| blob | 0bf7b8eb58d7b152e6abb97c25bbe217baa82ce6 |
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. */
474 {
478 }
480 }
482 /* Returns nonzero if PARMLIST consists of only default parms and/or
483 ellipsis. */
485 bool
487 {
493 }
495 /* Allocate N bytes of memory from the conversion obstack. The memory
496 is zeroed before being returned. */
500 {
503 {
506 }
510 }
512 /* Dynamically allocate a conversion. */
516 {
521 }
523 #ifdef ENABLE_CHECKING
525 /* Make sure that all memory on the conversion obstack has been
526 freed. */
528 void
530 {
534 }
538 /* Dynamically allocate an array of N conversions. */
542 {
544 }
548 {
552 /* Note that the caller is responsible for filling in t->cand for
553 user-defined conversions. */
559 {
575 }
581 }
583 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
584 specialization of std::initializer_list<T>, if such a conversion is
585 possible. */
589 {
595 tree val;
597 /* Within a list-initialization we can have more user-defined
598 conversions. */
600 /* But no narrowing conversions. */
604 {
605 conversion *sub
612 }
620 {
628 }
631 }
633 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
634 aggregate class, if such a conversion is possible. */
638 {
645 {
647 {
655 }
656 else
657 {
663 }
664 }
675 }
677 /* Build a representation of the identity conversion from EXPR to
678 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
682 {
690 }
692 /* Converting from EXPR to TYPE was ambiguous in the sense that there
693 were multiple user-defined conversions to accomplish the job.
694 Build a conversion that indicates that ambiguity. */
698 {
706 }
708 tree
710 {
714 }
716 /* Returns the standard conversion path (see [conv]) from type FROM to type
717 TO, if any. For proper handling of null pointer constants, you must
718 also pass the expression EXPR to convert from. If C_CAST_P is true,
719 this conversion is coming from a C-style cast. */
724 {
731 {
734 }
740 {
748 }
755 {
759 }
761 {
763 {
764 tree bitfield_type;
767 {
770 }
771 }
773 }
775 /* Allow conversion between `__complex__' data types. */
777 {
778 /* The standard conversion sequence to convert FROM to TO is
779 the standard conversion sequence to perform componentwise
780 conversion. */
785 {
788 }
789 else
793 }
798 /* [conv.ptr]
799 A null pointer constant can be converted to a pointer type; ... A
800 null pointer constant of integral type can be converted to an
801 rvalue of type std::nullptr_t. */
808 {
809 /* For backwards brain damage compatibility, allow interconversion of
810 pointers and integers with a pedwarn. */
813 }
815 {
816 /* For backwards brain damage compatibility, allow interconversion of
817 enums and integers with a pedwarn. */
820 }
823 {
824 tree to_pointee;
825 tree from_pointee;
830 ;
834 {
835 from = build_pointer_type
839 }
841 {
846 && (same_type_ignoring_top_level_qualifiers_p
849 {
853 }
856 }
859 /* [conv.ptr]
861 An rvalue of type "pointer to cv D," where D is a
862 class type, can be converted to an rvalue of type
863 "pointer to cv B," where B is a base class (clause
864 _class.derived_) of D. If B is an inaccessible
865 (clause _class.access_) or ambiguous
866 (_class.member.lookup_) base class of D, a program
867 that necessitates this conversion is ill-formed.
868 Therefore, we use DERIVED_FROM_P, and do not check
869 access or uniqueness. */
871 {
872 from =
878 }
881 {
884 }
885 else
886 {
889 }
894 /* In a C-style cast, we ignore CV-qualification because we
895 are allowed to perform a static_cast followed by a
896 const_cast. */
901 /* converting from string constant to char *. */
904 {
907 }
908 else
912 }
914 {
931 }
933 {
934 /* [conv.bool]
936 An rvalue of arithmetic, unscoped enumeration, pointer, or
937 pointer to member type can be converted to an rvalue of type
938 bool. ... An rvalue of type std::nullptr_t can be converted
939 to an rvalue of type bool; */
945 {
954 }
957 }
958 /* We don't check for ENUMERAL_TYPE here because there are no standard
959 conversions to enum type. */
960 /* As an extension, allow conversion to complex type. */
962 {
968 /* Give this a better rank if it's a promotion. */
972 }
978 {
982 /* The derived-to-base conversion indicates the initialization
983 of a parameter with base type from an object of a derived
984 type. A temporary object is created to hold the result of
985 the conversion unless we're binding directly to a reference. */
987 }
988 else
995 }
997 /* Returns nonzero if T1 is reference-related to T2. */
999 bool
1001 {
1005 /* [dcl.init.ref]
1007 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1008 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1009 of T2. */
1013 }
1015 /* Returns nonzero if T1 is reference-compatible with T2. */
1017 static bool
1019 {
1020 /* [dcl.init.ref]
1022 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1023 reference-related to T2 and cv1 is the same cv-qualification as,
1024 or greater cv-qualification than, cv2. */
1027 }
1029 /* Determine whether or not the EXPR (of class type S) can be
1030 converted to T as in [over.match.ref]. */
1034 {
1035 tree conversions;
1036 tree first_arg;
1038 tree t;
1050 /* [over.match.ref]
1052 Assuming that "cv1 T" is the underlying type of the reference
1053 being initialized, and "cv S" is the type of the initializer
1054 expression, with S a class type, the candidate functions are
1055 selected as follows:
1057 --The conversion functions of S and its base classes are
1058 considered. Those that are not hidden within S and yield type
1059 "reference to cv2 T2", where "cv1 T" is reference-compatible
1060 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
1062 The argument list has one argument, which is the initializer
1063 expression. */
1067 /* Conceptually, we should take the address of EXPR and put it in
1068 the argument list. Unfortunately, however, that can result in
1069 error messages, which we should not issue now because we are just
1070 trying to find a conversion operator. Therefore, we use NULL,
1071 cast to the appropriate type. */
1076 /* We're performing a user-defined conversion to a desired type, so set
1077 this for the benefit of add_candidates. */
1081 {
1092 {
1093 /* Now, see if the conversion function really returns
1094 an lvalue of the appropriate type. From the
1095 point of view of unification, simply returning an
1096 rvalue of the right type is good enough. */
1101 {
1103 }
1104 else
1105 {
1107 /* Build a standard conversion sequence indicating the
1108 binding from the reference type returned by the
1109 function to the desired REFERENCE_TYPE. */
1110 identity_conv
1113 NULL_TREE);
1114 cand->second_conv
1115 = (direct_reference_binding
1122 /* Don't allow binding of lvalues to rvalue references. */
1126 }
1127 }
1128 }
1131 /* If none of the conversion functions worked out, let our caller
1132 know. */
1140 /* Now that we know that this is the function we're going to use fix
1141 the dummy first argument. */
1146 /* Build a user-defined conversion sequence representing the
1147 conversion. */
1156 /* Merge it with the standard conversion sequence from the
1157 conversion function's return type to the desired type. */
1161 }
1163 /* A reference of the indicated TYPE is being bound directly to the
1164 expression represented by the implicit conversion sequence CONV.
1165 Return a conversion sequence for this binding. */
1169 {
1170 tree t;
1177 /* [over.ics.rank]
1179 When a parameter of reference type binds directly
1180 (_dcl.init.ref_) to an argument expression, the implicit
1181 conversion sequence is the identity conversion, unless the
1182 argument expression has a type that is a derived class of the
1183 parameter type, in which case the implicit conversion sequence is
1184 a derived-to-base Conversion.
1186 If the parameter binds directly to the result of applying a
1187 conversion function to the argument expression, the implicit
1188 conversion sequence is a user-defined conversion sequence
1189 (_over.ics.user_), with the second standard conversion sequence
1190 either an identity conversion or, if the conversion function
1191 returns an entity of a type that is a derived class of the
1192 parameter type, a derived-to-base conversion. */
1194 {
1195 /* Represent the derived-to-base conversion. */
1197 /* We will actually be binding to the base-class subobject in
1198 the derived class, so we mark this conversion appropriately.
1199 That way, convert_like knows not to generate a temporary. */
1201 }
1203 }
1205 /* Returns the conversion path from type FROM to reference type TO for
1206 purposes of reference binding. For lvalue binding, either pass a
1207 reference type to FROM or an lvalue expression to EXPR. If the
1208 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1209 the conversion returned. If C_CAST_P is true, this
1210 conversion is coming from a C-style cast. */
1214 {
1218 tree tfrom;
1224 {
1229 }
1232 {
1233 /* Anything with reference type is an lvalue. */
1236 }
1239 {
1242 flags);
1245 {
1250 }
1251 }
1260 /* Figure out whether or not the types are reference-related and
1261 reference compatible. We have do do this after stripping
1262 references from FROM. */
1264 /* If this is a C cast, first convert to an appropriately qualified
1265 type, so that we can later do a const_cast to the desired type. */
1271 /* Directly bind reference when target expression's type is compatible with
1272 the reference and expression is an lvalue. In DR391, the wording in
1273 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1274 const and rvalue references to rvalues of compatible class type.
1275 We should also do direct bindings for non-class "rvalues" derived from
1276 rvalue references. */
1278 && (is_lvalue
1283 {
1284 /* [dcl.init.ref]
1286 If the initializer expression
1288 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1289 is reference-compatible with "cv2 T2,"
1291 the reference is bound directly to the initializer expression
1292 lvalue.
1294 [...]
1295 If the initializer expression is an rvalue, with T2 a class type,
1296 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1297 is bound to the object represented by the rvalue or to a sub-object
1298 within that object. */
1304 /* The top-level caller requested that we pretend that the lvalue
1305 be treated as an rvalue. */
1307 else
1308 conv->rvaluedness_matches_p
1313 /* For the purposes of overload resolution, we ignore the fact
1314 this expression is a bitfield or packed field. (In particular,
1315 [over.ics.ref] says specifically that a function with a
1316 non-const reference parameter is viable even if the
1317 argument is a bitfield.)
1319 However, when we actually call the function we must create
1320 a temporary to which to bind the reference. If the
1321 reference is volatile, or isn't const, then we cannot make
1322 a temporary, so we just issue an error when the conversion
1323 actually occurs. */
1326 /* Don't allow binding of lvalues to rvalue references. */
1332 }
1333 /* [class.conv.fct] A conversion function is never used to convert a
1334 (possibly cv-qualified) object to the (possibly cv-qualified) same
1335 object type (or a reference to it), to a (possibly cv-qualified) base
1336 class of that type (or a reference to it).... */
1339 {
1340 /* [dcl.init.ref]
1342 If the initializer expression
1344 -- has a class type (i.e., T2 is a class type) can be
1345 implicitly converted to an lvalue of type "cv3 T3," where
1346 "cv1 T1" is reference-compatible with "cv3 T3". (this
1347 conversion is selected by enumerating the applicable
1348 conversion functions (_over.match.ref_) and choosing the
1349 best one through overload resolution. (_over.match_).
1351 the reference is bound to the lvalue result of the conversion
1352 in the second case. */
1356 }
1358 /* From this point on, we conceptually need temporaries, even if we
1359 elide them. Only the cases above are "direct bindings". */
1363 /* [over.ics.rank]
1365 When a parameter of reference type is not bound directly to an
1366 argument expression, the conversion sequence is the one required
1367 to convert the argument expression to the underlying type of the
1368 reference according to _over.best.ics_. Conceptually, this
1369 conversion sequence corresponds to copy-initializing a temporary
1370 of the underlying type with the argument expression. Any
1371 difference in top-level cv-qualification is subsumed by the
1372 initialization itself and does not constitute a conversion. */
1374 /* [dcl.init.ref]
1376 Otherwise, the reference shall be to a non-volatile const type.
1378 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1382 /* [dcl.init.ref]
1384 Otherwise, a temporary of type "cv1 T1" is created and
1385 initialized from the initializer expression using the rules for a
1386 non-reference copy initialization. If T1 is reference-related to
1387 T2, cv1 must be the same cv-qualification as, or greater
1388 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1392 /* We're generating a temporary now, but don't bind any more in the
1393 conversion (specifically, don't slice the temporary returned by a
1394 conversion operator). */
1397 /* Core issue 899: When [copy-]initializing a temporary to be bound
1398 to the first parameter of a copy constructor (12.8) called with
1399 a single argument in the context of direct-initialization,
1400 explicit conversion functions are also considered.
