| blob | e04626863af5cde497c83f7d10ce26155a3ab299 |
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 }
379 /* Don't pass empty class objects by value. This is useful
380 for tags in STL, which are used to control overload resolution.
381 We don't need to handle other cases of copying empty classes. */
384 {
388 {
392 }
393 }
396 }
398 /* New overloading code. */
405 };
407 /* Information for providing diagnostics about why overloading failed. */
410 rr_none,
411 rr_arity,
412 rr_explicit_conversion,
413 rr_template_conversion,
414 rr_arg_conversion,
415 rr_bad_arg_conversion,
416 rr_template_unification,
417 rr_invalid_copy,
418 rr_inherited_ctor,
419 rr_constraint_failure
420 };
423 /* The index of the argument, 0-based. */
425 /* The actual argument or its type. */
426 tree from;
427 /* The type of the parameter. */
428 tree to_type;
429 };
434 /* Information about an arity mismatch. */
436 /* The expected number of arguments. */
438 /* The actual number of arguments in the call. */
440 /* Whether the call was a varargs call. */
443 /* Information about an argument conversion mismatch. */
445 /* Same, but for bad argument conversions. */
447 /* Information about template unification failures. These are the
448 parameters passed to fn_type_unification. */
450 tree tmpl;
451 tree explicit_targs;
455 tree return_type;
456 unification_kind_t strict;
459 /* Information about template instantiation failures. These are the
460 parameters passed to instantiate_template. */
462 tree tmpl;
463 tree targs;
466 };
469 /* The FUNCTION_DECL that will be called if this candidate is
470 selected by overload resolution. */
471 tree fn;
472 /* If not NULL_TREE, the first argument to use when calling this
473 function. */
474 tree first_arg;
475 /* The rest of the arguments to use when calling this function. If
476 there are no further arguments this may be NULL or it may be an
477 empty vector. */
479 /* The implicit conversion sequences for each of the arguments to
480 FN. */
482 /* The number of implicit conversion sequences. */
484 /* If FN is a user-defined conversion, the standard conversion
485 sequence from the type returned by FN to the desired destination
486 type. */
489 /* If FN is a member function, the binfo indicating the path used to
490 qualify the name of FN at the call site. This path is used to
491 determine whether or not FN is accessible if it is selected by
492 overload resolution. The DECL_CONTEXT of FN will always be a
493 (possibly improper) base of this binfo. */
494 tree access_path;
495 /* If FN is a non-static member function, the binfo indicating the
496 subobject to which the `this' pointer should be converted if FN
497 is selected by overload resolution. The type pointed to by
498 the `this' pointer must correspond to the most derived class
499 indicated by the CONVERSION_PATH. */
500 tree conversion_path;
501 tree template_decl;
502 tree explicit_targs;
507 /* The flags active in add_candidate. */
509 };
511 /* Returns true iff T is a null pointer constant in the sense of
512 [conv.ptr]. */
514 bool
516 {
519 /* [conv.ptr]
521 A null pointer constant is an integral constant expression
522 (_expr.const_) rvalue of integer type that evaluates to zero or
523 an rvalue of type std::nullptr_t. */
528 {
529 /* Core issue 903 says only literal 0 is a null pointer constant. */
536 }
538 {
543 }
546 }
548 /* Returns true iff T is a null member pointer value (4.11). */
550 bool
552 {
561 else
563 }
565 /* Returns nonzero if PARMLIST consists of only default parms,
566 ellipsis, and/or undeduced parameter packs. */
568 bool
570 {
577 }
579 /* Allocate N bytes of memory from the conversion obstack. The memory
580 is zeroed before being returned. */
584 {
587 {
590 }
594 }
596 /* Allocate rejection reasons. */
600 {
605 }
609 {
615 }
619 {
626 }
630 {
637 }
641 {
647 }
651 {
657 }
664 {
671 /* Copy args to our own storage. */
679 }
683 {
685 }
689 {
692 }
696 {
699 }
701 // Build a constraint failure record, saving information into the
702 // template_instantiation field of the rejection. If FN is not a template
703 // declaration, the TMPL member is the FN declaration and TARGS is empty.
707 {
710 {
713 }
714 else
715 {
718 }
720 }
722 /* Dynamically allocate a conversion. */
726 {
731 }
733 /* Make sure that all memory on the conversion obstack has been
734 freed. */
736 void
738 {
742 }
744 /* Dynamically allocate an array of N conversions. */
748 {
750 }
754 {
758 /* Note that the caller is responsible for filling in t->cand for
759 user-defined conversions. */
765 {
782 }
788 }
790 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
791 specialization of std::initializer_list<T>, if such a conversion is
792 possible. */
796 {
802 tree val;
804 /* Within a list-initialization we can have more user-defined
805 conversions. */
807 /* But no narrowing conversions. */
810 /* Can't make an array of these types. */
817 {
818 conversion *sub
825 }
833 {
841 }
844 }
846 /* Return the next conversion of the conversion chain (if applicable),
847 or NULL otherwise. Please use this function instead of directly
848 accessing fields of struct conversion. */
852 {
859 }
861 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
862 is a valid aggregate initializer for array type ATYPE. */
864 static bool
866 {
870 {
876 else
878 complain);
881 }
883 }
885 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
886 aggregate class, if such a conversion is possible. */
890 {
896 /* We already called reshape_init in implicit_conversion. */
898 /* The conversions within the init-list aren't affected by the enclosing
899 context; they're always simple copy-initialization. */
903 {
905 tree val;
913 /* Value-initialization of reference is ill-formed. */
915 else
916 {
920 }
926 else
928 complain);
935 }
947 }
949 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
950 array type, if such a conversion is possible. */
954 {
959 tree val;
964 /* We might need to propagate the size from the element to the array. */
969 {
973 }
978 {
979 conversion *sub
991 }
1000 }
1002 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1003 complex type, if such a conversion is possible. */
1007 tsubst_flags_t complain)
1008 {
1013 tree val;
1024 {
1025 conversion *sub
1037 }
1046 }
1048 /* Build a representation of the identity conversion from EXPR to
1049 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1053 {
1061 }
1063 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1064 were multiple user-defined conversions to accomplish the job.
1065 Build a conversion that indicates that ambiguity. */
1069 {
1077 }
1079 tree
1081 {
1085 }
1087 /* Returns the standard conversion path (see [conv]) from type FROM to type
1088 TO, if any. For proper handling of null pointer constants, you must
1089 also pass the expression EXPR to convert from. If C_CAST_P is true,
1090 this conversion is coming from a C-style cast. */
1095 {
1099 tree qualified_to;
1103 {
1106 }
1112 {
1114 {
1120 }
1122 {
1123 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1126 }
1127 }
1134 {
1138 }
1139 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1140 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1141 express the copy constructor call required by copy-initialization. */
1143 {
1145 {
1146 tree bitfield_type;
1149 {
1152 }
1153 }
1156 /* Tell convert_like_real to set LOOKUP_PREFER_RVALUE. */
1158 }
1160 /* Allow conversion between `__complex__' data types. */
1162 {
1163 /* The standard conversion sequence to convert FROM to TO is
1164 the standard conversion sequence to perform componentwise
1165 conversion. */
1168 complain);
1171 {
1174 }
1175 else
1179 }
1182 {
1186 }
1188 /* [conv.ptr]
1189 A null pointer constant can be converted to a pointer type; ... A
1190 null pointer constant of integral type can be converted to an
1191 rvalue of type std::nullptr_t. */
1199 {
1200 /* For backwards brain damage compatibility, allow interconversion of
1201 pointers and integers with a pedwarn. */
1204 }
1206 {
1207 /* For backwards brain damage compatibility, allow interconversion of
1208 enums and integers with a pedwarn. */
1211 }
1214 {
1215 tree to_pointee;
1216 tree from_pointee;
1219 {
1223 /* Since this is the target of a pointer, it can't have function
1224 qualifiers, so any TYPE_QUALS must be for attributes const or
1225 noreturn. Strip them. */
1232 }
1233 else
1234 {
1237 }
1241 to_pointee))
1242 ;
1246 {
1248 /* Don't try to apply restrict to void. */
1253 }
1255 {
1262 && (same_type_ignoring_top_level_qualifiers_p
1264 {
1267 }
1268 else
1270 }
1273 /* [conv.ptr]
1275 An rvalue of type "pointer to cv D," where D is a
1276 class type, can be converted to an rvalue of type
1277 "pointer to cv B," where B is a base class (clause
1278 _class.derived_) of D. If B is an inaccessible
1279 (clause _class.access_) or ambiguous
1280 (_class.member.lookup_) base class of D, a program
1281 that necessitates this conversion is ill-formed.
1282 Therefore, we use DERIVED_FROM_P, and do not check
1283 access or uniqueness. */
1285 {
1286 from_pointee
1292 }
1297 /* In a C-style cast, we ignore CV-qualification because we
1298 are allowed to perform a static_cast followed by a
1299 const_cast. */
1304 /* converting from string constant to char *. */
1308 /* Allow conversions among compatible ObjC pointer types (base
1309 conversions have been already handled above). */
1314 {
1317 }
1318 else
1322 }
1324 {
1338 else
1342 {
1344 tbase,
1350 }
1353 }
1355 {
1356 /* [conv.bool]
1358 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1359 to member type can be converted to a prvalue of type bool. ...
1360 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1361 std::nullptr_t can be converted to a prvalue of type bool; */
1367 {
1378 }
1381 }
1382 /* We don't check for ENUMERAL_TYPE here because there are no standard
1383 conversions to enum type. */
1384 /* As an extension, allow conversion to complex type. */
1386 {
1393 /* Give this a better rank if it's a promotion. */
1397 }
1403 {
1407 /* The derived-to-base conversion indicates the initialization
1408 of a parameter with base type from an object of a derived
1409 type. A temporary object is created to hold the result of
1410 the conversion unless we're binding directly to a reference. */
1412 }
1413 else
1420 }
1422 /* Returns nonzero if T1 is reference-related to T2. */
1424 bool
1426 {
1433 /* [dcl.init.ref]
1435 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1436 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1437 of T2. */
1441 }
1443 /* Returns nonzero if T1 is reference-compatible with T2. */
1445 static bool
1447 {
1448 /* [dcl.init.ref]
1450 "cv1 T1" is reference compatible with "cv2 T2" if
1451 * T1 is reference-related to T2 or
1452 * T2 is "noexcept function" and T1 is "function", where the
1453 function types are otherwise the same,
1454 and cv1 is the same cv-qualification as, or greater cv-qualification
1455 than, cv2. */
1459 }
1461 /* A reference of the indicated TYPE is being bound directly to the
1462 expression represented by the implicit conversion sequence CONV.
1463 Return a conversion sequence for this binding. */
1467 {
1468 tree t;
1475 /* [over.ics.rank]
1477 When a parameter of reference type binds directly
1478 (_dcl.init.ref_) to an argument expression, the implicit
1479 conversion sequence is the identity conversion, unless the
1480 argument expression has a type that is a derived class of the
1481 parameter type, in which case the implicit conversion sequence is
1482 a derived-to-base Conversion.
1484 If the parameter binds directly to the result of applying a
1485 conversion function to the argument expression, the implicit
1486 conversion sequence is a user-defined conversion sequence
1487 (_over.ics.user_), with the second standard conversion sequence
1488 either an identity conversion or, if the conversion function
1489 returns an entity of a type that is a derived class of the
1490 parameter type, a derived-to-base conversion. */
1492 {
1493 /* Represent the derived-to-base conversion. */
1495 /* We will actually be binding to the base-class subobject in
1496 the derived class, so we mark this conversion appropriately.
1497 That way, convert_like knows not to generate a temporary. */
1499 }
1501 }
1503 /* Returns the conversion path from type FROM to reference type TO for
1504 purposes of reference binding. For lvalue binding, either pass a
1505 reference type to FROM or an lvalue expression to EXPR. If the
1506 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1507 the conversion returned. If C_CAST_P is true, this
1508 conversion is coming from a C-style cast. */
1512 tsubst_flags_t complain)
1513 {
1517 tree tfrom;
1520 cp_lvalue_kind gl_kind;
1524 {
1529 }
1532 {
1534 /* DR 1288: Otherwise, if the initializer list has a single element
1535 of type E and ... [T's] referenced type is reference-related to E,
1536 the object or reference is initialized from that element... */
1538 {
1544 {
1548 }
1549 }
1550 /* Otherwise, if T is a reference type, a prvalue temporary of the
1551 type referenced by T is copy-list-initialized or
1552 direct-list-initialized, depending on the kind of initialization
1553 for the reference, and the reference is bound to that temporary. */
1556 skip:;
1557 }
1560 {
1565 else
1567 }
1573 else
1576 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1581 /* Same mask as real_lvalue_p. */
1588 /* Figure out whether or not the types are reference-related and
1589 reference compatible. We have to do this after stripping
1590 references from FROM. */
1592 /* If this is a C cast, first convert to an appropriately qualified
1593 type, so that we can later do a const_cast to the desired type. */
1599 /* Directly bind reference when target expression's type is compatible with
1600 the reference and expression is an lvalue. In DR391, the wording in
1601 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1602 const and rvalue references to rvalues of compatible class type.
1603 We should also do direct bindings for non-class xvalues. */
1605 {
1606 /* [dcl.init.ref]
1608 If the initializer expression
1610 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1611 is reference-compatible with "cv2 T2,"
1613 the reference is bound directly to the initializer expression
1614 lvalue.
1616 [...]
1617 If the initializer expression is an rvalue, with T2 a class type,
1618 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1619 is bound to the object represented by the rvalue or to a sub-object
1620 within that object. */
1626 /* Handle rvalue reference to function properly. */
1627 conv->rvaluedness_matches_p
1629 else
1630 conv->rvaluedness_matches_p
1635 /* For the purposes of overload resolution, we ignore the fact
1636 this expression is a bitfield or packed field. (In particular,
1637 [over.ics.ref] says specifically that a function with a
1638 non-const reference parameter is viable even if the
1639 argument is a bitfield.)
1641 However, when we actually call the function we must create
1642 a temporary to which to bind the reference. If the
1643 reference is volatile, or isn't const, then we cannot make
1644 a temporary, so we just issue an error when the conversion
1645 actually occurs. */
1648 /* Don't allow binding of lvalues (other than function lvalues) to
1649 rvalue references. */
1654 /* Nor the reverse. */
1665 }
1666 /* [class.conv.fct] A conversion function is never used to convert a
1667 (possibly cv-qualified) object to the (possibly cv-qualified) same
1668 object type (or a reference to it), to a (possibly cv-qualified) base
1669 class of that type (or a reference to it).... */
1672 {
1673 /* [dcl.init.ref]
1675 If the initializer expression
1677 -- has a class type (i.e., T2 is a class type) can be
1678 implicitly converted to an lvalue of type "cv3 T3," where
1679 "cv1 T1" is reference-compatible with "cv3 T3". (this
1680 conversion is selected by enumerating the applicable
1681 conversion functions (_over.match.ref_) and choosing the
1682 best one through overload resolution. (_over.match_).
1684 the reference is bound to the lvalue result of the conversion
1685 in the second case. */
1687 complain);
1690 }
1692 /* From this point on, we conceptually need temporaries, even if we
1693 elide them. Only the cases above are "direct bindings". */
1697 /* [over.ics.rank]
1699 When a parameter of reference type is not bound directly to an
1700 argument expression, the conversion sequence is the one required
1701 to convert the argument expression to the underlying type of the
1702 reference according to _over.best.ics_. Conceptually, this
1703 conversion sequence corresponds to copy-initializing a temporary
1704 of the underlying type with the argument expression. Any
1705 difference in top-level cv-qualification is subsumed by the
1706 initialization itself and does not constitute a conversion. */
1708 /* [dcl.init.ref]
1710 Otherwise, the reference shall be an lvalue reference to a
1711 non-volatile const type, or the reference shall be an rvalue
1712 reference.
