| blob | b2f9291139fdf103a2266a83423b0f3597a236a3 |
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 Free Software Foundation, Inc.
4 Contributed by Michael Tiemann (tiemann@cygnus.com) and
5 modified by Brendan Kehoe (brendan@cygnus.com).
7 This file is part of GCC.
9 GCC is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; either version 2, or (at your option)
12 any later version.
14 GCC is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
19 You should have received a copy of the GNU General Public License
20 along with GCC; see the file COPYING. If not, write to
21 the Free Software Foundation, 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
25 /* High-level class interface. */
49 #define convert_like(CONV, EXPR) \
50 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0)
51 #define convert_like_with_context(CONV, EXPR, FN, ARGNO) \
52 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0)
73 static void add_builtin_candidates
76 static void add_builtin_candidate
80 static void build_builtin_candidate
112 tree
114 {
127 }
129 /* Build a call to a member of an object. I.e., one that overloads
130 operator ()(), or is a pointer-to-function or pointer-to-method. */
132 static tree
134 {
135 tree instance;
141 {
142 /* If it's a field, try overloading operator (),
143 or calling if the field is a pointer-to-function. */
160 }
163 }
165 /* Returns nonzero iff the destructor name specified in NAME
166 (a BIT_NOT_EXPR) matches BASETYPE. The operand of NAME can take many
167 forms... */
169 bool
171 {
174 /* Just accept something we've already complained about. */
183 {
188 else
190 }
191 /* In the case of:
193 template <class T> struct S { ~S(); };
194 int i;
195 i.~S();
197 NAME will be a class template. */
200 else
206 }
208 /* Build a method call of the form `EXP->SCOPES::NAME (PARMS)'.
209 This is how virtual function calls are avoided. */
211 tree
213 {
214 /* Because this syntactic form does not allow
215 a pointer to a base class to be `stolen',
216 we need not protect the derived->base conversion
217 that happens here.
219 @@ But we do have to check access privileges later. */
228 {
231 }
237 {
240 }
241 else
244 /* Check the destructor call syntax. */
246 {
247 /* We can get here if someone writes their destructor call like
248 `obj.NS::~T()'; this isn't really a scoped method call, so hand
249 it off. */
257 /* Destructors can be "called" for simple types; see 5.2.4 and 12.4 Note
258 that explicit ~int is caught in the parser; this deals with typedefs
259 and template parms. */
261 {
267 }
268 }
271 {
274 }
279 {
283 }
288 {
289 /* Call to a destructor. */
291 {
296 sfk_complete_destructor,
299 }
301 /* Call to a method. */
304 }
306 }
308 /* We want the address of a function or method. We avoid creating a
309 pointer-to-member function. */
311 tree
313 {
316 /* We have to do these by hand to avoid real pointer to member
317 functions. */
319 {
320 tree addr;
329 /* Address of a static or external variable or function counts
330 as a constant */
335 }
336 else
340 }
342 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
343 POINTER_TYPE to those. Note, pointer to member function types
344 (TYPE_PTRMEMFUNC_P) must be handled by our callers. */
346 tree
348 {
351 tree tmp;
352 tree decl;
353 tree result_type;
354 tree fntype;
359 {
362 }
370 else
373 /* We check both the decl and the type; a function may be known not to
374 throw without being declared throw(). */
389 {
390 /* We invoke build_call directly for several library functions.
391 These may have been declared normally if we're building libgcc,
392 so we can't just check DECL_ARTIFICIAL. */
396 else
398 }
400 /* Don't pass empty class objects by value. This is useful
401 for tags in STL, which are used to control overload resolution.
402 We don't need to handle other cases of copying empty classes. */
407 {
411 }
420 }
422 /* Build something of the form ptr->method (args)
423 or object.method (args). This can also build
424 calls to constructors, and find friends.
426 Member functions always take their class variable
427 as a pointer.
429 INSTANCE is a class instance.
431 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
433 PARMS help to figure out what that NAME really refers to.
435 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
436 down to the real instance type to use for access checking. We need this
437 information to get protected accesses correct. This parameter is used
438 by build_member_call.
440 FLAGS is the logical disjunction of zero or more LOOKUP_
441 flags. See cp-tree.h for more info.
443 If this is all OK, calls build_function_call with the resolved
444 member function.
446 This function must also handle being called to perform
447 initialization, promotion/coercion of arguments, and
448 instantiation of default parameters.
450 Note that NAME may refer to an instance variable name. If
451 `operator()()' is defined for the type of that field, then we return
452 that result. */
454 #ifdef GATHER_STATISTICS
456 #endif
458 tree
461 {
462 tree fn;
463 tree object_type;
467 #ifdef GATHER_STATISTICS
468 n_build_method_call++;
469 #endif
487 {
488 tree instance_ptr;
494 error
505 }
508 {
514 }
517 {
521 }
528 else
532 {
536 }
538 /* If the name could not be found, issue an error. */
540 {
543 }
549 template_args);
555 }
557 /* New overloading code. */
560 /* The FUNCTION_DECL that will be called if this candidate is
561 selected by overload resolution. */
562 tree fn;
563 /* The arguments to use when calling this function. */
564 tree args;
565 /* The implicit conversion sequences for each of the arguments to
566 FN. */
567 tree convs;
568 /* If FN is a user-defined conversion, the standard conversion
569 sequence from the type returned by FN to the desired destination
570 type. */
571 tree second_conv;
573 /* If FN is a member function, the binfo indicating the path used to
574 qualify the name of FN at the call site. This path is used to
575 determine whether or not FN is accessible if it is selected by
576 overload resolution. The DECL_CONTEXT of FN will always be a
577 (possibly improper) base of this binfo. */
578 tree access_path;
579 /* If FN is a non-static member function, the binfo indicating the
580 subobject to which the `this' pointer should be converted if FN
581 is selected by overload resolution. The type pointed to the by
582 the `this' pointer must correspond to the most derived class
583 indicated by the CONVERSION_PATH. */
584 tree conversion_path;
586 tree warnings;
588 };
590 #define IDENTITY_RANK 0
591 #define EXACT_RANK 1
592 #define PROMO_RANK 2
593 #define STD_RANK 3
594 #define PBOOL_RANK 4
595 #define USER_RANK 5
596 #define ELLIPSIS_RANK 6
597 #define BAD_RANK 7
599 #define ICS_RANK(NODE) \
600 (ICS_BAD_FLAG (NODE) ? BAD_RANK \
601 : ICS_ELLIPSIS_FLAG (NODE) ? ELLIPSIS_RANK \
602 : ICS_USER_FLAG (NODE) ? USER_RANK \
603 : ICS_STD_RANK (NODE))
605 #define ICS_STD_RANK(NODE) TREE_COMPLEXITY (NODE)
607 #define ICS_USER_FLAG(NODE) TREE_LANG_FLAG_0 (NODE)
608 #define ICS_ELLIPSIS_FLAG(NODE) TREE_LANG_FLAG_1 (NODE)
609 #define ICS_THIS_FLAG(NODE) TREE_LANG_FLAG_2 (NODE)
610 #define ICS_BAD_FLAG(NODE) TREE_LANG_FLAG_3 (NODE)
612 /* In a REF_BIND or a BASE_CONV, this indicates that a temporary
613 should be created to hold the result of the conversion. */
614 #define NEED_TEMPORARY_P(NODE) TREE_LANG_FLAG_4 (NODE)
616 #define USER_CONV_CAND(NODE) WRAPPER_ZC (TREE_OPERAND (NODE, 1))
617 #define USER_CONV_FN(NODE) (USER_CONV_CAND (NODE)->fn)
619 bool
621 {
622 /* [conv.ptr]
624 A null pointer constant is an integral constant expression
625 (_expr.const_) rvalue of integer type that evaluates to zero. */
630 }
633 /* Returns nonzero if PARMLIST consists of only default parms and/or
634 ellipsis. */
636 bool
638 {
644 }
646 static tree
648 {
649 tree t;
652 /* We can't use buildl1 here because CODE could be USER_CONV, which
653 takes two arguments. In that case, the caller is responsible for
654 filling in the second argument. */
660 {
675 }
680 }
682 /* If T is a REFERENCE_TYPE return the type to which T refers.
