| blob | 34187039243affbc6b0da6a6686f9e87b9bd77db |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 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, 51 Franklin Street, Fifth Floor,
22 Boston, MA 02110-1301, USA. */
25 /* High-level class interface. */
44 /* The various kinds of conversion. */
47 ck_identity,
48 ck_lvalue,
49 ck_qual,
50 ck_std,
51 ck_ptr,
52 ck_pmem,
53 ck_base,
54 ck_ref_bind,
55 ck_user,
56 ck_ambig,
57 ck_rvalue
60 /* The rank of the conversion. Order of the enumerals matters; better
61 conversions should come earlier in the list. */
64 cr_identity,
65 cr_exact,
66 cr_promotion,
67 cr_std,
68 cr_pbool,
69 cr_user,
70 cr_ellipsis,
71 cr_bad
74 /* An implicit conversion sequence, in the sense of [over.best.ics].
75 The first conversion to be performed is at the end of the chain.
76 That conversion is always a cr_identity conversion. */
80 /* The kind of conversion represented by this step. */
81 conversion_kind kind;
82 /* The rank of this conversion. */
83 conversion_rank rank;
88 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
89 temporary should be created to hold the result of the
90 conversion. */
92 /* If KIND is ck_identity or ck_base_conv, true to indicate that the
93 copy constructor must be accessible, even though it is not being
94 used. */
96 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
97 from a pointer-to-derived to pointer-to-base is being performed. */
99 /* The type of the expression resulting from the conversion. */
100 tree type;
102 /* The next conversion in the chain. Since the conversions are
103 arranged from outermost to innermost, the NEXT conversion will
104 actually be performed before this conversion. This variant is
105 used only when KIND is neither ck_identity nor ck_ambig. */
107 /* The expression at the beginning of the conversion chain. This
108 variant is used only if KIND is ck_identity or ck_ambig. */
109 tree expr;
111 /* The function candidate corresponding to this conversion
112 sequence. This field is only used if KIND is ck_user. */
114 };
116 #define CONVERSION_RANK(NODE) \
117 ((NODE)->bad_p ? cr_bad \
118 : (NODE)->ellipsis_p ? cr_ellipsis \
119 : (NODE)->user_conv_p ? cr_user \
120 : (NODE)->rank)
131 #define convert_like(CONV, EXPR) \
132 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
135 #define convert_like_with_context(CONV, EXPR, FN, ARGNO) \
136 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
159 static void add_builtin_candidates
162 static void add_builtin_candidate
166 static void build_builtin_candidate
202 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
203 NAME can take many forms... */
205 bool
207 {
208 /* Just accept something we've already complained about. */
217 {
222 else
224 }
225 else
226 {
227 /* In the case of:
229 template <class T> struct S { ~S(); };
230 int i;
231 i.~S();
233 NAME will be a class template. */
236 }
241 }
243 /* We want the address of a function or method. We avoid creating a
244 pointer-to-member function. */
246 tree
248 {
251 /* We have to do these by hand to avoid real pointer to member
252 functions. */
254 {
256 {
260 }
262 }
263 else
267 }
269 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
270 POINTER_TYPE to those. Note, pointer to member function types
271 (TYPE_PTRMEMFUNC_P) must be handled by our callers. */
273 tree
275 {
278 tree tmp;
279 tree decl;
280 tree result_type;
281 tree fntype;
293 {
296 {
297 /* We invoke build_call directly for several library
298 functions. These may have been declared normally if
299 we're building libgcc, so we can't just check
300 DECL_ARTIFICIAL. */
305 }
306 }
307 else
310 /* We check both the decl and the type; a function may be known not to
311 throw without being declared throw(). */
325 /* Don't pass empty class objects by value. This is useful
326 for tags in STL, which are used to control overload resolution.
327 We don't need to handle other cases of copying empty classes. */
332 {
336 }
343 }
345 /* Build something of the form ptr->method (args)
346 or object.method (args). This can also build
347 calls to constructors, and find friends.
349 Member functions always take their class variable
350 as a pointer.
352 INSTANCE is a class instance.
354 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
356 PARMS help to figure out what that NAME really refers to.
358 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
359 down to the real instance type to use for access checking. We need this
360 information to get protected accesses correct.
362 FLAGS is the logical disjunction of zero or more LOOKUP_
363 flags. See cp-tree.h for more info.
365 If this is all OK, calls build_function_call with the resolved
366 member function.
368 This function must also handle being called to perform
369 initialization, promotion/coercion of arguments, and
370 instantiation of default parameters.
372 Note that NAME may refer to an instance variable name. If
373 `operator()()' is defined for the type of that field, then we return
374 that result. */
376 /* New overloading code. */
384 };
387 /* The FUNCTION_DECL that will be called if this candidate is
388 selected by overload resolution. */
389 tree fn;
390 /* The arguments to use when calling this function. */
391 tree args;
392 /* The implicit conversion sequences for each of the arguments to
393 FN. */
395 /* The number of implicit conversion sequences. */
397 /* If FN is a user-defined conversion, the standard conversion
398 sequence from the type returned by FN to the desired destination
399 type. */
402 /* If FN is a member function, the binfo indicating the path used to
403 qualify the name of FN at the call site. This path is used to
404 determine whether or not FN is accessible if it is selected by
405 overload resolution. The DECL_CONTEXT of FN will always be a
406 (possibly improper) base of this binfo. */
407 tree access_path;
408 /* If FN is a non-static member function, the binfo indicating the
409 subobject to which the `this' pointer should be converted if FN
410 is selected by overload resolution. The type pointed to the by
411 the `this' pointer must correspond to the most derived class
412 indicated by the CONVERSION_PATH. */
413 tree conversion_path;
414 tree template_decl;
417 };
419 /* Returns true iff T is a null pointer constant in the sense of
420 [conv.ptr]. */
422 bool
424 {
425 /* [conv.ptr]
427 A null pointer constant is an integral constant expression
428 (_expr.const_) rvalue of integer type that evaluates to zero. */
433 {
437 }
439 }
441 /* Returns nonzero if PARMLIST consists of only default parms and/or
442 ellipsis. */
444 bool
446 {
452 }
454 /* Allocate N bytes of memory from the conversion obstack. The memory
455 is zeroed before being returned. */
459 {
462 {
465 }
469 }
471 /* Dynamically allocate a conversion. */
475 {
480 }
482 #ifdef ENABLE_CHECKING
484 /* Make sure that all memory on the conversion obstack has been
485 freed. */
487 void
489 {
493 }
497 /* Dynamically allocate an array of N conversions. */
501 {
503 }
507 {
511 /* We can't use buildl1 here because CODE could be USER_CONV, which
512 takes two arguments. In that case, the caller is responsible for
513 filling in the second argument. */
519 {
535 }
541 }
543 /* Build a representation of the identity conversion from EXPR to
544 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
548 {
556 }
558 /* Converting from EXPR to TYPE was ambiguous in the sense that there
559 were multiple user-defined conversions to accomplish the job.
560 Build a conversion that indicates that ambiguity. */
564 {
572 }
574 tree
576 {
580 }
582 /* Returns the standard conversion path (see [conv]) from type FROM to type
583 TO, if any. For proper handling of null pointer constants, you must
584 also pass the expression EXPR to convert from. If C_CAST_P is true,
585 this conversion is coming from a C-style cast. */
590 {
597 {
600 }
606 {
611 }
618 {
622 }
624 {
628 }
630 {
632 {
633 tree bitfield_type;
637 }
639 }
641 /* Allow conversion between `__complex__' data types. */
643 {
644 /* The standard conversion sequence to convert FROM to TO is
645 the standard conversion sequence to perform componentwise
646 conversion. */
651 {
654 }
655 else
659 }
669 {
670 /* For backwards brain damage compatibility, allow interconversion of
671 pointers and integers with a pedwarn. */
674 }
676 {
677 /* For backwards brain damage compatibility, allow interconversion of
678 enums and integers with a pedwarn. */
681 }
684 {
685 tree to_pointee;
686 tree from_pointee;
691 ;
695 {
696 from = build_pointer_type
700 }
702 {
707 && (same_type_ignoring_top_level_qualifiers_p
710 {
714 }
717 }
720 /* [conv.ptr]
722 An rvalue of type "pointer to cv D," where D is a
723 class type, can be converted to an rvalue of type
724 "pointer to cv B," where B is a base class (clause
725 _class.derived_) of D. If B is an inaccessible
726 (clause _class.access_) or ambiguous
727 (_class.member.lookup_) base class of D, a program
728 that necessitates this conversion is ill-formed.
729 Therefore, we use DERIVED_FROM_P, and do not check
730 access or uniqueness. */
732 /* If FROM is not yet complete, then we must be parsing
733 the body of a class. We know what's derived from
734 what, but we can't actually perform a
735 derived-to-base conversion. For example, in:
737 struct D : public B {
738 static const int i = sizeof((B*)(D*)0);
739 };
741 the D*-to-B* conversion is a reinterpret_cast, not a
742 static_cast. */
744 {
745 from =
751 }
754 {
757 }
758 else
759 {
762 }
767 /* In a C-style cast, we ignore CV-qualification because we
768 are allowed to perform a static_cast followed by a
769 const_cast. */
774 /* converting from string constant to char *. */
777 {
780 }
781 else
785 }
787 {
807 }
809 {
810 /* [conv.bool]
812 An rvalue of arithmetic, enumeration, pointer, or pointer to
813 member type can be converted to an rvalue of type bool. */
818 {
826 }
829 }
830 /* We don't check for ENUMERAL_TYPE here because there are no standard
831 conversions to enum type. */
834 {
839 /* Give this a better rank if it's a promotion. */
843 }
850 {
854 /* The derived-to-base conversion indicates the initialization
855 of a parameter with base type from an object of a derived
856 type. A temporary object is created to hold the result of
857 the conversion. */
859 }
860 else
864 }
866 /* Returns nonzero if T1 is reference-related to T2. */
868 static bool
870 {
874 /* [dcl.init.ref]
876 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
877 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
878 of T2. */
882 }
884 /* Returns nonzero if T1 is reference-compatible with T2. */
886 static bool
888 {
889 /* [dcl.init.ref]
891 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
892 reference-related to T2 and cv1 is the same cv-qualification as,
893 or greater cv-qualification than, cv2. */
896 }
898 /* Determine whether or not the EXPR (of class type S) can be
899 converted to T as in [over.match.ref]. */
903 {
904 tree conversions;
905 tree arglist;
907 tree reference_type;
916 /* [over.match.ref]
918 Assuming that "cv1 T" is the underlying type of the reference
919 being initialized, and "cv S" is the type of the initializer
920 expression, with S a class type, the candidate functions are
921 selected as follows:
923 --The conversion functions of S and its base classes are
924 considered. Those that are not hidden within S and yield type
925 "reference to cv2 T2", where "cv1 T" is reference-compatible
926 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
928 The argument list has one argument, which is the initializer
929 expression. */
933 /* Conceptually, we should take the address of EXPR and put it in
934 the argument list. Unfortunately, however, that can result in
935 error messages, which we should not issue now because we are just
936 trying to find a conversion operator. Therefore, we use NULL,
937 cast to the appropriate type. */
944 {
948 {
954 /* If this is a template function, try to get an exact
955 match. */
957 {
960 NULL_TREE,
961 arglist,
962 reference_type,
965 LOOKUP_NORMAL,
966 DEDUCE_CONV);
969 {
970 /* Now, see if the conversion function really returns
971 an lvalue of the appropriate type. From the
972 point of view of unification, simply returning an
973 rvalue of the right type is good enough. */
978 {
981 }
982 }
983 }
989 LOOKUP_NORMAL);
992 {
994 /* Build a standard conversion sequence indicating the
995 binding from the reference type returned by the
996 function to the desired REFERENCE_TYPE. */
997 identity_conv
1000 NULL_TREE);
1001 cand->second_conv
1002 = (direct_reference_binding
1005 }
1006 }
1008 }
1011 /* If none of the conversion functions worked out, let our caller
1012 know. */
1020 /* Now that we know that this is the function we're going to use fix
1021 the dummy first argument. */
1026 /* Build a user-defined conversion sequence representing the
1027 conversion. */
1033 /* Merge it with the standard conversion sequence from the
1034 conversion function's return type to the desired type. */
1041 }
1043 /* A reference of the indicated TYPE is being bound directly to the
1044 expression represented by the implicit conversion sequence CONV.
