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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. */
43 /* The various kinds of conversion. */
46 ck_identity,
47 ck_lvalue,
48 ck_qual,
49 ck_std,
50 ck_ptr,
51 ck_pmem,
52 ck_base,
53 ck_ref_bind,
54 ck_user,
55 ck_ambig,
56 ck_list,
57 ck_aggr,
58 ck_rvalue
61 /* The rank of the conversion. Order of the enumerals matters; better
62 conversions should come earlier in the list. */
65 cr_identity,
66 cr_exact,
67 cr_promotion,
68 cr_std,
69 cr_pbool,
70 cr_user,
71 cr_ellipsis,
72 cr_bad
75 /* An implicit conversion sequence, in the sense of [over.best.ics].
76 The first conversion to be performed is at the end of the chain.
77 That conversion is always a cr_identity conversion. */
81 /* The kind of conversion represented by this step. */
82 conversion_kind kind;
83 /* The rank of this conversion. */
84 conversion_rank rank;
88 /* True if this conversion would be permitted with a bending of
89 language standards, e.g. disregarding pointer qualifiers or
90 converting integers to pointers. */
92 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
93 temporary should be created to hold the result of the
94 conversion. */
96 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
97 from a pointer-to-derived to pointer-to-base is being performed. */
99 /* If KIND is ck_ref_bind, true when either an lvalue reference is
100 being bound to an lvalue expression or an rvalue reference is
101 being bound to an rvalue expression. */
104 /* The type of the expression resulting from the conversion. */
105 tree type;
107 /* The next conversion in the chain. Since the conversions are
108 arranged from outermost to innermost, the NEXT conversion will
109 actually be performed before this conversion. This variant is
110 used only when KIND is neither ck_identity nor ck_ambig. */
112 /* The expression at the beginning of the conversion chain. This
113 variant is used only if KIND is ck_identity or ck_ambig. */
114 tree expr;
115 /* The array of conversions for an initializer_list. */
118 /* The function candidate corresponding to this conversion
119 sequence. This field is only used if KIND is ck_user. */
121 };
123 #define CONVERSION_RANK(NODE) \
124 ((NODE)->bad_p ? cr_bad \
125 : (NODE)->ellipsis_p ? cr_ellipsis \
126 : (NODE)->user_conv_p ? cr_user \
127 : (NODE)->rank)
129 #define BAD_CONVERSION_RANK(NODE) \
130 ((NODE)->ellipsis_p ? cr_ellipsis \
131 : (NODE)->user_conv_p ? cr_user \
132 : (NODE)->rank)
144 #define convert_like(CONV, EXPR, COMPLAIN) \
145 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
148 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
149 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
172 static void add_builtin_candidates
175 static void add_builtin_candidate
179 static void build_builtin_candidate
184 tree);
214 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
215 NAME can take many forms... */
217 bool
219 {
220 /* Just accept something we've already complained about. */
229 {
235 else
237 }
238 else
239 {
240 /* In the case of:
242 template <class T> struct S { ~S(); };
243 int i;
244 i.~S();
246 NAME will be a class template. */
249 }
254 }
256 /* We want the address of a function or method. We avoid creating a
257 pointer-to-member function. */
259 tree
261 {
264 /* We have to do these by hand to avoid real pointer to member
265 functions. */
267 {
269 {
273 }
275 }
276 else
280 }
282 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
283 POINTER_TYPE to those. Note, pointer to member function types
284 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
285 two variants. build_call_a is the primitive taking an array of
286 arguments, while build_call_n is a wrapper that handles varargs. */
288 tree
290 {
293 else
294 {
304 }
305 }
307 tree
309 {
312 tree decl;
313 tree result_type;
314 tree fntype;
324 /* An rvalue has no cv-qualifiers. */
330 {
333 {
334 /* We invoke build_call directly for several library
335 functions. These may have been declared normally if
336 we're building libgcc, so we can't just check
337 DECL_ARTIFICIAL. */
342 }
343 }
344 else
347 /* We check both the decl and the type; a function may be known not to
348 throw without being declared throw(). */
362 /* Don't pass empty class objects by value. This is useful
363 for tags in STL, which are used to control overload resolution.
364 We don't need to handle other cases of copying empty classes. */
369 {
373 }
381 }
383 /* Build something of the form ptr->method (args)
384 or object.method (args). This can also build
385 calls to constructors, and find friends.
387 Member functions always take their class variable
388 as a pointer.
390 INSTANCE is a class instance.
392 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
394 PARMS help to figure out what that NAME really refers to.
396 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
397 down to the real instance type to use for access checking. We need this
398 information to get protected accesses correct.
400 FLAGS is the logical disjunction of zero or more LOOKUP_
401 flags. See cp-tree.h for more info.
403 If this is all OK, calls build_function_call with the resolved
404 member function.
406 This function must also handle being called to perform
407 initialization, promotion/coercion of arguments, and
408 instantiation of default parameters.
410 Note that NAME may refer to an instance variable name. If
411 `operator()()' is defined for the type of that field, then we return
412 that result. */
414 /* New overloading code. */
422 };
424 /* Information for providing diagnostics about why overloading failed. */
427 rr_none,
428 rr_arity,
429 rr_arg_conversion,
430 rr_bad_arg_conversion
431 };
434 /* The index of the argument, 0-based. */
436 /* The type of the actual argument. */
437 tree from_type;
438 /* The type of the formal argument. */
439 tree to_type;
440 };
445 /* Information about an arity mismatch. */
447 /* The expected number of arguments. */
449 /* The actual number of arguments in the call. */
451 /* Whether the call was a varargs call. */
454 /* Information about an argument conversion mismatch. */
456 /* Same, but for bad argument conversions. */
459 };
462 /* The FUNCTION_DECL that will be called if this candidate is
463 selected by overload resolution. */
464 tree fn;
465 /* If not NULL_TREE, the first argument to use when calling this
466 function. */
467 tree first_arg;
468 /* The rest of the arguments to use when calling this function. If
469 there are no further arguments this may be NULL or it may be an
470 empty vector. */
472 /* The implicit conversion sequences for each of the arguments to
473 FN. */
475 /* The number of implicit conversion sequences. */
477 /* If FN is a user-defined conversion, the standard conversion
478 sequence from the type returned by FN to the desired destination
479 type. */
483 /* If FN is a member function, the binfo indicating the path used to
484 qualify the name of FN at the call site. This path is used to
485 determine whether or not FN is accessible if it is selected by
486 overload resolution. The DECL_CONTEXT of FN will always be a
487 (possibly improper) base of this binfo. */
488 tree access_path;
489 /* If FN is a non-static member function, the binfo indicating the
490 subobject to which the `this' pointer should be converted if FN
491 is selected by overload resolution. The type pointed to the by
492 the `this' pointer must correspond to the most derived class
493 indicated by the CONVERSION_PATH. */
494 tree conversion_path;
495 tree template_decl;
496 tree explicit_targs;
499 };
501 /* Returns true iff T is a null pointer constant in the sense of
502 [conv.ptr]. */
504 bool
506 {
507 /* [conv.ptr]
509 A null pointer constant is an integral constant expression
510 (_expr.const_) rvalue of integer type that evaluates to zero or
511 an rvalue of type std::nullptr_t. */
515 {
517 {
522 }
523 else
524 {
529 }
530 }
532 }
534 /* Returns nonzero if PARMLIST consists of only default parms and/or
535 ellipsis. */
537 bool
539 {
545 }
547 /* Allocate N bytes of memory from the conversion obstack. The memory
548 is zeroed before being returned. */
552 {
555 {
558 }
562 }
564 /* Allocate rejection reasons. */
568 {
573 }
577 {
583 }
587 {
594 }
598 {
605 }
607 /* Dynamically allocate a conversion. */
611 {
616 }
618 #ifdef ENABLE_CHECKING
620 /* Make sure that all memory on the conversion obstack has been
621 freed. */
623 void
625 {
629 }
633 /* Dynamically allocate an array of N conversions. */
637 {
639 }
643 {
647 /* Note that the caller is responsible for filling in t->cand for
648 user-defined conversions. */
654 {
670 }
676 }
678 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, a
679 specialization of std::initializer_list<T>, if such a conversion is
680 possible. */
684 {
690 tree val;
692 /* Within a list-initialization we can have more user-defined
693 conversions. */
695 /* But no narrowing conversions. */
699 {
700 conversion *sub
707 }
715 {
723 }
726 }
728 /* Subroutine of build_aggr_conv: check whether CTOR, a braced-init-list,
729 is a valid aggregate initializer for array type ATYPE. */
731 static bool
733 {
737 {
743 else
747 }
749 }
751 /* Represent a conversion from CTOR, a braced-init-list, to TYPE, an
752 aggregate class, if such a conversion is possible. */
756 {
763 {
765 tree val;
770 else
771 {
775 }
781 else
789 }
800 }
802 /* Build a representation of the identity conversion from EXPR to
803 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
807 {
815 }
817 /* Converting from EXPR to TYPE was ambiguous in the sense that there
818 were multiple user-defined conversions to accomplish the job.
819 Build a conversion that indicates that ambiguity. */
823 {
831 }
833 tree
835 {
839 }
841 /* Returns the standard conversion path (see [conv]) from type FROM to type
842 TO, if any. For proper handling of null pointer constants, you must
843 also pass the expression EXPR to convert from. If C_CAST_P is true,
844 this conversion is coming from a C-style cast. */
849 {
856 {
859 }
865 {
873 }
880 {
884 }
886 {
888 {
889 tree bitfield_type;
892 {
895 }
896 }
898 }
900 /* Allow conversion between `__complex__' data types. */
902 {
903 /* The standard conversion sequence to convert FROM to TO is
904 the standard conversion sequence to perform componentwise
905 conversion. */
910 {
913 }
914 else
918 }
923 /* [conv.ptr]
924 A null pointer constant can be converted to a pointer type; ... A
925 null pointer constant of integral type can be converted to an
926 rvalue of type std::nullptr_t. */
933 {
934 /* For backwards brain damage compatibility, allow interconversion of
935 pointers and integers with a pedwarn. */
938 }
940 {
941 /* For backwards brain damage compatibility, allow interconversion of
942 enums and integers with a pedwarn. */
945 }
948 {
949 tree to_pointee;
950 tree from_pointee;
955 ;
959 {
961 from = build_pointer_type
965 }
967 {
972 && (same_type_ignoring_top_level_qualifiers_p
975 {
979 }
982 }
985 /* [conv.ptr]
987 An rvalue of type "pointer to cv D," where D is a
988 class type, can be converted to an rvalue of type
989 "pointer to cv B," where B is a base class (clause
990 _class.derived_) of D. If B is an inaccessible
991 (clause _class.access_) or ambiguous
992 (_class.member.lookup_) base class of D, a program
993 that necessitates this conversion is ill-formed.
994 Therefore, we use DERIVED_FROM_P, and do not check
995 access or uniqueness. */
997 {
998 from =
1004 }
1007 {
1010 }
1011 else
1012 {
1015 }
1020 /* In a C-style cast, we ignore CV-qualification because we
1021 are allowed to perform a static_cast followed by a
1022 const_cast. */
1027 /* converting from string constant to char *. */
1029 /* Allow conversions among compatible ObjC pointer types (base
1030 conversions have been already handled above). */
1035 {
1038 }
1039 else
1043 }
1045 {
1062 }
1064 {
1065 /* [conv.bool]
1067 An rvalue of arithmetic, unscoped enumeration, pointer, or
1068 pointer to member type can be converted to an rvalue of type
1069 bool. ... An rvalue of type std::nullptr_t can be converted
1070 to an rvalue of type bool; */
1076 {
1085 }
1088 }
1089 /* We don't check for ENUMERAL_TYPE here because there are no standard
1090 conversions to enum type. */
1091 /* As an extension, allow conversion to complex type. */
1093 {
1099 /* Give this a better rank if it's a promotion. */
1103 }
1109 {
1113 /* The derived-to-base conversion indicates the initialization
1114 of a parameter with base type from an object of a derived
1115 type. A temporary object is created to hold the result of
1116 the conversion unless we're binding directly to a reference. */
1118 }
1119 else
1126 }
1128 /* Returns nonzero if T1 is reference-related to T2. */
1130 bool
1132 {
1139 /* [dcl.init.ref]
1141 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
1142 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
1143 of T2. */
1147 }
1149 /* Returns nonzero if T1 is reference-compatible with T2. */
1151 static bool
1153 {
1154 /* [dcl.init.ref]
1156 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
1157 reference-related to T2 and cv1 is the same cv-qualification as,
1158 or greater cv-qualification than, cv2. */
1161 }
1163 /* Determine whether or not the EXPR (of class type S) can be
1164 converted to T as in [over.match.ref]. */
1168 {
1169 tree conversions;
1170 tree first_arg;
1172 tree t;
1184 /* [over.match.ref]
1186 Assuming that "cv1 T" is the underlying type of the reference
1187 being initialized, and "cv S" is the type of the initializer
1188 expression, with S a class type, the candidate functions are
1189 selected as follows:
1191 --The conversion functions of S and its base classes are
1192 considered. Those that are not hidden within S and yield type
1193 "reference to cv2 T2", where "cv1 T" is reference-compatible
1194 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
1196 The argument list has one argument, which is the initializer
1197 expression. */
1201 /* Conceptually, we should take the address of EXPR and put it in
1202 the argument list. Unfortunately, however, that can result in
1203 error messages, which we should not issue now because we are just
1204 trying to find a conversion operator. Therefore, we use NULL,
1205 cast to the appropriate type. */
1210 /* We're performing a user-defined conversion to a desired type, so set
1211 this for the benefit of add_candidates. */
1215 {
1226 {
1227 /* Now, see if the conversion function really returns
1228 an lvalue of the appropriate type. From the
1229 point of view of unification, simply returning an
1230 rvalue of the right type is good enough. */
1235 {
1236 /* No need to set cand->reason here; this is most likely
1237 an ambiguous match. If it's not, either this candidate
1238 will win, or we will have identified a reason for it
1239 losing already. */
1241 }
1242 else
1243 {
1245 /* Build a standard conversion sequence indicating the
1246 binding from the reference type returned by the
1247 function to the desired REFERENCE_TYPE. */
1248 identity_conv
1251 NULL_TREE);
1252 cand->second_conv
1253 = (direct_reference_binding
1260 /* Don't allow binding of lvalues to rvalue references. */
1264 }
1265 }
1266 }
1269 /* If none of the conversion functions worked out, let our caller
1270 know. */
1278 /* Now that we know that this is the function we're going to use fix
1279 the dummy first argument. */
1284 /* Build a user-defined conversion sequence representing the
1285 conversion. */
1294 /* Merge it with the standard conversion sequence from the
1295 conversion function's return type to the desired type. */
1299 }
1301 /* A reference of the indicated TYPE is being bound directly to the
1302 expression represented by the implicit conversion sequence CONV.
