| blob | 62654a9e40724232bb9fa015e1b8276b0cd67b75 |
1 /* Functions related to invoking -*- C++ -*- methods and overloaded functions.
2 Copyright (C) 1987-2018 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. If KIND is ck_ambig, true if the context is
97 copy-initialization. */
99 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
100 from a pointer-to-derived to pointer-to-base is being performed. */
102 /* If KIND is ck_ref_bind, true when either an lvalue reference is
103 being bound to an lvalue expression or an rvalue reference is
104 being bound to an rvalue expression. If KIND is ck_rvalue,
105 true when we are treating an lvalue as an rvalue (12.8p33). If
106 KIND is ck_base, always false. If ck_identity, we will be
107 binding a reference directly or decaying to a pointer. */
110 /* Whether check_narrowing should only check TREE_CONSTANTs; used
111 in build_converted_constant_expr. */
113 /* The type of the expression resulting from the conversion. */
114 tree type;
116 /* The next conversion in the chain. Since the conversions are
117 arranged from outermost to innermost, the NEXT conversion will
118 actually be performed before this conversion. This variant is
119 used only when KIND is neither ck_identity, ck_ambig nor
120 ck_list. Please use the next_conversion function instead
121 of using this field directly. */
123 /* The expression at the beginning of the conversion chain. This
124 variant is used only if KIND is ck_identity or ck_ambig. */
125 tree expr;
126 /* The array of conversions for an initializer_list, so this
127 variant is used only when KIN D is ck_list. */
130 /* The function candidate corresponding to this conversion
131 sequence. This field is only used if KIND is ck_user. */
133 };
135 #define CONVERSION_RANK(NODE) \
136 ((NODE)->bad_p ? cr_bad \
137 : (NODE)->ellipsis_p ? cr_ellipsis \
138 : (NODE)->user_conv_p ? cr_user \
139 : (NODE)->rank)
141 #define BAD_CONVERSION_RANK(NODE) \
142 ((NODE)->ellipsis_p ? cr_ellipsis \
143 : (NODE)->user_conv_p ? cr_user \
144 : (NODE)->rank)
153 tsubst_flags_t);
158 #define convert_like(CONV, EXPR, COMPLAIN) \
159 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, \
162 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
163 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), \
171 tsubst_flags_t);
183 static void add_builtin_candidates
186 static void add_builtin_candidate
190 static void build_builtin_candidate
200 tsubst_flags_t);
202 tsubst_flags_t);
222 tsubst_flags_t);
226 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
227 NAME can take many forms... */
229 bool
231 {
232 /* Just accept something we've already complained about. */
241 {
246 else
248 }
249 else
250 {
251 /* In the case of:
253 template <class T> struct S { ~S(); };
254 int i;
255 i.~S();
257 NAME will be a class template. */
260 }
265 }
267 /* We want the address of a function or method. We avoid creating a
268 pointer-to-member function. */
270 tree
272 {
275 /* We have to do these by hand to avoid real pointer to member
276 functions. */
278 {
280 {
284 complain);
285 }
287 }
288 else
292 }
294 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
295 POINTER_TYPE to those. Note, pointer to member function types
296 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
297 two variants. build_call_a is the primitive taking an array of
298 arguments, while build_call_n is a wrapper that handles varargs. */
300 tree
302 {
305 else
306 {
316 }
317 }
319 /* Update various flags in cfun and the call itself based on what is being
320 called. Split out of build_call_a so that bot_manip can use it too. */
322 void
324 {
325 /* Handle both CALL_EXPRs and AGGR_INIT_EXPRs. */
328 /* We check both the decl and the type; a function may be known not to
329 throw without being declared throw(). */
345 }
347 tree
349 {
350 tree decl;
351 tree result_type;
352 tree fntype;
362 /* An rvalue has no cv-qualifiers. */
373 {
374 /* We invoke build_call directly for several library
375 functions. These may have been declared normally if
376 we're building libgcc, so we can't just check
377 DECL_ARTIFICIAL. */
382 }
388 /* Don't pass empty class objects by value. This is useful
389 for tags in STL, which are used to control overload resolution.
390 We don't need to handle other cases of copying empty classes. */
393 {
397 {
401 }
402 }
405 }
407 /* New overloading code. */
414 };
416 /* Information for providing diagnostics about why overloading failed. */
419 rr_none,
420 rr_arity,
421 rr_explicit_conversion,
422 rr_template_conversion,
423 rr_arg_conversion,
424 rr_bad_arg_conversion,
425 rr_template_unification,
426 rr_invalid_copy,
427 rr_inherited_ctor,
428 rr_constraint_failure
429 };
432 /* The index of the argument, 0-based. */
434 /* The actual argument or its type. */
435 tree from;
436 /* The type of the parameter. */
437 tree to_type;
438 };
443 /* Information about an arity mismatch. */
445 /* The expected number of arguments. */
447 /* The actual number of arguments in the call. */
449 /* Whether the call was a varargs call. */
452 /* Information about an argument conversion mismatch. */
454 /* Same, but for bad argument conversions. */
456 /* Information about template unification failures. These are the
457 parameters passed to fn_type_unification. */
459 tree tmpl;
460 tree explicit_targs;
464 tree return_type;
465 unification_kind_t strict;
468 /* Information about template instantiation failures. These are the
469 parameters passed to instantiate_template. */
471 tree tmpl;
472 tree targs;
475 };
478 /* The FUNCTION_DECL that will be called if this candidate is
479 selected by overload resolution. */
480 tree fn;
481 /* If not NULL_TREE, the first argument to use when calling this
482 function. */
483 tree first_arg;
484 /* The rest of the arguments to use when calling this function. If
485 there are no further arguments this may be NULL or it may be an
486 empty vector. */
488 /* The implicit conversion sequences for each of the arguments to
489 FN. */
491 /* The number of implicit conversion sequences. */
493 /* If FN is a user-defined conversion, the standard conversion
494 sequence from the type returned by FN to the desired destination
495 type. */
498 /* If FN is a member function, the binfo indicating the path used to
499 qualify the name of FN at the call site. This path is used to
500 determine whether or not FN is accessible if it is selected by
501 overload resolution. The DECL_CONTEXT of FN will always be a
502 (possibly improper) base of this binfo. */
503 tree access_path;
504 /* If FN is a non-static member function, the binfo indicating the
505 subobject to which the `this' pointer should be converted if FN
506 is selected by overload resolution. The type pointed to by
507 the `this' pointer must correspond to the most derived class
508 indicated by the CONVERSION_PATH. */
509 tree conversion_path;
510 tree template_decl;
511 tree explicit_targs;
516 /* The flags active in add_candidate. */
518 };
520 /* Returns true iff T is a null pointer constant in the sense of
521 [conv.ptr]. */
523 bool
525 {
528 /* [conv.ptr]
530 A null pointer constant is an integral constant expression
531 (_expr.const_) rvalue of integer type that evaluates to zero or
532 an rvalue of type std::nullptr_t. */
537 {
540 /* Core issue 903 says only literal 0 is a null pointer constant. */
547 }
549 {
554 }
557 }
559 /* Returns true iff T is a null member pointer value (4.11). */
561 bool
563 {
572 else
574 }
576 /* Returns nonzero if PARMLIST consists of only default parms,
577 ellipsis, and/or undeduced parameter packs. */
579 bool
581 {
588 }
590 /* Allocate N bytes of memory from the conversion obstack. The memory
591 is zeroed before being returned. */
595 {
598 {
601 }
605 }
607 /* Allocate rejection reasons. */
611 {
616 }
620 {
626 }
630 {
637 }
641 {
648 }
652 {
658 }
662 {
668 }
675 {
682 /* Copy args to our own storage. */
690 }
694 {
696 }
700 {
703 }
707 {
710 }
712 // Build a constraint failure record, saving information into the
713 // template_instantiation field of the rejection. If FN is not a template
714 // declaration, the TMPL member is the FN declaration and TARGS is empty.
718 {
721 {
724 }
725 else
726 {
729 }
731 }
733 /* Dynamically allocate a conversion. */
737 {
742 }
744 /* Make sure that all memory on the conversion obstack has been
745 freed. */
747 void
749 {
753 }
755 /* Dynamically allocate an array of N conversions. */
759 {
761 }
765 {
769 /* Note that the caller is responsible for filling in t->cand for
770 user-defined conversions. */
776 {
793 }
799 }
801 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
802 specialization of std::initializer_list<T>, if such a conversion is
803 possible. */
807 {
813 tree val;
815 /* Within a list-initialization we can have more user-defined
816 conversions. */
818 /* But no narrowing conversions. */
821 /* Can't make an array of these types. */
828 {
829 conversion *sub
836 }
844 {
852 }
855 }
857 /* Return the next conversion of the conversion chain (if applicable),
858 or NULL otherwise. Please use this function instead of directly
859 accessing fields of struct conversion. */
863 {
870 }
872 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
873 is a valid aggregate initializer for array type ATYPE. */
875 static bool
877 {
881 {
887 else
889 complain);
892 }
894 }
896 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
897 aggregate class, if such a conversion is possible. */
901 {
907 /* We already called reshape_init in implicit_conversion. */
909 /* The conversions within the init-list aren't affected by the enclosing
910 context; they're always simple copy-initialization. */
914 {
916 tree val;
924 /* Value-initialization of reference is ill-formed. */
926 else
927 {
931 }
937 else
939 complain);
946 }
958 }
960 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
961 array type, if such a conversion is possible. */
965 {
970 tree val;
975 /* We might need to propagate the size from the element to the array. */
980 {
984 }
989 {
990 conversion *sub
1002 }
1011 }
1013 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1014 complex type, if such a conversion is possible. */
1018 tsubst_flags_t complain)
1019 {
1024 tree val;
1035 {
1036 conversion *sub
1048 }
1057 }
1059 /* Build a representation of the identity conversion from EXPR to
1060 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1064 {
1072 }
1074 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1075 were multiple user-defined conversions to accomplish the job.
1076 Build a conversion that indicates that ambiguity. */
1080 {
1088 }
1090 tree
1092 {
1096 }
1098 /* Returns the standard conversion path (see [conv]) from type FROM to type
1099 TO, if any. For proper handling of null pointer constants, you must
1100 also pass the expression EXPR to convert from. If C_CAST_P is true,
1101 this conversion is coming from a C-style cast. */
1106 {
1110 tree qualified_to;
1114 {
1117 }
1123 {
1125 {
1131 }
1133 {
1134 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1137 }
1138 }
1145 {
1148 /* Tell convert_like_real that we're using the address. */
1151 }
1152 /* Wrapping a ck_rvalue around a class prvalue (as a result of using
1153 obvalue_p) seems odd, since it's already a prvalue, but that's how we
1154 express the copy constructor call required by copy-initialization. */
1156 {
1158 {
1159 tree bitfield_type;
1162 {
1165 }
1166 }
1169 /* Tell convert_like_real to set LOOKUP_PREFER_RVALUE. */
1171 }
1173 /* Allow conversion between `__complex__' data types. */
1175 {
1176 /* The standard conversion sequence to convert FROM to TO is
1177 the standard conversion sequence to perform componentwise
1178 conversion. */
1181 complain);
1184 {
1187 }
1188 else
1192 }
1195 {
1199 }
1201 /* [conv.ptr]
1202 A null pointer constant can be converted to a pointer type; ... A
1203 null pointer constant of integral type can be converted to an
1204 rvalue of type std::nullptr_t. */
1212 {
1213 /* For backwards brain damage compatibility, allow interconversion of
1214 pointers and integers with a pedwarn. */
1217 }
1219 {
1220 /* For backwards brain damage compatibility, allow interconversion of
1221 enums and integers with a pedwarn. */
1224 }
1227 {
1228 tree to_pointee;
1229 tree from_pointee;
1232 {
1236 /* Since this is the target of a pointer, it can't have function
1237 qualifiers, so any TYPE_QUALS must be for attributes const or
1238 noreturn. Strip them. */
1245 }
1246 else
1247 {
1250 }
1254 to_pointee))
1255 ;
1259 {
1261 /* Don't try to apply restrict to void. */
1266 }
1268 {
1275 && (same_type_ignoring_top_level_qualifiers_p
1277 {
1280 }
1281 else
1283 }
1286 /* [conv.ptr]
1288 An rvalue of type "pointer to cv D," where D is a
1289 class type, can be converted to an rvalue of type
1290 "pointer to cv B," where B is a base class (clause
1291 _class.derived_) of D. If B is an inaccessible
1292 (clause _class.access_) or ambiguous
1293 (_class.member.lookup_) base class of D, a program
1294 that necessitates this conversion is ill-formed.
1295 Therefore, we use DERIVED_FROM_P, and do not check
1296 access or uniqueness. */
1298 {
1299 from_pointee
1305 }
1310 /* In a C-style cast, we ignore CV-qualification because we
1311 are allowed to perform a static_cast followed by a
1312 const_cast. */
1317 /* converting from string constant to char *. */
1321 /* Allow conversions among compatible ObjC pointer types (base
1322 conversions have been already handled above). */
1327 {
1330 }
1331 else
1335 }
1337 {
1351 else
1355 {
1357 tbase,
1363 }
1366 }
1368 {
1369 /* [conv.bool]
1371 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1372 to member type can be converted to a prvalue of type bool. ...
1373 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1374 std::nullptr_t can be converted to a prvalue of type bool; */
1380 {
1391 }
1394 }
1395 /* We don't check for ENUMERAL_TYPE here because there are no standard
1396 conversions to enum type. */
1397 /* As an extension, allow conversion to complex type. */
1399 {
1406 /* Give this a better rank if it's a promotion. */
1410 }
1416 {
1420 /* The derived-to-base conversion indicates the initialization
1421 of a parameter with base type from an object of a derived
1422 type. A temporary object is created to hold the result of
1423 the conversion unless we're binding directly to a reference. */
1425 }
1426 else
1433 }
1435 /* Returns nonzero if T1 is reference-related to T2. */
1437 bool
1439 {
1446 /* [dcl.init.ref]
1448 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1449 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1450 of T2. */
1454 }
1456 /* Returns nonzero if T1 is reference-compatible with T2. */
1458 static bool
1460 {
1461 /* [dcl.init.ref]
1463 "cv1 T1" is reference compatible with "cv2 T2" if
1464 * T1 is reference-related to T2 or
1465 * T2 is "noexcept function" and T1 is "function", where the
1466 function types are otherwise the same,
1467 and cv1 is the same cv-qualification as, or greater cv-qualification
1468 than, cv2. */
1472 }
1474 /* A reference of the indicated TYPE is being bound directly to the
1475 expression represented by the implicit conversion sequence CONV.
1476 Return a conversion sequence for this binding. */
1480 {
1481 tree t;
1489 /* Mark the identity conv as to not decay to rvalue. */
1492 /* [over.ics.rank]
1494 When a parameter of reference type binds directly
1495 (_dcl.init.ref_) to an argument expression, the implicit
1496 conversion sequence is the identity conversion, unless the
1497 argument expression has a type that is a derived class of the
1498 parameter type, in which case the implicit conversion sequence is
1499 a derived-to-base Conversion.
1501 If the parameter binds directly to the result of applying a
1502 conversion function to the argument expression, the implicit
1503 conversion sequence is a user-defined conversion sequence
1504 (_over.ics.user_), with the second standard conversion sequence
1505 either an identity conversion or, if the conversion function
1506 returns an entity of a type that is a derived class of the
1507 parameter type, a derived-to-base conversion. */
1509 {
1510 /* Represent the derived-to-base conversion. */
1512 /* We will actually be binding to the base-class subobject in
1513 the derived class, so we mark this conversion appropriately.
1514 That way, convert_like knows not to generate a temporary. */
1516 }
1519 }
1521 /* Returns the conversion path from type FROM to reference type TO for
1522 purposes of reference binding. For lvalue binding, either pass a
1523 reference type to FROM or an lvalue expression to EXPR. If the
1524 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1525 the conversion returned. If C_CAST_P is true, this
1526 conversion is coming from a C-style cast. */
1530 tsubst_flags_t complain)
1531 {
1535 tree tfrom;
1538 cp_lvalue_kind gl_kind;
1542 {
1547 }
1550 {
1552 /* DR 1288: Otherwise, if the initializer list has a single element
1553 of type E and ... [T's] referenced type is reference-related to E,
1554 the object or reference is initialized from that element... */
1556 {
1562 {
1566 }
1567 }
1568 /* Otherwise, if T is a reference type, a prvalue temporary of the type
1569 referenced by T is copy-list-initialized, and the reference is bound
1570 to that temporary. */
1572 skip:;
1573 }
1576 {
1581 else
1583 }
1589 else
1592 /* Don't allow a class prvalue when LOOKUP_NO_TEMP_BIND. */
1597 /* Same mask as real_lvalue_p. */
1604 /* Figure out whether or not the types are reference-related and
1605 reference compatible. We have to do this after stripping
1606 references from FROM. */
1608 /* If this is a C cast, first convert to an appropriately qualified
1609 type, so that we can later do a const_cast to the desired type. */
1615 /* Directly bind reference when target expression's type is compatible with
1616 the reference and expression is an lvalue. In DR391, the wording in
1617 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1618 const and rvalue references to rvalues of compatible class type.