1714 We try below to treat this as a bad conversion to improve diagnostics,
1715 but if TO is an incomplete class, we need to reject this conversion
1716 now to avoid unnecessary instantiation. */
1721 /* We're generating a temporary now, but don't bind any more in the
1722 conversion (specifically, don't slice the temporary returned by a
1723 conversion operator). */
1726 /* Core issue 899: When [copy-]initializing a temporary to be bound
1727 to the first parameter of a copy constructor (12.8) called with
1728 a single argument in the context of direct-initialization,
1729 explicit conversion functions are also considered.
1731 So don't set LOOKUP_ONLYCONVERTING in that case. */
1742 {
1743 /* If initializing the temporary used a conversion function,
1744 recalculate the second conversion sequence. */
1748 {
1751 conversion *new_second
1757 }
1758 }
1761 /* This reference binding, unlike those above, requires the
1762 creation of a temporary. */
1766 /* [dcl.init.ref]
1768 Otherwise, the reference shall be an lvalue reference to a
1769 non-volatile const type, or the reference shall be an rvalue
1770 reference. */
1774 /* [dcl.init.ref]
1776 Otherwise, a temporary of type "cv1 T1" is created and
1777 initialized from the initializer expression using the rules for a
1778 non-reference copy initialization. If T1 is reference-related to
1779 T2, cv1 must be the same cv-qualification as, or greater
1780 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1785 }
1787 /* Returns the implicit conversion sequence (see [over.ics]) from type
1788 FROM to type TO. The optional expression EXPR may affect the
1789 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1790 true, this conversion is coming from a C-style cast. */
1795 {
1802 /* Other flags only apply to the primary function in overload
1803 resolution, or after we've chosen one. */
1808 /* FIXME: actually we don't want warnings either, but we can't just
1809 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1810 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1811 We really ought not to issue that warning until we've committed
1812 to that conversion. */
1815 /* Call reshape_init early to remove redundant braces. */
1820 {
1825 }
1829 else
1836 {
1840 /* As an extension, allow list-initialization of _Complex. */
1842 {
1846 }
1848 /* Allow conversion from an initializer-list with one element to a
1849 scalar type. */
1851 {
1853 tree elt;
1859 else
1865 {
1868 /* Too many levels of braces, i.e. '{{1}}'. */
1871 }
1872 }
1875 }
1881 {
1891 {
1895 {
1896 /* "If C is not an initializer-list constructor and the
1897 initializer list has a single element of type cv U, where U is
1898 X or a class derived from X, the implicit conversion sequence
1899 has Exact Match rank if U is X, or Conversion rank if U is
1900 derived from X." */
1906 }
1908 }
1910 /* We used to try to bind a reference to a temporary here, but that
1911 is now handled after the recursive call to this function at the end
1912 of reference_binding. */
1914 }
1917 }
1919 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1920 functions. ARGS will not be changed until a single candidate is
1921 selected. */
1930 {
1948 }
1950 /* Return the number of remaining arguments in the parameter list
1951 beginning with ARG. */
1953 int
1955 {
1960 n++;
1963 }
1965 /* Create an overload candidate for the function or method FN called
1966 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1967 FLAGS is passed on to implicit_conversion.
1969 This does not change ARGS.
1971 CTYPE, if non-NULL, is the type we want to pretend this function
1972 comes from for purposes of overload resolution. */
1979 tsubst_flags_t complain)
1980 {
1984 tree parmnode;
1990 /* At this point we should not see any functions which haven't been
1991 explicitly declared, except for friend functions which will have
1992 been found using argument dependent lookup. */
1995 /* The `this', `in_chrg' and VTT arguments to constructors are not
1996 considered in overload resolution. */
1998 {
2000 /* Bring back parameters omitted from an inherited ctor. */
2002 else
2006 {
2009 }
2010 }
2011 else
2017 /* 13.3.2 - Viable functions [over.match.viable]
2018 First, to be a viable function, a candidate function shall have enough
2019 parameters to agree in number with the arguments in the list.
2021 We need to check this first; otherwise, checking the ICSes might cause
2022 us to produce an ill-formed template instantiation. */
2026 {
2030 }
2034 {
2038 }
2040 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2041 parameter of type "reference to cv C" (including such a constructor
2042 instantiated from a template) is excluded from the set of candidate
2043 functions when used to construct an object of type D with an argument list
2044 containing a single argument if C is reference-related to D. */
2046 && flag_new_inheriting_ctors
2048 {
2054 {
2057 }
2058 }
2060 /* Second, for a function to be viable, its constraints must be
2061 satisfied. */
2064 {
2067 }
2069 /* When looking for a function from a subobject from an implicit
2070 copy/move constructor/operator=, don't consider anything that takes (a
2071 reference to) an unrelated type. See c++/44909 and core 1092. */
2073 {
2079 else
2082 {
2085 ctype))
2087 }
2089 /* This only applies at the top level. */
2091 }
2096 /* Third, for F to be a viable function, there shall exist for each
2097 argument an implicit conversion sequence that converts that argument
2098 to the corresponding parameter of F. */
2103 {
2105 tree arg;
2114 else
2123 {
2129 /* The type of the implicit object parameter ('this') for
2130 overload resolution is not always the same as for the
2131 function itself; conversion functions are considered to
2132 be members of the class being converted, and functions
2133 introduced by a using-declaration are considered to be
2134 members of the class that uses them.
2136 Since build_over_call ignores the ICS for the `this'
2137 parameter, we can just change the parm type. */
2139 {
2140 parmtype = cp_build_qualified_type
2143 {
2144 /* If the function has a ref-qualifier, the implicit
2145 object parameter has reference type. */
2148 /* The special handling of 'this' conversions in compare_ics
2149 does not apply if there is a ref-qualifier. */
2151 }
2152 else
2153 {
2155 /* We don't use build_this here because we don't want to
2156 capture the object argument until we've chosen a
2157 non-static member function. */
2160 }
2161 }
2163 /* Core issue 899: When [copy-]initializing a temporary to be bound
2164 to the first parameter of a copy constructor (12.8) called with
2165 a single argument in the context of direct-initialization,
2166 explicit conversion functions are also considered.
2168 So set LOOKUP_COPY_PARM to let reference_binding know that
2169 it's being called in that context. We generalize the above
2170 to handle move constructors and template constructors as well;
2171 the standardese should soon be updated similarly. */
2175 && (same_type_ignoring_top_level_qualifiers_p
2177 {
2180 /* We allow user-defined conversions within init-lists, but
2181 don't list-initialize the copy parm, as that would mean
2182 using two levels of braces for the same type. */
2186 }
2187 else
2193 }
2194 else
2195 {
2199 }
2206 {
2210 }
2213 {
2216 }
2217 }
2219 out:
2222 }
2224 /* Create an overload candidate for the conversion function FN which will
2225 be invoked for expression OBJ, producing a pointer-to-function which
2226 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2227 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2228 passed on to implicit_conversion.
2230 Actually, we don't really care about FN; we care about the type it
2231 converts to. There may be multiple conversion functions that will
2232 convert to that type, and we rely on build_user_type_conversion_1 to
2233 choose the best one; so when we create our candidate, we record the type
2234 instead of the function. */
2240 tsubst_flags_t complain)
2241 {
2259 /* Don't bother looking up the same type twice. */
2264 {
2270 else
2275 {
2278 /* Leave the 'cand' field null; we'll figure out the conversion in
2279 convert_like_real if this candidate is chosen. */
2281 }
2285 {
2289 }
2290 else
2291 {
2295 }
2302 {
2305 }
2312 }
2316 {
2320 }
2324 }
2326 static void
2330 {
2344 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2345 conversion ops are allowed. We handle that here by just checking for
2346 boolean_type_node because other operators don't ask for it. COND_EXPR
2347 also does contextual conversion to bool for the first operand, but we
2348 handle that in build_conditional_expr, and type1 here is operand 2. */
2353 {
2360 {
2362 /* We need something for printing the candidate. */
2366 }
2368 {
2372 }
2374 }
2376 /* For COND_EXPR we rearranged the arguments; undo that now. */
2378 {
2383 complain);
2386 else
2387 {
2390 boolean_type_node);
2391 }
2392 }
2399 }
2401 static bool
2403 {
2405 }
2407 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2409 static bool
2411 {
2412 /* [over.built]
2414 In this section, the term promoted integral type is used to refer
2415 to those integral types which are preserved by integral promotion
2416 (including e.g. int and long but excluding e.g. char).
2417 Similarly, the term promoted arithmetic type refers to promoted
2418 integral types plus floating types. */
2422 }
2424 /* Create any builtin operator overload candidates for the operator in
2425 question given the converted operand types TYPE1 and TYPE2. The other
2426 args are passed through from add_builtin_candidates to
2427 build_builtin_candidate.
2429 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2430 If CODE is requires candidates operands of the same type of the kind
2431 of which TYPE1 and TYPE2 are, we add both candidates
2432 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2434 static void
2438 tsubst_flags_t complain)
2439 {
2441 {
2449 }
2452 {
2454 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2455 and VQ is either volatile or empty, there exist candidate operator
2456 functions of the form
2457 VQ T& operator++(VQ T&);
2458 T operator++(VQ T&, int);
2459 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2460 type other than bool, and VQ is either volatile or empty, there exist
2461 candidate operator functions of the form
2462 VQ T& operator--(VQ T&);
2463 T operator--(VQ T&, int);
2464 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2465 complete object type, and VQ is either volatile or empty, there exist
2466 candidate operator functions of the form
2467 T*VQ& operator++(T*VQ&);
2468 T*VQ& operator--(T*VQ&);
2469 T* operator++(T*VQ&, int);
2470 T* operator--(T*VQ&, int); */
2476 /* FALLTHRU */
2480 {
2483 }
2486 /* 7 For every cv-qualified or cv-unqualified object type T, there
2487 exist candidate operator functions of the form
2489 T& operator*(T*);
2491 8 For every function type T, there exist candidate operator functions of
2492 the form
2493 T& operator*(T*); */
2502 /* 9 For every type T, there exist candidate operator functions of the form
2503 T* operator+(T*);
2505 10For every promoted arithmetic type T, there exist candidate operator
2506 functions of the form
2507 T operator+(T);
2508 T operator-(T); */
2513 /* FALLTHRU */
2519 /* 11For every promoted integral type T, there exist candidate operator
2520 functions of the form
2521 T operator~(T); */
2528 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2529 is the same type as C2 or is a derived class of C2, T is a complete
2530 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2531 there exist candidate operator functions of the form
2532 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2533 where CV12 is the union of CV1 and CV2. */
2537 {
2545 }
2548 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2549 didate operator functions of the form
2550 LR operator*(L, R);
2551 LR operator/(L, R);
2552 LR operator+(L, R);
2553 LR operator-(L, R);
2554 bool operator<(L, R);
2555 bool operator>(L, R);
2556 bool operator<=(L, R);
2557 bool operator>=(L, R);
2558 bool operator==(L, R);
2559 bool operator!=(L, R);
2560 where LR is the result of the usual arithmetic conversions between
2561 types L and R.
2563 14For every pair of types T and I, where T is a cv-qualified or cv-
2564 unqualified complete object type and I is a promoted integral type,
2565 there exist candidate operator functions of the form
2566 T* operator+(T*, I);
2567 T& operator[](T*, I);
2568 T* operator-(T*, I);
2569 T* operator+(I, T*);
2570 T& operator[](I, T*);
2572 15For every T, where T is a pointer to complete object type, there exist
2573 candidate operator functions of the form112)
2574 ptrdiff_t operator-(T, T);
2576 16For every pointer or enumeration type T, there exist candidate operator
2577 functions of the form
2578 bool operator<(T, T);
2579 bool operator>(T, T);
2580 bool operator<=(T, T);
2581 bool operator>=(T, T);
2582 bool operator==(T, T);
2583 bool operator!=(T, T);
2585 17For every pointer to member type T, there exist candidate operator
2586 functions of the form
2587 bool operator==(T, T);
2588 bool operator!=(T, T); */
2595 {
2598 }
2599 /* FALLTHRU */
2612 {
2615 }
2617 {
2620 }
2621 /* Fall through. */
2637 {
2640 }
2643 {
2646 }
2652 /* FALLTHRU */
2655 {
2658 }
2660 {
2663 }
2666 /* 18For every pair of promoted integral types L and R, there exist candi-
2667 date operator functions of the form
2668 LR operator%(L, R);
2669 LR operator&(L, R);
2670 LR operator^(L, R);
2671 LR operator|(L, R);
2672 L operator<<(L, R);
2673 L operator>>(L, R);
2674 where LR is the result of the usual arithmetic conversions between
2675 types L and R. */
2683 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2687 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2688 type, VQ is either volatile or empty, and R is a promoted arithmetic
2689 type, there exist candidate operator functions of the form
2690 VQ L& operator=(VQ L&, R);
2691 VQ L& operator*=(VQ L&, R);
2692 VQ L& operator/=(VQ L&, R);
2693 VQ L& operator+=(VQ L&, R);
2694 VQ L& operator-=(VQ L&, R);
2696 20For every pair T, VQ), where T is any type and VQ is either volatile
2697 or empty, there exist candidate operator functions of the form
2698 T*VQ& operator=(T*VQ&, T*);
2700 21For every pair T, VQ), where T is a pointer to member type and VQ is
2701 either volatile or empty, there exist candidate operator functions of
2702 the form
2703 VQ T& operator=(VQ T&, T);
2705 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2706 unqualified complete object type, VQ is either volatile or empty, and
2707 I is a promoted integral type, there exist candidate operator func-
2708 tions of the form
2709 T*VQ& operator+=(T*VQ&, I);
2710 T*VQ& operator-=(T*VQ&, I);
2712 23For every triple L, VQ, R), where L is an integral or enumeration
2713 type, VQ is either volatile or empty, and R is a promoted integral
2714 type, there exist candidate operator functions of the form
2716 VQ L& operator%=(VQ L&, R);
2717 VQ L& operator<<=(VQ L&, R);
2718 VQ L& operator>>=(VQ L&, R);
2719 VQ L& operator&=(VQ L&, R);
2720 VQ L& operator^=(VQ L&, R);
2721 VQ L& operator|=(VQ L&, R); */
2725 {
2729 {
2732 }
2733 /* FALLTHRU */
2746 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2759 {
2762 }
2767 }
2772 /* [over.built]
2774 For every pair of promoted arithmetic types L and R, there
2775 exist candidate operator functions of the form
2777 LR operator?(bool, L, R);
2779 where LR is the result of the usual arithmetic conversions
2780 between types L and R.
2782 For every type T, where T is a pointer or pointer-to-member
2783 type, there exist candidate operator functions of the form T
2784 operator?(bool, T, T); */
2788 /* That's OK. */
2791 /* Otherwise, the types should be pointers. */
2795 /* We don't check that the two types are the same; the logic
2796 below will actually create two candidates; one in which both
2797 parameter types are TYPE1, and one in which both parameter
2798 types are TYPE2. */
2809 }
2811 /* Make sure we don't create builtin candidates with dependent types. */
2815 {
2816 /* Try to recover if one of the types is non-dependent. But if
2817 there's only one type, there's nothing we can do. */
2820 /* And we lose if both are dependent. */
2823 /* Or if they have different forms. */
2831 }
2833 /* If we're dealing with two pointer types or two enumeral types,
2834 we need candidates for both of them. */
2843 {
2845 {
2847 error_mark_node,
2848 error_mark_node,
2849 CPO_CONVERSION,
2850 tf_none);
2852 {
2853 build_builtin_candidate
2857 }
2858 }
2860 build_builtin_candidate
2862 build_builtin_candidate
2865 }
2867 build_builtin_candidate
2869 }
2871 tree
2873 {
2879 }
2881 /* There are three conditions of builtin candidates:
2883 1) bool-taking candidates. These are the same regardless of the input.
2884 2) pointer-pair taking candidates. These are generated for each type
2885 one of the input types converts to.
2886 3) arithmetic candidates. According to the standard, we should generate
2887 all of these, but I'm trying not to...