1303 Return a conversion sequence for this binding. */
1307 {
1308 tree t;
1315 /* [over.ics.rank]
1317 When a parameter of reference type binds directly
1318 (_dcl.init.ref_) to an argument expression, the implicit
1319 conversion sequence is the identity conversion, unless the
1320 argument expression has a type that is a derived class of the
1321 parameter type, in which case the implicit conversion sequence is
1322 a derived-to-base Conversion.
1324 If the parameter binds directly to the result of applying a
1325 conversion function to the argument expression, the implicit
1326 conversion sequence is a user-defined conversion sequence
1327 (_over.ics.user_), with the second standard conversion sequence
1328 either an identity conversion or, if the conversion function
1329 returns an entity of a type that is a derived class of the
1330 parameter type, a derived-to-base conversion. */
1332 {
1333 /* Represent the derived-to-base conversion. */
1335 /* We will actually be binding to the base-class subobject in
1336 the derived class, so we mark this conversion appropriately.
1337 That way, convert_like knows not to generate a temporary. */
1339 }
1341 }
1343 /* Returns the conversion path from type FROM to reference type TO for
1344 purposes of reference binding. For lvalue binding, either pass a
1345 reference type to FROM or an lvalue expression to EXPR. If the
1346 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1347 the conversion returned. If C_CAST_P is true, this
1348 conversion is coming from a C-style cast. */
1352 {
1356 tree tfrom;
1362 {
1367 }
1370 {
1371 /* Anything with reference type is an lvalue. */
1374 }
1377 {
1380 flags);
1383 {
1388 }
1389 }
1398 /* Figure out whether or not the types are reference-related and
1399 reference compatible. We have do do this after stripping
1400 references from FROM. */
1402 /* If this is a C cast, first convert to an appropriately qualified
1403 type, so that we can later do a const_cast to the desired type. */
1409 /* Directly bind reference when target expression's type is compatible with
1410 the reference and expression is an lvalue. In DR391, the wording in
1411 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1412 const and rvalue references to rvalues of compatible class type.
1413 We should also do direct bindings for non-class "rvalues" derived from
1414 rvalue references. */
1416 && (is_lvalue
1421 {
1422 /* [dcl.init.ref]
1424 If the initializer expression
1426 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1427 is reference-compatible with "cv2 T2,"
1429 the reference is bound directly to the initializer expression
1430 lvalue.
1432 [...]
1433 If the initializer expression is an rvalue, with T2 a class type,
1434 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1435 is bound to the object represented by the rvalue or to a sub-object
1436 within that object. */
1442 /* The top-level caller requested that we pretend that the lvalue
1443 be treated as an rvalue. */
1445 else
1446 conv->rvaluedness_matches_p
1451 /* For the purposes of overload resolution, we ignore the fact
1452 this expression is a bitfield or packed field. (In particular,
1453 [over.ics.ref] says specifically that a function with a
1454 non-const reference parameter is viable even if the
1455 argument is a bitfield.)
1457 However, when we actually call the function we must create
1458 a temporary to which to bind the reference. If the
1459 reference is volatile, or isn't const, then we cannot make
1460 a temporary, so we just issue an error when the conversion
1461 actually occurs. */
1464 /* Don't allow binding of lvalues to rvalue references. */
1470 }
1471 /* [class.conv.fct] A conversion function is never used to convert a
1472 (possibly cv-qualified) object to the (possibly cv-qualified) same
1473 object type (or a reference to it), to a (possibly cv-qualified) base
1474 class of that type (or a reference to it).... */
1477 {
1478 /* [dcl.init.ref]
1480 If the initializer expression
1482 -- has a class type (i.e., T2 is a class type) can be
1483 implicitly converted to an lvalue of type "cv3 T3," where
1484 "cv1 T1" is reference-compatible with "cv3 T3". (this
1485 conversion is selected by enumerating the applicable
1486 conversion functions (_over.match.ref_) and choosing the
1487 best one through overload resolution. (_over.match_).
1489 the reference is bound to the lvalue result of the conversion
1490 in the second case. */
1494 }
1496 /* From this point on, we conceptually need temporaries, even if we
1497 elide them. Only the cases above are "direct bindings". */
1501 /* [over.ics.rank]
1503 When a parameter of reference type is not bound directly to an
1504 argument expression, the conversion sequence is the one required
1505 to convert the argument expression to the underlying type of the
1506 reference according to _over.best.ics_. Conceptually, this
1507 conversion sequence corresponds to copy-initializing a temporary
1508 of the underlying type with the argument expression. Any
1509 difference in top-level cv-qualification is subsumed by the
1510 initialization itself and does not constitute a conversion. */
1512 /* [dcl.init.ref]
1514 Otherwise, the reference shall be to a non-volatile const type.
1516 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1520 /* [dcl.init.ref]
1522 Otherwise, a temporary of type "cv1 T1" is created and
1523 initialized from the initializer expression using the rules for a
1524 non-reference copy initialization. If T1 is reference-related to
1525 T2, cv1 must be the same cv-qualification as, or greater
1526 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1530 /* We're generating a temporary now, but don't bind any more in the
1531 conversion (specifically, don't slice the temporary returned by a
1532 conversion operator). */
1535 /* Core issue 899: When [copy-]initializing a temporary to be bound
1536 to the first parameter of a copy constructor (12.8) called with
1537 a single argument in the context of direct-initialization,
1538 explicit conversion functions are also considered.
1540 So don't set LOOKUP_ONLYCONVERTING in that case. */
1546 flags);
1551 /* This reference binding, unlike those above, requires the
1552 creation of a temporary. */
1557 }
1559 /* Returns the implicit conversion sequence (see [over.ics]) from type
1560 FROM to type TO. The optional expression EXPR may affect the
1561 conversion. FLAGS are the usual overloading flags. If C_CAST_P is
1562 true, this conversion is coming from a C-style cast. */
1567 {
1576 else
1583 {
1587 /* Allow conversion from an initializer-list with one element to a
1588 scalar type. */
1590 {
1592 tree elt;
1598 else
1604 {
1607 /* Too many levels of braces, i.e. '{{1}}'. */
1610 }
1611 }
1612 }
1618 {
1632 /* We used to try to bind a reference to a temporary here, but that
1633 is now handled after the recursive call to this function at the end
1634 of reference_binding. */
1636 }
1639 }
1641 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1642 functions. ARGS will not be changed until a single candidate is
1643 selected. */
1651 {
1668 }
1670 /* Return the number of remaining arguments in the parameter list
1671 beginning with ARG. */
1673 static int
1675 {
1680 n++;
1683 }
1685 /* Create an overload candidate for the function or method FN called
1686 with the argument list FIRST_ARG/ARGS and add it to CANDIDATES.
1687 FLAGS is passed on to implicit_conversion.
1689 This does not change ARGS.
1691 CTYPE, if non-NULL, is the type we want to pretend this function
1692 comes from for purposes of overload resolution. */
1699 {
1703 tree parmnode;
1709 /* At this point we should not see any functions which haven't been
1710 explicitly declared, except for friend functions which will have
1711 been found using argument dependent lookup. */
1714 /* The `this', `in_chrg' and VTT arguments to constructors are not
1715 considered in overload resolution. */
1717 {
1721 {
1724 }
1725 }
1726 else
1732 /* 13.3.2 - Viable functions [over.match.viable]
1733 First, to be a viable function, a candidate function shall have enough
1734 parameters to agree in number with the arguments in the list.
1736 We need to check this first; otherwise, checking the ICSes might cause
1737 us to produce an ill-formed template instantiation. */
1741 {
1745 }
1749 {
1753 }
1754 /* When looking for a function from a subobject from an implicit
1755 copy/move constructor/operator=, don't consider anything that takes (a
1756 reference to) an unrelated type. See c++/44909 and core 1092. */
1758 {
1764 else
1767 {
1770 ctype))
1772 }
1774 /* This only applies at the top level. */
1776 }
1781 /* Second, for F to be a viable function, there shall exist for each
1782 argument an implicit conversion sequence that converts that argument
1783 to the corresponding parameter of F. */
1788 {
1798 else
1807 {
1813 /* The type of the implicit object parameter ('this') for
1814 overload resolution is not always the same as for the
1815 function itself; conversion functions are considered to
1816 be members of the class being converted, and functions
1817 introduced by a using-declaration are considered to be
1818 members of the class that uses them.
1820 Since build_over_call ignores the ICS for the `this'
1821 parameter, we can just change the parm type. */
1823 {
1824 parmtype = cp_build_qualified_type
1827 }
1829 /* Core issue 899: When [copy-]initializing a temporary to be bound
1830 to the first parameter of a copy constructor (12.8) called with
1831 a single argument in the context of direct-initialization,
1832 explicit conversion functions are also considered.
1834 So set LOOKUP_COPY_PARM to let reference_binding know that
1835 it's being called in that context. We generalize the above
1836 to handle move constructors and template constructors as well;
1837 the standardese should soon be updated similarly. */
1842 && (same_type_ignoring_top_level_qualifiers_p
1844 {
1846 /* We allow user-defined conversions within init-lists, but
1847 not for the copy constructor. */
1850 }
1851 else
1857 }
1858 else
1859 {
1863 }
1870 {
1874 }
1877 {
1880 }
1881 }
1883 out:
1886 }
1888 /* Create an overload candidate for the conversion function FN which will
1889 be invoked for expression OBJ, producing a pointer-to-function which
1890 will in turn be called with the argument list FIRST_ARG/ARGLIST,
1891 and add it to CANDIDATES. This does not change ARGLIST. FLAGS is
1892 passed on to implicit_conversion.
1894 Actually, we don't really care about FN; we care about the type it
1895 converts to. There may be multiple conversion functions that will
1896 convert to that type, and we rely on build_user_type_conversion_1 to
1897 choose the best one; so when we create our candidate, we record the type
1898 instead of the function. */
1904 {
1922 /* Don't bother looking up the same type twice. */
1927 {
1935 else
1941 {
1943 flags);
1945 }
1949 {
1953 }
1954 else
1955 {
1959 }
1966 {
1969 }
1976 }
1980 {
1984 }
1988 }
1990 static void
1994 {
2008 /* TRUTH_*_EXPR do "contextual conversion to bool", which means explicit
2009 conversion ops are allowed. We handle that here by just checking for
2010 boolean_type_node because other operators don't ask for it. COND_EXPR
2011 also does contextual conversion to bool for the first operand, but we
2012 handle that in build_conditional_expr, and type1 here is operand 2. */
2017 {
2024 {
2026 /* We need something for printing the candidate. */
2029 }
2031 {
2034 }
2036 }
2038 /* For COND_EXPR we rearranged the arguments; undo that now. */
2040 {
2047 else
2048 {
2051 boolean_type_node);
2052 }
2053 }
2060 }
2062 static bool
2064 {
2066 }
2068 /* Returns nonzero if TYPE is a promoted arithmetic type. */
2070 static bool
2072 {
2073 /* [over.built]
2075 In this section, the term promoted integral type is used to refer
2076 to those integral types which are preserved by integral promotion
2077 (including e.g. int and long but excluding e.g. char).
2078 Similarly, the term promoted arithmetic type refers to promoted
2079 integral types plus floating types. */
2083 }
2085 /* Create any builtin operator overload candidates for the operator in
2086 question given the converted operand types TYPE1 and TYPE2. The other
2087 args are passed through from add_builtin_candidates to
2088 build_builtin_candidate.
