candidates. These are generated for each type
2893 one of the input types converts to.
2894 3) arithmetic candidates. According to the standard, we should generate
2895 all of these, but I'm trying not to...
2897 Here we generate a superset of the possible candidates for this particular
2898 case. That is a subset of the full set the standard defines, plus some
2899 other cases which the standard disallows. add_builtin_candidate will
2900 filter out the invalid set. */
2902 static void
2906 {
2910 /* TYPES[i] is the set of possible builtin-operator parameter types
2911 we will consider for the Ith argument. */
2916 {
2919 else
2921 }
2924 {
2925 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2926 and VQ is either volatile or empty, there exist candidate operator
2927 functions of the form
2928 VQ T& operator++(VQ T&); */
2938 /* 24There also exist candidate operator functions of the form
2939 bool operator!(bool);
2940 bool operator&&(bool, bool);
2941 bool operator||(bool, bool); */
2944 build_builtin_candidate
2951 build_builtin_candidate
2969 /* Fall through. */
2973 }
2979 {
2981 ;
2983 {
2984 tree convs;
2992 {
2997 }
3003 {
3016 {
3022 }
3026 }
3027 }
3028 else
3029 {
3034 {
3040 }
3042 }
3043 }
3045 /* Run through the possible parameter types of both arguments,
3046 creating candidates with those parameter types. */
3048 {
3050 tree u;
3054 add_builtin_candidate
3057 else
3058 add_builtin_candidate
3061 }
3065 }
3068 /* If TMPL can be successfully instantiated as indicated by
3069 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3071 TMPL is the template. EXPLICIT_TARGS are any explicit template
3072 arguments. ARGLIST is the arguments provided at the call-site.
3073 This does not change ARGLIST. The RETURN_TYPE is the desired type
3074 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3075 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3076 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3084 tsubst_flags_t complain)
3085 {
3095 tree arg;
3097 tree fn;
3101 /* We don't do deduction on the in-charge parameter, the VTT
3102 parameter or 'this'. */
3104 {
3108 /* We're deducing for a call to the result of a template conversion
3110 else
3112 }
3117 {
3120 else
3122 }
3130 {
3131 /* 12.8/6 says, "A declaration of a constructor for a class X is
3132 ill-formed if its first parameter is of type (optionally cv-qualified)
3133 X and either there are no other parameters or else all other
3134 parameters have default arguments. A member function template is never
3135 instantiated to produce such a constructor signature."
3137 So if we're trying to copy an object of the containing class, don't
3138 consider a template constructor that has a first parameter type that
3139 is just a template parameter, as we would deduce a signature that we
3140 would then reject in the code below. */
3142 {
3147 {
3151 }
3152 }
3153 }
3160 {
3163 }
3167 {
3170 }
3175 args_without_in_chrg,
3176 nargs_without_in_chrg,
3181 {
3182 /* Don't repeat unification later if it already resulted in errors. */
3186 nargs_without_in_chrg,
3188 else
3191 }
3194 {
3197 ctype))
3198 {
3199 /* We're trying to produce a constructor with a prohibited signature,
3200 as discussed above; handle here any cases we didn't catch then,
3201 such as X(X<T>). */
3204 }
3205 }
3208 /* Aha, this is a conversion function. */
3211 else
3216 /* This situation can occur if a member template of a template
3217 class is specialized. Then, instantiate_template might return
3218 an instantiation of the specialization, in which case the
3219 DECL_TI_TEMPLATE field will point at the original
3220 specialization. For example:
3222 template <class T> struct S { template <class U> void f(U);
3223 template <> void f(int) {}; };
3224 S<double> sd;
3225 sd.f(3);
3227 Here, TMPL will be template <class U> S<double>::f(U).
3228 And, instantiate template will give us the specialization
3229 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3230 for this will point at template <class T> template <> S<T>::f(int),
3231 so that we can find the definition. For the purposes of
3232 overload resolution, however, we want the original TMPL. */
3234 else
3239 fail:
3242 }
3251 {
3252 return
3257 }
3259 /* Create an overload candidate for the conversion function template TMPL,
3260 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3261 pointer-to-function which will in turn be called with the argument list
3262 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3263 passed on to implicit_conversion. */
3267 tree obj,
3271 {
3272 /* Making this work broke PR 71117, so until the committee resolves core
3273 issue 2189, let's disable this candidate if there are any viable call
3274 operators. */
3278 return
3282 complain);
3283 }
3285 /* The CANDS are the set of candidates that were considered for
3286 overload resolution. Return the set of viable candidates, or CANDS
3287 if none are viable. If any of the candidates were viable, set
3288 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3289 considered viable only if it is strictly viable. */
3295 {
3301 /* Be strict inside templates, since build_over_call won't actually
3302 do the conversions to get pedwarns. */
3312 {
3316 {
3317 /* Be strict in the presence of a viable candidate. Also if
3318 there are template candidates, so that we get deduction errors
3319 for them instead of silently preferring a bad conversion. */
3322 {
3323 /* Put any spliced near matches back onto the main list so
3324 that we see them if there is no strict match. */
3330 }
3331 }
3334 {
3342 }
3343 else
3345 }
3348 }
3350 static bool
3352 {
3357 }
3359 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3360 words, it is about to become the "this" pointer for a member
3361 function call. Take the address of the object. */
3363 static tree
3365 {
3366 /* In a template, we are only concerned about the type of the
3367 expression, so we can take a shortcut. */
3372 }
3374 /* Returns true iff functions are equivalent. Equivalent functions are
3375 not '==' only if one is a function-local extern function or if
3376 both are extern "C". */
3380 {
3389 }
3391 /* Print information about a candidate being rejected due to INFO. */
3393 static void
3395 {
3400 {
3401 /* Conversion of implicit `this' argument failed. */
3403 /* A bad conversion for 'this' must be discarding cv-quals. */
3406 from);
3407 else
3411 }
3413 {
3418 tf_warning_or_error);
3419 }
3421 /* Conversion of conversion function return value failed. */
3424 else
3427 }
3429 /* Print information about a candidate with WANT parameters and we found
3430 HAVE. */
3432 static void
3434 {
3439 }
3441 /* Print information about one overload candidate CANDIDATE. MSGSTR
3442 is the text to print before the candidate itself.
3444 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3445 to have been run through gettext by the caller. This wart makes
3446 life simpler in print_z_candidates and for the translators. */
3448 static void
3451 {
3461 {
3472 else
3475 }
3482 else
3485 {
3488 }
3489 /* Give the user some information about why this candidate failed. */
3491 {
3495 {
3508 "cannot be converted to %qT with a qualification "
3514 "conversion function specialization to %qT is not an "
3519 /* We use template_unification_error_rejection if unification caused
3520 actual non-SFINAE errors, in which case we don't need to repeat
3521 them here. */
3523 {
3527 }
3528 /* Re-run template unification with diagnostics. */
3532 (make_tree_vec
3543 " a constructor taking a single argument of its own "
3547 {
3551 }
3555 "initialization from an expression of the same or derived "
3560 /* This candidate didn't have any issues or we failed to
3561 handle a particular code. Either way... */
3563 }
3564 }
3565 }
3567 static void
3569 {
3576 /* Remove non-viable deleted candidates. */
3579 {
3584 else
3586 }
3587 /* ...if there are any non-deleted ones. */
3591 /* There may be duplicates in the set of candidates. We put off
3592 checking this condition as long as possible, since we have no way
3593 to eliminate duplicates from a set of functions in less than n^2
3594 time. Now we are about to emit an error message, so it is more
3595 permissible to go slowly. */
3597 {
3599 /* Skip builtin candidates and conversion functions. */
3604 {
3608 else
3610 }
3611 }
3615 }
3617 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3618 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3619 the result of the conversion function to convert it to the final
3620 desired type. Merge the two sequences into a single sequence,
3621 and return the merged sequence. */
3625 {
3631 /* Find the end of the second conversion sequence. */
3633 {
3634 /* The entire sequence is a user-conversion sequence. */
3638 }
3640 /* Replace the identity conversion with the user conversion
3641 sequence. */
3645 }
3647 /* Handle overload resolution for initializing an object of class type from
3648 an initializer list. First we look for a suitable constructor that
3649 takes a std::initializer_list; if we don't find one, we then look for a
3650 non-list constructor.
3652 Parameters are as for add_candidates, except that the arguments are in
3653 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3654 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3656 static void
3663 tsubst_flags_t complain)
3664 {
3667 /* We're looking for a ctor for list-initialization. */
3669 /* And we don't allow narrowing conversions. We also use this flag to
3670 avoid the copy constructor call for copy-list-initialization. */
3676 /* Always use the default constructor if the list is empty (DR 990). */
3679 ;
3680 /* If the class has a list ctor, try passing the list as a single
3681 argument first, but only consider list ctors. */
3683 {
3690 }
3692 /* Expand the CONSTRUCTOR into a new argument vec. */
3700 /* We aren't looking for list-ctors anymore. */
3702 /* We allow more user-defined conversions within an init-list. */
3708 }
3710 /* Returns the best overload candidate to perform the requested
3711 conversion. This function is used for three the overloading situations
3712 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3713 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3714 per [dcl.init.ref], so we ignore temporary bindings. */
3718 tsubst_flags_t complain)
3719 {
3721 tree fromtype;
3735 /* We represent conversion within a hierarchy using RVALUE_CONV and
3736 BASE_CONV, as specified by [over.best.ics]; these become plain
3737 constructor calls, as specified in [dcl.init]. */
3742 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3743 creating a garbage BASELINK; constructors can't be inherited. */
3746 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3747 a single element. For now, let's handle constructors as before and also
3748 consider conversion operators from the element. */
3755 {
3760 {
3761 /* [class.conv.fct] A conversion function is never used to
3762 convert a (possibly cv-qualified) object to the (possibly
3763 cv-qualified) same object type (or a reference to it), to a
3764 (possibly cv-qualified) base class of that type (or a
3765 reference to it)... */
3766 }
3767 else
3769 }
3776 /* It's OK to bind a temporary for converting constructor arguments, but
3777 not in converting the return value of a conversion operator. */
3783 {
3788 /* We should never try to call the abstract or base constructor
3789 from here. */
3795 {
3796 /* List-initialization. */
3800 }
3801 else
3802 {
3806 }
3809 {
3812 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3813 set, then this is copy-initialization. In that case, "The
3814 result of the call is then used to direct-initialize the
3815 object that is the destination of the copy-initialization."
3816 [dcl.init]
3818 We represent this in the conversion sequence with an
3819 rvalue conversion, which means a constructor call. */
3822 cand->second_conv
3824 }
3825 }
3828 {
3830 /* FIXME see above about C++17. */
3832 else
3834 }
3837 {
3841 /* If we are called to convert to a reference type, we are trying to
3842 find a direct binding, so don't even consider temporaries. If
3843 we don't find a direct binding, the caller will try again to
3844 look for a temporary binding. */
3855 {
3857 conversion *ics
3859 rettype,
3862 complain);
3864 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3865 copy-initialization. In that case, "The result of the
3866 call is then used to direct-initialize the object that is
3867 the destination of the copy-initialization." [dcl.init]
3869 We represent this in the conversion sequence with an
3870 rvalue conversion, which means a constructor call. But
3871 don't add a second rvalue conversion if there's already
3872 one there. Which there really shouldn't be, but it's
3873 harmless since we'd add it here anyway. */
3881 {
3885 }
3888 {
3889 /* 13.3.1.5: For direct-initialization, those explicit
3890 conversion functions that are not hidden within S and
3891 yield type T or a type that can be converted to type T
3892 with a qualification conversion (4.4) are also candidate
3893 functions. */
3894 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3895 I've raised this issue with the committee. --jason 9/2011 */
3898 }
3900 {
3902 cand->reason
3905 }
3908 {
3909 /* 13.3.3.1.2: If the user-defined conversion is specified by
3910 a specialization of a conversion function template, the
3911 second standard conversion sequence shall have exact match
3912 rank. */
3915 }
3916 }
3917 }
3921 {
3925 }
3929 {
3931 {
3935 }
3942 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3943 ambiguous conversion is no worse than another user-defined
3944 conversion. */
3947 }
3949 tree convtype;
3953 /* DR 5: [in the first step of copy-initialization]...if the function
3954 is a constructor, the call initializes a temporary of the
3955 cv-unqualified version of the destination type. */
3957 else
3959 /* Build the user conversion sequence. */
3960 conv = build_conv
3962 convtype,
3968 /* Remember that this was a list-initialization. */
3972 /* Combine it with the second conversion sequence. */
3977 }
3979 /* Wrapper for above. */
3981 tree
3983 tsubst_flags_t complain)
3984 {
3986 tree ret;
3992 {
3995 else
3996 {
3999 }
4000 }
4001 else
4006 }
4008 /* Subroutine of convert_nontype_argument.