1402 So don't set LOOKUP_ONLYCONVERTING in that case. */
1408 flags);
1413 /* This reference binding, unlike those above, requires the
1414 creation of a temporary. */
1419 }
1421 /* Returns the implicit conversion sequence (see [over.ics]) from type
1422 FROM to type TO. The optional expression EXPR may affect the
1423 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1424 true, this conversion is coming from a C-style cast. */
1429 {
1438 else
1445 {
1449 /* Allow conversion from an initializer-list with one element to a
1450 scalar type. */
1452 {
1454 tree elt;
1460 else
1466 {
1469 /* Too many levels of braces, i.e. '{{1}}'. */
1472 }
1473 }
1474 }
1480 {
1494 /* We used to try to bind a reference to a temporary here, but that
1495 is now handled after the recursive call to this function at the end
1496 of reference_binding. */
1498 }
1501 }
1503 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1504 functions. ARGS will not be changed until a single candidate is
1505 selected. */
1513 {
1529 }
1531 /* Create an overload candidate for the function or method FN called
1532 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1533 FLAGS is passed on to implicit_conversion.
1535 This does not change ARGS.
1537 CTYPE, if non-NULL, is the type we want to pretend this function
1538 comes from for purposes of overload resolution. */
1545 {
1549 tree parmnode;
1554 /* At this point we should not see any functions which haven't been
1555 explicitly declared, except for friend functions which will have
1556 been found using argument dependent lookup. */
1559 /* The `this', `in_chrg' and VTT arguments to constructors are not
1560 considered in overload resolution. */
1562 {
1566 {
1569 }
1570 }
1571 else
1577 /* 13.3.2 - Viable functions [over.match.viable]
1578 First, to be a viable function, a candidate function shall have enough
1579 parameters to agree in number with the arguments in the list.
1581 We need to check this first; otherwise, checking the ICSes might cause
1582 us to produce an ill-formed template instantiation. */
1586 {
1590 }
1595 /* Make sure there are default args for the rest of the parms. */
1602 /* Second, for F to be a viable function, there shall exist for each
1603 argument an implicit conversion sequence that converts that argument
1604 to the corresponding parameter of F. */
1609 {
1619 else
1628 {
1634 /* The type of the implicit object parameter ('this') for
1635 overload resolution is not always the same as for the
1636 function itself; conversion functions are considered to
1637 be members of the class being converted, and functions
1638 introduced by a using-declaration are considered to be
1639 members of the class that uses them.
1641 Since build_over_call ignores the ICS for the `this'
1642 parameter, we can just change the parm type. */
1644 {
1645 parmtype = cp_build_qualified_type
1648 }
1650 /* Core issue 899: When [copy-]initializing a temporary to be bound
1651 to the first parameter of a copy constructor (12.8) called with
1652 a single argument in the context of direct-initialization,
1653 explicit conversion functions are also considered.
1655 So set LOOKUP_COPY_PARM to let reference_binding know that
1656 it's being called in that context. We generalize the above
1657 to handle move constructors and template constructors as well;
1658 the standardese should soon be updated similarly. */
1663 && (same_type_ignoring_top_level_qualifiers_p
1665 {
1667 /* We allow user-defined conversions within init-lists, but
1668 not for the copy constructor. */
1671 }
1672 else
1677 }
1678 else
1679 {
1682 }
1689 {
1692 }
1696 }
1698 out:
1701 }
1703 /* Create an overload candidate for the conversion function FN which will
1704 be invoked for expression OBJ, producing a pointer-to-function which
1705 will in turn be called with the argument list FIRST_ARG/ARGLIST,
1706 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
1707 passed on to implicit_conversion.
1709 Actually, we don't really care about FN; we care about the type it
1710 converts to. There may be multiple conversion functions that will
1711 convert to that type, and we rely on build_user_type_conversion_1 to
1712 choose the best one; so when we create our candidate, we record the type
1713 instead of the function. */
1719 {
1735 /* Don't bother looking up the same type twice. */
1740 {
1748 else
1755 flags);
1761 else
1762 {
1765 }
1779 }
1789 }
1791 static void
1795 {
1808 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
1809 conversion ops are allowed. We handle that here by just checking for
1810 boolean_type_node because other operators don't ask for it. COND_EXPR
1811 also does contextual conversion to bool for the first operand, but we
1812 handle that in build_conditional_expr, and type1 here is operand 2. */
1817 {
1824 {
1826 /* We need something for printing the candidate. */
1828 }
1832 }
1834 /* For COND_EXPR we rearranged the arguments; undo that now. */
1836 {
1843 else
1845 }
1851 viable);
1852 }
1854 static bool
1856 {
1858 }
1860 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1862 static bool
1864 {
1865 /* [over.built]
1867 In this section, the term promoted integral type is used to refer
1868 to those integral types which are preserved by integral promotion
1869 (including e.g. int and long but excluding e.g. char).
1870 Similarly, the term promoted arithmetic type refers to promoted
1871 integral types plus floating types. */
1875 }
1877 /* Create any builtin operator overload candidates for the operator in
1878 question given the converted operand types TYPE1 and TYPE2. The other
1879 args are passed through from add_builtin_candidates to
1880 build_builtin_candidate.
1882 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1883 If CODE is requires candidates operands of the same type of the kind
1884 of which TYPE1 and TYPE2 are, we add both candidates
1885 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1887 static void
1891 {
1893 {
1901 }
1904 {
1906 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1907 and VQ is either volatile or empty, there exist candidate operator
1908 functions of the form
1909 VQ T& operator++(VQ T&);
1910 T operator++(VQ T&, int);
1911 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1912 type other than bool, and VQ is either volatile or empty, there exist
1913 candidate operator functions of the form
1914 VQ T& operator--(VQ T&);
1915 T operator--(VQ T&, int);
1916 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1917 complete object type, and VQ is either volatile or empty, there exist
1918 candidate operator functions of the form
1919 T*VQ& operator++(T*VQ&);
1920 T*VQ& operator--(T*VQ&);
1921 T* operator++(T*VQ&, int);
1922 T* operator--(T*VQ&, int); */
1931 {
1934 }
1937 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1938 exist candidate operator functions of the form
1940 T& operator*(T*);
1942 8 For every function type T, there exist candidate operator functions of
1943 the form
1944 T& operator*(T*); */
1953 /* 9 For every type T, there exist candidate operator functions of the form
1954 T* operator+(T*);
1956 10For every promoted arithmetic type T, there exist candidate operator
1957 functions of the form
1958 T operator+(T);
1959 T operator-(T); */
1969 /* 11For every promoted integral type T, there exist candidate operator
1970 functions of the form
1971 T operator~(T); */
1978 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1979 is the same type as C2 or is a derived class of C2, T is a complete
1980 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1981 there exist candidate operator functions of the form
1982 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1983 where CV12 is the union of CV1 and CV2. */
1988 {
1996 }
1999 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2000 didate operator functions of the form
2001 LR operator*(L, R);
2002 LR operator/(L, R);
2003 LR operator+(L, R);
2004 LR operator-(L, R);
2005 bool operator<(L, R);
2006 bool operator>(L, R);
2007 bool operator<=(L, R);
2008 bool operator>=(L, R);
2009 bool operator==(L, R);
2010 bool operator!=(L, R);
2011 where LR is the result of the usual arithmetic conversions between
2012 types L and R.
2014 14For every pair of types T and I, where T is a cv-qualified or cv-
2015 unqualified complete object type and I is a promoted integral type,
2016 there exist candidate operator functions of the form
2017 T* operator+(T*, I);
2018 T& operator[](T*, I);
2019 T* operator-(T*, I);
2020 T* operator+(I, T*);
2021 T& operator[](I, T*);
2023 15For every T, where T is a pointer to complete object type, there exist
2024 candidate operator functions of the form112)
2025 ptrdiff_t operator-(T, T);
2027 16For every pointer or enumeration type T, there exist candidate operator
2028 functions of the form
2029 bool operator<(T, T);
2030 bool operator>(T, T);
2031 bool operator<=(T, T);
2032 bool operator>=(T, T);
2033 bool operator==(T, T);
2034 bool operator!=(T, T);
2036 17For every pointer to member type T, there exist candidate operator
2037 functions of the form
2038 bool operator==(T, T);
2039 bool operator!=(T, T); */
2046 {
2049 }
2062 {
2065 }
2067 {
2070 }
2071 /* Fall through. */
2088 {
2091 }
2095 {
2098 }
2106 {
2109 }
2111 {
2114 }
2117 /* 18For every pair of promoted integral types L and R, there exist candi-
2118 date operator functions of the form
2119 LR operator%(L, R);
2120 LR operator&(L, R);
2121 LR operator^(L, R);
2122 LR operator|(L, R);
2123 L operator<<(L, R);
2124 L operator>>(L, R);
2125 where LR is the result of the usual arithmetic conversions between
2126 types L and R. */
2134 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2138 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2139 type, VQ is either volatile or empty, and R is a promoted arithmetic
2140 type, there exist candidate operator functions of the form
2141 VQ L& operator=(VQ L&, R);
2142 VQ L& operator*=(VQ L&, R);
2143 VQ L& operator/=(VQ L&, R);
2144 VQ L& operator+=(VQ L&, R);
2145 VQ L& operator-=(VQ L&, R);
2147 20For every pair T, VQ), where T is any type and VQ is either volatile
2148 or empty, there exist candidate operator functions of the form
2149 T*VQ& operator=(T*VQ&, T*);
2151 21For every pair T, VQ), where T is a pointer to member type and VQ is
2152 either volatile or empty, there exist candidate operator functions of
2153 the form
2154 VQ T& operator=(VQ T&, T);
2156 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2157 unqualified complete object type, VQ is either volatile or empty, and
2158 I is a promoted integral type, there exist candidate operator func-
2159 tions of the form
2160 T*VQ& operator+=(T*VQ&, I);
2161 T*VQ& operator-=(T*VQ&, I);
2163 23For every triple L, VQ, R), where L is an integral or enumeration
2164 type, VQ is either volatile or empty, and R is a promoted integral
2165 type, there exist candidate operator functions of the form
2167 VQ L& operator%=(VQ L&, R);
2168 VQ L& operator<<=(VQ L&, R);
2169 VQ L& operator>>=(VQ L&, R);
2170 VQ L& operator&=(VQ L&, R);
2171 VQ L& operator^=(VQ L&, R);
2172 VQ L& operator|=(VQ L&, R); */
2176 {
2180 {
2183 }
2196 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2209 {
2212 }
2217 }
2222 /* [over.built]
2224 For every pair of promoted arithmetic types L and R, there
2225 exist candidate operator functions of the form
2227 LR operator?(bool, L, R);
2229 where LR is the result of the usual arithmetic conversions
2230 between types L and R.
2232 For every type T, where T is a pointer or pointer-to-member
2233 type, there exist candidate operator functions of the form T
2234 operator?(bool, T, T); */
2238 /* That's OK. */
2241 /* Otherwise, the types should be pointers. */
2246 /* We don't check that the two types are the same; the logic
2247 below will actually create two candidates; one in which both
2248 parameter types are TYPE1, and one in which both parameter
2249 types are TYPE2. */
2254 }
2256 /* If we're dealing with two pointer types or two enumeral types,
2257 we need candidates for both of them. */
2266 {
2267 build_builtin_candidate
2269 build_builtin_candidate
2272 }
2274 build_builtin_candidate
2276 }
2278 tree
2280 {
2288 }
2290 /* There are three conditions of builtin candidates:
2292 1) bool-taking candidates. These are the same regardless of the input.