1619 We should also do direct bindings for non-class xvalues. */
1621 {
1622 /* [dcl.init.ref]
1624 If the initializer expression
1626 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1627 is reference-compatible with "cv2 T2,"
1629 the reference is bound directly to the initializer expression
1630 lvalue.
1632 [...]
1633 If the initializer expression is an rvalue, with T2 a class type,
1634 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1635 is bound to the object represented by the rvalue or to a sub-object
1636 within that object. */
1642 /* Handle rvalue reference to function properly. */
1643 conv->rvaluedness_matches_p
1645 else
1646 conv->rvaluedness_matches_p
1651 /* For the purposes of overload resolution, we ignore the fact
1652 this expression is a bitfield or packed field. (In particular,
1653 [over.ics.ref] says specifically that a function with a
1654 non-const reference parameter is viable even if the
1655 argument is a bitfield.)
1657 However, when we actually call the function we must create
1658 a temporary to which to bind the reference. If the
1659 reference is volatile, or isn't const, then we cannot make
1660 a temporary, so we just issue an error when the conversion
1661 actually occurs. */
1664 /* Don't allow binding of lvalues (other than function lvalues) to
1665 rvalue references. */
1670 /* Nor the reverse. */
1681 }
1682 /* [class.conv.fct] A conversion function is never used to convert a
1683 (possibly cv-qualified) object to the (possibly cv-qualified) same
1684 object type (or a reference to it), to a (possibly cv-qualified) base
1685 class of that type (or a reference to it).... */
1688 {
1689 /* [dcl.init.ref]
1691 If the initializer expression
1693 -- has a class type (i.e., T2 is a class type) can be
1694 implicitly converted to an lvalue of type "cv3 T3," where
1695 "cv1 T1" is reference-compatible with "cv3 T3". (this
1696 conversion is selected by enumerating the applicable
1697 conversion functions (_over.match.ref_) and choosing the
1698 best one through overload resolution. (_over.match_).
1700 the reference is bound to the lvalue result of the conversion
1701 in the second case. */
1703 complain);
1706 }
1708 /* From this point on, we conceptually need temporaries, even if we
1709 elide them. Only the cases above are "direct bindings". */
1713 /* [over.ics.rank]
1715 When a parameter of reference type is not bound directly to an
1716 argument expression, the conversion sequence is the one required
1717 to convert the argument expression to the underlying type of the
1718 reference according to _over.best.ics_. Conceptually, this
1719 conversion sequence corresponds to copy-initializing a temporary
1720 of the underlying type with the argument expression. Any
1721 difference in top-level cv-qualification is subsumed by the
1722 initialization itself and does not constitute a conversion. */
1724 /* [dcl.init.ref]
1726 Otherwise, the reference shall be an lvalue reference to a
1727 non-volatile const type, or the reference shall be an rvalue
1728 reference.
1730 We try below to treat this as a bad conversion to improve diagnostics,
1731 but if TO is an incomplete class, we need to reject this conversion
1732 now to avoid unnecessary instantiation. */
1737 /* We're generating a temporary now, but don't bind any more in the
1738 conversion (specifically, don't slice the temporary returned by a
1739 conversion operator). */
1742 /* Core issue 899: When [copy-]initializing a temporary to be bound
1743 to the first parameter of a copy constructor (12.8) called with
1744 a single argument in the context of direct-initialization,
1745 explicit conversion functions are also considered.
1747 So don't set LOOKUP_ONLYCONVERTING in that case. */
1758 {
1759 /* If initializing the temporary used a conversion function,
1760 recalculate the second conversion sequence. */
1764 {
1767 conversion *new_second
1773 }
1774 }
1777 /* This reference binding, unlike those above, requires the
1778 creation of a temporary. */
1782 /* [dcl.init.ref]
1784 Otherwise, the reference shall be an lvalue reference to a
1785 non-volatile const type, or the reference shall be an rvalue
1786 reference. */
1790 /* [dcl.init.ref]
1792 Otherwise, a temporary of type "cv1 T1" is created and
1793 initialized from the initializer expression using the rules for a
1794 non-reference copy initialization. If T1 is reference-related to
1795 T2, cv1 must be the same cv-qualification as, or greater
1796 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1801 }
1803 /* Returns the implicit conversion sequence (see [over.ics]) from type
1804 FROM to type TO. The optional expression EXPR may affect the
1805 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1806 true, this conversion is coming from a C-style cast. */
1811 {
1818 /* Other flags only apply to the primary function in overload
1819 resolution, or after we've chosen one. */
1824 /* FIXME: actually we don't want warnings either, but we can't just
1825 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1826 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1827 We really ought not to issue that warning until we've committed
1828 to that conversion. */
1831 /* Call reshape_init early to remove redundant braces. */
1836 {
1841 }
1845 else
1852 {
1856 /* As an extension, allow list-initialization of _Complex. */
1858 {
1862 }
1864 /* Allow conversion from an initializer-list with one element to a
1865 scalar type. */
1867 {
1869 tree elt;
1875 else
1881 {
1884 /* Too many levels of braces, i.e. '{{1}}'. */
1887 }
1888 }
1891 }
1897 {
1907 {
1911 {
1912 /* "If C is not an initializer-list constructor and the
1913 initializer list has a single element of type cv U, where U is
1914 X or a class derived from X, the implicit conversion sequence
1915 has Exact Match rank if U is X, or Conversion rank if U is
1916 derived from X." */
1922 }
1924 }
1926 /* We used to try to bind a reference to a temporary here, but that
1927 is now handled after the recursive call to this function at the end
1928 of reference_binding. */
1930 }
1933 }
1935 /* Like implicit_conversion, but return NULL if the conversion is bad.
1937 This is not static so that check_non_deducible_conversion can call it within
1938 add_template_candidate_real as part of overload resolution; it should not be
1939 called outside of overload resolution. */
1941 conversion *
1944 {
1950 }
1952 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1953 functions. ARGS will not be changed until a single candidate is
1954 selected. */
1963 {
1981 }
1983 /* Return the number of remaining arguments in the parameter list
1984 beginning with ARG. */
1986 int
1988 {
1993 n++;
1996 }
1998 /* [over.match.copy]: When initializing a temporary object (12.2) to be bound
1999 to the first parameter of a constructor where the parameter is of type
2000 "reference to possibly cv-qualified T" and the constructor is called with a
2001 single argument in the context of direct-initialization of an object of type
2002 "cv2 T", explicit conversion functions are also considered.
2004 So set LOOKUP_COPY_PARM to let reference_binding know that
2005 it's being called in that context. */
2007 int
2009 {
2011 tree t;
2014 && (same_type_ignoring_top_level_qualifiers_p
2016 {
2022 }
2023 else
2027 }
2029 /* Create an overload candidate for the function or method FN called
2030 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
2031 FLAGS is passed on to implicit_conversion.
2033 This does not change ARGS.
2035 CTYPE, if non-NULL, is the type we want to pretend this function
2036 comes from for purposes of overload resolution. */
2044 tsubst_flags_t complain)
2045 {
2048 tree parmnode;
2054 /* At this point we should not see any functions which haven't been
2055 explicitly declared, except for friend functions which will have
2056 been found using argument dependent lookup. */
2059 /* The `this', `in_chrg' and VTT arguments to constructors are not
2060 considered in overload resolution. */
2062 {
2064 /* Bring back parameters omitted from an inherited ctor. */
2066 else
2070 {
2073 }
2074 }
2075 else
2082 /* 13.3.2 - Viable functions [over.match.viable]
2083 First, to be a viable function, a candidate function shall have enough
2084 parameters to agree in number with the arguments in the list.
2086 We need to check this first; otherwise, checking the ICSes might cause
2087 us to produce an ill-formed template instantiation. */
2091 {
2095 }
2099 {
2103 }
2105 /* An inherited constructor (12.6.3 [class.inhctor.init]) that has a first
2106 parameter of type "reference to cv C" (including such a constructor
2107 instantiated from a template) is excluded from the set of candidate
2108 functions when used to construct an object of type D with an argument list
2109 containing a single argument if C is reference-related to D. */
2111 && flag_new_inheriting_ctors
2113 {
2119 {
2122 }
2123 }
2125 /* Second, for a function to be viable, its constraints must be
2126 satisfied. */
2129 {
2132 }
2134 /* When looking for a function from a subobject from an implicit
2135 copy/move constructor/operator=, don't consider anything that takes (a
2136 reference to) an unrelated type. See c++/44909 and core 1092. */
2138 {
2144 else
2147 {
2150 ctype))
2152 }
2154 /* This only applies at the top level. */
2156 }
2161 /* Third, for F to be a viable function, there shall exist for each
2162 argument an implicit conversion sequence that converts that argument
2163 to the corresponding parameter of F. */
2168 {
2170 tree arg;
2178 {
2179 /* Already set during deduction. */
2182 }
2186 else
2195 {
2200 /* The type of the implicit object parameter ('this') for
2201 overload resolution is not always the same as for the
2202 function itself; conversion functions are considered to
2203 be members of the class being converted, and functions
2204 introduced by a using-declaration are considered to be
2205 members of the class that uses them.
2207 Since build_over_call ignores the ICS for the `this'
2208 parameter, we can just change the parm type. */
2210 {
2211 parmtype = cp_build_qualified_type
2214 {
2215 /* If the function has a ref-qualifier, the implicit
2216 object parameter has reference type. */
2219 /* The special handling of 'this' conversions in compare_ics
2220 does not apply if there is a ref-qualifier. */
2222 }
2223 else
2224 {
2226 /* We don't use build_this here because we don't want to
2227 capture the object argument until we've chosen a
2228 non-static member function. */
2231 }
2232 }
2239 }
2240 else
2241 {
2245 }
2252 {
2256 }
2259 {
2262 }
2263 }
2265 out:
2268 }
2270 /* Create an overload candidate for the conversion function FN which will
2271 be invoked for expression OBJ, producing a pointer-to-function which
2272 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2273 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2274 passed on to implicit_conversion.
2276 Actually, we don't really care about FN; we care about the type it
2277 converts to. There may be multiple conversion functions that will
2278 convert to that type, and we rely on build_user_type_conversion_1 to
2279 choose the best one; so when we create our candidate, we record the type
2280 instead of the function. */
2286 tsubst_flags_t complain)
2287 {
2305 /* Don't bother looking up the same type twice. */
2310 {
2316 else
2321 {
2324 /* Leave the 'cand' field null; we'll figure out the conversion in
2325 convert_like_real if this candidate is chosen. */
2327 }
2331 {
2335 }
2336 else
2337 {
2341 }
2348 {
2351 }
2358 }
2362 {
2366 }
2370 }
2372 static void
2376 {
2390 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2391 conversion ops are allowed. We handle that here by just checking for
2392 boolean_type_node because other operators don't ask for it. COND_EXPR
2393 also does contextual conversion to bool for the first operand, but we
2394 handle that in build_conditional_expr, and type1 here is operand 2. */
2399 {
2406 {
2408 /* We need something for printing the candidate. */
2412 }
2414 {
2418 }
2420 }
2422 /* For COND_EXPR we rearranged the arguments; undo that now. */
2424 {
2429 complain);
2432 else
2433 {
2436 boolean_type_node);
2437 }
2438 }
2445 }
2447 static bool
2449 {
2451 }
2453 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2455 static bool
2457 {
2458 /* [over.built]
2460 In this section, the term promoted integral type is used to refer
2461 to those integral types which are preserved by integral promotion
2462 (including e.g. int and long but excluding e.g. char).
2463 Similarly, the term promoted arithmetic type refers to promoted
2464 integral types plus floating types. */
2468 }
2470 /* Create any builtin operator overload candidates for the operator in
2471 question given the converted operand types TYPE1 and TYPE2. The other
2472 args are passed through from add_builtin_candidates to
2473 build_builtin_candidate.
2475 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2476 If CODE is requires candidates operands of the same type of the kind
2477 of which TYPE1 and TYPE2 are, we add both candidates
2478 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2480 static void
2484 tsubst_flags_t complain)
2485 {
2487 {
2495 }
2498 {
2500 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2501 and VQ is either volatile or empty, there exist candidate operator
2502 functions of the form
2503 VQ T& operator++(VQ T&);
2504 T operator++(VQ T&, int);
2505 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2506 type other than bool, and VQ is either volatile or empty, there exist
2507 candidate operator functions of the form
2508 VQ T& operator--(VQ T&);
2509 T operator--(VQ T&, int);
2510 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2511 complete object type, and VQ is either volatile or empty, there exist
2512 candidate operator functions of the form
2513 T*VQ& operator++(T*VQ&);
2514 T*VQ& operator--(T*VQ&);
2515 T* operator++(T*VQ&, int);
2516 T* operator--(T*VQ&, int); */
2522 /* FALLTHRU */
2526 {
2529 }
2532 /* 7 For every cv-qualified or cv-unqualified object type T, there
2533 exist candidate operator functions of the form
2535 T& operator*(T*);
2537 8 For every function type T, there exist candidate operator functions of
2538 the form
2539 T& operator*(T*); */
2548 /* 9 For every type T, there exist candidate operator functions of the form
2549 T* operator+(T*);
2551 10For every promoted arithmetic type T, there exist candidate operator
2552 functions of the form
2553 T operator+(T);
2554 T operator-(T); */
2559 /* FALLTHRU */
2565 /* 11For every promoted integral type T, there exist candidate operator
2566 functions of the form
2567 T operator~(T); */
2574 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2575 is the same type as C2 or is a derived class of C2, T is a complete
2576 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2577 there exist candidate operator functions of the form
2578 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2579 where CV12 is the union of CV1 and CV2. */
2583 {
2591 }
2594 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2595 didate operator functions of the form
2596 LR operator*(L, R);
2597 LR operator/(L, R);
2598 LR operator+(L, R);
2599 LR operator-(L, R);
2600 bool operator<(L, R);
2601 bool operator>(L, R);
2602 bool operator<=(L, R);
2603 bool operator>=(L, R);
2604 bool operator==(L, R);
2605 bool operator!=(L, R);
2606 where LR is the result of the usual arithmetic conversions between
2607 types L and R.
2609 14For every pair of types T and I, where T is a cv-qualified or cv-
2610 unqualified complete object type and I is a promoted integral type,
2611 there exist candidate operator functions of the form
2612 T* operator+(T*, I);
2613 T& operator[](T*, I);
2614 T* operator-(T*, I);
2615 T* operator+(I, T*);
2616 T& operator[](I, T*);
2618 15For every T, where T is a pointer to complete object type, there exist
2619 candidate operator functions of the form112)
2620 ptrdiff_t operator-(T, T);
2622 16For every pointer or enumeration type T, there exist candidate operator
2623 functions of the form
2624 bool operator<(T, T);
2625 bool operator>(T, T);
2626 bool operator<=(T, T);
2627 bool operator>=(T, T);
2628 bool operator==(T, T);
2629 bool operator!=(T, T);
2631 17For every pointer to member type T, there exist candidate operator
2632 functions of the form
2633 bool operator==(T, T);
2634 bool operator!=(T, T); */
2641 {
2644 }
2645 /* FALLTHRU */
2658 {
2661 }
2663 {
2666 }
2667 /* Fall through. */
2683 {
2686 }
2689 {
2692 }
2698 /* FALLTHRU */
2701 {
2704 }
2706 {
2709 }
2712 /* 18For every pair of promoted integral types L and R, there exist candi-
2713 date operator functions of the form
2714 LR operator%(L, R);
2715 LR operator&(L, R);
2716 LR operator^(L, R);
2717 LR operator|(L, R);
2718 L operator<<(L, R);
2719 L operator>>(L, R);
2720 where LR is the result of the usual arithmetic conversions between
2721 types L and R. */
2729 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2733 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2734 type, VQ is either volatile or empty, and R is a promoted arithmetic
2735 type, there exist candidate operator functions of the form
2736 VQ L& operator=(VQ L&, R);
2737 VQ L& operator*=(VQ L&, R);
2738 VQ L& operator/=(VQ L&, R);
2739 VQ L& operator+=(VQ L&, R);
2740 VQ L& operator-=(VQ L&, R);
2742 20For every pair T, VQ), where T is any type and VQ is either volatile
2743 or empty, there exist candidate operator functions of the form
2744 T*VQ& operator=(T*VQ&, T*);
2746 21For every pair T, VQ), where T is a pointer to member type and VQ is
2747 either volatile or empty, there exist candidate operator functions of
2748 the form
2749 VQ T& operator=(VQ T&, T);
2751 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2752 unqualified complete object type, VQ is either volatile or empty, and
2753 I is a promoted integral type, there exist candidate operator func-
2754 tions of the form
2755 T*VQ& operator+=(T*VQ&, I);
2756 T*VQ& operator-=(T*VQ&, I);
2758 23For every triple L, VQ, R), where L is an integral or enumeration
2759 type, VQ is either volatile or empty, and R is a promoted integral
2760 type, there exist candidate operator functions of the form
2762 VQ L& operator%=(VQ L&, R);
2763 VQ L& operator<<=(VQ L&, R);
2764 VQ L& operator>>=(VQ L&, R);
2765 VQ L& operator&=(VQ L&, R);
2766 VQ L& operator^=(VQ L&, R);
2767 VQ L& operator|=(VQ L&, R); */
2771 {
2775 {
2778 }
2779 /* FALLTHRU */
2792 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2805 {
2808 }
2813 }
2818 /* [over.built]
2820 For every pair of promoted arithmetic types L and R, there
2821 exist candidate operator functions of the form
2823 LR operator?(bool, L, R);
2825 where LR is the result of the usual arithmetic conversions
2826 between types L and R.