4010 EXPR is an expression used in a context that requires a converted
4011 constant-expression, such as a template non-type parameter. Do any
4012 necessary conversions (that are permitted for converted
4013 constant-expressions) to convert it to the desired type.
4015 If conversion is successful, returns the converted expression;
4016 otherwise, returns error_mark_node. */
4018 tree
4020 {
4023 tree t;
4029 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4036 /* A converted constant expression of type T is an expression, implicitly
4037 converted to type T, where the converted expression is a constant
4038 expression and the implicit conversion sequence contains only
4040 * user-defined conversions,
4041 * lvalue-to-rvalue conversions (7.1),
4042 * array-to-pointer conversions (7.2),
4043 * function-to-pointer conversions (7.3),
4044 * qualification conversions (7.5),
4045 * integral promotions (7.6),
4046 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4047 * null pointer conversions (7.11) from std::nullptr_t,
4048 * null member pointer conversions (7.12) from std::nullptr_t, and
4049 * function pointer conversions (7.13),
4051 and where the reference binding (if any) binds directly. */
4056 {
4058 {
4059 /* A conversion function is OK. If it isn't constexpr, we'll
4060 complain later that the argument isn't constant. */
4062 /* The lvalue-to-rvalue conversion is OK. */
4064 /* Array-to-pointer and function-to-pointer. */
4066 /* Function pointer conversions. */
4068 /* Qualification conversions. */
4074 {
4080 }
4090 /* Integral promotion or conversion. */
4093 /* Conversion from nullptr to pointer or pointer-to-member. */
4099 /* fall through. */
4104 }
4105 }
4107 /* Avoid confusing convert_nontype_argument by introducing
4108 a redundant conversion to the same reference type. */
4111 {
4115 }
4119 else
4122 /* Free all the conversions we allocated. */
4126 }
4128 /* Do any initial processing on the arguments to a function call. */
4132 {
4134 tree arg;
4137 {
4141 {
4145 }
4148 }
4150 }
4152 /* Perform overload resolution on FN, which is called with the ARGS.
4154 Return the candidate function selected by overload resolution, or
4155 NULL if the event that overload resolution failed. In the case
4156 that overload resolution fails, *CANDIDATES will be the set of
4157 candidates considered, and ANY_VIABLE_P will be set to true or
4158 false to indicate whether or not any of the candidates were
4159 viable.
4161 The ARGS should already have gone through RESOLVE_ARGS before this
4162 function is called. */
4169 {
4171 tree explicit_targs;
4182 /* Check FN. */
4189 {
4193 }
4195 /* Add the various candidate functions. */
4200 LOOKUP_NORMAL,
4206 else
4211 }
4213 /* Print an error message about being unable to build a call to FN with
4214 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4215 be located; CANDIDATES is a possibly empty list of such
4216 functions. */
4218 static void
4221 {
4224 {
4227 }
4236 else
4241 }
4243 /* Return an expression for a call to FN (a namespace-scope function,
4244 or a static member function) with the ARGS. This may change
4245 ARGS. */
4247 tree
4249 tsubst_flags_t complain)
4250 {
4254 tree result;
4257 {
4261 }
4266 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4270 complain);
4273 {
4275 {
4276 // If there is a single (non-viable) function candidate,
4277 // let the error be diagnosed by cp_build_function_call_vec.
4282 // Otherwise, emit notes for non-viable candidates.
4284 }
4286 }
4287 else
4288 {
4290 /* If fn is template_id_expr, the call has explicit template arguments
4291 (e.g. func<int>(5)), communicate this info to build_over_call
4292 through flags so that later we can use it to decide whether to warn
4293 about peculiar null pointer conversion. */
4295 {
4296 /* If overload resolution selects a specialization of a
4297 function concept for non-dependent template arguments,
4298 the expression is true if the constraints are satisfied
4299 and false otherwise.
4301 NOTE: This is an extension of Concepts Lite TS that
4302 allows constraints to be used in expressions. */
4304 {
4310 }
4313 }
4316 }
4318 /* Free all the conversions we allocated. */
4322 }
4324 /* Build a call to a global operator new. FNNAME is the name of the
4325 operator (either "operator new" or "operator new[]") and ARGS are
4326 the arguments provided. This may change ARGS. *SIZE points to the
4327 total number of bytes required by the allocation, and is updated if
4328 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4329 be used. If this function determines that no cookie should be
4330 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4331 is not NULL_TREE, it is evaluated before calculating the final
4332 array size, and if it fails, the array size is replaced with
4333 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4334 is non-NULL, it will be set, upon return, to the allocation
4335 function called. */
4337 tree
4342 {
4344 tree fns;
4351 /* Set to (size_t)-1 if the size check fails. */
4353 {
4359 }
4365 /* Based on:
4367 [expr.new]
4369 If this lookup fails to find the name, or if the allocated type
4370 is not a class type, the allocation function's name is looked
4371 up in the global scope.
4373 we disregard block-scope declarations of "operator new". */
4378 {
4383 /* If no aligned allocation function matches, try again without the
4384 alignment. */
4385 }
4387 /* Figure out what function is being called. */
4390 complain);
4392 /* If no suitable function could be found, issue an error message
4393 and give up. */
4395 {
4399 }
4401 /* If a cookie is required, add some extra space. Whether
4402 or not a cookie is required cannot be determined until
4403 after we know which function was called. */
4405 {
4407 tree arg_types;
4410 /* Skip the size_t parameter. */
4412 /* Check the remaining parameters (if any). */
4416 ptr_type_node))
4418 /* If we need a cookie, adjust the number of bytes allocated. */
4420 {
4421 /* Update the total size. */
4424 {
4425 /* Set to (size_t)-1 if the size check fails. */
4429 }
4430 /* Update the argument list to reflect the adjusted size. */
4432 }
4433 else
4435 }
4437 /* Tell our caller which function we decided to call. */
4441 /* Build the CALL_EXPR. */
4443 }
4445 /* Build a new call to operator(). This may change ARGS. */
4447 static tree
4449 {
4466 {
4468 /* It's no good looking for an overloaded operator() on a
4469 pointer-to-member-function. */
4473 }
4476 {
4480 }
4481 else
4485 {
4489 }
4491 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4495 {
4503 }
4508 {
4516 {
4523 add_template_conv_candidate
4527 else
4531 }
4532 }
4534 /* Be strict here because if we choose a bad conversion candidate, the
4535 errors we get won't mention the call context. */
4538 {
4540 {
4544 }
4546 }
4547 else
4548 {
4551 {
4553 {
4557 }
4559 }
4560 /* Since cand->fn will be a type, not a function, for a conversion
4561 function, we must be careful not to unconditionally look at
4562 DECL_NAME here. */
4566 else
4567 {
4571 else
4575 }
4576 }
4578 /* Free all the conversions we allocated. */
4582 }
4584 /* Wrapper for above. */
4586 tree
4588 {
4589 tree ret;
4594 }
4596 /* Called by op_error to prepare format strings suitable for the error
4597 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4598 and a suffix (controlled by NTYPES). */
4602 {
4612 else
4616 }
4618 static void
4621 {
4626 else
4630 {
4636 else
4648 else
4658 else
4669 else
4679 else
4684 else
4688 else
4693 }
4694 }
4696 /* Return the implicit conversion sequence that could be used to
4697 convert E1 to E2 in [expr.cond]. */
4701 {
4707 /* [expr.cond]
4709 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4710 implicitly converted (clause _conv_) to the type "lvalue reference to
4711 T2", subject to the constraint that in the conversion the
4712 reference must bind directly (_dcl.init.ref_) to an lvalue.
4714 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4715 implicitly converted to the type "rvalue reference to T2", subject to
4716 the constraint that the reference must bind directly. */
4718 {
4721 t1,
4722 e1,
4724 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4726 complain);
4729 }
4731 /* If E2 is a prvalue or if neither of the conversions above can be done
4732 and at least one of the operands has (possibly cv-qualified) class
4733 type: */
4737 /* [expr.cond]
4739 If E1 and E2 have class type, and the underlying class types are
4740 the same or one is a base class of the other: E1 can be converted
4741 to match E2 if the class of T2 is the same type as, or a base
4742 class of, the class of T1, and the cv-qualification of T2 is the
4743 same cv-qualification as, or a greater cv-qualification than, the
4744 cv-qualification of T1. If the conversion is applied, E1 is
4745 changed to an rvalue of type T2 that still refers to the original
4746 source class object (or the appropriate subobject thereof). */
4749 {
4751 {
4756 else
4759 }
4760 else
4762 }
4763 else
4764 /* [expr.cond]
4766 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4767 converted to the type that expression E2 would have if E2 were
4768 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4771 }
4773 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4774 arguments to the conditional expression. */
4776 static tree
4778 tsubst_flags_t complain)
4779 {
4780 tree arg2_type;
4781 tree arg3_type;
4790 /* As a G++ extension, the second argument to the conditional can be
4791 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4792 c'.) If the second operand is omitted, make sure it is
4793 calculated only once. */
4795 {
4803 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4806 else
4808 }
4810 /* If something has already gone wrong, just pass that fact up the
4811 tree. */
4821 {
4824 /* If arg1 is another cond_expr choosing between -1 and 0,
4825 then we can use its comparison. It may help to avoid
4826 additional comparison, produce more accurate diagnostics
4827 and enables folding. */
4837 /* force_rvalue can return error_mark on valid arguments. */
4848 {
4849 /* Rely on the error messages of the scalar version. */
4858 {
4866 }
4870 /* We could pass complain & tf_warning to unsafe_conversion_p,
4871 but the warnings (like Wsign-conversion) have already been
4872 given by the scalar build_conditional_expr_1. We still check
4873 unsafe_conversion_p to forbid truncating long long -> float. */
4875 {
4880 }
4882 {
4887 }
4897 }
4900 {
4906 {
4910 {
4916 }
4918 {
4924 }
4927 }
4928 }
4934 {
4937 "incompatible vector types in conditional expression: "
4941 }
4944 {
4947 }
4949 }
4951 /* [expr.cond]
4953 The first expression is implicitly converted to bool (clause
4954 _conv_). */
4956 LOOKUP_NORMAL);
4960 /* [expr.cond]
4962 If either the second or the third operand has type (possibly
4963 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4964 array-to-pointer (_conv.array_), and function-to-pointer
4965 (_conv.func_) standard conversions are performed on the second
4966 and third operands. */
4970 {
4971 /* Do the conversions. We don't these for `void' type arguments
4972 since it can't have any effect and since decay_conversion
4973 does not handle that case gracefully. */
4981 /* [expr.cond]
4983 One of the following shall hold:
4985 --The second or the third operand (but not both) is a
4986 throw-expression (_except.throw_); the result is of the
4987 type of the other and is an rvalue.
4989 --Both the second and the third operands have type void; the
4990 result is of type void and is an rvalue.