2293 2) pointer-pair taking candidates. These are generated for each type
2294 one of the input types converts to.
2295 3) arithmetic candidates. According to the standard, we should generate
2296 all of these, but I'm trying not to...
2298 Here we generate a superset of the possible candidates for this particular
2299 case. That is a subset of the full set the standard defines, plus some
2300 other cases which the standard disallows. add_builtin_candidate will
2301 filter out the invalid set. */
2303 static void
2307 {
2311 /* TYPES[i] is the set of possible builtin-operator parameter types
2312 we will consider for the Ith argument. These are represented as
2313 a TREE_LIST; the TREE_VALUE of each node is the potential
2314 parameter type. */
2318 {
2321 else
2323 }
2326 {
2327 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2328 and VQ is either volatile or empty, there exist candidate operator
2329 functions of the form
2330 VQ T& operator++(VQ T&); */
2340 /* 24There also exist candidate operator functions of the form
2341 bool operator!(bool);
2342 bool operator&&(bool, bool);
2343 bool operator||(bool, bool); */
2346 build_builtin_candidate
2353 build_builtin_candidate
2371 /* Fall through. */
2375 }
2380 {
2382 ;
2384 {
2385 tree convs;
2394 {
2401 }
2407 {
2420 {
2426 }
2430 }
2431 }
2432 else
2433 {
2439 {
2445 }
2447 }
2448 }
2450 /* Run through the possible parameter types of both arguments,
2451 creating candidates with those parameter types. */
2453 {
2456 add_builtin_candidate
2459 else
2460 add_builtin_candidate
2463 }
2464 }
2467 /* If TMPL can be successfully instantiated as indicated by
2468 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2470 TMPL is the template. EXPLICIT_TARGS are any explicit template
2471 arguments. ARGLIST is the arguments provided at the call-site.
2472 This does not change ARGLIST. The RETURN_TYPE is the desired type
2473 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2474 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2475 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2483 {
2493 tree arg;
2496 tree fn;
2498 /* We don't do deduction on the in-charge parameter, the VTT
2499 parameter or 'this'. */
2501 {
2504 else
2506 }
2511 {
2514 else
2516 }
2526 {
2529 }
2533 {
2536 }
2540 args_without_in_chrg,
2541 nargs_without_in_chrg,
2551 /* In [class.copy]:
2553 A member function template is never instantiated to perform the
2554 copy of a class object to an object of its class type.
2556 It's a little unclear what this means; the standard explicitly
2557 does allow a template to be used to copy a class. For example,
2558 in:
2560 struct A {
2561 A(A&);
2562 template <class T> A(const T&);
2563 };
2564 const A f ();
2565 void g () { A a (f ()); }
2567 the member template will be used to make the copy. The section
2568 quoted above appears in the paragraph that forbids constructors
2569 whose only parameter is (a possibly cv-qualified variant of) the
2570 class type, and a logical interpretation is that the intent was
2571 to forbid the instantiation of member templates which would then
2572 have that form. */
2574 {
2577 ctype))
2579 }
2582 /* Aha, this is a conversion function. */
2585 else
2590 /* This situation can occur if a member template of a template
2591 class is specialized. Then, instantiate_template might return
2592 an instantiation of the specialization, in which case the
2593 DECL_TI_TEMPLATE field will point at the original
2594 specialization. For example:
2596 template <class T> struct S { template <class U> void f(U);
2597 template <> void f(int) {}; };
2598 S<double> sd;
2599 sd.f(3);
2601 Here, TMPL will be template <class U> S<double>::f(U).
2602 And, instantiate template will give us the specialization
2603 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2604 for this will point at template <class T> template <> S<T>::f(int),
2605 so that we can find the definition. For the purposes of
2606 overload resolution, however, we want the original TMPL. */
2608 else
2613 fail:
2616 }
2624 unification_kind_t strict)
2625 {
2626 return
2631 }
2639 tree conversion_path)
2640 {
2641 return
2645 }
2647 /* The CANDS are the set of candidates that were considered for
2648 overload resolution. Return the set of viable candidates, or CANDS
2649 if none are viable. If any of the candidates were viable, set
2650 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
2651 considered viable only if it is strictly viable. */
2657 {
2668 {
2671 {
2677 }
2678 else
2680 }
2683 }
2685 static bool
2687 {
2692 }
2694 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2695 words, it is about to become the "this" pointer for a member
2696 function call. Take the address of the object. */
2698 static tree
2700 {
2701 /* In a template, we are only concerned about the type of the
2702 expression, so we can take a shortcut. */
2707 }
2709 /* Returns true iff functions are equivalent. Equivalent functions are
2710 not '==' only if one is a function-local extern function or if
2711 both are extern "C". */
2715 {
2724 }
2726 /* Print information about one overload candidate CANDIDATE. MSGSTR
2727 is the text to print before the candidate itself.
2729 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2730 to have been run through gettext by the caller. This wart makes
2731 life simpler in print_z_candidates and for the translators. */
2733 static void
2735 {
2737 {
2747 else
2750 }
2757 else
2759 }
2761 static void
2763 {
2772 /* Remove non-viable deleted candidates. */
2775 {
2780 else
2782 }
2783 /* ...if there are any non-deleted ones. */
2787 /* There may be duplicates in the set of candidates. We put off
2788 checking this condition as long as possible, since we have no way
2789 to eliminate duplicates from a set of functions in less than n^2
2790 time. Now we are about to emit an error message, so it is more
2791 permissible to go slowly. */
2793 {
2795 /* Skip builtin candidates and conversion functions. */
2800 {
2804 else
2806 }
2807 }
2812 {
2815 }
2817 }
2819 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2820 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2821 the result of the conversion function to convert it to the final
2822 desired type. Merge the two sequences into a single sequence,
2823 and return the merged sequence. */
2827 {
2832 /* Find the end of the second conversion sequence. */
2837 /* Replace the identity conversion with the user conversion
2838 sequence. */
2841 /* The entire sequence is a user-conversion sequence. */
2845 }
2847 /* Handle overload resolution for initializing an object of class type from
2848 an initializer list. First we look for a suitable constructor that
2849 takes a std::initializer_list; if we don't find one, we then look for a
2850 non-list constructor.
2852 Parameters are as for add_candidates, except that the arguments are in
2853 the form of a CONSTRUCTOR (the initializer list) rather than a VEC, and
2854 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
2856 static void
2863 {
2868 /* For list-initialization we consider explicit constructors, but
2869 give an error if one is selected. */
2871 /* And we don't allow narrowing conversions. We also use this flag to
2872 avoid the copy constructor call for copy-list-initialization. */
2875 /* Always use the default constructor if the list is empty (DR 990). */
2878 ;
2879 /* If the class has a list ctor, try passing the list as a single
2880 argument first, but only consider list ctors. */
2882 {
2890 }
2894 /* We aren't looking for list-ctors anymore. */
2896 /* We allow more user-defined conversions within an init-list. */
2898 /* But not for the copy ctor. */
2904 }
2906 /* Returns the best overload candidate to perform the requested
2907 conversion. This function is used for three the overloading situations
2908 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2909 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2910 per [dcl.init.ref], so we ignore temporary bindings. */
2914 {
2925 /* We represent conversion within a hierarchy using RVALUE_CONV and
2926 BASE_CONV, as specified by [over.best.ics]; these become plain
2927 constructor calls, as specified in [dcl.init]. */
2935 {
2940 {
2941 /* [class.conv.fct] A conversion function is never used to
2942 convert a (possibly cv-qualified) object to the (possibly
2943 cv-qualified) same object type (or a reference to it), to a
2944 (possibly cv-qualified) base class of that type (or a
2945 reference to it)... */
2946 }
2947 else
2950 }
2957 /* It's OK to bind a temporary for converting constructor arguments, but
2958 not in converting the return value of a conversion operator. */
2963 {
2969 /* We should never try to call the abstract or base constructor
2970 from here. */
2975 {
2976 /* List-initialization. */
2980 }
2981 else
2982 {
2987 }
2990 {
2993 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
2994 set, then this is copy-initialization. In that case, "The
2995 result of the call is then used to direct-initialize the
2996 object that is the destination of the copy-initialization."
2997 [dcl.init]
2999 We represent this in the conversion sequence with an
3000 rvalue conversion, which means a constructor call. */
3003 cand->second_conv
3005 }
3006 }
3012 {
3016 /* If we are called to convert to a reference type, we are trying to
3017 find an lvalue binding, so don't even consider temporaries. If
3018 we don't find an lvalue binding, the caller will try again to
3019 look for a temporary binding. */
3030 {
3031 conversion *ics
3037 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3038 copy-initialization. In that case, "The result of the
3039 call is then used to direct-initialize the object that is
3040 the destination of the copy-initialization." [dcl.init]
3042 We represent this in the conversion sequence with an
3043 rvalue conversion, which means a constructor call. But
3044 don't add a second rvalue conversion if there's already
3045 one there. Which there really shouldn't be, but it's
3046 harmless since we'd add it here anyway. */
3057 }
3058 }
3066 {
3068 {
3072 }
3079 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3080 ambiguous conversion is no worse than another user-defined
3081 conversion. */
3084 }
3086 /* Build the user conversion sequence. */
3087 conv = build_conv
3094 /* Remember that this was a list-initialization. */
3098 /* Combine it with the second conversion sequence. */
3106 }
3108 tree
3110 {
3115 {
3120 }
3122 }
3124 /* Do any initial processing on the arguments to a function call. */
3128 {
3130 tree arg;
3133 {
3137 {
3140 }
3143 }
3145 }
3147 /* Perform overload resolution on FN, which is called with the ARGS.
3149 Return the candidate function selected by overload resolution, or
3150 NULL if the event that overload resolution failed. In the case
3151 that overload resolution fails, *CANDIDATES will be the set of
3152 candidates considered, and ANY_VIABLE_P will be set to true or
3153 false to indicate whether or not any of the candidates were
3154 viable.
3156 The ARGS should already have gone through RESOLVE_ARGS before this
3157 function is called. */
3164 {
3172 /* Check FN. */
3179 {
3183 }
3185 /* Add the various candidate functions. */
3190 LOOKUP_NORMAL,
3191 candidates);
3199 }
3201 /* Return an expression for a call to FN (a namespace-scope function,
3202 or a static member function) with the ARGS. This may change
3203 ARGS. */
3205 tree
3207 tsubst_flags_t complain)
3208 {
3212 tree result;
3215 {
3219 }
3221 /* If this function was found without using argument dependent
3222 lookup, then we want to ignore any undeclared friend
3223 functions. */
3225 {
3230 {
3236 }
3237 }
3239 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3245 {
3247 {
3256 else
3261 }
3263 }
3264 else
3267 /* Free all the conversions we allocated. */
3271 }
3273 /* Build a call to a global operator new. FNNAME is the name of the
3274 operator (either "operator new" or "operator new[]") and ARGS are
3275 the arguments provided. This may change ARGS. *SIZE points to the
3276 total number of bytes required by the allocation, and is updated if
3277 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
3278 be used. If this function determines that no cookie should be
3279 used, after all, *COOKIE_SIZE is set to NULL_TREE. If FN is
3280 non-NULL, it will be set, upon return, to the allocation function
3281 called. */
3283 tree
3287 {
3288 tree fns;
3300 /* Based on:
3302 [expr.new]
3304 If this lookup fails to find the name, or if the allocated type
3305 is not a class type, the allocation function's name is looked
3306 up in the global scope.