1045 Return a conversion sequence for this binding. */
1049 {
1050 tree t;
1057 /* [over.ics.rank]
1059 When a parameter of reference type binds directly
1060 (_dcl.init.ref_) to an argument expression, the implicit
1061 conversion sequence is the identity conversion, unless the
1062 argument expression has a type that is a derived class of the
1063 parameter type, in which case the implicit conversion sequence is
1064 a derived-to-base Conversion.
1066 If the parameter binds directly to the result of applying a
1067 conversion function to the argument expression, the implicit
1068 conversion sequence is a user-defined conversion sequence
1069 (_over.ics.user_), with the second standard conversion sequence
1070 either an identity conversion or, if the conversion function
1071 returns an entity of a type that is a derived class of the
1072 parameter type, a derived-to-base conversion. */
1074 {
1075 /* Represent the derived-to-base conversion. */
1077 /* We will actually be binding to the base-class subobject in
1078 the derived class, so we mark this conversion appropriately.
1079 That way, convert_like knows not to generate a temporary. */
1081 }
1083 }
1085 /* Returns the conversion path from type FROM to reference type TO for
1086 purposes of reference binding. For lvalue binding, either pass a
1087 reference type to FROM or an lvalue expression to EXPR. If the
1088 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1089 the conversion returned. */
1093 {
1102 {
1107 }
1110 {
1111 /* Anything with reference type is an lvalue. */
1114 }
1118 /* Figure out whether or not the types are reference-related and
1119 reference compatible. We have do do this after stripping
1120 references from FROM. */
1125 {
1126 /* [dcl.init.ref]
1128 If the initializer expression
1130 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1131 is reference-compatible with "cv2 T2,"
1133 the reference is bound directly to the initializer expression
1134 lvalue. */
1139 /* For the purposes of overload resolution, we ignore the fact
1140 this expression is a bitfield or packed field. (In particular,
1141 [over.ics.ref] says specifically that a function with a
1142 non-const reference parameter is viable even if the
1143 argument is a bitfield.)
1145 However, when we actually call the function we must create
1146 a temporary to which to bind the reference. If the
1147 reference is volatile, or isn't const, then we cannot make
1148 a temporary, so we just issue an error when the conversion
1149 actually occurs. */
1153 }
1155 {
1156 /* [dcl.init.ref]
1158 If the initializer expression
1160 -- has a class type (i.e., T2 is a class type) can be
1161 implicitly converted to an lvalue of type "cv3 T3," where
1162 "cv1 T1" is reference-compatible with "cv3 T3". (this
1163 conversion is selected by enumerating the applicable
1164 conversion functions (_over.match.ref_) and choosing the
1165 best one through overload resolution. (_over.match_).
1167 the reference is bound to the lvalue result of the conversion
1168 in the second case. */
1172 }
1174 /* From this point on, we conceptually need temporaries, even if we
1175 elide them. Only the cases above are "direct bindings". */
1179 /* [over.ics.rank]
1181 When a parameter of reference type is not bound directly to an
1182 argument expression, the conversion sequence is the one required
1183 to convert the argument expression to the underlying type of the
1184 reference according to _over.best.ics_. Conceptually, this
1185 conversion sequence corresponds to copy-initializing a temporary
1186 of the underlying type with the argument expression. Any
1187 difference in top-level cv-qualification is subsumed by the
1188 initialization itself and does not constitute a conversion. */
1190 /* [dcl.init.ref]
1192 Otherwise, the reference shall be to a non-volatile const type. */
1196 /* [dcl.init.ref]
1198 If the initializer expression is an rvalue, with T2 a class type,
1199 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1200 is bound in one of the following ways:
1202 -- The reference is bound to the object represented by the rvalue
1203 or to a sub-object within that object.
1205 -- ...
1207 We use the first alternative. The implicit conversion sequence
1208 is supposed to be same as we would obtain by generating a
1209 temporary. Fortunately, if the types are reference compatible,
1210 then this is either an identity conversion or the derived-to-base
1211 conversion, just as for direct binding. */
1213 {
1219 }
1221 /* [dcl.init.ref]
1223 Otherwise, a temporary of type "cv1 T1" is created and
1224 initialized from the initializer expression using the rules for a
1225 non-reference copy initialization. If T1 is reference-related to
1226 T2, cv1 must be the same cv-qualification as, or greater
1227 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1232 flags);
1237 /* This reference binding, unlike those above, requires the
1238 creation of a temporary. */
1242 }
1244 /* Returns the implicit conversion sequence (see [over.ics]) from type
1245 FROM to type TO. The optional expression EXPR may affect the
1246 conversion. FLAGS are the usual overloading flags. Only
1247 LOOKUP_NO_CONVERSION is significant. If C_CAST_P is true, this
1248 conversion is coming from a C-style cast. */
1253 {
1262 else
1272 {
1275 cand = build_user_type_conversion_1
1280 /* We used to try to bind a reference to a temporary here, but that
1281 is now handled by the recursive call to this function at the end
1282 of reference_binding. */
1284 }
1287 }
1289 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1290 functions. */
1298 {
1313 }
1315 /* Create an overload candidate for the function or method FN called with
1316 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1317 to implicit_conversion.
1319 CTYPE, if non-NULL, is the type we want to pretend this function
1320 comes from for purposes of overload resolution. */
1327 {
1332 tree orig_arglist;
1335 /* At this point we should not see any functions which haven't been
1336 explicitly declared, except for friend functions which will have
1337 been found using argument dependent lookup. */
1340 /* The `this', `in_chrg' and VTT arguments to constructors are not
1341 considered in overload resolution. */
1343 {
1347 }
1348 else
1354 /* 13.3.2 - Viable functions [over.match.viable]
1355 First, to be a viable function, a candidate function shall have enough
1356 parameters to agree in number with the arguments in the list.
1358 We need to check this first; otherwise, checking the ICSes might cause
1359 us to produce an ill-formed template instantiation. */
1363 {
1367 }
1372 /* Make sure there are default args for the rest of the parms. */
1379 /* Second, for F to be a viable function, there shall exist for each
1380 argument an implicit conversion sequence that converts that argument
1381 to the corresponding parameter of F. */
1387 {
1400 {
1403 /* The type of the implicit object parameter ('this') for
1404 overload resolution is not always the same as for the
1405 function itself; conversion functions are considered to
1406 be members of the class being converted, and functions
1407 introduced by a using-declaration are considered to be
1408 members of the class that uses them.
1410 Since build_over_call ignores the ICS for the `this'
1411 parameter, we can just change the parm type. */
1413 {
1414 parmtype
1418 }
1422 }
1423 else
1424 {
1427 }
1434 {
1437 }
1445 }
1447 out:
1450 }
1452 /* Create an overload candidate for the conversion function FN which will
1453 be invoked for expression OBJ, producing a pointer-to-function which
1454 will in turn be called with the argument list ARGLIST, and add it to
1455 CANDIDATES. FLAGS is passed on to implicit_conversion.
1457 Actually, we don't really care about FN; we care about the type it
1458 converts to. There may be multiple conversion functions that will
1459 convert to that type, and we rely on build_user_type_conversion_1 to
1460 choose the best one; so when we create our candidate, we record the type
1461 instead of the function. */
1466 {
1483 /* Don't bother looking up the same type twice. */
1488 {
1495 flags);
1501 else
1502 {
1505 }
1520 }
1530 }
1532 static void
1536 {
1550 {
1557 {
1559 /* We need something for printing the candidate. */
1561 }
1565 }
1567 /* For COND_EXPR we rearranged the arguments; undo that now. */
1569 {
1576 else
1578 }
1584 viable);
1585 }
1587 static bool
1589 {
1591 }
1593 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1595 static bool
1597 {
1598 /* [over.built]
1600 In this section, the term promoted integral type is used to refer
1601 to those integral types which are preserved by integral promotion
1602 (including e.g. int and long but excluding e.g. char).
1603 Similarly, the term promoted arithmetic type refers to promoted
1604 integral types plus floating types. */
1608 }
1610 /* Create any builtin operator overload candidates for the operator in
1611 question given the converted operand types TYPE1 and TYPE2. The other
1612 args are passed through from add_builtin_candidates to
1613 build_builtin_candidate.
