| blob | 8d4a9e23a0a51ba95dacaaaa285d6ecb9969b412 |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987-2015 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. */
49 /* The various kinds of conversion. */
52 ck_identity,
53 ck_lvalue,
54 ck_qual,
55 ck_std,
56 ck_ptr,
57 ck_pmem,
58 ck_base,
59 ck_ref_bind,
60 ck_user,
61 ck_ambig,
62 ck_list,
63 ck_aggr,
64 ck_rvalue
65 };
67 /* The rank of the conversion. Order of the enumerals matters; better
68 conversions should come earlier in the list. */
71 cr_identity,
72 cr_exact,
73 cr_promotion,
74 cr_std,
75 cr_pbool,
76 cr_user,
77 cr_ellipsis,
78 cr_bad
79 };
81 /* An implicit conversion sequence, in the sense of [over.best.ics].
82 The first conversion to be performed is at the end of the chain.
83 That conversion is always a cr_identity conversion. */
86 /* The kind of conversion represented by this step. */
87 conversion_kind kind;
88 /* The rank of this conversion. */
89 conversion_rank rank;
93 /* True if this conversion would be permitted with a bending of
94 language standards, e.g. disregarding pointer qualifiers or
95 converting integers to pointers. */
97 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
98 temporary should be created to hold the result of the
99 conversion. */
101 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
102 from a pointer-to-derived to pointer-to-base is being performed. */
104 /* If KIND is ck_ref_bind, true when either an lvalue reference is
105 being bound to an lvalue expression or an rvalue reference is
106 being bound to an rvalue expression. If KIND is ck_rvalue,
107 true when we should treat an lvalue as an rvalue (12.8p33). If
108 KIND is ck_base, always false. */
111 /* The type of the expression resulting from the conversion. */
112 tree type;
114 /* The next conversion in the chain. Since the conversions are
115 arranged from outermost to innermost, the NEXT conversion will
116 actually be performed before this conversion. This variant is
117 used only when KIND is neither ck_identity, ck_ambig nor
118 ck_list. Please use the next_conversion function instead
119 of using this field directly. */
121 /* The expression at the beginning of the conversion chain. This
122 variant is used only if KIND is ck_identity or ck_ambig. */
123 tree expr;
124 /* The array of conversions for an initializer_list, so this
125 variant is used only when KIN D is ck_list. */
128 /* The function candidate corresponding to this conversion
129 sequence. This field is only used if KIND is ck_user. */
131 };
133 #define CONVERSION_RANK(NODE) \
134 ((NODE)->bad_p ? cr_bad \
135 : (NODE)->ellipsis_p ? cr_ellipsis \
136 : (NODE)->user_conv_p ? cr_user \
137 : (NODE)->rank)
139 #define BAD_CONVERSION_RANK(NODE) \
140 ((NODE)->ellipsis_p ? cr_ellipsis \
141 : (NODE)->user_conv_p ? cr_user \
142 : (NODE)->rank)
151 tsubst_flags_t);
155 #define convert_like(CONV, EXPR, COMPLAIN) \
156 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
159 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
160 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
168 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);
203 tsubst_flags_t);
223 tsubst_flags_t);
227 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
228 NAME can take many forms... */
230 bool
232 {
233 /* Just accept something we've already complained about. */
242 {
248 else
250 }
251 else
252 {
253 /* In the case of:
255 template <class T> struct S { ~S(); };
256 int i;
257 i.~S();
259 NAME will be a class template. */
262 }
267 }
269 /* We want the address of a function or method. We avoid creating a
270 pointer-to-member function. */
272 tree
274 {
277 /* We have to do these by hand to avoid real pointer to member
278 functions. */
280 {
282 {
286 complain);
287 }
289 }
290 else
294 }
296 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
297 POINTER_TYPE to those. Note, pointer to member function types
298 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
299 two variants. build_call_a is the primitive taking an array of
300 arguments, while build_call_n is a wrapper that handles varargs. */
302 tree
304 {
307 else
308 {
318 }
319 }
321 /* Update various flags in cfun and the call itself based on what is being
322 called. Split out of build_call_a so that bot_manip can use it too. */
324 void
326 {
330 /* We check both the decl and the type; a function may be known not to
331 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_constraint_failure
428 };
431 /* The index of the argument, 0-based. */
433 /* The actual argument or its type. */
434 tree from;
435 /* The type of the parameter. */
436 tree to_type;
437 };
442 /* Information about an arity mismatch. */
444 /* The expected number of arguments. */
446 /* The actual number of arguments in the call. */
448 /* Whether the call was a varargs call. */
451 /* Information about an argument conversion mismatch. */
453 /* Same, but for bad argument conversions. */
455 /* Information about template unification failures. These are the
456 parameters passed to fn_type_unification. */
458 tree tmpl;
459 tree explicit_targs;
463 tree return_type;
464 unification_kind_t strict;
467 /* Information about template instantiation failures. These are the
468 parameters passed to instantiate_template. */
470 tree tmpl;
471 tree targs;
474 };
477 /* The FUNCTION_DECL that will be called if this candidate is
478 selected by overload resolution. */
479 tree fn;
480 /* If not NULL_TREE, the first argument to use when calling this
481 function. */
482 tree first_arg;
483 /* The rest of the arguments to use when calling this function. If
484 there are no further arguments this may be NULL or it may be an
485 empty vector. */
487 /* The implicit conversion sequences for each of the arguments to
488 FN. */
490 /* The number of implicit conversion sequences. */
492 /* If FN is a user-defined conversion, the standard conversion
493 sequence from the type returned by FN to the desired destination
494 type. */
497 /* If FN is a member function, the binfo indicating the path used to
498 qualify the name of FN at the call site. This path is used to
499 determine whether or not FN is accessible if it is selected by
500 overload resolution. The DECL_CONTEXT of FN will always be a
501 (possibly improper) base of this binfo. */
502 tree access_path;
503 /* If FN is a non-static member function, the binfo indicating the
504 subobject to which the `this' pointer should be converted if FN
505 is selected by overload resolution. The type pointed to by
506 the `this' pointer must correspond to the most derived class
507 indicated by the CONVERSION_PATH. */
508 tree conversion_path;
509 tree template_decl;
510 tree explicit_targs;
515 /* The flags active in add_candidate. */
517 };
519 /* Returns true iff T is a null pointer constant in the sense of
520 [conv.ptr]. */
522 bool
524 {
527 /* [conv.ptr]
529 A null pointer constant is an integral constant expression
530 (_expr.const_) rvalue of integer type that evaluates to zero or
531 an rvalue of type std::nullptr_t. */
536 {
537 /* Core issue 903 says only literal 0 is a null pointer constant. */
543 }
545 {
550 }
553 }
555 /* Returns true iff T is a null member pointer value (4.11). */
557 bool
559 {
568 else
570 }
572 /* Returns nonzero if PARMLIST consists of only default parms,
573 ellipsis, and/or undeduced parameter packs. */
575 bool
577 {
584 }
586 /* Allocate N bytes of memory from the conversion obstack. The memory
587 is zeroed before being returned. */
591 {
594 {
597 }
601 }
603 /* Allocate rejection reasons. */
607 {
612 }
616 {
622 }
626 {
633 }
637 {
644 }
648 {
654 }
658 {
664 }
671 {
678 /* Copy args to our own storage. */
686 }
690 {
692 }
696 {
699 }
701 // Build a constraint failure record, saving information into the
702 // template_instantiation field of the rejection. If FN is not a template
703 // declaration, the TMPL member is the FN declaration and TARGS is empty.
707 {
710 {
713 }
714 else
715 {
718 }
720 }
722 /* Dynamically allocate a conversion. */
726 {
731 }
733 #ifdef ENABLE_CHECKING
735 /* Make sure that all memory on the conversion obstack has been
736 freed. */
738 void
740 {
744 }
748 /* Dynamically allocate an array of N conversions. */
752 {
754 }
758 {
762 /* Note that the caller is responsible for filling in t->cand for
763 user-defined conversions. */
769 {
785 }
791 }
793 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
794 specialization of std::initializer_list<T>, if such a conversion is
795 possible. */
799 {
805 tree val;
807 /* Within a list-initialization we can have more user-defined
808 conversions. */
810 /* But no narrowing conversions. */
813 /* Can't make an array of these types. */
820 {
821 conversion *sub
828 }
836 {
844 }
847 }
849 /* Return the next conversion of the conversion chain (if applicable),
850 or NULL otherwise. Please use this function instead of directly
851 accessing fields of struct conversion. */
855 {
862 }
864 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
865 is a valid aggregate initializer for array type ATYPE. */
867 static bool
869 {
873 {
879 else
881 complain);
884 }
886 }
888 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
889 aggregate class, if such a conversion is possible. */
893 {
899 /* We already called reshape_init in implicit_conversion. */
901 /* The conversions within the init-list aren't affected by the enclosing
902 context; they're always simple copy-initialization. */
906 {
908 tree val;
914 /* Value-initialization of reference is ill-formed. */
916 else
917 {
921 }
927 else
929 complain);
936 }
948 }
950 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
951 array type, if such a conversion is possible. */
955 {
960 tree val;
965 /* We might need to propagate the size from the element to the array. */
970 {
974 }
979 {
980 conversion *sub
992 }
1001 }
1003 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
1004 complex type, if such a conversion is possible. */
1008 tsubst_flags_t complain)
1009 {
1014 tree val;
1025 {
1026 conversion *sub
1038 }
1047 }
1049 /* Build a representation of the identity conversion from EXPR to
1050 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
1054 {
1062 }
1064 /* Converting from EXPR to TYPE was ambiguous in the sense that there
1065 were multiple user-defined conversions to accomplish the job.
1066 Build a conversion that indicates that ambiguity. */
1070 {
1078 }
1080 tree
1082 {
1086 }
1088 /* Returns the standard conversion path (see [conv]) from type FROM to type
1089 TO, if any. For proper handling of null pointer constants, you must
1090 also pass the expression EXPR to convert from. If C_CAST_P is true,
1091 this conversion is coming from a C-style cast. */
1096 {
1100 tree qualified_to;
1104 {
1107 }
1113 {
1115 {
1121 }
1123 {
1124 /* Necessary for eg, TEMPLATE_ID_EXPRs (c++/50961). */
1127 }
1128 }
1135 {
1139 }
1141 {
1143 {
1144 tree bitfield_type;
1147 {
1150 }
1151 }
1155 }
1157 /* Allow conversion between `__complex__' data types. */
1159 {
1160 /* The standard conversion sequence to convert FROM to TO is
1161 the standard conversion sequence to perform componentwise
1162 conversion. */
1167 {
1170 }
1171 else
1175 }
1178 {
1182 }
1184 /* [conv.ptr]
1185 A null pointer constant can be converted to a pointer type; ... A
1186 null pointer constant of integral type can be converted to an
1187 rvalue of type std::nullptr_t. */
1195 {
1196 /* For backwards brain damage compatibility, allow interconversion of
1197 pointers and integers with a pedwarn. */
1200 }
1202 {
1203 /* For backwards brain damage compatibility, allow interconversion of
1204 enums and integers with a pedwarn. */
1207 }
1210 {
1211 tree to_pointee;
1212 tree from_pointee;
1217 ;
1221 {
1223 /* Don't try to apply restrict to void. */
1225 from = build_pointer_type
1228 }
1230 {
1235 && (same_type_ignoring_top_level_qualifiers_p
1238 {
1242 }
1245 }
1248 /* [conv.ptr]
1250 An rvalue of type "pointer to cv D," where D is a
1251 class type, can be converted to an rvalue of type
1252 "pointer to cv B," where B is a base class (clause
1253 _class.derived_) of D. If B is an inaccessible
1254 (clause _class.access_) or ambiguous
1255 (_class.member.lookup_) base class of D, a program
1256 that necessitates this conversion is ill-formed.
1257 Therefore, we use DERIVED_FROM_P, and do not check
1258 access or uniqueness. */
1260 {
1261 from =
1267 }
1270 {
1273 }
1274 else
1275 {
1278 }
1283 /* In a C-style cast, we ignore CV-qualification because we
1284 are allowed to perform a static_cast followed by a
1285 const_cast. */
1290 /* converting from string constant to char *. */
1292 /* Allow conversions among compatible ObjC pointer types (base
1293 conversions have been already handled above). */
1298 {
1301 }
1302 else
1306 }
1308 {
1320 tbase,
1326 }
1328 {
1329 /* [conv.bool]
1331 A prvalue of arithmetic, unscoped enumeration, pointer, or pointer
1332 to member type can be converted to a prvalue of type bool. ...
1333 For direct-initialization (8.5 [dcl.init]), a prvalue of type
1334 std::nullptr_t can be converted to a prvalue of type bool; */
1340 {
1351 }
1354 }
1355 /* We don't check for ENUMERAL_TYPE here because there are no standard
1356 conversions to enum type. */
1357 /* As an extension, allow conversion to complex type. */
1359 {
1366 /* Give this a better rank if it's a promotion. */
1370 }
1376 {
1380 /* The derived-to-base conversion indicates the initialization
1381 of a parameter with base type from an object of a derived
1382 type. A temporary object is created to hold the result of
1383 the conversion unless we're binding directly to a reference. */
1385 }
1386 else
1393 }
1395 /* Returns nonzero if T1 is reference-related to T2. */
1397 bool
1399 {
1406 /* [dcl.init.ref]
1408 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1409 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1410 of T2. */
1414 }
1416 /* Returns nonzero if T1 is reference-compatible with T2. */
1418 static bool
1420 {
1421 /* [dcl.init.ref]
1423 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1424 reference-related to T2 and cv1 is the same cv-qualification as,
1425 or greater cv-qualification than, cv2. */
1428 }
1430 /* A reference of the indicated TYPE is being bound directly to the
1431 expression represented by the implicit conversion sequence CONV.
1432 Return a conversion sequence for this binding. */
1436 {
1437 tree t;
1444 /* [over.ics.rank]
1446 When a parameter of reference type binds directly
1447 (_dcl.init.ref_) to an argument expression, the implicit
1448 conversion sequence is the identity conversion, unless the
1449 argument expression has a type that is a derived class of the
1450 parameter type, in which case the implicit conversion sequence is
1451 a derived-to-base Conversion.
1453 If the parameter binds directly to the result of applying a
1454 conversion function to the argument expression, the implicit
1455 conversion sequence is a user-defined conversion sequence
1456 (_over.ics.user_), with the second standard conversion sequence
1457 either an identity conversion or, if the conversion function
1458 returns an entity of a type that is a derived class of the
1459 parameter type, a derived-to-base conversion. */
1461 {
1462 /* Represent the derived-to-base conversion. */
1464 /* We will actually be binding to the base-class subobject in
1465 the derived class, so we mark this conversion appropriately.