2090 TYPE1 and TYPE2 may not be permissible, and we must filter them.
2091 If CODE is requires candidates operands of the same type of the kind
2092 of which TYPE1 and TYPE2 are, we add both candidates
2093 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
2095 static void
2099 {
2101 {
2109 }
2112 {
2114 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2115 and VQ is either volatile or empty, there exist candidate operator
2116 functions of the form
2117 VQ T& operator++(VQ T&);
2118 T operator++(VQ T&, int);
2119 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
2120 type other than bool, and VQ is either volatile or empty, there exist
2121 candidate operator functions of the form
2122 VQ T& operator--(VQ T&);
2123 T operator--(VQ T&, int);
2124 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
2125 complete object type, and VQ is either volatile or empty, there exist
2126 candidate operator functions of the form
2127 T*VQ& operator++(T*VQ&);
2128 T*VQ& operator--(T*VQ&);
2129 T* operator++(T*VQ&, int);
2130 T* operator--(T*VQ&, int); */
2139 {
2142 }
2145 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
2146 exist candidate operator functions of the form
2148 T& operator*(T*);
2150 8 For every function type T, there exist candidate operator functions of
2151 the form
2152 T& operator*(T*); */
2162 /* 9 For every type T, there exist candidate operator functions of the form
2163 T* operator+(T*);
2165 10For every promoted arithmetic type T, there exist candidate operator
2166 functions of the form
2167 T operator+(T);
2168 T operator-(T); */
2178 /* 11For every promoted integral type T, there exist candidate operator
2179 functions of the form
2180 T operator~(T); */
2187 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
2188 is the same type as C2 or is a derived class of C2, T is a complete
2189 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
2190 there exist candidate operator functions of the form
2191 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
2192 where CV12 is the union of CV1 and CV2. */
2197 {
2205 }
2208 /* 13For every pair of promoted arithmetic types L and R, there exist can-
2209 didate operator functions of the form
2210 LR operator*(L, R);
2211 LR operator/(L, R);
2212 LR operator+(L, R);
2213 LR operator-(L, R);
2214 bool operator<(L, R);
2215 bool operator>(L, R);
2216 bool operator<=(L, R);
2217 bool operator>=(L, R);
2218 bool operator==(L, R);
2219 bool operator!=(L, R);
2220 where LR is the result of the usual arithmetic conversions between
2221 types L and R.
2223 14For every pair of types T and I, where T is a cv-qualified or cv-
2224 unqualified complete object type and I is a promoted integral type,
2225 there exist candidate operator functions of the form
2226 T* operator+(T*, I);
2227 T& operator[](T*, I);
2228 T* operator-(T*, I);
2229 T* operator+(I, T*);
2230 T& operator[](I, T*);
2232 15For every T, where T is a pointer to complete object type, there exist
2233 candidate operator functions of the form112)
2234 ptrdiff_t operator-(T, T);
2236 16For every pointer or enumeration type T, there exist candidate operator
2237 functions of the form
2238 bool operator<(T, T);
2239 bool operator>(T, T);
2240 bool operator<=(T, T);
2241 bool operator>=(T, T);
2242 bool operator==(T, T);
2243 bool operator!=(T, T);
2245 17For every pointer to member type T, there exist candidate operator
2246 functions of the form
2247 bool operator==(T, T);
2248 bool operator!=(T, T); */
2255 {
2258 }
2271 {
2274 }
2276 {
2279 }
2280 /* Fall through. */
2297 {
2300 }
2304 {
2307 }
2315 {
2318 }
2320 {
2323 }
2326 /* 18For every pair of promoted integral types L and R, there exist candi-
2327 date operator functions of the form
2328 LR operator%(L, R);
2329 LR operator&(L, R);
2330 LR operator^(L, R);
2331 LR operator|(L, R);
2332 L operator<<(L, R);
2333 L operator>>(L, R);
2334 where LR is the result of the usual arithmetic conversions between
2335 types L and R. */
2343 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2347 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
2348 type, VQ is either volatile or empty, and R is a promoted arithmetic
2349 type, there exist candidate operator functions of the form
2350 VQ L& operator=(VQ L&, R);
2351 VQ L& operator*=(VQ L&, R);
2352 VQ L& operator/=(VQ L&, R);
2353 VQ L& operator+=(VQ L&, R);
2354 VQ L& operator-=(VQ L&, R);
2356 20For every pair T, VQ), where T is any type and VQ is either volatile
2357 or empty, there exist candidate operator functions of the form
2358 T*VQ& operator=(T*VQ&, T*);
2360 21For every pair T, VQ), where T is a pointer to member type and VQ is
2361 either volatile or empty, there exist candidate operator functions of
2362 the form
2363 VQ T& operator=(VQ T&, T);
2365 22For every triple T, VQ, I), where T is a cv-qualified or cv-
2366 unqualified complete object type, VQ is either volatile or empty, and
2367 I is a promoted integral type, there exist candidate operator func-
2368 tions of the form
2369 T*VQ& operator+=(T*VQ&, I);
2370 T*VQ& operator-=(T*VQ&, I);
2372 23For every triple L, VQ, R), where L is an integral or enumeration
2373 type, VQ is either volatile or empty, and R is a promoted integral
2374 type, there exist candidate operator functions of the form
2376 VQ L& operator%=(VQ L&, R);
2377 VQ L& operator<<=(VQ L&, R);
2378 VQ L& operator>>=(VQ L&, R);
2379 VQ L& operator&=(VQ L&, R);
2380 VQ L& operator^=(VQ L&, R);
2381 VQ L& operator|=(VQ L&, R); */
2385 {
2389 {
2392 }
2405 if (INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type1) && INTEGRAL_OR_UNSCOPED_ENUMERATION_TYPE_P (type2))
2418 {
2421 }
2426 }
2431 /* [over.built]
2433 For every pair of promoted arithmetic types L and R, there
2434 exist candidate operator functions of the form
2436 LR operator?(bool, L, R);
2438 where LR is the result of the usual arithmetic conversions
2439 between types L and R.
2441 For every type T, where T is a pointer or pointer-to-member
2442 type, there exist candidate operator functions of the form T
2443 operator?(bool, T, T); */
2447 /* That's OK. */
2450 /* Otherwise, the types should be pointers. */
2455 /* We don't check that the two types are the same; the logic
2456 below will actually create two candidates; one in which both
2457 parameter types are TYPE1, and one in which both parameter
2458 types are TYPE2. */
2463 }
2465 /* If we're dealing with two pointer types or two enumeral types,
2466 we need candidates for both of them. */
2475 {
2476 build_builtin_candidate
2478 build_builtin_candidate
2481 }
2483 build_builtin_candidate
2485 }
2487 tree
2489 {
2497 }
2499 /* There are three conditions of builtin candidates:
2501 1) bool-taking candidates. These are the same regardless of the input.
2502 2) pointer-pair taking candidates. These are generated for each type
2503 one of the input types converts to.
2504 3) arithmetic candidates. According to the standard, we should generate
2505 all of these, but I'm trying not to...
2507 Here we generate a superset of the possible candidates for this particular
2508 case. That is a subset of the full set the standard defines, plus some
2509 other cases which the standard disallows. add_builtin_candidate will
2510 filter out the invalid set. */
2512 static void
2516 {
2520 /* TYPES[i] is the set of possible builtin-operator parameter types
2521 we will consider for the Ith argument. */
2526 {
2529 else
2531 }
2534 {
2535 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2536 and VQ is either volatile or empty, there exist candidate operator
2537 functions of the form
2538 VQ T& operator++(VQ T&); */
2548 /* 24There also exist candidate operator functions of the form
2549 bool operator!(bool);
2550 bool operator&&(bool, bool);
2551 bool operator||(bool, bool); */
2554 build_builtin_candidate
2561 build_builtin_candidate
2579 /* Fall through. */
2583 }
2589 {
2591 ;
2593 {
2594 tree convs;
2602 {
2609 }
2615 {
2628 {
2634 }
2638 }
2639 }
2640 else
2641 {
2647 {
2653 }
2655 }
2656 }
2658 /* Run through the possible parameter types of both arguments,
2659 creating candidates with those parameter types. */
2661 {
2663 tree u;
2667 add_builtin_candidate
2670 else
2671 add_builtin_candidate
2674 }
2678 }
2681 /* If TMPL can be successfully instantiated as indicated by
2682 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2684 TMPL is the template. EXPLICIT_TARGS are any explicit template
2685 arguments. ARGLIST is the arguments provided at the call-site.
2686 This does not change ARGLIST. The RETURN_TYPE is the desired type
2687 for conversion operators. If OBJ is NULL_TREE, FLAGS and CTYPE are
2688 as for add_function_candidate. If an OBJ is supplied, FLAGS and
2689 CTYPE are ignored, and OBJ is as for add_conv_candidate. */
2697 {
2707 tree arg;
2710 tree fn;
2713 /* We don't do deduction on the in-charge parameter, the VTT
2714 parameter or 'this'. */
2716 {
2719 else
2721 }
2726 {
2729 else
2731 }
2741 {
2744 }
2748 {
2751 }
2755 args_without_in_chrg,
2756 nargs_without_in_chrg,
2766 /* In [class.copy]:
2768 A member function template is never instantiated to perform the
2769 copy of a class object to an object of its class type.
2771 It's a little unclear what this means; the standard explicitly
2772 does allow a template to be used to copy a class. For example,
2773 in:
2775 struct A {
2776 A(A&);
2777 template <class T> A(const T&);
2778 };
2779 const A f ();
2780 void g () { A a (f ()); }
2782 the member template will be used to make the copy. The section
2783 quoted above appears in the paragraph that forbids constructors
2784 whose only parameter is (a possibly cv-qualified variant of) the
2785 class type, and a logical interpretation is that the intent was
2786 to forbid the instantiation of member templates which would then
2787 have that form. */
2789 {
2792 ctype))
2794 }
2797 /* Aha, this is a conversion function. */
2800 else
2805 /* This situation can occur if a member template of a template
2806 class is specialized. Then, instantiate_template might return
2807 an instantiation of the specialization, in which case the
2808 DECL_TI_TEMPLATE field will point at the original
2809 specialization. For example:
2811 template <class T> struct S { template <class U> void f(U);
2812 template <> void f(int) {}; };
2813 S<double> sd;
2814 sd.f(3);
2816 Here, TMPL will be template <class U> S<double>::f(U).
2817 And, instantiate template will give us the specialization
2818 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2819 for this will point at template <class T> template <> S<T>::f(int),
2820 so that we can find the definition. For the purposes of
2821 overload resolution, however, we want the original TMPL. */
2823 else
2828 fail:
2831 }
2839 unification_kind_t strict)
2840 {
2841 return
2846 }
2854 tree conversion_path)
2855 {
2856 return
2860 }
2862 /* The CANDS are the set of candidates that were considered for
2863 overload resolution. Return the set of viable candidates, or CANDS
2864 if none are viable. If any of the candidates were viable, set
2865 *ANY_VIABLE_P to true. STRICT_P is true if a candidate should be
2866 considered viable only if it is strictly viable. */
2872 {
2883 {
2886 {
2892 }
2893 else
2895 }
2898 }
2900 static bool
2902 {
2907 }
2909 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2910 words, it is about to become the "this" pointer for a member
2911 function call. Take the address of the object. */
2913 static tree
2915 {
2916 /* In a template, we are only concerned about the type of the
2917 expression, so we can take a shortcut. */
2922 }
2924 /* Returns true iff functions are equivalent. Equivalent functions are
2925 not '==' only if one is a function-local extern function or if
2926 both are extern "C". */
2930 {
2939 }
2941 /* Print information about a candidate being rejected due to INFO. */
2943 static void
2945 {
2947 /* Conversion of implicit `this' argument failed. */
2951 else
2954 }
2956 /* Print information about one overload candidate CANDIDATE. MSGSTR
2957 is the text to print before the candidate itself.
2959 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2960 to have been run through gettext by the caller. This wart makes
2961 life simpler in print_z_candidates and for the translators. */
2963 static void
2965 {
2972 {
2982 else
2985 }
2992 else
2994 /* Give the user some information about why this candidate failed. */
2996 {
3000 {
3015 /* This candidate didn't have any issues or we failed to
3016 handle a particular code. Either way... */
3018 }
3019 }
3020 }
3022 static void
3024 {
3032 /* Remove non-viable deleted candidates. */
3035 {
3040 else
3042 }
3043 /* ...if there are any non-deleted ones. */
3047 /* There may be duplicates in the set of candidates. We put off
3048 checking this condition as long as possible, since we have no way
3049 to eliminate duplicates from a set of functions in less than n^2
3050 time. Now we are about to emit an error message, so it is more
3051 permissible to go slowly. */
3053 {
3055 /* Skip builtin candidates and conversion functions. */
3060 {
3064 else
3066 }
3067 }
3070 n_candidates++;
3075 }
3077 /* USER_SEQ is a user-defined conversion sequence, beginning with a
3078 USER_CONV. STD_SEQ is the standard conversion sequence applied to
3079 the result of the conversion function to convert it to the final
3080 desired type. Merge the two sequences into a single sequence,
3081 and return the merged sequence. */
3085 {
3090 /* Find the end of the second conversion sequence. */
3095 /* Replace the identity conversion with the user conversion
3096 sequence. */
3099 /* The entire sequence is a user-conversion sequence. */
3103 }
3105 /* Handle overload resolution for initializing an object of class type from
3106 an initializer list. First we look for a suitable constructor that
3107 takes a std::initializer_list; if we don't find one, we then look for a
3108 non-list constructor.