3308 we disregard block-scope declarations of "operator new". */
3311 /* Figure out what function is being called. */
3314 /* If no suitable function could be found, issue an error message
3315 and give up. */
3317 {
3321 else
3327 }
3329 /* If a cookie is required, add some extra space. Whether
3330 or not a cookie is required cannot be determined until
3331 after we know which function was called. */
3333 {
3336 {
3337 /* In G++ 3.2, the check was implemented incorrectly; it
3338 looked at the placement expression, rather than the
3339 type of the function. */
3342 ptr_type_node))
3344 }
3345 else
3346 {
3347 tree arg_types;
3350 /* Skip the size_t parameter. */
3352 /* Check the remaining parameters (if any). */
3356 ptr_type_node))
3358 }
3359 /* If we need a cookie, adjust the number of bytes allocated. */
3361 {
3362 /* Update the total size. */
3364 /* Update the argument list to reflect the adjusted size. */
3366 }
3367 else
3369 }
3371 /* Tell our caller which function we decided to call. */
3375 /* Build the CALL_EXPR. */
3377 }
3379 /* Build a new call to operator(). This may change ARGS. */
3381 tree
3383 {
3397 {
3399 /* It's no good looking for an overloaded operator() on a
3400 pointer-to-member-function. */
3401 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3403 }
3406 {
3410 }
3411 else
3415 {
3419 }
3421 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3425 {
3433 }
3438 {
3450 {
3457 add_template_conv_candidate
3461 else
3465 }
3466 }
3470 {
3472 {
3476 }
3478 }
3479 else
3480 {
3483 {
3485 {
3489 }
3491 }
3492 /* Since cand->fn will be a type, not a function, for a conversion
3493 function, we must be careful not to unconditionally look at
3494 DECL_NAME here. */
3498 else
3499 {
3501 complain);
3504 }
3505 }
3507 /* Free all the conversions we allocated. */
3511 }
3513 static void
3516 {
3521 else
3525 {
3530 else
3540 else
3549 else
3559 else
3569 else
3572 else
3576 else
3580 }
3581 }
3583 /* Return the implicit conversion sequence that could be used to
3584 convert E1 to E2 in [expr.cond]. */
3588 {
3594 /* [expr.cond]
3596 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3597 implicitly converted (clause _conv_) to the type "reference to
3598 T2", subject to the constraint that in the conversion the
3599 reference must bind directly (_dcl.init.ref_) to E1. */
3601 {
3603 t1,
3604 e1,
3609 }
3611 /* [expr.cond]
3613 If E1 and E2 have class type, and the underlying class types are
3614 the same or one is a base class of the other: E1 can be converted
3615 to match E2 if the class of T2 is the same type as, or a base
3616 class of, the class of T1, and the cv-qualification of T2 is the
3617 same cv-qualification as, or a greater cv-qualification than, the
3618 cv-qualification of T1. If the conversion is applied, E1 is
3619 changed to an rvalue of type T2 that still refers to the original
3620 source class object (or the appropriate subobject thereof). */
3623 {
3625 {
3630 else
3633 }
3634 else
3636 }
3637 else
3638 /* [expr.cond]
3640 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3641 converted to the type that expression E2 would have if E2 were
3642 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3644 LOOKUP_IMPLICIT);
3645 }
3647 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3648 arguments to the conditional expression. */
3650 tree
3652 tsubst_flags_t complain)
3653 {
3654 tree arg2_type;
3655 tree arg3_type;
3663 /* As a G++ extension, the second argument to the conditional can be
3664 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3665 c'.) If the second operand is omitted, make sure it is
3666 calculated only once. */
3668 {
3673 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3676 else
3678 }
3680 /* [expr.cond]
3682 The first expression is implicitly converted to bool (clause
3683 _conv_). */
3685 LOOKUP_NORMAL);
3687 /* If something has already gone wrong, just pass that fact up the
3688 tree. */
3694 /* [expr.cond]
3696 If either the second or the third operand has type (possibly
3697 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3698 array-to-pointer (_conv.array_), and function-to-pointer
3699 (_conv.func_) standard conversions are performed on the second
3700 and third operands. */
3704 {
3705 /* Do the conversions. We don't these for `void' type arguments
3706 since it can't have any effect and since decay_conversion
3707 does not handle that case gracefully. */
3715 /* [expr.cond]
3717 One of the following shall hold:
3719 --The second or the third operand (but not both) is a
3720 throw-expression (_except.throw_); the result is of the
3721 type of the other and is an rvalue.
3723 --Both the second and the third operands have type void; the
3724 result is of type void and is an rvalue.
3726 We must avoid calling force_rvalue for expressions of type
3727 "void" because it will complain that their value is being
3728 used. */
3731 {
3736 }
3739 {
3744 }
3747 else
3748 {
3750 {
3753 "is of type %<void%>, "
3754 "but the third operand is neither a throw-expression "
3756 else
3758 "is of type %<void%>, "
3759 "but the second operand is neither a throw-expression "
3761 }
3763 }
3767 }
3768 /* [expr.cond]
3770 Otherwise, if the second and third operand have different types,
3771 and either has (possibly cv-qualified) class type, an attempt is
3772 made to convert each of those operands to the type of the other. */
3775 {
3779 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3785 /* [expr.cond]
3787 If both can be converted, or one can be converted but the
3788 conversion is ambiguous, the program is ill-formed. If
3789 neither can be converted, the operands are left unchanged and
3790 further checking is performed as described below. If exactly
3791 one conversion is possible, that conversion is applied to the
3792 chosen operand and the converted operand is used in place of
3793 the original operand for the remainder of this section. */
3798 {
3802 }
3804 {
3808 /* Even if CONV2 is a valid conversion, the result of the
3809 conversion may be invalid. For example, if ARG3 has type
3810 "volatile X", and X does not have a copy constructor
3811 accepting a "volatile X&", then even if ARG2 can be
3812 converted to X, the conversion will fail. */
3815 }
3817 {
3823 }
3825 /* Free all the conversions we allocated. */
3831 /* If, after the conversion, both operands have class type,
3832 treat the cv-qualification of both operands as if it were the
3833 union of the cv-qualification of the operands.
3835 The standard is not clear about what to do in this
3836 circumstance. For example, if the first operand has type
3837 "const X" and the second operand has a user-defined
3838 conversion to "volatile X", what is the type of the second
3839 operand after this step? Making it be "const X" (matching
3840 the first operand) seems wrong, as that discards the
3841 qualification without actually performing a copy. Leaving it
3842 as "volatile X" seems wrong as that will result in the
3843 conditional expression failing altogether, even though,
3844 according to this step, the one operand could be converted to
3845 the type of the other. */
3853 }
3855 /* [expr.cond]
3857 If the second and third operands are lvalues and have the same
3858 type, the result is of that type and is an lvalue. */
3862 {
3867 }
3869 /* [expr.cond]
3871 Otherwise, the result is an rvalue. If the second and third
3872 operand do not have the same type, and either has (possibly
3873 cv-qualified) class type, overload resolution is used to
3874 determine the conversions (if any) to be applied to the operands
3875 (_over.match.oper_, _over.built_). */
3879 {
3884 /* Rearrange the arguments so that add_builtin_candidate only has
3885 to know about two args. In build_builtin_candidate, the
3886 arguments are unscrambled. */
3891 COND_EXPR,
3892 NOP_EXPR,
3894 args,
3895 LOOKUP_NORMAL);
3897 /* [expr.cond]
3899 If the overload resolution fails, the program is
3900 ill-formed. */
3903 {
3905 {
3908 }
3910 }
3913 {
3915 {
3918 }
3920 }
3922 /* [expr.cond]
3924 Otherwise, the conversions thus determined are applied, and
3925 the converted operands are used in place of the original
3926 operands for the remainder of this section. */
3935 }
3937 /* [expr.cond]
3939 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3940 and function-to-pointer (_conv.func_) standard conversions are
3941 performed on the second and third operands.
3943 We need to force the lvalue-to-rvalue conversion here for class types,
3944 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3945 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3946 regions. */
3959 /* [expr.cond]
3961 After those conversions, one of the following shall hold:
3963 --The second and third operands have the same type; the result is of
3964 that type. */
3967 /* [expr.cond]
3969 --The second and third operands have arithmetic or enumeration
3970 type; the usual arithmetic conversions are performed to bring
3971 them to a common type, and the result is of that type. */
3976 {
3977 /* In this case, there is always a common type. */
3979 arg3_type);
3983 {
3988 }
3994 {
3998 }
4002 }
4003 /* [expr.cond]
4005 --The second and third operands have pointer type, or one has
4006 pointer type and the other is a null pointer constant; pointer
4007 conversions (_conv.ptr_) and qualification conversions
4008 (_conv.qual_) are performed to bring them to their composite
4009 pointer type (_expr.rel_). The result is of the composite
4010 pointer type.
4012 --The second and third operands have pointer to member type, or
4013 one has pointer to member type and the other is a null pointer
4014 constant; pointer to member conversions (_conv.mem_) and
4015 qualification conversions (_conv.qual_) are performed to bring
4016 them to a common type, whose cv-qualification shall match the
4017 cv-qualification of either the second or the third operand.
4018 The result is of the common type. */
4026 {
4029 complain);
4034 }
4037 {
4042 }
4044 valid_operands:
