| blob | cfedd30cea35a18f58297ae6db23c1c81a1ee04d |
1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2017 Free Software Foundation, Inc.
3 Contributed by Michael Tiemann (tiemann@cygnus.com) and
4 modified by Brendan Kehoe (brendan@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
23 /* High-level class interface. */
45 /* The various kinds of conversion. */
48 ck_identity,
49 ck_lvalue,
50 ck_fnptr,
51 ck_qual,
52 ck_std,
53 ck_ptr,
54 ck_pmem,
55 ck_base,
56 ck_ref_bind,
57 ck_user,
58 ck_ambig,
59 ck_list,
60 ck_aggr,
61 ck_rvalue
62 };
64 /* The rank of the conversion. Order of the enumerals matters; better
65 conversions should come earlier in the list. */
68 cr_identity,
69 cr_exact,
70 cr_promotion,
71 cr_std,
72 cr_pbool,
73 cr_user,
74 cr_ellipsis,
75 cr_bad
76 };
78 /* An implicit conversion sequence, in the sense of [over.best.ics].
79 The first conversion to be performed is at the end of the chain.
80 That conversion is always a cr_identity conversion. */
83 /* The kind of conversion represented by this step. */
84 conversion_kind kind;
85 /* The rank of this conversion. */
86 conversion_rank rank;
90 /* True if this conversion would be permitted with a bending of
91 language standards, e.g. disregarding pointer qualifiers or
92 converting integers to pointers. */
94 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
95 temporary should be created to hold the result of the
96 conversion. */
98 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
99 from a pointer-to-derived to pointer-to-base is being performed. */
101 /* If KIND is ck_ref_bind, true when either an lvalue reference is
102 being bound to an lvalue expression or an rvalue reference is
103 being bound to an rvalue expression. If KIND is ck_rvalue,
104 true when we are treating an lvalue as an rvalue (12.8p33). If
105 KIND is ck_base, always false. */
108 /* The type of the expression resulting from the conversion. */
109 tree type;
111 /* The next conversion in the chain. Since the conversions are
112 arranged from outermost to innermost, the NEXT conversion will
113 actually be performed before this conversion. This variant is
114 used only when KIND is neither ck_identity, ck_ambig nor
115 ck_list. Please use the next_conversion function instead
116 of using this field directly. */
118 /* The expression at the beginning of the conversion chain. This
119 variant is used only if KIND is ck_identity or ck_ambig. */
120 tree expr;
121 /* The array of conversions for an initializer_list, so this
122 variant is used only when KIN D is ck_list. */
125 /* The function candidate corresponding to this conversion
126 sequence. This field is only used if KIND is ck_user. */
128 };
130 #define CONVERSION_RANK(NODE) \
131 ((NODE)->bad_p ? cr_bad \
132 : (NODE)->ellipsis_p ? cr_ellipsis \
133 : (NODE)->user_conv_p ? cr_user \
134 : (NODE)->rank)
136 #define BAD_CONVERSION_RANK(NODE) \
137 ((NODE)->ellipsis_p ? cr_ellipsis \
138 : (NODE)->user_conv_p ? cr_user \
139 : (NODE)->rank)
148 tsubst_flags_t);
151 #define convert_like(CONV, EXPR, COMPLAIN) \
152 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, \
155 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
156 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), \
164 tsubst_flags_t);
176 static void add_builtin_candidates
179 static void add_builtin_candidate
183 static void build_builtin_candidate
193 tsubst_flags_t);
195 tsubst_flags_t);
215 tsubst_flags_t);
219 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
220 NAME can take many forms... */
222 bool
224 {
225 /* Just accept something we've already complained about. */
234 {
239 else
241 }
242 else
243 {
244 /* In the case of:
246 template <class T> struct S { ~S(); };
247 int i;
248 i.~S();
250 NAME will be a class template. */
253 }
258 }
260 /* We want the address of a function or method. We avoid creating a
261 pointer-to-member function. */
263 tree
265 {
268 /* We have to do these by hand to avoid real pointer to member
269 functions. */
271 {
273 {
277 complain);
278 }
280 }
281 else
285 }
287 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
288 POINTER_TYPE to those. Note, pointer to member function types
289 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
290 two variants. build_call_a is the primitive taking an array of
291 arguments, while build_call_n is a wrapper that handles varargs. */
293 tree
295 {
298 else
299 {
309 }
310 }
312 /* Update various flags in cfun and the call itself based on what is being
313 called. Split out of build_call_a so that bot_manip can use it too. */
315 void
317 {
321 /* We check both the decl and the type; a function may be known not to
322 throw without being declared throw(). */
336 }
338 tree
340 {
341 tree decl;
342 tree result_type;
343 tree fntype;
353 /* An rvalue has no cv-qualifiers. */
364 {
365 /* We invoke build_call directly for several library
366 functions. These may have been declared normally if
367 we're building libgcc, so we can't just check
368 DECL_ARTIFICIAL. */
373 }
380 && flag_new_inheriting_ctors
384 /* Pass arguments directly to the inherited constructor. */
387 /* Don't pass empty class objects by value. This is useful
388 for tags in STL, which are used to control overload resolution.
389 We don't need to handle other cases of copying empty classes. */
392 {
396 {
400 }
401 }
404 }
406 /* New overloading code. */
413 };
415 /* Information for providing diagnostics about why overloading failed. */
418 rr_none,
419 rr_arity,
420 rr_explicit_conversion,
421 rr_template_conversion,
422 rr_arg_conversion,
423 rr_bad_arg_conversion,
424 rr_template_unification,
425 rr_invalid_copy,
426 rr_inherited_ctor,
427 rr_constraint_failure
428 };
431 /* The index of the argument, 0-based. */
433 /* The actual argument or its type. */
434 tree from;
435 /* The type of the parameter. */
436 tree to_type;
437 };
442 /* Information about an arity mismatch. */
444 /* The expected number of arguments. */
446 /* The actual number of arguments in the call. */
448 /* Whether the call was a varargs call. */
451 /* Information about an argument conversion mismatch. */
453 /* Same, but for bad argument conversions. */
455 /* Information about template unification failures. These are the
456 parameters passed to fn_type_unification. */
458 tree tmpl;
459 tree explicit_targs;
463 tree return_type;
464 unification_kind_t strict;
467 /* Information about template instantiation failures. These are the
468 parameters passed to instantiate_template. */
470 tree tmpl;
471 tree targs;
474 };
477 /* The FUNCTION_DECL that will be called if this candidate is
478 selected by overload resolution. */
479 tree fn;
480 /* If not NULL_TREE, the first argument to use when calling this
481 function. */
482 tree first_arg;
483 /* The rest of the arguments to use when calling this function. If
484 there are no further arguments this may be NULL or it may be an
485 empty vector. */
487 /* The implicit conversion sequences for each of the arguments to
488 FN. */
490 /* The number of implicit conversion sequences. */
492 /* If FN is a user-defined conversion, the standard conversion
493 sequence from the type returned by FN to the desired destination
494 type. */
497 /* If FN is a member function, the binfo indicating the path used to
498 qualify the name of FN at the call site. This path is used to
499 determine whether or not FN is accessible if it is selected by
500 overload resolution. The DECL_CONTEXT of FN will always be a
501 (possibly improper) base of this binfo. */
502 tree access_path;
503 /* If FN is a non-static member function, the binfo indicating the
504 subobject to which the `this' pointer should be converted if FN
505 is selected by overload resolution. The type pointed to by
506 the `this' pointer must correspond to the most derived class
507 indicated by the CONVERSION_PATH. */
508 tree conversion_path;
509 tree template_decl;
510 tree explicit_targs;
515 /* The flags active in add_candidate. */
517 };
519 /* Returns true iff T is a null pointer constant in the sense of
520 [conv.ptr]. */
522 bool
524 {
527 /* [conv.ptr]
529 A null pointer constant is an integral constant expression
530 (_expr.const_) rvalue of integer type that evaluates to zero or
531 an rvalue of type std::nullptr_t. */
536 {
537 /* Core issue 903 says only literal 0 is a null pointer constant. */
544 }
546 {
551 }
554 }
556 /* Returns true iff T is a null member pointer value (4.11). */
558 bool
560 {
569 else
571 }
573 /* Returns nonzero if PARMLIST consists of only default parms,
574 ellipsis, and/or undeduced parameter packs. */
576 bool
578 {
585 }
587 /* Allocate N bytes of memory from the conversion obstack. The memory
588 is zeroed before being returned. */
592 {
595 {
598 }
602 }
604 /* Allocate rejection reasons. */
608 {
613 }
617 {
623 }
627 {
634 }
638 {
645 }
649 {
655 }
659 {
665 }
672 {
679 /* Copy args to our own storage. */
687 }
691 {
693 }
697 {
700 }
704 {
707 }
709 // Build a constraint failure record, saving information into the
710 // template_instantiation field of the rejection. If FN is not a template
711 // declaration, the TMPL member is the FN declaration and TARGS is empty.
715 {
718 {
721 }
722 else
723 {
726 }
728 }
730 /* Dynamically allocate a conversion. */
734 {
739 }
741 /* Make sure that all memory on the conversion obstack has been
742 freed. */
744 void
746 {
750 }
752 /* Dynamically allocate an array of N conversions. */
756 {
758 }
762 {
766 /* Note that the caller is responsible for filling in t->cand for
767 user-defined conversions. */
773 {
790 }
796 }
798 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
799 specialization of std::initializer_list<T>, if such a conversion is
800 possible. */
804 {
810 tree val;
812 /* Within a list-initialization we can have more user-defined
813 conversions. */
815 /* But no narrowing conversions. */
818 /* Can't make an array of these types. */
825 {
826 conversion *sub
833 }
841 {
849 }
852 }
854 /* Return the next conversion of the conversion chain (if applicable),
855 or NULL otherwise. Please use this function instead of directly
856 accessing fields of struct conversion. */
860 {
867 }
869 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
870 is a valid aggregate initializer for array type ATYPE. */
872 static bool
874 {
878 {
884 else
886 complain);
889 }
891 }
893 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
894 aggregate class, if such a conversion is possible. */
898 {
904 /* We already called reshape_init in implicit_conversion. */
906 /* The conversions within the init-list aren't affected by the enclosing
907 context; they're always simple copy-initialization. */
911 {
913 tree val;
921 /* Value-initialization of reference is ill-formed. */
923 else
924 {
928 }
934 else
936 complain);
943 }
955 }
957 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
958 array type, if such a conversion is possible. */
962 {
967 tree val;
972 /* We might need to propagate the size from the element to the array. */
977 {
981 }
986 {
987 conversion *sub
999 }
1008 }
1010 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1011 complex type, if such a conversion is possible. */
1015 tsubst_flags_t complain)
1016 {
1021 tree val;
1032 {
1033 conversion *sub
1045 }
1054 }
1056 /* Build a representation of the identity conversion from EXPR to
1057 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1061 {
1069 }
1071 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1072 were multiple user-defined conversions to accomplish the job.
1073 Build a conversion that indicates that ambiguity. */
1077 {
1085 }
1087 tree
1089 {
1093 }
1095 /* Returns the standard conversion path (see [conv]) from type FROM to type
1096 TO, if any. For proper handling of null pointer constants, you must
1097 also pass the expression EXPR to convert from. If C_CAST_P is true,
1098 this conversion is coming from a C-style cast. */
1103 {
1107 tree qualified_to;
1111 {
1114 }
1120 {
1122 {
1128 }
1130 {
1131 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1134 }
1135 }
1142 {
1146 }
1147 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1148 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1149 express the copy constructor call required by copy-initialization. */
1151 {
1153 {
1154 tree bitfield_type;
1157 {
1160 }
1161 }
1164 /* Tell convert_like_real to set LOOKUP_PREFER_RVALUE. */
1166 }
1168 /* Allow conversion between `__complex__' data types. */
1170 {
1171 /* The standard conversion sequence to convert FROM to TO is
1172 the standard conversion sequence to perform componentwise
1173 conversion. */
1176 complain);
1179 {
1182 }
1183 else
1187 }
1190 {
1194 }
1196 /* [conv.ptr]
1197 A null pointer constant can be converted to a pointer type; ... A
1198 null pointer constant of integral type can be converted to an
1199 rvalue of type std::nullptr_t. */
1207 {
1208 /* For backwards brain damage compatibility, allow interconversion of
1209 pointers and integers with a pedwarn. */
1212 }
1214 {
1215 /* For backwards brain damage compatibility, allow interconversion of
1216 enums and integers with a pedwarn. */
1219 }
1222 {
1223 tree to_pointee;
1224 tree from_pointee;
1227 {
1231 /* Since this is the target of a pointer, it can't have function
1232 qualifiers, so any TYPE_QUALS must be for attributes const or
1233 noreturn. Strip them. */
1240 }
1241 else
1242 {
1245 }
1249 to_pointee))
1250 ;
1254 {
1256 /* Don't try to apply restrict to void. */
1261 }
1263 {
1270 && (same_type_ignoring_top_level_qualifiers_p
1272 {
1275 }
1276 else
1278 }
1281 /* [conv.ptr]
1283 An rvalue of type "pointer to cv D," where D is a
1284 class type, can be converted to an rvalue of type
1285 "pointer to cv B," where B is a base class (clause
1286 _class.derived_) of D. If B is an inaccessible
1287 (clause _class.access_) or ambiguous
1288 (_class.member.lookup_) base class of D, a program
1289 that necessitates this conversion is ill-formed.
1290 Therefore, we use DERIVED_FROM_P, and do not check
1291 access or uniqueness. */
1293 {
1294 from_pointee
1300 }
1305 /* In a C-style cast, we ignore CV-qualification because we
1306 are allowed to perform a static_cast followed by a
1307 const_cast. */
1312 /* converting from string constant to char *. */
1316 /* Allow conversions among compatible ObjC pointer types (base
1317 conversions have been already handled above). */
1322 {
1325 }
1326 else
1330 }
1332 {
1346 else
1350 {
1352 tbase,
1358 }
1361 }
1363 {
1364 /* [conv.bool]
1366 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1367 to member type can be converted to a prvalue of type bool. ...
1368 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1369 std::nullptr_t can be converted to a prvalue of type bool; */
1375 {
1386 }
1389 }
1390 /* We don't check for ENUMERAL_TYPE here because there are no standard
1391 conversions to enum type. */
1392 /* As an extension, allow conversion to complex type. */
1394 {
1401 /* Give this a better rank if it's a promotion. */
1405 }
1411 {
1415 /* The derived-to-base conversion indicates the initialization
1416 of a parameter with base type from an object of a derived
1417 type. A temporary object is created to hold the result of
1418 the conversion unless we're binding directly to a reference. */
1420 }
1421 else
1428 }
1430 /* Returns nonzero if T1 is reference-related to T2. */
1432 bool
1434 {
1441 /* [dcl.init.ref]
1443 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1444 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1445 of T2. */
1449 }
1451 /* Returns nonzero if T1 is reference-compatible with T2. */
1453 static bool
1455 {
1456 /* [dcl.init.ref]
1458 "cv1 T1" is reference compatible with "cv2 T2" if
1459 * T1 is reference-related to T2 or
1460 * T2 is "noexcept function" and T1 is "function", where the
1461 function types are otherwise the same,
1462 and cv1 is the same cv-qualification as, or greater cv-qualification
1463 than, cv2. */
1467 }
1469 /* A reference of the indicated TYPE is being bound directly to the
1470 expression represented by the implicit conversion sequence CONV.
1471 Return a conversion sequence for this binding. */
1475 {
1476 tree t;
1483 /* [over.ics.rank]
1485 When a parameter of reference type binds directly
1486 (_dcl.init.ref_) to an argument expression, the implicit
1487 conversion sequence is the identity conversion, unless the
1488 argument expression has a type that is a derived class of the
1489 parameter type, in which case the implicit conversion sequence is
1490 a derived-to-base Conversion.
1492 If the parameter binds directly to the result of applying a
1493 conversion function to the argument expression, the implicit
1494 conversion sequence is a user-defined conversion sequence
1495 (_over.ics.user_), with the second standard conversion sequence
1496 either an identity conversion or, if the conversion function
1497 returns an entity of a type that is a derived class of the
1498 parameter type, a derived-to-base conversion. */
1500 {
1501 /* Represent the derived-to-base conversion. */
1503 /* We will actually be binding to the base-class subobject in
1504 the derived class, so we mark this conversion appropriately.