3110 Parameters are as for add_candidates, except that the arguments are in
3111 the form of a CONSTRUCTOR (the initializer list) rather than a VEC, and
3112 the RETURN_TYPE parameter is replaced by TOTYPE, the desired type. */
3114 static void
3121 {
3126 /* For list-initialization we consider explicit constructors, but
3127 give an error if one is selected. */
3129 /* And we don't allow narrowing conversions. We also use this flag to
3130 avoid the copy constructor call for copy-list-initialization. */
3133 /* Always use the default constructor if the list is empty (DR 990). */
3136 ;
3137 /* If the class has a list ctor, try passing the list as a single
3138 argument first, but only consider list ctors. */
3140 {
3148 }
3152 /* We aren't looking for list-ctors anymore. */
3154 /* We allow more user-defined conversions within an init-list. */
3156 /* But not for the copy ctor. */
3162 }
3164 /* Returns the best overload candidate to perform the requested
3165 conversion. This function is used for three the overloading situations
3166 described in [over.match.copy], [over.match.conv], and [over.match.ref].
3167 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
3168 per [dcl.init.ref], so we ignore temporary bindings. */
3172 {
3183 /* We represent conversion within a hierarchy using RVALUE_CONV and
3184 BASE_CONV, as specified by [over.best.ics]; these become plain
3185 constructor calls, as specified in [dcl.init]. */
3193 {
3198 {
3199 /* [class.conv.fct] A conversion function is never used to
3200 convert a (possibly cv-qualified) object to the (possibly
3201 cv-qualified) same object type (or a reference to it), to a
3202 (possibly cv-qualified) base class of that type (or a
3203 reference to it)... */
3204 }
3205 else
3207 }
3214 /* It's OK to bind a temporary for converting constructor arguments, but
3215 not in converting the return value of a conversion operator. */
3220 {
3226 /* We should never try to call the abstract or base constructor
3227 from here. */
3232 {
3233 /* List-initialization. */
3237 }
3238 else
3239 {
3244 }
3247 {
3250 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
3251 set, then this is copy-initialization. In that case, "The
3252 result of the call is then used to direct-initialize the
3253 object that is the destination of the copy-initialization."
3254 [dcl.init]
3256 We represent this in the conversion sequence with an
3257 rvalue conversion, which means a constructor call. */
3260 cand->second_conv
3262 }
3263 }
3269 {
3273 /* If we are called to convert to a reference type, we are trying to
3274 find an lvalue binding, so don't even consider temporaries. If
3275 we don't find an lvalue binding, the caller will try again to
3276 look for a temporary binding. */
3287 {
3288 conversion *ics
3294 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
3295 copy-initialization. In that case, "The result of the
3296 call is then used to direct-initialize the object that is
3297 the destination of the copy-initialization." [dcl.init]
3299 We represent this in the conversion sequence with an
3300 rvalue conversion, which means a constructor call. But
3301 don't add a second rvalue conversion if there's already
3302 one there. Which there really shouldn't be, but it's
3303 harmless since we'd add it here anyway. */
3311 {
3316 }
3318 {
3321 cand->reason
3324 }
3325 }
3326 }
3334 {
3336 {
3340 }
3347 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
3348 ambiguous conversion is no worse than another user-defined
3349 conversion. */
3352 }
3354 /* Build the user conversion sequence. */
3355 conv = build_conv
3362 /* Remember that this was a list-initialization. */
3366 /* Combine it with the second conversion sequence. */
3374 }
3376 tree
3378 {
3383 {
3388 }
3390 }
3392 /* Subroutine of convert_nontype_argument.
3394 EXPR is an argument for a template non-type parameter of integral or
3395 enumeration type. Do any necessary conversions (that are permitted for
3396 non-type arguments) to convert it to the parameter type.
3398 If conversion is successful, returns the converted expression;
3399 otherwise, returns error_mark_node. */
3401 tree
3403 {
3406 tree t;
3413 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3418 LOOKUP_IMPLICIT);
3420 /* for a non-type template-parameter of integral or
3421 enumeration type, integral promotions (4.5) and integral
3422 conversions (4.7) are applied. */
3423 /* It should be sufficient to check the outermost conversion step, since
3424 there are no qualification conversions to integer type. */
3427 {
3428 /* A conversion function is OK. If it isn't constexpr, we'll
3429 complain later that the argument isn't constant. */
3431 /* The lvalue-to-rvalue conversion is OK. */
3444 /* and fall through. */
3449 }
3453 else
3456 /* Free all the conversions we allocated. */
3460 }
3462 /* Do any initial processing on the arguments to a function call. */
3466 {
3468 tree arg;
3471 {
3475 {
3478 }
3481 }
3483 }
3485 /* Perform overload resolution on FN, which is called with the ARGS.
3487 Return the candidate function selected by overload resolution, or
3488 NULL if the event that overload resolution failed. In the case
3489 that overload resolution fails, *CANDIDATES will be the set of
3490 candidates considered, and ANY_VIABLE_P will be set to true or
3491 false to indicate whether or not any of the candidates were
3492 viable.
3494 The ARGS should already have gone through RESOLVE_ARGS before this
3495 function is called. */
3502 {
3510 /* Check FN. */
3517 {
3521 }
3523 /* Add the various candidate functions. */
3528 LOOKUP_NORMAL,
3529 candidates);
3537 }
3539 /* Print an error message about being unable to build a call to FN with
3540 ARGS. ANY_VIABLE_P indicates whether any candidate functions could
3541 be located; CANDIDATES is a possibly empty list of such
3542 functions. */
3544 static void
3547 {
3554 else
3559 }
3561 /* Return an expression for a call to FN (a namespace-scope function,
3562 or a static member function) with the ARGS. This may change
3563 ARGS. */
3565 tree
3567 tsubst_flags_t complain)
3568 {
3572 tree result;
3575 {
3579 }
3581 /* If this function was found without using argument dependent
3582 lookup, then we want to ignore any undeclared friend
3583 functions. */
3585 {
3590 {
3594 }
3595 }
3597 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3603 {
3605 {
3612 }
3614 }
3615 else
3618 /* Free all the conversions we allocated. */
3622 }
3624 /* Build a call to a global operator new. FNNAME is the name of the
3625 operator (either "operator new" or "operator new[]") and ARGS are
3626 the arguments provided. This may change ARGS. *SIZE points to the
3627 total number of bytes required by the allocation, and is updated if
3628 that is changed here. *COOKIE_SIZE is non-NULL if a cookie should
3629 be used. If this function determines that no cookie should be
3630 used, after all, *COOKIE_SIZE is set to NULL_TREE. If FN is
3631 non-NULL, it will be set, upon return, to the allocation function
3632 called. */
3634 tree
3638 {
3639 tree fns;
3651 /* Based on:
3653 [expr.new]
3655 If this lookup fails to find the name, or if the allocated type
3656 is not a class type, the allocation function's name is looked
3657 up in the global scope.
3659 we disregard block-scope declarations of "operator new". */
3662 /* Figure out what function is being called. */
3665 /* If no suitable function could be found, issue an error message
3666 and give up. */
3668 {
3671 }
3673 /* If a cookie is required, add some extra space. Whether
3674 or not a cookie is required cannot be determined until
3675 after we know which function was called. */
3677 {
3680 {
3681 /* In G++ 3.2, the check was implemented incorrectly; it
3682 looked at the placement expression, rather than the
3683 type of the function. */
3686 ptr_type_node))
3688 }
3689 else
3690 {
3691 tree arg_types;
3694 /* Skip the size_t parameter. */
3696 /* Check the remaining parameters (if any). */
3700 ptr_type_node))
3702 }
3703 /* If we need a cookie, adjust the number of bytes allocated. */
3705 {
3706 /* Update the total size. */
3708 /* Update the argument list to reflect the adjusted size. */
3710 }
3711 else
3713 }
3715 /* Tell our caller which function we decided to call. */
3719 /* Build the CALL_EXPR. */
3721 }
3723 /* Build a new call to operator(). This may change ARGS. */
3725 tree
3727 {
3741 {
3743 /* It's no good looking for an overloaded operator() on a
3744 pointer-to-member-function. */
3745 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3747 }
3750 {
3754 }
3755 else
3759 {
3763 }
3765 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3769 {
3777 }
3782 {
3794 {
3801 add_template_conv_candidate
3805 else
3809 }
3810 }
3814 {
3816 {
3820 }
3822 }
3823 else
3824 {
3827 {
3829 {
3833 }
3835 }
3836 /* Since cand->fn will be a type, not a function, for a conversion
3837 function, we must be careful not to unconditionally look at
3838 DECL_NAME here. */
3842 else
3843 {
3845 complain);
3848 }
3849 }
3851 /* Free all the conversions we allocated. */
3855 }
3857 static void
3860 {
3865 else
3869 {
3874 else
3884 else
3893 else
3903 else
3913 else
3916 else
3920 else
3924 }
3925 }
3927 /* Return the implicit conversion sequence that could be used to
3928 convert E1 to E2 in [expr.cond]. */
3932 {
3938 /* [expr.cond]
3940 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3941 implicitly converted (clause _conv_) to the type "reference to
3942 T2", subject to the constraint that in the conversion the
3943 reference must bind directly (_dcl.init.ref_) to E1. */
3945 {
3947 t1,
3948 e1,
3953 }
3955 /* [expr.cond]
3957 If E1 and E2 have class type, and the underlying class types are
3958 the same or one is a base class of the other: E1 can be converted
3959 to match E2 if the class of T2 is the same type as, or a base
3960 class of, the class of T1, and the cv-qualification of T2 is the
3961 same cv-qualification as, or a greater cv-qualification than, the
3962 cv-qualification of T1. If the conversion is applied, E1 is
3963 changed to an rvalue of type T2 that still refers to the original
3964 source class object (or the appropriate subobject thereof). */
3967 {
3969 {
3974 else
3977 }
3978 else
3980 }
3981 else
3982 /* [expr.cond]
3984 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3985 converted to the type that expression E2 would have if E2 were
3986 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3988 LOOKUP_IMPLICIT);
3989 }
3991 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3992 arguments to the conditional expression. */
3994 tree
3996 tsubst_flags_t complain)
3997 {
3998 tree arg2_type;
3999 tree arg3_type;
4007 /* As a G++ extension, the second argument to the conditional can be
4008 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
4009 c'.) If the second operand is omitted, make sure it is
4010 calculated only once. */
4012 {
4017 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
4020 else
4022 }
4024 /* [expr.cond]
4026 The first expression is implicitly converted to bool (clause
4027 _conv_). */
4029 LOOKUP_NORMAL);
4031 /* If something has already gone wrong, just pass that fact up the
4032 tree. */
4038 /* [expr.cond]
4040 If either the second or the third operand has type (possibly
4041 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
4042 array-to-pointer (_conv.array_), and function-to-pointer
4043 (_conv.func_) standard conversions are performed on the second
4044 and third operands. */
4048 {
4049 /* Do the conversions. We don't these for `void' type arguments
4050 since it can't have any effect and since decay_conversion
4051 does not handle that case gracefully. */
4059 /* [expr.cond]
4061 One of the following shall hold:
4063 --The second or the third operand (but not both) is a
4064 throw-expression (_except.throw_); the result is of the
4065 type of the other and is an rvalue.
4067 --Both the second and the third operands have type void; the
4068 result is of type void and is an rvalue.
4070 We must avoid calling force_rvalue for expressions of type
4071 "void" because it will complain that their value is being
4072 used. */
4075 {
4080 }
4083 {
4088 }
4091 else
4092 {
4094 {
4097 "is of type %<void%>, "
4098 "but the third operand is neither a throw-expression "
4100 else
4102 "is of type %<void%>, "
4103 "but the second operand is neither a throw-expression "
4105 }
4107 }
4111 }
4112 /* [expr.cond]
4114 Otherwise, if the second and third operand have different types,
4115 and either has (possibly cv-qualified) class type, an attempt is
4116 made to convert each of those operands to the type of the other. */
4119 {
4123 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4129 /* [expr.cond]
4131 If both can be converted, or one can be converted but the
4132 conversion is ambiguous, the program is ill-formed. If
4133 neither can be converted, the operands are left unchanged and
4134 further checking is performed as described below. If exactly
4135 one conversion is possible, that conversion is applied to the
4136 chosen operand and the converted operand is used in place of
4137 the original operand for the remainder of this section. */
4142 {
4146 }
4148 {
4152 /* Even if CONV2 is a valid conversion, the result of the
4153 conversion may be invalid. For example, if ARG3 has type
4154 "volatile X", and X does not have a copy constructor
4155 accepting a "volatile X&", then even if ARG2 can be
4156 converted to X, the conversion will fail. */
4159 }
4161 {
4167 }
4169 /* Free all the conversions we allocated. */
4175 /* If, after the conversion, both operands have class type,
4176 treat the cv-qualification of both operands as if it were the
4177 union of the cv-qualification of the operands.