4047 /* Avoid folding within decltype (c++/42013) and noexcept. */
4050 /* We can't use result_type below, as fold might have returned a
4051 throw_expr. */
4054 {
4055 /* Expand both sides into the same slot, hopefully the target of
4056 the ?: expression. We used to check for TARGET_EXPRs here,
4057 but now we sometimes wrap them in NOP_EXPRs so the test would
4058 fail. */
4061 /* If this expression is an rvalue, but might be mistaken for an
4062 lvalue, we must add a NON_LVALUE_EXPR. */
4064 }
4067 }
4069 /* OPERAND is an operand to an expression. Perform necessary steps
4070 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
4071 returned. */
4073 static tree
4075 {
4077 {
4080 /* Make sure the template type is instantiated now. */
4082 }
4085 }
4087 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
4088 OVERLOAD) to the CANDIDATES, returning an updated list of
4089 CANDIDATES. The ARGS are the arguments provided to the call;
4090 if FIRST_ARG is non-null it is the implicit object argument,
4091 otherwise the first element of ARGS is used if needed. The
4092 EXPLICIT_TARGS are explicit template arguments provided.
4093 TEMPLATE_ONLY is true if only template functions should be
4094 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
4095 add_function_candidate. */
4097 static void
4099 tree return_type,
4104 {
4105 tree ctype;
4109 unification_kind_t strict;
4110 tree fn;
4115 /* Precalculate special handling of constructors and conversion ops. */
4118 {
4122 /* We're doing return_type(x). */
4124 else
4125 /* We're doing x.operator return_type(). */
4127 /* [over.match.funcs] For conversion functions, the function
4128 is considered to be a member of the class of the implicit
4129 object argument for the purpose of defining the type of
4130 the implicit object parameter. */
4132 }
4133 else
4134 {
4136 {
4139 }
4140 else
4141 {
4144 }
4147 }
4151 else
4152 /* Delay creating the implicit this parameter until it is needed. */
4156 {
4157 tree fn_first_arg;
4167 /* Figure out which set of arguments to use. */
4169 {
4170 /* If this function is a non-static member and we didn't get an
4171 implicit object argument, move it out of args. */
4173 {
4175 tree arg;
4182 }
4186 }
4187 else
4188 {
4189 /* Otherwise, just use the list of arguments provided. */
4192 }
4196 fn,
4197 ctype,
4198 explicit_targs,
4199 fn_first_arg,
4200 fn_args,
4201 return_type,
4202 access_path,
4203 conversion_path,
4204 flags,
4205 strict);
4208 fn,
4209 ctype,
4210 fn_first_arg,
4211 fn_args,
4212 access_path,
4213 conversion_path,
4214 flags);
4215 }
4216 }
4218 /* Even unsigned enum types promote to signed int. We don't want to
4219 issue -Wsign-compare warnings for this case. Here ORIG_ARG is the
4220 original argument and ARG is the argument after any conversions
4221 have been applied. We set TREE_NO_WARNING if we have added a cast
4222 from an unsigned enum type to a signed integer type. */
4224 static void
4226 {
4235 }
4237 tree
4240 {
4246 tree fnname;
4264 {
4268 }
4269 else
4275 {
4280 /* Use build_op_new_call and build_op_delete_call instead. */
4284 /* Use build_op_call instead. */
4291 /* These are saved for the sake of warn_logical_operator. */
4297 }
4303 /* Use build_conditional_expr instead. */
4319 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4322 /* Add namespace-scope operators to the list of functions to
4323 consider. */
4328 /* Add class-member operators to the candidate set. */
4330 {
4331 tree fns;
4335 {
4338 }
4346 }
4355 {
4358 /* For these, the built-in candidates set is empty
4359 [over.match.oper]/3. We don't want non-strict matches
4360 because exact matches are always possible with built-in
4361 operators. The built-in candidate set for COMPONENT_REF
4362 would be empty too, but since there are no such built-in
4363 operators, we accept non-strict matches for them. */
4370 }
4374 {
4376 {
4379 /* Don't try anything fancy if we're not allowed to produce
4380 errors. */
4384 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
4385 distinguish between prefix and postfix ++ and
4386 operator++() was used for both, so we allow this with
4387 -fpermissive. */
4389 {
4396 }
4403 else
4409 /* The caller will deal with these. */
4419 {
4420 /* If one of the arguments of the operator represents
4421 an invalid use of member function pointer, try to report
4422 a meaningful error ... */
4427 else
4428 {
4429 /* ... Otherwise, report the more generic
4430 "no matching operator found" error */
4433 }
4434 }
4437 }
4438 }
4439 else
4440 {
4443 {
4445 {
4448 }
4450 }
4452 {
4458 else
4460 }
4461 else
4462 {
4463 /* Give any warnings we noticed during overload resolution. */
4465 {
4469 }
4471 /* Check for comparison of different enum types. */
4473 {
4485 {
4489 }
4493 }
4495 /* We need to strip any leading REF_BIND so that bitfields
4496 don't cause errors. This should not remove any important
4497 conversions, because builtins don't apply to class
4498 objects directly. */
4505 {
4506 /* We need to call warn_logical_operator before
4507 converting arg2 to a boolean_type. */
4517 }
4519 {
4524 }
4526 }
4527 }
4529 user_defined_result_ready:
4531 /* Free all the conversions we allocated. */
4537 builtin:
4543 {
4556 /* Fall through. */
4594 complain),
4595 arg2);
4597 /* The caller will deal with these. */
4605 }
4607 }
4609 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
4610 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
4612 static bool
4614 {
4615 /* A template instance is never a usual deallocation function,
4616 regardless of its signature. */
4621 /* If a class T has a member deallocation function named operator delete
4622 with exactly one parameter, then that function is a usual
4623 (non-placement) deallocation function. If class T does not declare
4624 such an operator delete but does declare a member deallocation
4625 function named operator delete with exactly two parameters, the second
4626 of which has type std::size_t (18.2), then this function is a usual
4627 deallocation function. */
4634 }
4636 /* Build a call to operator delete. This has to be handled very specially,
4637 because the restrictions on what signatures match are different from all
4638 other call instances. For a normal delete, only a delete taking (void *)
4639 or (void *, size_t) is accepted. For a placement delete, only an exact
4640 match with the placement new is accepted.
4642 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4643 ADDR is the pointer to be deleted.
4644 SIZE is the size of the memory block to be deleted.
4645 GLOBAL_P is true if the delete-expression should not consider
4646 class-specific delete operators.
4647 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4649 If this call to "operator delete" is being generated as part to
4650 deallocate memory allocated via a new-expression (as per [expr.new]
4651 which requires that if the initialization throws an exception then
4652 we call a deallocation function), then ALLOC_FN is the allocation
4653 function. */
4655 tree
4658 tree alloc_fn)
4659 {
4673 /* In [class.free]
4675 If the result of the lookup is ambiguous or inaccessible, or if
4676 the lookup selects a placement deallocation function, the
4677 program is ill-formed.
4679 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4680 {
4684 }
4685 else
4691 /* Strip const and volatile from addr. */
4695 {
4696 /* "A declaration of a placement deallocation function matches the
4697 declaration of a placement allocation function if it has the same
4698 number of parameters and, after parameter transformations (8.3.5),
4699 all parameter types except the first are identical."
4701 So we build up the function type we want and ask instantiate_type
4702 to get it for us. */
4714 /* "If the lookup finds the two-parameter form of a usual deallocation
4715 function (3.7.4.2) and that function, considered as a placement
4716 deallocation function, would have been selected as a match for the
4717 allocation function, the program is ill-formed." */
4719 {
4720 /* But if the class has an operator delete (void *), then that is
4721 the usual deallocation function, so we shouldn't complain
4722 about using the operator delete (void *, size_t). */
4725 {
4730 }
4733 ok:;
4734 }
4735 }
4736 else
4737 /* "Any non-placement deallocation function matches a non-placement
4738 allocation function. If the lookup finds a single matching
4739 deallocation function, that function will be called; otherwise, no
4740 deallocation function will be called." */
4743 {
4746 {
4748 /* "If a class T has a member deallocation function named
4749 operator delete with exactly one parameter, then that
4750 function is a usual (non-placement) deallocation
4751 function. If class T does not declare such an operator
4752 delete but does declare a member deallocation function named
4753 operator delete with exactly two parameters, the second of
4754 which has type std::size_t (18.2), then this function is a
4755 usual deallocation function."
4757 So (void*) beats (void*, size_t). */
4760 }
4761 }
4763 /* If we have a matching function, call it. */
4765 {
4768 /* If the FN is a member function, make sure that it is
4769 accessible. */
4773 /* Core issue 901: It's ok to new a type with deleted delete. */
4778 {
4779 /* The placement args might not be suitable for overload
4780 resolution at this point, so build the call directly. */
4789 }
4790 else
4791 {
4792 tree ret;
4800 }
4801 }
4803 /* [expr.new]
4805 If no unambiguous matching deallocation function can be found,
4806 propagating the exception does not cause the object's memory to
4807 be freed. */
4809 {
4812 alloc_fn);
4814 }
4819 }
4821 /* If the current scope isn't allowed to access DECL along
4822 BASETYPE_PATH, give an error. The most derived class in
4823 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4824 the declaration to use in the error diagnostic. */
4826 bool
4828 {
4832 {
4837 else
4841 }
4844 }
4846 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4847 bitwise or of LOOKUP_* values. If any errors are warnings are
4848 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4849 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4850 to NULL. */
4852 static tree
4855 {
4868 else
4871 }
4873 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
4874 EXPR is implicitly converted to type TOTYPE.
4875 FN and ARGNUM are used for diagnostics. */
4877 static void
4879 {
4882 /* Issue warnings about peculiar, but valid, uses of NULL. */
4884 {
4889 else
4892 }
4894 /* Issue warnings if "false" is converted to a NULL pointer */
4899 }
4901 /* Perform the conversions in CONVS on the expression EXPR. FN and
4902 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4903 indicates the `this' argument of a method. INNER is nonzero when
4904 being called to continue a conversion chain. It is negative when a
4905 reference binding will be applied, positive otherwise. If
4906 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4907 conversions will be emitted if appropriate. If C_CAST_P is true,
4908 this conversion is coming from a C-style cast; in that case,
4909 conversions to inaccessible bases are permitted. */
4911 static tree
4915 {
4917 diagnostic_t diag_kind;
4927 {
4930 /* Give a helpful error if this is bad because of excess braces. */
4938 {
4940 {
4944 complain);
4946 }
4951 complain);
4954 }
4956 {
4961 }
4962 else
4966 }
4972 {
4974 {
4981 /* When converting from an init list we consider explicit
4982 constructors, but actually trying to call one is an error. */
4984 /* Unless we're calling it for value-initialization from an
4985 empty list, since that is handled separately in 8.5.4. */
4987 {
4991 else
4993 }
4995 /* Set user_conv_p on the argument conversions, so rvalue/base
4996 handling knows not to allow any more UDCs. */
5002 /* If this is a constructor or a function returning an aggr type,
5003 we need to build up a TARGET_EXPR. */
5005 {
5008 /* Remember that this was list-initialization. */
5011 }
5014 }
5018 {
5024 else
5026 }
5030 /* Convert a constant to its underlying value, unless we are
5031 about to bind it to a reference, in which case we need to
5032 leave it as an lvalue. */
5034 {
5037 /* If __null has been converted to an integer type, we do not
5038 want to warn about uses of EXPR as an integer, rather than
5039 as a pointer. */
5041 }
5045 {
5046 /* Call build_user_type_conversion again for the error. */
5050 }
5054 {
5055 /* Conversion to std::initializer_list<T>. */
5063 /* Convert all the elements. */
5065 {
5072 }
5073 /* Build up the array. */
5074 elttype = cp_build_qualified_type
5082 /* Call the private constructor. */
5084 new_ctor = build_special_member_call
5089 }
5096 };
5101 c_cast_p,
5102 complain);
5107 {
5112 /* Else fall through. */
5115 {
5116 /* We are going to bind a reference directly to a base-class
5117 subobject of EXPR. */
5118 /* Build an expression for `*((base*) &expr)'. */
5124 }
5126 /* Copy-initialization where the cv-unqualified version of the source
5127 type is the same class as, or a derived class of, the class of the
5128 destination [is treated as direct-initialization]. [dcl.init] */
5131 /* This conversion is being done in the context of a user-defined
5132 conversion (i.e. the second step of copy-initialization), so
5133 don't allow any more. */
5137 {
5143 }
5147 {
5152 {
5154 {
5159 }
5161 }
5163 /* If necessary, create a temporary.
5165 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
5166 that need temporaries, even when their types are reference
5167 compatible with the type of reference being bound, so the
5168 upcoming call to cp_build_unary_op (ADDR_EXPR, expr, ...)
5169 doesn't fail. */
5173 {
5179 {
5181 {
5182 /* If the reference is volatile or non-const, we
5183 cannot create a temporary. */
5190 else
5192 }
5194 }
5195 /* If the source is a packed field, and we must use a copy
5196 constructor, then building the target expr will require
5197 binding the field to the reference parameter to the
5198 copy constructor, and we'll end up with an infinite
5199 loop. If we can use a bitwise copy, then we'll be
5200 OK. */
5204 {
5209 }
5211 {
5214 }
5216 }
5218 /* Take the address of the thing to which we will bind the
5219 reference. */
5224 /* Convert it to a pointer to the type referred to by the
5225 reference. This will adjust the pointer if a derived to
5226 base conversion is being performed. */
5228 expr);
5229 /* Convert the pointer to the desired reference type. */
5231 }
5237 /* Warn about deprecated conversion if appropriate. */
5249 c_cast_p);
5253 }
5260 else
5264 }
5266 /* ARG is being passed to a varargs function. Perform any conversions
5267 required. Return the converted value. */
5269 tree
5271 {
5272 /* [expr.call]
5274 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5275 standard conversions are performed. */
5277 /* [expr.call]
5279 If the argument has integral or enumeration type that is subject
5280 to the integral promotions (_conv.prom_), or a floating point
5281 type that is subject to the floating point promotion
5282 (_conv.fpprom_), the value of the argument is converted to the
5283 promoted type before the call. */
5299 {
5300 /* [expr.call] 5.2.2/7:
5301 Passing a potentially-evaluated argument of class type (Clause 9)
5302 with a non-trivial copy constructor or a non-trivial destructor
5303 with no corresponding parameter is conditionally-supported, with
5304 implementation-defined semantics.