1466 That way, convert_like knows not to generate a temporary. */
1468 }
1470 }
1472 /* Returns the conversion path from type FROM to reference type TO for
1473 purposes of reference binding. For lvalue binding, either pass a
1474 reference type to FROM or an lvalue expression to EXPR. If the
1475 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1476 the conversion returned. If C_CAST_P is true, this
1477 conversion is coming from a C-style cast. */
1481 tsubst_flags_t complain)
1482 {
1486 tree tfrom;
1489 cp_lvalue_kind gl_kind;
1493 {
1498 }
1501 {
1503 /* DR 1288: Otherwise, if the initializer list has a single element
1504 of type E and ... [T's] referenced type is reference-related to E,
1505 the object or reference is initialized from that element... */
1507 {
1513 {
1517 }
1518 }
1519 /* Otherwise, if T is a reference type, a prvalue temporary of the
1520 type referenced by T is copy-list-initialized or
1521 direct-list-initialized, depending on the kind of initialization
1522 for the reference, and the reference is bound to that temporary. */
1525 skip:;
1526 }
1529 {
1534 else
1536 }
1538 {
1541 /* A class prvalue is not a glvalue. */
1543 }
1544 else
1552 /* Figure out whether or not the types are reference-related and
1553 reference compatible. We have to do this after stripping
1554 references from FROM. */
1556 /* If this is a C cast, first convert to an appropriately qualified
1557 type, so that we can later do a const_cast to the desired type. */
1563 /* Directly bind reference when target expression's type is compatible with
1564 the reference and expression is an lvalue. In DR391, the wording in
1565 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1566 const and rvalue references to rvalues of compatible class type.
1567 We should also do direct bindings for non-class xvalues. */
1569 && (gl_kind
1573 {
1574 /* [dcl.init.ref]
1576 If the initializer expression
1578 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1579 is reference-compatible with "cv2 T2,"
1581 the reference is bound directly to the initializer expression
1582 lvalue.
1584 [...]
1585 If the initializer expression is an rvalue, with T2 a class type,
1586 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1587 is bound to the object represented by the rvalue or to a sub-object
1588 within that object. */
1594 /* The top-level caller requested that we pretend that the lvalue
1595 be treated as an rvalue. */
1598 /* Handle rvalue reference to function properly. */
1599 conv->rvaluedness_matches_p
1601 else
1602 conv->rvaluedness_matches_p
1607 /* For the purposes of overload resolution, we ignore the fact
1608 this expression is a bitfield or packed field. (In particular,
1609 [over.ics.ref] says specifically that a function with a
1610 non-const reference parameter is viable even if the
1611 argument is a bitfield.)
1613 However, when we actually call the function we must create
1614 a temporary to which to bind the reference. If the
1615 reference is volatile, or isn't const, then we cannot make
1616 a temporary, so we just issue an error when the conversion
1617 actually occurs. */
1620 /* Don't allow binding of lvalues (other than function lvalues) to
1621 rvalue references. */
1627 /* Nor the reverse. */
1638 }
1639 /* [class.conv.fct] A conversion function is never used to convert a
1640 (possibly cv-qualified) object to the (possibly cv-qualified) same
1641 object type (or a reference to it), to a (possibly cv-qualified) base
1642 class of that type (or a reference to it).... */
1645 {
1646 /* [dcl.init.ref]
1648 If the initializer expression
1650 -- has a class type (i.e., T2 is a class type) can be
1651 implicitly converted to an lvalue of type "cv3 T3," where
1652 "cv1 T1" is reference-compatible with "cv3 T3". (this
1653 conversion is selected by enumerating the applicable
1654 conversion functions (_over.match.ref_) and choosing the
1655 best one through overload resolution. (_over.match_).
1657 the reference is bound to the lvalue result of the conversion
1658 in the second case. */
1660 complain);
1663 }
1665 /* From this point on, we conceptually need temporaries, even if we
1666 elide them. Only the cases above are "direct bindings". */
1670 /* [over.ics.rank]
1672 When a parameter of reference type is not bound directly to an
1673 argument expression, the conversion sequence is the one required
1674 to convert the argument expression to the underlying type of the
1675 reference according to _over.best.ics_. Conceptually, this
1676 conversion sequence corresponds to copy-initializing a temporary
1677 of the underlying type with the argument expression. Any
1678 difference in top-level cv-qualification is subsumed by the
1679 initialization itself and does not constitute a conversion. */
1681 /* [dcl.init.ref]
1683 Otherwise, the reference shall be an lvalue reference to a
1684 non-volatile const type, or the reference shall be an rvalue
1685 reference.
1687 We try below to treat this as a bad conversion to improve diagnostics,
1688 but if TO is an incomplete class, we need to reject this conversion
1689 now to avoid unnecessary instantiation. */
1694 /* We're generating a temporary now, but don't bind any more in the
1695 conversion (specifically, don't slice the temporary returned by a
1696 conversion operator). */
1699 /* Core issue 899: When [copy-]initializing a temporary to be bound
1700 to the first parameter of a copy constructor (12.8) called with
1701 a single argument in the context of direct-initialization,
1702 explicit conversion functions are also considered.
1704 So don't set LOOKUP_ONLYCONVERTING in that case. */
1715 {
1716 /* If initializing the temporary used a conversion function,
1717 recalculate the second conversion sequence. */
1721 {
1724 conversion *new_second
1730 }
1731 }
1734 /* This reference binding, unlike those above, requires the
1735 creation of a temporary. */
1739 /* [dcl.init.ref]
1741 Otherwise, the reference shall be an lvalue reference to a
1742 non-volatile const type, or the reference shall be an rvalue
1743 reference. */
1747 /* [dcl.init.ref]
1749 Otherwise, a temporary of type "cv1 T1" is created and
1750 initialized from the initializer expression using the rules for a
1751 non-reference copy initialization. If T1 is reference-related to
1752 T2, cv1 must be the same cv-qualification as, or greater
1753 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1758 }
1760 /* Returns the implicit conversion sequence (see [over.ics]) from type
1761 FROM to type TO. The optional expression EXPR may affect the
1762 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1763 true, this conversion is coming from a C-style cast. */
1768 {
1775 /* Other flags only apply to the primary function in overload
1776 resolution, or after we've chosen one. */
1781 /* FIXME: actually we don't want warnings either, but we can't just
1782 have 'complain &= ~(tf_warning|tf_error)' because it would cause
1783 the regression of, eg, g++.old-deja/g++.benjamin/16077.C.
1784 We really ought not to issue that warning until we've committed
1785 to that conversion. */
1788 /* Call reshape_init early to remove redundant braces. */
1793 {
1798 }
1802 else
1809 {
1813 /* As an extension, allow list-initialization of _Complex. */
1815 {
1819 }
1821 /* Allow conversion from an initializer-list with one element to a
1822 scalar type. */
1824 {
1826 tree elt;
1832 else
1838 {
1841 /* Too many levels of braces, i.e. '{{1}}'. */
1844 }
1845 }
1848 }
1854 {
1866 /* We used to try to bind a reference to a temporary here, but that
1867 is now handled after the recursive call to this function at the end
1868 of reference_binding. */
1870 }
1873 }
1875 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1876 functions. ARGS will not be changed until a single candidate is
1877 selected. */
1886 {
1904 }
1906 /* Return the number of remaining arguments in the parameter list
1907 beginning with ARG. */
1909 static int
1911 {
1916 n++;
1919 }
1921 /* Create an overload candidate for the function or method FN called
1922 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1923 FLAGS is passed on to implicit_conversion.
1925 This does not change ARGS.
1927 CTYPE, if non-NULL, is the type we want to pretend this function
1928 comes from for purposes of overload resolution. */
1935 tsubst_flags_t complain)
1936 {
1940 tree parmnode;
1946 /* At this point we should not see any functions which haven't been
1947 explicitly declared, except for friend functions which will have
1948 been found using argument dependent lookup. */
1951 /* The `this', `in_chrg' and VTT arguments to constructors are not
1952 considered in overload resolution. */
1954 {
1958 {
1961 }
1962 }
1963 else
1969 /* 13.3.2 - Viable functions [over.match.viable]
1970 First, to be a viable function, a candidate function shall have enough
1971 parameters to agree in number with the arguments in the list.
1973 We need to check this first; otherwise, checking the ICSes might cause
1974 us to produce an ill-formed template instantiation. */
1978 {
1982 }
1986 {
1990 }
1992 /* Second, for a function to be viable, its constraints must be
1993 satisfied. */
1996 {
1999 }
2001 /* When looking for a function from a subobject from an implicit
2002 copy/move constructor/operator=, don't consider anything that takes (a
2003 reference to) an unrelated type. See c++/44909 and core 1092. */
2005 {
2011 else
2014 {
2017 ctype))
2019 }
2021 /* This only applies at the top level. */
2023 }
2028 /* Third, for F to be a viable function, there shall exist for each
2029 argument an implicit conversion sequence that converts that argument
2030 to the corresponding parameter of F. */
2035 {
2037 tree arg;
2046 else
2055 {
2061 /* The type of the implicit object parameter ('this') for
2062 overload resolution is not always the same as for the
2063 function itself; conversion functions are considered to
2064 be members of the class being converted, and functions
2065 introduced by a using-declaration are considered to be
2066 members of the class that uses them.
2068 Since build_over_call ignores the ICS for the `this'
2069 parameter, we can just change the parm type. */
2071 {
2072 parmtype = cp_build_qualified_type
2075 {
2076 /* If the function has a ref-qualifier, the implicit
2077 object parameter has reference type. */
2080 /* The special handling of 'this' conversions in compare_ics
2081 does not apply if there is a ref-qualifier. */
2083 }
2084 else
2085 {
2089 }
2090 }
2092 /* Core issue 899: When [copy-]initializing a temporary to be bound
2093 to the first parameter of a copy constructor (12.8) called with
2094 a single argument in the context of direct-initialization,
2095 explicit conversion functions are also considered.
2097 So set LOOKUP_COPY_PARM to let reference_binding know that
2098 it's being called in that context. We generalize the above
2099 to handle move constructors and template constructors as well;
2100 the standardese should soon be updated similarly. */
2104 && (same_type_ignoring_top_level_qualifiers_p
2106 {
2109 /* We allow user-defined conversions within init-lists, but
2110 don't list-initialize the copy parm, as that would mean
2111 using two levels of braces for the same type. */
2115 }
2116 else
2122 }
2123 else
2124 {
2128 }
2135 {
2139 }
2142 {
2145 }
2146 }
2148 out:
2151 }
2153 /* Create an overload candidate for the conversion function FN which will
2154 be invoked for expression OBJ, producing a pointer-to-function which
2155 will in turn be called with the argument list FIRST_ARG/ARGLIST,
2156 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
2157 passed on to implicit_conversion.
2159 Actually, we don't really care about FN; we care about the type it
2160 converts to. There may be multiple conversion functions that will
2161 convert to that type, and we rely on build_user_type_conversion_1 to
2162 choose the best one; so when we create our candidate, we record the type
2163 instead of the function. */
2169 tsubst_flags_t complain)
2170 {
2188 /* Don't bother looking up the same type twice. */
2193 {
2201 else
2206 {
2210 }
2214 {
2218 }
2219 else
2220 {
2224 }
2231 {
2234 }
2241 }
2245 {
2249 }
2253 }
2255 static void
2259 {
2273 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2274 conversion ops are allowed. We handle that here by just checking for
2275 boolean_type_node because other operators don't ask for it. COND_EXPR
2276 also does contextual conversion to bool for the first operand, but we
2277 handle that in build_conditional_expr, and type1 here is operand 2. */
2282 {
2289 {
2291 /* We need something for printing the candidate. */
2295 }
2297 {
2301 }
2303 }
2305 /* For COND_EXPR we rearranged the arguments; undo that now. */
2307 {
2312 complain);
2315 else
2316 {
2319 boolean_type_node);
2320 }
2321 }
2328 }
2330 static bool
2332 {
2334 }
2336 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2338 static bool
2340 {
2341 /* [over.built]
2343 In this section, the term promoted integral type is used to refer
2344 to those integral types which are preserved by integral promotion
2345 (including e.g. int and long but excluding e.g. char).
2346 Similarly, the term promoted arithmetic type refers to promoted
2347 integral types plus floating types. */
2351 }
2353 /* Create any builtin operator overload candidates for the operator in
2354 question given the converted operand types TYPE1 and TYPE2. The other
2355 args are passed through from add_builtin_candidates to
2356 build_builtin_candidate.
2358 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2359 If CODE is requires candidates operands of the same type of the kind
2360 of which TYPE1 and TYPE2 are, we add both candidates
2361 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2363 static void
2367 tsubst_flags_t complain)
2368 {
2370 {
2378 }
2381 {
2383 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2384 and VQ is either volatile or empty, there exist candidate operator
2385 functions of the form
2386 VQ T& operator++(VQ T&);
2387 T operator++(VQ T&, int);
2388 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2389 type other than bool, and VQ is either volatile or empty, there exist
2390 candidate operator functions of the form
2391 VQ T& operator--(VQ T&);
2392 T operator--(VQ T&, int);
2393 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2394 complete object type, and VQ is either volatile or empty, there exist
2395 candidate operator functions of the form
2396 T*VQ& operator++(T*VQ&);
2397 T*VQ& operator--(T*VQ&);
2398 T* operator++(T*VQ&, int);
2399 T* operator--(T*VQ&, int); */
2408 {
2411 }
2414 /* 7 For every cv-qualified or cv-unqualified object type T, there
2415 exist candidate operator functions of the form
2417 T& operator*(T*);
2419 8 For every function type T, there exist candidate operator functions of
2420 the form
2421 T& operator*(T*); */
2430 /* 9 For every type T, there exist candidate operator functions of the form
2431 T* operator+(T*);
2433 10For every promoted arithmetic type T, there exist candidate operator
2434 functions of the form
2435 T operator+(T);
2436 T operator-(T); */
2446 /* 11For every promoted integral type T, there exist candidate operator
2447 functions of the form
2448 T operator~(T); */
2455 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2456 is the same type as C2 or is a derived class of C2, T is a complete
2457 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2458 there exist candidate operator functions of the form
2459 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2460 where CV12 is the union of CV1 and CV2. */
2464 {
2472 }
2475 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2476 didate operator functions of the form
2477 LR operator*(L, R);
2478 LR operator/(L, R);
2479 LR operator+(L, R);
2480 LR operator-(L, R);
2481 bool operator<(L, R);
2482 bool operator>(L, R);
2483 bool operator<=(L, R);
2484 bool operator>=(L, R);
2485 bool operator==(L, R);
2486 bool operator!=(L, R);
2487 where LR is the result of the usual arithmetic conversions between
2488 types L and R.
