| blob | 44683ff5b83401eb929dd9bd2aa70d567654aaab |
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. */
50 #define convert_like(CONV, EXPR) \
51 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0)
52 #define convert_like_with_context(CONV, EXPR, FN, ARGNO) \
53 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. MSGSTR
2441 is the text to print before the candidate itself.
2443 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2444 to have been run through gettext by the caller. This wart makes
2445 life simpler in print_z_candidates and for the translators. */
2447 static void
2449 {
2451 {
2461 else
2464 }
2470 else
2473 }
2475 static void
2477 {
2482 /* There may be duplicates in the set of candidates. We put off
2483 checking this condition as long as possible, since we have no way
2484 to eliminate duplicates from a set of functions in less than n^2
2485 time. Now we are about to emit an error message, so it is more
2486 permissible to go slowly. */
2488 {
2490 /* Skip builtin candidates and conversion functions. */
2495 {
2499 else
2501 }
2502 }
2510 {
2511 /* Indent successive candidates by the width of the translation
2512 of the above string. */
2519 do
2520 {
2523 }
2525 }
2526 }
2528 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2529 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2530 the result of the conversion function to convert it to the final
2531 desired type. Merge the the two sequences into a single sequence,
2532 and return the merged sequence. */
2534 static tree
2536 {
2542 /* Find the end of the second conversion sequence. */
2547 /* Replace the identity conversion with the user conversion
2548 sequence. */
2551 /* The entire sequence is a user-conversion sequence. */
2555 }
2557 /* Returns the best overload candidate to perform the requested
2558 conversion. This function is used for three the overloading situations
2559 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2560 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2561 per [dcl.init.ref], so we ignore temporary bindings. */
2565 {
2572 /* We represent conversion within a hierarchy using RVALUE_CONV and
2573 BASE_CONV, as specified by [over.best.ics]; these become plain
2574 constructor calls, as specified in [dcl.init]. */
2580 complete_ctor_identifier,
2590 {
2591 tree t;
2598 /* We should never try to call the abstract or base constructor
2599 from here. */
2604 }
2606 {
2616 flags,
2617 DEDUCE_CALL);
2618 else
2622 flags);
2626 }
2632 {
2633 tree fns;
2637 /* If we are called to convert to a reference type, we are trying to
2638 find an lvalue binding, so don't even consider temporaries. If
2639 we don't find an lvalue binding, the caller will try again to
2640 look for a temporary binding. */
2645 {
2648 /* [over.match.funcs] For conversion functions, the function
2649 is considered to be a member of the class of the implicit
2650 object argument for the purpose of defining the type of
2651 the implicit object parameter.
2653 So we pass fromtype as CTYPE to add_*_candidate. */
2657 NULL_TREE,
2660 conversion_path,
2661 flags,
2662 DEDUCE_CONV);
2663 else
2665 args,
2667 conversion_path,
2668 flags);
2671 {
2682 }
2683 }
2684 }
2692 {
2694 {
2698 }
2705 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2706 ambiguous conversion is no worse than another user-defined
2707 conversion. */
2710 }
2712 /* Build the user conversion sequence. */
2713 convs = build_conv
2720 /* Combine it with the second conversion sequence. */
2728 }
2730 tree
2732 {
2737 {
2741 }
2743 }
2745 /* Find the possibly overloaded set of functions corresponding to a
2746 call of the form SCOPE::NAME (...). NAME might be a
2747 TEMPLATE_ID_EXPR, OVERLOAD, _DECL, IDENTIFIER_NODE or LOOKUP_EXPR. */
2749 tree
2751 {
2752 tree fn;
2757 {
2760 }
2768 else
2769 {
2772 {
2774 scope);
2776 }
2780 else
2783 fn = (adjust_result_of_qualified_name_lookup
2786 /* It might be the name of a function pointer member. */
2789 }
2792 {
2795 }
2797 {
2805 else
2807 }
2810 }
2812 /* Do any initial processing on the arguments to a function call. */
2814 static tree
2816 {
2817 tree t;
2819 {
2825 {
2828 }
2833 }
2835 }
2837 /* Perform overload resolution on FN, which is called with the ARGS.
2839 Return the candidate function selected by overload resolution, or
2840 NULL if the event that overload resolution failed. In the case
2841 that overload resolution fails, *CANDIDATES will be the set of
2842 candidates considered, and ANY_VIABLE_P will be set to true or
2843 false to indicate whether or not any of the candidates were
2844 viable.
2846 The ARGS should already have gone through RESOLVE_ARGS before this
2847 function is called. */
2851 tree args,
2854 {
2862 /* Check FN and ARGS. */
2872 {
2876 }
2878 /* Add the various candidate functions. */
2882 LOOKUP_NORMAL,
2883 candidates);
2891 }
2893 /* Return an expression for a call to FN (a namespace-scope function,
2894 or a static member function) with the ARGS. */
2896 tree
2898 {
2909 {
2917 else
2923 }
2926 }
2928 /* Build a call to a global operator new. FNNAME is the name of the
2929 operator (either "operator new" or "operator new[]") and ARGS are
2930 the arguments provided. *SIZE points to the total number of bytes
2931 required by the allocation, and is updated if that is changed here.