1615 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1616 If CODE is requires candidates operands of the same type of the kind
1617 of which TYPE1 and TYPE2 are, we add both candidates
1618 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1620 static void
1624 {
1626 {
1634 }
1637 {
1639 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1640 and VQ is either volatile or empty, there exist candidate operator
1641 functions of the form
1642 VQ T& operator++(VQ T&);
1643 T operator++(VQ T&, int);
1644 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1645 type other than bool, and VQ is either volatile or empty, there exist
1646 candidate operator functions of the form
1647 VQ T& operator--(VQ T&);
1648 T operator--(VQ T&, int);
1649 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1650 complete object type, and VQ is either volatile or empty, there exist
1651 candidate operator functions of the form
1652 T*VQ& operator++(T*VQ&);
1653 T*VQ& operator--(T*VQ&);
1654 T* operator++(T*VQ&, int);
1655 T* operator--(T*VQ&, int); */
1664 {
1667 }
1670 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1671 exist candidate operator functions of the form
1673 T& operator*(T*);
1675 8 For every function type T, there exist candidate operator functions of
1676 the form
1677 T& operator*(T*); */
1686 /* 9 For every type T, there exist candidate operator functions of the form
1687 T* operator+(T*);
1689 10For every promoted arithmetic type T, there exist candidate operator
1690 functions of the form
1691 T operator+(T);
1692 T operator-(T); */
1702 /* 11For every promoted integral type T, there exist candidate operator
1703 functions of the form
1704 T operator~(T); */
1711 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1712 is the same type as C2 or is a derived class of C2, T is a complete
1713 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1714 there exist candidate operator functions of the form
1715 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1716 where CV12 is the union of CV1 and CV2. */
1721 {
1729 }
1732 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1733 didate operator functions of the form
1734 LR operator*(L, R);
1735 LR operator/(L, R);
1736 LR operator+(L, R);
1737 LR operator-(L, R);
1738 bool operator<(L, R);
1739 bool operator>(L, R);
1740 bool operator<=(L, R);
1741 bool operator>=(L, R);
1742 bool operator==(L, R);
1743 bool operator!=(L, R);
1744 where LR is the result of the usual arithmetic conversions between
1745 types L and R.
1747 14For every pair of types T and I, where T is a cv-qualified or cv-
1748 unqualified complete object type and I is a promoted integral type,
1749 there exist candidate operator functions of the form
1750 T* operator+(T*, I);
1751 T& operator[](T*, I);
1752 T* operator-(T*, I);
1753 T* operator+(I, T*);
1754 T& operator[](I, T*);
1756 15For every T, where T is a pointer to complete object type, there exist
1757 candidate operator functions of the form112)
1758 ptrdiff_t operator-(T, T);
1760 16For every pointer or enumeration type T, there exist candidate operator
1761 functions of the form
1762 bool operator<(T, T);
1763 bool operator>(T, T);
1764 bool operator<=(T, T);
1765 bool operator>=(T, T);
1766 bool operator==(T, T);
1767 bool operator!=(T, T);
1769 17For every pointer to member type T, there exist candidate operator
1770 functions of the form
1771 bool operator==(T, T);
1772 bool operator!=(T, T); */
1778 {
1781 }
1794 {
1797 }
1799 {
1802 }
1803 /* Fall through. */
1820 {
1823 }
1827 {
1830 }
1838 {
1841 }
1843 {
1846 }
1849 /* 18For every pair of promoted integral types L and R, there exist candi-
1850 date operator functions of the form
1851 LR operator%(L, R);
1852 LR operator&(L, R);
1853 LR operator^(L, R);
1854 LR operator|(L, R);
1855 L operator<<(L, R);
1856 L operator>>(L, R);
1857 where LR is the result of the usual arithmetic conversions between
1858 types L and R. */
1870 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1871 type, VQ is either volatile or empty, and R is a promoted arithmetic
1872 type, there exist candidate operator functions of the form
1873 VQ L& operator=(VQ L&, R);
1874 VQ L& operator*=(VQ L&, R);
1875 VQ L& operator/=(VQ L&, R);
1876 VQ L& operator+=(VQ L&, R);
1877 VQ L& operator-=(VQ L&, R);
1879 20For every pair T, VQ), where T is any type and VQ is either volatile
1880 or empty, there exist candidate operator functions of the form
1881 T*VQ& operator=(T*VQ&, T*);
1883 21For every pair T, VQ), where T is a pointer to member type and VQ is
1884 either volatile or empty, there exist candidate operator functions of
1885 the form
1886 VQ T& operator=(VQ T&, T);
1888 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1889 unqualified complete object type, VQ is either volatile or empty, and
1890 I is a promoted integral type, there exist candidate operator func-
1891 tions of the form
1892 T*VQ& operator+=(T*VQ&, I);
1893 T*VQ& operator-=(T*VQ&, I);
1895 23For every triple L, VQ, R), where L is an integral or enumeration
1896 type, VQ is either volatile or empty, and R is a promoted integral
1897 type, there exist candidate operator functions of the form
1899 VQ L& operator%=(VQ L&, R);
1900 VQ L& operator<<=(VQ L&, R);
1901 VQ L& operator>>=(VQ L&, R);
1902 VQ L& operator&=(VQ L&, R);
1903 VQ L& operator^=(VQ L&, R);
1904 VQ L& operator|=(VQ L&, R); */
1908 {
1912 {
1915 }
1941 {
1944 }
1949 }
1954 /* [over.built]
1956 For every pair of promoted arithmetic types L and R, there
1957 exist candidate operator functions of the form
1959 LR operator?(bool, L, R);
1961 where LR is the result of the usual arithmetic conversions
1962 between types L and R.
1964 For every type T, where T is a pointer or pointer-to-member
1965 type, there exist candidate operator functions of the form T
1966 operator?(bool, T, T); */
1970 /* That's OK. */
1973 /* Otherwise, the types should be pointers. */
1978 /* We don't check that the two types are the same; the logic
1979 below will actually create two candidates; one in which both
1980 parameter types are TYPE1, and one in which both parameter
1981 types are TYPE2. */
1986 }
1988 /* If we're dealing with two pointer types or two enumeral types,
1989 we need candidates for both of them. */
1998 {
1999 build_builtin_candidate
2001 build_builtin_candidate
2004 }
2006 build_builtin_candidate
2008 }
2010 tree
2012 {
2018 }
2020 /* There are three conditions of builtin candidates:
2022 1) bool-taking candidates. These are the same regardless of the input.
2023 2) pointer-pair taking candidates. These are generated for each type
2024 one of the input types converts to.
2025 3) arithmetic candidates. According to the standard, we should generate
2026 all of these, but I'm trying not to...
2028 Here we generate a superset of the possible candidates for this particular
2029 case. That is a subset of the full set the standard defines, plus some
2030 other cases which the standard disallows. add_builtin_candidate will
2031 filter out the invalid set. */
2033 static void
2037 {
2041 /* TYPES[i] is the set of possible builtin-operator parameter types
2042 we will consider for the Ith argument. These are represented as
2043 a TREE_LIST; the TREE_VALUE of each node is the potential
2044 parameter type. */
2048 {
2051 else
2053 }
2056 {
2057 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2058 and VQ is either volatile or empty, there exist candidate operator
2059 functions of the form
2060 VQ T& operator++(VQ T&); */
2070 /* 24There also exist candidate operator functions of the form
2071 bool operator!(bool);
2072 bool operator&&(bool, bool);
2073 bool operator||(bool, bool); */
2076 build_builtin_candidate
2083 build_builtin_candidate
2101 /* Fall through. */
2105 }
2110 {
2112 ;
2114 {
2115 tree convs;
2123 {
2130 }
2136 {
2149 {
2155 }
2159 }
2160 }
2161 else
2162 {
2168 {
2174 }
2176 }
2177 }
2179 /* Run through the possible parameter types of both arguments,
2180 creating candidates with those parameter types. */
2182 {
2185 add_builtin_candidate
2188 else
2189 add_builtin_candidate
2192 }
2193 }
2196 /* If TMPL can be successfully instantiated as indicated by
2197 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2199 TMPL is the template. EXPLICIT_TARGS are any explicit template
2200 arguments. ARGLIST is the arguments provided at the call-site.
2201 The RETURN_TYPE is the desired type for conversion operators. If
2202 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2203 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2204 add_conv_candidate. */
2211 unification_kind_t strict)
2212 {
2218 tree fn;
2220 /* We don't do deduction on the in-charge parameter, the VTT
2221 parameter or 'this'. */
2231 args_without_in_chrg,
2241 /* In [class.copy]:
2243 A member function template is never instantiated to perform the
2244 copy of a class object to an object of its class type.
2246 It's a little unclear what this means; the standard explicitly
2247 does allow a template to be used to copy a class. For example,
2248 in:
2250 struct A {
2251 A(A&);
2252 template <class T> A(const T&);
2253 };
2254 const A f ();
2255 void g () { A a (f ()); }
2257 the member template will be used to make the copy. The section
2258 quoted above appears in the paragraph that forbids constructors
2259 whose only parameter is (a possibly cv-qualified variant of) the
2260 class type, and a logical interpretation is that the intent was
2261 to forbid the instantiation of member templates which would then
2262 have that form. */
2264 {
2267 ctype))
2269 }
2272 /* Aha, this is a conversion function. */
2275 else
2280 /* This situation can occur if a member template of a template
2281 class is specialized. Then, instantiate_template might return
2282 an instantiation of the specialization, in which case the
2283 DECL_TI_TEMPLATE field will point at the original
2284 specialization. For example:
2286 template <class T> struct S { template <class U> void f(U);
2287 template <> void f(int) {}; };
2288 S<double> sd;
2289 sd.f(3);
2291 Here, TMPL will be template <class U> S<double>::f(U).
2292 And, instantiate template will give us the specialization
2293 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2294 for this will point at template <class T> template <> S<T>::f(int),
2295 so that we can find the definition. For the purposes of
2296 overload resolution, however, we want the original TMPL. */
2298 else
2302 }
2309 unification_kind_t strict)
2310 {
2311 return
2316 }
2323 {
2324 return
2328 }
2330 /* The CANDS are the set of candidates that were considered for
2331 overload resolution. Return the set of viable candidates. If none
2332 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2333 is true if a candidate should be considered viable only if it is
2334 strictly viable. */
2340 {
2351 {
2354 {
2360 }
2361 else
2363 }
2366 }
2368 static bool
2370 {
2375 }
2377 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2378 words, it is about to become the "this" pointer for a member
2379 function call. Take the address of the object. */
2381 static tree
2383 {
2384 /* In a template, we are only concerned about the type of the
2385 expression, so we can take a shortcut. */
2390 }
2392 /* Returns true iff functions are equivalent. Equivalent functions are
2393 not '==' only if one is a function-local extern function or if
2394 both are extern "C". */
2398 {
2403 }
2405 /* Print information about one overload candidate CANDIDATE. MSGSTR
2406 is the text to print before the candidate itself.
