| blob | eb7247dad93fbde156fe1d9ff91d43cd7a265eef |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann (tiemann@cygnus.com) and
6 modified by Brendan Kehoe (brendan@cygnus.com).
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3, or (at your option)
13 any later version.
15 GCC is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
25 /* High-level class interface. */
42 /* The various kinds of conversion. */
45 ck_identity,
46 ck_lvalue,
47 ck_qual,
48 ck_std,
49 ck_ptr,
50 ck_pmem,
51 ck_base,
52 ck_ref_bind,
53 ck_user,
54 ck_ambig,
55 ck_list,
56 ck_aggr,
57 ck_rvalue
60 /* The rank of the conversion. Order of the enumerals matters; better
61 conversions should come earlier in the list. */
64 cr_identity,
65 cr_exact,
66 cr_promotion,
67 cr_std,
68 cr_pbool,
69 cr_user,
70 cr_ellipsis,
71 cr_bad
74 /* An implicit conversion sequence, in the sense of [over.best.ics].
75 The first conversion to be performed is at the end of the chain.
76 That conversion is always a cr_identity conversion. */
80 /* The kind of conversion represented by this step. */
81 conversion_kind kind;
82 /* The rank of this conversion. */
83 conversion_rank rank;
88 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
89 temporary should be created to hold the result of the
90 conversion. */
92 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
93 from a pointer-to-derived to pointer-to-base is being performed. */
95 /* If KIND is ck_ref_bind, true when either an lvalue reference is
96 being bound to an lvalue expression or an rvalue reference is
97 being bound to an rvalue expression. */
100 /* The type of the expression resulting from the conversion. */
101 tree type;
103 /* The next conversion in the chain. Since the conversions are
104 arranged from outermost to innermost, the NEXT conversion will
105 actually be performed before this conversion. This variant is
106 used only when KIND is neither ck_identity nor ck_ambig. */
108 /* The expression at the beginning of the conversion chain. This
109 variant is used only if KIND is ck_identity or ck_ambig. */
110 tree expr;
111 /* The array of conversions for an initializer_list. */
114 /* The function candidate corresponding to this conversion
115 sequence. This field is only used if KIND is ck_user. */
117 };
119 #define CONVERSION_RANK(NODE) \
120 ((NODE)->bad_p ? cr_bad \
121 : (NODE)->ellipsis_p ? cr_ellipsis \
122 : (NODE)->user_conv_p ? cr_user \
123 : (NODE)->rank)
125 #define BAD_CONVERSION_RANK(NODE) \
126 ((NODE)->ellipsis_p ? cr_ellipsis \
127 : (NODE)->user_conv_p ? cr_user \
128 : (NODE)->rank)
139 #define convert_like(CONV, EXPR, COMPLAIN) \
140 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
143 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
144 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
167 static void add_builtin_candidates
170 static void add_builtin_candidate
174 static void build_builtin_candidate
179 tree);
209 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
210 NAME can take many forms... */
212 bool
214 {
215 /* Just accept something we've already complained about. */
224 {
230 else
232 }
233 else
234 {
235 /* In the case of:
237 template <class T> struct S { ~S(); };
238 int i;
239 i.~S();
241 NAME will be a class template. */
244 }
249 }
251 /* We want the address of a function or method. We avoid creating a
252 pointer-to-member function. */
254 tree
256 {
259 /* We have to do these by hand to avoid real pointer to member
260 functions. */
262 {
264 {
268 }
270 }
271 else
275 }
277 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
278 POINTER_TYPE to those. Note, pointer to member function types
279 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
280 two variants. build_call_a is the primitive taking an array of
281 arguments, while build_call_n is a wrapper that handles varargs. */
283 tree
285 {
288 else
289 {
299 }
300 }
302 tree
304 {
307 tree decl;
308 tree result_type;
309 tree fntype;
319 /* An rvalue has no cv-qualifiers. */
325 {
328 {
329 /* We invoke build_call directly for several library
330 functions. These may have been declared normally if
331 we're building libgcc, so we can't just check
332 DECL_ARTIFICIAL. */
337 }
338 }
339 else
342 /* We check both the decl and the type; a function may be known not to
343 throw without being declared throw(). */
357 /* Don't pass empty class objects by value. This is useful
358 for tags in STL, which are used to control overload resolution.
359 We don't need to handle other cases of copying empty classes. */
364 {
368 }
376 }
378 /* Build something of the form ptr->method (args)
379 or object.method (args). This can also build
380 calls to constructors, and find friends.
382 Member functions always take their class variable
383 as a pointer.
385 INSTANCE is a class instance.
387 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
389 PARMS help to figure out what that NAME really refers to.
391 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
392 down to the real instance type to use for access checking. We need this
393 information to get protected accesses correct.
395 FLAGS is the logical disjunction of zero or more LOOKUP_
396 flags. See cp-tree.h for more info.
398 If this is all OK, calls build_function_call with the resolved
399 member function.
401 This function must also handle being called to perform
402 initialization, promotion/coercion of arguments, and
403 instantiation of default parameters.
405 Note that NAME may refer to an instance variable name. If
406 `operator()()' is defined for the type of that field, then we return
407 that result. */
409 /* New overloading code. */
417 };
420 /* The FUNCTION_DECL that will be called if this candidate is
421 selected by overload resolution. */
422 tree fn;
423 /* If not NULL_TREE, the first argument to use when calling this
424 function. */
425 tree first_arg;
426 /* The rest of the arguments to use when calling this function. If
427 there are no further arguments this may be NULL or it may be an
428 empty vector. */
430 /* The implicit conversion sequences for each of the arguments to
431 FN. */
433 /* The number of implicit conversion sequences. */
435 /* If FN is a user-defined conversion, the standard conversion
436 sequence from the type returned by FN to the desired destination
437 type. */
440 /* If FN is a member function, the binfo indicating the path used to
441 qualify the name of FN at the call site. This path is used to
442 determine whether or not FN is accessible if it is selected by
443 overload resolution. The DECL_CONTEXT of FN will always be a
444 (possibly improper) base of this binfo. */
445 tree access_path;
446 /* If FN is a non-static member function, the binfo indicating the
447 subobject to which the `this' pointer should be converted if FN
448 is selected by overload resolution. The type pointed to the by
449 the `this' pointer must correspond to the most derived class
450 indicated by the CONVERSION_PATH. */
451 tree conversion_path;
452 tree template_decl;
453 tree explicit_targs;
456 };
458 /* Returns true iff T is a null pointer constant in the sense of
459 [conv.ptr]. */
461 bool
463 {
464 /* [conv.ptr]
466 A null pointer constant is an integral constant expression
467 (_expr.const_) rvalue of integer type that evaluates to zero or
468 an rvalue of type std::nullptr_t. */
472 {
474 {
479 }
480 else
481 {
486 }
487 }
489 }
491 /* Returns nonzero if PARMLIST consists of only default parms and/or
492 ellipsis. */
494 bool
496 {
502 }
504 /* Allocate N bytes of memory from the conversion obstack. The memory
505 is zeroed before being returned. */
509 {
512 {
515 }
519 }
521 /* Dynamically allocate a conversion. */
525 {
530 }
532 #ifdef ENABLE_CHECKING
534 /* Make sure that all memory on the conversion obstack has been
535 freed. */
537 void
539 {
543 }
547 /* Dynamically allocate an array of N conversions. */
551 {
553 }
557 {
561 /* Note that the caller is responsible for filling in t->cand for
562 user-defined conversions. */
568 {
584 }
590 }
592 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
593 specialization of std::initializer_list<T>, if such a conversion is
594 possible. */
598 {
604 tree val;
606 /* Within a list-initialization we can have more user-defined
607 conversions. */
609 /* But no narrowing conversions. */
613 {
614 conversion *sub
621 }
629 {
637 }
640 }
642 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
643 is a valid aggregate initializer for array type ATYPE. */
645 static bool
647 {
651 {
657 else
661 }
663 }
665 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
666 aggregate class, if such a conversion is possible. */
670 {
677 {
679 tree val;
684 else
685 {
689 }
695 else
703 }
714 }
716 /* Build a representation of the identity conversion from EXPR to
717 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
721 {
729 }
731 /* Converting from EXPR to TYPE was ambiguous in the sense that there
732 were multiple user-defined conversions to accomplish the job.
733 Build a conversion that indicates that ambiguity. */
737 {
745 }
747 tree
749 {
753 }
755 /* Returns the standard conversion path (see [conv]) from type FROM to type
756 TO, if any. For proper handling of null pointer constants, you must
757 also pass the expression EXPR to convert from. If C_CAST_P is true,
758 this conversion is coming from a C-style cast. */
763 {
770 {
773 }
779 {
787 }
794 {
798 }
800 {
802 {
803 tree bitfield_type;
806 {
809 }
810 }
812 }
814 /* Allow conversion between `__complex__' data types. */
816 {
817 /* The standard conversion sequence to convert FROM to TO is
818 the standard conversion sequence to perform componentwise
819 conversion. */
824 {
827 }
828 else
832 }
837 /* [conv.ptr]
838 A null pointer constant can be converted to a pointer type; ... A
839 null pointer constant of integral type can be converted to an
840 rvalue of type std::nullptr_t. */
847 {
848 /* For backwards brain damage compatibility, allow interconversion of
849 pointers and integers with a pedwarn. */
852 }
854 {
855 /* For backwards brain damage compatibility, allow interconversion of
856 enums and integers with a pedwarn. */
859 }
862 {
863 tree to_pointee;
864 tree from_pointee;
869 ;
873 {
877 from = build_pointer_type
881 }
883 {
888 && (same_type_ignoring_top_level_qualifiers_p
891 {
895 }
898 }
901 /* [conv.ptr]
903 An rvalue of type "pointer to cv D," where D is a
904 class type, can be converted to an rvalue of type
905 "pointer to cv B," where B is a base class (clause
906 _class.derived_) of D. If B is an inaccessible
907 (clause _class.access_) or ambiguous
908 (_class.member.lookup_) base class of D, a program
909 that necessitates this conversion is ill-formed.
910 Therefore, we use DERIVED_FROM_P, and do not check
911 access or uniqueness. */
913 {
914 from =
920 }
923 {
926 }
927 else
928 {
931 }
936 /* In a C-style cast, we ignore CV-qualification because we
937 are allowed to perform a static_cast followed by a
938 const_cast. */
943 /* converting from string constant to char *. */
945 /* Allow conversions among compatible ObjC pointer types (base
946 conversions have been already handled above). */
951 {
954 }
955 else
959 }
961 {
978 }
980 {
981 /* [conv.bool]
983 An rvalue of arithmetic, unscoped enumeration, pointer, or
984 pointer to member type can be converted to an rvalue of type
985 bool. ... An rvalue of type std::nullptr_t can be converted
986 to an rvalue of type bool; */
992 {
1001 }
1004 }
1005 /* We don't check for ENUMERAL_TYPE here because there are no standard
1006 conversions to enum type. */
1007 /* As an extension, allow conversion to complex type. */
1009 {
1015 /* Give this a better rank if it's a promotion. */
1019 }
1025 {
1029 /* The derived-to-base conversion indicates the initialization
1030 of a parameter with base type from an object of a derived
1031 type. A temporary object is created to hold the result of
1032 the conversion unless we're binding directly to a reference. */
1034 }
1035 else
1042 }
1044 /* Returns nonzero if T1 is reference-related to T2. */
1046 bool
1048 {
1055 /* [dcl.init.ref]
1057 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1058 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1059 of T2. */
1063 }
1065 /* Returns nonzero if T1 is reference-compatible with T2. */
1067 static bool
1069 {
1070 /* [dcl.init.ref]
1072 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1073 reference-related to T2 and cv1 is the same cv-qualification as,
1074 or greater cv-qualification than, cv2. */
1077 }
1079 /* Determine whether or not the EXPR (of class type S) can be
1080 converted to T as in [over.match.ref]. */
1084 {
1085 tree conversions;
1086 tree first_arg;
1088 tree t;
1100 /* [over.match.ref]
1102 Assuming that "cv1 T" is the underlying type of the reference
1103 being initialized, and "cv S" is the type of the initializer
1104 expression, with S a class type, the candidate functions are
1105 selected as follows:
1107 --The conversion functions of S and its base classes are
1108 considered. Those that are not hidden within S and yield type
1109 "reference to cv2 T2", where "cv1 T" is reference-compatible
1110 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
1112 The argument list has one argument, which is the initializer
1113 expression. */
1117 /* Conceptually, we should take the address of EXPR and put it in
1118 the argument list. Unfortunately, however, that can result in
1119 error messages, which we should not issue now because we are just
1120 trying to find a conversion operator. Therefore, we use NULL,
1121 cast to the appropriate type. */
1126 /* We're performing a user-defined conversion to a desired type, so set
1127 this for the benefit of add_candidates. */
1131 {
1142 {
1143 /* Now, see if the conversion function really returns
1144 an lvalue of the appropriate type. From the
1145 point of view of unification, simply returning an
1146 rvalue of the right type is good enough. */
1151 {
1153 }
1154 else
1155 {
1157 /* Build a standard conversion sequence indicating the
1158 binding from the reference type returned by the
1159 function to the desired REFERENCE_TYPE. */
1160 identity_conv
1163 NULL_TREE);
1164 cand->second_conv
1165 = (direct_reference_binding
1172 /* Don't allow binding of lvalues to rvalue references. */
1176 }
1177 }
1178 }
1181 /* If none of the conversion functions worked out, let our caller
1182 know. */
1190 /* Now that we know that this is the function we're going to use fix
1191 the dummy first argument. */
1196 /* Build a user-defined conversion sequence representing the
1197 conversion. */
1206 /* Merge it with the standard conversion sequence from the
1207 conversion function's return type to the desired type. */
1211 }
1213 /* A reference of the indicated TYPE is being bound directly to the
1214 expression represented by the implicit conversion sequence CONV.