1505 That way, convert_like knows not to generate a temporary. */
1507 }
1509 }
1511 /* Returns the conversion path from type FROM to reference type TO for
1512 purposes of reference binding. For lvalue binding, either pass a
1513 reference type to FROM or an lvalue expression to EXPR. If the
1514 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1515 the conversion returned. If C_CAST_P is true, this
1516 conversion is coming from a C-style cast. */
1520 tsubst_flags_t complain)
1521 {
1525 tree tfrom;
1528 cp_lvalue_kind gl_kind;
1532 {
1537 }
1540 {
1542 /* DR 1288: Otherwise, if the initializer list has a single element
1543 of type E and ... [T's] referenced type is reference-related to E,
1544 the object or reference is initialized from that element... */
1546 {
1552 {
1556 }
1557 }
1558 /* Otherwise, if T is a reference type, a prvalue temporary of the
1559 type referenced by T is copy-list-initialized or
1560 direct-list-initialized, depending on the kind of initialization
1561 for the reference, and the reference is bound to that temporary. */
1564 skip:;
1565 }
1568 {
1573 else
1575 }
1581 else
1584 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1589 /* Same mask as real_lvalue_p. */
1596 /* Figure out whether or not the types are reference-related and
1597 reference compatible. We have to do this after stripping
1598 references from FROM. */
1600 /* If this is a C cast, first convert to an appropriately qualified
1601 type, so that we can later do a const_cast to the desired type. */
1607 /* Directly bind reference when target expression's type is compatible with
1608 the reference and expression is an lvalue. In DR391, the wording in
1609 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1610 const and rvalue references to rvalues of compatible class type.
1611 We should also do direct bindings for non-class xvalues. */
1613 {
1614 /* [dcl.init.ref]
1616 If the initializer expression
1618 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1619 is reference-compatible with "cv2 T2,"
1621 the reference is bound directly to the initializer expression
1622 lvalue.
1624 [...]
1625 If the initializer expression is an rvalue, with T2 a class type,
1626 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1627 is bound to the object represented by the rvalue or to a sub-object
1628 within that object. */
1634 /* Handle rvalue reference to function properly. */
1635 conv->rvaluedness_matches_p
1637 else
1638 conv->rvaluedness_matches_p
1643 /* For the purposes of overload resolution, we ignore the fact
1644 this expression is a bitfield or packed field. (In particular,
1645 [over.ics.ref] says specifically that a function with a
1646 non-const reference parameter is viable even if the
1647 argument is a bitfield.)
1649 However, when we actually call the function we must create
1650 a temporary to which to bind the reference. If the
1651 reference is volatile, or isn't const, then we cannot make
1652 a temporary, so we just issue an error when the conversion
1653 actually occurs. */
1656 /* Don't allow binding of lvalues (other than function lvalues) to
1657 rvalue references. */
1662 /* Nor the reverse. */
1673 }
1674 /* [class.conv.fct] A conversion function is never used to convert a
1675 (possibly cv-qualified) object to the (possibly cv-qualified) same
1676 object type (or a reference to it), to a (possibly cv-qualified) base
1677 class of that type (or a reference to it).... */
1680 {
1681 /* [dcl.init.ref]
1683 If the initializer expression
1685 -- has a class type (i.e., T2 is a class type) can be
1686 implicitly converted to an lvalue of type "cv3 T3," where
1687 "cv1 T1" is reference-compatible with "cv3 T3". (this
1688 conversion is selected by enumerating the applicable
1689 conversion functions (_over.match.ref_) and choosing the
1690 best one through overload resolution. (_over.match_).
1692 the reference is bound to the lvalue result of the conversion
1693 in the second case. */
1695 complain);
1698 }
1700 /* From this point on, we conceptually need temporaries, even if we
1701 elide them. Only the cases above are "direct bindings". */
1705 /* [over.ics.rank]
1707 When a parameter of reference type is not bound directly to an
1708 argument expression, the conversion sequence is the one required
1709 to convert the argument expression to the underlying type of the
1710 reference according to _over.best.ics_. Conceptually, this
1711 conversion sequence corresponds to copy-initializing a temporary
1712 of the underlying type with the argument expression. Any
1713 difference in top-level cv-qualification is subsumed by the
1714 initialization itself and does not constitute a conversion. */
1716 /* [dcl.init.ref]
1718 Otherwise, the reference shall be an lvalue reference to a
1719 non-volatile const type, or the reference shall be an rvalue
1720 reference.
1722 We try below to treat this as a bad conversion to improve diagnostics,
1723 but if TO is an incomplete class, we need to reject this conversion
1724 now to avoid unnecessary instantiation. */
1729 /* We're generating a temporary now, but don't bind any more in the
1730 conversion (specifically, don't slice the temporary returned by a
1731 conversion operator). */
1734 /* Core issue 899: When [copy-]initializing a temporary to be bound
1735 to the first parameter of a copy constructor (12.8) called with
1736 a single argument in the context of direct-initialization,
1737 explicit conversion functions are also considered.
1739 So don't set LOOKUP_ONLYCONVERTING in that case. */
1750 {
1751 /* If initializing the temporary used a conversion function,
1752 recalculate the second conversion sequence. */
1756 {
1759 conversion *new_second
1765 }
1766 }
1769 /* This reference binding, unlike those above, requires the
1770 creation of a temporary. */
1774 /* [dcl.init.ref]
1776 Otherwise, the reference shall be an lvalue reference to a
1777 non-volatile const type, or the reference shall be an rvalue
1778 reference. */
1782 /* [dcl.init.ref]
1784 Otherwise, a temporary of type "cv1 T1" is created and
1785 initialized from the initializer expression using the rules for a
1786 non-reference copy initialization. If T1 is reference-related to
1787 T2, cv1 must be the same cv-qualification as, or greater
1788 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1793 }
1795 /* Returns the implicit conversion sequence (see [over.ics]) from type
1796 FROM to type TO. The optional expression EXPR may affect the
1797 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1798 true, this conversion is coming from a C-style cast. */
1803 {
1810 /* Other flags only apply to the primary function in overload
1811 resolution, or after we've chosen one. */
1816 /* FIXME: actually we don't want warnings either, but we can't just
1817 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1818 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1819 We really ought not to issue that warning until we've committed
1820 to that conversion. */
1823 /* Call reshape_init early to remove redundant braces. */
1828 {
1833 }
1837 else
1844 {
1848 /* As an extension, allow list-initialization of _Complex. */
1850 {
1854 }
1856 /* Allow conversion from an initializer-list with one element to a
1857 scalar type. */
1859 {
1861 tree elt;
1867 else
1873 {
1876 /* Too many levels of braces, i.e. '{{1}}'. */
1879 }
1880 }
1883 }
1889 {
1899 {
1903 {
1904 /* "If C is not an initializer-list constructor and the
1905 initializer list has a single element of type cv U, where U is
1906 X or a class derived from X, the implicit conversion sequence
1907 has Exact Match rank if U is X, or Conversion rank if U is
1908 derived from X." */
1914 }
1916 }
1918 /* We used to try to bind a reference to a temporary here, but that
1919 is now handled after the recursive call to this function at the end
1920 of reference_binding. */
1922 }
1925 }
1927 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1928 functions. ARGS will not be changed until a single candidate is
1929 selected. */
1938 {
1956 }
1958 /* Return the number of remaining arguments in the parameter list
1959 beginning with ARG. */
1961 int
1963 {
1968 n++;
1971 }
1973 /* Create an overload candidate for the function or method FN called
1974 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1975 FLAGS is passed on to implicit_conversion.
1977 This does not change ARGS.
1979 CTYPE, if non-NULL, is the type we want to pretend this function
1980 comes from for purposes of overload resolution. */
1987 tsubst_flags_t complain)
1988 {
1992 tree parmnode;
1998 /* At this point we should not see any functions which haven't been
1999 explicitly declared, except for friend functions which will have
2000 been found using argument dependent lookup. */
2003 /* The `this', `in_chrg' and VTT arguments to constructors are not
2004 considered in overload resolution. */
2006 {
2008 /* Bring back parameters omitted from an inherited ctor. */
2010 else
2014 {
2017 }
2018 }
2019 else
2025 /* 13.3.2 - Viable functions [over.match.viable]
2026 First, to be a viable function, a candidate function shall have enough
2027 parameters to agree in number with the arguments in the list.
2029 We need to check this first; otherwise, checking the ICSes might cause
2030 us to produce an ill-formed template instantiation. */
2034 {
2038 }
2042 {
2046 }
2048 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2049 parameter of type "reference to cv C" (including such a constructor
2050 instantiated from a template) is excluded from the set of candidate
2051 functions when used to construct an object of type D with an argument list
2052 containing a single argument if C is reference-related to D. */
2054 && flag_new_inheriting_ctors
2056 {
2062 {
2065 }
2066 }
2068 /* Second, for a function to be viable, its constraints must be
2069 satisfied. */
2072 {
2075 }
2077 /* When looking for a function from a subobject from an implicit
2078 copy/move constructor/operator=, don't consider anything that takes (a
2079 reference to) an unrelated type. See c++/44909 and core 1092. */
2081 {
2087 else
2090 {
2093 ctype))
2095 }
2097 /* This only applies at the top level. */
2099 }
2104 /* Third, for F to be a viable function, there shall exist for each
2105 argument an implicit conversion sequence that converts that argument
2106 to the corresponding parameter of F. */
2111 {
2113 tree arg;
2122 else
2131 {
2137 /* The type of the implicit object parameter ('this') for
2138 overload resolution is not always the same as for the
2139 function itself; conversion functions are considered to
2140 be members of the class being converted, and functions
2141 introduced by a using-declaration are considered to be
2142 members of the class that uses them.
2144 Since build_over_call ignores the ICS for the `this'
2145 parameter, we can just change the parm type. */
2147 {
2148 parmtype = cp_build_qualified_type
2151 {
2152 /* If the function has a ref-qualifier, the implicit
2153 object parameter has reference type. */
2156 /* The special handling of 'this' conversions in compare_ics
2157 does not apply if there is a ref-qualifier. */
2159 }
2160 else
2161 {
2165 }
2166 }
2168 /* Core issue 899: When [copy-]initializing a temporary to be bound
2169 to the first parameter of a copy constructor (12.8) called with
2170 a single argument in the context of direct-initialization,
2171 explicit conversion functions are also considered.
2173 So set LOOKUP_COPY_PARM to let reference_binding know that
2174 it's being called in that context. We generalize the above
2175 to handle move constructors and template constructors as well;
2176 the standardese should soon be updated similarly. */
2180 && (same_type_ignoring_top_level_qualifiers_p
2182 {
2185 /* We allow user-defined conversions within init-lists, but
2186 don't list-initialize the copy parm, as that would mean
2187 using two levels of braces for the same type. */
2191 }
2192 else
2198 }
2199 else
2200 {
2204 }
2211 {
2215 }
2218 {
2221 }
2222 }
2224 out:
2227 }
2229 /* Create an overload candidate for the conversion function FN which will
2230 be invoked for expression OBJ, producing a pointer-to-function which
2231 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2232 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2233 passed on to implicit_conversion.
2235 Actually, we don't really care about FN; we care about the type it
2236 converts to. There may be multiple conversion functions that will
2237 convert to that type, and we rely on build_user_type_conversion_1 to
2238 choose the best one; so when we create our candidate, we record the type
2239 instead of the function. */
2245 tsubst_flags_t complain)
2246 {
2264 /* Don't bother looking up the same type twice. */
2269 {
2275 else
2280 {
2284 }
2288 {
2292 }
2293 else
2294 {
2298 }
2305 {
2308 }
2315 }
2319 {
2323 }
2327 }
2329 static void
2333 {
2347 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2348 conversion ops are allowed. We handle that here by just checking for
2349 boolean_type_node because other operators don't ask for it. COND_EXPR
2350 also does contextual conversion to bool for the first operand, but we
2351 handle that in build_conditional_expr, and type1 here is operand 2. */
2356 {
2363 {
2365 /* We need something for printing the candidate. */
2369 }
2371 {
2375 }
2377 }
2379 /* For COND_EXPR we rearranged the arguments; undo that now. */
2381 {
2386 complain);
2389 else
2390 {
2393 boolean_type_node);
2394 }
2395 }
2402 }
2404 static bool
2406 {
2408 }
2410 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2412 static bool
2414 {
2415 /* [over.built]
2417 In this section, the term promoted integral type is used to refer
2418 to those integral types which are preserved by integral promotion
2419 (including e.g. int and long but excluding e.g. char).
2420 Similarly, the term promoted arithmetic type refers to promoted
2421 integral types plus floating types. */
2425 }
2427 /* Create any builtin operator overload candidates for the operator in
2428 question given the converted operand types TYPE1 and TYPE2. The other
2429 args are passed through from add_builtin_candidates to
2430 build_builtin_candidate.
2432 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2433 If CODE is requires candidates operands of the same type of the kind
2434 of which TYPE1 and TYPE2 are, we add both candidates
2435 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2437 static void
2441 tsubst_flags_t complain)
2442 {
2444 {
2452 }
2455 {
2457 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2458 and VQ is either volatile or empty, there exist candidate operator
2459 functions of the form
2460 VQ T& operator++(VQ T&);
2461 T operator++(VQ T&, int);
2462 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2463 type other than bool, and VQ is either volatile or empty, there exist
2464 candidate operator functions of the form
2465 VQ T& operator--(VQ T&);
2466 T operator--(VQ T&, int);
2467 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2468 complete object type, and VQ is either volatile or empty, there exist
2469 candidate operator functions of the form
2470 T*VQ& operator++(T*VQ&);
2471 T*VQ& operator--(T*VQ&);
2472 T* operator++(T*VQ&, int);
2473 T* operator--(T*VQ&, int); */
2479 /* FALLTHRU */
2483 {
2486 }
2489 /* 7 For every cv-qualified or cv-unqualified object type T, there
2490 exist candidate operator functions of the form
2492 T& operator*(T*);
2494 8 For every function type T, there exist candidate operator functions of
2495 the form
2496 T& operator*(T*); */
2505 /* 9 For every type T, there exist candidate operator functions of the form
2506 T* operator+(T*);
2508 10For every promoted arithmetic type T, there exist candidate operator
2509 functions of the form
2510 T operator+(T);
2511 T operator-(T); */
2516 /* FALLTHRU */
2522 /* 11For every promoted integral type T, there exist candidate operator
2523 functions of the form
2524 T operator~(T); */
2531 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2532 is the same type as C2 or is a derived class of C2, T is a complete
2533 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2534 there exist candidate operator functions of the form
2535 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2536 where CV12 is the union of CV1 and CV2. */
2540 {
2548 }
2551 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2552 didate operator functions of the form
2553 LR operator*(L, R);
2554 LR operator/(L, R);
2555 LR operator+(L, R);
2556 LR operator-(L, R);
2557 bool operator<(L, R);
2558 bool operator>(L, R);
2559 bool operator<=(L, R);
2560 bool operator>=(L, R);
2561 bool operator==(L, R);
2562 bool operator!=(L, R);
2563 where LR is the result of the usual arithmetic conversions between
2564 types L and R.