2408 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2409 to have been run through gettext by the caller. This wart makes
2410 life simpler in print_z_candidates and for the translators. */
2412 static void
2414 {
2416 {
2426 else
2429 }
2434 else
2436 }
2438 static void
2440 {
2445 /* There may be duplicates in the set of candidates. We put off
2446 checking this condition as long as possible, since we have no way
2447 to eliminate duplicates from a set of functions in less than n^2
2448 time. Now we are about to emit an error message, so it is more
2449 permissible to go slowly. */
2451 {
2453 /* Skip builtin candidates and conversion functions. */
2458 {
2462 else
2464 }
2465 }
2473 {
2474 /* Indent successive candidates by the width of the translation
2475 of the above string. */
2482 do
2483 {
2486 }
2488 }
2489 }
2491 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2492 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2493 the result of the conversion function to convert it to the final
2494 desired type. Merge the two sequences into a single sequence,
2495 and return the merged sequence. */
2499 {
2504 /* Find the end of the second conversion sequence. */
2509 /* Replace the identity conversion with the user conversion
2510 sequence. */
2513 /* The entire sequence is a user-conversion sequence. */
2517 }
2519 /* Returns the best overload candidate to perform the requested
2520 conversion. This function is used for three the overloading situations
2521 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2522 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2523 per [dcl.init.ref], so we ignore temporary bindings. */
2527 {
2536 /* We represent conversion within a hierarchy using RVALUE_CONV and
2537 BASE_CONV, as specified by [over.best.ics]; these become plain
2538 constructor calls, as specified in [dcl.init]. */
2552 {
2553 tree t;
2559 /* We should never try to call the abstract or base constructor
2560 from here. */
2564 }
2566 {
2576 flags,
2577 DEDUCE_CALL);
2578 else
2582 flags);
2586 }
2592 {
2593 tree fns;
2597 /* If we are called to convert to a reference type, we are trying to
2598 find an lvalue binding, so don't even consider temporaries. If
2599 we don't find an lvalue binding, the caller will try again to
2600 look for a temporary binding. */
2605 {
2608 /* [over.match.funcs] For conversion functions, the function
2609 is considered to be a member of the class of the implicit
2610 object argument for the purpose of defining the type of
2611 the implicit object parameter.
2613 So we pass fromtype as CTYPE to add_*_candidate. */
2617 NULL_TREE,
2620 conversion_path,
2621 flags,
2622 DEDUCE_CONV);
2623 else
2625 args,
2627 conversion_path,
2628 flags);
2631 {
2632 conversion *ics
2644 }
2645 }
2646 }
2654 {
2656 {
2660 }
2667 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2668 ambiguous conversion is no worse than another user-defined
2669 conversion. */
2672 }
2674 /* Build the user conversion sequence. */
2675 conv = build_conv
2682 /* Combine it with the second conversion sequence. */
2690 }
2692 tree
2694 {
2699 {
2704 }
2706 }
2708 /* Do any initial processing on the arguments to a function call. */
2710 static tree
2712 {
2713 tree t;
2715 {
2721 {
2724 }
2727 }
2729 }
2731 /* Perform overload resolution on FN, which is called with the ARGS.
2733 Return the candidate function selected by overload resolution, or
2734 NULL if the event that overload resolution failed. In the case
2735 that overload resolution fails, *CANDIDATES will be the set of
2736 candidates considered, and ANY_VIABLE_P will be set to true or
2737 false to indicate whether or not any of the candidates were
2738 viable.
2740 The ARGS should already have gone through RESOLVE_ARGS before this
2741 function is called. */
2745 tree args,
2748 {
2756 /* Check FN and ARGS. */
2764 {
2768 }
2770 /* Add the various candidate functions. */
2774 LOOKUP_NORMAL,
2775 candidates);
2783 }
2785 /* Return an expression for a call to FN (a namespace-scope function,
2786 or a static member function) with the ARGS. */
2788 tree
2790 {
2794 tree result;
2800 /* If this function was found without using argument dependent
2801 lookup, then we want to ignore any undeclared friend
2802 functions. */
2804 {
2809 {
2813 }
2814 }
2816 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2822 {
2830 else
2836 }
2837 else
2840 /* Free all the conversions we allocated. */
2844 }
2846 /* Build a call to a global operator new. FNNAME is the name of the
2847 operator (either "operator new" or "operator new[]") and ARGS are
2848 the arguments provided. *SIZE points to the total number of bytes
2849 required by the allocation, and is updated if that is changed here.
2850 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2851 function determines that no cookie should be used, after all,
2852 *COOKIE_SIZE is set to NULL_TREE. If FN is non-NULL, it will be
2853 set, upon return, to the allocation function called. */
2855 tree
2859 {
2860 tree fns;
2872 /* Based on:
2874 [expr.new]
2876 If this lookup fails to find the name, or if the allocated type
2877 is not a class type, the allocation function's name is looked
2878 up in the global scope.
2880 we disregard block-scope declarations of "operator new". */
2883 /* Figure out what function is being called. */
2886 /* If no suitable function could be found, issue an error message
2887 and give up. */
2889 {
2893 else
2899 }
2901 /* If a cookie is required, add some extra space. Whether
2902 or not a cookie is required cannot be determined until
2903 after we know which function was called. */
2905 {
2908 {
2910 /* In G++ 3.2, the check was implemented incorrectly; it
2911 looked at the placement expression, rather than the
2912 type of the function. */
2915 ptr_type_node))
2917 }
2918 else
2919 {
2920 tree arg_types;
2923 /* Skip the size_t parameter. */
2925 /* Check the remaining parameters (if any). */
2929 ptr_type_node))
2931 }
2932 /* If we need a cookie, adjust the number of bytes allocated. */
2934 {
2935 /* Update the total size. */
2937 /* Update the argument list to reflect the adjusted size. */
2939 }
2940 else
2942 }
2944 /* Tell our caller which function we decided to call. */
2948 /* Build the CALL_EXPR. */
2950 }
2952 static tree
2954 {
2963 {
2964 /* It's no good looking for an overloaded operator() on a
2965 pointer-to-member-function. */
2966 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
2968 }
2971 {
2975 }
2976 else
2984 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2988 {
2993 {
3001 else
3002 add_function_candidate
3005 }
3006 }
3011 {
3023 {
3026 add_template_conv_candidate
3030 else
3034 }
3035 }
3039 {
3043 }
3044 else
3045 {
3048 {
3052 }
3053 /* Since cand->fn will be a type, not a function, for a conversion
3054 function, we must be careful not to unconditionally look at
3055 DECL_NAME here. */
3059 else
3060 {
3064 }
3065 }
3067 /* Free all the conversions we allocated. */
3071 }
3073 static void
3076 {
3081 else
3085 {
3109 else
3113 }
3114 }
3116 /* Return the implicit conversion sequence that could be used to
3117 convert E1 to E2 in [expr.cond]. */
3121 {
3127 /* [expr.cond]
3129 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3130 implicitly converted (clause _conv_) to the type "reference to
3131 T2", subject to the constraint that in the conversion the
3132 reference must bind directly (_dcl.init.ref_) to E1. */
3134 {
3136 t1,
3137 e1,
3139 LOOKUP_NO_TEMP_BIND);
3142 }
3144 /* [expr.cond]
3146 If E1 and E2 have class type, and the underlying class types are
3147 the same or one is a base class of the other: E1 can be converted
3148 to match E2 if the class of T2 is the same type as, or a base
3149 class of, the class of T1, and the cv-qualification of T2 is the
3150 same cv-qualification as, or a greater cv-qualification than, the
3151 cv-qualification of T1. If the conversion is applied, E1 is
3152 changed to an rvalue of type T2 that still refers to the original
3153 source class object (or the appropriate subobject thereof). */
3156 {
3158 {
3163 else
3166 }
3167 else
3169 }
3170 else
3171 /* [expr.cond]
3173 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3174 converted to the type that expression E2 would have if E2 were
3175 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3177 LOOKUP_NORMAL);
3178 }
3180 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3181 arguments to the conditional expression. */
3183 tree
3185 {
3186 tree arg2_type;
3187 tree arg3_type;
3195 /* As a G++ extension, the second argument to the conditional can be
3196 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3197 c'.) If the second operand is omitted, make sure it is
3198 calculated only once. */
3200 {
3204 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3207 else
3209 }
3211 /* [expr.cond]
3213 The first expr ession is implicitly converted to bool (clause
3214 _conv_). */
3217 /* If something has already gone wrong, just pass that fact up the
3218 tree. */
3224 /* [expr.cond]
3226 If either the second or the third operand has type (possibly
3227 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3228 array-to-pointer (_conv.array_), and function-to-pointer
3229 (_conv.func_) standard conversions are performed on the second
3230 and third operands. */
3238 {
3239 /* Do the conversions. We don't these for `void' type arguments
3240 since it can't have any effect and since decay_conversion
3241 does not handle that case gracefully. */
3249 /* [expr.cond]
3251 One of the following shall hold:
3253 --The second or the third operand (but not both) is a
3254 throw-expression (_except.throw_); the result is of the
3255 type of the other and is an rvalue.
3257 --Both the second and the third operands have type void; the
3258 result is of type void and is an rvalue.
3260 We must avoid calling force_rvalue for expressions of type
3261 "void" because it will complain that their value is being
3262 used. */
3265 {
3270 }
3273 {
3278 }
3281 else
3282 {
3286 }
3290 }
3291 /* [expr.cond]
3293 Otherwise, if the second and third operand have different types,
3294 and either has (possibly cv-qualified) class type, an attempt is
3295 made to convert each of those operands to the type of the other. */
3298 {
3302 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3308 /* [expr.cond]
3310 If both can be converted, or one can be converted but the
3311 conversion is ambiguous, the program is ill-formed. If
3312 neither can be converted, the operands are left unchanged and
3313 further checking is performed as described below. If exactly
3314 one conversion is possible, that conversion is applied to the
3315 chosen operand and the converted operand is used in place of
3316 the original operand for the remainder of this section. */
3321 {
3325 }
3327 {
3331 /* Even if CONV2 is a valid conversion, the result of the
3332 conversion may be invalid. For example, if ARG3 has type
3333 "volatile X", and X does not have a copy constructor
3334 accepting a "volatile X&", then even if ARG2 can be
3335 converted to X, the conversion will fail. */
3338 }
3340 {
3346 }
3348 /* Free all the conversions we allocated. */
3354 /* If, after the conversion, both operands have class type,
3355 treat the cv-qualification of both operands as if it were the
3356 union of the cv-qualification of the operands.