2490 14For every pair of types T and I, where T is a cv-qualified or cv-
2491 unqualified complete object type and I is a promoted integral type,
2492 there exist candidate operator functions of the form
2493 T* operator+(T*, I);
2494 T& operator[](T*, I);
2495 T* operator-(T*, I);
2496 T* operator+(I, T*);
2497 T& operator[](I, T*);
2499 15For every T, where T is a pointer to complete object type, there exist
2500 candidate operator functions of the form112)
2501 ptrdiff_t operator-(T, T);
2503 16For every pointer or enumeration type T, there exist candidate operator
2504 functions of the form
2505 bool operator<(T, T);
2506 bool operator>(T, T);
2507 bool operator<=(T, T);
2508 bool operator>=(T, T);
2509 bool operator==(T, T);
2510 bool operator!=(T, T);
2512 17For every pointer to member type T, there exist candidate operator
2513 functions of the form
2514 bool operator==(T, T);
2515 bool operator!=(T, T); */
2522 {
2525 }
2538 {
2541 }
2543 {
2546 }
2547 /* Fall through. */
2563 {
2566 }
2569 {
2572 }
2580 {
2583 }
2585 {
2588 }
2591 /* 18For every pair of promoted integral types L and R, there exist candi-
2592 date operator functions of the form
2593 LR operator%(L, R);
2594 LR operator&(L, R);
2595 LR operator^(L, R);
2596 LR operator|(L, R);
2597 L operator<<(L, R);
2598 L operator>>(L, R);
2599 where LR is the result of the usual arithmetic conversions between
2600 types L and R. */
2608 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2612 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2613 type, VQ is either volatile or empty, and R is a promoted arithmetic
2614 type, there exist candidate operator functions of the form
2615 VQ L& operator=(VQ L&, R);
2616 VQ L& operator*=(VQ L&, R);
2617 VQ L& operator/=(VQ L&, R);
2618 VQ L& operator+=(VQ L&, R);
2619 VQ L& operator-=(VQ L&, R);
2621 20For every pair T, VQ), where T is any type and VQ is either volatile
2622 or empty, there exist candidate operator functions of the form
2623 T*VQ& operator=(T*VQ&, T*);
2625 21For every pair T, VQ), where T is a pointer to member type and VQ is
2626 either volatile or empty, there exist candidate operator functions of
2627 the form
2628 VQ T& operator=(VQ T&, T);
2630 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2631 unqualified complete object type, VQ is either volatile or empty, and
2632 I is a promoted integral type, there exist candidate operator func-
2633 tions of the form
2634 T*VQ& operator+=(T*VQ&, I);
2635 T*VQ& operator-=(T*VQ&, I);
2637 23For every triple L, VQ, R), where L is an integral or enumeration
2638 type, VQ is either volatile or empty, and R is a promoted integral
2639 type, there exist candidate operator functions of the form
2641 VQ L& operator%=(VQ L&, R);
2642 VQ L& operator<<=(VQ L&, R);
2643 VQ L& operator>>=(VQ L&, R);
2644 VQ L& operator&=(VQ L&, R);
2645 VQ L& operator^=(VQ L&, R);
2646 VQ L& operator|=(VQ L&, R); */
2650 {
2654 {
2657 }
2670 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2683 {
2686 }
2691 }
2696 /* [over.built]
2698 For every pair of promoted arithmetic types L and R, there
2699 exist candidate operator functions of the form
2701 LR operator?(bool, L, R);
2703 where LR is the result of the usual arithmetic conversions
2704 between types L and R.
2706 For every type T, where T is a pointer or pointer-to-member
2707 type, there exist candidate operator functions of the form T
2708 operator?(bool, T, T); */
2712 /* That's OK. */
2715 /* Otherwise, the types should be pointers. */
2719 /* We don't check that the two types are the same; the logic
2720 below will actually create two candidates; one in which both
2721 parameter types are TYPE1, and one in which both parameter
2722 types are TYPE2. */
2733 }
2735 /* Make sure we don't create builtin candidates with dependent types. */
2739 {
2740 /* Try to recover if one of the types is non-dependent. But if
2741 there's only one type, there's nothing we can do. */
2744 /* And we lose if both are dependent. */
2747 /* Or if they have different forms. */
2755 }
2757 /* If we're dealing with two pointer types or two enumeral types,
2758 we need candidates for both of them. */
2767 {
2769 {
2771 error_mark_node,
2772 error_mark_node,
2773 CPO_CONVERSION,
2774 tf_none);
2776 {
2777 build_builtin_candidate
2781 }
2782 }
2784 build_builtin_candidate
2786 build_builtin_candidate
2789 }
2791 build_builtin_candidate
2793 }
2795 tree
2797 {
2803 }
2805 /* There are three conditions of builtin candidates:
2807 1) bool-taking candidates. These are the same regardless of the input.
2808 2) pointer-pair taking candidates. These are generated for each type
2809 one of the input types converts to.
2810 3) arithmetic candidates. According to the standard, we should generate
2811 all of these, but I'm trying not to...
2813 Here we generate a superset of the possible candidates for this particular
2814 case. That is a subset of the full set the standard defines, plus some
2815 other cases which the standard disallows. add_builtin_candidate will
2816 filter out the invalid set. */
2818 static void
2822 {
2826 /* TYPES[i] is the set of possible builtin-operator parameter types
2827 we will consider for the Ith argument. */
2832 {
2835 else
2837 }
2840 {
2841 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2842 and VQ is either volatile or empty, there exist candidate operator
2843 functions of the form
2844 VQ T& operator++(VQ T&); */
2854 /* 24There also exist candidate operator functions of the form
2855 bool operator!(bool);
2856 bool operator&&(bool, bool);
2857 bool operator||(bool, bool); */
2860 build_builtin_candidate
2867 build_builtin_candidate
2885 /* Fall through. */
2889 }
2895 {
2897 ;
2899 {
2900 tree convs;
2908 {
2913 }
2919 {
2932 {
2938 }
2942 }
2943 }
2944 else
2945 {
2950 {
2956 }
2958 }
2959 }
2961 /* Run through the possible parameter types of both arguments,
2962 creating candidates with those parameter types. */
2964 {
2966 tree u;
2970 add_builtin_candidate
2973 else
2974 add_builtin_candidate
2977 }
2981 }
2984 /* If TMPL can be successfully instantiated as indicated by
2985 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2987 TMPL is the template. EXPLICIT_TARGS are any explicit template
2988 arguments. ARGLIST is the arguments provided at the call-site.
2989 This does not change ARGLIST. The RETURN_TYPE is the desired type
2990 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2991 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2992 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
3000 tsubst_flags_t complain)
3001 {
3011 tree arg;
3013 tree fn;
3017 /* We don't do deduction on the in-charge parameter, the VTT
3018 parameter or 'this'. */
3020 {
3023 else
3025 }
3030 {
3033 else
3035 }
3045 {
3048 }
3052 {
3055 }
3060 args_without_in_chrg,
3061 nargs_without_in_chrg,
3066 {
3067 /* Don't repeat unification later if it already resulted in errors. */
3071 nargs_without_in_chrg,
3073 else
3076 }
3078 /* In [class.copy]:
3080 A member function template is never instantiated to perform the
3081 copy of a class object to an object of its class type.
3083 It's a little unclear what this means; the standard explicitly
3084 does allow a template to be used to copy a class. For example,
3085 in:
3087 struct A {
3088 A(A&);
3089 template <class T> A(const T&);
3090 };
3091 const A f ();
3092 void g () { A a (f ()); }
3094 the member template will be used to make the copy. The section
3095 quoted above appears in the paragraph that forbids constructors
3096 whose only parameter is (a possibly cv-qualified variant of) the
3097 class type, and a logical interpretation is that the intent was
3098 to forbid the instantiation of member templates which would then
3099 have that form. */
3101 {
3104 ctype))
3105 {
3108 }
3109 }
3112 /* Aha, this is a conversion function. */
3115 else
3120 /* This situation can occur if a member template of a template
3121 class is specialized. Then, instantiate_template might return
3122 an instantiation of the specialization, in which case the
3123 DECL_TI_TEMPLATE field will point at the original
3124 specialization. For example:
3126 template <class T> struct S { template <class U> void f(U);
3127 template <> void f(int) {}; };
3128 S<double> sd;
3129 sd.f(3);
3131 Here, TMPL will be template <class U> S<double>::f(U).
3132 And, instantiate template will give us the specialization
3133 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
3134 for this will point at template <class T> template <> S<T>::f(int),
3135 so that we can find the definition. For the purposes of
3136 overload resolution, however, we want the original TMPL. */
3138 else
3143 fail:
3146 }
3155 {
3156 return
3161 }
3170 {
3171 return
3175 complain);
3176 }
3178 /* The CANDS are the set of candidates that were considered for
3179 overload resolution. Return the set of viable candidates, or CANDS
3180 if none are viable. If any of the candidates were viable, set
3181 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
3182 considered viable only if it is strictly viable. */
3188 {
3194 /* Be strict inside templates, since build_over_call won't actually
3195 do the conversions to get pedwarns. */
3205 {
3209 {
3210 /* Be strict in the presence of a viable candidate. Also if
3211 there are template candidates, so that we get deduction errors
3212 for them instead of silently preferring a bad conversion. */
3215 {
3216 /* Put any spliced near matches back onto the main list so
3217 that we see them if there is no strict match. */
3223 }
3224 }
3227 {
3235 }
3236 else
3238 }
3241 }
3243 static bool
3245 {
3250 }
3252 /* OBJ is being used in an expression like "OBJ.f (...)". In other
3253 words, it is about to become the "this" pointer for a member
3254 function call. Take the address of the object. */
3256 static tree
3258 {
3259 /* In a template, we are only concerned about the type of the
3260 expression, so we can take a shortcut. */
3265 }
3267 /* Returns true iff functions are equivalent. Equivalent functions are
3268 not '==' only if one is a function-local extern function or if
3269 both are extern "C". */
3273 {
3282 }
3284 /* Print information about a candidate being rejected due to INFO. */
3286 static void
3288 {
3293 {
3294 /* Conversion of implicit `this' argument failed. */
3296 /* A bad conversion for 'this' must be discarding cv-quals. */
3299 from);
3300 else
3304 }
3306 {
3311 tf_warning_or_error);
3312 }
3314 /* Conversion of conversion function return value failed. */
3317 else
3320 }
3322 /* Print information about a candidate with WANT parameters and we found
3323 HAVE. */
3325 static void
3327 {
3332 }
3334 /* Print information about one overload candidate CANDIDATE. MSGSTR
3335 is the text to print before the candidate itself.
3337 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
3338 to have been run through gettext by the caller. This wart makes
3339 life simpler in print_z_candidates and for the translators. */
3341 static void
3344 {
3351 {
3362 else
3365 }
3372 else
3374 /* Give the user some information about why this candidate failed. */
3376 {
3380 {
3393 "cannot be converted to %qT with a qualification "
3399 "conversion function specialization to %qT is not an "
3404 /* We use template_unification_error_rejection if unification caused
3405 actual non-SFINAE errors, in which case we don't need to repeat
3406 them here. */
3408 {
3412 }
3413 /* Re-run template unification with diagnostics. */
3417 (make_tree_vec
3428 " a constructor taking a single argument of its own "
3432 {
3436 }
3440 /* This candidate didn't have any issues or we failed to
3441 handle a particular code. Either way... */
3443 }
3444 }
3445 }
3447 static void
3449 {
3456 /* Remove non-viable deleted candidates. */
3459 {
3464 else
3466 }
3467 /* ...if there are any non-deleted ones. */
3471 /* There may be duplicates in the set of candidates. We put off
3472 checking this condition as long as possible, since we have no way
3473 to eliminate duplicates from a set of functions in less than n^2
3474 time. Now we are about to emit an error message, so it is more
3475 permissible to go slowly. */
3477 {
3479 /* Skip builtin candidates and conversion functions. */
3484 {
3488 else
3490 }
3491 }
3495 }
3497 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3498 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3499 the result of the conversion function to convert it to the final
3500 desired type. Merge the two sequences into a single sequence,
3501 and return the merged sequence. */
3505 {
3511 /* Find the end of the second conversion sequence. */
3513 {
3514 /* The entire sequence is a user-conversion sequence. */
3518 }
3520 /* Replace the identity conversion with the user conversion
3521 sequence. */
3525 }
3527 /* Handle overload resolution for initializing an object of class type from
3528 an initializer list. First we look for a suitable constructor that
3529 takes a std::initializer_list; if we don't find one, we then look for a
3530 non-list constructor.
3532 Parameters are as for add_candidates, except that the arguments are in
3533 the form of a CONSTRUCTOR (the initializer list) rather than a vector, and
3534 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3536 static void
3543 tsubst_flags_t complain)
3544 {
3549 /* We're looking for a ctor for list-initialization. */
3551 /* And we don't allow narrowing conversions. We also use this flag to
3552 avoid the copy constructor call for copy-list-initialization. */
3555 /* Always use the default constructor if the list is empty (DR 990). */
3558 ;
3559 /* If the class has a list ctor, try passing the list as a single
3560 argument first, but only consider list ctors. */
3562 {
3570 }
3574 /* We aren't looking for list-ctors anymore. */
3576 /* We allow more user-defined conversions within an init-list. */
3582 }
3584 /* Returns the best overload candidate to perform the requested
3585 conversion. This function is used for three the overloading situations
3586 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3587 If TOTYPE is a REFERENCE_TYPE, we're trying to find a direct binding as
3588 per [dcl.init.ref], so we ignore temporary bindings. */
3592 tsubst_flags_t complain)
3593 {
3595 tree fromtype;
3609 /* We represent conversion within a hierarchy using RVALUE_CONV and
3610 BASE_CONV, as specified by [over.best.ics]; these become plain
3611 constructor calls, as specified in [dcl.init]. */
3616 /* Use lookup_fnfields_slot instead of lookup_fnfields to avoid
3617 creating a garbage BASELINK; constructors can't be inherited. */
3621 {
3626 {
3627 /* [class.conv.fct] A conversion function is never used to
3628 convert a (possibly cv-qualified) object to the (possibly
3629 cv-qualified) same object type (or a reference to it), to a
3630 (possibly cv-qualified) base class of that type (or a
3631 reference to it)... */
3632 }
3633 else
3635 }
3642 /* It's OK to bind a temporary for converting constructor arguments, but
3643 not in converting the return value of a conversion operator. */
3649 {
3654 /* We should never try to call the abstract or base constructor
3655 from here. */
3660 {
3661 /* List-initialization. */
3665 }
3666 else
3667 {
3672 }
3675 {
3678 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3679 set, then this is copy-initialization. In that case, "The
3680 result of the call is then used to direct-initialize the
3681 object that is the destination of the copy-initialization."
3682 [dcl.init]
3684 We represent this in the conversion sequence with an
3685 rvalue conversion, which means a constructor call. */
3688 cand->second_conv
3690 }
3691 }
3697 {
3701 /* If we are called to convert to a reference type, we are trying to
3702 find a direct binding, so don't even consider temporaries. If
3703 we don't find a direct binding, the caller will try again to
3704 look for a temporary binding. */
3715 {
3717 conversion *ics
3719 rettype,
3722 complain);
3724 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3725 copy-initialization. In that case, "The result of the
3726 call is then used to direct-initialize the object that is
3727 the destination of the copy-initialization." [dcl.init]
3729 We represent this in the conversion sequence with an
3730 rvalue conversion, which means a constructor call. But
3731 don't add a second rvalue conversion if there's already
3732 one there. Which there really shouldn't be, but it's
3733 harmless since we'd add it here anyway. */
3741 {
3745 }
3748 {
3749 /* 13.3.1.5: For direct-initialization, those explicit
3750 conversion functions that are not hidden within S and
3751 yield type T or a type that can be converted to type T
3752 with a qualification conversion (4.4) are also candidate
3753 functions. */
3754 /* 13.3.1.6 doesn't have a parallel restriction, but it should;
3755 I've raised this issue with the committee. --jason 9/2011 */
3758 }
3760 {
3762 cand->reason
3765 }
3768 {
3769 /* 13.3.3.1.2: If the user-defined conversion is specified by
3770 a specialization of a conversion function template, the
3771 second standard conversion sequence shall have exact match
3772 rank. */
3775 }
3776 }
3777 }
3781 {
3785 }
3789 {
3791 {
3795 }
3802 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3803 ambiguous conversion is no worse than another user-defined
3804 conversion. */
3807 }
3809 tree convtype;
3813 /* DR 5: [in the first step of copy-initialization]...if the function
3814 is a constructor, the call initializes a temporary of the
3815 cv-unqualified version of the destination type. */
3817 else
3819 /* Build the user conversion sequence. */
3820 conv = build_conv
3822 convtype,
3828 /* Remember that this was a list-initialization. */
3832 /* Combine it with the second conversion sequence. */
3837 }
3839 /* Wrapper for above. */
3841 tree
3843 tsubst_flags_t complain)
3844 {
3846 tree ret;
3852 {
3855 else
3856 {
3859 }
3860 }
3861 else
3866 }
3868 /* Subroutine of convert_nontype_argument.