4992 We must avoid calling force_rvalue for expressions of type
4993 "void" because it will complain that their value is being
4994 used. */
4997 {
4999 {
5003 }
5006 }
5009 {
5011 {
5015 }
5018 }
5021 else
5022 {
5024 {
5027 "second operand to the conditional operator "
5028 "is of type %<void%>, but the third operand is "
5030 else
5032 "third operand to the conditional operator "
5033 "is of type %<void%>, but the second operand is "
5035 }
5037 }
5041 }
5042 /* [expr.cond]
5044 Otherwise, if the second and third operand have different types,
5045 and either has (possibly cv-qualified) class type, or if both are
5046 glvalues of the same value category and the same type except for
5047 cv-qualification, an attempt is made to convert each of those operands
5048 to the type of the other. */
5052 arg3_type)
5055 {
5060 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5066 /* [expr.cond]
5068 If both can be converted, or one can be converted but the
5069 conversion is ambiguous, the program is ill-formed. If
5070 neither can be converted, the operands are left unchanged and
5071 further checking is performed as described below. If exactly
5072 one conversion is possible, that conversion is applied to the
5073 chosen operand and the converted operand is used in place of
5074 the original operand for the remainder of this section. */
5079 {
5081 {
5088 else
5090 }
5092 }
5094 {
5098 /* Even if CONV2 is a valid conversion, the result of the
5099 conversion may be invalid. For example, if ARG3 has type
5100 "volatile X", and X does not have a copy constructor
5101 accepting a "volatile X&", then even if ARG2 can be
5102 converted to X, the conversion will fail. */
5106 }
5108 {
5115 }
5117 /* Free all the conversions we allocated. */
5123 /* If, after the conversion, both operands have class type,
5124 treat the cv-qualification of both operands as if it were the
5125 union of the cv-qualification of the operands.
5127 The standard is not clear about what to do in this
5128 circumstance. For example, if the first operand has type
5129 "const X" and the second operand has a user-defined
5130 conversion to "volatile X", what is the type of the second
5131 operand after this step? Making it be "const X" (matching
5132 the first operand) seems wrong, as that discards the
5133 qualification without actually performing a copy. Leaving it
5134 as "volatile X" seems wrong as that will result in the
5135 conditional expression failing altogether, even though,
5136 according to this step, the one operand could be converted to
5137 the type of the other. */
5145 }
5147 /* [expr.cond]
5149 If the second and third operands are glvalues of the same value
5150 category and have the same type, the result is of that type and
5151 value category. */
5155 {
5160 }
5162 /* [expr.cond]
5164 Otherwise, the result is an rvalue. If the second and third
5165 operand do not have the same type, and either has (possibly
5166 cv-qualified) class type, overload resolution is used to
5167 determine the conversions (if any) to be applied to the operands
5168 (_over.match.oper_, _over.built_). */
5172 {
5177 /* Rearrange the arguments so that add_builtin_candidate only has
5178 to know about two args. In build_builtin_candidate, the
5179 arguments are unscrambled. */
5184 COND_EXPR,
5185 NOP_EXPR,
5187 args,
5190 /* [expr.cond]
5192 If the overload resolution fails, the program is
5193 ill-formed. */
5196 {
5201 }
5204 {
5206 {
5209 }
5211 }
5213 /* [expr.cond]
5215 Otherwise, the conversions thus determined are applied, and
5216 the converted operands are used in place of the original
5217 operands for the remainder of this section. */
5226 }
5228 /* [expr.cond]
5230 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5231 and function-to-pointer (_conv.func_) standard conversions are
5232 performed on the second and third operands.
5234 We need to force the lvalue-to-rvalue conversion here for class types,
5235 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5236 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5237 regions. */
5250 /* [expr.cond]
5252 After those conversions, one of the following shall hold:
5254 --The second and third operands have the same type; the result is of
5255 that type. */
5258 /* [expr.cond]
5260 --The second and third operands have arithmetic or enumeration
5261 type; the usual arithmetic conversions are performed to bring
5262 them to a common type, and the result is of that type. */
5267 {
5268 /* In this case, there is always a common type. */
5270 arg3_type);
5273 "implicit conversion from %qH to %qI to "
5275 loc);
5279 {
5283 /* Two enumerators from the same enumeration can have different
5289 }
5296 {
5300 }
5304 }
5305 /* [expr.cond]
5307 --The second and third operands have pointer type, or one has
5308 pointer type and the other is a null pointer constant; pointer
5309 conversions (_conv.ptr_) and qualification conversions
5310 (_conv.qual_) are performed to bring them to their composite
5311 pointer type (_expr.rel_). The result is of the composite
5312 pointer type.
5314 --The second and third operands have pointer to member type, or
5315 one has pointer to member type and the other is a null pointer
5316 constant; pointer to member conversions (_conv.mem_) and
5317 qualification conversions (_conv.qual_) are performed to bring
5318 them to a common type, whose cv-qualification shall match the
5319 cv-qualification of either the second or the third operand.
5320 The result is of the common type. */
5328 {
5331 complain);
5336 }
5339 {
5344 }
5349 valid_operands:
5352 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5353 warn here, because the COND_EXPR will be turned into ARG2. */
5359 /* We can't use result_type below, as fold might have returned a
5360 throw_expr. */
5363 {
5364 /* Expand both sides into the same slot, hopefully the target of
5365 the ?: expression. We used to check for TARGET_EXPRs here,
5366 but now we sometimes wrap them in NOP_EXPRs so the test would
5367 fail. */
5370 /* If this expression is an rvalue, but might be mistaken for an
5371 lvalue, we must add a NON_LVALUE_EXPR. */
5373 }
5374 else
5378 }
5380 /* Wrapper for above. */
5382 tree
5384 tsubst_flags_t complain)
5385 {
5386 tree ret;
5391 }
5393 /* OPERAND is an operand to an expression. Perform necessary steps
5394 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5395 returned. */
5397 static tree
5399 {
5401 {
5404 /* Make sure the template type is instantiated now. */
5406 }
5409 }
5411 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5412 OVERLOAD) to the CANDIDATES, returning an updated list of
5413 CANDIDATES. The ARGS are the arguments provided to the call;
5414 if FIRST_ARG is non-null it is the implicit object argument,
5415 otherwise the first element of ARGS is used if needed. The
5416 EXPLICIT_TARGS are explicit template arguments provided.
5417 TEMPLATE_ONLY is true if only template functions should be
5418 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5419 add_function_candidate. */
5421 static void
5423 tree return_type,
5428 tsubst_flags_t complain)
5429 {
5430 tree ctype;
5434 unification_kind_t strict;
5439 /* Precalculate special handling of constructors and conversion ops. */
5442 {
5446 /* We're doing return_type(x). */
5448 else
5449 /* We're doing x.operator return_type(). */
5451 /* [over.match.funcs] For conversion functions, the function
5452 is considered to be a member of the class of the implicit
5453 object argument for the purpose of defining the type of
5454 the implicit object parameter. */
5456 }
5457 else
5458 {
5460 {
5462 /* For list-initialization we consider explicit constructors
5463 and complain if one is chosen. */
5464 check_converting
5467 }
5470 }
5474 else
5475 /* Delay creating the implicit this parameter until it is needed. */
5479 {
5491 {
5492 /* Figure out where the object arg comes from. If this
5493 function is a non-static member and we didn't get an
5494 implicit object argument, move it out of args. */
5496 {
5498 tree arg;
5505 }
5509 }
5513 fn,
5514 ctype,
5515 explicit_targs,
5516 fn_first_arg,
5517 fn_args,
5518 return_type,
5519 access_path,
5520 conversion_path,
5521 flags,
5522 strict,
5523 complain);
5526 fn,
5527 ctype,
5528 fn_first_arg,
5529 fn_args,
5530 access_path,
5531 conversion_path,
5532 flags,
5533 complain);
5534 }
5535 }
5537 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5538 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5540 static int
5542 {
5544 {
5545 // 5. b @= a
5549 // 6. a[b]
5553 // 1. a.b
5554 // Not overloadable (yet).
5555 // 2. a->b
5556 // Only one argument.
5557 // 3. a->*b
5559 // 7. a << b
5561 // 8. a >> b
5567 }
5568 }
5570 static tree
5573 {
5576 tree fnname;
5594 {
5598 }
5599 else
5606 {
5611 /* Use build_op_new_call and build_op_delete_call instead. */
5615 /* Use build_op_call instead. */
5622 /* These are saved for the sake of warn_logical_operator. */
5632 /* These are saved for the sake of maybe_warn_bool_compare. */
5637 /* =, ->, [], () must be non-static member functions. */
5641 /* FALLTHRU */
5649 }
5655 /* Use build_conditional_expr instead. */
5671 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5674 /* Add namespace-scope operators to the list of functions to
5675 consider. */
5677 {
5683 }
5689 /* Add class-member operators to the candidate set. */
5691 {
5692 tree fns;
5696 {
5699 }
5707 }
5708 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5709 only non-member functions that have type T1 or reference to
5710 cv-qualified-opt T1 for the first argument, if the first argument
5711 has an enumeration type, or T2 or reference to cv-qualified-opt
5712 T2 for the second argument, if the second argument has an
5713 enumeration type. Filter out those that don't match. */
5715 {
5719 {
5729 {
5735 && (same_type_ignoring_top_level_qualifiers_p
5740 }
5742 /* No argument has an appropriate type, so remove this
5743 candidate function from the list. */
5745 {
5748 }
5749 }
5750 }
5756 {
5759 /* For these, the built-in candidates set is empty
5760 [over.match.oper]/3. We don't want non-strict matches
5761 because exact matches are always possible with built-in
5762 operators. The built-in candidate set for COMPONENT_REF
5763 would be empty too, but since there are no such built-in
5764 operators, we accept non-strict matches for them. */
5771 }
5775 {
5777 {
5780 /* Don't try anything fancy if we're not allowed to produce
5781 errors. */
5785 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5786 distinguish between prefix and postfix ++ and
5787 operator++() was used for both, so we allow this with
5788 -fpermissive. */
5789 else
5790 {
5796 }
5803 else
5809 /* The caller will deal with these. */
5819 {
5820 /* If one of the arguments of the operator represents
5821 an invalid use of member function pointer, try to report
5822 a meaningful error ... */
5827 else
5828 {
5829 /* ... Otherwise, report the more generic
5830 "no matching operator found" error */
5833 }
5834 }
5837 }
5838 }
5839 else
5840 {
5843 {
5845 {
5848 }
5850 }
5852 {
5858 else
5864 {
5869 /* This prevents build_new_function_call from discarding this
5870 function during instantiation of the enclosing template. */
5873 /* Specify evaluation order as per P0145R2. */
5876 {
5887 }
5888 }
5889 }
5890 else
5891 {
5892 /* Give any warnings we noticed during overload resolution. */
5894 {
5898 }
5900 /* Check for comparison of different enum types. */
5902 {
5914 {
5918 }
5922 }
5924 /* We need to strip any leading REF_BIND so that bitfields
5925 don't cause errors. This should not remove any important
5926 conversions, because builtins don't apply to class
5927 objects directly. */
5934 {
5938 else
5941 /* We need to call warn_logical_operator before
5942 converting arg2 to a boolean_type, but after
5943 decaying an enumerator to its value. */
5950 }
5952 {
5957 }
5959 }
5960 }
5962 user_defined_result_ready:
5964 /* Free all the conversions we allocated. */
5970 builtin:
5972 {
5987 /* Fall through. */
6000 /* Fall through. */
6033 complain),
6036 /* The caller will deal with these. */
6044 }
6046 }
6048 /* Wrapper for above. */
6050 tree
6054 {
6055 tree ret;
6061 }
6063 /* CALL was returned by some call-building function; extract the actual
6064 CALL_EXPR from any bits that have been tacked on, e.g. by
6065 convert_from_reference. */
6067 tree
6069 {
6080 }
6082 /* Returns true if FN has two parameters, of which the second has type
6083 size_t. */
6085 static bool
6087 {
6099 }
6101 /* True if T, an allocation function, has std::align_val_t as its second
6102 argument. */
6104 bool
6106 {
6112 }
6114 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6115 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6116 std::align_val_t. */
6118 static bool
6120 {
6124 /* A template instance is never a usual deallocation function,
6125 regardless of its signature. */
6141 }
6143 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6144 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6146 bool
6148 {
6149 /* A template instance is never a usual deallocation function,
6150 regardless of its signature. */
6155 /* If a class T has a member deallocation function named operator delete
6156 with exactly one parameter, then that function is a usual
6157 (non-placement) deallocation function. If class T does not declare
6158 such an operator delete but does declare a member deallocation
6159 function named operator delete with exactly two parameters, the second
6160 of which has type std::size_t (18.2), then this function is a usual
6161 deallocation function. */
6173 }
6175 /* Build a call to operator delete. This has to be handled very specially,
6176 because the restrictions on what signatures match are different from all
6177 other call instances. For a normal delete, only a delete taking (void *)
6178 or (void *, size_t) is accepted. For a placement delete, only an exact
6179 match with the placement new is accepted.