1215 Return a conversion sequence for this binding. */
1219 {
1220 tree t;
1227 /* [over.ics.rank]
1229 When a parameter of reference type binds directly
1230 (_dcl.init.ref_) to an argument expression, the implicit
1231 conversion sequence is the identity conversion, unless the
1232 argument expression has a type that is a derived class of the
1233 parameter type, in which case the implicit conversion sequence is
1234 a derived-to-base Conversion.
1236 If the parameter binds directly to the result of applying a
1237 conversion function to the argument expression, the implicit
1238 conversion sequence is a user-defined conversion sequence
1239 (_over.ics.user_), with the second standard conversion sequence
1240 either an identity conversion or, if the conversion function
1241 returns an entity of a type that is a derived class of the
1242 parameter type, a derived-to-base conversion. */
1244 {
1245 /* Represent the derived-to-base conversion. */
1247 /* We will actually be binding to the base-class subobject in
1248 the derived class, so we mark this conversion appropriately.
1249 That way, convert_like knows not to generate a temporary. */
1251 }
1253 }
1255 /* Returns the conversion path from type FROM to reference type TO for
1256 purposes of reference binding. For lvalue binding, either pass a
1257 reference type to FROM or an lvalue expression to EXPR. If the
1258 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1259 the conversion returned. If C_CAST_P is true, this
1260 conversion is coming from a C-style cast. */
1264 {
1268 tree tfrom;
1274 {
1279 }
1282 {
1283 /* Anything with reference type is an lvalue. */
1286 }
1289 {
1292 flags);
1295 {
1300 }
1301 }
1310 /* Figure out whether or not the types are reference-related and
1311 reference compatible. We have do do this after stripping
1312 references from FROM. */
1314 /* If this is a C cast, first convert to an appropriately qualified
1315 type, so that we can later do a const_cast to the desired type. */
1321 /* Directly bind reference when target expression's type is compatible with
1322 the reference and expression is an lvalue. In DR391, the wording in
1323 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1324 const and rvalue references to rvalues of compatible class type.
1325 We should also do direct bindings for non-class "rvalues" derived from
1326 rvalue references. */
1328 && (is_lvalue
1333 {
1334 /* [dcl.init.ref]
1336 If the initializer expression
1338 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1339 is reference-compatible with "cv2 T2,"
1341 the reference is bound directly to the initializer expression
1342 lvalue.
1344 [...]
1345 If the initializer expression is an rvalue, with T2 a class type,
1346 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1347 is bound to the object represented by the rvalue or to a sub-object
1348 within that object. */
1354 /* The top-level caller requested that we pretend that the lvalue
1355 be treated as an rvalue. */
1357 else
1358 conv->rvaluedness_matches_p
1363 /* For the purposes of overload resolution, we ignore the fact
1364 this expression is a bitfield or packed field. (In particular,
1365 [over.ics.ref] says specifically that a function with a
1366 non-const reference parameter is viable even if the
1367 argument is a bitfield.)
1369 However, when we actually call the function we must create
1370 a temporary to which to bind the reference. If the
1371 reference is volatile, or isn't const, then we cannot make
1372 a temporary, so we just issue an error when the conversion
1373 actually occurs. */
1376 /* Don't allow binding of lvalues to rvalue references. */
1382 }
1383 /* [class.conv.fct] A conversion function is never used to convert a
1384 (possibly cv-qualified) object to the (possibly cv-qualified) same
1385 object type (or a reference to it), to a (possibly cv-qualified) base
1386 class of that type (or a reference to it).... */
1389 {
1390 /* [dcl.init.ref]
1392 If the initializer expression
1394 -- has a class type (i.e., T2 is a class type) can be
1395 implicitly converted to an lvalue of type "cv3 T3," where
1396 "cv1 T1" is reference-compatible with "cv3 T3". (this
1397 conversion is selected by enumerating the applicable
1398 conversion functions (_over.match.ref_) and choosing the
1399 best one through overload resolution. (_over.match_).
1401 the reference is bound to the lvalue result of the conversion
1402 in the second case. */
1406 }
1408 /* From this point on, we conceptually need temporaries, even if we
1409 elide them. Only the cases above are "direct bindings". */
1413 /* [over.ics.rank]
1415 When a parameter of reference type is not bound directly to an
1416 argument expression, the conversion sequence is the one required
1417 to convert the argument expression to the underlying type of the
1418 reference according to _over.best.ics_. Conceptually, this
1419 conversion sequence corresponds to copy-initializing a temporary
1420 of the underlying type with the argument expression. Any
1421 difference in top-level cv-qualification is subsumed by the
1422 initialization itself and does not constitute a conversion. */
1424 /* [dcl.init.ref]
1426 Otherwise, the reference shall be to a non-volatile const type.
1428 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1432 /* [dcl.init.ref]
1434 Otherwise, a temporary of type "cv1 T1" is created and
1435 initialized from the initializer expression using the rules for a
1436 non-reference copy initialization. If T1 is reference-related to
1437 T2, cv1 must be the same cv-qualification as, or greater
1438 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1442 /* We're generating a temporary now, but don't bind any more in the
1443 conversion (specifically, don't slice the temporary returned by a
1444 conversion operator). */
1447 /* Core issue 899: When [copy-]initializing a temporary to be bound
1448 to the first parameter of a copy constructor (12.8) called with
1449 a single argument in the context of direct-initialization,
1450 explicit conversion functions are also considered.
1452 So don't set LOOKUP_ONLYCONVERTING in that case. */
1458 flags);
1463 /* This reference binding, unlike those above, requires the
1464 creation of a temporary. */
1469 }
1471 /* Returns the implicit conversion sequence (see [over.ics]) from type
1472 FROM to type TO. The optional expression EXPR may affect the
1473 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1474 true, this conversion is coming from a C-style cast. */
1479 {
1491 else
1498 {
1502 /* Allow conversion from an initializer-list with one element to a
1503 scalar type. */
1505 {
1507 tree elt;
1513 else
1519 {
1522 /* Too many levels of braces, i.e. '{{1}}'. */
1525 }
1526 }
1527 }
1533 {
1547 /* We used to try to bind a reference to a temporary here, but that
1548 is now handled after the recursive call to this function at the end
1549 of reference_binding. */
1551 }
1554 }
1556 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1557 functions. ARGS will not be changed until a single candidate is
1558 selected. */
1566 {
1582 }
1584 /* Create an overload candidate for the function or method FN called
1585 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1586 FLAGS is passed on to implicit_conversion.
1588 This does not change ARGS.
1590 CTYPE, if non-NULL, is the type we want to pretend this function
1591 comes from for purposes of overload resolution. */
1598 {
1602 tree parmnode;
1607 /* At this point we should not see any functions which haven't been
1608 explicitly declared, except for friend functions which will have
1609 been found using argument dependent lookup. */
1612 /* The `this', `in_chrg' and VTT arguments to constructors are not
1613 considered in overload resolution. */
1615 {
1619 {
1622 }
1623 }
1624 else
1630 /* 13.3.2 - Viable functions [over.match.viable]
1631 First, to be a viable function, a candidate function shall have enough
1632 parameters to agree in number with the arguments in the list.
1634 We need to check this first; otherwise, checking the ICSes might cause
1635 us to produce an ill-formed template instantiation. */
1639 {
1643 }
1648 /* Make sure there are default args for the rest of the parms. */
1652 /* Kludge: When looking for a function from a subobject while generating
1653 an implicit copy/move constructor/operator=, don't consider anything
1654 that takes (a reference to) an unrelated type. See c++/44909. */
1657 || (current_function_decl
1659 {
1665 else
1668 {
1671 ctype))
1673 }
1674 }
1679 /* Second, for F to be a viable function, there shall exist for each
1680 argument an implicit conversion sequence that converts that argument
1681 to the corresponding parameter of F. */
1686 {
1696 else
1705 {
1711 /* The type of the implicit object parameter ('this') for
1712 overload resolution is not always the same as for the
1713 function itself; conversion functions are considered to
1714 be members of the class being converted, and functions
1715 introduced by a using-declaration are considered to be
1716 members of the class that uses them.
1718 Since build_over_call ignores the ICS for the `this'
1719 parameter, we can just change the parm type. */
1721 {
1722 parmtype = cp_build_qualified_type
1725 }
1727 /* Core issue 899: When [copy-]initializing a temporary to be bound
1728 to the first parameter of a copy constructor (12.8) called with
1729 a single argument in the context of direct-initialization,
1730 explicit conversion functions are also considered.
1732 So set LOOKUP_COPY_PARM to let reference_binding know that
1733 it's being called in that context. We generalize the above
1734 to handle move constructors and template constructors as well;
1735 the standardese should soon be updated similarly. */
1740 && (same_type_ignoring_top_level_qualifiers_p
1742 {
1744 /* We allow user-defined conversions within init-lists, but
1745 not for the copy constructor. */
1748 }
1749 else
1754 }
1755 else
1756 {
1759 }
1766 {
1769 }
1773 }
1775 out:
1778 }
1780 /* Create an overload candidate for the conversion function FN which will
1781 be invoked for expression OBJ, producing a pointer-to-function which
1782 will in turn be called with the argument list FIRST_ARG/ARGLIST,
1783 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
1784 passed on to implicit_conversion.
1786 Actually, we don't really care about FN; we care about the type it
1787 converts to. There may be multiple conversion functions that will
1788 convert to that type, and we rely on build_user_type_conversion_1 to
1789 choose the best one; so when we create our candidate, we record the type
1790 instead of the function. */
1796 {
1812 /* Don't bother looking up the same type twice. */
1817 {
1825 else
1832 flags);
1838 else
1839 {
1842 }
1856 }
1866 }
1868 static void
1872 {
1885 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
1886 conversion ops are allowed. We handle that here by just checking for
1887 boolean_type_node because other operators don't ask for it. COND_EXPR
1888 also does contextual conversion to bool for the first operand, but we
1889 handle that in build_conditional_expr, and type1 here is operand 2. */
1894 {
1901 {
1903 /* We need something for printing the candidate. */
1905 }
1909 }
1911 /* For COND_EXPR we rearranged the arguments; undo that now. */
1913 {
1920 else
1922 }
1928 viable);
1929 }
1931 static bool
1933 {
1935 }
1937 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1939 static bool
1941 {
1942 /* [over.built]
1944 In this section, the term promoted integral type is used to refer
1945 to those integral types which are preserved by integral promotion
1946 (including e.g. int and long but excluding e.g. char).
1947 Similarly, the term promoted arithmetic type refers to promoted
1948 integral types plus floating types. */
1952 }
1954 /* Create any builtin operator overload candidates for the operator in
1955 question given the converted operand types TYPE1 and TYPE2. The other
1956 args are passed through from add_builtin_candidates to
1957 build_builtin_candidate.
1959 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1960 If CODE is requires candidates operands of the same type of the kind
1961 of which TYPE1 and TYPE2 are, we add both candidates
1962 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1964 static void
1968 {
1970 {
1978 }
1981 {
1983 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1984 and VQ is either volatile or empty, there exist candidate operator
1985 functions of the form
1986 VQ T& operator++(VQ T&);
1987 T operator++(VQ T&, int);
1988 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1989 type other than bool, and VQ is either volatile or empty, there exist
1990 candidate operator functions of the form
1991 VQ T& operator--(VQ T&);
1992 T operator--(VQ T&, int);
1993 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1994 complete object type, and VQ is either volatile or empty, there exist
1995 candidate operator functions of the form
1996 T*VQ& operator++(T*VQ&);
1997 T*VQ& operator--(T*VQ&);
1998 T* operator++(T*VQ&, int);
1999 T* operator--(T*VQ&, int); */
2008 {
2011 }
2014 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
2015 exist candidate operator functions of the form
2017 T& operator*(T*);
2019 8 For every function type T, there exist candidate operator functions of
2020 the form
2021 T& operator*(T*); */
2030 /* 9 For every type T, there exist candidate operator functions of the form
2031 T* operator+(T*);
2033 10For every promoted arithmetic type T, there exist candidate operator
2034 functions of the form
2035 T operator+(T);
2036 T operator-(T); */
2046 /* 11For every promoted integral type T, there exist candidate operator
2047 functions of the form
2048 T operator~(T); */
2055 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2056 is the same type as C2 or is a derived class of C2, T is a complete
2057 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2058 there exist candidate operator functions of the form
2059 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2060 where CV12 is the union of CV1 and CV2. */
2065 {
2073 }
2076 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2077 didate operator functions of the form
2078 LR operator*(L, R);
2079 LR operator/(L, R);
2080 LR operator+(L, R);
2081 LR operator-(L, R);
2082 bool operator<(L, R);
2083 bool operator>(L, R);
2084 bool operator<=(L, R);
2085 bool operator>=(L, R);
2086 bool operator==(L, R);
2087 bool operator!=(L, R);
2088 where LR is the result of the usual arithmetic conversions between
2089 types L and R.
