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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)
134 #define convert_like(CONV, EXPR, COMPLAIN) \
135 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
138 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
139 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
162 static void add_builtin_candidates
165 static void add_builtin_candidate
169 static void build_builtin_candidate
174 tree);
204 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
205 NAME can take many forms... */
207 bool
209 {
210 /* Just accept something we've already complained about. */
219 {
225 else
227 }
228 else
229 {
230 /* In the case of:
232 template <class T> struct S { ~S(); };
233 int i;
234 i.~S();
236 NAME will be a class template. */
239 }
244 }
246 /* We want the address of a function or method. We avoid creating a
247 pointer-to-member function. */
249 tree
251 {
254 /* We have to do these by hand to avoid real pointer to member
255 functions. */
257 {
259 {
263 }
265 }
266 else
270 }
272 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
273 POINTER_TYPE to those. Note, pointer to member function types
274 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
275 two variants. build_call_a is the primitive taking an array of
276 arguments, while build_call_n is a wrapper that handles varargs. */
278 tree
280 {
283 else
284 {
294 }
295 }
297 tree
299 {
302 tree decl;
303 tree result_type;
304 tree fntype;
314 /* An rvalue has no cv-qualifiers. */
320 {
323 {
324 /* We invoke build_call directly for several library
325 functions. These may have been declared normally if
326 we're building libgcc, so we can't just check
327 DECL_ARTIFICIAL. */
332 }
333 }
334 else
337 /* We check both the decl and the type; a function may be known not to
338 throw without being declared throw(). */
352 /* Don't pass empty class objects by value. This is useful
353 for tags in STL, which are used to control overload resolution.
354 We don't need to handle other cases of copying empty classes. */
359 {
363 }
371 }
373 /* Build something of the form ptr->method (args)
374 or object.method (args). This can also build
375 calls to constructors, and find friends.
377 Member functions always take their class variable
378 as a pointer.
380 INSTANCE is a class instance.
382 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
384 PARMS help to figure out what that NAME really refers to.
386 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
387 down to the real instance type to use for access checking. We need this
388 information to get protected accesses correct.
390 FLAGS is the logical disjunction of zero or more LOOKUP_
391 flags. See cp-tree.h for more info.
393 If this is all OK, calls build_function_call with the resolved
394 member function.
396 This function must also handle being called to perform
397 initialization, promotion/coercion of arguments, and
398 instantiation of default parameters.
400 Note that NAME may refer to an instance variable name. If
401 `operator()()' is defined for the type of that field, then we return
402 that result. */
404 /* New overloading code. */
412 };
415 /* The FUNCTION_DECL that will be called if this candidate is
416 selected by overload resolution. */
417 tree fn;
418 /* If not NULL_TREE, the first argument to use when calling this
419 function. */
420 tree first_arg;
421 /* The rest of the arguments to use when calling this function. If
422 there are no further arguments this may be NULL or it may be an
423 empty vector. */
425 /* The implicit conversion sequences for each of the arguments to
426 FN. */
428 /* The number of implicit conversion sequences. */
430 /* If FN is a user-defined conversion, the standard conversion
431 sequence from the type returned by FN to the desired destination
432 type. */
435 /* If FN is a member function, the binfo indicating the path used to
436 qualify the name of FN at the call site. This path is used to
437 determine whether or not FN is accessible if it is selected by
438 overload resolution. The DECL_CONTEXT of FN will always be a
439 (possibly improper) base of this binfo. */
440 tree access_path;
441 /* If FN is a non-static member function, the binfo indicating the
442 subobject to which the `this' pointer should be converted if FN
443 is selected by overload resolution. The type pointed to the by
444 the `this' pointer must correspond to the most derived class
445 indicated by the CONVERSION_PATH. */
446 tree conversion_path;
447 tree template_decl;
448 tree explicit_targs;
451 };
453 /* Returns true iff T is a null pointer constant in the sense of
454 [conv.ptr]. */
456 bool
458 {
459 /* [conv.ptr]
461 A null pointer constant is an integral constant expression
462 (_expr.const_) rvalue of integer type that evaluates to zero or
463 an rvalue of type std::nullptr_t. */
469 {
473 }
475 }
477 /* Returns nonzero if PARMLIST consists of only default parms and/or
478 ellipsis. */
480 bool
482 {
488 }
490 /* Allocate N bytes of memory from the conversion obstack. The memory
491 is zeroed before being returned. */
495 {
498 {
501 }
505 }
507 /* Dynamically allocate a conversion. */
511 {
516 }
518 #ifdef ENABLE_CHECKING
520 /* Make sure that all memory on the conversion obstack has been
521 freed. */
523 void
525 {
529 }
533 /* Dynamically allocate an array of N conversions. */
537 {
539 }
543 {
547 /* Note that the caller is responsible for filling in t->cand for
548 user-defined conversions. */
554 {
570 }
576 }
578 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
579 specialization of std::initializer_list<T>, if such a conversion is
580 possible. */
584 {
590 tree val;
592 /* Within a list-initialization we can have more user-defined
593 conversions. */
595 /* But no narrowing conversions. */
599 {
600 conversion *sub
607 }
615 {
623 }
626 }
628 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
629 aggregate class, if such a conversion is possible. */
633 {
640 {
642 {
650 }
651 else
652 {
658 }
659 }
670 }
672 /* Build a representation of the identity conversion from EXPR to
673 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
677 {
685 }
687 /* Converting from EXPR to TYPE was ambiguous in the sense that there
688 were multiple user-defined conversions to accomplish the job.
689 Build a conversion that indicates that ambiguity. */
693 {
701 }
703 tree
705 {
709 }
711 /* Returns the standard conversion path (see [conv]) from type FROM to type
712 TO, if any. For proper handling of null pointer constants, you must
713 also pass the expression EXPR to convert from. If C_CAST_P is true,
714 this conversion is coming from a C-style cast. */
719 {
726 {
729 }
735 {
743 }
750 {
754 }
756 {
758 {
759 tree bitfield_type;
762 {
765 }
766 }
768 }
770 /* Allow conversion between `__complex__' data types. */
772 {
773 /* The standard conversion sequence to convert FROM to TO is
774 the standard conversion sequence to perform componentwise
775 conversion. */
780 {
783 }
784 else
788 }
793 /* [conv.ptr]
794 A null pointer constant can be converted to a pointer type; ... A
795 null pointer constant of integral type can be converted to an
796 rvalue of type std::nullptr_t. */
803 {
804 /* For backwards brain damage compatibility, allow interconversion of
805 pointers and integers with a pedwarn. */
808 }
810 {
811 /* For backwards brain damage compatibility, allow interconversion of
812 enums and integers with a pedwarn. */
815 }
818 {
819 tree to_pointee;
820 tree from_pointee;
825 ;
829 {
830 from = build_pointer_type
834 }
836 {
841 && (same_type_ignoring_top_level_qualifiers_p
844 {
848 }
851 }
854 /* [conv.ptr]
856 An rvalue of type "pointer to cv D," where D is a
857 class type, can be converted to an rvalue of type
858 "pointer to cv B," where B is a base class (clause
859 _class.derived_) of D. If B is an inaccessible
860 (clause _class.access_) or ambiguous
861 (_class.member.lookup_) base class of D, a program
862 that necessitates this conversion is ill-formed.
863 Therefore, we use DERIVED_FROM_P, and do not check
864 access or uniqueness. */
866 {
867 from =
873 }
876 {
879 }
880 else
881 {
884 }
889 /* In a C-style cast, we ignore CV-qualification because we
890 are allowed to perform a static_cast followed by a
891 const_cast. */
896 /* converting from string constant to char *. */
899 {
902 }
903 else
907 }
909 {
926 }
928 {
929 /* [conv.bool]
931 An rvalue of arithmetic, unscoped enumeration, pointer, or
932 pointer to member type can be converted to an rvalue of type
933 bool. ... An rvalue of type std::nullptr_t can be converted
934 to an rvalue of type bool; */
940 {
949 }
952 }
953 /* We don't check for ENUMERAL_TYPE here because there are no standard
954 conversions to enum type. */
955 /* As an extension, allow conversion to complex type. */
957 {
963 /* Give this a better rank if it's a promotion. */
967 }
973 {
977 /* The derived-to-base conversion indicates the initialization
978 of a parameter with base type from an object of a derived
979 type. A temporary object is created to hold the result of
980 the conversion unless we're binding directly to a reference. */
982 }
983 else
990 }
992 /* Returns nonzero if T1 is reference-related to T2. */
994 bool
996 {
1000 /* [dcl.init.ref]
1002 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1003 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1004 of T2. */
1008 }
1010 /* Returns nonzero if T1 is reference-compatible with T2. */
1012 static bool
1014 {
1015 /* [dcl.init.ref]
1017 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1018 reference-related to T2 and cv1 is the same cv-qualification as,
1019 or greater cv-qualification than, cv2. */
1022 }
1024 /* Determine whether or not the EXPR (of class type S) can be
1025 converted to T as in [over.match.ref]. */
1029 {
1030 tree conversions;
1031 tree first_arg;
1033 tree t;
1042 /* [over.match.ref]
1044 Assuming that "cv1 T" is the underlying type of the reference
1045 being initialized, and "cv S" is the type of the initializer
1046 expression, with S a class type, the candidate functions are
1047 selected as follows:
1049 --The conversion functions of S and its base classes are
1050 considered. Those that are not hidden within S and yield type
1051 "reference to cv2 T2", where "cv1 T" is reference-compatible
1052 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
1054 The argument list has one argument, which is the initializer
1055 expression. */
1059 /* Conceptually, we should take the address of EXPR and put it in
1060 the argument list. Unfortunately, however, that can result in
1061 error messages, which we should not issue now because we are just
1062 trying to find a conversion operator. Therefore, we use NULL,
1063 cast to the appropriate type. */
1068 /* We're performing a user-defined conversion to a desired type, so set
1069 this for the benefit of add_candidates. */
1073 {
1084 {
1085 /* Now, see if the conversion function really returns
1086 an lvalue of the appropriate type. From the
1087 point of view of unification, simply returning an
1088 rvalue of the right type is good enough. */
1093 {
1095 }
1096 else
1097 {
1099 /* Build a standard conversion sequence indicating the
1100 binding from the reference type returned by the
1101 function to the desired REFERENCE_TYPE. */
1102 identity_conv
1105 NULL_TREE);
1106 cand->second_conv
1107 = (direct_reference_binding
1114 /* Don't allow binding of lvalues to rvalue references. */
1118 }
1119 }
1120 }
1123 /* If none of the conversion functions worked out, let our caller
1124 know. */
1132 /* Now that we know that this is the function we're going to use fix
1133 the dummy first argument. */
1138 /* Build a user-defined conversion sequence representing the
1139 conversion. */
1148 /* Merge it with the standard conversion sequence from the
1149 conversion function's return type to the desired type. */
1153 }
1155 /* A reference of the indicated TYPE is being bound directly to the
1156 expression represented by the implicit conversion sequence CONV.
1157 Return a conversion sequence for this binding. */
1161 {
1162 tree t;
1169 /* [over.ics.rank]
1171 When a parameter of reference type binds directly
1172 (_dcl.init.ref_) to an argument expression, the implicit
1173 conversion sequence is the identity conversion, unless the
1174 argument expression has a type that is a derived class of the
1175 parameter type, in which case the implicit conversion sequence is
1176 a derived-to-base Conversion.
1178 If the parameter binds directly to the result of applying a
1179 conversion function to the argument expression, the implicit
1180 conversion sequence is a user-defined conversion sequence
1181 (_over.ics.user_), with the second standard conversion sequence
1182 either an identity conversion or, if the conversion function
1183 returns an entity of a type that is a derived class of the
1184 parameter type, a derived-to-base conversion. */
1186 {
1187 /* Represent the derived-to-base conversion. */
1189 /* We will actually be binding to the base-class subobject in
1190 the derived class, so we mark this conversion appropriately.