2932 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2933 function determins that no cookie should be used, after all,
2934 *COOKIE_SIZE is set to NULL_TREE. */
2936 tree
2938 {
2939 tree fns;
2951 /* Figure out what function is being called. */
2954 /* If no suitable function could be found, issue an error message
2955 and give up. */
2957 {
2961 else
2967 }
2969 /* If a cookie is required, add some extra space. Whether
2970 or not a cookie is required cannot be determined until
2971 after we know which function was called. */
2973 {
2976 {
2978 /* In G++ 3.2, the check was implemented incorrectly; it
2979 looked at the placement expression, rather than the
2980 type of the function. */
2983 ptr_type_node))
2985 }
2986 else
2987 {
2988 tree arg_types;
2991 /* Skip the size_t parameter. */
2993 /* Check the remaining parameters (if any). */
2997 ptr_type_node))
2999 }
3000 /* If we need a cookie, adjust the number of bytes allocated. */
3002 {
3003 /* Update the total size. */
3005 /* Update the argument list to reflect the adjusted size. */
3007 }
3008 else
3010 }
3012 /* Build the CALL_EXPR. */
3014 }
3016 static tree
3018 {
3025 {
3026 /* It's no good looking for an overloaded operator() on a
3027 pointer-to-member-function. */
3028 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3030 }
3042 {
3047 {
3055 else
3056 add_function_candidate
3059 }
3060 }
3065 {
3077 {
3080 add_template_conv_candidate
3084 else
3088 }
3089 }
3093 {
3097 }
3101 {
3105 }
3107 /* Since cand->fn will be a type, not a function, for a conversion
3108 function, we must be careful not to unconditionally look at
3109 DECL_NAME here. */
3114 obj = convert_like_with_context
3117 /* FIXME */
3119 }
3121 static void
3124 {
3129 else
3133 {
3150 else
3152 }
3153 }
3155 /* Return the implicit conversion sequence that could be used to
3156 convert E1 to E2 in [expr.cond]. */
3158 static tree
3160 {
3163 tree conv;
3165 /* [expr.cond]
3167 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3168 implicitly converted (clause _conv_) to the type "reference to
3169 T2", subject to the constraint that in the conversion the
3170 reference must bind directly (_dcl.init.ref_) to E1. */
3172 {
3174 t1,
3175 e1,
3176 LOOKUP_NO_TEMP_BIND);
3179 }
3181 /* [expr.cond]
3183 If E1 and E2 have class type, and the underlying class types are
3184 the same or one is a base class of the other: E1 can be converted
3185 to match E2 if the class of T2 is the same type as, or a base
3186 class of, the class of T1, and the cv-qualification of T2 is the
3187 same cv-qualification as, or a greater cv-qualification than, the
3188 cv-qualification of T1. If the conversion is applied, E1 is
3189 changed to an rvalue of type T2 that still refers to the original
3190 source class object (or the appropriate subobject thereof).
3192 FIXME we can't express an rvalue that refers to the original object;
3193 we have to create a new one. */
3197 {
3199 {
3203 {
3206 }
3207 else
3210 }
3211 else
3213 }
3215 /* [expr.cond]
3217 E1 can be converted to match E2 if E1 can be implicitly converted
3218 to the type that expression E2 would have if E2 were converted to
3219 an rvalue (or the type it has, if E2 is an rvalue). */
3221 }
3223 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3224 arguments to the conditional expression. */
3226 tree
3228 {
3229 tree arg2_type;
3230 tree arg3_type;
3231 tree result;
3237 /* As a G++ extension, the second argument to the conditional can be
3238 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3239 c'.) If the second operand is omitted, make sure it is
3240 calculated only once. */
3242 {
3246 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3249 else
3251 }
3253 /* [expr.cond]
3255 The first expr ession is implicitly converted to bool (clause
3256 _conv_). */
3259 /* If something has already gone wrong, just pass that fact up the
3260 tree. */
3269 /* [expr.cond]
3271 If either the second or the third operand has type (possibly
3272 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3273 array-to-pointer (_conv.array_), and function-to-pointer
3274 (_conv.func_) standard conversions are performed on the second
3275 and third operands. */
3279 {
3280 /* Do the conversions. We don't these for `void' type arguments
3281 since it can't have any effect and since decay_conversion
3282 does not handle that case gracefully. */
3290 /* [expr.cond]
3292 One of the following shall hold:
3294 --The second or the third operand (but not both) is a
3295 throw-expression (_except.throw_); the result is of the
3296 type of the other and is an rvalue.
3298 --Both the second and the third operands have type void; the
3299 result is of type void and is an rvalue. */
3306 else
3307 {
3311 }
3315 }
3316 /* [expr.cond]
3318 Otherwise, if the second and third operand have different types,
3319 and either has (possibly cv-qualified) class type, an attempt is
3320 made to convert each of those operands to the type of the other. */
3323 {
3327 /* [expr.cond]
3329 If both can be converted, or one can be converted but the
3330 conversion is ambiguous, the program is ill-formed. If
3331 neither can be converted, the operands are left unchanged and
3332 further checking is performed as described below. If exactly
3333 one conversion is possible, that conversion is applied to the
3334 chosen operand and the converted operand is used in place of
3335 the original operand for the remainder of this section. */
3340 {
3343 }
3345 {
3351 }
3353 {
3359 }
3360 }
3362 /* [expr.cond]
3364 If the second and third operands are lvalues and have the same
3365 type, the result is of that type and is an lvalue. */
3368 {
3371 }
3373 /* [expr.cond]
3375 Otherwise, the result is an rvalue. If the second and third
3376 operand do not have the same type, and either has (possibly
3377 cv-qualified) class type, overload resolution is used to
3378 determine the conversions (if any) to be applied to the operands
3379 (_over.match.oper_, _over.built_). */
3383 {
3385 tree conv;
3388 /* Rearrange the arguments so that add_builtin_candidate only has
3389 to know about two args. In build_builtin_candidates, the
3390 arguments are unscrambled. */
3395 COND_EXPR,
3396 NOP_EXPR,
3398 args,
3399 LOOKUP_NORMAL);
3401 /* [expr.cond]
3403 If the overload resolution fails, the program is
3404 ill-formed. */
3407 {
3411 }
3414 {
3418 }
3420 /* [expr.cond]
3422 Otherwise, the conversions thus determined are applied, and
3423 the converted operands are used in place of the original
3424 operands for the remainder of this section. */
3431 }
3433 /* [expr.cond]
3435 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3436 and function-to-pointer (_conv.func_) standard conversions are
3437 performed on the second and third operands.