6181 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6182 ADDR is the pointer to be deleted.
6183 SIZE is the size of the memory block to be deleted.
6184 GLOBAL_P is true if the delete-expression should not consider
6185 class-specific delete operators.
6186 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6188 If this call to "operator delete" is being generated as part to
6189 deallocate memory allocated via a new-expression (as per [expr.new]
6190 which requires that if the initialization throws an exception then
6191 we call a deallocation function), then ALLOC_FN is the allocation
6192 function. */
6194 tree
6198 {
6212 /* In [class.free]
6214 If the result of the lookup is ambiguous or inaccessible, or if
6215 the lookup selects a placement deallocation function, the
6216 program is ill-formed.
6218 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6219 {
6223 }
6224 else
6230 /* Strip const and volatile from addr. */
6234 {
6235 /* "A declaration of a placement deallocation function matches the
6236 declaration of a placement allocation function if it has the same
6237 number of parameters and, after parameter transformations (8.3.5),
6238 all parameter types except the first are identical."
6240 So we build up the function type we want and ask instantiate_type
6241 to get it for us. */
6252 /* "If the lookup finds the two-parameter form of a usual deallocation
6253 function (3.7.4.2) and that function, considered as a placement
6254 deallocation function, would have been selected as a match for the
6255 allocation function, the program is ill-formed." */
6257 {
6265 /* But if the class has an operator delete (void *), then that is
6266 the usual deallocation function, so we shouldn't complain
6267 about using the operator delete (void *, size_t). */
6271 {
6276 }
6277 /* Before C++14 a two-parameter global deallocation function is
6278 always a placement deallocation function, but warn if
6279 -Wc++14-compat. */
6281 {
6286 }
6289 {
6291 {
6292 /* Only mention C++14 for namespace-scope delete. */
6295 else
6297 "%qD is a usual (non-placement) deallocation "
6299 }
6300 }
6301 else
6303 ok:;
6304 }
6305 }
6306 else
6307 /* "Any non-placement deallocation function matches a non-placement
6308 allocation function. If the lookup finds a single matching
6309 deallocation function, that function will be called; otherwise, no
6310 deallocation function will be called." */
6312 {
6315 {
6317 {
6320 }
6322 /* -- If the type has new-extended alignment, a function with a
6323 parameter of type std::align_val_t is preferred; otherwise a
6324 function without such a parameter is preferred. If exactly one
6325 preferred function is found, that function is selected and the
6326 selection process terminates. If more than one preferred
6327 function is found, all non-preferred functions are eliminated
6328 from further consideration. */
6330 {
6336 {
6340 }
6341 }
6343 /* -- If the deallocation functions have class scope, the one
6344 without a parameter of type std::size_t is selected. */
6349 /* -- If the type is complete and if, for the second alternative
6350 (delete array) only, the operand is a pointer to a class type
6351 with a non-trivial destructor or a (possibly multi-dimensional)
6352 array thereof, the function with a parameter of type std::size_t
6353 is selected.
6355 -- Otherwise, it is unspecified whether a deallocation function
6356 with a parameter of type std::size_t is selected. */
6357 else
6358 {
6362 /* We need a cookie to determine the array size. */
6364 }
6370 }
6371 }
6373 /* If we have a matching function, call it. */
6375 {
6378 /* If the FN is a member function, make sure that it is
6379 accessible. */
6382 complain);
6384 /* Core issue 901: It's ok to new a type with deleted delete. */
6389 {
6390 /* The placement args might not be suitable for overload
6391 resolution at this point, so build the call directly. */
6401 }
6402 else
6403 {
6404 tree ret;
6410 {
6413 }
6417 }
6418 }
6420 /* [expr.new]
6422 If no unambiguous matching deallocation function can be found,
6423 propagating the exception does not cause the object's memory to
6424 be freed. */
6426 {
6430 alloc_fn);
6432 }
6438 }
6440 /* If the current scope isn't allowed to access DECL along
6441 BASETYPE_PATH, give an error. The most derived class in
6442 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6443 the declaration to use in the error diagnostic. */
6445 bool
6448 {
6453 {
6454 /* 7.3.3/18: The additional constructors are accessible if they would be
6455 accessible when used to construct an object of the corresponding base
6456 class. */
6460 }
6463 {
6465 {
6469 {
6475 }
6477 {
6483 }
6484 else
6485 {
6490 }
6491 }
6493 }
6496 }
6498 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6499 bitwise or of LOOKUP_* values. If any errors are warnings are
6500 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6501 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6502 to NULL. */
6504 static tree
6507 {
6513 /* If the source is a packed field, calling the copy constructor will require
6514 binding the field to the reference parameter to the copy constructor, and
6515 we'll end up with an infinite loop. If we can use a bitwise copy, then
6516 do that now. */
6532 }
6534 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6535 EXPR is implicitly converted to type TOTYPE.
6536 FN and ARGNUM are used for diagnostics. */
6538 static void
6540 {
6541 /* Issue warnings about peculiar, but valid, uses of NULL. */
6544 {
6545 source_location loc =
6552 else
6555 }
6557 /* Issue warnings if "false" is converted to a NULL pointer */
6560 {
6563 "converting %<false%> to pointer type for argument %P "
6565 else
6568 }
6569 }
6571 /* We gave a diagnostic during a conversion. If this was in the second
6572 standard conversion sequence of a user-defined conversion sequence, say
6573 which user-defined conversion. */
6575 static void
6577 {
6581 {
6585 }
6586 }
6588 /* Locate the parameter with the given index within FNDECL.
6589 ARGNUM is zero based, -1 indicates the `this' argument of a method.
6590 Return the location of the FNDECL itself if there are problems. */
6592 static location_t
6594 {
6596 tree param;
6598 /* Locate param by index within DECL_ARGUMENTS (fndecl). */
6602 ;
6604 /* If something went wrong (e.g. if we have a builtin and thus no arguments),
6605 return the location of FNDECL. */
6610 }
6612 /* Perform the conversions in CONVS on the expression EXPR. FN and
6613 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6614 indicates the `this' argument of a method. INNER is nonzero when
6615 being called to continue a conversion chain. It is negative when a
6616 reference binding will be applied, positive otherwise. If
6617 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6618 conversions will be emitted if appropriate. If C_CAST_P is true,
6619 this conversion is coming from a C-style cast; in that case,
6620 conversions to inaccessible bases are permitted. */
6622 static tree
6626 {
6628 diagnostic_t diag_kind;
6644 {
6648 /* Give a helpful error if this is bad because of excess braces. */
6653 {
6659 }
6661 /* Give a helpful error if this is bad because a conversion to bool
6662 from std::nullptr_t requires direct-initialization. */
6670 {
6672 {
6675 totype);
6681 complain);
6685 complain);
6686 else
6692 }
6694 {
6698 complain);
6700 }
6705 complain);
6708 }
6717 }
6723 {
6725 {
6729 /* We chose the surrogate function from add_conv_candidate, now we
6730 actually need to build the conversion. */
6736 /* When converting from an init list we consider explicit
6737 constructors, but actually trying to call one is an error. */
6740 /* Unless this is for direct-list-initialization. */
6742 /* And in C++98 a default constructor can't be explicit. */
6744 {
6750 {
6756 }
6757 else
6760 }
6762 /* If we're initializing from {}, it's value-initialization. */
6766 {
6771 {
6774 }
6776 }
6780 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6781 any more UDCs. */
6783 complain);
6785 /* If this is a constructor or a function returning an aggr type,
6786 we need to build up a TARGET_EXPR. */
6788 {
6791 /* Remember that this was list-initialization. */
6794 }
6797 }
6800 {
6806 else
6808 }
6815 /* We leave bad_p off ck_ambig because overload resolution considers
6816 it valid, it just fails when we try to perform it. So we need to
6817 check complain here, too. */
6819 {
6820 /* Call build_user_type_conversion again for the error. */
6822 complain);
6826 }
6830 {
6831 /* Conversion to std::initializer_list<T>. */
6839 /* Convert all the elements. */
6841 {
6852 }
6853 /* Build up the array. */
6854 elttype = cp_build_qualified_type
6858 /* Take the address explicitly rather than via decay_conversion
6859 to avoid the error about taking the address of a temporary. */
6865 /* Build up the initializer_list object. */
6873 }
6877 {
6886 }
6889 complain);
6896 };
6900 c_cast_p,
6901 complain);
6906 {
6910 {
6912 {
6917 }
6919 }
6924 /* Don't introduce copies when passing arguments along to the inherited
6925 constructor. */
6927 && flag_new_inheriting_ctors
6931 /* Fall through. */
6934 {
6935 /* We are going to bind a reference directly to a base-class
6936 subobject of EXPR. */
6937 /* Build an expression for `*((base*) &expr)'. */
6941 }
6943 /* Copy-initialization where the cv-unqualified version of the source
6944 type is the same class as, or a derived class of, the class of the
6945 destination [is treated as direct-initialization]. [dcl.init] */
6948 /* This conversion is being done in the context of a user-defined
6949 conversion (i.e. the second step of copy-initialization), so
6950 don't allow any more. */
6952 else
6955 /* standard_conversion got LOOKUP_PREFER_RVALUE. */
6959 /* Copy-list-initialization doesn't actually involve a copy. */
6963 {
6968 }
6973 {
6977 {
6990 else
6997 }
6999 /* If necessary, create a temporary.
7001 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
7002 that need temporaries, even when their types are reference
7003 compatible with the type of reference being bound, so the
7004 upcoming call to cp_build_addr_expr doesn't fail. */
7008 {
7009 /* Otherwise, a temporary of type "cv1 T1" is created and
7010 initialized from the initializer expression using the rules
7011 for a non-reference copy-initialization (8.5). */
7020 {
7021 /* If the reference is volatile or non-const, we
7022 cannot create a temporary. */
7029 else
7033 }
7034 /* If the source is a packed field, and we must use a copy
7035 constructor, then building the target expr will require
7036 binding the field to the reference parameter to the
7037 copy constructor, and we'll end up with an infinite
7038 loop. If we can use a bitwise copy, then we'll be
7039 OK. */
7043 {
7047 }
7049 {
7052 }
7054 }
7056 /* Take the address of the thing to which we will bind the
7057 reference. */
7062 /* Convert it to a pointer to the type referred to by the
7063 reference. This will adjust the pointer if a derived to
7064 base conversion is being performed. */
7067 /* Convert the pointer to the desired reference type. */
7069 }
7075 /* ??? Should the address of a transaction-safe pointer point to the TM
7076 clone, and this conversion look up the primary function? */
7080 /* Warn about deprecated conversion if appropriate. */
7096 }
7104 else
7108 }
7110 /* ARG is being passed to a varargs function. Perform any conversions
7111 required. Return the converted value. */
7113 tree
7115 {
7116 tree arg_type;
7119 /* [expr.call]
7121 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7122 standard conversions are performed. */
7125 /* [expr.call]
7127 If the argument has integral or enumeration type that is subject
7128 to the integral promotions (_conv.prom_), or a floating point
7129 type that is subject to the floating point promotion
7130 (_conv.fpprom_), the value of the argument is converted to the
7131 promoted type before the call. */
7136 {
7140 "implicit conversion from %qH to %qI when passing "
7144 }
7148 {
7150 {
7152 complain);
7162 }
7163 else
7165 }
7171 /* In a template (or ill-formed code), we can have an incomplete type
7172 even after require_complete_type_sfinae, in which case we don't know
7173 whether it has trivial copy or not. */
7176 {
7177 /* [expr.call] 5.2.2/7:
7178 Passing a potentially-evaluated argument of class type (Clause 9)
7179 with a non-trivial copy constructor or a non-trivial destructor
7180 with no corresponding parameter is conditionally-supported, with
7181 implementation-defined semantics.
7183 We support it as pass-by-invisible-reference, just like a normal
7184 value parameter.