1191 That way, convert_like knows not to generate a temporary. */
1193 }
1195 }
1197 /* Returns the conversion path from type FROM to reference type TO for
1198 purposes of reference binding. For lvalue binding, either pass a
1199 reference type to FROM or an lvalue expression to EXPR. If the
1200 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1201 the conversion returned. If C_CAST_P is true, this
1202 conversion is coming from a C-style cast. */
1206 {
1210 tree tfrom;
1216 {
1221 }
1224 {
1225 /* Anything with reference type is an lvalue. */
1228 }
1231 {
1234 flags);
1237 {
1242 }
1243 }
1252 /* Figure out whether or not the types are reference-related and
1253 reference compatible. We have do do this after stripping
1254 references from FROM. */
1256 /* If this is a C cast, first convert to an appropriately qualified
1257 type, so that we can later do a const_cast to the desired type. */
1263 /* Directly bind reference when target expression's type is compatible with
1264 the reference and expression is an lvalue. In DR391, the wording in
1265 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1266 const and rvalue references to rvalues of compatible class type.
1267 We should also do direct bindings for non-class "rvalues" derived from
1268 rvalue references. */
1270 && (is_lvalue
1275 {
1276 /* [dcl.init.ref]
1278 If the initializer expression
1280 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1281 is reference-compatible with "cv2 T2,"
1283 the reference is bound directly to the initializer expression
1284 lvalue.
1286 [...]
1287 If the initializer expression is an rvalue, with T2 a class type,
1288 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1289 is bound to the object represented by the rvalue or to a sub-object
1290 within that object. */
1296 /* The top-level caller requested that we pretend that the lvalue
1297 be treated as an rvalue. */
1299 else
1300 conv->rvaluedness_matches_p
1305 /* For the purposes of overload resolution, we ignore the fact
1306 this expression is a bitfield or packed field. (In particular,
1307 [over.ics.ref] says specifically that a function with a
1308 non-const reference parameter is viable even if the
1309 argument is a bitfield.)
1311 However, when we actually call the function we must create
1312 a temporary to which to bind the reference. If the
1313 reference is volatile, or isn't const, then we cannot make
1314 a temporary, so we just issue an error when the conversion
1315 actually occurs. */
1318 /* Don't allow binding of lvalues to rvalue references. */
1324 }
1325 /* [class.conv.fct] A conversion function is never used to convert a
1326 (possibly cv-qualified) object to the (possibly cv-qualified) same
1327 object type (or a reference to it), to a (possibly cv-qualified) base
1328 class of that type (or a reference to it).... */
1331 {
1332 /* [dcl.init.ref]
1334 If the initializer expression
1336 -- has a class type (i.e., T2 is a class type) can be
1337 implicitly converted to an lvalue of type "cv3 T3," where
1338 "cv1 T1" is reference-compatible with "cv3 T3". (this
1339 conversion is selected by enumerating the applicable
1340 conversion functions (_over.match.ref_) and choosing the
1341 best one through overload resolution. (_over.match_).
1343 the reference is bound to the lvalue result of the conversion
1344 in the second case. */
1348 }
1350 /* From this point on, we conceptually need temporaries, even if we
1351 elide them. Only the cases above are "direct bindings". */
1355 /* [over.ics.rank]
1357 When a parameter of reference type is not bound directly to an
1358 argument expression, the conversion sequence is the one required
1359 to convert the argument expression to the underlying type of the
1360 reference according to _over.best.ics_. Conceptually, this
1361 conversion sequence corresponds to copy-initializing a temporary
1362 of the underlying type with the argument expression. Any
1363 difference in top-level cv-qualification is subsumed by the
1364 initialization itself and does not constitute a conversion. */
1366 /* [dcl.init.ref]
1368 Otherwise, the reference shall be to a non-volatile const type.
1370 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1374 /* [dcl.init.ref]
1376 Otherwise, a temporary of type "cv1 T1" is created and
1377 initialized from the initializer expression using the rules for a
1378 non-reference copy initialization. If T1 is reference-related to
1379 T2, cv1 must be the same cv-qualification as, or greater
1380 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1384 /* We're generating a temporary now, but don't bind any more in the
1385 conversion (specifically, don't slice the temporary returned by a
1386 conversion operator). */
1389 /* Temporaries are copy-initialized, except for this hack to allow
1390 explicit conversion ops to the copy ctor. See also
1391 add_function_candidate. */
1397 flags);
1402 /* This reference binding, unlike those above, requires the
1403 creation of a temporary. */
1408 }
1410 /* Returns the implicit conversion sequence (see [over.ics]) from type
1411 FROM to type TO. The optional expression EXPR may affect the
1412 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1413 true, this conversion is coming from a C-style cast. */
1418 {
1427 else
1434 {
1438 /* Allow conversion from an initializer-list with one element to a
1439 scalar type. */
1441 {
1443 tree elt;
1449 else
1455 {
1458 /* Too many levels of braces, i.e. '{{1}}'. */
1461 }
1462 }
1463 }
1469 {
1483 /* We used to try to bind a reference to a temporary here, but that
1484 is now handled after the recursive call to this function at the end
1485 of reference_binding. */
1487 }
1490 }
1492 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1493 functions. ARGS will not be changed until a single candidate is
1494 selected. */
1502 {
1518 }
1520 /* Create an overload candidate for the function or method FN called
1521 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1522 FLAGS is passed on to implicit_conversion.
1524 This does not change ARGS.
1526 CTYPE, if non-NULL, is the type we want to pretend this function
1527 comes from for purposes of overload resolution. */
1534 {
1538 tree parmnode;
1543 /* At this point we should not see any functions which haven't been
1544 explicitly declared, except for friend functions which will have
1545 been found using argument dependent lookup. */
1548 /* The `this', `in_chrg' and VTT arguments to constructors are not
1549 considered in overload resolution. */
1551 {
1555 {
1558 }
1559 }
1560 else
1566 /* 13.3.2 - Viable functions [over.match.viable]
1567 First, to be a viable function, a candidate function shall have enough
1568 parameters to agree in number with the arguments in the list.
1570 We need to check this first; otherwise, checking the ICSes might cause
1571 us to produce an ill-formed template instantiation. */
1575 {
1579 }
1584 /* Make sure there are default args for the rest of the parms. */
1591 /* Second, for F to be a viable function, there shall exist for each
1592 argument an implicit conversion sequence that converts that argument
1593 to the corresponding parameter of F. */
1598 {
1608 else
1617 {
1621 /* The type of the implicit object parameter ('this') for
1622 overload resolution is not always the same as for the
1623 function itself; conversion functions are considered to
1624 be members of the class being converted, and functions
1625 introduced by a using-declaration are considered to be
1626 members of the class that uses them.
1628 Since build_over_call ignores the ICS for the `this'
1629 parameter, we can just change the parm type. */
1631 {
1632 parmtype = cp_build_qualified_type
1635 }
1639 {
1640 /* Hack: Direct-initialize copy parm (i.e. suppress
1641 LOOKUP_ONLYCONVERTING) to make explicit conversion ops
1642 work. See also reference_binding. */
1646 }
1647 else
1652 }
1653 else
1654 {
1657 }
1664 {
1667 }
1674 }
1676 out:
1679 }
1681 /* Create an overload candidate for the conversion function FN which will
1682 be invoked for expression OBJ, producing a pointer-to-function which
1683 will in turn be called with the argument list FIRST_ARG/ARGLIST,
1684 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
1685 passed on to implicit_conversion.
1687 Actually, we don't really care about FN; we care about the type it
1688 converts to. There may be multiple conversion functions that will
1689 convert to that type, and we rely on build_user_type_conversion_1 to
1690 choose the best one; so when we create our candidate, we record the type
1691 instead of the function. */
1697 {
1713 /* Don't bother looking up the same type twice. */
1718 {
1726 else
1733 flags);
1739 else
1740 {
1743 }
1757 }
1767 }
1769 static void
1773 {
1786 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
1787 conversion ops are allowed. We handle that here by just checking for
1788 boolean_type_node because other operators don't ask for it. COND_EXPR
1789 also does contextual conversion to bool for the first operand, but we
1790 handle that in build_conditional_expr, and type1 here is operand 2. */
1795 {
1802 {
1804 /* We need something for printing the candidate. */
1806 }
1810 }
1812 /* For COND_EXPR we rearranged the arguments; undo that now. */
1814 {
1821 else
1823 }
1829 viable);
1830 }
1832 static bool
1834 {
1836 }
1838 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1840 static bool
1842 {
1843 /* [over.built]
1845 In this section, the term promoted integral type is used to refer
1846 to those integral types which are preserved by integral promotion
1847 (including e.g. int and long but excluding e.g. char).
1848 Similarly, the term promoted arithmetic type refers to promoted
1849 integral types plus floating types. */
1853 }
1855 /* Create any builtin operator overload candidates for the operator in
1856 question given the converted operand types TYPE1 and TYPE2. The other
1857 args are passed through from add_builtin_candidates to
1858 build_builtin_candidate.
1860 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1861 If CODE is requires candidates operands of the same type of the kind
1862 of which TYPE1 and TYPE2 are, we add both candidates
1863 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1865 static void
1869 {
1871 {
1879 }
1882 {
1884 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1885 and VQ is either volatile or empty, there exist candidate operator
1886 functions of the form
1887 VQ T& operator++(VQ T&);
1888 T operator++(VQ T&, int);
1889 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1890 type other than bool, and VQ is either volatile or empty, there exist
1891 candidate operator functions of the form
1892 VQ T& operator--(VQ T&);
1893 T operator--(VQ T&, int);
1894 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1895 complete object type, and VQ is either volatile or empty, there exist
1896 candidate operator functions of the form
1897 T*VQ& operator++(T*VQ&);
1898 T*VQ& operator--(T*VQ&);
1899 T* operator++(T*VQ&, int);
1900 T* operator--(T*VQ&, int); */
1909 {
1912 }
1915 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1916 exist candidate operator functions of the form
1918 T& operator*(T*);
1920 8 For every function type T, there exist candidate operator functions of
1921 the form
1922 T& operator*(T*); */
1931 /* 9 For every type T, there exist candidate operator functions of the form
1932 T* operator+(T*);
1934 10For every promoted arithmetic type T, there exist candidate operator
1935 functions of the form
1936 T operator+(T);
1937 T operator-(T); */
1947 /* 11For every promoted integral type T, there exist candidate operator
1948 functions of the form
1949 T operator~(T); */
1956 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1957 is the same type as C2 or is a derived class of C2, T is a complete
1958 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1959 there exist candidate operator functions of the form
1960 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1961 where CV12 is the union of CV1 and CV2. */
1966 {
1974 }
1977 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1978 didate operator functions of the form
1979 LR operator*(L, R);
1980 LR operator/(L, R);
1981 LR operator+(L, R);
1982 LR operator-(L, R);
1983 bool operator<(L, R);
1984 bool operator>(L, R);
1985 bool operator<=(L, R);
1986 bool operator>=(L, R);
1987 bool operator==(L, R);
1988 bool operator!=(L, R);
1989 where LR is the result of the usual arithmetic conversions between
1990 types L and R.