2091 14For every pair of types T and I, where T is a cv-qualified or cv-
2092 unqualified complete object type and I is a promoted integral type,
2093 there exist candidate operator functions of the form
2094 T* operator+(T*, I);
2095 T& operator[](T*, I);
2096 T* operator-(T*, I);
2097 T* operator+(I, T*);
2098 T& operator[](I, T*);
2100 15For every T, where T is a pointer to complete object type, there exist
2101 candidate operator functions of the form112)
2102 ptrdiff_t operator-(T, T);
2104 16For every pointer or enumeration type T, there exist candidate operator
2105 functions of the form
2106 bool operator<(T, T);
2107 bool operator>(T, T);
2108 bool operator<=(T, T);
2109 bool operator>=(T, T);
2110 bool operator==(T, T);
2111 bool operator!=(T, T);
2113 17For every pointer to member type T, there exist candidate operator
2114 functions of the form
2115 bool operator==(T, T);
2116 bool operator!=(T, T); */
2123 {
2126 }
2139 {
2142 }
2144 {
2147 }
2148 /* Fall through. */
2165 {
2168 }
2172 {
2175 }
2183 {
2186 }
2188 {
2191 }
2194 /* 18For every pair of promoted integral types L and R, there exist candi-
2195 date operator functions of the form
2196 LR operator%(L, R);
2197 LR operator&(L, R);
2198 LR operator^(L, R);
2199 LR operator|(L, R);
2200 L operator<<(L, R);
2201 L operator>>(L, R);
2202 where LR is the result of the usual arithmetic conversions between
2203 types L and R. */
2211 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2215 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2216 type, VQ is either volatile or empty, and R is a promoted arithmetic
2217 type, there exist candidate operator functions of the form
2218 VQ L& operator=(VQ L&, R);
2219 VQ L& operator*=(VQ L&, R);
2220 VQ L& operator/=(VQ L&, R);
2221 VQ L& operator+=(VQ L&, R);
2222 VQ L& operator-=(VQ L&, R);
2224 20For every pair T, VQ), where T is any type and VQ is either volatile
2225 or empty, there exist candidate operator functions of the form
2226 T*VQ& operator=(T*VQ&, T*);
2228 21For every pair T, VQ), where T is a pointer to member type and VQ is
2229 either volatile or empty, there exist candidate operator functions of
2230 the form
2231 VQ T& operator=(VQ T&, T);
2233 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2234 unqualified complete object type, VQ is either volatile or empty, and
2235 I is a promoted integral type, there exist candidate operator func-
2236 tions of the form
2237 T*VQ& operator+=(T*VQ&, I);
2238 T*VQ& operator-=(T*VQ&, I);
2240 23For every triple L, VQ, R), where L is an integral or enumeration
2241 type, VQ is either volatile or empty, and R is a promoted integral
2242 type, there exist candidate operator functions of the form
2244 VQ L& operator%=(VQ L&, R);
2245 VQ L& operator<<=(VQ L&, R);
2246 VQ L& operator>>=(VQ L&, R);
2247 VQ L& operator&=(VQ L&, R);
2248 VQ L& operator^=(VQ L&, R);
2249 VQ L& operator|=(VQ L&, R); */
2253 {
2257 {
2260 }
2273 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2286 {
2289 }
2294 }
2299 /* [over.built]
2301 For every pair of promoted arithmetic types L and R, there
2302 exist candidate operator functions of the form
2304 LR operator?(bool, L, R);
2306 where LR is the result of the usual arithmetic conversions
2307 between types L and R.
2309 For every type T, where T is a pointer or pointer-to-member
2310 type, there exist candidate operator functions of the form T
2311 operator?(bool, T, T); */
2315 /* That's OK. */
2318 /* Otherwise, the types should be pointers. */
2323 /* We don't check that the two types are the same; the logic
2324 below will actually create two candidates; one in which both
2325 parameter types are TYPE1, and one in which both parameter
2326 types are TYPE2. */
2331 }
2333 /* If we're dealing with two pointer types or two enumeral types,
2334 we need candidates for both of them. */
2343 {
2344 build_builtin_candidate
2346 build_builtin_candidate
2349 }
2351 build_builtin_candidate
2353 }
2355 tree
2357 {
2365 }
2367 /* There are three conditions of builtin candidates:
2369 1) bool-taking candidates. These are the same regardless of the input.
2370 2) pointer-pair taking candidates. These are generated for each type
2371 one of the input types converts to.
2372 3) arithmetic candidates. According to the standard, we should generate
2373 all of these, but I'm trying not to...
2375 Here we generate a superset of the possible candidates for this particular
2376 case. That is a subset of the full set the standard defines, plus some
2377 other cases which the standard disallows. add_builtin_candidate will
2378 filter out the invalid set. */
2380 static void
2384 {
2388 /* TYPES[i] is the set of possible builtin-operator parameter types
2389 we will consider for the Ith argument. */
2394 {
2397 else
2399 }
2402 {
2403 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2404 and VQ is either volatile or empty, there exist candidate operator
2405 functions of the form
2406 VQ T& operator++(VQ T&); */
2416 /* 24There also exist candidate operator functions of the form
2417 bool operator!(bool);
2418 bool operator&&(bool, bool);
2419 bool operator||(bool, bool); */
2422 build_builtin_candidate
2429 build_builtin_candidate
2447 /* Fall through. */
2451 }
2457 {
2459 ;
2461 {
2462 tree convs;
2471 {
2478 }
2484 {
2497 {
2503 }
2507 }
2508 }
2509 else
2510 {
2516 {
2522 }
2524 }
2525 }
2527 /* Run through the possible parameter types of both arguments,
2528 creating candidates with those parameter types. */
2530 {
2532 tree u;
2536 add_builtin_candidate
2539 else
2540 add_builtin_candidate
2543 }
2547 }
2550 /* If TMPL can be successfully instantiated as indicated by
2551 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2553 TMPL is the template. EXPLICIT_TARGS are any explicit template
2554 arguments. ARGLIST is the arguments provided at the call-site.
2555 This does not change ARGLIST. The RETURN_TYPE is the desired type
2556 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2557 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2558 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2566 {
2576 tree arg;
2579 tree fn;
2581 /* We don't do deduction on the in-charge parameter, the VTT
2582 parameter or 'this'. */
2584 {
2587 else
2589 }
2594 {
2597 else
2599 }
2609 {
2612 }
2616 {
2619 }
2623 args_without_in_chrg,
2624 nargs_without_in_chrg,
2634 /* In [class.copy]:
2636 A member function template is never instantiated to perform the
2637 copy of a class object to an object of its class type.
2639 It's a little unclear what this means; the standard explicitly
2640 does allow a template to be used to copy a class. For example,
2641 in:
2643 struct A {
2644 A(A&);
2645 template <class T> A(const T&);
2646 };
2647 const A f ();
2648 void g () { A a (f ()); }
2650 the member template will be used to make the copy. The section
2651 quoted above appears in the paragraph that forbids constructors
2652 whose only parameter is (a possibly cv-qualified variant of) the
2653 class type, and a logical interpretation is that the intent was
2654 to forbid the instantiation of member templates which would then
2655 have that form. */
2657 {
2660 ctype))
2662 }
2665 /* Aha, this is a conversion function. */
2668 else
2673 /* This situation can occur if a member template of a template
2674 class is specialized. Then, instantiate_template might return
2675 an instantiation of the specialization, in which case the
2676 DECL_TI_TEMPLATE field will point at the original
2677 specialization. For example:
2679 template <class T> struct S { template <class U> void f(U);
2680 template <> void f(int) {}; };
2681 S<double> sd;
2682 sd.f(3);
2684 Here, TMPL will be template <class U> S<double>::f(U).
2685 And, instantiate template will give us the specialization
2686 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2687 for this will point at template <class T> template <> S<T>::f(int),
2688 so that we can find the definition. For the purposes of
2689 overload resolution, however, we want the original TMPL. */
2691 else
2696 fail:
2699 }
2707 unification_kind_t strict)
2708 {
2709 return
2714 }
2722 tree conversion_path)
2723 {
2724 return
2728 }
2730 /* The CANDS are the set of candidates that were considered for
2731 overload resolution. Return the set of viable candidates, or CANDS
2732 if none are viable. If any of the candidates were viable, set
2733 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
2734 considered viable only if it is strictly viable. */
2740 {
2751 {
2754 {
2760 }
2761 else
2763 }
2766 }
2768 static bool
2770 {
2775 }
2777 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2778 words, it is about to become the "this" pointer for a member
2779 function call. Take the address of the object. */
2781 static tree
2783 {
2784 /* In a template, we are only concerned about the type of the
2785 expression, so we can take a shortcut. */
2790 }
2792 /* Returns true iff functions are equivalent. Equivalent functions are
2793 not '==' only if one is a function-local extern function or if
2794 both are extern "C". */
2798 {
2807 }
2809 /* Print information about one overload candidate CANDIDATE. MSGSTR
2810 is the text to print before the candidate itself.
2812 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2813 to have been run through gettext by the caller. This wart makes
2814 life simpler in print_z_candidates and for the translators. */
2816 static void
2818 {
2820 {
2830 else
2833 }
2840 else
2842 }
2844 static void
2846 {
2855 /* Remove non-viable deleted candidates. */
2858 {
2863 else
2865 }
2866 /* ...if there are any non-deleted ones. */
2870 /* There may be duplicates in the set of candidates. We put off
2871 checking this condition as long as possible, since we have no way
2872 to eliminate duplicates from a set of functions in less than n^2
2873 time. Now we are about to emit an error message, so it is more
2874 permissible to go slowly. */
2876 {
2878 /* Skip builtin candidates and conversion functions. */
2883 {
2887 else
2889 }
2890 }
2895 {
2898 }
2900 }
2902 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2903 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2904 the result of the conversion function to convert it to the final
2905 desired type. Merge the two sequences into a single sequence,
2906 and return the merged sequence. */
2910 {
2915 /* Find the end of the second conversion sequence. */
2920 /* Replace the identity conversion with the user conversion
2921 sequence. */
2924 /* The entire sequence is a user-conversion sequence. */
2928 }
2930 /* Handle overload resolution for initializing an object of class type from
2931 an initializer list. First we look for a suitable constructor that
2932 takes a std::initializer_list; if we don't find one, we then look for a
2933 non-list constructor.
2935 Parameters are as for add_candidates, except that the arguments are in
2936 the form of a CONSTRUCTOR (the initializer list) rather than a VEC, and
2937 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
2939 static void
2946 {
2951 /* For list-initialization we consider explicit constructors, but
2952 give an error if one is selected. */
2954 /* And we don't allow narrowing conversions. We also use this flag to
2955 avoid the copy constructor call for copy-list-initialization. */
2958 /* Always use the default constructor if the list is empty (DR 990). */
2961 ;
2962 /* If the class has a list ctor, try passing the list as a single
2963 argument first, but only consider list ctors. */
2965 {
2973 }
2977 /* We aren't looking for list-ctors anymore. */
2979 /* We allow more user-defined conversions within an init-list. */
2981 /* But not for the copy ctor. */
2987 }
2989 /* Returns the best overload candidate to perform the requested
2990 conversion. This function is used for three the overloading situations
2991 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2992 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2993 per [dcl.init.ref], so we ignore temporary bindings. */
2997 {
3008 /* We represent conversion within a hierarchy using RVALUE_CONV and
3009 BASE_CONV, as specified by [over.best.ics]; these become plain
3010 constructor calls, as specified in [dcl.init]. */
3018 {
3023 {
3024 /* [class.conv.fct] A conversion function is never used to
3025 convert a (possibly cv-qualified) object to the (possibly
3026 cv-qualified) same object type (or a reference to it), to a
3027 (possibly cv-qualified) base class of that type (or a
3028 reference to it)... */
3029 }
3030 else
3033 }
3040 /* It's OK to bind a temporary for converting constructor arguments, but
3041 not in converting the return value of a conversion operator. */
3046 {
3052 /* We should never try to call the abstract or base constructor
3053 from here. */
3058 {
3059 /* List-initialization. */
3063 }
3064 else
3065 {
3070 }
3073 {
3076 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3077 set, then this is copy-initialization. In that case, "The
3078 result of the call is then used to direct-initialize the
3079 object that is the destination of the copy-initialization."