2566 14For every pair of types T and I, where T is a cv-qualified or cv-
2567 unqualified complete object type and I is a promoted integral type,
2568 there exist candidate operator functions of the form
2569 T* operator+(T*, I);
2570 T& operator[](T*, I);
2571 T* operator-(T*, I);
2572 T* operator+(I, T*);
2573 T& operator[](I, T*);
2575 15For every T, where T is a pointer to complete object type, there exist
2576 candidate operator functions of the form112)
2577 ptrdiff_t operator-(T, T);
2579 16For every pointer or enumeration type T, there exist candidate operator
2580 functions of the form
2581 bool operator<(T, T);
2582 bool operator>(T, T);
2583 bool operator<=(T, T);
2584 bool operator>=(T, T);
2585 bool operator==(T, T);
2586 bool operator!=(T, T);
2588 17For every pointer to member type T, there exist candidate operator
2589 functions of the form
2590 bool operator==(T, T);
2591 bool operator!=(T, T); */
2598 {
2601 }
2602 /* FALLTHRU */
2615 {
2618 }
2620 {
2623 }
2624 /* Fall through. */
2640 {
2643 }
2646 {
2649 }
2655 /* FALLTHRU */
2658 {
2661 }
2663 {
2666 }
2669 /* 18For every pair of promoted integral types L and R, there exist candi-
2670 date operator functions of the form
2671 LR operator%(L, R);
2672 LR operator&(L, R);
2673 LR operator^(L, R);
2674 LR operator|(L, R);
2675 L operator<<(L, R);
2676 L operator>>(L, R);
2677 where LR is the result of the usual arithmetic conversions between
2678 types L and R. */
2686 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2690 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2691 type, VQ is either volatile or empty, and R is a promoted arithmetic
2692 type, there exist candidate operator functions of the form
2693 VQ L& operator=(VQ L&, R);
2694 VQ L& operator*=(VQ L&, R);
2695 VQ L& operator/=(VQ L&, R);
2696 VQ L& operator+=(VQ L&, R);
2697 VQ L& operator-=(VQ L&, R);
2699 20For every pair T, VQ), where T is any type and VQ is either volatile
2700 or empty, there exist candidate operator functions of the form
2701 T*VQ& operator=(T*VQ&, T*);
2703 21For every pair T, VQ), where T is a pointer to member type and VQ is
2704 either volatile or empty, there exist candidate operator functions of
2705 the form
2706 VQ T& operator=(VQ T&, T);
2708 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2709 unqualified complete object type, VQ is either volatile or empty, and
2710 I is a promoted integral type, there exist candidate operator func-
2711 tions of the form
2712 T*VQ& operator+=(T*VQ&, I);
2713 T*VQ& operator-=(T*VQ&, I);
2715 23For every triple L, VQ, R), where L is an integral or enumeration
2716 type, VQ is either volatile or empty, and R is a promoted integral
2717 type, there exist candidate operator functions of the form
2719 VQ L& operator%=(VQ L&, R);
2720 VQ L& operator<<=(VQ L&, R);
2721 VQ L& operator>>=(VQ L&, R);
2722 VQ L& operator&=(VQ L&, R);
2723 VQ L& operator^=(VQ L&, R);
2724 VQ L& operator|=(VQ L&, R); */
2728 {
2732 {
2735 }
2736 /* FALLTHRU */
2749 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2762 {
2765 }
2770 }
2775 /* [over.built]
2777 For every pair of promoted arithmetic types L and R, there
2778 exist candidate operator functions of the form
2780 LR operator?(bool, L, R);
2782 where LR is the result of the usual arithmetic conversions
2783 between types L and R.
2785 For every type T, where T is a pointer or pointer-to-member
2786 type, there exist candidate operator functions of the form T
2787 operator?(bool, T, T); */
2791 /* That's OK. */
2794 /* Otherwise, the types should be pointers. */
2798 /* We don't check that the two types are the same; the logic
2799 below will actually create two candidates; one in which both
2800 parameter types are TYPE1, and one in which both parameter
2801 types are TYPE2. */
2812 }
2814 /* Make sure we don't create builtin candidates with dependent types. */
2818 {
2819 /* Try to recover if one of the types is non-dependent. But if
2820 there's only one type, there's nothing we can do. */
2823 /* And we lose if both are dependent. */
2826 /* Or if they have different forms. */
2834 }
2836 /* If we're dealing with two pointer types or two enumeral types,
2837 we need candidates for both of them. */
2846 {
2848 {
2850 error_mark_node,
2851 error_mark_node,
2852 CPO_CONVERSION,
2853 tf_none);
2855 {
2856 build_builtin_candidate
2860 }
2861 }
2863 build_builtin_candidate
2865 build_builtin_candidate
2868 }
2870 build_builtin_candidate
2872 }
2874 tree
2876 {
2882 }
2884 /* There are three conditions of builtin candidates:
2886 1) bool-taking candidates. These are the same regardless of the input.
2887 2) pointer-pair taking candidates. These are generated for each type
2888 one of the input types converts to.
2889 3) arithmetic candidates. According to the standard, we should generate
2890 all of these, but I'm trying not to...
2892 Here we generate a superset of the possible candidates for this particular
2893 case. That is a subset of the full set the standard defines, plus some
2894 other cases which the standard disallows. add_builtin_candidate will
2895 filter out the invalid set. */
2897 static void
2901 {
2905 /* TYPES[i] is the set of possible builtin-operator parameter types
2906 we will consider for the Ith argument. */
2911 {
2914 else
2916 }
2919 {
2920 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2921 and VQ is either volatile or empty, there exist candidate operator
2922 functions of the form
2923 VQ T& operator++(VQ T&); */
2933 /* 24There also exist candidate operator functions of the form
2934 bool operator!(bool);
2935 bool operator&&(bool, bool);
2936 bool operator||(bool, bool); */
2939 build_builtin_candidate
2946 build_builtin_candidate
2964 /* Fall through. */
2968 }
2974 {
2976 ;
2978 {
2979 tree convs;
2987 {
2992 }
2998 {
3011 {
3017 }
3021 }
3022 }
3023 else
3024 {
3029 {
3035 }
3037 }
3038 }
3040 /* Run through the possible parameter types of both arguments,
3041 creating candidates with those parameter types. */
3043 {
3045 tree u;
3049 add_builtin_candidate
3052 else
3053 add_builtin_candidate
3056 }
3060 }
3063 /* If TMPL can be successfully instantiated as indicated by
3064 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3066 TMPL is the template. EXPLICIT_TARGS are any explicit template
3067 arguments. ARGLIST is the arguments provided at the call-site.
3068 This does not change ARGLIST. The RETURN_TYPE is the desired type
3069 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3070 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3071 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3079 tsubst_flags_t complain)
3080 {
3090 tree arg;
3092 tree fn;
3096 /* We don't do deduction on the in-charge parameter, the VTT
3097 parameter or 'this'. */
3099 {
3103 /* We're deducing for a call to the result of a template conversion
3105 else
3107 }
3112 {
3115 else
3117 }
3125 {
3126 /* 12.8/6 says, "A declaration of a constructor for a class X is
3127 ill-formed if its first parameter is of type (optionally cv-qualified)
3128 X and either there are no other parameters or else all other
3129 parameters have default arguments. A member function template is never
3130 instantiated to produce such a constructor signature."
3132 So if we're trying to copy an object of the containing class, don't
3133 consider a template constructor that has a first parameter type that
3134 is just a template parameter, as we would deduce a signature that we
3135 would then reject in the code below. */
3137 {
3142 {
3146 }
3147 }
3148 }
3155 {
3158 }
3162 {
3165 }
3170 args_without_in_chrg,
3171 nargs_without_in_chrg,
3176 {
3177 /* Don't repeat unification later if it already resulted in errors. */
3181 nargs_without_in_chrg,
3183 else
3186 }
3189 {
3192 ctype))
3193 {
3194 /* We're trying to produce a constructor with a prohibited signature,
3195 as discussed above; handle here any cases we didn't catch then,
3196 such as X(X<T>). */
3199 }
3200 }
3203 /* Aha, this is a conversion function. */
3206 else
3211 /* This situation can occur if a member template of a template
3212 class is specialized. Then, instantiate_template might return
3213 an instantiation of the specialization, in which case the
3214 DECL_TI_TEMPLATE field will point at the original
3215 specialization. For example:
3217 template <class T> struct S { template <class U> void f(U);
3218 template <> void f(int) {}; };
3219 S<double> sd;
3220 sd.f(3);
3222 Here, TMPL will be template <class U> S<double>::f(U).
3223 And, instantiate template will give us the specialization
3224 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3225 for this will point at template <class T> template <> S<T>::f(int),
3226 so that we can find the definition. For the purposes of
3227 overload resolution, however, we want the original TMPL. */
3229 else
3234 fail:
3237 }
3246 {
3247 return
3252 }
3254 /* Create an overload candidate for the conversion function template TMPL,
3255 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3256 pointer-to-function which will in turn be called with the argument list
3257 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3258 passed on to implicit_conversion. */
3262 tree obj,
3266 {
3267 /* Making this work broke PR 71117, so until the committee resolves core
3268 issue 2189, let's disable this candidate if there are any viable call
3269 operators. */
3273 return
3277 complain);
3278 }
3280 /* The CANDS are the set of candidates that were considered for
3281 overload resolution. Return the set of viable candidates, or CANDS
3282 if none are viable. If any of the candidates were viable, set
3283 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3284 considered viable only if it is strictly viable. */
3290 {
3296 /* Be strict inside templates, since build_over_call won't actually
3297 do the conversions to get pedwarns. */
3307 {
3311 {
3312 /* Be strict in the presence of a viable candidate. Also if
3313 there are template candidates, so that we get deduction errors
3314 for them instead of silently preferring a bad conversion. */
3317 {
3318 /* Put any spliced near matches back onto the main list so
3319 that we see them if there is no strict match. */
3325 }
3326 }
3329 {
3337 }
3338 else
3340 }
3343 }
3345 static bool
3347 {
3352 }
3354 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3355 words, it is about to become the "this" pointer for a member
3356 function call. Take the address of the object. */
3358 static tree
3360 {
3361 /* In a template, we are only concerned about the type of the
3362 expression, so we can take a shortcut. */
3367 }
3369 /* Returns true iff functions are equivalent. Equivalent functions are
3370 not '==' only if one is a function-local extern function or if
3371 both are extern "C". */
3375 {
3384 }
3386 /* Print information about a candidate being rejected due to INFO. */
3388 static void
3390 {
3395 {
3396 /* Conversion of implicit `this' argument failed. */
3398 /* A bad conversion for 'this' must be discarding cv-quals. */
3401 from);
3402 else
3406 }
3408 {
3413 tf_warning_or_error);
3414 }
3416 /* Conversion of conversion function return value failed. */
3419 else
3422 }
3424 /* Print information about a candidate with WANT parameters and we found
3425 HAVE. */
3427 static void
3429 {
3434 }
3436 /* Print information about one overload candidate CANDIDATE. MSGSTR
3437 is the text to print before the candidate itself.
3439 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3440 to have been run through gettext by the caller. This wart makes
3441 life simpler in print_z_candidates and for the translators. */
3443 static void
3446 {
3456 {
3467 else
3470 }
3477 else
3480 {
3483 }
3484 /* Give the user some information about why this candidate failed. */
3486 {
3490 {
3503 "cannot be converted to %qT with a qualification "
3509 "conversion function specialization to %qT is not an "
3514 /* We use template_unification_error_rejection if unification caused
3515 actual non-SFINAE errors, in which case we don't need to repeat
3516 them here. */
3518 {
3522 }
3523 /* Re-run template unification with diagnostics. */
3527 (make_tree_vec
3538 " a constructor taking a single argument of its own "
3542 {
3546 }
3550 "initialization from an expression of the same or derived "
3555 /* This candidate didn't have any issues or we failed to
3556 handle a particular code. Either way... */
3558 }
3559 }
3560 }
3562 static void
3564 {
3571 /* Remove non-viable deleted candidates. */
3574 {
3579 else
3581 }
3582 /* ...if there are any non-deleted ones. */
3586 /* There may be duplicates in the set of candidates. We put off
3587 checking this condition as long as possible, since we have no way
3588 to eliminate duplicates from a set of functions in less than n^2
3589 time. Now we are about to emit an error message, so it is more
3590 permissible to go slowly. */
3592 {
3594 /* Skip builtin candidates and conversion functions. */
3599 {
3603 else
3605 }
3606 }
3610 }
3612 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3613 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3614 the result of the conversion function to convert it to the final
3615 desired type. Merge the two sequences into a single sequence,
3616 and return the merged sequence. */
3620 {
3626 /* Find the end of the second conversion sequence. */
3628 {
3629 /* The entire sequence is a user-conversion sequence. */
3633 }
3635 /* Replace the identity conversion with the user conversion
3636 sequence. */
3640 }
3642 /* Handle overload resolution for initializing an object of class type from
3643 an initializer list. First we look for a suitable constructor that
3644 takes a std::initializer_list; if we don't find one, we then look for a
3645 non-list constructor.
3647 Parameters are as for add_candidates, except that the arguments are in
3648 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3649 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3651 static void
3658 tsubst_flags_t complain)
3659 {
3662 /* We're looking for a ctor for list-initialization. */
3664 /* And we don't allow narrowing conversions. We also use this flag to
3665 avoid the copy constructor call for copy-list-initialization. */
3671 /* Always use the default constructor if the list is empty (DR 990). */
3674 ;
3675 /* If the class has a list ctor, try passing the list as a single
3676 argument first, but only consider list ctors. */
3678 {
3685 }
3687 /* Expand the CONSTRUCTOR into a new argument vec. */
3695 /* We aren't looking for list-ctors anymore. */
3697 /* We allow more user-defined conversions within an init-list. */
3703 }
3705 /* Returns the best overload candidate to perform the requested
3706 conversion. This function is used for three the overloading situations
3707 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3708 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3709 per [dcl.init.ref], so we ignore temporary bindings. */
3713 tsubst_flags_t complain)
3714 {
3716 tree fromtype;
3730 /* We represent conversion within a hierarchy using RVALUE_CONV and
3731 BASE_CONV, as specified by [over.best.ics]; these become plain
3732 constructor calls, as specified in [dcl.init]. */
3737 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3738 creating a garbage BASELINK; constructors can't be inherited. */
3741 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3742 a single element. For now, let's handle constructors as before and also
3743 consider conversion operators from the element. */
3750 {
3755 {
3756 /* [class.conv.fct] A conversion function is never used to
3757 convert a (possibly cv-qualified) object to the (possibly
3758 cv-qualified) same object type (or a reference to it), to a
3759 (possibly cv-qualified) base class of that type (or a
3760 reference to it)... */
3761 }
3762 else
3764 }
3771 /* It's OK to bind a temporary for converting constructor arguments, but
3772 not in converting the return value of a conversion operator. */
3778 {
3783 /* We should never try to call the abstract or base constructor
3784 from here. */
3790 {
3791 /* List-initialization. */
3795 }
3796 else
3797 {
3801 }
3804 {
3807 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3808 set, then this is copy-initialization. In that case, "The
3809 result of the call is then used to direct-initialize the
3810 object that is the destination of the copy-initialization."
3811 [dcl.init]
3813 We represent this in the conversion sequence with an
3814 rvalue conversion, which means a constructor call. */
3817 cand->second_conv
3819 }
3820 }
3823 {
3825 /* FIXME see above about C++17. */
3827 else
3829 }
3832 {
3836 /* If we are called to convert to a reference type, we are trying to
3837 find a direct binding, so don't even consider temporaries. If
3838 we don't find a direct binding, the caller will try again to
3839 look for a temporary binding. */
3850 {
3852 conversion *ics
3854 rettype,
3857 complain);
3859 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3860 copy-initialization. In that case, "The result of the
3861 call is then used to direct-initialize the object that is
3862 the destination of the copy-initialization." [dcl.init]
3864 We represent this in the conversion sequence with an
3865 rvalue conversion, which means a constructor call. But
3866 don't add a second rvalue conversion if there's already
3867 one there. Which there really shouldn't be, but it's
3868 harmless since we'd add it here anyway. */
3876 {
3880 }
3883 {
3884 /* 13.3.1.5: For direct-initialization, those explicit
3885 conversion functions that are not hidden within S and
3886 yield type T or a type that can be converted to type T
3887 with a qualification conversion (4.4) are also candidate
3888 functions. */
3889 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3890 I've raised this issue with the committee. --jason 9/2011 */
3893 }
3895 {
3897 cand->reason
3900 }
3903 {
3904 /* 13.3.3.1.2: If the user-defined conversion is specified by
3905 a specialization of a conversion function template, the
3906 second standard conversion sequence shall have exact match
3907 rank. */
3910 }
3911 }
3912 }
3916 {
3920 }
3924 {
3926 {
3930 }
3937 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3938 ambiguous conversion is no worse than another user-defined
3939 conversion. */
3942 }
3944 tree convtype;
3948 /* DR 5: [in the first step of copy-initialization]...if the function
3949 is a constructor, the call initializes a temporary of the
3950 cv-unqualified version of the destination type. */
3952 else
3954 /* Build the user conversion sequence. */
3955 conv = build_conv
3957 convtype,
3963 /* Remember that this was a list-initialization. */
3967 /* Combine it with the second conversion sequence. */
3972 }
3974 /* Wrapper for above. */
3976 tree
3978 tsubst_flags_t complain)
3979 {
3981 tree ret;
3987 {
3990 else
3991 {
3994 }
3995 }
3996 else
4001 }
4003 /* Subroutine of convert_nontype_argument.
4005 EXPR is an expression used in a context that requires a converted
4006 constant-expression, such as a template non-type parameter. Do any
4007 necessary conversions (that are permitted for converted
4008 constant-expressions) to convert it to the desired type.