2889 Here we generate a superset of the possible candidates for this particular
2890 case. That is a subset of the full set the standard defines, plus some
2891 other cases which the standard disallows. add_builtin_candidate will
2892 filter out the invalid set. */
2894 static void
2898 {
2902 /* TYPES[i] is the set of possible builtin-operator parameter types
2903 we will consider for the Ith argument. */
2908 {
2911 else
2913 }
2916 {
2917 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2918 and VQ is either volatile or empty, there exist candidate operator
2919 functions of the form
2920 VQ T& operator++(VQ T&); */
2930 /* 24There also exist candidate operator functions of the form
2931 bool operator!(bool);
2932 bool operator&&(bool, bool);
2933 bool operator||(bool, bool); */
2936 build_builtin_candidate
2943 build_builtin_candidate
2961 /* Fall through. */
2965 }
2971 {
2973 ;
2975 {
2976 tree convs;
2984 {
2989 }
2995 {
3008 {
3014 }
3018 }
3019 }
3020 else
3021 {
3026 {
3032 }
3034 }
3035 }
3037 /* Run through the possible parameter types of both arguments,
3038 creating candidates with those parameter types. */
3040 {
3042 tree u;
3046 add_builtin_candidate
3049 else
3050 add_builtin_candidate
3053 }
3057 }
3060 /* If TMPL can be successfully instantiated as indicated by
3061 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3063 TMPL is the template. EXPLICIT_TARGS are any explicit template
3064 arguments. ARGLIST is the arguments provided at the call-site.
3065 This does not change ARGLIST. The RETURN_TYPE is the desired type
3066 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3067 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3068 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3076 tsubst_flags_t complain)
3077 {
3087 tree arg;
3089 tree fn;
3093 /* We don't do deduction on the in-charge parameter, the VTT
3094 parameter or 'this'. */
3096 {
3100 /* We're deducing for a call to the result of a template conversion
3102 else
3104 }
3109 {
3112 else
3114 }
3122 {
3123 /* 12.8/6 says, "A declaration of a constructor for a class X is
3124 ill-formed if its first parameter is of type (optionally cv-qualified)
3125 X and either there are no other parameters or else all other
3126 parameters have default arguments. A member function template is never
3127 instantiated to produce such a constructor signature."
3129 So if we're trying to copy an object of the containing class, don't
3130 consider a template constructor that has a first parameter type that
3131 is just a template parameter, as we would deduce a signature that we
3132 would then reject in the code below. */
3134 {
3139 {
3143 }
3144 }
3145 }
3152 {
3155 }
3159 {
3162 }
3167 args_without_in_chrg,
3168 nargs_without_in_chrg,
3173 {
3174 /* Don't repeat unification later if it already resulted in errors. */
3178 nargs_without_in_chrg,
3180 else
3183 }
3186 {
3189 ctype))
3190 {
3191 /* We're trying to produce a constructor with a prohibited signature,
3192 as discussed above; handle here any cases we didn't catch then,
3193 such as X(X<T>). */
3196 }
3197 }
3200 /* Aha, this is a conversion function. */
3203 else
3208 /* This situation can occur if a member template of a template
3209 class is specialized. Then, instantiate_template might return
3210 an instantiation of the specialization, in which case the
3211 DECL_TI_TEMPLATE field will point at the original
3212 specialization. For example:
3214 template <class T> struct S { template <class U> void f(U);
3215 template <> void f(int) {}; };
3216 S<double> sd;
3217 sd.f(3);
3219 Here, TMPL will be template <class U> S<double>::f(U).
3220 And, instantiate template will give us the specialization
3221 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3222 for this will point at template <class T> template <> S<T>::f(int),
3223 so that we can find the definition. For the purposes of
3224 overload resolution, however, we want the original TMPL. */
3226 else
3231 fail:
3234 }
3243 {
3244 return
3249 }
3251 /* Create an overload candidate for the conversion function template TMPL,
3252 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3253 pointer-to-function which will in turn be called with the argument list
3254 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3255 passed on to implicit_conversion. */
3259 tree obj,
3263 {
3264 /* Making this work broke PR 71117, so until the committee resolves core
3265 issue 2189, let's disable this candidate if there are any viable call
3266 operators. */
3270 return
3274 complain);
3275 }
3277 /* The CANDS are the set of candidates that were considered for
3278 overload resolution. Return the set of viable candidates, or CANDS
3279 if none are viable. If any of the candidates were viable, set
3280 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3281 considered viable only if it is strictly viable. */
3287 {
3293 /* Be strict inside templates, since build_over_call won't actually
3294 do the conversions to get pedwarns. */
3304 {
3308 {
3309 /* Be strict in the presence of a viable candidate. Also if
3310 there are template candidates, so that we get deduction errors
3311 for them instead of silently preferring a bad conversion. */
3314 {
3315 /* Put any spliced near matches back onto the main list so
3316 that we see them if there is no strict match. */
3322 }
3323 }
3326 {
3334 }
3335 else
3337 }
3340 }
3342 static bool
3344 {
3349 }
3351 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3352 words, it is about to become the "this" pointer for a member
3353 function call. Take the address of the object. */
3355 static tree
3357 {
3358 /* In a template, we are only concerned about the type of the
3359 expression, so we can take a shortcut. */
3364 }
3366 /* Returns true iff functions are equivalent. Equivalent functions are
3367 not '==' only if one is a function-local extern function or if
3368 both are extern "C". */
3372 {
3381 }
3383 /* Print information about a candidate being rejected due to INFO. */
3385 static void
3387 {
3392 {
3393 /* Conversion of implicit `this' argument failed. */
3395 /* A bad conversion for 'this' must be discarding cv-quals. */
3398 from);
3399 else
3403 }
3405 {
3410 tf_warning_or_error);
3411 }
3413 /* Conversion of conversion function return value failed. */
3416 else
3419 }
3421 /* Print information about a candidate with WANT parameters and we found
3422 HAVE. */
3424 static void
3426 {
3431 }
3433 /* Print information about one overload candidate CANDIDATE. MSGSTR
3434 is the text to print before the candidate itself.
3436 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3437 to have been run through gettext by the caller. This wart makes
3438 life simpler in print_z_candidates and for the translators. */
3440 static void
3443 {
3453 {
3464 else
3467 }
3474 else
3477 {
3480 }
3481 /* Give the user some information about why this candidate failed. */
3483 {
3487 {
3500 "cannot be converted to %qT with a qualification "
3506 "conversion function specialization to %qT is not an "
3511 /* We use template_unification_error_rejection if unification caused
3512 actual non-SFINAE errors, in which case we don't need to repeat
3513 them here. */
3515 {
3519 }
3520 /* Re-run template unification with diagnostics. */
3524 (make_tree_vec
3535 " a constructor taking a single argument of its own "
3539 {
3543 }
3547 "initialization from an expression of the same or derived "
3552 /* This candidate didn't have any issues or we failed to
3553 handle a particular code. Either way... */
3555 }
3556 }
3557 }
3559 static void
3561 {
3568 /* Remove non-viable deleted candidates. */
3571 {
3576 else
3578 }
3579 /* ...if there are any non-deleted ones. */
3583 /* There may be duplicates in the set of candidates. We put off
3584 checking this condition as long as possible, since we have no way
3585 to eliminate duplicates from a set of functions in less than n^2
3586 time. Now we are about to emit an error message, so it is more
3587 permissible to go slowly. */
3589 {
3591 /* Skip builtin candidates and conversion functions. */
3596 {
3600 else
3602 }
3603 }
3607 }
3609 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3610 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3611 the result of the conversion function to convert it to the final
3612 desired type. Merge the two sequences into a single sequence,
3613 and return the merged sequence. */
3617 {
3623 /* Find the end of the second conversion sequence. */
3625 {
3626 /* The entire sequence is a user-conversion sequence. */
3630 }
3632 /* Replace the identity conversion with the user conversion
3633 sequence. */
3637 }
3639 /* Handle overload resolution for initializing an object of class type from
3640 an initializer list. First we look for a suitable constructor that
3641 takes a std::initializer_list; if we don't find one, we then look for a
3642 non-list constructor.
3644 Parameters are as for add_candidates, except that the arguments are in
3645 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3646 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3648 static void
3655 tsubst_flags_t complain)
3656 {
3659 /* We're looking for a ctor for list-initialization. */
3661 /* And we don't allow narrowing conversions. We also use this flag to
3662 avoid the copy constructor call for copy-list-initialization. */
3668 /* Always use the default constructor if the list is empty (DR 990). */
3671 ;
3672 /* If the class has a list ctor, try passing the list as a single
3673 argument first, but only consider list ctors. */
3675 {
3682 }
3684 /* Expand the CONSTRUCTOR into a new argument vec. */
3692 /* We aren't looking for list-ctors anymore. */
3694 /* We allow more user-defined conversions within an init-list. */
3700 }
3702 /* Returns the best overload candidate to perform the requested
3703 conversion. This function is used for three the overloading situations
3704 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3705 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3706 per [dcl.init.ref], so we ignore temporary bindings. */
3710 tsubst_flags_t complain)
3711 {
3713 tree fromtype;
3727 /* We represent conversion within a hierarchy using RVALUE_CONV and
3728 BASE_CONV, as specified by [over.best.ics]; these become plain
3729 constructor calls, as specified in [dcl.init]. */
3734 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3735 creating a garbage BASELINK; constructors can't be inherited. */
3738 /* FIXME P0135 doesn't say what to do in C++17 about list-initialization from
3739 a single element. For now, let's handle constructors as before and also
3740 consider conversion operators from the element. */
3747 {
3752 {
3753 /* [class.conv.fct] A conversion function is never used to
3754 convert a (possibly cv-qualified) object to the (possibly
3755 cv-qualified) same object type (or a reference to it), to a
3756 (possibly cv-qualified) base class of that type (or a
3757 reference to it)... */
3758 }
3759 else
3761 }
3768 /* It's OK to bind a temporary for converting constructor arguments, but
3769 not in converting the return value of a conversion operator. */
3775 {
3780 /* We should never try to call the abstract or base constructor
3781 from here. */
3787 {
3788 /* List-initialization. */
3792 }
3793 else
3794 {
3798 }
3801 {
3804 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3805 set, then this is copy-initialization. In that case, "The
3806 result of the call is then used to direct-initialize the
3807 object that is the destination of the copy-initialization."
3808 [dcl.init]
3810 We represent this in the conversion sequence with an
3811 rvalue conversion, which means a constructor call. */
3814 cand->second_conv
3816 }
3817 }
3820 {
3822 /* FIXME see above about C++17. */
3824 else
3826 }
3829 {
3833 /* If we are called to convert to a reference type, we are trying to
3834 find a direct binding, so don't even consider temporaries. If
3835 we don't find a direct binding, the caller will try again to
3836 look for a temporary binding. */
3847 {
3849 conversion *ics
3851 rettype,
3854 complain);
3856 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3857 copy-initialization. In that case, "The result of the
3858 call is then used to direct-initialize the object that is
3859 the destination of the copy-initialization." [dcl.init]
3861 We represent this in the conversion sequence with an
3862 rvalue conversion, which means a constructor call. But
3863 don't add a second rvalue conversion if there's already
3864 one there. Which there really shouldn't be, but it's
3865 harmless since we'd add it here anyway. */
3873 {
3877 }
3880 {
3881 /* 13.3.1.5: For direct-initialization, those explicit
3882 conversion functions that are not hidden within S and
3883 yield type T or a type that can be converted to type T
3884 with a qualification conversion (4.4) are also candidate
3885 functions. */
3886 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3887 I've raised this issue with the committee. --jason 9/2011 */
3890 }
3892 {
3894 cand->reason
3897 }
3900 {
3901 /* 13.3.3.1.2: If the user-defined conversion is specified by
3902 a specialization of a conversion function template, the
3903 second standard conversion sequence shall have exact match
3904 rank. */
3907 }
3908 }
3909 }
3913 {
3917 }
3921 {
3923 {
3927 }
3934 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3935 ambiguous conversion is no worse than another user-defined
3936 conversion. */
3939 }
3941 tree convtype;
3945 /* DR 5: [in the first step of copy-initialization]...if the function
3946 is a constructor, the call initializes a temporary of the
3947 cv-unqualified version of the destination type. */
3949 else
3951 /* Build the user conversion sequence. */
3952 conv = build_conv
3954 convtype,
3960 /* Remember that this was a list-initialization. */
3964 /* Combine it with the second conversion sequence. */
3969 }
3971 /* Wrapper for above. */
3973 tree
3975 tsubst_flags_t complain)
3976 {
3978 tree ret;
3984 {
3987 else
3988 {
3991 }
3992 }
3993 else
3998 }
4000 /* Subroutine of convert_nontype_argument.
4002 EXPR is an expression used in a context that requires a converted
4003 constant-expression, such as a template non-type parameter. Do any
4004 necessary conversions (that are permitted for converted
4005 constant-expressions) to convert it to the desired type.
4007 If conversion is successful, returns the converted expression;
4008 otherwise, returns error_mark_node. */
4010 tree
4012 {
4015 tree t;
4021 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4028 /* A converted constant expression of type T is an expression, implicitly
4029 converted to type T, where the converted expression is a constant
4030 expression and the implicit conversion sequence contains only
4032 * user-defined conversions,
4033 * lvalue-to-rvalue conversions (7.1),
4034 * array-to-pointer conversions (7.2),
4035 * function-to-pointer conversions (7.3),
4036 * qualification conversions (7.5),
4037 * integral promotions (7.6),
4038 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4039 * null pointer conversions (7.11) from std::nullptr_t,
4040 * null member pointer conversions (7.12) from std::nullptr_t, and
4041 * function pointer conversions (7.13),
4043 and where the reference binding (if any) binds directly. */
4048 {
4050 {
4051 /* A conversion function is OK. If it isn't constexpr, we'll
4052 complain later that the argument isn't constant. */
4054 /* The lvalue-to-rvalue conversion is OK. */
4056 /* Array-to-pointer and function-to-pointer. */
4058 /* Function pointer conversions. */
4060 /* Qualification conversions. */
4066 {
4072 }
4082 /* Integral promotion or conversion. */
4085 /* Conversion from nullptr to pointer or pointer-to-member. */
4091 /* fall through. */
4096 }
4097 }
4099 /* Avoid confusing convert_nontype_argument by introducing
4100 a redundant conversion to the same reference type. */
4103 {
4107 }
4111 else
4114 /* Free all the conversions we allocated. */
4118 }
4120 /* Do any initial processing on the arguments to a function call. */
4124 {
4126 tree arg;
4129 {
4133 {
4137 }
4140 }
4142 }
4144 /* Perform overload resolution on FN, which is called with the ARGS.
4146 Return the candidate function selected by overload resolution, or
4147 NULL if the event that overload resolution failed. In the case
4148 that overload resolution fails, *CANDIDATES will be the set of
4149 candidates considered, and ANY_VIABLE_P will be set to true or
4150 false to indicate whether or not any of the candidates were
4151 viable.
4153 The ARGS should already have gone through RESOLVE_ARGS before this
4154 function is called. */
4161 {
4163 tree explicit_targs;
4174 /* Check FN. */
4181 {
4185 }
4187 /* Add the various candidate functions. */
4192 LOOKUP_NORMAL,
4198 else
4203 }
4205 /* Print an error message about being unable to build a call to FN with
4206 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4207 be located; CANDIDATES is a possibly empty list of such
4208 functions. */
4210 static void
4213 {
4216 {
4219 }
4228 else
4233 }
4235 /* Return an expression for a call to FN (a namespace-scope function,
4236 or a static member function) with the ARGS. This may change
4237 ARGS. */
4239 tree
4241 tsubst_flags_t complain)
4242 {
4246 tree result;
4249 {
4253 }
4258 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4262 complain);
4265 {
4267 {
4268 // If there is a single (non-viable) function candidate,
4269 // let the error be diagnosed by cp_build_function_call_vec.
4274 // Otherwise, emit notes for non-viable candidates.
4276 }
4278 }
4279 else
4280 {
4282 /* If fn is template_id_expr, the call has explicit template arguments
4283 (e.g. func<int>(5)), communicate this info to build_over_call
4284 through flags so that later we can use it to decide whether to warn
4285 about peculiar null pointer conversion. */
4287 {
4288 /* If overload resolution selects a specialization of a
4289 function concept for non-dependent template arguments,
4290 the expression is true if the constraints are satisfied
4291 and false otherwise.