1992 14For every pair of types T and I, where T is a cv-qualified or cv-
1993 unqualified complete object type and I is a promoted integral type,
1994 there exist candidate operator functions of the form
1995 T* operator+(T*, I);
1996 T& operator[](T*, I);
1997 T* operator-(T*, I);
1998 T* operator+(I, T*);
1999 T& operator[](I, T*);
2001 15For every T, where T is a pointer to complete object type, there exist
2002 candidate operator functions of the form112)
2003 ptrdiff_t operator-(T, T);
2005 16For every pointer or enumeration type T, there exist candidate operator
2006 functions of the form
2007 bool operator<(T, T);
2008 bool operator>(T, T);
2009 bool operator<=(T, T);
2010 bool operator>=(T, T);
2011 bool operator==(T, T);
2012 bool operator!=(T, T);
2014 17For every pointer to member type T, there exist candidate operator
2015 functions of the form
2016 bool operator==(T, T);
2017 bool operator!=(T, T); */
2024 {
2027 }
2040 {
2043 }
2045 {
2048 }
2049 /* Fall through. */
2066 {
2069 }
2073 {
2076 }
2084 {
2087 }
2089 {
2092 }
2095 /* 18For every pair of promoted integral types L and R, there exist candi-
2096 date operator functions of the form
2097 LR operator%(L, R);
2098 LR operator&(L, R);
2099 LR operator^(L, R);
2100 LR operator|(L, R);
2101 L operator<<(L, R);
2102 L operator>>(L, R);
2103 where LR is the result of the usual arithmetic conversions between
2104 types L and R. */
2112 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2116 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2117 type, VQ is either volatile or empty, and R is a promoted arithmetic
2118 type, there exist candidate operator functions of the form
2119 VQ L& operator=(VQ L&, R);
2120 VQ L& operator*=(VQ L&, R);
2121 VQ L& operator/=(VQ L&, R);
2122 VQ L& operator+=(VQ L&, R);
2123 VQ L& operator-=(VQ L&, R);
2125 20For every pair T, VQ), where T is any type and VQ is either volatile
2126 or empty, there exist candidate operator functions of the form
2127 T*VQ& operator=(T*VQ&, T*);
2129 21For every pair T, VQ), where T is a pointer to member type and VQ is
2130 either volatile or empty, there exist candidate operator functions of
2131 the form
2132 VQ T& operator=(VQ T&, T);
2134 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2135 unqualified complete object type, VQ is either volatile or empty, and
2136 I is a promoted integral type, there exist candidate operator func-
2137 tions of the form
2138 T*VQ& operator+=(T*VQ&, I);
2139 T*VQ& operator-=(T*VQ&, I);
2141 23For every triple L, VQ, R), where L is an integral or enumeration
2142 type, VQ is either volatile or empty, and R is a promoted integral
2143 type, there exist candidate operator functions of the form
2145 VQ L& operator%=(VQ L&, R);
2146 VQ L& operator<<=(VQ L&, R);
2147 VQ L& operator>>=(VQ L&, R);
2148 VQ L& operator&=(VQ L&, R);
2149 VQ L& operator^=(VQ L&, R);
2150 VQ L& operator|=(VQ L&, R); */
2154 {
2158 {
2161 }
2174 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2187 {
2190 }
2195 }
2200 /* [over.built]
2202 For every pair of promoted arithmetic types L and R, there
2203 exist candidate operator functions of the form
2205 LR operator?(bool, L, R);
2207 where LR is the result of the usual arithmetic conversions
2208 between types L and R.
2210 For every type T, where T is a pointer or pointer-to-member
2211 type, there exist candidate operator functions of the form T
2212 operator?(bool, T, T); */
2216 /* That's OK. */
2219 /* Otherwise, the types should be pointers. */
2224 /* We don't check that the two types are the same; the logic
2225 below will actually create two candidates; one in which both
2226 parameter types are TYPE1, and one in which both parameter
2227 types are TYPE2. */
2232 }
2234 /* If we're dealing with two pointer types or two enumeral types,
2235 we need candidates for both of them. */
2244 {
2245 build_builtin_candidate
2247 build_builtin_candidate
2250 }
2252 build_builtin_candidate
2254 }
2256 tree
2258 {
2266 }
2268 /* There are three conditions of builtin candidates:
2270 1) bool-taking candidates. These are the same regardless of the input.
2271 2) pointer-pair taking candidates. These are generated for each type
2272 one of the input types converts to.
2273 3) arithmetic candidates. According to the standard, we should generate
2274 all of these, but I'm trying not to...
2276 Here we generate a superset of the possible candidates for this particular
2277 case. That is a subset of the full set the standard defines, plus some
2278 other cases which the standard disallows. add_builtin_candidate will
2279 filter out the invalid set. */
2281 static void
2285 {
2289 /* TYPES[i] is the set of possible builtin-operator parameter types
2290 we will consider for the Ith argument. These are represented as
2291 a TREE_LIST; the TREE_VALUE of each node is the potential
2292 parameter type. */
2296 {
2299 else
2301 }
2304 {
2305 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2306 and VQ is either volatile or empty, there exist candidate operator
2307 functions of the form
2308 VQ T& operator++(VQ T&); */
2318 /* 24There also exist candidate operator functions of the form
2319 bool operator!(bool);
2320 bool operator&&(bool, bool);
2321 bool operator||(bool, bool); */
2324 build_builtin_candidate
2331 build_builtin_candidate
2349 /* Fall through. */
2353 }
2358 {
2360 ;
2362 {
2363 tree convs;
2372 {
2379 }
2385 {
2398 {
2404 }
2408 }
2409 }
2410 else
2411 {
2417 {
2423 }
2425 }
2426 }
2428 /* Run through the possible parameter types of both arguments,
2429 creating candidates with those parameter types. */
2431 {
2434 add_builtin_candidate
2437 else
2438 add_builtin_candidate
2441 }
2442 }
2445 /* If TMPL can be successfully instantiated as indicated by
2446 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2448 TMPL is the template. EXPLICIT_TARGS are any explicit template
2449 arguments. ARGLIST is the arguments provided at the call-site.
2450 This does not change ARGLIST. The RETURN_TYPE is the desired type
2451 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2452 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2453 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2461 {
2471 tree arg;
2474 tree fn;
2476 /* We don't do deduction on the in-charge parameter, the VTT
2477 parameter or 'this'. */
2479 {
2482 else
2484 }
2489 {
2492 else
2494 }
2504 {
2507 }
2511 {
2514 }
2518 args_without_in_chrg,
2519 nargs_without_in_chrg,
2529 /* In [class.copy]:
2531 A member function template is never instantiated to perform the
2532 copy of a class object to an object of its class type.
2534 It's a little unclear what this means; the standard explicitly
2535 does allow a template to be used to copy a class. For example,
2536 in:
2538 struct A {
2539 A(A&);
2540 template <class T> A(const T&);
2541 };
2542 const A f ();
2543 void g () { A a (f ()); }
2545 the member template will be used to make the copy. The section
2546 quoted above appears in the paragraph that forbids constructors
2547 whose only parameter is (a possibly cv-qualified variant of) the
2548 class type, and a logical interpretation is that the intent was
2549 to forbid the instantiation of member templates which would then
2550 have that form. */
2552 {
2555 ctype))
2557 }
2560 /* Aha, this is a conversion function. */
2563 else
2568 /* This situation can occur if a member template of a template
2569 class is specialized. Then, instantiate_template might return
2570 an instantiation of the specialization, in which case the
2571 DECL_TI_TEMPLATE field will point at the original
2572 specialization. For example:
2574 template <class T> struct S { template <class U> void f(U);
2575 template <> void f(int) {}; };
2576 S<double> sd;
2577 sd.f(3);
2579 Here, TMPL will be template <class U> S<double>::f(U).
2580 And, instantiate template will give us the specialization
2581 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2582 for this will point at template <class T> template <> S<T>::f(int),
2583 so that we can find the definition. For the purposes of
2584 overload resolution, however, we want the original TMPL. */
2586 else
2591 fail:
2594 }
2602 unification_kind_t strict)
2603 {
2604 return
2609 }
2617 tree conversion_path)
2618 {
2619 return
2623 }
2625 /* The CANDS are the set of candidates that were considered for
2626 overload resolution. Return the set of viable candidates, or CANDS
2627 if none are viable. If any of the candidates were viable, set
2628 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
2629 considered viable only if it is strictly viable. */
2635 {
2646 {
2649 {
2655 }
2656 else
2658 }
2661 }
2663 static bool
2665 {
2670 }
2672 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2673 words, it is about to become the "this" pointer for a member
2674 function call. Take the address of the object. */
2676 static tree
2678 {
2679 /* In a template, we are only concerned about the type of the
2680 expression, so we can take a shortcut. */
2685 }
2687 /* Returns true iff functions are equivalent. Equivalent functions are
2688 not '==' only if one is a function-local extern function or if
2689 both are extern "C". */
2693 {
2702 }
2704 /* Print information about one overload candidate CANDIDATE. MSGSTR
2705 is the text to print before the candidate itself.
2707 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2708 to have been run through gettext by the caller. This wart makes
2709 life simpler in print_z_candidates and for the translators. */
2711 static void
2713 {
2715 {
2725 else
2728 }
2735 else
2737 }
2739 static void
2741 {
2750 /* Remove non-viable deleted candidates. */
2753 {
2758 else
2760 }
2761 /* ...if there are any non-deleted ones. */
2765 /* There may be duplicates in the set of candidates. We put off
2766 checking this condition as long as possible, since we have no way
2767 to eliminate duplicates from a set of functions in less than n^2
2768 time. Now we are about to emit an error message, so it is more
2769 permissible to go slowly. */
2771 {
2773 /* Skip builtin candidates and conversion functions. */
2778 {
2782 else
2784 }
2785 }
2790 {
2793 }
2795 }
2797 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2798 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2799 the result of the conversion function to convert it to the final
2800 desired type. Merge the two sequences into a single sequence,
2801 and return the merged sequence. */
2805 {
2810 /* Find the end of the second conversion sequence. */
2815 /* Replace the identity conversion with the user conversion
2816 sequence. */
2819 /* The entire sequence is a user-conversion sequence. */
2823 }
2825 /* Handle overload resolution for initializing an object of class type from
2826 an initializer list. First we look for a suitable constructor that
2827 takes a std::initializer_list; if we don't find one, we then look for a
2828 non-list constructor.
2830 Parameters are as for add_candidates, except that the arguments are in
2831 the form of a CONSTRUCTOR (the initializer list) rather than a VEC, and
2832 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
2834 static void
2841 {
2846 /* For list-initialization we consider explicit constructors, but
2847 give an error if one is selected. */
2849 /* And we don't allow narrowing conversions. We also use this flag to
2850 avoid the copy constructor call for copy-list-initialization. */
2853 /* Always use the default constructor if the list is empty (DR 990). */
2856 ;
2857 /* If the class has a list ctor, try passing the list as a single
2858 argument first, but only consider list ctors. */
2860 {
2868 }
2872 /* We aren't looking for list-ctors anymore. */
2874 /* We allow more user-defined conversions within an init-list. */
2876 /* But not for the copy ctor. */
2882 }
2884 /* Returns the best overload candidate to perform the requested
2885 conversion. This function is used for three the overloading situations
2886 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2887 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2888 per [dcl.init.ref], so we ignore temporary bindings. */
2892 {
2903 /* We represent conversion within a hierarchy using RVALUE_CONV and
2904 BASE_CONV, as specified by [over.best.ics]; these become plain
2905 constructor calls, as specified in [dcl.init]. */
2913 {
2918 {
2919 /* [class.conv.fct] A conversion function is never used to
2920 convert a (possibly cv-qualified) object to the (possibly
2921 cv-qualified) same object type (or a reference to it), to a
2922 (possibly cv-qualified) base class of that type (or a
2923 reference to it)... */
2924 }
2925 else
2928 }
2935 /* It's OK to bind a temporary for converting constructor arguments, but
2936 not in converting the return value of a conversion operator. */
2941 {
2947 /* We should never try to call the abstract or base constructor
2948 from here. */
2953 {
2954 /* List-initialization. */
2958 }
2959 else
2960 {
2965 }
2968 {
2971 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
2972 set, then this is copy-initialization. In that case, "The
2973 result of the call is then used to direct-initialize the
2974 object that is the destination of the copy-initialization."
2975 [dcl.init]
2977 We represent this in the conversion sequence with an
2978 rvalue conversion, which means a constructor call. */
2981 cand->second_conv
2983 }
2984 }
2990 {
2994 /* If we are called to convert to a reference type, we are trying to
2995 find an lvalue binding, so don't even consider temporaries. If
2996 we don't find an lvalue binding, the caller will try again to
2997 look for a temporary binding. */
3008 {
3009 conversion *ics
3015 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3016 copy-initialization. In that case, "The result of the
3017 call is then used to direct-initialize the object that is
3018 the destination of the copy-initialization." [dcl.init]
3020 We represent this in the conversion sequence with an
3021 rvalue conversion, which means a constructor call. But
3022 don't add a second rvalue conversion if there's already
3023 one there. Which there really shouldn't be, but it's
3024 harmless since we'd add it here anyway. */
3035 }
3036 }
3044 {
3046 {
3050 }
3057 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3058 ambiguous conversion is no worse than another user-defined
3059 conversion. */
3062 }
3064 /* Build the user conversion sequence. */
3065 conv = build_conv
3072 /* Remember that this was a list-initialization. */
3076 /* Combine it with the second conversion sequence. */
3084 }
3086 tree
3088 {
3093 {
3098 }
3100 }
3102 /* Do any initial processing on the arguments to a function call. */
3106 {
3108 tree arg;
3111 {
3115 {
3118 }
3121 }
3123 }
3125 /* Perform overload resolution on FN, which is called with the ARGS.