5306 We used to just warn here and do a bitwise copy, but now
5307 cp_expr_size will abort if we try to do that.
5309 If the call appears in the context of a sizeof expression,
5310 it is not potentially-evaluated. */
5314 }
5317 }
5319 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
5321 tree
5323 {
5337 {
5338 /* Remove reference types so we don't ICE later on. */
5340 /* conditionally-supported behavior [expr.call] 5.2.2/7. */
5346 }
5349 }
5351 /* TYPE has been given to va_arg. Apply the default conversions which
5352 would have happened when passed via ellipsis. Return the promoted
5353 type, or the passed type if there is no change. */
5355 tree
5357 {
5358 tree promote;
5360 /* Perform the array-to-pointer and function-to-pointer
5361 conversions. */
5369 }
5371 /* ARG is a default argument expression being passed to a parameter of
5372 the indicated TYPE, which is a parameter to FN. Do any required
5373 conversions. Return the converted value. */
5377 tree
5379 {
5381 tree t;
5383 /* If the ARG is an unparsed default argument expression, the
5384 conversion cannot be performed. */
5386 {
5391 }
5393 /* Detect recursion. */
5396 {
5399 }
5405 /* Due to:
5407 [dcl.fct.default]
5409 The names in the expression are bound, and the semantic
5410 constraints are checked, at the point where the default
5411 expressions appears.
5413 we must not perform access checks here. */
5417 {
5421 tf_warning_or_error);
5422 }
5423 else
5424 {
5425 /* We must make a copy of ARG, in case subsequent processing
5426 alters any part of it. For example, during gimplification a
5427 cast of the form (T) &X::f (where "f" is a member function)
5428 will lead to replacing the PTRMEM_CST for &X::f with a
5429 VAR_DECL. We can avoid the copy for constants, since they
5430 are never modified in place. */
5435 tf_warning_or_error);
5437 }
5443 }
5445 /* Returns the type which will really be used for passing an argument of
5446 type TYPE. */
5448 tree
5450 {
5451 /* Pass classes with copy ctors by invisible reference. */
5453 {
5455 /* There are no other pointers to this temporary. */
5457 }
5466 }
5468 /* Actually perform the appropriate conversion. */
5470 tree
5472 {
5473 tree bitfield_type;
5475 /* If VAL is a bitfield, then -- since it has already been converted
5476 to TYPE -- it cannot have a precision greater than TYPE.
5478 If it has a smaller precision, we must widen it here. For
5479 example, passing "int f:3;" to a function expecting an "int" will
5480 not result in any conversion before this point.
5482 If the precision is the same we must not risk widening. For
5483 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
5484 often have type "int", even though the C++ type for the field is
5485 "long long". If the value is being passed to a function
5486 expecting an "int", then no conversions will be required. But,
5487 if we call convert_bitfield_to_declared_type, the bitfield will
5488 be converted to "long long". */
5495 ;
5496 /* Pass classes with copy ctors by invisible reference. */
5506 {
5515 }
5517 }
5519 /* Returns true iff FN is a function with magic varargs, i.e. ones for
5520 which no conversions at all should be done. This is true for some
5521 builtins which don't act like normal functions. */
5523 static bool
5525 {
5528 {
5538 }
5541 }
5543 /* Subroutine of the various build_*_call functions. Overload resolution
5544 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
5545 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
5546 bitmask of various LOOKUP_* flags which apply to the call itself. */
5548 static tree
5550 {
5558 tree val;
5567 /* In a template, there is no need to perform all of the work that
5568 is normally done. We are only interested in the type of the call
5569 expression, i.e., the return type of the function. Any semantic
5570 errors will be deferred until the template is instantiated. */
5572 {
5573 tree expr;
5574 tree return_type;
5582 else
5583 {
5586 tree arg;
5594 }
5597 argarray);
5603 }
5605 /* Give any warnings we noticed during overload resolution. */
5607 {
5611 }
5613 /* Make =delete work with SFINAE. */
5618 {
5619 tree access_fn;
5620 /* If FN is a template function, two cases must be considered.
5621 For example:
5623 struct A {
5624 protected:
5625 template <class T> void f();
5626 };
5627 template <class T> struct B {
5628 protected:
5629 void g();
5630 };
5631 struct C : A, B<int> {
5632 using A::f; // #1
5633 using B<int>::g; // #2
5634 };
5636 In case #1 where `A::f' is a member template, DECL_ACCESS is
5637 recorded in the primary template but not in its specialization.
5638 We check access of FN using its primary template.
5640 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
5641 because it is a member of class template B, DECL_ACCESS is
5642 recorded in the specialization `B<int>::g'. We cannot use its
5643 primary template because `B<T>::g' and `B<int>::g' may have
5644 different access. */
5648 else
5651 {
5652 /* If we're checking for implicit delete, we don't want access
5653 control errors. */
5655 {
5656 /* Unless we're under maybe_explain_implicit_delete. */
5660 }
5661 }
5662 else
5664 }
5666 /* If we're checking for implicit delete, don't bother with argument
5667 conversions. */
5669 {
5671 {
5675 }
5679 /* Reject bad conversions now. */
5681 /* else continue to get conversion error. */
5682 }
5684 /* Find maximum size of vector to hold converted arguments. */
5691 /* The implicit parameters to a constructor are not considered by overload
5692 resolution, and must be of the proper type. */
5694 {
5696 {
5699 }
5700 else
5701 {
5704 }
5706 /* We should never try to call the abstract constructor. */
5710 {
5714 }
5715 }
5716 /* Bypass access control for 'this' parameter. */
5718 {
5721 ? first_arg
5724 tree converted_arg;
5725 tree base_binfo;
5728 {
5732 else
5734 }
5736 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
5737 X is called for an object that is not of type X, or of a type
5738 derived from X, the behavior is undefined.
5740 So we can assume that anything passed as 'this' is non-null, and
5741 optimize accordingly. */
5743 /* Convert to the base in which the function was declared. */
5746 arg,
5749 /* Check that the base class is accessible. */
5755 /* If fn was found by a using declaration, the conversion path
5756 will be to the derived class, not the base declaring fn. We
5757 must convert from derived to base. */
5767 else
5771 }
5776 {
5782 /* Don't make a copy here if build_call is going to. */
5788 /* Warn about initializer_list deduction that isn't currently in the
5789 working draft. */
5791 && flag_deduce_init_list
5795 {
5808 {
5815 }
5816 }
5823 else
5825 }
5827 /* Default arguments */
5832 /* Ellipsis */
5834 {
5837 /* Do no conversions for magic varargs. */
5839 else
5842 }
5850 /* Avoid actually calling copy constructors and copy assignment operators,
5851 if possible. */
5858 {
5859 tree targ;
5861 tree fa;
5864 /* Pull out the real argument, disregarding const-correctness. */
5870 {
5875 }
5876 else
5881 else
5886 {
5887 /* Copy-list-initialization doesn't require the constructor
5888 to be defined. */
5889 }
5890 /* [class.copy]: the copy constructor is implicitly defined even if
5891 the implementation elided its use. */
5893 {
5896 }
5898 /* If we're creating a temp and we already have one, don't create a
5899 new one. If we're not creating a temp but we get one, use
5900 INIT_EXPR to collapse the temp into our target. Otherwise, if the
5901 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
5902 temp or an INIT_EXPR otherwise. */
5907 {
5912 }
5914 {
5916 complain));
5920 }
5921 }
5924 {
5925 tree to = stabilize_reference
5932 {
5933 /* Avoid copying empty classes. */
5938 }
5940 {
5943 }
5944 else
5945 {
5946 /* We must only copy the non-tail padding parts.
5947 Use __builtin_memcpy for the bitwise copy.
5948 FIXME fix 22488 so we can go back to using MODIFY_EXPR
5949 instead of an explicit call to memcpy. */
5959 {
5960 /* If we can't be sure about pointer alignment, a call
5961 to __builtin_memcpy is expanded as a call to memcpy, which
5962 is invalid with identical args. Otherwise it is
5963 expanded as a block move, which should be safe. */
5967 }
5976 }
5979 }
5985 {
5986 tree t;
5992 /* Warn about deprecated virtual functions now, since we're about
5993 to throw away the decl. */
6003 else
6006 }
6007 else
6011 }
6013 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
6014 This function performs no overload resolution, conversion, or other
6015 high-level operations. */
6017 tree
6019 {
6020 tree fndecl;
6024 /* If this call might throw an exception, note that fact. */
6031 /* Check that arguments to builtin functions match the expectations. */
6038 /* Some built-in function calls will be evaluated at compile-time in
6039 fold (). */
6052 }
6056 /* Make an expression which yields the address of the Java interface
6057 method FN. This is achieved by generating a call to libjava's
6058 _Jv_LookupInterfaceMethodIdx(). */
6060 static tree
6062 {
6068 {
6072 java_iface_lookup_fn
6075 }
6077 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
6078 This is the first entry in the vtable. */
6080 tf_warning_or_error),
6081 integer_zero_node);
6083 /* Get the java.lang.Class pointer for the interface being called. */
6088 {
6090 iface);
6092 }
6096 /* Determine the itable index of FN. */
6099 {
6104 i++;
6105 }
6110 java_iface_lookup_fn);
6113 }
6115 /* Returns the value to use for the in-charge parameter when making a
6116 call to a function with the indicated NAME.
6118 FIXME:Can't we find a neater way to do this mapping? */
6120 tree
6122 {
6133 /* This function should only be called with one of the names listed
6134 above. */
6137 }
6139 /* Build a call to a constructor, destructor, or an assignment
6140 operator for INSTANCE, an expression with class type. NAME
6141 indicates the special member function to call; *ARGS are the
6142 arguments. ARGS may be NULL. This may change ARGS. BINFO
6143 indicates the base of INSTANCE that is to be passed as the `this'
6144 parameter to the member function called.
6146 FLAGS are the LOOKUP_* flags to use when processing the call.
6148 If NAME indicates a complete object constructor, INSTANCE may be
6149 NULL_TREE. In this case, the caller will call build_cplus_new to
6150 store the newly constructed object into a VAR_DECL. */
6152 tree
6155 {
6156 tree fns;
6157 /* The type of the subobject to be constructed or destroyed. */
6158 tree class_type;
6160 tree ret;
6169 {
6170 /* Resolve the name. */
6175 }
6181 /* Handle the special case where INSTANCE is NULL_TREE. */
6183 {
6186 }
6187 else
6188 {
6194 /* Convert to the base class, if necessary. */
6197 {
6199 /* For constructors and destructors, either the base is
6200 non-virtual, or it is virtual but we are doing the
6201 conversion from a constructor or destructor for the
6202 complete object. In either case, we can convert
6203 statically. */
6205 else
6206 /* However, for assignment operators, we must convert
6207 dynamically if the base is virtual. */
6210 }
6211 }
6217 /* When making a call to a constructor or destructor for a subobject
6218 that uses virtual base classes, pass down a pointer to a VTT for
6219 the subobject. */
6223 {
6224 tree vtt;
6225 tree sub_vtt;
6227 /* If the current function is a complete object constructor
6228 or destructor, then we fetch the VTT directly.
6229 Otherwise, we look it up using the VTT we were given. */
6235 current_vtt_parm,
6236 vtt);
6242 {
6245 }
6248 }
6253 complain);
6259 }
6261 /* Return the NAME, as a C string. The NAME indicates a function that
6262 is a member of TYPE. *FREE_P is set to true if the caller must
6263 free the memory returned.