3439 We need to force the lvalue-to-rvalue conversion here for class types,
3440 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3441 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3442 regions.
3444 We use ocp_convert rather than build_user_type_conversion because the
3445 latter returns NULL_TREE on failure, while the former gives an error. */
3456 /* [expr.cond]
3458 After those conversions, one of the following shall hold:
3460 --The second and third operands have the same type; the result is of
3461 that type. */
3464 /* [expr.cond]
3466 --The second and third operands have arithmetic or enumeration
3467 type; the usual arithmetic conversions are performed to bring
3468 them to a common type, and the result is of that type. */
3473 {
3474 /* In this case, there is always a common type. */
3476 arg3_type);
3491 }
3492 /* [expr.cond]
3494 --The second and third operands have pointer type, or one has
3495 pointer type and the other is a null pointer constant; pointer
3496 conversions (_conv.ptr_) and qualification conversions
3497 (_conv.qual_) are performed to bring them to their composite
3498 pointer type (_expr.rel_). The result is of the composite
3499 pointer type.
3501 --The second and third operands have pointer to member type, or
3502 one has pointer to member type and the other is a null pointer
3503 constant; pointer to member conversions (_conv.mem_) and
3504 qualification conversions (_conv.qual_) are performed to bring
3505 them to a common type, whose cv-qualification shall match the
3506 cv-qualification of either the second or the third operand.
3507 The result is of the common type. */
3518 {
3523 }
3526 {
3529 }
3531 valid_operands:
3533 /* Expand both sides into the same slot, hopefully the target of the
3534 ?: expression. We used to check for TARGET_EXPRs here, but now we
3535 sometimes wrap them in NOP_EXPRs so the test would fail. */
3539 /* If this expression is an rvalue, but might be mistaken for an
3540 lvalue, we must add a NON_LVALUE_EXPR. */
3545 }
3547 /* OPERAND is an operand to an expression. Perform necessary steps
3548 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3549 returned. */
3551 static tree
3553 {
3555 {
3561 /* Make sure the template type is instantiated now. */
3563 }
3566 }
3568 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3569 OVERLOAD) to the CANDIDATES, returning an updated list of
3570 CANDIDATES. The ARGS are the arguments provided to the call,
3571 without any implicit object parameter. The EXPLICIT_TARGS are
3572 explicit template arguments provided. TEMPLATE_ONLY is true if
3573 only template fucntions should be considered. CONVERSION_PATH,
3574 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3576 static void
3582 {
3583 tree ctype;
3584 tree non_static_args;
3587 /* Delay creating the implicit this parameter until it is needed. */
3591 {
3592 tree fn;
3593 tree fn_args;
3596 /* Figure out which set of arguments to use. */
3598 {
3599 /* If this function is a non-static member, prepend the implicit
3600 object parameter. */
3606 }
3607 else
3608 /* Otherwise, just use the list of arguments provided. */
3613 fn,
3614 ctype,
3615 explicit_targs,
3616 fn_args,
3617 NULL_TREE,
3618 access_path,
3619 conversion_path,
3620 flags,
3621 DEDUCE_CALL);
3624 fn,
3625 ctype,
3626 fn_args,
3627 access_path,
3628 conversion_path,
3629 flags);
3631 }
3632 }
3634 tree
3636 {
3641 tree conv;
3651 {
3655 }
3656 else
3662 {
3667 /* Use build_op_new_call and build_op_delete_call instead. */
3675 }
3681 {
3688 }
3703 /* Add namespace-scope operators to the list of functions to
3704 consider. */
3708 /* Add class-member operators to the candidate set. */
3710 {
3711 tree fns;
3722 }
3724 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3725 to know about two args; a builtin candidate will always have a first
3726 parameter of type bool. We'll handle that in
3727 build_builtin_candidate. */
3729 {
3733 }
3734 else
3735 {
3739 }
3744 {
3747 /* For these, the built-in candidates set is empty
3748 [over.match.oper]/3. We don't want non-strict matches
3749 because exact matches are always possible with built-in
3750 operators. The built-in candidate set for COMPONENT_REF
3751 would be empty too, but since there are no such built-in
3752 operators, we accept non-strict matches for them. */
3759 }
3763 {
3765 {
3768 /* Look for an `operator++ (int)'. If they didn't have
3769 one, then we fall back to the old way of doing things. */
3772 fnname,
3776 else
3780 /* The caller will deal with these. */
3788 }
3790 {
3793 }
3795 }
3799 {
3801 {
3804 }
3806 }
3809 {
3815 {
3819 cand == candidates
3822 }
3825 }
3827 /* Check for comparison of different enum types. */
3829 {
3840 {
3843 }
3847 }
3849 /* We need to strip any leading REF_BIND so that bitfields don't cause
3850 errors. This should not remove any important conversions, because
3851 builtins don't apply to class objects directly. */
3857 {
3862 }
3864 {
3869 }
3871 builtin:
3873 {
3921 return build_m_component_ref
3924 /* The caller will deal with these. */
3933 }
3934 }
3936 /* Build a call to operator delete. This has to be handled very specially,
3937 because the restrictions on what signatures match are different from all
3938 other call instances. For a normal delete, only a delete taking (void *)
3939 or (void *, size_t) is accepted. For a placement delete, only an exact
3940 match with the placement new is accepted.
3942 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3943 ADDR is the pointer to be deleted.
3944 SIZE is the size of the memory block to be deleted.
3945 FLAGS are the usual overloading flags.
3946 PLACEMENT is the corresponding placement new call, or NULL_TREE. */
3948 tree
3951 {
3966 /* In [class.free]
3968 If the result of the lookup is ambiguous or inaccessible, or if
3969 the lookup selects a placement deallocation function, the
3970 program is ill-formed.