3870 EXPR is an argument for a template non-type parameter of integral or
3871 enumeration type. Do any necessary conversions (that are permitted for
3872 non-type arguments) to convert it to the parameter type.
3874 If conversion is successful, returns the converted expression;
3875 otherwise, returns error_mark_node. */
3877 tree
3879 {
3882 tree t;
3890 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3897 /* for a non-type template-parameter of integral or
3898 enumeration type, integral promotions (4.5) and integral
3899 conversions (4.7) are applied. */
3900 /* It should be sufficient to check the outermost conversion step, since
3901 there are no qualification conversions to integer type. */
3904 {
3905 /* A conversion function is OK. If it isn't constexpr, we'll
3906 complain later that the argument isn't constant. */
3908 /* The lvalue-to-rvalue conversion is OK. */
3921 /* and fall through. */
3926 }
3930 else
3933 /* Free all the conversions we allocated. */
3937 }
3939 /* Do any initial processing on the arguments to a function call. */
3943 {
3945 tree arg;
3948 {
3952 {
3956 }
3959 }
3961 }
3963 /* Perform overload resolution on FN, which is called with the ARGS.
3965 Return the candidate function selected by overload resolution, or
3966 NULL if the event that overload resolution failed. In the case
3967 that overload resolution fails, *CANDIDATES will be the set of
3968 candidates considered, and ANY_VIABLE_P will be set to true or
3969 false to indicate whether or not any of the candidates were
3970 viable.
3972 The ARGS should already have gone through RESOLVE_ARGS before this
3973 function is called. */
3980 {
3982 tree explicit_targs;
3993 /* Check FN. */
4000 {
4004 }
4006 /* Add the various candidate functions. */
4011 LOOKUP_NORMAL,
4017 else
4022 }
4024 /* Print an error message about being unable to build a call to FN with
4025 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
4026 be located; CANDIDATES is a possibly empty list of such
4027 functions. */
4029 static void
4032 {
4039 else
4044 }
4046 /* Return an expression for a call to FN (a namespace-scope function,
4047 or a static member function) with the ARGS. This may change
4048 ARGS. */
4050 tree
4052 tsubst_flags_t complain)
4053 {
4057 tree result;
4060 {
4064 }
4069 /* If this function was found without using argument dependent
4070 lookup, then we want to ignore any undeclared friend
4071 functions. */
4073 {
4078 {
4082 }
4083 }
4085 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4089 complain);
4092 {
4094 {
4095 // If there is a single (non-viable) function candidate,
4096 // let the error be diagnosed by cp_build_function_call_vec.
4101 // Otherwise, emit notes for non-viable candidates.
4105 }
4107 }
4108 else
4109 {
4111 /* If fn is template_id_expr, the call has explicit template arguments
4112 (e.g. func<int>(5)), communicate this info to build_over_call
4113 through flags so that later we can use it to decide whether to warn
4114 about peculiar null pointer conversion. */
4116 {
4117 /* If overload resolution selects a specialization of a
4118 function concept for non-dependent template arguments,
4119 the expression is true if the constraints are satisfied
4120 and false otherwise.
4122 NOTE: This is an extension of Concepts Lite TS that
4123 allows constraints to be used in expressions. */
4125 {
4131 }
4134 }
4137 }
4139 /* Free all the conversions we allocated. */
4143 }
4145 /* Build a call to a global operator new. FNNAME is the name of the
4146 operator (either "operator new" or "operator new[]") and ARGS are
4147 the arguments provided. This may change ARGS. *SIZE points to the
4148 total number of bytes required by the allocation, and is updated if
4149 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
4150 be used. If this function determines that no cookie should be
4151 used, after all, *COOKIE_SIZE is set to NULL_TREE. If SIZE_CHECK
4152 is not NULL_TREE, it is evaluated before calculating the final
4153 array size, and if it fails, the array size is replaced with
4154 (size_t)-1 (usually triggering a std::bad_alloc exception). If FN
4155 is non-NULL, it will be set, upon return, to the allocation
4156 function called. */
4158 tree
4162 {
4164 tree fns;
4171 /* Set to (size_t)-1 if the size check fails. */
4173 {
4179 }
4185 /* Based on:
4187 [expr.new]
4189 If this lookup fails to find the name, or if the allocated type
4190 is not a class type, the allocation function's name is looked
4191 up in the global scope.
4193 we disregard block-scope declarations of "operator new". */
4196 /* Figure out what function is being called. */
4198 complain);
4200 /* If no suitable function could be found, issue an error message
4201 and give up. */
4203 {
4207 }
4209 /* If a cookie is required, add some extra space. Whether
4210 or not a cookie is required cannot be determined until
4211 after we know which function was called. */
4213 {
4215 tree arg_types;
4218 /* Skip the size_t parameter. */
4220 /* Check the remaining parameters (if any). */
4224 ptr_type_node))
4226 /* If we need a cookie, adjust the number of bytes allocated. */
4228 {
4229 /* Update the total size. */
4231 /* Set to (size_t)-1 if the size check fails. */
4235 /* Update the argument list to reflect the adjusted size. */
4237 }
4238 else
4240 }
4242 /* Tell our caller which function we decided to call. */
4246 /* Build the CALL_EXPR. */
4248 }
4250 /* Build a new call to operator(). This may change ARGS. */
4252 static tree
4254 {
4268 {
4270 /* It's no good looking for an overloaded operator() on a
4271 pointer-to-member-function. */
4272 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
4274 }
4277 {
4281 }
4282 else
4286 {
4290 }
4292 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4296 {
4304 }
4309 {
4318 {
4325 add_template_conv_candidate
4329 else
4333 }
4334 }
4336 /* Be strict here because if we choose a bad conversion candidate, the
4337 errors we get won't mention the call context. */
4340 {
4342 {
4346 }
4348 }
4349 else
4350 {
4353 {
4355 {
4359 }
4361 }
4362 /* Since cand->fn will be a type, not a function, for a conversion
4363 function, we must be careful not to unconditionally look at
4364 DECL_NAME here. */
4368 else
4369 {
4371 complain);
4374 }
4375 }
4377 /* Free all the conversions we allocated. */
4381 }
4383 /* Wrapper for above. */
4385 tree
4387 {
4388 tree ret;
4393 }
4395 /* Called by op_error to prepare format strings suitable for the error
4396 function. It concatenates a prefix (controlled by MATCH), ERRMSG,
4397 and a suffix (controlled by NTYPES). */
4401 {
4411 else
4415 }
4417 static void
4420 {
4425 else
4429 {
4435 else
4447 else
4457 else
4468 else
4478 else
4483 else
4487 else
4492 }
4493 }
4495 /* Return the implicit conversion sequence that could be used to
4496 convert E1 to E2 in [expr.cond]. */
4500 {
4506 /* [expr.cond]
4508 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
4509 implicitly converted (clause _conv_) to the type "lvalue reference to
4510 T2", subject to the constraint that in the conversion the
4511 reference must bind directly (_dcl.init.ref_) to an lvalue.
4513 If E2 is an xvalue: E1 can be converted to match E2 if E1 can be
4514 implicitly converted to the type "rvalue reference to T2", subject to
4515 the constraint that the reference must bind directly. */
4517 {
4520 t1,
4521 e1,
4523 LOOKUP_NO_TEMP_BIND|LOOKUP_NO_RVAL_BIND
4525 complain);
4528 }
4530 /* If E2 is a prvalue or if neither of the conversions above can be done
4531 and at least one of the operands has (possibly cv-qualified) class
4532 type: */
4536 /* [expr.cond]
4538 If E1 and E2 have class type, and the underlying class types are
4539 the same or one is a base class of the other: E1 can be converted
4540 to match E2 if the class of T2 is the same type as, or a base
4541 class of, the class of T1, and the cv-qualification of T2 is the
4542 same cv-qualification as, or a greater cv-qualification than, the
4543 cv-qualification of T1. If the conversion is applied, E1 is
4544 changed to an rvalue of type T2 that still refers to the original
4545 source class object (or the appropriate subobject thereof). */
4548 {
4550 {
4555 else
4558 }
4559 else
4561 }
4562 else
4563 /* [expr.cond]
4565 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
4566 converted to the type that expression E2 would have if E2 were
4567 converted to an rvalue (or the type it has, if E2 is an rvalue). */
4570 }
4572 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
4573 arguments to the conditional expression. */
4575 static tree
4577 tsubst_flags_t complain)
4578 {
4579 tree arg2_type;
4580 tree arg3_type;
4589 /* As a G++ extension, the second argument to the conditional can be
4590 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4591 c'.) If the second operand is omitted, make sure it is
4592 calculated only once. */
4594 {
4599 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4602 else
4604 }
4606 /* If something has already gone wrong, just pass that fact up the
4607 tree. */
4617 {
4622 /* force_rvalue can return error_mark on valid arguments. */
4634 {
4635 /* Rely on the error messages of the scalar version. */
4644 {
4652 }
4656 /* We could pass complain & tf_warning to unsafe_conversion_p,
4657 but the warnings (like Wsign-conversion) have already been
4658 given by the scalar build_conditional_expr_1. We still check
4659 unsafe_conversion_p to forbid truncating long long -> float. */
4661 {
4666 }
4668 {
4673 }
4683 }
4686 {
4692 {
4696 {
4702 }
4704 {
4710 }
4713 }
4714 }
4720 {
4723 "incompatible vector types in conditional expression: "
4727 }
4733 }
4735 /* [expr.cond]
4737 The first expression is implicitly converted to bool (clause
4738 _conv_). */
4740 LOOKUP_NORMAL);
4744 /* [expr.cond]
4746 If either the second or the third operand has type (possibly
4747 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4748 array-to-pointer (_conv.array_), and function-to-pointer
4749 (_conv.func_) standard conversions are performed on the second
4750 and third operands. */
4754 {
4755 /* Do the conversions. We don't these for `void' type arguments
4756 since it can't have any effect and since decay_conversion
4757 does not handle that case gracefully. */
4765 /* [expr.cond]
4767 One of the following shall hold:
4769 --The second or the third operand (but not both) is a
4770 throw-expression (_except.throw_); the result is of the
4771 type of the other and is an rvalue.
4773 --Both the second and the third operands have type void; the
4774 result is of type void and is an rvalue.
4776 We must avoid calling force_rvalue for expressions of type
4777 "void" because it will complain that their value is being
4778 used. */
4781 {
4783 {
4787 }
4790 }
4793 {
4795 {
4799 }
4802 }
4805 else
4806 {
4808 {
4811 "second operand to the conditional operator "
4812 "is of type %<void%>, but the third operand is "
4814 else
4816 "third operand to the conditional operator "
4817 "is of type %<void%>, but the second operand is "
4819 }
4821 }
4825 }
4826 /* [expr.cond]
4828 Otherwise, if the second and third operand have different types,
4829 and either has (possibly cv-qualified) class type, or if both are
4830 glvalues of the same value category and the same type except for
4831 cv-qualification, an attempt is made to convert each of those operands
4832 to the type of the other. */
4836 arg3_type)
4840 {
4845 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4851 /* [expr.cond]
4853 If both can be converted, or one can be converted but the
4854 conversion is ambiguous, the program is ill-formed. If
4855 neither can be converted, the operands are left unchanged and
4856 further checking is performed as described below. If exactly
4857 one conversion is possible, that conversion is applied to the
4858 chosen operand and the converted operand is used in place of
4859 the original operand for the remainder of this section. */
4864 {
4866 {
4873 else
4875 }
4877 }
4879 {
4883 /* Even if CONV2 is a valid conversion, the result of the
4884 conversion may be invalid. For example, if ARG3 has type
4885 "volatile X", and X does not have a copy constructor
4886 accepting a "volatile X&", then even if ARG2 can be
4887 converted to X, the conversion will fail. */
4891 }
4893 {
4900 }
4902 /* Free all the conversions we allocated. */
4908 /* If, after the conversion, both operands have class type,
4909 treat the cv-qualification of both operands as if it were the
4910 union of the cv-qualification of the operands.
4912 The standard is not clear about what to do in this
4913 circumstance. For example, if the first operand has type
4914 "const X" and the second operand has a user-defined
4915 conversion to "volatile X", what is the type of the second
4916 operand after this step? Making it be "const X" (matching
4917 the first operand) seems wrong, as that discards the
4918 qualification without actually performing a copy. Leaving it
4919 as "volatile X" seems wrong as that will result in the
4920 conditional expression failing altogether, even though,
4921 according to this step, the one operand could be converted to
4922 the type of the other. */
4930 }
4932 /* [expr.cond]
4934 If the second and third operands are glvalues of the same value
4935 category and have the same type, the result is of that type and
4936 value category. */
4940 {
4945 }
4947 /* [expr.cond]
4949 Otherwise, the result is an rvalue. If the second and third
4950 operand do not have the same type, and either has (possibly
4951 cv-qualified) class type, overload resolution is used to
4952 determine the conversions (if any) to be applied to the operands
4953 (_over.match.oper_, _over.built_). */
4957 {
4962 /* Rearrange the arguments so that add_builtin_candidate only has
4963 to know about two args. In build_builtin_candidate, the
4964 arguments are unscrambled. */
4969 COND_EXPR,
4970 NOP_EXPR,
4972 args,
4975 /* [expr.cond]
4977 If the overload resolution fails, the program is
4978 ill-formed. */
4981 {
4986 }
4989 {
4991 {
4994 }
4996 }
4998 /* [expr.cond]
5000 Otherwise, the conversions thus determined are applied, and
5001 the converted operands are used in place of the original
5002 operands for the remainder of this section. */
5011 }
5013 /* [expr.cond]
5015 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
5016 and function-to-pointer (_conv.func_) standard conversions are
5017 performed on the second and third operands.
5019 We need to force the lvalue-to-rvalue conversion here for class types,
5020 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
5021 that isn't wrapped with a TARGET_EXPR plays havoc with exception
5022 regions. */
5035 /* [expr.cond]
5037 After those conversions, one of the following shall hold:
5039 --The second and third operands have the same type; the result is of
5040 that type. */
5043 /* [expr.cond]
5045 --The second and third operands have arithmetic or enumeration
5046 type; the usual arithmetic conversions are performed to bring
5047 them to a common type, and the result is of that type. */
5052 {
5053 /* In this case, there is always a common type. */
5055 arg3_type);
5058 "implicit conversion from %qT to %qT to "
5060 loc);
5064 {
5068 /* Two enumerators from the same enumeration can have different
5074 }
5081 {
5085 }
5089 }
5090 /* [expr.cond]
5092 --The second and third operands have pointer type, or one has
5093 pointer type and the other is a null pointer constant; pointer
5094 conversions (_conv.ptr_) and qualification conversions
5095 (_conv.qual_) are performed to bring them to their composite
5096 pointer type (_expr.rel_). The result is of the composite
5097 pointer type.