4293 NOTE: This is an extension of Concepts Lite TS that
4294 allows constraints to be used in expressions. */
4296 {
4302 }
4305 }
4308 }
4310 /* Free all the conversions we allocated. */
4314 }
4316 /* Build a call to a global operator new. FNNAME is the name of the
4317 operator (either "operator new" or "operator new[]") and ARGS are
4318 the arguments provided. This may change ARGS. *SIZE points to the
4319 total number of bytes required by the allocation, and is updated if
4320 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4321 be used. If this function determines that no cookie should be
4322 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4323 is not NULL_TREE, it is evaluated before calculating the final
4324 array size, and if it fails, the array size is replaced with
4325 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4326 is non-NULL, it will be set, upon return, to the allocation
4327 function called. */
4329 tree
4334 {
4336 tree fns;
4343 /* Set to (size_t)-1 if the size check fails. */
4345 {
4351 }
4357 /* Based on:
4359 [expr.new]
4361 If this lookup fails to find the name, or if the allocated type
4362 is not a class type, the allocation function's name is looked
4363 up in the global scope.
4365 we disregard block-scope declarations of "operator new". */
4370 {
4377 /* If no aligned allocation function matches, try again without the
4378 alignment. */
4379 }
4381 /* Figure out what function is being called. */
4384 complain);
4386 /* If no suitable function could be found, issue an error message
4387 and give up. */
4389 {
4393 }
4395 /* If a cookie is required, add some extra space. Whether
4396 or not a cookie is required cannot be determined until
4397 after we know which function was called. */
4399 {
4401 tree arg_types;
4404 /* Skip the size_t parameter. */
4406 /* Check the remaining parameters (if any). */
4410 ptr_type_node))
4412 /* If we need a cookie, adjust the number of bytes allocated. */
4414 {
4415 /* Update the total size. */
4418 {
4419 /* Set to (size_t)-1 if the size check fails. */
4423 }
4424 /* Update the argument list to reflect the adjusted size. */
4426 }
4427 else
4429 }
4431 /* Tell our caller which function we decided to call. */
4435 /* Build the CALL_EXPR. */
4437 }
4439 /* Build a new call to operator(). This may change ARGS. */
4441 static tree
4443 {
4460 {
4462 /* It's no good looking for an overloaded operator() on a
4463 pointer-to-member-function. */
4467 }
4470 {
4474 }
4475 else
4479 {
4483 }
4485 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4489 {
4497 }
4502 {
4510 {
4517 add_template_conv_candidate
4521 else
4525 }
4526 }
4528 /* Be strict here because if we choose a bad conversion candidate, the
4529 errors we get won't mention the call context. */
4532 {
4534 {
4538 }
4540 }
4541 else
4542 {
4545 {
4547 {
4551 }
4553 }
4558 else
4559 {
4563 else
4564 {
4567 }
4570 }
4571 }
4573 /* Free all the conversions we allocated. */
4577 }
4579 /* Wrapper for above. */
4581 tree
4583 {
4584 tree ret;
4589 }
4591 /* Called by op_error to prepare format strings suitable for the error
4592 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4593 and a suffix (controlled by NTYPES). */
4597 {
4607 else
4611 }
4613 static void
4616 {
4621 {
4627 else
4639 else
4649 else
4660 else
4670 else
4675 else
4679 else
4684 }
4685 }
4687 /* Return the implicit conversion sequence that could be used to
4688 convert E1 to E2 in [expr.cond]. */
4692 {
4698 /* [expr.cond]
4700 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4701 implicitly converted (clause _conv_) to the type "lvalue reference to
4702 T2", subject to the constraint that in the conversion the
4703 reference must bind directly (_dcl.init.ref_) to an lvalue.
4705 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4706 implicitly converted to the type "rvalue reference to T2", subject to
4707 the constraint that the reference must bind directly. */
4709 {
4712 t1,
4713 e1,
4715 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4717 complain);
4720 }
4722 /* If E2 is a prvalue or if neither of the conversions above can be done
4723 and at least one of the operands has (possibly cv-qualified) class
4724 type: */
4728 /* [expr.cond]
4730 If E1 and E2 have class type, and the underlying class types are
4731 the same or one is a base class of the other: E1 can be converted
4732 to match E2 if the class of T2 is the same type as, or a base
4733 class of, the class of T1, and the cv-qualification of T2 is the
4734 same cv-qualification as, or a greater cv-qualification than, the
4735 cv-qualification of T1. If the conversion is applied, E1 is
4736 changed to an rvalue of type T2 that still refers to the original
4737 source class object (or the appropriate subobject thereof). */
4740 {
4742 {
4747 else
4750 }
4751 else
4753 }
4754 else
4755 /* [expr.cond]
4757 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4758 converted to the type that expression E2 would have if E2 were
4759 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4762 }
4764 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4765 arguments to the conditional expression. */
4767 static tree
4769 tsubst_flags_t complain)
4770 {
4771 tree arg2_type;
4772 tree arg3_type;
4781 /* As a G++ extension, the second argument to the conditional can be
4782 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4783 c'.) If the second operand is omitted, make sure it is
4784 calculated only once. */
4786 {
4794 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4797 else
4799 }
4801 /* If something has already gone wrong, just pass that fact up the
4802 tree. */
4812 {
4815 /* If arg1 is another cond_expr choosing between -1 and 0,
4816 then we can use its comparison. It may help to avoid
4817 additional comparison, produce more accurate diagnostics
4818 and enables folding. */
4828 /* force_rvalue can return error_mark on valid arguments. */
4839 {
4840 /* Rely on the error messages of the scalar version. */
4849 {
4857 }
4861 /* We could pass complain & tf_warning to unsafe_conversion_p,
4862 but the warnings (like Wsign-conversion) have already been
4863 given by the scalar build_conditional_expr_1. We still check
4864 unsafe_conversion_p to forbid truncating long long -> float. */
4866 {
4871 }
4873 {
4878 }
4888 }
4891 {
4897 {
4901 {
4907 }
4909 {
4915 }
4918 }
4919 }
4925 {
4928 "incompatible vector types in conditional expression: "
4932 }
4935 {
4938 }
4940 }
4942 /* [expr.cond]
4944 The first expression is implicitly converted to bool (clause
4945 _conv_). */
4947 LOOKUP_NORMAL);
4951 /* [expr.cond]
4953 If either the second or the third operand has type (possibly
4954 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4955 array-to-pointer (_conv.array_), and function-to-pointer
4956 (_conv.func_) standard conversions are performed on the second
4957 and third operands. */
4961 {
4962 /* Do the conversions. We don't these for `void' type arguments
4963 since it can't have any effect and since decay_conversion
4964 does not handle that case gracefully. */
4972 /* [expr.cond]
4974 One of the following shall hold:
4976 --The second or the third operand (but not both) is a
4977 throw-expression (_except.throw_); the result is of the
4978 type of the other and is an rvalue.
4980 --Both the second and the third operands have type void; the
4981 result is of type void and is an rvalue.
4983 We must avoid calling force_rvalue for expressions of type
4984 "void" because it will complain that their value is being
4985 used. */
4988 {
4990 {
4994 }
4997 }
5000 {
5002 {
5006 }
5009 }
5012 else
5013 {
5015 {
5018 "second operand to the conditional operator "
5019 "is of type %<void%>, but the third operand is "
5021 else
5023 "third operand to the conditional operator "
5024 "is of type %<void%>, but the second operand is "
5026 }
5028 }
5032 }
5033 /* [expr.cond]
5035 Otherwise, if the second and third operand have different types,
5036 and either has (possibly cv-qualified) class type, or if both are
5037 glvalues of the same value category and the same type except for
5038 cv-qualification, an attempt is made to convert each of those operands
5039 to the type of the other. */
5043 arg3_type)
5046 {
5051 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5057 /* [expr.cond]
5059 If both can be converted, or one can be converted but the
5060 conversion is ambiguous, the program is ill-formed. If
5061 neither can be converted, the operands are left unchanged and
5062 further checking is performed as described below. If exactly
5063 one conversion is possible, that conversion is applied to the
5064 chosen operand and the converted operand is used in place of
5065 the original operand for the remainder of this section. */
5070 {
5072 {
5079 else
5081 }
5083 }
5085 {
5089 /* Even if CONV2 is a valid conversion, the result of the
5090 conversion may be invalid. For example, if ARG3 has type
5091 "volatile X", and X does not have a copy constructor
5092 accepting a "volatile X&", then even if ARG2 can be
5093 converted to X, the conversion will fail. */
5097 }
5099 {
5106 }
5108 /* Free all the conversions we allocated. */
5114 /* If, after the conversion, both operands have class type,
5115 treat the cv-qualification of both operands as if it were the
5116 union of the cv-qualification of the operands.
5118 The standard is not clear about what to do in this
5119 circumstance. For example, if the first operand has type
5120 "const X" and the second operand has a user-defined
5121 conversion to "volatile X", what is the type of the second
5122 operand after this step? Making it be "const X" (matching
5123 the first operand) seems wrong, as that discards the
5124 qualification without actually performing a copy. Leaving it
5125 as "volatile X" seems wrong as that will result in the
5126 conditional expression failing altogether, even though,
5127 according to this step, the one operand could be converted to
5128 the type of the other. */
5136 }
5138 /* [expr.cond]
5140 If the second and third operands are glvalues of the same value
5141 category and have the same type, the result is of that type and
5142 value category. */
5146 {
5151 }
5153 /* [expr.cond]
5155 Otherwise, the result is an rvalue. If the second and third
5156 operand do not have the same type, and either has (possibly
5157 cv-qualified) class type, overload resolution is used to
5158 determine the conversions (if any) to be applied to the operands
5159 (_over.match.oper_, _over.built_). */
5163 {
5168 /* Rearrange the arguments so that add_builtin_candidate only has
5169 to know about two args. In build_builtin_candidate, the
5170 arguments are unscrambled. */
5175 COND_EXPR,
5176 NOP_EXPR,
5178 args,
5181 /* [expr.cond]
5183 If the overload resolution fails, the program is
5184 ill-formed. */
5187 {
5192 }
5195 {
5197 {
5200 }
5202 }
5204 /* [expr.cond]
5206 Otherwise, the conversions thus determined are applied, and
5207 the converted operands are used in place of the original
5208 operands for the remainder of this section. */
5217 }
5219 /* [expr.cond]
5221 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5222 and function-to-pointer (_conv.func_) standard conversions are
5223 performed on the second and third operands.
5225 We need to force the lvalue-to-rvalue conversion here for class types,
5226 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5227 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5228 regions. */
5241 /* [expr.cond]
5243 After those conversions, one of the following shall hold:
5245 --The second and third operands have the same type; the result is of
5246 that type. */
5249 /* [expr.cond]
5251 --The second and third operands have arithmetic or enumeration
5252 type; the usual arithmetic conversions are performed to bring
5253 them to a common type, and the result is of that type. */
5258 {
5259 /* In this case, there is always a common type. */
5261 arg3_type);
5264 "implicit conversion from %qH to %qI to "
5266 loc);
5270 {
5274 /* Two enumerators from the same enumeration can have different
5280 }
5287 {
5291 }
5295 }
5296 /* [expr.cond]
5298 --The second and third operands have pointer type, or one has
5299 pointer type and the other is a null pointer constant; pointer
5300 conversions (_conv.ptr_) and qualification conversions
5301 (_conv.qual_) are performed to bring them to their composite
5302 pointer type (_expr.rel_). The result is of the composite
5303 pointer type.
5305 --The second and third operands have pointer to member type, or
5306 one has pointer to member type and the other is a null pointer
5307 constant; pointer to member conversions (_conv.mem_) and
5308 qualification conversions (_conv.qual_) are performed to bring
5309 them to a common type, whose cv-qualification shall match the
5310 cv-qualification of either the second or the third operand.
5311 The result is of the common type. */
5319 {
5322 complain);
5327 }
5330 {
5335 }
5340 valid_operands:
5343 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5344 warn here, because the COND_EXPR will be turned into ARG2. */
5350 /* We can't use result_type below, as fold might have returned a
5351 throw_expr. */
5354 {
5355 /* Expand both sides into the same slot, hopefully the target of
5356 the ?: expression. We used to check for TARGET_EXPRs here,
5357 but now we sometimes wrap them in NOP_EXPRs so the test would
5358 fail. */
5361 /* If this expression is an rvalue, but might be mistaken for an
5362 lvalue, we must add a NON_LVALUE_EXPR. */
5364 }
5365 else
5369 }
5371 /* Wrapper for above. */
5373 tree
5375 tsubst_flags_t complain)
5376 {
5377 tree ret;
5382 }
5384 /* OPERAND is an operand to an expression. Perform necessary steps
5385 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5386 returned. */
5388 static tree
5390 {
5392 {
5395 /* Make sure the template type is instantiated now. */
5397 }
5400 }
5402 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5403 OVERLOAD) to the CANDIDATES, returning an updated list of
5404 CANDIDATES. The ARGS are the arguments provided to the call;
5405 if FIRST_ARG is non-null it is the implicit object argument,
5406 otherwise the first element of ARGS is used if needed. The
5407 EXPLICIT_TARGS are explicit template arguments provided.
5408 TEMPLATE_ONLY is true if only template functions should be
5409 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5410 add_function_candidate. */
5412 static void
5414 tree return_type,
5419 tsubst_flags_t complain)
5420 {
5421 tree ctype;
5425 unification_kind_t strict;
5430 /* Precalculate special handling of constructors and conversion ops. */
5433 {
5437 /* We're doing return_type(x). */
5439 else
5440 /* We're doing x.operator return_type(). */
5442 /* [over.match.funcs] For conversion functions, the function
5443 is considered to be a member of the class of the implicit
5444 object argument for the purpose of defining the type of
5445 the implicit object parameter. */
5447 }
5448 else
5449 {
5451 {
5453 /* For list-initialization we consider explicit constructors
5454 and complain if one is chosen. */
5455 check_converting
5458 }
5461 }
5465 else
5466 /* Delay creating the implicit this parameter until it is needed. */
5470 {
5482 {
5483 /* Figure out where the object arg comes from. If this
5484 function is a non-static member and we didn't get an
5485 implicit object argument, move it out of args. */
5487 {
5489 tree arg;
5496 }
5500 }
5504 fn,
5505 ctype,
5506 explicit_targs,
5507 fn_first_arg,
5508 fn_args,
5509 return_type,
5510 access_path,
5511 conversion_path,
5512 flags,
5513 strict,
5514 complain);
5517 fn,
5518 ctype,
5519 fn_first_arg,
5520 fn_args,
5521 access_path,
5522 conversion_path,
5523 flags,
5524 complain);
5525 }
5526 }
5528 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5529 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5531 static int
5533 {
5535 {
5536 // 5. b @= a
5540 // 6. a[b]
5544 // 1. a.b
5545 // Not overloadable (yet).
5546 // 2. a->b
5547 // Only one argument.