7186 If the call appears in the context of a sizeof expression,
7187 it is not potentially-evaluated. */
7190 {
7194 "passing objects of non-trivially-copyable "
7196 arg_type);
7198 }
7199 /* Build up a real lvalue-to-rvalue conversion in case the
7200 copy constructor is trivial but not callable. */
7204 }
7207 }
7209 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7211 tree
7213 {
7215 {
7219 }
7229 {
7232 }
7236 {
7237 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7238 it as pass by invisible reference. */
7240 "receiving objects of non-trivially-copyable type %q#T "
7246 }
7250 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7251 know how to handle it. */
7254 }
7256 /* TYPE has been given to va_arg. Apply the default conversions which
7257 would have happened when passed via ellipsis. Return the promoted
7258 type, or the passed type if there is no change. */
7260 tree
7262 {
7263 tree promote;
7265 /* Perform the array-to-pointer and function-to-pointer
7266 conversions. */
7274 }
7276 /* ARG is a default argument expression being passed to a parameter of
7277 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7278 zero-based argument number. Do any required conversions. Return
7279 the converted value. */
7282 void
7286 void
7290 tree
7292 tsubst_flags_t complain)
7293 {
7295 tree t;
7297 /* See through clones. */
7299 /* And inheriting ctors. */
7303 /* Detect recursion. */
7306 {
7310 }
7312 /* If the ARG is an unparsed default argument expression, the
7313 conversion cannot be performed. */
7315 {
7320 }
7327 /* Due to:
7329 [dcl.fct.default]
7331 The names in the expression are bound, and the semantic
7332 constraints are checked, at the point where the default
7333 expressions appears.
7335 we must not perform access checks here. */
7337 /* We must make a copy of ARG, in case subsequent processing
7338 alters any part of it. */
7342 complain);
7349 }
7351 /* Returns the type which will really be used for passing an argument of
7352 type TYPE. */
7354 tree
7356 {
7357 /* Pass classes with copy ctors by invisible reference. */
7359 {
7361 /* There are no other pointers to this temporary. */
7363 }
7371 }
7373 /* Actually perform the appropriate conversion. */
7375 tree
7377 {
7378 tree bitfield_type;
7380 /* If VAL is a bitfield, then -- since it has already been converted
7381 to TYPE -- it cannot have a precision greater than TYPE.
7383 If it has a smaller precision, we must widen it here. For
7384 example, passing "int f:3;" to a function expecting an "int" will
7385 not result in any conversion before this point.
7387 If the precision is the same we must not risk widening. For
7388 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7389 often have type "int", even though the C++ type for the field is
7390 "long long". If the value is being passed to a function
7391 expecting an "int", then no conversions will be required. But,
7392 if we call convert_bitfield_to_declared_type, the bitfield will
7393 be converted to "long long". */
7400 ;
7401 /* Pass classes with copy ctors by invisible reference. */
7410 {
7412 {
7420 "argument of function call might be a candidate "
7422 }
7424 }
7426 }
7428 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7429 which just decay_conversion or no conversions at all should be done.
7430 This is true for some builtins which don't act like normal functions.
7431 Return 2 if no conversions at all should be done, 1 if just
7432 decay_conversion. Return 3 for special treatment of the 3rd argument
7433 for __builtin_*_overflow_p. */
7435 int
7437 {
7443 {
7458 }
7461 }
7463 /* Returns the decl of the dispatcher function if FN is a function version. */
7465 tree
7467 {
7477 {
7481 }
7486 }
7488 /* fn is a function version dispatcher that is marked used. Mark all the
7489 semantically identical function versions it will dispatch as used. */
7491 void
7493 {
7510 /* All semantically identical versions are chained. Traverse and mark each
7511 one of them as used. */
7514 {
7517 }
7518 }
7520 /* Build a call to "the copy constructor" for the type of A, even if it
7521 wouldn't be selected by normal overload resolution. Used for
7522 diagnostics. */
7524 static tree
7526 {
7537 }
7539 /* Return true iff T refers to a base field. */
7541 static bool
7543 {
7552 }
7554 /* We can't elide a copy from a function returning by value to a base
7555 subobject, as the callee might clobber tail padding. Return true iff this
7556 could be that case. */
7558 static bool
7560 {
7561 /* Copy elision only happens with a TARGET_EXPR. */
7565 /* It's safe to elide the copy for a class with no tail padding. */
7568 /* It's safe to elide the copy if we aren't initializing a base object. */
7572 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7577 }
7579 /* Subroutine of the various build_*_call functions. Overload resolution
7580 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7581 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7582 bitmask of various LOOKUP_* flags which apply to the call itself. */
7584 static tree
7586 {
7594 tree val;
7603 /* In a template, there is no need to perform all of the work that
7604 is normally done. We are only interested in the type of the call
7605 expression, i.e., the return type of the function. Any semantic
7606 errors will be deferred until the template is instantiated. */
7608 {
7610 tree return_type;
7621 else
7622 {
7625 tree arg;
7633 }
7643 }
7645 /* Give any warnings we noticed during overload resolution. */
7647 {
7651 }
7653 /* OK, we're actually calling this inherited constructor; set its deletedness
7654 appropriately. We can get away with doing this here because calling is
7655 the only way to refer to a constructor. */
7659 /* Make =delete work with SFINAE. */
7664 {
7665 tree access_fn;
7666 /* If FN is a template function, two cases must be considered.
7667 For example:
7669 struct A {
7670 protected:
7671 template <class T> void f();
7672 };
7673 template <class T> struct B {
7674 protected:
7675 void g();
7676 };
7677 struct C : A, B<int> {
7678 using A::f; // #1
7679 using B<int>::g; // #2
7680 };
7682 In case #1 where `A::f' is a member template, DECL_ACCESS is
7683 recorded in the primary template but not in its specialization.
7684 We check access of FN using its primary template.
7686 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7687 because it is a member of class template B, DECL_ACCESS is
7688 recorded in the specialization `B<int>::g'. We cannot use its
7689 primary template because `B<T>::g' and `B<int>::g' may have
7690 different access. */
7694 else
7699 }
7701 /* If we're checking for implicit delete, don't bother with argument
7702 conversions. */
7704 {
7706 {
7710 }
7714 /* Reject bad conversions now. */
7716 /* else continue to get conversion error. */
7717 }
7719 /* N3276 magic doesn't apply to nested calls. */
7723 /* Find maximum size of vector to hold converted arguments. */
7730 /* The implicit parameters to a constructor are not considered by overload
7731 resolution, and must be of the proper type. */
7733 {
7734 tree object_arg;
7736 {
7739 }
7740 else
7741 {
7744 }
7747 /* We should never try to call the abstract constructor. */
7751 {
7755 }
7758 {
7759 /* The implicit move specified in 15.8.3/3 fails "...if the type of
7760 the first parameter of the selected constructor is not an rvalue
7761 reference to the object’s type (possibly cv-qualified)...." */
7768 }
7769 }
7770 /* Bypass access control for 'this' parameter. */
7772 {
7775 ? first_arg
7778 tree converted_arg;
7779 tree base_binfo;
7785 {
7787 {
7792 }
7793 else
7795 }
7797 /* See if the function member or the whole class type is declared
7798 final and the call can be devirtualized. */
7803 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7804 X is called for an object that is not of type X, or of a type
7805 derived from X, the behavior is undefined.
7807 So we can assume that anything passed as 'this' is non-null, and
7808 optimize accordingly. */
7810 /* Convert to the base in which the function was declared. */
7813 arg,
7816 /* Check that the base class is accessible. */
7819 {
7824 else
7826 }
7827 /* If fn was found by a using declaration, the conversion path
7828 will be to the derived class, not the base declaring fn. We
7829 must convert from derived to base. */
7840 else
7844 }
7849 {
7856 /* If the argument is NULL and used to (implicitly) instantiate a
7857 template function (and bind one of the template arguments to
7858 the type of 'long int'), we don't want to warn about passing NULL
7859 to non-pointer argument.
7860 For example, if we have this template function:
7862 template<typename T> void func(T x) {}
7864 we want to warn (when -Wconversion is enabled) in this case:
7866 void foo() {
7867 func<int>(NULL);
7868 }
7870 but not in this case:
7872 void foo() {
7873 func(NULL);
7874 }
7875 */
7882 /* Warn about initializer_list deduction that isn't currently in the
7883 working draft. */
7885 && flag_deduce_init_list
7889 {
7902 {
7910 }
7911 }
7913 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7914 knows not to allow any more UDCs. This needs to happen after we
7915 process cand->warnings. */
7924 arg_complain);
7929 else
7931 }
7933 /* Default arguments */
7935 {
7941 complain);
7945 }
7947 /* Ellipsis */
7950 {
7953 {
7954 /* Do no conversions for certain magic varargs. */
7958 }
7960 /* For other magic varargs only do decay_conversion. */
7965 {
7966 /* Avoid infinite recursion trying to call A(...). */
7968 /* Try to call the actual copy constructor for a good error. */
7971 }
7972 else
7977 }
7982 /* Avoid to do argument-transformation, if warnings for format, and for
7983 nonnull are disabled. Just in case that at least one of them is active
7984 the check_function_arguments function might warn about something. */
7988 || warn_format
7989 || warn_suggest_attribute_format
7991 {
7999 }
8002 {
8003 /* Check for passing ellipsis arguments to an inherited constructor. We
8004 could handle this by open-coding the inherited constructor rather than
8005 defining it, but let's not bother now. */
8009 {
8011 {
8015 }
8017 }
8019 /* A base constructor inheriting from a virtual base doesn't get the
8020 inherited arguments, just this and __vtt. */
8023 }
8025 /* Avoid actually calling copy constructors and copy assignment operators,
8026 if possible. */
8033 /* It's unsafe to elide the constructor when handling
8034 a noexcept-expression, it may evaluate to the wrong
8035 value (c++/53025). */
8037 {
8038 tree targ;
8040 tree fa;
8043 /* Pull out the real argument, disregarding const-correctness. */
8045 /* Strip the reference binding for the constructor parameter. */
8049 /* But don't strip any other reference bindings; binding a temporary to a
8050 reference prevents copy elision. */
8056 {
8061 }
8062 else
8067 else
8070 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8071 subobject. */
8074 /* It's from binding the ref parm to a packed field. */
8077 /* See unsafe_copy_elision_p. */
8080 /* [class.copy]: the copy constructor is implicitly defined even if
8081 the implementation elided its use. */
8083 {
8087 }
8089 /* If we're creating a temp and we already have one, don't create a
8090 new one. If we're not creating a temp but we get one, use
8091 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8092 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8093 temp or an INIT_EXPR otherwise. */
8096 {
8101 }
8104 {
8106 RO_NULL,
8107 complain));
8111 }
8112 }
8116 {
8117 tree to = cp_stabilize_reference
8124 {
8125 /* Avoid copying empty classes. */
8128 }
8130 {
8133 /* Handle NSDMI that refer to the object being initialized. */
8135 }
8136 else
8137 {
8138 /* We must only copy the non-tail padding parts. */
8146 build_index_type
8155 }
8158 }
8161 {
8165 {
8168 else
8170 }
8171 }
8173 /* For calls to a multi-versioned function, overload resolution
8174 returns the function with the highest target priority, that is,
8175 the version that will checked for dispatching first. If this
8176 version is inlinable, a direct call to this version can be made
8177 otherwise the call should go through the dispatcher. */
8182 {
8188 }
8195 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8196 virtual functions can't be constexpr. */
8198 {
8199 tree t;
8206 complain);
8212 }
8213 else
8214 {
8218 }
8224 {
8226 /* build_new_op_1 will clear this when appropriate. */
8228 }
8230 {
8234 }
8236 }
8238 /* Return the DECL of the first non-public data member of class TYPE
8239 or null if none can be found. */
8241 static tree
8243 {
8248 {
8255 }
8261 {
8266 }
8269 }
8271 /* Return true if all copy and move assignment operator overloads for
8272 class TYPE are trivial and at least one of them is not deleted and,
8273 when ACCESS is set, accessible. Return false otherwise. Set
8274 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8275 copy or move assignment. */
8277 static bool
8279 {
8283 /* Iterate over overloads of the assignment operator, checking
8284 accessible copy assignments for triviality. */
8287 {
8290 /* Skip operators that aren't copy assignments. */
8297 /* Skip template assignment operators and deleted functions. */
8307 /* Break early when both properties have been determined. */
8310 }
8312 /* Return true if they're all trivial and one of the expressions
8313 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8318 }
8320 /* Return true if all copy and move ctor overloads for class TYPE are
8321 trivial and at least one of them is not deleted and, when ACCESS is
8322 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8323 to true when the TYPE has a (not necessarily trivial) default and copy
8324 (or move) ctor, respectively. */
8326 static bool
8328 {
8333 {
8336 /* Skip template constructors. */
8342 /* Skip ctors other than default, copy, and move. */
8358 /* Break early when both properties have been determined. */
8361 }
8364 }
8366 /* Issue a warning on a call to the built-in function FNDECL if it is
8367 a raw memory write whose destination is not an object of (something
8368 like) trivial or standard layout type with a non-deleted assignment
8369 and copy ctor. Detects const correctness violations, corrupting
8370 references, virtual table pointers, and bypassing non-trivial
8371 assignments. */
8373 static void
8375 {
8376 /* Except for bcopy where it's second, the destination pointer is
8377 the first argument for all functions handled here. Compute
8378 the index of the destination and source arguments. */
8386 /* Remove the outermost (usually implicit) conversion to the void*
8387 argument type. */
8393 /* Determine the type of the pointed-to object and whether it's
8394 a complete class type. */
8400 /* Check to see if the raw memory call is made by a ctor or dtor
8401 with this as the destination argument for the destination type.