5099 --The second and third operands have pointer to member type, or
5100 one has pointer to member type and the other is a null pointer
5101 constant; pointer to member conversions (_conv.mem_) and
5102 qualification conversions (_conv.qual_) are performed to bring
5103 them to a common type, whose cv-qualification shall match the
5104 cv-qualification of either the second or the third operand.
5105 The result is of the common type. */
5113 {
5116 complain);
5121 }
5124 {
5129 }
5134 valid_operands:
5137 /* Avoid folding within decltype (c++/42013) and noexcept. */
5140 /* We can't use result_type below, as fold might have returned a
5141 throw_expr. */
5144 {
5145 /* Expand both sides into the same slot, hopefully the target of
5146 the ?: expression. We used to check for TARGET_EXPRs here,
5147 but now we sometimes wrap them in NOP_EXPRs so the test would
5148 fail. */
5151 /* If this expression is an rvalue, but might be mistaken for an
5152 lvalue, we must add a NON_LVALUE_EXPR. */
5154 }
5155 else
5159 }
5161 /* Wrapper for above. */
5163 tree
5165 tsubst_flags_t complain)
5166 {
5167 tree ret;
5172 }
5174 /* OPERAND is an operand to an expression. Perform necessary steps
5175 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
5176 returned. */
5178 static tree
5180 {
5182 {
5185 /* Make sure the template type is instantiated now. */
5187 }
5190 }
5192 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
5193 OVERLOAD) to the CANDIDATES, returning an updated list of
5194 CANDIDATES. The ARGS are the arguments provided to the call;
5195 if FIRST_ARG is non-null it is the implicit object argument,
5196 otherwise the first element of ARGS is used if needed. The
5197 EXPLICIT_TARGS are explicit template arguments provided.
5198 TEMPLATE_ONLY is true if only template functions should be
5199 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
5200 add_function_candidate. */
5202 static void
5204 tree return_type,
5209 tsubst_flags_t complain)
5210 {
5211 tree ctype;
5215 unification_kind_t strict;
5216 tree fn;
5221 /* Precalculate special handling of constructors and conversion ops. */
5224 {
5228 /* We're doing return_type(x). */
5230 else
5231 /* We're doing x.operator return_type(). */
5233 /* [over.match.funcs] For conversion functions, the function
5234 is considered to be a member of the class of the implicit
5235 object argument for the purpose of defining the type of
5236 the implicit object parameter. */
5238 }
5239 else
5240 {
5242 {
5244 /* For list-initialization we consider explicit constructors
5245 and complain if one is chosen. */
5246 check_converting
5249 }
5250 else
5251 {
5254 }
5257 }
5261 else
5262 /* Delay creating the implicit this parameter until it is needed. */
5266 {
5267 tree fn_first_arg;
5277 /* Figure out which set of arguments to use. */
5279 {
5280 /* If this function is a non-static member and we didn't get an
5281 implicit object argument, move it out of args. */
5283 {
5285 tree arg;
5292 }
5296 }
5297 else
5298 {
5299 /* Otherwise, just use the list of arguments provided. */
5302 }
5306 fn,
5307 ctype,
5308 explicit_targs,
5309 fn_first_arg,
5310 fn_args,
5311 return_type,
5312 access_path,
5313 conversion_path,
5314 flags,
5315 strict,
5316 complain);
5319 fn,
5320 ctype,
5321 fn_first_arg,
5322 fn_args,
5323 access_path,
5324 conversion_path,
5325 flags,
5326 complain);
5327 }
5328 }
5330 static tree
5333 {
5336 tree fnname;
5354 {
5358 }
5359 else
5366 {
5371 /* Use build_op_new_call and build_op_delete_call instead. */
5375 /* Use build_op_call instead. */
5382 /* These are saved for the sake of warn_logical_operator. */
5392 /* These are saved for the sake of maybe_warn_bool_compare. */
5397 /* =, ->, [], () must be non-static member functions. */
5408 }
5414 /* Use build_conditional_expr instead. */
5430 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5433 /* Add namespace-scope operators to the list of functions to
5434 consider. */
5446 /* Add class-member operators to the candidate set. */
5448 {
5449 tree fns;
5453 {
5456 }
5464 }
5465 /* Per 13.3.1.2/3, 2nd bullet, if no operand has a class type, then
5466 only non-member functions that have type T1 or reference to
5467 cv-qualified-opt T1 for the first argument, if the first argument
5468 has an enumeration type, or T2 or reference to cv-qualified-opt
5469 T2 for the second argument, if the second argument has an
5470 enumeration type. Filter out those that don't match. */
5472 {
5476 {
5486 {
5492 && (same_type_ignoring_top_level_qualifiers_p
5497 }
5499 /* No argument has an appropriate type, so remove this
5500 candidate function from the list. */
5502 {
5505 }
5506 }
5507 }
5513 {
5516 /* For these, the built-in candidates set is empty
5517 [over.match.oper]/3. We don't want non-strict matches
5518 because exact matches are always possible with built-in
5519 operators. The built-in candidate set for COMPONENT_REF
5520 would be empty too, but since there are no such built-in
5521 operators, we accept non-strict matches for them. */
5528 }
5532 {
5534 {
5537 /* Don't try anything fancy if we're not allowed to produce
5538 errors. */
5542 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
5543 distinguish between prefix and postfix ++ and
5544 operator++() was used for both, so we allow this with
5545 -fpermissive. */
5546 else
5547 {
5553 }
5560 else
5566 /* The caller will deal with these. */
5576 {
5577 /* If one of the arguments of the operator represents
5578 an invalid use of member function pointer, try to report
5579 a meaningful error ... */
5584 else
5585 {
5586 /* ... Otherwise, report the more generic
5587 "no matching operator found" error */
5590 }
5591 }
5594 }
5595 }
5596 else
5597 {
5600 {
5602 {
5605 }
5607 }
5609 {
5615 else
5617 }
5618 else
5619 {
5620 /* Give any warnings we noticed during overload resolution. */
5622 {
5626 }
5628 /* Check for comparison of different enum types. */
5630 {
5642 {
5646 }
5650 }
5652 /* We need to strip any leading REF_BIND so that bitfields
5653 don't cause errors. This should not remove any important
5654 conversions, because builtins don't apply to class
5655 objects directly. */
5662 {
5666 else
5669 /* We need to call warn_logical_operator before
5670 converting arg2 to a boolean_type, but after
5671 decaying an enumerator to its value. */
5678 }
5680 {
5685 }
5687 }
5688 }
5690 user_defined_result_ready:
5692 /* Free all the conversions we allocated. */
5698 builtin:
5700 {
5714 /* Fall through. */
5727 /* Fall through. */
5760 complain),
5763 /* The caller will deal with these. */
5771 }
5773 }
5775 /* Wrapper for above. */
5777 tree
5781 {
5782 tree ret;
5788 }
5790 /* Returns true if FN has two parameters, of which the second has type
5791 size_t. */
5793 static bool
5795 {
5800 }
5802 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
5803 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
5805 bool
5807 {
5808 /* A template instance is never a usual deallocation function,
5809 regardless of its signature. */
5814 /* If a class T has a member deallocation function named operator delete
5815 with exactly one parameter, then that function is a usual
5816 (non-placement) deallocation function. If class T does not declare
5817 such an operator delete but does declare a member deallocation
5818 function named operator delete with exactly two parameters, the second
5819 of which has type std::size_t (18.2), then this function is a usual
5820 deallocation function. */
5827 }
5829 /* Build a call to operator delete. This has to be handled very specially,
5830 because the restrictions on what signatures match are different from all
5831 other call instances. For a normal delete, only a delete taking (void *)
5832 or (void *, size_t) is accepted. For a placement delete, only an exact
5833 match with the placement new is accepted.
5835 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
5836 ADDR is the pointer to be deleted.
5837 SIZE is the size of the memory block to be deleted.
5838 GLOBAL_P is true if the delete-expression should not consider
5839 class-specific delete operators.
5840 PLACEMENT is the corresponding placement new call, or NULL_TREE.
5842 If this call to "operator delete" is being generated as part to
5843 deallocate memory allocated via a new-expression (as per [expr.new]
5844 which requires that if the initialization throws an exception then
5845 we call a deallocation function), then ALLOC_FN is the allocation
5846 function. */
5848 tree
5852 {
5866 /* In [class.free]
5868 If the result of the lookup is ambiguous or inaccessible, or if
5869 the lookup selects a placement deallocation function, the
5870 program is ill-formed.
5872 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5873 {
5877 }
5878 else
5884 /* Strip const and volatile from addr. */
5888 {
5889 /* "A declaration of a placement deallocation function matches the
5890 declaration of a placement allocation function if it has the same
5891 number of parameters and, after parameter transformations (8.3.5),
5892 all parameter types except the first are identical."
5894 So we build up the function type we want and ask instantiate_type
5895 to get it for us. */
5907 /* "If the lookup finds the two-parameter form of a usual deallocation
5908 function (3.7.4.2) and that function, considered as a placement
5909 deallocation function, would have been selected as a match for the
5910 allocation function, the program is ill-formed." */
5912 {
5920 /* But if the class has an operator delete (void *), then that is
5921 the usual deallocation function, so we shouldn't complain
5922 about using the operator delete (void *, size_t). */
5926 {
5931 }
5932 /* Before C++14 a two-parameter global deallocation function is
5933 always a placement deallocation function, but warn if
5934 -Wc++14-compat. */
5936 {
5941 }
5944 {
5946 {
5947 /* Only mention C++14 for namespace-scope delete. */
5950 else
5952 "%qD is a usual (non-placement) deallocation "
5954 }
5955 }
5956 else
5958 ok:;
5959 }
5960 }
5961 else
5962 /* "Any non-placement deallocation function matches a non-placement
5963 allocation function. If the lookup finds a single matching
5964 deallocation function, that function will be called; otherwise, no
5965 deallocation function will be called." */
5968 {
5971 {
5973 /* "If a class T has a member deallocation function named
5974 operator delete with exactly one parameter, then that
5975 function is a usual (non-placement) deallocation
5976 function. If class T does not declare such an operator
5977 delete but does declare a member deallocation function named
5978 operator delete with exactly two parameters, the second of
5979 which has type std::size_t (18.2), then this function is a
5980 usual deallocation function."
5982 So in a class (void*) beats (void*, size_t). */
5984 {
5987 }
5988 /* At global scope (in C++14 and above) the rules are different:
5990 If deallocation function lookup finds both a usual
5991 deallocation function with only a pointer parameter and a
5992 usual deallocation function with both a pointer parameter
5993 and a size parameter, the function to be called is selected
5994 as follows:
5996 * If the type is complete and if, for the second alternative
5997 (delete array) only, the operand is a pointer to a class
5998 type with a non-trivial destructor or a (possibly
5999 multi-dimensional) array thereof, the function with two
6000 parameters is selected.
6002 * Otherwise, it is unspecified which of the two deallocation
6003 functions is selected. */
6004 else
6005 {
6009 /* We need a cookie to determine the array size. */
6014 }
6015 }
6016 }
6018 /* If we have a matching function, call it. */
6020 {
6023 /* If the FN is a member function, make sure that it is
6024 accessible. */
6027 complain);
6029 /* Core issue 901: It's ok to new a type with deleted delete. */
6034 {
6035 /* The placement args might not be suitable for overload
6036 resolution at this point, so build the call directly. */
6046 }
6047 else
6048 {
6049 tree ret;
6057 }
6058 }
6060 /* [expr.new]
6062 If no unambiguous matching deallocation function can be found,
6063 propagating the exception does not cause the object's memory to
6064 be freed. */
6066 {
6070 alloc_fn);
6072 }
6078 }
6080 /* If the current scope isn't allowed to access DECL along
6081 BASETYPE_PATH, give an error. The most derived class in
6082 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
6083 the declaration to use in the error diagnostic. */
6085 bool
6087 tsubst_flags_t complain)
6088 {
6092 {
6094 {
6096 {
6100 }
6102 {
6106 }
6107 else
6108 {
6111 }
6112 }
6114 }
6117 }
6119 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
6120 bitwise or of LOOKUP_* values. If any errors are warnings are
6121 generated, set *DIAGNOSTIC_FN to "error" or "warning",
6122 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
6123 to NULL. */
6125 static tree
6128 {
6141 else
6144 }
6146 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
6147 EXPR is implicitly converted to type TOTYPE.
6148 FN and ARGNUM are used for diagnostics. */
6150 static void
6152 {
6153 /* Issue warnings about peculiar, but valid, uses of NULL. */
6156 {
6157 source_location loc =
6164 else
6167 }
6169 /* Issue warnings if "false" is converted to a NULL pointer */
6172 {
6175 "converting %<false%> to pointer type for argument %P "
6177 else
6180 }
6181 }
6183 /* We gave a diagnostic during a conversion. If this was in the second
6184 standard conversion sequence of a user-defined conversion sequence, say
6185 which user-defined conversion. */
6187 static void
6189 {
6193 {
6197 }
6198 }
6200 /* Perform the conversions in CONVS on the expression EXPR. FN and
6201 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
6202 indicates the `this' argument of a method. INNER is nonzero when
6203 being called to continue a conversion chain. It is negative when a
6204 reference binding will be applied, positive otherwise. If
6205 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
6206 conversions will be emitted if appropriate. If C_CAST_P is true,
6207 this conversion is coming from a C-style cast; in that case,
6208 conversions to inaccessible bases are permitted. */
6210 static tree
6214 {
6216 diagnostic_t diag_kind;
6232 {
6236 /* Give a helpful error if this is bad because of excess braces. */
6241 {
6247 }
6249 /* Give a helpful error if this is bad because a conversion to bool
6250 from std::nullptr_t requires direct-initialization. */
6258 {
6260 {
6263 totype);
6269 complain);
6273 complain);
6274 else
6280 }
6282 {
6286 complain);
6288 }
6293 complain);
6296 }
6305 }
6311 {
6313 {
6318 /* If we're initializing from {}, it's value-initialization. Note
6319 that under the resolution of core 1630, value-initialization can
6320 use explicit constructors. */
6324 {
6329 {
6332 }
6334 }
6336 /* When converting from an init list we consider explicit
6337 constructors, but actually trying to call one is an error. */
6339 /* Unless this is for direct-list-initialization. */
6341 {
6346 }
6350 /* Set user_conv_p on the argument conversions, so rvalue/base
6351 handling knows not to allow any more UDCs. */
6357 /* If this is a constructor or a function returning an aggr type,
6358 we need to build up a TARGET_EXPR. */
6360 {
6363 /* Remember that this was list-initialization. */
6366 }
6369 }
6372 {
6378 else
6380 }
6385 /* Convert a constant to its underlying value, unless we are
6386 about to bind it to a reference, in which case we need to
6387 leave it as an lvalue. */
6389 {
6392 /* If __null has been converted to an integer type, we do not
6393 want to warn about uses of EXPR as an integer, rather than
6394 as a pointer. */
6396 }
6399 /* We leave bad_p off ck_ambig because overload resolution considers
6400 it valid, it just fails when we try to perform it. So we need to
6401 check complain here, too. */
6403 {
6404 /* Call build_user_type_conversion again for the error. */
6406 complain);
6410 }
6414 {
6415 /* Conversion to std::initializer_list<T>. */
6423 /* Convert all the elements. */
6425 {
6436 }
6437 /* Build up the array. */
6438 elttype = cp_build_qualified_type
6442 /* Take the address explicitly rather than via decay_conversion
6443 to avoid the error about taking the address of a temporary. */
6449 /* Build up the initializer_list object. */
6457 }
6461 {
6470 }
6473 complain);
6480 };
6485 c_cast_p,
6486 complain);
6491 {
6499 /* Else fall through. */
6502 {
6503 /* We are going to bind a reference directly to a base-class
6504 subobject of EXPR. */
6505 /* Build an expression for `*((base*) &expr)'. */
6509 }
6511 /* Copy-initialization where the cv-unqualified version of the source
6512 type is the same class as, or a derived class of, the class of the
6513 destination [is treated as direct-initialization]. [dcl.init] */
6516 /* This conversion is being done in the context of a user-defined
6517 conversion (i.e. the second step of copy-initialization), so
6518 don't allow any more. */
6520 else
6526 /* Copy-list-initialization doesn't actually involve a copy. */
6530 {
6535 }
6540 {
6544 {
6557 else
6564 }
6566 /* If necessary, create a temporary.