3358 The standard is not clear about what to do in this
3359 circumstance. For example, if the first operand has type
3360 "const X" and the second operand has a user-defined
3361 conversion to "volatile X", what is the type of the second
3362 operand after this step? Making it be "const X" (matching
3363 the first operand) seems wrong, as that discards the
3364 qualification without actually performing a copy. Leaving it
3365 as "volatile X" seems wrong as that will result in the
3366 conditional expression failing altogether, even though,
3367 according to this step, the one operand could be converted to
3368 the type of the other. */
3376 }
3378 /* [expr.cond]
3380 If the second and third operands are lvalues and have the same
3381 type, the result is of that type and is an lvalue. */
3385 {
3388 }
3390 /* [expr.cond]
3392 Otherwise, the result is an rvalue. If the second and third
3393 operand do not have the same type, and either has (possibly
3394 cv-qualified) class type, overload resolution is used to
3395 determine the conversions (if any) to be applied to the operands
3396 (_over.match.oper_, _over.built_). */
3400 {
3405 /* Rearrange the arguments so that add_builtin_candidate only has
3406 to know about two args. In build_builtin_candidates, the
3407 arguments are unscrambled. */
3412 COND_EXPR,
3413 NOP_EXPR,
3415 args,
3416 LOOKUP_NORMAL);
3418 /* [expr.cond]
3420 If the overload resolution fails, the program is
3421 ill-formed. */
3424 {
3428 }
3431 {
3435 }
3437 /* [expr.cond]
3439 Otherwise, the conversions thus determined are applied, and
3440 the converted operands are used in place of the original
3441 operands for the remainder of this section. */
3448 }
3450 /* [expr.cond]
3452 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3453 and function-to-pointer (_conv.func_) standard conversions are
3454 performed on the second and third operands.
3456 We need to force the lvalue-to-rvalue conversion here for class types,
3457 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3458 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3459 regions. */
3472 /* [expr.cond]
3474 After those conversions, one of the following shall hold:
3476 --The second and third operands have the same type; the result is of
3477 that type. */
3480 /* [expr.cond]
3482 --The second and third operands have arithmetic or enumeration
3483 type; the usual arithmetic conversions are performed to bring
3484 them to a common type, and the result is of that type. */
3489 {
3490 /* In this case, there is always a common type. */
3492 arg3_type);
3507 }
3508 /* [expr.cond]
3510 --The second and third operands have pointer type, or one has
3511 pointer type and the other is a null pointer constant; pointer
3512 conversions (_conv.ptr_) and qualification conversions
3513 (_conv.qual_) are performed to bring them to their composite
3514 pointer type (_expr.rel_). The result is of the composite
3515 pointer type.
3517 --The second and third operands have pointer to member type, or
3518 one has pointer to member type and the other is a null pointer
3519 constant; pointer to member conversions (_conv.mem_) and
3520 qualification conversions (_conv.qual_) are performed to bring
3521 them to a common type, whose cv-qualification shall match the
3522 cv-qualification of either the second or the third operand.
3523 The result is of the common type. */
3531 {
3538 }
3541 {
3545 }
3547 valid_operands:
3550 /* We can't use result_type below, as fold might have returned a
3551 throw_expr. */
3554 {
3555 /* Expand both sides into the same slot, hopefully the target of
3556 the ?: expression. We used to check for TARGET_EXPRs here,
3557 but now we sometimes wrap them in NOP_EXPRs so the test would
3558 fail. */
3561 /* If this expression is an rvalue, but might be mistaken for an
3562 lvalue, we must add a NON_LVALUE_EXPR. */
3564 }
3567 }
3569 /* OPERAND is an operand to an expression. Perform necessary steps
3570 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3571 returned. */
3573 static tree
3575 {
3577 {
3580 /* Make sure the template type is instantiated now. */
3582 }
3585 }
3587 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3588 OVERLOAD) to the CANDIDATES, returning an updated list of
3589 CANDIDATES. The ARGS are the arguments provided to the call,
3590 without any implicit object parameter. The EXPLICIT_TARGS are
3591 explicit template arguments provided. TEMPLATE_ONLY is true if
3592 only template functions should be considered. CONVERSION_PATH,
3593 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3595 static void
3601 {
3602 tree ctype;
3603 tree non_static_args;
3606 /* Delay creating the implicit this parameter until it is needed. */
3610 {
3611 tree fn;
3612 tree fn_args;
3615 /* Figure out which set of arguments to use. */
3617 {
3618 /* If this function is a non-static member, prepend the implicit
3619 object parameter. */
3625 }
3626 else
3627 /* Otherwise, just use the list of arguments provided. */
3632 fn,
3633 ctype,
3634 explicit_targs,
3635 fn_args,
3636 NULL_TREE,
3637 access_path,
3638 conversion_path,
3639 flags,
3640 DEDUCE_CALL);
3643 fn,
3644 ctype,
3645 fn_args,
3646 access_path,
3647 conversion_path,
3648 flags);
3650 }
3651 }
3653 tree
3656 {
3674 {
3678 }
3679 else
3685 {
3690 /* Use build_op_new_call and build_op_delete_call instead. */
3698 }
3704 {
3711 }
3726 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3729 /* Add namespace-scope operators to the list of functions to
3730 consider. */
3734 /* Add class-member operators to the candidate set. */
3736 {
3737 tree fns;
3741 {
3744 }
3751 }
3753 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3754 to know about two args; a builtin candidate will always have a first
3755 parameter of type bool. We'll handle that in
3756 build_builtin_candidate. */
3758 {
3762 }
3763 else
3764 {
3768 }
3773 {
3776 /* For these, the built-in candidates set is empty
3777 [over.match.oper]/3. We don't want non-strict matches
3778 because exact matches are always possible with built-in
3779 operators. The built-in candidate set for COMPONENT_REF
3780 would be empty too, but since there are no such built-in
3781 operators, we accept non-strict matches for them. */
3788 }
3792 {
3794 {
3797 /* Look for an `operator++ (int)'. If they didn't have
3798 one, then we fall back to the old way of doing things. */
3802 fnname,
3806 else
3809 overloaded_p);
3812 /* The caller will deal with these. */
3822 {
3825 }
3828 }
3829 }
3830 else
3831 {
3834 {
3836 {
3839 }
3841 }
3843 {
3848 }
3849 else
3850 {
3851 /* Give any warnings we noticed during overload resolution. */
3853 {
3857 }
3859 /* Check for comparison of different enum types. */
3861 {
3872 {
3875 }
3879 }
3881 /* We need to strip any leading REF_BIND so that bitfields
3882 don't cause errors. This should not remove any important
3883 conversions, because builtins don't apply to class
3884 objects directly. */
3890 {
3895 }
3897 {
3902 }
3903 }
3904 }
3906 user_defined_result_ready:
3908 /* Free all the conversions we allocated. */
3914 builtin:
3916 {
3966 /* The caller will deal with these. */
3974 }
3976 }
3978 /* Build a call to operator delete. This has to be handled very specially,
3979 because the restrictions on what signatures match are different from all
3980 other call instances. For a normal delete, only a delete taking (void *)
3981 or (void *, size_t) is accepted. For a placement delete, only an exact
3982 match with the placement new is accepted.
3984 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3985 ADDR is the pointer to be deleted.
3986 SIZE is the size of the memory block to be deleted.
3987 GLOBAL_P is true if the delete-expression should not consider
3988 class-specific delete operators.
3989 PLACEMENT is the corresponding placement new call, or NULL_TREE.
3990 If PLACEMENT is non-NULL, then ALLOC_FN is the allocation function
3991 called to perform the placement new. */
3993 tree
3996 tree alloc_fn)
3997 {
4012 /* In [class.free]
4014 If the result of the lookup is ambiguous or inaccessible, or if
4015 the lookup selects a placement deallocation function, the
4016 program is ill-formed.
4018 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4019 {
4023 }
4024 else
4031 {
4032 /* Get the parameter types for the allocation function that is
4033 being called. */
4036 /* Also the second argument. */
4038 }
4039 else
4040 {
4041 /* First try it without the size argument. */
4044 }
4046 /* Strip const and volatile from addr. */
4049 /* We make two tries at finding a matching `operator delete'. On
4050 the first pass, we look for a one-operator (or placement)
4051 operator delete. If we're not doing placement delete, then on
4052 the second pass we look for a two-argument delete. */
4054 {
4055 /* Go through the `operator delete' functions looking for one
4056 with a matching type. */
4058 fn;
4060 {
4061 tree t;
4063 /* The first argument must be "void *". */
4068 /* On the first pass, check the rest of the arguments. */
4070 {
4073 {
4078 }
4081 }
4082 /* On the second pass, the second argument must be
4083 "size_t". */
4088 }
4090 /* If we found a match, we're done. */
4093 }
4095 /* If we have a matching function, call it. */
4097 {
4098 /* Make sure we have the actual function, and not an
4099 OVERLOAD. */
4102 /* If the FN is a member function, make sure that it is
4103 accessible. */
4109 else
4114 {
4115 /* The placement args might not be suitable for overload
4116 resolution at this point, so build the call directly. */
4119 }
4120 else
4122 }
4124 /* If we are doing placement delete we do nothing if we don't find a
4125 matching op delete. */
4132 }
4134 /* If the current scope isn't allowed to access DECL along
4135 BASETYPE_PATH, give an error. The most derived class in
4136 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4137 the declaration to use in the error diagnostic. */
4139 bool
4141 {
4145 {
4150 else
4154 }
4157 }
4159 /* Check that a callable constructor to initialize a temporary of
4160 TYPE from an EXPR exists. */
4162 static void
4164 {
4166 complete_ctor_identifier,
4168 type,
4169 LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING
4170 | LOOKUP_NO_CONVERSION
4172 }
4174 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4175 bitwise or of LOOKUP_* values. If any errors are warnings are
4176 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4177 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4178 to NULL. */
4180 static tree
4183 {
4188 complete_ctor_identifier,
4195 else
4198 }
4201 /* Perform the conversions in CONVS on the expression EXPR. FN and
4202 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4203 indicates the `this' argument of a method. INNER is nonzero when
4204 being called to continue a conversion chain. It is negative when a
4205 reference binding will be applied, positive otherwise. If
4206 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4207 conversions will be emitted if appropriate. If C_CAST_P is true,
4208 this conversion is coming from a C-style cast; in that case,
4209 conversions to inaccessible bases are permitted. */
4211 static tree
4215 {
4217 diagnostic_fn_t diagnostic_fn;
4223 {
4226 {
4228 {
4233 }
4240 }
4245 }
4248 {
4251 /* Issue warnings about peculiar, but valid, uses of NULL. */
4253 {
4257 else
4259 }
4261 /* Warn about assigning a floating-point type to an integer type. */
4264 {
4268 else
4270 }
4271 }
4274 {
4276 {
4279 tree args;
4282 {
4287 /* We should never try to call the abstract or base constructor
4288 from here. */
4292 }
4293 else
4297 /* If this is a constructor or a function returning an aggr type,
4298 we need to build up a TARGET_EXPR. */
4302 /* The result of the call is then used to direct-initialize the object
4303 that is the destination of the copy-initialization. [dcl.init]
4305 Note that this step is not reflected in the conversion sequence;
4306 it affects the semantics when we actually perform the
4307 conversion, but is not considered during overload resolution.