2828 For every type T, where T is a pointer or pointer-to-member
2829 type, there exist candidate operator functions of the form T
2830 operator?(bool, T, T); */
2834 /* That's OK. */
2837 /* Otherwise, the types should be pointers. */
2841 /* We don't check that the two types are the same; the logic
2842 below will actually create two candidates; one in which both
2843 parameter types are TYPE1, and one in which both parameter
2844 types are TYPE2. */
2855 }
2857 /* Make sure we don't create builtin candidates with dependent types. */
2861 {
2862 /* Try to recover if one of the types is non-dependent. But if
2863 there's only one type, there's nothing we can do. */
2866 /* And we lose if both are dependent. */
2869 /* Or if they have different forms. */
2877 }
2879 /* If we're dealing with two pointer types or two enumeral types,
2880 we need candidates for both of them. */
2889 {
2891 {
2893 error_mark_node,
2894 error_mark_node,
2895 CPO_CONVERSION,
2896 tf_none);
2898 {
2899 build_builtin_candidate
2903 }
2904 }
2906 build_builtin_candidate
2908 build_builtin_candidate
2911 }
2913 build_builtin_candidate
2915 }
2917 tree
2919 {
2925 }
2927 /* There are three conditions of builtin candidates:
2929 1) bool-taking candidates. These are the same regardless of the input.
2930 2) pointer-pair taking candidates. These are generated for each type
2931 one of the input types converts to.
2932 3) arithmetic candidates. According to the standard, we should generate
2933 all of these, but I'm trying not to...
2935 Here we generate a superset of the possible candidates for this particular
2936 case. That is a subset of the full set the standard defines, plus some
2937 other cases which the standard disallows. add_builtin_candidate will
2938 filter out the invalid set. */
2940 static void
2944 {
2948 /* TYPES[i] is the set of possible builtin-operator parameter types
2949 we will consider for the Ith argument. */
2954 {
2957 else
2959 }
2962 {
2963 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2964 and VQ is either volatile or empty, there exist candidate operator
2965 functions of the form
2966 VQ T& operator++(VQ T&); */
2976 /* 24There also exist candidate operator functions of the form
2977 bool operator!(bool);
2978 bool operator&&(bool, bool);
2979 bool operator||(bool, bool); */
2982 build_builtin_candidate
2989 build_builtin_candidate
3007 /* Fall through. */
3011 }
3017 {
3019 ;
3021 {
3022 tree convs;
3030 {
3035 }
3041 {
3054 {
3060 }
3064 }
3065 }
3066 else
3067 {
3072 {
3078 }
3080 }
3081 }
3083 /* Run through the possible parameter types of both arguments,
3084 creating candidates with those parameter types. */
3086 {
3088 tree u;
3092 add_builtin_candidate
3095 else
3096 add_builtin_candidate
3099 }
3103 }
3106 /* If TMPL can be successfully instantiated as indicated by
3107 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
3109 TMPL is the template. EXPLICIT_TARGS are any explicit template
3110 arguments. ARGLIST is the arguments provided at the call-site.
3111 This does not change ARGLIST. The RETURN_TYPE is the desired type
3112 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
3113 as for add_function_candidate. If an OBJ is supplied, FLAGS and
3114 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3122 tsubst_flags_t complain)
3123 {
3133 tree arg;
3135 tree fn;
3140 /* We don't do deduction on the in-charge parameter, the VTT
3141 parameter or 'this'. */
3143 {
3147 /* We're deducing for a call to the result of a template conversion
3149 else
3151 }
3156 {
3159 else
3161 }
3169 {
3170 /* 12.8/6 says, "A declaration of a constructor for a class X is
3171 ill-formed if its first parameter is of type (optionally cv-qualified)
3172 X and either there are no other parameters or else all other
3173 parameters have default arguments. A member function template is never
3174 instantiated to produce such a constructor signature."
3176 So if we're trying to copy an object of the containing class, don't
3177 consider a template constructor that has a first parameter type that
3178 is just a template parameter, as we would deduce a signature that we
3179 would then reject in the code below. */
3181 {
3186 {
3190 }
3191 }
3192 }
3199 {
3202 }
3206 {
3209 }
3216 args_without_in_chrg,
3217 nargs_without_in_chrg,
3222 {
3223 /* Don't repeat unification later if it already resulted in errors. */
3227 nargs_without_in_chrg,
3229 else
3232 }
3235 {
3238 ctype))
3239 {
3240 /* We're trying to produce a constructor with a prohibited signature,
3241 as discussed above; handle here any cases we didn't catch then,
3242 such as X(X<T>). */
3245 }
3246 }
3249 /* Aha, this is a conversion function. */
3252 else
3257 /* This situation can occur if a member template of a template
3258 class is specialized. Then, instantiate_template might return
3259 an instantiation of the specialization, in which case the
3260 DECL_TI_TEMPLATE field will point at the original
3261 specialization. For example:
3263 template <class T> struct S { template <class U> void f(U);
3264 template <> void f(int) {}; };
3265 S<double> sd;
3266 sd.f(3);
3268 Here, TMPL will be template <class U> S<double>::f(U).
3269 And, instantiate template will give us the specialization
3270 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3271 for this will point at template <class T> template <> S<T>::f(int),
3272 so that we can find the definition. For the purposes of
3273 overload resolution, however, we want the original TMPL. */
3275 else
3280 fail:
3283 }
3292 {
3293 return
3298 }
3300 /* Create an overload candidate for the conversion function template TMPL,
3301 returning RETURN_TYPE, which will be invoked for expression OBJ to produce a
3302 pointer-to-function which will in turn be called with the argument list
3303 ARGLIST, and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
3304 passed on to implicit_conversion. */
3308 tree obj,
3312 {
3313 /* Making this work broke PR 71117 and 85118, so until the committee resolves
3314 core issue 2189, let's disable this candidate if there are any call
3315 operators. */
3319 return
3323 complain);
3324 }
3326 /* The CANDS are the set of candidates that were considered for
3327 overload resolution. Return the set of viable candidates, or CANDS
3328 if none are viable. If any of the candidates were viable, set
3329 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3330 considered viable only if it is strictly viable. */
3336 {
3342 /* Be strict inside templates, since build_over_call won't actually
3343 do the conversions to get pedwarns. */
3353 {
3357 {
3358 /* Be strict in the presence of a viable candidate. Also if
3359 there are template candidates, so that we get deduction errors
3360 for them instead of silently preferring a bad conversion. */
3363 {
3364 /* Put any spliced near matches back onto the main list so
3365 that we see them if there is no strict match. */
3371 }
3372 }
3375 {
3383 }
3384 else
3386 }
3389 }
3391 static bool
3393 {
3398 }
3400 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3401 words, it is about to become the "this" pointer for a member
3402 function call. Take the address of the object. */
3404 static tree
3406 {
3407 /* In a template, we are only concerned about the type of the
3408 expression, so we can take a shortcut. */
3413 }
3415 /* Returns true iff functions are equivalent. Equivalent functions are
3416 not '==' only if one is a function-local extern function or if
3417 both are extern "C". */
3421 {
3430 }
3432 /* Print information about a candidate being rejected due to INFO. */
3434 static void
3436 {
3441 {
3442 /* Conversion of implicit `this' argument failed. */
3444 /* A bad conversion for 'this' must be discarding cv-quals. */
3447 from);
3448 else
3452 }
3454 {
3459 tf_warning_or_error);
3460 }
3462 /* Conversion of conversion function return value failed. */
3465 else
3468 }
3470 /* Print information about a candidate with WANT parameters and we found
3471 HAVE. */
3473 static void
3475 {
3480 }
3482 /* Print information about one overload candidate CANDIDATE. MSGSTR
3483 is the text to print before the candidate itself.
3485 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3486 to have been run through gettext by the caller. This wart makes
3487 life simpler in print_z_candidates and for the translators. */
3489 static void
3492 {
3502 {
3513 else
3516 }
3523 else
3526 {
3529 }
3530 /* Give the user some information about why this candidate failed. */
3532 {
3536 {
3549 "cannot be converted to %qT with a qualification "
3555 "conversion function specialization to %qT is not an "
3560 /* We use template_unification_error_rejection if unification caused
3561 actual non-SFINAE errors, in which case we don't need to repeat
3562 them here. */
3564 {
3568 }
3569 /* Re-run template unification with diagnostics. */
3573 (make_tree_vec
3584 " a constructor taking a single argument of its own "
3588 {
3592 }
3596 "initialization from an expression of the same or derived "
3601 /* This candidate didn't have any issues or we failed to
3602 handle a particular code. Either way... */
3604 }
3605 }
3606 }
3608 static void
3610 {
3617 /* Remove non-viable deleted candidates. */
3620 {
3625 else
3627 }
3628 /* ...if there are any non-deleted ones. */
3632 /* There may be duplicates in the set of candidates. We put off
3633 checking this condition as long as possible, since we have no way
3634 to eliminate duplicates from a set of functions in less than n^2
3635 time. Now we are about to emit an error message, so it is more
3636 permissible to go slowly. */
3638 {
3640 /* Skip builtin candidates and conversion functions. */
3645 {
3649 else
3651 }
3652 }
3656 }
3658 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3659 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3660 the result of the conversion function to convert it to the final
3661 desired type. Merge the two sequences into a single sequence,
3662 and return the merged sequence. */
3666 {
3672 /* Find the end of the second conversion sequence. */
3674 {
3675 /* The entire sequence is a user-conversion sequence. */
3679 }
3682 /* We're binding a reference directly to the result of the conversion.
3683 build_user_type_conversion_1 stripped the REFERENCE_TYPE from the return
3684 type, but we want it back. */
3687 /* Replace the identity conversion with the user conversion
3688 sequence. */
3692 }
3694 /* Handle overload resolution for initializing an object of class type from
3695 an initializer list. First we look for a suitable constructor that
3696 takes a std::initializer_list; if we don't find one, we then look for a
3697 non-list constructor.
3699 Parameters are as for add_candidates, except that the arguments are in
3700 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3701 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3703 static void
3710 tsubst_flags_t complain)
3711 {
3714 /* We're looking for a ctor for list-initialization. */
3716 /* And we don't allow narrowing conversions. We also use this flag to
3717 avoid the copy constructor call for copy-list-initialization. */
3723 /* Always use the default constructor if the list is empty (DR 990). */
3726 ;
3727 /* If the class has a list ctor, try passing the list as a single
3728 argument first, but only consider list ctors. */
3730 {
3737 }
3739 /* Expand the CONSTRUCTOR into a new argument vec. */
3747 /* We aren't looking for list-ctors anymore. */
3749 /* We allow more user-defined conversions within an init-list. */
3755 }
3757 /* Returns the best overload candidate to perform the requested
3758 conversion. This function is used for three the overloading situations
3759 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3760 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3761 per [dcl.init.ref], so we ignore temporary bindings. */
3765 tsubst_flags_t complain)
3766 {
3768 tree fromtype;
3782 /* We represent conversion within a hierarchy using RVALUE_CONV and
3783 BASE_CONV, as specified by [over.best.ics]; these become plain
3784 constructor calls, as specified in [dcl.init]. */
3789 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3790 creating a garbage BASELINK; constructors can't be inherited. */
3794 {
3799 {
3800 /* [class.conv.fct] A conversion function is never used to
3801 convert a (possibly cv-qualified) object to the (possibly
3802 cv-qualified) same object type (or a reference to it), to a
3803 (possibly cv-qualified) base class of that type (or a
3804 reference to it)... */
3805 }
3806 else
3808 }
3815 /* It's OK to bind a temporary for converting constructor arguments, but
3816 not in converting the return value of a conversion operator. */
3822 {
3827 /* We should never try to call the abstract or base constructor
3828 from here. */
3834 {
3835 /* List-initialization. */
3839 }
3840 else
3841 {
3845 }
3848 {
3851 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3852 set, then this is copy-initialization. In that case, "The
3853 result of the call is then used to direct-initialize the
3854 object that is the destination of the copy-initialization."
3855 [dcl.init]
3857 We represent this in the conversion sequence with an
3858 rvalue conversion, which means a constructor call. */
3861 cand->second_conv
3863 }
3864 }
3867 {
3870 else
3872 }
3875 {
3879 /* If we are called to convert to a reference type, we are trying to
3880 find a direct binding, so don't even consider temporaries. If
3881 we don't find a direct binding, the caller will try again to
3882 look for a temporary binding. */
3893 {
3895 conversion *ics
3897 rettype,
3900 complain);
3902 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3903 copy-initialization. In that case, "The result of the
3904 call is then used to direct-initialize the object that is
3905 the destination of the copy-initialization." [dcl.init]
3907 We represent this in the conversion sequence with an
3908 rvalue conversion, which means a constructor call. But
3909 don't add a second rvalue conversion if there's already
3910 one there. Which there really shouldn't be, but it's
3911 harmless since we'd add it here anyway. */
3919 {
3923 }
3926 {
3927 /* 13.3.1.5: For direct-initialization, those explicit
3928 conversion functions that are not hidden within S and
3929 yield type T or a type that can be converted to type T
3930 with a qualification conversion (4.4) are also candidate
3931 functions. */
3932 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3933 I've raised this issue with the committee. --jason 9/2011 */
3936 }
3938 {
3940 cand->reason
3943 }
3946 {
3947 /* 13.3.3.1.2: If the user-defined conversion is specified by
3948 a specialization of a conversion function template, the
3949 second standard conversion sequence shall have exact match
3950 rank. */
3953 }
3954 }
3955 }
3959 {
3963 }
3967 {
3969 {
3973 }
3982 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3983 ambiguous conversion is no worse than another user-defined
3984 conversion. */
3987 }
3989 tree convtype;
3993 /* DR 5: [in the first step of copy-initialization]...if the function
3994 is a constructor, the call initializes a temporary of the
3995 cv-unqualified version of the destination type. */
3997 else
3999 /* Build the user conversion sequence. */
4000 conv = build_conv
4002 convtype,
4008 /* Remember that this was a list-initialization. */
4012 /* Combine it with the second conversion sequence. */
4017 }
4019 /* Wrapper for above. */
4021 tree
4023 tsubst_flags_t complain)
4024 {
4026 tree ret;
4032 {
4035 else
4036 {
4039 }
4040 }
4041 else
4046 }
4048 /* Subroutine of convert_nontype_argument.
4050 EXPR is an expression used in a context that requires a converted
4051 constant-expression, such as a template non-type parameter. Do any
4052 necessary conversions (that are permitted for converted
4053 constant-expressions) to convert it to the desired type.
4055 If conversion is successful, returns the converted expression;
4056 otherwise, returns error_mark_node. */
4058 tree
4060 {
4063 tree t;
4069 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4076 /* A converted constant expression of type T is an expression, implicitly
4077 converted to type T, where the converted expression is a constant
4078 expression and the implicit conversion sequence contains only
4080 * user-defined conversions,
4081 * lvalue-to-rvalue conversions (7.1),
4082 * array-to-pointer conversions (7.2),
4083 * function-to-pointer conversions (7.3),
4084 * qualification conversions (7.5),
4085 * integral promotions (7.6),
4086 * integral conversions (7.8) other than narrowing conversions (11.6.4),
4087 * null pointer conversions (7.11) from std::nullptr_t,
4088 * null member pointer conversions (7.12) from std::nullptr_t, and
4089 * function pointer conversions (7.13),
4091 and where the reference binding (if any) binds directly. */
4096 {
4098 {
4099 /* A conversion function is OK. If it isn't constexpr, we'll
4100 complain later that the argument isn't constant. */
4102 /* The lvalue-to-rvalue conversion is OK. */
4104 /* Array-to-pointer and function-to-pointer. */
4106 /* Function pointer conversions. */
4108 /* Qualification conversions. */
4114 {
4120 }
4130 /* Integral promotion or conversion. */
4133 /* Conversion from nullptr to pointer or pointer-to-member. */
4139 /* fall through. */
4144 }
4145 }
4147 /* Avoid confusing convert_nontype_argument by introducing
4148 a redundant conversion to the same reference type. */
4151 {
4155 }
4158 {
4162 }
4163 else
4164 {
4169 }
4171 /* Free all the conversions we allocated. */
4175 }
4177 /* Do any initial processing on the arguments to a function call. */
4181 {
4183 tree arg;
4186 {
4190 {
4194 }
4197 }
4199 }
4201 /* Perform overload resolution on FN, which is called with the ARGS.
4203 Return the candidate function selected by overload resolution, or
4204 NULL if the event that overload resolution failed. In the case
4205 that overload resolution fails, *CANDIDATES will be the set of
4206 candidates considered, and ANY_VIABLE_P will be set to true or
4207 false to indicate whether or not any of the candidates were
4208 viable.