4179 The standard is not clear about what to do in this
4180 circumstance. For example, if the first operand has type
4181 "const X" and the second operand has a user-defined
4182 conversion to "volatile X", what is the type of the second
4183 operand after this step? Making it be "const X" (matching
4184 the first operand) seems wrong, as that discards the
4185 qualification without actually performing a copy. Leaving it
4186 as "volatile X" seems wrong as that will result in the
4187 conditional expression failing altogether, even though,
4188 according to this step, the one operand could be converted to
4189 the type of the other. */
4197 }
4199 /* [expr.cond]
4201 If the second and third operands are lvalues and have the same
4202 type, the result is of that type and is an lvalue. */
4206 {
4211 }
4213 /* [expr.cond]
4215 Otherwise, the result is an rvalue. If the second and third
4216 operand do not have the same type, and either has (possibly
4217 cv-qualified) class type, overload resolution is used to
4218 determine the conversions (if any) to be applied to the operands
4219 (_over.match.oper_, _over.built_). */
4223 {
4228 /* Rearrange the arguments so that add_builtin_candidate only has
4229 to know about two args. In build_builtin_candidate, the
4230 arguments are unscrambled. */
4235 COND_EXPR,
4236 NOP_EXPR,
4238 args,
4239 LOOKUP_NORMAL);
4241 /* [expr.cond]
4243 If the overload resolution fails, the program is
4244 ill-formed. */
4247 {
4249 {
4252 }
4254 }
4257 {
4259 {
4262 }
4264 }
4266 /* [expr.cond]
4268 Otherwise, the conversions thus determined are applied, and
4269 the converted operands are used in place of the original
4270 operands for the remainder of this section. */
4279 }
4281 /* [expr.cond]
4283 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
4284 and function-to-pointer (_conv.func_) standard conversions are
4285 performed on the second and third operands.
4287 We need to force the lvalue-to-rvalue conversion here for class types,
4288 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
4289 that isn't wrapped with a TARGET_EXPR plays havoc with exception
4290 regions. */
4303 /* [expr.cond]
4305 After those conversions, one of the following shall hold:
4307 --The second and third operands have the same type; the result is of
4308 that type. */
4311 /* [expr.cond]
4313 --The second and third operands have arithmetic or enumeration
4314 type; the usual arithmetic conversions are performed to bring
4315 them to a common type, and the result is of that type. */
4320 {
4321 /* In this case, there is always a common type. */
4323 arg3_type);
4325 "implicit conversion from %qT to %qT to "
4327 input_location);
4331 {
4336 }
4342 {
4346 }
4350 }
4351 /* [expr.cond]
4353 --The second and third operands have pointer type, or one has
4354 pointer type and the other is a null pointer constant; pointer
4355 conversions (_conv.ptr_) and qualification conversions
4356 (_conv.qual_) are performed to bring them to their composite
4357 pointer type (_expr.rel_). The result is of the composite
4358 pointer type.
4360 --The second and third operands have pointer to member type, or
4361 one has pointer to member type and the other is a null pointer
4362 constant; pointer to member conversions (_conv.mem_) and
4363 qualification conversions (_conv.qual_) are performed to bring
4364 them to a common type, whose cv-qualification shall match the
4365 cv-qualification of either the second or the third operand.
4366 The result is of the common type. */
4374 {
4377 complain);
4382 }
4385 {
4390 }
4392 valid_operands:
4395 /* Avoid folding within decltype (c++/42013) and noexcept. */
4398 /* We can't use result_type below, as fold might have returned a
4399 throw_expr. */
4402 {
4403 /* Expand both sides into the same slot, hopefully the target of
4404 the ?: expression. We used to check for TARGET_EXPRs here,
4405 but now we sometimes wrap them in NOP_EXPRs so the test would
4406 fail. */
4409 /* If this expression is an rvalue, but might be mistaken for an
4410 lvalue, we must add a NON_LVALUE_EXPR. */
4412 }
4415 }
4417 /* OPERAND is an operand to an expression. Perform necessary steps
4418 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
4419 returned. */
4421 static tree
4423 {
4425 {
4428 /* Make sure the template type is instantiated now. */
4430 }
4433 }
4435 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
4436 OVERLOAD) to the CANDIDATES, returning an updated list of
4437 CANDIDATES. The ARGS are the arguments provided to the call;
4438 if FIRST_ARG is non-null it is the implicit object argument,
4439 otherwise the first element of ARGS is used if needed. The
4440 EXPLICIT_TARGS are explicit template arguments provided.
4441 TEMPLATE_ONLY is true if only template functions should be
4442 considered. CONVERSION_PATH, ACCESS_PATH, and FLAGS are as for
4443 add_function_candidate. */
4445 static void
4447 tree return_type,
4452 {
4453 tree ctype;
4457 unification_kind_t strict;
4458 tree fn;
4463 /* Precalculate special handling of constructors and conversion ops. */
4466 {
4470 /* We're doing return_type(x). */
4472 else
4473 /* We're doing x.operator return_type(). */
4475 /* [over.match.funcs] For conversion functions, the function
4476 is considered to be a member of the class of the implicit
4477 object argument for the purpose of defining the type of
4478 the implicit object parameter. */
4480 }
4481 else
4482 {
4484 {
4487 }
4488 else
4489 {
4492 }
4495 }
4499 else
4500 /* Delay creating the implicit this parameter until it is needed. */
4504 {
4505 tree fn_first_arg;
4515 /* Figure out which set of arguments to use. */
4517 {
4518 /* If this function is a non-static member and we didn't get an
4519 implicit object argument, move it out of args. */
4521 {
4523 tree arg;
4530 }
4534 }
4535 else
4536 {
4537 /* Otherwise, just use the list of arguments provided. */
4540 }
4544 fn,
4545 ctype,
4546 explicit_targs,
4547 fn_first_arg,
4548 fn_args,
4549 return_type,
4550 access_path,
4551 conversion_path,
4552 flags,
4553 strict);
4556 fn,
4557 ctype,
4558 fn_first_arg,
4559 fn_args,
4560 access_path,
4561 conversion_path,
4562 flags);
4563 }
4564 }
4566 /* Even unsigned enum types promote to signed int. We don't want to
4567 issue -Wsign-compare warnings for this case. Here ORIG_ARG is the
4568 original argument and ARG is the argument after any conversions
4569 have been applied. We set TREE_NO_WARNING if we have added a cast
4570 from an unsigned enum type to a signed integer type. */
4572 static void
4574 {
4583 }
4585 tree
4588 {
4594 tree fnname;
4612 {
4616 }
4617 else
4623 {
4628 /* Use build_op_new_call and build_op_delete_call instead. */
4632 /* Use build_op_call instead. */
4639 /* These are saved for the sake of warn_logical_operator. */
4645 }
4651 /* Use build_conditional_expr instead. */
4667 /* Get the high-water mark for the CONVERSION_OBSTACK. */
4670 /* Add namespace-scope operators to the list of functions to
4671 consider. */
4676 /* Add class-member operators to the candidate set. */
4678 {
4679 tree fns;
4683 {
4686 }
4694 }
4703 {
4706 /* For these, the built-in candidates set is empty
4707 [over.match.oper]/3. We don't want non-strict matches
4708 because exact matches are always possible with built-in
4709 operators. The built-in candidate set for COMPONENT_REF
4710 would be empty too, but since there are no such built-in
4711 operators, we accept non-strict matches for them. */
4718 }
4722 {
4724 {
4727 /* Don't try anything fancy if we're not allowed to produce
4728 errors. */
4732 /* Look for an `operator++ (int)'. Pre-1985 C++ didn't
4733 distinguish between prefix and postfix ++ and
4734 operator++() was used for both, so we allow this with
4735 -fpermissive. */
4737 {
4744 }
4751 else
4757 /* The caller will deal with these. */
4767 {
4768 /* If one of the arguments of the operator represents
4769 an invalid use of member function pointer, try to report
4770 a meaningful error ... */
4775 else
4776 {
4777 /* ... Otherwise, report the more generic
4778 "no matching operator found" error */
4781 }
4782 }
4785 }
4786 }
4787 else
4788 {
4791 {
4793 {
4796 }
4798 }
4800 {
4806 else
4808 }
4809 else
4810 {
4811 /* Give any warnings we noticed during overload resolution. */
4813 {
4817 }
4819 /* Check for comparison of different enum types. */
4821 {
4833 {
4837 }
4841 }
4843 /* We need to strip any leading REF_BIND so that bitfields
4844 don't cause errors. This should not remove any important
4845 conversions, because builtins don't apply to class
4846 objects directly. */
4853 {
4854 /* We need to call warn_logical_operator before
4855 converting arg2 to a boolean_type. */
4865 }
4867 {
4872 }
4874 }
4875 }
4877 user_defined_result_ready:
4879 /* Free all the conversions we allocated. */
4885 builtin:
4891 {
4904 /* Fall through. */
4942 complain),
4943 arg2);
4945 /* The caller will deal with these. */
4953 }
4955 }
4957 /* Returns true iff T, an element of an OVERLOAD chain, is a usual
4958 deallocation function (3.7.4.2 [basic.stc.dynamic.deallocation]). */
4960 static bool
4962 {
4963 /* A template instance is never a usual deallocation function,
4964 regardless of its signature. */
4969 /* If a class T has a member deallocation function named operator delete
4970 with exactly one parameter, then that function is a usual
4971 (non-placement) deallocation function. If class T does not declare
4972 such an operator delete but does declare a member deallocation
4973 function named operator delete with exactly two parameters, the second
4974 of which has type std::size_t (18.2), then this function is a usual
4975 deallocation function. */
4982 }
4984 /* Build a call to operator delete. This has to be handled very specially,
4985 because the restrictions on what signatures match are different from all
4986 other call instances. For a normal delete, only a delete taking (void *)
4987 or (void *, size_t) is accepted. For a placement delete, only an exact
4988 match with the placement new is accepted.
4990 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4991 ADDR is the pointer to be deleted.
4992 SIZE is the size of the memory block to be deleted.
4993 GLOBAL_P is true if the delete-expression should not consider
4994 class-specific delete operators.
4995 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4997 If this call to "operator delete" is being generated as part to
4998 deallocate memory allocated via a new-expression (as per [expr.new]
4999 which requires that if the initialization throws an exception then
5000 we call a deallocation function), then ALLOC_FN is the allocation
5001 function. */
5003 tree
5006 tree alloc_fn)
5007 {
5021 /* In [class.free]
5023 If the result of the lookup is ambiguous or inaccessible, or if
5024 the lookup selects a placement deallocation function, the
5025 program is ill-formed.
5027 Therefore, we ask lookup_fnfields to complain about ambiguity. */
5028 {
5032 }
5033 else
5039 /* Strip const and volatile from addr. */
5043 {
5044 /* "A declaration of a placement deallocation function matches the
5045 declaration of a placement allocation function if it has the same
5046 number of parameters and, after parameter transformations (8.3.5),
5047 all parameter types except the first are identical."
5049 So we build up the function type we want and ask instantiate_type
5050 to get it for us. */
5062 /* "If the lookup finds the two-parameter form of a usual deallocation
5063 function (3.7.4.2) and that function, considered as a placement
5064 deallocation function, would have been selected as a match for the
5065 allocation function, the program is ill-formed." */
5067 {
5068 /* But if the class has an operator delete (void *), then that is
5069 the usual deallocation function, so we shouldn't complain
5070 about using the operator delete (void *, size_t). */
5073 {
5078 }
5081 ok:;
5082 }
5083 }
5084 else
5085 /* "Any non-placement deallocation function matches a non-placement
5086 allocation function. If the lookup finds a single matching
5087 deallocation function, that function will be called; otherwise, no
5088 deallocation function will be called." */
5091 {
5094 {
5096 /* "If a class T has a member deallocation function named
5097 operator delete with exactly one parameter, then that
5098 function is a usual (non-placement) deallocation
5099 function. If class T does not declare such an operator
5100 delete but does declare a member deallocation function named
5101 operator delete with exactly two parameters, the second of
5102 which has type std::size_t (18.2), then this function is a
5103 usual deallocation function."
5105 So (void*) beats (void*, size_t). */
5108 }
5109 }
5111 /* If we have a matching function, call it. */
5113 {
5116 /* If the FN is a member function, make sure that it is
5117 accessible. */
5121 /* Core issue 901: It's ok to new a type with deleted delete. */
5126 {
5127 /* The placement args might not be suitable for overload
5128 resolution at this point, so build the call directly. */
5137 }
5138 else
5139 {
5140 tree ret;
5148 }
5149 }
5151 /* [expr.new]
5153 If no unambiguous matching deallocation function can be found,
5154 propagating the exception does not cause the object's memory to
5155 be freed. */
5157 {
5160 alloc_fn);