4010 If conversion is successful, returns the converted expression;
4011 otherwise, returns error_mark_node. */
4013 tree
4015 {
4018 tree t;
4024 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4031 /* A converted constant expression of type T is an expression, implicitly
4032 converted to type T, where the converted expression is a constant
4033 expression and the implicit conversion sequence contains only
4035 * user-defined conversions,
4036 * lvalue-to-rvalue conversions (7.1),
4037 * array-to-pointer conversions (7.2),
4038 * function-to-pointer conversions (7.3),
4039 * qualification conversions (7.5),
4040 * integral promotions (7.6),
4041 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4042 * null pointer conversions (7.11) from std::nullptr_t,
4043 * null member pointer conversions (7.12) from std::nullptr_t, and
4044 * function pointer conversions (7.13),
4046 and where the reference binding (if any) binds directly. */
4051 {
4053 {
4054 /* A conversion function is OK. If it isn't constexpr, we'll
4055 complain later that the argument isn't constant. */
4057 /* The lvalue-to-rvalue conversion is OK. */
4059 /* Array-to-pointer and function-to-pointer. */
4061 /* Function pointer conversions. */
4063 /* Qualification conversions. */
4069 {
4075 }
4085 /* Integral promotion or conversion. */
4088 /* Conversion from nullptr to pointer or pointer-to-member. */
4094 /* fall through. */
4099 }
4100 }
4102 /* Avoid confusing convert_nontype_argument by introducing
4103 a redundant conversion to the same reference type. */
4106 {
4110 }
4114 else
4117 /* Free all the conversions we allocated. */
4121 }
4123 /* Do any initial processing on the arguments to a function call. */
4127 {
4129 tree arg;
4132 {
4136 {
4140 }
4143 }
4145 }
4147 /* Perform overload resolution on FN, which is called with the ARGS.
4149 Return the candidate function selected by overload resolution, or
4150 NULL if the event that overload resolution failed. In the case
4151 that overload resolution fails, *CANDIDATES will be the set of
4152 candidates considered, and ANY_VIABLE_P will be set to true or
4153 false to indicate whether or not any of the candidates were
4154 viable.
4156 The ARGS should already have gone through RESOLVE_ARGS before this
4157 function is called. */
4164 {
4166 tree explicit_targs;
4177 /* Check FN. */
4184 {
4188 }
4190 /* Add the various candidate functions. */
4195 LOOKUP_NORMAL,
4201 else
4206 }
4208 /* Print an error message about being unable to build a call to FN with
4209 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4210 be located; CANDIDATES is a possibly empty list of such
4211 functions. */
4213 static void
4216 {
4219 {
4222 }
4231 else
4236 }
4238 /* Return an expression for a call to FN (a namespace-scope function,
4239 or a static member function) with the ARGS. This may change
4240 ARGS. */
4242 tree
4244 tsubst_flags_t complain)
4245 {
4249 tree result;
4252 {
4256 }
4261 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4265 complain);
4268 {
4270 {
4271 // If there is a single (non-viable) function candidate,
4272 // let the error be diagnosed by cp_build_function_call_vec.
4277 // Otherwise, emit notes for non-viable candidates.
4279 }
4281 }
4282 else
4283 {
4285 /* If fn is template_id_expr, the call has explicit template arguments
4286 (e.g. func<int>(5)), communicate this info to build_over_call
4287 through flags so that later we can use it to decide whether to warn
4288 about peculiar null pointer conversion. */
4290 {
4291 /* If overload resolution selects a specialization of a
4292 function concept for non-dependent template arguments,
4293 the expression is true if the constraints are satisfied
4294 and false otherwise.
4296 NOTE: This is an extension of Concepts Lite TS that
4297 allows constraints to be used in expressions. */
4299 {
4305 }
4308 }
4311 }
4313 /* Free all the conversions we allocated. */
4317 }
4319 /* Build a call to a global operator new. FNNAME is the name of the
4320 operator (either "operator new" or "operator new[]") and ARGS are
4321 the arguments provided. This may change ARGS. *SIZE points to the
4322 total number of bytes required by the allocation, and is updated if
4323 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4324 be used. If this function determines that no cookie should be
4325 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4326 is not NULL_TREE, it is evaluated before calculating the final
4327 array size, and if it fails, the array size is replaced with
4328 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4329 is non-NULL, it will be set, upon return, to the allocation
4330 function called. */
4332 tree
4337 {
4339 tree fns;
4346 /* Set to (size_t)-1 if the size check fails. */
4348 {
4354 }
4360 /* Based on:
4362 [expr.new]
4364 If this lookup fails to find the name, or if the allocated type
4365 is not a class type, the allocation function's name is looked
4366 up in the global scope.
4368 we disregard block-scope declarations of "operator new". */
4373 {
4378 /* If no aligned allocation function matches, try again without the
4379 alignment. */
4380 }
4382 /* Figure out what function is being called. */
4385 complain);
4387 /* If no suitable function could be found, issue an error message
4388 and give up. */
4390 {
4394 }
4396 /* If a cookie is required, add some extra space. Whether
4397 or not a cookie is required cannot be determined until
4398 after we know which function was called. */
4400 {
4402 tree arg_types;
4405 /* Skip the size_t parameter. */
4407 /* Check the remaining parameters (if any). */
4411 ptr_type_node))
4413 /* If we need a cookie, adjust the number of bytes allocated. */
4415 {
4416 /* Update the total size. */
4419 {
4420 /* Set to (size_t)-1 if the size check fails. */
4424 }
4425 /* Update the argument list to reflect the adjusted size. */
4427 }
4428 else
4430 }
4432 /* Tell our caller which function we decided to call. */
4436 /* Build the CALL_EXPR. */
4438 }
4440 /* Build a new call to operator(). This may change ARGS. */
4442 static tree
4444 {
4458 {
4460 /* It's no good looking for an overloaded operator() on a
4461 pointer-to-member-function. */
4465 }
4468 {
4472 }
4473 else
4477 {
4481 }
4483 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4487 {
4495 }
4500 {
4508 {
4515 add_template_conv_candidate
4519 else
4523 }
4524 }
4526 /* Be strict here because if we choose a bad conversion candidate, the
4527 errors we get won't mention the call context. */
4530 {
4532 {
4536 }
4538 }
4539 else
4540 {
4543 {
4545 {
4549 }
4551 }
4552 /* Since cand->fn will be a type, not a function, for a conversion
4553 function, we must be careful not to unconditionally look at
4554 DECL_NAME here. */
4558 else
4559 {
4563 else
4567 }
4568 }
4570 /* Free all the conversions we allocated. */
4574 }
4576 /* Wrapper for above. */
4578 tree
4580 {
4581 tree ret;
4586 }
4588 /* Called by op_error to prepare format strings suitable for the error
4589 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4590 and a suffix (controlled by NTYPES). */
4594 {
4604 else
4608 }
4610 static void
4613 {
4618 else
4622 {
4628 else
4640 else
4650 else
4661 else
4671 else
4676 else
4680 else
4685 }
4686 }
4688 /* Return the implicit conversion sequence that could be used to
4689 convert E1 to E2 in [expr.cond]. */
4693 {
4699 /* [expr.cond]
4701 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4702 implicitly converted (clause _conv_) to the type "lvalue reference to
4703 T2", subject to the constraint that in the conversion the
4704 reference must bind directly (_dcl.init.ref_) to an lvalue.
4706 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4707 implicitly converted to the type "rvalue reference to T2", subject to
4708 the constraint that the reference must bind directly. */
4710 {
4713 t1,
4714 e1,
4716 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4718 complain);
4721 }
4723 /* If E2 is a prvalue or if neither of the conversions above can be done
4724 and at least one of the operands has (possibly cv-qualified) class
4725 type: */
4729 /* [expr.cond]
4731 If E1 and E2 have class type, and the underlying class types are
4732 the same or one is a base class of the other: E1 can be converted
4733 to match E2 if the class of T2 is the same type as, or a base
4734 class of, the class of T1, and the cv-qualification of T2 is the
4735 same cv-qualification as, or a greater cv-qualification than, the
4736 cv-qualification of T1. If the conversion is applied, E1 is
4737 changed to an rvalue of type T2 that still refers to the original
4738 source class object (or the appropriate subobject thereof). */
4741 {
4743 {
4748 else
4751 }
4752 else
4754 }
4755 else
4756 /* [expr.cond]
4758 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4759 converted to the type that expression E2 would have if E2 were
4760 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4763 }
4765 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4766 arguments to the conditional expression. */
4768 static tree
4770 tsubst_flags_t complain)
4771 {
4772 tree arg2_type;
4773 tree arg3_type;
4782 /* As a G++ extension, the second argument to the conditional can be
4783 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4784 c'.) If the second operand is omitted, make sure it is
4785 calculated only once. */
4787 {
4795 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4798 else
4800 }
4802 /* If something has already gone wrong, just pass that fact up the
4803 tree. */
4813 {
4816 /* If arg1 is another cond_expr choosing between -1 and 0,
4817 then we can use its comparison. It may help to avoid
4818 additional comparison, produce more accurate diagnostics
4819 and enables folding. */
4829 /* force_rvalue can return error_mark on valid arguments. */
4840 {
4841 /* Rely on the error messages of the scalar version. */
4850 {
4858 }
4862 /* We could pass complain & tf_warning to unsafe_conversion_p,
4863 but the warnings (like Wsign-conversion) have already been
4864 given by the scalar build_conditional_expr_1. We still check
4865 unsafe_conversion_p to forbid truncating long long -> float. */
4867 {
4872 }
4874 {
4879 }
4889 }
4892 {
4898 {
4902 {
4908 }
4910 {
4916 }
4919 }
4920 }
4926 {
4929 "incompatible vector types in conditional expression: "
4933 }
4936 {
4939 }
4941 }
4943 /* [expr.cond]
4945 The first expression is implicitly converted to bool (clause
4946 _conv_). */
4948 LOOKUP_NORMAL);
4952 /* [expr.cond]
4954 If either the second or the third operand has type (possibly
4955 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4956 array-to-pointer (_conv.array_), and function-to-pointer
4957 (_conv.func_) standard conversions are performed on the second
4958 and third operands. */
4962 {
4963 /* Do the conversions. We don't these for `void' type arguments
4964 since it can't have any effect and since decay_conversion
4965 does not handle that case gracefully. */
4973 /* [expr.cond]
4975 One of the following shall hold:
4977 --The second or the third operand (but not both) is a
4978 throw-expression (_except.throw_); the result is of the
4979 type of the other and is an rvalue.
4981 --Both the second and the third operands have type void; the
4982 result is of type void and is an rvalue.
4984 We must avoid calling force_rvalue for expressions of type
4985 "void" because it will complain that their value is being
4986 used. */
4989 {
4991 {
4995 }
4998 }
5001 {
5003 {
5007 }
5010 }
5013 else
5014 {
5016 {
5019 "second operand to the conditional operator "
5020 "is of type %<void%>, but the third operand is "
5022 else
5024 "third operand to the conditional operator "
5025 "is of type %<void%>, but the second operand is "
5027 }
5029 }
5033 }
5034 /* [expr.cond]
5036 Otherwise, if the second and third operand have different types,
5037 and either has (possibly cv-qualified) class type, or if both are
5038 glvalues of the same value category and the same type except for
5039 cv-qualification, an attempt is made to convert each of those operands
5040 to the type of the other. */
5044 arg3_type)
5047 {
5052 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5058 /* [expr.cond]
5060 If both can be converted, or one can be converted but the
5061 conversion is ambiguous, the program is ill-formed. If
5062 neither can be converted, the operands are left unchanged and
5063 further checking is performed as described below. If exactly
5064 one conversion is possible, that conversion is applied to the
5065 chosen operand and the converted operand is used in place of
5066 the original operand for the remainder of this section. */
5071 {
5073 {
5080 else
5082 }
5084 }
5086 {
5090 /* Even if CONV2 is a valid conversion, the result of the
5091 conversion may be invalid. For example, if ARG3 has type
5092 "volatile X", and X does not have a copy constructor
5093 accepting a "volatile X&", then even if ARG2 can be
5094 converted to X, the conversion will fail. */
5098 }
5100 {
5107 }
5109 /* Free all the conversions we allocated. */
5115 /* If, after the conversion, both operands have class type,
5116 treat the cv-qualification of both operands as if it were the
5117 union of the cv-qualification of the operands.
5119 The standard is not clear about what to do in this
5120 circumstance. For example, if the first operand has type
5121 "const X" and the second operand has a user-defined
5122 conversion to "volatile X", what is the type of the second
5123 operand after this step? Making it be "const X" (matching
5124 the first operand) seems wrong, as that discards the
5125 qualification without actually performing a copy. Leaving it
5126 as "volatile X" seems wrong as that will result in the
5127 conditional expression failing altogether, even though,
5128 according to this step, the one operand could be converted to
5129 the type of the other. */
5137 }
5139 /* [expr.cond]
5141 If the second and third operands are glvalues of the same value
5142 category and have the same type, the result is of that type and
5143 value category. */
5147 {
5152 }
5154 /* [expr.cond]
5156 Otherwise, the result is an rvalue. If the second and third
5157 operand do not have the same type, and either has (possibly
5158 cv-qualified) class type, overload resolution is used to
5159 determine the conversions (if any) to be applied to the operands
5160 (_over.match.oper_, _over.built_). */
5164 {
5169 /* Rearrange the arguments so that add_builtin_candidate only has
5170 to know about two args. In build_builtin_candidate, the
5171 arguments are unscrambled. */
5176 COND_EXPR,
5177 NOP_EXPR,
5179 args,
5182 /* [expr.cond]
5184 If the overload resolution fails, the program is
5185 ill-formed. */
5188 {
5193 }
5196 {
5198 {
5201 }
5203 }
5205 /* [expr.cond]
5207 Otherwise, the conversions thus determined are applied, and
5208 the converted operands are used in place of the original
5209 operands for the remainder of this section. */
5218 }
5220 /* [expr.cond]
5222 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5223 and function-to-pointer (_conv.func_) standard conversions are
5224 performed on the second and third operands.
5226 We need to force the lvalue-to-rvalue conversion here for class types,
5227 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5228 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5229 regions. */
5242 /* [expr.cond]
5244 After those conversions, one of the following shall hold:
5246 --The second and third operands have the same type; the result is of
5247 that type. */
5250 /* [expr.cond]
5252 --The second and third operands have arithmetic or enumeration
5253 type; the usual arithmetic conversions are performed to bring
5254 them to a common type, and the result is of that type. */
5259 {
5260 /* In this case, there is always a common type. */
5262 arg3_type);
5265 "implicit conversion from %qH to %qI to "
5267 loc);
5271 {
5275 /* Two enumerators from the same enumeration can have different
5281 }
5288 {
5292 }
5296 }
5297 /* [expr.cond]
5299 --The second and third operands have pointer type, or one has
5300 pointer type and the other is a null pointer constant; pointer
5301 conversions (_conv.ptr_) and qualification conversions
5302 (_conv.qual_) are performed to bring them to their composite
5303 pointer type (_expr.rel_). The result is of the composite
5304 pointer type.
5306 --The second and third operands have pointer to member type, or
5307 one has pointer to member type and the other is a null pointer
5308 constant; pointer to member conversions (_conv.mem_) and
5309 qualification conversions (_conv.qual_) are performed to bring
5310 them to a common type, whose cv-qualification shall match the
5311 cv-qualification of either the second or the third operand.
5312 The result is of the common type. */
5320 {
5323 complain);
5328 }
5331 {
5336 }
5341 valid_operands:
5344 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5345 warn here, because the COND_EXPR will be turned into ARG2. */
5351 /* We can't use result_type below, as fold might have returned a
5352 throw_expr. */
5355 {
5356 /* Expand both sides into the same slot, hopefully the target of
5357 the ?: expression. We used to check for TARGET_EXPRs here,
5358 but now we sometimes wrap them in NOP_EXPRs so the test would
5359 fail. */
5362 /* If this expression is an rvalue, but might be mistaken for an
5363 lvalue, we must add a NON_LVALUE_EXPR. */
5365 }
5366 else
5370 }
5372 /* Wrapper for above. */
5374 tree
5376 tsubst_flags_t complain)
5377 {
5378 tree ret;
5383 }
5385 /* OPERAND is an operand to an expression. Perform necessary steps
5386 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5387 returned. */
5389 static tree
5391 {
5393 {
5396 /* Make sure the template type is instantiated now. */
5398 }
5401 }
5403 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5404 OVERLOAD) to the CANDIDATES, returning an updated list of
5405 CANDIDATES. The ARGS are the arguments provided to the call;
5406 if FIRST_ARG is non-null it is the implicit object argument,
5407 otherwise the first element of ARGS is used if needed. The
5408 EXPLICIT_TARGS are explicit template arguments provided.
5409 TEMPLATE_ONLY is true if only template functions should be
5410 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5411 add_function_candidate. */
5413 static void
5415 tree return_type,
5420 tsubst_flags_t complain)
5421 {
5422 tree ctype;
5426 unification_kind_t strict;
5431 /* Precalculate special handling of constructors and conversion ops. */
5434 {
5438 /* We're doing return_type(x). */
5440 else
5441 /* We're doing x.operator return_type(). */
5443 /* [over.match.funcs] For conversion functions, the function
5444 is considered to be a member of the class of the implicit
5445 object argument for the purpose of defining the type of
5446 the implicit object parameter. */
5448 }
5449 else
5450 {
5452 {
5454 /* For list-initialization we consider explicit constructors
5455 and complain if one is chosen. */
5456 check_converting
5459 }
5462 }
5466 else
5467 /* Delay creating the implicit this parameter until it is needed. */
5471 {
5483 {
5484 /* Figure out where the object arg comes from. If this
5485 function is a non-static member and we didn't get an
5486 implicit object argument, move it out of args. */
5488 {
5490 tree arg;
5497 }
5501 }
5505 fn,
5506 ctype,
5507 explicit_targs,
5508 fn_first_arg,
5509 fn_args,
5510 return_type,
5511 access_path,
5512 conversion_path,
5513 flags,
5514 strict,
5515 complain);
5518 fn,
5519 ctype,
5520 fn_first_arg,
5521 fn_args,
5522 access_path,
5523 conversion_path,
5524 flags,
5525 complain);
5526 }
5527 }
5529 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5530 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5532 static int
5534 {
5536 {
5537 // 5. b @= a
5541 // 6. a[b]
5545 // 1. a.b
5546 // Not overloadable (yet).