3080 [dcl.init]
3082 We represent this in the conversion sequence with an
3083 rvalue conversion, which means a constructor call. */
3086 cand->second_conv
3088 }
3089 }
3095 {
3099 /* If we are called to convert to a reference type, we are trying to
3100 find an lvalue binding, so don't even consider temporaries. If
3101 we don't find an lvalue binding, the caller will try again to
3102 look for a temporary binding. */
3113 {
3114 conversion *ics
3120 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3121 copy-initialization. In that case, "The result of the
3122 call is then used to direct-initialize the object that is
3123 the destination of the copy-initialization." [dcl.init]
3125 We represent this in the conversion sequence with an
3126 rvalue conversion, which means a constructor call. But
3127 don't add a second rvalue conversion if there's already
3128 one there. Which there really shouldn't be, but it's
3129 harmless since we'd add it here anyway. */
3140 }
3141 }
3149 {
3151 {
3155 }
3162 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3163 ambiguous conversion is no worse than another user-defined
3164 conversion. */
3167 }
3169 /* Build the user conversion sequence. */
3170 conv = build_conv
3177 /* Remember that this was a list-initialization. */
3181 /* Combine it with the second conversion sequence. */
3189 }
3191 tree
3193 {
3198 {
3203 }
3205 }
3207 /* Subroutine of convert_nontype_argument.
3209 EXPR is an argument for a template non-type parameter of integral or
3210 enumeration type. Do any necessary conversions (that are permitted for
3211 non-type arguments) to convert it to the parameter type.
3213 If conversion is successful, returns the converted expression;
3214 otherwise, returns error_mark_node. */
3216 tree
3218 {
3221 tree t;
3228 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3233 LOOKUP_IMPLICIT);
3235 /* for a non-type template-parameter of integral or
3236 enumeration type, integral promotions (4.5) and integral
3237 conversions (4.7) are applied. */
3238 /* It should be sufficient to check the outermost conversion step, since
3239 there are no qualification conversions to integer type. */
3242 {
3243 /* A conversion function is OK. If it isn't constexpr, we'll
3244 complain later that the argument isn't constant. */
3246 /* The lvalue-to-rvalue conversion is OK. */
3259 /* and fall through. */
3264 }
3268 else
3271 /* Free all the conversions we allocated. */
3275 }
3277 /* Do any initial processing on the arguments to a function call. */
3281 {
3283 tree arg;
3286 {
3290 {
3293 }
3296 }
3298 }
3300 /* Perform overload resolution on FN, which is called with the ARGS.
3302 Return the candidate function selected by overload resolution, or
3303 NULL if the event that overload resolution failed. In the case
3304 that overload resolution fails, *CANDIDATES will be the set of
3305 candidates considered, and ANY_VIABLE_P will be set to true or
3306 false to indicate whether or not any of the candidates were
3307 viable.
3309 The ARGS should already have gone through RESOLVE_ARGS before this
3310 function is called. */
3317 {
3325 /* Check FN. */
3332 {
3336 }
3338 /* Add the various candidate functions. */
3343 LOOKUP_NORMAL,
3344 candidates);
3352 }
3354 /* Return an expression for a call to FN (a namespace-scope function,
3355 or a static member function) with the ARGS. This may change
3356 ARGS. */
3358 tree
3360 tsubst_flags_t complain)
3361 {
3365 tree result;
3368 {
3372 }
3374 /* If this function was found without using argument dependent
3375 lookup, then we want to ignore any undeclared friend
3376 functions. */
3378 {
3383 {
3389 }
3390 }
3392 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3398 {
3400 {
3409 else
3414 }
3416 }
3417 else
3420 /* Free all the conversions we allocated. */
3424 }
3426 /* Build a call to a global operator new. FNNAME is the name of the
3427 operator (either "operator new" or "operator new[]") and ARGS are
3428 the arguments provided. This may change ARGS. *SIZE points to the
3429 total number of bytes required by the allocation, and is updated if
3430 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
3431 be used. If this function determines that no cookie should be
3432 used, after all, *COOKIE_SIZE is set to NULL_TREE. If FN is
3433 non-NULL, it will be set, upon return, to the allocation function
3434 called. */
3436 tree
3440 {
3441 tree fns;
3453 /* Based on:
3455 [expr.new]
3457 If this lookup fails to find the name, or if the allocated type
3458 is not a class type, the allocation function's name is looked
3459 up in the global scope.
3461 we disregard block-scope declarations of "operator new". */
3464 /* Figure out what function is being called. */
3467 /* If no suitable function could be found, issue an error message
3468 and give up. */
3470 {
3474 else
3480 }
3482 /* If a cookie is required, add some extra space. Whether
3483 or not a cookie is required cannot be determined until
3484 after we know which function was called. */
3486 {
3489 {
3490 /* In G++ 3.2, the check was implemented incorrectly; it
3491 looked at the placement expression, rather than the
3492 type of the function. */
3495 ptr_type_node))
3497 }
3498 else
3499 {
3500 tree arg_types;
3503 /* Skip the size_t parameter. */
3505 /* Check the remaining parameters (if any). */
3509 ptr_type_node))
3511 }
3512 /* If we need a cookie, adjust the number of bytes allocated. */
3514 {
3515 /* Update the total size. */
3517 /* Update the argument list to reflect the adjusted size. */
3519 }
3520 else
3522 }
3524 /* Tell our caller which function we decided to call. */
3528 /* Build the CALL_EXPR. */
3530 }
3532 /* Build a new call to operator(). This may change ARGS. */
3534 tree
3536 {
3550 {
3552 /* It's no good looking for an overloaded operator() on a
3553 pointer-to-member-function. */
3554 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3556 }
3559 {
3563 }
3564 else
3568 {
3572 }
3574 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3578 {
3586 }
3591 {
3603 {
3610 add_template_conv_candidate
3614 else
3618 }
3619 }
3623 {
3625 {
3629 }
3631 }
3632 else
3633 {
3636 {
3638 {
3642 }
3644 }
3645 /* Since cand->fn will be a type, not a function, for a conversion
3646 function, we must be careful not to unconditionally look at
3647 DECL_NAME here. */
3651 else
3652 {
3654 complain);
3657 }
3658 }
3660 /* Free all the conversions we allocated. */
3664 }
3666 static void
3669 {
3674 else
3678 {
3683 else
3693 else
3702 else
3712 else
3722 else
3725 else
3729 else
3733 }
3734 }
3736 /* Return the implicit conversion sequence that could be used to
3737 convert E1 to E2 in [expr.cond]. */
3741 {
3747 /* [expr.cond]
3749 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3750 implicitly converted (clause _conv_) to the type "reference to
3751 T2", subject to the constraint that in the conversion the
3752 reference must bind directly (_dcl.init.ref_) to E1. */
3754 {
3756 t1,
3757 e1,
3762 }
3764 /* [expr.cond]
3766 If E1 and E2 have class type, and the underlying class types are
3767 the same or one is a base class of the other: E1 can be converted
3768 to match E2 if the class of T2 is the same type as, or a base
3769 class of, the class of T1, and the cv-qualification of T2 is the
3770 same cv-qualification as, or a greater cv-qualification than, the
3771 cv-qualification of T1. If the conversion is applied, E1 is
3772 changed to an rvalue of type T2 that still refers to the original
3773 source class object (or the appropriate subobject thereof). */
3776 {
3778 {
3783 else
3786 }
3787 else
3789 }
3790 else
3791 /* [expr.cond]
3793 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3794 converted to the type that expression E2 would have if E2 were
3795 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3797 LOOKUP_IMPLICIT);
3798 }
3800 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3801 arguments to the conditional expression. */
3803 tree
3805 tsubst_flags_t complain)
3806 {
3807 tree arg2_type;
3808 tree arg3_type;
3816 /* As a G++ extension, the second argument to the conditional can be
3817 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3818 c'.) If the second operand is omitted, make sure it is
3819 calculated only once. */
3821 {
3826 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3829 else
3831 }
3833 /* [expr.cond]
3835 The first expression is implicitly converted to bool (clause
3836 _conv_). */
3838 LOOKUP_NORMAL);
3840 /* If something has already gone wrong, just pass that fact up the
3841 tree. */
3847 /* [expr.cond]
3849 If either the second or the third operand has type (possibly
3850 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3851 array-to-pointer (_conv.array_), and function-to-pointer
3852 (_conv.func_) standard conversions are performed on the second
3853 and third operands. */
3857 {
3858 /* Do the conversions. We don't these for `void' type arguments
3859 since it can't have any effect and since decay_conversion
3860 does not handle that case gracefully. */
3868 /* [expr.cond]
3870 One of the following shall hold:
3872 --The second or the third operand (but not both) is a
3873 throw-expression (_except.throw_); the result is of the
3874 type of the other and is an rvalue.
3876 --Both the second and the third operands have type void; the
3877 result is of type void and is an rvalue.
3879 We must avoid calling force_rvalue for expressions of type
3880 "void" because it will complain that their value is being
3881 used. */
3884 {
3889 }
3892 {
3897 }
3900 else
3901 {
3903 {
3906 "is of type %<void%>, "
3907 "but the third operand is neither a throw-expression "
3909 else
3911 "is of type %<void%>, "
3912 "but the second operand is neither a throw-expression "
3914 }
3916 }
3920 }
3921 /* [expr.cond]
3923 Otherwise, if the second and third operand have different types,
3924 and either has (possibly cv-qualified) class type, an attempt is
3925 made to convert each of those operands to the type of the other. */
3928 {
3932 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3938 /* [expr.cond]
3940 If both can be converted, or one can be converted but the
3941 conversion is ambiguous, the program is ill-formed. If
3942 neither can be converted, the operands are left unchanged and
3943 further checking is performed as described below. If exactly
3944 one conversion is possible, that conversion is applied to the
3945 chosen operand and the converted operand is used in place of
3946 the original operand for the remainder of this section. */
3951 {
3955 }
3957 {
3961 /* Even if CONV2 is a valid conversion, the result of the
3962 conversion may be invalid. For example, if ARG3 has type
3963 "volatile X", and X does not have a copy constructor
3964 accepting a "volatile X&", then even if ARG2 can be
3965 converted to X, the conversion will fail. */
3968 }
3970 {
3976 }
3978 /* Free all the conversions we allocated. */
3984 /* If, after the conversion, both operands have class type,
3985 treat the cv-qualification of both operands as if it were the
3986 union of the cv-qualification of the operands.
3988 The standard is not clear about what to do in this
3989 circumstance. For example, if the first operand has type
3990 "const X" and the second operand has a user-defined
3991 conversion to "volatile X", what is the type of the second
3992 operand after this step? Making it be "const X" (matching
3993 the first operand) seems wrong, as that discards the
3994 qualification without actually performing a copy. Leaving it
3995 as "volatile X" seems wrong as that will result in the
3996 conditional expression failing altogether, even though,
3997 according to this step, the one operand could be converted to
3998 the type of the other. */
4006 }
4008 /* [expr.cond]
4010 If the second and third operands are lvalues and have the same
4011 type, the result is of that type and is an lvalue. */
4015 {
4020 }
4022 /* [expr.cond]
4024 Otherwise, the result is an rvalue. If the second and third
4025 operand do not have the same type, and either has (possibly
4026 cv-qualified) class type, overload resolution is used to
4027 determine the conversions (if any) to be applied to the operands
4028 (_over.match.oper_, _over.built_). */
4032 {
4037 /* Rearrange the arguments so that add_builtin_candidate only has
4038 to know about two args. In build_builtin_candidate, the
4039 arguments are unscrambled. */
4044 COND_EXPR,
4045 NOP_EXPR,
4047 args,
4048 LOOKUP_NORMAL);
4050 /* [expr.cond]
4052 If the overload resolution fails, the program is
4053 ill-formed. */
4056 {
4058 {
4061 }
4063 }
4066 {
4068 {
4071 }
4073 }
4075 /* [expr.cond]
4077 Otherwise, the conversions thus determined are applied, and
4078 the converted operands are used in place of the original
4079 operands for the remainder of this section. */
4088 }
4090 /* [expr.cond]
4092 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4093 and function-to-pointer (_conv.func_) standard conversions are
4094 performed on the second and third operands.