4309 If the target is a class, that means call a ctor. */
4312 {
4313 expr = (build_temp
4315 /* Core issue 84, now a DR, says that we don't
4316 allow UDCs for these args (which deliberately
4317 breaks copy-init of an auto_ptr<Base> from an
4318 auto_ptr<Derived>). */
4323 {
4325 diagnostic_fn
4328 else
4329 diagnostic_fn
4331 }
4333 }
4335 }
4339 /* Convert a constant to its underlying value, unless we are
4340 about to bind it to a reference, in which case we need to
4341 leave it as an lvalue. */
4348 /* Call build_user_type_conversion again for the error. */
4349 return build_user_type_conversion
4354 };
4359 c_cast_p);
4364 {
4369 /* Else fall through. */
4372 {
4373 /* We are going to bind a reference directly to a base-class
4374 subobject of EXPR. */
4377 /* Build an expression for `*((base*) &expr)'. */
4383 }
4385 /* Copy-initialization where the cv-unqualified version of the source
4386 type is the same class as, or a derived class of, the class of the
4387 destination [is treated as direct-initialization]. [dcl.init] */
4395 {
4398 /* If necessary, create a temporary. */
4400 {
4405 {
4406 /* If the reference is volatile or non-const, we
4407 cannot create a temporary. */
4414 else
4417 }
4418 /* If the source is a packed field, and we must use a copy
4419 constructor, then building the target expr will require
4420 binding the field to the reference parameter to the
4421 copy constructor, and we'll end up with an infinite
4422 loop. If we can use a bitwise copy, then we'll be
4423 OK. */
4427 {
4431 }
4433 }
4435 /* Take the address of the thing to which we will bind the
4436 reference. */
4441 /* Convert it to a pointer to the type referred to by the
4442 reference. This will adjust the pointer if a derived to
4443 base conversion is being performed. */
4445 expr);
4446 /* Convert the pointer to the desired reference type. */
4448 }
4454 /* Warn about deprecated conversion if appropriate. */
4466 c_cast_p);
4470 }
4474 else
4478 }
4480 /* Build a call to __builtin_trap. */
4482 static tree
4484 {
4490 }
4492 /* ARG is being passed to a varargs function. Perform any conversions
4493 required. Return the converted value. */
4495 tree
4497 {
4498 /* [expr.call]
4500 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4501 standard conversions are performed. */
4503 /* [expr.call]
4505 If the argument has integral or enumeration type that is subject
4506 to the integral promotions (_conv.prom_), or a floating point
4507 type that is subject to the floating point promotion
4508 (_conv.fpprom_), the value of the argument is converted to the
4509 promoted type before the call. */
4521 {
4522 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4523 here and do a bitwise copy, but now cp_expr_size will abort if we
4524 try to do that.
4525 If the call appears in the context of a sizeof expression,
4526 there is no need to emit a warning, since the expression won't be
4527 evaluated. We keep the builtin_trap just as a safety check. */
4533 integer_zero_node);
4534 }
4537 }
4539 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4541 tree
4543 {
4553 {
4554 /* Remove reference types so we don't ICE later on. */
4556 /* Undefined behavior [expr.call] 5.2.2/7. */
4564 }
4567 }
4569 /* TYPE has been given to va_arg. Apply the default conversions which
4570 would have happened when passed via ellipsis. Return the promoted
4571 type, or the passed type if there is no change. */
4573 tree
4575 {
4576 tree promote;
4578 /* Perform the array-to-pointer and function-to-pointer
4579 conversions. */
4587 }
4589 /* ARG is a default argument expression being passed to a parameter of
4590 the indicated TYPE, which is a parameter to FN. Do any required
4591 conversions. Return the converted value. */
4593 tree
4595 {
4596 /* If the ARG is an unparsed default argument expression, the
4597 conversion cannot be performed. */
4599 {
4604 }
4612 {
4616 }
4617 else
4618 {
4619 /* This could get clobbered by the following call. */
4626 }
4629 }
4631 /* Returns the type which will really be used for passing an argument of
4632 type TYPE. */
4634 tree
4636 {
4637 /* Pass classes with copy ctors by invisible reference. */
4639 {
4641 /* There are no other pointers to this temporary. */
4643 }
4652 }
4654 /* Actually perform the appropriate conversion. */
4656 tree
4658 {
4660 ;
4661 /* Pass classes with copy ctors by invisible reference. */
4671 {
4680 }
4682 }
4684 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4685 which no conversions at all should be done. This is true for some
4686 builtins which don't act like normal functions. */
4688 static bool
4690 {
4693 {
4702 }
4705 }
4707 /* Subroutine of the various build_*_call functions. Overload resolution
4708 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4709 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4710 bitmask of various LOOKUP_* flags which apply to the call itself. */
4712 static tree
4714 {
4725 /* In a template, there is no need to perform all of the work that
4726 is normally done. We are only interested in the type of the call
4727 expression, i.e., the return type of the function. Any semantic
4728 errors will be deferred until the template is instantiated. */
4730 {
4731 tree expr;
4732 tree return_type;
4740 }
4742 /* Give any warnings we noticed during overload resolution. */
4744 {
4748 }
4751 {
4752 /* If FN is a template function, two cases must be considered.
4753 For example:
4755 struct A {
4756 protected:
4757 template <class T> void f();
4758 };
4759 template <class T> struct B {
4760 protected:
4761 void g();
4762 };
4763 struct C : A, B<int> {
4764 using A::f; // #1
4765 using B<int>::g; // #2
4766 };
4768 In case #1 where `A::f' is a member template, DECL_ACCESS is
4769 recorded in the primary template but not in its specialization.
4770 We check access of FN using its primary template.
4772 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4773 because it is a member of class template B, DECL_ACCESS is
4774 recorded in the specialization `B<int>::g'. We cannot use its
4775 primary template because `B<T>::g' and `B<int>::g' may have
4776 different access. */
4781 else
4783 }
4789 /* The implicit parameters to a constructor are not considered by overload
4790 resolution, and must be of the proper type. */
4792 {
4796 /* We should never try to call the abstract constructor. */
4800 {
4801 converted_args = tree_cons
4805 }
4806 }
4807 /* Bypass access control for 'this' parameter. */
4809 {
4812 tree converted_arg;
4813 tree base_binfo;
4819 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4820 X is called for an object that is not of type X, or of a type
4821 derived from X, the behavior is undefined.
4823 So we can assume that anything passed as 'this' is non-null, and
4824 optimize accordingly. */
4826 /* Convert to the base in which the function was declared. */
4832 /* Check that the base class is accessible. */
4838 /* If fn was found by a using declaration, the conversion path
4839 will be to the derived class, not the base declaring fn. We
4840 must convert from derived to base. */
4851 }
4855 {
4860 /* Don't make a copy here if build_call is going to. */
4865 val = convert_like_with_context
4870 }
4872 /* Default arguments */
4874 converted_args
4879 converted_args);
4881 /* Ellipsis */
4883 {
4887 else
4890 }
4897 /* Avoid actually calling copy constructors and copy assignment operators,
4898 if possible. */
4903 {
4904 tree targ;
4908 /* Pull out the real argument, disregarding const-correctness. */
4915 {
4920 }
4921 else
4926 else
4929 /* [class.copy]: the copy constructor is implicitly defined even if
4930 the implementation elided its use. */
4934 /* If we're creating a temp and we already have one, don't create a
4935 new one. If we're not creating a temp but we get one, use
4936 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4937 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4938 temp or an INIT_EXPR otherwise. */
4940 {
4945 }
4948 {
4949 tree to = stabilize_reference
4954 }
4955 }
4959 {
4960 tree to = stabilize_reference
4967 {
4970 }
4971 else
4972 {
4973 /* We must only copy the non-tail padding parts.
4974 Use __builtin_memcpy for the bitwise copy. */
4987 }
4990 }
4995 {
5008 else
5011 }
5014 else
5018 }
5020 /* Build and return a call to FN, using ARGS. This function performs
5021 no overload resolution, conversion, or other high-level
5022 operations. */
5024 tree
5026 {
5027 tree fndecl;
5031 /* If this call might throw an exception, note that fact. */
5038 /* Some built-in function calls will be evaluated at compile-time in
5039 fold (). */
5052 }
5056 /* Make an expression which yields the address of the Java interface
5057 method FN. This is achieved by generating a call to libjava's
5058 _Jv_LookupInterfaceMethodIdx(). */
5060 static tree
5062 {
5068 {
5073 endlink)));
5074 java_iface_lookup_fn
5078 }
5080 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5081 This is the first entry in the vtable. */
5083 integer_zero_node);
5085 /* Get the java.lang.Class pointer for the interface being called. */
5090 {
5092 iface);
5094 }
5098 /* Determine the itable index of FN. */
5101 {
5106 i++;
5107 }
5115 java_iface_lookup_fn);
5117 }
5119 /* Returns the value to use for the in-charge parameter when making a
5120 call to a function with the indicated NAME.
5122 FIXME:Can't we find a neater way to do this mapping? */
5124 tree
5126 {
5137 /* This function should only be called with one of the names listed
5138 above. */
5141 }
5143 /* Build a call to a constructor, destructor, or an assignment
5144 operator for INSTANCE, an expression with class type. NAME
5145 indicates the special member function to call; ARGS are the
5146 arguments. BINFO indicates the base of INSTANCE that is to be
5147 passed as the `this' parameter to the member function called.
5149 FLAGS are the LOOKUP_* flags to use when processing the call.
5151 If NAME indicates a complete object constructor, INSTANCE may be
5152 NULL_TREE. In this case, the caller will call build_cplus_new to
5153 store the newly constructed object into a VAR_DECL. */
5155 tree
5158 {
5159 tree fns;
5160 /* The type of the subobject to be constructed or destroyed. */
5161 tree class_type;
5170 {
5171 /* Resolve the name. */
5176 }
5182 /* Handle the special case where INSTANCE is NULL_TREE. */
5184 {
5187 }
5188 else
5189 {
5195 /* Convert to the base class, if necessary. */
5198 {
5200 /* For constructors and destructors, either the base is
5201 non-virtual, or it is virtual but we are doing the
5202 conversion from a constructor or destructor for the
5203 complete object. In either case, we can convert
5204 statically. */
5206 else
5207 /* However, for assignment operators, we must convert
5208 dynamically if the base is virtual. */
5211 }
5212 }
5218 /* When making a call to a constructor or destructor for a subobject
5219 that uses virtual base classes, pass down a pointer to a VTT for
5220 the subobject. */
5224 {
5225 tree vtt;
5226 tree sub_vtt;
5228 /* If the current function is a complete object constructor
5229 or destructor, then we fetch the VTT directly.