683 Otherwise, return T itself. */
685 static tree
687 {
691 }
693 tree
695 {
699 }
701 /* Returns the standard conversion path (see [conv]) from type FROM to type
702 TO, if any. For proper handling of null pointer constants, you must
703 also pass the expression EXPR to convert from. */
705 static tree
707 {
709 tree conv;
715 {
718 }
724 {
729 }
737 {
741 }
743 {
747 }
751 /* Allow conversion between `__complex__' data types */
753 {
754 /* The standard conversion sequence to convert FROM to TO is
755 the standard conversion sequence to perform componentwise
756 conversion. */
757 tree part_conv = standard_conversion
761 {
764 }
765 else
769 }
776 {
778 }
781 {
782 /* For backwards brain damage compatibility, allow interconversion of
783 pointers and integers with a pedwarn. */
786 }
789 {
790 /* For backwards brain damage compatibility, allow interconversion of
791 enums and integers with a pedwarn. */
794 }
796 {
802 ;
805 {
806 from = build_pointer_type
810 }
812 {
817 && (same_type_ignoring_top_level_qualifiers_p
820 {
823 }
824 }
827 {
829 {
830 from =
835 }
836 }
843 /* converting from string constant to char *. */
846 {
849 }
850 else
854 }
856 {
874 }
876 {
885 }
886 /* We don't check for ENUMERAL_TYPE here because there are no standard
887 conversions to enum type. */
890 {
895 /* Give this a better rank if it's a promotion. */
899 }
902 {
906 /* The derived-to-base conversion indicates the initialization
907 of a parameter with base type from an object of a derived
908 type. A temporary object is created to hold the result of
909 the conversion. */
911 }
912 else
916 }
918 /* Returns nonzero if T1 is reference-related to T2. */
920 static bool
922 {
926 /* [dcl.init.ref]
928 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
929 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
930 of T2. */
934 }
936 /* Returns nonzero if T1 is reference-compatible with T2. */
938 static bool
940 {
941 /* [dcl.init.ref]
943 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
944 reference-related to T2 and cv1 is the same cv-qualification as,
945 or greater cv-qualification than, cv2. */
948 }
950 /* Determine whether or not the EXPR (of class type S) can be
951 converted to T as in [over.match.ref]. */
953 static tree
955 {
956 tree conversions;
957 tree arglist;
958 tree conv;
959 tree reference_type;
968 /* [over.match.ref]
970 Assuming that "cv1 T" is the underlying type of the reference
971 being initialized, and "cv S" is the type of the initializer
972 expression, with S a class type, the candidate functions are
973 selected as follows:
975 --The conversion functions of S and its base classes are
976 considered. Those that are not hidden within S and yield type
977 "reference to cv2 T2", where "cv1 T" is reference-compatible
978 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
980 The argument list has one argument, which is the initializer
981 expression. */
985 /* Conceptually, we should take the address of EXPR and put it in
986 the argument list. Unfortunately, however, that can result in
987 error messages, which we should not issue now because we are just
988 trying to find a conversion operator. Therefore, we use NULL,
989 cast to the appropriate type. */
997 {
1001 {
1007 /* If this is a template function, try to get an exact
1008 match. */
1010 {
1013 NULL_TREE,
1014 arglist,
1015 reference_type,
1018 LOOKUP_NORMAL,
1019 DEDUCE_CONV);
1022 {
1023 /* Now, see if the conversion function really returns
1024 an lvalue of the appropriate type. From the
1025 point of view of unification, simply returning an
1026 rvalue of the right type is good enough. */
1031 {
1034 }
1035 }
1036 }
1042 LOOKUP_NORMAL);
1045 /* Build a standard conversion sequence indicating the
1046 binding from the reference type returned by the
1047 function to the desired REFERENCE_TYPE. */
1048 cand->second_conv
1049 = (direct_reference_binding
1053 NULL_TREE)));
1054 }
1056 }
1059 /* If none of the conversion functions worked out, let our caller
1060 know. */
1068 /* Now that we know that this is the function we're going to use fix
1069 the dummy first argument. */
1074 /* Build a user-defined conversion sequence representing the
1075 conversion. */
1081 /* Merge it with the standard conversion sequence from the
1082 conversion function's return type to the desired type. */
1089 }
1091 /* A reference of the indicated TYPE is being bound directly to the
1092 expression represented by the implicit conversion sequence CONV.
1093 Return a conversion sequence for this binding. */
1095 static tree
1097 {
1098 tree t;
1106 /* [over.ics.rank]
1108 When a parameter of reference type binds directly
1109 (_dcl.init.ref_) to an argument expression, the implicit
1110 conversion sequence is the identity conversion, unless the
1111 argument expression has a type that is a derived class of the
1112 parameter type, in which case the implicit conversion sequence is
1113 a derived-to-base Conversion.
1115 If the parameter binds directly to the result of applying a
1116 conversion function to the argument expression, the implicit
1117 conversion sequence is a user-defined conversion sequence
1118 (_over.ics.user_), with the second standard conversion sequence
1119 either an identity conversion or, if the conversion function
1120 returns an entity of a type that is a derived class of the
1121 parameter type, a derived-to-base conversion. */
1123 {
1124 /* Represent the derived-to-base conversion. */
1126 /* We will actually be binding to the base-class subobject in
1127 the derived class, so we mark this conversion appropriately.
1128 That way, convert_like knows not to generate a temporary. */
1130 }
1132 }
1134 /* Returns the conversion path from type FROM to reference type TO for
1135 purposes of reference binding. For lvalue binding, either pass a
1136 reference type to FROM or an lvalue expression to EXPR. If the
1137 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1138 the conversion returned. */
1140 static tree
1142 {
1151 {
1156 }
1159 {
1160 /* Anything with reference type is an lvalue. */
1163 }
1167 /* Figure out whether or not the types are reference-related and
1168 reference compatible. We have do do this after stripping
1169 references from FROM. */
1174 {
1175 /* [dcl.init.ref]
1177 If the initializer expression
1179 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1180 is reference-compatible with "cv2 T2,"
1182 the reference is bound directly to the initializer exprssion
1183 lvalue. */
1188 /* For the purposes of overload resolution, we ignore the fact
1189 this expression is a bitfield. (In particular,
1190 [over.ics.ref] says specifically that a function with a
1191 non-const reference parameter is viable even if the
1192 argument is a bitfield.)
1194 However, when we actually call the function we must create
1195 a temporary to which to bind the reference. If the
1196 reference is volatile, or isn't const, then we cannot make
1197 a temporary, so we just issue an error when the conversion
1198 actually occurs. */
1201 }
1203 {
1204 /* [dcl.init.ref]
1206 If the initializer exprsesion
1208 -- has a class type (i.e., T2 is a class type) can be
1209 implicitly converted to an lvalue of type "cv3 T3," where
1210 "cv1 T1" is reference-compatible with "cv3 T3". (this
1211 conversion is selected by enumerating the applicable
1212 conversion functions (_over.match.ref_) and choosing the
1213 best one through overload resolution. (_over.match_).
1215 the reference is bound to the lvalue result of the conversion
1216 in the second case. */
1220 }
1222 /* From this point on, we conceptually need temporaries, even if we
1223 elide them. Only the cases above are "direct bindings". */
1227 /* [over.ics.rank]
1229 When a parameter of reference type is not bound directly to an
1230 argument expression, the conversion sequence is the one required
1231 to convert the argument expression to the underlying type of the
1232 reference according to _over.best.ics_. Conceptually, this
1233 conversion sequence corresponds to copy-initializing a temporary
1234 of the underlying type with the argument expression. Any
1235 difference in top-level cv-qualification is subsumed by the
1236 initialization itself and does not constitute a conversion. */
1238 /* [dcl.init.ref]
1240 Otherwise, the reference shall be to a non-volatile const type. */
1244 /* [dcl.init.ref]
1246 If the initializer expression is an rvalue, with T2 a class type,
1247 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1248 is bound in one of the following ways:
1250 -- The reference is bound to the object represented by the rvalue
1251 or to a sub-object within that object.
1253 -- ...
1255 We use the first alternative. The implicit conversion sequence
1256 is supposed to be same as we would obtain by generating a
1257 temporary. Fortunately, if the types are reference compatible,
1258 then this is either an identity conversion or the derived-to-base
1259 conversion, just as for direct binding. */
1261 {
1264 }
1266 /* [dcl.init.ref]
1268 Otherwise, a temporary of type "cv1 T1" is created and
1269 initialized from the initializer expression using the rules for a
1270 non-reference copy initialization. If T1 is reference-related to
1271 T2, cv1 must be the same cv-qualification as, or greater
1272 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1281 /* This reference binding, unlike those above, requires the
1282 creation of a temporary. */
1286 }
1288 /* Returns the implicit conversion sequence (see [over.ics]) from type FROM
1289 to type TO. The optional expression EXPR may affect the conversion.
1290 FLAGS are the usual overloading flags. Only LOOKUP_NO_CONVERSION is
1291 significant. */
1293 static tree
1295 {
1296 tree conv;
1298 /* Resolve expressions like `A::p' that we thought might become
1299 pointers-to-members. */
1301 {
1304 }
1312 else
1322 {
1325 cand = build_user_type_conversion_1
1330 /* We used to try to bind a reference to a temporary here, but that
1331 is now handled by the recursive call to this function at the end
1332 of reference_binding. */
1334 }
1337 }
1339 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1340 functions. */
1346 {
1360 }
1362 /* Create an overload candidate for the function or method FN called with
1363 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1364 to implicit_conversion.
1366 CTYPE, if non-NULL, is the type we want to pretend this function
1367 comes from for purposes of overload resolution. */
1374 {
1377 tree convs;
1379 tree orig_arglist;
1382 /* Built-in functions that haven't been declared don't really
1383 exist. */
1387 /* The `this', `in_chrg' and VTT arguments to constructors are not
1388 considered in overload resolution. */
1390 {
1394 }
1395 else
1401 /* 13.3.2 - Viable functions [over.match.viable]
1402 First, to be a viable function, a candidate function shall have enough
1403 parameters to agree in number with the arguments in the list.
1405 We need to check this first; otherwise, checking the ICSes might cause
1406 us to produce an ill-formed template instantiation. */
1410 {
1414 }
1419 /* Make sure there are default args for the rest of the parms. */
1426 /* Second, for F to be a viable function, there shall exist for each
1427 argument an implicit conversion sequence that converts that argument
1428 to the corresponding parameter of F. */
1434 {
1437 tree t;
1447 {
1450 /* The type of the implicit object parameter ('this') for
1451 overload resolution is not always the same as for the
1452 function itself; conversion functions are considered to
1453 be members of the class being converted, and functions
1454 introduced by a using-declaration are considered to be
1455 members of the class that uses them.