4210 The ARGS should already have gone through RESOLVE_ARGS before this
4211 function is called. */
4218 {
4220 tree explicit_targs;
4231 /* Check FN. */
4238 {
4242 }
4244 /* Add the various candidate functions. */
4249 LOOKUP_NORMAL,
4255 else
4260 }
4262 /* Print an error message about being unable to build a call to FN with
4263 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4264 be located; CANDIDATES is a possibly empty list of such
4265 functions. */
4267 static void
4270 {
4273 {
4276 }
4285 else
4290 }
4292 /* Return an expression for a call to FN (a namespace-scope function,
4293 or a static member function) with the ARGS. This may change
4294 ARGS. */
4296 tree
4298 tsubst_flags_t complain)
4299 {
4303 tree result;
4306 {
4310 }
4315 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4319 complain);
4322 {
4324 {
4325 // If there is a single (non-viable) function candidate,
4326 // let the error be diagnosed by cp_build_function_call_vec.
4331 // Otherwise, emit notes for non-viable candidates.
4333 }
4335 }
4336 else
4337 {
4339 /* If fn is template_id_expr, the call has explicit template arguments
4340 (e.g. func<int>(5)), communicate this info to build_over_call
4341 through flags so that later we can use it to decide whether to warn
4342 about peculiar null pointer conversion. */
4344 {
4345 /* If overload resolution selects a specialization of a
4346 function concept for non-dependent template arguments,
4347 the expression is true if the constraints are satisfied
4348 and false otherwise.
4350 NOTE: This is an extension of Concepts Lite TS that
4351 allows constraints to be used in expressions. */
4353 {
4359 }
4362 }
4365 }
4367 /* Free all the conversions we allocated. */
4371 }
4373 /* Build a call to a global operator new. FNNAME is the name of the
4374 operator (either "operator new" or "operator new[]") and ARGS are
4375 the arguments provided. This may change ARGS. *SIZE points to the
4376 total number of bytes required by the allocation, and is updated if
4377 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4378 be used. If this function determines that no cookie should be
4379 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4380 is not NULL_TREE, it is evaluated before calculating the final
4381 array size, and if it fails, the array size is replaced with
4382 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4383 is non-NULL, it will be set, upon return, to the allocation
4384 function called. */
4386 tree
4391 {
4393 tree fns;
4400 /* Set to (size_t)-1 if the size check fails. */
4402 {
4408 }
4414 /* Based on:
4416 [expr.new]
4418 If this lookup fails to find the name, or if the allocated type
4419 is not a class type, the allocation function's name is looked
4420 up in the global scope.
4422 we disregard block-scope declarations of "operator new". */
4427 {
4434 /* If no aligned allocation function matches, try again without the
4435 alignment. */
4436 }
4438 /* Figure out what function is being called. */
4441 complain);
4443 /* If no suitable function could be found, issue an error message
4444 and give up. */
4446 {
4450 }
4452 /* If a cookie is required, add some extra space. Whether
4453 or not a cookie is required cannot be determined until
4454 after we know which function was called. */
4456 {
4458 tree arg_types;
4461 /* Skip the size_t parameter. */
4463 /* Check the remaining parameters (if any). */
4467 ptr_type_node))
4469 /* If we need a cookie, adjust the number of bytes allocated. */
4471 {
4472 /* Update the total size. */
4475 {
4476 /* Set to (size_t)-1 if the size check fails. */
4480 }
4481 /* Update the argument list to reflect the adjusted size. */
4483 }
4484 else
4486 }
4488 /* Tell our caller which function we decided to call. */
4492 /* Build the CALL_EXPR. */
4494 }
4496 /* Build a new call to operator(). This may change ARGS. */
4498 static tree
4500 {
4517 {
4519 /* It's no good looking for an overloaded operator() on a
4520 pointer-to-member-function. */
4524 }
4527 {
4531 }
4532 else
4536 {
4540 }
4542 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4546 {
4554 }
4559 {
4567 {
4574 add_template_conv_candidate
4578 else
4582 }
4583 }
4585 /* Be strict here because if we choose a bad conversion candidate, the
4586 errors we get won't mention the call context. */
4589 {
4591 {
4595 }
4597 }
4598 else
4599 {
4602 {
4604 {
4608 }
4610 }
4615 else
4616 {
4620 else
4621 {
4624 }
4627 }
4628 }
4630 /* Free all the conversions we allocated. */
4634 }
4636 /* Wrapper for above. */
4638 tree
4640 {
4641 tree ret;
4646 }
4648 /* Called by op_error to prepare format strings suitable for the error
4649 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4650 and a suffix (controlled by NTYPES). */
4654 {
4664 else
4668 }
4670 static void
4673 {
4678 {
4684 else
4696 else
4706 else
4717 else
4727 else
4732 else
4736 else
4741 }
4742 }
4744 /* Return the implicit conversion sequence that could be used to
4745 convert E1 to E2 in [expr.cond]. */
4749 {
4755 /* [expr.cond]
4757 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4758 implicitly converted (clause _conv_) to the type "lvalue reference to
4759 T2", subject to the constraint that in the conversion the
4760 reference must bind directly (_dcl.init.ref_) to an lvalue.
4762 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4763 implicitly converted to the type "rvalue reference to T2", subject to
4764 the constraint that the reference must bind directly. */
4766 {
4769 t1,
4770 e1,
4772 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4774 complain);
4777 }
4779 /* If E2 is a prvalue or if neither of the conversions above can be done
4780 and at least one of the operands has (possibly cv-qualified) class
4781 type: */
4785 /* [expr.cond]
4787 If E1 and E2 have class type, and the underlying class types are
4788 the same or one is a base class of the other: E1 can be converted
4789 to match E2 if the class of T2 is the same type as, or a base
4790 class of, the class of T1, and the cv-qualification of T2 is the
4791 same cv-qualification as, or a greater cv-qualification than, the
4792 cv-qualification of T1. If the conversion is applied, E1 is
4793 changed to an rvalue of type T2 that still refers to the original
4794 source class object (or the appropriate subobject thereof). */
4797 {
4799 {
4804 else
4807 }
4808 else
4810 }
4811 else
4812 /* [expr.cond]
4814 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4815 converted to the type that expression E2 would have if E2 were
4816 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4819 }
4821 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4822 arguments to the conditional expression. */
4824 static tree
4826 tsubst_flags_t complain)
4827 {
4828 tree arg2_type;
4829 tree arg3_type;
4838 /* As a G++ extension, the second argument to the conditional can be
4839 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4840 c'.) If the second operand is omitted, make sure it is
4841 calculated only once. */
4843 {
4851 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4854 else
4856 }
4858 /* If something has already gone wrong, just pass that fact up the
4859 tree. */
4869 {
4872 /* If arg1 is another cond_expr choosing between -1 and 0,
4873 then we can use its comparison. It may help to avoid
4874 additional comparison, produce more accurate diagnostics
4875 and enables folding. */
4885 /* force_rvalue can return error_mark on valid arguments. */
4896 {
4897 /* Rely on the error messages of the scalar version. */
4906 {
4914 }
4918 /* We could pass complain & tf_warning to unsafe_conversion_p,
4919 but the warnings (like Wsign-conversion) have already been
4920 given by the scalar build_conditional_expr_1. We still check
4921 unsafe_conversion_p to forbid truncating long long -> float. */
4923 {
4928 }
4930 {
4935 }
4945 }
4948 {
4954 {
4958 {
4964 }
4966 {
4972 }
4975 }
4976 }
4982 {
4985 "incompatible vector types in conditional expression: "
4989 }
4992 {
4995 }
4997 }
4999 /* [expr.cond]
5001 The first expression is implicitly converted to bool (clause
5002 _conv_). */
5004 LOOKUP_NORMAL);
5008 /* [expr.cond]
5010 If either the second or the third operand has type (possibly
5011 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
5012 array-to-pointer (_conv.array_), and function-to-pointer
5013 (_conv.func_) standard conversions are performed on the second
5014 and third operands. */
5018 {
5019 /* [expr.cond]
5021 One of the following shall hold:
5023 --The second or the third operand (but not both) is a
5024 throw-expression (_except.throw_); the result is of the type
5025 and value category of the other.
5027 --Both the second and the third operands have type void; the
5028 result is of type void and is a prvalue. */
5031 {
5034 }
5037 {
5040 }
5042 {
5045 }
5046 else
5047 {
5049 {
5052 "second operand to the conditional operator "
5053 "is of type %<void%>, but the third operand is "
5055 else
5057 "third operand to the conditional operator "
5058 "is of type %<void%>, but the second operand is "
5060 }
5062 }
5065 }
5066 /* [expr.cond]
5068 Otherwise, if the second and third operand have different types,
5069 and either has (possibly cv-qualified) class type, or if both are
5070 glvalues of the same value category and the same type except for
5071 cv-qualification, an attempt is made to convert each of those operands
5072 to the type of the other. */
5076 arg3_type)
5079 {
5084 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5090 /* [expr.cond]
5092 If both can be converted, or one can be converted but the
5093 conversion is ambiguous, the program is ill-formed. If
5094 neither can be converted, the operands are left unchanged and
5095 further checking is performed as described below. If exactly
5096 one conversion is possible, that conversion is applied to the
5097 chosen operand and the converted operand is used in place of
5098 the original operand for the remainder of this section. */
5103 {
5105 {
5112 else
5114 }
5116 }
5118 {
5122 /* Even if CONV2 is a valid conversion, the result of the
5123 conversion may be invalid. For example, if ARG3 has type
5124 "volatile X", and X does not have a copy constructor
5125 accepting a "volatile X&", then even if ARG2 can be
5126 converted to X, the conversion will fail. */
5130 }
5132 {
5139 }
5141 /* Free all the conversions we allocated. */
5147 /* If, after the conversion, both operands have class type,
5148 treat the cv-qualification of both operands as if it were the
5149 union of the cv-qualification of the operands.
5151 The standard is not clear about what to do in this
5152 circumstance. For example, if the first operand has type
5153 "const X" and the second operand has a user-defined
5154 conversion to "volatile X", what is the type of the second
5155 operand after this step? Making it be "const X" (matching
5156 the first operand) seems wrong, as that discards the
5157 qualification without actually performing a copy. Leaving it
5158 as "volatile X" seems wrong as that will result in the
5159 conditional expression failing altogether, even though,
5160 according to this step, the one operand could be converted to
5161 the type of the other. */
5169 }
5171 /* [expr.cond]
5173 If the second and third operands are glvalues of the same value
5174 category and have the same type, the result is of that type and
5175 value category. */
5179 {
5184 }
5186 /* [expr.cond]
5188 Otherwise, the result is an rvalue. If the second and third
5189 operand do not have the same type, and either has (possibly
5190 cv-qualified) class type, overload resolution is used to
5191 determine the conversions (if any) to be applied to the operands
5192 (_over.match.oper_, _over.built_). */
5196 {
5201 /* Rearrange the arguments so that add_builtin_candidate only has
5202 to know about two args. In build_builtin_candidate, the
5203 arguments are unscrambled. */
5208 COND_EXPR,
5209 NOP_EXPR,
5211 args,
5214 /* [expr.cond]
5216 If the overload resolution fails, the program is
5217 ill-formed. */
5220 {
5225 }
5228 {
5230 {
5233 }
5235 }
5237 /* [expr.cond]
5239 Otherwise, the conversions thus determined are applied, and
5240 the converted operands are used in place of the original
5241 operands for the remainder of this section. */
5250 }
5252 /* [expr.cond]
5254 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5255 and function-to-pointer (_conv.func_) standard conversions are
5256 performed on the second and third operands.
5258 We need to force the lvalue-to-rvalue conversion here for class types,
5259 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5260 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5261 regions. */
5274 /* [expr.cond]
5276 After those conversions, one of the following shall hold:
5278 --The second and third operands have the same type; the result is of
5279 that type. */
5282 /* [expr.cond]
5284 --The second and third operands have arithmetic or enumeration
5285 type; the usual arithmetic conversions are performed to bring
5286 them to a common type, and the result is of that type. */
5291 {
5292 /* In this case, there is always a common type. */
5294 arg3_type);
5297 "implicit conversion from %qH to %qI to "
5299 loc);
5303 {
5307 /* Two enumerators from the same enumeration can have different
5313 }
5320 {
5324 }
5328 }
5329 /* [expr.cond]
5331 --The second and third operands have pointer type, or one has
5332 pointer type and the other is a null pointer constant; pointer
5333 conversions (_conv.ptr_) and qualification conversions
5334 (_conv.qual_) are performed to bring them to their composite
5335 pointer type (_expr.rel_). The result is of the composite
5336 pointer type.
5338 --The second and third operands have pointer to member type, or
5339 one has pointer to member type and the other is a null pointer
5340 constant; pointer to member conversions (_conv.mem_) and
5341 qualification conversions (_conv.qual_) are performed to bring
5342 them to a common type, whose cv-qualification shall match the
5343 cv-qualification of either the second or the third operand.
5344 The result is of the common type. */
5352 {
5355 complain);
5360 }
5363 {
5368 }
5373 valid_operands:
5375 {
5376 /* Let lvalue_kind know this was a glvalue. */
5379 }
5383 /* If the ARG2 and ARG3 are the same and don't have side-effects,
5384 warn here, because the COND_EXPR will be turned into ARG2. */
5391 /* We can't use result_type below, as fold might have returned a
5392 throw_expr. */
5395 {
5396 /* Expand both sides into the same slot, hopefully the target of
5397 the ?: expression. We used to check for TARGET_EXPRs here,
5398 but now we sometimes wrap them in NOP_EXPRs so the test would
5399 fail. */
5402 /* If this expression is an rvalue, but might be mistaken for an
5403 lvalue, we must add a NON_LVALUE_EXPR. */
5405 }
5406 else
5410 }
5412 /* Wrapper for above. */
5414 tree
5416 tsubst_flags_t complain)
5417 {
5418 tree ret;
5423 }
5425 /* OPERAND is an operand to an expression. Perform necessary steps
5426 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5427 returned. */
5429 static tree
5431 {
5433 {
5436 /* Make sure the template type is instantiated now. */
5438 }
5441 }
5443 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5444 OVERLOAD) to the CANDIDATES, returning an updated list of
5445 CANDIDATES. The ARGS are the arguments provided to the call;
5446 if FIRST_ARG is non-null it is the implicit object argument,
5447 otherwise the first element of ARGS is used if needed. The
5448 EXPLICIT_TARGS are explicit template arguments provided.
5449 TEMPLATE_ONLY is true if only template functions should be
5450 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5451 add_function_candidate. */
5453 static void
5455 tree return_type,
5460 tsubst_flags_t complain)
5461 {
5462 tree ctype;
5466 unification_kind_t strict;
5471 /* Precalculate special handling of constructors and conversion ops. */
5474 {
5478 /* We're doing return_type(x). */
5480 else
5481 /* We're doing x.operator return_type(). */
5483 /* [over.match.funcs] For conversion functions, the function
5484 is considered to be a member of the class of the implicit
5485 object argument for the purpose of defining the type of
5486 the implicit object parameter. */
5488 }
5489 else
5490 {
5492 {
5494 /* For list-initialization we consider explicit constructors
5495 and complain if one is chosen. */
5496 check_converting
5499 }
5502 }
5506 else
5507 /* Delay creating the implicit this parameter until it is needed. */
5511 {
5523 {
5524 /* Figure out where the object arg comes from. If this
5525 function is a non-static member and we didn't get an
5526 implicit object argument, move it out of args. */
5528 {
5530 tree arg;
5537 }
5541 }
5545 fn,
5546 ctype,
5547 explicit_targs,
5548 fn_first_arg,
5549 fn_args,
5550 return_type,
5551 access_path,
5552 conversion_path,
5553 flags,
5554 strict,
5555 complain);
5558 fn,
5559 ctype,
5560 fn_first_arg,
5561 fn_args,
5562 access_path,
5563 conversion_path,
5564 flags,
5565 NULL,
5566 complain);
5567 }
5568 }
5570 /* Returns 1 if P0145R2 says that the LHS of operator CODE is evaluated first,
5571 -1 if the RHS is evaluated first, or 0 if the order is unspecified. */
5573 static int
5575 {
5577 {
5578 // 5. b @= a
5582 // 6. a[b]
5586 // 1. a.b
5587 // Not overloadable (yet).
5588 // 2. a->b
5589 // Only one argument.