5230 Otherwise, we look it up using the VTT we were given. */
5236 current_vtt_parm,
5237 vtt);
5243 }
5248 }
5250 /* Return the NAME, as a C string. The NAME indicates a function that
5251 is a member of TYPE. *FREE_P is set to true if the caller must
5252 free the memory returned.
5254 Rather than go through all of this, we should simply set the names
5255 of constructors and destructors appropriately, and dispense with
5256 ctor_identifier, dtor_identifier, etc. */
5260 {
5263 /* Assume that we will not allocate memory. */
5265 /* Constructors and destructors are special. */
5267 {
5268 pretty_name
5270 /* For a destructor, add the '~'. */
5274 {
5276 /* Remember that we need to free the memory allocated. */
5278 }
5279 }
5281 {
5284 TFF_PLAIN_IDENTIFIER),
5285 NULL);
5286 /* Remember that we need to free the memory allocated. */
5288 }
5289 else
5293 }
5295 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
5296 be set, upon return, to the function called. */
5298 tree
5302 {
5306 tree access_binfo;
5307 tree optype;
5309 tree name;
5310 tree user_args;
5311 tree call;
5312 tree fn;
5313 tree class_type;
5316 tree orig_instance;
5317 tree orig_fns;
5318 tree orig_args;
5323 /* We don't know what function we're going to call, yet. */
5333 {
5336 }
5342 /* Dismantle the baselink to collect all the information we need. */
5349 {
5353 }
5364 {
5367 }
5369 /* The USER_ARGS are the arguments we will display to users if an
5370 error occurs. The USER_ARGS should not include any
5371 compiler-generated arguments. The "this" pointer hasn't been
5372 added yet. However, we must remove the VTT pointer if this is a
5373 call to a base-class constructor or destructor. */
5376 {
5377 /* Callers should explicitly indicate whether they want to construct
5378 the complete object or just the part without virtual bases. */
5380 /* Similarly for destructors. */
5382 /* Remove the VTT pointer, if present. */
5386 }
5388 /* Process the argument list. */
5395 /* It's OK to call destructors on cv-qualified objects. Therefore,
5396 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5398 {
5403 }
5408 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5412 {
5414 tree this_arglist;
5416 /* We can end up here for copy-init of same or base class. */
5423 else
5427 /* A member template. */
5429 class_type,
5430 explicit_targs,
5432 access_binfo,
5433 conversion_path,
5434 flags,
5435 DEDUCE_CALL);
5438 class_type,
5439 this_arglist,
5440 access_binfo,
5441 conversion_path,
5442 flags);
5443 }
5447 {
5450 else
5451 {
5461 }
5464 }
5465 else
5466 {
5469 {
5475 user_args);
5480 }
5481 else
5482 {
5490 /* This is not an error, it is runtime undefined
5491 behavior. */
5493 "abstract virtual %q#D called from constructor"
5495 fn);
5499 {
5501 fn);
5503 }
5504 else
5505 {
5509 /* Now we know what function is being called. */
5512 /* Build the actual CALL_EXPR. */
5514 /* In an expression of the form `a->f()' where `f' turns
5515 out to be a static member function, `a' is
5516 none-the-less evaluated. */
5522 }
5523 }
5524 }
5527 call = (build_min_non_dep
5532 /* Free all the conversions we allocated. */
5536 }
5538 /* Returns true iff standard conversion sequence ICS1 is a proper
5539 subsequence of ICS2. */
5541 static bool
5543 {
5544 /* We can assume that a conversion of the same code
5545 between the same types indicates a subsequence since we only get
5546 here if the types we are converting from are the same. */
5553 {
5561 /* At this point, ICS1 cannot be a proper subsequence of
5562 ICS2. We can get a USER_CONV when we are comparing the
5563 second standard conversion sequence of two user conversion
5564 sequences. */
5574 }
5575 }
5577 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5578 be any _TYPE nodes. */
5580 bool
5582 {
5587 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5588 considers every class derived from itself. */
5591 }
5593 /* We build the ICS for an implicit object parameter as a pointer
5594 conversion sequence. However, such a sequence should be compared
5595 as if it were a reference conversion sequence. If ICS is the
5596 implicit conversion sequence for an implicit object parameter,
5597 modify it accordingly. */
5599 static void
5601 {
5603 {
5604 /* [over.match.funcs]
5606 For non-static member functions, the type of the
5607 implicit object parameter is "reference to cv X"
5608 where X is the class of which the function is a
5609 member and cv is the cv-qualification on the member
5610 function declaration. */
5612 tree reference_type;
5614 /* The `this' parameter is a pointer to a class type. Make the
5615 implicit conversion talk about a reference to that same class
5616 type. */
5627 }
5628 }
5630 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5631 and return the type to which the reference refers. Otherwise,
5632 leave *ICS unchanged and return NULL_TREE. */
5634 static tree
5636 {
5638 {
5645 }
5648 }
5650 /* Compare two implicit conversion sequences according to the rules set out in
5651 [over.ics.rank]. Return values:
5653 1: ics1 is better than ics2
5654 -1: ics2 is better than ics1
5655 0: ics1 and ics2 are indistinguishable */
5657 static int
5659 {
5660 tree from_type1;
5661 tree from_type2;
5662 tree to_type1;
5663 tree to_type2;
5670 /* REF_BINDING is nonzero if the result of the conversion sequence
5671 is a reference type. In that case TARGET_TYPE is the
5672 type referred to by the reference. */
5673 tree target_type1;
5674 tree target_type2;
5676 /* Handle implicit object parameters. */
5680 /* Handle reference parameters. */
5684 /* [over.ics.rank]
5686 When comparing the basic forms of implicit conversion sequences (as
5687 defined in _over.best.ics_)
5689 --a standard conversion sequence (_over.ics.scs_) is a better
5690 conversion sequence than a user-defined conversion sequence
5691 or an ellipsis conversion sequence, and
5693 --a user-defined conversion sequence (_over.ics.user_) is a
5694 better conversion sequence than an ellipsis conversion sequence
5695 (_over.ics.ellipsis_). */
5705 {
5706 /* XXX Isn't this an extension? */
5707 /* Both ICS are bad. We try to make a decision based on what
5708 would have happened if they'd been good. */
5716 /* We couldn't make up our minds; try to figure it out below. */
5717 }
5720 /* Both conversions are ellipsis conversions. */
5723 /* User-defined conversion sequence U1 is a better conversion sequence
5724 than another user-defined conversion sequence U2 if they contain the
5725 same user-defined conversion operator or constructor and if the sec-
5726 ond standard conversion sequence of U1 is better than the second
5727 standard conversion sequence of U2. */
5730 {
5744 /* We can just fall through here, after setting up
5745 FROM_TYPE1 and FROM_TYPE2. */
5748 }
5749 else
5750 {
5754 /* We're dealing with two standard conversion sequences.
5756 [over.ics.rank]
5758 Standard conversion sequence S1 is a better conversion
5759 sequence than standard conversion sequence S2 if
5761 --S1 is a proper subsequence of S2 (comparing the conversion
5762 sequences in the canonical form defined by _over.ics.scs_,
5763 excluding any Lvalue Transformation; the identity
5764 conversion sequence is considered to be a subsequence of
5765 any non-identity conversion sequence */
5776 }
5779 {
5784 }
5785 /* Otherwise, one sequence cannot be a subsequence of the other; they
5786 don't start with the same type. This can happen when comparing the
5787 second standard conversion sequence in two user-defined conversion
5788 sequences. */
5790 /* [over.ics.rank]
5792 Or, if not that,
5794 --the rank of S1 is better than the rank of S2 (by the rules
5795 defined below):
5797 Standard conversion sequences are ordered by their ranks: an Exact
5798 Match is a better conversion than a Promotion, which is a better
5799 conversion than a Conversion.
5801 Two conversion sequences with the same rank are indistinguishable
5802 unless one of the following rules applies:
5804 --A conversion that is not a conversion of a pointer, or pointer
5805 to member, to bool is better than another conversion that is such
5806 a conversion.
5808 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5809 so that we do not have to check it explicitly. */
5822 {
5827 }
5828 /* The rules for pointers to members A::* are just like the rules
5829 for pointers A*, except opposite: if B is derived from A then
5830 A::* converts to B::*, not vice versa. For that reason, we
5831 switch the from_ and to_ variables here. */
5838 {
5843 }
5848 {
5849 /* This was one of the pointer or pointer-like conversions.