3127 Return the candidate function selected by overload resolution, or
3128 NULL if the event that overload resolution failed. In the case
3129 that overload resolution fails, *CANDIDATES will be the set of
3130 candidates considered, and ANY_VIABLE_P will be set to true or
3131 false to indicate whether or not any of the candidates were
3132 viable.
3134 The ARGS should already have gone through RESOLVE_ARGS before this
3135 function is called. */
3142 {
3150 /* Check FN. */
3157 {
3161 }
3163 /* Add the various candidate functions. */
3168 LOOKUP_NORMAL,
3169 candidates);
3177 }
3179 /* Return an expression for a call to FN (a namespace-scope function,
3180 or a static member function) with the ARGS. This may change
3181 ARGS. */
3183 tree
3185 tsubst_flags_t complain)
3186 {
3190 tree result;
3193 {
3197 }
3199 /* If this function was found without using argument dependent
3200 lookup, then we want to ignore any undeclared friend
3201 functions. */
3203 {
3208 {
3214 }
3215 }
3217 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3223 {
3225 {
3234 else
3239 }
3241 }
3242 else
3245 /* Free all the conversions we allocated. */
3249 }
3251 /* Build a call to a global operator new. FNNAME is the name of the
3252 operator (either "operator new" or "operator new[]") and ARGS are
3253 the arguments provided. This may change ARGS. *SIZE points to the
3254 total number of bytes required by the allocation, and is updated if
3255 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
3256 be used. If this function determines that no cookie should be
3257 used, after all, *COOKIE_SIZE is set to NULL_TREE. If FN is
3258 non-NULL, it will be set, upon return, to the allocation function
3259 called. */
3261 tree
3265 {
3266 tree fns;
3278 /* Based on:
3280 [expr.new]
3282 If this lookup fails to find the name, or if the allocated type
3283 is not a class type, the allocation function's name is looked
3284 up in the global scope.
3286 we disregard block-scope declarations of "operator new". */
3289 /* Figure out what function is being called. */
3292 /* If no suitable function could be found, issue an error message
3293 and give up. */
3295 {
3299 else
3305 }
3307 /* If a cookie is required, add some extra space. Whether
3308 or not a cookie is required cannot be determined until
3309 after we know which function was called. */
3311 {
3314 {
3315 /* In G++ 3.2, the check was implemented incorrectly; it
3316 looked at the placement expression, rather than the
3317 type of the function. */
3320 ptr_type_node))
3322 }
3323 else
3324 {
3325 tree arg_types;
3328 /* Skip the size_t parameter. */
3330 /* Check the remaining parameters (if any). */
3334 ptr_type_node))
3336 }
3337 /* If we need a cookie, adjust the number of bytes allocated. */
3339 {
3340 /* Update the total size. */
3342 /* Update the argument list to reflect the adjusted size. */
3344 }
3345 else
3347 }
3349 /* Tell our caller which function we decided to call. */
3353 /* Build the CALL_EXPR. */
3355 }
3357 /* Build a new call to operator(). This may change ARGS. */
3359 tree
3361 {
3375 {
3377 /* It's no good looking for an overloaded operator() on a
3378 pointer-to-member-function. */
3379 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3381 }
3384 {
3388 }
3389 else
3393 {
3397 }
3399 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3403 {
3411 }
3416 {
3428 {
3435 add_template_conv_candidate
3439 else
3443 }
3444 }
3448 {
3450 {
3454 }
3456 }
3457 else
3458 {
3461 {
3463 {
3467 }
3469 }
3470 /* Since cand->fn will be a type, not a function, for a conversion
3471 function, we must be careful not to unconditionally look at
3472 DECL_NAME here. */
3476 else
3477 {
3479 complain);
3482 }
3483 }
3485 /* Free all the conversions we allocated. */
3489 }
3491 static void
3494 {
3499 else
3503 {
3508 else
3518 else
3527 else
3537 else
3547 else
3550 else
3554 else
3558 }
3559 }
3561 /* Return the implicit conversion sequence that could be used to
3562 convert E1 to E2 in [expr.cond]. */
3566 {
3572 /* [expr.cond]
3574 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3575 implicitly converted (clause _conv_) to the type "reference to
3576 T2", subject to the constraint that in the conversion the
3577 reference must bind directly (_dcl.init.ref_) to E1. */
3579 {
3581 t1,
3582 e1,
3587 }
3589 /* [expr.cond]
3591 If E1 and E2 have class type, and the underlying class types are
3592 the same or one is a base class of the other: E1 can be converted
3593 to match E2 if the class of T2 is the same type as, or a base
3594 class of, the class of T1, and the cv-qualification of T2 is the
3595 same cv-qualification as, or a greater cv-qualification than, the
3596 cv-qualification of T1. If the conversion is applied, E1 is
3597 changed to an rvalue of type T2 that still refers to the original
3598 source class object (or the appropriate subobject thereof). */
3601 {
3603 {
3608 else
3611 }
3612 else
3614 }
3615 else
3616 /* [expr.cond]
3618 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3619 converted to the type that expression E2 would have if E2 were
3620 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3622 LOOKUP_IMPLICIT);
3623 }
3625 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3626 arguments to the conditional expression. */
3628 tree
3630 tsubst_flags_t complain)
3631 {
3632 tree arg2_type;
3633 tree arg3_type;
3641 /* As a G++ extension, the second argument to the conditional can be
3642 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3643 c'.) If the second operand is omitted, make sure it is
3644 calculated only once. */
3646 {
3651 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3654 else
3656 }
3658 /* [expr.cond]
3660 The first expression is implicitly converted to bool (clause
3661 _conv_). */
3663 LOOKUP_NORMAL);
3665 /* If something has already gone wrong, just pass that fact up the
3666 tree. */
3672 /* [expr.cond]
3674 If either the second or the third operand has type (possibly
3675 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3676 array-to-pointer (_conv.array_), and function-to-pointer
3677 (_conv.func_) standard conversions are performed on the second
3678 and third operands. */
3682 {
3683 /* Do the conversions. We don't these for `void' type arguments
3684 since it can't have any effect and since decay_conversion
3685 does not handle that case gracefully. */
3693 /* [expr.cond]
3695 One of the following shall hold:
3697 --The second or the third operand (but not both) is a
3698 throw-expression (_except.throw_); the result is of the
3699 type of the other and is an rvalue.
3701 --Both the second and the third operands have type void; the
3702 result is of type void and is an rvalue.
3704 We must avoid calling force_rvalue for expressions of type
3705 "void" because it will complain that their value is being
3706 used. */
3709 {
3714 }
3717 {
3722 }
3725 else
3726 {
3728 {
3731 "is of type %<void%>, "
3732 "but the third operand is neither a throw-expression "
3734 else
3736 "is of type %<void%>, "
3737 "but the second operand is neither a throw-expression "
3739 }
3741 }
3745 }
3746 /* [expr.cond]
3748 Otherwise, if the second and third operand have different types,
3749 and either has (possibly cv-qualified) class type, an attempt is
3750 made to convert each of those operands to the type of the other. */
3753 {
3757 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3763 /* [expr.cond]
3765 If both can be converted, or one can be converted but the
3766 conversion is ambiguous, the program is ill-formed. If
3767 neither can be converted, the operands are left unchanged and
3768 further checking is performed as described below. If exactly
3769 one conversion is possible, that conversion is applied to the
3770 chosen operand and the converted operand is used in place of
3771 the original operand for the remainder of this section. */
3776 {
3780 }
3782 {
3786 /* Even if CONV2 is a valid conversion, the result of the
3787 conversion may be invalid. For example, if ARG3 has type
3788 "volatile X", and X does not have a copy constructor
3789 accepting a "volatile X&", then even if ARG2 can be
3790 converted to X, the conversion will fail. */
3793 }
3795 {
3801 }
3803 /* Free all the conversions we allocated. */
3809 /* If, after the conversion, both operands have class type,
3810 treat the cv-qualification of both operands as if it were the
3811 union of the cv-qualification of the operands.
3813 The standard is not clear about what to do in this
3814 circumstance. For example, if the first operand has type
3815 "const X" and the second operand has a user-defined
3816 conversion to "volatile X", what is the type of the second
3817 operand after this step? Making it be "const X" (matching
3818 the first operand) seems wrong, as that discards the
3819 qualification without actually performing a copy. Leaving it
3820 as "volatile X" seems wrong as that will result in the
3821 conditional expression failing altogether, even though,
3822 according to this step, the one operand could be converted to
3823 the type of the other. */
3831 }
3833 /* [expr.cond]
3835 If the second and third operands are lvalues and have the same
3836 type, the result is of that type and is an lvalue. */
3840 {
3845 }
3847 /* [expr.cond]
3849 Otherwise, the result is an rvalue. If the second and third
3850 operand do not have the same type, and either has (possibly
3851 cv-qualified) class type, overload resolution is used to
3852 determine the conversions (if any) to be applied to the operands
3853 (_over.match.oper_, _over.built_). */
3857 {
3862 /* Rearrange the arguments so that add_builtin_candidate only has
3863 to know about two args. In build_builtin_candidate, the
3864 arguments are unscrambled. */
3869 COND_EXPR,
3870 NOP_EXPR,
3872 args,
3873 LOOKUP_NORMAL);
3875 /* [expr.cond]
3877 If the overload resolution fails, the program is
3878 ill-formed. */
3881 {
3883 {
3886 }
3888 }
3891 {
3893 {
3896 }
3898 }
3900 /* [expr.cond]
3902 Otherwise, the conversions thus determined are applied, and
3903 the converted operands are used in place of the original
3904 operands for the remainder of this section. */
3913 }
3915 /* [expr.cond]
3917 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3918 and function-to-pointer (_conv.func_) standard conversions are
3919 performed on the second and third operands.
3921 We need to force the lvalue-to-rvalue conversion here for class types,
3922 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3923 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3924 regions. */
3937 /* [expr.cond]
3939 After those conversions, one of the following shall hold:
3941 --The second and third operands have the same type; the result is of
3942 that type. */
3945 /* [expr.cond]
3947 --The second and third operands have arithmetic or enumeration
3948 type; the usual arithmetic conversions are performed to bring
3949 them to a common type, and the result is of that type. */
3954 {
3955 /* In this case, there is always a common type. */
3957 arg3_type);
3961 {
3966 }
3972 {
3976 }
3980 }
3981 /* [expr.cond]
3983 --The second and third operands have pointer type, or one has
3984 pointer type and the other is a null pointer constant; pointer
3985 conversions (_conv.ptr_) and qualification conversions
3986 (_conv.qual_) are performed to bring them to their composite
3987 pointer type (_expr.rel_). The result is of the composite
3988 pointer type.
3990 --The second and third operands have pointer to member type, or
3991 one has pointer to member type and the other is a null pointer
3992 constant; pointer to member conversions (_conv.mem_) and
3993 qualification conversions (_conv.qual_) are performed to bring
3994 them to a common type, whose cv-qualification shall match the
3995 cv-qualification of either the second or the third operand.