6568 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
6569 that need temporaries, even when their types are reference
6570 compatible with the type of reference being bound, so the
6571 upcoming call to cp_build_addr_expr doesn't fail. */
6575 {
6576 /* Otherwise, a temporary of type "cv1 T1" is created and
6577 initialized from the initializer expression using the rules
6578 for a non-reference copy-initialization (8.5). */
6587 {
6588 /* If the reference is volatile or non-const, we
6589 cannot create a temporary. */
6596 else
6600 }
6601 /* If the source is a packed field, and we must use a copy
6602 constructor, then building the target expr will require
6603 binding the field to the reference parameter to the
6604 copy constructor, and we'll end up with an infinite
6605 loop. If we can use a bitwise copy, then we'll be
6606 OK. */
6610 {
6614 }
6616 {
6619 }
6621 }
6623 /* Take the address of the thing to which we will bind the
6624 reference. */
6629 /* Convert it to a pointer to the type referred to by the
6630 reference. This will adjust the pointer if a derived to
6631 base conversion is being performed. */
6634 /* Convert the pointer to the desired reference type. */
6636 }
6642 /* Warn about deprecated conversion if appropriate. */
6658 }
6666 else
6670 }
6672 /* ARG is being passed to a varargs function. Perform any conversions
6673 required. Return the converted value. */
6675 tree
6677 {
6678 tree arg_type;
6681 /* [expr.call]
6683 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
6684 standard conversions are performed. */
6687 /* [expr.call]
6689 If the argument has integral or enumeration type that is subject
6690 to the integral promotions (_conv.prom_), or a floating point
6691 type that is subject to the floating point promotion
6692 (_conv.fpprom_), the value of the argument is converted to the
6693 promoted type before the call. */
6698 {
6702 "implicit conversion from %qT to %qT when passing "
6706 }
6710 {
6712 {
6714 complain);
6724 }
6725 else
6727 }
6733 /* In a template (or ill-formed code), we can have an incomplete type
6734 even after require_complete_type_sfinae, in which case we don't know
6735 whether it has trivial copy or not. */
6737 {
6738 /* Build up a real lvalue-to-rvalue conversion in case the
6739 copy constructor is trivial but not callable. */
6743 /* [expr.call] 5.2.2/7:
6744 Passing a potentially-evaluated argument of class type (Clause 9)
6745 with a non-trivial copy constructor or a non-trivial destructor
6746 with no corresponding parameter is conditionally-supported, with
6747 implementation-defined semantics.
6749 We support it as pass-by-invisible-reference, just like a normal
6750 value parameter.
6752 If the call appears in the context of a sizeof expression,
6753 it is not potentially-evaluated. */
6757 {
6760 "passing objects of non-trivially-copyable "
6762 arg_type);
6764 }
6765 }
6768 }
6770 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
6772 tree
6774 {
6776 {
6780 }
6790 {
6793 }
6797 {
6798 /* conditionally-supported behavior [expr.call] 5.2.2/7. Let's treat
6799 it as pass by invisible reference. */
6801 "receiving objects of non-trivially-copyable type %q#T "
6807 }
6810 }
6812 /* TYPE has been given to va_arg. Apply the default conversions which
6813 would have happened when passed via ellipsis. Return the promoted
6814 type, or the passed type if there is no change. */
6816 tree
6818 {
6819 tree promote;
6821 /* Perform the array-to-pointer and function-to-pointer
6822 conversions. */
6830 }
6832 /* ARG is a default argument expression being passed to a parameter of
6833 the indicated TYPE, which is a parameter to FN. PARMNUM is the
6834 zero-based argument number. Do any required conversions. Return
6835 the converted value. */
6838 void
6842 void
6846 tree
6848 tsubst_flags_t complain)
6849 {
6851 tree t;
6853 /* See through clones. */
6856 /* Detect recursion. */
6859 {
6863 }
6865 /* If the ARG is an unparsed default argument expression, the
6866 conversion cannot be performed. */
6868 {
6873 }
6880 /* Due to:
6882 [dcl.fct.default]
6884 The names in the expression are bound, and the semantic
6885 constraints are checked, at the point where the default
6886 expressions appears.
6888 we must not perform access checks here. */
6890 /* We must make a copy of ARG, in case subsequent processing
6891 alters any part of it. */
6895 complain);
6902 }
6904 /* Returns the type which will really be used for passing an argument of
6905 type TYPE. */
6907 tree
6909 {
6910 /* Pass classes with copy ctors by invisible reference. */
6912 {
6914 /* There are no other pointers to this temporary. */
6916 }
6924 }
6926 /* Actually perform the appropriate conversion. */
6928 tree
6930 {
6931 tree bitfield_type;
6933 /* If VAL is a bitfield, then -- since it has already been converted
6934 to TYPE -- it cannot have a precision greater than TYPE.
6936 If it has a smaller precision, we must widen it here. For
6937 example, passing "int f:3;" to a function expecting an "int" will
6938 not result in any conversion before this point.
6940 If the precision is the same we must not risk widening. For
6941 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
6942 often have type "int", even though the C++ type for the field is
6943 "long long". If the value is being passed to a function
6944 expecting an "int", then no conversions will be required. But,
6945 if we call convert_bitfield_to_declared_type, the bitfield will
6946 be converted to "long long". */
6953 ;
6954 /* Pass classes with copy ctors by invisible reference. */
6964 {
6973 }
6975 }
6977 /* Returns true iff FN is a function with magic varargs, i.e. ones for
6978 which no conversions at all should be done. This is true for some
6979 builtins which don't act like normal functions. */
6981 bool
6983 {
6989 {
6999 }
7002 }
7004 /* Returns the decl of the dispatcher function if FN is a function version. */
7006 tree
7008 {
7018 {
7022 }
7027 }
7029 /* fn is a function version dispatcher that is marked used. Mark all the
7030 semantically identical function versions it will dispatch as used. */
7032 void
7034 {
7051 /* All semantically identical versions are chained. Traverse and mark each
7052 one of them as used. */
7055 {
7058 }
7059 }
7061 /* Build a call to "the copy constructor" for the type of A, even if it
7062 wouldn't be selected by normal overload resolution. Used for
7063 diagnostics. */
7065 static tree
7067 {
7078 }
7080 /* Subroutine of the various build_*_call functions. Overload resolution
7081 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
7082 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
7083 bitmask of various LOOKUP_* flags which apply to the call itself. */
7085 static tree
7087 {
7095 tree val;
7104 /* In a template, there is no need to perform all of the work that
7105 is normally done. We are only interested in the type of the call
7106 expression, i.e., the return type of the function. Any semantic
7107 errors will be deferred until the template is instantiated. */
7109 {
7111 tree return_type;
7119 else
7120 {
7123 tree arg;
7131 }
7141 }
7143 /* Give any warnings we noticed during overload resolution. */
7145 {
7149 }
7151 /* Make =delete work with SFINAE. */
7156 {
7157 tree access_fn;
7158 /* If FN is a template function, two cases must be considered.
7159 For example:
7161 struct A {
7162 protected:
7163 template <class T> void f();
7164 };
7165 template <class T> struct B {
7166 protected:
7167 void g();
7168 };
7169 struct C : A, B<int> {
7170 using A::f; // #1
7171 using B<int>::g; // #2
7172 };
7174 In case #1 where `A::f' is a member template, DECL_ACCESS is
7175 recorded in the primary template but not in its specialization.
7176 We check access of FN using its primary template.
7178 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
7179 because it is a member of class template B, DECL_ACCESS is
7180 recorded in the specialization `B<int>::g'. We cannot use its
7181 primary template because `B<T>::g' and `B<int>::g' may have
7182 different access. */
7186 else
7191 }
7193 /* If we're checking for implicit delete, don't bother with argument
7194 conversions. */
7196 {
7198 {
7202 }
7206 /* Reject bad conversions now. */
7208 /* else continue to get conversion error. */
7209 }
7211 /* N3276 magic doesn't apply to nested calls. */
7215 /* Find maximum size of vector to hold converted arguments. */
7222 /* The implicit parameters to a constructor are not considered by overload
7223 resolution, and must be of the proper type. */
7225 {
7226 tree object_arg;
7228 {
7231 }
7232 else
7233 {
7236 }
7239 /* We should never try to call the abstract constructor. */
7243 {
7247 }
7248 }
7249 /* Bypass access control for 'this' parameter. */
7251 {
7254 ? first_arg
7257 tree converted_arg;
7258 tree base_binfo;
7261 {
7263 {
7268 }
7269 else
7271 }
7273 /* See if the function member or the whole class type is declared
7274 final and the call can be devirtualized. */
7279 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
7280 X is called for an object that is not of type X, or of a type
7281 derived from X, the behavior is undefined.
7283 So we can assume that anything passed as 'this' is non-null, and
7284 optimize accordingly. */
7286 /* Convert to the base in which the function was declared. */
7289 arg,
7292 /* Check that the base class is accessible. */
7295 {
7300 else
7302 }
7303 /* If fn was found by a using declaration, the conversion path
7304 will be to the derived class, not the base declaring fn. We
7305 must convert from derived to base. */
7316 else
7320 }
7325 {
7332 /* If the argument is NULL and used to (implicitly) instantiate a
7333 template function (and bind one of the template arguments to
7334 the type of 'long int'), we don't want to warn about passing NULL
7335 to non-pointer argument.
7336 For example, if we have this template function:
7338 template<typename T> void func(T x) {}
7340 we want to warn (when -Wconversion is enabled) in this case:
7342 void foo() {
7343 func<int>(NULL);
7344 }
7346 but not in this case:
7348 void foo() {
7349 func(NULL);
7350 }
7351 */
7358 /* Warn about initializer_list deduction that isn't currently in the
7359 working draft. */
7361 && flag_deduce_init_list
7365 {
7378 {
7386 }
7387 }
7389 conversion_warning
7390 ? complain
7397 else
7399 }
7401 /* Default arguments */
7403 {
7409 complain);
7410 }
7412 /* Ellipsis */
7414 {
7417 /* Do no conversions for magic varargs. */
7422 {
7423 /* Avoid infinite recursion trying to call A(...). */
7425 /* Try to call the actual copy constructor for a good error. */
7428 }
7429 else
7432 }
7439 /* Avoid actually calling copy constructors and copy assignment operators,
7440 if possible. */
7447 /* It's unsafe to elide the constructor when handling
7448 a noexcept-expression, it may evaluate to the wrong
7449 value (c++/53025). */
7451 {
7452 tree targ;
7454 tree fa;
7457 /* Pull out the real argument, disregarding const-correctness. */
7463 {
7468 }
7469 else
7474 else
7477 /* [class.copy]: the copy constructor is implicitly defined even if
7478 the implementation elided its use. */
7480 {
7484 }
7486 /* If we're creating a temp and we already have one, don't create a
7487 new one. If we're not creating a temp but we get one, use
7488 INIT_EXPR to collapse the temp into our target. Otherwise, if the
7489 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
7490 temp or an INIT_EXPR otherwise. */
7493 {
7498 }
7500 {
7502 complain));
7506 }
7507 }
7511 {
7512 tree to = stabilize_reference
7519 {
7520 /* Avoid copying empty classes. */
7525 }
7527 {
7530 }
7531 else
7532 {
7533 /* We must only copy the non-tail padding parts. */
7541 build_index_type
7550 }
7553 }
7558 /* FIXME handle trivial default constructor, too. */
7560 /* For calls to a multi-versioned function, overload resolution
7561 returns the function with the highest target priority, that is,
7562 the version that will checked for dispatching first. If this
7563 version is inlinable, a direct call to this version can be made
7564 otherwise the call should go through the dispatcher. */
7569 {
7575 }
7582 /* Don't mess with virtual lookup in instantiate_non_dependent_expr;
7583 virtual functions can't be constexpr. */
7585 {
7586 tree t;
7593 complain);
7599 else
7602 }
7603 else
7604 {
7608 }
7615 }
7617 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
7618 This function performs no overload resolution, conversion, or other
7619 high-level operations. */
7621 tree
7623 tsubst_flags_t complain)
7624 {
7625 tree fndecl;
7628 /* Remember roughly where this call is. */
7635 /* Check that arguments to builtin functions match the expectations. */
7642 /* If it is a built-in array notation function, then the return type of
7643 the function is the element type of the array passed in as array
7644 notation (i.e. the first parameter of the function). */
7646 {
7655 {
7657 {
7660 }
7661 /* for bif == BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_ZERO or
7662 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_ZERO or
7663 BUILT_IN_CILKPLUS_SEC_REDUCE_ANY_NONZERO or
7664 BUILT_IN_CILKPLUS_SEC_REDUCE_ALL_NONZERO or
7665 BUILT_IN_CILKPLUS_SEC_REDUCE_MIN_IND or
7666 BUILT_IN_CILKPLUS_SEC_REDUCE_MAX_IND
7667 The pre-defined return-type is the correct one. */
7671 }
7672 }
7674 /* Some built-in function calls will be evaluated at compile-time in
7675 fold (). Set optimize to 1 when folding __builtin_constant_p inside
7676 a constexpr function so that fold_builtin_1 doesn't fold it to 0. */
7679 && current_function_decl
7688 /* 5.2.2/11: If a function call is a prvalue of object type: if the
7689 function call is either the operand of a decltype-specifier or the
7690 right operand of a comma operator that is the operand of a
7691 decltype-specifier, a temporary object is not introduced for the
7692 prvalue. The type of the prvalue may be incomplete. */
7694 {
7701 }
7703 }
7707 /* Make an expression which yields the address of the Java interface
7708 method FN. This is achieved by generating a call to libjava's
7709 _Jv_LookupInterfaceMethodIdx(). */
7711 static tree
7713 {
7719 {
7723 java_iface_lookup_fn
7726 }
7728 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
7729 This is the first entry in the vtable. */
7731 tf_warning_or_error),
7732 integer_zero_node);
7734 /* Get the java.lang.Class pointer for the interface being called. */
7739 {
7741 iface);
7743 }
7747 /* Determine the itable index of FN. */
7750 {
7755 i++;
7756 }
7761 java_iface_lookup_fn);
7764 }
7766 /* Returns the value to use for the in-charge parameter when making a
7767 call to a function with the indicated NAME.