5851 [over.ics.rank]
5853 --If class B is derived directly or indirectly from class A,
5854 conversion of B* to A* is better than conversion of B* to
5855 void*, and conversion of A* to void* is better than
5856 conversion of B* to void*. */
5859 {
5861 deref_from_type2))
5864 deref_from_type1))
5866 }
5869 {
5871 {
5873 {
5875 deref_to_type1))
5877 }
5878 /* We know that DEREF_TO_TYPE1 is `void' here. */
5880 deref_to_type2))
5882 }
5883 }
5886 {
5887 /* [over.ics.rank]
5889 --If class B is derived directly or indirectly from class A
5890 and class C is derived directly or indirectly from B,
5892 --conversion of C* to B* is better than conversion of C* to
5893 A*,
5895 --conversion of B* to A* is better than conversion of C* to
5896 A* */
5898 {
5900 deref_to_type2))
5903 deref_to_type1))
5905 }
5907 {
5909 deref_from_type1))
5912 deref_from_type2))
5914 }
5915 }
5916 }
5919 {
5922 /* [over.ics.rank]
5924 --binding of an expression of type C to a reference of type
5925 B& is better than binding an expression of type C to a
5926 reference of type A&
5928 --conversion of C to B is better than conversion of C to A, */
5931 {
5936 }
5937 }
5940 {
5943 /* [over.ics.rank]
5945 --binding of an expression of type B to a reference of type
5946 A& is better than binding an expression of type C to a
5947 reference of type A&,
5949 --conversion of B to A is better than conversion of C to A */
5952 {
5957 }
5958 }
5960 /* [over.ics.rank]
5962 --S1 and S2 differ only in their qualification conversion and yield
5963 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5964 qualification signature of type T1 is a proper subset of the cv-
5965 qualification signature of type T2 */
5971 /* [over.ics.rank]
5973 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5974 types to which the references refer are the same type except for
5975 top-level cv-qualifiers, and the type to which the reference
5976 initialized by S2 refers is more cv-qualified than the type to
5977 which the reference initialized by S1 refers */
5983 /* Neither conversion sequence is better than the other. */
5985 }
5987 /* The source type for this standard conversion sequence. */
5989 static tree
5991 {
5993 {
5998 }
6000 }
6002 /* Note a warning about preferring WINNER to LOSER. We do this by storing
6003 a pointer to LOSER and re-running joust to produce the warning if WINNER
6004 is actually used. */
6006 static void
6008 {
6014 }
6016 /* Compare two candidates for overloading as described in
6017 [over.match.best]. Return values:
6019 1: cand1 is better than cand2
6020 -1: cand2 is better than cand1
6021 0: cand1 and cand2 are indistinguishable */
6023 static int
6025 {
6031 /* Candidates that involve bad conversions are always worse than those
6032 that don't. */
6038 /* If we have two pseudo-candidates for conversions to the same type,
6039 or two candidates for the same function, arbitrarily pick one. */
6044 /* a viable function F1
6045 is defined to be a better function than another viable function F2 if
6046 for all arguments i, ICSi(F1) is not a worse conversion sequence than
6047 ICSi(F2), and then */
6049 /* for some argument j, ICSj(F1) is a better conversion sequence than
6050 ICSj(F2) */
6052 /* For comparing static and non-static member functions, we ignore
6053 the implicit object parameter of the non-static function. The
6054 standard says to pretend that the static function has an object
6055 parm, but that won't work with operator overloading. */
6058 {
6066 else
6067 {
6070 }
6071 }
6074 {
6080 {
6093 {
6100 else
6105 {
6109 }
6110 else
6112 }
6115 {
6118 }
6120 }
6121 }
6123 /* warn about confusing overload resolution for user-defined conversions,
6124 either between a constructor and a conversion op, or between two
6125 conversion ops. */
6129 {
6135 else
6138 /* We don't want to complain about `X::operator T1 ()'
6139 beating `X::operator T2 () const', when T2 is a no less
6140 cv-qualified version of T1. */
6143 {
6148 {
6151 }
6154 }
6155 else
6161 {
6169 }
6170 else
6172 }
6177 /* or, if not that,
6178 F1 is a non-template function and F2 is a template function
6179 specialization. */
6186 /* or, if not that,
6187 F1 and F2 are template functions and the function template for F1 is
6188 more specialized than the template for F2 according to the partial
6189 ordering rules. */
6192 {
6193 winner = more_specialized_fn
6196 /* [temp.func.order]: The presence of unused ellipsis and default
6197 arguments has no effect on the partial ordering of function
6198 templates. add_function_candidate() will not have
6199 counted the "this" argument for constructors. */
6203 }
6205 /* or, if not that,
6206 the context is an initialization by user-defined conversion (see
6207 _dcl.init_ and _over.match.user_) and the standard conversion
6208 sequence from the return type of F1 to the destination type (i.e.,
6209 the type of the entity being initialized) is a better conversion
6210 sequence than the standard conversion sequence from the return type
6211 of F2 to the destination type. */
6214 {
6218 }
6220 /* Check whether we can discard a builtin candidate, either because we
6221 have two identical ones or matching builtin and non-builtin candidates.
6223 (Pedantically in the latter case the builtin which matched the user
6224 function should not be added to the overload set, but we spot it here.
6226 [over.match.oper]
6227 ... the builtin candidates include ...
6228 - do not have the same parameter type list as any non-template
6229 non-member candidate. */
6233 {
6239 {
6241 /* Two built-in candidates; arbitrarily pick one. */
6244 /* cand1 is built-in; prefer cand2. */
6246 else
6247 /* cand2 is built-in; prefer cand1. */
6249 }
6250 }
6252 /* If the two functions are the same (this can happen with declarations
6253 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6258 tweak:
6260 /* Extension: If the worst conversion for one candidate is worse than the
6261 worst conversion for the other, take the first. */
6263 {
6268 {
6273 }
6279 {
6281 {
6283 ISO C++ says that these are ambiguous, even \
6284 though the worst conversion for the first is better than \
6288 }
6289 else
6292 }
6293 }
6297 }
6299 /* Given a list of candidates for overloading, find the best one, if any.
6300 This algorithm has a worst case of O(2n) (winner is last), and a best
6301 case of O(n/2) (totally ambiguous); much better than a sorting
6302 algorithm. */
6306 {
6311 /* Walk through the list once, comparing each current champ to the next
6312 candidate, knocking out a candidate or two with each comparison. */
6315 {
6319 else
6320 {
6322 {
6327 }
6328 else
6329 {
6332 }
6335 }
6336 }
6338 /* Make sure the champ is better than all the candidates it hasn't yet
6339 been compared to. */
6342 challenger != champ
6345 {
6349 }
6352 }
6354 /* Returns nonzero if things of type FROM can be converted to TO. */
6356 bool
6358 {
6360 }
6362 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6364 bool
6366 {
6371 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6375 flags);
6378 /* Free all the conversions we allocated. */
6382 }
6384 /* Like can_convert_arg, but allows dubious conversions as well. */
6386 bool
6388 {
6392 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6394 /* Try to perform the conversion. */
6396 LOOKUP_NORMAL);
6397 /* Free all the conversions we allocated. */
6401 }
6403 /* Convert EXPR to TYPE. Return the converted expression.
6405 Note that we allow bad conversions here because by the time we get to
6406 this point we are committed to doing the conversion. If we end up
6407 doing a bad conversion, convert_like will complain. */
6409 tree
6411 {
6418 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6423 LOOKUP_NORMAL);
6425 {
6428 }
6430 {
6431 /* In a template, we are only concerned about determining the
6432 type of non-dependent expressions, so we do not have to
6433 perform the actual conversion. */
6436 }
6437 else
6440 /* Free all the conversions we allocated. */
6444 }
6446 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6447 permitted. If the conversion is valid, the converted expression is
6448 returned. Otherwise, NULL_TREE is returned, except in the case
6449 that TYPE is a class type; in that case, an error is issued. If
6450 C_CAST_P is true, then this direction initialization is taking
6451 place as part of a static_cast being attempted as part of a C-style
6452 cast. */
6454 tree
6456 tree expr,
6458 {
6464 /* [dcl.init]
6466 If the destination type is a (possibly cv-qualified) class type:
6468 -- If the initialization is direct-initialization ...,
6469 constructors are considered. ... If no constructor applies, or
6470 the overload resolution is ambiguous, the initialization is
6471 ill-formed. */
6473 {
6478 }
6480 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6484 c_cast_p,
6485 LOOKUP_NORMAL);
6488 else
6491 c_cast_p);
6493 /* Free all the conversions we allocated. */
6497 }
6499 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6500 is being bound to a temporary. Create and return a new VAR_DECL
6501 with the indicated TYPE; this variable will store the value to
6502 which the reference is bound. */
6504 tree
6506 {
6507 tree var;
6509 /* Create the variable. */
6512 /* Register the variable. */
6514 {
6515 /* Namespace-scope or local static; give it a mangled name. */
6516 tree name;
6523 }
6524 else
6525 /* Create a new cleanup level if necessary. */
6529 }
6531 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6532 initializing a variable of that TYPE. If DECL is non-NULL, it is
6533 the VAR_DECL being initialized with the EXPR. (In that case, the
6534 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6535 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6536 return, if *CLEANUP is no longer NULL, it will be an expression
6537 that should be pushed as a cleanup after the returned expression
6538 is used to initialize DECL.
6540 Return the converted expression. */
6542 tree
6544 {
6551 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6556 {
6562 else
6567 }
6569 /* If DECL is non-NULL, then this special rule applies:
6571 [class.temporary]
6573 The temporary to which the reference is bound or the temporary
6574 that is the complete object to which the reference is bound
6575 persists for the lifetime of the reference.
6577 The temporaries created during the evaluation of the expression
6578 initializing the reference, except the temporary to which the
6579 reference is bound, are destroyed at the end of the
6580 full-expression in which they are created.
6582 In that case, we store the converted expression into a new
6583 VAR_DECL in a new scope.
6585 However, we want to be careful not to create temporaries when
6586 they are not required. For example, given:
6588 struct B {};
6589 struct D : public B {};
6590 D f();
6591 const B& b = f();
6593 there is no need to copy the return value from "f"; we can just
6594 extend its lifetime. Similarly, given:
6596 struct S {};
6597 struct T { operator S(); };
6598 T t;
6599 const S& s = t;
6601 we can extend the lifetime of the return value of the conversion
6602 operator. */
6605 {
6606 tree var;
6607 tree base_conv_type;
6609 /* Skip over the REF_BIND. */
6611 /* If the next conversion is a BASE_CONV, skip that too -- but
6612 remember that the conversion was required. */
6614 {
6619 }
6620 else
6622 /* Perform the remainder of the conversion. */
6630 else
6631 {
6633 {
6634 tree init;
6635 tree type;
6637 /* Create the temporary variable. */
6641 /* If the rvalue is the result of a function call it will be
6642 a TARGET_EXPR. If it is some other construct (such as a
6643 member access expression where the underlying object is
6644 itself the result of a function call), turn it into a
6645 TARGET_EXPR here. It is important that EXPR be a
6646 TARGET_EXPR below since otherwise the INIT_EXPR will
6647 attempt to make a bitwise copy of EXPR to initialize
6648 VAR. */
6651 /* Create the INIT_EXPR that will initialize the temporary
6652 variable. */
6655 {
6659 /* We must be careful to destroy the temporary only
6660 after its initialization has taken place. If the
6661 initialization throws an exception, then the
6662 destructor should not be run. We cannot simply
6663 transform INIT into something like:
6665 (INIT, ({ CLEANUP_STMT; }))
6667 because emit_local_var always treats the
6668 initializer as a full-expression. Thus, the
6669 destructor would run too early; it would run at the
6670 end of initializing the reference variable, rather
6671 than at the end of the block enclosing the
6672 reference variable.
6674 The solution is to pass back a cleanup expression
6675 which the caller is responsible for attaching to
6676 the statement tree. */
6677 }
6678 else
6679 {
6683 static_aggregates);
6684 }
6685 /* Use its address to initialize the reference variable. */
6693 }
6694 else
6695 /* Take the address of EXPR. */
6697 /* If a BASE_CONV was required, perform it now. */
6699 expr = (perform_implicit_conversion
6702 }
6703 }
6704 else
6705 /* Perform the conversion. */
6708 /* Free all the conversions we allocated. */
6712 }