8402 If so, be more permissive. */
8407 {
8413 /* A ctor and dtor for a class with no bases and no virtual functions
8414 can do whatever they want. Bail early with no further checking. */
8417 }
8419 /* True if the class is trivial. */
8422 /* Set to true if DESTYPE has an accessible copy assignment. */
8424 /* True if all of the class' overloaded copy assignment operators
8425 are all trivial (and not deleted) and at least one of them is
8426 accessible. */
8429 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8430 respectively. */
8433 /* True if all of the class' overloaded copy constructors are all
8434 trivial (and not deleted) and at least one of them is accessible. */
8437 /* Set FLD to the first private/protected member of the class. */
8440 /* The warning format string. */
8442 /* A suggested alternative to offer instead of the raw memory call.
8443 Empty string when none can be come up with. */
8448 {
8451 {
8452 /* Diagnose setting non-copy-assignable or non-trivial types,
8453 or types with a private member, to (potentially) non-zero
8454 bytes. Since the value of the bytes being written is unknown,
8455 suggest using assignment instead (if one exists). Also warn
8456 for writes into objects for which zero-initialization doesn't
8457 mean all bits clear (pointer-to-member data, where null is all
8458 bits set). Since the value being written is (most likely)
8459 non-zero, simply suggest assignment (but not copy assignment). */
8467 {
8470 "%qD writing to an object of type %#qT with "
8473 }
8479 }
8480 /* Fall through. */
8483 /* Similarly to the above, diagnose clearing non-trivial or non-
8484 standard layout objects, or objects of types with no assignmenmt.
8485 Since the value being written is known to be zero, suggest either
8486 copy assignment, copy ctor, or default ctor as an alternative,
8487 depending on what's available. */
8510 /* Determine the type of the source object. */
8514 /* Since it's impossible to determine wheter the byte copy is
8515 being used in place of assignment to an existing object or
8516 as a substitute for initialization, assume it's the former.
8517 Determine the best alternative to use instead depending on
8518 what's not deleted. */
8539 srctype))
8540 {
8541 /* Warn when copying into a non-trivial object from an object
8542 of a different type other than void or char. */
8544 "%qD copying an object of non-trivial type "
8547 }
8552 srctype))
8553 {
8556 "%qD copying an object of type %#qT with "
8557 "%qs member %qD from an array of %#qT; use "
8560 }
8562 {
8563 /* Finally, warn on partial copies. */
8564 unsigned HOST_WIDE_INT typesize
8571 "a non-trivial type %#qT leaves %wu "
8574 "a non-trivial type %#qT leaves %wu "
8577 }
8594 {
8595 /* Finally, warn on reallocation into insufficient space. */
8597 "%qD moving an object of non-trivial type "
8601 }
8606 }
8612 {
8616 else
8619 }
8623 }
8625 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8626 This function performs no overload resolution, conversion, or other
8627 high-level operations. */
8629 tree
8631 tsubst_flags_t complain)
8632 {
8633 tree fndecl;
8635 /* Remember roughly where this call is. */
8642 /* Check that arguments to builtin functions match the expectations. */
8646 {
8649 /* We need to take care that values to BUILT_IN_NORMAL
8650 are reduced. */
8658 /* Warn if the built-in writes to an object of a non-trivial type. */
8661 }
8663 /* If it is a built-in array notation function, then the return type of
8664 the function is the element type of the array passed in as array
8665 notation (i.e. the first parameter of the function). */
8667 {
8676 {
8678 {
8681 }
8682 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8683 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8684 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8685 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8686 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8687 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8688 The pre-defined return-type is the correct one. */
8692 }
8693 }
8698 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8699 function call is either the operand of a decltype-specifier or the
8700 right operand of a comma operator that is the operand of a
8701 decltype-specifier, a temporary object is not introduced for the
8702 prvalue. The type of the prvalue may be incomplete. */
8704 {
8710 {
8713 }
8714 }
8716 }
8718 /* Returns the value to use for the in-charge parameter when making a
8719 call to a function with the indicated NAME.
8721 FIXME:Can't we find a neater way to do this mapping? */
8723 tree
8725 {
8727 {
8731 }
8732 else
8733 {
8739 }
8742 }
8744 /* We've built up a constructor call RET. Complain if it delegates to the
8745 constructor we're currently compiling. */
8747 static void
8749 {
8755 }
8757 /* Build a call to a constructor, destructor, or an assignment
8758 operator for INSTANCE, an expression with class type. NAME
8759 indicates the special member function to call; *ARGS are the
8760 arguments. ARGS may be NULL. This may change ARGS. BINFO
8761 indicates the base of INSTANCE that is to be passed as the `this'
8762 parameter to the member function called.
8764 FLAGS are the LOOKUP_* flags to use when processing the call.
8766 If NAME indicates a complete object constructor, INSTANCE may be
8767 NULL_TREE. In this case, the caller will call build_cplus_new to
8768 store the newly constructed object into a VAR_DECL. */
8770 tree
8773 {
8774 tree fns;
8775 /* The type of the subobject to be constructed or destroyed. */
8776 tree class_type;
8778 tree ret;
8783 {
8784 /* Resolve the name. */
8789 }
8795 /* Handle the special case where INSTANCE is NULL_TREE. */
8798 else
8799 {
8803 /* Convert to the base class, if necessary. */
8806 {
8808 /* For constructors and destructors, either the base is
8809 non-virtual, or it is virtual but we are doing the
8810 conversion from a constructor or destructor for the
8811 complete object. In either case, we can convert
8812 statically. */
8814 else
8815 /* However, for assignment operators, we must convert
8816 dynamically if the base is virtual. */
8819 }
8820 }
8824 /* In C++17, "If the initializer expression is a prvalue and the
8825 cv-unqualified version of the source type is the same class as the class
8826 of the destination, the initializer expression is used to initialize the
8827 destination object." Handle that here to avoid doing overload
8828 resolution. */
8832 {
8835 /* FIXME P0135 doesn't say how to handle direct initialization from a
8836 type with a suitable conversion operator. Let's handle it like
8837 copy-initialization, but allowing explict conversions. */
8840 /* If we're using this to initialize a non-temporary object, don't
8841 require the destructor to be accessible. */
8845 sub_complain,
8846 flags);
8849 && (same_type_ignoring_top_level_qualifiers_p
8851 {
8857 /* Avoid change of behavior on Wunused-var-2.C. */
8860 }
8861 }
8865 /* When making a call to a constructor or destructor for a subobject
8866 that uses virtual base classes, pass down a pointer to a VTT for
8867 the subobject. */
8871 {
8872 tree vtt;
8873 tree sub_vtt;
8875 /* If the current function is a complete object constructor
8876 or destructor, then we fetch the VTT directly.
8877 Otherwise, we look it up using the VTT we were given. */
8885 else
8889 {
8892 }
8895 }
8900 complain);
8911 }
8913 /* Return the NAME, as a C string. The NAME indicates a function that
8914 is a member of TYPE. *FREE_P is set to true if the caller must
8915 free the memory returned.
8917 Rather than go through all of this, we should simply set the names
8918 of constructors and destructors appropriately, and dispense with
8919 ctor_identifier, dtor_identifier, etc. */
8923 {
8926 /* Assume that we will not allocate memory. */
8928 /* Constructors and destructors are special. */
8930 {
8931 pretty_name
8933 /* For a destructor, add the '~'. */
8935 {
8937 /* Remember that we need to free the memory allocated. */
8939 }
8940 }
8942 {
8945 TFF_PLAIN_IDENTIFIER),
8946 NULL);
8947 /* Remember that we need to free the memory allocated. */
8949 }
8950 else
8954 }
8956 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8957 be set, upon return, to the function called. ARGS may be NULL.