6265 Rather than go through all of this, we should simply set the names
6266 of constructors and destructors appropriately, and dispense with
6267 ctor_identifier, dtor_identifier, etc. */
6271 {
6274 /* Assume that we will not allocate memory. */
6276 /* Constructors and destructors are special. */
6278 {
6279 pretty_name
6281 /* For a destructor, add the '~'. */
6285 {
6287 /* Remember that we need to free the memory allocated. */
6289 }
6290 }
6292 {
6295 TFF_PLAIN_IDENTIFIER),
6296 NULL);
6297 /* Remember that we need to free the memory allocated. */
6299 }
6300 else
6304 }
6306 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
6307 be set, upon return, to the function called. ARGS may be NULL.
6308 This may change ARGS. */
6310 tree
6314 {
6318 tree access_binfo;
6319 tree optype;
6321 tree instance_ptr;
6322 tree name;
6325 tree call;
6326 tree fn;
6329 tree orig_instance;
6330 tree orig_fns;
6336 /* We don't know what function we're going to call, yet. */
6345 {
6349 }
6354 /* Dismantle the baselink to collect all the information we need. */
6361 {
6365 }
6376 {
6381 }
6384 /* Under DR 147 A::A() is an invalid constructor call,
6385 not a functional cast. */
6387 {
6397 complain);
6399 }
6401 /* Figure out whether to skip the first argument for the error
6402 message we will display to users if an error occurs. We don't
6403 want to display any compiler-generated arguments. The "this"
6404 pointer hasn't been added yet. However, we must remove the VTT
6405 pointer if this is a call to a base-class constructor or
6406 destructor. */
6409 {
6410 /* Callers should explicitly indicate whether they want to construct
6411 the complete object or just the part without virtual bases. */
6413 /* Similarly for destructors. */
6415 /* Remove the VTT pointer, if present. */
6419 }
6421 /* Process the argument list. */
6423 {
6427 }
6431 /* It's OK to call destructors and constructors on cv-qualified objects.
6432 Therefore, convert the INSTANCE_PTR to the unqualified type, if
6433 necessary. */
6436 {
6440 }
6446 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6449 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
6450 initializer, not T({ }). */
6454 {
6461 }
6462 else
6463 {
6467 }
6472 {
6474 {
6481 else
6482 {
6485 tree arglist;
6496 }
6498 }
6500 }
6501 else
6502 {
6505 {
6508 tree arglist;
6511 {
6517 arglist);
6521 }
6523 }
6524 else
6525 {
6534 /* This is not an error, it is runtime undefined
6535 behavior. */
6537 "pure virtual %q#D called from constructor"
6539 fn);
6543 {
6546 fn);
6548 }
6549 else
6550 {
6554 /* Now we know what function is being called. */
6557 /* Build the actual CALL_EXPR. */
6559 /* In an expression of the form `a->f()' where `f' turns
6560 out to be a static member function, `a' is
6561 none-the-less evaluated. */
6570 /* An explicit call of the form "x->~X()" has type
6571 "void". However, on platforms where destructors
6572 return "this" (i.e., those where
6573 targetm.cxx.cdtor_returns_this is true), such calls
6574 will appear to have a return value of pointer type
6575 to the low-level call machinery. We do not want to
6576 change the low-level machinery, since we want to be
6577 able to optimize "delete f()" on such platforms as
6578 "operator delete(~X(f()))" (rather than generating
6579 "t = f(), ~X(t), operator delete (t)"). */
6581 }
6582 }
6583 }
6586 {
6592 {
6595 }
6598 call = (build_min_non_dep_call_vec
6602 orig_args));
6606 }
6608 /* Free all the conversions we allocated. */
6615 }
6617 /* Returns true iff standard conversion sequence ICS1 is a proper
6618 subsequence of ICS2. */
6620 static bool
6622 {
6623 /* We can assume that a conversion of the same code
6624 between the same types indicates a subsequence since we only get
6625 here if the types we are converting from are the same. */
6632 {
6642 /* At this point, ICS1 cannot be a proper subsequence of
6643 ICS2. We can get a USER_CONV when we are comparing the
6644 second standard conversion sequence of two user conversion
6645 sequences. */
6655 }
6656 }
6658 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
6659 be any _TYPE nodes. */
6661 bool
6663 {
6667 /* We only allow proper derivation here. The DERIVED_FROM_P macro
6668 considers every class derived from itself. */
6671 }
6673 /* We build the ICS for an implicit object parameter as a pointer
6674 conversion sequence. However, such a sequence should be compared
6675 as if it were a reference conversion sequence. If ICS is the
6676 implicit conversion sequence for an implicit object parameter,
6677 modify it accordingly. */
6679 static void
6681 {
6683 {
6684 /* [over.match.funcs]
6686 For non-static member functions, the type of the
6687 implicit object parameter is "reference to cv X"
6688 where X is the class of which the function is a
6689 member and cv is the cv-qualification on the member
6690 function declaration. */
6692 tree reference_type;
6694 /* The `this' parameter is a pointer to a class type. Make the
6695 implicit conversion talk about a reference to that same class
6696 type. */
6709 }
6710 }
6712 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
6713 and return the initial reference binding conversion. Otherwise,
6714 leave *ICS unchanged and return NULL. */
6718 {
6720 {
6725 }
6728 }
6730 /* Compare two implicit conversion sequences according to the rules set out in
6731 [over.ics.rank]. Return values:
6733 1: ics1 is better than ics2
6734 -1: ics2 is better than ics1
6735 0: ics1 and ics2 are indistinguishable */
6737 static int
6739 {
6740 tree from_type1;
6741 tree from_type2;
6742 tree to_type1;
6743 tree to_type2;
6750 /* REF_BINDING is nonzero if the result of the conversion sequence
6751 is a reference type. In that case REF_CONV is the reference
6752 binding conversion. */
6756 /* Handle implicit object parameters. */
6760 /* Handle reference parameters. */
6764 /* List-initialization sequence L1 is a better conversion sequence than
6765 list-initialization sequence L2 if L1 converts to
6766 std::initializer_list<X> for some X and L2 does not. */
6772 /* [over.ics.rank]
6774 When comparing the basic forms of implicit conversion sequences (as
6775 defined in _over.best.ics_)
6777 --a standard conversion sequence (_over.ics.scs_) is a better
6778 conversion sequence than a user-defined conversion sequence
6779 or an ellipsis conversion sequence, and
6781 --a user-defined conversion sequence (_over.ics.user_) is a
6782 better conversion sequence than an ellipsis conversion sequence
6783 (_over.ics.ellipsis_). */
6793 {
6794 /* Both ICS are bad. We try to make a decision based on what would
6795 have happened if they'd been good. This is not an extension,
6796 we'll still give an error when we build up the call; this just
6797 helps us give a more helpful error message. */
6806 /* We couldn't make up our minds; try to figure it out below. */
6807 }
6810 /* Both conversions are ellipsis conversions or both are building a
6811 std::initializer_list. */
6814 /* User-defined conversion sequence U1 is a better conversion sequence
6815 than another user-defined conversion sequence U2 if they contain the
6816 same user-defined conversion operator or constructor and if the sec-
6817 ond standard conversion sequence of U1 is better than the second
6818 standard conversion sequence of U2. */
6821 {
6835 {
6838 }
6839 else
6840 {
6841 /* For ambiguous or aggregate conversions, use the target type as
6842 a proxy for the conversion function. */
6845 }
6847 /* We can just fall through here, after setting up
6848 FROM_TYPE1 and FROM_TYPE2. */
6851 }
6852 else
6853 {
6857 /* We're dealing with two standard conversion sequences.
6859 [over.ics.rank]
6861 Standard conversion sequence S1 is a better conversion
6862 sequence than standard conversion sequence S2 if
6864 --S1 is a proper subsequence of S2 (comparing the conversion
6865 sequences in the canonical form defined by _over.ics.scs_,
6866 excluding any Lvalue Transformation; the identity
6867 conversion sequence is considered to be a subsequence of
6868 any non-identity conversion sequence */
6879 }
6881 /* One sequence can only be a subsequence of the other if they start with
6882 the same type. They can start with different types when comparing the
6883 second standard conversion sequence in two user-defined conversion
6884 sequences. */
6886 {
6891 }
6893 /* [over.ics.rank]
6895 Or, if not that,
6897 --the rank of S1 is better than the rank of S2 (by the rules
6898 defined below):
6900 Standard conversion sequences are ordered by their ranks: an Exact
6901 Match is a better conversion than a Promotion, which is a better
6902 conversion than a Conversion.
6904 Two conversion sequences with the same rank are indistinguishable
6905 unless one of the following rules applies:
6907 --A conversion that does not a convert a pointer, pointer to member,
6908 or std::nullptr_t to bool is better than one that does.
6910 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
6911 so that we do not have to check it explicitly. */
6920 /* A conversion from scalar arithmetic type to complex is worse than a
6921 conversion between scalar arithmetic types. */
6928 {
6931 else
6933 }
6939 {
6944 }
6945 /* The rules for pointers to members A::* are just like the rules
6946 for pointers A*, except opposite: if B is derived from A then
6947 A::* converts to B::*, not vice versa. For that reason, we
6948 switch the from_ and to_ variables here. */
6955 {
6960 }
6965 {
6966 /* This was one of the pointer or pointer-like conversions.