3972 Therefore, we ask lookup_fnfields to complain ambout ambiguity. */
3973 {
3977 }
3978 else
3985 {
3986 tree alloc_fn;
3987 tree call_expr;
3989 /* Find the allocation function that is being called. */
3991 /* Sometimes we have a COMPOUND_EXPR, rather than a simple
3992 CALL_EXPR. */
3995 /* Extract the function. */
3998 /* Then the second parm type. */
4000 /* Also the second argument. */
4002 }
4003 else
4004 {
4005 /* First try it without the size argument. */
4008 }
4010 /* Strip const and volatile from addr. */
4013 /* We make two tries at finding a matching `operator delete'. On
4014 the first pass, we look for an one-operator (or placement)
4015 operator delete. If we're not doing placement delete, then on
4016 the second pass we look for a two-argument delete. */
4018 {
4021 else
4022 /* Normal delete; now try to find a match including the size
4023 argument. */
4026 void_list_node));
4029 /* Go through the `operator delete' functions looking for one
4030 with a matching type. */
4032 fn;
4034 {
4035 tree t;
4037 /* Exception specifications on the `delete' operator do not
4038 matter. */
4040 NULL_TREE);
4041 /* We also don't compare attributes. We're really just
4042 trying to check the types of the first two parameters. */
4045 }
4047 /* If we found a match, we're done. */
4050 }
4052 /* If we have a matching function, call it. */
4054 {
4055 /* Make sure we have the actual function, and not an
4056 OVERLOAD. */
4059 /* If the FN is a member function, make sure that it is
4060 accessible. */
4066 else
4071 }
4073 /* If we are doing placement delete we do nothing if we don't find a
4074 matching op delete. */
4080 }
4082 /* If the current scope isn't allowed to access DECL along
4083 BASETYPE_PATH, give an error. The most derived class in
4084 BASETYPE_PATH is the one used to qualify DECL. */
4086 bool
4088 {
4090 {
4095 else
4099 }
4102 }
4104 /* Perform the conversions in CONVS on the expression EXPR.
4105 FN and ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4106 indicates the `this' argument of a method. INNER is nonzero when
4107 being called to continue a conversion chain. It is negative when a
4108 reference binding will be applied, positive otherwise. */
4110 static tree
4112 {
4121 {
4124 {
4126 {
4129 }
4134 }
4139 }
4142 expr = dubious_conversion_warnings
4145 {
4147 {
4150 tree args;
4153 {
4160 /* We should never try to call the abstract or base constructor
4161 from here. */
4164 }
4165 else
4169 /* If this is a constructor or a function returning an aggr type,
4170 we need to build up a TARGET_EXPR. */
4174 /* The result of the call is then used to direct-initialize the object
4175 that is the destination of the copy-initialization. [dcl.init]
4177 Note that this step is not reflected in the conversion sequence;
4178 it affects the semantics when we actually perform the
4179 conversion, but is not considered during overload resolution.
4181 If the target is a class, that means call a ctor. */
4184 {
4186 expr = build_special_member_call
4189 /* Core issue 84, now a DR, says that we don't allow UDCs
4190 for these args (which deliberately breaks copy-init of an
4191 auto_ptr<Base> from an auto_ptr<Derived>). */
4194 /* Tell the user where this failing constructor call came from. */
4196 {
4198 warning
4202 error
4205 }
4206 else
4207 {
4210 convfn);
4213 convfn);
4214 }
4216 }
4218 }
4222 /* Convert a non-array constant variable to its underlying value, unless we
4223 are about to bind it to a reference, in which case we need to
4224 leave it as an lvalue. */
4230 /* Call build_user_type_conversion again for the error. */
4231 return build_user_type_conversion
4236 };
4244 {
4248 /* else fall through */
4251 {
4252 /* We are going to bind a reference directly to a base-class
4253 subobject of EXPR. */
4256 /* Build an expression for `*((base*) &expr)'. */
4261 }
4263 /* Copy-initialization where the cv-unqualified version of the source
4264 type is the same class as, or a derived class of, the class of the
4265 destination [is treated as direct-initialization]. [dcl.init] */
4272 {
4277 }
4281 {
4284 /* If necessary, create a temporary. */
4286 {
4289 }
4291 /* Take the address of the thing to which we will bind the
4292 reference. */
4297 /* Convert it to a pointer to the type referred to by the
4298 reference. This will adjust the pointer if a derived to
4299 base conversion is being performed. */
4301 expr);
4302 /* Convert the pointer to the desired reference type. */
4304 }
4310 /* Warn about deprecated conversion if appropriate. */
4316 }
4319 }
4321 /* Build a call to __builtin_trap which can be used in an expression. */
4323 static tree
4325 {
4329 else
4335 }
4337 /* ARG is being passed to a varargs function. Perform any conversions
4338 required. Array/function to pointer decay must have already happened.