4096 We need to force the lvalue-to-rvalue conversion here for class types,
4097 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4098 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4099 regions. */
4112 /* [expr.cond]
4114 After those conversions, one of the following shall hold:
4116 --The second and third operands have the same type; the result is of
4117 that type. */
4120 /* [expr.cond]
4122 --The second and third operands have arithmetic or enumeration
4123 type; the usual arithmetic conversions are performed to bring
4124 them to a common type, and the result is of that type. */
4129 {
4130 /* In this case, there is always a common type. */
4132 arg3_type);
4134 "implicit conversion from %qT to %qT to "
4136 input_location);
4140 {
4145 }
4151 {
4155 }
4159 }
4160 /* [expr.cond]
4162 --The second and third operands have pointer type, or one has
4163 pointer type and the other is a null pointer constant; pointer
4164 conversions (_conv.ptr_) and qualification conversions
4165 (_conv.qual_) are performed to bring them to their composite
4166 pointer type (_expr.rel_). The result is of the composite
4167 pointer type.
4169 --The second and third operands have pointer to member type, or
4170 one has pointer to member type and the other is a null pointer
4171 constant; pointer to member conversions (_conv.mem_) and
4172 qualification conversions (_conv.qual_) are performed to bring
4173 them to a common type, whose cv-qualification shall match the
4174 cv-qualification of either the second or the third operand.
4175 The result is of the common type. */
4183 {
4186 complain);
4191 }
4194 {
4199 }
4201 valid_operands:
4204 /* Avoid folding within decltype (c++/42013) and noexcept. */
4207 /* We can't use result_type below, as fold might have returned a
4208 throw_expr. */
4211 {
4212 /* Expand both sides into the same slot, hopefully the target of
4213 the ?: expression. We used to check for TARGET_EXPRs here,
4214 but now we sometimes wrap them in NOP_EXPRs so the test would
4215 fail. */
4218 /* If this expression is an rvalue, but might be mistaken for an
4219 lvalue, we must add a NON_LVALUE_EXPR. */
4221 }
4224 }
4226 /* OPERAND is an operand to an expression. Perform necessary steps
4227 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
4228 returned. */
4230 static tree
4232 {
4234 {
4237 /* Make sure the template type is instantiated now. */
4239 }
4242 }
4244 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
4245 OVERLOAD) to the CANDIDATES, returning an updated list of
4246 CANDIDATES. The ARGS are the arguments provided to the call;
4247 if FIRST_ARG is non-null it is the implicit object argument,
4248 otherwise the first element of ARGS is used if needed. The
4249 EXPLICIT_TARGS are explicit template arguments provided.
4250 TEMPLATE_ONLY is true if only template functions should be
4251 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
4252 add_function_candidate. */
4254 static void
4256 tree return_type,
4261 {
4262 tree ctype;
4266 unification_kind_t strict;
4267 tree fn;
4272 /* Precalculate special handling of constructors and conversion ops. */
4275 {
4279 /* We're doing return_type(x). */
4281 else
4282 /* We're doing x.operator return_type(). */
4284 /* [over.match.funcs] For conversion functions, the function
4285 is considered to be a member of the class of the implicit
4286 object argument for the purpose of defining the type of
4287 the implicit object parameter. */
4289 }
4290 else
4291 {
4293 {
4296 }
4297 else
4298 {
4301 }
4304 }
4308 else
4309 /* Delay creating the implicit this parameter until it is needed. */
4313 {
4314 tree fn_first_arg;
4324 /* Figure out which set of arguments to use. */
4326 {
4327 /* If this function is a non-static member and we didn't get an
4328 implicit object argument, move it out of args. */
4330 {
4332 tree arg;
4339 }
4343 }
4344 else
4345 {
4346 /* Otherwise, just use the list of arguments provided. */
4349 }
4353 fn,
4354 ctype,
4355 explicit_targs,
4356 fn_first_arg,
4357 fn_args,
4358 return_type,
4359 access_path,
4360 conversion_path,
4361 flags,
4362 strict);
4365 fn,
4366 ctype,
4367 fn_first_arg,
4368 fn_args,
4369 access_path,
4370 conversion_path,
4371 flags);
4372 }
4373 }
4375 /* Even unsigned enum types promote to signed int. We don't want to
4376 issue -Wsign-compare warnings for this case. Here ORIG_ARG is the
4377 original argument and ARG is the argument after any conversions
4378 have been applied. We set TREE_NO_WARNING if we have added a cast
4379 from an unsigned enum type to a signed integer type. */
4381 static void
4383 {
4392 }
4394 tree
4397 {
4403 tree fnname;
4421 {
4425 }
4426 else
4432 {
4437 /* Use build_op_new_call and build_op_delete_call instead. */
4441 /* Use build_op_call instead. */
4448 /* These are saved for the sake of warn_logical_operator. */
4454 }
4460 /* Use build_conditional_expr instead. */
4476 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4479 /* Add namespace-scope operators to the list of functions to
4480 consider. */
4485 /* Add class-member operators to the candidate set. */
4487 {
4488 tree fns;
4492 {
4495 }
4503 }
4512 {
4515 /* For these, the built-in candidates set is empty
4516 [over.match.oper]/3. We don't want non-strict matches
4517 because exact matches are always possible with built-in
4518 operators. The built-in candidate set for COMPONENT_REF
4519 would be empty too, but since there are no such built-in
4520 operators, we accept non-strict matches for them. */
4527 }
4531 {
4533 {
4536 /* Don't try anything fancy if we're not allowed to produce
4537 errors. */
4541 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
4542 distinguish between prefix and postfix ++ and
4543 operator++() was used for both, so we allow this with
4544 -fpermissive. */
4546 {
4553 }
4560 else
4566 /* The caller will deal with these. */
4576 {
4577 /* If one of the arguments of the operator represents
4578 an invalid use of member function pointer, try to report
4579 a meaningful error ... */
4584 else
4585 {
4586 /* ... Otherwise, report the more generic
4587 "no matching operator found" error */
4590 }
4591 }
4594 }
4595 }
4596 else
4597 {
4600 {
4602 {
4605 }
4607 }
4609 {
4615 else
4617 }
4618 else
4619 {
4620 /* Give any warnings we noticed during overload resolution. */
4622 {
4626 }
4628 /* Check for comparison of different enum types. */
4630 {
4642 {
4646 }
4650 }
4652 /* We need to strip any leading REF_BIND so that bitfields
4653 don't cause errors. This should not remove any important
4654 conversions, because builtins don't apply to class
4655 objects directly. */
4662 {
4663 /* We need to call warn_logical_operator before
4664 converting arg2 to a boolean_type. */
4674 }
4676 {
4681 }
4683 }
4684 }
4686 user_defined_result_ready:
4688 /* Free all the conversions we allocated. */
4694 builtin:
4700 {
4713 /* Fall through. */
4751 complain),
4752 arg2);
4754 /* The caller will deal with these. */
4762 }
4764 }
4766 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
4767 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
4769 static bool
4771 {
4772 /* A template instance is never a usual deallocation function,
4773 regardless of its signature. */
4778 /* If a class T has a member deallocation function named operator delete
4779 with exactly one parameter, then that function is a usual
4780 (non-placement) deallocation function. If class T does not declare
4781 such an operator delete but does declare a member deallocation
4782 function named operator delete with exactly two parameters, the second
4783 of which has type std::size_t (18.2), then this function is a usual
4784 deallocation function. */
4791 }
4793 /* Build a call to operator delete. This has to be handled very specially,
4794 because the restrictions on what signatures match are different from all
4795 other call instances. For a normal delete, only a delete taking (void *)
4796 or (void *, size_t) is accepted. For a placement delete, only an exact
4797 match with the placement new is accepted.
4799 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4800 ADDR is the pointer to be deleted.
4801 SIZE is the size of the memory block to be deleted.
4802 GLOBAL_P is true if the delete-expression should not consider
4803 class-specific delete operators.
4804 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4806 If this call to "operator delete" is being generated as part to
4807 deallocate memory allocated via a new-expression (as per [expr.new]
4808 which requires that if the initialization throws an exception then
4809 we call a deallocation function), then ALLOC_FN is the allocation
4810 function. */
4812 tree
4815 tree alloc_fn)
4816 {
4830 /* In [class.free]
4832 If the result of the lookup is ambiguous or inaccessible, or if
4833 the lookup selects a placement deallocation function, the
4834 program is ill-formed.
4836 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4837 {
4841 }
4842 else
4848 /* Strip const and volatile from addr. */
4852 {
4853 /* "A declaration of a placement deallocation function matches the
4854 declaration of a placement allocation function if it has the same
4855 number of parameters and, after parameter transformations (8.3.5),
4856 all parameter types except the first are identical."
4858 So we build up the function type we want and ask instantiate_type
4859 to get it for us. */
4871 /* "If the lookup finds the two-parameter form of a usual deallocation
4872 function (3.7.4.2) and that function, considered as a placement
4873 deallocation function, would have been selected as a match for the
4874 allocation function, the program is ill-formed." */
4876 {
4877 /* But if the class has an operator delete (void *), then that is
4878 the usual deallocation function, so we shouldn't complain
4879 about using the operator delete (void *, size_t). */
4882 {
4887 }
4890 ok:;
4891 }
4892 }
4893 else
4894 /* "Any non-placement deallocation function matches a non-placement
4895 allocation function. If the lookup finds a single matching
4896 deallocation function, that function will be called; otherwise, no
4897 deallocation function will be called." */
4900 {
4903 {
4905 /* "If a class T has a member deallocation function named
4906 operator delete with exactly one parameter, then that
4907 function is a usual (non-placement) deallocation
4908 function. If class T does not declare such an operator
4909 delete but does declare a member deallocation function named
4910 operator delete with exactly two parameters, the second of
4911 which has type std::size_t (18.2), then this function is a
4912 usual deallocation function."
4914 So (void*) beats (void*, size_t). */
4917 }
4918 }
4920 /* If we have a matching function, call it. */
4922 {
4925 /* If the FN is a member function, make sure that it is
4926 accessible. */
4930 /* Core issue 901: It's ok to new a type with deleted delete. */
4935 {
4936 /* The placement args might not be suitable for overload
4937 resolution at this point, so build the call directly. */
4946 }
4947 else
4948 {
4949 tree ret;
4957 }
4958 }
4960 /* [expr.new]
4962 If no unambiguous matching deallocation function can be found,
4963 propagating the exception does not cause the object's memory to
4964 be freed. */
4966 {
4969 alloc_fn);
4971 }
4976 }
4978 /* If the current scope isn't allowed to access DECL along
4979 BASETYPE_PATH, give an error. The most derived class in
4980 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4981 the declaration to use in the error diagnostic. */
4983 bool
4985 {
4989 {
4994 else
4998 }
5001 }
5003 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
5004 bitwise or of LOOKUP_* values. If any errors are warnings are
5005 generated, set *DIAGNOSTIC_FN to "error" or "warning",
5006 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
5007 to NULL. */
5009 static tree
5012 {
5025 else
5028 }
5030 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
5031 EXPR is implicitly converted to type TOTYPE.
5032 FN and ARGNUM are used for diagnostics. */
5034 static void
5036 {
5039 /* Issue warnings about peculiar, but valid, uses of NULL. */
5041 {
5046 else
5049 }
5051 /* Issue warnings if "false" is converted to a NULL pointer */
5056 }
5058 /* Perform the conversions in CONVS on the expression EXPR. FN and
5059 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
5060 indicates the `this' argument of a method. INNER is nonzero when
5061 being called to continue a conversion chain. It is negative when a
5062 reference binding will be applied, positive otherwise. If
5063 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
5064 conversions will be emitted if appropriate. If C_CAST_P is true,
5065 this conversion is coming from a C-style cast; in that case,
5066 conversions to inaccessible bases are permitted. */
5068 static tree
5072 {
5074 diagnostic_t diag_kind;
5084 {
5087 /* Give a helpful error if this is bad because of excess braces. */
5095 {
5097 {
5101 complain);
5103 }
5108 complain);
5111 }
5113 {
5118 }
5119 else
5123 }
5129 {
5131 {
5138 /* When converting from an init list we consider explicit
5139 constructors, but actually trying to call one is an error. */
5141 /* Unless we're calling it for value-initialization from an
5142 empty list, since that is handled separately in 8.5.4. */
5144 {
5148 else
5150 }
5152 /* Set user_conv_p on the argument conversions, so rvalue/base
5153 handling knows not to allow any more UDCs. */
5159 /* If this is a constructor or a function returning an aggr type,
5160 we need to build up a TARGET_EXPR. */
5162 {
5165 /* Remember that this was list-initialization. */
5168 }
5171 }
5175 {
5181 else
5183 }
5187 /* Convert a constant to its underlying value, unless we are
5188 about to bind it to a reference, in which case we need to
5189 leave it as an lvalue. */
5191 {
5194 /* If __null has been converted to an integer type, we do not
5195 want to warn about uses of EXPR as an integer, rather than
5196 as a pointer. */
5198 }
5202 {
5203 /* Call build_user_type_conversion again for the error. */
5207 }
5211 {
5212 /* Conversion to std::initializer_list<T>. */
5220 /* Convert all the elements. */
5222 {
5230 }
5231 /* Build up the array. */
5232 elttype = cp_build_qualified_type
5240 /* Call the private constructor. */
5242 new_ctor = build_special_member_call
5247 }
5254 };
5259 c_cast_p,
5260 complain);
5265 {
5270 /* Else fall through. */
5273 {
5274 /* We are going to bind a reference directly to a base-class
5275 subobject of EXPR. */
5276 /* Build an expression for `*((base*) &expr)'. */
5282 }
5284 /* Copy-initialization where the cv-unqualified version of the source
5285 type is the same class as, or a derived class of, the class of the
5286 destination [is treated as direct-initialization]. [dcl.init] */
5289 /* This conversion is being done in the context of a user-defined
5290 conversion (i.e. the second step of copy-initialization), so
5291 don't allow any more. */
5295 {
5301 }
5305 {
5310 {
5312 {
5317 }
5319 }
5321 /* If necessary, create a temporary.