5162 }
5167 }
5169 /* If the current scope isn't allowed to access DECL along
5170 BASETYPE_PATH, give an error. The most derived class in
5171 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
5172 the declaration to use in the error diagnostic. */
5174 bool
5176 {
5180 {
5185 else
5189 }
5192 }
5194 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
5195 bitwise or of LOOKUP_* values. If any errors are warnings are
5196 generated, set *DIAGNOSTIC_FN to "error" or "warning",
5197 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
5198 to NULL. */
5200 static tree
5203 {
5216 else
5219 }
5221 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
5222 EXPR is implicitly converted to type TOTYPE.
5223 FN and ARGNUM are used for diagnostics. */
5225 static void
5227 {
5230 /* Issue warnings about peculiar, but valid, uses of NULL. */
5232 {
5237 else
5240 }
5242 /* Issue warnings if "false" is converted to a NULL pointer */
5247 }
5249 /* Perform the conversions in CONVS on the expression EXPR. FN and
5250 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
5251 indicates the `this' argument of a method. INNER is nonzero when
5252 being called to continue a conversion chain. It is negative when a
5253 reference binding will be applied, positive otherwise. If
5254 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
5255 conversions will be emitted if appropriate. If C_CAST_P is true,
5256 this conversion is coming from a C-style cast; in that case,
5257 conversions to inaccessible bases are permitted. */
5259 static tree
5263 {
5265 diagnostic_t diag_kind;
5275 {
5278 /* Give a helpful error if this is bad because of excess braces. */
5286 {
5288 {
5292 complain);
5294 }
5299 complain);
5302 }
5304 {
5309 }
5310 else
5314 }
5320 {
5322 {
5329 /* When converting from an init list we consider explicit
5330 constructors, but actually trying to call one is an error. */
5332 /* Unless we're calling it for value-initialization from an
5333 empty list, since that is handled separately in 8.5.4. */
5335 {
5339 else
5341 }
5343 /* Set user_conv_p on the argument conversions, so rvalue/base
5344 handling knows not to allow any more UDCs. */
5350 /* If this is a constructor or a function returning an aggr type,
5351 we need to build up a TARGET_EXPR. */
5353 {
5356 /* Remember that this was list-initialization. */
5359 }
5362 }
5366 {
5372 else
5374 }
5378 /* Convert a constant to its underlying value, unless we are
5379 about to bind it to a reference, in which case we need to
5380 leave it as an lvalue. */
5382 {
5385 /* If __null has been converted to an integer type, we do not
5386 want to warn about uses of EXPR as an integer, rather than
5387 as a pointer. */
5389 }
5393 {
5394 /* Call build_user_type_conversion again for the error. */
5398 }
5402 {
5403 /* Conversion to std::initializer_list<T>. */
5411 /* Convert all the elements. */
5413 {
5421 }
5422 /* Build up the array. */
5423 elttype = cp_build_qualified_type
5431 /* Call the private constructor. */
5433 new_ctor = build_special_member_call
5438 }
5445 };
5450 c_cast_p,
5451 complain);
5456 {
5461 /* Else fall through. */
5464 {
5465 /* We are going to bind a reference directly to a base-class
5466 subobject of EXPR. */
5467 /* Build an expression for `*((base*) &expr)'. */
5473 }
5475 /* Copy-initialization where the cv-unqualified version of the source
5476 type is the same class as, or a derived class of, the class of the
5477 destination [is treated as direct-initialization]. [dcl.init] */
5480 /* This conversion is being done in the context of a user-defined
5481 conversion (i.e. the second step of copy-initialization), so
5482 don't allow any more. */
5486 /* Copy-list-initialization doesn't actually involve a copy. */
5490 {
5496 }
5500 {
5505 {
5507 {
5512 }
5514 }
5516 /* If necessary, create a temporary.
5518 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
5519 that need temporaries, even when their types are reference
5520 compatible with the type of reference being bound, so the
5521 upcoming call to cp_build_addr_expr doesn't fail. */
5525 {
5526 /* Otherwise, a temporary of type "cv1 T1" is created and
5527 initialized from the initializer expression using the rules
5528 for a non-reference copy-initialization (8.5). */
5537 {
5539 {
5540 /* If the reference is volatile or non-const, we
5541 cannot create a temporary. */
5548 else
5550 }
5552 }
5553 /* If the source is a packed field, and we must use a copy
5554 constructor, then building the target expr will require
5555 binding the field to the reference parameter to the
5556 copy constructor, and we'll end up with an infinite
5557 loop. If we can use a bitwise copy, then we'll be
5558 OK. */
5562 {
5567 }
5569 {
5572 }
5574 }
5576 /* Take the address of the thing to which we will bind the
5577 reference. */
5582 /* Convert it to a pointer to the type referred to by the
5583 reference. This will adjust the pointer if a derived to
5584 base conversion is being performed. */
5586 expr);
5587 /* Convert the pointer to the desired reference type. */
5589 }
5595 /* Warn about deprecated conversion if appropriate. */
5611 }
5618 else
5622 }
5624 /* ARG is being passed to a varargs function. Perform any conversions
5625 required. Return the converted value. */
5627 tree
5629 {
5630 tree arg_type;
5632 /* [expr.call]
5634 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
5635 standard conversions are performed. */
5638 /* [expr.call]
5640 If the argument has integral or enumeration type that is subject
5641 to the integral promotions (_conv.prom_), or a floating point
5642 type that is subject to the floating point promotion
5643 (_conv.fpprom_), the value of the argument is converted to the
5644 promoted type before the call. */
5649 {
5652 "implicit conversion from %qT to %qT when passing "
5656 }
5668 {
5669 /* [expr.call] 5.2.2/7:
5670 Passing a potentially-evaluated argument of class type (Clause 9)
5671 with a non-trivial copy constructor or a non-trivial destructor
5672 with no corresponding parameter is conditionally-supported, with
5673 implementation-defined semantics.
5675 We used to just warn here and do a bitwise copy, but now
5676 cp_expr_size will abort if we try to do that.
5678 If the call appears in the context of a sizeof expression,
5679 it is not potentially-evaluated. */
5683 }
5686 }
5688 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
5690 tree
5692 {
5706 {
5707 /* Remove reference types so we don't ICE later on. */
5709 /* conditionally-supported behavior [expr.call] 5.2.2/7. */
5715 }
5718 }
5720 /* TYPE has been given to va_arg. Apply the default conversions which
5721 would have happened when passed via ellipsis. Return the promoted
5722 type, or the passed type if there is no change. */
5724 tree
5726 {
5727 tree promote;
5729 /* Perform the array-to-pointer and function-to-pointer
5730 conversions. */
5738 }
5740 /* ARG is a default argument expression being passed to a parameter of
5741 the indicated TYPE, which is a parameter to FN. Do any required
5742 conversions. Return the converted value. */
5746 tree
5748 {
5750 tree t;
5752 /* If the ARG is an unparsed default argument expression, the
5753 conversion cannot be performed. */
5755 {
5760 }
5762 /* Detect recursion. */
5765 {
5768 }
5774 /* Due to:
5776 [dcl.fct.default]
5778 The names in the expression are bound, and the semantic
5779 constraints are checked, at the point where the default
5780 expressions appears.
5782 we must not perform access checks here. */
5786 {
5790 tf_warning_or_error);
5791 }
5792 else
5793 {
5794 /* We must make a copy of ARG, in case subsequent processing
5795 alters any part of it. For example, during gimplification a
5796 cast of the form (T) &X::f (where "f" is a member function)
5797 will lead to replacing the PTRMEM_CST for &X::f with a
5798 VAR_DECL. We can avoid the copy for constants, since they
5799 are never modified in place. */
5804 tf_warning_or_error);
5806 }
5812 }
5814 /* Returns the type which will really be used for passing an argument of
5815 type TYPE. */
5817 tree
5819 {
5820 /* Pass classes with copy ctors by invisible reference. */
5822 {
5824 /* There are no other pointers to this temporary. */
5826 }
5835 }
5837 /* Actually perform the appropriate conversion. */
5839 tree
5841 {
5842 tree bitfield_type;
5844 /* If VAL is a bitfield, then -- since it has already been converted
5845 to TYPE -- it cannot have a precision greater than TYPE.
5847 If it has a smaller precision, we must widen it here. For
5848 example, passing "int f:3;" to a function expecting an "int" will
5849 not result in any conversion before this point.
5851 If the precision is the same we must not risk widening. For
5852 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
5853 often have type "int", even though the C++ type for the field is
5854 "long long". If the value is being passed to a function
5855 expecting an "int", then no conversions will be required. But,
5856 if we call convert_bitfield_to_declared_type, the bitfield will
5857 be converted to "long long". */
5864 ;
5865 /* Pass classes with copy ctors by invisible reference. */
5875 {
5884 }
5886 }
5888 /* Returns true iff FN is a function with magic varargs, i.e. ones for
5889 which no conversions at all should be done. This is true for some
5890 builtins which don't act like normal functions. */
5892 static bool
5894 {
5897 {
5907 }
5910 }
5912 /* Subroutine of the various build_*_call functions. Overload resolution
5913 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
5914 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
5915 bitmask of various LOOKUP_* flags which apply to the call itself. */
5917 static tree
5919 {
5927 tree val;
5936 /* In a template, there is no need to perform all of the work that
5937 is normally done. We are only interested in the type of the call
5938 expression, i.e., the return type of the function. Any semantic
5939 errors will be deferred until the template is instantiated. */
5941 {
5942 tree expr;
5943 tree return_type;
5951 else
5952 {
5955 tree arg;
5963 }
5966 argarray);
5972 }
5974 /* Give any warnings we noticed during overload resolution. */
5976 {
5980 }
5982 /* Make =delete work with SFINAE. */
5987 {
5988 tree access_fn;
5989 /* If FN is a template function, two cases must be considered.
5990 For example:
5992 struct A {
5993 protected:
5994 template <class T> void f();
5995 };
5996 template <class T> struct B {
5997 protected:
5998 void g();
5999 };
6000 struct C : A, B<int> {
6001 using A::f; // #1
6002 using B<int>::g; // #2
6003 };
6005 In case #1 where `A::f' is a member template, DECL_ACCESS is
6006 recorded in the primary template but not in its specialization.
6007 We check access of FN using its primary template.
6009 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
6010 because it is a member of class template B, DECL_ACCESS is
6011 recorded in the specialization `B<int>::g'. We cannot use its
6012 primary template because `B<T>::g' and `B<int>::g' may have
6013 different access. */
6017 else
6020 {
6024 }
6025 else
6027 }
6029 /* If we're checking for implicit delete, don't bother with argument
6030 conversions. */
6032 {
6034 {
6038 }
6042 /* Reject bad conversions now. */
6044 /* else continue to get conversion error. */
6045 }
6047 /* Find maximum size of vector to hold converted arguments. */
6054 /* The implicit parameters to a constructor are not considered by overload
6055 resolution, and must be of the proper type. */
6057 {
6059 {
6062 }
6063 else
6064 {
6067 }
6069 /* We should never try to call the abstract constructor. */
6073 {
6077 }
6078 }
6079 /* Bypass access control for 'this' parameter. */
6081 {
6084 ? first_arg
6087 tree converted_arg;
6088 tree base_binfo;
6091 {
6095 else
6097 }
6099 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
6100 X is called for an object that is not of type X, or of a type
6101 derived from X, the behavior is undefined.
6103 So we can assume that anything passed as 'this' is non-null, and
6104 optimize accordingly. */
6106 /* Convert to the base in which the function was declared. */
6109 arg,
6112 /* Check that the base class is accessible. */
6118 /* If fn was found by a using declaration, the conversion path
6119 will be to the derived class, not the base declaring fn. We
6120 must convert from derived to base. */
6130 else
6134 }
6139 {
6145 /* Don't make a copy here if build_call is going to. */
6151 /* Warn about initializer_list deduction that isn't currently in the
6152 working draft. */
6154 && flag_deduce_init_list
6158 {
6171 {
6178 }
6179 }
6186 else
6188 }
6190 /* Default arguments */
6195 /* Ellipsis */
6197 {
6200 /* Do no conversions for magic varargs. */
6202 else
6205 }
6213 /* Avoid actually calling copy constructors and copy assignment operators,
6214 if possible. */
6221 {
6222 tree targ;
6224 tree fa;
6227 /* Pull out the real argument, disregarding const-correctness. */
6233 {
6238 }
6239 else
6244 else
6247 /* [class.copy]: the copy constructor is implicitly defined even if
6248 the implementation elided its use. */
6250 {
6253 }
6255 /* If we're creating a temp and we already have one, don't create a
6256 new one. If we're not creating a temp but we get one, use
6257 INIT_EXPR to collapse the temp into our target. Otherwise, if the
6258 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
6259 temp or an INIT_EXPR otherwise. */
6262 {
6267 }
6269 {
6271 complain));
6275 }
6276 }
6280 {
6281 tree to = stabilize_reference
6288 {
6289 /* Avoid copying empty classes. */
6294 }
6296 {
6299 }
6300 else
6301 {
6302 /* We must only copy the non-tail padding parts.
6303 Use __builtin_memcpy for the bitwise copy.
6304 FIXME fix 22488 so we can go back to using MODIFY_EXPR
6305 instead of an explicit call to memcpy. */
6315 {
6316 /* If we can't be sure about pointer alignment, a call
6317 to __builtin_memcpy is expanded as a call to memcpy, which
6318 is invalid with identical args. Otherwise it is
6319 expanded as a block move, which should be safe. */
6323 }
6332 }
6335 }
6336 /* FIXME handle trivial default constructor and destructor, too. */
6342 {
6343 tree t;
6349 /* Warn about deprecated virtual functions now, since we're about
6350 to throw away the decl. */
6360 else
6363 }
6364 else
6368 }
6370 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
6371 This function performs no overload resolution, conversion, or other
6372 high-level operations. */
6374 tree
6376 {
6377 tree fndecl;
6381 /* If this call might throw an exception, note that fact. */
6385 && cfun
6389 /* Check that arguments to builtin functions match the expectations. */
6396 /* Some built-in function calls will be evaluated at compile-time in
6397 fold (). */
6410 }
6414 /* Make an expression which yields the address of the Java interface
6415 method FN. This is achieved by generating a call to libjava's
6416 _Jv_LookupInterfaceMethodIdx(). */
6418 static tree
6420 {
6426 {
6430 java_iface_lookup_fn
6433 }
6435 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
6436 This is the first entry in the vtable. */
6438 tf_warning_or_error),
6439 integer_zero_node);
6441 /* Get the java.lang.Class pointer for the interface being called. */
6446 {
6448 iface);
6450 }
6454 /* Determine the itable index of FN. */
6457 {
6462 i++;
6463 }
6468 java_iface_lookup_fn);
6471 }
6473 /* Returns the value to use for the in-charge parameter when making a
6474 call to a function with the indicated NAME.