8958 This may change ARGS. */
8960 static tree
8964 {
8969 tree optype;
8971 tree name;
8974 tree call;
8975 tree fn;
8978 tree orig_instance;
8979 tree orig_fns;
8985 /* We don't know what function we're going to call, yet. */
8994 {
8998 }
9003 /* Dismantle the baselink to collect all the information we need. */
9011 {
9015 }
9026 {
9031 }
9034 /* Under DR 147 A::A() is an invalid constructor call,
9035 not a functional cast. */
9037 {
9049 complain);
9051 }
9053 /* Process the argument list. */
9055 {
9059 }
9061 /* Consider the object argument to be used even if we end up selecting a
9062 static member function. */
9066 /* Figure out whether to skip the first argument for the error
9067 message we will display to users if an error occurs. We don't
9068 want to display any compiler-generated arguments. The "this"
9069 pointer hasn't been added yet. However, we must remove the VTT
9070 pointer if this is a call to a base-class constructor or
9071 destructor. */
9074 {
9075 /* Callers should explicitly indicate whether they want to ctor
9076 the complete object or just the part without virtual bases. */
9079 /* Remove the VTT pointer, if present. */
9084 /* It's OK to call destructors and constructors on cv-qualified
9085 objects. Therefore, convert the INSTANCE to the unqualified
9086 type, if necessary. */
9088 {
9092 }
9093 }
9094 else
9097 /* For the overload resolution we need to find the actual `this`
9098 that would be captured if the call turns out to be to a
9099 non-static member function. Do not actually capture it at this
9100 point. */
9102 /* Constructors don't use the enclosing 'this'. */
9104 else
9107 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9110 /* The number of arguments artificial parms in ARGS; we subtract one because
9111 there's no 'this' in ARGS. */
9114 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9115 initializer, not T({ }). */
9119 {
9126 /* If the initializer list has no elements and T is a class type with
9127 a default constructor, the object is value-initialized. Handle
9128 this here so we don't need to handle it wherever we use
9129 build_special_member_call. */
9132 /* For a user-provided default constructor, use the normal
9133 mechanisms so that protected access works. */
9138 /* If BASETYPE is an aggregate, we need to do aggregate
9139 initialization. */
9141 {
9144 }
9147 {
9153 }
9155 /* Otherwise go ahead with overload resolution. */
9160 }
9161 else
9170 {
9172 {
9179 else
9180 {
9185 {
9188 }
9196 }
9198 }
9200 }
9201 else
9202 {
9205 {
9208 tree arglist;
9211 {
9219 else
9225 }
9227 }
9228 else
9229 {
9237 {
9238 /* This is not an error, it is runtime undefined
9239 behavior. */
9248 fn);
9249 }
9254 {
9259 {
9260 /* We captured 'this' in the current lambda now that
9261 we know we really need it. */
9263 }
9265 /* We can't tell until instantiation time whether we can use
9267 else
9268 {
9271 fn);
9273 }
9274 }
9277 {
9278 /* Optimize away vtable lookup if we know that this
9279 function can't be overridden. We need to check if
9280 the context and the type where we found fn are the same,
9281 actually FN might be defined in a different class
9282 type because of a using-declaration. In this case, we
9283 do not want to perform a non-virtual call. */
9285 && same_type_ignoring_top_level_qualifiers_p
9291 /* Now we know what function is being called. */
9294 /* Build the actual CALL_EXPR. */
9296 /* In an expression of the form `a->f()' where `f' turns
9297 out to be a static member function, `a' is
9298 none-the-less evaluated. */
9307 /* An explicit call of the form "x->~X()" has type
9308 "void". However, on platforms where destructors
9309 return "this" (i.e., those where
9310 targetm.cxx.cdtor_returns_this is true), such calls
9311 will appear to have a return value of pointer type
9312 to the low-level call machinery. We do not want to
9313 change the low-level machinery, since we want to be
9314 able to optimize "delete f()" on such platforms as
9315 "operator delete(~X(f()))" (rather than generating
9316 "t = f(), ~X(t), operator delete (t)"). */
9318 }
9319 }
9320 }
9323 {
9329 {
9332 }
9335 call = (build_min_non_dep_call_vec
9339 orig_args));
9344 }
9346 /* Free all the conversions we allocated. */
9353 }
9355 /* Wrapper for above. */
9357 tree
9361 {
9362 tree ret;
9368 }
9370 /* Returns true iff standard conversion sequence ICS1 is a proper
9371 subsequence of ICS2. */
9373 static bool
9375 {
9376 /* We can assume that a conversion of the same code
9377 between the same types indicates a subsequence since we only get
9378 here if the types we are converting from are the same. */
9385 {
9395 /* At this point, ICS1 cannot be a proper subsequence of
9396 ICS2. We can get a USER_CONV when we are comparing the
9397 second standard conversion sequence of two user conversion
9398 sequences. */
9413 }
9414 }
9416 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9417 be any _TYPE nodes. */
9419 bool
9421 {
9425 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9426 considers every class derived from itself. */
9429 }
9431 /* We build the ICS for an implicit object parameter as a pointer
9432 conversion sequence. However, such a sequence should be compared
9433 as if it were a reference conversion sequence. If ICS is the
9434 implicit conversion sequence for an implicit object parameter,
9435 modify it accordingly. */
9437 static void
9439 {
9441 {
9442 /* [over.match.funcs]
9444 For non-static member functions, the type of the
9445 implicit object parameter is "reference to cv X"
9446 where X is the class of which the function is a
9447 member and cv is the cv-qualification on the member
9448 function declaration. */
9450 tree reference_type;
9452 /* The `this' parameter is a pointer to a class type. Make the
9453 implicit conversion talk about a reference to that same class
9454 type. */
9467 }
9468 }
9470 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9471 and return the initial reference binding conversion. Otherwise,
9472 leave *ICS unchanged and return NULL. */
9476 {
9478 {
9483 }
9486 }
9488 /* Compare two implicit conversion sequences according to the rules set out in
9489 [over.ics.rank]. Return values:
9491 1: ics1 is better than ics2
9492 -1: ics2 is better than ics1
9493 0: ics1 and ics2 are indistinguishable */
9495 static int
9497 {
9498 tree from_type1;
9499 tree from_type2;
9500 tree to_type1;
9501 tree to_type2;
9508 /* REF_BINDING is nonzero if the result of the conversion sequence
9509 is a reference type. In that case REF_CONV is the reference
9510 binding conversion. */
9514 /* Compare badness before stripping the reference conversion. */
9520 /* Handle implicit object parameters. */
9524 /* Handle reference parameters. */
9528 /* List-initialization sequence L1 is a better conversion sequence than
9529 list-initialization sequence L2 if L1 converts to
9530 std::initializer_list<X> for some X and L2 does not. */
9536 /* [over.ics.rank]
9538 When comparing the basic forms of implicit conversion sequences (as
9539 defined in _over.best.ics_)
9541 --a standard conversion sequence (_over.ics.scs_) is a better
9542 conversion sequence than a user-defined conversion sequence
9543 or an ellipsis conversion sequence, and
9545 --a user-defined conversion sequence (_over.ics.user_) is a
9546 better conversion sequence than an ellipsis conversion sequence
9547 (_over.ics.ellipsis_). */
9548 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9549 mismatch. If both ICS are bad, we try to make a decision based on
9550 what would have happened if they'd been good. This is not an
9551 extension, we'll still give an error when we build up the call; this
9552 just helps us give a more helpful error message. */
9562 /* Both conversions are ellipsis conversions. */
9565 /* User-defined conversion sequence U1 is a better conversion sequence
9566 than another user-defined conversion sequence U2 if they contain the
9567 same user-defined conversion operator or constructor and if the sec-
9568 ond standard conversion sequence of U1 is better than the second
9569 standard conversion sequence of U2. */
9571 /* Handle list-conversion with the same code even though it isn't always
9572 ranked as a user-defined conversion and it doesn't have a second
9573 standard conversion sequence; it will still have the desired effect.
9574 Specifically, we need to do the reference binding comparison at the
9575 end of this function. */
9578 {
9594 {
9599 }
9600 else
9601 {
9602 /* For ambiguous or aggregate conversions, use the target type as
9603 a proxy for the conversion function. */
9606 }
9608 /* We can just fall through here, after setting up
9609 FROM_TYPE1 and FROM_TYPE2. */
9612 }
9613 else
9614 {
9618 /* We're dealing with two standard conversion sequences.
9620 [over.ics.rank]
9622 Standard conversion sequence S1 is a better conversion
9623 sequence than standard conversion sequence S2 if
9625 --S1 is a proper subsequence of S2 (comparing the conversion
9626 sequences in the canonical form defined by _over.ics.scs_,
9627 excluding any Lvalue Transformation; the identity
9628 conversion sequence is considered to be a subsequence of
9629 any non-identity conversion sequence */
9640 }
9642 /* One sequence can only be a subsequence of the other if they start with
9643 the same type. They can start with different types when comparing the
9644 second standard conversion sequence in two user-defined conversion
9645 sequences. */
9647 {
9652 }
9654 /* [over.ics.rank]
9656 Or, if not that,
9658 --the rank of S1 is better than the rank of S2 (by the rules
9659 defined below):
9661 Standard conversion sequences are ordered by their ranks: an Exact
9662 Match is a better conversion than a Promotion, which is a better
9663 conversion than a Conversion.
9665 Two conversion sequences with the same rank are indistinguishable
9666 unless one of the following rules applies:
9668 --A conversion that does not a convert a pointer, pointer to member,
9669 or std::nullptr_t to bool is better than one that does.
9671 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9672 so that we do not have to check it explicitly. */
9681 /* A conversion from scalar arithmetic type to complex is worse than a
9682 conversion between scalar arithmetic types. */
9689 {
9692 else
9694 }
9700 {
9705 }
9706 /* The rules for pointers to members A::* are just like the rules
9707 for pointers A*, except opposite: if B is derived from A then
9708 A::* converts to B::*, not vice versa. For that reason, we
9709 switch the from_ and to_ variables here. */
9716 {
9721 }
9726 {
9727 /* This was one of the pointer or pointer-like conversions.
9729 [over.ics.rank]
9731 --If class B is derived directly or indirectly from class A,
9732 conversion of B* to A* is better than conversion of B* to
9733 void*, and conversion of A* to void* is better than
9734 conversion of B* to void*. */
9737 {
9739 deref_from_type2))
9742 deref_from_type1))
9744 }
9747 {
9749 {
9751 {
9753 deref_to_type1))
9755 }
9756 /* We know that DEREF_TO_TYPE1 is `void' here. */
9758 deref_to_type2))
9760 }
9761 }
9764 {
9765 /* [over.ics.rank]
9767 --If class B is derived directly or indirectly from class A
9768 and class C is derived directly or indirectly from B,
9770 --conversion of C* to B* is better than conversion of C* to
9771 A*,
9773 --conversion of B* to A* is better than conversion of C* to
9774 A* */
9776 {
9778 deref_to_type2))
9781 deref_to_type1))
9783 }
9785 {
9787 deref_from_type1))
9790 deref_from_type2))
9792 }
9793 }
9794 }
9797 {
9800 /* [over.ics.rank]
9802 --binding of an expression of type C to a reference of type
9803 B& is better than binding an expression of type C to a
9804 reference of type A&
9806 --conversion of C to B is better than conversion of C to A, */
9809 {
9814 }
9815 }
9818 {
9821 /* [over.ics.rank]
9823 --binding of an expression of type B to a reference of type
9824 A& is better than binding an expression of type C to a
9825 reference of type A&,
9827 --conversion of B to A is better than conversion of C to A */
9830 {
9835 }
9836 }
9838 /* [over.ics.rank]
9840 --S1 and S2 differ only in their qualification conversion and yield
9841 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9842 qualification signature of type T1 is a proper subset of the cv-
9843 qualification signature of type T2 */
9847 {
9851 }
9853 /* [over.ics.rank]
9855 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9856 to an implicit object parameter of a non-static member function
9857 declared without a ref-qualifier, and either S1 binds an lvalue
9858 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9859 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9860 draft standard, 13.3.3.2)
9862 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9863 types to which the references refer are the same type except for
9864 top-level cv-qualifiers, and the type to which the reference
9865 initialized by S2 refers is more cv-qualified than the type to
9866 which the reference initialized by S1 refers.
9868 DR 1328 [over.match.best]: the context is an initialization by
9869 conversion function for direct reference binding (13.3.1.6) of a
9870 reference to function type, the return type of F1 is the same kind of
9871 reference (i.e. lvalue or rvalue) as the reference being initialized,
9872 and the return type of F2 is not. */
9875 {
9882 {
9886 /* Don't prefer a bad conversion that drops cv-quals to a bad
9887 conversion with the wrong rvalueness. */
9891 }
9894 {
9898 {
9899 /* Prefer the one that drops fewer cv-quals. */
9904 }
9906 }
9907 }
9909 /* Neither conversion sequence is better than the other. */
9911 }
9913 /* The source type for this standard conversion sequence. */
9915 static tree
9917 {
9919 {
9924 }
9926 }
9928 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9929 a pointer to LOSER and re-running joust to produce the warning if WINNER
9930 is actually used. */
9932 static void
9934 {
9940 }
9942 /* Compare two candidates for overloading as described in
9943 [over.match.best]. Return values:
9945 1: cand1 is better than cand2
9946 -1: cand2 is better than cand1
9947 0: cand1 and cand2 are indistinguishable */
9949 static int
9951 tsubst_flags_t complain)
9952 {
9958 /* Candidates that involve bad conversions are always worse than those
9959 that don't. */
9965 /* If we have two pseudo-candidates for conversions to the same type,
9966 or two candidates for the same function, arbitrarily pick one. */
9971 /* Prefer a non-deleted function over an implicitly deleted move
9972 constructor or assignment operator. This differs slightly from the
9973 wording for issue 1402 (which says the move op is ignored by overload
9974 resolution), but this way produces better error messages. */
9978 {
9985 }
9987 /* a viable function F1
9988 is defined to be a better function than another viable function F2 if
9989 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9990 ICSi(F2), and then */
9992 /* for some argument j, ICSj(F1) is a better conversion sequence than
9993 ICSj(F2) */
9995 /* For comparing static and non-static member functions, we ignore
9996 the implicit object parameter of the non-static function. The
9997 standard says to pretend that the static function has an object
9998 parm, but that won't work with operator overloading. */
10001 {
10007 /* We're comparing a near-match list constructor and a near-match
10008 non-list constructor. Just treat them as unordered. */
10015 else
10016 {
10019 }
10020 }
10023 {
10029 {
10031 && warn_sign_promo
10043 {
10050 else
10055 {
10059 }
10060 else
10062 }
10065 {
10068 }
10070 }
10071 }
10073 /* warn about confusing overload resolution for user-defined conversions,
10074 either between a constructor and a conversion op, or between two
10075 conversion ops. */
10080 {
10086 else
10089 /* We don't want to complain about `X::operator T1 ()'
10090 beating `X::operator T2 () const', when T2 is a no less
10091 cv-qualified version of T1. */
10094 {
10099 {
10102 }
10105 }
10106 else
10112 {
10119 {
10121 }
10122 }
10123 else
10125 }
10130 /* DR 495 moved this tiebreaker above the template ones. */
10131 /* or, if not that,
10132 the context is an initialization by user-defined conversion (see
10133 _dcl.init_ and _over.match.user_) and the standard conversion
10134 sequence from the return type of F1 to the destination type (i.e.,
10135 the type of the entity being initialized) is a better conversion
10136 sequence than the standard conversion sequence from the return type
10137 of F2 to the destination type. */
10140 {
10144 }
10146 /* or, if not that,
10147 F1 is a non-template function and F2 is a template function
10148 specialization. */
10155 /* or, if not that,
10156 F1 and F2 are template functions and the function template for F1 is
10157 more specialized than the template for F2 according to the partial
10158 ordering rules. */
10161 {
10162 winner = more_specialized_fn
10165 /* [temp.func.order]: The presence of unused ellipsis and default
10166 arguments has no effect on the partial ordering of function
10167 templates. add_function_candidate() will not have
10168 counted the "this" argument for constructors. */
10172 }
10174 // C++ Concepts
10175 // or, if not that, F1 is more constrained than F2.