5323 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
5324 that need temporaries, even when their types are reference
5325 compatible with the type of reference being bound, so the
5326 upcoming call to cp_build_addr_expr doesn't fail. */
5330 {
5331 /* Otherwise, a temporary of type "cv1 T1" is created and
5332 initialized from the initializer expression using the rules
5333 for a non-reference copy-initialization (8.5). */
5342 {
5344 {
5345 /* If the reference is volatile or non-const, we
5346 cannot create a temporary. */
5353 else
5355 }
5357 }
5358 /* If the source is a packed field, and we must use a copy
5359 constructor, then building the target expr will require
5360 binding the field to the reference parameter to the
5361 copy constructor, and we'll end up with an infinite
5362 loop. If we can use a bitwise copy, then we'll be
5363 OK. */
5367 {
5372 }
5374 {
5377 }
5379 }
5381 /* Take the address of the thing to which we will bind the
5382 reference. */
5387 /* Convert it to a pointer to the type referred to by the
5388 reference. This will adjust the pointer if a derived to
5389 base conversion is being performed. */
5391 expr);
5392 /* Convert the pointer to the desired reference type. */
5394 }
5400 /* Warn about deprecated conversion if appropriate. */
5416 }
5423 else
5427 }
5429 /* ARG is being passed to a varargs function. Perform any conversions
5430 required. Return the converted value. */
5432 tree
5434 {
5435 tree arg_type;
5437 /* [expr.call]
5439 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5440 standard conversions are performed. */
5443 /* [expr.call]
5445 If the argument has integral or enumeration type that is subject
5446 to the integral promotions (_conv.prom_), or a floating point
5447 type that is subject to the floating point promotion
5448 (_conv.fpprom_), the value of the argument is converted to the
5449 promoted type before the call. */
5454 {
5457 "implicit conversion from %qT to %qT when passing "
5461 }
5473 {
5474 /* [expr.call] 5.2.2/7:
5475 Passing a potentially-evaluated argument of class type (Clause 9)
5476 with a non-trivial copy constructor or a non-trivial destructor
5477 with no corresponding parameter is conditionally-supported, with
5478 implementation-defined semantics.
5480 We used to just warn here and do a bitwise copy, but now
5481 cp_expr_size will abort if we try to do that.
5483 If the call appears in the context of a sizeof expression,
5484 it is not potentially-evaluated. */
5488 }
5491 }
5493 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
5495 tree
5497 {
5511 {
5512 /* Remove reference types so we don't ICE later on. */
5514 /* conditionally-supported behavior [expr.call] 5.2.2/7. */
5520 }
5523 }
5525 /* TYPE has been given to va_arg. Apply the default conversions which
5526 would have happened when passed via ellipsis. Return the promoted
5527 type, or the passed type if there is no change. */
5529 tree
5531 {
5532 tree promote;
5534 /* Perform the array-to-pointer and function-to-pointer
5535 conversions. */
5543 }
5545 /* ARG is a default argument expression being passed to a parameter of
5546 the indicated TYPE, which is a parameter to FN. Do any required
5547 conversions. Return the converted value. */
5551 tree
5553 {
5555 tree t;
5557 /* If the ARG is an unparsed default argument expression, the
5558 conversion cannot be performed. */
5560 {
5565 }
5567 /* Detect recursion. */
5570 {
5573 }
5579 /* Due to:
5581 [dcl.fct.default]
5583 The names in the expression are bound, and the semantic
5584 constraints are checked, at the point where the default
5585 expressions appears.
5587 we must not perform access checks here. */
5591 {
5595 tf_warning_or_error);
5596 }
5597 else
5598 {
5599 /* We must make a copy of ARG, in case subsequent processing
5600 alters any part of it. For example, during gimplification a
5601 cast of the form (T) &X::f (where "f" is a member function)
5602 will lead to replacing the PTRMEM_CST for &X::f with a
5603 VAR_DECL. We can avoid the copy for constants, since they
5604 are never modified in place. */
5609 tf_warning_or_error);
5611 }
5617 }
5619 /* Returns the type which will really be used for passing an argument of
5620 type TYPE. */
5622 tree
5624 {
5625 /* Pass classes with copy ctors by invisible reference. */
5627 {
5629 /* There are no other pointers to this temporary. */
5631 }
5640 }
5642 /* Actually perform the appropriate conversion. */
5644 tree
5646 {
5647 tree bitfield_type;
5649 /* If VAL is a bitfield, then -- since it has already been converted
5650 to TYPE -- it cannot have a precision greater than TYPE.
5652 If it has a smaller precision, we must widen it here. For
5653 example, passing "int f:3;" to a function expecting an "int" will
5654 not result in any conversion before this point.
5656 If the precision is the same we must not risk widening. For
5657 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
5658 often have type "int", even though the C++ type for the field is
5659 "long long". If the value is being passed to a function
5660 expecting an "int", then no conversions will be required. But,
5661 if we call convert_bitfield_to_declared_type, the bitfield will
5662 be converted to "long long". */
5669 ;
5670 /* Pass classes with copy ctors by invisible reference. */
5680 {
5689 }
5691 }
5693 /* Returns true iff FN is a function with magic varargs, i.e. ones for
5694 which no conversions at all should be done. This is true for some
5695 builtins which don't act like normal functions. */
5697 static bool
5699 {
5702 {
5712 }
5715 }
5717 /* Subroutine of the various build_*_call functions. Overload resolution
5718 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
5719 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
5720 bitmask of various LOOKUP_* flags which apply to the call itself. */
5722 static tree
5724 {
5732 tree val;
5741 /* In a template, there is no need to perform all of the work that
5742 is normally done. We are only interested in the type of the call
5743 expression, i.e., the return type of the function. Any semantic
5744 errors will be deferred until the template is instantiated. */
5746 {
5747 tree expr;
5748 tree return_type;
5756 else
5757 {
5760 tree arg;
5768 }
5771 argarray);
5777 }
5779 /* Give any warnings we noticed during overload resolution. */
5781 {
5785 }
5787 /* Make =delete work with SFINAE. */
5792 {
5793 tree access_fn;
5794 /* If FN is a template function, two cases must be considered.
5795 For example:
5797 struct A {
5798 protected:
5799 template <class T> void f();
5800 };
5801 template <class T> struct B {
5802 protected:
5803 void g();
5804 };
5805 struct C : A, B<int> {
5806 using A::f; // #1
5807 using B<int>::g; // #2
5808 };
5810 In case #1 where `A::f' is a member template, DECL_ACCESS is
5811 recorded in the primary template but not in its specialization.
5812 We check access of FN using its primary template.
5814 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
5815 because it is a member of class template B, DECL_ACCESS is
5816 recorded in the specialization `B<int>::g'. We cannot use its
5817 primary template because `B<T>::g' and `B<int>::g' may have
5818 different access. */
5822 else
5825 {
5829 }
5830 else
5832 }
5834 /* If we're checking for implicit delete, don't bother with argument
5835 conversions. */
5837 {
5839 {
5843 }
5847 /* Reject bad conversions now. */
5849 /* else continue to get conversion error. */
5850 }
5852 /* Find maximum size of vector to hold converted arguments. */
5859 /* The implicit parameters to a constructor are not considered by overload
5860 resolution, and must be of the proper type. */
5862 {
5864 {
5867 }
5868 else
5869 {
5872 }
5874 /* We should never try to call the abstract constructor. */
5878 {
5882 }
5883 }
5884 /* Bypass access control for 'this' parameter. */
5886 {
5889 ? first_arg
5892 tree converted_arg;
5893 tree base_binfo;
5896 {
5900 else
5902 }
5904 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
5905 X is called for an object that is not of type X, or of a type
5906 derived from X, the behavior is undefined.
5908 So we can assume that anything passed as 'this' is non-null, and
5909 optimize accordingly. */
5911 /* Convert to the base in which the function was declared. */
5914 arg,
5917 /* Check that the base class is accessible. */
5923 /* If fn was found by a using declaration, the conversion path
5924 will be to the derived class, not the base declaring fn. We
5925 must convert from derived to base. */
5935 else
5939 }
5944 {
5950 /* Don't make a copy here if build_call is going to. */
5956 /* Warn about initializer_list deduction that isn't currently in the
5957 working draft. */
5959 && flag_deduce_init_list
5963 {
5976 {
5983 }
5984 }
5991 else
5993 }
5995 /* Default arguments */
6000 /* Ellipsis */
6002 {
6005 /* Do no conversions for magic varargs. */
6007 else
6010 }
6018 /* Avoid actually calling copy constructors and copy assignment operators,
6019 if possible. */
6026 {
6027 tree targ;
6029 tree fa;
6032 /* Pull out the real argument, disregarding const-correctness. */
6038 {
6043 }
6044 else
6049 else
6054 {
6055 /* Copy-list-initialization doesn't require the constructor
6056 to be defined. */
6057 }
6058 /* [class.copy]: the copy constructor is implicitly defined even if
6059 the implementation elided its use. */
6061 {
6064 }
6066 /* If we're creating a temp and we already have one, don't create a
6067 new one. If we're not creating a temp but we get one, use
6068 INIT_EXPR to collapse the temp into our target. Otherwise, if the
6069 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
6070 temp or an INIT_EXPR otherwise. */
6073 {
6078 }
6080 {
6082 complain));
6086 }
6087 }
6090 {
6091 tree to = stabilize_reference
6098 {
6099 /* Avoid copying empty classes. */
6104 }
6106 {
6109 }
6110 else
6111 {
6112 /* We must only copy the non-tail padding parts.
6113 Use __builtin_memcpy for the bitwise copy.
6114 FIXME fix 22488 so we can go back to using MODIFY_EXPR
6115 instead of an explicit call to memcpy. */
6125 {
6126 /* If we can't be sure about pointer alignment, a call
6127 to __builtin_memcpy is expanded as a call to memcpy, which
6128 is invalid with identical args. Otherwise it is
6129 expanded as a block move, which should be safe. */
6133 }
6142 }
6145 }
6146 /* FIXME handle trivial default constructor and destructor, too. */
6152 {
6153 tree t;
6159 /* Warn about deprecated virtual functions now, since we're about
6160 to throw away the decl. */
6170 else
6173 }
6174 else
6178 }
6180 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
6181 This function performs no overload resolution, conversion, or other
6182 high-level operations. */
6184 tree
6186 {
6187 tree fndecl;
6191 /* If this call might throw an exception, note that fact. */
6195 && cfun
6199 /* Check that arguments to builtin functions match the expectations. */
6206 /* Some built-in function calls will be evaluated at compile-time in
6207 fold (). */
6220 }
6224 /* Make an expression which yields the address of the Java interface
6225 method FN. This is achieved by generating a call to libjava's
6226 _Jv_LookupInterfaceMethodIdx(). */
6228 static tree
6230 {
6236 {
6240 java_iface_lookup_fn
6243 }
6245 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
6246 This is the first entry in the vtable. */
6248 tf_warning_or_error),
6249 integer_zero_node);
6251 /* Get the java.lang.Class pointer for the interface being called. */
6256 {
6258 iface);
6260 }
6264 /* Determine the itable index of FN. */
6267 {
6272 i++;
6273 }
6278 java_iface_lookup_fn);
6281 }
6283 /* Returns the value to use for the in-charge parameter when making a
6284 call to a function with the indicated NAME.
6286 FIXME:Can't we find a neater way to do this mapping? */
6288 tree
6290 {
6301 /* This function should only be called with one of the names listed
6302 above. */
6305 }
6307 /* Build a call to a constructor, destructor, or an assignment
6308 operator for INSTANCE, an expression with class type. NAME
6309 indicates the special member function to call; *ARGS are the
6310 arguments. ARGS may be NULL. This may change ARGS. BINFO
6311 indicates the base of INSTANCE that is to be passed as the `this'
6312 parameter to the member function called.