5548 // 3. a->*b
5550 // 7. a << b
5552 // 8. a >> b
5558 }
5559 }
5561 static tree
5564 {
5585 {
5588 }
5595 {
5600 /* Use build_op_new_call and build_op_delete_call instead. */
5604 /* Use build_op_call instead. */
5611 /* These are saved for the sake of warn_logical_operator. */
5621 /* These are saved for the sake of maybe_warn_bool_compare. */
5626 /* =, ->, [], () must be non-static member functions. */
5630 /* FALLTHRU */
5638 }
5644 /* Use build_conditional_expr instead. */
5660 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5663 /* Add namespace-scope operators to the list of functions to
5664 consider. */
5666 {
5672 }
5678 /* Add class-member operators to the candidate set. */
5680 {
5681 tree fns;
5685 {
5688 }
5696 }
5697 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5698 only non-member functions that have type T1 or reference to
5699 cv-qualified-opt T1 for the first argument, if the first argument
5700 has an enumeration type, or T2 or reference to cv-qualified-opt
5701 T2 for the second argument, if the second argument has an
5702 enumeration type. Filter out those that don't match. */
5704 {
5708 {
5718 {
5724 && (same_type_ignoring_top_level_qualifiers_p
5729 }
5731 /* No argument has an appropriate type, so remove this
5732 candidate function from the list. */
5734 {
5737 }
5738 }
5739 }
5745 {
5748 /* For these, the built-in candidates set is empty
5749 [over.match.oper]/3. We don't want non-strict matches
5750 because exact matches are always possible with built-in
5751 operators. The built-in candidate set for COMPONENT_REF
5752 would be empty too, but since there are no such built-in
5753 operators, we accept non-strict matches for them. */
5760 }
5764 {
5766 {
5769 /* Don't try anything fancy if we're not allowed to produce
5770 errors. */
5774 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5775 distinguish between prefix and postfix ++ and
5776 operator++() was used for both, so we allow this with
5777 -fpermissive. */
5778 else
5779 {
5785 }
5792 else
5798 /* The caller will deal with these. */
5808 {
5809 /* If one of the arguments of the operator represents
5810 an invalid use of member function pointer, try to report
5811 a meaningful error ... */
5816 else
5817 {
5818 /* ... Otherwise, report the more generic
5819 "no matching operator found" error */
5822 }
5823 }
5826 }
5827 }
5828 else
5829 {
5832 {
5834 {
5837 }
5839 }
5841 {
5847 else
5853 {
5858 /* This prevents build_new_function_call from discarding this
5859 function during instantiation of the enclosing template. */
5862 /* Specify evaluation order as per P0145R2. */
5865 {
5876 }
5877 }
5878 }
5879 else
5880 {
5881 /* Give any warnings we noticed during overload resolution. */
5883 {
5887 }
5889 /* Check for comparison of different enum types. */
5891 {
5903 {
5907 }
5911 }
5913 /* We need to strip any leading REF_BIND so that bitfields
5914 don't cause errors. This should not remove any important
5915 conversions, because builtins don't apply to class
5916 objects directly. */
5923 {
5927 else
5930 /* We need to call warn_logical_operator before
5931 converting arg2 to a boolean_type, but after
5932 decaying an enumerator to its value. */
5939 }
5941 {
5946 }
5948 }
5949 }
5951 user_defined_result_ready:
5953 /* Free all the conversions we allocated. */
5959 builtin:
5961 {
5976 /* Fall through. */
5989 /* Fall through. */
6022 complain),
6025 /* The caller will deal with these. */
6033 }
6035 }
6037 /* Wrapper for above. */
6039 tree
6043 {
6044 tree ret;
6050 }
6052 /* CALL was returned by some call-building function; extract the actual
6053 CALL_EXPR from any bits that have been tacked on, e.g. by
6054 convert_from_reference. */
6056 tree
6058 {
6069 }
6071 /* Returns true if FN has two parameters, of which the second has type
6072 size_t. */
6074 static bool
6076 {
6088 }
6090 /* True if T, an allocation function, has std::align_val_t as its second
6091 argument. */
6093 bool
6095 {
6101 }
6103 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6104 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6105 std::align_val_t. */
6107 static bool
6109 {
6113 /* A template instance is never a usual deallocation function,
6114 regardless of its signature. */
6130 }
6132 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6133 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6135 bool
6137 {
6138 /* A template instance is never a usual deallocation function,
6139 regardless of its signature. */
6144 /* If a class T has a member deallocation function named operator delete
6145 with exactly one parameter, then that function is a usual
6146 (non-placement) deallocation function. If class T does not declare
6147 such an operator delete but does declare a member deallocation
6148 function named operator delete with exactly two parameters, the second
6149 of which has type std::size_t (18.2), then this function is a usual
6150 deallocation function. */
6162 }
6164 /* Build a call to operator delete. This has to be handled very specially,
6165 because the restrictions on what signatures match are different from all
6166 other call instances. For a normal delete, only a delete taking (void *)
6167 or (void *, size_t) is accepted. For a placement delete, only an exact
6168 match with the placement new is accepted.
6170 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6171 ADDR is the pointer to be deleted.
6172 SIZE is the size of the memory block to be deleted.
6173 GLOBAL_P is true if the delete-expression should not consider
6174 class-specific delete operators.
6175 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6177 If this call to "operator delete" is being generated as part to
6178 deallocate memory allocated via a new-expression (as per [expr.new]
6179 which requires that if the initialization throws an exception then
6180 we call a deallocation function), then ALLOC_FN is the allocation
6181 function. */
6183 tree
6187 {
6201 /* In [class.free]
6203 If the result of the lookup is ambiguous or inaccessible, or if
6204 the lookup selects a placement deallocation function, the
6205 program is ill-formed.
6207 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6208 {
6212 }
6213 else
6219 /* Strip const and volatile from addr. */
6223 {
6224 /* "A declaration of a placement deallocation function matches the
6225 declaration of a placement allocation function if it has the same
6226 number of parameters and, after parameter transformations (8.3.5),
6227 all parameter types except the first are identical."
6229 So we build up the function type we want and ask instantiate_type
6230 to get it for us. */
6241 /* "If the lookup finds the two-parameter form of a usual deallocation
6242 function (3.7.4.2) and that function, considered as a placement
6243 deallocation function, would have been selected as a match for the
6244 allocation function, the program is ill-formed." */
6246 {
6254 /* But if the class has an operator delete (void *), then that is
6255 the usual deallocation function, so we shouldn't complain
6256 about using the operator delete (void *, size_t). */
6260 {
6265 }
6266 /* Before C++14 a two-parameter global deallocation function is
6267 always a placement deallocation function, but warn if
6268 -Wc++14-compat. */
6270 {
6275 }
6278 {
6280 {
6281 /* Only mention C++14 for namespace-scope delete. */
6284 else
6286 "%qD is a usual (non-placement) deallocation "
6288 }
6289 }
6290 else
6292 ok:;
6293 }
6294 }
6295 else
6296 /* "Any non-placement deallocation function matches a non-placement
6297 allocation function. If the lookup finds a single matching
6298 deallocation function, that function will be called; otherwise, no
6299 deallocation function will be called." */
6301 {
6304 {
6306 {
6309 }
6311 /* -- If the type has new-extended alignment, a function with a
6312 parameter of type std::align_val_t is preferred; otherwise a
6313 function without such a parameter is preferred. If exactly one
6314 preferred function is found, that function is selected and the
6315 selection process terminates. If more than one preferred
6316 function is found, all non-preferred functions are eliminated
6317 from further consideration. */
6319 {
6325 {
6329 }
6330 }
6332 /* -- If the deallocation functions have class scope, the one
6333 without a parameter of type std::size_t is selected. */
6338 /* -- If the type is complete and if, for the second alternative
6339 (delete array) only, the operand is a pointer to a class type
6340 with a non-trivial destructor or a (possibly multi-dimensional)
6341 array thereof, the function with a parameter of type std::size_t
6342 is selected.
6344 -- Otherwise, it is unspecified whether a deallocation function
6345 with a parameter of type std::size_t is selected. */
6346 else
6347 {
6351 /* We need a cookie to determine the array size. */
6353 }
6359 }
6360 }
6362 /* If we have a matching function, call it. */
6364 {
6367 /* If the FN is a member function, make sure that it is
6368 accessible. */
6371 complain);
6373 /* Core issue 901: It's ok to new a type with deleted delete. */
6378 {
6379 /* The placement args might not be suitable for overload
6380 resolution at this point, so build the call directly. */
6390 }
6391 else
6392 {
6393 tree ret;
6399 {
6402 }
6406 }
6407 }
6409 /* [expr.new]
6411 If no unambiguous matching deallocation function can be found,
6412 propagating the exception does not cause the object's memory to
6413 be freed. */
6415 {
6419 alloc_fn);
6421 }
6427 }
6429 /* If the current scope isn't allowed to access DECL along
6430 BASETYPE_PATH, give an error. The most derived class in
6431 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6432 the declaration to use in the error diagnostic. */
6434 bool
6437 {
6442 {
6443 /* 7.3.3/18: The additional constructors are accessible if they would be
6444 accessible when used to construct an object of the corresponding base
6445 class. */
6449 }
6452 {
6454 {
6458 {
6464 }
6466 {
6472 }
6473 else
6474 {
6479 }
6480 }
6482 }
6485 }
6487 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6488 bitwise or of LOOKUP_* values. If any errors are warnings are
6489 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6490 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6491 to NULL. */
6493 static tree
6496 {
6502 /* If the source is a packed field, calling the copy constructor will require
6503 binding the field to the reference parameter to the copy constructor, and
6504 we'll end up with an infinite loop. If we can use a bitwise copy, then
6505 do that now. */
6521 }
6523 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6524 EXPR is implicitly converted to type TOTYPE.
6525 FN and ARGNUM are used for diagnostics. */
6527 static void
6529 {
6530 /* Issue warnings about peculiar, but valid, uses of NULL. */
6533 {
6534 source_location loc =
6541 else
6544 }
6546 /* Issue warnings if "false" is converted to a NULL pointer */
6549 {
6552 "converting %<false%> to pointer type for argument %P "
6554 else
6557 }
6558 }
6560 /* We gave a diagnostic during a conversion. If this was in the second
6561 standard conversion sequence of a user-defined conversion sequence, say
6562 which user-defined conversion. */
6564 static void
6566 {
6570 {
6574 }
6575 }
6577 /* Locate the parameter with the given index within FNDECL.
6578 ARGNUM is zero based, -1 indicates the `this' argument of a method.
6579 Return the location of the FNDECL itself if there are problems. */
6581 static location_t
6583 {
6585 tree param;
6587 /* Locate param by index within DECL_ARGUMENTS (fndecl). */
6591 ;
6593 /* If something went wrong (e.g. if we have a builtin and thus no arguments),
6594 return the location of FNDECL. */
6599 }
6601 /* Perform the conversions in CONVS on the expression EXPR. FN and
6602 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6603 indicates the `this' argument of a method. INNER is nonzero when
6604 being called to continue a conversion chain. It is negative when a
6605 reference binding will be applied, positive otherwise. If
6606 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6607 conversions will be emitted if appropriate. If C_CAST_P is true,
6608 this conversion is coming from a C-style cast; in that case,
6609 conversions to inaccessible bases are permitted. */
6611 static tree
6615 {
6617 diagnostic_t diag_kind;
6633 {
6637 /* Give a helpful error if this is bad because of excess braces. */
6642 {
6648 }
6650 /* Give a helpful error if this is bad because a conversion to bool
6651 from std::nullptr_t requires direct-initialization. */
6659 {
6661 {
6664 totype);
6670 complain);
6674 complain);
6675 else
6681 }
6683 {
6687 complain);
6689 }
6694 complain);
6697 }
6706 }
6712 {
6714 {
6718 /* We chose the surrogate function from add_conv_candidate, now we
6719 actually need to build the conversion. */
6725 /* When converting from an init list we consider explicit
6726 constructors, but actually trying to call one is an error. */
6729 /* Unless this is for direct-list-initialization. */
6731 /* And in C++98 a default constructor can't be explicit. */
6733 {
6739 {
6745 }
6746 else
6749 }
6751 /* If we're initializing from {}, it's value-initialization. */
6755 {
6760 {
6763 }
6765 }
6769 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6770 any more UDCs. */
6772 complain);
6774 /* If this is a constructor or a function returning an aggr type,
6775 we need to build up a TARGET_EXPR. */
6777 {
6780 /* Remember that this was list-initialization. */
6783 }
6786 }
6789 {
6795 else
6797 }
6804 /* We leave bad_p off ck_ambig because overload resolution considers
6805 it valid, it just fails when we try to perform it. So we need to
6806 check complain here, too. */
6808 {
6809 /* Call build_user_type_conversion again for the error. */
6811 complain);
6815 }
6819 {
6820 /* Conversion to std::initializer_list<T>. */
6828 /* Convert all the elements. */
6830 {
6841 }
6842 /* Build up the array. */
6843 elttype = cp_build_qualified_type
6847 /* Take the address explicitly rather than via decay_conversion
6848 to avoid the error about taking the address of a temporary. */
6854 /* Build up the initializer_list object. */
6862 }
6866 {
6875 }
6878 complain);
6885 };
6889 c_cast_p,
6890 complain);
6895 {
6899 {
6901 {
6906 }
6908 }
6913 /* Don't introduce copies when passing arguments along to the inherited
6914 constructor. */
6916 && flag_new_inheriting_ctors
6920 /* Fall through. */
6923 {
6924 /* We are going to bind a reference directly to a base-class
6925 subobject of EXPR. */
6926 /* Build an expression for `*((base*) &expr)'. */
6930 }
6932 /* Copy-initialization where the cv-unqualified version of the source
6933 type is the same class as, or a derived class of, the class of the
6934 destination [is treated as direct-initialization]. [dcl.init] */
6937 /* This conversion is being done in the context of a user-defined
6938 conversion (i.e. the second step of copy-initialization), so
6939 don't allow any more. */
6941 else
6944 /* standard_conversion got LOOKUP_PREFER_RVALUE. */
6948 /* Copy-list-initialization doesn't actually involve a copy. */
6952 {
6957 }
6962 {
6966 {
6979 else
6986 }
6988 /* If necessary, create a temporary.
6990 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6991 that need temporaries, even when their types are reference
6992 compatible with the type of reference being bound, so the
6993 upcoming call to cp_build_addr_expr doesn't fail. */
6997 {
6998 /* Otherwise, a temporary of type "cv1 T1" is created and
6999 initialized from the initializer expression using the rules
7000 for a non-reference copy-initialization (8.5). */
7009 {
7010 /* If the reference is volatile or non-const, we
7011 cannot create a temporary. */
7018 else
7022 }
7023 /* If the source is a packed field, and we must use a copy
7024 constructor, then building the target expr will require
7025 binding the field to the reference parameter to the
7026 copy constructor, and we'll end up with an infinite
7027 loop. If we can use a bitwise copy, then we'll be
7028 OK. */
7032 {
7036 }
7038 {
7041 }
7043 }
7045 /* Take the address of the thing to which we will bind the
7046 reference. */
7051 /* Convert it to a pointer to the type referred to by the
7052 reference. This will adjust the pointer if a derived to
7053 base conversion is being performed. */
7056 /* Convert the pointer to the desired reference type. */
7058 }
7064 /* ??? Should the address of a transaction-safe pointer point to the TM
7065 clone, and this conversion look up the primary function? */
7069 /* Warn about deprecated conversion if appropriate. */
7085 }
7093 else
7097 }
7099 /* ARG is being passed to a varargs function. Perform any conversions
7100 required. Return the converted value. */
7102 tree
7104 {
7105 tree arg_type;
7108 /* [expr.call]
7110 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7111 standard conversions are performed. */
7114 /* [expr.call]
7116 If the argument has integral or enumeration type that is subject
7117 to the integral promotions (_conv.prom_), or a floating point
7118 type that is subject to the floating point promotion
7119 (_conv.fpprom_), the value of the argument is converted to the
7120 promoted type before the call. */
7125 {
7129 "implicit conversion from %qH to %qI when passing "
7133 }
7137 {
7139 {
7141 complain);
7151 }
7152 else
7154 }
7160 /* In a template (or ill-formed code), we can have an incomplete type
7161 even after require_complete_type_sfinae, in which case we don't know
7162 whether it has trivial copy or not. */
7165 {
7166 /* [expr.call] 5.2.2/7:
7167 Passing a potentially-evaluated argument of class type (Clause 9)
7168 with a non-trivial copy constructor or a non-trivial destructor
7169 with no corresponding parameter is conditionally-supported, with
7170 implementation-defined semantics.
7172 We support it as pass-by-invisible-reference, just like a normal
7173 value parameter.