10177 {
10181 }
10183 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10185 {
10187 /* We distinguish between candidates from an explicit deduction guide and
10188 candidates built from a constructor based on DECL_ARTIFICIAL. */
10195 {
10196 /* Prefer the special copy guide over a declared copy/move
10197 constructor. */
10203 /* Prefer a candidate generated from a non-template constructor. */
10208 }
10209 }
10211 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10212 for all arguments the corresponding parameters of F1 and F2 have the same
10213 type (CWG 2273/2277). */
10218 {
10232 {
10234 {
10239 }
10242 }
10243 }
10245 /* Check whether we can discard a builtin candidate, either because we
10246 have two identical ones or matching builtin and non-builtin candidates.
10248 (Pedantically in the latter case the builtin which matched the user
10249 function should not be added to the overload set, but we spot it here.
10251 [over.match.oper]
10252 ... the builtin candidates include ...
10253 - do not have the same parameter type list as any non-template
10254 non-member candidate. */
10257 {
10263 {
10265 /* Two built-in candidates; arbitrarily pick one. */
10268 /* cand1 is built-in; prefer cand2. */
10270 else
10271 /* cand2 is built-in; prefer cand1. */
10273 }
10274 }
10276 /* For candidates of a multi-versioned function, make the version with
10277 the highest priority win. This version will be checked for dispatching
10278 first. If this version can be inlined into the caller, the front-end
10279 will simply make a direct call to this function. */
10285 {
10291 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10292 is possible that cand1->fn and cand2->fn are function versions but of
10293 different functions. Check types to see if they are versions of the same
10294 function. */
10297 {
10298 /* Always make the version with the higher priority, more
10299 specialized, win. */
10303 else
10305 }
10306 }
10308 /* If the two function declarations represent the same function (this can
10309 happen with declarations in multiple scopes and arg-dependent lookup),
10310 arbitrarily choose one. But first make sure the default args we're
10311 using match. */
10314 {
10321 {
10322 /* Don't crash if the fn is variadic. */
10327 }
10335 {
10338 {
10340 {
10342 {
10344 "default argument mismatch in "
10346 {
10351 }
10352 }
10353 else
10355 }
10356 else
10359 }
10362 }
10365 }
10367 tweak:
10369 /* Extension: If the worst conversion for one candidate is worse than the
10370 worst conversion for the other, take the first. */
10372 {
10377 {
10382 }
10388 {
10389 /* Don't choose a deleted function over ambiguity. */
10393 {
10395 "ISO C++ says that these are ambiguous, even "
10396 "though the worst conversion for the first is better than "
10400 }
10401 else
10404 }
10405 }
10409 }
10411 /* Given a list of candidates for overloading, find the best one, if any.
10412 This algorithm has a worst case of O(2n) (winner is last), and a best
10413 case of O(n/2) (totally ambiguous); much better than a sorting
10414 algorithm. */
10418 {
10423 /* Walk through the list once, comparing each current champ to the next
10424 candidate, knocking out a candidate or two with each comparison. */
10427 {
10431 else
10432 {
10434 {
10439 }
10440 else
10441 {
10444 }
10447 }
10448 }
10450 /* Make sure the champ is better than all the candidates it hasn't yet
10451 been compared to. */
10454 challenger != champ
10457 {
10461 }
10464 }
10466 /* Returns nonzero if things of type FROM can be converted to TO. */
10468 bool
10470 {
10472 /* implicit_conversion only considers user-defined conversions
10473 if it has an expression for the call argument list. */
10477 }
10479 /* Returns nonzero if things of type FROM can be converted to TO with a
10480 standard conversion. */
10482 bool
10484 {
10486 }
10488 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10490 bool
10492 tsubst_flags_t complain)
10493 {
10498 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10500 /* We want to discard any access checks done for this test,
10501 as we might not be in the appropriate access context and
10502 we'll do the check again when we actually perform the
10503 conversion. */
10510 /* Discard the access checks now. */
10512 /* Free all the conversions we allocated. */
10516 }
10518 /* Like can_convert_arg, but allows dubious conversions as well. */
10520 bool
10522 tsubst_flags_t complain)
10523 {
10527 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10529 /* Try to perform the conversion. */
10532 /* Free all the conversions we allocated. */
10536 }
10538 /* Convert EXPR to TYPE. Return the converted expression.
10540 Note that we allow bad conversions here because by the time we get to
10541 this point we are committed to doing the conversion. If we end up
10542 doing a bad conversion, convert_like will complain. */
10544 tree
10547 {
10555 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10563 {
10565 {
10566 /* If expr has unknown type, then it is an overloaded function.
10567 Call instantiate_type to get good error messages. */
10572 else
10575 }
10577 }
10579 {
10580 /* In a template, we are only concerned about determining the
10581 type of non-dependent expressions, so we do not have to
10582 perform the actual conversion. But for initializers, we
10583 need to be able to perform it at instantiation
10584 (or instantiate_non_dependent_expr) time. */
10588 }
10589 else
10592 /* Free all the conversions we allocated. */
10596 }
10598 tree
10600 {
10602 LOOKUP_IMPLICIT);
10603 }
10605 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10606 permitted. If the conversion is valid, the converted expression is
10607 returned. Otherwise, NULL_TREE is returned, except in the case
10608 that TYPE is a class type; in that case, an error is issued. If
10609 C_CAST_P is true, then this direct-initialization is taking
10610 place as part of a static_cast being attempted as part of a C-style
10611 cast. */
10613 tree
10615 tree expr,
10617 tsubst_flags_t complain)
10618 {
10624 /* [dcl.init]
10626 If the destination type is a (possibly cv-qualified) class type:
10628 -- If the initialization is direct-initialization ...,
10629 constructors are considered. ... If no constructor applies, or
10630 the overload resolution is ambiguous, the initialization is
10631 ill-formed. */
10633 {
10639 }
10641 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10645 c_cast_p,
10649 else
10652 c_cast_p,
10653 complain);
10655 /* Free all the conversions we allocated. */
10659 }
10661 /* When initializing a reference that lasts longer than a full-expression,
10662 this special rule applies:
10664 [class.temporary]
10666 The temporary to which the reference is bound or the temporary
10667 that is the complete object to which the reference is bound
10668 persists for the lifetime of the reference.
10670 The temporaries created during the evaluation of the expression
10671 initializing the reference, except the temporary to which the
10672 reference is bound, are destroyed at the end of the
10673 full-expression in which they are created.
10675 In that case, we store the converted expression into a new
10676 VAR_DECL in a new scope.
10678 However, we want to be careful not to create temporaries when
10679 they are not required. For example, given:
10681 struct B {};
10682 struct D : public B {};
10683 D f();
10684 const B& b = f();
10686 there is no need to copy the return value from "f"; we can just
10687 extend its lifetime. Similarly, given:
10689 struct S {};
10690 struct T { operator S(); };
10691 T t;
10692 const S& s = t;
10694 we can extend the lifetime of the return value of the conversion
10695 operator.
10697 The next several functions are involved in this lifetime extension. */
10699 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10700 reference is being bound to a temporary. Create and return a new
10701 VAR_DECL with the indicated TYPE; this variable will store the value to
10702 which the reference is bound. */
10704 tree
10706 {
10709 /* Register the variable. */
10712 {
10713 /* Namespace-scope or local static; give it a mangled name. */
10714 /* FIXME share comdat with decl? */
10725 }
10726 else
10727 /* Create a new cleanup level if necessary. */
10731 }
10733 /* EXPR is the initializer for a variable DECL of reference or
10734 std::initializer_list type. Create, push and return a new VAR_DECL
10735 for the initializer so that it will live as long as DECL. Any
10736 cleanup for the new variable is returned through CLEANUP, and the
10737 code to initialize the new variable is returned through INITP. */
10739 static tree
10742 {
10743 tree init;
10744 tree type;
10745 tree var;
10747 /* Create the temporary variable. */
10751 /* If the rvalue is the result of a function call it will be
10752 a TARGET_EXPR. If it is some other construct (such as a
10753 member access expression where the underlying object is
10754 itself the result of a function call), turn it into a
10755 TARGET_EXPR here. It is important that EXPR be a
10756 TARGET_EXPR below since otherwise the INIT_EXPR will
10757 attempt to make a bitwise copy of EXPR to initialize
10758 VAR. */
10764 {
10768 }
10770 /* Recursively extend temps in this initializer. */
10774 /* Any reference temp has a non-trivial initializer. */
10777 /* If the initializer is constant, put it in DECL_INITIAL so we get
10778 static initialization and use in constant expressions. */
10781 {
10783 {
10784 /* 5.19 says that a constant expression can include an
10785 lvalue-rvalue conversion applied to "a glvalue of literal type
10786 that refers to a non-volatile temporary object initialized
10787 with a constant expression". Rather than try to communicate
10788 that this VAR_DECL is a temporary, just mark it constexpr.
10790 Currently this is only useful for initializer_list temporaries,
10791 since reference vars can't appear in constant expressions. */
10795 }
10798 }
10799 else
10800 /* Create the INIT_EXPR that will initialize the temporary
10801 variable. */
10804 {
10809 else
10810 {
10814 }
10816 /* We must be careful to destroy the temporary only
10817 after its initialization has taken place. If the
10818 initialization throws an exception, then the
10819 destructor should not be run. We cannot simply
10820 transform INIT into something like:
10822 (INIT, ({ CLEANUP_STMT; }))
10824 because emit_local_var always treats the
10825 initializer as a full-expression. Thus, the
10826 destructor would run too early; it would run at the
10827 end of initializing the reference variable, rather
10828 than at the end of the block enclosing the
10829 reference variable.
10831 The solution is to pass back a cleanup expression
10832 which the caller is responsible for attaching to
10833 the statement tree. */
10834 }
10835 else
10836 {
10839 {
10842 tls_aggregates);
10843 else
10845 static_aggregates);
10846 }
10847 else
10848 /* Check whether the dtor is callable. */
10850 }
10851 /* Avoid -Wunused-variable warning (c++/38958). */
10858 }
10860 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10861 initializing a variable of that TYPE. */
10863 tree
10866 {
10874 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10880 {
10882 {
10891 else
10895 }
10897 }
10900 /* Perform the conversion. */
10903 /* We gave an error in build_user_type_conversion_1. */
10905 else
10908 /* Free all the conversions we allocated. */
10912 }
10914 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10915 which is bound either to a reference or a std::initializer_list. */
10917 static tree
10919 {
10924 {
10928 }
10931 /* Deal with binding to a subobject. */
10935 {
10943 }
10945 }
10947 /* INIT is part of the initializer for DECL. If there are any
10948 reference or initializer lists being initialized, extend their
10949 lifetime to match that of DECL. */
10951 tree
10953 {
10959 else
10960 {
10965 {
10967 {
10968 /* The temporary array underlying a std::initializer_list
10969 is handled like a reference temporary. */
10973 }
10974 else
10975 {
10981 }
10985 }
10986 }
10989 }
10991 /* Returns true iff an initializer for TYPE could contain temporaries that
10992 need to be extended because they are bound to references or
10993 std::initializer_list. */
10995 bool
10997 {
11002 {
11009 }
11011 }
11013 /* Returns true iff TYPE is some variant of std::initializer_list. */
11015 bool
11017 {
11022 /* Look through typedefs. */
11027 }
11029 /* Returns true iff DECL is a list constructor: i.e. a constructor which
11030 will accept an argument list of a single std::initializer_list<T>. */
11032 bool
11034 {
11036 tree arg;
11048 /* There are more non-defaulted parms. */
11052 }