6314 FLAGS are the LOOKUP_* flags to use when processing the call.
6316 If NAME indicates a complete object constructor, INSTANCE may be
6317 NULL_TREE. In this case, the caller will call build_cplus_new to
6318 store the newly constructed object into a VAR_DECL. */
6320 tree
6323 {
6324 tree fns;
6325 /* The type of the subobject to be constructed or destroyed. */
6326 tree class_type;
6328 tree ret;
6337 {
6338 /* Resolve the name. */
6343 }
6349 /* Handle the special case where INSTANCE is NULL_TREE. */
6351 {
6354 }
6355 else
6356 {
6362 /* Convert to the base class, if necessary. */
6365 {
6367 /* For constructors and destructors, either the base is
6368 non-virtual, or it is virtual but we are doing the
6369 conversion from a constructor or destructor for the
6370 complete object. In either case, we can convert
6371 statically. */
6373 else
6374 /* However, for assignment operators, we must convert
6375 dynamically if the base is virtual. */
6378 }
6379 }
6385 /* When making a call to a constructor or destructor for a subobject
6386 that uses virtual base classes, pass down a pointer to a VTT for
6387 the subobject. */
6391 {
6392 tree vtt;
6393 tree sub_vtt;
6395 /* If the current function is a complete object constructor
6396 or destructor, then we fetch the VTT directly.
6397 Otherwise, we look it up using the VTT we were given. */
6403 current_vtt_parm,
6404 vtt);
6410 {
6413 }
6416 }
6421 complain);
6427 }
6429 /* Return the NAME, as a C string. The NAME indicates a function that
6430 is a member of TYPE. *FREE_P is set to true if the caller must
6431 free the memory returned.
6433 Rather than go through all of this, we should simply set the names
6434 of constructors and destructors appropriately, and dispense with
6435 ctor_identifier, dtor_identifier, etc. */
6439 {
6442 /* Assume that we will not allocate memory. */
6444 /* Constructors and destructors are special. */
6446 {
6447 pretty_name
6449 /* For a destructor, add the '~'. */
6453 {
6455 /* Remember that we need to free the memory allocated. */
6457 }
6458 }
6460 {
6463 TFF_PLAIN_IDENTIFIER),
6464 NULL);
6465 /* Remember that we need to free the memory allocated. */
6467 }
6468 else
6472 }
6474 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
6475 be set, upon return, to the function called. ARGS may be NULL.
6476 This may change ARGS. */
6478 tree
6482 {
6486 tree access_binfo;
6487 tree optype;
6489 tree instance_ptr;
6490 tree name;
6493 tree call;
6494 tree fn;
6497 tree orig_instance;
6498 tree orig_fns;
6504 /* We don't know what function we're going to call, yet. */
6513 {
6517 }
6522 /* Dismantle the baselink to collect all the information we need. */
6529 {
6533 }
6544 {
6549 }
6552 /* Under DR 147 A::A() is an invalid constructor call,
6553 not a functional cast. */
6555 {
6565 complain);
6567 }
6569 /* Figure out whether to skip the first argument for the error
6570 message we will display to users if an error occurs. We don't
6571 want to display any compiler-generated arguments. The "this"
6572 pointer hasn't been added yet. However, we must remove the VTT
6573 pointer if this is a call to a base-class constructor or
6574 destructor. */
6577 {
6578 /* Callers should explicitly indicate whether they want to construct
6579 the complete object or just the part without virtual bases. */
6581 /* Similarly for destructors. */
6583 /* Remove the VTT pointer, if present. */
6587 }
6589 /* Process the argument list. */
6591 {
6595 }
6599 /* It's OK to call destructors and constructors on cv-qualified objects.
6600 Therefore, convert the INSTANCE_PTR to the unqualified type, if
6601 necessary. */
6604 {
6608 }
6614 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6617 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
6618 initializer, not T({ }). */
6622 {
6629 }
6630 else
6631 {
6635 }
6640 {
6642 {
6649 else
6650 {
6653 tree arglist;
6664 }
6666 }
6668 }
6669 else
6670 {
6673 {
6676 tree arglist;
6679 {
6685 arglist);
6689 }
6691 }
6692 else
6693 {
6702 /* This is not an error, it is runtime undefined
6703 behavior. */
6705 "pure virtual %q#D called from constructor"
6707 fn);
6711 {
6714 fn);
6716 }
6717 else
6718 {
6722 /* Now we know what function is being called. */
6725 /* Build the actual CALL_EXPR. */
6727 /* In an expression of the form `a->f()' where `f' turns
6728 out to be a static member function, `a' is
6729 none-the-less evaluated. */
6738 /* An explicit call of the form "x->~X()" has type
6739 "void". However, on platforms where destructors
6740 return "this" (i.e., those where
6741 targetm.cxx.cdtor_returns_this is true), such calls
6742 will appear to have a return value of pointer type
6743 to the low-level call machinery. We do not want to
6744 change the low-level machinery, since we want to be
6745 able to optimize "delete f()" on such platforms as
6746 "operator delete(~X(f()))" (rather than generating
6747 "t = f(), ~X(t), operator delete (t)"). */
6749 }
6750 }
6751 }
6754 {
6760 {
6763 }
6766 call = (build_min_non_dep_call_vec
6770 orig_args));
6774 }
6776 /* Free all the conversions we allocated. */
6783 }
6785 /* Returns true iff standard conversion sequence ICS1 is a proper
6786 subsequence of ICS2. */
6788 static bool
6790 {
6791 /* We can assume that a conversion of the same code
6792 between the same types indicates a subsequence since we only get
6793 here if the types we are converting from are the same. */
6800 {
6810 /* At this point, ICS1 cannot be a proper subsequence of
6811 ICS2. We can get a USER_CONV when we are comparing the
6812 second standard conversion sequence of two user conversion
6813 sequences. */
6823 }
6824 }
6826 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
6827 be any _TYPE nodes. */
6829 bool
6831 {
6835 /* We only allow proper derivation here. The DERIVED_FROM_P macro
6836 considers every class derived from itself. */
6839 }
6841 /* We build the ICS for an implicit object parameter as a pointer
6842 conversion sequence. However, such a sequence should be compared
6843 as if it were a reference conversion sequence. If ICS is the
6844 implicit conversion sequence for an implicit object parameter,
6845 modify it accordingly. */
6847 static void
6849 {
6851 {
6852 /* [over.match.funcs]
6854 For non-static member functions, the type of the
6855 implicit object parameter is "reference to cv X"
6856 where X is the class of which the function is a
6857 member and cv is the cv-qualification on the member
6858 function declaration. */
6860 tree reference_type;
6862 /* The `this' parameter is a pointer to a class type. Make the
6863 implicit conversion talk about a reference to that same class
6864 type. */
6877 }
6878 }
6880 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
6881 and return the initial reference binding conversion. Otherwise,
6882 leave *ICS unchanged and return NULL. */
6886 {
6888 {
6893 }
6896 }
6898 /* Compare two implicit conversion sequences according to the rules set out in
6899 [over.ics.rank]. Return values:
6901 1: ics1 is better than ics2
6902 -1: ics2 is better than ics1
6903 0: ics1 and ics2 are indistinguishable */
6905 static int
6907 {
6908 tree from_type1;
6909 tree from_type2;
6910 tree to_type1;
6911 tree to_type2;
6918 /* REF_BINDING is nonzero if the result of the conversion sequence
6919 is a reference type. In that case REF_CONV is the reference
6920 binding conversion. */
6924 /* Handle implicit object parameters. */
6928 /* Handle reference parameters. */
6932 /* List-initialization sequence L1 is a better conversion sequence than
6933 list-initialization sequence L2 if L1 converts to
6934 std::initializer_list<X> for some X and L2 does not. */
6940 /* [over.ics.rank]
6942 When comparing the basic forms of implicit conversion sequences (as
6943 defined in _over.best.ics_)
6945 --a standard conversion sequence (_over.ics.scs_) is a better
6946 conversion sequence than a user-defined conversion sequence
6947 or an ellipsis conversion sequence, and
6949 --a user-defined conversion sequence (_over.ics.user_) is a
6950 better conversion sequence than an ellipsis conversion sequence
6951 (_over.ics.ellipsis_). */
6961 {
6962 /* Both ICS are bad. We try to make a decision based on what would
6963 have happened if they'd been good. This is not an extension,
6964 we'll still give an error when we build up the call; this just
6965 helps us give a more helpful error message. */
6974 /* We couldn't make up our minds; try to figure it out below. */
6975 }
6978 /* Both conversions are ellipsis conversions. */
6981 /* User-defined conversion sequence U1 is a better conversion sequence
6982 than another user-defined conversion sequence U2 if they contain the
6983 same user-defined conversion operator or constructor and if the sec-
6984 ond standard conversion sequence of U1 is better than the second
6985 standard conversion sequence of U2. */
6987 /* Handle list-conversion with the same code even though it isn't always
6988 ranked as a user-defined conversion and it doesn't have a second
6989 standard conversion sequence; it will still have the desired effect.
6990 Specifically, we need to do the reference binding comparison at the
6991 end of this function. */
6994 {
7010 {
7013 }
7014 else
7015 {
7016 /* For ambiguous or aggregate conversions, use the target type as
7017 a proxy for the conversion function. */
7020 }
7022 /* We can just fall through here, after setting up
7023 FROM_TYPE1 and FROM_TYPE2. */
7026 }
7027 else
7028 {
7032 /* We're dealing with two standard conversion sequences.
7034 [over.ics.rank]
7036 Standard conversion sequence S1 is a better conversion
7037 sequence than standard conversion sequence S2 if
7039 --S1 is a proper subsequence of S2 (comparing the conversion
7040 sequences in the canonical form defined by _over.ics.scs_,
7041 excluding any Lvalue Transformation; the identity
7042 conversion sequence is considered to be a subsequence of
7043 any non-identity conversion sequence */
7054 }
7056 /* One sequence can only be a subsequence of the other if they start with
7057 the same type. They can start with different types when comparing the
7058 second standard conversion sequence in two user-defined conversion
7059 sequences. */
7061 {
7066 }
7068 /* [over.ics.rank]
7070 Or, if not that,
7072 --the rank of S1 is better than the rank of S2 (by the rules
7073 defined below):
7075 Standard conversion sequences are ordered by their ranks: an Exact
7076 Match is a better conversion than a Promotion, which is a better
7077 conversion than a Conversion.
7079 Two conversion sequences with the same rank are indistinguishable
7080 unless one of the following rules applies:
7082 --A conversion that does not a convert a pointer, pointer to member,
7083 or std::nullptr_t to bool is better than one that does.
7085 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
7086 so that we do not have to check it explicitly. */
7095 /* A conversion from scalar arithmetic type to complex is worse than a
7096 conversion between scalar arithmetic types. */
7103 {
7106 else
7108 }
7114 {
7119 }
7120 /* The rules for pointers to members A::* are just like the rules
7121 for pointers A*, except opposite: if B is derived from A then
7122 A::* converts to B::*, not vice versa. For that reason, we
7123 switch the from_ and to_ variables here. */
7130 {
7135 }
7140 {
7141 /* This was one of the pointer or pointer-like conversions.