1457 Since build_over_call ignores the ICS for the `this'
1458 parameter, we can just change the parm type. */
1460 {
1461 parmtype
1465 }
1468 }
1469 else
1470 {
1473 }
1480 {
1483 }
1491 }
1493 out:
1496 }
1498 /* Create an overload candidate for the conversion function FN which will
1499 be invoked for expression OBJ, producing a pointer-to-function which
1500 will in turn be called with the argument list ARGLIST, and add it to
1501 CANDIDATES. FLAGS is passed on to implicit_conversion.
1503 Actually, we don't really care about FN; we care about the type it
1504 converts to. There may be multiple conversion functions that will
1505 convert to that type, and we rely on build_user_type_conversion_1 to
1506 choose the best one; so when we create our candidate, we record the type
1507 instead of the function. */
1512 {
1528 /* Don't bother looking up the same type twice. */
1533 {
1536 tree t;
1544 else
1545 {
1548 }
1563 }
1573 }
1575 static void
1579 {
1590 {
1596 {
1598 /* We need something for printing the candidate. */
1600 }
1604 }
1606 /* For COND_EXPR we rearranged the arguments; undo that now. */
1608 {
1614 else
1616 }
1621 viable);
1622 }
1624 static bool
1626 {
1628 }
1630 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1632 static bool
1634 {
1635 /* [over.built]
1637 In this section, the term promoted integral type is used to refer
1638 to those integral types which are preserved by integral promotion
1639 (including e.g. int and long but excluding e.g. char).
1640 Similarly, the term promoted arithmetic type refers to promoted
1641 integral types plus floating types. */
1645 }
1647 /* Create any builtin operator overload candidates for the operator in
1648 question given the converted operand types TYPE1 and TYPE2. The other
1649 args are passed through from add_builtin_candidates to
1650 build_builtin_candidate.
1652 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1653 If CODE is requires candidates operands of the same type of the kind
1654 of which TYPE1 and TYPE2 are, we add both candidates
1655 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1657 static void
1661 {
1663 {
1671 }
1674 {
1676 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1677 and VQ is either volatile or empty, there exist candidate operator
1678 functions of the form
1679 VQ T& operator++(VQ T&);
1680 T operator++(VQ T&, int);
1681 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1682 type other than bool, and VQ is either volatile or empty, there exist
1683 candidate operator functions of the form
1684 VQ T& operator--(VQ T&);
1685 T operator--(VQ T&, int);
1686 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1687 complete object type, and VQ is either volatile or empty, there exist
1688 candidate operator functions of the form
1689 T*VQ& operator++(T*VQ&);
1690 T*VQ& operator--(T*VQ&);
1691 T* operator++(T*VQ&, int);
1692 T* operator--(T*VQ&, int); */
1701 {
1704 }
1707 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1708 exist candidate operator functions of the form
1710 T& operator*(T*);
1712 8 For every function type T, there exist candidate operator functions of
1713 the form
1714 T& operator*(T*); */
1723 /* 9 For every type T, there exist candidate operator functions of the form
1724 T* operator+(T*);
1726 10For every promoted arithmetic type T, there exist candidate operator
1727 functions of the form
1728 T operator+(T);
1729 T operator-(T); */
1740 /* 11For every promoted integral type T, there exist candidate operator
1741 functions of the form
1742 T operator~(T); */
1749 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1750 is the same type as C2 or is a derived class of C2, T is a complete
1751 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1752 there exist candidate operator functions of the form
1753 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1754 where CV12 is the union of CV1 and CV2. */
1759 {
1769 }
1772 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1773 didate operator functions of the form
1774 LR operator*(L, R);
1775 LR operator/(L, R);
1776 LR operator+(L, R);
1777 LR operator-(L, R);
1778 bool operator<(L, R);
1779 bool operator>(L, R);
1780 bool operator<=(L, R);
1781 bool operator>=(L, R);
1782 bool operator==(L, R);
1783 bool operator!=(L, R);
1784 where LR is the result of the usual arithmetic conversions between
1785 types L and R.
1787 14For every pair of types T and I, where T is a cv-qualified or cv-
1788 unqualified complete object type and I is a promoted integral type,
1789 there exist candidate operator functions of the form
1790 T* operator+(T*, I);
1791 T& operator[](T*, I);
1792 T* operator-(T*, I);
1793 T* operator+(I, T*);
1794 T& operator[](I, T*);
1796 15For every T, where T is a pointer to complete object type, there exist
1797 candidate operator functions of the form112)
1798 ptrdiff_t operator-(T, T);
1800 16For every pointer or enumeration type T, there exist candidate operator
1801 functions of the form
1802 bool operator<(T, T);
1803 bool operator>(T, T);
1804 bool operator<=(T, T);
1805 bool operator>=(T, T);
1806 bool operator==(T, T);
1807 bool operator!=(T, T);
1809 17For every pointer to member type T, there exist candidate operator
1810 functions of the form
1811 bool operator==(T, T);
1812 bool operator!=(T, T); */
1818 {
1821 }
1835 {
1838 }
1841 {
1844 }
1845 /* FALLTHROUGH */
1859 {
1862 }
1864 {
1867 }
1875 {
1878 }
1880 {
1883 }
1886 /* 18For every pair of promoted integral types L and R, there exist candi-
1887 date operator functions of the form
1888 LR operator%(L, R);
1889 LR operator&(L, R);
1890 LR operator^(L, R);
1891 LR operator|(L, R);
1892 L operator<<(L, R);
1893 L operator>>(L, R);
1894 where LR is the result of the usual arithmetic conversions between
1895 types L and R. */
1907 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1908 type, VQ is either volatile or empty, and R is a promoted arithmetic
1909 type, there exist candidate operator functions of the form
1910 VQ L& operator=(VQ L&, R);
1911 VQ L& operator*=(VQ L&, R);
1912 VQ L& operator/=(VQ L&, R);
1913 VQ L& operator+=(VQ L&, R);
1914 VQ L& operator-=(VQ L&, R);
1916 20For every pair T, VQ), where T is any type and VQ is either volatile
1917 or empty, there exist candidate operator functions of the form
1918 T*VQ& operator=(T*VQ&, T*);
1920 21For every pair T, VQ), where T is a pointer to member type and VQ is
1921 either volatile or empty, there exist candidate operator functions of
1922 the form
1923 VQ T& operator=(VQ T&, T);
1925 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1926 unqualified complete object type, VQ is either volatile or empty, and
1927 I is a promoted integral type, there exist candidate operator func-
1928 tions of the form
1929 T*VQ& operator+=(T*VQ&, I);
1930 T*VQ& operator-=(T*VQ&, I);
1932 23For every triple L, VQ, R), where L is an integral or enumeration
1933 type, VQ is either volatile or empty, and R is a promoted integral
1934 type, there exist candidate operator functions of the form
1936 VQ L& operator%=(VQ L&, R);
1937 VQ L& operator<<=(VQ L&, R);
1938 VQ L& operator>>=(VQ L&, R);
1939 VQ L& operator&=(VQ L&, R);
1940 VQ L& operator^=(VQ L&, R);
1941 VQ L& operator|=(VQ L&, R); */
1945 {
1949 {
1952 }
1978 {
1981 }
1986 }
1991 /* [over.built]
1993 For every pair of promoted arithmetic types L and R, there
1994 exist candidate operator functions of the form
1996 LR operator?(bool, L, R);
1998 where LR is the result of the usual arithmetic conversions
1999 between types L and R.
2001 For every type T, where T is a pointer or pointer-to-member
2002 type, there exist candidate operator functions of the form T
2003 operator?(bool, T, T); */
2007 /* That's OK. */
2010 /* Otherwise, the types should be pointers. */
2019 /* We don't check that the two types are the same; the logic
2020 below will actually create two candidates; one in which both
2021 parameter types are TYPE1, and one in which both parameter
2022 types are TYPE2. */
2027 }
2029 /* If we're dealing with two pointer types or two enumeral types,
2030 we need candidates for both of them. */
2039 {
2040 build_builtin_candidate
2042 build_builtin_candidate
2045 }
2047 build_builtin_candidate
2049 }
2051 tree
2053 {
2059 }
2061 /* There are three conditions of builtin candidates:
2063 1) bool-taking candidates. These are the same regardless of the input.
2064 2) pointer-pair taking candidates. These are generated for each type
2065 one of the input types converts to.
2066 3) arithmetic candidates. According to the standard, we should generate
2067 all of these, but I'm trying not to...
2069 Here we generate a superset of the possible candidates for this particular
2070 case. That is a subset of the full set the standard defines, plus some
2071 other cases which the standard disallows. add_builtin_candidate will
2072 filter out the invalid set. */
2074 static void
2078 {
2082 /* TYPES[i] is the set of possible builtin-operator parameter types
2083 we will consider for the Ith argument. These are represented as
2084 a TREE_LIST; the TREE_VALUE of each node is the potential
2085 parameter type. */
2089 {
2092 else
2094 }
2097 {
2098 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2099 and VQ is either volatile or empty, there exist candidate operator
2100 functions of the form
2101 VQ T& operator++(VQ T&); */
2111 /* 24There also exist candidate operator functions of the form
2112 bool operator!(bool);
2113 bool operator&&(bool, bool);
2114 bool operator||(bool, bool); */
2117 build_builtin_candidate
2124 build_builtin_candidate
2142 /* FALLTHROUGH */
2146 }
2151 {
2153 ;
2155 {
2156 tree convs;
2164 {
2171 }
2177 {
2190 {
2196 }
2200 }
2201 }
2202 else
2203 {
2209 {
2215 }
2217 }
2218 }
2220 /* Run through the possible parameter types of both arguments,
2221 creating candidates with those parameter types. */
2223 {
2226 add_builtin_candidate
2229 else
2230 add_builtin_candidate
2233 }
2236 }
2239 /* If TMPL can be successfully instantiated as indicated by
2240 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2242 TMPL is the template. EXPLICIT_TARGS are any explicit template
2243 arguments. ARGLIST is the arguments provided at the call-site.