5547 // 2. a->b
5548 // Only one argument.
5549 // 3. a->*b
5551 // 7. a << b
5553 // 8. a >> b
5559 }
5560 }
5562 static tree
5565 {
5568 tree fnname;
5586 {
5590 }
5591 else
5598 {
5603 /* Use build_op_new_call and build_op_delete_call instead. */
5607 /* Use build_op_call instead. */
5614 /* These are saved for the sake of warn_logical_operator. */
5624 /* These are saved for the sake of maybe_warn_bool_compare. */
5629 /* =, ->, [], () must be non-static member functions. */
5633 /* FALLTHRU */
5641 }
5647 /* Use build_conditional_expr instead. */
5663 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5666 /* Add namespace-scope operators to the list of functions to
5667 consider. */
5669 {
5675 }
5681 /* Add class-member operators to the candidate set. */
5683 {
5684 tree fns;
5688 {
5691 }
5699 }
5700 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5701 only non-member functions that have type T1 or reference to
5702 cv-qualified-opt T1 for the first argument, if the first argument
5703 has an enumeration type, or T2 or reference to cv-qualified-opt
5704 T2 for the second argument, if the second argument has an
5705 enumeration type. Filter out those that don't match. */
5707 {
5711 {
5721 {
5727 && (same_type_ignoring_top_level_qualifiers_p
5732 }
5734 /* No argument has an appropriate type, so remove this
5735 candidate function from the list. */
5737 {
5740 }
5741 }
5742 }
5748 {
5751 /* For these, the built-in candidates set is empty
5752 [over.match.oper]/3. We don't want non-strict matches
5753 because exact matches are always possible with built-in
5754 operators. The built-in candidate set for COMPONENT_REF
5755 would be empty too, but since there are no such built-in
5756 operators, we accept non-strict matches for them. */
5763 }
5767 {
5769 {
5772 /* Don't try anything fancy if we're not allowed to produce
5773 errors. */
5777 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5778 distinguish between prefix and postfix ++ and
5779 operator++() was used for both, so we allow this with
5780 -fpermissive. */
5781 else
5782 {
5788 }
5795 else
5801 /* The caller will deal with these. */
5811 {
5812 /* If one of the arguments of the operator represents
5813 an invalid use of member function pointer, try to report
5814 a meaningful error ... */
5819 else
5820 {
5821 /* ... Otherwise, report the more generic
5822 "no matching operator found" error */
5825 }
5826 }
5829 }
5830 }
5831 else
5832 {
5835 {
5837 {
5840 }
5842 }
5844 {
5850 else
5856 {
5861 /* This prevents build_new_function_call from discarding this
5862 function during instantiation of the enclosing template. */
5865 /* Specify evaluation order as per P0145R2. */
5868 {
5879 }
5880 }
5881 }
5882 else
5883 {
5884 /* Give any warnings we noticed during overload resolution. */
5886 {
5890 }
5892 /* Check for comparison of different enum types. */
5894 {
5906 {
5910 }
5914 }
5916 /* We need to strip any leading REF_BIND so that bitfields
5917 don't cause errors. This should not remove any important
5918 conversions, because builtins don't apply to class
5919 objects directly. */
5926 {
5930 else
5933 /* We need to call warn_logical_operator before
5934 converting arg2 to a boolean_type, but after
5935 decaying an enumerator to its value. */
5942 }
5944 {
5949 }
5951 }
5952 }
5954 user_defined_result_ready:
5956 /* Free all the conversions we allocated. */
5962 builtin:
5964 {
5979 /* Fall through. */
5992 /* Fall through. */
6025 complain),
6028 /* The caller will deal with these. */
6036 }
6038 }
6040 /* Wrapper for above. */
6042 tree
6046 {
6047 tree ret;
6053 }
6055 /* CALL was returned by some call-building function; extract the actual
6056 CALL_EXPR from any bits that have been tacked on, e.g. by
6057 convert_from_reference. */
6059 tree
6061 {
6072 }
6074 /* Returns true if FN has two parameters, of which the second has type
6075 size_t. */
6077 static bool
6079 {
6091 }
6093 /* True if T, an allocation function, has std::align_val_t as its second
6094 argument. */
6096 bool
6098 {
6104 }
6106 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6107 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6108 std::align_val_t. */
6110 static bool
6112 {
6116 /* A template instance is never a usual deallocation function,
6117 regardless of its signature. */
6133 }
6135 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6136 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6138 bool
6140 {
6141 /* A template instance is never a usual deallocation function,
6142 regardless of its signature. */
6147 /* If a class T has a member deallocation function named operator delete
6148 with exactly one parameter, then that function is a usual
6149 (non-placement) deallocation function. If class T does not declare
6150 such an operator delete but does declare a member deallocation
6151 function named operator delete with exactly two parameters, the second
6152 of which has type std::size_t (18.2), then this function is a usual
6153 deallocation function. */
6165 }
6167 /* Build a call to operator delete. This has to be handled very specially,
6168 because the restrictions on what signatures match are different from all
6169 other call instances. For a normal delete, only a delete taking (void *)
6170 or (void *, size_t) is accepted. For a placement delete, only an exact
6171 match with the placement new is accepted.
6173 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6174 ADDR is the pointer to be deleted.
6175 SIZE is the size of the memory block to be deleted.
6176 GLOBAL_P is true if the delete-expression should not consider
6177 class-specific delete operators.
6178 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6180 If this call to "operator delete" is being generated as part to
6181 deallocate memory allocated via a new-expression (as per [expr.new]
6182 which requires that if the initialization throws an exception then
6183 we call a deallocation function), then ALLOC_FN is the allocation
6184 function. */
6186 tree
6190 {
6204 /* In [class.free]
6206 If the result of the lookup is ambiguous or inaccessible, or if
6207 the lookup selects a placement deallocation function, the
6208 program is ill-formed.
6210 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6211 {
6215 }
6216 else
6222 /* Strip const and volatile from addr. */
6226 {
6227 /* "A declaration of a placement deallocation function matches the
6228 declaration of a placement allocation function if it has the same
6229 number of parameters and, after parameter transformations (8.3.5),
6230 all parameter types except the first are identical."
6232 So we build up the function type we want and ask instantiate_type
6233 to get it for us. */
6244 /* "If the lookup finds the two-parameter form of a usual deallocation
6245 function (3.7.4.2) and that function, considered as a placement
6246 deallocation function, would have been selected as a match for the
6247 allocation function, the program is ill-formed." */
6249 {
6257 /* But if the class has an operator delete (void *), then that is
6258 the usual deallocation function, so we shouldn't complain
6259 about using the operator delete (void *, size_t). */
6263 {
6268 }
6269 /* Before C++14 a two-parameter global deallocation function is
6270 always a placement deallocation function, but warn if
6271 -Wc++14-compat. */
6273 {
6278 }
6281 {
6283 {
6284 /* Only mention C++14 for namespace-scope delete. */
6287 else
6289 "%qD is a usual (non-placement) deallocation "
6291 }
6292 }
6293 else
6295 ok:;
6296 }
6297 }
6298 else
6299 /* "Any non-placement deallocation function matches a non-placement
6300 allocation function. If the lookup finds a single matching
6301 deallocation function, that function will be called; otherwise, no
6302 deallocation function will be called." */
6304 {
6307 {
6309 {
6312 }
6314 /* -- If the type has new-extended alignment, a function with a
6315 parameter of type std::align_val_t is preferred; otherwise a
6316 function without such a parameter is preferred. If exactly one
6317 preferred function is found, that function is selected and the
6318 selection process terminates. If more than one preferred
6319 function is found, all non-preferred functions are eliminated
6320 from further consideration. */
6322 {
6328 {
6332 }
6333 }
6335 /* -- If the deallocation functions have class scope, the one
6336 without a parameter of type std::size_t is selected. */
6341 /* -- If the type is complete and if, for the second alternative
6342 (delete array) only, the operand is a pointer to a class type
6343 with a non-trivial destructor or a (possibly multi-dimensional)
6344 array thereof, the function with a parameter of type std::size_t
6345 is selected.
6347 -- Otherwise, it is unspecified whether a deallocation function
6348 with a parameter of type std::size_t is selected. */
6349 else
6350 {
6354 /* We need a cookie to determine the array size. */
6356 }
6362 }
6363 }
6365 /* If we have a matching function, call it. */
6367 {
6370 /* If the FN is a member function, make sure that it is
6371 accessible. */
6374 complain);
6376 /* Core issue 901: It's ok to new a type with deleted delete. */
6381 {
6382 /* The placement args might not be suitable for overload
6383 resolution at this point, so build the call directly. */
6393 }
6394 else
6395 {
6396 tree ret;
6402 {
6405 }
6409 }
6410 }
6412 /* [expr.new]
6414 If no unambiguous matching deallocation function can be found,
6415 propagating the exception does not cause the object's memory to
6416 be freed. */
6418 {
6422 alloc_fn);
6424 }
6430 }
6432 /* If the current scope isn't allowed to access DECL along
6433 BASETYPE_PATH, give an error. The most derived class in
6434 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6435 the declaration to use in the error diagnostic. */
6437 bool
6440 {
6445 {
6446 /* 7.3.3/18: The additional constructors are accessible if they would be
6447 accessible when used to construct an object of the corresponding base
6448 class. */
6452 }
6455 {
6457 {
6461 {
6467 }
6469 {
6475 }
6476 else
6477 {
6482 }
6483 }
6485 }
6488 }
6490 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6491 bitwise or of LOOKUP_* values. If any errors are warnings are
6492 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6493 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6494 to NULL. */
6496 static tree
6499 {
6505 /* If the source is a packed field, calling the copy constructor will require
6506 binding the field to the reference parameter to the copy constructor, and
6507 we'll end up with an infinite loop. If we can use a bitwise copy, then
6508 do that now. */
6524 }
6526 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6527 EXPR is implicitly converted to type TOTYPE.
6528 FN and ARGNUM are used for diagnostics. */
6530 static void
6532 {
6533 /* Issue warnings about peculiar, but valid, uses of NULL. */
6536 {
6537 source_location loc =
6544 else
6547 }
6549 /* Issue warnings if "false" is converted to a NULL pointer */
6552 {
6555 "converting %<false%> to pointer type for argument %P "
6557 else
6560 }
6561 }
6563 /* We gave a diagnostic during a conversion. If this was in the second
6564 standard conversion sequence of a user-defined conversion sequence, say
6565 which user-defined conversion. */
6567 static void
6569 {
6573 {
6577 }
6578 }
6580 /* Perform the conversions in CONVS on the expression EXPR. FN and
6581 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6582 indicates the `this' argument of a method. INNER is nonzero when
6583 being called to continue a conversion chain. It is negative when a
6584 reference binding will be applied, positive otherwise. If
6585 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6586 conversions will be emitted if appropriate. If C_CAST_P is true,
6587 this conversion is coming from a C-style cast; in that case,
6588 conversions to inaccessible bases are permitted. */
6590 static tree
6594 {
6596 diagnostic_t diag_kind;
6612 {
6616 /* Give a helpful error if this is bad because of excess braces. */
6621 {
6627 }
6629 /* Give a helpful error if this is bad because a conversion to bool
6630 from std::nullptr_t requires direct-initialization. */
6638 {
6640 {
6643 totype);
6649 complain);
6653 complain);
6654 else
6660 }
6662 {
6666 complain);
6668 }
6673 complain);
6676 }
6685 }
6691 {
6693 {
6697 /* When converting from an init list we consider explicit
6698 constructors, but actually trying to call one is an error. */
6701 /* Unless this is for direct-list-initialization. */
6703 /* And in C++98 a default constructor can't be explicit. */
6705 {
6711 {
6717 }
6718 else
6721 }
6723 /* If we're initializing from {}, it's value-initialization. */
6727 {
6732 {
6735 }
6737 }
6741 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6742 any more UDCs. */
6744 complain);
6746 /* If this is a constructor or a function returning an aggr type,
6747 we need to build up a TARGET_EXPR. */
6749 {
6752 /* Remember that this was list-initialization. */
6755 }
6758 }
6761 {
6767 else
6769 }
6776 /* We leave bad_p off ck_ambig because overload resolution considers
6777 it valid, it just fails when we try to perform it. So we need to
6778 check complain here, too. */
6780 {
6781 /* Call build_user_type_conversion again for the error. */
6783 complain);
6787 }
6791 {
6792 /* Conversion to std::initializer_list<T>. */
6800 /* Convert all the elements. */
6802 {
6813 }
6814 /* Build up the array. */
6815 elttype = cp_build_qualified_type
6819 /* Take the address explicitly rather than via decay_conversion
6820 to avoid the error about taking the address of a temporary. */
6826 /* Build up the initializer_list object. */
6834 }
6838 {
6847 }
6850 complain);
6857 };
6861 c_cast_p,
6862 complain);
6867 {
6871 {
6873 {
6878 }
6880 }
6885 /* Don't introduce copies when passing arguments along to the inherited
6886 constructor. */
6888 && flag_new_inheriting_ctors
6892 /* Fall through. */
6895 {
6896 /* We are going to bind a reference directly to a base-class
6897 subobject of EXPR. */
6898 /* Build an expression for `*((base*) &expr)'. */
6902 }
6904 /* Copy-initialization where the cv-unqualified version of the source
6905 type is the same class as, or a derived class of, the class of the
6906 destination [is treated as direct-initialization]. [dcl.init] */
6909 /* This conversion is being done in the context of a user-defined
6910 conversion (i.e. the second step of copy-initialization), so
6911 don't allow any more. */
6913 else
6916 /* standard_conversion got LOOKUP_PREFER_RVALUE. */
6920 /* Copy-list-initialization doesn't actually involve a copy. */
6924 {
6929 }
6934 {
6938 {
6951 else
6958 }
6960 /* If necessary, create a temporary.
6962 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6963 that need temporaries, even when their types are reference
6964 compatible with the type of reference being bound, so the
6965 upcoming call to cp_build_addr_expr doesn't fail. */
6969 {
6970 /* Otherwise, a temporary of type "cv1 T1" is created and
6971 initialized from the initializer expression using the rules
6972 for a non-reference copy-initialization (8.5). */
6981 {
6982 /* If the reference is volatile or non-const, we
6983 cannot create a temporary. */
6990 else
6994 }
6995 /* If the source is a packed field, and we must use a copy
6996 constructor, then building the target expr will require
6997 binding the field to the reference parameter to the
6998 copy constructor, and we'll end up with an infinite
6999 loop. If we can use a bitwise copy, then we'll be
7000 OK. */
7004 {
7008 }
7010 {
7013 }
7015 }
7017 /* Take the address of the thing to which we will bind the
7018 reference. */
7023 /* Convert it to a pointer to the type referred to by the
7024 reference. This will adjust the pointer if a derived to
7025 base conversion is being performed. */
7028 /* Convert the pointer to the desired reference type. */
7030 }
7036 /* ??? Should the address of a transaction-safe pointer point to the TM
7037 clone, and this conversion look up the primary function? */
7041 /* Warn about deprecated conversion if appropriate. */
7057 }
7065 else
7069 }
7071 /* ARG is being passed to a varargs function. Perform any conversions
7072 required. Return the converted value. */
7074 tree
7076 {
7077 tree arg_type;
7080 /* [expr.call]
7082 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7083 standard conversions are performed. */
7086 /* [expr.call]
7088 If the argument has integral or enumeration type that is subject
7089 to the integral promotions (_conv.prom_), or a floating point
7090 type that is subject to the floating point promotion
7091 (_conv.fpprom_), the value of the argument is converted to the
7092 promoted type before the call. */
7097 {
7101 "implicit conversion from %qH to %qI when passing "
7105 }
7109 {
7111 {
7113 complain);
7123 }
7124 else
7126 }
7132 /* In a template (or ill-formed code), we can have an incomplete type
7133 even after require_complete_type_sfinae, in which case we don't know
7134 whether it has trivial copy or not. */
7136 {
7137 /* Build up a real lvalue-to-rvalue conversion in case the
7138 copy constructor is trivial but not callable. */
7142 /* [expr.call] 5.2.2/7:
7143 Passing a potentially-evaluated argument of class type (Clause 9)
7144 with a non-trivial copy constructor or a non-trivial destructor
7145 with no corresponding parameter is conditionally-supported, with
7146 implementation-defined semantics.