3996 The result is of the common type. */
4004 {
4007 complain);
4012 }
4015 {
4020 }
4022 valid_operands:
4025 /* Avoid folding within decltype (c++/42013) and noexcept. */
4028 /* We can't use result_type below, as fold might have returned a
4029 throw_expr. */
4032 {
4033 /* Expand both sides into the same slot, hopefully the target of
4034 the ?: expression. We used to check for TARGET_EXPRs here,
4035 but now we sometimes wrap them in NOP_EXPRs so the test would
4036 fail. */
4039 /* If this expression is an rvalue, but might be mistaken for an
4040 lvalue, we must add a NON_LVALUE_EXPR. */
4042 }
4045 }
4047 /* OPERAND is an operand to an expression. Perform necessary steps
4048 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
4049 returned. */
4051 static tree
4053 {
4055 {
4058 /* Make sure the template type is instantiated now. */
4060 }
4063 }
4065 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
4066 OVERLOAD) to the CANDIDATES, returning an updated list of
4067 CANDIDATES. The ARGS are the arguments provided to the call;
4068 if FIRST_ARG is non-null it is the implicit object argument,
4069 otherwise the first element of ARGS is used if needed. The
4070 EXPLICIT_TARGS are explicit template arguments provided.
4071 TEMPLATE_ONLY is true if only template functions should be
4072 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
4073 add_function_candidate. */
4075 static void
4077 tree return_type,
4082 {
4083 tree ctype;
4087 unification_kind_t strict;
4088 tree fn;
4093 /* Precalculate special handling of constructors and conversion ops. */
4096 {
4100 /* We're doing return_type(x). */
4102 else
4103 /* We're doing x.operator return_type(). */
4105 /* [over.match.funcs] For conversion functions, the function
4106 is considered to be a member of the class of the implicit
4107 object argument for the purpose of defining the type of
4108 the implicit object parameter. */
4110 }
4111 else
4112 {
4114 {
4117 }
4118 else
4119 {
4122 }
4125 }
4129 else
4130 /* Delay creating the implicit this parameter until it is needed. */
4134 {
4135 tree fn_first_arg;
4145 /* Figure out which set of arguments to use. */
4147 {
4148 /* If this function is a non-static member and we didn't get an
4149 implicit object argument, move it out of args. */
4151 {
4153 tree arg;
4160 }
4164 }
4165 else
4166 {
4167 /* Otherwise, just use the list of arguments provided. */
4170 }
4174 fn,
4175 ctype,
4176 explicit_targs,
4177 fn_first_arg,
4178 fn_args,
4179 return_type,
4180 access_path,
4181 conversion_path,
4182 flags,
4183 strict);
4186 fn,
4187 ctype,
4188 fn_first_arg,
4189 fn_args,
4190 access_path,
4191 conversion_path,
4192 flags);
4193 }
4194 }
4196 /* Even unsigned enum types promote to signed int. We don't want to
4197 issue -Wsign-compare warnings for this case. Here ORIG_ARG is the
4198 original argument and ARG is the argument after any conversions
4199 have been applied. We set TREE_NO_WARNING if we have added a cast
4200 from an unsigned enum type to a signed integer type. */
4202 static void
4204 {
4213 }
4215 tree
4218 {
4224 tree fnname;
4242 {
4246 }
4247 else
4253 {
4258 /* Use build_op_new_call and build_op_delete_call instead. */
4262 /* Use build_op_call instead. */
4269 /* These are saved for the sake of warn_logical_operator. */
4275 }
4281 /* Use build_conditional_expr instead. */
4297 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4300 /* Add namespace-scope operators to the list of functions to
4301 consider. */
4306 /* Add class-member operators to the candidate set. */
4308 {
4309 tree fns;
4313 {
4316 }
4324 }
4333 {
4336 /* For these, the built-in candidates set is empty
4337 [over.match.oper]/3. We don't want non-strict matches
4338 because exact matches are always possible with built-in
4339 operators. The built-in candidate set for COMPONENT_REF
4340 would be empty too, but since there are no such built-in
4341 operators, we accept non-strict matches for them. */
4348 }
4352 {
4354 {
4357 /* Don't try anything fancy if we're not allowed to produce
4358 errors. */
4362 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
4363 distinguish between prefix and postfix ++ and
4364 operator++() was used for both, so we allow this with
4365 -fpermissive. */
4367 {
4374 }
4381 else
4387 /* The caller will deal with these. */
4397 {
4398 /* If one of the arguments of the operator represents
4399 an invalid use of member function pointer, try to report
4400 a meaningful error ... */
4405 else
4406 {
4407 /* ... Otherwise, report the more generic
4408 "no matching operator found" error */
4411 }
4412 }
4415 }
4416 }
4417 else
4418 {
4421 {
4423 {
4426 }
4428 }
4430 {
4436 else
4438 }
4439 else
4440 {
4441 /* Give any warnings we noticed during overload resolution. */
4443 {
4447 }
4449 /* Check for comparison of different enum types. */
4451 {
4463 {
4467 }
4471 }
4473 /* We need to strip any leading REF_BIND so that bitfields
4474 don't cause errors. This should not remove any important
4475 conversions, because builtins don't apply to class
4476 objects directly. */
4483 {
4484 /* We need to call warn_logical_operator before
4485 converting arg2 to a boolean_type. */
4495 }
4497 {
4502 }
4504 }
4505 }
4507 user_defined_result_ready:
4509 /* Free all the conversions we allocated. */
4515 builtin:
4521 {
4534 /* Fall through. */
4572 complain),
4573 arg2);
4575 /* The caller will deal with these. */
4583 }
4585 }
4587 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
4588 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
4590 static bool
4592 {
4593 /* A template instance is never a usual deallocation function,
4594 regardless of its signature. */
4599 /* If a class T has a member deallocation function named operator delete
4600 with exactly one parameter, then that function is a usual
4601 (non-placement) deallocation function. If class T does not declare
4602 such an operator delete but does declare a member deallocation
4603 function named operator delete with exactly two parameters, the second
4604 of which has type std::size_t (18.2), then this function is a usual
4605 deallocation function. */
4612 }
4614 /* Build a call to operator delete. This has to be handled very specially,
4615 because the restrictions on what signatures match are different from all
4616 other call instances. For a normal delete, only a delete taking (void *)
4617 or (void *, size_t) is accepted. For a placement delete, only an exact
4618 match with the placement new is accepted.
4620 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4621 ADDR is the pointer to be deleted.
4622 SIZE is the size of the memory block to be deleted.
4623 GLOBAL_P is true if the delete-expression should not consider
4624 class-specific delete operators.
4625 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4627 If this call to "operator delete" is being generated as part to
4628 deallocate memory allocated via a new-expression (as per [expr.new]
4629 which requires that if the initialization throws an exception then
4630 we call a deallocation function), then ALLOC_FN is the allocation
4631 function. */
4633 tree
4636 tree alloc_fn)
4637 {
4651 /* In [class.free]
4653 If the result of the lookup is ambiguous or inaccessible, or if
4654 the lookup selects a placement deallocation function, the
4655 program is ill-formed.
4657 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4658 {
4662 }
4663 else
4669 /* Strip const and volatile from addr. */
4673 {
4674 /* "A declaration of a placement deallocation function matches the
4675 declaration of a placement allocation function if it has the same
4676 number of parameters and, after parameter transformations (8.3.5),
4677 all parameter types except the first are identical."
4679 So we build up the function type we want and ask instantiate_type
4680 to get it for us. */
4692 /* "If the lookup finds the two-parameter form of a usual deallocation
4693 function (3.7.4.2) and that function, considered as a placement
4694 deallocation function, would have been selected as a match for the
4695 allocation function, the program is ill-formed." */
4697 {
4698 /* But if the class has an operator delete (void *), then that is
4699 the usual deallocation function, so we shouldn't complain
4700 about using the operator delete (void *, size_t). */
4703 {
4708 }
4711 ok:;
4712 }
4713 }
4714 else
4715 /* "Any non-placement deallocation function matches a non-placement
4716 allocation function. If the lookup finds a single matching
4717 deallocation function, that function will be called; otherwise, no
4718 deallocation function will be called." */
4721 {
4724 {
4726 /* "If a class T has a member deallocation function named
4727 operator delete with exactly one parameter, then that
4728 function is a usual (non-placement) deallocation
4729 function. If class T does not declare such an operator
4730 delete but does declare a member deallocation function named
4731 operator delete with exactly two parameters, the second of
4732 which has type std::size_t (18.2), then this function is a
4733 usual deallocation function."
4735 So (void*) beats (void*, size_t). */
4738 }
4739 }
4741 /* If we have a matching function, call it. */
4743 {
4746 /* If the FN is a member function, make sure that it is
4747 accessible. */
4751 /* Core issue 901: It's ok to new a type with deleted delete. */
4756 {
4757 /* The placement args might not be suitable for overload
4758 resolution at this point, so build the call directly. */
4767 }
4768 else
4769 {
4770 tree ret;
4778 }
4779 }
4781 /* [expr.new]
4783 If no unambiguous matching deallocation function can be found,
4784 propagating the exception does not cause the object's memory to
4785 be freed. */
4787 {
4790 alloc_fn);
4792 }
4797 }
4799 /* If the current scope isn't allowed to access DECL along
4800 BASETYPE_PATH, give an error. The most derived class in
4801 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4802 the declaration to use in the error diagnostic. */
4804 bool
4806 {
4810 {
4815 else
4819 }
4822 }
4824 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4825 bitwise or of LOOKUP_* values. If any errors are warnings are
4826 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4827 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4828 to NULL. */
4830 static tree
4833 {
4846 else
4849 }
4851 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
4852 EXPR is implicitly converted to type TOTYPE.
4853 FN and ARGNUM are used for diagnostics. */
4855 static void
4857 {
4860 /* Issue warnings about peculiar, but valid, uses of NULL. */
4862 {
4867 else
4870 }
4872 /* Issue warnings if "false" is converted to a NULL pointer */
4877 }
4879 /* Perform the conversions in CONVS on the expression EXPR. FN and
4880 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4881 indicates the `this' argument of a method. INNER is nonzero when
4882 being called to continue a conversion chain. It is negative when a
4883 reference binding will be applied, positive otherwise. If
4884 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4885 conversions will be emitted if appropriate. If C_CAST_P is true,
4886 this conversion is coming from a C-style cast; in that case,
4887 conversions to inaccessible bases are permitted. */
4889 static tree
4893 {
4895 diagnostic_t diag_kind;
4905 {
4908 /* Give a helpful error if this is bad because of excess braces. */
4916 {
4918 {
4922 complain);
4924 }
4929 complain);
4932 }
4934 {
4939 }
4940 else
4944 }
4950 {
4952 {
4959 /* When converting from an init list we consider explicit
4960 constructors, but actually trying to call one is an error. */
4962 /* Unless we're calling it for value-initialization from an
4963 empty list, since that is handled separately in 8.5.4. */
4965 {
4969 else
4971 }
4973 /* Set user_conv_p on the argument conversions, so rvalue/base
4974 handling knows not to allow any more UDCs. */
4980 /* If this is a constructor or a function returning an aggr type,
4981 we need to build up a TARGET_EXPR. */
4983 {
4986 /* Remember that this was list-initialization. */
4989 }
4992 }
4996 {
5002 else
5004 }
5008 /* Convert a constant to its underlying value, unless we are
5009 about to bind it to a reference, in which case we need to
5010 leave it as an lvalue. */
5012 {
5015 /* If __null has been converted to an integer type, we do not
5016 want to warn about uses of EXPR as an integer, rather than
5017 as a pointer. */
5019 }
5023 {
5024 /* Call build_user_type_conversion again for the error. */
5028 }
5032 {
5033 /* Conversion to std::initializer_list<T>. */
5041 /* Convert all the elements. */
5043 {
5050 }
5051 /* Build up the array. */
5052 elttype = cp_build_qualified_type
5060 /* Call the private constructor. */
5062 new_ctor = build_special_member_call
5067 }
5074 };
5079 c_cast_p,
5080 complain);
5085 {
5090 /* Else fall through. */
5093 {
5094 /* We are going to bind a reference directly to a base-class
5095 subobject of EXPR. */
5096 /* Build an expression for `*((base*) &expr)'. */
5102 }
5104 /* Copy-initialization where the cv-unqualified version of the source
5105 type is the same class as, or a derived class of, the class of the
5106 destination [is treated as direct-initialization]. [dcl.init] */
5109 /* This conversion is being done in the context of a user-defined
5110 conversion (i.e. the second step of copy-initialization), so
5111 don't allow any more. */
5115 {
5121 }
5125 {
5130 {
5132 {
5137 }
5139 }
5141 /* If necessary, create a temporary.