2244 The RETURN_TYPE is the desired type for conversion operators. If
2245 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2246 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2247 add_conv_candidate. */
2254 unification_kind_t strict)
2255 {
2261 tree fn;
2263 /* We don't do deduction on the in-charge parameter, the VTT
2264 parameter or 'this'. */
2274 args_without_in_chrg,
2284 /* In [class.copy]:
2286 A member function template is never instantiated to perform the
2287 copy of a class object to an object of its class type.
2289 It's a little unclear what this means; the standard explicitly
2290 does allow a template to be used to copy a class. For example,
2291 in:
2293 struct A {
2294 A(A&);
2295 template <class T> A(const T&);
2296 };
2297 const A f ();
2298 void g () { A a (f ()); }
2300 the member template will be used to make the copy. The section
2301 quoted above appears in the paragraph that forbids constructors
2302 whose only parameter is (a possibly cv-qualified variant of) the
2303 class type, and a logical interpretation is that the intent was
2304 to forbid the instantiation of member templates which would then
2305 have that form. */
2307 {
2310 ctype))
2312 }
2315 /* Aha, this is a conversion function. */
2318 else
2323 /* This situation can occur if a member template of a template
2324 class is specialized. Then, instantiate_template might return
2325 an instantiation of the specialization, in which case the
2326 DECL_TI_TEMPLATE field will point at the original
2327 specialization. For example:
2329 template <class T> struct S { template <class U> void f(U);
2330 template <> void f(int) {}; };
2331 S<double> sd;
2332 sd.f(3);
2334 Here, TMPL will be template <class U> S<double>::f(U).
2335 And, instantiate template will give us the specialization
2336 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2337 for this will point at template <class T> template <> S<T>::f(int),
2338 so that we can find the definition. For the purposes of
2339 overload resolution, however, we want the original TMPL. */
2341 else
2345 }
2352 unification_kind_t strict)
2353 {
2354 return
2359 }
2366 {
2367 return
2371 }
2373 /* The CANDS are the set of candidates that were considered for
2374 overload resolution. Return the set of viable candidates. If none
2375 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2376 is true if a candidate should be considered viable only if it is
2377 strictly viable. */
2383 {
2394 {
2397 {
2403 }
2404 else
2406 }
2409 }
2411 static bool
2413 {
2418 }
2420 static tree
2422 {
2423 /* Fix this to work on non-lvalues. */
2425 }
2427 /* Returns true iff functions are equivalent. Equivalent functions are
2428 not '==' only if one is a function-local extern function or if
2429 both are extern "C". */
2433 {
2438 }
2440 /* Print information about one overload candidate CANDIDATE. STR is the
2441 text to print before the candidate itself and ERRFN is the routine
2442 (i.e. error, warning or pedwarn) used to do the printing. */
2444 static void
2447 {
2449 {
2459 else
2462 }
2465 else
2468 }
2470 static void
2472 {
2477 /* There may be duplicates in the set of candidates. We put off
2478 checking this condition as long as possible, since we have no way
2479 to eliminate duplicates from a set of functions in less than n^2
2480 time. Now we are about to emit an error message, so it is more
2481 permissible to go slowly. */
2483 {
2485 /* Skip builtin candidates and conversion functions. */
2490 {
2494 else
2496 }
2497 }
2501 {
2504 }
2505 }
2507 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2508 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2509 the result of the conversion function to convert it to the final
2510 desired type. Merge the the two sequences into a single sequence,
2511 and return the merged sequence. */
2513 static tree
2515 {
2521 /* Find the end of the second conversion sequence. */
2526 /* Replace the identity conversion with the user conversion
2527 sequence. */
2530 /* The entire sequence is a user-conversion sequence. */
2534 }
2536 /* Returns the best overload candidate to perform the requested
2537 conversion. This function is used for three the overloading situations
2538 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2539 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2540 per [dcl.init.ref], so we ignore temporary bindings. */
2544 {
2551 /* We represent conversion within a hierarchy using RVALUE_CONV and
2552 BASE_CONV, as specified by [over.best.ics]; these become plain
2553 constructor calls, as specified in [dcl.init]. */
2559 complete_ctor_identifier,
2569 {
2570 tree t;
2577 /* We should never try to call the abstract or base constructor
2578 from here. */
2583 }
2585 {
2595 flags,
2596 DEDUCE_CALL);
2597 else
2601 flags);
2605 }
2611 {
2612 tree fns;
2616 /* If we are called to convert to a reference type, we are trying to
2617 find an lvalue binding, so don't even consider temporaries. If
2618 we don't find an lvalue binding, the caller will try again to
2619 look for a temporary binding. */
2624 {
2627 /* [over.match.funcs] For conversion functions, the function
2628 is considered to be a member of the class of the implicit
2629 object argument for the purpose of defining the type of
2630 the implicit object parameter.
2632 So we pass fromtype as CTYPE to add_*_candidate. */
2636 NULL_TREE,
2639 conversion_path,
2640 flags,
2641 DEDUCE_CONV);
2642 else
2644 args,
2646 conversion_path,
2647 flags);
2650 {
2661 }
2662 }
2663 }
2671 {
2673 {
2677 }
2684 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2685 ambiguous conversion is no worse than another user-defined
2686 conversion. */
2689 }
2691 /* Build the user conversion sequence. */
2692 convs = build_conv
2699 /* Combine it with the second conversion sequence. */
2707 }
2709 tree
2711 {
2716 {
2720 }
2722 }
2724 /* Find the possibly overloaded set of functions corresponding to a
2725 call of the form SCOPE::NAME (...). NAME might be a
2726 TEMPLATE_ID_EXPR, OVERLOAD, _DECL, IDENTIFIER_NODE or LOOKUP_EXPR. */
2728 tree
2730 {
2731 tree fn;
2736 {
2739 }
2747 else
2748 {
2751 {
2753 scope);
2755 }
2759 else
2762 fn = (adjust_result_of_qualified_name_lookup
2765 /* It might be the name of a function pointer member. */
2768 }
2771 {
2774 }
2776 {
2784 else
2786 }
2789 }
2791 /* Do any initial processing on the arguments to a function call. */
2793 static tree
2795 {
2796 tree t;
2798 {
2804 {
2807 }
2812 }
2814 }
2816 /* Perform overload resolution on FN, which is called with the ARGS.
2818 Return the candidate function selected by overload resolution, or
2819 NULL if the event that overload resolution failed. In the case
2820 that overload resolution fails, *CANDIDATES will be the set of
2821 candidates considered, and ANY_VIABLE_P will be set to true or
2822 false to indicate whether or not any of the candidates were
2823 viable.
2825 The ARGS should already have gone through RESOLVE_ARGS before this
2826 function is called. */
2830 tree args,
2833 {
2841 /* Check FN and ARGS. */
2851 {
2855 }
2857 /* Add the various candidate functions. */
2861 LOOKUP_NORMAL,
2862 candidates);
2870 }
2872 /* Return an expression for a call to FN (a namespace-scope function,
2873 or a static member function) with the ARGS. */
2875 tree
2877 {
2888 {
2896 else
2902 }
2905 }
2907 /* Build a call to a global operator new. FNNAME is the name of the
2908 operator (either "operator new" or "operator new[]") and ARGS are
2909 the arguments provided. *SIZE points to the total number of bytes
2910 required by the allocation, and is updated if that is changed here.