5590 // 3. a->*b
5592 // 7. a << b
5594 // 8. a >> b
5600 }
5601 }
5603 static tree
5606 {
5627 {
5630 }
5637 {
5642 /* Use build_op_new_call and build_op_delete_call instead. */
5646 /* Use build_op_call instead. */
5653 /* These are saved for the sake of warn_logical_operator. */
5663 /* These are saved for the sake of maybe_warn_bool_compare. */
5668 /* =, ->, [], () must be non-static member functions. */
5672 /* FALLTHRU */
5680 }
5686 /* Use build_conditional_expr instead. */
5702 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5705 /* Add namespace-scope operators to the list of functions to
5706 consider. */
5708 {
5714 }
5720 /* Add class-member operators to the candidate set. */
5722 {
5723 tree fns;
5727 {
5730 }
5738 }
5739 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5740 only non-member functions that have type T1 or reference to
5741 cv-qualified-opt T1 for the first argument, if the first argument
5742 has an enumeration type, or T2 or reference to cv-qualified-opt
5743 T2 for the second argument, if the second argument has an
5744 enumeration type. Filter out those that don't match. */
5746 {
5750 {
5760 {
5766 && (same_type_ignoring_top_level_qualifiers_p
5771 }
5773 /* No argument has an appropriate type, so remove this
5774 candidate function from the list. */
5776 {
5779 }
5780 }
5781 }
5787 {
5790 /* For these, the built-in candidates set is empty
5791 [over.match.oper]/3. We don't want non-strict matches
5792 because exact matches are always possible with built-in
5793 operators. The built-in candidate set for COMPONENT_REF
5794 would be empty too, but since there are no such built-in
5795 operators, we accept non-strict matches for them. */
5802 }
5806 {
5808 {
5811 /* Don't try anything fancy if we're not allowed to produce
5812 errors. */
5816 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5817 distinguish between prefix and postfix ++ and
5818 operator++() was used for both, so we allow this with
5819 -fpermissive. */
5820 else
5821 {
5827 }
5834 else
5840 /* The caller will deal with these. */
5850 {
5851 /* If one of the arguments of the operator represents
5852 an invalid use of member function pointer, try to report
5853 a meaningful error ... */
5858 else
5859 {
5860 /* ... Otherwise, report the more generic
5861 "no matching operator found" error */
5864 }
5865 }
5868 }
5869 }
5870 else
5871 {
5874 {
5876 {
5879 }
5881 }
5883 {
5889 else
5895 {
5900 /* This prevents build_new_function_call from discarding this
5901 function during instantiation of the enclosing template. */
5904 /* Specify evaluation order as per P0145R2. */
5907 {
5918 }
5919 }
5920 }
5921 else
5922 {
5923 /* Give any warnings we noticed during overload resolution. */
5925 {
5929 }
5931 /* Check for comparison of different enum types. */
5933 {
5945 {
5949 }
5953 }
5955 /* We need to strip any leading REF_BIND so that bitfields
5956 don't cause errors. This should not remove any important
5957 conversions, because builtins don't apply to class
5958 objects directly. */
5965 {
5969 else
5972 /* We need to call warn_logical_operator before
5973 converting arg2 to a boolean_type, but after
5974 decaying an enumerator to its value. */
5981 }
5983 {
5988 }
5990 }
5991 }
5993 user_defined_result_ready:
5995 /* Free all the conversions we allocated. */
6001 builtin:
6003 {
6018 /* Fall through. */
6031 /* Fall through. */
6064 complain),
6067 /* The caller will deal with these. */
6075 }
6077 }
6079 /* Wrapper for above. */
6081 tree
6085 {
6086 tree ret;
6092 }
6094 /* CALL was returned by some call-building function; extract the actual
6095 CALL_EXPR from any bits that have been tacked on, e.g. by
6096 convert_from_reference. */
6098 tree
6100 {
6111 }
6113 /* Returns true if FN has two parameters, of which the second has type
6114 size_t. */
6116 static bool
6118 {
6130 }
6132 /* True if T, an allocation function, has std::align_val_t as its second
6133 argument. */
6135 bool
6137 {
6143 }
6145 /* Returns true iff T, an element of an OVERLOAD chain, is a usual deallocation
6146 function (3.7.4.2 [basic.stc.dynamic.deallocation]) with a parameter of
6147 std::align_val_t. */
6149 static bool
6151 {
6155 /* A template instance is never a usual deallocation function,
6156 regardless of its signature. */
6172 }
6174 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
6175 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
6177 bool
6179 {
6180 /* A template instance is never a usual deallocation function,
6181 regardless of its signature. */
6186 /* If a class T has a member deallocation function named operator delete
6187 with exactly one parameter, then that function is a usual
6188 (non-placement) deallocation function. If class T does not declare
6189 such an operator delete but does declare a member deallocation
6190 function named operator delete with exactly two parameters, the second
6191 of which has type std::size_t (18.2), then this function is a usual
6192 deallocation function. */
6204 }
6206 /* Build a call to operator delete. This has to be handled very specially,
6207 because the restrictions on what signatures match are different from all
6208 other call instances. For a normal delete, only a delete taking (void *)
6209 or (void *, size_t) is accepted. For a placement delete, only an exact
6210 match with the placement new is accepted.
6212 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
6213 ADDR is the pointer to be deleted.
6214 SIZE is the size of the memory block to be deleted.
6215 GLOBAL_P is true if the delete-expression should not consider
6216 class-specific delete operators.
6217 PLACEMENT is the corresponding placement new call, or NULL_TREE.
6219 If this call to "operator delete" is being generated as part to
6220 deallocate memory allocated via a new-expression (as per [expr.new]
6221 which requires that if the initialization throws an exception then
6222 we call a deallocation function), then ALLOC_FN is the allocation
6223 function. */
6225 tree
6229 {
6243 /* In [class.free]
6245 If the result of the lookup is ambiguous or inaccessible, or if
6246 the lookup selects a placement deallocation function, the
6247 program is ill-formed.
6249 Therefore, we ask lookup_fnfields to complain about ambiguity. */
6250 {
6254 }
6255 else
6261 /* Strip const and volatile from addr. */
6265 {
6266 /* "A declaration of a placement deallocation function matches the
6267 declaration of a placement allocation function if it has the same
6268 number of parameters and, after parameter transformations (8.3.5),
6269 all parameter types except the first are identical."
6271 So we build up the function type we want and ask instantiate_type
6272 to get it for us. */
6283 /* "If the lookup finds the two-parameter form of a usual deallocation
6284 function (3.7.4.2) and that function, considered as a placement
6285 deallocation function, would have been selected as a match for the
6286 allocation function, the program is ill-formed." */
6288 {
6296 /* But if the class has an operator delete (void *), then that is
6297 the usual deallocation function, so we shouldn't complain
6298 about using the operator delete (void *, size_t). */
6302 {
6307 }
6308 /* Before C++14 a two-parameter global deallocation function is
6309 always a placement deallocation function, but warn if
6310 -Wc++14-compat. */
6312 {
6317 }
6320 {
6322 {
6323 /* Only mention C++14 for namespace-scope delete. */
6326 else
6328 "%qD is a usual (non-placement) deallocation "
6330 }
6331 }
6332 else
6334 ok:;
6335 }
6336 }
6337 else
6338 /* "Any non-placement deallocation function matches a non-placement
6339 allocation function. If the lookup finds a single matching
6340 deallocation function, that function will be called; otherwise, no
6341 deallocation function will be called." */
6343 {
6346 {
6348 {
6351 }
6353 /* -- If the type has new-extended alignment, a function with a
6354 parameter of type std::align_val_t is preferred; otherwise a
6355 function without such a parameter is preferred. If exactly one
6356 preferred function is found, that function is selected and the
6357 selection process terminates. If more than one preferred
6358 function is found, all non-preferred functions are eliminated
6359 from further consideration. */
6361 {
6367 {
6371 }
6372 }
6374 /* -- If the deallocation functions have class scope, the one
6375 without a parameter of type std::size_t is selected. */
6380 /* -- If the type is complete and if, for the second alternative
6381 (delete array) only, the operand is a pointer to a class type
6382 with a non-trivial destructor or a (possibly multi-dimensional)
6383 array thereof, the function with a parameter of type std::size_t
6384 is selected.
6386 -- Otherwise, it is unspecified whether a deallocation function
6387 with a parameter of type std::size_t is selected. */
6388 else
6389 {
6393 /* We need a cookie to determine the array size. */
6395 }
6401 }
6402 }
6404 /* If we have a matching function, call it. */
6406 {
6409 /* If the FN is a member function, make sure that it is
6410 accessible. */
6413 complain);
6415 /* Core issue 901: It's ok to new a type with deleted delete. */
6420 {
6421 /* The placement args might not be suitable for overload
6422 resolution at this point, so build the call directly. */
6432 }
6433 else
6434 {
6435 tree ret;
6441 {
6444 }
6448 }
6449 }
6451 /* [expr.new]
6453 If no unambiguous matching deallocation function can be found,
6454 propagating the exception does not cause the object's memory to
6455 be freed. */
6457 {
6461 alloc_fn);
6463 }
6469 }
6471 /* If the current scope isn't allowed to access DECL along
6472 BASETYPE_PATH, give an error. The most derived class in
6473 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6474 the declaration to use in the error diagnostic. */
6476 bool
6479 {
6484 {
6485 /* 7.3.3/18: The additional constructors are accessible if they would be
6486 accessible when used to construct an object of the corresponding base
6487 class. */
6491 }
6494 {
6496 {
6500 {
6506 }
6508 {
6514 }
6515 else
6516 {
6521 }
6522 }
6524 }
6527 }
6529 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6530 bitwise or of LOOKUP_* values. If any errors are warnings are
6531 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6532 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6533 to NULL. */
6535 static tree
6538 {
6544 /* If the source is a packed field, calling the copy constructor will require
6545 binding the field to the reference parameter to the copy constructor, and
6546 we'll end up with an infinite loop. If we can use a bitwise copy, then
6547 do that now. */
6563 }
6565 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6566 Also handle a subset of zero as null warnings.
6567 EXPR is implicitly converted to type TOTYPE.
6568 FN and ARGNUM are used for diagnostics. */
6570 static void
6572 {
6573 /* Issue warnings about peculiar, but valid, uses of NULL. */
6576 {
6577 source_location loc =
6584 else
6587 }
6589 /* Issue warnings if "false" is converted to a NULL pointer */
6592 {
6595 "converting %<false%> to pointer type for argument %P "
6597 else
6600 }
6601 /* Handle zero as null pointer warnings for cases other
6602 than EQ_EXPR and NE_EXPR */
6605 {
6606 source_location loc =
6609 }
6610 }
6612 /* We gave a diagnostic during a conversion. If this was in the second
6613 standard conversion sequence of a user-defined conversion sequence, say
6614 which user-defined conversion. */
6616 static void
6618 {
6622 {
6626 }
6627 }
6629 /* Locate the parameter with the given index within FNDECL.
6630 ARGNUM is zero based, -1 indicates the `this' argument of a method.
6631 Return the location of the FNDECL itself if there are problems. */
6633 location_t
6635 {
6637 tree param;
6639 /* Locate param by index within DECL_ARGUMENTS (fndecl). */
6643 ;
6645 /* If something went wrong (e.g. if we have a builtin and thus no arguments),
6646 return the location of FNDECL. */
6651 }
6653 /* Perform the conversions in CONVS on the expression EXPR. FN and
6654 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6655 indicates the `this' argument of a method. INNER is nonzero when
6656 being called to continue a conversion chain. It is negative when a
6657 reference binding will be applied, positive otherwise. If
6658 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6659 conversions will be emitted if appropriate. If C_CAST_P is true,
6660 this conversion is coming from a C-style cast; in that case,
6661 conversions to inaccessible bases are permitted. */
6663 static tree
6667 {
6669 diagnostic_t diag_kind;
6685 {
6689 /* Give a helpful error if this is bad because of excess braces. */
6694 {
6700 }
6702 /* Give a helpful error if this is bad because a conversion to bool
6703 from std::nullptr_t requires direct-initialization. */
6711 {
6713 {
6716 totype);
6722 complain);
6726 complain);
6727 else
6733 }
6735 {
6739 complain);
6741 }
6746 complain);
6749 }
6758 }
6764 {
6766 {
6770 /* We chose the surrogate function from add_conv_candidate, now we
6771 actually need to build the conversion. */
6777 /* When converting from an init list we consider explicit
6778 constructors, but actually trying to call one is an error. */
6781 /* Unless this is for direct-list-initialization. */
6783 /* And in C++98 a default constructor can't be explicit. */
6785 {
6791 {
6797 }
6798 else
6801 }
6803 /* If we're initializing from {}, it's value-initialization. */
6807 {
6814 {
6817 }
6819 }
6823 /* Pass LOOKUP_NO_CONVERSION so rvalue/base handling knows not to allow
6824 any more UDCs. */
6826 complain);
6828 /* If this is a constructor or a function returning an aggr type,
6829 we need to build up a TARGET_EXPR. */
6831 {
6834 /* Remember that this was list-initialization. */
6837 }
6840 }
6843 {
6849 else
6851 }
6860 /* If __null has been converted to an integer type, we do not want to
6861 continue to warn about uses of EXPR as an integer, rather than as a
6862 pointer. */
6866 /* We leave bad_p off ck_ambig because overload resolution considers
6867 it valid, it just fails when we try to perform it. So we need to
6868 check complain here, too. */
6870 {
6871 /* Call build_user_type_conversion again for the error. */
6879 }
6883 {
6884 /* Conversion to std::initializer_list<T>. */
6892 /* Convert all the elements. */
6894 {
6905 }
6906 /* Build up the array. */
6907 elttype = cp_build_qualified_type
6911 /* Take the address explicitly rather than via decay_conversion
6912 to avoid the error about taking the address of a temporary. */
6918 /* Build up the initializer_list object. Note: fail gracefully
6919 if the object cannot be completed because, for example, no
6920 definition is provided (c++/80956). */
6930 }
6934 {
6943 }
6946 complain);
6953 };
6963 {
6967 {
6969 {
6974 }
6976 }
6981 /* Don't introduce copies when passing arguments along to the inherited
6982 constructor. */
6984 && flag_new_inheriting_ctors
6990 /* Copy-list-initialization doesn't actually involve a copy. */
6993 /* Fall through. */
6996 {
6997 /* We are going to bind a reference directly to a base-class
6998 subobject of EXPR. */
6999 /* Build an expression for `*((base*) &expr)'. */
7003 }
7005 /* Copy-initialization where the cv-unqualified version of the source
7006 type is the same class as, or a derived class of, the class of the
7007 destination [is treated as direct-initialization]. [dcl.init] */
7010 /* This conversion is being done in the context of a user-defined
7011 conversion (i.e. the second step of copy-initialization), so
7012 don't allow any more. */
7014 else
7017 /* standard_conversion got LOOKUP_PREFER_RVALUE. */
7021 {
7026 }
7031 {
7035 {
7048 else
7055 }
7057 /* If necessary, create a temporary.
7059 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
7060 that need temporaries, even when their types are reference
7061 compatible with the type of reference being bound, so the
7062 upcoming call to cp_build_addr_expr doesn't fail. */
7066 {
7067 /* Otherwise, a temporary of type "cv1 T1" is created and
7068 initialized from the initializer expression using the rules
7069 for a non-reference copy-initialization (8.5). */
7078 {
7079 /* If the reference is volatile or non-const, we
7080 cannot create a temporary. */
7087 else
7091 }
7092 /* If the source is a packed field, and we must use a copy
7093 constructor, then building the target expr will require
7094 binding the field to the reference parameter to the
7095 copy constructor, and we'll end up with an infinite
7096 loop. If we can use a bitwise copy, then we'll be
7097 OK. */
7101 {
7105 }
7107 {
7110 }
7112 }
7114 /* Take the address of the thing to which we will bind the
7115 reference. */
7120 /* Convert it to a pointer to the type referred to by the
7121 reference. This will adjust the pointer if a derived to
7122 base conversion is being performed. */
7125 /* Convert the pointer to the desired reference type. */
7127 }
7133 /* ??? Should the address of a transaction-safe pointer point to the TM
7134 clone, and this conversion look up the primary function? */
7138 /* Warn about deprecated conversion if appropriate. */
7154 }
7164 else
7168 }
7170 /* ARG is being passed to a varargs function. Perform any conversions
7171 required. Return the converted value. */
7173 tree
7175 {
7176 tree arg_type;
7179 /* [expr.call]
7181 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
7182 standard conversions are performed. */
7185 /* [expr.call]
7187 If the argument has integral or enumeration type that is subject
7188 to the integral promotions (_conv.prom_), or a floating point
7189 type that is subject to the floating point promotion
7190 (_conv.fpprom_), the value of the argument is converted to the
7191 promoted type before the call. */
7196 {
7200 "implicit conversion from %qH to %qI when passing "
7204 }
7208 {
7210 {
7212 complain);
7222 }
7223 else
7225 }
7231 /* In a template (or ill-formed code), we can have an incomplete type
7232 even after require_complete_type_sfinae, in which case we don't know
7233 whether it has trivial copy or not. */
7236 {
7237 /* [expr.call] 5.2.2/7:
7238 Passing a potentially-evaluated argument of class type (Clause 9)
7239 with a non-trivial copy constructor or a non-trivial destructor
7240 with no corresponding parameter is conditionally-supported, with
7241 implementation-defined semantics.
7243 We support it as pass-by-invisible-reference, just like a normal
7244 value parameter.