4339 Return the converted value. */
4341 tree
4343 {
4347 /* Convert `float' to `double'. */
4349 else
4350 /* Convert `short' and `char' to full-size `int'. */
4356 {
4357 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4358 here and do a bitwise copy, but now cp_expr_size will abort if we
4359 try to do that. */
4364 }
4367 }
4369 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4371 tree
4373 {
4383 {
4384 /* Undefined behavior [expr.call] 5.2.2/7. */
4386 type);
4387 }
4390 }
4392 /* TYPE has been given to va_arg. Apply the default conversions which
4393 would have happened when passed via ellipsis. Return the promoted
4394 type, or the passed type if there is no change. */
4396 tree
4398 {
4399 tree promote;
4412 }
4414 /* ARG is a default argument expression being passed to a parameter of
4415 the indicated TYPE, which is a parameter to FN. Do any required
4416 conversions. Return the converted value. */
4418 tree
4420 {
4421 /* If the ARG is an unparsed default argument expression, the
4422 conversion cannot be performed. */
4424 {
4429 }
4437 {
4441 }
4442 else
4443 {
4444 /* This could get clobbered by the following call. */
4451 }
4454 }
4456 /* Returns the type which will really be used for passing an argument of
4457 type TYPE. */
4459 tree
4461 {
4462 /* Pass classes with copy ctors by invisible reference. */
4471 }
4473 /* Actually perform the appropriate conversion. */
4475 tree
4477 {
4479 ;
4480 /* Pass classes with copy ctors by invisible reference. */
4488 }
4490 /* Subroutine of the various build_*_call functions. Overload resolution
4491 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4492 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4493 bitmask of various LOOKUP_* flags which apply to the call itself. */
4495 static tree
4497 {
4507 /* Give any warnings we noticed during overload resolution. */
4519 /* The implicit parameters to a constructor are not considered by overload
4520 resolution, and must be of the proper type. */
4522 {
4527 /* We should never try to call the abstract constructor. */
4530 {
4531 converted_args = tree_cons
4535 }
4536 }
4537 /* Bypass access control for 'this' parameter. */
4539 {
4542 tree converted_arg;
4543 tree base_binfo;
4549 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4550 X is called for an object that is not of type X, or of a type
4551 derived from X, the behavior is undefined.
4553 So we can assume that anything passed as 'this' is non-null, and
4554 optimize accordingly. */
4556 /* Convert to the base in which the function was declared. */
4562 /* If fn was found by a using declaration, the conversion path
4563 will be to the derived class, not the base declaring fn. We
4564 must convert from derived to base. */
4576 }
4580 {
4584 val = convert_like_with_context
4589 }
4591 /* Default arguments */
4593 converted_args
4598 converted_args);
4600 /* Ellipsis */
4602 converted_args
4605 converted_args);
4611 converted_args);
4613 /* Avoid actually calling copy constructors and copy assignment operators,
4614 if possible. */
4620 {
4621 tree targ;
4625 /* Pull out the real argument, disregarding const-correctness. */
4632 {
4637 }
4638 else
4643 else
4646 /* [class.copy]: the copy constructor is implicitly defined even if
4647 the implementation elided its use. */
4651 /* If we're creating a temp and we already have one, don't create a
4652 new one. If we're not creating a temp but we get one, use
4653 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4654 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4655 temp or an INIT_EXPR otherwise. */
4657 {
4662 }
4665 {
4666 tree address;
4667 tree to = stabilize_reference
4672 /* Avoid a warning about this expression, if the address is
4673 never used. */
4676 }
4677 }
4681 {
4682 tree to = stabilize_reference
4688 }
4693 {
4706 else
4709 }
4712 else
4716 }
4718 /* Build and return a call to FN, using the the CONVERTED_ARGS. ARGS
4719 gives the original form of the arguments. This function performs
4720 no overload resolution, conversion, or other high-level
4721 operations. */
4723 tree
4725 {
4726 tree fndecl;
4728 /* Recognize certain built-in functions so we can make tree-codes
4729 other than CALL_EXPR. We do this when it enables fold-const.c
4730 to do something useful. */
4734 {
4735 tree exp;
4739 }
4743 /* If this call might throw an exception, note that fact. */
4750 /* Some built-in function calls will be evaluated at compile-time in
4751 fold (). */
4764 }
4768 /* Make an expression which yields the address of the Java interface
4769 method FN. This is achieved by generating a call to libjava's
4770 _Jv_LookupInterfaceMethodIdx(). */
4772 static tree
4774 {
4780 {
4785 endlink)));
4786 java_iface_lookup_fn
4790 }
4792 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
4793 This is the first entry in the vtable. */
4795 integer_zero_node);
4797 /* Get the java.lang.Class pointer for the interface being called. */
4802 {
4804 iface);
4806 }
4809 /* Determine the itable index of FN. */
4812 {
4817 i++;
4818 }
4826 java_iface_lookup_fn);
4828 }
4830 /* Returns the value to use for the in-charge parameter when making a
4831 call to a function with the indicated NAME. */
4833 tree
4835 {
4846 /* This function should only be called with one of the names listed
4847 above. */
4850 }
4852 /* Build a call to a constructor, destructor, or an assignment
4853 operator for INSTANCE, an expression with class type. NAME
4854 indicates the special member function to call; ARGS are the
4855 arguments. BINFO indicates the base of INSTANCE that is to be
4856 passed as the `this' parameter to the member function called.
4858 FLAGS are the LOOKUP_* flags to use when processing the call.
4860 If NAME indicates a complete object constructor, INSTANCE may be
4861 NULL_TREE. In this case, the caller will call build_cplus_new to
4862 store the newly constructed object into a VAR_DECL. */
4864 tree
4867 {
4868 tree fns;
4869 /* The type of the subobject to be constructed or destroyed. */
4870 tree class_type;
4883 /* Handle the special case where INSTANCE is NULL_TREE. */
4885 {
4889 }
4897 /* Resolve the name. */
4903 /* When making a call to a constructor or destructor for a subobject
4904 that uses virtual base classes, pass down a pointer to a VTT for
4905 the subobject. */
4909 {
4910 tree vtt;
4911 tree sub_vtt;
4913 /* If the current function is a complete object constructor
4914 or destructor, then we fetch the VTT directly.
4915 Otherwise, we look it up using the VTT we were given. */
4921 current_vtt_parm,
4922 vtt);
4928 }
4931 }
4933 /* Return the NAME, as a C string. The NAME indicates a function that
4934 is a member of TYPE. *FREE_P is set to true if the caller must
4935 free the memory returned.