2911 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2912 function determins that no cookie should be used, after all,
2913 *COOKIE_SIZE is set to NULL_TREE. */
2915 tree
2917 {
2918 tree fns;
2930 /* Figure out what function is being called. */
2933 /* If no suitable function could be found, issue an error message
2934 and give up. */
2936 {
2940 else
2946 }
2948 /* If a cookie is required, add some extra space. Whether
2949 or not a cookie is required cannot be determined until
2950 after we know which function was called. */
2952 {
2955 {
2957 /* In G++ 3.2, the check was implemented incorrectly; it
2958 looked at the placement expression, rather than the
2959 type of the function. */
2962 ptr_type_node))
2964 }
2965 else
2966 {
2967 tree arg_types;
2970 /* Skip the size_t parameter. */
2972 /* Check the remaining parameters (if any). */
2976 ptr_type_node))
2978 }
2979 /* If we need a cookie, adjust the number of bytes allocated. */
2981 {
2982 /* Update the total size. */
2984 /* Update the argument list to reflect the adjusted size. */
2986 }
2987 else
2989 }
2991 /* Build the CALL_EXPR. */
2993 }
2995 static tree
2997 {
3004 {
3005 /* It's no good looking for an overloaded operator() on a
3006 pointer-to-member-function. */
3007 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3009 }
3021 {
3026 {
3034 else
3035 add_function_candidate
3038 }
3039 }
3044 {
3056 {
3059 add_template_conv_candidate
3063 else
3067 }
3068 }
3072 {
3076 }
3080 {
3084 }
3086 /* Since cand->fn will be a type, not a function, for a conversion
3087 function, we must be careful not to unconditionally look at
3088 DECL_NAME here. */
3093 obj = convert_like_with_context
3096 /* FIXME */
3098 }
3100 static void
3103 {
3108 else
3112 {
3129 else
3131 }
3132 }
3134 /* Return the implicit conversion sequence that could be used to
3135 convert E1 to E2 in [expr.cond]. */
3137 static tree
3139 {
3142 tree conv;
3144 /* [expr.cond]
3146 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3147 implicitly converted (clause _conv_) to the type "reference to
3148 T2", subject to the constraint that in the conversion the
3149 reference must bind directly (_dcl.init.ref_) to E1. */
3151 {
3153 t1,
3154 e1,
3155 LOOKUP_NO_TEMP_BIND);
3158 }
3160 /* [expr.cond]
3162 If E1 and E2 have class type, and the underlying class types are
3163 the same or one is a base class of the other: E1 can be converted
3164 to match E2 if the class of T2 is the same type as, or a base
3165 class of, the class of T1, and the cv-qualification of T2 is the
3166 same cv-qualification as, or a greater cv-qualification than, the
3167 cv-qualification of T1. If the conversion is applied, E1 is
3168 changed to an rvalue of type T2 that still refers to the original
3169 source class object (or the appropriate subobject thereof). */
3173 {
3175 {
3181 }
3182 else
3184 }
3186 /* [expr.cond]
3188 E1 can be converted to match E2 if E1 can be implicitly converted
3189 to the type that expression E2 would have if E2 were converted to
3190 an rvalue (or the type it has, if E2 is an rvalue). */
3192 }
3194 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3195 arguments to the conditional expression. */
3197 tree
3199 {
3200 tree arg2_type;
3201 tree arg3_type;
3202 tree result;
3208 /* As a G++ extension, the second argument to the conditional can be
3209 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3210 c'.) If the second operand is omitted, make sure it is
3211 calculated only once. */
3213 {
3217 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3220 else
3222 }
3224 /* [expr.cond]
3226 The first expr ession is implicitly converted to bool (clause
3227 _conv_). */
3230 /* If something has already gone wrong, just pass that fact up the
3231 tree. */
3240 /* [expr.cond]
3242 If either the second or the third operand has type (possibly
3243 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3244 array-to-pointer (_conv.array_), and function-to-pointer
3245 (_conv.func_) standard conversions are performed on the second
3246 and third operands. */
3250 {
3251 /* Do the conversions. We don't these for `void' type arguments
3252 since it can't have any effect and since decay_conversion
3253 does not handle that case gracefully. */
3261 /* [expr.cond]
3263 One of the following shall hold:
3265 --The second or the third operand (but not both) is a
3266 throw-expression (_except.throw_); the result is of the
3267 type of the other and is an rvalue.
3269 --Both the second and the third operands have type void; the
3270 result is of type void and is an rvalue. */
3277 else
3278 {
3282 }
3286 }
3287 /* [expr.cond]
3289 Otherwise, if the second and third operand have different types,
3290 and either has (possibly cv-qualified) class type, an attempt is
3291 made to convert each of those operands to the type of the other. */
3294 {
3298 /* [expr.cond]
3300 If both can be converted, or one can be converted but the
3301 conversion is ambiguous, the program is ill-formed. If
3302 neither can be converted, the operands are left unchanged and
3303 further checking is performed as described below. If exactly
3304 one conversion is possible, that conversion is applied to the
3305 chosen operand and the converted operand is used in place of
3306 the original operand for the remainder of this section. */
3311 {
3314 }
3316 {
3319 /* That may not quite have done the trick. If the two types
3320 are cv-qualified variants of one another, we will have
3321 just used an IDENTITY_CONV. */
3325 }
3327 {
3333 }
3334 }
3336 /* [expr.cond]
3338 If the second and third operands are lvalues and have the same
3339 type, the result is of that type and is an lvalue. */
3342 {
3345 }
3347 /* [expr.cond]
3349 Otherwise, the result is an rvalue. If the second and third
3350 operand do not have the same type, and either has (possibly
3351 cv-qualified) class type, overload resolution is used to
3352 determine the conversions (if any) to be applied to the operands
3353 (_over.match.oper_, _over.built_). */
3357 {
3359 tree conv;
3362 /* Rearrange the arguments so that add_builtin_candidate only has
3363 to know about two args. In build_builtin_candidates, the
3364 arguments are unscrambled. */
3369 COND_EXPR,
3370 NOP_EXPR,
3372 args,
3373 LOOKUP_NORMAL);
3375 /* [expr.cond]
3377 If the overload resolution fails, the program is
3378 ill-formed. */
3381 {
3385 }
3388 {
3392 }
3394 /* [expr.cond]
3396 Otherwise, the conversions thus determined are applied, and
3397 the converted operands are used in place of the original
3398 operands for the remainder of this section. */
3405 }
3407 /* [expr.cond]
3409 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3410 and function-to-pointer (_conv.func_) standard conversions are
3411 performed on the second and third operands.
3413 We need to force the lvalue-to-rvalue conversion here for class types,
3414 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3415 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3416 regions.
3418 We use ocp_convert rather than build_user_type_conversion because the
3419 latter returns NULL_TREE on failure, while the former gives an error. */
3430 /* [expr.cond]
3432 After those conversions, one of the following shall hold:
3434 --The second and third operands have the same type; the result is of
3435 that type. */
3438 /* [expr.cond]
3440 --The second and third operands have arithmetic or enumeration
3441 type; the usual arithmetic conversions are performed to bring
3442 them to a common type, and the result is of that type. */
3447 {
3448 /* In this case, there is always a common type. */
3450 arg3_type);
3465 }
3466 /* [expr.cond]
3468 --The second and third operands have pointer type, or one has
3469 pointer type and the other is a null pointer constant; pointer
3470 conversions (_conv.ptr_) and qualification conversions
3471 (_conv.qual_) are performed to bring them to their composite
3472 pointer type (_expr.rel_). The result is of the composite
3473 pointer type.
3475 --The second and third operands have pointer to member type, or
3476 one has pointer to member type and the other is a null pointer
3477 constant; pointer to member conversions (_conv.mem_) and
3478 qualification conversions (_conv.qual_) are performed to bring
3479 them to a common type, whose cv-qualification shall match the
3480 cv-qualification of either the second or the third operand.
3481 The result is of the common type. */
3492 {
3497 }
3500 {
3503 }
3505 valid_operands:
3507 /* Expand both sides into the same slot, hopefully the target of the
3508 ?: expression. We used to check for TARGET_EXPRs here, but now we
3509 sometimes wrap them in NOP_EXPRs so the test would fail. */
3513 /* If this expression is an rvalue, but might be mistaken for an
3514 lvalue, we must add a NON_LVALUE_EXPR. */
3519 }
3521 /* OPERAND is an operand to an expression. Perform necessary steps
3522 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3523 returned. */
3525 static tree
3527 {
3529 {
3535 /* Make sure the template type is instantiated now. */
3537 }
3540 }
3542 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3543 OVERLOAD) to the CANDIDATES, returning an updated list of
3544 CANDIDATES. The ARGS are the arguments provided to the call,
3545 without any implicit object parameter. The EXPLICIT_TARGS are
3546 explicit template arguments provided. TEMPLATE_ONLY is true if
3547 only template fucntions should be considered. CONVERSION_PATH,
3548 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3550 static void
3556 {
3557 tree ctype;
3558 tree non_static_args;
3561 /* Delay creating the implicit this parameter until it is needed. */
3565 {
3566 tree fn;
3567 tree fn_args;
3570 /* Figure out which set of arguments to use. */
3572 {
3573 /* If this function is a non-static member, prepend the implicit
3574 object parameter. */
3580 }
3581 else
3582 /* Otherwise, just use the list of arguments provided. */
3587 fn,
3588 ctype,
3589 explicit_targs,
3590 fn_args,
3591 NULL_TREE,
3592 access_path,
3593 conversion_path,
3594 flags,
3595 DEDUCE_CALL);
3598 fn,
3599 ctype,
3600 fn_args,
3601 access_path,
3602 conversion_path,
3603 flags);
3605 }
3606 }
3608 tree
3610 {
3615 tree conv;
3625 {
3629 }
3630 else
3636 {
3641 /* Use build_op_new_call and build_op_delete_call instead. */
3649 }
3655 {
3662 }
3677 /* Add namespace-scope operators to the list of functions to
3678 consider. */
3682 /* Add class-member operators to the candidate set. */
3684 {
3685 tree fns;
3696 }
3698 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3699 to know about two args; a builtin candidate will always have a first
3700 parameter of type bool. We'll handle that in
3701 build_builtin_candidate. */
3703 {
3707 }
3708 else
3709 {
3713 }
3718 {
3721 /* For these, the built-in candidates set is empty
3722 [over.match.oper]/3. We don't want non-strict matches
3723 because exact matches are always possible with built-in
3724 operators. The built-in candidate set for COMPONENT_REF
3725 would be empty too, but since there are no such built-in
3726 operators, we accept non-strict matches for them. */
3733 }
3737 {
3739 {
3742 /* Look for an `operator++ (int)'. If they didn't have
3743 one, then we fall back to the old way of doing things. */
3746 fnname,
3750 else
3754 /* The caller will deal with these. */
3762 }
3764 {
3767 }
3769 }
3773 {
3775 {
3778 }
3780 }
3783 {
3789 {
3793 cand == candidates
3796 }
3799 }
3801 /* Check for comparison of different enum types. */
3803 {
3814 {
3817 }
3821 }
3823 /* We need to strip any leading REF_BIND so that bitfields don't cause
3824 errors. This should not remove any important conversions, because
3825 builtins don't apply to class objects directly. */
3831 {
3836 }
3838 {
3843 }
3845 builtin:
3847 {
3895 return build_m_component_ref
3898 /* The caller will deal with these. */
3907 }
3908 }
3910 /* Build a call to operator delete. This has to be handled very specially,
3911 because the restrictions on what signatures match are different from all
3912 other call instances. For a normal delete, only a delete taking (void *)
3913 or (void *, size_t) is accepted. For a placement delete, only an exact
3914 match with the placement new is accepted.