7175 If the call appears in the context of a sizeof expression,
7176 it is not potentially-evaluated. */
7179 {
7183 "passing objects of non-trivially-copyable "
7185 arg_type);
7187 }
7188 /* Build up a real lvalue-to-rvalue conversion in case the
7189 copy constructor is trivial but not callable. */
7193 }
7196 }
7198 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7200 tree
7202 {
7204 {
7208 }
7218 {
7221 }
7225 {
7226 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7227 it as pass by invisible reference. */
7229 "receiving objects of non-trivially-copyable type %q#T "
7235 }
7239 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7240 know how to handle it. */
7243 }
7245 /* TYPE has been given to va_arg. Apply the default conversions which
7246 would have happened when passed via ellipsis. Return the promoted
7247 type, or the passed type if there is no change. */
7249 tree
7251 {
7252 tree promote;
7254 /* Perform the array-to-pointer and function-to-pointer
7255 conversions. */
7263 }
7265 /* ARG is a default argument expression being passed to a parameter of
7266 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7267 zero-based argument number. Do any required conversions. Return
7268 the converted value. */
7271 void
7275 void
7279 tree
7281 tsubst_flags_t complain)
7282 {
7284 tree t;
7286 /* See through clones. */
7288 /* And inheriting ctors. */
7292 /* Detect recursion. */
7295 {
7299 }
7301 /* If the ARG is an unparsed default argument expression, the
7302 conversion cannot be performed. */
7304 {
7309 }
7316 /* Due to:
7318 [dcl.fct.default]
7320 The names in the expression are bound, and the semantic
7321 constraints are checked, at the point where the default
7322 expressions appears.
7324 we must not perform access checks here. */
7326 /* We must make a copy of ARG, in case subsequent processing
7327 alters any part of it. */
7331 complain);
7338 }
7340 /* Returns the type which will really be used for passing an argument of
7341 type TYPE. */
7343 tree
7345 {
7346 /* Pass classes with copy ctors by invisible reference. */
7348 {
7350 /* There are no other pointers to this temporary. */
7352 }
7360 }
7362 /* Actually perform the appropriate conversion. */
7364 tree
7366 {
7367 tree bitfield_type;
7369 /* If VAL is a bitfield, then -- since it has already been converted
7370 to TYPE -- it cannot have a precision greater than TYPE.
7372 If it has a smaller precision, we must widen it here. For
7373 example, passing "int f:3;" to a function expecting an "int" will
7374 not result in any conversion before this point.
7376 If the precision is the same we must not risk widening. For
7377 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7378 often have type "int", even though the C++ type for the field is
7379 "long long". If the value is being passed to a function
7380 expecting an "int", then no conversions will be required. But,
7381 if we call convert_bitfield_to_declared_type, the bitfield will
7382 be converted to "long long". */
7389 ;
7390 /* Pass classes with copy ctors by invisible reference. */
7399 {
7401 {
7409 "argument of function call might be a candidate "
7411 }
7413 }
7415 }
7417 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7418 which just decay_conversion or no conversions at all should be done.
7419 This is true for some builtins which don't act like normal functions.
7420 Return 2 if no conversions at all should be done, 1 if just
7421 decay_conversion. Return 3 for special treatment of the 3rd argument
7422 for __builtin_*_overflow_p. */
7424 int
7426 {
7429 {
7444 }
7447 }
7449 /* Returns the decl of the dispatcher function if FN is a function version. */
7451 tree
7453 {
7463 {
7467 }
7472 }
7474 /* fn is a function version dispatcher that is marked used. Mark all the
7475 semantically identical function versions it will dispatch as used. */
7477 void
7479 {
7496 /* All semantically identical versions are chained. Traverse and mark each
7497 one of them as used. */
7500 {
7503 }
7504 }
7506 /* Build a call to "the copy constructor" for the type of A, even if it
7507 wouldn't be selected by normal overload resolution. Used for
7508 diagnostics. */
7510 static tree
7512 {
7523 }
7525 /* Return true iff T refers to a base field. */
7527 static bool
7529 {
7538 }
7540 /* We can't elide a copy from a function returning by value to a base
7541 subobject, as the callee might clobber tail padding. Return true iff this
7542 could be that case. */
7544 static bool
7546 {
7547 /* Copy elision only happens with a TARGET_EXPR. */
7551 /* It's safe to elide the copy for a class with no tail padding. */
7554 /* It's safe to elide the copy if we aren't initializing a base object. */
7558 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7563 }
7565 /* Subroutine of the various build_*_call functions. Overload resolution
7566 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7567 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7568 bitmask of various LOOKUP_* flags which apply to the call itself. */
7570 static tree
7572 {
7580 tree val;
7589 /* In a template, there is no need to perform all of the work that
7590 is normally done. We are only interested in the type of the call
7591 expression, i.e., the return type of the function. Any semantic
7592 errors will be deferred until the template is instantiated. */
7594 {
7596 tree return_type;
7607 else
7608 {
7611 tree arg;
7619 }
7629 }
7631 /* Give any warnings we noticed during overload resolution. */
7633 {
7637 }
7639 /* OK, we're actually calling this inherited constructor; set its deletedness
7640 appropriately. We can get away with doing this here because calling is
7641 the only way to refer to a constructor. */
7645 /* Make =delete work with SFINAE. */
7650 {
7651 tree access_fn;
7652 /* If FN is a template function, two cases must be considered.
7653 For example:
7655 struct A {
7656 protected:
7657 template <class T> void f();
7658 };
7659 template <class T> struct B {
7660 protected:
7661 void g();
7662 };
7663 struct C : A, B<int> {
7664 using A::f; // #1
7665 using B<int>::g; // #2
7666 };
7668 In case #1 where `A::f' is a member template, DECL_ACCESS is
7669 recorded in the primary template but not in its specialization.
7670 We check access of FN using its primary template.
7672 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7673 because it is a member of class template B, DECL_ACCESS is
7674 recorded in the specialization `B<int>::g'. We cannot use its
7675 primary template because `B<T>::g' and `B<int>::g' may have
7676 different access. */
7680 else
7685 }
7687 /* If we're checking for implicit delete, don't bother with argument
7688 conversions. */
7690 {
7692 {
7696 }
7700 /* Reject bad conversions now. */
7702 /* else continue to get conversion error. */
7703 }
7705 /* N3276 magic doesn't apply to nested calls. */
7708 /* No-Cleanup doesn't apply to nested calls either. */
7712 /* Find maximum size of vector to hold converted arguments. */
7719 /* The implicit parameters to a constructor are not considered by overload
7720 resolution, and must be of the proper type. */
7722 {
7723 tree object_arg;
7725 {
7728 }
7729 else
7730 {
7733 }
7736 /* We should never try to call the abstract constructor. */
7740 {
7744 }
7747 {
7748 /* The implicit move specified in 15.8.3/3 fails "...if the type of
7749 the first parameter of the selected constructor is not an rvalue
7750 reference to the object’s type (possibly cv-qualified)...." */
7757 }
7758 }
7759 /* Bypass access control for 'this' parameter. */
7761 {
7764 ? first_arg
7767 tree converted_arg;
7768 tree base_binfo;
7774 {
7776 {
7781 }
7782 else
7784 }
7786 /* See if the function member or the whole class type is declared
7787 final and the call can be devirtualized. */
7792 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7793 X is called for an object that is not of type X, or of a type
7794 derived from X, the behavior is undefined.
7796 So we can assume that anything passed as 'this' is non-null, and
7797 optimize accordingly. */
7799 /* Convert to the base in which the function was declared. */
7802 arg,
7805 /* Check that the base class is accessible. */
7808 {
7813 else
7815 }
7816 /* If fn was found by a using declaration, the conversion path
7817 will be to the derived class, not the base declaring fn. We
7818 must convert from derived to base. */
7829 else
7833 }
7838 {
7845 /* If the argument is NULL and used to (implicitly) instantiate a
7846 template function (and bind one of the template arguments to
7847 the type of 'long int'), we don't want to warn about passing NULL
7848 to non-pointer argument.
7849 For example, if we have this template function:
7851 template<typename T> void func(T x) {}
7853 we want to warn (when -Wconversion is enabled) in this case:
7855 void foo() {
7856 func<int>(NULL);
7857 }
7859 but not in this case:
7861 void foo() {
7862 func(NULL);
7863 }
7864 */
7871 /* Warn about initializer_list deduction that isn't currently in the
7872 working draft. */
7874 && flag_deduce_init_list
7878 {
7891 {
7899 }
7900 }
7902 /* Set user_conv_p on the argument conversions, so rvalue/base handling
7903 knows not to allow any more UDCs. This needs to happen after we
7904 process cand->warnings. */
7913 arg_complain);
7918 else
7920 }
7922 /* Default arguments */
7924 {
7930 complain);
7934 }
7936 /* Ellipsis */
7939 {
7942 {
7943 /* Do no conversions for certain magic varargs. */
7947 }
7949 /* For other magic varargs only do decay_conversion. */
7954 {
7955 /* Avoid infinite recursion trying to call A(...). */
7957 /* Try to call the actual copy constructor for a good error. */
7960 }
7961 else
7966 }
7971 /* Avoid to do argument-transformation, if warnings for format, and for
7972 nonnull are disabled. Just in case that at least one of them is active
7973 the check_function_arguments function might warn about something. */
7977 || warn_format
7978 || warn_suggest_attribute_format
7980 {
7988 }
7991 {
7992 /* Check for passing ellipsis arguments to an inherited constructor. We
7993 could handle this by open-coding the inherited constructor rather than
7994 defining it, but let's not bother now. */
7998 {
8000 {
8004 }
8006 }
8008 /* A base constructor inheriting from a virtual base doesn't get the
8009 inherited arguments, just this and __vtt. */
8012 }
8014 /* Avoid actually calling copy constructors and copy assignment operators,
8015 if possible. */
8022 /* It's unsafe to elide the constructor when handling
8023 a noexcept-expression, it may evaluate to the wrong
8024 value (c++/53025). */
8026 {
8027 tree targ;
8029 tree fa;
8032 /* Pull out the real argument, disregarding const-correctness. */
8034 /* Strip the reference binding for the constructor parameter. */
8038 /* But don't strip any other reference bindings; binding a temporary to a
8039 reference prevents copy elision. */
8045 {
8050 }
8051 else
8056 else
8059 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8060 subobject. */
8063 /* It's from binding the ref parm to a packed field. */
8066 /* See unsafe_copy_elision_p. */
8069 /* [class.copy]: the copy constructor is implicitly defined even if
8070 the implementation elided its use. */
8072 {
8076 }
8078 /* If we're creating a temp and we already have one, don't create a
8079 new one. If we're not creating a temp but we get one, use
8080 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8081 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8082 temp or an INIT_EXPR otherwise. */
8085 {
8090 }
8093 {
8098 }
8099 }
8104 {
8105 tree to = cp_stabilize_reference
8112 {
8113 /* Avoid copying empty classes. */
8116 }
8118 {
8121 /* Handle NSDMI that refer to the object being initialized. */
8123 }
8124 else
8125 {
8126 /* We must only copy the non-tail padding parts. */
8134 build_index_type
8143 }
8146 }
8149 {
8153 {
8156 no_cleanup_complain);
8157 else
8159 }
8160 }
8162 /* For calls to a multi-versioned function, overload resolution
8163 returns the function with the highest target priority, that is,
8164 the version that will checked for dispatching first. If this
8165 version is inlinable, a direct call to this version can be made
8166 otherwise the call should go through the dispatcher. */
8171 {
8177 }
8184 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8185 virtual functions can't be constexpr. */
8187 {
8188 tree t;
8195 complain);
8201 }
8202 else
8203 {
8207 }
8213 {
8215 /* build_new_op_1 will clear this when appropriate. */
8217 }
8219 {
8223 }
8225 }
8227 /* Return the DECL of the first non-public data member of class TYPE
8228 or null if none can be found. */
8230 static tree
8232 {
8237 {
8244 }
8250 {
8255 }
8258 }
8260 /* Return true if all copy and move assignment operator overloads for
8261 class TYPE are trivial and at least one of them is not deleted and,
8262 when ACCESS is set, accessible. Return false otherwise. Set
8263 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8264 copy or move assignment. */
8266 static bool
8268 {
8272 /* Iterate over overloads of the assignment operator, checking
8273 accessible copy assignments for triviality. */
8276 {
8279 /* Skip operators that aren't copy assignments. */
8286 /* Skip template assignment operators and deleted functions. */
8296 /* Break early when both properties have been determined. */
8299 }
8301 /* Return true if they're all trivial and one of the expressions
8302 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8307 }
8309 /* Return true if all copy and move ctor overloads for class TYPE are
8310 trivial and at least one of them is not deleted and, when ACCESS is
8311 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8312 to true when the TYPE has a (not necessarily trivial) default and copy
8313 (or move) ctor, respectively. */
8315 static bool
8317 {
8322 {
8325 /* Skip template constructors. */
8331 /* Skip ctors other than default, copy, and move. */
8347 /* Break early when both properties have been determined. */
8350 }
8353 }
8355 /* Issue a warning on a call to the built-in function FNDECL if it is
8356 a raw memory write whose destination is not an object of (something
8357 like) trivial or standard layout type with a non-deleted assignment
8358 and copy ctor. Detects const correctness violations, corrupting
8359 references, virtual table pointers, and bypassing non-trivial
8360 assignments. */
8362 static void
8364 {
8365 /* Except for bcopy where it's second, the destination pointer is
8366 the first argument for all functions handled here. Compute
8367 the index of the destination and source arguments. */
8375 /* Remove the outermost (usually implicit) conversion to the void*
8376 argument type. */
8382 /* Determine the type of the pointed-to object and whether it's
8383 a complete class type. */
8389 /* Check to see if the raw memory call is made by a ctor or dtor
8390 with this as the destination argument for the destination type.
8391 If so, be more permissive. */
8396 {
8402 /* A ctor and dtor for a class with no bases and no virtual functions
8403 can do whatever they want. Bail early with no further checking. */
8406 }
8408 /* True if the class is trivial. */
8411 /* Set to true if DESTYPE has an accessible copy assignment. */
8413 /* True if all of the class' overloaded copy assignment operators
8414 are all trivial (and not deleted) and at least one of them is
8415 accessible. */
8418 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8419 respectively. */
8422 /* True if all of the class' overloaded copy constructors are all
8423 trivial (and not deleted) and at least one of them is accessible. */
8426 /* Set FLD to the first private/protected member of the class. */
8429 /* The warning format string. */
8431 /* A suggested alternative to offer instead of the raw memory call.
8432 Empty string when none can be come up with. */
8437 {
8440 {
8441 /* Diagnose setting non-copy-assignable or non-trivial types,
8442 or types with a private member, to (potentially) non-zero
8443 bytes. Since the value of the bytes being written is unknown,
8444 suggest using assignment instead (if one exists). Also warn
8445 for writes into objects for which zero-initialization doesn't
8446 mean all bits clear (pointer-to-member data, where null is all
8447 bits set). Since the value being written is (most likely)
8448 non-zero, simply suggest assignment (but not copy assignment). */
8456 {
8459 "%qD writing to an object of type %#qT with "
8462 }
8468 }
8469 /* Fall through. */
8472 /* Similarly to the above, diagnose clearing non-trivial or non-
8473 standard layout objects, or objects of types with no assignmenmt.
8474 Since the value being written is known to be zero, suggest either
8475 copy assignment, copy ctor, or default ctor as an alternative,
8476 depending on what's available. */
8499 /* Determine the type of the source object. */
8503 /* Since it's impossible to determine wheter the byte copy is
8504 being used in place of assignment to an existing object or
8505 as a substitute for initialization, assume it's the former.
8506 Determine the best alternative to use instead depending on
8507 what's not deleted. */
8528 srctype))
8529 {
8530 /* Warn when copying into a non-trivial object from an object
8531 of a different type other than void or char. */
8533 "%qD copying an object of non-trivial type "
8536 }
8541 srctype))
8542 {
8545 "%qD copying an object of type %#qT with "
8546 "%qs member %qD from an array of %#qT; use "
8549 }
8551 {
8552 /* Finally, warn on partial copies. */
8553 unsigned HOST_WIDE_INT typesize
8560 "a non-trivial type %#qT leaves %wu "
8563 "a non-trivial type %#qT leaves %wu "
8566 }
8583 {
8584 /* Finally, warn on reallocation into insufficient space. */
8586 "%qD moving an object of non-trivial type "
8590 }
8595 }
8601 {
8605 else
8608 }
8612 }
8614 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8615 This function performs no overload resolution, conversion, or other
8616 high-level operations. */
8618 tree
8620 tsubst_flags_t complain)
8621 {
8622 tree fndecl;
8624 /* Remember roughly where this call is. */
8631 /* Check that arguments to builtin functions match the expectations. */
8635 {
8638 /* We need to take care that values to BUILT_IN_NORMAL
8639 are reduced. */
8647 /* Warn if the built-in writes to an object of a non-trivial type. */
8650 }
8655 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8656 function call is either the operand of a decltype-specifier or the
8657 right operand of a comma operator that is the operand of a
8658 decltype-specifier, a temporary object is not introduced for the
8659 prvalue. The type of the prvalue may be incomplete. */
8661 {
8667 {
8670 }
8671 }
8673 }
8675 /* Returns the value to use for the in-charge parameter when making a
8676 call to a function with the indicated NAME.