7246 If the call appears in the context of a sizeof expression,
7247 it is not potentially-evaluated. */
7250 {
7254 "passing objects of non-trivially-copyable "
7256 arg_type);
7258 }
7259 /* Build up a real lvalue-to-rvalue conversion in case the
7260 copy constructor is trivial but not callable. */
7264 }
7267 }
7269 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
7271 tree
7273 {
7275 {
7279 }
7289 {
7292 }
7296 {
7297 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
7298 it as pass by invisible reference. */
7300 "receiving objects of non-trivially-copyable type %q#T "
7306 }
7310 /* Wrap the VA_ARG_EXPR in a TARGET_EXPR now so other code doesn't need to
7311 know how to handle it. */
7314 }
7316 /* TYPE has been given to va_arg. Apply the default conversions which
7317 would have happened when passed via ellipsis. Return the promoted
7318 type, or the passed type if there is no change. */
7320 tree
7322 {
7323 tree promote;
7325 /* Perform the array-to-pointer and function-to-pointer
7326 conversions. */
7334 }
7336 /* ARG is a default argument expression being passed to a parameter of
7337 the indicated TYPE, which is a parameter to FN. PARMNUM is the
7338 zero-based argument number. Do any required conversions. Return
7339 the converted value. */
7342 void
7346 void
7350 tree
7352 tsubst_flags_t complain)
7353 {
7355 tree t;
7357 /* See through clones. */
7359 /* And inheriting ctors. */
7363 /* Detect recursion. */
7366 {
7370 }
7372 /* If the ARG is an unparsed default argument expression, the
7373 conversion cannot be performed. */
7375 {
7380 }
7387 /* Due to:
7389 [dcl.fct.default]
7391 The names in the expression are bound, and the semantic
7392 constraints are checked, at the point where the default
7393 expressions appears.
7395 we must not perform access checks here. */
7397 /* We must make a copy of ARG, in case subsequent processing
7398 alters any part of it. */
7403 complain);
7410 }
7412 /* Returns the type which will really be used for passing an argument of
7413 type TYPE. */
7415 tree
7417 {
7418 /* Pass classes with copy ctors by invisible reference. */
7420 {
7422 /* There are no other pointers to this temporary. */
7424 }
7432 }
7434 /* Actually perform the appropriate conversion. */
7436 tree
7438 {
7439 tree bitfield_type;
7441 /* If VAL is a bitfield, then -- since it has already been converted
7442 to TYPE -- it cannot have a precision greater than TYPE.
7444 If it has a smaller precision, we must widen it here. For
7445 example, passing "int f:3;" to a function expecting an "int" will
7446 not result in any conversion before this point.
7448 If the precision is the same we must not risk widening. For
7449 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
7450 often have type "int", even though the C++ type for the field is
7451 "long long". If the value is being passed to a function
7452 expecting an "int", then no conversions will be required. But,
7453 if we call convert_bitfield_to_declared_type, the bitfield will
7454 be converted to "long long". */
7461 ;
7462 /* Pass classes with copy ctors by invisible reference. */
7471 {
7473 {
7481 "argument of function call might be a candidate "
7483 }
7485 }
7487 }
7489 /* Returns non-zero iff FN is a function with magic varargs, i.e. ones for
7490 which just decay_conversion or no conversions at all should be done.
7491 This is true for some builtins which don't act like normal functions.
7492 Return 2 if no conversions at all should be done, 1 if just
7493 decay_conversion. Return 3 for special treatment of the 3rd argument
7494 for __builtin_*_overflow_p. */
7496 int
7498 {
7501 {
7516 }
7519 }
7521 /* Returns the decl of the dispatcher function if FN is a function version. */
7523 tree
7525 {
7535 {
7539 }
7544 }
7546 /* fn is a function version dispatcher that is marked used. Mark all the
7547 semantically identical function versions it will dispatch as used. */
7549 void
7551 {
7568 /* All semantically identical versions are chained. Traverse and mark each
7569 one of them as used. */
7572 {
7575 }
7576 }
7578 /* Build a call to "the copy constructor" for the type of A, even if it
7579 wouldn't be selected by normal overload resolution. Used for
7580 diagnostics. */
7582 static tree
7584 {
7595 }
7597 /* Return true iff T refers to a base field. */
7599 static bool
7601 {
7610 }
7612 /* We can't elide a copy from a function returning by value to a base
7613 subobject, as the callee might clobber tail padding. Return true iff this
7614 could be that case. */
7616 static bool
7618 {
7619 /* Copy elision only happens with a TARGET_EXPR. */
7623 /* It's safe to elide the copy for a class with no tail padding. */
7626 /* It's safe to elide the copy if we aren't initializing a base object. */
7630 /* build_compound_expr pushes COMPOUND_EXPR inside TARGET_EXPR. */
7634 {
7635 /* We'll end up copying from each of the arms of the COND_EXPR directly
7636 into the target, so look at them. */
7641 }
7644 }
7646 /* True iff C is a conversion that binds a reference to a prvalue. */
7648 static bool
7650 {
7667 }
7669 /* Call the trivial destructor for INSTANCE, which can be either an lvalue of
7670 class type or a pointer to class type. */
7672 tree
7674 {
7678 {
7679 no_clobber:
7681 }
7684 {
7688 }
7690 /* A trivial destructor should still clobber the object. */
7694 }
7696 /* Subroutine of the various build_*_call functions. Overload resolution
7697 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7698 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7699 bitmask of various LOOKUP_* flags which apply to the call itself. */
7701 static tree
7703 {
7711 tree val;
7720 /* In a template, there is no need to perform all of the work that
7721 is normally done. We are only interested in the type of the call
7722 expression, i.e., the return type of the function. Any semantic
7723 errors will be deferred until the template is instantiated. */
7725 {
7727 tree return_type;
7733 else
7734 /* Otherwise set TREE_USED for the benefit of -Wunused-function.
7735 See PR80598. */
7742 else
7743 {
7746 tree arg;
7754 }
7764 }
7766 /* Give any warnings we noticed during overload resolution. */
7768 {
7772 }
7774 /* Core issue 2327: P0135 doesn't say how to handle the case where the
7775 argument to the copy constructor ends up being a prvalue after
7776 conversion. Let's do the normal processing, but pretend we aren't
7777 actually using the copy constructor. */
7785 {
7788 }
7790 /* OK, we're actually calling this inherited constructor; set its deletedness
7791 appropriately. We can get away with doing this here because calling is
7792 the only way to refer to a constructor. */
7796 /* Make =delete work with SFINAE. */
7798 {
7802 }
7805 {
7806 tree access_fn;
7807 /* If FN is a template function, two cases must be considered.
7808 For example:
7810 struct A {
7811 protected:
7812 template <class T> void f();
7813 };
7814 template <class T> struct B {
7815 protected:
7816 void g();
7817 };
7818 struct C : A, B<int> {
7819 using A::f; // #1
7820 using B<int>::g; // #2
7821 };
7823 In case #1 where `A::f' is a member template, DECL_ACCESS is
7824 recorded in the primary template but not in its specialization.
7825 We check access of FN using its primary template.
7827 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7828 because it is a member of class template B, DECL_ACCESS is
7829 recorded in the specialization `B<int>::g'. We cannot use its
7830 primary template because `B<T>::g' and `B<int>::g' may have
7831 different access. */
7835 else
7840 }
7842 /* If we're checking for implicit delete, don't bother with argument
7843 conversions. */
7845 {
7849 /* Reject bad conversions now. */
7851 /* else continue to get conversion error. */
7852 }
7854 not_really_used:
7856 /* N3276 magic doesn't apply to nested calls. */
7859 /* No-Cleanup doesn't apply to nested calls either. */
7863 /* Find maximum size of vector to hold converted arguments. */
7870 /* The implicit parameters to a constructor are not considered by overload
7871 resolution, and must be of the proper type. */
7873 {
7874 tree object_arg;
7876 {
7879 }
7880 else
7881 {
7884 }
7887 /* We should never try to call the abstract constructor. */
7891 {
7895 }
7898 {
7899 /* The implicit move specified in 15.8.3/3 fails "...if the type of
7900 the first parameter of the selected constructor is not an rvalue
7901 reference to the object’s type (possibly cv-qualified)...." */
7908 }
7909 }
7910 /* Bypass access control for 'this' parameter. */
7912 {
7915 ? first_arg
7918 tree converted_arg;
7919 tree base_binfo;
7925 {
7927 {
7932 }
7933 else
7935 }
7937 /* See if the function member or the whole class type is declared
7938 final and the call can be devirtualized. */
7943 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7944 X is called for an object that is not of type X, or of a type
7945 derived from X, the behavior is undefined.
7947 So we can assume that anything passed as 'this' is non-null, and
7948 optimize accordingly. */
7950 /* Convert to the base in which the function was declared. */
7953 arg,
7956 /* Check that the base class is accessible. */
7959 {
7964 else
7966 }
7967 /* If fn was found by a using declaration, the conversion path
7968 will be to the derived class, not the base declaring fn. We
7969 must convert from derived to base. */
7980 else
7984 }
7989 {
7996 /* If the argument is NULL and used to (implicitly) instantiate a
7997 template function (and bind one of the template arguments to
7998 the type of 'long int'), we don't want to warn about passing NULL
7999 to non-pointer argument.
8000 For example, if we have this template function:
8002 template<typename T> void func(T x) {}
8004 we want to warn (when -Wconversion is enabled) in this case:
8006 void foo() {
8007 func<int>(NULL);
8008 }
8010 but not in this case:
8012 void foo() {
8013 func(NULL);
8014 }
8015 */
8022 /* Warn about initializer_list deduction that isn't currently in the
8023 working draft. */
8025 && flag_deduce_init_list
8029 {
8042 {
8050 }
8051 }
8053 /* Set user_conv_p on the argument conversions, so rvalue/base handling
8054 knows not to allow any more UDCs. This needs to happen after we
8055 process cand->warnings. */
8064 arg_complain);
8069 else
8071 }
8073 /* Default arguments */
8075 {
8081 complain);
8085 }
8087 /* Ellipsis */
8090 {
8093 {
8094 /* Do no conversions for certain magic varargs. */
8098 }
8100 /* For other magic varargs only do decay_conversion. */
8105 {
8106 /* Avoid infinite recursion trying to call A(...). */
8108 /* Try to call the actual copy constructor for a good error. */
8111 }
8112 else
8117 }
8122 /* Avoid to do argument-transformation, if warnings for format, and for
8123 nonnull are disabled. Just in case that at least one of them is active
8124 the check_function_arguments function might warn about something. */
8128 || warn_format
8129 || warn_suggest_attribute_format
8131 {
8135 {
8136 /* For -Wformat undo the implicit passing by hidden reference
8137 done by convert_arg_to_ellipsis. */
8141 else
8143 }
8147 }
8150 {
8151 /* Check for passing ellipsis arguments to an inherited constructor. We
8152 could handle this by open-coding the inherited constructor rather than
8153 defining it, but let's not bother now. */
8157 {
8159 {
8163 }
8165 }
8167 /* A base constructor inheriting from a virtual base doesn't get the
8168 inherited arguments, just this and __vtt. */
8171 }
8173 /* Avoid actually calling copy constructors and copy assignment operators,
8174 if possible. */
8181 /* It's unsafe to elide the constructor when handling
8182 a noexcept-expression, it may evaluate to the wrong
8183 value (c++/53025). */
8185 {
8186 tree targ;
8188 tree fa;
8191 /* Pull out the real argument, disregarding const-correctness. */
8193 /* Strip the reference binding for the constructor parameter. */
8197 /* But don't strip any other reference bindings; binding a temporary to a
8198 reference prevents copy elision. */
8204 {
8209 }
8210 else
8215 else
8218 /* In C++17 we shouldn't be copying a TARGET_EXPR except into a base
8219 subobject. */
8222 || force_elide
8223 /* It's from binding the ref parm to a packed field. */
8226 /* See unsafe_copy_elision_p. */
8233 /* [class.copy]: the copy constructor is implicitly defined even if the
8234 implementation elided its use. But don't warn about deprecation when
8235 eliding a temporary, as then no copy is actually performed. */
8240 {
8244 }
8245 else
8248 /* If we're creating a temp and we already have one, don't create a
8249 new one. If we're not creating a temp but we get one, use
8250 INIT_EXPR to collapse the temp into our target. Otherwise, if the
8251 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
8252 temp or an INIT_EXPR otherwise. */
8254 {
8259 }
8262 {
8267 }
8268 }
8272 {
8273 tree to = cp_stabilize_reference
8281 {
8282 /* Avoid copying empty classes. */
8285 }
8287 {
8291 "assignment from temporary initializer_list does not "
8295 }
8296 else
8297 {
8298 /* We must only copy the non-tail padding parts. */
8306 build_index_type
8315 }
8320 }
8322 {
8326 {
8329 no_cleanup_complain);
8330 else
8332 }
8333 }
8341 /* Warn if the built-in writes to an object of a non-trivial type. */
8348 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
8349 virtual functions can't be constexpr. */
8351 {
8352 tree t;
8359 complain);
8365 }
8366 else
8367 {
8371 }
8377 {
8379 /* build_new_op_1 will clear this when appropriate. */
8381 }
8383 {
8387 }
8389 }
8391 namespace
8392 {
8394 /* Return the DECL of the first non-static subobject of class TYPE
8395 that satisfies the predicate PRED or null if none can be found. */
8398 tree
8400 {
8405 {
8412 }
8418 {
8424 }
8427 }
8429 struct NonPublicField
8430 {
8432 {
8434 }
8435 };
8437 /* Return the DECL of the first non-public subobject of class TYPE
8438 or null if none can be found. */
8442 {
8444 }
8446 struct NonTrivialField
8447 {
8449 {
8451 }
8452 };
8454 /* Return the DECL of the first non-trivial subobject of class TYPE
8455 or null if none can be found. */
8459 {
8461 }
8465 /* Return true if all copy and move assignment operator overloads for
8466 class TYPE are trivial and at least one of them is not deleted and,
8467 when ACCESS is set, accessible. Return false otherwise. Set
8468 HASASSIGN to true when the TYPE has a (not necessarily trivial)
8469 copy or move assignment. */
8471 static bool
8473 {
8477 /* Iterate over overloads of the assignment operator, checking
8478 accessible copy assignments for triviality. */
8481 {
8484 /* Skip operators that aren't copy assignments. */
8491 /* Skip template assignment operators and deleted functions. */
8501 /* Break early when both properties have been determined. */
8504 }
8506 /* Return true if they're all trivial and one of the expressions
8507 TYPE() = TYPE() or TYPE() = (TYPE&)() is valid. */
8512 }
8514 /* Return true if all copy and move ctor overloads for class TYPE are
8515 trivial and at least one of them is not deleted and, when ACCESS is
8516 set, accessible. Return false otherwise. Set each element of HASCTOR[]
8517 to true when the TYPE has a (not necessarily trivial) default and copy
8518 (or move) ctor, respectively. */
8520 static bool
8522 {
8527 {
8530 /* Skip template constructors. */
8536 /* Skip ctors other than default, copy, and move. */
8552 /* Break early when both properties have been determined. */
8555 }
8558 }
8560 /* Issue a warning on a call to the built-in function FNDECL if it is
8561 a raw memory write whose destination is not an object of (something
8562 like) trivial or standard layout type with a non-deleted assignment
8563 and copy ctor. Detects const correctness violations, corrupting
8564 references, virtual table pointers, and bypassing non-trivial
8565 assignments. */
8567 static void
8570 {
8571 /* Except for bcopy where it's second, the destination pointer is
8572 the first argument for all functions handled here. Compute
8573 the index of the destination and source arguments. */
8583 /* Determine the type of the pointed-to object and whether it's
8584 a complete class type. */
8590 /* Check to see if the raw memory call is made by a non-static member
8591 function with THIS as the destination argument for the destination
8592 type. If so, and if the class has no non-trivial bases or members,
8593 be more permissive. */
8597 {
8602 /* FIXME: The following if statement is overly permissive (see
8603 bug 84851). Remove it in GCC 9. */
8615 }
8617 /* True if the class is trivial. */
8620 /* Set to true if DESTYPE has an accessible copy assignment. */
8622 /* True if all of the class' overloaded copy assignment operators
8623 are all trivial (and not deleted) and at least one of them is
8624 accessible. */
8627 /* Set to true if DESTTYPE has an accessible default and copy ctor,
8628 respectively. */
8631 /* True if all of the class' overloaded copy constructors are all
8632 trivial (and not deleted) and at least one of them is accessible. */
8635 /* Set FLD to the first private/protected member of the class. */
8638 /* The warning format string. */
8640 /* A suggested alternative to offer instead of the raw memory call.
8641 Empty string when none can be come up with. */
8646 {
8649 {
8650 /* Diagnose setting non-copy-assignable or non-trivial types,
8651 or types with a private member, to (potentially) non-zero
8652 bytes. Since the value of the bytes being written is unknown,
8653 suggest using assignment instead (if one exists). Also warn
8654 for writes into objects for which zero-initialization doesn't
8655 mean all bits clear (pointer-to-member data, where null is all
8656 bits set). Since the value being written is (most likely)
8657 non-zero, simply suggest assignment (but not copy assignment). */
8665 {
8668 "%qD writing to an object of type %#qT with "
8671 }
8677 }
8678 /* Fall through. */
8681 /* Similarly to the above, diagnose clearing non-trivial or non-
8682 standard layout objects, or objects of types with no assignmenmt.