6476 FIXME:Can't we find a neater way to do this mapping? */
6478 tree
6480 {
6491 /* This function should only be called with one of the names listed
6492 above. */
6495 }
6497 /* Build a call to a constructor, destructor, or an assignment
6498 operator for INSTANCE, an expression with class type. NAME
6499 indicates the special member function to call; *ARGS are the
6500 arguments. ARGS may be NULL. This may change ARGS. BINFO
6501 indicates the base of INSTANCE that is to be passed as the `this'
6502 parameter to the member function called.
6504 FLAGS are the LOOKUP_* flags to use when processing the call.
6506 If NAME indicates a complete object constructor, INSTANCE may be
6507 NULL_TREE. In this case, the caller will call build_cplus_new to
6508 store the newly constructed object into a VAR_DECL. */
6510 tree
6513 {
6514 tree fns;
6515 /* The type of the subobject to be constructed or destroyed. */
6516 tree class_type;
6518 tree ret;
6527 {
6528 /* Resolve the name. */
6533 }
6539 /* Handle the special case where INSTANCE is NULL_TREE. */
6541 {
6544 }
6545 else
6546 {
6552 /* Convert to the base class, if necessary. */
6555 {
6557 /* For constructors and destructors, either the base is
6558 non-virtual, or it is virtual but we are doing the
6559 conversion from a constructor or destructor for the
6560 complete object. In either case, we can convert
6561 statically. */
6563 else
6564 /* However, for assignment operators, we must convert
6565 dynamically if the base is virtual. */
6568 }
6569 }
6575 /* When making a call to a constructor or destructor for a subobject
6576 that uses virtual base classes, pass down a pointer to a VTT for
6577 the subobject. */
6581 {
6582 tree vtt;
6583 tree sub_vtt;
6585 /* If the current function is a complete object constructor
6586 or destructor, then we fetch the VTT directly.
6587 Otherwise, we look it up using the VTT we were given. */
6593 current_vtt_parm,
6594 vtt);
6600 {
6603 }
6606 }
6611 complain);
6617 }
6619 /* Return the NAME, as a C string. The NAME indicates a function that
6620 is a member of TYPE. *FREE_P is set to true if the caller must
6621 free the memory returned.
6623 Rather than go through all of this, we should simply set the names
6624 of constructors and destructors appropriately, and dispense with
6625 ctor_identifier, dtor_identifier, etc. */
6629 {
6632 /* Assume that we will not allocate memory. */
6634 /* Constructors and destructors are special. */
6636 {
6637 pretty_name
6639 /* For a destructor, add the '~'. */
6643 {
6645 /* Remember that we need to free the memory allocated. */
6647 }
6648 }
6650 {
6653 TFF_PLAIN_IDENTIFIER),
6654 NULL);
6655 /* Remember that we need to free the memory allocated. */
6657 }
6658 else
6662 }
6664 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
6665 be set, upon return, to the function called. ARGS may be NULL.
6666 This may change ARGS. */
6668 tree
6672 {
6676 tree access_binfo;
6677 tree optype;
6679 tree instance_ptr;
6680 tree name;
6683 tree call;
6684 tree fn;
6687 tree orig_instance;
6688 tree orig_fns;
6694 /* We don't know what function we're going to call, yet. */
6703 {
6707 }
6712 /* Dismantle the baselink to collect all the information we need. */
6719 {
6723 }
6734 {
6739 }
6742 /* Under DR 147 A::A() is an invalid constructor call,
6743 not a functional cast. */
6745 {
6755 complain);
6757 }
6759 /* Figure out whether to skip the first argument for the error
6760 message we will display to users if an error occurs. We don't
6761 want to display any compiler-generated arguments. The "this"
6762 pointer hasn't been added yet. However, we must remove the VTT
6763 pointer if this is a call to a base-class constructor or
6764 destructor. */
6767 {
6768 /* Callers should explicitly indicate whether they want to construct
6769 the complete object or just the part without virtual bases. */
6771 /* Similarly for destructors. */
6773 /* Remove the VTT pointer, if present. */
6777 }
6779 /* Process the argument list. */
6781 {
6785 }
6789 /* It's OK to call destructors and constructors on cv-qualified objects.
6790 Therefore, convert the INSTANCE_PTR to the unqualified type, if
6791 necessary. */
6794 {
6798 }
6804 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6807 /* If CONSTRUCTOR_IS_DIRECT_INIT is set, this was a T{ } form
6808 initializer, not T({ }). */
6812 {
6819 }
6820 else
6821 {
6825 }
6830 {
6832 {
6839 else
6840 {
6843 tree arglist;
6854 }
6856 }
6858 }
6859 else
6860 {
6863 {
6866 tree arglist;
6869 {
6875 arglist);
6879 }
6881 }
6882 else
6883 {
6892 /* This is not an error, it is runtime undefined
6893 behavior. */
6895 "pure virtual %q#D called from constructor"
6897 fn);
6901 {
6904 fn);
6906 }
6907 else
6908 {
6912 /* Now we know what function is being called. */
6915 /* Build the actual CALL_EXPR. */
6917 /* In an expression of the form `a->f()' where `f' turns
6918 out to be a static member function, `a' is
6919 none-the-less evaluated. */
6928 /* An explicit call of the form "x->~X()" has type
6929 "void". However, on platforms where destructors
6930 return "this" (i.e., those where
6931 targetm.cxx.cdtor_returns_this is true), such calls
6932 will appear to have a return value of pointer type
6933 to the low-level call machinery. We do not want to
6934 change the low-level machinery, since we want to be
6935 able to optimize "delete f()" on such platforms as
6936 "operator delete(~X(f()))" (rather than generating
6937 "t = f(), ~X(t), operator delete (t)"). */
6939 }
6940 }
6941 }
6944 {
6950 {
6953 }
6956 call = (build_min_non_dep_call_vec
6960 orig_args));
6964 }
6966 /* Free all the conversions we allocated. */
6973 }
6975 /* Returns true iff standard conversion sequence ICS1 is a proper
6976 subsequence of ICS2. */
6978 static bool
6980 {
6981 /* We can assume that a conversion of the same code
6982 between the same types indicates a subsequence since we only get
6983 here if the types we are converting from are the same. */
6990 {
7000 /* At this point, ICS1 cannot be a proper subsequence of
7001 ICS2. We can get a USER_CONV when we are comparing the
7002 second standard conversion sequence of two user conversion
7003 sequences. */
7013 }
7014 }
7016 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
7017 be any _TYPE nodes. */
7019 bool
7021 {
7025 /* We only allow proper derivation here. The DERIVED_FROM_P macro
7026 considers every class derived from itself. */
7029 }
7031 /* We build the ICS for an implicit object parameter as a pointer
7032 conversion sequence. However, such a sequence should be compared
7033 as if it were a reference conversion sequence. If ICS is the
7034 implicit conversion sequence for an implicit object parameter,
7035 modify it accordingly. */
7037 static void
7039 {
7041 {
7042 /* [over.match.funcs]
7044 For non-static member functions, the type of the
7045 implicit object parameter is "reference to cv X"
7046 where X is the class of which the function is a
7047 member and cv is the cv-qualification on the member
7048 function declaration. */
7050 tree reference_type;
7052 /* The `this' parameter is a pointer to a class type. Make the
7053 implicit conversion talk about a reference to that same class
7054 type. */
7067 }
7068 }
7070 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
7071 and return the initial reference binding conversion. Otherwise,
7072 leave *ICS unchanged and return NULL. */
7076 {
7078 {
7083 }
7086 }
7088 /* Compare two implicit conversion sequences according to the rules set out in
7089 [over.ics.rank]. Return values:
7091 1: ics1 is better than ics2
7092 -1: ics2 is better than ics1
7093 0: ics1 and ics2 are indistinguishable */
7095 static int
7097 {
7098 tree from_type1;
7099 tree from_type2;
7100 tree to_type1;
7101 tree to_type2;
7108 /* REF_BINDING is nonzero if the result of the conversion sequence
7109 is a reference type. In that case REF_CONV is the reference
7110 binding conversion. */
7114 /* Handle implicit object parameters. */
7118 /* Handle reference parameters. */
7122 /* List-initialization sequence L1 is a better conversion sequence than
7123 list-initialization sequence L2 if L1 converts to
7124 std::initializer_list<X> for some X and L2 does not. */
7130 /* [over.ics.rank]
7132 When comparing the basic forms of implicit conversion sequences (as
7133 defined in _over.best.ics_)
7135 --a standard conversion sequence (_over.ics.scs_) is a better
7136 conversion sequence than a user-defined conversion sequence
7137 or an ellipsis conversion sequence, and
7139 --a user-defined conversion sequence (_over.ics.user_) is a
7140 better conversion sequence than an ellipsis conversion sequence
7141 (_over.ics.ellipsis_). */
7151 {
7152 /* Both ICS are bad. We try to make a decision based on what would
7153 have happened if they'd been good. This is not an extension,
7154 we'll still give an error when we build up the call; this just
7155 helps us give a more helpful error message. */
7164 /* We couldn't make up our minds; try to figure it out below. */
7165 }
7168 /* Both conversions are ellipsis conversions. */
7171 /* User-defined conversion sequence U1 is a better conversion sequence
7172 than another user-defined conversion sequence U2 if they contain the
7173 same user-defined conversion operator or constructor and if the sec-
7174 ond standard conversion sequence of U1 is better than the second
7175 standard conversion sequence of U2. */
7177 /* Handle list-conversion with the same code even though it isn't always
7178 ranked as a user-defined conversion and it doesn't have a second
7179 standard conversion sequence; it will still have the desired effect.
7180 Specifically, we need to do the reference binding comparison at the
7181 end of this function. */
7184 {
7200 {
7203 }
7204 else
7205 {
7206 /* For ambiguous or aggregate conversions, use the target type as
7207 a proxy for the conversion function. */
7210 }
7212 /* We can just fall through here, after setting up
7213 FROM_TYPE1 and FROM_TYPE2. */
7216 }
7217 else
7218 {
7222 /* We're dealing with two standard conversion sequences.
7224 [over.ics.rank]
7226 Standard conversion sequence S1 is a better conversion
7227 sequence than standard conversion sequence S2 if
7229 --S1 is a proper subsequence of S2 (comparing the conversion
7230 sequences in the canonical form defined by _over.ics.scs_,
7231 excluding any Lvalue Transformation; the identity
7232 conversion sequence is considered to be a subsequence of
7233 any non-identity conversion sequence */
7244 }
7246 /* One sequence can only be a subsequence of the other if they start with
7247 the same type. They can start with different types when comparing the
7248 second standard conversion sequence in two user-defined conversion
7249 sequences. */
7251 {
7256 }
7258 /* [over.ics.rank]
7260 Or, if not that,
7262 --the rank of S1 is better than the rank of S2 (by the rules
7263 defined below):
7265 Standard conversion sequences are ordered by their ranks: an Exact
7266 Match is a better conversion than a Promotion, which is a better
7267 conversion than a Conversion.
7269 Two conversion sequences with the same rank are indistinguishable
7270 unless one of the following rules applies:
7272 --A conversion that does not a convert a pointer, pointer to member,
7273 or std::nullptr_t to bool is better than one that does.
7275 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
7276 so that we do not have to check it explicitly. */
7285 /* A conversion from scalar arithmetic type to complex is worse than a
7286 conversion between scalar arithmetic types. */
7293 {
7296 else
7298 }
7304 {
7309 }
7310 /* The rules for pointers to members A::* are just like the rules
7311 for pointers A*, except opposite: if B is derived from A then
7312 A::* converts to B::*, not vice versa. For that reason, we
7313 switch the from_ and to_ variables here. */
7320 {
7325 }
7330 {
7331 /* This was one of the pointer or pointer-like conversions.