7148 We support it as pass-by-invisible-reference, just like a normal
7149 value parameter.
7151 If the call appears in the context of a sizeof expression,
7152 it is not potentially-evaluated. */
7156 {
7159 "passing objects of non-trivially-copyable "
7161 arg_type);
7163 }
7164 }
7167 }
7169 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7171 tree
7173 {
7175 {
7179 }
7189 {
7192 }
7196 {
7197 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7198 it as pass by invisible reference. */
7200 "receiving objects of non-trivially-copyable type %q#T "
7206 }
7210 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7211 know how to handle it. */
7214 }
7216 /* TYPE has been given to va_arg. Apply the default conversions which
7217 would have happened when passed via ellipsis. Return the promoted
7218 type, or the passed type if there is no change. */
7220 tree
7222 {
7223 tree promote;
7225 /* Perform the array-to-pointer and function-to-pointer
7226 conversions. */
7234 }
7236 /* ARG is a default argument expression being passed to a parameter of
7237 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7238 zero-based argument number. Do any required conversions. Return
7239 the converted value. */
7242 void
7246 void
7250 tree
7252 tsubst_flags_t complain)
7253 {
7255 tree t;
7257 /* See through clones. */
7259 /* And inheriting ctors. */
7263 /* Detect recursion. */
7266 {
7270 }
7272 /* If the ARG is an unparsed default argument expression, the
7273 conversion cannot be performed. */
7275 {
7280 }
7287 /* Due to:
7289 [dcl.fct.default]
7291 The names in the expression are bound, and the semantic
7292 constraints are checked, at the point where the default
7293 expressions appears.
7295 we must not perform access checks here. */
7297 /* We must make a copy of ARG, in case subsequent processing
7298 alters any part of it. */
7302 complain);
7309 }
7311 /* Returns the type which will really be used for passing an argument of
7312 type TYPE. */
7314 tree
7316 {
7317 /* Pass classes with copy ctors by invisible reference. */
7319 {
7321 /* There are no other pointers to this temporary. */
7323 }
7331 }
7333 /* Actually perform the appropriate conversion. */
7335 tree
7337 {
7338 tree bitfield_type;
7340 /* If VAL is a bitfield, then -- since it has already been converted
7341 to TYPE -- it cannot have a precision greater than TYPE.
7343 If it has a smaller precision, we must widen it here. For
7344 example, passing "int f:3;" to a function expecting an "int" will
7345 not result in any conversion before this point.
7347 If the precision is the same we must not risk widening. For
7348 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7349 often have type "int", even though the C++ type for the field is
7350 "long long". If the value is being passed to a function
7351 expecting an "int", then no conversions will be required. But,
7352 if we call convert_bitfield_to_declared_type, the bitfield will
7353 be converted to "long long". */
7360 ;
7361 /* Pass classes with copy ctors by invisible reference. */
7370 {
7372 {
7380 "argument of function call might be a candidate "
7382 }
7384 }
7386 }
7388 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7389 which just decay_conversion or no conversions at all should be done.
7390 This is true for some builtins which don't act like normal functions.
7391 Return 2 if no conversions at all should be done, 1 if just
7392 decay_conversion. Return 3 for special treatment of the 3rd argument
7393 for __builtin_*_overflow_p. */
7395 int
7397 {
7403 {
7418 }
7421 }
7423 /* Returns the decl of the dispatcher function if FN is a function version. */
7425 tree
7427 {
7437 {
7441 }
7446 }
7448 /* fn is a function version dispatcher that is marked used. Mark all the
7449 semantically identical function versions it will dispatch as used. */
7451 void
7453 {
7470 /* All semantically identical versions are chained. Traverse and mark each
7471 one of them as used. */
7474 {
7477 }
7478 }
7480 /* Build a call to "the copy constructor" for the type of A, even if it
7481 wouldn't be selected by normal overload resolution. Used for
7482 diagnostics. */
7484 static tree
7486 {
7497 }
7499 /* Return true iff T refers to a base field. */
7501 static bool
7503 {
7512 }
7514 /* We can't elide a copy from a function returning by value to a base
7515 subobject, as the callee might clobber tail padding. Return true iff this
7516 could be that case. */
7518 static bool
7520 {
7521 /* Copy elision only happens with a TARGET_EXPR. */
7525 /* It's safe to elide the copy for a class with no tail padding. */
7528 /* It's safe to elide the copy if we aren't initializing a base object. */
7532 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7537 }
7539 /* Subroutine of the various build_*_call functions. Overload resolution
7540 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7541 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7542 bitmask of various LOOKUP_* flags which apply to the call itself. */
7544 static tree
7546 {
7554 tree val;
7563 /* In a template, there is no need to perform all of the work that
7564 is normally done. We are only interested in the type of the call
7565 expression, i.e., the return type of the function. Any semantic
7566 errors will be deferred until the template is instantiated. */
7568 {
7570 tree return_type;
7581 else
7582 {
7585 tree arg;
7593 }
7603 }
7605 /* Give any warnings we noticed during overload resolution. */
7607 {
7611 }
7613 /* OK, we're actually calling this inherited constructor; set its deletedness
7614 appropriately. We can get away with doing this here because calling is
7615 the only way to refer to a constructor. */
7619 /* Make =delete work with SFINAE. */
7624 {
7625 tree access_fn;
7626 /* If FN is a template function, two cases must be considered.
7627 For example:
7629 struct A {
7630 protected:
7631 template <class T> void f();
7632 };
7633 template <class T> struct B {
7634 protected:
7635 void g();
7636 };
7637 struct C : A, B<int> {
7638 using A::f; // #1
7639 using B<int>::g; // #2
7640 };
7642 In case #1 where `A::f' is a member template, DECL_ACCESS is
7643 recorded in the primary template but not in its specialization.
7644 We check access of FN using its primary template.
7646 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7647 because it is a member of class template B, DECL_ACCESS is
7648 recorded in the specialization `B<int>::g'. We cannot use its
7649 primary template because `B<T>::g' and `B<int>::g' may have
7650 different access. */
7654 else
7659 }
7661 /* If we're checking for implicit delete, don't bother with argument
7662 conversions. */
7664 {
7666 {
7670 }
7674 /* Reject bad conversions now. */
7676 /* else continue to get conversion error. */
7677 }
7679 /* N3276 magic doesn't apply to nested calls. */
7683 /* Find maximum size of vector to hold converted arguments. */
7690 /* The implicit parameters to a constructor are not considered by overload
7691 resolution, and must be of the proper type. */
7693 {
7694 tree object_arg;
7696 {
7699 }
7700 else
7701 {
7704 }
7707 /* We should never try to call the abstract constructor. */
7711 {
7715 }
7718 {
7719 /* The implicit move specified in 15.8.3/3 fails "...if the type of
7720 the first parameter of the selected constructor is not an rvalue
7721 reference to the object’s type (possibly cv-qualified)...." */
7728 }
7729 }
7730 /* Bypass access control for 'this' parameter. */
7732 {
7735 ? first_arg
7738 tree converted_arg;
7739 tree base_binfo;
7742 {
7744 {
7749 }
7750 else
7752 }
7754 /* See if the function member or the whole class type is declared
7755 final and the call can be devirtualized. */
7760 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7761 X is called for an object that is not of type X, or of a type
7762 derived from X, the behavior is undefined.
7764 So we can assume that anything passed as 'this' is non-null, and
7765 optimize accordingly. */
7767 /* Convert to the base in which the function was declared. */
7770 arg,
7773 /* Check that the base class is accessible. */
7776 {
7781 else
7783 }
7784 /* If fn was found by a using declaration, the conversion path
7785 will be to the derived class, not the base declaring fn. We
7786 must convert from derived to base. */
7797 else
7801 }
7806 {
7813 /* If the argument is NULL and used to (implicitly) instantiate a
7814 template function (and bind one of the template arguments to
7815 the type of 'long int'), we don't want to warn about passing NULL
7816 to non-pointer argument.
7817 For example, if we have this template function:
7819 template<typename T> void func(T x) {}
7821 we want to warn (when -Wconversion is enabled) in this case:
7823 void foo() {
7824 func<int>(NULL);
7825 }
7827 but not in this case:
7829 void foo() {
7830 func(NULL);
7831 }
7832 */
7839 /* Warn about initializer_list deduction that isn't currently in the
7840 working draft. */
7842 && flag_deduce_init_list
7846 {
7859 {
7867 }
7868 }
7870 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7871 knows not to allow any more UDCs. This needs to happen after we
7872 process cand->warnings. */
7881 arg_complain);
7886 else
7888 }
7890 /* Default arguments */
7892 {
7898 complain);
7902 }
7904 /* Ellipsis */
7907 {
7910 {
7911 /* Do no conversions for certain magic varargs. */
7915 }
7917 /* For other magic varargs only do decay_conversion. */
7922 {
7923 /* Avoid infinite recursion trying to call A(...). */
7925 /* Try to call the actual copy constructor for a good error. */
7928 }
7929 else
7934 }
7939 /* Avoid to do argument-transformation, if warnings for format, and for
7940 nonnull are disabled. Just in case that at least one of them is active
7941 the check_function_arguments function might warn about something. */
7945 || warn_format
7946 || warn_suggest_attribute_format
7948 {
7956 }
7959 {
7960 /* Check for passing ellipsis arguments to an inherited constructor. We
7961 could handle this by open-coding the inherited constructor rather than
7962 defining it, but let's not bother now. */
7966 {
7968 {
7972 }
7974 }
7976 /* A base constructor inheriting from a virtual base doesn't get the
7977 inherited arguments, just this and __vtt. */
7980 }
7982 /* Avoid actually calling copy constructors and copy assignment operators,
7983 if possible. */
7990 /* It's unsafe to elide the constructor when handling
7991 a noexcept-expression, it may evaluate to the wrong
7992 value (c++/53025). */
7994 {
7995 tree targ;
7997 tree fa;
8000 /* Pull out the real argument, disregarding const-correctness. */
8002 /* Strip the reference binding for the constructor parameter. */
8006 /* But don't strip any other reference bindings; binding a temporary to a
8007 reference prevents copy elision. */
8013 {
8018 }
8019 else
8024 else
8027 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8028 subobject. */
8031 /* It's from binding the ref parm to a packed field. */
8034 /* See unsafe_copy_elision_p. */
8037 /* [class.copy]: the copy constructor is implicitly defined even if
8038 the implementation elided its use. */
8040 {
8044 }
8046 /* If we're creating a temp and we already have one, don't create a
8047 new one. If we're not creating a temp but we get one, use
8048 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8049 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8050 temp or an INIT_EXPR otherwise. */
8053 {
8058 }
8061 {
8063 RO_NULL,
8064 complain));
8068 }
8069 }
8073 {
8074 tree to = cp_stabilize_reference
8081 {
8082 /* Avoid copying empty classes. */
8085 }
8087 {
8090 /* Handle NSDMI that refer to the object being initialized. */
8092 }
8093 else
8094 {
8095 /* We must only copy the non-tail padding parts. */
8103 build_index_type
8112 }
8115 }
8118 {
8122 {
8125 else
8127 }
8128 }
8130 /* For calls to a multi-versioned function, overload resolution
8131 returns the function with the highest target priority, that is,
8132 the version that will checked for dispatching first. If this
8133 version is inlinable, a direct call to this version can be made
8134 otherwise the call should go through the dispatcher. */
8139 {
8145 }
8152 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8153 virtual functions can't be constexpr. */
8155 {
8156 tree t;
8163 complain);
8169 }
8170 else
8171 {
8175 }
8181 {
8183 /* build_new_op_1 will clear this when appropriate. */
8185 }
8187 {
8191 }
8193 }
8195 /* Return the DECL of the first non-public data member of class TYPE
8196 or null if none can be found. */
8198 static tree
8200 {
8205 {
8212 }
8218 {
8223 }
8226 }
8228 /* Return true if all copy and move assignment operator overloads for
8229 class TYPE are trivial and at least one of them is not deleted and,
8230 when ACCESS is set, accessible. Return false otherwise. Set
8231 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8232 copy or move assignment. */
8234 static bool
8236 {
8242 /* Iterate over overloads of the assignment operator, checking
8243 accessible copy assignments for triviality. */
8246 {
8249 /* Skip operators that aren't copy assignments. */
8256 /* Skip template assignment operators and deleted functions. */
8266 /* Break early when both properties have been determined. */
8269 }
8271 /* Return true if they're all trivial and one of the expressions
8272 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8277 }
8279 /* Return true if all copy and move ctor overloads for class TYPE are
8280 trivial and at least one of them is not deleted and, when ACCESS is
8281 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8282 to true when the TYPE has a (not necessarily trivial) default and copy
8283 (or move) ctor, respectively. */
8285 static bool
8287 {
8293 {
8296 /* Skip template constructors. */
8302 /* Skip ctors other than default, copy, and move. */
8318 /* Break early when both properties have been determined. */
8321 }
8324 }
8326 /* Issue a warning on a call to the built-in function FNDECL if it is
8327 a raw memory write whose destination is not an object of (something
8328 like) trivial or standard layout type with a non-deleted assignment
8329 and copy ctor. Detects const correctness violations, corrupting
8330 references, virtual table pointers, and bypassing non-trivial
8331 assignments. */
8333 static void
8335 {
8336 /* Except for bcopy where it's second, the destination pointer is
8337 the first argument for all functions handled here. Compute
8338 the index of the destination and source arguments. */
8346 /* Remove the outermost (usually implicit) conversion to the void*
8347 argument type. */
8353 /* Determine the type of the pointed-to object and whether it's
8354 a complete class type. */
8360 /* Check to see if the raw memory call is made by a ctor or dtor
8361 with this as the destination argument for the destination type.
8362 If so, be more permissive. */
8367 {
8373 /* A ctor and dtor for a class with no bases and no virtual functions
8374 can do whatever they want. Bail early with no further checking. */
8377 }
8379 /* True if the class is trivial. */
8382 /* Set to true if DESTYPE has an accessible copy assignment. */
8384 /* True if all of the class' overloaded copy assignment operators
8385 are all trivial (and not deleted) and at least one of them is
8386 accessible. */
8389 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8390 respectively. */
8393 /* True if all of the class' overloaded copy constructors are all
8394 trivial (and not deleted) and at least one of them is accessible. */
8397 /* Set FLD to the first private/protected member of the class. */
8400 /* The warning format string. */
8402 /* A suggested alternative to offer instead of the raw memory call.
8403 Empty string when none can be come up with. */
8408 {
8411 {
8412 /* Diagnose setting non-copy-assignable or non-trivial types,
8413 or types with a private member, to (potentially) non-zero
8414 bytes. Since the value of the bytes being written is unknown,
8415 suggest using assignment instead (if one exists). Also warn
8416 for writes into objects for which zero-initialization doesn't
8417 mean all bits clear (pointer-to-member data, where null is all
8418 bits set). Since the value being written is (most likely)
8419 non-zero, simply suggest assignment (but not copy assignment). */
8427 {
8430 "%qD writing to an object of type %#qT with "
8433 }
8439 }
8440 /* Fall through. */
8443 /* Similarly to the above, diagnose clearing non-trivial or non-
8444 standard layout objects, or objects of types with no assignmenmt.
8445 Since the value being written is known to be zero, suggest either
8446 copy assignment, copy ctor, or default ctor as an alternative,
8447 depending on what's available. */
8470 /* Determine the type of the source object. */
8474 /* Since it's impossible to determine wheter the byte copy is
8475 being used in place of assignment to an existing object or
8476 as a substitute for initialization, assume it's the former.