7769 FIXME:Can't we find a neater way to do this mapping? */
7771 tree
7773 {
7784 /* This function should only be called with one of the names listed
7785 above. */
7788 }
7790 /* Build a call to a constructor, destructor, or an assignment
7791 operator for INSTANCE, an expression with class type. NAME
7792 indicates the special member function to call; *ARGS are the
7793 arguments. ARGS may be NULL. This may change ARGS. BINFO
7794 indicates the base of INSTANCE that is to be passed as the `this'
7795 parameter to the member function called.
7797 FLAGS are the LOOKUP_* flags to use when processing the call.
7799 If NAME indicates a complete object constructor, INSTANCE may be
7800 NULL_TREE. In this case, the caller will call build_cplus_new to
7801 store the newly constructed object into a VAR_DECL. */
7803 tree
7806 {
7807 tree fns;
7808 /* The type of the subobject to be constructed or destroyed. */
7809 tree class_type;
7811 tree ret;
7820 {
7821 /* Resolve the name. */
7826 }
7832 /* Handle the special case where INSTANCE is NULL_TREE. */
7835 else
7836 {
7842 /* Convert to the base class, if necessary. */
7845 {
7847 /* For constructors and destructors, either the base is
7848 non-virtual, or it is virtual but we are doing the
7849 conversion from a constructor or destructor for the
7850 complete object. In either case, we can convert
7851 statically. */
7853 else
7854 /* However, for assignment operators, we must convert
7855 dynamically if the base is virtual. */
7858 }
7859 }
7865 /* When making a call to a constructor or destructor for a subobject
7866 that uses virtual base classes, pass down a pointer to a VTT for
7867 the subobject. */
7871 {
7872 tree vtt;
7873 tree sub_vtt;
7875 /* If the current function is a complete object constructor
7876 or destructor, then we fetch the VTT directly.
7877 Otherwise, we look it up using the VTT we were given. */
7885 current_vtt_parm,
7886 vtt);
7889 else
7893 {
7896 }
7899 }
7904 complain);
7918 }
7920 /* Return the NAME, as a C string. The NAME indicates a function that
7921 is a member of TYPE. *FREE_P is set to true if the caller must
7922 free the memory returned.
7924 Rather than go through all of this, we should simply set the names
7925 of constructors and destructors appropriately, and dispense with
7926 ctor_identifier, dtor_identifier, etc. */
7930 {
7933 /* Assume that we will not allocate memory. */
7935 /* Constructors and destructors are special. */
7937 {
7938 pretty_name
7940 /* For a destructor, add the '~'. */
7944 {
7946 /* Remember that we need to free the memory allocated. */
7948 }
7949 }
7951 {
7954 TFF_PLAIN_IDENTIFIER),
7955 NULL);
7956 /* Remember that we need to free the memory allocated. */
7958 }
7959 else
7963 }
7965 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
7966 be set, upon return, to the function called. ARGS may be NULL.
7967 This may change ARGS. */
7969 static tree
7973 {
7978 tree optype;
7980 tree name;
7983 tree call;
7984 tree fn;
7987 tree orig_instance;
7988 tree orig_fns;
7994 /* We don't know what function we're going to call, yet. */
8003 {
8007 }
8012 /* Dismantle the baselink to collect all the information we need. */
8020 {
8024 }
8035 {
8040 }
8043 /* Under DR 147 A::A() is an invalid constructor call,
8044 not a functional cast. */
8046 {
8056 complain);
8058 }
8060 /* Figure out whether to skip the first argument for the error
8061 message we will display to users if an error occurs. We don't
8062 want to display any compiler-generated arguments. The "this"
8063 pointer hasn't been added yet. However, we must remove the VTT
8064 pointer if this is a call to a base-class constructor or
8065 destructor. */
8068 {
8069 /* Callers should explicitly indicate whether they want to construct
8070 the complete object or just the part without virtual bases. */
8072 /* Similarly for destructors. */
8074 /* Remove the VTT pointer, if present. */
8078 }
8080 /* Process the argument list. */
8082 {
8086 }
8088 /* Consider the object argument to be used even if we end up selecting a
8089 static member function. */
8092 /* It's OK to call destructors and constructors on cv-qualified objects.
8093 Therefore, convert the INSTANCE to the unqualified type, if
8094 necessary. */
8097 {
8099 {
8103 }
8104 }
8108 /* For the overload resolution we need to find the actual `this`
8109 that would be captured if the call turns out to be to a
8110 non-static member function. Do not actually capture it at this
8111 point. */
8113 /* Constructors don't use the enclosing 'this'. */
8115 else
8118 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8121 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
8122 initializer, not T({ }). */
8125 {
8132 /* If the initializer list has no elements and T is a class type with
8133 a default constructor, the object is value-initialized. Handle
8134 this here so we don't need to handle it wherever we use
8135 build_special_member_call. */
8138 /* For a user-provided default constructor, use the normal
8139 mechanisms so that protected access works. */
8144 /* If BASETYPE is an aggregate, we need to do aggregate
8145 initialization. */
8147 {
8150 }
8153 {
8159 }
8161 /* Otherwise go ahead with overload resolution. */
8166 }
8167 else
8168 {
8172 }
8177 {
8179 {
8186 else
8187 {
8190 tree arglist;
8201 }
8203 }
8205 }
8206 else
8207 {
8210 {
8213 tree arglist;
8216 {
8224 else
8230 }
8232 }
8233 else
8234 {
8242 {
8243 /* This is not an error, it is runtime undefined
8244 behavior. */
8253 fn);
8254 }
8259 {
8264 {
8265 /* We captured 'this' in the current lambda now that
8266 we know we really need it. */
8268 }
8269 else
8270 {
8273 fn);
8275 }
8276 }
8279 {
8280 /* Optimize away vtable lookup if we know that this
8281 function can't be overridden. We need to check if
8282 the context and the type where we found fn are the same,
8283 actually FN might be defined in a different class
8284 type because of a using-declaration. In this case, we
8285 do not want to perform a non-virtual call. */
8287 && same_type_ignoring_top_level_qualifiers_p
8293 /* Now we know what function is being called. */
8296 /* Build the actual CALL_EXPR. */
8298 /* In an expression of the form `a->f()' where `f' turns
8299 out to be a static member function, `a' is
8300 none-the-less evaluated. */
8309 /* An explicit call of the form "x->~X()" has type
8310 "void". However, on platforms where destructors
8311 return "this" (i.e., those where
8312 targetm.cxx.cdtor_returns_this is true), such calls
8313 will appear to have a return value of pointer type
8314 to the low-level call machinery. We do not want to
8315 change the low-level machinery, since we want to be
8316 able to optimize "delete f()" on such platforms as
8317 "operator delete(~X(f()))" (rather than generating
8318 "t = f(), ~X(t), operator delete (t)"). */
8320 }
8321 }
8322 }
8325 {
8331 {
8334 }
8337 call = (build_min_non_dep_call_vec
8341 orig_args));
8346 }
8348 /* Free all the conversions we allocated. */
8355 }
8357 /* Wrapper for above. */
8359 tree
8363 {
8364 tree ret;
8370 }
8372 /* Returns true iff standard conversion sequence ICS1 is a proper
8373 subsequence of ICS2. */
8375 static bool
8377 {
8378 /* We can assume that a conversion of the same code
8379 between the same types indicates a subsequence since we only get
8380 here if the types we are converting from are the same. */
8387 {
8397 /* At this point, ICS1 cannot be a proper subsequence of
8398 ICS2. We can get a USER_CONV when we are comparing the
8399 second standard conversion sequence of two user conversion
8400 sequences. */
8410 }
8411 }
8413 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
8414 be any _TYPE nodes. */
8416 bool
8418 {
8422 /* We only allow proper derivation here. The DERIVED_FROM_P macro
8423 considers every class derived from itself. */
8426 }
8428 /* We build the ICS for an implicit object parameter as a pointer
8429 conversion sequence. However, such a sequence should be compared
8430 as if it were a reference conversion sequence. If ICS is the
8431 implicit conversion sequence for an implicit object parameter,
8432 modify it accordingly. */
8434 static void
8436 {
8438 {
8439 /* [over.match.funcs]
8441 For non-static member functions, the type of the
8442 implicit object parameter is "reference to cv X"
8443 where X is the class of which the function is a
8444 member and cv is the cv-qualification on the member
8445 function declaration. */
8447 tree reference_type;
8449 /* The `this' parameter is a pointer to a class type. Make the
8450 implicit conversion talk about a reference to that same class
8451 type. */
8464 }
8465 }
8467 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
8468 and return the initial reference binding conversion. Otherwise,
8469 leave *ICS unchanged and return NULL. */
8473 {
8475 {
8480 }
8483 }
8485 /* Compare two implicit conversion sequences according to the rules set out in
8486 [over.ics.rank]. Return values:
8488 1: ics1 is better than ics2
8489 -1: ics2 is better than ics1
8490 0: ics1 and ics2 are indistinguishable */
8492 static int
8494 {
8495 tree from_type1;
8496 tree from_type2;
8497 tree to_type1;
8498 tree to_type2;
8505 /* REF_BINDING is nonzero if the result of the conversion sequence
8506 is a reference type. In that case REF_CONV is the reference
8507 binding conversion. */
8511 /* Compare badness before stripping the reference conversion. */
8517 /* Handle implicit object parameters. */
8521 /* Handle reference parameters. */
8525 /* List-initialization sequence L1 is a better conversion sequence than
8526 list-initialization sequence L2 if L1 converts to
8527 std::initializer_list<X> for some X and L2 does not. */
8533 /* [over.ics.rank]
8535 When comparing the basic forms of implicit conversion sequences (as
8536 defined in _over.best.ics_)
8538 --a standard conversion sequence (_over.ics.scs_) is a better
8539 conversion sequence than a user-defined conversion sequence
8540 or an ellipsis conversion sequence, and
8542 --a user-defined conversion sequence (_over.ics.user_) is a
8543 better conversion sequence than an ellipsis conversion sequence
8544 (_over.ics.ellipsis_). */
8545 /* Use BAD_CONVERSION_RANK because we already checked for a badness
8546 mismatch. If both ICS are bad, we try to make a decision based on
8547 what would have happened if they'd been good. This is not an
8548 extension, we'll still give an error when we build up the call; this
8549 just helps us give a more helpful error message. */
8559 /* Both conversions are ellipsis conversions. */
8562 /* User-defined conversion sequence U1 is a better conversion sequence
8563 than another user-defined conversion sequence U2 if they contain the
8564 same user-defined conversion operator or constructor and if the sec-
8565 ond standard conversion sequence of U1 is better than the second
8566 standard conversion sequence of U2. */
8568 /* Handle list-conversion with the same code even though it isn't always
8569 ranked as a user-defined conversion and it doesn't have a second
8570 standard conversion sequence; it will still have the desired effect.
8571 Specifically, we need to do the reference binding comparison at the
8572 end of this function. */
8575 {
8591 {
8594 }
8595 else
8596 {
8597 /* For ambiguous or aggregate conversions, use the target type as
8598 a proxy for the conversion function. */
8601 }
8603 /* We can just fall through here, after setting up
8604 FROM_TYPE1 and FROM_TYPE2. */
8607 }
8608 else
8609 {
8613 /* We're dealing with two standard conversion sequences.
8615 [over.ics.rank]
8617 Standard conversion sequence S1 is a better conversion
8618 sequence than standard conversion sequence S2 if
8620 --S1 is a proper subsequence of S2 (comparing the conversion
8621 sequences in the canonical form defined by _over.ics.scs_,
8622 excluding any Lvalue Transformation; the identity
8623 conversion sequence is considered to be a subsequence of
8624 any non-identity conversion sequence */
8635 }
8637 /* One sequence can only be a subsequence of the other if they start with
8638 the same type. They can start with different types when comparing the
8639 second standard conversion sequence in two user-defined conversion
8640 sequences. */
8642 {
8647 }
8649 /* [over.ics.rank]
8651 Or, if not that,
8653 --the rank of S1 is better than the rank of S2 (by the rules
8654 defined below):
8656 Standard conversion sequences are ordered by their ranks: an Exact
8657 Match is a better conversion than a Promotion, which is a better
8658 conversion than a Conversion.
8660 Two conversion sequences with the same rank are indistinguishable
8661 unless one of the following rules applies:
8663 --A conversion that does not a convert a pointer, pointer to member,
8664 or std::nullptr_t to bool is better than one that does.
8666 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
8667 so that we do not have to check it explicitly. */
8676 /* A conversion from scalar arithmetic type to complex is worse than a
8677 conversion between scalar arithmetic types. */
8684 {
8687 else
8689 }
8695 {
8700 }
8701 /* The rules for pointers to members A::* are just like the rules
8702 for pointers A*, except opposite: if B is derived from A then
8703 A::* converts to B::*, not vice versa. For that reason, we
8704 switch the from_ and to_ variables here. */
8711 {
8716 }
8721 {
8722 /* This was one of the pointer or pointer-like conversions.
8724 [over.ics.rank]
8726 --If class B is derived directly or indirectly from class A,
8727 conversion of B* to A* is better than conversion of B* to
8728 void*, and conversion of A* to void* is better than
8729 conversion of B* to void*. */
8732 {
8734 deref_from_type2))
8737 deref_from_type1))
8739 }
8742 {
8744 {
8746 {
8748 deref_to_type1))
8750 }
8751 /* We know that DEREF_TO_TYPE1 is `void' here. */
8753 deref_to_type2))
8755 }
8756 }
8759 {
8760 /* [over.ics.rank]
8762 --If class B is derived directly or indirectly from class A
8763 and class C is derived directly or indirectly from B,
8765 --conversion of C* to B* is better than conversion of C* to
8766 A*,
8768 --conversion of B* to A* is better than conversion of C* to
8769 A* */
8771 {
8773 deref_to_type2))
8776 deref_to_type1))
8778 }
8780 {
8782 deref_from_type1))
8785 deref_from_type2))
8787 }
8788 }
8789 }
8792 {
8795 /* [over.ics.rank]
8797 --binding of an expression of type C to a reference of type
8798 B& is better than binding an expression of type C to a
8799 reference of type A&
8801 --conversion of C to B is better than conversion of C to A, */
8804 {
8809 }
8810 }
8813 {
8816 /* [over.ics.rank]
8818 --binding of an expression of type B to a reference of type
8819 A& is better than binding an expression of type C to a
8820 reference of type A&,
8822 --conversion of B to A is better than conversion of C to A */
8825 {
8830 }
8831 }
8833 /* [over.ics.rank]
8835 --S1 and S2 differ only in their qualification conversion and yield
8836 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
8837 qualification signature of type T1 is a proper subset of the cv-
8838 qualification signature of type T2 */
8842 {
8846 }
8848 /* [over.ics.rank]
8850 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
8851 to an implicit object parameter of a non-static member function
8852 declared without a ref-qualifier, and either S1 binds an lvalue
8853 reference to an lvalue and S2 binds an rvalue reference or S1 binds an
8854 rvalue reference to an rvalue and S2 binds an lvalue reference (C++0x
8855 draft standard, 13.3.3.2)
8857 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
8858 types to which the references refer are the same type except for
8859 top-level cv-qualifiers, and the type to which the reference
8860 initialized by S2 refers is more cv-qualified than the type to
8861 which the reference initialized by S1 refers.