8678 FIXME:Can't we find a neater way to do this mapping? */
8680 tree
8682 {
8684 {
8688 }
8689 else
8690 {
8696 }
8699 }
8701 /* We've built up a constructor call RET. Complain if it delegates to the
8702 constructor we're currently compiling. */
8704 static void
8706 {
8712 }
8714 /* Build a call to a constructor, destructor, or an assignment
8715 operator for INSTANCE, an expression with class type. NAME
8716 indicates the special member function to call; *ARGS are the
8717 arguments. ARGS may be NULL. This may change ARGS. BINFO
8718 indicates the base of INSTANCE that is to be passed as the `this'
8719 parameter to the member function called.
8721 FLAGS are the LOOKUP_* flags to use when processing the call.
8723 If NAME indicates a complete object constructor, INSTANCE may be
8724 NULL_TREE. In this case, the caller will call build_cplus_new to
8725 store the newly constructed object into a VAR_DECL. */
8727 tree
8730 {
8731 tree fns;
8732 /* The type of the subobject to be constructed or destroyed. */
8733 tree class_type;
8735 tree ret;
8739 {
8740 /* Resolve the name. */
8745 }
8751 /* Handle the special case where INSTANCE is NULL_TREE. */
8754 else
8755 {
8759 /* Convert to the base class, if necessary. */
8762 {
8764 /* For constructors and destructors, either the base is
8765 non-virtual, or it is virtual but we are doing the
8766 conversion from a constructor or destructor for the
8767 complete object. In either case, we can convert
8768 statically. */
8770 else
8771 {
8772 /* However, for assignment operators, we must convert
8773 dynamically if the base is virtual. */
8777 }
8778 }
8779 }
8783 /* In C++17, "If the initializer expression is a prvalue and the
8784 cv-unqualified version of the source type is the same class as the class
8785 of the destination, the initializer expression is used to initialize the
8786 destination object." Handle that here to avoid doing overload
8787 resolution. */
8791 {
8794 /* FIXME P0135 doesn't say how to handle direct initialization from a
8795 type with a suitable conversion operator. Let's handle it like
8796 copy-initialization, but allowing explict conversions. */
8799 /* If we're using this to initialize a non-temporary object, don't
8800 require the destructor to be accessible. */
8804 sub_complain,
8805 flags);
8808 && (same_type_ignoring_top_level_qualifiers_p
8810 {
8816 /* Avoid change of behavior on Wunused-var-2.C. */
8819 }
8820 }
8824 /* When making a call to a constructor or destructor for a subobject
8825 that uses virtual base classes, pass down a pointer to a VTT for
8826 the subobject. */
8830 {
8831 tree vtt;
8832 tree sub_vtt;
8834 /* If the current function is a complete object constructor
8835 or destructor, then we fetch the VTT directly.
8836 Otherwise, we look it up using the VTT we were given. */
8844 else
8848 {
8851 }
8854 }
8859 complain);
8870 }
8872 /* Return the NAME, as a C string. The NAME indicates a function that
8873 is a member of TYPE. *FREE_P is set to true if the caller must
8874 free the memory returned.
8876 Rather than go through all of this, we should simply set the names
8877 of constructors and destructors appropriately, and dispense with
8878 ctor_identifier, dtor_identifier, etc. */
8882 {
8885 /* Assume that we will not allocate memory. */
8887 /* Constructors and destructors are special. */
8889 {
8890 pretty_name
8892 /* For a destructor, add the '~'. */
8894 {
8896 /* Remember that we need to free the memory allocated. */
8898 }
8899 }
8901 {
8904 TFF_PLAIN_IDENTIFIER),
8905 NULL);
8906 /* Remember that we need to free the memory allocated. */
8908 }
8909 else
8913 }
8915 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
8916 be set, upon return, to the function called. ARGS may be NULL.
8917 This may change ARGS. */
8919 static tree
8923 {
8928 tree optype;
8930 tree name;
8933 tree call;
8934 tree fn;
8937 tree orig_instance;
8938 tree orig_fns;
8944 /* We don't know what function we're going to call, yet. */
8953 {
8957 }
8962 /* Dismantle the baselink to collect all the information we need. */
8970 {
8974 }
8985 {
8990 }
8993 /* Under DR 147 A::A() is an invalid constructor call,
8994 not a functional cast. */
8996 {
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. */
9024 /* Figure out whether to skip the first argument for the error
9025 message we will display to users if an error occurs. We don't
9026 want to display any compiler-generated arguments. The "this"
9027 pointer hasn't been added yet. However, we must remove the VTT
9028 pointer if this is a call to a base-class constructor or
9029 destructor. */
9032 {
9033 /* Callers should explicitly indicate whether they want to ctor
9034 the complete object or just the part without virtual bases. */
9037 /* Remove the VTT pointer, if present. */
9042 /* It's OK to call destructors and constructors on cv-qualified
9043 objects. Therefore, convert the INSTANCE to the unqualified
9044 type, if necessary. */
9046 {
9050 }
9051 }
9052 else
9055 /* For the overload resolution we need to find the actual `this`
9056 that would be captured if the call turns out to be to a
9057 non-static member function. Do not actually capture it at this
9058 point. */
9060 /* Constructors don't use the enclosing 'this'. */
9062 else
9065 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9068 /* The number of arguments artificial parms in ARGS; we subtract one because
9069 there's no 'this' in ARGS. */
9072 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9073 initializer, not T({ }). */
9077 {
9084 /* If the initializer list has no elements and T is a class type with
9085 a default constructor, the object is value-initialized. Handle
9086 this here so we don't need to handle it wherever we use
9087 build_special_member_call. */
9090 /* For a user-provided default constructor, use the normal
9091 mechanisms so that protected access works. */
9096 /* If BASETYPE is an aggregate, we need to do aggregate
9097 initialization. */
9099 {
9102 }
9105 {
9111 }
9113 /* Otherwise go ahead with overload resolution. */
9118 }
9119 else
9128 {
9130 {
9137 else
9138 {
9143 {
9146 }
9154 }
9156 }
9158 }
9159 else
9160 {
9163 {
9166 tree arglist;
9169 {
9177 else
9183 }
9185 }
9186 else
9187 {
9195 {
9196 /* This is not an error, it is runtime undefined
9197 behavior. */
9206 fn);
9207 }
9212 {
9217 {
9218 /* We captured 'this' in the current lambda now that
9219 we know we really need it. */
9221 }
9223 /* We can't tell until instantiation time whether we can use
9225 else
9226 {
9229 fn);
9231 }
9232 }
9235 {
9236 /* Optimize away vtable lookup if we know that this
9237 function can't be overridden. We need to check if
9238 the context and the type where we found fn are the same,
9239 actually FN might be defined in a different class
9240 type because of a using-declaration. In this case, we
9241 do not want to perform a non-virtual call. */
9243 && same_type_ignoring_top_level_qualifiers_p
9249 /* Now we know what function is being called. */
9252 /* Build the actual CALL_EXPR. */
9254 /* In an expression of the form `a->f()' where `f' turns
9255 out to be a static member function, `a' is
9256 none-the-less evaluated. */
9265 /* An explicit call of the form "x->~X()" has type
9266 "void". However, on platforms where destructors
9267 return "this" (i.e., those where
9268 targetm.cxx.cdtor_returns_this is true), such calls
9269 will appear to have a return value of pointer type
9270 to the low-level call machinery. We do not want to
9271 change the low-level machinery, since we want to be
9272 able to optimize "delete f()" on such platforms as
9273 "operator delete(~X(f()))" (rather than generating
9274 "t = f(), ~X(t), operator delete (t)"). */
9276 }
9277 }
9278 }
9281 {
9287 {
9290 }
9293 call = (build_min_non_dep_call_vec
9297 orig_args));
9302 }
9304 /* Free all the conversions we allocated. */
9311 }
9313 /* Wrapper for above. */
9315 tree
9319 {
9320 tree ret;
9326 }
9328 /* Returns true iff standard conversion sequence ICS1 is a proper
9329 subsequence of ICS2. */
9331 static bool
9333 {
9334 /* We can assume that a conversion of the same code
9335 between the same types indicates a subsequence since we only get
9336 here if the types we are converting from are the same. */
9343 {
9353 /* At this point, ICS1 cannot be a proper subsequence of
9354 ICS2. We can get a USER_CONV when we are comparing the
9355 second standard conversion sequence of two user conversion
9356 sequences. */
9371 }
9372 }
9374 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9375 be any _TYPE nodes. */
9377 bool
9379 {
9383 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9384 considers every class derived from itself. */
9387 }
9389 /* We build the ICS for an implicit object parameter as a pointer
9390 conversion sequence. However, such a sequence should be compared
9391 as if it were a reference conversion sequence. If ICS is the
9392 implicit conversion sequence for an implicit object parameter,
9393 modify it accordingly. */
9395 static void
9397 {
9399 {
9400 /* [over.match.funcs]
9402 For non-static member functions, the type of the
9403 implicit object parameter is "reference to cv X"
9404 where X is the class of which the function is a
9405 member and cv is the cv-qualification on the member
9406 function declaration. */
9408 tree reference_type;
9410 /* The `this' parameter is a pointer to a class type. Make the
9411 implicit conversion talk about a reference to that same class
9412 type. */
9425 }
9426 }
9428 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9429 and return the initial reference binding conversion. Otherwise,
9430 leave *ICS unchanged and return NULL. */
9434 {
9436 {
9441 }
9444 }
9446 /* Compare two implicit conversion sequences according to the rules set out in
9447 [over.ics.rank]. Return values:
9449 1: ics1 is better than ics2
9450 -1: ics2 is better than ics1
9451 0: ics1 and ics2 are indistinguishable */
9453 static int
9455 {
9456 tree from_type1;
9457 tree from_type2;
9458 tree to_type1;
9459 tree to_type2;
9466 /* REF_BINDING is nonzero if the result of the conversion sequence
9467 is a reference type. In that case REF_CONV is the reference
9468 binding conversion. */
9472 /* Compare badness before stripping the reference conversion. */
9478 /* Handle implicit object parameters. */
9482 /* Handle reference parameters. */
9486 /* List-initialization sequence L1 is a better conversion sequence than
9487 list-initialization sequence L2 if L1 converts to
9488 std::initializer_list<X> for some X and L2 does not. */
9494 /* [over.ics.rank]
9496 When comparing the basic forms of implicit conversion sequences (as
9497 defined in _over.best.ics_)
9499 --a standard conversion sequence (_over.ics.scs_) is a better
9500 conversion sequence than a user-defined conversion sequence
9501 or an ellipsis conversion sequence, and
9503 --a user-defined conversion sequence (_over.ics.user_) is a
9504 better conversion sequence than an ellipsis conversion sequence
9505 (_over.ics.ellipsis_). */
9506 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9507 mismatch. If both ICS are bad, we try to make a decision based on
9508 what would have happened if they'd been good. This is not an
9509 extension, we'll still give an error when we build up the call; this
9510 just helps us give a more helpful error message. */
9520 /* Both conversions are ellipsis conversions. */
9523 /* User-defined conversion sequence U1 is a better conversion sequence
9524 than another user-defined conversion sequence U2 if they contain the
9525 same user-defined conversion operator or constructor and if the sec-
9526 ond standard conversion sequence of U1 is better than the second
9527 standard conversion sequence of U2. */
9529 /* Handle list-conversion with the same code even though it isn't always
9530 ranked as a user-defined conversion and it doesn't have a second
9531 standard conversion sequence; it will still have the desired effect.
9532 Specifically, we need to do the reference binding comparison at the
9533 end of this function. */
9536 {
9552 {
9557 }
9558 else
9559 {
9560 /* For ambiguous or aggregate conversions, use the target type as
9561 a proxy for the conversion function. */
9564 }
9566 /* We can just fall through here, after setting up
9567 FROM_TYPE1 and FROM_TYPE2. */
9570 }
9571 else
9572 {
9576 /* We're dealing with two standard conversion sequences.
9578 [over.ics.rank]
9580 Standard conversion sequence S1 is a better conversion
9581 sequence than standard conversion sequence S2 if
9583 --S1 is a proper subsequence of S2 (comparing the conversion
9584 sequences in the canonical form defined by _over.ics.scs_,
9585 excluding any Lvalue Transformation; the identity
9586 conversion sequence is considered to be a subsequence of
9587 any non-identity conversion sequence */
9598 }
9600 /* One sequence can only be a subsequence of the other if they start with
9601 the same type. They can start with different types when comparing the
9602 second standard conversion sequence in two user-defined conversion
9603 sequences. */
9605 {
9610 }
9612 /* [over.ics.rank]
9614 Or, if not that,
9616 --the rank of S1 is better than the rank of S2 (by the rules
9617 defined below):
9619 Standard conversion sequences are ordered by their ranks: an Exact
9620 Match is a better conversion than a Promotion, which is a better
9621 conversion than a Conversion.
9623 Two conversion sequences with the same rank are indistinguishable
9624 unless one of the following rules applies:
9626 --A conversion that does not a convert a pointer, pointer to member,
9627 or std::nullptr_t to bool is better than one that does.
9629 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9630 so that we do not have to check it explicitly. */
9639 /* A conversion from scalar arithmetic type to complex is worse than a
9640 conversion between scalar arithmetic types. */
9647 {
9650 else
9652 }
9658 {
9663 }
9664 /* The rules for pointers to members A::* are just like the rules
9665 for pointers A*, except opposite: if B is derived from A then
9666 A::* converts to B::*, not vice versa. For that reason, we
9667 switch the from_ and to_ variables here. */
9674 {
9679 }
9684 {
9685 /* This was one of the pointer or pointer-like conversions.
9687 [over.ics.rank]
9689 --If class B is derived directly or indirectly from class A,
9690 conversion of B* to A* is better than conversion of B* to
9691 void*, and conversion of A* to void* is better than
9692 conversion of B* to void*. */
9695 {
9697 deref_from_type2))
9700 deref_from_type1))
9702 }
9705 {
9707 {
9709 {
9711 deref_to_type1))
9713 }
9714 /* We know that DEREF_TO_TYPE1 is `void' here. */
9716 deref_to_type2))
9718 }
9719 }
9722 {
9723 /* [over.ics.rank]
9725 --If class B is derived directly or indirectly from class A
9726 and class C is derived directly or indirectly from B,
9728 --conversion of C* to B* is better than conversion of C* to
9729 A*,
9731 --conversion of B* to A* is better than conversion of C* to
9732 A* */
9734 {
9736 deref_to_type2))
9739 deref_to_type1))
9741 }
9743 {
9745 deref_from_type1))
9748 deref_from_type2))
9750 }
9751 }
9752 }
9755 {
9758 /* [over.ics.rank]
9760 --binding of an expression of type C to a reference of type
9761 B& is better than binding an expression of type C to a
9762 reference of type A&
9764 --conversion of C to B is better than conversion of C to A, */
9767 {
9772 }
9773 }
9776 {
9779 /* [over.ics.rank]
9781 --binding of an expression of type B to a reference of type
9782 A& is better than binding an expression of type C to a
9783 reference of type A&,
9785 --conversion of B to A is better than conversion of C to A */
9788 {
9793 }
9794 }
9796 /* [over.ics.rank]
9798 --S1 and S2 differ only in their qualification conversion and yield
9799 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
9800 qualification signature of type T1 is a proper subset of the cv-
9801 qualification signature of type T2 */
9805 {
9809 }
9811 /* [over.ics.rank]
9813 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
9814 to an implicit object parameter of a non-static member function
9815 declared without a ref-qualifier, and either S1 binds an lvalue
9816 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
9817 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
9818 draft standard, 13.3.3.2)
9820 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
9821 types to which the references refer are the same type except for
9822 top-level cv-qualifiers, and the type to which the reference
9823 initialized by S2 refers is more cv-qualified than the type to
9824 which the reference initialized by S1 refers.