7333 [over.ics.rank]
7335 --If class B is derived directly or indirectly from class A,
7336 conversion of B* to A* is better than conversion of B* to
7337 void*, and conversion of A* to void* is better than
7338 conversion of B* to void*. */
7341 {
7343 deref_from_type2))
7346 deref_from_type1))
7348 }
7351 {
7353 {
7355 {
7357 deref_to_type1))
7359 }
7360 /* We know that DEREF_TO_TYPE1 is `void' here. */
7362 deref_to_type2))
7364 }
7365 }
7368 {
7369 /* [over.ics.rank]
7371 --If class B is derived directly or indirectly from class A
7372 and class C is derived directly or indirectly from B,
7374 --conversion of C* to B* is better than conversion of C* to
7375 A*,
7377 --conversion of B* to A* is better than conversion of C* to
7378 A* */
7380 {
7382 deref_to_type2))
7385 deref_to_type1))
7387 }
7389 {
7391 deref_from_type1))
7394 deref_from_type2))
7396 }
7397 }
7398 }
7401 {
7404 /* [over.ics.rank]
7406 --binding of an expression of type C to a reference of type
7407 B& is better than binding an expression of type C to a
7408 reference of type A&
7410 --conversion of C to B is better than conversion of C to A, */
7413 {
7418 }
7419 }
7422 {
7425 /* [over.ics.rank]
7427 --binding of an expression of type B to a reference of type
7428 A& is better than binding an expression of type C to a
7429 reference of type A&,
7431 --conversion of B to A is better than conversion of C to A */
7434 {
7439 }
7440 }
7442 /* [over.ics.rank]
7444 --S1 and S2 differ only in their qualification conversion and yield
7445 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
7446 qualification signature of type T1 is a proper subset of the cv-
7447 qualification signature of type T2 */
7451 {
7455 }
7457 /* [over.ics.rank]
7459 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
7460 to an implicit object parameter, and either S1 binds an lvalue reference
7461 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
7462 reference to an rvalue and S2 binds an lvalue reference
7463 (C++0x draft standard, 13.3.3.2)
7465 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
7466 types to which the references refer are the same type except for
7467 top-level cv-qualifiers, and the type to which the reference
7468 initialized by S2 refers is more cv-qualified than the type to
7469 which the reference initialized by S1 refers */
7472 {
7476 {
7481 }
7486 }
7488 /* Neither conversion sequence is better than the other. */
7490 }
7492 /* The source type for this standard conversion sequence. */
7494 static tree
7496 {
7498 {
7503 }
7505 }
7507 /* Note a warning about preferring WINNER to LOSER. We do this by storing
7508 a pointer to LOSER and re-running joust to produce the warning if WINNER
7509 is actually used. */
7511 static void
7513 {
7519 }
7521 /* Compare two candidates for overloading as described in
7522 [over.match.best]. Return values:
7524 1: cand1 is better than cand2
7525 -1: cand2 is better than cand1
7526 0: cand1 and cand2 are indistinguishable */
7528 static int
7530 {
7536 /* Candidates that involve bad conversions are always worse than those
7537 that don't. */
7543 /* If we have two pseudo-candidates for conversions to the same type,
7544 or two candidates for the same function, arbitrarily pick one. */
7549 /* a viable function F1
7550 is defined to be a better function than another viable function F2 if
7551 for all arguments i, ICSi(F1) is not a worse conversion sequence than
7552 ICSi(F2), and then */
7554 /* for some argument j, ICSj(F1) is a better conversion sequence than
7555 ICSj(F2) */
7557 /* For comparing static and non-static member functions, we ignore
7558 the implicit object parameter of the non-static function. The
7559 standard says to pretend that the static function has an object
7560 parm, but that won't work with operator overloading. */
7563 {
7571 else
7572 {
7575 }
7576 }
7579 {
7585 {
7598 {
7605 else
7610 {
7614 }
7615 else
7617 }
7620 {
7623 }
7625 }
7626 }
7628 /* warn about confusing overload resolution for user-defined conversions,
7629 either between a constructor and a conversion op, or between two
7630 conversion ops. */
7634 {
7640 else
7643 /* We don't want to complain about `X::operator T1 ()'
7644 beating `X::operator T2 () const', when T2 is a no less
7645 cv-qualified version of T1. */
7648 {
7653 {
7656 }
7659 }
7660 else
7666 {
7673 {
7675 }
7676 }
7677 else
7679 }
7684 /* or, if not that,
7685 F1 is a non-template function and F2 is a template function
7686 specialization. */
7693 /* or, if not that,
7694 F1 and F2 are template functions and the function template for F1 is
7695 more specialized than the template for F2 according to the partial
7696 ordering rules. */
7699 {
7700 winner = more_specialized_fn
7703 /* [temp.func.order]: The presence of unused ellipsis and default
7704 arguments has no effect on the partial ordering of function
7705 templates. add_function_candidate() will not have
7706 counted the "this" argument for constructors. */
7710 }
7712 /* or, if not that,
7713 the context is an initialization by user-defined conversion (see
7714 _dcl.init_ and _over.match.user_) and the standard conversion
7715 sequence from the return type of F1 to the destination type (i.e.,
7716 the type of the entity being initialized) is a better conversion
7717 sequence than the standard conversion sequence from the return type
7718 of F2 to the destination type. */
7721 {
7725 }
7727 /* Check whether we can discard a builtin candidate, either because we
7728 have two identical ones or matching builtin and non-builtin candidates.
7730 (Pedantically in the latter case the builtin which matched the user
7731 function should not be added to the overload set, but we spot it here.
7733 [over.match.oper]
7734 ... the builtin candidates include ...
7735 - do not have the same parameter type list as any non-template
7736 non-member candidate. */
7740 {
7746 {
7748 /* Two built-in candidates; arbitrarily pick one. */
7751 /* cand1 is built-in; prefer cand2. */
7753 else
7754 /* cand2 is built-in; prefer cand1. */
7756 }
7757 }
7759 /* If the two function declarations represent the same function (this can
7760 happen with declarations in multiple scopes and arg-dependent lookup),
7761 arbitrarily choose one. But first make sure the default args we're
7762 using match. */
7765 {
7772 {
7773 /* Don't crash if the fn is variadic. */
7778 }
7786 {
7789 {
7791 {
7798 }
7799 else
7802 }
7805 }
7808 }
7810 tweak:
7812 /* Extension: If the worst conversion for one candidate is worse than the
7813 worst conversion for the other, take the first. */
7815 {
7820 {
7825 }
7831 {
7832 /* Don't choose a deleted function over ambiguity. */
7836 {
7838 "ISO C++ says that these are ambiguous, even "
7839 "though the worst conversion for the first is better than "
7843 }
7844 else
7847 }
7848 }
7852 }
7854 /* Given a list of candidates for overloading, find the best one, if any.
7855 This algorithm has a worst case of O(2n) (winner is last), and a best
7856 case of O(n/2) (totally ambiguous); much better than a sorting
7857 algorithm. */
7861 {
7866 /* Walk through the list once, comparing each current champ to the next
7867 candidate, knocking out a candidate or two with each comparison. */
7870 {
7874 else
7875 {
7877 {
7882 }
7883 else
7884 {
7887 }
7890 }
7891 }
7893 /* Make sure the champ is better than all the candidates it hasn't yet
7894 been compared to. */
7897 challenger != champ
7900 {
7904 }
7907 }
7909 /* Returns nonzero if things of type FROM can be converted to TO. */
7911 bool
7913 {
7915 }
7917 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
7919 bool
7921 {
7926 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7930 flags);
7933 /* Free all the conversions we allocated. */
7937 }
7939 /* Like can_convert_arg, but allows dubious conversions as well. */
7941 bool
7943 {
7947 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7949 /* Try to perform the conversion. */
7951 flags);
7952 /* Free all the conversions we allocated. */
7956 }
7958 /* Convert EXPR to TYPE. Return the converted expression.
7960 Note that we allow bad conversions here because by the time we get to
7961 this point we are committed to doing the conversion. If we end up
7962 doing a bad conversion, convert_like will complain. */
7964 tree
7966 {
7973 /* Get the high-water mark for the CONVERSION_OBSTACK. */
7978 flags);
7981 {
7983 {
7984 /* If expr has unknown type, then it is an overloaded function.
7985 Call instantiate_type to get good error messages. */
7990 else
7992 }
7994 }
7996 {
7997 /* In a template, we are only concerned about determining the
7998 type of non-dependent expressions, so we do not have to
7999 perform the actual conversion. */
8002 }
8003 else
8006 /* Free all the conversions we allocated. */
8010 }
8012 tree
8014 {
8016 }
8018 /* Convert EXPR to TYPE (as a direct-initialization) if that is
8019 permitted. If the conversion is valid, the converted expression is
8020 returned. Otherwise, NULL_TREE is returned, except in the case
8021 that TYPE is a class type; in that case, an error is issued. If
8022 C_CAST_P is true, then this direction initialization is taking
8023 place as part of a static_cast being attempted as part of a C-style
8024 cast. */
8026 tree
8028 tree expr,
8030 tsubst_flags_t complain)
8031 {
8037 /* [dcl.init]
8039 If the destination type is a (possibly cv-qualified) class type:
8041 -- If the initialization is direct-initialization ...,
8042 constructors are considered. ... If no constructor applies, or
8043 the overload resolution is ambiguous, the initialization is
8044 ill-formed. */
8046 {
8052 }
8054 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8058 c_cast_p,
8059 LOOKUP_NORMAL);
8062 else
8065 c_cast_p,
8066 complain);
8068 /* Free all the conversions we allocated. */
8072 }
8074 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
8075 is being bound to a temporary. Create and return a new VAR_DECL
8076 with the indicated TYPE; this variable will store the value to
8077 which the reference is bound. */
8079 tree
8081 {
8082 tree var;
8084 /* Create the variable. */
8087 /* Register the variable. */
8089 {
8090 /* Namespace-scope or local static; give it a mangled name. */
8091 tree name;
8098 }
8099 else
8100 /* Create a new cleanup level if necessary. */
8104 }
8106 /* EXPR is the initializer for a variable DECL of reference or
8107 std::initializer_list type. Create, push and return a new VAR_DECL
8108 for the initializer so that it will live as long as DECL. Any
8109 cleanup for the new variable is returned through CLEANUP, and the
8110 code to initialize the new variable is returned through INITP. */
8112 tree
8114 {
8115 tree init;
8116 tree type;
8117 tree var;
8119 /* Create the temporary variable. */
8123 /* If the rvalue is the result of a function call it will be
8124 a TARGET_EXPR. If it is some other construct (such as a
8125 member access expression where the underlying object is
8126 itself the result of a function call), turn it into a
8127 TARGET_EXPR here. It is important that EXPR be a
8128 TARGET_EXPR below since otherwise the INIT_EXPR will
8129 attempt to make a bitwise copy of EXPR to initialize
8130 VAR. */
8134 /* If the initializer is constant, put it in DECL_INITIAL so we get
8135 static initialization and use in constant expressions. */
8138 {
8140 {
8141 /* 5.19 says that a constant expression can include an
8142 lvalue-rvalue conversion applied to "a glvalue of literal type
8143 that refers to a non-volatile temporary object initialized
8144 with a constant expression". Rather than try to communicate
8145 that this VAR_DECL is a temporary, just mark it constexpr.
8147 Currently this is only useful for initializer_list temporaries,
8148 since reference vars can't appear in constant expressions. */
8151 }
8154 }
8155 else
8156 /* Create the INIT_EXPR that will initialize the temporary
8157 variable. */
8160 {
8165 else
8168 /* We must be careful to destroy the temporary only
8169 after its initialization has taken place. If the
8170 initialization throws an exception, then the
8171 destructor should not be run. We cannot simply
8172 transform INIT into something like:
8174 (INIT, ({ CLEANUP_STMT; }))
8176 because emit_local_var always treats the
8177 initializer as a full-expression. Thus, the
8178 destructor would run too early; it would run at the
8179 end of initializing the reference variable, rather
8180 than at the end of the block enclosing the
8181 reference variable.
8183 The solution is to pass back a cleanup expression
8184 which the caller is responsible for attaching to
8185 the statement tree. */
8186 }
8187 else
8188 {
8192 static_aggregates);
8193 }
8197 }
8199 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
8200 initializing a variable of that TYPE. If DECL is non-NULL, it is
8201 the VAR_DECL being initialized with the EXPR. (In that case, the
8202 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
8203 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
8204 return, if *CLEANUP is no longer NULL, it will be an expression
8205 that should be pushed as a cleanup after the returned expression
8206 is used to initialize DECL.
8208 Return the converted expression. */
8210 tree
8212 tsubst_flags_t complain)
8213 {
8220 /* Get the high-water mark for the CONVERSION_OBSTACK. */
8224 LOOKUP_NORMAL);
8226 {
8228 {
8235 else
8239 }
8241 }
8243 /* If DECL is non-NULL, then this special rule applies:
8245 [class.temporary]
8247 The temporary to which the reference is bound or the temporary
8248 that is the complete object to which the reference is bound
8249 persists for the lifetime of the reference.
8251 The temporaries created during the evaluation of the expression
8252 initializing the reference, except the temporary to which the
8253 reference is bound, are destroyed at the end of the
8254 full-expression in which they are created.
8256 In that case, we store the converted expression into a new
8257 VAR_DECL in a new scope.
8259 However, we want to be careful not to create temporaries when
8260 they are not required. For example, given:
8262 struct B {};
8263 struct D : public B {};
8264 D f();
8265 const B& b = f();
8267 there is no need to copy the return value from "f"; we can just
8268 extend its lifetime. Similarly, given:
8270 struct S {};
8271 struct T { operator S(); };
8272 T t;
8273 const S& s = t;
8275 we can extend the lifetime of the return value of the conversion
8276 operator. */
8279 {
8280 tree var;
8281 tree base_conv_type;
8283 /* Skip over the REF_BIND. */
8285 /* If the next conversion is a BASE_CONV, skip that too -- but
8286 remember that the conversion was required. */
8288 {
8291 }
8292 else
8294 /* Perform the remainder of the conversion. */
8300 tf_warning_or_error);
8303 else
8304 {
8306 {
8307 tree init;
8309 /* Use its address to initialize the reference variable. */
8318 }
8319 else
8320 /* Take the address of EXPR. */
8322 /* If a BASE_CONV was required, perform it now. */
8324 expr = (perform_implicit_conversion
8326 tf_warning_or_error));
8328 }
8329 }
8330 else
8331 /* Perform the conversion. */
8334 /* Free all the conversions we allocated. */
8338 }
8340 /* Returns true iff TYPE is some variant of std::initializer_list. */
8342 bool
8344 {
8345 /* Look through typedefs. */
8352 }
8354 /* Returns true iff DECL is a list constructor: i.e. a constructor which
8355 will accept an argument list of a single std::initializer_list<T>. */
8357 bool
8359 {
8361 tree arg;
8373 /* There are more non-defaulted parms. */
8377 }