8863 DR 1328 [over.match.best]: the context is an initialization by
8864 conversion function for direct reference binding (13.3.1.6) of a
8865 reference to function type, the return type of F1 is the same kind of
8866 reference (i.e. lvalue or rvalue) as the reference being initialized,
8867 and the return type of F2 is not. */
8870 {
8877 {
8881 /* Don't prefer a bad conversion that drops cv-quals to a bad
8882 conversion with the wrong rvalueness. */
8886 }
8889 {
8893 {
8894 /* Prefer the one that drops fewer cv-quals. */
8899 }
8901 }
8902 }
8904 /* Neither conversion sequence is better than the other. */
8906 }
8908 /* The source type for this standard conversion sequence. */
8910 static tree
8912 {
8914 {
8919 }
8921 }
8923 /* Note a warning about preferring WINNER to LOSER. We do this by storing
8924 a pointer to LOSER and re-running joust to produce the warning if WINNER
8925 is actually used. */
8927 static void
8929 {
8935 }
8937 /* Compare two candidates for overloading as described in
8938 [over.match.best]. Return values:
8940 1: cand1 is better than cand2
8941 -1: cand2 is better than cand1
8942 0: cand1 and cand2 are indistinguishable */
8944 static int
8946 tsubst_flags_t complain)
8947 {
8953 /* Candidates that involve bad conversions are always worse than those
8954 that don't. */
8960 /* If we have two pseudo-candidates for conversions to the same type,
8961 or two candidates for the same function, arbitrarily pick one. */
8966 /* Prefer a non-deleted function over an implicitly deleted move
8967 constructor or assignment operator. This differs slightly from the
8968 wording for issue 1402 (which says the move op is ignored by overload
8969 resolution), but this way produces better error messages. */
8973 {
8980 }
8982 /* a viable function F1
8983 is defined to be a better function than another viable function F2 if
8984 for all arguments i, ICSi(F1) is not a worse conversion sequence than
8985 ICSi(F2), and then */
8987 /* for some argument j, ICSj(F1) is a better conversion sequence than
8988 ICSj(F2) */
8990 /* For comparing static and non-static member functions, we ignore
8991 the implicit object parameter of the non-static function. The
8992 standard says to pretend that the static function has an object
8993 parm, but that won't work with operator overloading. */
8996 {
9002 /* We're comparing a near-match list constructor and a near-match
9003 non-list constructor. Just treat them as unordered. */
9010 else
9011 {
9014 }
9015 }
9018 {
9024 {
9026 && warn_sign_promo
9038 {
9045 else
9050 {
9054 }
9055 else
9057 }
9060 {
9063 }
9065 }
9066 }
9068 /* warn about confusing overload resolution for user-defined conversions,
9069 either between a constructor and a conversion op, or between two
9070 conversion ops. */
9075 {
9081 else
9084 /* We don't want to complain about `X::operator T1 ()'
9085 beating `X::operator T2 () const', when T2 is a no less
9086 cv-qualified version of T1. */
9089 {
9094 {
9097 }
9100 }
9101 else
9107 {
9114 {
9116 }
9117 }
9118 else
9120 }
9125 /* DR 495 moved this tiebreaker above the template ones. */
9126 /* or, if not that,
9127 the context is an initialization by user-defined conversion (see
9128 _dcl.init_ and _over.match.user_) and the standard conversion
9129 sequence from the return type of F1 to the destination type (i.e.,
9130 the type of the entity being initialized) is a better conversion
9131 sequence than the standard conversion sequence from the return type
9132 of F2 to the destination type. */
9135 {
9139 }
9141 /* or, if not that,
9142 F1 is a non-template function and F2 is a template function
9143 specialization. */
9150 /* or, if not that,
9151 F1 and F2 are template functions and the function template for F1 is
9152 more specialized than the template for F2 according to the partial
9153 ordering rules. */
9156 {
9157 winner = more_specialized_fn
9160 /* [temp.func.order]: The presence of unused ellipsis and default
9161 arguments has no effect on the partial ordering of function
9162 templates. add_function_candidate() will not have
9163 counted the "this" argument for constructors. */
9167 }
9169 // C++ Concepts
9170 // or, if not that, F1 is more constrained than F2.
9172 {
9176 }
9178 /* Check whether we can discard a builtin candidate, either because we
9179 have two identical ones or matching builtin and non-builtin candidates.
9181 (Pedantically in the latter case the builtin which matched the user
9182 function should not be added to the overload set, but we spot it here.
9184 [over.match.oper]
9185 ... the builtin candidates include ...
9186 - do not have the same parameter type list as any non-template
9187 non-member candidate. */
9190 {
9196 {
9198 /* Two built-in candidates; arbitrarily pick one. */
9201 /* cand1 is built-in; prefer cand2. */
9203 else
9204 /* cand2 is built-in; prefer cand1. */
9206 }
9207 }
9209 /* For candidates of a multi-versioned function, make the version with
9210 the highest priority win. This version will be checked for dispatching
9211 first. If this version can be inlined into the caller, the front-end
9212 will simply make a direct call to this function. */
9218 {
9224 /* Check if cand1->fn and cand2->fn are versions of the same function. It
9225 is possible that cand1->fn and cand2->fn are function versions but of
9226 different functions. Check types to see if they are versions of the same
9227 function. */
9230 {
9231 /* Always make the version with the higher priority, more
9232 specialized, win. */
9236 else
9238 }
9239 }
9241 /* If the two function declarations represent the same function (this can
9242 happen with declarations in multiple scopes and arg-dependent lookup),
9243 arbitrarily choose one. But first make sure the default args we're
9244 using match. */
9247 {
9254 {
9255 /* Don't crash if the fn is variadic. */
9260 }
9268 {
9271 {
9273 {
9275 {
9277 "default argument mismatch in "
9279 {
9284 }
9285 }
9286 else
9288 }
9289 else
9292 }
9295 }
9298 }
9300 tweak:
9302 /* Extension: If the worst conversion for one candidate is worse than the
9303 worst conversion for the other, take the first. */
9305 {
9310 {
9315 }
9321 {
9322 /* Don't choose a deleted function over ambiguity. */
9326 {
9328 "ISO C++ says that these are ambiguous, even "
9329 "though the worst conversion for the first is better than "
9333 }
9334 else
9337 }
9338 }
9342 }
9344 /* Given a list of candidates for overloading, find the best one, if any.
9345 This algorithm has a worst case of O(2n) (winner is last), and a best
9346 case of O(n/2) (totally ambiguous); much better than a sorting
9347 algorithm. */
9351 {
9356 /* Walk through the list once, comparing each current champ to the next
9357 candidate, knocking out a candidate or two with each comparison. */
9360 {
9364 else
9365 {
9367 {
9372 }
9373 else
9374 {
9377 }
9380 }
9381 }
9383 /* Make sure the champ is better than all the candidates it hasn't yet
9384 been compared to. */
9387 challenger != champ
9390 {
9394 }
9397 }
9399 /* Returns nonzero if things of type FROM can be converted to TO. */
9401 bool
9403 {
9405 /* implicit_conversion only considers user-defined conversions
9406 if it has an expression for the call argument list. */
9410 }
9412 /* Returns nonzero if things of type FROM can be converted to TO with a
9413 standard conversion. */
9415 bool
9417 {
9419 }
9421 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
9423 bool
9425 tsubst_flags_t complain)
9426 {
9431 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9433 /* We want to discard any access checks done for this test,
9434 as we might not be in the appropriate access context and
9435 we'll do the check again when we actually perform the
9436 conversion. */
9443 /* Discard the access checks now. */
9445 /* Free all the conversions we allocated. */
9449 }
9451 /* Like can_convert_arg, but allows dubious conversions as well. */
9453 bool
9455 tsubst_flags_t complain)
9456 {
9460 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9462 /* Try to perform the conversion. */
9465 /* Free all the conversions we allocated. */
9469 }
9471 /* Convert EXPR to TYPE. Return the converted expression.
9473 Note that we allow bad conversions here because by the time we get to
9474 this point we are committed to doing the conversion. If we end up
9475 doing a bad conversion, convert_like will complain. */
9477 tree
9480 {
9488 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9496 {
9498 {
9499 /* If expr has unknown type, then it is an overloaded function.
9500 Call instantiate_type to get good error messages. */
9505 else
9508 }
9510 }
9512 {
9513 /* In a template, we are only concerned about determining the
9514 type of non-dependent expressions, so we do not have to
9515 perform the actual conversion. But for initializers, we
9516 need to be able to perform it at instantiation
9517 (or instantiate_non_dependent_expr) time. */
9521 }
9522 else
9525 /* Free all the conversions we allocated. */
9529 }
9531 tree
9533 {
9535 LOOKUP_IMPLICIT);
9536 }
9538 /* Convert EXPR to TYPE (as a direct-initialization) if that is
9539 permitted. If the conversion is valid, the converted expression is
9540 returned. Otherwise, NULL_TREE is returned, except in the case
9541 that TYPE is a class type; in that case, an error is issued. If
9542 C_CAST_P is true, then this direct-initialization is taking
9543 place as part of a static_cast being attempted as part of a C-style
9544 cast. */
9546 tree
9548 tree expr,
9550 tsubst_flags_t complain)
9551 {
9557 /* [dcl.init]
9559 If the destination type is a (possibly cv-qualified) class type:
9561 -- If the initialization is direct-initialization ...,
9562 constructors are considered. ... If no constructor applies, or
9563 the overload resolution is ambiguous, the initialization is
9564 ill-formed. */
9566 {
9572 }
9574 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9578 c_cast_p,
9582 else
9585 c_cast_p,
9586 complain);
9588 /* Free all the conversions we allocated. */
9592 }
9594 /* When initializing a reference that lasts longer than a full-expression,
9595 this special rule applies:
9597 [class.temporary]
9599 The temporary to which the reference is bound or the temporary
9600 that is the complete object to which the reference is bound
9601 persists for the lifetime of the reference.
9603 The temporaries created during the evaluation of the expression
9604 initializing the reference, except the temporary to which the
9605 reference is bound, are destroyed at the end of the
9606 full-expression in which they are created.
9608 In that case, we store the converted expression into a new
9609 VAR_DECL in a new scope.
9611 However, we want to be careful not to create temporaries when
9612 they are not required. For example, given:
9614 struct B {};
9615 struct D : public B {};
9616 D f();
9617 const B& b = f();
9619 there is no need to copy the return value from "f"; we can just
9620 extend its lifetime. Similarly, given:
9622 struct S {};
9623 struct T { operator S(); };
9624 T t;
9625 const S& s = t;
9627 we can extend the lifetime of the return value of the conversion
9628 operator.
9630 The next several functions are involved in this lifetime extension. */
9632 /* DECL is a VAR_DECL or FIELD_DECL whose type is a REFERENCE_TYPE. The
9633 reference is being bound to a temporary. Create and return a new
9634 VAR_DECL with the indicated TYPE; this variable will store the value to
9635 which the reference is bound. */
9637 tree
9639 {
9640 tree var;
9642 /* Create the variable. */
9645 /* Register the variable. */
9648 {
9649 /* Namespace-scope or local static; give it a mangled name. */
9650 /* FIXME share comdat with decl? */
9651 tree name;
9660 }
9661 else
9662 /* Create a new cleanup level if necessary. */
9666 }
9668 /* EXPR is the initializer for a variable DECL of reference or
9669 std::initializer_list type. Create, push and return a new VAR_DECL
9670 for the initializer so that it will live as long as DECL. Any
9671 cleanup for the new variable is returned through CLEANUP, and the
9672 code to initialize the new variable is returned through INITP. */
9674 static tree
9677 {
9678 tree init;
9679 tree type;
9680 tree var;
9682 /* Create the temporary variable. */
9686 /* If the rvalue is the result of a function call it will be
9687 a TARGET_EXPR. If it is some other construct (such as a
9688 member access expression where the underlying object is
9689 itself the result of a function call), turn it into a
9690 TARGET_EXPR here. It is important that EXPR be a
9691 TARGET_EXPR below since otherwise the INIT_EXPR will
9692 attempt to make a bitwise copy of EXPR to initialize
9693 VAR. */
9699 {
9703 }
9705 /* Recursively extend temps in this initializer. */
9709 /* Any reference temp has a non-trivial initializer. */
9712 /* If the initializer is constant, put it in DECL_INITIAL so we get
9713 static initialization and use in constant expressions. */
9716 {
9718 {
9719 /* 5.19 says that a constant expression can include an
9720 lvalue-rvalue conversion applied to "a glvalue of literal type
9721 that refers to a non-volatile temporary object initialized
9722 with a constant expression". Rather than try to communicate
9723 that this VAR_DECL is a temporary, just mark it constexpr.
9725 Currently this is only useful for initializer_list temporaries,
9726 since reference vars can't appear in constant expressions. */
9730 }
9733 }
9734 else
9735 /* Create the INIT_EXPR that will initialize the temporary
9736 variable. */
9739 {
9744 else
9745 {
9749 }
9751 /* We must be careful to destroy the temporary only
9752 after its initialization has taken place. If the
9753 initialization throws an exception, then the
9754 destructor should not be run. We cannot simply
9755 transform INIT into something like:
9757 (INIT, ({ CLEANUP_STMT; }))
9759 because emit_local_var always treats the
9760 initializer as a full-expression. Thus, the
9761 destructor would run too early; it would run at the
9762 end of initializing the reference variable, rather
9763 than at the end of the block enclosing the
9764 reference variable.
9766 The solution is to pass back a cleanup expression
9767 which the caller is responsible for attaching to
9768 the statement tree. */
9769 }
9770 else
9771 {
9774 {
9777 tls_aggregates);
9778 else
9780 static_aggregates);
9781 }
9782 else
9783 /* Check whether the dtor is callable. */
9785 }
9786 /* Avoid -Wunused-variable warning (c++/38958). */
9793 }
9795 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
9796 initializing a variable of that TYPE. */
9798 tree
9801 {
9809 /* Get the high-water mark for the CONVERSION_OBSTACK. */
9815 {
9817 {
9826 else
9830 }
9832 }
9835 /* Perform the conversion. */
9838 /* We gave an error in build_user_type_conversion_1. */
9840 else
9843 /* Free all the conversions we allocated. */
9847 }
9849 /* Subroutine of extend_ref_init_temps. Possibly extend one initializer,
9850 which is bound either to a reference or a std::initializer_list. */
9852 static tree
9854 {
9859 {
9863 }
9866 /* Deal with binding to a subobject. */
9870 {
9878 }
9880 }
9882 /* INIT is part of the initializer for DECL. If there are any
9883 reference or initializer lists being initialized, extend their
9884 lifetime to match that of DECL. */
9886 tree
9888 {
9895 {
9896 /* The temporary array underlying a std::initializer_list
9897 is handled like a reference temporary. */
9902 {
9906 }
9907 }
9909 {
9915 }
9918 }
9920 /* Returns true iff an initializer for TYPE could contain temporaries that
9921 need to be extended because they are bound to references or
9922 std::initializer_list. */
9924 bool
9926 {
9931 {
9938 }
9940 }
9942 /* Returns true iff TYPE is some variant of std::initializer_list. */
9944 bool
9946 {
9947 /* Look through typedefs. */
9956 }
9958 /* Returns true iff DECL is a list constructor: i.e. a constructor which
9959 will accept an argument list of a single std::initializer_list<T>. */
9961 bool
9963 {
9965 tree arg;
9977 /* There are more non-defaulted parms. */
9981 }