3916 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3917 ADDR is the pointer to be deleted.
3918 SIZE is the size of the memory block to be deleted.
3919 FLAGS are the usual overloading flags.
3920 PLACEMENT is the corresponding placement new call, or NULL_TREE. */
3922 tree
3925 {
3940 /* In [class.free]
3942 If the result of the lookup is ambiguous or inaccessible, or if
3943 the lookup selects a placement deallocation function, the
3944 program is ill-formed.
3946 Therefore, we ask lookup_fnfields to complain ambout ambiguity. */
3947 {
3951 }
3952 else
3959 {
3960 tree alloc_fn;
3961 tree call_expr;
3963 /* Find the allocation function that is being called. */
3965 /* Sometimes we have a COMPOUND_EXPR, rather than a simple
3966 CALL_EXPR. */
3969 /* Extract the function. */
3972 /* Then the second parm type. */
3974 /* Also the second argument. */
3976 }
3977 else
3978 {
3979 /* First try it without the size argument. */
3982 }
3984 /* Strip const and volatile from addr. */
3987 /* We make two tries at finding a matching `operator delete'. On
3988 the first pass, we look for an one-operator (or placement)
3989 operator delete. If we're not doing placement delete, then on
3990 the second pass we look for a two-argument delete. */
3992 {
3995 else
3996 /* Normal delete; now try to find a match including the size
3997 argument. */
4000 void_list_node));
4003 /* Go through the `operator delete' functions looking for one
4004 with a matching type. */
4006 fn;
4008 {
4009 tree t;
4011 /* Exception specifications on the `delete' operator do not
4012 matter. */
4014 NULL_TREE);
4015 /* We also don't compare attributes. We're really just
4016 trying to check the types of the first two parameters. */
4019 }
4021 /* If we found a match, we're done. */
4024 }
4026 /* If we have a matching function, call it. */
4028 {
4029 /* Make sure we have the actual function, and not an
4030 OVERLOAD. */
4033 /* If the FN is a member function, make sure that it is
4034 accessible. */
4040 else
4045 }
4047 /* If we are doing placement delete we do nothing if we don't find a
4048 matching op delete. */
4054 }
4056 /* If the current scope isn't allowed to access DECL along
4057 BASETYPE_PATH, give an error. The most derived class in
4058 BASETYPE_PATH is the one used to qualify DECL. */
4060 bool
4062 {
4064 {
4069 else
4073 }
4076 }
4078 /* Perform the conversions in CONVS on the expression EXPR.
4079 FN and ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4080 indicates the `this' argument of a method. INNER is nonzero when
4081 being called to continue a conversion chain. It is negative when a
4082 reference binding will be applied, positive otherwise. */
4084 static tree
4086 {
4095 {
4098 {
4100 {
4103 }
4108 }
4113 }
4116 expr = dubious_conversion_warnings
4119 {
4121 {
4124 tree args;
4127 {
4134 /* We should never try to call the abstract or base constructor
4135 from here. */
4138 }
4139 else
4143 /* If this is a constructor or a function returning an aggr type,
4144 we need to build up a TARGET_EXPR. */
4148 /* The result of the call is then used to direct-initialize the object
4149 that is the destination of the copy-initialization. [dcl.init]
4151 Note that this step is not reflected in the conversion sequence;
4152 it affects the semantics when we actually perform the
4153 conversion, but is not considered during overload resolution.
4155 If the target is a class, that means call a ctor. */
4158 {
4160 expr = build_special_member_call
4163 /* Core issue 84, now a DR, says that we don't allow UDCs
4164 for these args (which deliberately breaks copy-init of an
4165 auto_ptr<Base> from an auto_ptr<Derived>). */
4168 /* Tell the user where this failing constructor call came from. */
4170 {
4172 warning
4176 error
4179 }
4180 else
4181 {
4184 convfn);
4187 convfn);
4188 }
4190 }
4192 }
4196 /* Convert a non-array constant variable to its underlying value, unless we
4197 are about to bind it to a reference, in which case we need to
4198 leave it as an lvalue. */
4204 /* Call build_user_type_conversion again for the error. */
4205 return build_user_type_conversion
4210 };
4218 {
4222 /* else fall through */
4225 {
4226 /* We are going to bind a reference directly to a base-class
4227 subobject of EXPR. */
4230 /* Build an expression for `*((base*) &expr)'. */
4235 }
4237 /* Copy-initialization where the cv-unqualified version of the source
4238 type is the same class as, or a derived class of, the class of the
4239 destination [is treated as direct-initialization]. [dcl.init] */
4246 {
4251 }
4255 {
4258 /* If necessary, create a temporary. */
4260 {
4263 }
4265 /* Take the address of the thing to which we will bind the
4266 reference. */
4271 /* Convert it to a pointer to the type referred to by the
4272 reference. This will adjust the pointer if a derived to
4273 base conversion is being performed. */
4275 expr);
4276 /* Convert the pointer to the desired reference type. */
4278 }
4284 /* Warn about deprecated conversion if appropriate. */
4290 }
4293 }
4295 /* Build a call to __builtin_trap which can be used in an expression. */
4297 static tree
4299 {
4303 else
4309 }
4311 /* ARG is being passed to a varargs function. Perform any conversions
4312 required. Array/function to pointer decay must have already happened.
4313 Return the converted value. */
4315 tree
4317 {
4321 /* Convert `float' to `double'. */
4323 else
4324 /* Convert `short' and `char' to full-size `int'. */
4330 {
4331 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4332 here and do a bitwise copy, but now cp_expr_size will abort if we
4333 try to do that. */
4338 }
4341 }
4343 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4345 tree
4347 {
4357 {
4358 /* Undefined behavior [expr.call] 5.2.2/7. */
4360 type);
4361 }
4364 }
4366 /* TYPE has been given to va_arg. Apply the default conversions which
4367 would have happened when passed via ellipsis. Return the promoted
4368 type, or the passed type if there is no change. */
4370 tree
4372 {
4373 tree promote;
4386 }
4388 /* ARG is a default argument expression being passed to a parameter of
4389 the indicated TYPE, which is a parameter to FN. Do any required
4390 conversions. Return the converted value. */
4392 tree
4394 {
4395 /* If the ARG is an unparsed default argument expression, the
4396 conversion cannot be performed. */
4398 {
4403 }
4411 {
4415 }
4416 else
4417 {
4418 /* This could get clobbered by the following call. */
4425 }
4428 }
4430 /* Returns the type which will really be used for passing an argument of
4431 type TYPE. */
4433 tree
4435 {
4436 /* Pass classes with copy ctors by invisible reference. */
4445 }
4447 /* Actually perform the appropriate conversion. */
4449 tree
4451 {
4453 ;
4454 /* Pass classes with copy ctors by invisible reference. */
4462 }
4464 /* Subroutine of the various build_*_call functions. Overload resolution
4465 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4466 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4467 bitmask of various LOOKUP_* flags which apply to the call itself. */
4469 static tree
4471 {
4481 /* Give any warnings we noticed during overload resolution. */
4493 /* The implicit parameters to a constructor are not considered by overload
4494 resolution, and must be of the proper type. */
4496 {
4501 /* We should never try to call the abstract constructor. */
4504 {
4505 converted_args = tree_cons
4509 }
4510 }
4511 /* Bypass access control for 'this' parameter. */
4513 {
4516 tree converted_arg;
4517 tree base_binfo;
4523 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4524 X is called for an object that is not of type X, or of a type
4525 derived from X, the behavior is undefined.
4527 So we can assume that anything passed as 'this' is non-null, and
4528 optimize accordingly. */
4530 /* Convert to the base in which the function was declared. */
4536 /* If fn was found by a using declaration, the conversion path
4537 will be to the derived class, not the base declaring fn. We
4538 must convert from derived to base. */
4550 }
4554 {
4558 val = convert_like_with_context
4563 }
4565 /* Default arguments */
4567 converted_args
4572 converted_args);
4574 /* Ellipsis */
4576 converted_args
4579 converted_args);
4585 converted_args);
4587 /* Avoid actually calling copy constructors and copy assignment operators,
4588 if possible. */
4594 {
4595 tree targ;
4599 /* Pull out the real argument, disregarding const-correctness. */
4606 {
4611 }
4612 else
4617 else
4620 /* [class.copy]: the copy constructor is implicitly defined even if
4621 the implementation elided its use. */
4625 /* If we're creating a temp and we already have one, don't create a
4626 new one. If we're not creating a temp but we get one, use
4627 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4628 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4629 temp or an INIT_EXPR otherwise. */
4631 {
4636 }
4639 {
4640 tree address;
4641 tree to = stabilize_reference
4646 /* Avoid a warning about this expression, if the address is
4647 never used. */
4650 }
4651 }
4655 {
4656 tree to = stabilize_reference
4662 }
4667 {
4680 else
4683 }
4686 else
4689 /* Recognize certain built-in functions so we can make tree-codes
4690 other than CALL_EXPR. We do this when it enables fold-const.c
4691 to do something useful. */
4696 {
4697 tree exp;
4701 }
4703 /* Some built-in function calls will be evaluated at
4704 compile-time in fold (). */
4714 }
4718 /* Make an expression which yields the address of the Java interface
4719 method FN. This is achieved by generating a call to libjava's
4720 _Jv_LookupInterfaceMethodIdx(). */
4722 static tree
4724 {
4730 {
4735 endlink)));
4736 java_iface_lookup_fn
4740 }
4742 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
4743 This is the first entry in the vtable. */
4745 integer_zero_node);
4747 /* Get the java.lang.Class pointer for the interface being called. */
4752 {
4754 iface);
4756 }
4759 /* Determine the itable index of FN. */
4762 {
4767 i++;
4768 }
4776 java_iface_lookup_fn);
4778 }
4780 /* Returns the value to use for the in-charge parameter when making a
4781 call to a function with the indicated NAME. */
4783 tree
4785 {
4796 /* This function should only be called with one of the names listed
4797 above. */
4800 }
4802 /* Build a call to a constructor, destructor, or an assignment
4803 operator for INSTANCE, an expression with class type. NAME
4804 indicates the special member function to call; ARGS are the
4805 arguments. BINFO indicates the base of INSTANCE that is to be
4806 passed as the `this' parameter to the member function called.