8683 Since the value being written is known to be zero, suggest either
8684 copy assignment, copy ctor, or default ctor as an alternative,
8685 depending on what's available. */
8708 /* Determine the type of the source object. */
8712 else
8715 /* Since it's impossible to determine wheter the byte copy is
8716 being used in place of assignment to an existing object or
8717 as a substitute for initialization, assume it's the former.
8718 Determine the best alternative to use instead depending on
8719 what's not deleted. */
8740 srctype))
8741 {
8742 /* Warn when copying into a non-trivial object from an object
8743 of a different type other than void or char. */
8745 "%qD copying an object of non-trivial type "
8748 }
8753 srctype))
8754 {
8757 "%qD copying an object of type %#qT with "
8758 "%qs member %qD from an array of %#qT; use "
8761 }
8763 {
8768 /* Finally, warn on partial copies. */
8769 unsigned HOST_WIDE_INT typesize
8775 "a non-trivial type %#qT leaves %wu "
8778 "a non-trivial type %#qT leaves %wu "
8781 }
8796 {
8800 /* Finally, warn on reallocation into insufficient space. */
8802 "%qD moving an object of non-trivial type "
8805 sz);
8806 }
8811 }
8814 {
8818 else
8821 }
8825 }
8827 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
8828 This function performs no overload resolution, conversion, or other
8829 high-level operations. */
8831 tree
8833 tsubst_flags_t complain)
8834 {
8835 tree fndecl;
8837 /* Remember roughly where this call is. */
8844 /* Check that arguments to builtin functions match the expectations. */
8846 && !processing_template_decl
8849 {
8852 /* We need to take care that values to BUILT_IN_NORMAL
8853 are reduced. */
8860 }
8865 /* 5.2.2/11: If a function call is a prvalue of object type: if the
8866 function call is either the operand of a decltype-specifier or the
8867 right operand of a comma operator that is the operand of a
8868 decltype-specifier, a temporary object is not introduced for the
8869 prvalue. The type of the prvalue may be incomplete. */
8871 {
8877 {
8880 }
8881 }
8883 }
8885 /* Returns the value to use for the in-charge parameter when making a
8886 call to a function with the indicated NAME.
8888 FIXME:Can't we find a neater way to do this mapping? */
8890 tree
8892 {
8894 {
8898 }
8899 else
8900 {
8906 }
8909 }
8911 /* We've built up a constructor call RET. Complain if it delegates to the
8912 constructor we're currently compiling. */
8914 static void
8916 {
8922 }
8924 /* Build a call to a constructor, destructor, or an assignment
8925 operator for INSTANCE, an expression with class type. NAME
8926 indicates the special member function to call; *ARGS are the
8927 arguments. ARGS may be NULL. This may change ARGS. BINFO
8928 indicates the base of INSTANCE that is to be passed as the `this'
8929 parameter to the member function called.
8931 FLAGS are the LOOKUP_* flags to use when processing the call.
8933 If NAME indicates a complete object constructor, INSTANCE may be
8934 NULL_TREE. In this case, the caller will call build_cplus_new to
8935 store the newly constructed object into a VAR_DECL. */
8937 tree
8940 {
8941 tree fns;
8942 /* The type of the subobject to be constructed or destroyed. */
8943 tree class_type;
8945 tree ret;
8953 {
8956 /* Shortcut to avoid lazy destructor declaration. */
8958 }
8961 {
8962 /* Resolve the name. */
8967 }
8973 /* Handle the special case where INSTANCE is NULL_TREE. */
8976 else
8977 {
8978 /* Convert to the base class, if necessary. */
8981 {
8983 /* For constructors and destructors, either the base is
8984 non-virtual, or it is virtual but we are doing the
8985 conversion from a constructor or destructor for the
8986 complete object. In either case, we can convert
8987 statically. */
8989 else
8990 {
8991 /* However, for assignment operators, we must convert
8992 dynamically if the base is virtual. */
8996 }
8997 }
8998 }
9002 /* In C++17, "If the initializer expression is a prvalue and the
9003 cv-unqualified version of the source type is the same class as the class
9004 of the destination, the initializer expression is used to initialize the
9005 destination object." Handle that here to avoid doing overload
9006 resolution. */
9010 {
9020 && (same_type_ignoring_top_level_qualifiers_p
9022 {
9031 /* Avoid change of behavior on Wunused-var-2.C. */
9034 }
9035 }
9039 /* When making a call to a constructor or destructor for a subobject
9040 that uses virtual base classes, pass down a pointer to a VTT for
9041 the subobject. */
9045 {
9046 tree vtt;
9047 tree sub_vtt;
9049 /* If the current function is a complete object constructor
9050 or destructor, then we fetch the VTT directly.
9051 Otherwise, we look it up using the VTT we were given. */
9059 else
9063 {
9066 }
9069 }
9074 complain);
9085 }
9087 /* Return the NAME, as a C string. The NAME indicates a function that
9088 is a member of TYPE. *FREE_P is set to true if the caller must
9089 free the memory returned.
9091 Rather than go through all of this, we should simply set the names
9092 of constructors and destructors appropriately, and dispense with
9093 ctor_identifier, dtor_identifier, etc. */
9097 {
9100 /* Assume that we will not allocate memory. */
9102 /* Constructors and destructors are special. */
9104 {
9105 pretty_name
9107 /* For a destructor, add the '~'. */
9109 {
9111 /* Remember that we need to free the memory allocated. */
9113 }
9114 }
9116 {
9119 TFF_PLAIN_IDENTIFIER),
9120 NULL);
9121 /* Remember that we need to free the memory allocated. */
9123 }
9124 else
9128 }
9130 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
9131 be set, upon return, to the function called. ARGS may be NULL.
9132 This may change ARGS. */
9134 static tree
9138 {
9143 tree optype;
9145 tree name;
9148 tree call;
9149 tree fn;
9152 tree orig_instance;
9153 tree orig_fns;
9159 /* We don't know what function we're going to call, yet. */
9168 {
9172 }
9177 /* Dismantle the baselink to collect all the information we need. */
9185 {
9189 }
9200 /* Under DR 147 A::A() is an invalid constructor call,
9201 not a functional cast. */
9203 {
9215 complain);
9217 }
9220 {
9225 }
9227 /* Process the argument list. */
9229 {
9234 }
9236 /* Consider the object argument to be used even if we end up selecting a
9237 static member function. */
9240 /* Figure out whether to skip the first argument for the error
9241 message we will display to users if an error occurs. We don't
9242 want to display any compiler-generated arguments. The "this"
9243 pointer hasn't been added yet. However, we must remove the VTT
9244 pointer if this is a call to a base-class constructor or
9245 destructor. */
9248 {
9249 /* Callers should explicitly indicate whether they want to ctor
9250 the complete object or just the part without virtual bases. */
9253 /* Remove the VTT pointer, if present. */
9258 /* It's OK to call destructors and constructors on cv-qualified
9259 objects. Therefore, convert the INSTANCE to the unqualified
9260 type, if necessary. */
9262 {
9266 }
9267 }
9268 else
9271 /* For the overload resolution we need to find the actual `this`
9272 that would be captured if the call turns out to be to a
9273 non-static member function. Do not actually capture it at this
9274 point. */
9276 /* Constructors don't use the enclosing 'this'. */
9278 else
9281 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9284 /* The number of arguments artificial parms in ARGS; we subtract one because
9285 there's no 'this' in ARGS. */
9288 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
9289 initializer, not T({ }). */
9293 {
9300 /* If the initializer list has no elements and T is a class type with
9301 a default constructor, the object is value-initialized. Handle
9302 this here so we don't need to handle it wherever we use
9303 build_special_member_call. */
9306 /* For a user-provided default constructor, use the normal
9307 mechanisms so that protected access works. */
9312 /* If BASETYPE is an aggregate, we need to do aggregate
9313 initialization. */
9315 {
9318 }
9321 {
9327 }
9329 /* Otherwise go ahead with overload resolution. */
9334 }
9335 else
9344 {
9346 {
9353 else
9354 {
9359 {
9362 }
9370 }
9372 }
9374 }
9375 else
9376 {
9379 {
9382 tree arglist;
9385 {
9393 else
9399 }
9401 }
9402 else
9403 {
9411 {
9412 /* This is not an error, it is runtime undefined
9413 behavior. */
9422 fn);
9423 }
9428 {
9433 {
9434 /* We captured 'this' in the current lambda now that
9435 we know we really need it. */
9437 }
9439 /* We can't tell until instantiation time whether we can use
9441 else
9442 {
9445 fn);
9447 }
9448 }
9451 {
9452 /* Optimize away vtable lookup if we know that this
9453 function can't be overridden. We need to check if
9454 the context and the type where we found fn are the same,
9455 actually FN might be defined in a different class
9456 type because of a using-declaration. In this case, we
9457 do not want to perform a non-virtual call. */
9459 && same_type_ignoring_top_level_qualifiers_p
9465 /* Now we know what function is being called. */
9468 /* Build the actual CALL_EXPR. */
9470 /* In an expression of the form `a->f()' where `f' turns
9471 out to be a static member function, `a' is
9472 none-the-less evaluated. */
9476 {
9477 /* But avoid the implicit lvalue-rvalue conversion when 'a'
9478 is volatile. */
9483 }
9487 /* An explicit call of the form "x->~X()" has type
9488 "void". However, on platforms where destructors
9489 return "this" (i.e., those where
9490 targetm.cxx.cdtor_returns_this is true), such calls
9491 will appear to have a return value of pointer type
9492 to the low-level call machinery. We do not want to
9493 change the low-level machinery, since we want to be
9494 able to optimize "delete f()" on such platforms as
9495 "operator delete(~X(f()))" (rather than generating
9496 "t = f(), ~X(t), operator delete (t)"). */
9498 }
9499 }
9500 }
9503 {
9509 {
9512 }
9515 call = (build_min_non_dep_call_vec
9519 orig_args));
9524 }
9526 /* Free all the conversions we allocated. */
9533 }
9535 /* Wrapper for above. */
9537 tree
9541 {
9542 tree ret;
9548 }
9550 /* Returns true iff standard conversion sequence ICS1 is a proper
9551 subsequence of ICS2. */
9553 static bool
9555 {
9556 /* We can assume that a conversion of the same code
9557 between the same types indicates a subsequence since we only get
9558 here if the types we are converting from are the same. */
9565 {
9575 /* At this point, ICS1 cannot be a proper subsequence of
9576 ICS2. We can get a USER_CONV when we are comparing the
9577 second standard conversion sequence of two user conversion
9578 sequences. */
9593 }
9594 }
9596 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
9597 be any _TYPE nodes. */
9599 bool
9601 {
9605 /* We only allow proper derivation here. The DERIVED_FROM_P macro
9606 considers every class derived from itself. */
9609 }
9611 /* We build the ICS for an implicit object parameter as a pointer
9612 conversion sequence. However, such a sequence should be compared
9613 as if it were a reference conversion sequence. If ICS is the
9614 implicit conversion sequence for an implicit object parameter,
9615 modify it accordingly. */
9617 static void
9619 {
9621 {
9622 /* [over.match.funcs]
9624 For non-static member functions, the type of the
9625 implicit object parameter is "reference to cv X"
9626 where X is the class of which the function is a
9627 member and cv is the cv-qualification on the member
9628 function declaration. */
9630 tree reference_type;
9632 /* The `this' parameter is a pointer to a class type. Make the
9633 implicit conversion talk about a reference to that same class
9634 type. */
9647 }
9648 }
9650 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
9651 and return the initial reference binding conversion. Otherwise,
9652 leave *ICS unchanged and return NULL. */
9656 {
9658 {
9663 }
9666 }
9668 /* Compare two implicit conversion sequences according to the rules set out in
9669 [over.ics.rank]. Return values:
9671 1: ics1 is better than ics2
9672 -1: ics2 is better than ics1
9673 0: ics1 and ics2 are indistinguishable */
9675 static int
9677 {
9678 tree from_type1;
9679 tree from_type2;
9680 tree to_type1;
9681 tree to_type2;
9688 /* REF_BINDING is nonzero if the result of the conversion sequence
9689 is a reference type. In that case REF_CONV is the reference
9690 binding conversion. */
9694 /* Compare badness before stripping the reference conversion. */
9700 /* Handle implicit object parameters. */
9704 /* Handle reference parameters. */
9708 /* List-initialization sequence L1 is a better conversion sequence than
9709 list-initialization sequence L2 if L1 converts to
9710 std::initializer_list<X> for some X and L2 does not. */
9716 /* [over.ics.rank]
9718 When comparing the basic forms of implicit conversion sequences (as
9719 defined in _over.best.ics_)
9721 --a standard conversion sequence (_over.ics.scs_) is a better
9722 conversion sequence than a user-defined conversion sequence
9723 or an ellipsis conversion sequence, and
9725 --a user-defined conversion sequence (_over.ics.user_) is a
9726 better conversion sequence than an ellipsis conversion sequence
9727 (_over.ics.ellipsis_). */
9728 /* Use BAD_CONVERSION_RANK because we already checked for a badness
9729 mismatch. If both ICS are bad, we try to make a decision based on
9730 what would have happened if they'd been good. This is not an
9731 extension, we'll still give an error when we build up the call; this
9732 just helps us give a more helpful error message. */
9742 /* Both conversions are ellipsis conversions. */
9745 /* User-defined conversion sequence U1 is a better conversion sequence
9746 than another user-defined conversion sequence U2 if they contain the
9747 same user-defined conversion operator or constructor and if the sec-
9748 ond standard conversion sequence of U1 is better than the second
9749 standard conversion sequence of U2. */
9751 /* Handle list-conversion with the same code even though it isn't always
9752 ranked as a user-defined conversion and it doesn't have a second
9753 standard conversion sequence; it will still have the desired effect.
9754 Specifically, we need to do the reference binding comparison at the
9755 end of this function. */
9758 {
9774 {
9779 }
9780 else
9781 {
9782 /* For ambiguous or aggregate conversions, use the target type as
9783 a proxy for the conversion function. */
9786 }
9788 /* We can just fall through here, after setting up
9789 FROM_TYPE1 and FROM_TYPE2. */
9792 }
9793 else
9794 {
9798 /* We're dealing with two standard conversion sequences.
9800 [over.ics.rank]
9802 Standard conversion sequence S1 is a better conversion
9803 sequence than standard conversion sequence S2 if
9805 --S1 is a proper subsequence of S2 (comparing the conversion
9806 sequences in the canonical form defined by _over.ics.scs_,
9807 excluding any Lvalue Transformation; the identity
9808 conversion sequence is considered to be a subsequence of
9809 any non-identity conversion sequence */
9820 }
9822 /* One sequence can only be a subsequence of the other if they start with
9823 the same type. They can start with different types when comparing the
9824 second standard conversion sequence in two user-defined conversion
9825 sequences. */
9827 {
9832 }
9834 /* [over.ics.rank]
9836 Or, if not that,
9838 --the rank of S1 is better than the rank of S2 (by the rules
9839 defined below):
9841 Standard conversion sequences are ordered by their ranks: an Exact
9842 Match is a better conversion than a Promotion, which is a better
9843 conversion than a Conversion.
9845 Two conversion sequences with the same rank are indistinguishable
9846 unless one of the following rules applies:
9848 --A conversion that does not a convert a pointer, pointer to member,
9849 or std::nullptr_t to bool is better than one that does.
9851 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
9852 so that we do not have to check it explicitly. */
9861 /* A conversion from scalar arithmetic type to complex is worse than a
9862 conversion between scalar arithmetic types. */
9869 {
9872 else
9874 }
9880 {
9885 }
9886 /* The rules for pointers to members A::* are just like the rules
9887 for pointers A*, except opposite: if B is derived from A then
9888 A::* converts to B::*, not vice versa. For that reason, we
9889 switch the from_ and to_ variables here. */
9896 {
9901 }
9906 {
9907 /* This was one of the pointer or pointer-like conversions.
9909 [over.ics.rank]
9911 --If class B is derived directly or indirectly from class A,
9912 conversion of B* to A* is better than conversion of B* to
9913 void*, and conversion of A* to void* is better than
9914 conversion of B* to void*. */
9917 {
9919 deref_from_type2))
9922 deref_from_type1))
9924 }
9927 {
9929 {
9931 {
9933 deref_to_type1))
9935 }
9936 /* We know that DEREF_TO_TYPE1 is `void' here. */
9938 deref_to_type2))
9940 }
9941 }
9944 {
9945 /* [over.ics.rank]
9947 --If class B is derived directly or indirectly from class A
9948 and class C is derived directly or indirectly from B,
9950 --conversion of C* to B* is better than conversion of C* to
9951 A*,
9953 --conversion of B* to A* is better than conversion of C* to
9954 A* */
9956 {
9958 deref_to_type2))
9961 deref_to_type1))
9963 }
9965 {
9967 deref_from_type1))
9970 deref_from_type2))
9972 }
9973 }
9974 }
9977 {
9980 /* [over.ics.rank]
9982 --binding of an expression of type C to a reference of type
9983 B& is better than binding an expression of type C to a
9984 reference of type A&
9986 --conversion of C to B is better than conversion of C to A, */
9989 {
9994 }
9995 }
9998 {
10001 /* [over.ics.rank]
10003 --binding of an expression of type B to a reference of type
10004 A& is better than binding an expression of type C to a
10005 reference of type A&,
10007 --conversion of B to A is better than conversion of C to A */
10010 {
10015 }
10016 }
10018 /* [over.ics.rank]
10020 --S1 and S2 differ only in their qualification conversion and yield
10021 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
10022 qualification signature of type T1 is a proper subset of the cv-
10023 qualification signature of type T2 */
10027 {
10031 }
10033 /* [over.ics.rank]
10035 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
10036 to an implicit object parameter of a non-static member function
10037 declared without a ref-qualifier, and either S1 binds an lvalue
10038 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
10039 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
10040 draft standard, 13.3.3.2)
10042 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
10043 types to which the references refer are the same type except for
10044 top-level cv-qualifiers, and the type to which the reference
10045 initialized by S2 refers is more cv-qualified than the type to
10046 which the reference initialized by S1 refers.