5143 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
5144 that need temporaries, even when their types are reference
5145 compatible with the type of reference being bound, so the
5146 upcoming call to cp_build_unary_op (ADDR_EXPR, expr, ...)
5147 doesn't fail. */
5151 {
5157 {
5159 {
5160 /* If the reference is volatile or non-const, we
5161 cannot create a temporary. */
5168 else
5170 }
5172 }
5173 /* If the source is a packed field, and we must use a copy
5174 constructor, then building the target expr will require
5175 binding the field to the reference parameter to the
5176 copy constructor, and we'll end up with an infinite
5177 loop. If we can use a bitwise copy, then we'll be
5178 OK. */
5182 {
5187 }
5189 {
5192 }
5194 }
5196 /* Take the address of the thing to which we will bind the
5197 reference. */
5202 /* Convert it to a pointer to the type referred to by the
5203 reference. This will adjust the pointer if a derived to
5204 base conversion is being performed. */
5206 expr);
5207 /* Convert the pointer to the desired reference type. */
5209 }
5215 /* Warn about deprecated conversion if appropriate. */
5227 c_cast_p);
5231 }
5238 else
5242 }
5244 /* ARG is being passed to a varargs function. Perform any conversions
5245 required. Return the converted value. */
5247 tree
5249 {
5250 /* [expr.call]
5252 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5253 standard conversions are performed. */
5255 /* [expr.call]
5257 If the argument has integral or enumeration type that is subject
5258 to the integral promotions (_conv.prom_), or a floating point
5259 type that is subject to the floating point promotion
5260 (_conv.fpprom_), the value of the argument is converted to the
5261 promoted type before the call. */
5277 {
5278 /* [expr.call] 5.2.2/7:
5279 Passing a potentially-evaluated argument of class type (Clause 9)
5280 with a non-trivial copy constructor or a non-trivial destructor
5281 with no corresponding parameter is conditionally-supported, with
5282 implementation-defined semantics.
5284 We used to just warn here and do a bitwise copy, but now
5285 cp_expr_size will abort if we try to do that.
5287 If the call appears in the context of a sizeof expression,
5288 it is not potentially-evaluated. */
5292 }
5295 }
5297 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
5299 tree
5301 {
5315 {
5316 /* Remove reference types so we don't ICE later on. */
5318 /* conditionally-supported behavior [expr.call] 5.2.2/7. */
5324 }
5327 }
5329 /* TYPE has been given to va_arg. Apply the default conversions which
5330 would have happened when passed via ellipsis. Return the promoted
5331 type, or the passed type if there is no change. */
5333 tree
5335 {
5336 tree promote;
5338 /* Perform the array-to-pointer and function-to-pointer
5339 conversions. */
5347 }
5349 /* ARG is a default argument expression being passed to a parameter of
5350 the indicated TYPE, which is a parameter to FN. Do any required
5351 conversions. Return the converted value. */
5355 tree
5357 {
5359 tree t;
5361 /* If the ARG is an unparsed default argument expression, the
5362 conversion cannot be performed. */
5364 {
5369 }
5371 /* Detect recursion. */
5374 {
5377 }
5383 /* Due to:
5385 [dcl.fct.default]
5387 The names in the expression are bound, and the semantic
5388 constraints are checked, at the point where the default
5389 expressions appears.
5391 we must not perform access checks here. */
5395 {
5399 tf_warning_or_error);
5400 }
5401 else
5402 {
5403 /* We must make a copy of ARG, in case subsequent processing
5404 alters any part of it. For example, during gimplification a
5405 cast of the form (T) &X::f (where "f" is a member function)
5406 will lead to replacing the PTRMEM_CST for &X::f with a
5407 VAR_DECL. We can avoid the copy for constants, since they
5408 are never modified in place. */
5413 tf_warning_or_error);
5415 }
5421 }
5423 /* Returns the type which will really be used for passing an argument of
5424 type TYPE. */
5426 tree
5428 {
5429 /* Pass classes with copy ctors by invisible reference. */
5431 {
5433 /* There are no other pointers to this temporary. */
5435 }
5444 }
5446 /* Actually perform the appropriate conversion. */
5448 tree
5450 {
5451 tree bitfield_type;
5453 /* If VAL is a bitfield, then -- since it has already been converted
5454 to TYPE -- it cannot have a precision greater than TYPE.
5456 If it has a smaller precision, we must widen it here. For
5457 example, passing "int f:3;" to a function expecting an "int" will
5458 not result in any conversion before this point.
5460 If the precision is the same we must not risk widening. For
5461 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
5462 often have type "int", even though the C++ type for the field is
5463 "long long". If the value is being passed to a function
5464 expecting an "int", then no conversions will be required. But,
5465 if we call convert_bitfield_to_declared_type, the bitfield will
5466 be converted to "long long". */
5473 ;
5474 /* Pass classes with copy ctors by invisible reference. */
5484 {
5493 }
5495 }
5497 /* Returns true iff FN is a function with magic varargs, i.e. ones for
5498 which no conversions at all should be done. This is true for some
5499 builtins which don't act like normal functions. */
5501 static bool
5503 {
5506 {
5516 }
5519 }
5521 /* Subroutine of the various build_*_call functions. Overload resolution
5522 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
5523 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
5524 bitmask of various LOOKUP_* flags which apply to the call itself. */
5526 static tree
5528 {
5536 tree val;
5545 /* In a template, there is no need to perform all of the work that
5546 is normally done. We are only interested in the type of the call
5547 expression, i.e., the return type of the function. Any semantic
5548 errors will be deferred until the template is instantiated. */
5550 {
5551 tree expr;
5552 tree return_type;
5560 else
5561 {
5564 tree arg;
5572 }
5575 argarray);
5581 }
5583 /* Give any warnings we noticed during overload resolution. */
5585 {
5589 }
5591 /* Make =delete work with SFINAE. */
5596 {
5597 /* If FN is a template function, two cases must be considered.
5598 For example:
5600 struct A {
5601 protected:
5602 template <class T> void f();
5603 };
5604 template <class T> struct B {
5605 protected:
5606 void g();
5607 };
5608 struct C : A, B<int> {
5609 using A::f; // #1
5610 using B<int>::g; // #2
5611 };
5613 In case #1 where `A::f' is a member template, DECL_ACCESS is
5614 recorded in the primary template but not in its specialization.
5615 We check access of FN using its primary template.
5617 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
5618 because it is a member of class template B, DECL_ACCESS is
5619 recorded in the specialization `B<int>::g'. We cannot use its
5620 primary template because `B<T>::g' and `B<int>::g' may have
5621 different access. */
5626 else
5628 }
5630 /* Find maximum size of vector to hold converted arguments. */
5637 /* The implicit parameters to a constructor are not considered by overload
5638 resolution, and must be of the proper type. */
5640 {
5642 {
5645 }
5646 else
5647 {
5650 }
5652 /* We should never try to call the abstract constructor. */
5656 {
5660 }
5661 }
5662 /* Bypass access control for 'this' parameter. */
5664 {
5667 ? first_arg
5670 tree converted_arg;
5671 tree base_binfo;
5674 {
5678 else
5680 }
5682 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
5683 X is called for an object that is not of type X, or of a type
5684 derived from X, the behavior is undefined.
5686 So we can assume that anything passed as 'this' is non-null, and
5687 optimize accordingly. */
5689 /* Convert to the base in which the function was declared. */
5692 arg,
5695 /* Check that the base class is accessible. */
5701 /* If fn was found by a using declaration, the conversion path
5702 will be to the derived class, not the base declaring fn. We
5703 must convert from derived to base. */
5713 else
5717 }
5722 {
5728 /* Don't make a copy here if build_call is going to. */
5734 /* Warn about initializer_list deduction that isn't currently in the
5735 working draft. */
5737 && flag_deduce_init_list
5741 {
5754 {
5761 }
5762 }
5769 else
5771 }
5773 /* Default arguments */
5778 /* Ellipsis */
5780 {
5783 /* Do no conversions for magic varargs. */
5785 else
5788 }
5796 /* Avoid actually calling copy constructors and copy assignment operators,
5797 if possible. */
5804 {
5805 tree targ;
5807 tree fa;
5809 /* Pull out the real argument, disregarding const-correctness. */
5815 {
5820 }
5821 else
5826 else
5831 {
5832 /* Copy-list-initialization doesn't require the copy constructor
5833 to be defined. */
5834 }
5835 /* [class.copy]: the copy constructor is implicitly defined even if
5836 the implementation elided its use. */
5839 {
5842 }
5844 /* If we're creating a temp and we already have one, don't create a
5845 new one. If we're not creating a temp but we get one, use
5846 INIT_EXPR to collapse the temp into our target. Otherwise, if the
5847 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
5848 temp or an INIT_EXPR otherwise. */
5853 {
5859 }
5863 {
5865 complain));
5869 }
5870 }
5874 {
5875 tree to = stabilize_reference
5882 {
5883 /* Avoid copying empty classes. */
5888 }
5890 {
5893 }
5894 else
5895 {
5896 /* We must only copy the non-tail padding parts.
5897 Use __builtin_memcpy for the bitwise copy.
5898 FIXME fix 22488 so we can go back to using MODIFY_EXPR
5899 instead of an explicit call to memcpy. */
5909 {
5910 /* If we can't be sure about pointer alignment, a call
5911 to __builtin_memcpy is expanded as a call to memcpy, which
5912 is invalid with identical args. Otherwise it is
5913 expanded as a block move, which should be safe. */
5917 }
5926 }
5929 }
5935 {
5936 tree t;
5942 /* Warn about deprecated virtual functions now, since we're about
5943 to throw away the decl. */
5953 else
5956 }
5957 else
5961 }
5963 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
5964 This function performs no overload resolution, conversion, or other
5965 high-level operations. */
5967 tree
5969 {
5970 tree fndecl;
5974 /* If this call might throw an exception, note that fact. */
5981 /* Check that arguments to builtin functions match the expectations. */
5988 /* Some built-in function calls will be evaluated at compile-time in
5989 fold (). */
6002 }
6006 /* Make an expression which yields the address of the Java interface
6007 method FN. This is achieved by generating a call to libjava's
6008 _Jv_LookupInterfaceMethodIdx(). */
6010 static tree
6012 {
6018 {
6022 java_iface_lookup_fn
6025 }
6027 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
6028 This is the first entry in the vtable. */
6030 tf_warning_or_error),
6031 integer_zero_node);
6033 /* Get the java.lang.Class pointer for the interface being called. */
6038 {
6040 iface);
6042 }
6046 /* Determine the itable index of FN. */
6049 {
6054 i++;
6055 }
6060 java_iface_lookup_fn);
6063 }
6065 /* Returns the value to use for the in-charge parameter when making a
6066 call to a function with the indicated NAME.
6068 FIXME:Can't we find a neater way to do this mapping? */
6070 tree
6072 {
6083 /* This function should only be called with one of the names listed
6084 above. */
6087 }
6089 /* Build a call to a constructor, destructor, or an assignment
6090 operator for INSTANCE, an expression with class type. NAME
6091 indicates the special member function to call; *ARGS are the
6092 arguments. ARGS may be NULL. This may change ARGS. BINFO
6093 indicates the base of INSTANCE that is to be passed as the `this'
6094 parameter to the member function called.
6096 FLAGS are the LOOKUP_* flags to use when processing the call.
6098 If NAME indicates a complete object constructor, INSTANCE may be
6099 NULL_TREE. In this case, the caller will call build_cplus_new to
6100 store the newly constructed object into a VAR_DECL. */
6102 tree
6105 {
6106 tree fns;
6107 /* The type of the subobject to be constructed or destroyed. */
6108 tree class_type;
6110 tree ret;
6119 {
6120 /* Resolve the name. */
6125 }
6131 /* Handle the special case where INSTANCE is NULL_TREE. */
6133 {
6136 }
6137 else
6138 {
6144 /* Convert to the base class, if necessary. */
6147 {
6149 /* For constructors and destructors, either the base is
6150 non-virtual, or it is virtual but we are doing the
6151 conversion from a constructor or destructor for the
6152 complete object. In either case, we can convert
6153 statically. */
6155 else
6156 /* However, for assignment operators, we must convert
6157 dynamically if the base is virtual. */
6160 }
6161 }
6167 /* When making a call to a constructor or destructor for a subobject
6168 that uses virtual base classes, pass down a pointer to a VTT for
6169 the subobject. */
6173 {
6174 tree vtt;
6175 tree sub_vtt;
6177 /* If the current function is a complete object constructor
6178 or destructor, then we fetch the VTT directly.