4808 FLAGS are the LOOKUP_* flags to use when processing the call.
4810 If NAME indicates a complete object constructor, INSTANCE may be
4811 NULL_TREE. In this case, the caller will call build_cplus_new to
4812 store the newly constructed object into a VAR_DECL. */
4814 tree
4817 {
4818 tree fns;
4819 /* The type of the subobject to be constructed or destroyed. */
4820 tree class_type;
4833 /* Handle the special case where INSTANCE is NULL_TREE. */
4835 {
4839 }
4847 /* Resolve the name. */
4853 /* When making a call to a constructor or destructor for a subobject
4854 that uses virtual base classes, pass down a pointer to a VTT for
4855 the subobject. */
4859 {
4860 tree vtt;
4861 tree sub_vtt;
4863 /* If the current function is a complete object constructor
4864 or destructor, then we fetch the VTT directly.
4865 Otherwise, we look it up using the VTT we were given. */
4871 current_vtt_parm,
4872 vtt);
4878 }
4881 }
4883 /* Return the NAME, as a C string. The NAME indicates a function that
4884 is a member of TYPE. *FREE_P is set to true if the caller must
4885 free the memory returned.
4887 Rather than go through all of this, we should simply set the names
4888 of constructors and destructors appropriately, and dispense with
4889 ctor_identifier, dtor_identifier, etc. */
4893 {
4896 /* Assume that we will not allocate memory. */
4898 /* Constructors and destructors are special. */
4900 {
4901 pretty_name
4903 /* For a destructor, add the '~'. */
4907 {
4909 /* Remember that we need to free the memory allocated. */
4911 }
4912 }
4913 else
4917 }
4919 /* Build a call to "INSTANCE.FN (ARGS)". */
4921 tree
4924 {
4928 tree access_binfo;
4929 tree optype;
4931 tree name;
4932 tree user_args;
4933 tree call;
4934 tree fn;
4935 tree class_type;
4946 /* Process the argument list. */
4960 {
4966 }
4975 {
4979 }
4986 /* XXX this should be handled before we get here. */
4988 {
4994 }
5000 {
5001 /* Callers should explicitly indicate whether they want to construct
5002 the complete object or just the part without virtual bases. */
5004 /* Similarly for destructors. */
5006 }
5008 /* It's OK to call destructors on cv-qualified objects. Therefore,
5009 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5011 {
5015 }
5021 {
5023 tree this_arglist;
5025 /* We can end up here for copy-init of same or base class. */
5032 else
5036 /* A member template. */
5038 class_type,
5039 explicit_targs,
5041 access_binfo,
5042 conversion_path,
5043 flags,
5044 DEDUCE_CALL);
5047 class_type,
5048 this_arglist,
5049 access_binfo,
5050 conversion_path,
5051 flags);
5052 }
5056 {
5057 /* XXX will LOOKUP_SPECULATIVELY be needed when this is done? */
5062 else
5063 {
5073 }
5076 }
5080 {
5086 user_args);
5091 }
5100 "abstract virtual `%#D' called from constructor"
5105 {
5108 }
5116 else
5117 {
5119 /* In an expression of the form `a->f()' where `f' turns out to
5120 be a static member function, `a' is none-the-less evaluated. */
5123 }
5126 }
5128 /* Returns true iff standard conversion sequence ICS1 is a proper
5129 subsequence of ICS2. */
5131 static bool
5133 {
5134 /* We can assume that a conversion of the same code
5135 between the same types indicates a subsequence since we only get
5136 here if the types we are converting from are the same. */
5143 {
5151 /* At this point, ICS1 cannot be a proper subsequence of
5152 ICS2. We can get a USER_CONV when we are comparing the
5153 second standard conversion sequence of two user conversion
5154 sequences. */
5164 }
5165 }
5167 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5168 be any _TYPE nodes. */
5170 bool
5172 {
5177 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5178 considers every class derived from itself. */
5181 }
5183 /* We build the ICS for an implicit object parameter as a pointer
5184 conversion sequence. However, such a sequence should be compared
5185 as if it were a reference conversion sequence. If ICS is the
5186 implicit conversion sequence for an implicit object parameter,
5187 modify it accordingly. */
5189 static void
5191 {
5193 {
5194 /* [over.match.funcs]
5196 For non-static member functions, the type of the
5197 implicit object parameter is "reference to cv X"
5198 where X is the class of which the function is a
5199 member and cv is the cv-qualification on the member
5200 function declaration. */
5202 tree reference_type;
5204 /* The `this' parameter is a pointer to a class type. Make the
5205 implict conversion talk about a reference to that same class
5206 type. */
5217 }
5218 }
5220 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5221 and return the type to which the reference refers. Otherwise,
5222 leave *ICS unchanged and return NULL_TREE. */
5224 static tree
5226 {
5228 {
5235 }
5238 }
5240 /* Compare two implicit conversion sequences according to the rules set out in
5241 [over.ics.rank]. Return values:
5243 1: ics1 is better than ics2
5244 -1: ics2 is better than ics1
5245 0: ics1 and ics2 are indistinguishable */
5247 static int
5249 {
5250 tree from_type1;
5251 tree from_type2;
5252 tree to_type1;
5253 tree to_type2;
5260 /* REF_BINDING is nonzero if the result of the conversion sequence
5261 is a reference type. In that case TARGET_TYPE is the
5262 type referred to by the reference. */
5263 tree target_type1;
5264 tree target_type2;
5266 /* Handle implicit object parameters. */
5270 /* Handle reference parameters. */
5274 /* [over.ics.rank]
5276 When comparing the basic forms of implicit conversion sequences (as
5277 defined in _over.best.ics_)
5279 --a standard conversion sequence (_over.ics.scs_) is a better
5280 conversion sequence than a user-defined conversion sequence
5281 or an ellipsis conversion sequence, and
5283 --a user-defined conversion sequence (_over.ics.user_) is a
5284 better conversion sequence than an ellipsis conversion sequence
5285 (_over.ics.ellipsis_). */
5295 {
5296 /* XXX Isn't this an extension? */
5297 /* Both ICS are bad. We try to make a decision based on what
5298 would have happenned if they'd been good. */
5306 /* We couldn't make up our minds; try to figure it out below. */
5307 }
5310 /* Both conversions are ellipsis conversions. */
5313 /* User-defined conversion sequence U1 is a better conversion sequence
5314 than another user-defined conversion sequence U2 if they contain the
5315 same user-defined conversion operator or constructor and if the sec-
5316 ond standard conversion sequence of U1 is better than the second
5317 standard conversion sequence of U2. */
5320 {
5333 /* We can just fall through here, after setting up
5334 FROM_TYPE1 and FROM_TYPE2. */
5337 }
5338 else
5339 {
5340 /* We're dealing with two standard conversion sequences.
5342 [over.ics.rank]
5344 Standard conversion sequence S1 is a better conversion
5345 sequence than standard conversion sequence S2 if
5347 --S1 is a proper subsequence of S2 (comparing the conversion
5348 sequences in the canonical form defined by _over.ics.scs_,
5349 excluding any Lvalue Transformation; the identity
5350 conversion sequence is considered to be a subsequence of
5351 any non-identity conversion sequence */
5362 }
5365 {
5370 }
5371 /* Otherwise, one sequence cannot be a subsequence of the other; they
5372 don't start with the same type. This can happen when comparing the
5373 second standard conversion sequence in two user-defined conversion
5374 sequences. */
5376 /* [over.ics.rank]
5378 Or, if not that,
5380 --the rank of S1 is better than the rank of S2 (by the rules
5381 defined below):
5383 Standard conversion sequences are ordered by their ranks: an Exact
5384 Match is a better conversion than a Promotion, which is a better
5385 conversion than a Conversion.
5387 Two conversion sequences with the same rank are indistinguishable
5388 unless one of the following rules applies:
5390 --A conversion that is not a conversion of a pointer, or pointer
5391 to member, to bool is better than another conversion that is such
5392 a conversion.
5394 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5395 so that we do not have to check it explicitly. */
5408 {
5413 }
5414 /* The rules for pointers to members A::* are just like the rules
5415 for pointers A*, except opposite: if B is derived from A then
5416 A::* converts to B::*, not vice versa. For that reason, we
5417 switch the from_ and to_ variables here. */
5422 {
5427 }
5432 {
5437 }
5442 {
5443 /* This was one of the pointer or pointer-like conversions.