4937 Rather than go through all of this, we should simply set the names
4938 of constructors and destructors appropriately, and dispense with
4939 ctor_identifier, dtor_identifier, etc. */
4943 {
4946 /* Assume that we will not allocate memory. */
4948 /* Constructors and destructors are special. */
4950 {
4951 pretty_name
4953 /* For a destructor, add the '~'. */
4957 {
4959 /* Remember that we need to free the memory allocated. */
4961 }
4962 }
4963 else
4967 }
4969 /* Build a call to "INSTANCE.FN (ARGS)". */
4971 tree
4974 {
4978 tree access_binfo;
4979 tree optype;
4981 tree name;
4982 tree user_args;
4983 tree call;
4984 tree fn;
4985 tree class_type;
4996 /* Process the argument list. */
5010 {
5016 }
5025 {
5029 }
5036 /* XXX this should be handled before we get here. */
5038 {
5044 }
5050 {
5051 /* Callers should explicitly indicate whether they want to construct
5052 the complete object or just the part without virtual bases. */
5054 /* Similarly for destructors. */
5056 }
5058 /* It's OK to call destructors on cv-qualified objects. Therefore,
5059 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5061 {
5065 }
5071 {
5073 tree this_arglist;
5075 /* We can end up here for copy-init of same or base class. */
5082 else
5086 /* A member template. */
5088 class_type,
5089 explicit_targs,
5091 access_binfo,
5092 conversion_path,
5093 flags,
5094 DEDUCE_CALL);
5097 class_type,
5098 this_arglist,
5099 access_binfo,
5100 conversion_path,
5101 flags);
5102 }
5106 {
5107 /* XXX will LOOKUP_SPECULATIVELY be needed when this is done? */
5112 else
5113 {
5123 }
5126 }
5130 {
5136 user_args);
5141 }
5150 "abstract virtual `%#D' called from constructor"
5155 {
5158 }
5166 else
5167 {
5169 /* In an expression of the form `a->f()' where `f' turns out to
5170 be a static member function, `a' is none-the-less evaluated. */
5173 }
5176 }
5178 /* Returns true iff standard conversion sequence ICS1 is a proper
5179 subsequence of ICS2. */
5181 static bool
5183 {
5184 /* We can assume that a conversion of the same code
5185 between the same types indicates a subsequence since we only get
5186 here if the types we are converting from are the same. */
5193 {
5201 /* At this point, ICS1 cannot be a proper subsequence of
5202 ICS2. We can get a USER_CONV when we are comparing the
5203 second standard conversion sequence of two user conversion
5204 sequences. */
5214 }
5215 }
5217 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5218 be any _TYPE nodes. */
5220 bool
5222 {
5227 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5228 considers every class derived from itself. */
5231 }
5233 /* We build the ICS for an implicit object parameter as a pointer
5234 conversion sequence. However, such a sequence should be compared
5235 as if it were a reference conversion sequence. If ICS is the
5236 implicit conversion sequence for an implicit object parameter,
5237 modify it accordingly. */
5239 static void
5241 {
5243 {
5244 /* [over.match.funcs]
5246 For non-static member functions, the type of the
5247 implicit object parameter is "reference to cv X"
5248 where X is the class of which the function is a
5249 member and cv is the cv-qualification on the member
5250 function declaration. */
5252 tree reference_type;
5254 /* The `this' parameter is a pointer to a class type. Make the
5255 implict conversion talk about a reference to that same class
5256 type. */
5267 }
5268 }
5270 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5271 and return the type to which the reference refers. Otherwise,
5272 leave *ICS unchanged and return NULL_TREE. */
5274 static tree
5276 {
5278 {
5285 }
5288 }
5290 /* Compare two implicit conversion sequences according to the rules set out in
5291 [over.ics.rank]. Return values:
5293 1: ics1 is better than ics2
5294 -1: ics2 is better than ics1
5295 0: ics1 and ics2 are indistinguishable */
5297 static int
5299 {
5300 tree from_type1;
5301 tree from_type2;
5302 tree to_type1;
5303 tree to_type2;
5310 /* REF_BINDING is nonzero if the result of the conversion sequence
5311 is a reference type. In that case TARGET_TYPE is the
5312 type referred to by the reference. */
5313 tree target_type1;
5314 tree target_type2;
5316 /* Handle implicit object parameters. */
5320 /* Handle reference parameters. */
5324 /* [over.ics.rank]
5326 When comparing the basic forms of implicit conversion sequences (as
5327 defined in _over.best.ics_)
5329 --a standard conversion sequence (_over.ics.scs_) is a better
5330 conversion sequence than a user-defined conversion sequence
5331 or an ellipsis conversion sequence, and
5333 --a user-defined conversion sequence (_over.ics.user_) is a
5334 better conversion sequence than an ellipsis conversion sequence
5335 (_over.ics.ellipsis_). */
5345 {
5346 /* XXX Isn't this an extension? */
5347 /* Both ICS are bad. We try to make a decision based on what
5348 would have happenned if they'd been good. */
5356 /* We couldn't make up our minds; try to figure it out below. */
5357 }
5360 /* Both conversions are ellipsis conversions. */
5363 /* User-defined conversion sequence U1 is a better conversion sequence
5364 than another user-defined conversion sequence U2 if they contain the
5365 same user-defined conversion operator or constructor and if the sec-
5366 ond standard conversion sequence of U1 is better than the second
5367 standard conversion sequence of U2. */
5370 {
5383 /* We can just fall through here, after setting up
5384 FROM_TYPE1 and FROM_TYPE2. */
5387 }
5388 else
5389 {
5390 /* We're dealing with two standard conversion sequences.