10048 DR 1328 [over.match.best]: the context is an initialization by
10049 conversion function for direct reference binding (13.3.1.6) of a
10050 reference to function type, the return type of F1 is the same kind of
10051 reference (i.e. lvalue or rvalue) as the reference being initialized,
10052 and the return type of F2 is not. */
10055 {
10062 {
10066 /* Don't prefer a bad conversion that drops cv-quals to a bad
10067 conversion with the wrong rvalueness. */
10071 }
10074 {
10078 {
10079 /* Prefer the one that drops fewer cv-quals. */
10084 }
10086 }
10087 }
10089 /* Neither conversion sequence is better than the other. */
10091 }
10093 /* The source type for this standard conversion sequence. */
10095 static tree
10097 {
10099 {
10104 }
10106 }
10108 /* Note a warning about preferring WINNER to LOSER. We do this by storing
10109 a pointer to LOSER and re-running joust to produce the warning if WINNER
10110 is actually used. */
10112 static void
10114 {
10120 }
10122 /* Compare two candidates for overloading as described in
10123 [over.match.best]. Return values:
10125 1: cand1 is better than cand2
10126 -1: cand2 is better than cand1
10127 0: cand1 and cand2 are indistinguishable */
10129 static int
10131 tsubst_flags_t complain)
10132 {
10138 /* Candidates that involve bad conversions are always worse than those
10139 that don't. */
10145 /* If we have two pseudo-candidates for conversions to the same type,
10146 or two candidates for the same function, arbitrarily pick one. */
10151 /* Prefer a non-deleted function over an implicitly deleted move
10152 constructor or assignment operator. This differs slightly from the
10153 wording for issue 1402 (which says the move op is ignored by overload
10154 resolution), but this way produces better error messages. */
10158 {
10165 }
10167 /* a viable function F1
10168 is defined to be a better function than another viable function F2 if
10169 for all arguments i, ICSi(F1) is not a worse conversion sequence than
10170 ICSi(F2), and then */
10172 /* for some argument j, ICSj(F1) is a better conversion sequence than
10173 ICSj(F2) */
10175 /* For comparing static and non-static member functions, we ignore
10176 the implicit object parameter of the non-static function. The
10177 standard says to pretend that the static function has an object
10178 parm, but that won't work with operator overloading. */
10181 {
10187 /* We're comparing a near-match list constructor and a near-match
10188 non-list constructor. Just treat them as unordered. */
10195 else
10196 {
10199 }
10200 }
10203 {
10209 {
10211 && warn_sign_promo
10223 {
10230 else
10235 {
10239 }
10240 else
10242 }
10245 {
10248 }
10250 }
10251 }
10253 /* warn about confusing overload resolution for user-defined conversions,
10254 either between a constructor and a conversion op, or between two
10255 conversion ops. */
10260 {
10266 else
10269 /* We don't want to complain about `X::operator T1 ()'
10270 beating `X::operator T2 () const', when T2 is a no less
10271 cv-qualified version of T1. */
10274 {
10279 {
10282 }
10285 }
10286 else
10292 {
10299 {
10301 }
10302 }
10303 else
10305 }
10310 /* DR 495 moved this tiebreaker above the template ones. */
10311 /* or, if not that,
10312 the context is an initialization by user-defined conversion (see
10313 _dcl.init_ and _over.match.user_) and the standard conversion
10314 sequence from the return type of F1 to the destination type (i.e.,
10315 the type of the entity being initialized) is a better conversion
10316 sequence than the standard conversion sequence from the return type
10317 of F2 to the destination type. */
10320 {
10324 }
10326 /* or, if not that,
10327 F1 is a non-template function and F2 is a template function
10328 specialization. */
10335 /* or, if not that,
10336 F1 and F2 are template functions and the function template for F1 is
10337 more specialized than the template for F2 according to the partial
10338 ordering rules. */
10341 {
10342 winner = more_specialized_fn
10345 /* [temp.func.order]: The presence of unused ellipsis and default
10346 arguments has no effect on the partial ordering of function
10347 templates. add_function_candidate() will not have
10348 counted the "this" argument for constructors. */
10352 }
10354 // C++ Concepts
10355 // or, if not that, F1 is more constrained than F2.
10357 {
10361 }
10363 /* F1 is generated from a deduction-guide (13.3.1.8) and F2 is not */
10365 {
10367 /* We distinguish between candidates from an explicit deduction guide and
10368 candidates built from a constructor based on DECL_ARTIFICIAL. */
10375 {
10376 /* Prefer the special copy guide over a declared copy/move
10377 constructor. */
10383 /* Prefer a candidate generated from a non-template constructor. */
10388 }
10389 }
10391 /* F1 is a member of a class D, F2 is a member of a base class B of D, and
10392 for all arguments the corresponding parameters of F1 and F2 have the same
10393 type (CWG 2273/2277). */
10398 {
10412 {
10414 {
10419 }
10422 }
10423 }
10425 /* Check whether we can discard a builtin candidate, either because we
10426 have two identical ones or matching builtin and non-builtin candidates.
10428 (Pedantically in the latter case the builtin which matched the user
10429 function should not be added to the overload set, but we spot it here.
10431 [over.match.oper]
10432 ... the builtin candidates include ...
10433 - do not have the same parameter type list as any non-template
10434 non-member candidate. */
10437 {
10443 {
10445 /* Two built-in candidates; arbitrarily pick one. */
10448 /* cand1 is built-in; prefer cand2. */
10450 else
10451 /* cand2 is built-in; prefer cand1. */
10453 }
10454 }
10456 /* For candidates of a multi-versioned function, make the version with
10457 the highest priority win. This version will be checked for dispatching
10458 first. If this version can be inlined into the caller, the front-end
10459 will simply make a direct call to this function. */
10465 {
10471 /* Check if cand1->fn and cand2->fn are versions of the same function. It
10472 is possible that cand1->fn and cand2->fn are function versions but of
10473 different functions. Check types to see if they are versions of the same
10474 function. */
10477 {
10478 /* Always make the version with the higher priority, more
10479 specialized, win. */
10483 else
10485 }
10486 }
10488 /* If the two function declarations represent the same function (this can
10489 happen with declarations in multiple scopes and arg-dependent lookup),
10490 arbitrarily choose one. But first make sure the default args we're
10491 using match. */
10494 {
10501 {
10502 /* Don't crash if the fn is variadic. */
10507 }
10515 {
10518 {
10520 {
10522 {
10524 "default argument mismatch in "
10526 {
10531 }
10532 }
10533 else
10535 }
10536 else
10539 }
10542 }
10545 }
10547 tweak:
10549 /* Extension: If the worst conversion for one candidate is worse than the
10550 worst conversion for the other, take the first. */
10552 {
10557 {
10562 }
10568 {
10569 /* Don't choose a deleted function over ambiguity. */
10573 {
10575 "ISO C++ says that these are ambiguous, even "
10576 "though the worst conversion for the first is better than "
10580 }
10581 else
10584 }
10585 }
10589 }
10591 /* Given a list of candidates for overloading, find the best one, if any.
10592 This algorithm has a worst case of O(2n) (winner is last), and a best
10593 case of O(n/2) (totally ambiguous); much better than a sorting
10594 algorithm. */
10598 {
10603 /* Walk through the list once, comparing each current champ to the next
10604 candidate, knocking out a candidate or two with each comparison. */
10607 {
10611 else
10612 {
10614 {
10619 }
10620 else
10621 {
10624 }
10627 }
10628 }
10630 /* Make sure the champ is better than all the candidates it hasn't yet
10631 been compared to. */
10634 challenger != champ
10637 {
10641 }
10644 }
10646 /* Returns nonzero if things of type FROM can be converted to TO. */
10648 bool
10650 {
10652 /* implicit_conversion only considers user-defined conversions
10653 if it has an expression for the call argument list. */
10657 }
10659 /* Returns nonzero if things of type FROM can be converted to TO with a
10660 standard conversion. */
10662 bool
10664 {
10666 }
10668 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
10670 bool
10672 tsubst_flags_t complain)
10673 {
10678 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10680 /* We want to discard any access checks done for this test,
10681 as we might not be in the appropriate access context and
10682 we'll do the check again when we actually perform the
10683 conversion. */
10690 /* Discard the access checks now. */
10692 /* Free all the conversions we allocated. */
10696 }
10698 /* Like can_convert_arg, but allows dubious conversions as well. */
10700 bool
10702 tsubst_flags_t complain)
10703 {
10707 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10709 /* Try to perform the conversion. */
10712 /* Free all the conversions we allocated. */
10716 }
10718 /* Convert EXPR to TYPE. Return the converted expression.
10720 Note that we allow bad conversions here because by the time we get to
10721 this point we are committed to doing the conversion. If we end up
10722 doing a bad conversion, convert_like will complain. */
10724 tree
10727 {
10734 else
10740 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10748 {
10750 {
10751 /* If expr has unknown type, then it is an overloaded function.
10752 Call instantiate_type to get good error messages. */
10757 else
10760 }
10762 }
10764 {
10765 /* In a template, we are only concerned about determining the
10766 type of non-dependent expressions, so we do not have to
10767 perform the actual conversion. But for initializers, we
10768 need to be able to perform it at instantiation
10769 (or instantiate_non_dependent_expr) time. */
10773 }
10774 else
10777 /* Free all the conversions we allocated. */
10781 }
10783 tree
10785 {
10787 LOOKUP_IMPLICIT);
10788 }
10790 /* Convert EXPR to TYPE (as a direct-initialization) if that is
10791 permitted. If the conversion is valid, the converted expression is
10792 returned. Otherwise, NULL_TREE is returned, except in the case
10793 that TYPE is a class type; in that case, an error is issued. If
10794 C_CAST_P is true, then this direct-initialization is taking
10795 place as part of a static_cast being attempted as part of a C-style
10796 cast. */
10798 tree
10800 tree expr,
10802 tsubst_flags_t complain)
10803 {
10809 /* [dcl.init]
10811 If the destination type is a (possibly cv-qualified) class type:
10813 -- If the initialization is direct-initialization ...,
10814 constructors are considered. ... If no constructor applies, or
10815 the overload resolution is ambiguous, the initialization is
10816 ill-formed. */
10818 {
10824 }
10826 /* Get the high-water mark for the CONVERSION_OBSTACK. */
10830 c_cast_p,
10835 {
10836 /* In a template, we are only concerned about determining the
10837 type of non-dependent expressions, so we do not have to
10838 perform the actual conversion. But for initializers, we
10839 need to be able to perform it at instantiation
10840 (or instantiate_non_dependent_expr) time. */
10843 }
10844 else
10847 c_cast_p,
10848 complain);
10850 /* Free all the conversions we allocated. */
10854 }
10856 /* When initializing a reference that lasts longer than a full-expression,
10857 this special rule applies:
10859 [class.temporary]
10861 The temporary to which the reference is bound or the temporary
10862 that is the complete object to which the reference is bound
10863 persists for the lifetime of the reference.
10865 The temporaries created during the evaluation of the expression
10866 initializing the reference, except the temporary to which the
10867 reference is bound, are destroyed at the end of the
10868 full-expression in which they are created.
10870 In that case, we store the converted expression into a new
10871 VAR_DECL in a new scope.
10873 However, we want to be careful not to create temporaries when
10874 they are not required. For example, given:
10876 struct B {};
10877 struct D : public B {};
10878 D f();
10879 const B& b = f();
10881 there is no need to copy the return value from "f"; we can just
10882 extend its lifetime. Similarly, given:
10884 struct S {};
10885 struct T { operator S(); };
10886 T t;
10887 const S& s = t;
10889 we can extend the lifetime of the return value of the conversion
10890 operator.
10892 The next several functions are involved in this lifetime extension. */
10894 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
10895 reference is being bound to a temporary. Create and return a new
10896 VAR_DECL with the indicated TYPE; this variable will store the value to
10897 which the reference is bound. */
10899 tree
10901 {
10904 /* Register the variable. */
10907 {
10908 /* Namespace-scope or local static; give it a mangled name. */
10909 /* FIXME share comdat with decl? */
10920 }
10921 else
10922 /* Create a new cleanup level if necessary. */
10926 }
10928 /* EXPR is the initializer for a variable DECL of reference or
10929 std::initializer_list type. Create, push and return a new VAR_DECL
10930 for the initializer so that it will live as long as DECL. Any
10931 cleanup for the new variable is returned through CLEANUP, and the
10932 code to initialize the new variable is returned through INITP. */
10934 static tree
10937 {
10938 tree init;
10939 tree type;
10940 tree var;
10942 /* Create the temporary variable. */
10946 /* If the rvalue is the result of a function call it will be
10947 a TARGET_EXPR. If it is some other construct (such as a
10948 member access expression where the underlying object is
10949 itself the result of a function call), turn it into a
10950 TARGET_EXPR here. It is important that EXPR be a
10951 TARGET_EXPR below since otherwise the INIT_EXPR will
10952 attempt to make a bitwise copy of EXPR to initialize
10953 VAR. */
10959 {
10963 }
10965 /* Recursively extend temps in this initializer. */
10969 /* Any reference temp has a non-trivial initializer. */
10972 /* If the initializer is constant, put it in DECL_INITIAL so we get
10973 static initialization and use in constant expressions. */
10975 /* As in store_init_value. */
10978 {
10980 {
10981 /* 5.19 says that a constant expression can include an
10982 lvalue-rvalue conversion applied to "a glvalue of literal type
10983 that refers to a non-volatile temporary object initialized
10984 with a constant expression". Rather than try to communicate
10985 that this VAR_DECL is a temporary, just mark it constexpr. */
10990 }
10993 }
10994 else
10995 /* Create the INIT_EXPR that will initialize the temporary
10996 variable. */
10999 {
11004 else
11005 {
11009 }
11011 /* We must be careful to destroy the temporary only
11012 after its initialization has taken place. If the
11013 initialization throws an exception, then the
11014 destructor should not be run. We cannot simply
11015 transform INIT into something like:
11017 (INIT, ({ CLEANUP_STMT; }))
11019 because emit_local_var always treats the
11020 initializer as a full-expression. Thus, the
11021 destructor would run too early; it would run at the
11022 end of initializing the reference variable, rather
11023 than at the end of the block enclosing the
11024 reference variable.
11026 The solution is to pass back a cleanup expression
11027 which the caller is responsible for attaching to
11028 the statement tree. */
11029 }
11030 else
11031 {
11034 {
11037 tls_aggregates);
11038 else
11040 static_aggregates);
11041 }
11042 else
11043 /* Check whether the dtor is callable. */
11045 }
11046 /* Avoid -Wunused-variable warning (c++/38958). */
11053 }
11055 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
11056 initializing a variable of that TYPE. */
11058 tree
11061 {
11069 /* Get the high-water mark for the CONVERSION_OBSTACK. */
11075 {
11077 {
11086 else
11090 }
11092 }
11095 /* Perform the conversion. */
11098 /* We gave an error in build_user_type_conversion_1. */
11100 else
11103 /* Free all the conversions we allocated. */
11107 }
11109 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
11110 which is bound either to a reference or a std::initializer_list. */
11112 static tree
11114 {
11119 {
11123 }
11126 /* Deal with binding to a subobject. */
11132 {
11140 }
11142 }
11144 /* INIT is part of the initializer for DECL. If there are any
11145 reference or initializer lists being initialized, extend their
11146 lifetime to match that of DECL. */
11148 tree
11150 {
11156 else
11157 {
11162 {
11164 {
11165 /* The temporary array underlying a std::initializer_list
11166 is handled like a reference temporary. */
11170 }
11171 else
11172 {
11178 }
11182 }
11183 }
11186 }
11188 /* Returns true iff an initializer for TYPE could contain temporaries that
11189 need to be extended because they are bound to references or
11190 std::initializer_list. */
11192 bool
11194 {
11199 {
11206 }
11208 }
11210 /* Returns true iff TYPE is some variant of std::initializer_list. */
11212 bool
11214 {
11219 /* Look through typedefs. */
11224 }
11226 /* Returns true iff DECL is a list constructor: i.e. a constructor which
11227 will accept an argument list of a single std::initializer_list<T>. */
11229 bool
11231 {
11233 tree arg;
11245 /* There are more non-defaulted parms. */
11249 }