5445 [over.ics.rank]
5447 --If class B is derived directly or indirectly from class A,
5448 conversion of B* to A* is better than conversion of B* to
5449 void*, and conversion of A* to void* is better than
5450 conversion of B* to void*. */
5453 {
5455 deref_from_type2))
5458 deref_from_type1))
5460 }
5463 {
5465 {
5467 {
5469 deref_to_type1))
5471 }
5472 /* We know that DEREF_TO_TYPE1 is `void' here. */
5474 deref_to_type2))
5476 }
5477 }
5480 {
5481 /* [over.ics.rank]
5483 --If class B is derived directly or indirectly from class A
5484 and class C is derived directly or indirectly from B,
5486 --conversion of C* to B* is better than conversion of C* to
5487 A*,
5489 --conversion of B* to A* is better than conversion of C* to
5490 A* */
5492 {
5494 deref_to_type2))
5497 deref_to_type1))
5499 }
5501 {
5503 deref_from_type1))
5506 deref_from_type2))
5508 }
5509 }
5510 }
5513 {
5516 /* [over.ics.rank]
5518 --binding of an expression of type C to a reference of type
5519 B& is better than binding an expression of type C to a
5520 reference of type A&
5522 --conversion of C to B is better than conversion of C to A, */
5525 {
5530 }
5531 }
5534 {
5537 /* [over.ics.rank]
5539 --binding of an expression of type B to a reference of type
5540 A& is better than binding an expression of type C to a
5541 reference of type A&,
5543 --onversion of B to A is better than conversion of C to A */
5546 {
5551 }
5552 }
5554 /* [over.ics.rank]
5556 --S1 and S2 differ only in their qualification conversion and yield
5557 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5558 qualification signature of type T1 is a proper subset of the cv-
5559 qualification signature of type T2 */
5565 /* [over.ics.rank]
5567 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5568 types to which the references refer are the same type except for
5569 top-level cv-qualifiers, and the type to which the reference
5570 initialized by S2 refers is more cv-qualified than the type to
5571 which the reference initialized by S1 refers */
5577 /* Neither conversion sequence is better than the other. */
5579 }
5581 /* The source type for this standard conversion sequence. */
5583 static tree
5585 {
5587 {
5592 }
5594 }
5596 /* Note a warning about preferring WINNER to LOSER. We do this by storing
5597 a pointer to LOSER and re-running joust to produce the warning if WINNER
5598 is actually used. */
5600 static void
5602 {
5606 }
5608 /* Compare two candidates for overloading as described in
5609 [over.match.best]. Return values:
5611 1: cand1 is better than cand2
5612 -1: cand2 is better than cand1
5613 0: cand1 and cand2 are indistinguishable */
5615 static int
5617 {
5621 /* Candidates that involve bad conversions are always worse than those
5622 that don't. */
5628 /* If we have two pseudo-candidates for conversions to the same type,
5629 or two candidates for the same function, arbitrarily pick one. */
5634 /* a viable function F1
5635 is defined to be a better function than another viable function F2 if
5636 for all arguments i, ICSi(F1) is not a worse conversion sequence than
5637 ICSi(F2), and then */
5639 /* for some argument j, ICSj(F1) is a better conversion sequence than
5640 ICSj(F2) */
5642 /* For comparing static and non-static member functions, we ignore
5643 the implicit object parameter of the non-static function. The
5644 standard says to pretend that the static function has an object
5645 parm, but that won't work with operator overloading. */
5648 {
5654 {
5657 }
5658 else
5660 }
5663 {
5669 {
5681 {
5688 else
5693 {
5697 }
5698 else
5700 }
5703 {
5706 }
5708 }
5709 }
5711 /* warn about confusing overload resolution for user-defined conversions,
5712 either between a constructor and a conversion op, or between two
5713 conversion ops. */
5717 /* Don't warn if the two conv ops convert to the same type... */
5721 {
5724 {
5726 tree convn;
5729 else
5738 /* Don't complain about `operator char *()' beating
5741 {
5749 }
5750 else
5752 }
5753 }
5758 /* or, if not that,
5759 F1 is a non-template function and F2 is a template function
5760 specialization. */
5767 /* or, if not that,
5768 F1 and F2 are template functions and the function template for F1 is
5769 more specialized than the template for F2 according to the partial
5770 ordering rules. */
5773 {
5774 winner = more_specialized
5776 DEDUCE_ORDER,
5777 /* Tell the deduction code how many real function arguments
5778 we saw, not counting the implicit 'this' argument. But,
5779 add_function_candidate() suppresses the "this" argument
5780 for constructors.
5782 [temp.func.order]: The presence of unused ellipsis and default
5783 arguments has no effect on the partial ordering of function
5784 templates. */
5790 }
5792 /* or, if not that,
5793 the context is an initialization by user-defined conversion (see
5794 _dcl.init_ and _over.match.user_) and the standard conversion
5795 sequence from the return type of F1 to the destination type (i.e.,
5796 the type of the entity being initialized) is a better conversion
5797 sequence than the standard conversion sequence from the return type
5798 of F2 to the destination type. */
5801 {
5805 }
5807 /* Check whether we can discard a builtin candidate, either because we
5808 have two identical ones or matching builtin and non-builtin candidates.
5810 (Pedantically in the latter case the builtin which matched the user
5811 function should not be added to the overload set, but we spot it here.
5813 [over.match.oper]
5814 ... the builtin candidates include ...
5815 - do not have the same parameter type list as any non-template
5816 non-member candidate. */
5820 {
5826 {
5828 /* Two built-in candidates; arbitrarily pick one. */
5831 /* cand1 is built-in; prefer cand2. */
5833 else
5834 /* cand2 is built-in; prefer cand1. */
5836 }
5837 }
5839 /* If the two functions are the same (this can happen with declarations
5840 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
5845 tweak:
5847 /* Extension: If the worst conversion for one candidate is worse than the
5848 worst conversion for the other, take the first. */
5850 {
5855 {
5860 }
5866 {
5868 {
5870 /* Translators note: This message is a continuation of the
5871 previous one, aligned on the right. */
5875 }
5876 else
5879 }
5880 }
5884 }
5886 /* Given a list of candidates for overloading, find the best one, if any.
5887 This algorithm has a worst case of O(2n) (winner is last), and a best
5888 case of O(n/2) (totally ambiguous); much better than a sorting
5889 algorithm. */
5893 {
5898 /* Walk through the list once, comparing each current champ to the next
5899 candidate, knocking out a candidate or two with each comparison. */
5902 {
5906 else
5907 {
5909 {
5914 }
5915 else
5916 {
5919 }
5922 }
5923 }
5925 /* Make sure the champ is better than all the candidates it hasn't yet
5926 been compared to. */
5929 challenger != champ
5932 {
5936 }
5939 }
5941 /* Returns nonzero if things of type FROM can be converted to TO. */
5943 bool
5945 {
5947 }
5949 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
5951 bool
5953 {
5956 }
5958 /* Like can_convert_arg, but allows dubious conversions as well. */
5960 bool
5962 {
5964 }
5966 /* Convert EXPR to TYPE. Return the converted expression.
5968 Note that we allow bad conversions here because by the time we get to
5969 this point we are committed to doing the conversion. If we end up
5970 doing a bad conversion, convert_like will complain. */
5972 tree
5974 {
5975 tree conv;
5980 LOOKUP_NORMAL);
5982 {
5985 }
5988 }
5990 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
5991 is being bound to a temporary. Create and return a new VAR_DECL
5992 with the indicated TYPE; this variable will store the value to
5993 which the reference is bound. */
5995 tree
5997 {
5998 tree var;
6000 /* Create the variable. */
6005 /* Register the variable. */
6007 {
6008 /* Namespace-scope or local static; give it a mangled name. */
6009 tree name;
6016 }
6017 else
6018 {
6019 /* Create a new cleanup level if necessary. */
6021 /* Don't push unnamed temps. Do set DECL_CONTEXT, though. */
6023 }
6026 }
6028 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6029 initializing a variable of that TYPE. If DECL is non-NULL, it is
6030 the VAR_DECL being initialized with the EXPR. (In that case, the
6031 type of DECL will be TYPE.)
6033 Return the converted expression. */
6035 tree
6037 {
6038 tree conv;
6045 {
6048 }
6050 /* If DECL is non-NULL, then this special rule applies:
6052 [class.temporary]
6054 The temporary to which the reference is bound or the temporary
6055 that is the complete object to which the reference is bound
6056 persists for the lifetime of the reference.
6058 The temporaries created during the evaluation of the expression
6059 initializing the reference, except the temporary to which the
6060 reference is bound, are destroyed at the end of the
6061 full-expression in which they are created.
6063 In that case, we store the converted expression into a new
6064 VAR_DECL in a new scope.
6066 However, we want to be careful not to create temporaries when
6067 they are not required. For example, given:
6069 struct B {};
6070 struct D : public B {};
6071 D f();
6072 const B& b = f();
6074 there is no need to copy the return value from "f"; we can just
6075 extend its lifetime. Similarly, given:
6077 struct S {};
6078 struct T { operator S(); };
6079 T t;
6080 const S& s = t;
6082 we can extend the lifetime of the returnn value of the conversion
6083 operator. */
6086 {
6087 tree var;
6088 tree base_conv_type;
6090 /* Skip over the REF_BIND. */
6092 /* If the next conversion is a BASE_CONV, skip that too -- but
6093 remember that the conversion was required. */
6095 {
6098 }
6099 else
6101 /* Perform the remainder of the conversion. */
6104 {
6105 /* Create the temporary variable. */
6110 /* Use its address to initialize the reference variable. */
6112 }
6113 else
6114 /* Take the address of EXPR. */
6116 /* If a BASE_CONV was required, perform it now. */
6118 expr = (perform_implicit_conversion
6121 }
6123 /* Perform the conversion. */
6125 }