5392 [over.ics.rank]
5394 Standard conversion sequence S1 is a better conversion
5395 sequence than standard conversion sequence S2 if
5397 --S1 is a proper subsequence of S2 (comparing the conversion
5398 sequences in the canonical form defined by _over.ics.scs_,
5399 excluding any Lvalue Transformation; the identity
5400 conversion sequence is considered to be a subsequence of
5401 any non-identity conversion sequence */
5412 }
5415 {
5420 }
5421 /* Otherwise, one sequence cannot be a subsequence of the other; they
5422 don't start with the same type. This can happen when comparing the
5423 second standard conversion sequence in two user-defined conversion
5424 sequences. */
5426 /* [over.ics.rank]
5428 Or, if not that,
5430 --the rank of S1 is better than the rank of S2 (by the rules
5431 defined below):
5433 Standard conversion sequences are ordered by their ranks: an Exact
5434 Match is a better conversion than a Promotion, which is a better
5435 conversion than a Conversion.
5437 Two conversion sequences with the same rank are indistinguishable
5438 unless one of the following rules applies:
5440 --A conversion that is not a conversion of a pointer, or pointer
5441 to member, to bool is better than another conversion that is such
5442 a conversion.
5444 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5445 so that we do not have to check it explicitly. */
5458 {
5463 }
5464 /* The rules for pointers to members A::* are just like the rules
5465 for pointers A*, except opposite: if B is derived from A then
5466 A::* converts to B::*, not vice versa. For that reason, we
5467 switch the from_ and to_ variables here. */
5472 {
5477 }
5482 {
5487 }
5492 {
5493 /* This was one of the pointer or pointer-like conversions.
5495 [over.ics.rank]
5497 --If class B is derived directly or indirectly from class A,
5498 conversion of B* to A* is better than conversion of B* to
5499 void*, and conversion of A* to void* is better than
5500 conversion of B* to void*. */
5503 {
5505 deref_from_type2))
5508 deref_from_type1))
5510 }
5513 {
5515 {
5517 {
5519 deref_to_type1))
5521 }
5522 /* We know that DEREF_TO_TYPE1 is `void' here. */
5524 deref_to_type2))
5526 }
5527 }
5530 {
5531 /* [over.ics.rank]
5533 --If class B is derived directly or indirectly from class A
5534 and class C is derived directly or indirectly from B,
5536 --conversion of C* to B* is better than conversion of C* to
5537 A*,
5539 --conversion of B* to A* is better than conversion of C* to
5540 A* */
5542 {
5544 deref_to_type2))
5547 deref_to_type1))
5549 }
5551 {
5553 deref_from_type1))
5556 deref_from_type2))
5558 }
5559 }
5560 }
5563 {
5566 /* [over.ics.rank]
5568 --binding of an expression of type C to a reference of type
5569 B& is better than binding an expression of type C to a
5570 reference of type A&
5572 --conversion of C to B is better than conversion of C to A, */
5575 {
5580 }
5581 }
5584 {
5587 /* [over.ics.rank]
5589 --binding of an expression of type B to a reference of type
5590 A& is better than binding an expression of type C to a
5591 reference of type A&,
5593 --onversion of B to A is better than conversion of C to A */
5596 {
5601 }
5602 }
5604 /* [over.ics.rank]
5606 --S1 and S2 differ only in their qualification conversion and yield
5607 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5608 qualification signature of type T1 is a proper subset of the cv-
5609 qualification signature of type T2 */
5615 /* [over.ics.rank]
5617 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5618 types to which the references refer are the same type except for
5619 top-level cv-qualifiers, and the type to which the reference
5620 initialized by S2 refers is more cv-qualified than the type to
5621 which the reference initialized by S1 refers */
5627 /* Neither conversion sequence is better than the other. */
5629 }
5631 /* The source type for this standard conversion sequence. */
5633 static tree
5635 {
5637 {
5642 }
5644 }
5646 /* Note a warning about preferring WINNER to LOSER. We do this by storing
5647 a pointer to LOSER and re-running joust to produce the warning if WINNER
5648 is actually used. */
5650 static void
5652 {
5656 }
5658 /* Compare two candidates for overloading as described in
5659 [over.match.best]. Return values:
5661 1: cand1 is better than cand2
5662 -1: cand2 is better than cand1
5663 0: cand1 and cand2 are indistinguishable */
5665 static int
5667 {
5671 /* Candidates that involve bad conversions are always worse than those
5672 that don't. */
5678 /* If we have two pseudo-candidates for conversions to the same type,
5679 or two candidates for the same function, arbitrarily pick one. */
5684 /* a viable function F1
5685 is defined to be a better function than another viable function F2 if
5686 for all arguments i, ICSi(F1) is not a worse conversion sequence than
5687 ICSi(F2), and then */
5689 /* for some argument j, ICSj(F1) is a better conversion sequence than
5690 ICSj(F2) */
5692 /* For comparing static and non-static member functions, we ignore
5693 the implicit object parameter of the non-static function. The
5694 standard says to pretend that the static function has an object
5695 parm, but that won't work with operator overloading. */
5698 {
5704 {
5707 }
5708 else
5710 }
5713 {
5719 {
5731 {
5738 else
5743 {
5747 }
5748 else
5750 }
5753 {
5756 }
5758 }
5759 }
5761 /* warn about confusing overload resolution for user-defined conversions,
5762 either between a constructor and a conversion op, or between two
5763 conversion ops. */
5767 {
5773 else
5776 /* We don't want to complain about `X::operator T1 ()'
5777 beating `X::operator T2 () const', when T2 is a no less
5778 cv-qualified version of T1. */
5781 {
5786 {
5789 }
5792 }
5793 else
5799 {
5807 }
5808 else
5810 }
5815 /* or, if not that,
5816 F1 is a non-template function and F2 is a template function
5817 specialization. */
5824 /* or, if not that,
5825 F1 and F2 are template functions and the function template for F1 is
5826 more specialized than the template for F2 according to the partial
5827 ordering rules. */
5830 {
5831 winner = more_specialized
5833 DEDUCE_ORDER,
5834 /* Tell the deduction code how many real function arguments
5835 we saw, not counting the implicit 'this' argument. But,
5836 add_function_candidate() suppresses the "this" argument
5837 for constructors.