9826 DR 1328 [over.match.best]: the context is an initialization by
9827 conversion function for direct reference binding (13.3.1.6) of a
9828 reference to function type, the return type of F1 is the same kind of
9829 reference (i.e. lvalue or rvalue) as the reference being initialized,
9830 and the return type of F2 is not. */
9833 {
9840 {
9844 /* Don't prefer a bad conversion that drops cv-quals to a bad
9845 conversion with the wrong rvalueness. */
9849 }
9852 {
9856 {
9857 /* Prefer the one that drops fewer cv-quals. */
9862 }
9864 }
9865 }
9867 /* Neither conversion sequence is better than the other. */
9869 }
9871 /* The source type for this standard conversion sequence. */
9873 static tree
9875 {
9877 {
9882 }
9884 }
9886 /* Note a warning about preferring WINNER to LOSER. We do this by storing
9887 a pointer to LOSER and re-running joust to produce the warning if WINNER
9888 is actually used. */
9890 static void
9892 {
9898 }
9900 /* Compare two candidates for overloading as described in
9901 [over.match.best]. Return values:
9903 1: cand1 is better than cand2
9904 -1: cand2 is better than cand1
9905 0: cand1 and cand2 are indistinguishable */
9907 static int
9909 tsubst_flags_t complain)
9910 {
9916 /* Candidates that involve bad conversions are always worse than those
9917 that don't. */
9923 /* If we have two pseudo-candidates for conversions to the same type,
9924 or two candidates for the same function, arbitrarily pick one. */
9929 /* Prefer a non-deleted function over an implicitly deleted move
9930 constructor or assignment operator. This differs slightly from the
9931 wording for issue 1402 (which says the move op is ignored by overload
9932 resolution), but this way produces better error messages. */
9936 {
9943 }
9945 /* a viable function F1
9946 is defined to be a better function than another viable function F2 if
9947 for all arguments i, ICSi(F1) is not a worse conversion sequence than
9948 ICSi(F2), and then */
9950 /* for some argument j, ICSj(F1) is a better conversion sequence than
9951 ICSj(F2) */
9953 /* For comparing static and non-static member functions, we ignore
9954 the implicit object parameter of the non-static function. The
9955 standard says to pretend that the static function has an object
9956 parm, but that won't work with operator overloading. */
9959 {
9965 /* We're comparing a near-match list constructor and a near-match
9966 non-list constructor. Just treat them as unordered. */
9973 else
9974 {
9977 }
9978 }
9981 {
9987 {
9989 && warn_sign_promo
10001 {
10008 else
10013 {
10017 }
10018 else
10020 }
10023 {
10026 }
10028 }
10029 }
10031 /* warn about confusing overload resolution for user-defined conversions,
10032 either between a constructor and a conversion op, or between two
10033 conversion ops. */
10038 {
10044 else
10047 /* We don't want to complain about `X::operator T1 ()'
10048 beating `X::operator T2 () const', when T2 is a no less
10049 cv-qualified version of T1. */
10052 {
10057 {
10060 }
10063 }
10064 else
10070 {
10077 {
10079 }
10080 }
10081 else
10083 }
10088 /* DR 495 moved this tiebreaker above the template ones. */
10089 /* or, if not that,
10090 the context is an initialization by user-defined conversion (see
10091 _dcl.init_ and _over.match.user_) and the standard conversion
10092 sequence from the return type of F1 to the destination type (i.e.,
10093 the type of the entity being initialized) is a better conversion
10094 sequence than the standard conversion sequence from the return type
10095 of F2 to the destination type. */
10098 {
10102 }
10104 /* or, if not that,
10105 F1 is a non-template function and F2 is a template function
10106 specialization. */
10113 /* or, if not that,
10114 F1 and F2 are template functions and the function template for F1 is
10115 more specialized than the template for F2 according to the partial
10116 ordering rules. */
10119 {
10120 winner = more_specialized_fn
10123 /* [temp.func.order]: The presence of unused ellipsis and default
10124 arguments has no effect on the partial ordering of function
10125 templates. add_function_candidate() will not have
10126 counted the "this" argument for constructors. */
10130 }
10132 // C++ Concepts
10133 // or, if not that, F1 is more constrained than F2.
10135 {
10139 }
10141 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10143 {
10145 /* We distinguish between candidates from an explicit deduction guide and
10146 candidates built from a constructor based on DECL_ARTIFICIAL. */
10153 {
10154 /* Prefer the special copy guide over a declared copy/move
10155 constructor. */
10161 /* Prefer a candidate generated from a non-template constructor. */
10166 }
10167 }
10169 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10170 for all arguments the corresponding parameters of F1 and F2 have the same
10171 type (CWG 2273/2277). */
10176 {
10190 {
10192 {
10197 }
10200 }
10201 }
10203 /* Check whether we can discard a builtin candidate, either because we
10204 have two identical ones or matching builtin and non-builtin candidates.
10206 (Pedantically in the latter case the builtin which matched the user
10207 function should not be added to the overload set, but we spot it here.
10209 [over.match.oper]
10210 ... the builtin candidates include ...
10211 - do not have the same parameter type list as any non-template
10212 non-member candidate. */
10215 {
10221 {
10223 /* Two built-in candidates; arbitrarily pick one. */
10226 /* cand1 is built-in; prefer cand2. */
10228 else
10229 /* cand2 is built-in; prefer cand1. */
10231 }
10232 }
10234 /* For candidates of a multi-versioned function, make the version with
10235 the highest priority win. This version will be checked for dispatching
10236 first. If this version can be inlined into the caller, the front-end
10237 will simply make a direct call to this function. */
10243 {
10249 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10250 is possible that cand1->fn and cand2->fn are function versions but of
10251 different functions. Check types to see if they are versions of the same
10252 function. */
10255 {
10256 /* Always make the version with the higher priority, more
10257 specialized, win. */
10261 else
10263 }
10264 }
10266 /* If the two function declarations represent the same function (this can
10267 happen with declarations in multiple scopes and arg-dependent lookup),
10268 arbitrarily choose one. But first make sure the default args we're
10269 using match. */
10272 {
10279 {
10280 /* Don't crash if the fn is variadic. */
10285 }
10293 {
10296 {
10298 {
10300 {
10302 "default argument mismatch in "
10304 {
10309 }
10310 }
10311 else
10313 }
10314 else
10317 }
10320 }
10323 }
10325 tweak:
10327 /* Extension: If the worst conversion for one candidate is worse than the
10328 worst conversion for the other, take the first. */
10330 {
10335 {
10340 }
10346 {
10347 /* Don't choose a deleted function over ambiguity. */
10351 {
10353 "ISO C++ says that these are ambiguous, even "
10354 "though the worst conversion for the first is better than "
10358 }
10359 else
10362 }
10363 }
10367 }
10369 /* Given a list of candidates for overloading, find the best one, if any.
10370 This algorithm has a worst case of O(2n) (winner is last), and a best
10371 case of O(n/2) (totally ambiguous); much better than a sorting
10372 algorithm. */
10376 {
10381 /* Walk through the list once, comparing each current champ to the next
10382 candidate, knocking out a candidate or two with each comparison. */
10385 {
10389 else
10390 {
10392 {
10397 }
10398 else
10399 {
10402 }
10405 }
10406 }
10408 /* Make sure the champ is better than all the candidates it hasn't yet
10409 been compared to. */
10412 challenger != champ
10415 {
10419 }
10422 }
10424 /* Returns nonzero if things of type FROM can be converted to TO. */
10426 bool
10428 {
10430 /* implicit_conversion only considers user-defined conversions
10431 if it has an expression for the call argument list. */
10435 }
10437 /* Returns nonzero if things of type FROM can be converted to TO with a
10438 standard conversion. */
10440 bool
10442 {
10444 }
10446 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10448 bool
10450 tsubst_flags_t complain)
10451 {
10456 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10458 /* We want to discard any access checks done for this test,
10459 as we might not be in the appropriate access context and
10460 we'll do the check again when we actually perform the
10461 conversion. */
10468 /* Discard the access checks now. */
10470 /* Free all the conversions we allocated. */
10474 }
10476 /* Like can_convert_arg, but allows dubious conversions as well. */
10478 bool
10480 tsubst_flags_t complain)
10481 {
10485 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10487 /* Try to perform the conversion. */
10490 /* Free all the conversions we allocated. */
10494 }
10496 /* Convert EXPR to TYPE. Return the converted expression.
10498 Note that we allow bad conversions here because by the time we get to
10499 this point we are committed to doing the conversion. If we end up
10500 doing a bad conversion, convert_like will complain. */
10502 tree
10505 {
10513 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10521 {
10523 {
10524 /* If expr has unknown type, then it is an overloaded function.
10525 Call instantiate_type to get good error messages. */
10530 else
10533 }
10535 }
10537 {
10538 /* In a template, we are only concerned about determining the
10539 type of non-dependent expressions, so we do not have to
10540 perform the actual conversion. But for initializers, we
10541 need to be able to perform it at instantiation
10542 (or instantiate_non_dependent_expr) time. */
10546 }
10547 else
10550 /* Free all the conversions we allocated. */
10554 }
10556 tree
10558 {
10560 LOOKUP_IMPLICIT);
10561 }
10563 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10564 permitted. If the conversion is valid, the converted expression is
10565 returned. Otherwise, NULL_TREE is returned, except in the case
10566 that TYPE is a class type; in that case, an error is issued. If
10567 C_CAST_P is true, then this direct-initialization is taking
10568 place as part of a static_cast being attempted as part of a C-style
10569 cast. */
10571 tree
10573 tree expr,
10575 tsubst_flags_t complain)
10576 {
10582 /* [dcl.init]
10584 If the destination type is a (possibly cv-qualified) class type:
10586 -- If the initialization is direct-initialization ...,
10587 constructors are considered. ... If no constructor applies, or
10588 the overload resolution is ambiguous, the initialization is
10589 ill-formed. */
10591 {
10597 }
10599 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10603 c_cast_p,
10608 {
10609 /* In a template, we are only concerned about determining the
10610 type of non-dependent expressions, so we do not have to
10611 perform the actual conversion. But for initializers, we
10612 need to be able to perform it at instantiation
10613 (or instantiate_non_dependent_expr) time. */
10616 }
10617 else
10620 c_cast_p,
10621 complain);
10623 /* Free all the conversions we allocated. */
10627 }
10629 /* When initializing a reference that lasts longer than a full-expression,
10630 this special rule applies:
10632 [class.temporary]
10634 The temporary to which the reference is bound or the temporary
10635 that is the complete object to which the reference is bound
10636 persists for the lifetime of the reference.
10638 The temporaries created during the evaluation of the expression
10639 initializing the reference, except the temporary to which the
10640 reference is bound, are destroyed at the end of the
10641 full-expression in which they are created.
10643 In that case, we store the converted expression into a new
10644 VAR_DECL in a new scope.
10646 However, we want to be careful not to create temporaries when
10647 they are not required. For example, given:
10649 struct B {};
10650 struct D : public B {};
10651 D f();
10652 const B& b = f();
10654 there is no need to copy the return value from "f"; we can just
10655 extend its lifetime. Similarly, given:
10657 struct S {};
10658 struct T { operator S(); };
10659 T t;
10660 const S& s = t;
10662 we can extend the lifetime of the return value of the conversion
10663 operator.
10665 The next several functions are involved in this lifetime extension. */
10667 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10668 reference is being bound to a temporary. Create and return a new
10669 VAR_DECL with the indicated TYPE; this variable will store the value to
10670 which the reference is bound. */
10672 tree
10674 {
10677 /* Register the variable. */
10680 {
10681 /* Namespace-scope or local static; give it a mangled name. */
10682 /* FIXME share comdat with decl? */
10693 }
10694 else
10695 /* Create a new cleanup level if necessary. */
10699 }
10701 /* EXPR is the initializer for a variable DECL of reference or
10702 std::initializer_list type. Create, push and return a new VAR_DECL
10703 for the initializer so that it will live as long as DECL. Any
10704 cleanup for the new variable is returned through CLEANUP, and the
10705 code to initialize the new variable is returned through INITP. */
10707 static tree
10710 {
10711 tree init;
10712 tree type;
10713 tree var;
10715 /* Create the temporary variable. */
10719 /* If the rvalue is the result of a function call it will be
10720 a TARGET_EXPR. If it is some other construct (such as a
10721 member access expression where the underlying object is
10722 itself the result of a function call), turn it into a
10723 TARGET_EXPR here. It is important that EXPR be a
10724 TARGET_EXPR below since otherwise the INIT_EXPR will
10725 attempt to make a bitwise copy of EXPR to initialize
10726 VAR. */
10732 {
10736 }
10738 /* Recursively extend temps in this initializer. */
10742 /* Any reference temp has a non-trivial initializer. */
10745 /* If the initializer is constant, put it in DECL_INITIAL so we get
10746 static initialization and use in constant expressions. */
10749 {
10751 {
10752 /* 5.19 says that a constant expression can include an
10753 lvalue-rvalue conversion applied to "a glvalue of literal type
10754 that refers to a non-volatile temporary object initialized
10755 with a constant expression". Rather than try to communicate
10756 that this VAR_DECL is a temporary, just mark it constexpr.
10758 Currently this is only useful for initializer_list temporaries,
10759 since reference vars can't appear in constant expressions. */
10763 }
10766 }
10767 else
10768 /* Create the INIT_EXPR that will initialize the temporary
10769 variable. */
10772 {
10777 else
10778 {
10782 }
10784 /* We must be careful to destroy the temporary only
10785 after its initialization has taken place. If the
10786 initialization throws an exception, then the
10787 destructor should not be run. We cannot simply
10788 transform INIT into something like:
10790 (INIT, ({ CLEANUP_STMT; }))
10792 because emit_local_var always treats the
10793 initializer as a full-expression. Thus, the
10794 destructor would run too early; it would run at the
10795 end of initializing the reference variable, rather
10796 than at the end of the block enclosing the
10797 reference variable.
10799 The solution is to pass back a cleanup expression
10800 which the caller is responsible for attaching to
10801 the statement tree. */
10802 }
10803 else
10804 {
10807 {
10810 tls_aggregates);
10811 else
10813 static_aggregates);
10814 }
10815 else
10816 /* Check whether the dtor is callable. */
10818 }
10819 /* Avoid -Wunused-variable warning (c++/38958). */
10826 }
10828 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
10829 initializing a variable of that TYPE. */
10831 tree
10834 {
10842 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10848 {
10850 {
10859 else
10863 }
10865 }
10868 /* Perform the conversion. */
10871 /* We gave an error in build_user_type_conversion_1. */
10873 else
10876 /* Free all the conversions we allocated. */
10880 }
10882 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
10883 which is bound either to a reference or a std::initializer_list. */
10885 static tree
10887 {
10892 {
10896 }
10899 /* Deal with binding to a subobject. */
10903 {
10911 }
10913 }
10915 /* INIT is part of the initializer for DECL. If there are any
10916 reference or initializer lists being initialized, extend their
10917 lifetime to match that of DECL. */
10919 tree
10921 {
10927 else
10928 {
10933 {
10935 {
10936 /* The temporary array underlying a std::initializer_list
10937 is handled like a reference temporary. */
10941 }
10942 else
10943 {
10949 }
10953 }
10954 }
10957 }
10959 /* Returns true iff an initializer for TYPE could contain temporaries that
10960 need to be extended because they are bound to references or
10961 std::initializer_list. */
10963 bool
10965 {
10970 {
10977 }
10979 }
10981 /* Returns true iff TYPE is some variant of std::initializer_list. */
10983 bool
10985 {
10990 /* Look through typedefs. */
10995 }
10997 /* Returns true iff DECL is a list constructor: i.e. a constructor which
10998 will accept an argument list of a single std::initializer_list<T>. */
11000 bool
11002 {
11004 tree arg;
11016 /* There are more non-defaulted parms. */
11020 }