7143 [over.ics.rank]
7145 --If class B is derived directly or indirectly from class A,
7146 conversion of B* to A* is better than conversion of B* to
7147 void*, and conversion of A* to void* is better than
7148 conversion of B* to void*. */
7151 {
7153 deref_from_type2))
7156 deref_from_type1))
7158 }
7161 {
7163 {
7165 {
7167 deref_to_type1))
7169 }
7170 /* We know that DEREF_TO_TYPE1 is `void' here. */
7172 deref_to_type2))
7174 }
7175 }
7178 {
7179 /* [over.ics.rank]
7181 --If class B is derived directly or indirectly from class A
7182 and class C is derived directly or indirectly from B,
7184 --conversion of C* to B* is better than conversion of C* to
7185 A*,
7187 --conversion of B* to A* is better than conversion of C* to
7188 A* */
7190 {
7192 deref_to_type2))
7195 deref_to_type1))
7197 }
7199 {
7201 deref_from_type1))
7204 deref_from_type2))
7206 }
7207 }
7208 }
7211 {
7214 /* [over.ics.rank]
7216 --binding of an expression of type C to a reference of type
7217 B& is better than binding an expression of type C to a
7218 reference of type A&
7220 --conversion of C to B is better than conversion of C to A, */
7223 {
7228 }
7229 }
7232 {
7235 /* [over.ics.rank]
7237 --binding of an expression of type B to a reference of type
7238 A& is better than binding an expression of type C to a
7239 reference of type A&,
7241 --conversion of B to A is better than conversion of C to A */
7244 {
7249 }
7250 }
7252 /* [over.ics.rank]
7254 --S1 and S2 differ only in their qualification conversion and yield
7255 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
7256 qualification signature of type T1 is a proper subset of the cv-
7257 qualification signature of type T2 */
7261 {
7265 }
7267 /* [over.ics.rank]
7269 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
7270 to an implicit object parameter, and either S1 binds an lvalue reference
7271 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
7272 reference to an rvalue and S2 binds an lvalue reference
7273 (C++0x draft standard, 13.3.3.2)
7275 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
7276 types to which the references refer are the same type except for
7277 top-level cv-qualifiers, and the type to which the reference
7278 initialized by S2 refers is more cv-qualified than the type to
7279 which the reference initialized by S1 refers */
7282 {
7286 {
7291 }
7296 }
7298 /* Neither conversion sequence is better than the other. */
7300 }
7302 /* The source type for this standard conversion sequence. */
7304 static tree
7306 {
7308 {
7313 }
7315 }
7317 /* Note a warning about preferring WINNER to LOSER. We do this by storing
7318 a pointer to LOSER and re-running joust to produce the warning if WINNER
7319 is actually used. */
7321 static void
7323 {
7329 }
7331 /* Compare two candidates for overloading as described in
7332 [over.match.best]. Return values:
7334 1: cand1 is better than cand2
7335 -1: cand2 is better than cand1
7336 0: cand1 and cand2 are indistinguishable */
7338 static int
7340 {
7346 /* Candidates that involve bad conversions are always worse than those
7347 that don't. */
7353 /* If we have two pseudo-candidates for conversions to the same type,
7354 or two candidates for the same function, arbitrarily pick one. */
7359 /* a viable function F1
7360 is defined to be a better function than another viable function F2 if
7361 for all arguments i, ICSi(F1) is not a worse conversion sequence than
7362 ICSi(F2), and then */
7364 /* for some argument j, ICSj(F1) is a better conversion sequence than
7365 ICSj(F2) */
7367 /* For comparing static and non-static member functions, we ignore
7368 the implicit object parameter of the non-static function. The
7369 standard says to pretend that the static function has an object
7370 parm, but that won't work with operator overloading. */
7373 {
7381 else
7382 {
7385 }
7386 }
7389 {
7395 {
7408 {
7415 else
7420 {
7424 }
7425 else
7427 }
7430 {
7433 }
7435 }
7436 }
7438 /* warn about confusing overload resolution for user-defined conversions,
7439 either between a constructor and a conversion op, or between two
7440 conversion ops. */
7444 {
7450 else
7453 /* We don't want to complain about `X::operator T1 ()'
7454 beating `X::operator T2 () const', when T2 is a no less
7455 cv-qualified version of T1. */
7458 {
7463 {
7466 }
7469 }
7470 else
7476 {
7483 {
7485 }
7486 }
7487 else
7489 }
7494 /* or, if not that,
7495 F1 is a non-template function and F2 is a template function
7496 specialization. */
7503 /* or, if not that,
7504 F1 and F2 are template functions and the function template for F1 is
7505 more specialized than the template for F2 according to the partial
7506 ordering rules. */
7509 {
7510 winner = more_specialized_fn
7513 /* [temp.func.order]: The presence of unused ellipsis and default
7514 arguments has no effect on the partial ordering of function
7515 templates. add_function_candidate() will not have
7516 counted the "this" argument for constructors. */
7520 }
7522 /* or, if not that,
7523 the context is an initialization by user-defined conversion (see
7524 _dcl.init_ and _over.match.user_) and the standard conversion
7525 sequence from the return type of F1 to the destination type (i.e.,
7526 the type of the entity being initialized) is a better conversion
7527 sequence than the standard conversion sequence from the return type
7528 of F2 to the destination type. */
7531 {
7535 }
7537 /* Check whether we can discard a builtin candidate, either because we
7538 have two identical ones or matching builtin and non-builtin candidates.
7540 (Pedantically in the latter case the builtin which matched the user
7541 function should not be added to the overload set, but we spot it here.
7543 [over.match.oper]
7544 ... the builtin candidates include ...
7545 - do not have the same parameter type list as any non-template
7546 non-member candidate. */
7550 {
7556 {
7558 /* Two built-in candidates; arbitrarily pick one. */
7561 /* cand1 is built-in; prefer cand2. */
7563 else
7564 /* cand2 is built-in; prefer cand1. */
7566 }
7567 }
7569 /* If the two function declarations represent the same function (this can
7570 happen with declarations in multiple scopes and arg-dependent lookup),
7571 arbitrarily choose one. But first make sure the default args we're
7572 using match. */
7575 {
7582 {
7583 /* Don't crash if the fn is variadic. */
7588 }
7596 {
7599 {
7601 {
7608 }
7609 else
7612 }
7615 }
7618 }
7620 tweak:
7622 /* Extension: If the worst conversion for one candidate is worse than the
7623 worst conversion for the other, take the first. */
7625 {
7630 {
7635 }
7641 {
7642 /* Don't choose a deleted function over ambiguity. */
7646 {
7648 "ISO C++ says that these are ambiguous, even "
7649 "though the worst conversion for the first is better than "
7653 }
7654 else
7657 }
7658 }
7662 }
7664 /* Given a list of candidates for overloading, find the best one, if any.
7665 This algorithm has a worst case of O(2n) (winner is last), and a best
7666 case of O(n/2) (totally ambiguous); much better than a sorting
7667 algorithm. */
7671 {
7676 /* Walk through the list once, comparing each current champ to the next
7677 candidate, knocking out a candidate or two with each comparison. */
7680 {
7684 else
7685 {
7687 {
7692 }
7693 else
7694 {
7697 }
7700 }
7701 }
7703 /* Make sure the champ is better than all the candidates it hasn't yet
7704 been compared to. */
7707 challenger != champ
7710 {
7714 }
7717 }
7719 /* Returns nonzero if things of type FROM can be converted to TO. */
7721 bool
7723 {
7725 }
7727 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
7729 bool
7731 {
7736 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7740 flags);
7743 /* Free all the conversions we allocated. */
7747 }
7749 /* Like can_convert_arg, but allows dubious conversions as well. */
7751 bool
7753 {
7757 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7759 /* Try to perform the conversion. */
7761 flags);
7762 /* Free all the conversions we allocated. */
7766 }
7768 /* Convert EXPR to TYPE. Return the converted expression.
7770 Note that we allow bad conversions here because by the time we get to
7771 this point we are committed to doing the conversion. If we end up
7772 doing a bad conversion, convert_like will complain. */
7774 tree
7776 {
7783 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7788 flags);
7791 {
7793 {
7794 /* If expr has unknown type, then it is an overloaded function.
7795 Call instantiate_type to get good error messages. */
7800 else
7802 }
7804 }
7806 {
7807 /* In a template, we are only concerned about determining the
7808 type of non-dependent expressions, so we do not have to
7809 perform the actual conversion. */
7812 }
7813 else
7816 /* Free all the conversions we allocated. */
7820 }
7822 tree
7824 {
7826 }
7828 /* Convert EXPR to TYPE (as a direct-initialization) if that is
7829 permitted. If the conversion is valid, the converted expression is
7830 returned. Otherwise, NULL_TREE is returned, except in the case
7831 that TYPE is a class type; in that case, an error is issued. If
7832 C_CAST_P is true, then this direction initialization is taking
7833 place as part of a static_cast being attempted as part of a C-style
7834 cast. */
7836 tree
7838 tree expr,
7840 tsubst_flags_t complain)
7841 {
7847 /* [dcl.init]
7849 If the destination type is a (possibly cv-qualified) class type:
7851 -- If the initialization is direct-initialization ...,
7852 constructors are considered. ... If no constructor applies, or
7853 the overload resolution is ambiguous, the initialization is
7854 ill-formed. */
7856 {
7862 }
7864 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7868 c_cast_p,
7869 LOOKUP_NORMAL);
7872 else
7875 c_cast_p,
7876 complain);
7878 /* Free all the conversions we allocated. */
7882 }
7884 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
7885 is being bound to a temporary. Create and return a new VAR_DECL
7886 with the indicated TYPE; this variable will store the value to
7887 which the reference is bound. */
7889 tree
7891 {
7892 tree var;
7894 /* Create the variable. */
7897 /* Register the variable. */
7899 {
7900 /* Namespace-scope or local static; give it a mangled name. */
7901 tree name;
7908 }
7909 else
7910 /* Create a new cleanup level if necessary. */
7914 }
7916 /* EXPR is the initializer for a variable DECL of reference or
7917 std::initializer_list type. Create, push and return a new VAR_DECL
7918 for the initializer so that it will live as long as DECL. Any
7919 cleanup for the new variable is returned through CLEANUP, and the
7920 code to initialize the new variable is returned through INITP. */
7922 tree
7924 {
7925 tree init;
7926 tree type;
7927 tree var;
7929 /* Create the temporary variable. */
7933 /* If the rvalue is the result of a function call it will be
7934 a TARGET_EXPR. If it is some other construct (such as a
7935 member access expression where the underlying object is
7936 itself the result of a function call), turn it into a
7937 TARGET_EXPR here. It is important that EXPR be a
7938 TARGET_EXPR below since otherwise the INIT_EXPR will
7939 attempt to make a bitwise copy of EXPR to initialize
7940 VAR. */
7944 /* If the initializer is constant, put it in DECL_INITIAL so we get
7945 static initialization and use in constant expressions. */
7948 {
7950 {
7951 /* 5.19 says that a constant expression can include an
7952 lvalue-rvalue conversion applied to "a glvalue of literal type
7953 that refers to a non-volatile temporary object initialized
7954 with a constant expression". Rather than try to communicate
7955 that this VAR_DECL is a temporary, just mark it constexpr.
7957 Currently this is only useful for initializer_list temporaries,
7958 since reference vars can't appear in constant expressions. */
7961 }
7964 }
7965 else
7966 /* Create the INIT_EXPR that will initialize the temporary
7967 variable. */
7970 {
7975 else
7978 /* We must be careful to destroy the temporary only
7979 after its initialization has taken place. If the
7980 initialization throws an exception, then the
7981 destructor should not be run. We cannot simply
7982 transform INIT into something like:
7984 (INIT, ({ CLEANUP_STMT; }))
7986 because emit_local_var always treats the
7987 initializer as a full-expression. Thus, the
7988 destructor would run too early; it would run at the
7989 end of initializing the reference variable, rather
7990 than at the end of the block enclosing the
7991 reference variable.
7993 The solution is to pass back a cleanup expression
7994 which the caller is responsible for attaching to
7995 the statement tree. */
7996 }
7997 else
7998 {
8002 static_aggregates);
8003 }
8007 }
8009 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
8010 initializing a variable of that TYPE. If DECL is non-NULL, it is
8011 the VAR_DECL being initialized with the EXPR. (In that case, the
8012 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
8013 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
8014 return, if *CLEANUP is no longer NULL, it will be an expression
8015 that should be pushed as a cleanup after the returned expression
8016 is used to initialize DECL.
8018 Return the converted expression. */
8020 tree
8022 tsubst_flags_t complain)
8023 {
8030 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8034 LOOKUP_NORMAL);
8036 {
8038 {
8045 else
8049 }
8051 }
8053 /* If DECL is non-NULL, then this special rule applies:
8055 [class.temporary]
8057 The temporary to which the reference is bound or the temporary
8058 that is the complete object to which the reference is bound
8059 persists for the lifetime of the reference.
8061 The temporaries created during the evaluation of the expression
8062 initializing the reference, except the temporary to which the
8063 reference is bound, are destroyed at the end of the
8064 full-expression in which they are created.
8066 In that case, we store the converted expression into a new
8067 VAR_DECL in a new scope.
8069 However, we want to be careful not to create temporaries when
8070 they are not required. For example, given:
8072 struct B {};
8073 struct D : public B {};
8074 D f();
8075 const B& b = f();
8077 there is no need to copy the return value from "f"; we can just
8078 extend its lifetime. Similarly, given:
8080 struct S {};
8081 struct T { operator S(); };
8082 T t;
8083 const S& s = t;
8085 we can extend the lifetime of the return value of the conversion
8086 operator. */
8089 {
8090 tree var;
8091 tree base_conv_type;
8093 /* Skip over the REF_BIND. */
8095 /* If the next conversion is a BASE_CONV, skip that too -- but
8096 remember that the conversion was required. */
8098 {
8101 }
8102 else
8104 /* Perform the remainder of the conversion. */
8110 tf_warning_or_error);
8113 else
8114 {
8116 {
8117 tree init;
8119 /* Use its address to initialize the reference variable. */
8128 }
8129 else
8130 /* Take the address of EXPR. */
8132 /* If a BASE_CONV was required, perform it now. */
8134 expr = (perform_implicit_conversion
8136 tf_warning_or_error));
8138 }
8139 }
8140 else
8141 /* Perform the conversion. */
8144 /* Free all the conversions we allocated. */
8148 }
8150 /* Returns true iff TYPE is some variant of std::initializer_list. */
8152 bool
8154 {
8155 /* Look through typedefs. */
8162 }
8164 /* Returns true iff DECL is a list constructor: i.e. a constructor which
8165 will accept an argument list of a single std::initializer_list<T>. */
8167 bool
8169 {
8171 tree arg;
8183 /* There are more non-defaulted parms. */
8187 }