8477 Determine the best alternative to use instead depending on
8478 what's not deleted. */
8499 srctype))
8500 {
8501 /* Warn when copying into a non-trivial object from an object
8502 of a different type other than void or char. */
8504 "%qD copying an object of non-trivial type "
8507 }
8512 srctype))
8513 {
8516 "%qD copying an object of type %#qT with "
8517 "%qs member %qD from an array of %#qT; use "
8520 }
8522 {
8523 /* Finally, warn on partial copies. */
8524 unsigned HOST_WIDE_INT typesize
8531 "a non-trivial type %#qT leaves %wu "
8534 "a non-trivial type %#qT leaves %wu "
8537 }
8554 {
8555 /* Finally, warn on reallocation into insufficient space. */
8557 "%qD moving an object of non-trivial type "
8561 }
8566 }
8572 {
8576 else
8579 }
8583 }
8585 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8586 This function performs no overload resolution, conversion, or other
8587 high-level operations. */
8589 tree
8591 tsubst_flags_t complain)
8592 {
8593 tree fndecl;
8595 /* Remember roughly where this call is. */
8602 /* Check that arguments to builtin functions match the expectations. */
8606 {
8609 /* We need to take care that values to BUILT_IN_NORMAL
8610 are reduced. */
8618 /* Warn if the built-in writes to an object of a non-trivial type. */
8621 }
8623 /* If it is a built-in array notation function, then the return type of
8624 the function is the element type of the array passed in as array
8625 notation (i.e. the first parameter of the function). */
8627 {
8636 {
8638 {
8641 }
8642 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
8643 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
8644 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
8645 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
8646 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
8647 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
8648 The pre-defined return-type is the correct one. */
8652 }
8653 }
8658 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8659 function call is either the operand of a decltype-specifier or the
8660 right operand of a comma operator that is the operand of a
8661 decltype-specifier, a temporary object is not introduced for the
8662 prvalue. The type of the prvalue may be incomplete. */
8664 {
8670 {
8673 }
8674 }
8676 }
8678 /* Returns the value to use for the in-charge parameter when making a
8679 call to a function with the indicated NAME.
8681 FIXME:Can't we find a neater way to do this mapping? */
8683 tree
8685 {
8687 {
8691 }
8692 else
8693 {
8699 }
8702 }
8704 /* We've built up a constructor call RET. Complain if it delegates to the
8705 constructor we're currently compiling. */
8707 static void
8709 {
8715 }
8717 /* Build a call to a constructor, destructor, or an assignment
8718 operator for INSTANCE, an expression with class type. NAME
8719 indicates the special member function to call; *ARGS are the
8720 arguments. ARGS may be NULL. This may change ARGS. BINFO
8721 indicates the base of INSTANCE that is to be passed as the `this'
8722 parameter to the member function called.
8724 FLAGS are the LOOKUP_* flags to use when processing the call.
8726 If NAME indicates a complete object constructor, INSTANCE may be
8727 NULL_TREE. In this case, the caller will call build_cplus_new to
8728 store the newly constructed object into a VAR_DECL. */
8730 tree
8733 {
8734 tree fns;
8735 /* The type of the subobject to be constructed or destroyed. */
8736 tree class_type;
8738 tree ret;
8743 {
8744 /* Resolve the name. */
8749 }
8755 /* Handle the special case where INSTANCE is NULL_TREE. */
8758 else
8759 {
8763 /* Convert to the base class, if necessary. */
8766 {
8768 /* For constructors and destructors, either the base is
8769 non-virtual, or it is virtual but we are doing the
8770 conversion from a constructor or destructor for the
8771 complete object. In either case, we can convert
8772 statically. */
8774 else
8775 /* However, for assignment operators, we must convert
8776 dynamically if the base is virtual. */
8779 }
8780 }
8784 /* In C++17, "If the initializer expression is a prvalue and the
8785 cv-unqualified version of the source type is the same class as the class
8786 of the destination, the initializer expression is used to initialize the
8787 destination object." Handle that here to avoid doing overload
8788 resolution. */
8792 {
8795 /* FIXME P0135 doesn't say how to handle direct initialization from a
8796 type with a suitable conversion operator. Let's handle it like
8797 copy-initialization, but allowing explict conversions. */
8800 /* If we're using this to initialize a non-temporary object, don't
8801 require the destructor to be accessible. */
8805 sub_complain,
8806 flags);
8809 && (same_type_ignoring_top_level_qualifiers_p
8811 {
8817 /* Avoid change of behavior on Wunused-var-2.C. */
8820 }
8821 }
8825 /* When making a call to a constructor or destructor for a subobject
8826 that uses virtual base classes, pass down a pointer to a VTT for
8827 the subobject. */
8831 {
8832 tree vtt;
8833 tree sub_vtt;
8835 /* If the current function is a complete object constructor
8836 or destructor, then we fetch the VTT directly.
8837 Otherwise, we look it up using the VTT we were given. */
8845 else
8849 {
8852 }
8855 }
8860 complain);
8871 }
8873 /* Return the NAME, as a C string. The NAME indicates a function that
8874 is a member of TYPE. *FREE_P is set to true if the caller must
8875 free the memory returned.
8877 Rather than go through all of this, we should simply set the names
8878 of constructors and destructors appropriately, and dispense with
8879 ctor_identifier, dtor_identifier, etc. */
8883 {
8886 /* Assume that we will not allocate memory. */
8888 /* Constructors and destructors are special. */
8890 {
8891 pretty_name
8893 /* For a destructor, add the '~'. */
8895 {
8897 /* Remember that we need to free the memory allocated. */
8899 }
8900 }
8902 {
8905 TFF_PLAIN_IDENTIFIER),
8906 NULL);
8907 /* Remember that we need to free the memory allocated. */
8909 }
8910 else
8914 }
8916 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8917 be set, upon return, to the function called. ARGS may be NULL.
8918 This may change ARGS. */
8920 static tree
8924 {
8929 tree optype;
8931 tree name;
8934 tree call;
8935 tree fn;
8938 tree orig_instance;
8939 tree orig_fns;
8945 /* We don't know what function we're going to call, yet. */
8954 {
8958 }
8963 /* Dismantle the baselink to collect all the information we need. */
8971 {
8975 }
8986 {
8991 }
8994 /* Under DR 147 A::A() is an invalid constructor call,
8995 not a functional cast. */
8997 {
9008 complain);
9010 }
9012 /* Process the argument list. */
9014 {
9018 }
9020 /* Consider the object argument to be used even if we end up selecting a
9021 static member function. */
9025 /* Figure out whether to skip the first argument for the error
9026 message we will display to users if an error occurs. We don't
9027 want to display any compiler-generated arguments. The "this"
9028 pointer hasn't been added yet. However, we must remove the VTT
9029 pointer if this is a call to a base-class constructor or
9030 destructor. */
9033 {
9034 /* Callers should explicitly indicate whether they want to ctor
9035 the complete object or just the part without virtual bases. */
9038 /* Remove the VTT pointer, if present. */
9043 /* It's OK to call destructors and constructors on cv-qualified
9044 objects. Therefore, convert the INSTANCE to the unqualified
9045 type, if necessary. */
9047 {
9051 }
9052 }
9053 else
9056 /* For the overload resolution we need to find the actual `this`
9057 that would be captured if the call turns out to be to a
9058 non-static member function. Do not actually capture it at this
9059 point. */
9061 /* Constructors don't use the enclosing 'this'. */
9063 else
9066 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9069 /* The number of arguments artificial parms in ARGS; we subtract one because
9070 there's no 'this' in ARGS. */
9073 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9074 initializer, not T({ }). */
9078 {
9085 /* If the initializer list has no elements and T is a class type with
9086 a default constructor, the object is value-initialized. Handle
9087 this here so we don't need to handle it wherever we use
9088 build_special_member_call. */
9091 /* For a user-provided default constructor, use the normal
9092 mechanisms so that protected access works. */
9097 /* If BASETYPE is an aggregate, we need to do aggregate
9098 initialization. */
9100 {
9103 }
9106 {
9112 }
9114 /* Otherwise go ahead with overload resolution. */
9119 }
9120 else
9129 {
9131 {
9138 else
9139 {
9144 {
9147 }
9155 }
9157 }
9159 }
9160 else
9161 {
9164 {
9167 tree arglist;
9170 {
9178 else
9184 }
9186 }
9187 else
9188 {
9196 {
9197 /* This is not an error, it is runtime undefined
9198 behavior. */
9207 fn);
9208 }
9213 {
9218 {
9219 /* We captured 'this' in the current lambda now that
9220 we know we really need it. */
9222 }
9224 /* We can't tell until instantiation time whether we can use
9226 else
9227 {
9230 fn);
9232 }
9233 }
9236 {
9237 /* Optimize away vtable lookup if we know that this
9238 function can't be overridden. We need to check if
9239 the context and the type where we found fn are the same,
9240 actually FN might be defined in a different class
9241 type because of a using-declaration. In this case, we
9242 do not want to perform a non-virtual call. */
9244 && same_type_ignoring_top_level_qualifiers_p
9250 /* Now we know what function is being called. */
9253 /* Build the actual CALL_EXPR. */
9255 /* In an expression of the form `a->f()' where `f' turns
9256 out to be a static member function, `a' is
9257 none-the-less evaluated. */
9266 /* An explicit call of the form "x->~X()" has type
9267 "void". However, on platforms where destructors
9268 return "this" (i.e., those where
9269 targetm.cxx.cdtor_returns_this is true), such calls
9270 will appear to have a return value of pointer type
9271 to the low-level call machinery. We do not want to
9272 change the low-level machinery, since we want to be
9273 able to optimize "delete f()" on such platforms as
9274 "operator delete(~X(f()))" (rather than generating
9275 "t = f(), ~X(t), operator delete (t)"). */
9277 }
9278 }
9279 }
9282 {
9288 {
9291 }
9294 call = (build_min_non_dep_call_vec
9298 orig_args));
9303 }
9305 /* Free all the conversions we allocated. */
9312 }
9314 /* Wrapper for above. */
9316 tree
9320 {
9321 tree ret;
9327 }
9329 /* Returns true iff standard conversion sequence ICS1 is a proper
9330 subsequence of ICS2. */
9332 static bool
9334 {
9335 /* We can assume that a conversion of the same code
9336 between the same types indicates a subsequence since we only get
9337 here if the types we are converting from are the same. */
9344 {
9354 /* At this point, ICS1 cannot be a proper subsequence of
9355 ICS2. We can get a USER_CONV when we are comparing the
9356 second standard conversion sequence of two user conversion
9357 sequences. */
9372 }
9373 }
9375 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9376 be any _TYPE nodes. */
9378 bool
9380 {
9384 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9385 considers every class derived from itself. */
9388 }
9390 /* We build the ICS for an implicit object parameter as a pointer
9391 conversion sequence. However, such a sequence should be compared
9392 as if it were a reference conversion sequence. If ICS is the
9393 implicit conversion sequence for an implicit object parameter,
9394 modify it accordingly. */
9396 static void
9398 {
9400 {
9401 /* [over.match.funcs]
9403 For non-static member functions, the type of the
9404 implicit object parameter is "reference to cv X"
9405 where X is the class of which the function is a
9406 member and cv is the cv-qualification on the member
9407 function declaration. */
9409 tree reference_type;
9411 /* The `this' parameter is a pointer to a class type. Make the
9412 implicit conversion talk about a reference to that same class
9413 type. */
9426 }
9427 }
9429 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9430 and return the initial reference binding conversion. Otherwise,
9431 leave *ICS unchanged and return NULL. */
9435 {
9437 {
9442 }
9445 }
9447 /* Compare two implicit conversion sequences according to the rules set out in
9448 [over.ics.rank]. Return values:
9450 1: ics1 is better than ics2
9451 -1: ics2 is better than ics1
9452 0: ics1 and ics2 are indistinguishable */
9454 static int
9456 {
9457 tree from_type1;
9458 tree from_type2;
9459 tree to_type1;
9460 tree to_type2;
9467 /* REF_BINDING is nonzero if the result of the conversion sequence
9468 is a reference type. In that case REF_CONV is the reference
9469 binding conversion. */
9473 /* Compare badness before stripping the reference conversion. */
9479 /* Handle implicit object parameters. */
9483 /* Handle reference parameters. */
9487 /* List-initialization sequence L1 is a better conversion sequence than
9488 list-initialization sequence L2 if L1 converts to
9489 std::initializer_list<X> for some X and L2 does not. */
9495 /* [over.ics.rank]
9497 When comparing the basic forms of implicit conversion sequences (as
9498 defined in _over.best.ics_)
9500 --a standard conversion sequence (_over.ics.scs_) is a better
9501 conversion sequence than a user-defined conversion sequence
9502 or an ellipsis conversion sequence, and
9504 --a user-defined conversion sequence (_over.ics.user_) is a
9505 better conversion sequence than an ellipsis conversion sequence
9506 (_over.ics.ellipsis_). */
9507 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9508 mismatch. If both ICS are bad, we try to make a decision based on
9509 what would have happened if they'd been good. This is not an
9510 extension, we'll still give an error when we build up the call; this
9511 just helps us give a more helpful error message. */
9521 /* Both conversions are ellipsis conversions. */
9524 /* User-defined conversion sequence U1 is a better conversion sequence
9525 than another user-defined conversion sequence U2 if they contain the
9526 same user-defined conversion operator or constructor and if the sec-
9527 ond standard conversion sequence of U1 is better than the second
9528 standard conversion sequence of U2. */
9530 /* Handle list-conversion with the same code even though it isn't always
9531 ranked as a user-defined conversion and it doesn't have a second
9532 standard conversion sequence; it will still have the desired effect.
9533 Specifically, we need to do the reference binding comparison at the
9534 end of this function. */
9537 {
9553 {
9556 }
9557 else
9558 {
9559 /* For ambiguous or aggregate conversions, use the target type as
9560 a proxy for the conversion function. */
9563 }
9565 /* We can just fall through here, after setting up
9566 FROM_TYPE1 and FROM_TYPE2. */
9569 }
9570 else
9571 {
9575 /* We're dealing with two standard conversion sequences.
9577 [over.ics.rank]
9579 Standard conversion sequence S1 is a better conversion
9580 sequence than standard conversion sequence S2 if
9582 --S1 is a proper subsequence of S2 (comparing the conversion
9583 sequences in the canonical form defined by _over.ics.scs_,
9584 excluding any Lvalue Transformation; the identity
9585 conversion sequence is considered to be a subsequence of
9586 any non-identity conversion sequence */
9597 }
9599 /* One sequence can only be a subsequence of the other if they start with
9600 the same type. They can start with different types when comparing the
9601 second standard conversion sequence in two user-defined conversion
9602 sequences. */
9604 {
9609 }
9611 /* [over.ics.rank]
9613 Or, if not that,
9615 --the rank of S1 is better than the rank of S2 (by the rules
9616 defined below):
9618 Standard conversion sequences are ordered by their ranks: an Exact
9619 Match is a better conversion than a Promotion, which is a better
9620 conversion than a Conversion.
9622 Two conversion sequences with the same rank are indistinguishable
9623 unless one of the following rules applies:
9625 --A conversion that does not a convert a pointer, pointer to member,
9626 or std::nullptr_t to bool is better than one that does.
9628 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9629 so that we do not have to check it explicitly. */
9638 /* A conversion from scalar arithmetic type to complex is worse than a
9639 conversion between scalar arithmetic types. */
9646 {
9649 else
9651 }
9657 {
9662 }
9663 /* The rules for pointers to members A::* are just like the rules
9664 for pointers A*, except opposite: if B is derived from A then
9665 A::* converts to B::*, not vice versa. For that reason, we
9666 switch the from_ and to_ variables here. */
9673 {
9678 }
9683 {
9684 /* This was one of the pointer or pointer-like conversions.