6968 [over.ics.rank]
6970 --If class B is derived directly or indirectly from class A,
6971 conversion of B* to A* is better than conversion of B* to
6972 void*, and conversion of A* to void* is better than
6973 conversion of B* to void*. */
6976 {
6978 deref_from_type2))
6981 deref_from_type1))
6983 }
6986 {
6988 {
6990 {
6992 deref_to_type1))
6994 }
6995 /* We know that DEREF_TO_TYPE1 is `void' here. */
6997 deref_to_type2))
6999 }
7000 }
7003 {
7004 /* [over.ics.rank]
7006 --If class B is derived directly or indirectly from class A
7007 and class C is derived directly or indirectly from B,
7009 --conversion of C* to B* is better than conversion of C* to
7010 A*,
7012 --conversion of B* to A* is better than conversion of C* to
7013 A* */
7015 {
7017 deref_to_type2))
7020 deref_to_type1))
7022 }
7024 {
7026 deref_from_type1))
7029 deref_from_type2))
7031 }
7032 }
7033 }
7036 {
7039 /* [over.ics.rank]
7041 --binding of an expression of type C to a reference of type
7042 B& is better than binding an expression of type C to a
7043 reference of type A&
7045 --conversion of C to B is better than conversion of C to A, */
7048 {
7053 }
7054 }
7057 {
7060 /* [over.ics.rank]
7062 --binding of an expression of type B to a reference of type
7063 A& is better than binding an expression of type C to a
7064 reference of type A&,
7066 --conversion of B to A is better than conversion of C to A */
7069 {
7074 }
7075 }
7077 /* [over.ics.rank]
7079 --S1 and S2 differ only in their qualification conversion and yield
7080 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
7081 qualification signature of type T1 is a proper subset of the cv-
7082 qualification signature of type T2 */
7086 {
7090 }
7092 /* [over.ics.rank]
7094 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
7095 to an implicit object parameter, and either S1 binds an lvalue reference
7096 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
7097 reference to an rvalue and S2 binds an lvalue reference
7098 (C++0x draft standard, 13.3.3.2)
7100 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
7101 types to which the references refer are the same type except for
7102 top-level cv-qualifiers, and the type to which the reference
7103 initialized by S2 refers is more cv-qualified than the type to
7104 which the reference initialized by S1 refers */
7107 {
7111 {
7116 }
7121 }
7123 /* Neither conversion sequence is better than the other. */
7125 }
7127 /* The source type for this standard conversion sequence. */
7129 static tree
7131 {
7133 {
7138 }
7140 }
7142 /* Note a warning about preferring WINNER to LOSER. We do this by storing
7143 a pointer to LOSER and re-running joust to produce the warning if WINNER
7144 is actually used. */
7146 static void
7148 {
7154 }
7156 /* Compare two candidates for overloading as described in
7157 [over.match.best]. Return values:
7159 1: cand1 is better than cand2
7160 -1: cand2 is better than cand1
7161 0: cand1 and cand2 are indistinguishable */
7163 static int
7165 {
7171 /* Candidates that involve bad conversions are always worse than those
7172 that don't. */
7178 /* If we have two pseudo-candidates for conversions to the same type,
7179 or two candidates for the same function, arbitrarily pick one. */
7184 /* a viable function F1
7185 is defined to be a better function than another viable function F2 if
7186 for all arguments i, ICSi(F1) is not a worse conversion sequence than
7187 ICSi(F2), and then */
7189 /* for some argument j, ICSj(F1) is a better conversion sequence than
7190 ICSj(F2) */
7192 /* For comparing static and non-static member functions, we ignore
7193 the implicit object parameter of the non-static function. The
7194 standard says to pretend that the static function has an object
7195 parm, but that won't work with operator overloading. */
7198 {
7206 else
7207 {
7210 }
7211 }
7214 {
7220 {
7233 {
7240 else
7245 {
7249 }
7250 else
7252 }
7255 {
7258 }
7260 }
7261 }
7263 /* warn about confusing overload resolution for user-defined conversions,
7264 either between a constructor and a conversion op, or between two
7265 conversion ops. */
7269 {
7275 else
7278 /* We don't want to complain about `X::operator T1 ()'
7279 beating `X::operator T2 () const', when T2 is a no less
7280 cv-qualified version of T1. */
7283 {
7288 {
7291 }
7294 }
7295 else
7301 {
7308 {
7310 }
7311 }
7312 else
7314 }
7319 /* or, if not that,
7320 F1 is a non-template function and F2 is a template function
7321 specialization. */
7328 /* or, if not that,
7329 F1 and F2 are template functions and the function template for F1 is
7330 more specialized than the template for F2 according to the partial
7331 ordering rules. */
7334 {
7335 winner = more_specialized_fn
7338 /* [temp.func.order]: The presence of unused ellipsis and default
7339 arguments has no effect on the partial ordering of function
7340 templates. add_function_candidate() will not have
7341 counted the "this" argument for constructors. */
7345 }
7347 /* or, if not that,
7348 the context is an initialization by user-defined conversion (see
7349 _dcl.init_ and _over.match.user_) and the standard conversion
7350 sequence from the return type of F1 to the destination type (i.e.,
7351 the type of the entity being initialized) is a better conversion
7352 sequence than the standard conversion sequence from the return type
7353 of F2 to the destination type. */
7356 {
7360 }
7362 /* Check whether we can discard a builtin candidate, either because we
7363 have two identical ones or matching builtin and non-builtin candidates.
7365 (Pedantically in the latter case the builtin which matched the user
7366 function should not be added to the overload set, but we spot it here.
7368 [over.match.oper]
7369 ... the builtin candidates include ...
7370 - do not have the same parameter type list as any non-template
7371 non-member candidate. */
7375 {
7381 {
7383 /* Two built-in candidates; arbitrarily pick one. */
7386 /* cand1 is built-in; prefer cand2. */
7388 else
7389 /* cand2 is built-in; prefer cand1. */
7391 }
7392 }
7394 /* If the two function declarations represent the same function (this can
7395 happen with declarations in multiple scopes and arg-dependent lookup),
7396 arbitrarily choose one. But first make sure the default args we're
7397 using match. */
7400 {
7407 {
7408 /* Don't crash if the fn is variadic. */
7413 }
7421 {
7424 {
7426 {
7433 }
7434 else
7437 }
7440 }
7443 }
7445 tweak:
7447 /* Extension: If the worst conversion for one candidate is worse than the
7448 worst conversion for the other, take the first. */
7450 {
7455 {
7460 }
7466 {
7467 /* Don't choose a deleted function over ambiguity. */
7471 {
7473 "ISO C++ says that these are ambiguous, even "
7474 "though the worst conversion for the first is better than "
7478 }
7479 else
7482 }
7483 }
7487 }
7489 /* Given a list of candidates for overloading, find the best one, if any.
7490 This algorithm has a worst case of O(2n) (winner is last), and a best
7491 case of O(n/2) (totally ambiguous); much better than a sorting
7492 algorithm. */
7496 {
7501 /* Walk through the list once, comparing each current champ to the next
7502 candidate, knocking out a candidate or two with each comparison. */
7505 {
7509 else
7510 {
7512 {
7517 }
7518 else
7519 {
7522 }
7525 }
7526 }
7528 /* Make sure the champ is better than all the candidates it hasn't yet
7529 been compared to. */
7532 challenger != champ
7535 {
7539 }
7542 }
7544 /* Returns nonzero if things of type FROM can be converted to TO. */
7546 bool
7548 {
7550 }
7552 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
7554 bool
7556 {
7561 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7565 flags);
7568 /* Free all the conversions we allocated. */
7572 }
7574 /* Like can_convert_arg, but allows dubious conversions as well. */
7576 bool
7578 {
7582 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7584 /* Try to perform the conversion. */
7586 flags);
7587 /* Free all the conversions we allocated. */
7591 }
7593 /* Convert EXPR to TYPE. Return the converted expression.
7595 Note that we allow bad conversions here because by the time we get to
7596 this point we are committed to doing the conversion. If we end up
7597 doing a bad conversion, convert_like will complain. */
7599 tree
7601 {
7608 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7613 flags);
7616 {
7618 {
7619 /* If expr has unknown type, then it is an overloaded function.
7620 Call instantiate_type to get good error messages. */
7625 else
7627 }
7629 }
7631 {
7632 /* In a template, we are only concerned about determining the
7633 type of non-dependent expressions, so we do not have to
7634 perform the actual conversion. */
7637 }
7638 else
7641 /* Free all the conversions we allocated. */
7645 }
7647 tree
7649 {
7651 }
7653 /* Convert EXPR to TYPE (as a direct-initialization) if that is
7654 permitted. If the conversion is valid, the converted expression is
7655 returned. Otherwise, NULL_TREE is returned, except in the case
7656 that TYPE is a class type; in that case, an error is issued. If
7657 C_CAST_P is true, then this direction initialization is taking
7658 place as part of a static_cast being attempted as part of a C-style
7659 cast. */
7661 tree
7663 tree expr,
7665 tsubst_flags_t complain)
7666 {
7672 /* [dcl.init]
7674 If the destination type is a (possibly cv-qualified) class type:
7676 -- If the initialization is direct-initialization ...,
7677 constructors are considered. ... If no constructor applies, or
7678 the overload resolution is ambiguous, the initialization is
7679 ill-formed. */
7681 {
7687 }
7689 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7693 c_cast_p,
7694 LOOKUP_NORMAL);
7697 else
7700 c_cast_p,
7701 complain);
7703 /* Free all the conversions we allocated. */
7707 }
7709 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
7710 is being bound to a temporary. Create and return a new VAR_DECL
7711 with the indicated TYPE; this variable will store the value to
7712 which the reference is bound. */
7714 tree
7716 {
7717 tree var;
7719 /* Create the variable. */
7722 /* Register the variable. */
7724 {
7725 /* Namespace-scope or local static; give it a mangled name. */
7726 tree name;
7733 }
7734 else
7735 /* Create a new cleanup level if necessary. */
7739 }
7741 /* EXPR is the initializer for a variable DECL of reference or
7742 std::initializer_list type. Create, push and return a new VAR_DECL
7743 for the initializer so that it will live as long as DECL. Any
7744 cleanup for the new variable is returned through CLEANUP, and the
7745 code to initialize the new variable is returned through INITP. */
7747 tree
7749 {
7750 tree init;
7751 tree type;
7752 tree var;
7754 /* Create the temporary variable. */
7758 /* If the rvalue is the result of a function call it will be
7759 a TARGET_EXPR. If it is some other construct (such as a
7760 member access expression where the underlying object is
7761 itself the result of a function call), turn it into a
7762 TARGET_EXPR here. It is important that EXPR be a
7763 TARGET_EXPR below since otherwise the INIT_EXPR will
7764 attempt to make a bitwise copy of EXPR to initialize
7765 VAR. */
7768 /* Create the INIT_EXPR that will initialize the temporary
7769 variable. */
7772 {
7777 else
7780 /* We must be careful to destroy the temporary only
7781 after its initialization has taken place. If the
7782 initialization throws an exception, then the
7783 destructor should not be run. We cannot simply
7784 transform INIT into something like:
7786 (INIT, ({ CLEANUP_STMT; }))
7788 because emit_local_var always treats the
7789 initializer as a full-expression. Thus, the
7790 destructor would run too early; it would run at the
7791 end of initializing the reference variable, rather
7792 than at the end of the block enclosing the
7793 reference variable.
7795 The solution is to pass back a cleanup expression
7796 which the caller is responsible for attaching to
7797 the statement tree. */
7798 }
7799 else
7800 {
7804 static_aggregates);
7805 }
7809 }
7811 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
7812 initializing a variable of that TYPE. If DECL is non-NULL, it is
7813 the VAR_DECL being initialized with the EXPR. (In that case, the
7814 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
7815 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
7816 return, if *CLEANUP is no longer NULL, it will be an expression
7817 that should be pushed as a cleanup after the returned expression
7818 is used to initialize DECL.
7820 Return the converted expression. */
7822 tree
7824 tsubst_flags_t complain)
7825 {
7832 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7836 LOOKUP_NORMAL);
7838 {
7840 {
7847 else
7851 }
7853 }
7855 /* If DECL is non-NULL, then this special rule applies:
7857 [class.temporary]
7859 The temporary to which the reference is bound or the temporary
7860 that is the complete object to which the reference is bound
7861 persists for the lifetime of the reference.
7863 The temporaries created during the evaluation of the expression
7864 initializing the reference, except the temporary to which the
7865 reference is bound, are destroyed at the end of the
7866 full-expression in which they are created.
7868 In that case, we store the converted expression into a new
7869 VAR_DECL in a new scope.
7871 However, we want to be careful not to create temporaries when
7872 they are not required. For example, given:
7874 struct B {};
7875 struct D : public B {};
7876 D f();
7877 const B& b = f();
7879 there is no need to copy the return value from "f"; we can just
7880 extend its lifetime. Similarly, given:
7882 struct S {};
7883 struct T { operator S(); };
7884 T t;
7885 const S& s = t;
7887 we can extend the lifetime of the return value of the conversion
7888 operator. */
7891 {
7892 tree var;
7893 tree base_conv_type;
7895 /* Skip over the REF_BIND. */
7897 /* If the next conversion is a BASE_CONV, skip that too -- but
7898 remember that the conversion was required. */
7900 {
7903 }
7904 else
7906 /* Perform the remainder of the conversion. */
7912 tf_warning_or_error);
7915 else
7916 {
7918 {
7919 tree init;
7921 /* Use its address to initialize the reference variable. */
7929 }
7930 else
7931 /* Take the address of EXPR. */
7933 /* If a BASE_CONV was required, perform it now. */
7935 expr = (perform_implicit_conversion
7937 tf_warning_or_error));
7939 }
7940 }
7941 else
7942 /* Perform the conversion. */
7945 /* Free all the conversions we allocated. */
7949 }
7951 /* Returns true iff TYPE is some variant of std::initializer_list. */
7953 bool
7955 {
7956 /* Look through typedefs. */
7963 }
7965 /* Returns true iff DECL is a list constructor: i.e. a constructor which
7966 will accept an argument list of a single std::initializer_list<T>. */
7968 bool
7970 {
7972 tree arg;
7984 /* There are more non-defaulted parms. */
7988 }