6179 Otherwise, we look it up using the VTT we were given. */
6185 current_vtt_parm,
6186 vtt);
6192 {
6195 }
6198 }
6203 complain);
6209 }
6211 /* Return the NAME, as a C string. The NAME indicates a function that
6212 is a member of TYPE. *FREE_P is set to true if the caller must
6213 free the memory returned.
6215 Rather than go through all of this, we should simply set the names
6216 of constructors and destructors appropriately, and dispense with
6217 ctor_identifier, dtor_identifier, etc. */
6221 {
6224 /* Assume that we will not allocate memory. */
6226 /* Constructors and destructors are special. */
6228 {
6229 pretty_name
6231 /* For a destructor, add the '~'. */
6235 {
6237 /* Remember that we need to free the memory allocated. */
6239 }
6240 }
6242 {
6245 TFF_PLAIN_IDENTIFIER),
6246 NULL);
6247 /* Remember that we need to free the memory allocated. */
6249 }
6250 else
6254 }
6256 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
6257 be set, upon return, to the function called. ARGS may be NULL.
6258 This may change ARGS. */
6260 tree
6264 {
6268 tree access_binfo;
6269 tree optype;
6271 tree instance_ptr;
6272 tree name;
6275 tree call;
6276 tree fn;
6279 tree orig_instance;
6280 tree orig_fns;
6286 /* We don't know what function we're going to call, yet. */
6295 {
6299 }
6304 /* Dismantle the baselink to collect all the information we need. */
6311 {
6315 }
6326 {
6331 }
6334 /* Under DR 147 A::A() is an invalid constructor call,
6335 not a functional cast. */
6337 {
6347 complain);
6349 }
6351 /* Figure out whether to skip the first argument for the error
6352 message we will display to users if an error occurs. We don't
6353 want to display any compiler-generated arguments. The "this"
6354 pointer hasn't been added yet. However, we must remove the VTT
6355 pointer if this is a call to a base-class constructor or
6356 destructor. */
6359 {
6360 /* Callers should explicitly indicate whether they want to construct
6361 the complete object or just the part without virtual bases. */
6363 /* Similarly for destructors. */
6365 /* Remove the VTT pointer, if present. */
6369 }
6371 /* Process the argument list. */
6373 {
6377 }
6381 /* It's OK to call destructors and constructors on cv-qualified objects.
6382 Therefore, convert the INSTANCE_PTR to the unqualified type, if
6383 necessary. */
6386 {
6390 }
6396 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6399 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
6400 initializer, not T({ }). */
6404 {
6411 }
6412 else
6413 {
6417 }
6422 {
6424 {
6431 else
6432 {
6435 tree arglist;
6446 }
6448 }
6450 }
6451 else
6452 {
6455 {
6458 tree arglist;
6461 {
6467 arglist);
6471 }
6473 }
6474 else
6475 {
6484 /* This is not an error, it is runtime undefined
6485 behavior. */
6487 "pure virtual %q#D called from constructor"
6489 fn);
6493 {
6496 fn);
6498 }
6499 else
6500 {
6504 /* Now we know what function is being called. */
6507 /* Build the actual CALL_EXPR. */
6509 /* In an expression of the form `a->f()' where `f' turns
6510 out to be a static member function, `a' is
6511 none-the-less evaluated. */
6520 /* An explicit call of the form "x->~X()" has type
6521 "void". However, on platforms where destructors
6522 return "this" (i.e., those where
6523 targetm.cxx.cdtor_returns_this is true), such calls
6524 will appear to have a return value of pointer type
6525 to the low-level call machinery. We do not want to
6526 change the low-level machinery, since we want to be
6527 able to optimize "delete f()" on such platforms as
6528 "operator delete(~X(f()))" (rather than generating
6529 "t = f(), ~X(t), operator delete (t)"). */
6531 }
6532 }
6533 }
6536 {
6542 {
6545 }
6548 call = (build_min_non_dep_call_vec
6552 orig_args));
6556 }
6558 /* Free all the conversions we allocated. */
6565 }
6567 /* Returns true iff standard conversion sequence ICS1 is a proper
6568 subsequence of ICS2. */
6570 static bool
6572 {
6573 /* We can assume that a conversion of the same code
6574 between the same types indicates a subsequence since we only get
6575 here if the types we are converting from are the same. */
6582 {
6592 /* At this point, ICS1 cannot be a proper subsequence of
6593 ICS2. We can get a USER_CONV when we are comparing the
6594 second standard conversion sequence of two user conversion
6595 sequences. */
6605 }
6606 }
6608 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
6609 be any _TYPE nodes. */
6611 bool
6613 {
6617 /* We only allow proper derivation here. The DERIVED_FROM_P macro
6618 considers every class derived from itself. */
6621 }
6623 /* We build the ICS for an implicit object parameter as a pointer
6624 conversion sequence. However, such a sequence should be compared
6625 as if it were a reference conversion sequence. If ICS is the
6626 implicit conversion sequence for an implicit object parameter,
6627 modify it accordingly. */
6629 static void
6631 {
6633 {
6634 /* [over.match.funcs]
6636 For non-static member functions, the type of the
6637 implicit object parameter is "reference to cv X"
6638 where X is the class of which the function is a
6639 member and cv is the cv-qualification on the member
6640 function declaration. */
6642 tree reference_type;
6644 /* The `this' parameter is a pointer to a class type. Make the
6645 implicit conversion talk about a reference to that same class
6646 type. */
6659 }
6660 }
6662 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
6663 and return the initial reference binding conversion. Otherwise,
6664 leave *ICS unchanged and return NULL. */
6668 {
6670 {
6675 }
6678 }
6680 /* Compare two implicit conversion sequences according to the rules set out in
6681 [over.ics.rank]. Return values:
6683 1: ics1 is better than ics2
6684 -1: ics2 is better than ics1
6685 0: ics1 and ics2 are indistinguishable */
6687 static int
6689 {
6690 tree from_type1;
6691 tree from_type2;
6692 tree to_type1;
6693 tree to_type2;
6700 /* REF_BINDING is nonzero if the result of the conversion sequence
6701 is a reference type. In that case REF_CONV is the reference
6702 binding conversion. */
6706 /* Handle implicit object parameters. */
6710 /* Handle reference parameters. */
6714 /* List-initialization sequence L1 is a better conversion sequence than
6715 list-initialization sequence L2 if L1 converts to
6716 std::initializer_list<X> for some X and L2 does not. */
6722 /* [over.ics.rank]
6724 When comparing the basic forms of implicit conversion sequences (as
6725 defined in _over.best.ics_)
6727 --a standard conversion sequence (_over.ics.scs_) is a better
6728 conversion sequence than a user-defined conversion sequence
6729 or an ellipsis conversion sequence, and
6731 --a user-defined conversion sequence (_over.ics.user_) is a
6732 better conversion sequence than an ellipsis conversion sequence
6733 (_over.ics.ellipsis_). */
6743 {
6744 /* XXX Isn't this an extension? */
6745 /* Both ICS are bad. We try to make a decision based on what
6746 would have happened if they'd been good. */
6754 /* We couldn't make up our minds; try to figure it out below. */
6755 }
6758 /* Both conversions are ellipsis conversions or both are building a
6759 std::initializer_list. */
6762 /* User-defined conversion sequence U1 is a better conversion sequence
6763 than another user-defined conversion sequence U2 if they contain the
6764 same user-defined conversion operator or constructor and if the sec-
6765 ond standard conversion sequence of U1 is better than the second
6766 standard conversion sequence of U2. */
6769 {
6783 {
6786 }
6787 else
6788 {
6789 /* For ambiguous or aggregate conversions, use the target type as
6790 a proxy for the conversion function. */
6793 }
6795 /* We can just fall through here, after setting up
6796 FROM_TYPE1 and FROM_TYPE2. */
6799 }
6800 else
6801 {
6805 /* We're dealing with two standard conversion sequences.
6807 [over.ics.rank]
6809 Standard conversion sequence S1 is a better conversion
6810 sequence than standard conversion sequence S2 if
6812 --S1 is a proper subsequence of S2 (comparing the conversion
6813 sequences in the canonical form defined by _over.ics.scs_,
6814 excluding any Lvalue Transformation; the identity
6815 conversion sequence is considered to be a subsequence of
6816 any non-identity conversion sequence */
6827 }
6829 /* One sequence can only be a subsequence of the other if they start with
6830 the same type. They can start with different types when comparing the
6831 second standard conversion sequence in two user-defined conversion
6832 sequences. */
6834 {
6839 }
6841 /* [over.ics.rank]
6843 Or, if not that,
6845 --the rank of S1 is better than the rank of S2 (by the rules
6846 defined below):
6848 Standard conversion sequences are ordered by their ranks: an Exact
6849 Match is a better conversion than a Promotion, which is a better
6850 conversion than a Conversion.
6852 Two conversion sequences with the same rank are indistinguishable
6853 unless one of the following rules applies:
6855 --A conversion that does not a convert a pointer, pointer to member,
6856 or std::nullptr_t to bool is better than one that does.
6858 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
6859 so that we do not have to check it explicitly. */
6868 /* A conversion from scalar arithmetic type to complex is worse than a
6869 conversion between scalar arithmetic types. */
6876 {
6879 else
6881 }
6887 {
6892 }
6893 /* The rules for pointers to members A::* are just like the rules
6894 for pointers A*, except opposite: if B is derived from A then
6895 A::* converts to B::*, not vice versa. For that reason, we
6896 switch the from_ and to_ variables here. */
6903 {
6908 }
6913 {
6914 /* This was one of the pointer or pointer-like conversions.