5839 [temp.func.order]: The presence of unused ellipsis and default
5840 arguments has no effect on the partial ordering of function
5841 templates. */
5847 }
5849 /* or, if not that,
5850 the context is an initialization by user-defined conversion (see
5851 _dcl.init_ and _over.match.user_) and the standard conversion
5852 sequence from the return type of F1 to the destination type (i.e.,
5853 the type of the entity being initialized) is a better conversion
5854 sequence than the standard conversion sequence from the return type
5855 of F2 to the destination type. */
5858 {
5862 }
5864 /* Check whether we can discard a builtin candidate, either because we
5865 have two identical ones or matching builtin and non-builtin candidates.
5867 (Pedantically in the latter case the builtin which matched the user
5868 function should not be added to the overload set, but we spot it here.
5870 [over.match.oper]
5871 ... the builtin candidates include ...
5872 - do not have the same parameter type list as any non-template
5873 non-member candidate. */
5877 {
5883 {
5885 /* Two built-in candidates; arbitrarily pick one. */
5888 /* cand1 is built-in; prefer cand2. */
5890 else
5891 /* cand2 is built-in; prefer cand1. */
5893 }
5894 }
5896 /* If the two functions are the same (this can happen with declarations
5897 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
5902 tweak:
5904 /* Extension: If the worst conversion for one candidate is worse than the
5905 worst conversion for the other, take the first. */
5907 {
5912 {
5917 }
5923 {
5925 {
5927 ISO C++ says that these are ambiguous, even \
5928 though the worst conversion for the first is better than \
5932 }
5933 else
5936 }
5937 }
5941 }
5943 /* Given a list of candidates for overloading, find the best one, if any.
5944 This algorithm has a worst case of O(2n) (winner is last), and a best
5945 case of O(n/2) (totally ambiguous); much better than a sorting
5946 algorithm. */
5950 {
5955 /* Walk through the list once, comparing each current champ to the next
5956 candidate, knocking out a candidate or two with each comparison. */
5959 {
5963 else
5964 {
5966 {
5971 }
5972 else
5973 {
5976 }
5979 }
5980 }
5982 /* Make sure the champ is better than all the candidates it hasn't yet
5983 been compared to. */
5986 challenger != champ
5989 {
5993 }
5996 }
5998 /* Returns nonzero if things of type FROM can be converted to TO. */
6000 bool
6002 {
6004 }
6006 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6008 bool
6010 {
6013 }
6015 /* Like can_convert_arg, but allows dubious conversions as well. */
6017 bool
6019 {
6021 }
6023 /* Convert EXPR to TYPE. Return the converted expression.
6025 Note that we allow bad conversions here because by the time we get to
6026 this point we are committed to doing the conversion. If we end up
6027 doing a bad conversion, convert_like will complain. */
6029 tree
6031 {
6032 tree conv;
6037 LOOKUP_NORMAL);
6039 {
6042 }
6045 }
6047 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6048 is being bound to a temporary. Create and return a new VAR_DECL
6049 with the indicated TYPE; this variable will store the value to
6050 which the reference is bound. */
6052 tree
6054 {
6055 tree var;
6057 /* Create the variable. */
6062 /* Register the variable. */
6064 {
6065 /* Namespace-scope or local static; give it a mangled name. */
6066 tree name;
6073 }
6074 else
6075 {
6076 /* Create a new cleanup level if necessary. */
6078 /* Don't push unnamed temps. Do set DECL_CONTEXT, though. */
6080 }
6083 }
6085 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6086 initializing a variable of that TYPE. If DECL is non-NULL, it is
6087 the VAR_DECL being initialized with the EXPR. (In that case, the
6088 type of DECL will be TYPE.)
6090 Return the converted expression. */
6092 tree
6094 {
6095 tree conv;
6102 {
6105 }
6107 /* If DECL is non-NULL, then this special rule applies:
6109 [class.temporary]
6111 The temporary to which the reference is bound or the temporary
6112 that is the complete object to which the reference is bound
6113 persists for the lifetime of the reference.
6115 The temporaries created during the evaluation of the expression
6116 initializing the reference, except the temporary to which the
6117 reference is bound, are destroyed at the end of the
6118 full-expression in which they are created.
6120 In that case, we store the converted expression into a new
6121 VAR_DECL in a new scope.
6123 However, we want to be careful not to create temporaries when
6124 they are not required. For example, given:
6126 struct B {};
6127 struct D : public B {};
6128 D f();
6129 const B& b = f();
6131 there is no need to copy the return value from "f"; we can just
6132 extend its lifetime. Similarly, given:
6134 struct S {};
6135 struct T { operator S(); };
6136 T t;
6137 const S& s = t;
6139 we can extend the lifetime of the returnn value of the conversion
6140 operator. */
6143 {
6144 tree var;
6145 tree base_conv_type;
6147 /* Skip over the REF_BIND. */
6149 /* If the next conversion is a BASE_CONV, skip that too -- but
6150 remember that the conversion was required. */
6152 {
6155 }
6156 else
6158 /* Perform the remainder of the conversion. */
6161 {
6162 /* Create the temporary variable. */
6167 /* Use its address to initialize the reference variable. */
6169 }
6170 else
6171 /* Take the address of EXPR. */
6173 /* If a BASE_CONV was required, perform it now. */
6175 expr = (perform_implicit_conversion
6178 }
6180 /* Perform the conversion. */
6182 }