9686 [over.ics.rank]
9688 --If class B is derived directly or indirectly from class A,
9689 conversion of B* to A* is better than conversion of B* to
9690 void*, and conversion of A* to void* is better than
9691 conversion of B* to void*. */
9694 {
9696 deref_from_type2))
9699 deref_from_type1))
9701 }
9704 {
9706 {
9708 {
9710 deref_to_type1))
9712 }
9713 /* We know that DEREF_TO_TYPE1 is `void' here. */
9715 deref_to_type2))
9717 }
9718 }
9721 {
9722 /* [over.ics.rank]
9724 --If class B is derived directly or indirectly from class A
9725 and class C is derived directly or indirectly from B,
9727 --conversion of C* to B* is better than conversion of C* to
9728 A*,
9730 --conversion of B* to A* is better than conversion of C* to
9731 A* */
9733 {
9735 deref_to_type2))
9738 deref_to_type1))
9740 }
9742 {
9744 deref_from_type1))
9747 deref_from_type2))
9749 }
9750 }
9751 }
9754 {
9757 /* [over.ics.rank]
9759 --binding of an expression of type C to a reference of type
9760 B& is better than binding an expression of type C to a
9761 reference of type A&
9763 --conversion of C to B is better than conversion of C to A, */
9766 {
9771 }
9772 }
9775 {
9778 /* [over.ics.rank]
9780 --binding of an expression of type B to a reference of type
9781 A& is better than binding an expression of type C to a
9782 reference of type A&,
9784 --conversion of B to A is better than conversion of C to A */
9787 {
9792 }
9793 }
9795 /* [over.ics.rank]
9797 --S1 and S2 differ only in their qualification conversion and yield
9798 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9799 qualification signature of type T1 is a proper subset of the cv-
9800 qualification signature of type T2 */
9804 {
9808 }
9810 /* [over.ics.rank]
9812 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9813 to an implicit object parameter of a non-static member function
9814 declared without a ref-qualifier, and either S1 binds an lvalue
9815 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9816 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9817 draft standard, 13.3.3.2)
9819 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9820 types to which the references refer are the same type except for
9821 top-level cv-qualifiers, and the type to which the reference
9822 initialized by S2 refers is more cv-qualified than the type to
9823 which the reference initialized by S1 refers.
9825 DR 1328 [over.match.best]: the context is an initialization by
9826 conversion function for direct reference binding (13.3.1.6) of a
9827 reference to function type, the return type of F1 is the same kind of
9828 reference (i.e. lvalue or rvalue) as the reference being initialized,
9829 and the return type of F2 is not. */
9832 {
9839 {
9843 /* Don't prefer a bad conversion that drops cv-quals to a bad
9844 conversion with the wrong rvalueness. */
9848 }
9851 {
9855 {
9856 /* Prefer the one that drops fewer cv-quals. */
9861 }
9863 }
9864 }
9866 /* Neither conversion sequence is better than the other. */
9868 }
9870 /* The source type for this standard conversion sequence. */
9872 static tree
9874 {
9876 {
9881 }
9883 }
9885 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9886 a pointer to LOSER and re-running joust to produce the warning if WINNER
9887 is actually used. */
9889 static void
9891 {
9897 }
9899 /* Compare two candidates for overloading as described in
9900 [over.match.best]. Return values:
9902 1: cand1 is better than cand2
9903 -1: cand2 is better than cand1
9904 0: cand1 and cand2 are indistinguishable */
9906 static int
9908 tsubst_flags_t complain)
9909 {
9915 /* Candidates that involve bad conversions are always worse than those
9916 that don't. */
9922 /* If we have two pseudo-candidates for conversions to the same type,
9923 or two candidates for the same function, arbitrarily pick one. */
9928 /* Prefer a non-deleted function over an implicitly deleted move
9929 constructor or assignment operator. This differs slightly from the
9930 wording for issue 1402 (which says the move op is ignored by overload
9931 resolution), but this way produces better error messages. */
9935 {
9942 }
9944 /* a viable function F1
9945 is defined to be a better function than another viable function F2 if
9946 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9947 ICSi(F2), and then */
9949 /* for some argument j, ICSj(F1) is a better conversion sequence than
9950 ICSj(F2) */
9952 /* For comparing static and non-static member functions, we ignore
9953 the implicit object parameter of the non-static function. The
9954 standard says to pretend that the static function has an object
9955 parm, but that won't work with operator overloading. */
9958 {
9964 /* We're comparing a near-match list constructor and a near-match
9965 non-list constructor. Just treat them as unordered. */
9972 else
9973 {
9976 }
9977 }
9980 {
9986 {
9988 && warn_sign_promo
10000 {
10007 else
10012 {
10016 }
10017 else
10019 }
10022 {
10025 }
10027 }
10028 }
10030 /* warn about confusing overload resolution for user-defined conversions,
10031 either between a constructor and a conversion op, or between two
10032 conversion ops. */
10037 {
10043 else
10046 /* We don't want to complain about `X::operator T1 ()'
10047 beating `X::operator T2 () const', when T2 is a no less
10048 cv-qualified version of T1. */
10051 {
10056 {
10059 }
10062 }
10063 else
10069 {
10076 {
10078 }
10079 }
10080 else
10082 }
10087 /* DR 495 moved this tiebreaker above the template ones. */
10088 /* or, if not that,
10089 the context is an initialization by user-defined conversion (see
10090 _dcl.init_ and _over.match.user_) and the standard conversion
10091 sequence from the return type of F1 to the destination type (i.e.,
10092 the type of the entity being initialized) is a better conversion
10093 sequence than the standard conversion sequence from the return type
10094 of F2 to the destination type. */
10097 {
10101 }
10103 /* or, if not that,
10104 F1 is a non-template function and F2 is a template function
10105 specialization. */
10112 /* or, if not that,
10113 F1 and F2 are template functions and the function template for F1 is
10114 more specialized than the template for F2 according to the partial
10115 ordering rules. */
10118 {
10119 winner = more_specialized_fn
10122 /* [temp.func.order]: The presence of unused ellipsis and default
10123 arguments has no effect on the partial ordering of function
10124 templates. add_function_candidate() will not have
10125 counted the "this" argument for constructors. */
10129 }
10131 // C++ Concepts
10132 // or, if not that, F1 is more constrained than F2.
10134 {
10138 }
10140 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10142 {
10144 /* We distinguish between candidates from an explicit deduction guide and
10145 candidates built from a constructor based on DECL_ARTIFICIAL. */
10152 {
10153 /* Prefer the special copy guide over a declared copy/move
10154 constructor. */
10160 /* Prefer a candidate generated from a non-template constructor. */
10165 }
10166 }
10168 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10169 for all arguments the corresponding parameters of F1 and F2 have the same
10170 type (CWG 2273/2277). */
10175 {
10189 {
10191 {
10196 }
10199 }
10200 }
10202 /* Check whether we can discard a builtin candidate, either because we
10203 have two identical ones or matching builtin and non-builtin candidates.
10205 (Pedantically in the latter case the builtin which matched the user
10206 function should not be added to the overload set, but we spot it here.
10208 [over.match.oper]
10209 ... the builtin candidates include ...
10210 - do not have the same parameter type list as any non-template
10211 non-member candidate. */
10214 {
10220 {
10222 /* Two built-in candidates; arbitrarily pick one. */
10225 /* cand1 is built-in; prefer cand2. */
10227 else
10228 /* cand2 is built-in; prefer cand1. */
10230 }
10231 }
10233 /* For candidates of a multi-versioned function, make the version with
10234 the highest priority win. This version will be checked for dispatching
10235 first. If this version can be inlined into the caller, the front-end
10236 will simply make a direct call to this function. */
10242 {
10248 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10249 is possible that cand1->fn and cand2->fn are function versions but of
10250 different functions. Check types to see if they are versions of the same
10251 function. */
10254 {
10255 /* Always make the version with the higher priority, more
10256 specialized, win. */
10260 else
10262 }
10263 }
10265 /* If the two function declarations represent the same function (this can
10266 happen with declarations in multiple scopes and arg-dependent lookup),
10267 arbitrarily choose one. But first make sure the default args we're
10268 using match. */
10271 {
10278 {
10279 /* Don't crash if the fn is variadic. */
10284 }
10292 {
10295 {
10297 {
10299 {
10301 "default argument mismatch in "
10303 {
10308 }
10309 }
10310 else
10312 }
10313 else
10316 }
10319 }
10322 }
10324 tweak:
10326 /* Extension: If the worst conversion for one candidate is worse than the
10327 worst conversion for the other, take the first. */
10329 {
10334 {
10339 }
10345 {
10346 /* Don't choose a deleted function over ambiguity. */
10350 {
10352 "ISO C++ says that these are ambiguous, even "
10353 "though the worst conversion for the first is better than "
10357 }
10358 else
10361 }
10362 }
10366 }
10368 /* Given a list of candidates for overloading, find the best one, if any.
10369 This algorithm has a worst case of O(2n) (winner is last), and a best
10370 case of O(n/2) (totally ambiguous); much better than a sorting
10371 algorithm. */
10375 {
10380 /* Walk through the list once, comparing each current champ to the next
10381 candidate, knocking out a candidate or two with each comparison. */
10384 {
10388 else
10389 {
10391 {
10396 }
10397 else
10398 {
10401 }
10404 }
10405 }
10407 /* Make sure the champ is better than all the candidates it hasn't yet
10408 been compared to. */
10411 challenger != champ
10414 {
10418 }
10421 }
10423 /* Returns nonzero if things of type FROM can be converted to TO. */
10425 bool
10427 {
10429 /* implicit_conversion only considers user-defined conversions
10430 if it has an expression for the call argument list. */
10434 }
10436 /* Returns nonzero if things of type FROM can be converted to TO with a
10437 standard conversion. */
10439 bool
10441 {
10443 }
10445 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10447 bool
10449 tsubst_flags_t complain)
10450 {
10455 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10457 /* We want to discard any access checks done for this test,
10458 as we might not be in the appropriate access context and
10459 we'll do the check again when we actually perform the
10460 conversion. */
10467 /* Discard the access checks now. */
10469 /* Free all the conversions we allocated. */
10473 }
10475 /* Like can_convert_arg, but allows dubious conversions as well. */
10477 bool
10479 tsubst_flags_t complain)
10480 {
10484 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10486 /* Try to perform the conversion. */
10489 /* Free all the conversions we allocated. */
10493 }
10495 /* Convert EXPR to TYPE. Return the converted expression.
10497 Note that we allow bad conversions here because by the time we get to
10498 this point we are committed to doing the conversion. If we end up
10499 doing a bad conversion, convert_like will complain. */
10501 tree
10504 {
10512 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10520 {
10522 {
10523 /* If expr has unknown type, then it is an overloaded function.
10524 Call instantiate_type to get good error messages. */
10529 else
10532 }
10534 }
10536 {
10537 /* In a template, we are only concerned about determining the
10538 type of non-dependent expressions, so we do not have to
10539 perform the actual conversion. But for initializers, we
10540 need to be able to perform it at instantiation
10541 (or instantiate_non_dependent_expr) time. */
10545 }
10546 else
10549 /* Free all the conversions we allocated. */
10553 }
10555 tree
10557 {
10559 LOOKUP_IMPLICIT);
10560 }
10562 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10563 permitted. If the conversion is valid, the converted expression is
10564 returned. Otherwise, NULL_TREE is returned, except in the case
10565 that TYPE is a class type; in that case, an error is issued. If
10566 C_CAST_P is true, then this direct-initialization is taking
10567 place as part of a static_cast being attempted as part of a C-style
10568 cast. */
10570 tree
10572 tree expr,
10574 tsubst_flags_t complain)
10575 {
10581 /* [dcl.init]
10583 If the destination type is a (possibly cv-qualified) class type:
10585 -- If the initialization is direct-initialization ...,
10586 constructors are considered. ... If no constructor applies, or
10587 the overload resolution is ambiguous, the initialization is
10588 ill-formed. */
10590 {
10596 }
10598 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10602 c_cast_p,
10606 else
10609 c_cast_p,
10610 complain);
10612 /* Free all the conversions we allocated. */
10616 }
10618 /* When initializing a reference that lasts longer than a full-expression,
10619 this special rule applies:
10621 [class.temporary]
10623 The temporary to which the reference is bound or the temporary
10624 that is the complete object to which the reference is bound
10625 persists for the lifetime of the reference.
10627 The temporaries created during the evaluation of the expression
10628 initializing the reference, except the temporary to which the
10629 reference is bound, are destroyed at the end of the
10630 full-expression in which they are created.
10632 In that case, we store the converted expression into a new
10633 VAR_DECL in a new scope.
10635 However, we want to be careful not to create temporaries when
10636 they are not required. For example, given:
10638 struct B {};
10639 struct D : public B {};
10640 D f();
10641 const B& b = f();
10643 there is no need to copy the return value from "f"; we can just
10644 extend its lifetime. Similarly, given:
10646 struct S {};
10647 struct T { operator S(); };
10648 T t;
10649 const S& s = t;
10651 we can extend the lifetime of the return value of the conversion
10652 operator.
10654 The next several functions are involved in this lifetime extension. */
10656 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10657 reference is being bound to a temporary. Create and return a new
10658 VAR_DECL with the indicated TYPE; this variable will store the value to
10659 which the reference is bound. */
10661 tree
10663 {
10666 /* Register the variable. */
10669 {
10670 /* Namespace-scope or local static; give it a mangled name. */
10671 /* FIXME share comdat with decl? */
10682 }
10683 else
10684 /* Create a new cleanup level if necessary. */
10688 }
10690 /* EXPR is the initializer for a variable DECL of reference or
10691 std::initializer_list type. Create, push and return a new VAR_DECL
10692 for the initializer so that it will live as long as DECL. Any
10693 cleanup for the new variable is returned through CLEANUP, and the
10694 code to initialize the new variable is returned through INITP. */
10696 static tree
10699 {
10700 tree init;
10701 tree type;
10702 tree var;
10704 /* Create the temporary variable. */
10708 /* If the rvalue is the result of a function call it will be
10709 a TARGET_EXPR. If it is some other construct (such as a
10710 member access expression where the underlying object is
10711 itself the result of a function call), turn it into a
10712 TARGET_EXPR here. It is important that EXPR be a
10713 TARGET_EXPR below since otherwise the INIT_EXPR will
10714 attempt to make a bitwise copy of EXPR to initialize
10715 VAR. */
10721 {
10725 }
10727 /* Recursively extend temps in this initializer. */
10731 /* Any reference temp has a non-trivial initializer. */
10734 /* If the initializer is constant, put it in DECL_INITIAL so we get
10735 static initialization and use in constant expressions. */
10738 {
10740 {
10741 /* 5.19 says that a constant expression can include an
10742 lvalue-rvalue conversion applied to "a glvalue of literal type
10743 that refers to a non-volatile temporary object initialized
10744 with a constant expression". Rather than try to communicate
10745 that this VAR_DECL is a temporary, just mark it constexpr.
10747 Currently this is only useful for initializer_list temporaries,
10748 since reference vars can't appear in constant expressions. */
10752 }
10755 }
10756 else
10757 /* Create the INIT_EXPR that will initialize the temporary
10758 variable. */
10761 {
10766 else
10767 {
10771 }
10773 /* We must be careful to destroy the temporary only
10774 after its initialization has taken place. If the
10775 initialization throws an exception, then the
10776 destructor should not be run. We cannot simply
10777 transform INIT into something like:
10779 (INIT, ({ CLEANUP_STMT; }))
10781 because emit_local_var always treats the
10782 initializer as a full-expression. Thus, the
10783 destructor would run too early; it would run at the
10784 end of initializing the reference variable, rather
10785 than at the end of the block enclosing the
10786 reference variable.
10788 The solution is to pass back a cleanup expression
10789 which the caller is responsible for attaching to
10790 the statement tree. */
10791 }
10792 else
10793 {
10796 {
10799 tls_aggregates);
10800 else
10802 static_aggregates);
10803 }
10804 else
10805 /* Check whether the dtor is callable. */
10807 }
10808 /* Avoid -Wunused-variable warning (c++/38958). */
10815 }
10817 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10818 initializing a variable of that TYPE. */
10820 tree
10823 {
10831 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10837 {
10839 {
10848 else
10852 }
10854 }
10857 /* Perform the conversion. */
10860 /* We gave an error in build_user_type_conversion_1. */
10862 else
10865 /* Free all the conversions we allocated. */
10869 }
10871 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10872 which is bound either to a reference or a std::initializer_list. */
10874 static tree
10876 {
10881 {
10885 }
10888 /* Deal with binding to a subobject. */
10892 {
10900 }
10902 }
10904 /* INIT is part of the initializer for DECL. If there are any
10905 reference or initializer lists being initialized, extend their
10906 lifetime to match that of DECL. */
10908 tree
10910 {
10916 else
10917 {
10922 {
10924 {
10925 /* The temporary array underlying a std::initializer_list
10926 is handled like a reference temporary. */
10930 }
10931 else
10932 {
10938 }
10942 }
10943 }
10946 }
10948 /* Returns true iff an initializer for TYPE could contain temporaries that
10949 need to be extended because they are bound to references or
10950 std::initializer_list. */
10952 bool
10954 {
10959 {
10966 }
10968 }
10970 /* Returns true iff TYPE is some variant of std::initializer_list. */
10972 bool
10974 {
10979 /* Look through typedefs. */
10984 }
10986 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10987 will accept an argument list of a single std::initializer_list<T>. */
10989 bool
10991 {
10993 tree arg;
11005 /* There are more non-defaulted parms. */
11009 }