6916 [over.ics.rank]
6918 --If class B is derived directly or indirectly from class A,
6919 conversion of B* to A* is better than conversion of B* to
6920 void*, and conversion of A* to void* is better than
6921 conversion of B* to void*. */
6924 {
6926 deref_from_type2))
6929 deref_from_type1))
6931 }
6934 {
6936 {
6938 {
6940 deref_to_type1))
6942 }
6943 /* We know that DEREF_TO_TYPE1 is `void' here. */
6945 deref_to_type2))
6947 }
6948 }
6951 {
6952 /* [over.ics.rank]
6954 --If class B is derived directly or indirectly from class A
6955 and class C is derived directly or indirectly from B,
6957 --conversion of C* to B* is better than conversion of C* to
6958 A*,
6960 --conversion of B* to A* is better than conversion of C* to
6961 A* */
6963 {
6965 deref_to_type2))
6968 deref_to_type1))
6970 }
6972 {
6974 deref_from_type1))
6977 deref_from_type2))
6979 }
6980 }
6981 }
6984 {
6987 /* [over.ics.rank]
6989 --binding of an expression of type C to a reference of type
6990 B& is better than binding an expression of type C to a
6991 reference of type A&
6993 --conversion of C to B is better than conversion of C to A, */
6996 {
7001 }
7002 }
7005 {
7008 /* [over.ics.rank]
7010 --binding of an expression of type B to a reference of type
7011 A& is better than binding an expression of type C to a
7012 reference of type A&,
7014 --conversion of B to A is better than conversion of C to A */
7017 {
7022 }
7023 }
7025 /* [over.ics.rank]
7027 --S1 and S2 differ only in their qualification conversion and yield
7028 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
7029 qualification signature of type T1 is a proper subset of the cv-
7030 qualification signature of type T2 */
7034 {
7038 }
7040 /* [over.ics.rank]
7042 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
7043 to an implicit object parameter, and either S1 binds an lvalue reference
7044 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
7045 reference to an rvalue and S2 binds an lvalue reference
7046 (C++0x draft standard, 13.3.3.2)
7048 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
7049 types to which the references refer are the same type except for
7050 top-level cv-qualifiers, and the type to which the reference
7051 initialized by S2 refers is more cv-qualified than the type to
7052 which the reference initialized by S1 refers */
7055 {
7059 {
7064 }
7069 }
7071 /* Neither conversion sequence is better than the other. */
7073 }
7075 /* The source type for this standard conversion sequence. */
7077 static tree
7079 {
7081 {
7086 }
7088 }
7090 /* Note a warning about preferring WINNER to LOSER. We do this by storing
7091 a pointer to LOSER and re-running joust to produce the warning if WINNER
7092 is actually used. */
7094 static void
7096 {
7102 }
7104 /* Compare two candidates for overloading as described in
7105 [over.match.best]. Return values:
7107 1: cand1 is better than cand2
7108 -1: cand2 is better than cand1
7109 0: cand1 and cand2 are indistinguishable */
7111 static int
7113 {
7119 /* Candidates that involve bad conversions are always worse than those
7120 that don't. */
7126 /* If we have two pseudo-candidates for conversions to the same type,
7127 or two candidates for the same function, arbitrarily pick one. */
7132 /* a viable function F1
7133 is defined to be a better function than another viable function F2 if
7134 for all arguments i, ICSi(F1) is not a worse conversion sequence than
7135 ICSi(F2), and then */
7137 /* for some argument j, ICSj(F1) is a better conversion sequence than
7138 ICSj(F2) */
7140 /* For comparing static and non-static member functions, we ignore
7141 the implicit object parameter of the non-static function. The
7142 standard says to pretend that the static function has an object
7143 parm, but that won't work with operator overloading. */
7146 {
7154 else
7155 {
7158 }
7159 }
7162 {
7168 {
7181 {
7188 else
7193 {
7197 }
7198 else
7200 }
7203 {
7206 }
7208 }
7209 }
7211 /* warn about confusing overload resolution for user-defined conversions,
7212 either between a constructor and a conversion op, or between two
7213 conversion ops. */
7217 {
7223 else
7226 /* We don't want to complain about `X::operator T1 ()'
7227 beating `X::operator T2 () const', when T2 is a no less
7228 cv-qualified version of T1. */
7231 {
7236 {
7239 }
7242 }
7243 else
7249 {
7256 {
7258 }
7259 }
7260 else
7262 }
7267 /* or, if not that,
7268 F1 is a non-template function and F2 is a template function
7269 specialization. */
7276 /* or, if not that,
7277 F1 and F2 are template functions and the function template for F1 is
7278 more specialized than the template for F2 according to the partial
7279 ordering rules. */
7282 {
7283 winner = more_specialized_fn
7286 /* [temp.func.order]: The presence of unused ellipsis and default
7287 arguments has no effect on the partial ordering of function
7288 templates. add_function_candidate() will not have
7289 counted the "this" argument for constructors. */
7293 }
7295 /* or, if not that,
7296 the context is an initialization by user-defined conversion (see
7297 _dcl.init_ and _over.match.user_) and the standard conversion
7298 sequence from the return type of F1 to the destination type (i.e.,
7299 the type of the entity being initialized) is a better conversion
7300 sequence than the standard conversion sequence from the return type
7301 of F2 to the destination type. */
7304 {
7308 }
7310 /* Check whether we can discard a builtin candidate, either because we
7311 have two identical ones or matching builtin and non-builtin candidates.
7313 (Pedantically in the latter case the builtin which matched the user
7314 function should not be added to the overload set, but we spot it here.
7316 [over.match.oper]
7317 ... the builtin candidates include ...
7318 - do not have the same parameter type list as any non-template
7319 non-member candidate. */
7323 {
7329 {
7331 /* Two built-in candidates; arbitrarily pick one. */
7334 /* cand1 is built-in; prefer cand2. */
7336 else
7337 /* cand2 is built-in; prefer cand1. */
7339 }
7340 }
7342 /* If the two function declarations represent the same function (this can
7343 happen with declarations in multiple scopes and arg-dependent lookup),
7344 arbitrarily choose one. But first make sure the default args we're
7345 using match. */
7348 {
7355 {
7356 /* Don't crash if the fn is variadic. */
7361 }
7369 {
7372 {
7374 {
7381 }
7382 else
7385 }
7388 }
7391 }
7393 tweak:
7395 /* Extension: If the worst conversion for one candidate is worse than the
7396 worst conversion for the other, take the first. */
7398 {
7403 {
7408 }
7414 {
7415 /* Don't choose a deleted function over ambiguity. */
7419 {
7421 "ISO C++ says that these are ambiguous, even "
7422 "though the worst conversion for the first is better than "
7426 }
7427 else
7430 }
7431 }
7435 }
7437 /* Given a list of candidates for overloading, find the best one, if any.
7438 This algorithm has a worst case of O(2n) (winner is last), and a best
7439 case of O(n/2) (totally ambiguous); much better than a sorting
7440 algorithm. */
7444 {
7449 /* Walk through the list once, comparing each current champ to the next
7450 candidate, knocking out a candidate or two with each comparison. */
7453 {
7457 else
7458 {
7460 {
7465 }
7466 else
7467 {
7470 }
7473 }
7474 }
7476 /* Make sure the champ is better than all the candidates it hasn't yet
7477 been compared to. */
7480 challenger != champ
7483 {
7487 }
7490 }
7492 /* Returns nonzero if things of type FROM can be converted to TO. */
7494 bool
7496 {
7498 }
7500 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
7502 bool
7504 {
7509 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7513 flags);
7516 /* Free all the conversions we allocated. */
7520 }
7522 /* Like can_convert_arg, but allows dubious conversions as well. */
7524 bool
7526 {
7530 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7532 /* Try to perform the conversion. */
7534 flags);
7535 /* Free all the conversions we allocated. */
7539 }
7541 /* Convert EXPR to TYPE. Return the converted expression.
7543 Note that we allow bad conversions here because by the time we get to
7544 this point we are committed to doing the conversion. If we end up
7545 doing a bad conversion, convert_like will complain. */
7547 tree
7549 {
7556 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7561 flags);
7564 {
7566 {
7567 /* If expr has unknown type, then it is an overloaded function.
7568 Call instantiate_type to get good error messages. */
7573 else
7575 }
7577 }
7579 {
7580 /* In a template, we are only concerned about determining the
7581 type of non-dependent expressions, so we do not have to
7582 perform the actual conversion. */
7585 }
7586 else
7589 /* Free all the conversions we allocated. */
7593 }
7595 tree
7597 {
7599 }
7601 /* Convert EXPR to TYPE (as a direct-initialization) if that is
7602 permitted. If the conversion is valid, the converted expression is
7603 returned. Otherwise, NULL_TREE is returned, except in the case
7604 that TYPE is a class type; in that case, an error is issued. If
7605 C_CAST_P is true, then this direction initialization is taking
7606 place as part of a static_cast being attempted as part of a C-style
7607 cast. */
7609 tree
7611 tree expr,
7613 tsubst_flags_t complain)
7614 {
7620 /* [dcl.init]
7622 If the destination type is a (possibly cv-qualified) class type:
7624 -- If the initialization is direct-initialization ...,
7625 constructors are considered. ... If no constructor applies, or
7626 the overload resolution is ambiguous, the initialization is
7627 ill-formed. */
7629 {
7635 }
7637 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7641 c_cast_p,
7642 LOOKUP_NORMAL);
7645 else
7648 c_cast_p,
7649 complain);
7651 /* Free all the conversions we allocated. */
7655 }
7657 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
7658 is being bound to a temporary. Create and return a new VAR_DECL
7659 with the indicated TYPE; this variable will store the value to
7660 which the reference is bound. */
7662 tree
7664 {
7665 tree var;
7667 /* Create the variable. */
7670 /* Register the variable. */
7672 {
7673 /* Namespace-scope or local static; give it a mangled name. */
7674 tree name;
7681 }
7682 else
7683 /* Create a new cleanup level if necessary. */
7687 }
7689 /* EXPR is the initializer for a variable DECL of reference or
7690 std::initializer_list type. Create, push and return a new VAR_DECL
7691 for the initializer so that it will live as long as DECL. Any
7692 cleanup for the new variable is returned through CLEANUP, and the
7693 code to initialize the new variable is returned through INITP. */
7695 tree
7697 {
7698 tree init;
7699 tree type;
7700 tree var;
7702 /* Create the temporary variable. */
7706 /* If the rvalue is the result of a function call it will be
7707 a TARGET_EXPR. If it is some other construct (such as a
7708 member access expression where the underlying object is
7709 itself the result of a function call), turn it into a
7710 TARGET_EXPR here. It is important that EXPR be a
7711 TARGET_EXPR below since otherwise the INIT_EXPR will
7712 attempt to make a bitwise copy of EXPR to initialize
7713 VAR. */
7716 /* Create the INIT_EXPR that will initialize the temporary
7717 variable. */
7720 {
7725 else
7728 /* We must be careful to destroy the temporary only
7729 after its initialization has taken place. If the
7730 initialization throws an exception, then the
7731 destructor should not be run. We cannot simply
7732 transform INIT into something like:
7734 (INIT, ({ CLEANUP_STMT; }))
7736 because emit_local_var always treats the
7737 initializer as a full-expression. Thus, the
7738 destructor would run too early; it would run at the
7739 end of initializing the reference variable, rather
7740 than at the end of the block enclosing the
7741 reference variable.
7743 The solution is to pass back a cleanup expression
7744 which the caller is responsible for attaching to
7745 the statement tree. */
7746 }
7747 else
7748 {
7752 static_aggregates);
7753 }
7757 }
7759 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
7760 initializing a variable of that TYPE. If DECL is non-NULL, it is
7761 the VAR_DECL being initialized with the EXPR. (In that case, the
7762 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
7763 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
7764 return, if *CLEANUP is no longer NULL, it will be an expression
7765 that should be pushed as a cleanup after the returned expression
7766 is used to initialize DECL.
7768 Return the converted expression. */
7770 tree
7772 tsubst_flags_t complain)
7773 {
7780 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7784 LOOKUP_NORMAL);
7786 {
7788 {
7795 else
7799 }
7801 }
7803 /* If DECL is non-NULL, then this special rule applies:
7805 [class.temporary]
7807 The temporary to which the reference is bound or the temporary
7808 that is the complete object to which the reference is bound
7809 persists for the lifetime of the reference.
7811 The temporaries created during the evaluation of the expression
7812 initializing the reference, except the temporary to which the
7813 reference is bound, are destroyed at the end of the
7814 full-expression in which they are created.
7816 In that case, we store the converted expression into a new
7817 VAR_DECL in a new scope.
7819 However, we want to be careful not to create temporaries when
7820 they are not required. For example, given:
7822 struct B {};
7823 struct D : public B {};
7824 D f();
7825 const B& b = f();
7827 there is no need to copy the return value from "f"; we can just
7828 extend its lifetime. Similarly, given:
7830 struct S {};
7831 struct T { operator S(); };
7832 T t;
7833 const S& s = t;
7835 we can extend the lifetime of the return value of the conversion
7836 operator. */
7839 {
7840 tree var;
7841 tree base_conv_type;
7843 /* Skip over the REF_BIND. */
7845 /* If the next conversion is a BASE_CONV, skip that too -- but
7846 remember that the conversion was required. */
7848 {
7851 }
7852 else
7854 /* Perform the remainder of the conversion. */
7860 tf_warning_or_error);
7863 else
7864 {
7866 {
7867 tree init;
7869 /* Use its address to initialize the reference variable. */
7877 }
7878 else
7879 /* Take the address of EXPR. */
7881 /* If a BASE_CONV was required, perform it now. */
7883 expr = (perform_implicit_conversion
7885 tf_warning_or_error));
7887 }
7888 }
7889 else
7890 /* Perform the conversion. */
7893 /* Free all the conversions we allocated. */
7897 }
7899 /* Returns true iff TYPE is some variant of std::initializer_list. */
7901 bool
7903 {
7907 }
7909 /* Returns true iff DECL is a list constructor: i.e. a constructor which
7910 will accept an argument list of a single std::initializer_list<T>. */
7912 bool
7914 {
7916 tree arg;
7928 /* There are more non-defaulted parms. */
7932 }